Acidification and its policy implications: proceedings of an international conference held in Amsterdam, May 5-9, 1986

Studies in Environmental Science 30 ACIDIFICATION AND ITS POLICY IMPLICATIONS Proceedings of an International Conferen...

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Studies in Environmental Science 30

ACIDIFICATION AND ITS POLICY IMPLICATIONS Proceedings of an International Conference held in Amsterdam, May 5-9,1986

Organized by the Government of The Netherlands i n cooperation with the United Nations Economic Commission for Europe (ECE)

Edited by

T. Schneider

National institute of Public Health and Environmental Hygiene fRI VM), Bil thoven, The Netherlands

E LSEV I E R Amsterdam - Oxford - New York - Tokyo

1986

ELSEVIER SCIENCE PUBLISHERS B.V. Sara Burgerhartstraat 25 P.O. Box 2 1 1, 1000 AE Amsterdam, The Netherlands Distributors for rhe Unired Stares and Canada:

ELSEVIER SCIENCE PUBLISHING COMPANY INC. 52, Vanderbilt Avenue New York, NY 10017, U.S.A.

Library of C o n y - GtaloginginPublir.tion D.b

Acidification and i t s p o l i c y implications. (Studies i n environmental science ; 30) Includes index. 1. Acid deposition--Environmental aspects--Congresses. 2. S o i l acidification--Congresses. I . Schneider, T. ( TOMY 1, 193511. United Nations. Economic Conmission for Europe. 111. Conference on Acidification Md Its Policy Impliee-ticns (19% : Amsterdam, Netherlands ) I V . Series. ~ O i g 6 . ~ 2 5 A 3 51906 363.7’386 86-24080 ISBN 0-4h4-42725-2 (U.S. )

.

ISBN 0-444-42725-2 (Vol. 30) ISBN 0-444-4 1696-X (Series) 0 Elsevier Science Publishers B.V., 1986

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the publisher, Elsevier Science Publishers B.V./ Science &Technology Division, P.O. Box 330, 1000 AH Amsterdam, The Netherlands. Special regulations for readers in the USA - This publication has been registered with the Copyright Clearance Center Inc. (CCC), Salem, Massachusetts. Information can be obtained from the CCC about conditions under which photocopies of parts of this publication may be made in the USA. All other copyright questions, including photocopying outside of the USA, should be referred t o the publisher. Printed in The Netherlands

IX

FOREWORD

The i n t e r n a t i o n a l Conference on A c i d i f i c a t i o n and i t s P o l i c y I m p l i c a t i o n s , o r g a n i z e d by t h e Government o f The Netherlands, i n c o o p e r a t i o n w i t h t h e U n i t e d Nations

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Economic Commission f o r Europe (ECE), was h e l d i n Amsterdam,

The Netherlands, 5

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9 May 1986.

I n June 1984 about 30 c o u n t r i e s met i n Munich ( F e d e r a l R e p u b l i c o f Germany) t o r e v i e w t h e s e r i o u s d e t e r i o r a t i o n o f n a t u r a l environments i n Europe and N o r t h e r n America. Consensus was reached on t h e s e r i o u s n e s s o f t h e problem. The t h i r d s e s s i o n o f t h e E x e c u t i v e Body i n J u l y 1985

i n H e l s i n k i confirmed t h i s

view. The c o u n t r i e s p a r t i c i p a t i n g i n t h e Munich Conference, aware t h a t a c i d i f i c a t i o n i s an e x t r e m e l y complex phenomenon, agreed t o r e v i e w r e g u l a r l y t h e s t a t e o f s c i e n t i f i c knowledge i n t h i s f i e l d . M i n i s t e r Winsemius o f f e r e d , on b e h a l f o f The N e t h e r l a n d s Government, t o h o s t t h e f i r s t meeting. The ECE a t i t s 4 0 t h s e s s i o n i n A p r i l 1985 welcomed t h e i n i t i a t i v e o f t h e Government o f The N e t h e r l a n d s t o h o l d t h e Conference i n c o o p e r a t i o n w i t h t h e ECE. The Conference was a t t e n d e d by more t h a n 300 people f r o m 26 c o u n t r i e s i n c l u d i n g 24 o f f i c i a l d e l e g a t i o n s f r o m ECE member c o u n t r i e s . The proceedings f r o m t h e Conference c o n t a i n t h e f u l l opening statements by P.Winsemius,

M i n i s t e r o f Housing, P h y s i c a l P l a n n i n g and Environment o f The Neth-

e r l a n d s and K.A.Sahlgren,

E x e c u t i v e S e c r e t a r y U.N.

Economic Commission f o r Europe,

The Opening Session was f o l l o w e d by a Session on t h e E f f e c t s i n t h e Environment, where a number o f r e v i e w papers on t h e d i f f e r e n t e f f e c t s i n e n v i r o n m e n t a l media were presented. Next t o t h e e f f e c t s on t h e a q u a t i c environment,

e f f e c t s on f l o r a ,

fauna and v e g e t a t i o n , a l s o e f f e c t s on m a t e r i a l s , c u l t u r a l p r o p e r t i e s , t h e ecol o g y as a whole and t h e economic impact o f a c i d i f i c a t i o n were reviewed. The second day o f t h e Conference was d e d i c a t e d t o a d e t a i l e d i n t r o d u c t i o n o f forest-dieback:

t h e p o t e n t i a l s t r e s s f a c t o r s and t h e e f f e c t s on m a t e r i a l s and

c u l t u r a l p r o p e r t i e s . The f i n a l s e s s i o n o f t h e p r e s e n t a t i o n s o f s c i e n t i f i c r e s e a r c h r e s u l t s d e a l t w i t h models as t o o l s f o r abatement s t r a t e g i e s . E s p e c i a l l y t h e a p p l i c a t i o n o f models i n p o l i c y making was u n d e r l i n e d . F i n a l l y a g e n e r a l e f f e c t s o v e r v i e w was g i v e n by t h e Chairman o f t h e Conference, D.3.Kuenen. The r e v i e w papers o f s c i e n t i f i c r e s e a r c h on a c i d i f i c a t i o n a r e f o l l o w e d by t h e o f f i c i a l r e p o r t o f t h e Conference p r e s e n t e d w i t h i n t h e ECE c o n t e x t . T h i s r e p o r t i s f o l l o w e d by t h e n a t i o n a l p r e s e n t a t i o n s , as g i v e n on t h e f o u r t h day o f

X t h e Conference, b y r e p r e s e n t a t i v e s o f ECE member c o u n t r i e s . These n a t i o n a l contributions dealt

w i t h t h e o v e r v i e w s o f n a t i o n a l r e s e a r c h programmes and p o l i c i e s

regarding a c i d i f i c a t i o n .

These c o n t r i b u t i o n s a r e f o l l o w e d by t h e f i n a l remarks

o f P.Winsemius made d u r i n g t h e C l o s i n g Session o f t h e Conference. A l s o i n c l u d e d i n t h e s e proceedings a r e a s u b j e c t i n d e x r e f e r r i n g t o t h e papers d e s c r i b i n g t h e s c i e n t i f i c r e s e a r c h r e s u l t s , a l i s t o f o f f i c i a l d e l e g a t i o n s f r o m t h e ECE member c o u n t r i e s and f i n a l l y a complete l i s t o f a l l p a r t i c i p a n t s t o t h e meeting. The s u c c e s s f u l conduct o f an i n t e r n a t i o n a l conference o f t h e magnitude o f t h i s f i r s t Conference on A c i d i f i c a t i o n and i t s P o l i c y I m p l i c a t i o n s i n Amsterdam, depends on t h e c o o p e r a t i o n and d e d i c a t i o n o f numerous i n d i v i d u a l s and groups t o whom t h e p r e s e n t e d i t o r , Chairman o f t h e O r g a n i z i n g Committee f o r t h e Conference, i s d e e p l y i n d e b t e d . I t would be i m p o s s i b l e t o acknowledge h e r e a l l t h o s e who c o n t r i b u t e d i n many ways t o t h e o r g a n i z a t i o n o f t h e Conference and i t s a s s o c i a t e d e v e n t s , as w e l l as t o t h e subsequent p r e p a r a t i o n f o r p u b l i c a t i o n o f t h e p r e s e n t proceedings. I would l i k e , however, t o express my s i n c e r e a p p r e c i a t i o n t o a number o f s p e c i f i c i n d i v i d u a l s whose v e r y h a r d work and c o o p e r a t i o n c o n t r i b u t e d t o t h e f i n a l success o f t h e Conference. The o r g a n i z a t i o n o f t h e A c i d i f i c a t i o n Conference, e s p e c i a l l y t h e p r e p a r a t i o n o f t h e f i n a l programme was made p o s s i b l e w i t h t h e a i d o f t h e members o f t h e N a t i o n a l A d v i s o r y Committee, l i s t e d i n t h e p r e s e n t volume, t h e Session Chairmen and Rapporteurs. I n p a r t i c u l a r I would l i k e t o m e n t i o n D.J.Kuenen,

who

also

s e r v e d as t h e g e n e r a l Chairman f o r t h e whole Conference. A t a s k he f u l f i l l e d w i t h f i r m n e s s , w i t h f u l l a p p r e c i a t i o n o f t h e s c i e n t i f i c c o n t e n t o f t h e meeting, and above a l l w i t h d e d i c a t i o n . I am e s p e c i a l l y a p p r e c i a t i v e o f t h e e x c e l l e n t work performed by J.van Ham o f SCMO-TNO, who served as i n t e r n a t i o n a l s e c r e t a r y t o t h e whole Conference, t o S.Zwerver and W.J.Kakebeeke

f r o m t h e M i n i s t r y o f Housing, P h y s i c a l P l a n n i n g and

Environment, as a c t i v e members o f t h e O r g a n i z i n g Committee, t o t h e members o f t h e Conference Bureau, Mrs.O.van Mrs.L.Reijchard,

S t e e n i s , Mrs.P.W.A.M.Venis-Pols

and

w i t h o u t whom t h e o r g a n i z a t i o n o f t h e Conference and i t s success-

f u l conduct would n o t have been p o s s i b l e .

I am a l s o g r a t e f u l f o r t h e e x c e l l e n t

o r g a n i z a t i o n and c o n d u c t o f t h e p r o g r a m e f o r accompanying guests by Mrs.M.Schneider

and f o r t h e o r g a n i z a t i o n o f t h e two r e c e p t i o n s and t h e b o a t t r i p

t h r o u g h t h e Canals o f Amsterdam by t h e Burgomaster and Aldermen o f t h e c i t y o f Amsterdam and Mrs.A.M.J.Smits

van Oyen and Mrs.M.J.C.Nooteboom

from t h e

M i n i s t r y o f P u b l i c Housing, P h y s i c a l P l a n n i n g and Environment. Thanks a r e a l s o due t o t h e N a t i o n a l I n s t i t u t e o f P u b l i c H e a l t h and Environmental Hygiene i n B i l t h o v e n , t h e power s t a t i o n G e l d e r l a n d i n Nijmegen, t h e I n s t i t u t e f o r P l a n t P r o t e c t i o n i n Wageningen, t h e KEMA i n Arnhem en Geosens B.V.

i n Rotterdam f o r

t h e o r g a n i z a t i o n o f t h e t e c h n i c a l v i s i t s d u r i n g t h e Conference.

The c o n s i d e r a b l e

XI

a s s i s t a n c e and i n t e r e s t of members of these above mentioned i n s t i t u t e s c e r t a i n l y contributed t o t h e success of t h e Conference. Of extremely g r e a t value t o t h e Organizing Committee was a l s o t h e e x c e l l e n t help given by t h e representatives of t h e M a r r i o t t Hotel, Amsterdam, venue of t h e Conference, J.Heesbeen and co-workers, by J a c o t f o r technical a s s i s t a n c e and t r a n s l a t i o n f a c i l i t i e s , by W.van Doorn f o r s l i d e presentations during the Conference, by Mrs.A.Trottier, Mrs.C.Marteau, A.Dorogi, Mrs.N.Sideris, V.Poliakov, Mrs.G.Levitina and Mrs.G.Nar6chal f o r the t r a n s l a t i o n d u r i n g the Conference, by E l s e v i e r Science Publishers B.V., Mrs.H.Manten, f o r t h e rapid and successful presentation of these proceedings and f i n a l l y a special word of thanks i s due t o Mrs.O.van Steenis who took a l s o care o f the f i n a l preparations f o r these proceedings, including a l a r g e number of changes, c o r r e c t i o n s and adjustments i n the prepared papers, i n time t o meet the t h e deadline f o r publication. I hope t h a t these proceedings from t h e International Conference on Acidification and i t s Policy Implications, w i l l be helpful as a reference volume, both f o r research s c i e n t i s t s and policy makers.

T. Schneider National I n s t i t u t e of Public Health and Environmental Hygiene (RIVM) , Bi 1thoven, The Netherlands

3

T.Schneider (Editor)/Acidificationand its Policy Implications Elsevier Science PublishersB.V., Amsterdam - Printed in The Netherlands Opening address by dr. P. Winsemius Minister of Housing, Physical Planning and the Environment

WELCOME Excellencies, Mr. Executive Secretary, esteemed deleqates, ladies and gentlemen, It is an honour and a pleasure for me to welcome you all to this conference in Amsterdam.

WHY AND WHEREFORE OF THIS CONFERENCE This conference, organized by the Government of the Netherlands in cooperation with the United Nations Economic Commission for Europe, results from the acidification conference held in Munich in June 1984 (Multilateral conference on the causes and prevention of Damage to Forests and Waters by Air Pollution in Europe). The purpose of the conference is to make research results in the area of acidification internationally available as quickly as possible and to make it possible to translate those results into policy. That policy to control acidification must be developed and implemented is something I do not have to tell this company and my political colleagues. It is possible that not everyone is prepared to undertake the same level of action, but there is no difference of opinion about the potential, very serious consequences of acidification. During the environmental conference in Munich in 1984, the Ministers present concluded that even more intensive cooperation in the framework of the ECE Convention on Long Range Transboundary Air Pollution is needed. The

lath

and final paragraph of the resolution adopted in Munich asks the countries to lend their support to the Executive Body for the Convention (EB1 in executinq its task in the field of information exchange. Countries can do this by holding regular international symposia under the aegis of the UN Economic Commission for Europe to discuss the most recent scientific information relating to acidification and long range transboundary air pollution and its policy implications. I agree with this and while in Munich I offered to host the first conference.

4

The timely contribution of research results from the various countries is necessary. Real and coordinated political action in the area of acidification must be founded on a broad contribution of information from all countries. The underlyinq premise of environmental policy is protection of the weakest links in the environment. It is not then so important where that is and where the necessary action can best be taken, but it does mean that the information must be known. International solidarity begins with taking note of problems and solutions elsewhere, but also means beinq prepared to actually work on solvinq problems elsewhere. Almost ten years after publication of the report “Long range transport of air pollutants“, with which the OECD, present here now as an observer, planted the seed for this week‘s topic, there can be no doubt that in coming to the ECE we have come to the riqht place. It is the most appropriate forum that

contains the reqions in Europe and North America where the acidification problem has amalqated into one whole. A s an aside passing

-

-

but certainly not just in

I want to express admiration for the Nordic Countries, who

successfully brouqht the problem of “long range transport of air pollutants“ and acidification to the ECE level. It also inspires satisfaction that countries with different structures and systems have started to cooperate in this field in Europe. During this conference we will extend a measuring tape to take the measure of the condition of our knowledqe. I am convinced that our separate knowledqe, when brouqht together, will prove to be more than the sum of the separate parts. But our knowledge must also be qreater than it was in Munich, now that many countries have expanded their research and drawn up programmes. The questions that we must address, and that we hope to answer or to bring closer to an answer in the conference summary and conclusions, are: What directions are emerqinq in the research? Is there more certainty and new information aboutthe extent of effects?

Is there more information about the causes; about the substances, elements (for example, about nitroqen) that play

a

major role? Has the problem

been covered sufficiently with sulfur and nitrogen? Should hydrocarbons and ozone also be tackled?

Is there more clarity, more insight into the speed with which the effects strike? Does this make it necessary to adjust the pace of the abatement effort? Is there more clarity about the levels of these substances at which possible effects appear and the levels that are acceptable?

5

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Is recovery of damaged ecosystems still possible? What is the situation with our cultural monuments?

Is replanting the only hope for our forests? In that case, are temporary management measures possible and desirable?

The speakers from the various member countries will undoubtedly have spent lonq hours pondering such simple, but difficult to answer questions, while preparing their contributions to this conference. UNCERTAINTIES It is certain that acidification is an international problem whose cause and mechanism have not yet been completely explained scientifically in all details. There is little doubt about the effects. It may be expected from guests in the environment

-

and we are guests in the environment

-

that they

will behave responsibly with this knowledge about effects and not leave the bill to be paid by future generations. The underlying premise, protection of the weakest link in the environment, assigns responsibility to science and politics. Science must find the weakest link and indicate the most adequate action. Politics must ask the question: "Are we willing to undertake action?" And then there is a problem, because not everything is equally certain or aqreable. Our knowledge of acidification processes must still be described as knowledge of a "black box" to some extent. We know what goes into the box and we know something of what comes out, namely effects that usually become manifest much later or elsewhere. As lonq as the processes have not all been unravelled and sifted out, there is room for interpretation and we are compelled to take uncertainties into account. The point, in my opinion, is not just the existence of uncertainties, but how we handle them and decide when it is time for action. How we deal with this uncertainty is crucial. The factory manager who sees that something is going wrong but does not do anything until he is absolutely certain, will not remain manager much longer. The question for the politician is: where and when is it going wrong, how much room for action is there, and how much time do I have? Of course, it becomes difficult

-

politicians are also just people

-

if the

costs are here and the benefits are somewhere else. My former Austrian colleague, Dr. Kurt Steyer Environmental Protection

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-

former Austrian Minister for Health and

developed the notion of an International Fund for

6

t h e Environment i n a guest a r t i c l e i n t h e IIASA p u b l i c a t i o n "Options". H e b e l i e v e s t h a t t h e i n t e r n a t i o n a l community of states should t r y t o f i n d ways and means of e s t a b l i s h i n g coordinated f i n a n c i n g a c t i v i t i e s i n t h e various p a r t s and t h e v a r i o u s systems of our world. This notion runs p a r a l l e l t o suggestions t h a t I brought t o t h e f o r e on January 2 9 t h of t h i s year a t t h e conference on E x i s t i n g Chemicals i n Brussels and on l a t e r occasions. I have t h e impression t h a t analogous i d e a s a r e a l s o c i r c u l a t i n g i n o t h e r Western European c o u n t r i e s . I b e l i e v e t h a t D r .

S t e y e r ' s proposal h i t s t h e n a i l on t h e

head. H i s proposal combines, i n p r i n c i p l e , u n c e r t a i n t y and t h e i n t e r e s t t h e p a r t i e s have i n a c t i o n very e l e g a n t l y . Various p o l i c y models f o r t h e approach t o a c i d i f i c a t i o n e x i s t . A t t h e extremes a r e t h e model i n which nothing i s done u n t i l complete c e r t a i n t y e x i s t s , and t h e model i n which abatement i s begun immediately and c o r r e c t e d along t h e way. Reluctantly, b u t it i s what I know b e s t , I want t o e l u c i d a t e t h e l a t t e r model based on t h e choice t h a t we have made. In t h e beginning, t h e Netherlands l e t i t s e l f be l e d by t h e alarming f a c t s t h a t came i n from o u t s i d e . Weak l i n k s i n t h e environment have been manifest o u t s i d e our country f o r years. During t h e p a s t t e n t o twenty years, damage t o l a k e s and f o r e s t s have been r e p o r t e d with i n c r e a s i n g frequency. F i r s t t h e lakes i n t h e Nordic c o u n t r i e s , t h e U.S.

and Canada, l a t e r t h e f o r e s t s i n

Central Europe were added. Damage and i n j u r y w e r e reported f o r water, s o i l , v e g e t a t i o n , monuments and c u l t u r a l property and m a t e r i a l s . Often, t h e e f f e c t

i s delayed. This i n e r t i a l e f f e c t i s f r e q u e n t l y l a r g e and s t r u c t u r a l . Recovery i s not simple. An inventory showed t h a t much of t h e damage r e p o r t e d elsewhere was a l s o p r e s e n t i n our country. Given

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d a t a about c e r t a i n s e n s i t i v e s o i l s i n Sweden and Canada, and t h e nature of our own s o i l

w e decided t o set o u t a goal f o r t h e f u t u r e now and t o draw up a package of measures f o r a t t a i n i n g it. I t seems more e f f i c i e n t t o us t o i n s t i t u t e measures now than t o possibly be forced l a t e r t o undertake a much l a r g e r e f f o r t with much higher c o s t s . J o i n t research with i n d u s t r y i s guiding t h e package of measures. Two kinds of research a r e involved: 1 . The r e l a t i o n s h i p between cause and e f f e c t 2 . The e f f e c t of t h e measures.

Based on t h e r e s u l t s of t h i s r e s e a r c h , t h e measures w i l l be c o r r e c t e d i f necessary.

7

The other model postpones action until everything has been verified and the conclusions are clear. It has the advantage that no unnecessary costs in retrospect

-

-

seen

are incurred. But it also carries the risk of confronting us

with damage that cannot be corrected or can be corrected only with very high costs. The chance is slight that this model's ultimate cost-effectiveness is high. Which of the two models is ultimately the most effective remains to be seen. It is a matter of fairness to extend the evaluation to environmental effects and benefits in all of Europe, and not to limit it to one region. I have dwelt on this subject because I am interested in how other countries deal with uncertainty. I hope the conference will generate more information about this. Need for international cooperation Acidification is an international problem urgently requiring international cooperation. I want to illustrate this point with the following short film. It also shows the possibilities of models. Results of calculations converted into pictures give a direct overview that is not possible with words. In this case, it concerns SO2 and SO4 pollution that migrates across large parts of Europe. Based on estimated SO2 emissions in Europe, the model simulates the high air pollution episode of January 1985, when authorities announced a smog-alarm in the German Ruhr area. A high pressure system over the Baltics provided for eastward circulation over

Central Europe. There was very little wind and atmospheric conditions were stable. In short, a meteorological situation providing for an accumulation in air pollution. Because the ground was covered with snow, deposition was also less than it would have been otherwise. sulfate formed in the atmosphere from SO2

This led to SO2

-

and

- being transported farther than

they would have been in other circumstances. The second part of the film depicts the same situation for NOx and nitrate.

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It is clear that no matter where and how Europe is separated and unified politically or administratively

-

the environment binds us together. Air is

the most rapid connection. It takes only a few days for the atmosphere to transfer the side-effects of activities elsewhere.

8

Earlier I mentioned the OECD report on long range transport of air pollutants. This remains a clear beacon from the moment when transboundary air pollution and acidification began to receive broad international attention. Looking back, a lot has been done since then relating both to international consultation and to research, with a clear acceleration in recent years. The ECE Convention on Long Range Transboundary Air Pollution about in 1979

-

-

brought

entered into force in 1983. One year earlier, in 1982, the

first ECE conference on acidification was held in Stockholm. There, data, concerning the damage to forests in West Germany especially, were widely publicized for the first time. The base was laid for what is known as the S02-protocol at the ECE acidification conference in Munich ib 1984. The conference asked the "Executive Body of the Convention on/Long Range /

Transboundary Air Pollution" to adopt a "proposal for a specific agreement on the reduction of annual national sulfur emissions or their transboundary fluxes by 1993 at the latest." In signing the S02-protocol to the Convention on Long Range Transboundary Air Pollution in Helsinki last July, 21 ECE-countries explicitly acknowledged that :

-

damage to forests and lakes from man-made pollution in the atmosphere is an international problem

-

a start must be made with measures SO2

contributes significantly and must be tackled in any case.

Among the countries who did not sign, incidentally, there are those who agree with this but for whom signing was difficult, for example because they had already instituted measures. The formation of an ad-hoc NOx working group was another important step taken in Helsinki. Among other things, they were charged with reporting on proposals for reducing NOx emissions at the next meeting of the Executive Body. The Executive Body also coordinates an extensive work programme, containing the cooperative programme for the monitoring and evaluation of the long range transmission of air pollutants in Europe (EMEP), and studies of effects and technology. It is admirable that all of this has been brought about internationally in a fairly short time, thanks partly to the active secretariat of the ECE.

9

The question remains, however, whether the pace of our international abatement effort is fast enough. It is of great importance that 'with a speedy information exchange' we establish this as quickly as possible. DEVELOPMENTS FOR WHICH SPECIAL ATTENTION IS REQUIRED The first step in international control of acidification was taken in Helsinki last July with the signing of the protocol on the reduction of sulfur emissions or their transboundary fluxes. This step must still be taken for N&.

The foundation for the realization of such an agreement is currently

being prepared by a working group of the Executive Body. It will be of particular importance to learn from research whether there is a chance to reduce acidification sufficiently on an international basis. NO, is a key component. It contributes to soil acidification and together with hydrocarbons is responsible for the formation of ozone. It will be especially important to learn the degree of NOx control desired, because we are still at the beginning of the decision-making process for this component. Moreover, I understand that experts stress the role of nitrogen in soiL acidification more strongly. I have been told that that was also clear at the workshop in O s l o last

month on deposition guide values for sulfur and nitrogen compounds that was organized at the initiative of the Nordic Council of Ministers. A value in the order of magnitude of 5-20 kilograms nitrogen per hectare per year was contemplated there. In comparison, our estimate of nitrogen deposition is in the range of two kilograms per hectare per year in Northern Scandinavia to approximately forty kilograms per hectare per year in Western and Central Europe. We know that products of photochemical air pollution such as ozone cause damage to vegetation. That has been shown repeatedly in experiments. Not only high peaks of short duration are responsible. Prolonged exposure to relatively low concentrations could also cause effects. The damage from ozone to forests but also, for example, to agriculture and public health

-

not only is

considerable. This plus the large scale character of ozone places extra emphasis on the need €or international control of NOx and C,Hy

(hydrocarbons).

10

The forest in Europe Suffers intensively from either acidification of the soil

OK

damage from ozone. But air pollution also damages the harvest. It

surprises me a bit that this damage receives so little international attention. We estimate the reduction in

OUK

crop yield at circa 5 percent. The

damage that comes from this amounts to circa 250 million U.S.

dollars per

year. Translated to the Europe scale, this would near an amount in the order of four thousand million U.S. dollars. Even though this figure is uncertain or speculative, it seems worth thinking about, certainly for those countries whose economies depend on large areas of agricultural land. EXPECTATIONS FROM THIS CONFERENCE The points sketched previously show how important it is for international environmental policy to be informed quickly about the results of research. The design of this conference is such that, in any case

-

the countries can become acquainted with each other's research and its results, so that mutual support becomes possible, double effort can be

-

avoided but also gaps can be identified, there will be a start toward converting research results into acidification abatement policy. And not only within individual countries, but jointly.

But I expect still more from this conference. I expect that this conference will also mean actual support for the Executive Body in carrying out its work programme. This means that exactly those questions with which I began are on the agenda. It is very important to find answers for those questions, even if the answers are not complete. We must know the extent of effects of acidification; how fast the effects appear; what we can do and how quickly we should do it; and what environmental burden is acceptable. Based on the answers, the Executive Body will be able to evaluate the pace of its work programme. Whether

OK

not this conference will be successful will be shown from what

the Executive Body can do with the results. It will also show whether repeating this conference every two or three years, for example, is useful.

11

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands STATEMENT BY MR.KLAUS A.SAHLGREN,

EXECUTIVE SECRETARY OF THE ECONOMIC

COMMISSION FOR EUROPE, TO THE INTERNATIONAL CONFERENCE ON ACIDIFICATION AND ITS POLICY IMPLICATIONS (AMSTERDAM, 5 MAY 1986)

Mr.Minister,

I am

D i s t i n g u i s h e d Delegates, L a d i e s and Gentlemen,

very

pleased

International

to

Conference

join on

you

at

this

Acidification

opening

and

o r g a n i z e d by t h e Government o f The N e t h e r l a n d s

session

the

of

i t s Policy Implications,

in

co-operation

with

The

Netherlands,

and

the

U n i t e d N a t i o n s Economic Commission f o r Europe. We a l l a p p r e c i a t e t h e i n i t i a t i v e t a k e n by p e r s o n a l i n t e r e s t , Mr.Minister, t o thank you f o r y o u r Government

of

thoughtful

and

-

stimulating

opening

address.

through

global,

international

regional

and

action

bilateral

against

on

Long-range

Transboundary

Air

Pollution.

comes a t a c r i t i c a l t i m e , when p o l i c y guidance based

on

air

-

programmes

e s p e c i a l l y i n i t s s t r o n g s u p p o r t f o r ECE environmental programmes Convention

The

The Netherlands has t r a d i t i o n a l l y p l a y e d a v e r y a c t i v e r o l e

i n t h e p r o m o t i o n and i m p l e m e n t a t i o n o f pollution

your

i n t h i s i m p o r t a n t event. Moreover, a l l o w me

and

the

T h i s Conference sound

scientific

e v i d e n c e i s i n g r e a t demand. A c i d i f i c a t i o n i s a c e n t r a l environmental problem f o r region

which

comprises

resources

on which we depend

-

b u t even o u r

buildings

and

our

-

region

a

a l l o f Europe and N o r t h America. We have begun t o

r e a l i z e t h a t i t not only a f f e c t s our material well-being resources

and

-

cultural

monuments

and

the

natural

s o i l , f o r e s t s , f r e s h w a t e r s and t h e i r l i v i n g heritage,

crumbling

away

as under

we

see the

our

historical

silent

force

of

atmospheric p o l l u t a n t s . L e t me g i v e you a b r i e f run-down on where we s t a n d w i t h r e s p e c t t o pollution

activities.

P o l l u t i o n , which e n t e r e d i n t o f o r c e i n 1983 and f o r which secretariat,

has

been

we

provide

EMEP

has

been

financing

r a t i f i e d by 13 o f i t s 22 S i g n a t o r i e s ; and t h e P r o t o c o l

adopted i n J u l y i n H e l s i n k i on t h e r e d u c t i o n o f s u l p h u r emissions o f transboundary

the

r a t i f i e d by 31 o f t h e 35 S i g n a t o r i e s , and t h e 32nd

r a t i f i c a t i o n i s now underway. The 1984 P r o t o c o l on t h e l o n g - t e r m of

air

The 1979 Convention on Long-range Transboundary A i r

their

f l u x e s by a t l e a s t 30 p e r c e n t has been r a t i f i e d by 5 o f i t s

12

21

Signatories

ratifications

so

to

far. come

Both into

protocols effect.

therefore

At

the

still

need

more

f o r t y - f i r s t session o f t h e

Economic Commission f o r Europe, h e l d l a s t month i n Geneva, many d e l e g a t i o n s cited

1985

the

Helsinki

p r o t o c o l , i n p a r t i c u l a r , as b e i n g a s i g n i f i c a n t

achievement i n i n t e r n a t i o n a l e n v i r o n m e n t a l c o - o p e r a t i o n , hope I

that

further

and expressed

the

P a r t i e s t o t h e Convention would r a t i f y i t o r accede t o

L.

Governments need n o t w a i t f o r t h e e n t r y i n t o f o r c e o f t h e s e however,

protocols,

o r d e r t o t a k e implementing a c t i o n a t t h e n a t i o n a l l e v e l o r t o

in

go even f u r t h e r t h a n t h e p r o t o c o l s r e q u i r e . Ten o f t h e s i g n a t o r i e s

of

the

H e l s i n k i p r o t o c o l have a l r e a d y s t a t e d t h e i r w i l l i n g n e s s t o reduce e m i s s i o n s beyond t h e 30 p e r c e n t t a r g e t ; and s e v e r a l c o u n t r i e s have

indicated

plans

t o a c c e l e r a t e t h e t i m e - p l a n envisaged by t h e p r o t o c o l . Pending t h e financing

of

entry the

EMEP

into

force

of

the

protocol

for

the

long-term

m o n i t o r i n g programme, EMEP i s funded by v o l u n t a r y

c o n t r i b u t i o n s f r o m t h e P a r t i e s t o t h e Convention. C u r r e n t l y d a t a on a i r and precipitation

quality

from

96

stations

i n 24 c o u n t r i e s a r e r e p o r t e d t o

For example, t h i s y e a r t h e E x e c u t i v e Body w i l l r e c e i v e i n f o r m a t i o n on

EMEP.

annual transboundary f l u x e s and d e p o s i t i o n o f s u l p h u r compounds o v e r Europe f o r t h e y e a r s 1980 and 1983. It s h o u l d be

emphasized

that

the

voluntary

c o n t r i b u t i o n s f o r EMEP r e c e i v e d so f a r have been s u f f i c i e n t o n l y

financial

t o c o v e r t h e b a s i c requirements o f t h e agreed work p l a n , and a c o n s i d e r a b l y higher

level

of

f u n d i n g would be needed t o c a r r y o u t t h e f u l l programme.

Since EMEP i s expected a l s o t o p l a y an i m p o r t a n t r o l e i n t h e i m p l e m e n t a t i o n of

the

Helsinki

protocol

it

will

be

crucial

t o keep t h e measurement

a c t i v i t y and t h e model c a l c u l a t i o n s c a r r i e d o u t under t h i s programme

at

a

h i g h s t a n d a r d i n t h e coming y e a r s . Besides t h e EMEP programme ( w i t h i t s i n t e r n a t i o n a l c e n t r e s Norway

and

in

t h e USSR), t h r e e f u r t h e r i n t e r n a t i o n a l c o - o p e r a t i v e programmes

f o r m o n i t o r i n g assessment o f a i r p o l l u t i o n e f f e c t s , under t h e the

located

Executive

auspices

of

Body f o r t h e Convention, have been launched w i t h i n t h e p a s t

s i x months:

-

A i r p o l l u t i o n e f f e c t s on f o r e s t s a r e b e i n g m o n i t o r e d and initial

funding

t h e Federal R e p u b l i c o f Germany as l e a d Centre

for

assessed,

with

f r o m t h e U n i t e d N a t i o n s Environment Programme, and w i t h country;

the

Federal

Research

F o r e s t r y and F o r e s t Products i n Hamburg and t h e Czechoslovak

13

Centre f o r

the

Environment

in

Bratislava

serving

as

programme

co-

o r d i n a t i n g centres.

-

A c i d i f i c a t i o n o f r i v e r s and l a k e s i s b e i n g assessed under t h e of

Canada,

with

the

active

participation

t h e USSR, and w i t h t h e

of

Norwegian I n s t i t u t e f o r Water Research i n Oslo

leadership

providing

the

programme

centre.

-

E f f e c t s on m a t e r i a l s , i n c l u d i n g studied

under

a

programme

historic

led

by

and

Stockholm as t h e main r e s e a r c h c e n t r e , and Czechoslovakia,

the

cultural

monuments,

are

t h e Swedish C o r r o s i o n I n s t i t u t e i n four

subcentres

located

in

Federal R e p u b l i c o f Germany, Norway, and t h e U n i t e d

K i ngdom.

I n i t i a l p r o g r e s s on t h e s e been

most g r a t i f y i n g .

three

government-sponsored

programmes

has

It i l l u s t r a t e s t h e k i n d o f " m u l t i p l i e r e f f e c t " which

t h e Convention has t r i g g e r e d i n i n t e r n a t i o n a l e f f o r t s t o deal w i t h t h e a c i d rain

problem.

While

the

number

of

countries

programmes on a v o l u n t a r y b a s i s i s growing,

who

there

have

should

joined be

these

even

wider

participation. The i n i t i a l f o c u s has been on s u l p h u r d i o x i d e attention

is

being

emissions;

now

serious

g i v e n a l s o t o n i t r o g e n oxides. N i t r o g e n compounds a r e

known t o account f o r about one t h i r d o f t h e d e p o s i t i o n l o a d connected acidification,

and

are

also

a

other photo-oxidants. Following t h e establishment o f Nitrogen

Oxides

by

with

key f a c t o r i n t h e f o r m a t i o n o f ozone and a

Working

Group

on

t h e E x e c u t i v e Body f o r t h e Convention i n J u l y 1985, a

s u b s t a n t i a l amount o f i n f o r m a t i o n has been assembled by government

experts

and by c o n s u l t a n t s ; I p a r t i c u l a r l y w i s h t o acknowledge t h e s u p p o r t p r o v i d e d by t h e Government o f The Netherlands .in t h i s r e s p e c t . The "Saas-Fee D e c l a r a t i o n " adopted i n February 1986 and endorsed by

11

Governments, f u r t h e r h i g h l i g h t e d t h e problem o f a i r p o l l u t i o n f r o m n i t r o g e n o x i d e s and hydrocarbons. On t h e b a s i s

of

proposals

to

be

made

by

the

Working Group, i t i s expected t h a t t h e E x e c u t i v e Body a t i t s f o u r t h s e s s i o n i n November t h i s y e a r , w i l l be i n a

position

to

take

concrete

measures

a i m i n g a t t h e e f f i c i e n t c o n t r o l o f n i t r o g e n oxides. Measures f o r d e a l i n g w i t h t r a n s b o u n d a r y a i r p o l l u t i o n have f a r - r e a c h i n g economic

a s w e l l as t e c h n i c a l i m p l i c a t i o n s . As i s t h e case i n d e a l i n g w i t h

t e c h n i c a l problems, such as a c i d i f i c a t i o n , c o n c e r t e d a c t i o n can greater

economy

and

efficiency.

It

result

in

would seem t o be more economical t o

14

undertake

joint

pollution

control

programmes

rather

than

national

programmes alone. The ongoing already

programmes

resulted

in

a

for

implementation

lively

know-how, which i s b e g i n n i n g t o have especially

in

the

field

of

of

the

Convention

have

exchange o f t e c h n o l o g i c a l i n f o r m a t i o n and its

spin-off

in

commercial

terms,

East-West t r a d e r e l a t i o n s . With t h e gradual

t i g h t e n i n g o f e m i s s i o n s t a n d a r d s i n a l l ECE c o u n t r i e s , t h e search i s now on for

the

most

cost-effective

methods

on

pollution

encouraging t h e e x p o r t o f s p e c i a l i z e d equipment and

-

control

foreign

thereby

licensing

of

new t e c h n i q u e s . Next week we s h a l l h o l d i n Austrian

Government

-

-

Graz

at

the

kind

N i t r o g e n Oxides f r o m S t a t i o n a r y Sources. The

of

the

response

from

industry,

in

has been i m p r e s s i v e . W i t h about 200 p a r t i c i p a n t s and more t h a n

particular,

90 papers a l r e a d y r e g i s t e r e d , t h e s e seminars a r e high-level

invitation

t h e f o u r t h ECE Seminar on t h e C o n t r o l o f Sulph!ir and

rapidly

turning

into

a

m a r k e t - p l a c e f o r t e c h n o l o g i c a l i n n o v a t i o n s , where many b u s i n e s s

companies l o o k b o t h f o r t r a d e o p p o r t u n i t i e s and f o r

early

information

on

t h e t r e n d o f f u t u r e governmental r e g u l a t i o n . A i r pollution control

subjects

of

the

technology

will

ECE

forthcoming

also

Symposium

be

included

on

East-West

O p p o r t u n i t i e s and Trade Prospects, t o be h e l d i n T h e s s a l o n i k i September

1986.

After

all,

the

more

we

among

the

Business

(Greece)

in

can m o b i l i z e market f o r c e s t o

a c h i e v e o u r common e n v i r o n m e n t a l o b j e c t i v e s , t h e l e s s c o e r c i o n we

need

to

a p p l y t h r o u g h governmental i n t e r v e n t i o n . O b v i o u s l y , governmental p o l i c i e s on s t a n d a r d s w i l l c o n t i n u e t o p l a y t h e predominant

role

in

this field.

T h i s i s c l e a r l y i l l u s t r a t e d by t h e m a j o r

r e v i e w o f n a t i o n a l s t r a t e g i e s and p o l i c i e s f o r a i r p o l l u t i o n c o n t r o l , which is

currently

and t h e r e s u l t s o f which w i l l be p r e s e n t e d t o t h e

underway,

n e x t m e e t i n g o f t h e E x e c u t i v e Body i n November t h i s year. comes

to

translating

governmental

policies

and

However, when

standards

p o l l u t i o n abatement measures, we must ensure t h e a c t i v e i n v o l v e m e n t o f industries

primarily

concerned,

m a n u f a c t u r e r s o f motor v e h i c l e s . these the

namely

f o s s i l -fuel

it

i n t o actual the

power p l a n t s and t h e

A d i a l o g u e s h o u l d be m a i n t a i n e d w i t h

i n d u s t r i a l s e c t o r s , as t h e m a j o r t a r g e t s o f p o l l u t i o n c o n t r o l s under Convention

and

its

protocols,

both

with

r e g u l a t i o n s and t h e i r e f f e c t i v e i m p l e m e n t a t i o n .

respect

to

formulating

15

The p a r t i c i p a t i o n UNEP,

of

other

international

organizations,

especially

WMO and WHO i s a l s o of c r i t i c a l importance. They p r o v i d e s u b s t a n t i a l

f i n a n c i a l and t e c h n i c a l s u p p o r t t o t h e work programme c a r r i e d o u t under t h e Convention.

It

is

gratifying

to

governmental o r g a n i z a t i o n s as w e l l

n o t e t h e keen i n t e r e s t o f s e v e r a l nonin

this

work,

and

the

very

useful

c o n t a c t s which a r e t h u s m a i n t a i n e d i n areas o f common concern. The phenomenon of a c i d i f i c a t i o n and long-range a i r course,

pollution

has,

ceased t o be c o n f i n e d t o t h e ECE r e g i o n alone. A c i d d e p o s i t i o n has

been found downwind o f t h e Zambian c o p p e r b e l t , and i n s o i l samples state

of

of

Sao

Paulo

in

in

the

B r a z i l . F o r e s t s i n T h a i l a n d and t h e T a j Mahal i n

I n d i a a r e r e p o r t e d t o be t h r e a t e n e d by a i r p o l l u t i o n . The c o u n t r i e s o f o u r r e g i o n production

and

long-range

-

a f t e r p i o n e e r i n g , so t o speak,

export

of acid rain

-

the

mass

c o u l d a l s o show t h e way

towards e f f e c t i v e i n t e r n a t i o n a l p o l i c i e s f o r i t s c o n t r o l i n o t h e r

regions.

T h i s Conference can make a s i g n i f i c a n t c o n t r i b u t i o n i n t h i s regard. T h i s I n t e r n a t i o n a l Conference i s b e i n g convened a t time,

when

further

impetus

a c i d i f i c a t i o n and i t s p o l i c y i m p l i c a t i o n s . Transboundary

Air

a

most

propitious

s h o u l d be g i v e n t o programmes concerned w i t h

P o l l u t i o n provides

-

The

Convention

on

Long-range

as you j u s t s a i d M r . M i n i s t e r

framework i n which a c t i o n can be taken. The ECE w i l l c o n t i n u e t o

play

-

the its

v i t a l r o l e i n t h e i m p l e m e n t a t i o n o f t h e Convention. Mr.Minister,

D i s t i n g u i s h e d Delegates,

May I e x t e n d my v e r y b e s t wishes f o r Conference,

and

mark

the

success

of

this

important

t h e i n t e n s e i n t e r e s t which t h e ECE w i l l t a k e i n i t s

d e l i b e r a t i o n s and c o n c l u s i o n s .

T. Schneider (Editor)/Acidification and its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

19

ACIDIFICATION EFFECTS IN THE AQUATIC ENVIRONMENT

W. D I CKSON The National Environment (Sweden)

Protection Board, P.O. Box 1302, 171 25 Solna

ABSTRACT The emissions of sulfur in Europe have been reduced somewhat as compared to 10-15 years ago. This is reflected by reduced sulfate concentration in several lakes in Southern Scandinavia, but not necessarily by reduced acidity. The acid deposition still far exceeds what low buffered catchments can produce of bases. The soils are therefore under continuous degradation. Also nitrate concentration is incredsing. For both sulfur and nitrogen the yearly deposition needs to be reduced by 70-80 % in order to stop further acidification of surface waters and to avoid a coming boom from nitrate acidification. "Acidification of soil and water is a dynamic process which depends on fluxes of acidifying chemicals and on geochemical and biochemical reactions involving an exchange of protons in the whole ecosystem." (ref.1) INTRODUCTION Today it is accepted by the scientific community that atmospheric deposition of acidifying substances will affect surface waters. It is also accepted that in areas with high dry deposition of SO2 and (NH4)*S04 these substances significantly contribute to the acidification. The relations between emission, deposition and effects can be found by studying the actual pollution situation in Europe. The deposition range of acid varies from 0.1 Keq/ha in the most remote areas to 10 Keq/ha in the most polluted regions. The run off pattern of acid anio'ns very closely reflects the emission pattern. The concentration ranges from 10 w q / l in the most remote areas to above 1000 i.leq/l in the central parts. It is also accepted that in non calcareous areas the yearly weathering of basic substances (Ca, Mg, Na, K or HC03) will not increase at d great extent if acid load increases. Instead the soil or run off wdter will be acidified. This means that water acidification will be most apparent in areas of low base content, whereas soil acidification will be predominant where the soil c o n d i t i o n s dre more fdvourable. Accordingly, up till now water acidificdtion has been most obvious in rather remote areas of Europe, as Scandinavia, where the soil conditions are naturally very poor. Here yearly production from weathering is only 0.1-0.4Keq/ha

20

whereas the acid load is in the range of 1 Keq/ha. In Central Europe the gradual soil destruction is more apparent which causes increased leaching of hazardeous metals from the soil to the run off waters. But, simultaneously the alkalinities of streams and lakes have decreased during this century (ref.1). Nevertheless acidification of poorly buffered lakes in sandy regions in Central Europe took place without being noticed by scientists for a long time (ref.2). Now acidified lakes and small water bodies are observed all over Europe. In Scotland, England, Denmark, Western Germany, Eastern Germany, Poland, Czechoslovakia streams and lakes have undergone a significant degree of acidification. The freshwater acidification in the Alpine zones in Switzerland and Italy is less serious than in North Europe because of the more favourable geological environment. However, many alpine lakes and tarns are already suffering a deterioration. In Belgium and the Netherlands acidification has been proved to have taken place in poorly buffered, oligotrophic waters on mineral sandy soils, i.e. moorland pools, some small lakes and dune pools (ref.3). HISTORICAL REVIEW Perhaps the very first reports of acidification in Europe came as long ago as the early 1900s from Norwegian fisheries inspectors. Fish kills of Atlantic salmon were reported as early as in 1911 (ref.4). Several fish hatcheries had already installed limestone filters by the 1920s to treat acid hatchery water. Brown trout began disappedring from mountain lakes in the 1920s and 1930s, and, by the 1950s, barren lakes were reported from many regions in southernmost Norway. Also the salmon had essentially disappeared from several major rivers. The doubling in sulfur emissions over the 1950-1970 period resulted in an approximate doubling of the acidity in precipitation measured at the European precipitation chemistry network stations in Southern Scandinavia over the same period. During the same period, the number o f fish populations that have disappeared have increased tremendously (ref . 5 ) . In Scandinavia, Norway, Sweden and Finland some 30.000 lakes and running waters of a total length of at least 200 000 km are affected by acidification. ACIDIFICATION MOBILIZES T O X I C ALUMINIUM When the amounts of acidic anions from the atmosphere (e.g. S0,2-,N0,) leaching through the soil approaches or exceeds the leachable amounts of basic cations, high concentrations o f acidic cations ,'H( Alnf) will be found in the run off. Elevated concentrations of aluminium is therefore exported in acidic waters in areas with high inputs of acidic substances. Pronounced temporal and spatial variations in concentration of aqueous aluminium have been reported in

21

acidic surface waters as we1 1 . Pulsed inputs of NO- are typically observed 3 during snowmelt in sensitive areas (ref.6). The higher the acid load and the degree of soil acidification, the higher will the leaching of aluminium appear. In northernmost Scandinavia - the least polluted - but one of the most sensitive partsof Europe - the aluminium level does not reach IOOpg/l during snowmelt whereas Al-concentrations of 10.000ug/l are found in Central Europe at a higher degree of acid load and soil acidification. The toxicity of aluminium to fish has been known for at least 47 years. At pH 5 "the solutions remain toxic until the concentration falls to 0.07mg; which represents the lethal concentration limit for aluminium"(ref.7). Of the different forms of dissolved aluminium found in the acidic waters the inorganic fractions Al(OH)'+ and Al(OH)? appear to be most toxic. It is not possible to specify absolute llzvels of toxicity. Inve*;tigations show that Atldntic sdlmon are killed during short acidic episodes, when pH decreases and the concentrdtions of ionic aluminium incredse rapidly (ref.8). The fish kill is documented in control led fish experiments combined with continuous monitoring of pH and daily water sampling (Fig.1). During a two-week period, four episodes with pH drops from 5.9 to 5.1 coincided with increased water flow due to rainfall and snowmelt, accompanied by dilution of calcium and substantial changes in aluminium-speciation (Fig.1). The concentration of ionic A1 increased from 0 to 5 0 p g / l during the pH drops. These rapid changes in Al-speciation could be due to dissolution of previously precipitated A1 on the river bed by episodic flushing of the river from acid snowmelt and storm events. Of the three year-

!!,

Water level

.

$

6.0.

60.

2.0

I

40-

r 3.0

n

r: f

L

5.5.

3

20-

0J

5.01

+

+

2 4 ' 2 5 ' 2 6 ' 2 7 ' 2 8 ' 2 9 ' 3 0 1 1 ' 2 ' 3 ' 4 ' 5 ' 6 ' 7 ' 8 ' 9 '10'11'12.11'o November

December

Figure 1 . Variations in pH, water level, and labile aluminium (shaded area) in River Vikedalselva (southwestern Norway) Nov. 24 to Dec. 12, 1983. pH-curve is plotted on readings every second hour from a continuous pH monitor. Water levels are from 4 h readings of limnigraph records. Aluminium data are from daily samples. Times of death of salmon presmolts (I+) are indicated (+=I fish)(ref.8).

classes of saymon (eggs to presmolts) only presrnolts died, illustrating the higher sensitivity of salmon during smoltification (ref.9). Continuous monitoring of water chemistry and fish behaviour in waters subjected to acid episodes are considered a key to the understanding of biological responses to the acidification Drocess. EFFECTS OF ACIDIFICATION ON PRIMARY PRODUCTION Phytoplankton Most acid lakes have been oligotrophicated as a result of increased aluminium levels. An example i s given in Fig. 2 illustrating the grddudl acidification along with increased aluminium- and decreased phosphourus levels ( a 1000 hectare.lake in Southwestern Sweden. The lake was limed at the fall of 1981. 1982-1985 pH raised to 6.5-7, the aluminium level was reduced to 30,ug/l and the phosphorus doubled to 4,ug/1 (ref.11)). PH

I

I -5.9

100

5j 10

-5.6 -5.3

- 5.0

Fig. 2. pH and levels of aluminium and total phosphorus in Lake Ommern 1974-81, Sweden (August values). Strongly acidified lakes generally have hiqh levels of metals. The toxicity of these depends on the pH-value and concentration of humic compounds. The effect of aluminium is strongest at pH 5.2-5.8 whereas most other metals are more toxic near neutral pH-values (Table 1). According to the levels in the lakes and the toxic levels observed in biotests aluminium is probably the single most toxic metal in the acid environemnt. The visible effect of aluminium on algae may be enlarged cells,contorted cells and destroyed cell membranes. At a raised aluminium level ( > 200 Pg/l) the chloroplasts are destroyed (ref.70).

23

TABLE 1 Monoraphidium - - - - - - - -griffithi;. Percentage growth reduction at the pH-values 4.8 5.5 and 6.5 at selected concentrations of manganese, aluminium, copper, zinc and cadmium (ref.11)). I

PH Mn 2000.,ug/l A1 150 "

cu 5 Zn 250 Cd 5 Mn + Cu

4.8

0 0 'I 0 I' 0 " 0 + Z n + Cd 0

5.5

0 69 0 8 0

0

6.5 11 0

48 67 36 62

Macrophytes A strong development of Juncus bulbosus and Sphagnum are reported from acidified lakes in Scandinavia. Investigations in the Netherlands show that more thdn 80 % of all naturally poorly buffered pools and lakes in heathland areas hdve been strongly acidified during the last decades. The pH-value is at present on an average of 3.8. In most cases the original vegetation has been replaced by submerged Juncus bulbosus or Sphagnum species. On these locations the C02 levels in the soil solution and the water layer have strongly increased. Initial acidification of water leads to luxurious growth of these plants as a result of increased carbon dioxide and ammonium levels in the water layer (ref. 12). The yearly production of Sphagnum and Juncus far exceeds the original of Lobelia, Isoetes and Littorella which are now being overgrown. As the prodcution of Sphagnum is continuously accumulating dnd the decomposition of organic material is strongly reduced in the acid environment, the life length of most European low buffered and shallow lakes and ponds i s now drastically shortened. Within a century many o f them will be just swamps. CONCLUSIONS ABOUT ACIDIFICATION EFFECTS ON AQUATIC ECOSYSTEMS Progressive research during the last 20 years has revealed the deep influence from acidifying emissions on aquatic ecosystems. In almost whole Europe lakes and streams are exposed to increasing concentrations of acids or metals like aluminium leaching from the soil. The effects are found on all trophic levels. Natural reserves and national parks are threatened or already destroyed and cannot fullfill their purposes to save and keep the original fauna and flora for coming generations. EFFECTS OF REDUCED EMISSIONS OF SULFUR, PROGNOSIS Severdl attempts have been made to make models and prognoses of the effects from reduced emissions on aqudtic chemistry and biology,

24 There is a strong relationship between sulfur emission, deposition, sulfur in run off dnd loss of alkalinity. Therefore reduced emissions have to result in increased alkalinity of the surface waters. The question still open is the time scale involved including the effects of accumulated soil acidification. By applying empirical data and models it is possible to calculate the effects of different emission reductions.0ne example can be given. The effects of a 50 percent reduction in deposition on the pH of two rivers in southern Norway that receive acid precipitation have been estimated. Figure 3 shows the estimated "preacidification" pH-values (pHO), present pH-values (pHt), dnd pH-values at 50 percent lower sulfate concentrations ( P H - ~ ~ ) For . River Mandalselva, a 50 percent reduction in sulfur deposition does not appear to keep the pH dbove criticdl levels for fish (pH>5.0), while River Nidelva would offer the fish acceptable conditions. River Mandalselvd was subjected to acid episodes as early as the 1930s, and the salmon catch started to decline in the 1920s. The anthropogenic emissions of sulfur in the 1925-1950 period were fairly constant, at a level about half of those emitted today. Thus, Figure 3 indicates that the present-day water chemistry can be used to predict to which level the sulfate concentration must be reduced to obtain a given water quality (ref.5). 65

River Mandalselva

I

4 ' O

Jan

Feb Mar

Apr

May

Jun

Jul

Aup

Scp Ocl NOW DOC

Fig. 3. Variations in present pH (pHt), "past" pH (pH ) and pH at 50 percent lower sulfate load (pH 50) in the rivers Mandalselva 2nd Nidelva in southernare estimated using accepted principles of the relamost Norway. pHO and pR tionships between sulfur5$eposition and sulfate concentration 'n run off and a slight reduced leaching of Ca+Mg (F-factor 0.2) at reduced S o t - .

It has been proposed that emissions of sulfur in Europe be reduced 30 percent by 1993. Using the approach outlined with relationships between deposition and run off sulfur, it can be predicted that more than 20 % of the lakes now experiencing fisheries problems in Southern Norway should be able to support fish (ref. 13).

25

On the other hand, following the criterium that at least 80 % of the lakes in Southwestern Sweden should have a summer alkalinity, the present deposition level has to be reduced by 70-80 % in that area (ref.14). EFFECTS FROM ALREADY REDUCED SULFUR DEPOSITION The last decade*s sulfur emissions in Europe have been reduced b y - 20 %. Local emissions in Sweden hdve reduced by-60 % since 1970. Also sulfur deposition in precipitation has been reduced byd20 % in South Scandinavia (ref.15). The investigations performed in lakes in Southwestern Sweden indicate a reduced sulfur content in lake waters by on the average 20 %. Often the reduction is coupled to an increased pH-value, as described by (ref.16). Some comparisons of different lake water quality for the years 1947-52, 1976 and 1983 are given in Table 2 as mean values from some very dilute lakes, and some rather lime rich lakes. The naturally most low buffered waters were still very acid 1983. The well buffered lakes contain natural limestone (shells) and a reduced sulfur deposition will influence the weathering of limestone. The lake category between these extremes, is the one which is nowadays normally limed by "anthropogenic limestone" payed by the government. These lakes also show a reduced sulfur concentration by on the average 20 % (ref.17). TABLE 2 Long term water quality changes in some lakes of Southwestern Sweden (ref.17) meq/l (Ca t MgX and SO,X values mean n o n marine). Well buffered ( n = 6 ) 1947-52 1974-79 1983

Ca+MgX Alk SO: 0.30 0.29 0.56 0.24 0.31 0.45 0.20 0.25

Low buffered (n=5) pH 6.9 7.0

7.1

Ca+MgX 0.04 0.11 0.12

Alk 0.01 0 0

SO:

pH 5.3 0.22 4.3 0.21 4.6

Concerning the time delay between sulfur decrease and pH-increase, one has to remember that even the present acid loadsin Southern Scandinavia (1-1.5 keqlha-y: far exceed what most o f the catchments can produce of bases (0.1-0.4keq/ha.y), and that accumulated soil acidification is a present fact that will delay the stream water restauration. CRITICAL LOAD FOR NITROGEN ON SURFACE WATERS In contrast to sulfur the atmospheric nitrogen loading does not show declining trends. I n Central Europe the yearly deposition o f nitrogen compounds (NH4-N, N03-N and Org-N) is in the order o f 40-80 kg N per hectare, in Southern Sweden 20-30 k g N whereas in Northern Scandinavia total deposition is less than

26 5 kg. However, in most of Europe still 70-90 % of the deposited nitrogen compounds are stored in the soil. Therefore the accumulation will be considerable after some decades. The potential effects of the ongoing accumulation and leaching to the waters are discussed frequently and apparently in large areas this increased leaching has already begun. In soils of low base saturation the ledching has to be in the form of nitric acid and a urninium nitrate. I n River Morrumsin (90 % of catchment area fores ed) in Southern Sweden the nitrate concentration has increased from less than 00,~1gN03-N/1 in 1965 to 300,ug/l 1985 (Figure 4).

SALMON RIVER MQRRUMSAN

NO3-N

Southern Sweden

PS/l

Prognosis based on knowledge and judgmeni

700

x-

;

PH 6.3

(lime dosersl Al=lmg/l

(all killed1

600

I

X

.'/ I

5 00

r.0.68

X

LOO

300

1 SO*/. killed of newly hatched)

200

100

50 l

I

1

1965 70 75

I

Z

I

I

I

85 9 0 95 2001 year mv-apr

80

Fig. 4. The nitrate levels during winter season (nov-apr) has about trippled during the period 1965 to 1985. During the last winters the mortality of newly hatched salmon fry in the Morrum Hatchery has been about 50 %, although pH is above 6 . But the aluminium level is about 0.2 mg/l, which may cause problems during cold water season. A speculative prognosis for the year 2001 could give a 100 % mortality nitrate increases to 700,ug/l and aluminium to 0.5-1 mg/l (ref.17). A similar increase is shown in lakes from southern Sweden not effected by agriculture or forest fertilizers. Deep oligotrophic lakes now have high nitrate content even during late summer. During the last 10-20 years the nitrate concentration has increased by 50-100 %. The high nitrate level also indicates a severe

27

phosphorus deficiency, which is connected to acidification as a decreased leaching of phosphorus in the acid environment. To set up a critical load for the long term acceptable deposition of nitrogen as for sulfur is certainly a difficult task. Concerning the direct acidification effects from nitric acid during spates perhaps the same critical acidity as for sulfur in snow could be used i.e. pH 4 . 6 - 4 . 8 . But as at least half of nitrogen deposits as neutral but strongly acidifying ammonium the critical load should rather be expressed in terms of keq/ha. Increasing leaching of nitrate to surface waters are found in Scandinavia where total deposition exceeds 1 keq/ha (15 kg N/ha). This figure seems to be a rather conservative one, but still far less than the present deposition amount from the more polluted atmosphere further south. NITROGEN AS EUTROPHICATION RISK Concerning eutrophication even lower values should be needed if the natural ecosystem will persist. A total leaching of inorganic nitrogen of less than 0.1-0.2kg per hectare is only reached where deposition of nitrogen is below 5 kg per hectare (i.e. about 2 kg as wet deposition). As for sulfur this level is exceeded by 5-10 times in Southern Scandinavia and Central Europe. Recently, the eutrophication of the Baltic has focussed on the nitrogen deposition from the atmosphere. Available figures indicate that about one third of the nitrogen input comes as atmospheric deposition directly onto the Baltic surface. This amount plays a significant role in the speeding up of the Baltic eutrophication. The present load on the Baltic from the atmosphere is estimated to 10 kg N/ha.y (ref.18). The critical load therefore should be set to a figure less than this. LIMING OPERATION AS ALTERNATIVES In attempts to combat acidification of lakes, streams or soils several national liming programmes have started . In Sweden, more than 4 000 lakes have been limed over the last few years. W c h of the cost is met by the State: this year 110 million SEK is being spent on liming and follow up. The biological effects are positive, althoug’n leaching of metals cannot be stopped from the soil as long as only waters are treated ref.19). The most commonly used materials are limestone powders of fractions 0-0.5 or 0-0.2mm. These seem to be the most cost effective for lakes. By liming strategically along shores and on wetlands it is possible to retain alkalinity for several years even in lakes with very short retention times. Liming running waters is more complicated than lakes as the dosing machines have to operate during high flows and low temperatures. Several high as well as

28

low technological machines have been developed to combat these problems. But the ongoing acidification will continue unless land is limed or the atmospheric acid load is decreased. Liming nationalparks and reserves in remote mountain areas is not a very attractive way to combat the present acidification. A preferable way is further eciission reductions. Most waters would become healthy if the total acid load from atmosphere gets lower than 0.3 keq/ha (0.5 g sulfur per m 2')and year. For the most sensitive waters the load has to be even less than 0.2 keq/ha (0.3 g S/m 2) . In southern Scandinavia the actual load is 1.3 keq/ha (2 g S/m 2 ) and in Central Europe 3-7 keq/ha (5-109 S/rn2).

REFERENCES 1 T . Paces, Nature, 315 (1985), 31-36. 2 C. Steinberg, 0. Krause-Dellin, R. Morwald, W. Hofmuth, R. Meier, S. Pauthner and K. Arzet, Seenversauerung in Mitteleuropa - Nachweis und Aspekte zur Geochemie; des 121,Seminar des F.G.U. Berlin, Mai (1985). 19 pp. 3. J.F.M. Geelen and R.S.E.W. Leuven, Impact of acidification on phytoplankton and zooplankton communities. Experientia (1986) (acc. for. publ.). 4. Huitfeldt-Kaas H, Norsk Jaeger- og Fiskefor. tidskrift (1920), 37-44. 5. A. Henriksen, Acid Rain and the European Situation World Angling Resources and Challenges (1985), 1 1 p. 6 C. Driscoll, Env. Health. Perspectives, 6 3 (1985), 93-104. 7 J.R. Erichsen Jones; J.Exp. Biol., 16 (19391, 425-437. 8 A. Henriksen, O.K. Skogheim and 6.0. Rosseland, Vatten 40 (1984), 255-260. 9 6.0. Rosseland and O.K. Skogheim, Rep. Inst. Freshw. Res., Drottningholm 61 (1984), 186-194. 10 E. Hornstrom and C. Ekstrom, pH, narings- och aluminiumeffekter p% plankton i vastkustsjoar, SNV PM 1704 (1983), Solna, 124 pp. 1 1 E. Hornstrom and C.Ekstrom, Acidification and Liming Effects on Phyto- and Zooplankton in some Swedish West Coast Lakes. Rapport 1864 (1986), 108 pp. 12 J.G.M. Roelofs, Effects of atmospheric sulphur and nitrogen deposition on aquatic and terrestrial heathland vegetation. Experientia (1986) (acc. for pub I.). 13 R.F. Wright and A. Henriksen, Nature, 305 (1983), 422-424. 14 J. Kamari, Critical deposition limits for surface waters assessed by a processoriented model. For BESK pubiication (?986), 15 pp. 15 H. Rodhe and L . Granat, Atm. Env. 18 (1984),2627-2639. 16 C. Forsberg, G. Morling and R.G. Wetzel,Ambio, 14 (1985), 164-166. 17 Data from National Environment Protection Board, Solna (1985-1986). 18 R. Soderlund, Deposition estimates to the Baltic based on reported data 1983/84. Baltic Marine Environment - Helsinki Commission. Neubrandenburg 5-9 May 1986. 19 W. Oickson, Vatten. 39, (1983), 400-404.

23

T. Schneider (Editor)/Acidification and its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam

Printed in The Netherlands

~

EFFECTS OF ACIDIFICATION ON FORESTS AN0 NATURAL VEGETATION, WILD ANIMALS AND INSECTS B.A.

MOLSKI and W. DMUCHOWSKI

B o t a n i c a l Garden o f t h e P o l i s h Academy o f Sciences, s k r . 84,

02 973 Warszawa 34 ( P o l a n d ) ABSTRACT The d y i n g - f o r e s t syndrom o c c u p i e s s c i e n t i s t s and f o r e s t e r s i n Europe.

It

f a c t o r (SO involved

is

Central

g e n e r a l l y agreed t h a t t h e atmospheric p o l l u t i o n i s a m a j o r

NO , ozone) c a u s i n g t h e damage. However, t h e mechanisms 2' x i n f o r e s t s d e t e r i o r a t i o n and e s p e c i a l l y t h e methods o f e v a l u a t i o n

o f t h e s e damages a r e scientists.

The

not

completely

evaluation

of

understood

dry

and

agreed

t h e i r f o r e s t growth d e t e r i o r a t i o n e f f e c t s s h o u l d be based on composition

leaves

of

(pollutants

upon

among

and wet d e p o s i t i o n o f p o l l u t a n t s and and

the

chemical

n u t r i e n t s ) , growth i n c r e m e n t and

l i t t e r decompos t i o n . INTRODUCTION A c i d i f i c a t on o f environment means "wet" a c i d i f y i n g d e p o s i t i o n i n form

of

snow and fog, and " d r y " i n t h e f o r m o f gases and d u s t . The

rain,

.

atmosphere a r e H S, SO -SO and NO 2 2 4 X y e a r t o t h e a i r on a w o r l d w i d e b a s i s by n a t u r a l

main a c i d i f y i n g compounds i n t h e Emisions

of

the

sulphur

per

processes ( v o l c a n i c a c t i v i t i e s , f i r e s , metabolism o f organisms and o t h e r s ) 6 6 6 a r e much l a r g e r (150 t o 470 t o n s o f S ) t h a n t h e human a c t i v i t i e s ( 7 0 6 284 t o n s o f S ) , b u t t h e emissions caused by man o c c u r o n l y over

-

industrialized

regions

covering

less

t h a n 5% o f t h e e a r t h ' s s u r f a c e . I n

t h e s e r e g i o n s (Europe, E a s t e r n N o r t h America, Japan) man-made exceed 2).

the

natural

Emission of NO

X

S

emissions

emissions by a f a c t o r o f 5 t o 20 ( r e f . 1-4) ( s e e F i g . a r i s e s b o t h from t h e

nitrogen

in

t h e and a h i g h

f i x a t i o n o f atmospheric n i t r o g e n . The man-made world e m i s s i o n 6 6 N a t u r a l processes o f n i t r o g e n i s about 75 -100 t o n s p e r y e a r ( r e f . 4). 6' depending on v a r i o u s sources o f e s t i m a t i o n ( r e f 1-4), c o n t r i b u t e of 80 6 6 k 270 p e r y e a r i n t h e f o r m o f NH and o f 60 -430 t o n s i n t h e form o f 3 n i t r a t e from NO ( r e f . 3).

temperature

X

30

Very h i g h e m i s s i o n s o f S and N with

many

local

sources

of

within

emissions

large

industrialized

overlapping

i n f l u e n c e on v e g e t a t i o n produce a v e r y b i g area l e a d i n g t o t h e of

regions

w i t h t h e i r zones o f destruction

f o r e s t s ( s e e Tab. 1) and m a j o r changes i n t h e v e g e t a t i o n c o m p o s i t i o n on

wide areas i n C e n t r a l Europe (see F i g . 1). However, even i n t h e s e areas one can

find

wind

places

velocity,

vegetation,

w i t h a s m a l l e r d e p o s i t i o n o f p o l l u t a n t s due t o t h e l o c a l precipitation

etc.

In

areas

and

of

the

possibility

scattered

of

relatively

accumulation small

sources

by of

emission, as f o r example i n Spain, N o r t h e r n F i n l a n d and N o r t h e r n Sweden t h e and NO i s o n l y l o c a l and depends m a i n l y on a s m a l l e r 2 X d e p o s i t i o n up t o s e v e r a l k i l o m e t r e s f r o m t h e source o f emission. dispersion

of

SO

The t o t a l d e p o s i t i o n o f s u l p h u r , d r y and wet, i s v e r y emission

source.

importance. In hours

up

to

In

high

near

the

more remote areas t h e wet d e p o s i t i o n assumes g r e a t e r

d r y d e p o s i t i o n (SO ) atmospheric l i f e t i m e i s f r o m a few 2 two days and t h e mean t r a n s p o r t d i s t a n c e up t o a few hunderd has 3 t o 5 4 t h e mean t r a n s p o r t d i s t a n c e i s about a thousand

k i l o m e t r e s , d i m i n i s h i n g r a p i d l y w i t h d i s t a n c e . SO

days

lifetime

km o r more.

and

The most damaging e f f e c t s o f a i r background

pollution

is

pollution

are

in

areas

from

sources

of

emission

a c c u m u l a t i o n of p o l l u t a n t s . needles

high

transboundary

air

Czechoslovakia and t h e German Democratic R e p u b l i c produces

h i g h a c c u t e damages t o f o r e s t s i n south-western local

a

a

e n l a r g e d by l o c a l sources o f p o l l u t i o n , which i s

demonstrated b y F i g . 3 r e p r e s e n t i n g Poland, where a h i g h pollution

where

of

also The

contribute map

of

Poland.

Nevertheless

the

intensively, increasing the

sulphur

accumulation

i n Poland suggest t h a t t h e t r a n s p o r t i s n o t so remote.

in

pine

It seems t o

be i n c o n t r a s t t o t h e e v a l u t i o n done by m e t e o r o l o g i c a l models o f p o l l u t a n t s diffusion

in

the

world.

It

may

also

be

possible

a c c u m u l a t i o n by v e g e t a t i o n decreases r a p i d l y w i t h source.

However,

only

a

better

pollutants from

the

and

Northern

Europe,

u n d e r s t a n d i n g o f t r a n s p o r t a t i o n and accumulation.

In

Europe more t h a n 6 m i l i o n ha o f f o r e s t a r e damaged, and about 1 m i l i o n

ha

of

bring

that

distance

a mapping o f a i r p o l l u t a n t s a c c u m u l a t i o n i n f o r e s t

t r e e s i n a l a r g e area, such as t h e whole o f C e n t r a l may

the

t h a t i s s e r i o u s l y damaged (see Tab. 1 and 2). There i s no doubt t h a t a t

l e a s t 1 m i l i o n ha o f s e r i o u s l y damaged f o r e s t i s caused by at

least

as

the

air

pollution,

p r i m a r y cause o f d e c l i n e . W i t h o u t a i r p o l l u t i o n and i t s

wide d i s p e r s i o n , as w e l l as i t s d i r e c t and i n d i r e c t i n f l u e n c e ,

the

recent

31

forest

damage

could

not

have

occured

in

t h e p r e s e n t form and e x t e n t .

N e v e r t h e l e s s n o t a l l s c i e n t i f i c a l l y p r o v e n evidence i n d i c a t e s t h a t t h e pollutants

are

o f damaged f o r e s t s a r e e f f e c t e d by drought, fungal But t h e wide d i s p e r s i o n o f SO

due t o h i g h

smoke

steadily

temperatures increasing

contamination

NO

stacks, in

from

X

furnaces

negative

factor

diseases,

insects

and to

ozon f o r m a t i o n , a r e no doubt a vegetation,

soil

and

water

l e a d i n g t o t o x i c l e v e l s o f accumulation. The damage process

i s d i f f i c u l t t o study e m p i r i c a l l y , since several p o l l u t a n t s are the

and

accumulated f r o m y e a r t o y e a r , 2’ growing r o a d t r a f f i c and h i g h e r

windbreaks. combustion

air

c a u s i n g t h e most o f t h e p r e s e n t f o r e s t damages. Many areas

active

at

same t i m e l e a d i n g t o s y n e r g i s t i c e f f e c t s . The r e c e n t widespread

i n c r e a s i n g f o r e s t damages a r e presumed t o be caused by factors,

biotic,

abiotic,

climatic,

importance v a r i e s

according

to

precipitation

the

surface

on

leaf

site of

a

complex

man-made,

etc.

whose

conditions.

The

effect

trees

and

and set

of

relative of

acid

t h e s o i l causing t h e

l e a c h i n g o f n u t r i e n t s i s e s p e c i a l l y dangerous. There a r e s e v e r a l hypotheses about t h e f o r e s t d e c l i n e i n acidification

-

of

the

deposition

of

acidic

accelerated

11)

as

a

and a c i d i f y i n g substances from t h e

atmosphere l e a d i n g t o i n c r e a s e d c o n c e n t r a t i o n s o f s o l u b l e Aluminium

The

aluminium t o x i c i t y h y p o t h e s i s developed by U r l i c h ( r e f .

holds t h a t t h e n a t u r a l a c i d i f i c a t i o n o f f o r e s t s o i l s i s result

Europe:

aluminium

ions.

t o x i c i t y r e s u l t s i n n e c r o s i s o f f i n e r o o t s and a decrease i n t h e

w a t e r uptake and d e a t h o f t h e t r e e s , p a r t i c u l a r l y d u r i n g d r o u g h t p e r i o d s . The ozone h y p o t h e s i s based on f i e l d o b s e r v a t i o n s

of

foliar

symptoms

and measurements o f ozone c o n c e n t r a t i o n s as w e l l as on c o n t r o l l e d exposures o f s e e d l i n g s o f v a r i o u s t r e e s p e c i e s presumes t h a t ozone damage

of

leaves,

weakening o f

leads

to

direct

c e l l membranes and n u t r i e n t s t o be l o s t

f r o m damaged c e l s . The aluminium d e f i c i e n c y h y p o t h e s i s based on so 1 and f o l i a r analyses

in

high

elevation

spruce

stands

shows

an

chemical

extreme magnesi um

d e f i c i e n c y i n t r e e s and b i g s u p p l i e s o f n i t r o g e n and c a l c i u m l e a d i n g t o t h e d i s t u r b a n c e o f t h e s e t r e e s growths ( r e f . 12). The ammonium h y p o t h e s i s ( r e f . 1 3 ) suggests t h a t a in

soil

and

plants

due

to

the

nitrogen

h i g h amounts o f atmospheric f a l l o u t i s

c a u s i n g f o r m a t i o n o f c e l l s w i t h l a r g e volumes t h a t a r e e a s i l y wind, d r o u g h t and p a r a s i t e s .

build-up

attacked

by

32

The g e n e r a l carbohydrate

stress

hypothesis

economy

(ref.

disturbance

due

12)

regards

to

a

the

decrease

whole-plant in

the

net

p h o t o s y n t h e t i c p r o d u c t i o n and t h e a s s o c i a t e d d i v e r s i o n o f c a r b o h y d r a t e s less

mobile

and

to

p o t e n t i a l l y t o x i c secondary substances l e a d i n g t o a p o o r

development o f f i n e r o o t s and m y c o r r h i z a e and t o f o l i a r d e c l i n e , t o be

the

major e f f e c t o f a i r p o l l u t i o n . One more h y p o t h e s i s as t o t h e e x p l a n a t i o n o f t r e e s d e a t h pollution

may be added

-

due

to

air

t h e t h e o r y o f a s u p r e s s i o n o f t h e s y m p l i s t i c ways

o f t r a n s l o c a t i o n o f c a r b o h y d r a t e s from l e a v e s t o r o o t s . A decrease

in

the

c a r b o h y d r a t e p r o d u c t i o n and a r e d u c t i o n o f t h e r a d i a l growth o f t r e e s cause f i r s t o f a l l a d i s t u r b a n c e i n t h e phloem growth elements

function

14.).

(ref.

Sieve

tube

o n l y f o r a few months and t o ensure permanent s u p p l y o f

o r g a n i c substances f r o m t h e

tree

crown

to

roots,

there

has

to

be

a

c o n t i n u o u s growth o f t h e new l a y e r s o f phloem t h r o u g h t h e whole t r e e t r u n k . Any decrease i n t h i s pathway l e a d s t o t h e s t a r v a t i o n including

the

and

mycorrhizic fungi.

the

root

system

g r o w t h o f f i n e r o o t s which c o n d i t i o n t h e p r o p e r

continuous

uptake o f w a t e r

of

mineral

nutrients

as

well

as

the

starvation

I n t h i s way a decrease i n t h e f o l i a r f u n c t i o n due t o a i r

p o l l u t i o n causes a decrease i n t h e r o o t s f u n c t i o n as t o w a t e r uptake. reduction

of

water

uptake

A

tree

without

b o t t l e o f water

-

and

the

leads

to

activities

of

t h e tree.

growth

A v e r y common symptom o f abundant

f o r m a t i o n o f a d v e n t i t i o u s s h o o t s on t h e upper s i d e s o f branches l o c a t e d near

the

ground

as p o s s i b l e i n f i r s ,

as

p i n e s and spruces i n p o l l u t e d areas

serves t w o f o l d : i n l o w e r p a r t s o f t h e f o r e s t t h e r e i s a pollutants'

of

f i n e r o o t s behaves as a p i e c e o f branch p u t i n a

a mechanical w a t e r u p t a k e can n o t e n s u r e a normal death

This

has d e l e t e r i o u s e f f e c t on t h e crowns f u n c t i o n

l e a d i n g f i n a l l y t o a f u r t h e r decrease i n t h e p h o t o s y n t h e t i c leaves.

of

much

smaller

air

a c c u m u l a t i o n i n needles due t o t h e decrease o f wind speed, and

t h e t r a n s l o c a t i o n way f r o m l e a v e s t o r o o t s i s shortened, f a c i l i t a t i n g s i e v e tube's formation. The t h e o r y o f suppression contributes

of

the symplistic

way

of

translocation

a l s o t o t h e explanation o f t h e very h i g h s u s c e p t i b i l i t y o f f i r

t o a i r p o l l u t i o n , s i n c e t h e f i r phloem s i e v e t u b e s a r e t h e most s h o r t - l i v e d and o n l y a few l a y e r s o f phloem c e l l s a r e formed p e r y e a r ( r e f . 1 5 and 16). It a l s o e x p l a i n s why t h e o l d e r and t a l l e r t r e e s a r e

pollution

t h a n t h e young and s m a l l ones

-

more

damaged

by

air

i n young t r e e s t h e t r a n s l o c a t i o n

33

from

r o o t s t o l e a v e s i s much s h o r t e r t h a n i n o l d ones.

Table 2 i l l u s t r a t e s

f o r e s t t r e e damages broken down t o t r e e s p e c i e s i n s e l l e c t e d c o u n t r i e s f r o m which such d a t a were a v a i l a b l e . genera

in

The

table

represents

seven

species

f o u r c o u n t r i e s and groups o f s p e c i e s i n t w o c o u n t r i e s . The d a t a

indicate that, coniferous

although

trees

are

there

more

are

differences

susceptible

in

seperate

countries,

t h a n broadleaved t r e e s , and t h a t

fir

Abies a l b a i s always t h e most s u s c e p t i b l e t r e e species. S i l v e r alba

Mill.)

is

(Abies

one o f t h e most v a l u a b l e f o r e s t t r e e s i n m i d d l e - e l e v a t i o n

mountain ranges i n C e n t r a l Europe. A been

or

periodically

appearing

disease

has

known s i n c e t h e b e g i n n i n g o f t h e l a s t c e n t u r y , b u t t h e p r e s e n t e x t e n t

o f t h e d e c l i n e i s so wide t h a t i n many p a r t s o f Europe t h i s s p e c i e s w i l l be totally

as a f o r e s t t r e e . The t a l l , above 60-80 y e a r s o l d , t r e e s a r e

lost

a f f e c t e d more s e r i o u s l y t h a n reconstruction

the

younger

ones.

Studies

of

pollen

and

18) i n d i c a t e

o f Abies movement i n t h e l a s t 5000 y e a r s ( r e f .

a c o n t i n u o u s o s c i l l a t i o n o f t h e area o f d i s t r i b u t i o n o f t h i s species and migration

towards

the

a

n o r t h o r t h e south. The p r e s e n t d e c l i n e may be t h e

n e x t "wave" towards t h e south. But t h e r e i s

no

doubt

that

man-made

air

p o l l u t i o n i s one o f t h e m a j o r f a c t o r s o f t h e disappearance o f t h e species. Pines and spruces, i n Europe, as w e l l as i n

the

USA

among t h e most s u f f e r i n g s p e c i e s f o r t h e l a s t 20 years.

(ref.

19)

are

D u r i n g t h e l a s t few

y e a r s t h e r e i s i n c r e a s i n g damage t o broadleaved species, such as oak, beech and

sycamore

maple.

Species

of

lorch

and

birch

so f a r t h e most

are

r e s i s t a n t t o a i r p o l l u t i o n , however w i t h heavy p o l l u t i o n t h e y e a r l y l e a f f a l l and a d i s c o r d e r o f branching.

and i n t e n s i v e r e s e a r c h o f t h e USA and Canada absorbs n o t opinion,

but

also

the

foresters

and

scientist.

e x p l a n a t i o n s e x i s t as t o why t h e damage expands. natural etc.,

causes

of

forests'

suffer

from

The f o r e s t d e c l i n e i n Europe

The

only lot

A

the of

public

different

controversy

between

d e c l i n e such as diseases, i n s e c t s , droughts,

as p r i m a r y s t r e s s e s and a i r p o l l u t i o n , may be s o l v e d

by

a

chemical

a n a l y s i s o f 1e a f c o n t e n t . Any o f t h e elements p r e s e n t i n t h e t i s s u e o f a p l a n t of

as

constituents

o r g a n i c m o l e c u l e s , o r as i o n i c forms or d e p o s i t s o f i n s o l u b l e s a l t , may

be i n d e f i c i e n c y , abundance o r a c c u m u l a t i o n i n p l a n t s level.

There

may

reach

and t h e i r a c c u m u l a t i o n i n leaves. F i g . 4 r e p r e s e n t s s t u d i e s o f t h e content

in

a

toxic

i s a c l o s e r e l a t i o n s h i p between c o n t e n t o f p o l l u t a n t s i n a i r sulphur

p i n e needles i n Poland. It i l l u s t r a t e s t h e g r e a t d i f f e r e n c e i n

34

s u l p h u r c o n t e n t between p i n e grown i n ones.

It

heavily

polluted

proves t h e usefulness o f scotch p i n e (Pinus s i l v e s t r i s

clean

areas

and

L.) as a n

i n d i c a t o r and an accumulator o f environmental p o l l u t i o n . The p i n e served f o r c o n s t r u c t i n g

the

map

of

pollution

for

Poland

p r e s e n t e d i n F i g . 1 and F i g . 2. The chemical information

composition

of

leaves

(needles)

because o f n u t r i e n t s ' a v a i l a b i l i t y . Potassium upland

may

valuable

deficiency

in

o r g a n i c s o i l s i n B r i t a i n caused a y e l l o w i n g o f needles ( r e f . 6.)

In

West Germany t h e y e l l o w i n g o f o l d e r needles concentrations.

Growth-limiting

or is

nutrient

nitrogen connected

tree

species

with

magnesium

are

not

adequatly

growth

of

different

levels

documented; s t u d i e s o f a dose-response c u r v e f o r t h e forest

bring

about s t a n d s ' d e c l i n e n o t o n l y because o f p o l l u t a n t s , b u t a l s o

a r e needed, which means e x p e r i m e n t a t i o n s w i t h a wide

range o f n u t r i e n t s and p o l 1 u t a n t s . An e x t e n s i v e f o l i a r a n a l y s i s r e l a t e d

to

a i r p o l l u t i o n and a s o i l a n a l y s i s may a l s o c o n t r i b u t e i m p o r t a n t i n f o r m a t i o n r e l a t e d t o t h e u n d e r s t a n d i n g o f t h e f o r e s t d e c l i n e . Fig. 5 composition

of

the

fourteen

most

represents

i m p o r t a n t elements i n p i n e needles i n

f a i r l y c l e a n and h e a v i l y p o l l u t e d areas. However one i m p o r t a n t to

be

observed

-

the

factor

has

t h e c o l l e c t i o n o f t h e f o l i a r m a t e r i a l s has t o t a k e i n t o

c o n s i d e r a t i o n t h e t i m e o f t h e growing p e r i o d and t h e p a r t i c u l a r t u r n o v e r o f elements

by

p l a n t s i n t h a t p a r t i c u l a r t i m e . The second p a r t o f t h e w i n t e r

seems t o be b e s t because a t t h i s pollutants,

and

all

other

time

there

elements

are

is

the

not

higest

in

any

content

of

physiological

transformation. Any assessment o f f o r e s t d e c l i n e growth

is

difficult

without

analyses

of

and y i e l d o f wood and t h e s e must be based on l o n g t e r m s t u d i e s o f a t

l e a s t 5-10 y e a r s . The assesment may be made on t h e b a s i s o f t r e e r i n g cores

analyses

of

the

o f sample t r e e s on permanent t r i a l p l o t s , as w e l l as on t h e b a s i s o f

p e r i o d i c measurements o f s t a n d s on permanent t r i a l p l o t s w i t h c o n s i d e r a t i o n to

a l l t r e e s removed f r o m t h e s t a n d between t h e measurement p e r i o d s . C l e a r

relationships increment

were

reduction.

noticed In

the

between

the

extent

northeastern

U.S.

of

needle

losses

and

(New York, Vermont,

Hampshire and Maine) a s t u d y of increment c o r e s from 3000 r e d spruce

New

trees

showed t h a t t h e r e d u c t i o n i n g r o w t h r a t e s began around 1960. I n t h e 1980 as t h e growth r a t e i s from 13% t o 40% l e s s t h a n i t was i n t h e

highest

growth

35

year

1960. I n t h e s o u t h e a s t e r n U.S.

(Georgia, South and N o r t h C a r o l i n a and

V i r g i n i a ) t h e d i a m e t e r growth r a t e s o f l o b l o l l y , s h o r t l e a f and s l a s h

pines

have decreased by 20% t o 39% o v e r t h e p a s t 20 y e a r s ( r e f . 6 ) . These changes i n growth r a t e s do n o t appear t o be r e l a t e d t o s t a n d age o r d e n s i t y . Experiments w i t h t h e e f f e c t s o f

a

continuous

springtime

fumigation

SO on CO u p t a k e and s t r u c t u r e o f t h e annual r i n g i n spruce done by 2 2 K e l l e r ( r e f . 20) p r o v e d t h a t SO c o n c e n t r a t i o n s , w h i c h do n o t cause t h e 2 development of v i s i b l e symptoms o f i n j u r y i n spruce, reduced t h e

with

p h o t o s y n t h e t i c a c t i v i t y and cambium growth. ring

decreased

and

the

The p r o d u c t i o n o f

the

reduction o f t h e growth o f several f o r e s t t r e e s i n experimental conditions

without

annual

amount and d e n s i t y o f l a t e wood was reduced. The and

field

v i s i b l e f o l i a r has been documented many t i m e s ( r e f . 19

and 21). Besides t h e f o l i a r a n a l y s i s o f n u t r i e n t s and tree the

pollutants

content

and

r i n g analyses, t h e n e x t v e r y i m p o r t a n t i n d i c a t o r o f f o r e s t d e c l i n e i s decomposition

rate

of

the

litter

cover,

which

in

the

high

i n c r e a s e s because o f an i n h i b i t i o n o f p i n e l i t t e r c o n c e n t r a t i o n s o f SO 2 which may be t h e r e s u l t o f d e c l i n e s i n t h e m i c r o b i a l a c t i v i t y , d e f i c i e n c y in

critical

system

nutrients,

together

m a t e r i a l s , and may be c l a s s i f i e d as forest.

The

litter

bags

a

with

"carpet

method may

be

an

accumulation o f t o x i c

effect"

used

for

in the

the

polluted

study o f f i e l d

d e c o m p o s i t i o n r a t e s ( r e f . 21). High and permanent a i r p o l l u t i o n i n a f o r e s t e d a r e a l e a d s

to

serious

damages f i n a l l y k i l l i n g almost a l l o f t h e p l a n t s and c r e a t i n g a d e s e r t . Poland

around

some

big

old

factories

with

heavy

d i s t i n g u i s h t h e f o l l o w i n g t h r e e d i s t i n c t zones ( r e f .

-

one

Where a i r p o l l u t i o n i s damaging t r e e s , t h e f o r e s t changes t o a p o o r - q u a l i t y woodland zone ( m o s t l y b r i c h

-

pollution

22):

-

B e t u l a v e r r u c o s a ) and

o c c a s i o n a l l y oak, p o p l a r , hagberry. Where a i r p o l l u t i o n i s l e t h a l (about 2 m e t r e s above t h e ground) p o o r - q u a l i t y woodland changes t o i n d u s t r i o g e n i c shrub communities (ref.

23) o f Pinus s i l v e s t r i s g r o w i n g as shrubs about 1

h i g h w i t h some J u n i p e r u s communis, S a l i x y o s m a r i n i f o l i a .

-

1.5 m e t r e s Quercus

r o b u r and Q. r u b r a , C a l l u n a v u l g a r i s , A r a b i s arenosa, Rumex acetosa. R. a c e t o s e l l a , Festuca o v i n a , M o l i n i a c o e r u l e a , Deschampsia f l e x u o s a , Ceratodan purpureus, Bryum c a e s p i t i c i u m and a few more species.

In can

36

The biomass p r o d u c t i o n of t h i s t y p e o f v e g e t a t i o n i s about 3000 t o 5000 kg o f d r y m a t t e r o f woody p l a n t s p e r h e c t a r e and t h a t i s about 1 t o 4% o f what can be produced i n such an area by normal v e g e t a t i o n undamaged by p o l l u t i o n . With s t i l l h i g h e r p o l l u t i o n near change

to

an

industriogenic

the

grassland

factories, with

Calamagrostic e p i g e i o s , C. v i l o s a and s i m i l a r grasses with

Arabis

arenosa communities.

shrubs

Deschampsia or

communities flexuosa

Silene

and

inflanta

If t h e contamination i s s t i l l higher i n

areas a d j o i n i n g f a c t o r i e s , t h e g r a s s l a n d changes t o naked m i n e r a l s o i l w i t h scattered

small

groups

v u l g a r i s i n some places.

of In

silene other

inflata, places

A r a b i s arenosa and A g r o s t i s

Festuca

ovina

or

Oeschampsia

f l e x u o s a grow. I n d u s t r i a l p o l l u t i o n a c t s as an agent o f changes

in

the

composition

selection

causing

t h a t a r e more s u s c e p t i b l e t o p o l l u t a n t s . F i n a l l y o n l y p a r t o f population

is

maintained

drastic

o f a forest, eliminating f i r s t a l l the trees which

was

able

to

withstand

the the

orginal polluted

environment. The development o f e l e c t r o p h o r e t i c t e c h n i q u e s f o r t h e a n a l y s i s o f isoenzymes and s t u d i e s o f provenances and c l o n e s o f d i f f e r e n t s p e c i e s o f t r e e s r e v e a l s t h a t an i n c r e a s e d t o l e r a n c e t o p o l l u t a n t s may have a basis

g r e a t t h a t t h e y may be comparable w i t h most SO

-

differences

between

species.

The

t o l e r a n t provenances o f Picea a b i e s a r e comparable i n r e s i s t a n c e

2 t o Picea pungens. Provenances o f Picea a b i e s f r o m mountains and are

genetic

242) D i f f e r e n c e s between provenances i n Picea a b i e s can be so

(ref.

the

north

more r e s i s t a n t t h a n l o w l a n d and Southern provenances ( r e f . 25

usually

and 2 6 ) . S t u d i e s of p o l l u t i o n r e s i s t a n c e i n some F i n n i s h s c o t s p i n e provenances showed t h a t t h e more r e s i s t a n t n o r t h e r n p i n e xeromorphism ( r e f .

27).

has a g r e a t e r

Significant difference i n the s e n s i t i v i t y

to

SO

2 i n l a r i x d e c i d u a and t h e h y b r i d p r o g e n i s o f l a r i x decidua x l e p t o l e p i s were

several times i n d i c a t e d ( r e f .

28,

differences i n the resistance t o 0

29,

3

30).

Kornosky

(ref.

31)

showed

i n F r a x i n u s pennsylvanica.

I n s p i t e o f a v e r y s h o r t p e r i o d o f p o l l u t i o n a c t i o n on p l a n t s t h e r e i s a l r e a d y e v i d e n c e o f some p l a n t p o p u l a t i o n s ' h a v i n g adapted t o a i r p o l l u t i o n ( r e f . 32). P o p u l a t i o n s o f herbaceus species growing under heavy s o i l o r a i r pollution such

for

many

conditions.

pollutants

were

generations

Adaptation described

have formed r a c e s g e n e t i c a l l y adapted t o

examples

or

variability

in

response

to

s e v e r a l t i m e s f o r d i f f e r e n t species, as S i l e n e

37

33.).

d i o i c a adapted f o r a h i g h c o n t e n t of copper carbonate ( r e f . carolinianum

to

Geranium

3 4 ) , A g r o s t i c s t e n i u s t o copper and

sulphur d i o x i d e (ref.

z i n c i n t h e s o i l ( r e f . 3 5 ) , L o l i u m perenne t o SO

( r e f . 36) e t c . 2 I t t a k e s many g e n e r a t i o n s t o produce a new r e s i s t a n t l i n e . I n t r e e s i t

is

a

very

difficult

Pinus

silvestris

L.,

Pinus c o n t a r t a Daugl., represent

task

due t o a l o n g p e r i o d f r o m g e r m i n a t i o n t o seed

However, i t i s known a l r e a d y t h a t many

production.

Picea

abies

L.,

tree

L a r i x spp.,

Pinus s t r o b u s L.

and

species

of

Brit.

taxifolia

o x i d a n t s ( r e f . 37). V a r i a b i l i t y i n t r e e species, a g r e a t area

as

Pinus ponderosa laws,

Pseudotsuga

g r e a t v a r i a b i l i t y a l s o i n t h e i r s e n s i t i v i t y t o SO

a

such

2’

fluoride,

distribution,

and

old

v e g e t a t i v e r e p r o d u c t i o n as w e l l as new b i o t e c h n o l o g i c a l methods o f b r e e d i n g may b r i n g r e s u l t s much f a s t e r t h a n i t m i g h t wide

international

be

anticipated.

However,

a

c o o p e r a t i o n i s needed i n t h e s e l e c t i o n o f r e s i s t a n t o r

l e s s s u s c e p t a b l e i n d i v i d u a l t r e e s i n areas o f permanent p o l l u t i o n

as

well

as i n t h e development o f new methods o f p r o p a g a t i o n and b r e e d i n g . Research on t h e h e r i t a b i l i t y o f t o l e r a n c e t o a i r and s o i l p o l l u t i o n i n Deschampsia c a e s p i t o s a showed t h a t i t i s due t o a d d i t i v e gene e f f e c t s ( r e f .

32), so i t s h o u l d show a r a p i d response t o s e l e c t i o n . segregation

pattern

of

progenis

of

controlled

Examination

crosses,

Anthoxanthum odoratum, and o t h e r species, i n d i c a t e s t h a t t h e pollution

as

of

shown f o r

tolerance

v e g e t a t i o n and f o r e s t s ,

way

to

f i r s t o f a l l i n an immediate emergency a c t i o n

i n Europe b u t a l s o i n l o n g t e r m a c t i v i t y . resistance

to

be determined by polygenes and w i t h some dominance t o t h e

might

t o l e r a n t p a r e n t s ( r e f . 38). The r e d u c t i o n o f p o l l u t i o n i s t h e o n l y save

the

But s e l e c t i o n

and

breeding

for

t o a i r and s o i l p o l l u t i o n o f t r e e s , shrubs and herbaceus p l a n t s

s h o u l d a l s o one o f t h e m a j o r a c t i v i t i e s o f b i o l o g i s t s s i n c e i t i s

doubtful

t h a t we s h a l l r e a c h a b s o l u t y c l e a n a i r and s o i l i n o u r p r e s e n t w o r l d , which i s overcrowded, over-armed and produces t o o many unnecessary p r o d u c t s . The b r e e d i n g o f t r e e s and shurbs r e s i s t a n t t o p o l l u t i o n s h o u l d the

direction

interna In

forest

true

accumulators

of

toxic

go

in

m a t e r i a l s w i t h as l i t t l e

damage as p o s s i b l e . many

Czechos o v a k i a , greatly

of

countries

of

Central

Europe

especially

Hoofed game a r e now a v e r y i m p o r t a n t cause stands

in

Poland,

t h e Federal R e p u b l i c o f Germany, game p o p u l a t i o n i n c r e a s e d of

damage

to

young

by browsing and f r a y i n g and even t o o l d e r stands by p e e l i n g

38

bark. I n Poland 250.000 Exceedingly

large

ha

of

forest

are

seriously

damaged

by

game.

game p o p u l a t i o n s endanger t h e r e s u l t s o f g e n e r a t i o n s i n Fed.

p a r t i c u l a r w i t h r e g a r d t o deciduous t r e e s p e c i e s and spruces i n o f Germany, and p i n e , f i r and s p r u c e i n

Rep.

Poland.

I n one o f t h e most p o l l u t e d f o r e s t s , Niepolomice, t h e r e a r e : r e d deer, 0.02

p e r ha i n deciduous f o r e s t s and almost 3 t i m e s as many i n

individual

t h e c o n i f e r o u s f o r e s t s . The roe-deer p o p u l a t i o n i s t w i c e as deciduous

forests

-

0.29

in

ha

average)

(0.014

39). I n Poland t h e r e a r e more t h a n 250 european b i s o n s , about 6 000

80

the

0.33 i n d i v i d u a l p e r ha, t h a n i n c o n i f e r o u s ones.

The w i l d boar range f r o m 0.009 t o 0.02 i n d i v i d u a l p e r (ref.

dense

red

000

80

deer,

wild

000

boars

and

nore

moose,

t h a n 400 000 roe-deer

a1 t o g e t h e r . The browse o f w i l d a n i m a l s i n sulphur

and

polluted

metals,

which

c o n c e n t r a t i o n i n deer a n t l e r s .

In the

pollution

heavy

deer

areas

results

in

is an

Niepolomice

contaminated increase

Forests

a

heavy

with

the q u a l i t y o f antlers i n t h i s Forest

-

25-30s

a

decrease

in

a

drop

in

i n t h e l a s t 20 y e a r s t h e r e has been

a 32% decrease i n t h e average w e i g h t o f a n t l e r s , a 29% decrease and

their

a n t l e r s show a 30% i n c r e a s e i n s u l p h u r , and a 10% i n c r e a s e

i n heavy m e t a l s ( r e f . 3 9 ) . The p o l l u t i o n o f f o o d i s blamed f o r

lenght,

with

in

trophy

quality

as

in

antler

estimated

from

i n t e r n a t i o n a l CJC t a b l e s . W i l d l i f e and e s p e c i a l l y b i g game, do n o t decrease t h e i r p o p u l a t i o n due to

a i r p o l l u t i o n , however t h e y do s u f f e r from t h e p o l l u t i o n o f food, which

should have i t s i n f l u e n c e i n f u t u r e . The development o f i n s e c t s i s i n some groups c l o s e l y pollution,

in

others

not.Leaf-eating

increased a i r p o l l u t i o n , but n o t i n a l l

related

to

air

i n s e c t s a r e u s u a l l y reduced by an genera,

secondary

pests

usually

increase t h e i r populations. In

polluted

especially

as

to

forests

the

number

cambiophagous

of

insects.

secondary The

Blastophagus p i n i p e r d a L. and Pissodes p i n i p h i l u s trees

attract

cambiophagous

water c o n t e n t i n t h e t r e e and increased

content

assemblage o f

or

insects, a

modified

cambiophagous

increases,

Host.

The

less

viable

p r o b a b l y due t o e i t h e r a decreased

decreasedosmotic composition

species

pests

most abundant s p e c i e s a r e

includes

of

pressure, etheric

or

oils.

Blastophagus

minor

to

an

Another Htg.,

39

Pityogenes

L.,

pini

Bidentatus Monochamus

Crioephalus

Hbst.,

P i t y o p h t h o r u s p i t y y o g r a p h u s Rotz.,

Ol.,

galloprovinccalis

L.,

rusticus

Acanthocinus

L.,

Rhagium i n q u i s i t o r

The occurance o f such a d i v e r s i t y and

Pissodes

L.,

aedilid

and C a l l i d i u m aenum Deg.

abundance

of

pests

results

in

a

considerable i n j u r y t o t h e t r e e s ( r e f . 39). A d e c l i n e i n grasshopper p o p u l a t i o n s experimental indicated.

sites

of

the

polluted

(Melanoplus

aera

of

S i m i l a r l y , a d e c l i n e i n saprophagous

and

Colstrip and

Eritettix) (USA)

in

has been

necrophagous

beetles

has been d e s c r i b e d , which l e a d s t o an a l t e r a t i o n of t h e decomposition r a t e s

.

o f l i t t e r ( r e f . 21). Industrial pollution insects

on

forests.

intensifies

the

action

of

some

E x o t e l e i a d o d e c e l l a and R h y a c i o n i a b o u l i a n a i n young

p i n e p l a n t a t i o n s i n t e n s i f y t h e i r i n j u r i o u s e f f e c t s . Others, lignicola

Htg.,

phytophagous

mostly

Cynips

i n c r e a s e t h e i r abundance i n young oak p l a n t a t i o n s .

These

i n s e c t s cause damage t o buds, and due t o t h e i r mass o c c u r r e n c e t h e y i n h i b i t t h e h e i g h t g r o w t h o f t r e e s , r e d u c i n g t h e growth of shrubs ( r e f . 3 9 ) . The f o r e s t i n v e n t o r y o f t h e i n f e s t a t i o n trees

in

the

Federal

Republic

of

with

Germany

insects

and

fungi

reveals t h a t i n contrast t o

b i o l o g i c a l r e s e a r c h r e s u l t s , t r e e s w i t h f o l i a g e damage symptoms trees

of

i n f e s t e d w i t h f u n g i and i n s e c t s ( s e v e r e l y damaged

w i t h o u t symptoms o f damage (13.8%), b u t t h e b a r k b e e t l e s

-

have

less

9.9%) t h a n t r e e s 3

develop

times

b e t t e r on damaged t r e e s t h a n on h e a l t h y ones ( r e f . 7 ) . The P o l i s h f o r e s t i n v e n t o r y ( r e f . 40) eating

insects

develop

with

shows

p o p u l a t i o n s o f secondary p e s t s develop much f a s t e r forests.

that

fungi

and

leave-

no c o n n e c t i o n t o a i r p o l l u t i o n damages, b u t in

polluted

areas

of

40 CONCLUSIONS

1. The massive f o r e s t damage i n Europe and N o r t h America, i n s p i t e o f o t h e r causes as d r o u g h t s , f u n g a l d i s e a s e s , i n s e c t s and windbreaks a r e t r i g g e r e d o f f by a i r p o l l u t i o n as t h e p r i m a r y cause and o n l y a decrease o f a i r p o l l u t i o n may save t h e f o r e s t from a f i n a l d e s t r u c t i o n . 2. The l o n g - r a n g e t r a n s b o u n d a r y t r a n s p o r t o f a i r p o l l u t a n t s m i g h t have a d e f i n i t e d i r e c t i n f l u e n c e on t h e v e g e t a t i o n i n n e i g h b o u r i n g c o u n t r i e s , where f o r e i g n i m p o r t e d a i r p o l l u t a n t s o v e r l a p w i t h l o c a l pollution.

It i s d i f f i c u l t t o prove t h e s t r o n g l y negative d i r e c t e f f e c t s

o f these p o l l u t a n t s throughout t h e countries t o t h i r d c o u n t r i e s over more t h a n 1 000

-

1 500 km, b u t t h e i n d i r e c t e f f e c t s o f a c i d r a i n s ,

m o s t l y t h r o u g h t h e s o i l , a r e obvious, e s p e c i a l l y i n a r e a s prone t o acidification.

3. Adequate methods o f e v a l u a t i o n and a l a r g e - s c a l e mapping o f f o r e s t areas, based on p o l l u t a n t s a c c u m u l a t i o n i n f o r e s t t r e e s , may b r i n g a f u l l p i c t u r e o f t h e r e a l t h r e a t and t h e sources o f damage. The r e s e a r c h and e v o l u t i o n o f f o r e s t damages s h o u l d be c a r r i e d o u t under t h e s u p e r v i s i o n o f t h e UNEP. 4. A wide i n t e r n a t i o n a l c o o p e r a t i o n i s needed i n t h e s e l e c t i o n o f r e s i s t a n t o r a t l e a s t l e s s s u s c e p t i b l e i n d i v i d u a l t r e e s i n areas o f permanent p o l l u t i o n , as w e l l as i n t h e development o f new methods o f p r o p a g a t i o n and b r e e d i n g . A v a r i a b i l i t y i n t r e e species, a g r e a t area o f d i s t r i b u t i o n ,

and o l d - f a s h i o n e d v e g e t a t i v e r e p r o d u c t i o n as

w e l l as new b i o t e c h n o l o g i c a l methods o f b r e e d i n g may b r i n g r e s u l t s much f a s t e r t h a n i t m i g h t be a n t i c i p a t e d .

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1979.

Bradshaw and T. M c N e i l l y , E v o l u t i o n and P o l l u t i o n ,

S t u d i e s i n B i o l o g y , no. 130. Edward Arnold, P r a t , Ber. D t . Bot. Ges.,

33.

S.

34.

G.E.

T a y l o r and W.H.

35.

K.A.

Walley, M.S.J.

1981, 76 pp.

102 (1934) 65-67.

Hurdy, Bot. gaz., Khan and A.D.

136 (1975) 312-315.

Bradshaw, H e r e d i t y , 32

(1974) 309-319. 36.

D.A.

37.

E.J.

Horsman, T.M.

Roberts and A.D.

Bradshaw, Nature, 276

(1978) 493-494. Ryder, i n J.A.

Advences, 38.

A i r P o l l u t i o n Damage t o V e g e t a t i o n

i n Chemistry S e r i e s 122, American Chemical S o c i e t y ,

Washington D.C., D.W.

Naegele (Ed.), 1973, pp. 75-84.

G a r t s i d e and T. M c N e i l l y , H e r e d i t y , 32 (1974) 287-297.

43

39.

W.

G r o d z i n s k i , J. Weiner and P.F.

Maycock (Ed.),

Forest

Ecosystems i n I n d u s t r i a l Regions, S p r i n g e r - V e r l a g ,

Berlin

e c t . 1984, 277 pp.

40.

Raport o s t a n i e zagrozenia srodowiska lesnego w p o l s c e , F o r e s t Res. Inst.,

Warszawa, 1984.

44 Table 1 F o r e s t damages i n s e l e c t e d c o u n t r i e s based on ECE d a t a ( r e f . 5, 6 ) f o r F.R.G.

7 ) f o r Poland on t h e Main

on Federal Government d a t a ( r e f .

S t a t i s t i c a l O f f i c e d a t a ( r e f . 8).

~

~~~~

~~

Country and Year o f date

~~

T o t a l f o r e s t Area o f f o r e s t area

c o l 1e c t ion

Region

damages

1000

% of

1000

ha

1and

ha

% of forest area

30.5

3

Local sources

5.2

Local sources

3

Rhone and Sein

Spain

1979

15 260

Italy

1983

5 341

France

1979

14 543

Alsace +

1984

428

40.6

1984

258

35.4

Nether1 ands 1984

281

Luxemburg

1984

87

I r l and

1979

317

4.6

3

Local sources

Great-

1979

2018

8.8

3

Local sources

1984

465

11.6

3

N o r t h -west e r n

3

3

J u t 1 and

Finland

1979

23 321

76.3

120

3

Local sources

Norway

1979

8 330

27.1

3

South - e a s t e r n

Sweden

1983

26 424

64.2

3

South Sweden

S w i t z e r l a n d 1983

1 052

26.5

278 26.7

Val 1ey

Lorraine Franche Comte

49

8.6

Scattered

18.5

Britain Denmark

105

S t a t e owned

Norway 200

34

Northern centers, Val a r i s

Austria

1979

3 754

44.8

330

Hungary

1985

1 594

17.3

170

9

Upper A u s t r i a

10

Local sources

Stryria, Tirol

45

Czechoslo-

1979

4 535

36.1

450

10

vakia

F.R.G.

1982 1983

7 318

35

1984 1985 Pol and

Canada

Ore Mnt.,

Iser

Mnt.

560

8

Ag 1ome r at ion

2 545

34

areas, r i d g e s

3 698

50

of central

3 824

52

highlands

1971

8 432

27

239

2.8

Sudety Mnt.,

1980

8 622

27.6

383

4.4

Upper S i 1e s i a

1983

8 639

27.6

465

5.4

Krakow, Torun,

1984

8 645

27.6

571

6.6

W1 o c l awek Reg.

1985

326 000

1100

1

Local sources

36

46

Selected information of forest damages broken down by t r e e species based on data for F.R.G. (ref. 7 ) . for Poland (ref. 1 7 ) and other countries ( r e f . 6 ) . __-I___

Country species

F.R.G. Yicea abies Pinus silv.

Abies alha Fagus Sil".

qurrcus spp.

Others Total Poland Picea abies

Italy Picea abies Abies Alha Pinus spp. Fagus silvarica Castanea sativa Oaksldecidousl Oakslevergreensl

Year of -_ survey

Uamage sta&e % 0 wichout I slighfly

damage

damagep___

___ 2 moderately damaged

I983 1'185 1983 1985 1983 1985 1983 1985 1983 198s 1983 1985 1983 1985

59.1 47.8 57 .o 42.5 24.0 12.8 73.7 45.5 84.8 44.7 83.6 69.5 65.6 49.1

30 .0 28.2 32 40.5 27 20.5 22 40.1 13 38.9 9 22.7 24.7 32.7

10 .o 21.4 10 15.3 42 50.3 4 13.1 2 15.7 7 6.7 8.7 17

1983 1983

66 73

23 25

10

91 92 95 93 9J 95

7 4 4 5

1983

98

iktherlands 1984 Total Coniferous Hoardleaved Pinus silvestris Pinus spp. Picea abies Pseudotsuga men. quercus s p p . Fagus silvatica Broadleaved others Luxemburg Conifers 60 Y.O. 6 0 years old Broadleaved Total f o r e s t s

1985

Switzerland Coniferuus Broadleavrd

1984

2

5

4

1

3

+

2.951

40

I .464

20

7.0 16.4 0.3 1.3 0.2 0.7 0.4

176

I.o I .7

1.250

2 17

615

8

950

13

I .0 2.1

7.371

I00

I

631 6.267

7 72

I 2 I I 1 I 1

449 117 478 761 760 1.137 188

1.1

40 .0 44.0 28.3 51 34 28 39 38 24 23

8.0 11 .o 3.7 12 8 7 9 4

1.5 I.5 I .o 3 1 3 2 1

2

I I

59.0 90.5 71.6 79.1

34.7 6.4 23.7 16.9

5.8 1.7 4.0 3 .0

h2.4 75.1

2 8 .n

21.7

8.2 3.0

-

Area of tree specie? 1000 % of total ha forested area

0.9 2.6

50.5 43.5 67.0 34 57 62 50 57 71 74

1

4 severely

damaged aid-dead __

0.5 I .4 0.7 1.o

1.4 0.2 _.

113 16 13 16 44 9 47

47

Fig. 1

Massive domoges

Local domages

These figures represent the percentage of sulphur in Scot Pine needles

D i s t r i b u t i o n o f f o r e s t damages i n Europe due t o a i r p o l l u t i o n as a primary source

-

compare Tabel 1.

Area w i t h t h e massive damages has as a r u l e , a h i g h c o n t e n t o f sulphur i n p i n e needles (above 0.15%) areas w i t h l o c a l damages about 0.10 t o 0.15%, and f a i r l y clean below 0.10.

48

Fig. 2

A map o f t h e w o r l d showing s u l p h a t e - s u l p h u r c o n c e n t r a t i o n s , e x c l u d i n g 3 sea s p r a y s u l p h a t e , i n w i n t e r i n SC),-S yg/m ( d a t a from EMEP), and c o n c e n t r a t i o n s o f SO and f l u o r i n e compounds i n t h e 2 a i r o f t h e d i f f e r e n t w o r l d l o c a l i t i e s ( r e f . 9 and 10). The i m p o r t a n c e o f t h e North-East o f t h e USA and C e n t r a l Europe i s obvious, b u t w i t h i n t h e c e n t r e s of g l o b a l e m i s s i o n s a b i g v a r i a t i o n o f a i r p o l l u t i o n always o c c u r s (see f i g u r e s f o r d i f f e r e n t p l a c e s ) .

49

Fig. 3

Sulphur accumulation i n p i n e needles i n Poland as a b i o i n d i c a t o r o f a i r pollution.

Zone I represents t h e l e v e l o f sulphur i n needles as

found i n clean areas, zone I V represents a t l e a s t t h e double c o n t e n t s u l p h u r and i s considered as t o x i c f o r pine, spruce and fir. In t h e two i n t e r m e d i a t e zones t h e r e a r e commonly l e s s contaminated small l o c a l areas.

50

Fig. 4

BIALOWIEZA PFUMEVAL FOREST fairly clean area

UPPER SlLESlAN INDUSTRiAL DISTRICT heavily polluted area

---

r///A

1976-1977 sulphur content in needles in their second year growth

SO2 contents in the air [month mean v a l u e ] the samples colection period

Accumulation o f sulphur i n p i n e needles i n r e l a t i o n t o t h e sulphur content i n t h e a i r . The content of sulphur f l u c t u a t e s through t h e year, e s p e c i a l l y i n h e a v i l y p o l l u t e d areas, depending on t h e sulphur content i n t h e a i r , and t h e p h y s i o l o g i c a l t r a n s f o r m a t i o n w i t h i n t h e p l a n t s throughout t h e growing season. These data served t o c o n s t r u c t t h e map presented i n F i g . 3.

51

Fig. 5

_I

400

300 200

--....=...... .... .... .. N

P

K

S

Ca

Mg

Fe

Cu

Zn

Mn

No

CI

asch

The chemical composition of p i n e i n f a i r l y clean areas shown as a 100% l i n e and i n h e a v i l y p o l l u t e d areas as a per cent o f t h e content

of t h e clean area. The content o f each element i s shown i n t h r e e columns t h e f i r s t represent t h e c u r r e n t growth, t h e second - p r e v i o u s y e a r ' s

-

growth, and t h e t h i r d column t h e t h i r d y e a r ' s growth of needles. The b i g g e s t changes a r e i n t h e contents of Zn, F and S by

- an

increase o f 300%

-

p o l l u t i n g elements as Pb,

600%, and o n l y Mn c o n c e n t r a t i o n deCreaSeS

50% i n comparison t o the c o n t r o l area.

53 T. Schneider (Editor)/Acidificathonand its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

THE IMPACT OF OZONE ON AGRICULTURE AND ITS CONSEQUENCES DAVID T. TINGEY U.S.

E n v i r o n m e n t a l P r o t e c t i o n Agency, Environmental Research L a b o r a t o r y ,

C o r v a l l i s , OR

97333 (USA)

ABSTRACT Given i t s h i g h l e v e l o f p h y t o t o x i c i t y and d i s t r i b u t i o n o f e l e v a t e d concent r a t i o n s o v e r b r o a d g e o g r a p h i c areas, 03 i s c o n s i d e r e d t h e most c r i t i c a l a i r p o l l u t a n t a f f e c t i n g vegetation i n t h e United States, Diverse experimental methods have been used t o assess t h e impacts o f 03 on t h e c r o p y i e l d . Comparisons o f p l a n t g r o w t h and y i e l d i n c h a r c o a l - f i l t e r e d o r u n f i l t e r e d a i r and t h e use o f chemical p r o t e c t a n t s show t h a t ambient 03 l e v e l s w i l l reduce t h e growth and y i e l d o f numerous p l a n t species. Ozone s t u d i e s i n open-top f i e l d - e x p o s u r e chambers have p r o v i d e d exposure-response f u n c t i o n s needed t o e v a l u a t e t h e economic i m p a c t s o f 0 3 on a g r i c u l t u r e . Exposure-response f u n c t i o n s have been developed f o r a range of’legume, g r a i n , f i b e r and h o r t i c u l t u r a l c r o p s . Y i e l d r e d u c t i o n s (10%) were p r e d i c t e d f o r s e v e r a l c r o p s p e c i e s when t h e 7-hr seasonal mean c o n c e n t r a t i o n exceeded 0.04 t o 0.05 ppm. F o r some s e n s i t i v e c u l t i v a r s o f wheat, k i d n e y bean and soybean, 10% y i e l d r e d u c t i o n s o c c u r r e d a t 7 - h r mean c o n c e n t r a t i o n s o f 0.028 t o 0.033 ppm. Recent s t u d i e s , u s i n g exposure-response f u n c t i o n s developed i n open-top chambers, have a t t e m p t e d t o assess t h e n a t i o n a l economic consequences o f 03 e f f e c t s on a g r i c u l t u r e . These s t u d i e s i n d i c a t e t h a t e l e v a t e d 0 3 c o n c e n t r a t i o n s a r e c o s t i n g U.S. a g r i c u l t u r a l producers and consumers between 1.2 and 2.4 b i l l i o n d o l l a r s a n n u a l l y . INTRODUCTION Ozone e x e r t s a p h y t o t o x i c e f f e c t on v e g e t a t i o n o n l y i f enough d i f f u s e s f r o m t h e ambient a i r i n t o t h e l e a f ’ s s e n s i t i v e c e l l u l a r s i t e s t o cause an impact, F o l i a r i n j u r y i s one o f t h e e a r l i e s t and most o b v i o u s m a n i f e s t a t i o n s o f an 03 e f f e c t , b u t i m p a c t s can a l s o o c c u r on o t h e r p l a n t organs, c a u s i n g e f f e c t s r a n g i n g f r o m reduced p l a n t growth and decreased y i e l d t o changes i n c r o p q u a l i t y and a l t e r a t i o n s i n s u s c e p t i b i l i t y t o a b i o t i c and b i o t i c s t r e s s e s . Y i e l d Loss

--

Definition-

Y i e l d l o s s i s d e f i n e d as an impairment o r decrease i n t h e i n t e n d e d use o f t h e p l a n t o r i t s product.

T h i s concept o f y i e l d loss i n c l u d e s r e d u c t i o n s i n

a e s t h e t i c v a l u e s , t h e o c c u r r e n c e o f f o . l i a r i n j u r y (changes i n p l a n t appearance), and l o s s e s i n w e i g h t , number, o r s i z e o f t h e p l a n t organ t h a t i s normally harvested.

Y i e l d loss may a l s o i n c l u d e changes i n c r o p q u a l i t y .

54

--

Y i e l d Loss

Methods

To assess t h e impact o f 03 on p l a n t y i e l d , d i v e r s e e x p e r i m e n t a l methods have been used, r a n g i n g f r o m s t u d i e s under h i g h l y c o n t r o l l e d c o n d i t i o n s t o exposures u s i n g f i e l d - e x p o s u r e systems and chamberless systems, i n c l u d i n g chemical protectants.

To d e t e r m i n e t h e impact of 03 on p l a n t growth and y i e l d and t o

p r o v i d e d a t a f o r economic assessments, t h e e x p e r i m e n t a l c o n d i t i o n s must m i n i mize d e v i a t i o n s f r o m t h e t y p i c a l environment i n which t h e c r o p ( s ) i s grown.

It

i s a l s o i m p o r t a n t t o i n s u r e t h a t t h e e x p e r i m e n t exposure regimes a r e represent a t i v e o f t h e p o l l u t a n t c o n c e n t r a t i o n range and frequency f o r t h e area i n which t h e c r o p i s grown o r f o r which i n f e r e n c e s a r e t o be made. Open-top f i e l d exposure chambers ( r e f . 1, 2 ) a r e used most f r e q u e n t l y t o e s t i m a t e y i e l d l o s s e s because t h e y p e r m i t c r e a t i o n o f a range o f 03 exposures and can approximate t y p i c a l c u l t u r a l c o n d i t i o n s .

The open-top d e s i g n p e r m i t s

p l a n t s t o be grown i n s o i l under e n v i r o n m e n t a l c o n d i t i o n s comparable t o t h e ambient.

The d e s i g n p e r m i t s t h e d e t e r m i n a t i o n o f t h e e f f e c t s o f t h e ambient

p o l l u t a n t burden on p l a n t y i e l d by comparing t h e d i f f e r e n c e s i n p l a n t y i e l d between f i l t e r e d and u n f i l t e r e d chambers.

P l a n t s can be exposed t o c h a r c o a l -

f i l t e r e d a i r and a range o f 03 c o n c e n t r a t i o n s above and below t h e c u r r e n t ambient l e v e l so t h a t exposure-response

f u n c t i o n s can be developed ( r e f . 3 , 4).

Chemical p r o t e c t a n t s have been used t o a v o i d p o s s i b l e chamber i n f l u e n c e s on y i e l d loss e s t i m a t e s ( r e f . 5 ) .

The c r o p s a r e grown under t y p i c a l f i e l d c o n d i -

t i o n s , t r e a t e d w i t h p r o t e c t a n t and exposed t o ambient p o l l u t i o n .

Yield loss i s

o b t a i n e d b y comparing p l a n t y i e l d f r o m p l o t s t r e a t e d w i t h t h e 03 p r o t e c t a n t t o t h e y i e l d from untreated p l o t s .

However, u s i n g t h e p r o t e c t a n t , o n l y a s i n g l e

p o l l u t a n t t r e a t m e n t i s p o s s i b l e a t a g i v e n l o c a t i o n ; c o n s e q u e n t l y exposureresponse f u n c t i o n s cannot be developed.

A l s o , t h e d a t a must be i n t e r p r e t e d

c a r e f u l l y because t h e chemical p r o t e c t a n t may a l t e r p l a n t performance. ESTIMATES OF YIELD LOSS

Ambient A i r E a r l y r e s e a r c h comparing c r o p y i e l d s between c h a r c o a l - f i l t e r e d and u n f i l t e r e d a i r documented t h a t t h e ambient l e v e l o f photochemical o x i d a n t s reduced y i e l d o f c i t r u s , yrape, tobacco, c o t t o n , and p o t a t o ( r e f . 6 ) .

Subsequent

s t u d i e s c o n f i r m e d t h a t ambient l e v e l s o f 03 were h i g h enough t o i m p a i r p l a n t yield. bean

For example, ambient 03 reduced t h e y i e l d s o f tomato -- 33% ( r e f .

--

cultivars

+1 t o 26% ( r e f . 7 - 9 ) ,

--

9 and 28% ( r e f .

soybeans

--

7),

20% ( r e f . 10, 11) and t w o sweet c o r n

12).

Chemical P r o t e c t a n t s Chemical p r o t e c t a n t s have been used t o e s t i m a t e t h e impact o f ambient 03 on t h e y i e l d o f s e v e r a l c r o p s p e c i e s ( T a b l e 1).

Using t h i s approach, y i e l d s were

55 reduced 18 t o 41% when t h e ambient o x i d a n t c o n c e n t r a t i o n exceeded 0.08 ppm f o r

5 t o 18 days o v e r t h e c r o p ' s growing season.

These d a t a s u p p o r t t h e c o n c l u -

s i o n s f r o m s t u d i e s comparing y i e l d i n c h a r c o a l - f i l t e r e d and u n f i l t e r e d a i r , i.e.,

ambient l e v e l s o f 03 can be h i g h enough t o i m p a i r c r o p p r o d u c t i o n .

TABLE 1 The e f f e c t s of ambient 03 on c r o p y i e l d as determined by t h e use o f chemical p r o t e c t a n t s .a Species Beans (.q_r e e n )

Yield reduction % o f control 41

Onion

38

03 exposure

> 0.08 f o r t o t a l o f 27 h r o v e r 3.5 months

Reference 13

> 0.08 on 5 days o u t o f 48 > 0.08 on 15 days o v e r 3 months > 0.08 on 11 days ( t o t a l o f 34 h r )

14

15

Tomato

30

Bean ( d r y )

24

Tobacco

18

> 0.08 on 14 days d u r i n g t h e summer

17

Potato

36

> 0.08 ppm on 18 days ( t o t a l o f 68 h r ) o v e r 3 months

18

Potato

25

---b

19

o v e r 3 months

16

A l l t h e s p e c i e s were t r e a t e d w i t h t h e a n t i o x i d a n t EDU except t h e bean s t u d y ( r e f . 1 3 ) which used t h e s y s t e m i c f u n g i c i d e benomyl. Y i e l d r e d u c t i o n was determined by comparing t h e y i e l d s o f p l a n t s t r e a t e d w i t h chemical p r o t e c t a n t s ( c o n t r o l ) t o t h o s e t h a t were n o t t r e a t e d . T h i s s t u d y was r u n o v e r 2 y e a r s when t h e O3 doses were 65 and 110 ppm/hr. r e s p e c t i v e l y , b u t t h e y i e l d loss was s i m i l a r b o t h y e a r s . C o n t r o l l e d Exposures Most e x p e r i m e n t a l t e c h n i q u e s t h a t assess y i e l d l o s s f r o m c o n t r o l l e d exposures have used a range o f 03 c o n c e n t r a t i o n s and r e g r e s s i o n approaches t o develop exposure-response f u n c t i o n s which r e l a t e c r o p y i e l d loss t o 03 exposure. The r e g r e s s i o n approaches p e r m i t t h e e s t i m a t i o n o f t h e 03 impact on p l a n t y i e l d over t h e range o f c o n c e n t r a t i o n s and i t i s p o s s i b l e t o i n t e r p o l a t e between t r e a t m e n t means; t h i s i s n o t p o s s i b l e w i t h a n a l y s i s o f v a r i a n c e methods.

Most

o f t h e c u r r e n t l y a v a i l a b l e y i e l d loss f u n c t i o n s ( r e f . 3, 20) have expressed t h e

03 exposure as t h e 7-hr (9:UO AM u n t i l 3:59 PM) seasonal mean c o n c e n t r a t i o n . Examples o f exposure-response f u n c t i o n s a r e shown i n F i g u r e 1.

A Weibull

f u n c t i o n ( r e f . 21) was used t o model t h e change i n c r o p y i e l d i n r e l a t i o n t o t h e 03 c o n c e n t r a t i o n .

The d e r i v e d exposure-response f u n c t i o n s can be used t o

determine t h e c o n c e n t r a t i o n s p r e d i c t e d t o cause a s p e c i f i c y i e l d l o s s o r t o e s t i m a t e t h e p r e d i c t e d y i e l d loss t h a t would r e s u l t f r o m a s p e c i f i c 03 concentration.

B o t h approaches have been used t o summarize t h e d a t a on c r o p

responses t o 03 u s i n g a W e i b u l l f u n c t i o n .

As

an example, t h e 03 c o n c e n t r a t i o n s

56

6000

AISoybeon (Davis) Raleigh, 1981 and 1982

Argonne, 1982 and 1983

0

5000 0

r

..

.Q)

4000

)r

rn

Q1

$

3000

2000 I

I

I

I

I

I

,

0

0.04

0.08

0.10

0 6

0, concentration, ppm

0, concentration, ppm

F i g u r e 1. Examples o f t h e e f f e c t s o f 03 on t h e y i e l d o f soybean and wheat c u l t i v a r s o v e r t w o y e a r s . The 03 c o n c e n t r a t i o n s a r e expressed a s 7 - h r seasonal mean c o n c e n t r a t i o n s . The c u l t i v a r s were s e l e c t e d t o i l l u s t r a t e y e a r - t o - y e a r v a r i a t i o n i n p l a n t response t o 03. The soybean d a t a a r e f r o m Heck e t a l . ( r e f . 20) and t h e wheat d a t a a r e f r o m Kress e t a1 ( r e f . 22).

.

p r e d i c t e d t o cause a 10 o r 30% y i e l d loss have been e s t i m a t e d ( T a b l e 2).

For

a p p r o x i m a t e l y 56% o f t h e s p e c i e s / c u l t i v a r s l i s t e d , mean y i e l d r e d u c t i o n s were p r e d i c t e d t o exceed 10% when t h e 7-hr seasonal mean 03 c o n c e n t r a t i o n exceeded

0.05 ppm.

I n s e n s i t i v e c r o p s , 7 - h r seasonal mean c o n c e n t r a t i o n s o f 0.028 t o

0.033 ppm were p r e d i c t e d t o cause a 10% y i e l d loss i n Vona wheat, k i d n e y bean, and Hodgson soybean.

A t a 7 - h r seasonal mean 03 c o n c e n t r a t i o n o f 0.04 ppm,

mean y i e l d r e d u c t i o n s ranged f r o m 0 i n sorghum, b a r l e y , and a c o r n c u l t i v a r t o a h i g h o f 28.8% i n Vona wheat. The g r a i n c r o p s were g e n e r a l l y l e s s s e n s i t i v e t o 03 t h a n were t h e o t h e r s p e c i e s ( T a b l e 2).

F o r a l l g r a i n c r o p s , mean y i e l d r e d u c t i o n s a t 7-hr seasonal

mean c o n c e n t r a t i o n s o f 0.04 ppm were p r e d i c t e d t o be l e s s t h a n 5% except f o r t h e Roland and Vona wheat c u l t i v a r s .

The d a t a a l s o demonstrate t h a t s e n s i -

t i v i t y d i f f e r e n c e s w i t h i n a s p e c i e s may be as l a r g e as d i f f e r e n c e s between species.

F o r example, a t 0.04 ppm 03, e s t i m a t e d y i e l d l o s s e s ranged f r o m 2 t o

15% i n soybean and f r o m 0 t o 28% i n wheat.

57 TABLE 2 C o m p i l a t i o n o f 03 c o n c e n t r a t i o n s p r e d i c t e d t o cause 10% and 30% y i e l d l o s s e s as w e l l as y i e l d l o s s e s p r e d i c t e d t o o c c u r a t 7 - h r seasonal mean 03 c o n c e n t r a t i o n s

of 0.04 and 0.06 ppm.a 7-hr seasonal mean

03 c o n c e n t r a t i o n s , ppm

Species

p r e d i c t e d t o cause y i e l d losses o f : 10% 30%

Legume Crops Soybean, Corsoy 0.048 Soybean, D a v i s - (81) 0.038 Soybean, Davis (CA-82) 0.048 Soybean, Davis (PA-82) 0.059 Soybean, Essex 0.048 Soybean, F o r r e s t 0.076 Soybean, W i 11 iams 0.039 Soybean, Hodgson 0.032 Bean, Kidney 0.033 Peanut, NC-6 0.046 G r a i n Crops Wheat, Abe 0.059 Wheat. A r t h u r 71 0.056 Wheat, Roland 0.039 Wheat, Vona 0.028 Wheat, Blueboy I 1 0.088 Wheat, Coker 47-27 0.064 Wheat, Hol l y 0.099 Wheat, Oasis 0.093 Corn, PAG 397 0.095 Corn, P i o n e e r 3780 0.075 Corn, Coker 16 0.133 Sorghum, DeKal b-28 0.108 B a r l e y , Poco 0.121 F i b e r Crops C o t t o n , A c a l a SJ-2 ( 8 1 ) 0.044 Cotton: Acala SJ-2 (82j 0.032 C o t t o n , S t o n e v i 11 e 0.047 H o r t i c u l t u r a l Crops Tomato, M u r r i e t a (81) 0.079 Tomato, M u r r i e t a ( 8 2 ) 0.040 L e t t u c e , Empi r e 0.053 Spinach, America 0.046 Spinach, H y b r i d 0.043 S p in ach , V irof 1ay 0.048 Spinach, W h i t e r Bloom 0.049 Turnip, Just Right 0.043 T u r n i p , Pur Top W.G. 0.040 TurniD. 0.036 . _ Shocloin T u r n i p , Tokyo Cross 0.053 a The y i e l d l o s s e s a r e d e r i v e d f r o m W e i b u l l control yields i n charcoal-filtered air. response f u n c t i o n s ( r e f . 20). Ambient A i r Q u a l i t y

--

Percent y i e l d losses predicted t o occur a t 7-hr seasonal mean 03 c o n c e n t r a t i o n o f : 0.04 ppm 0.06 ppm

0.082 0.071 0.081 0.081 0.099 0.118 0.093 0.066 0.063 0.073

6.4 11.5 6.4 2.0 7.2 1.7 10.4 15.4 14.9 6.4

16.6 24.1 16.5 10.4 14.3 5.3 18.1 18.4 28.0 19.4

0.095 0.094 0.067 0.041 0.127 0.107 0.127 0.135 0.126 0.111 0.175 0.186 0.161

3.3 4.1 10.3 28.8 0.5 2.2 0.0 0.4 0.3 1.4 0.0 0.0 0.0

10.4 11.7 24.5 51.2 2.0 8.4 0.9 2.4 1.5 5.1 0.3 2.7 0.5

0.096 0.055 0.075

8.3 16.1 4.6

16.2 35.1 16.2

0.108 0.059 0.075 0.082 0.082 0.080 0 A80 0.064 0.064 0.060 0.072

0.8 10.3 0.0 6.8 2.6 6.0 5.8 7.7 10.1 13.0 3.3

3.7 31.2 16.8 17.2 9.2 16.7 16.5 24.9 26.5 29.7 15.6

e q u a t i o n s and a r e based on t h e Data a r e d e r i v e d from exposure-

R e l a t i o n s h i p t o Y i e l d Loss

An u n d e r s t a n d i n g o f ambient c o n c e n t r a t i o n s o f 03 i s needed t o p l a c e t h e c o n c e n t r a t i o n s p r e d i c t e d t o cause 10 and 30% y i e l d l o s s e s i n p e r s p e c t i v e .

For

58 example, a i r m o n i t o r i n g d a t a f o r a s i n g l e 03 season were o b t a i n e d from r u r a l o r remote m o n i t o r i n g s i t e s t h r o u g h o u t t h e U n i t e d S t a t e s ( T a b l e 3 ) .

For these

s i t e s , t h e 7 - h r seasonal mean 03 c o n c e n t r a t i o n averaged 0.044 ppm w i t h a range

o f 0.019 t o 0.057

ppm.

T h i s range encompasses t h e same c o n c e n t r a t i o n range

p r e d i c t e d t o cause a 10% y i e l d loss i n numerous c r o p s p e c i e s / c u l t i v a r s ( T a b l e 2).

The 12-hr seasonal mean a t most s i t e s i s a p p r o x i m a t e l y equal t o t h e 7 - h r

A t most m o n i t o r i n g s i t e s , t h e number o f h o u r s g r e a t e r t h a n 0.08

seasonal mean.

ppm was s i m i l a r t o o r g r e a t e r t h a n t h e exceedances a s s o c i a t e d w i t h c r o p y i e l d l o s s (Table 1). TABLE 3 Examples o f ambient ozone c o n c e n t r a t i o n s a t r u r a l and remote m o n i t o r i n g s i t e s . a

A i r Quality Statistic

Mean

St. Dev.

Max.

Min.

7-hr Seasonal Mean

0.043

0.007

0.057

0.019

12-hr Seasonal Mean

0.041

0.006

0.055

0.021

Hours Above 0.08 ppm

106

104

474

0

Hours Above 0.10 ppm

19

34

195

0

4

12

74

0

Hours Above 0.12

ppm

a Data c o u r t e s y of Ted Johnson, P E I A s s o c i a t e s , Durham, N o r t h C a r o l i n a .

Mean c o n c e n t r a t i o n s a r e expressed i n ppm. The d a t a a r e f r o m 82 r u r a l and remote m o n i t o r i n g s i t e s f r o m 32 s t a t e s a c r o s s t h e U.S. f o r a s i n g l e y e a r (ozone season) between 1982 and 1984.

Y i e l d Loss

--

Physiological Basis

S p e c i f i c s t u d i e s have n o t c l e a r l y e s t a b l i s h e d t h e c a u s e ( s ) o f t h e y i e l d losses b u t several f a c t o r s s i n g l y o r i n combination probably contribute.

Ozone

can reduce f l o w e r i n g , seed s e t , and f e r t i l i z a t i o n processes i n p l a n t s ( r e f . 23-27).

Experiments have suggested t h a t p a r t o f t h e 03 i m p a c t on y i e l d r e s u l t s

f r o m a s i m u l a t i o n of l e a f d r o p and senescence ( r e f . 28-31). measured by gas-exchange, 32-34).

i s i n h i b i t e d by 03 (0.05

P h o t o s y n t h e s i s , as

ppm and h i g h e r ) ( r e f . 6,

Biochemical s t u d i e s have a l s o shown t h a t 03 (0.12

ppm f o r 2 h r )

i n h i b i t s an enzyme which c a t a l y z e s t h e a s s i m i l a t i o n o f C02 ( r e f . 35).

Ozone

a l s o a l t e r s t h e p a t t e r n by which p h o t o a s s i m i l a t e i s p a r t i t i o n e d t h r o u g h t h e p l a n t w i t h l e s s o f i t b e i n g t r a n s l o c a t e d t o t h e r o o t s and r e p r o d u c t ve organs ( r e f . 36-40). Y i e l d Loss

--

Factors A f f e c t i n g

Numerous f a c t o r s , r a n g i n g f r o m a b i o t i c and b i o t i c f a c t o r s t o t h e presence o f o t h e r p o l l u t a n t s and t h e temporal dynamics o f t h e exposure, can mod f y p l a n t

59 response t o 03.

However, f a c t o r s i n f l u e n c i n g p l a n t water r e l a t i o n s ( r e l a t i v e

h u m i d i t y and s o i l m o i s t u r e s t r e s s ) and t h e presence o f o t h e r p o l l u t a n t s a r e t h o u g h t t o be t h e most i m p o r t a n t . P l a n t response t o 03 tends t o i n c r e a s e w i t h i n c r e a s i n g r e l a t i v e h u m i d i t y ( r e f . 6).

The r e l a t i v e h u m i d i t y e f f e c t appears t o be r e l a t e d t o stomatal

aperture, which tends t o increase w i t h increasing r e l a t i v e humidity. McLaughlin and T a y l o r ( r e f . 41) demonstrated t h a t p l a n t s absorb s i g n i f i c a n t l y more 03 a t h i g h h u m i d i t y t h a n a t l o w h u m i d i t y .

As s o i l m o i s t u r e decreases, p l a n t w a t e r s t r e s s i n c r e a s e s and t h e r e i s a r e d u c t i o n i n p l a n t s e n s i t i v i t y t o 03 (e.g.,

r e f . 6, 42).

The reduced 03

s e n s i t i v i t y i s a p p a r e n t l y r e l a t e d t o s t o m a t a l c l o s u r e , which reduces 03 uptake ( r e f . 6, 43, 4 4 ) .

Water s t r e s s does n o t c o n f e r a permanent t o l e r a n c e t o 03;

once t h e w a t e r s t r e s s has been a l l e v i a t e d , t h e p l a n t s r e g a i n t h e i r s e n s i t i v i t y t o 03 ( r e f . 44). Menser and Heggestad ( r e f . 45) p r o v i d e d t h e i n i t i a l impetus t o s t u d y t h e i n t e r a c t i o n o f 03 w i t h S02.

They showed t h a t Be1 W-3 tobacco p l a n t s exposed t o

03 (0.03 ppm) o r SO2 (0.24 t o 0.28 ppm) were u n i n j u r e d b u t t h a t s u b s t a n t i a l f o l i a r i n j u r y r e s u l t e d when t h e p l a n t s were exposed t o b o t h gases s i m u l t a n e ously.

Subsequent s t u d i e s have c o n f i r m e d and extended t h e o b s e r v a t i o n t h a t

c o m b i n a t i o n s o f 03 and SO2 may cause more v i s i b l e i n j u r y on many s p e c i e s t h a n expected, based on t h e i n j u r y caused by t h e i n d i v i d u a l gases (e.g., 46, 47).

r e f . 43,

T h i s i n j u r y enhancement i s most common a t l o w c o n c e n t r a t i o n s o f each

gas and a l s o when t h e amount o f f o l i a r i n j u r y induced by each gas, i n d i v i d u a l l y , i s small.

A t h i g h e r c o n c e n t r a t i o n s o r when e x t e n s i v e i n j u r y occurs,

t h e e f f e c t s o f t h e i n d i v i d u a l gases t e n d t o be l e s s t h a n a d d i t i v e . F i e l d s t u d i e s have been conducted t o d e t e r m i n e t h e i n f l u e n c e of SO2 on p l a n t response t o 03 on s e v e r a l p l a n t s p e c i e s :

50), and p o t a t o e s ( r e f . 51).

soybean ( r e f . 48, 49), beans ( r e f . 9,

I n t h e s e s t u d i e s , 03 reduced p l a n t y i e l d b u t SO2

had no s i g n i f i c a n t e f f e c t and d i d n o t i n t e r a c t w i t h 03 t o reduce y i e l d u n l e s s t h e SO2 exposure c o n c e n t r a t i o n s and f r e q u e n c y o f occurrence were much g r e a t e r t h a n t h o s e t y p i c a l l y f o u n d i n t h e ambient a i r i n t h e U n i t e d S t a t e s . Many o f t h e s t u d i e s t o d e t e r m i n e t h e i n f l u e n c e o f p o l l u t a n t combinations on p l a n t growth and y i e l d have used e x p e r i m e n t a l exposures more i n t e n s e t h a n t h o s e found i n t h e ambient a i r ; c o n s e q u e n t l y t h e a p p l i c a b i l i t y o f t h e y i e l d r e s u l t s f r o m most p o l l u t a n t c o m b i n a t i o n s t u d i e s t o ambient c o n d i t i o n s i s n o t known.

An

a n a l y s i s o f ambient a i r m o n i t o r i n g d a t a i n d i c a t e d t h a t t h e j o i n t co-occurrence o f p o l l u t a n t s t e n d e d t o be i n f r e q u e n t ( r e f . 52).

ECONOMIC CONSEQUENCES OF OZONE EXPOSURE V a r i o u s methods have been used f o r e s t i m a t i n g economic losses, f r o m s i m p l e monetary c a l c u l a t i o n s t o more complex economic assessment methodologies.

The

60 s i m p l e procedures c a l c u l a t e d monetary e f f e c t s b y m u l t i p l y i n g p r e d i c t e d y i e l d o r p r o d u c t i o n changes r e s u l t i n g f r o m exposure t o 03 by an assumed c o n s t a n t c r o p price.

T h i s p r o c e d u r e f a i l s t o account f o r p o s s i b l e p r i c e changes r e s u l t i n g

f r o m y i e l d changes and does n o t account f o r t h e processes u n d e r l y i n g economic response. To conduct a r e l i a b l e economic assessment, s e v e r a l t y p e s o f i n f o r m a t i o n a r e needed

--

d a t a t o r e l a t e c r o p response t o 03 c o n c e n t r a t i o n s under a c t u a l f i e l d

c o n d i t i o n s and a i r q u a l i t y d a t a t o d e s c r i b e c u r r e n t o r h y p o t h e t i c a l 03 exposures t o c r o p s i n each p r o d u c t i o n area.

The assessment methodology s h o u l d

r e p r e s e n t t h e economic b e h a v i o r o f p r o d u c e r s and consumers as t h e y a d j u s t t o changes i n c r o p y i e l d s and p r i c e s t h a t may accompany changes i n 03 a i r q u a l i t y . N a t i o n a l - l e v e l e s t i m a t e s o f t h e economic i m p a c t o f 03 on a g r i c u l t u r e ( i n c l u d i n g b o t h p r o d u c e r and consumers) range f r o m 1.2 t o 2.4 b i l l i o n d o l l a r s annually (Table 4).

The c u r r e n t d o l l a r e s t i m a t e s of c r o p loss a r e u s e f u l

p r i m a r i l y as i n d i c a t o r s o f t h e magnitudes o f impact.

A f u l l accounting o f t h e

economic mechanisms u n d e r l y i n g a g r i c u l t u r a l p r o d u c t i o n i s r e q u i r e d t o p r o v i d e d e f i n i t i v e estimates o f a g r i c u l t u r a l losses.

Such an assessment s h o u l d i n c l u d e

b o t h annual and p e r e n n i a l c r o p s and t h e a s s o c i a t e d dynamics o f a g r i c u l t u r a l production.

The assessment s h o u l d a l s o i n c l u d e f a c t o r s t h a t a f f e c t p l a n t

response t o 03 such as t h e temporal n a t u r e o f t h e exposure and t h e i n f l u e n c e o f p l a n t w a t e r s t r e s s on exposure-response f u n c t i o n s . SUMMARY

Several l i n e s o f e v i d e n c e l e a d t o t h e c o n c l u s i o n t h a t 03 i s t h e most i m p o r t a n t a i r p o l l u t a n t a f f e c t i n g vegetation i n t h e United States.

A i r monitoring

s t u d i e s have found e l e v a t e d 03 l e v e l s i n many areas and v e g e t a t i o n s t u d i e s have c o n f i r m e d t h a t t h e s e l e v e l s a r e h i g h enough t o impact c r o p y i e l d .

Controlled

f i e l d exposures t o 03 have s u b s t a n t i a t e d t h e i m p a c t o f 03 on c r o p y i e l d and p e r m i t t e d t h e development o f exposure response f u n c t i o n s f o r economic assessments.

U e t a i l e d economic a n a l y s e s have found t h a t 03 causes s i g n i f i c a n t

i m p a c t s on b o t h p r o d u c e r s and consumers.

TABLE 4 E s t i m a t e s o f n a t i o n a l economic consequences o f ozone exposure.

Crops

Annual b e n e f i t s o f control, $ million

A d d i t i o n a l Comments

Reference

53

3 crops: corn, soybeans, and c o t t o n . Two c o r n c u l t i v a r s , t h r e e soybean, two cotton.

$2.2 i n 1980 do1 1 a r s .

Economic e s t i m a t e measured i n terms o f changes i n consumer and producer s u r p l u s e s a s s o c i a t e d w i t h t h e change i n 03.

4 c r o p s : c o r n , soybeans, wheat, and c o t t o n . Two c u l t i v a r s f o r c o r n and c o t t o n , t h r e e f o r soybeans and wheat.

$2.4 i n 1980 do1 1a r s .

Same as Adams and Crocker ( r e f . 53). L i n e a r f u n c t i o n s r e s u l t i n h i g h e r y i e l d l o s s e s and hence h i g h e r economic l o s s e s t i m a t e s . Reported e s t i m a t e ($2.4 b i l l i o n ) i s f o r q u a d r a t i c response f u n c t i o n .

5 crops: corn, soybeans, wheat, c o t t o n , and peanuts. M u l t i p l e c u l t i v a r s o f each c r o p except peanuts.

$1.2 i n 1978 do1 1 a r s

I n a d d i t i o n t o measuring t h e change i n economic s u r p l u s f o r v a r i o u s assumed 03 l e v e l s , t h e a n a l y s i s a l s o i n c l u d e s an e x a m i n a t i o n o f t h e s e n s i t i v i t y o f t h e e s t i m a t e s o f t h e n a t u r e o f t h e demand r e l a t i o n s h i p s used i n t h e model.

55

6 c r o p s : b a r l e y , c o r n , soybeans, c o t t o n , wheat, and sorghum. M u l t i p l e c u l t i v a r s used f o r each c r o p except b a r l e y and g r a i n sorghum; two f o r c o t t o n , t h r e e f o r wheat, t w o f o r c o r n , and n i n e f o r soybeans.

$1.7 i n 1980 do1 1a r s

Consumer s u r p l u s e s t i m a t e d f o r b o t h domestic and f o r e i g n markets; producer s u r p l u s n a t i o n a l l y by r e g i o n . ,The a n a l y s i s i n c l u d e s a range o f economic e s t i m a t e s r e f l e c t i n g changes i n response and 03 d a t a and assumptions.

56

.

.

54

62 REFERENCES

1 2 3 4 5 6 7 8 9 10 11 12 13

14 15 16 17 18 19 20

21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

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.

.

63 37

J. S. Jacobson, i n M. H. Unsworth and 0. P. Ormrod (Eds.),

Effects o f Gaseous A i r P o l l u t i o n i n A g r i c u l t u r e and H o r t i c u l t u r e , B u t t e r w o r t h Scient i f i c , London, 1982, pp. 293-304. 38 R. J. Oshima, J. P. Bennett and P. K. Braegelmann, J. Am. SOC. Hort. Sci. 103 (1978) 348-350. 39 R. J. Oshima, P. K. Braegelmann, R. B. F l a g l e r and R. R. Teso, J. Environ. Qual. 8 (1979) 474-479. 40 J. P. Bennett, R. J. Oshima and L. F. L i p p e r t , Environ. Exp. Bot. 19 (1979) 33-39. 41 S. B. McLaughlin and G. E. Taylor, Science 221 (1981) 167-169. 42 P. J. Temple, 0. C. T a y l o r and L. F. Benoit, J. Environ. Qual. 14 (1985) 55-60. 43 D. M. Olszyk and T. W . T i b b i t t s , P l a n t P h y s i o l . 67 (1981) 539-544. 44 D. T. Tingey, G. L. T h u t t , M. L. Gumpertz and W . E. Hogsett, A g r i c . Environ. 7 (1982) 243-254. 45 H. A. Menser and H. E. Heggestad, Science 153 (1966) 424-425. 46 R. A. R e i n e r t , A. S. Heagle and W . W. Heck, i n J. B. Mudd and T. T. Kozlowski (Eds.), Response o f P l a n t s t o A i r P o l l u t i o n , Academic Press, Inc., New York, 1975, pp. 159-177. 47 D. P. Ormrod, i n M. ti. Unsworth and D. P. Ormrod (Eds.), E f f e c t s o f Gaseous A i r P o l l u t i o n i n A g r i c u l t u r e and H o r t i c u l t u r e , B u t t e r w o r t h S c i e n t i f i c , London, pp. 307-331. 48 A. S. Heagle, W . W . Heck, J. 0. Rawlings and R. B. Philbeck, Crop Sci. 23 (1983) 1184-1191. 49 P. B. Reich and R. G. Amundson, Environ. P o l l u t . ( S e r i e s A) 34 (1984) 345-355. 50 R. J. Oshima, The Impact o f S u l f u r D i o x i d e on Vegetation: A S u l f u r Dioxide-Ozone Response Model, Report, agreement no. A6-162-30, C a l i f o r n i a A i r Resources Board, Sacramento. 51 K. W . F o s t e r , H. Timm, C. K. Labanauskas and R. J. Oshima, J . Environ. Qual 12 (1983) 75-80. 52 A. S. Lefohn and D. T. Tingey, Atmos. Environ. 18 (1984) 2521-2526. 53 R. M. Adam and T. 0. Crocker, i n T. 0. Crocker (Ed.), Economic Perspect i ves on A c i d D e p o s i t i o n Control , B u t t e r w o r t h Pub1 ishers , Boston, 1984, pp. 35-64. 54 R. M. Adams, R. M. Crocker and R. W . Katz, Rev. Econ. S t a t . 66 (1984) 568-575. 55 R. J. Kopp, W. J. Vaughan and M. H a z i l l a , A g r i c u l t u r a l Sector Benefits A n a l y s i s f o r Ozone: Methods E v a l u a t i o n and Demonstration, U.S. Environmental P r o t e c t i o n Agency, Research T r i a n g l e Park, North C a r o l i n a , EPA-450/ 5-84-003, 1984, 56 R. M. Adams, S. A. Hamilton and B. A. McCarl, The Economic E f f e c t s o f Ozone on A g r i c u l t u r e , U.S. Environmental P r o t e c t i o n Agency, C o r v a l l i s , Oregon, EPA-600/3-84-090, 1984.

.

T. Schneider (Editor)/Acidification and its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

65

EFFECTS OF A C I D I C DEPOSITION ON SOIL AND GROUNDWATER J.J.M.

van G r i n s v e n , F.A.M.

d e Haan and W i

van

Riemsdijk

-Department o f S o i l S c i e n c e and P l a n t N u t r i t i o n , A g r i c u l t u r a l U n i v e r s i t y , P.O.

Box 8005,

6700 EC Wageningen.

The f i r s t a u t h o r i s a p p o i n t e d by t h e

Department o f S o i l Science and Geology. ABSTRACT A c i d i c .atmospheric d e p o s i t i o n w i l l r e s u l t i n soil. a c i d i f i c a t i o n , w h i c h may cause s e r i o u s harm t o f o r e s t p r o d u c t i o n . S o i l a c i d i f i c a t i o n i n v o l v e s t h e c h a n g e o f s e v e r a l s o i l p r o p e r t i e s . The d e c r e a s e o f t h e a c i d n e u t r a l i z i n c a p a c i t y i s a s u i t a b l e p a r a m e t e r t o q u a n t i f y s o i 1 a c i d i f i c a t i o n . A decrease! pH and i n c r e a s e d c o n c e n t r a t i o n s o f a l u m i n u m and ammonium as c o m p a r e d t o c o n c e n t r a t i o n s o f c a t i o n i c p l a n t n u t r i e n t s a f f e c t b i o l o g i c a l f u n c t i o n s . The ma n i t u d e s and t i m e s c a l e s o f c h a n g e s i n s o i 1 . c h e m i s t r . y d e p c n d on c a t i o n exc%an e p r o p e r t i e s and t h e n a t u r e and r a t e o f s i l i c a t e weathering. Knowled e about I h e s e . t w o .proce.sses i s a l s o e s s e n t i a l t o e v a l u a t e s t r a t e g i e s t o aba&e acid conditions i n soils. INTRODUCTION S o i l a c i d i f i c a t i o n i s a n a t u r a l process w i c h can be s t r o n g l y enhanced by a t m o s p h e r i c d e p o s i t i o n o f SO*,

NO,

and NHg Enhanced s o i l a c i d i f i c a t i o n due

t o a c i d d e p o s i t i o n i s an i m p o r t a n t example o f s o i l d e g r a d a t i o n because t h e l a n d a r e a i n v o l v e d i s v e r y l a r g e and e f f e c t s on b i o l o g y d e v e l o p v e r y g r a d u a l l y and a r e o f t e n d i f f i c u l t t o d i s t i n g u i s h f r o m n a t u r a l phenomena and e f f e c t s f r o m o t h e r changes i n t h e environment.

Evidence grows t h a t

d e g r a d a t i o n o f s o i l c o n d i t i o n s due t o a c i d d e p o s i t i o n s e r i o u s l y harms f o r e s t p r o d u c t i o n and t h e f u n c t i o n i n g o f v a l u a b l e e c o s y t e m s i n n o r t h and c e n t r a l Europe and t h e n o r t h - e a s t o f t h e N o r t h American c o n t i n e n t . I n t h e absence o f a c l e a r c u t d e f i n i t i o n o f s o i l a c i d i f i c a t i o n s e v e r a l s c i e n t i f i c c o n t r o v e r s i e s a r o s e a b o u t t h e t r u e n a t u r e o f t h i s process and about t h e r e l a t i v e i m p o r t a n c e o f man-induced s o i l a c i d i f i c a t i o n versus n a t u r a l s o i l a c i d i f i c a t i o n . S o i l a c i d i f i c a t i o n can e x e r t i t s e l f i n v a r i o u s ways: by a decrease o f pH o r base s a t u r a t i o n , by an i n c r e a s e i n s o i l a c i d i t y , b y an u n b a l a n c e d a v a i l a b i l i t y o f n u t r i e n t s i n t h e r o o t e n v i r o n m e n t o r by a d e c r e a s e o f t h e a c i d n e u t r a l i z i n g c a p a c i t y (ANC) o f t h e s o i l . F r o m w h i c h a n g l e one w i s h e s t o approach t h e s o i l a c i d i f i c a t i o n process depends on t h e q u e s t i o n t o be answered. Relevant q u e s t i o n s are:

-

To what e x t e n t i s a c i d d e p o s i t i o n d e t e r i o r a t i n g s o i l c o n d i t i o n s now,

and

w i l l i t d o i n t h e f u t u r e , and what a r e t h e e f f e c t s on ecosystems i n g e n e r a l and f o r e s t g r o w t h i n p a r t i c u l a r ?

-

Which s i t u a t i o n s need a m e l i o r a t i o n and how s h o u l d t h i s a m e l i o r a t i o n o f s o i l

66

c o n d i t i o n s be b r o u g h t about? To a n s w e r t h e s e q u e s t i o n s we need a t h o r o u g h u n d e r s t a n d i n g o f c h e m i c a l i n t e r a c t i o n s i n t h e s o i l r e l a t e d t o t h e a c i d i f i c a t i o n process.

Forest s o i l s

i n g e n e r a l have a g r e a t c a p a b i l i t y t o d e l a y e f f e c t s o f a c i d i c d e p o s i t i o n due t o t h e presence o f a l a r g e ,

mainly bio-organic,

exchange complex.

However

t h e u l t i m a t e p r o c e s s f o r a c i d n e u t r a l i z a t i o n and supply o f p l a n t n u t r i e n t s i n ( u n - f e r t i l i z e d ) s o i l s i s d i s s o l u t i o n o f s i l i c a t e minerals.

Compared t o

current deposition rates t h e capacity o f s i l i c a t e minerals t o neutralize acid i s nearly infinite.

However t h e r a t e s o f d i s s o l u t i o n a r e f a r more i m p o r t a n t

as t h e y seem t o b e s i m i l a r t o c u r r e n t d e p o s i t i o n r a t e s . E x c h a n g e r e a c t i o n s and m i n e r a l d i s s o l u t i o n need

t o be u n d e r s t o o d t o e v a l u a t e p r e s e n t and f u t u r e

e f f e c t s o f a c i d d e p o s i t i o n on s o i l and t o develop abatement s t r a t e g i e s .

S O I L ACIDIFICATION: THE CONCEPT OF A C I D NEUTRALIZING CAPACITY The s o i l m a t r i x g e n e r a l l y c o n s i s t s o f a l a r g e b u l k o f i n e r t q u a r t z i n w h i c h v a r i o u s amounts o f c l a y m i n e r a l s , and i r o n , primar.y

amorphous ( h y d r t o x i d e s o f aluminum

m i n e r a l s and o r g a n i c m a t t e r a r e present. C l a y m i n e r a l s and

o r g a n i c m a t t e r have predominantly n e g a t i v e l y charged surfaces ( p a r t l y ) n e u t r a l i z e d by c a t i o n s .

I f s t r o n g a c i d e n t e r s t h e s o i l i t can r e a c t w i t h t h e

s o i l m a t r i x i n v a r i o u s ways:

1 ) If t h e p r o t o n s do n o t r e a c t w i t h s o i l c o n s t i t u e n t s a pH decrease w i l l t a k e p l ace.

2 ) The p o s i t i v e l y charged p r o t o n s can exchange a g a i n s t base c a t i o n s (Na,

K,

Ca and Mg) bound t o c l a y m i n e r a l s o r o r g a n i c m a t t e r . The pH decrease w i l l b e l e s s t h a n i n c a s e ( 1 ) and w i l l b e i n s i g n i f i c a n t

'

when

the

proton

i n p u t i s n e g l i g i b l e compared t o t h e t o t a l amount o f base c a t i o n s bound t o c l a y m i n e r a l s and o r g a n i c m a t t e r .

CI-C~

+ ZH+ --->

CI-H~

+ Ca2+

3 ) The p r o t o n s can r e a c t w i t h p r i m a r y m i n e r a l s o r (hydr)oxides. b e bound i n c a r b o n i c a c i d , w a t e r brought i n t o solution.

C ~ C O+ ~ZH+

--->

Protons w i l l

o r s i l i c i c a c i d and c a t i o n s w i l l b e

T h i s can b e e x a m p l i f i e d b,y t h e f o l l o w i n g r e a c t i o n s : Ca2+

+

~ 2 ~ 0 3

Al(OH)3 + 3H+ --->

A13+ + 3H20

Mg2Si04 + 4H+ --->

2Mg2+ + H4Si04

The pH d e c r e a s e w i l l b e l e s s t h a n i n (1). I f t h e m i n e r a l i s r e l a t i v e l y

67 reactive,

as i n t h e c a s e o f CaC03 t h e pH w i l l r e m a i n a p p r o x i m a t e l y

constant,

as l o n g as t h e m i n e r a l i s p r e s e n t .

I f t h e mineral i s very

u n r e a c t i v e , t h e i n c r e a s e i n pH w i l l b e n o t i c e a b l e on1.y i f t h e r e s i d e n c e t i m e o f t h e p e r c o l a t i n g s o i l s o l u t i o n i s long. The above r e a c t i o n s problem.

i l l u s t r a t e the complexity o f t h e s o i l a c i d i f i c a t i o n

D e f i n i t i o n o f s o i l a c i d i f i c a t i o n as a d e c r e a s e o f s o i l pH i s

o b v i o u s 1 . y t o o n a r r o w , a l t h o u g h f r o m an e c o l o g i c a l p o i n t o f v i e w i t m i g h t s u f f i c e because an unchanged pH g e n e r a l l y i n d i c a t e s unchanged c o n d i t i o n s f o r p l a n t growth.

R e c e n t l y t h e d e f i n i t i o n o f s o i l a c i d i f i c a t i o n as a decrease o f

t h e a c i d n e u t r a l i z i n g c a p a c i t y (ANC) was i n t r o d u c e d ( r e f . 1 a n d 2). The ANC o f a s o i l i s d e f i n e d as t h e sum o f c a t i o n s m i n u s t h e sum o f s t r o n g a c i d anions, expressed as t h e i r p o t e n t i a l t o consume o r produce p r o t o n s above a pH o f 3: 2(Mg0) + 2(K20) + Z(Na20) + 2(Mn0) +

p205)

-

HC1

-

oxalate

The t e r m s correspond t o t h e t o t a l amounts o f t h e r e s p e c t i v e e l e m e n t s i n an i n o r g a n i c b u l k s o i l s a m p l e , e x p r e s s e d eg. a s c a p a c i t y t o consume m o l e s o f protons per kg o f a

b u l k s o i l . Some consequences o f t h e above d e f i n i t i o n a r e

t h a t any i n t r o d u c t i o n o f s t r o n g a c i d ,

eg. H2SO4,

w i l l d e c r e a s e t h e ANC.

However when t h e s t r o n g a c i d would pass t h e s o i l u n n e u t r a l i z e d t h e ANC would r e m a i n unchanged. I f a weak a c i d w o u l d be i n t r o d u c e d t o t h e s o i l , eg. H2CO3 o r o r g a n i c a c i d s , t h e ANC w o u l d n o t be c h a n g e d u n l e s s t h e s e a c i d s m o b i l i z e c a t i o n s w h i c h a r e subsequently leached f r o m t h e s o i l system f o r w h i c h t h e ANC was defined.

As i n most areas i n n o r t h and c e n t r a l Europe and t h e n o r t h - e a s t

o f N o r t h America p r e c i p i t a t i o n exceeds e v a p o t r a n s p i r a t i o n ,

leaching ofcations

f r o m t h e s o i l , and c o n s e q u e n t l y s o i l a c i d i f i c a t i o n a c c o r d i n g t o t h e above mechanism, i s v e r y common. Changes o f ANC can he expressed i n kmol.ha-'.yr-l. NATURAL AND ENHANCED S O I L ACIDIFICATION

I n a clean p r e - i n d u s t r i a l s i t u a t i o n t h e r e a r e two sources o f protons i n p u t t o s o i l , c a r b o n i c a c i d (H2C03) and o r g a n i c a c i d s . C a r b o n i c a c i d w i l l o n l y d i s s o c i a t e p r o t o n s a t pH v a l u e s a b o v e 5.

S o i l a c i d i f i c a t i o n due t o

c a r b o n i c a c i d t h e r e f o r e i s o f p a r t i c u l a r i n t e r e s t i n s o i l s w i t h near n e u t r a l pH, i n c l u d i n g t h o s e r i c h i n c a r b o n a t e m i n e r a l s . The o v e r a l l r e a c t i o n i n calcareous s o i l s i s :

68

CaC03

+

C02 + H20 --->

Ca2'

+ 2HCO3-

The n e t e f f e c t w i l l be l e a c h i n g o f Ca f r o m t h e s o i l p r o f i l e and t h u s a decrease o f ANC. kmol.ha-'.yr-l,

R e s u l t i n g s o i l a c i d i f i c a t i o n r a t e s can be as h i g h as 10-20

as compared t o 4 kmol.ha-'.yr-l

due t o a c i d d e p o s i t i o n i n t h e

more exposed areas i n t h e Netherlands, FRG and CSSR. I f a s o i l i s d e c a l c i f i e d and i s c o v e r e d by a v e g e t a t i o n ,

biological

a c t i v i t y w i l l produce o r g a n i c acids, which can d i s s o c i a t e and cause pH values l e s s t h a n 4.

Furthermore t h e organic anions can m o b i l i z e c a t i o n s which a r e

subsequently leached from t h e s o i l . T h i s may r e s u l t i n a decrease o f ANC i n t h e o r d e r o f 0.1 t o 0.5 k m o l . h a - l . y r - l

( r e f . 3).

Vegetation under u n f e r t i l i z e d c o n d i t i o n s tendslto t a k e up more c a t i o n s than anions. F o r c h a r g e b a l a n c e p u r p o s e s t h i s d i f f e r e n c e i s compensated b y an e x c r e t i o n o f p r o t o n s from t h e r o o t s . R e s u l t i n g s o i l a c i d i f i c a t i o n i s o f s i m i l a r magnitude as t h a t due t o o r g a n i c acids. Regular

removal

acidification,

of

vegetation

or

l i t t e r by man w i l l

increase

soil

due t o t h e c o n c u r r e n t n e t r e m o v a l o f c a t i o n s f r o m t h e

i n o r g a n i c s o i l system. Removal o f f o r e s t l i t t e r f o r use i n a g r i c u l t u r e , which was common on p o o r s o i l s u n t i l t h e b e g i n n i n g o f t h i s c e n t u r y , c a n i n c r e a s e s o i l a c i d i f i c a t i o n w i t h 0.1 t o 1, modern a g r i c u l t u r e harvests) w i t h 2 t o 3 kmol.ha-l.yr-l

( f e r t i l i z e r use,

high

( r e f . 4).

Wet and d r y d e p o s i t i o n o f a c i d i c o r p o t e n t i a l l y a c i d i c s u b s t a n c e s c a n i n c r e a s e s o i l a c i d i f i c a t i o n by 1 t o 2 kmol.ha-'.yr-l north-west o f N o r t h America and by 2 t o 8 kmol.ha-l.yr-'

i n Scandinavia and t h e i n west and c e n t r a l

Europe. CHEMICAL CHARACTERISTICS OF ACIDIFIED SOILS D e f i n i t i o n o f s o i l a c i d i f i c a t i o n as a decrease o f t h e ANC i s unambiguous, b u t does n o t p r o v i d e e c o l o g i c a l l y u s e f u l i n f o r m a t i o n .

I n t h i s c h a p t e r we w i l l

d e s c r i b e some t y p i c a l chemical f e a t u r e s o f n a t u r a l l y and a n t r o p o g e n i c a l l y a c i d i f y i n g soi 1s. I n t e r e s t i n g parameters a r e c o n c e n t r a t i o n s o f a number o f s o l u t e s i n t h e s o i l s o l u t i o n e s p e c i a l l y o f H, commonly e x p r e s s e d as pH ( - l o g ( H + ) ) , h e r e a f t e r adressed as M,

and A l .

Ca+Mg,

Apart f r o m t h e c o n c e n t r a t i o n s t h e f l u x e s o f

these components f r o m t h e s o i l t o t h e groundwater a r e o f i n t e r e s t too. I n a c a r b o n a t e h o l d i n g s o i l t h e d o m i n a n t a n i o n w i l l b e HC03-, d o m i n a t i n g c a t i o n w i l l b e M,

t h e pH w i l l b e a b o u t 7 ,

i n s i g n i f i c a n t . The e q u i v a l e n t l e a c h a t e f l u x (kmol.ha-'.yr-l)

the

A1 w i l l b e of

Ca (and

HC03) w i l l e q u a l t h e a c i d i f i c a t i o n r a t e . C o n c e n t r a t i o n s a l s o depend on t h e

d i f f e r e n c e b e t w e e n p r e c i p i t a t i o n and e v a p o t r a n s p i r a t i o n . The s m a l l e r t h e d i f f e r e n c e , t h e h i g h e r c o n c e n t r a t i o n s t e n d t o be. The d i f f e r e n c e b e t w e e n p r e c i p i t a t i o n and e v a p o t r a n s p i r a t i o n i n c r e a s e s g o i n g f r o m c o n i f e r o u s f o r e s t t o d e c i d u o u s f o r e s t t o g r o u n d v e g e t a t i o n (eg. h e a t h l a n d ) t o b a r e s o i l . t h e same range a c i d atmospheric d e p o s i t i o n t e n d s t o decrease.

In

Discussion f r o m

h e r e on w i l l d e a l w i t h a c i d s o i l s (pH<61 w h i c h a r e n o t used f o r a g r i c u l t u r e . Although

s o i l a c i d i f i c a t i o n i s a r e l e v a n t process i n a g r i c u l t u r a l s o l l s , i t

p o s e s n o p r o b l e m a s a d e q u a t e l i m i n g i s common p r a c t i c e .

I n fact

i n

a g r i c u l t u r e t h e ANC o f t h e s o i l may r e m a i n c o n s t a n t o r even i n c r e a s e due t o a p p l i c a t i o n o f l i m e and some f e r t i l i z e r s as ANC c o n t r i b u t o r s . I n n a t u r a l l y acid s o i l s t h e anions i n t h e leachate are mainly organic, w h i l e c o n c e n t r a t i o n s o f A1 c a n r a n g e b e t w e e n 30 a n d 1 0 0 m m ~ l . m - ~ . C o n c e n t r a t i o n s w i t h i n t h e r o o t z o n e a r e t h e o v e r a l l r e s u l t o f a complex s e r i e s o f processes. n u t r i e n t s (eg.

S o i l s c o v e r e d by a v e g e t a t i o n a r e i n v o l v e d i n a c y c l e o f NH4,

NO3, M a n d K) w h i c h a r e m o b i l i z e d a t t h e s u r f a c e b y

biodegradation o f organic m a t e r i a l ,

mineralization,

and g r a d u a l l y t a k e n up

again by t h e r o o t s from t h e p e r c o l a t i n g s o i l solution.

The e f f e c t s o f

a t m o s p h e r i c d e p o s i t i o n on t h e s o i l s o l u t i o n c o m p o s i t i o n i s superimposed on t h e e f f e c t s o f t h e biocycle. A t m o s p h e r i c d e p o s i t i o n o f a c i d i c o r p o t e n t i a l l y a c i d i c substances w i l l i n c r e a s e t h e t o t a l amount o f s o l u t e s i n t h e s o i l . G e n e r a l l y c o n c e n t r a t i o n s o f

SO4 and NO3 w i l l increase. The l a t t e r depends on whether d e p o s i t e d NO3 o r NH4 i s t a k e n up by t h e v e g e t a t i o n .

I n t h e e a s t o f t h e N e t h e r l a n d s and t h e n o r t h -

west o f FRG d e p o s i t i o n o f NH4, up t o 2 kmol.ha-l.yr-’

o f NO3. The NH4 i n many cases i s ,

n e x t t o a d e p o s i t i o n o f 1 kmol.ha-’.yr-’ least partly,

n i t r i f i e d i n the soil,

i s common i n woodlands, at

leading t o increased s o i l a c i d i f i c a t i o n .

I f a l l d e p o s i t e d NH3 i s t a k e n u p t h e r e w i l l b e n o a c i d i f y i n g e f f e c t , i f a l l

d e p o s i t e d NH3 i s n i t r i f i e d and n o t t a k e n up s o i l a c i d i f i c a t i o n w i l l be 1 m o l e p e r 1 m o l e o f d e p o s i t e d NH3. I n an e a r l y s t a g e o f s o i l a c i d i f i c a t i o n t h e g e n e r a t e d a c i d w i l l b e n e u t r a l i z e d by d i s s o l u t i o n o f Ca, K , Na and Mg. W i t h progressing s o i l

acidification,

e s p e c i a l l y when a t h i g h r a t e s ,

acid

deposition w i l

be n e u t r a l i z e d by d i s s o l u t i o n o f A l . The c a p a c i t y o f t h e s o i l

t o produce A1

s n e a r l y i n f i n i t e : compared t o base c a t i o n s A1 i s an abundant

c o n s t i t u e n t o f t h e s o i l m a t r i x . Aluminum can be t o x i c , c o n c e n t r a t i o n i s h i g h c o m p a r e d t o M.

e s p e c i a l l y when t h e

The same i s t r u e f o r NH4, when t h e

c o n c e n t r a t i o n i s h i g h c o m p a r e d t o t h a t o f K and Mg. T o x i c e f f e c t o f A1 and

70

NH4 i s d i m i n i s h e d i n t h e s u r f a c e s o i l by m i n e r a l i z a t i o n o f base c a t i o n s . Absolute concentrations o f A l , d e p o s i t i o n rate.

SO4, NO3 and NH4 depend on v e g e t a t i o n t y p e and

F o r Dutch f o r e s t s w i t h d e p o s i t i o n r a t e s o f 2 (deciduous) t o

3 ( c o n i f e r o u s ) kmol.ha-l.yr-l, amount t o 2 and 4, o f

i o n i c e q u i v a l e n t c o n c e n t r a t i o n s o f A1 c a n

SO4 1 and 2 and o f NO3 1 and 2 m r n ~ l . m - ~ , f o r d e c i d u o u s

and c o n i f e r o u s f o r e s t s r e s p e c t i v e l y . C o n c e n t r a t i o n s o f NH4 i n s o l u t i o n s O f f o r e s t s o i l s a r e g e n e r a l l y low.

Under h e a t h l a n d i o n i c e q u i v a l e n t

c o n c e n t r a t i o n s o f NH4 c a n b e a s h i g h a s 0.5

mm01.m-~ due t o l e s s

nitrification,

w h i c h i s s t i l l comparably l o w compared t o c o n c e n t r a t i o n s o f ,

f o r example,

NO3 i n f o r e s t s o i l s .

This difference

results from

low

e v a p o t r a n s p i r a t i o n and d e p o s i t i o n . A b s o l u t e c o n c e n t r a t i o n s i n , g e n e r a l l y c o n i f e r o u s , f o r e s t s i n S c a n d i n a v i a w i l l be up t o t e n t i m e s l o w e r due t o l o w e r d e p o s i t i o n r a t e s and h i g h e r p r e c i p i t a t i o n surpluses. EFFECTS ON GROUNDWATER AND D R I N K I N G WATER S o i l l e a c h a t e s r i c h i n NO3, reach deeper groundwater.

SO4,

A1 and p o s s i b l y NH4,

w i l l eventually

F o r example c o n c e n t r a t i o n s o f ’ N 0 3 i n s o i l w a t e r and

s h a l l o w g r o u n d w a t e r under Dutch woodland s o i l s range between 50 and 200 mg.1-l ( r e f . 5).

These c o n c e n t r a t i o n s a r e a l a r m i n g as t h e y e x c e e d t h e c u r r e n t

d r i n k i n g w a t e r s t a n d a r d s o f 50 mg.1-1

and a r e comparable t o c o n c e n t r a t i o n s

under h e a v i l y manured farmland. However t h e v e l o c i t y o f t h e n i t r a t e f r o n t under f o r e s t (about 0.5

m.yr-l)

i s l o w e r t h a n under f a r m l a n d (1 m.jr-’),

t o a l o w e r p r e c i p i t a t i o n surplus.

due

C u r r e n t d r i n k i n g w a t e r s t a n d a r d s f o r NO3

l i k e l y w i l l be aggravated i n t h e n e a r f u t u r e .

Drinking water stations i n t h e

N e t h e r l a n d s a r e c o m m o n l y l o c a t e d on s a n d y s e d i m e n t s u n d e r f o r e s t i n a r e a s w i t h h i g h ammonia d e p o s i t i o n . Due t o d e n i t r i f i c a t i o n t h e NO3 c o n c e n t r a t i o n i n g r o u n d w a t e r may f u r t h e r d e c r e a s e when m o v i n g down. H o w e v e r , l o w o r g a n i c C c o n t e n t s and l o w pH may l i m i t d e n i t r i f i c a t i o n rates.

H i g h NO3 c o n c e n t r a t i o n s i n g r o u n d w a t e r may a l s o

c a u s e o x i d a t i o n o f s u l f i d e c o n t a i n i n g s e d i m e n t s and e x p l a i n o c c a s i o n a l l y reported

l o w pH v a l u e s a t g r e a t e r d e p t h s (N1O m) ( r e f . 5).

R e c e n t l y one d r i n k i n g w a t e r pumping s t a t i o n has been c l o s e d a l r e a d y i n an area i n t h e N e t h e r l a n d s w i t h h i g h NO3 c o n c e n t r a t i o n s due t o e x c e s s i v e manure a p p l i c a t i o n . Groundwater q u a l i t y n e a r pumping s t a t i o n s i s t h r e a t e n e d and w i l l be t h r e a t e n e d , a l s o under f o r e s t areas. S u l p h a t e c o n c e n t r a t i o n s i n s o i l w a t e r under woodlands due t o a c i d d e p o s i t i o n ,

5 0 - 1 0 0 mg.l-’,

a p p r o a c h t h e D u t c h d r i n k i n g w a t e r s t a n d a r d o f 100 mg.1-’

also gradually

(EC 2 5 0 mg.1-’).

s p e c i a l p r o b l e m i s posed b,y d r i n k i n g w a t e r f r o m p r i v a t e w e l l s ,

A

e i t h e r f o r use

b y c a t t l e o r b y man. P r o b l e m s w i t h NO3 f o r c a t t l e h a v e b e e n r e p o r t e d i n t h e

Netherlands.

R e c e n t l y a r e l a t i o n was s u g g e s t e d b e t w e e n t h e i n c r e a s i n g

71

o c c u r r e n c e o f s e n i l e d e m e n t i a and i n c r e a s e d A1 l e v e l s i n d r i n k i n g w a t e r f r o m p r i v a t e w e l l s i n t h e UK.

KEY PROCESSES AND CRITICAL PARAMETERS I n o r d e r t o o b t a i n m o r e i n s i g h t i n t h e p r e s e n t and f u t u r e e f f e c t s o f a c i d i c d e p o s i t i o n on t h e s o i l c h e m i s t r y some key s o i l c h e m i c a l processes w i l l be d i s c u s s e d b r i e f l y . S u r f a c e s o i l s o f f o r e s t g e n e r a l l y have a l a r g e o r g a n i c exchange complex, w i t h e q u i v a l e n t c a p a c i t i e s (CEC) u p t o 1 0 0 mmol.kg-l.

Cation equivalent

exchange c a p a c i t y f o r t h e r o o t e d s o i l p r o f i l e (0.3-1

converted t o areal

u n i t s , r a n g e s f r o m 200 t o 500 kmol.ha-',

m),

w h i c h i s c o n s i d e r a b l e compared t o

d e p o s i t i o n r a t e s o f 2 t o 8 kmol.ha-l.yr-1.

Such a l a r g e e x c h a n g e c a p a c i t y

s t r o n g l y b u f f e r s c o n c e n t r a t i o n s o f a l l c a t i o n s i n t h e s o i l s o l u t i o n . I n an e a r l y s t a g e o f a c i d i c d e p o s i t i o n a C o n s i d e r a b l e p o r t i o n o f t h e exchange complex w i l l

b e o c c u p i e d by b a s e c a t i o n s .

i n d i c a t e d as base s a t u r a t i o n v a l u e (6s).

This f r a c t i o n i s generally

P r o t o n s w i l l a t f i r s t be exchanged

a g a i n s t t h e s e b a s e c a t i o n s . 8 ~ a r e s u l t t h e pH i n t h e s o i l s o l u t i o n r e m a i n s r e l a t i v e l y constant,

w h i l e c o n c e n t r a t i o n s o f base c a t i o n s a r e i n c r e a s e d and

a r e leached f r o m t h e s o i l . I n o r d e r t o l o w e r an i n i t i a l s o i l w i t h a n e q u i v a l e n t C E C o f 400 kmol.ha-', d e p o s i t i o n a t a r a t e o f 3 kmol.ha-l.yr-l

BS o f 30% t o 10% i n a

27 y e a r s o f a c i d d e p o s i t i o n

w o u l d be necessary, assuming no I n advanced s t a g e s o f s o i l

r e s u p p l y o f bases f r o m a d d i t i o n a l processes.

BS o f t e n l i e s below lo%, w h i l e t h e r e m a i n d e r o f t h e CEC i s H and A l . I n o r d e r t o r e s t o r e t h e i n i t i a l BS f o r e s t s o i l s c o u l d

acidification the occupied by

be l i m e d o r d e p o s i t i o n r a t e s c o u l d be lowered. I n t h e l a t t e r case n a t u r a l r e s u p p l y o f bases ( t o b a l a n c e n e t l o s s ) w o u l d o c c u r by m i n e r a l w e a t h e r i n g , w h i c h w i l l be d i s c u s s e d l a t e r i n t h i s chapter. To b r i n g t h e BS f r o m 10 t o 30% 400 kg CaCO3 p e r h a would b e needed.

N a t u r a l r e s u p p l y by m i n e r a l w e a t h e r i n g

a t a common r a t e o f 0.5 k m o l . h a - l . y r - l

w o u l d t a k e a t l e a s t 160 y e a r s . These

examples c l e a r l y i l l u s t r a t e t h e d e l a y i n g e f f e c t o f t h e c a t i o n exchange c o m p l e x on a d v e r s e e f f e c t s o f a c i d i c d e p o s i t i o n and b e n e f i c i a l e f f e c t s o f lowering

t h e d e p o s i t i o n rate.

In a l l temporarily,

cases t h e exchange complex w i l l

prevent t h e occurrence o f

e x t r e m e l y l o w pH values and a s s o c i a t e d h i g h c o n c e n t r a t i o n s o f

A l . Such l o w pH c o n d i t i o n s c a n p r e v a i l a f t e r d r y p e r i o d s i n summer, when accumulated d r y d e p o s i t i o n i s washed, a l l a t once, i n f i l t r a t e s i n t h e soil.

f r o m t h e f o r e s t canopy and

A l s o a c i d p u l s e s may o c c u r a t t h e s t a r t o f snowmelt

o r r i g h t a f t e r a d r y period.

72 A second c r u c i a l process i s m i n e r a l weathering,

which i s t h e d i s s o l u t i o n

o f p r i m a r y and secondary s o i l minerals. The d r i v i n g f o r c e f o r weathering i s t h e a t t a c k o f t h e m i n e r a l surfaces by protons. P r i m a r y m i n e r a l s a r e g e n e r a l l y alumino-silicates,

t h a t c o n t a i n s m a l l amounts o f b a s e c a t i o n s i n t h e i r

c r y s t a l s , l i k e eg. m i c r o l i n e (Na), a l b i t e and m u s c o v i t e (K), a n o r t h i t e and p l a g i o c l a s e (Ca), b i o t i t e (Ca and Mg) etc. Secondary m i n e r a l s a r e residues of i n c o m p l e t e d i s s o l u t i o n o f p r i m a r y minerals, o r m i n e r a l s newly formed f r o m t h e

I T

I

Fi 1. T h e o r e t i c a l r e l a t i o n s i between t h e r a t i o o f c o n c e n t r a t i o n s o f base c a p i o n s ( M 2 + ) and a l u m j n u m PAf3 tl i n s o j l s o l u t i o n as a f u n c t i o n o f depth. The e f f e c t o f i n c r e a s i n t h e d i s s o l t i o r a t e o f b a s e c a t i o n s f r o m t h e m i n e r a j p h p s e . f r o 9 0.5 ($9.) t o 1.0 [ -! kmo1.ha-l.yr-1 i s demonstrated f o r s o i l l a c i d i f i c a t i o n r a t e s o f 4 ( I ) and 2 (11) kmol.ha-l.yr-1. I t i s assumed t h a t m i n e r a l w e a t h e r i n g i s t h e o n l y a c i d n e u t r a l i z i n g p r o c e s s and t h a t , besides t h e base c a t i o n s aluminum i s t h e o n l y d i s s o l v i n g ion. f h e p r e s e n t r a t i o s between concentrat?ons o f M 2 + and A13t in t h e f i e l d (+) a r e c l o s e t o t h e presumably c r i t i c a l value o f 1 (----).

73

r e a c t i o n p r o d u c t s o f d i s s o l u t i o n o f p r i m a r y minerals. The t w o mainlgroups

of

secondary m i n e r a l s a r e c l a y m i n e r a l s , w h i c h i n f a c t a r e a s p e c i a l group o f alumino-si licates,

and o x i d e s and h y d r o x i d e s o f aluminum and i r o n . Sec0ndar.y

m i n e r a l s g e n e r a l l y have l a r g e s u r f a c e areas and exchange c a p a c i t i e s . M i n e r a l d i s s o l u t i o n i s t h e p r i m a r y s o u r c e o f b a s e c a t i o n s and p l a n t n u t r i e n t s i n n a t u r a l systems.

The p r o p o r t i o n o f secondary m i n e r a l s i n t h e s o i l s t r o n g l y

v a r i e s and can amount t o s e v e r a l t e n s o f percentages, depending on rock t y p e and g e o l o g i c a l h i s t o r y . M i n e r a l w e a t h e r i n g c a n be c h a r a c t e r i z e d by ( 1 ) t h e c a p a c i t y t o consume p r o t o n s and t o p r o d u c e b a s e c a t i o n s and A1 and ( 2 ) t h e dissolution rate,

( 3 ) t h e s t o i c h i o m e t r y , w h i c h g i v e s t h e n a t u r e and t h e

r e l a t i v e occurrence o f t h e d i s s o l v e d ions. The c a p a c i t . y o f w e a t h e r i n g t o consume p r o t o n s i s v e r y l a r g e . a v e r a g e s o i l w i t h 20% s i l i c a t e m i n e r a l s , b u f f e r i n g c a p a c i t y a p p r o x i m a t e l y i s 20.000

and a r o o t z o n e o f 0.5

kmol.ha-l.

F o r an

m, t h e

C a p a c i t i e s t o produce

base c a t i o n s a r e a l s o v e r y large. T,ypical i o n i c e q u i v a l e n t p o o l s f o r p o d z o l i c s o i l s a r e 200 t o 400 k m o l Ca o r Mg, 1000 k m o l Na o r K and 10.000 t o 20.000 k m o l A1 p e r ha. The d i s s o l u t i o n r a t e i s a f a r more i m p o r t a n t parameter t h a n t h e c a p a c i t y f o r m i n e r a l weathering. kmol.ha-l.yr-'

I n the field,

weathering

r a t e s o f 0.5

to 5

(base c a t i o n s + A l ) a r e measured i n chemical balance s t u d i e s

( r e f . 2 and 6). H i g h w e a t h e r i n g r a t e s c o r r e s p o n d t o s i t u a t i o n s w i t h h i g h a c i d i f i c a t i o n r a t e s and,

f o r acid soils,

w i t h h i g h f r a c t i o n s o f aluminum i n

t h e d i s s o l v e d i o n s . I n g e n e r a l t h e l a r g e r p a r t o f p r o t o n p r o d u c t i o n due t o a c i d d e p o s i t i o n i s consumed i n s o i l ,

s u g g e s t i n g t h a t p r o t o n consumption r a t e s

a r e s u f f i c i e n t l y h i g h t o m e e t p r e s e n t d e p o s i t i o n r a t e s . However, o f m o r e concern a r e t h e r a t e s o f base c a t i o n weathering:

these d e t e r m i n e whether t h e

BS, w h i c h i s t h e r e a d i l y a v a i l a b l e p o o l o f c a t i o n i c p l a n t n u t r i e n t s w i l l decrease, i n c r e a s e o r remain constant.

I f t h e r a t e o f exchange and subsequent

l e a c h i n g o f base c a t i o n s i s l a r g e r t h a n t h e r a t e o f r e s u p p l y b y m i n e r a l w e a t h e r i n g t h e p o o l w i l l become s m a l l e r , i f i t i s s m a l l e r t h e p o o l w i l l i n c r e a s e i f the,y a r e e q u a l t h e p o o l w i l l

remain constant.

Dissolution

k i n e t i c s o f p r i m a r y m i n e r a l s a r e s t i l l n o t s u f f i c i e n t l y understood t o p r e d i c t weathering rates i n f i e l d situations.

It i s g e n e r a l l y

accepted t h a t

w e a t h e r i n g r a t e s i n c r e a s e w i t h d e c r e a s i n g pH and r e a c t i v e s u r f a c e area,

and

decrease w i t h i n c r e a s i n g a c c u m u l a t i o n o f d i s s o l v e d i o n s i n t h e s o i l s o l u t i o n . Theoretically,

w e a t h e r i n g r a t e s under d i f f e r e n t f i e l d c o n d i t i o n s may v a r y by

a f a c t o r o f 10 t o 100. High w e a t h e r i n g r a t e s can occur d u r i n g s h o r t - l a s t i n g pH d r o p s (<3!) o r e x c e s s i v e f l u s h i n g o f t h e s o i l s o l u t i o n ( d i l u t i o n ) . The amount o f d i s s o l v e d b a s e c a t i o n s and a l u m i n u m f r o m t h e o v e r a l l

74 weathering reaction (the reaction stoichiometry)

i s important as i t

d e t e r m i n e s t h e a b s o l u t e c o n c e n t r a t i o n o f A1 a n d i t s r a t i o t o t h e c o n c e n t r a t i o n o f M, w h i c h a r e b o t h i m p o r t a n t p a r a m e t e r s w i t h r e s p e c t t o damage t o t h e v e g e t a t i o n . The f r a c t i o n o f a l u m i n u m , w h i c h d i s s o l v e s f r o m s i l i c a t e m i n e r a l s , t e n d s t o be h i g h a t l o w pH and f o r h i g h a c i d l o a d i n g s , b u t

w i l l g r a d u a l l y decrease w i t h i n c r e a s i n g r e s i d e n c e t i m e s o f s o i l s o l u t i o n s . The u n d e r l y i n g m e c h a n i s m i s n o t y e t c l e a r . I f t h e f r a c t i o n o f d i s s o l v i n g aluminum decreases w i t h d e c r e a s e d a c i d l o a d i n g ,

t h e r a t i o between

c o n c e n t r a t i o n s o f A1 and M w i l l e v e n t u a l l y i m p r o v e when d e p o s i t i o n r a t e s would be l o w e r e d ( f i g u r e 1). Soi 1s generally contain several

p e r c e n t s o f amorphous aluminum-

(hydr)oxides, which could dissolve r e l a t i v e l y f a s t a f t e r a h i g h i n p u t o f protons. H i g h i n i t i a l aluminum c o n c e n t r a t i o n s c o u l d a l s o r e s u l t f r o m c o m p l e t e (congruent) d i s s o l u t i o n o f mineral crystals. Al(OH)3 + 3H+

--->

A13+ + 3H20

KA13Si3010(OH)2 + 10H'

--->

K+

+ 3A13+ 3H4Si04

I n t h e c o u r s e o f t i m e A1 c o u l d s l o w l y r e p r e c i p i t a t e as a h y d r o x i d e , g r a d u a l l y r e l e a s i n g p r o t o n s i n s o l u t i o n a g a i n , w h i c h w i l l now b e consumed b y b a s e c a t i o n weathering from primary minerals. A13+

+ 3H20 --->

Al(OH)3 + 3H'

KA1 3Si3010(OH)2 + H+

+1.5H20

--->

K+ + 1.5A1 p s i 205(OH)4

The n e t r e s u l t o f t h e w e a t h e r i n g r e a c t i o n i s an i n c o m p l e t e ( i n c o n g r u e n t ) d i s s o l u t i o n o f a p r i m a r y m i n e r a l . By d i s s o l u t i o n o f a l u m i n u m - h y d r o x i d e o r t e m p o r a r i l y c o n g r u e n t d i s s o l u t i o n o f p r i m a r y m i n e r a l s t h e s o i l has a mechanism t o q u i c k l y consume h i g h l o a d s o f protons. A t h i r d p r o c e s s w h i c h can be c r i t i c a l i s n i t r i f i c a t i o n . N i t r i f i c a t i o n i s i m p o r t a n t i n s i t u a t i o n s w i t h h i g h d e p o s i t i o n o f NH3, w h i c h o c c u r i n a r e a s w i t h i n t e n s i v e animal husbandry ( b i o i n d u s t r y ) , f o r example i n t h e e a s t e r n p a r t o f t h e N e t h e r l a n d s and t h e n o r t h - w e s t o f t h e FRG.

I n contradiction w i t h

g e n e r a l e x p e r i e n c e n i t r i f i c a t i o n i n f o r e s t s o i l s a l s o t a k e s p l a c e a t pH v a l u e s b e l o w 4,

as i n d i c a t e d by h i g h l e a c h a t e f l u x e s o f

d e p o s i t e d m a i n l y as NH3.

NO3 when n i t r o g e n i s

A f a i r a v a i l a b i l t y o f b a s e c a t i o n s seems a

prerequisite f o r nitrification.

75

SOME CONCLUSIVE REMARKS S o i l a c i d i f i c a t i o n i s a complex process which w i l l a f f e c t v a r i o u s s o i l parameters.

D e f i n i t i o n o f s o i l a c i d i f i c a t i o n as a d e c r e a s e o f t h e a c i d

n e u t r a l i z i n g capacity,

g i v e s us a t o o l t o compare r a t e s o f a c i d i f i c a t i o n i n

v a r i o u s s o i l t y p e s i n v a r i o u s s t a g e s o f n a t u r a l and a n t h r o p o g e n i c acidification.

I n o r d e r t o e v a l u a t e e c o l o g i c a l c o n s e q u e n c e s o f changes i n

s o i l c h e m i s t r y due t o atmospheric d e p o s i t i o n ,

pH a n d c o n c e n t r a t i o n s o f

aluminum as compared t o base c a t i o n s need t o be assessed.

For understanding

t h e c h a n g e s o f t h e s e s o i l c h e m i c a l p r o p e r t i e s c a t i o n e x c h a n g e and m i n e r a l w e a t h e r i n g a r e k e y processes.

C r i t i c a l p a r a m e t e r s a r e c a t i o n exchange

c a p a c i t y , b a s e s a t u r a t i o n , and t h e r a t e and t h e s t o i c h i o m e t r y o f m i n e r a l d i s s o l u t i o n r e a c t i o n s . S o i l s w i t h a l o w CEC and l o w base s a t u r a t i o n and l o w base w e a t h e r i n g r a t e s a r e most s u s c e p t f b l e t o a d v e r s e e f f e c t s o f a c i d i c d e p o s i t i o n . S o i l s w i t h a h i g h CEC a n d h i g h a m o u n t o f e x c h a n g e a b l e

w i l l be most d i f f i c u l t t o a m e l i o r a t e by l i m i n g .

H and A1

If, additionally,

the

d i s s o l u t i o n r a t e s o f base c a t i o n s f r o m s i l i c a t e m i n e r a l s a r e low, n a t u r a l recovery o f t h e s o i l a f t e r deposition r a t e s a r e lowered Experimental

w i l l be v e r y slow.

studies t o obtain c r i t i c a l parameters i n combination w i t h t h e

use o f s i m u l a t i o n models w i l l be i m p o r t a n t t o p r e d i c t f u t u r e changes i n s o i l c h e m i s t r y f o r d i f f e r e n t e m i s s i o n / d e p o s i t i o n s c e n a r i o s and t o p r e e v a l u a t e m i t i g a t i o n strategies f o r forest soils.

RE1-ERENCES

1 N. van Breemen, J. M u l d e r and C.T. 2 3 4 5

6

Driscoll.

P l a n t and S o i l 75 (1983) 283-

T. Schneider (Editor)/Acidification and its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

EFFECTS OF ACIDIFICATION ON MATERIALS AND CULTURAL PROPERTY N.S. BAER Conservation Centerr New York University, 14 East 78th Street New Yorkr New York (U.S.A.) ABSTRACT Historic structures1 outdoor sculpturer museum and library artifacts, and the common materials of construction are all affected by acid deposition. The naturer magnitude and extent of observed damage to materials is discussed. Dose-response relationships or damage functions are reviewed with reference to their ability to predict the benefits of environmental reductions in acid deposition. The multistep process whereby dollar costs are assigned to damage associated with a given cause (e.g. SO28 acid precipitationr particulate soiling) is outlined in the form of a flow diagram. In the discussionr the status of knowledger unknownst uncertainties and research needs are noted. INTRODUCTION Even the casual observer is confronted daily by the combined effects of air pollution and natural weathering induced materials damage. The bridgest roadst buildingst and utilities that form our urban infrastructure are joined with our cultural monuments and artifacts in vast materials maintenance and replacement projects. A U.S. Department of Commerce Report (ref. 1) estimates the total annual metallic corrosion cost in the U.S. at $82 billion in 1975. Far greater sums will be required for the repair and replacement of damaged reinforced concrete facilities and structures. A sense of the scope of such projects is provided by the estimated time and cost for repairs to the four major East River bridges in New Yorkt an average of 13 years and $180r000~000per bridge (Table 1). Repair and refurbishment costs for cultural properties, e.g. $ 4 0 ~ 0 0 0 ~ 0 0each 0 for the Statue of Liberty and U.S. Capitolr present proportionately large public expenditures. Less

17

78

visible and more difficult to quantify are the maintenance and replacement costs expended by private owners of small business and residential properties. TABLE 1. Estimated Cost of Repairs to Major Bridges in New York City.a

Brooklyn Manhattan Queensboro Williamsburg

15

10 12 15

138 r300 r O O O 135r900r000 202 r 2 0 0 r O O O

231r700r000 708r100,OOO (total)

a Data supplied by the New York State Transportation Department. Projects began 1980-1981 fiscal year. Anticipated completion 1994-1995 fiscal year. Estimates subject to change.

In the press and popular literaturer damage to materialsr in particular cultural propertiesr is with increasing frequency assigned to "acid rain" or acid precipitation. A key issue thus becomes1 what is known about the effects of acid deposition on materialsr what roles do other pollutants playr and what levels of damage would be observed due to natural weathering phenomena in the absence of anthropogenic pollutants. Phrased in the terminology of the policy-makerr what can be stated with confidence about the decrease in the rate of damage to materials that will result from an incremental reduction in emissions. MATERIALS EFFECTS In Table 2 r the natural weathering phenomenar effects of other pollutants and effects of acid deposition are tabulated together with methods for quantifying damage and possible

Tabla 2. A i r P o l l u t i o n Damage t o M a t e r i a lb

Type o f

Other -

Principal A i r Pollutants

Oamaae

Methods of Maasu rement

M i t i q e t ion Measures

Weight Loss o f sample, surf a ce reflectivity, measurement o f dimensional changes, chemical a n a l y s i s

C leaning, im preg nati on w i t h re s ins , removal t o c o n t r o l l e d environment

Moisture

Loss i n surf a ce r e f l e c t i v i t y and l i g h t trans mi s sio n . change i n th ick n ess , chemica 1 ana l y s i s

P r o t e c t i v e c oati ngs, replacement w i t h more r e s i s t a n t m a t e r i a l , removal t o c o n t r o l l e d e n v i ronment

Moisture, e i r , sa L t , pa r t i c u Late matter, ozone

Weight Loss a f t e r removal o f corr o s i o n products, chenge i n su r fac e characteristics

Surface p l a t i n g or coati ng, replacement w i t h co rros ionr e s i s t a n t m a t e r i a l , removal t o c o n t r o l l e d environment

Su 1fu r oxides hydrogen eu L f i d e , a l k a l i n e aerosol

Moisture, s u n l i g h t , ozone, p a r t i c u l a t e matter, microorganisms

S urface r e f L ect i v i t y loss, chemical ana l y s i s

Repa i nti n g, rep Lacament w i t h a more r e s i s t a n t material

Ozone

Sunlight. physical wear

Loss i n e l a s t i c i t y end strength , maasurement o f c r ack frequency and depth

Add a n t i o x i d a n t s t o f o r n r ulation, r epla ce w i t h more r e s i s t a n t m a t e r i e l s

Bui Lding Stone

Surface erosion, S u l f u r oxides s o i l i n g , black end o t h e r a c i d c r u s t f o r m a t i o n gases

Ceramic and Glass

Surface erosion, A c i d gases, surface c r u s t espacia 1Ly formation f Luoridecontaining

Meta 1s

Corrosion, t a r n i s h i ng

Paint end Organic Coatings

Discoloration soiling, erosion

Rubber

C racking

a

Su L f u r oxides, and o t h e r a c i d gases, hydrogen su L f i d e

,

,

Envi ronmental Factors Mechanical erosion, p a r t i c u l a t e matter, moisture, temperature fluctuations, salts, v i b r a t i o n , Cog, microorganisms

Adeptad from Reference 12). F o r Leather, Magnetic Storage Media, Paper, Photographic M a t e r i a l s , T e x t i l e s and T e x t i l e Oyes sea Table 1 o f "Effects o f A c i d i f i c a t i o n i n A rchives and Museums," T h i s volume. U

0

80

mitiga.tive strategies. With rare exceptionsr damage is the result of ntultiple fact.ors interactingr at times! in a synergistic manner.

Dama.ge may be measured by weight lossr loss of strength, soiling, erosion, chemical analysis, etc. Most frequently damage has been measured by weight loss. This reflects the usual experimental method where a weighed test specimen is exposed to the environment or in a test chamber for a given period. At the end of the exposure the corrosion layerr if anyr is stripped o f f and the test specimen is weighed. The loss of mass is defined as the da-mage. Various assumptions are made to convert the weight loss to dimensional surface erosion. In many casest e.g. aluminum (pitting) paint (delamination)I sandstone (spalling), the mode of failure is not by uniform surface loss so that this conversion is inappropriate.

In generalr three approaches are taken for the quantification of damage to materials: 1. Field exposure of prepared specimens, 2. Chamber studies in controlled environmentsf and 3 . Retrospective studies of exposed materials. Field exposure studies which approximate normal conditions are slow and seldom continue for realistic time periods. How relevant is a 2-year exposure study of freshly quarried polished marble to the Parthenon? Furtherr how well can we characterize the variations in atmospheric conditions, and indeedr the causative agents interacting with our specimen when we only intermittently examine that sample. Similarlyr when evaluating the results of chamber studiesr how well have we simulated the real world. In our synthetic atmospheret have we omitted a critical ingredient# p ~ g , ozone or carbonyl sulfide o r an aspect of natural weatheringt ng, UV radiation or f reeze-thaw cycles. While retrospective studies are clearly of great relevance,

81

they often present frustrating results. The evidence of damage is realr compellingr and readily characterized. What is lacking is any reliable data on the conditions to which the artifact was exposed.

The role of the damage function is to describe the relationship between natural loss, soiling, etc. and such environmental variables as S 0 z r NO,, Cl-, precipitation pH1 time- of-wetness, dustfallr and insolation. The damage function may be: entirely theoretical: based on curve-fitting using regression analysis of field or laboratory data; or a combinationr fitting a body of experimental data to a model of corrosion. A great many damage functions have been generated for metal systems while relatively few are available for other materials. The most successful is that for zinc as affected by S02. The literature reporting damage functions has been reviewed generally by various authors (ref. 2-61 and specifically for metals by Benarie (ref. 7 ) and carbonate paints by Livingston (ref. 8). vs. C

o

K

r

o

S

m

When damage functions are developed from weight loss experimentsr little insight is gained into the mechanism of damage. Yetr it is the determination of damage reaction mechanisms that is essential to the development of mitigative strategies and the assignmentr with confidence1 of the portions of damage attributable to wet and dry depositionr other anthropogenic factorst and natural weathering. The reaction mechanism provides a detailed and complete sequence of reactions from the initial phases of attack through conversion to corrosion products. Some indication of the complexity of corrosion mechanisms is gained in Table 3 where the results of anion analyses for corrosion products on metals exposed both indoors and outdoors are compiled (ref. 9). In the case of copper: OH-, SO4'r S=I CO35 NO3- and C1- have been observed both indoors and outdoors. Similarlyr zinc exposed outdoors has OH-I sO4=1 cO3=1 and C1in its patinas while on exposure indoors only SOq', NO3- and

C1- were reported. Yet most damage functions for zinc only consider SO2 and some time-of-wetness related variable. TABLE 3. Anions Found in Corrosion Films on Metalsa Metal

Location

Ag A1 Cd co cu cu Fe Ni

Indoor Indoor Indoor Indoor Indoor Outdoor Indoor Indoor Outdoor Indoor Outdoor Indoor Outdoor

Pb

Pd Sn Zn Zn

a b

OH-

SO4'

*b

-

-

* *

*

* *

-

*

* * * *

* * * *

-

S'

*

CO3'

N03-

C1-

*

* *

* * * * *

-

-

-

*

*

* *

-

*

* *

*

*

* * * *

* *

*

*

* * * * *

After Franey and Graedel (ref. 9). * denotes anion reported.

ECONOMIC CALCULATIONS The goal of these studies is to identify the causes of damage, assist in the development of mitigative strategies, and ultimately to develop an economic evalution of damage. The process illustrated in Figure 1 involves many inputs in addition to dose-response damage data. The approach shown is that used in the 1985 draft EPA Assessment, generally available but never officially relased (ref. 10). It is essential to realize that each of the inputs is subject to error and bias. For examplet there is no credible damage function currently available for any single stone type. Thust the $5 billion annual acid deposition damage loss for 17 Northeastern States as reported in the (ref. 11) and based on the draft report may well be revised downward by an order of magnitude as the data and assumptions used undergo careful

83

Invantory Accounting

Sampled T r a c t Inventory

Unsampled T r a c t Inventory

Po 1l u t a n t s , Natural

Damage F u n c t i o n Dose Response

A i r b et it y Data

P a i n t e d Surfaces Galvanized S t e e l Bui l d i n g Stone Mortar Cu 1t u r a 1 P r o w r t i e s L o c a l 5% Regional S%

-

T i me-of-We tness Hetaoro logy

I

Damage Rates

-Service L i f a t ime

1

C r i t i c a l Damage Level

*

-

Product Speci f i c e t i on

Change i n Maintenance Interve1

i

Mode 1 Inputs

Computation o f D o l l a r Damages

Aggregation

-

Meintanancd Replacement/ Repai r/Costs

-

T o t a l Costs by M a t e r i a l s and Bui l d i n g Type

I

T o t a l Costs f o r M a t r o p o l it a n S t a t l e t i c e 1 Areas

Flg. 1.

by B u i l d i n g Type b y P o l l u t a n t Sourca by N a t u r a l Weethering

FLOWDiagram f o r M a t e r i a l s E f f e c t s Estimates. A f t e r F i g u r e 3.5-27 H e t a r l a l s E f f e c t s Chapter f o r t h e 1885 Assessment [ raf. 101.

!PA D r a f t

84

analysis. It is of interest to note that the overwhelming percentage of damage was assigned to painted surfaces.

The consumer, be it individual home ownerr corporate officerf or custodian of cultural propertyt is assumed to behave in a rational manner when confronted with materials damage. In the case of common building materials the market is considered to reflect behavior. Mitigation strategies for common building materials were listed in Table 2 . Specific examples of replacement or substitution for materials where air pollution may be thought to be a cause of damage are given in Table 4 . It is important to note that such replacements may introduce increased value (reduced future replacement intervals or costs; improved appearance; reduced maintenance) or may represent a loss of value (loss of options in surface treatmentsr increased risk of other types of damaget e.g.1 lightr fire hazard). Economic models generally incorporate such concepts. TABLE 4. Illustrative Replacements or Substitutions for Pollution Impacted Materials. Subc+iLuie M Galvanized link fence Carbonate filled paint Marble grave marker Wood ( painted/unpain ted) Coated carbon steel Copper gutters and leaders Copper flashing

a

w

Vinyl coated link fence Silicate filled paint Granite grave marker Aluminum siding (coated) Weathering steel Aluminum gutters and leaders ( coated 1 Stainless steel flashing

CULTURAL PROPERTY It is the case that in the United States materials damage and in particular damage to cultural property is considered f a r less important than effects on agriculture# soilr water?

forests and human health. This contrasts with the from the -vnE on Acid Rain (ref. 12) where the lead area of interest was damage to buildings. The reason f o r this is clear if we contrast the situation with regard to stone monuments in the U.S. and Canada with that in Europe (Table 5 ) . Howeverl damage to cultural property cannot be evaluated in simplistic terms. The public will support substantial expenditures for the preservation of important monumentsl our Declaration of Independence1 sealed in heliuml displayed under reduced illumination and lowered into a vault each evening or the great public support for the restoration of the Statue of Liberty and Ellis Island. An indication of estimated costs associated with air pollution damage to cultural monuments is given in Table 6. Further, just as a small level of material loss may lead to catastrophic failure of an electrical switchl a bridge, or an architectural element1 damage to cultural property is irreversible and not readily subject to economic evaluation. What is lost is lost.

TABLE 5. C o n t r a s t i n O i s t r i b u t i o n , C h a r a c t e r i s t i c s , and A i r P o l l u t i o n E f f e c t s on Stone and Canada Monuments i n Europe va. t h e U.S.

Europe

Cha r a c t a r i a t ic

U.S.

Quantity

Few

Many

Age

Usually lass then 100 years

Continous from p r e h i s t o r i c t o present

O i s t r ib u t ion

G e n e r a l l y urban w i t h exception of American I n d i a n sites

Widely d i s t r i b u t e d

Stone t y p e s

Generally durable except f o r sandstones

Often poor q u a l i t y s t o n e chosen f o r ease o f c u t t i n g and c a r v i n g

Oegrea o f Working o f Stone

L i m i t e d examples, some free-standing sculpture

S t a t u a r y , scu l p t u r e , decorative carving commonly i n c o r p o r a t e d as a r c h i t e c t u r a l e laments

Po 1l u t i o n Levels

W i t h soma exceptions r e l a t i v e l y Low, m a t e r i a l s impact u s u a l l y deminated b y l o c a l sources

R e l a t i v e l y high, e s p e c i a l l y i n urban and i n d u s t r i a l areas

and Canada

TABLE 6 Estimated R e s t o r a t i o n Costs Associated w i t h A i r P o l l u t i o n Damage t o C u l t u r a l Property.a Countrl or City Germany [FRGI

Tvpe o f Cu l t u r a 1 PropertK Medieval Stained Glass

Bas i 6

f o r Cost Estimate Oarnags

Period

for

Estimate Total

cost -

Year -

200-300

Estimate 1980

[ m i Llions]

of -

[DM1

London

Houses o f Par Liament

Repair o f Fabric

Tota 1

5

1980

Rome

Monuments

Repel r of Damage

10 year Expendi t u r n

200b I$US]

19BO

Netherlands

Monuments

Conservation

Total

120-200 [Dutch Gui Lderl

1984

New York

Statue o f Liberty

Conservation/ Refu r b i ehment

TotaC

40b [ SUSl

1986

a

(L1

Adapted i n p a r t f r om r e f . 2. C o d i n a d c o s t s of r e p a i r i n g n a t u r a l weathering and a i r p o l l u t i o n induced damage.

87

REFERENCES 1.

L.H. Bennett1 J. Krugerr E. Passagliar C. Reimannr A.W. Ruff, and E. Yackowitzf Economic Effects of Metallic Corrosion in the United Statesr Part I: A Report to the Congress by the National Bureau of Standards. NBS Special Publication 511-1, U.S. Department of Commercer National Bureau of Standardsr Washington, D.C.r 1978. 2 J.E. Yocom and N.S. Baerr in The Acidic Deposition Phenomenon and its Effects: Critical Assessment Review Papersr U.S. EPAI Washington, D.C. EPA-600/8-83-016BFt 1 9 8 4 ~chapter E-7r section 7.1. J.E. Yocomr N.S. Baer and E. Robinson, in A.C. Stern (Ed.), Air Pollution, Volume VIf Academic Press, New Yorkr 19861 chapter 4. J.E. Yocom and A.R. Stankunasr A Review of Air Pollutant Damage to Materialsr A Report to the EPA Environmental Criteria and Assessment Officer 1980. S.E. Haaqenrudr R.W. Lanting and G. Santomauror "Draft Report on Effects of Sulphur Compounds on Materialsr Including Historical and Cultural Monumentsr UNESCO1 Interim Executive Body for Convention on Long-Range Transboundary Air Pollutionr Geneva1 Switzerlandr 1982. 6 P. Harterr Acidic Deposition and Damage to Materials and Human Health1 Working Paper 711 IEA Coal Researchr London1 1986. 7 M. Benarier Metallic Corrosion as Functions of Atmospheric Pollutant Concentrations and Rain pHf BNL 35668r Brookhaven National Laboratory1 Upton, New Yorkr 1984. 8 R.A. Livingstonr Pap. Froc. Annual bieeting, Air Pollution Control A S S O C . ~ 86, 85.71 1986. 9 J.P. Franey and T.E. Craedel, JAPCAr 35, 1985r 644-648. 10 Environmental Protection Aqencyr Draft Materials Effects Chapter for the 1985 Assessment. 11 P. Shabecoffr The New York Timesf 18 July 1985. 12 Fourth Report from the Environment Committee Session 1903-19841 Acid Rainr Volume 1, Paragraph 37r p. xxiir H.M. Stationary Officer London, 1984.

89

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands ECOLOGICAL Yu.A.

HORIZON

I z r a e l , S.M.

Semenov

N a t u r a l Environment and C l i m a t e M o n i t o r i n g .Laboratory, USSR S t a t e Committee f o r Hydrometeorology and C o n t r o l o f N a t u r a l

Environment / USSR Academy o f Sciences INTRODUCTION Environmental ecological

pollution

changes

is c o n s i d e r e d t o

nowadays

bring

about

o f s i g n i f i c a n t l y l a r g e s c a l e s . E a r l i e r , l o c a l problems

r e l a t e d t o e n v i r o n m e n t a l p o l l u t i o n i n t h e v i c i n i t y o f c i t i e s and i n d u s t r i a l enterprises

were

significantly

in

the

changed:

focus

o f i n v e s t i g a t i o n s . Now t h e s i t u a t i o n has

environmentalists,

along

with

wide

public

and

governmental agencies d i s c u s s r e g i o n a l s c a l e problems such as t h e e f f e c t o f long-range p o l l u t i o n t r a n s p o r t on f r e s h - w a t e r ecosystems i n Scandinavia, o r t h e s t a t e o f f o r e s t s i n t h e European Region. Some o f t h e a r i s e n answers

are

fairly

questions

clear,

e.g.

have the

d e g r a d a t i o n o f f r e s h - w a t e r bodies i n diagnostics

of

already

been

analysed

and

negative

role

of

rains i n

In

other

Scandinavia.

t h e causes o f f o r e s t s weakening i n

Europe i s n o t i n a p o s i t i o n t o i n d i c a t e t h e m a j o r ecology

acid

the

cases,

e.g.

C e n t r a l and Western factor.

Modern

applied

does n o t possess adequate methods as y e t , i t can p r o v i d e o n l y some

c o n c l u s i o n s o f general q u a l i t a t i v e n a t u r e [ll]. However, t h e i n t e n s i t y and s c a l e o f t h e observed phenomenon, s t a t e d a t the

meeting

o f t h e r e p r e s e n t a t i v e s o f 30 c o u n t r i e s i n Munich i n j u n e 1984

and t h e T h i r d Session o f t h e E x e c u t i v e Body f o r range

Transboundary

Air

Pollution

f o r m u l a t e and s t a r t i m p l e m e n t a t i o n o f

in

July

requisite

the

Convention

on

Long-

1985, s t i p u l a t e t h e need t o

ecological

research,

to

u n d e r t a k e p r a c t i c a l measures i n t h i s sphere. I n t h e n e a r e s t f u t u r e i t i s necessary t o develop a r e l i a b l e to

assess

t h e e f f e c t o f an aggregate o f a n t h r o p o g e n i c g l o b a l and r e g i o n a l

f a c t o r s , environment a c i d i f i c a t i o n i n c l u d e d , on t h e ecosystems.

technique

It

state

of

continental

is necessary t o s e p a r a t e t h e e f f e c t o f each f a c t o r f r o m t h e

90

i n t e g r a l e f f e c t , t o r e l i a b l y d i s t i n g u i s h man-induced background

of

natural

changes

against

v a r i a t i o n s i n t h e s t a t e ecosystems.

t h e s e problems, one m i g h t make s u b s t a n t i a t e d recommendations i n t h e of

monitoring

the

effects,

pollution

the

Having s o l v e d

standardization,

and

sphere rational

l i m i t a t i o n o f p o l l u t a n t discharge. These are, i n o u r research

in

the

opinion,

outlines

of

perspective

directions

of

sphere o f a p p l i e d e c o l o g y today. Below, we a r e t r y i n g t o

d e s c r i b e more s p e c i f i c a l l y t h e essence o f t h e s e d i r e c t i o n s and t h e i r goals, p r o b a b l e m e t h o d o l o g i c a l

approaches,

outcomes

t o certain

major practical

questions o f ecological standardization. OXIDES OF SULPHUR AND NITROGEN

environment

Hundreds and thousands o f p o l l u t a n t s a r e e m i t t e d i n t o t h e due

to

anthropogenic a c t i v i t i e s .

However, o n l y few o f them a r e c a p a b l e o f

c o n t i n u o u s l y a f f e c t i n g ecosystems on a c o n s i d e r a b l e s p a t i a l order

of

km,

depending

toxicity, ability t o

1,000

propogate,

nitrogen, priority

being

constituents

pollutants

vegetation.

It

to

should

be be

on

the

and of

they

effect

emission forth.

atmospheric

studied

with

stressed t h a t

p r i m a r y f a c t o r s , s i n c e s p r e a d i n g and environments

so

amounts, Oxides

of

scale

the

persistence,

of

sulphur

and

p o l l u t i o n , are t h e primary

respect

to

their

effect

on

these p o l l u t a n t s a r e t h e major

circulating

in

natural

geophysical

p l a n t s b o t h d i r e c t l y and i n d i r e c t l y by i n d u c i n g

secondary ( d e r i v a t i v e ) adverse f a c t o r s , which a r e d i s c u s s e d below. The d i r e c t impact o f s u l p h u r and penetration

nitrogen

oxides

is

due

s t r o n g a s s i m i l a t i o n poison. An approximate l i s t o f v a r i o u s SO c o n c e n t r a t i o n e f f e c t s on h i g h e r p l a n t s i s g i v e n i n [13]. Changes

to

their

i n t o green a s s i m i l a t i v e organs o f p l a n t s . Sulphur d i o x i d e i s a

induced

by

< 30

o f mathematical models. SO and yg/m

3

rate

of

c o n c e n t r a t i o n s f r o m 30 yg/m

yg/m

atmospheric

3

are beyond 2 i n s t r u m e n t a l d e t e c t i o n , though t h e y a r e l i a b l e t o be assessed w i t h t h e h e l p SO

concentration

2

3

reduce t h e c o n t e n t 2 g a l a c t o l i p i d e s y n t h e s i s i n p h o t o t s y n t h e s i s i n g c e l l s ; 250-280

b r i n g about u l t r a s t r u c t u r a l changes

e l e c t r o n microscopy ; 500-1000 y g/m content, i n a c t i v a t e

3

chlorophyllase,

in

chloroplasts

registered

by

reduce oxygen emanati on and c h l o r o p h y l 1 desorganize

tilacoids

and

membrane

91

systems; 1000-1400 Ug/m

3

cause c o n t i n u o u s d e g r a d a t i o n o f o r g a n e l l e s , a f f e c t

p r o t e i n and l i p i d e s y n t h e s i s , c o n s i d e r a b l y reduce GO increase

in

SO

n e c r o s i s , death.

concentration

2

These changes a r e accompanied by proportions,

a f f e c t e d processes

assimilation. Further 2 causes a c u t e damage t o p l a n t s : c h l o r o s i s ,

changes of

in

morphology:

affected

such e c o l o g i c a l l y and e c o n o m i c a l l y i m p o r t a n t c h a r a c t e r i s t i c s o f of

vegetation

as

woodstand

plant

p r o d u c t i o n . The l a t t e r d i r e c t l y e f f e c t

growth

and

agrocenoses

the

yields.

state

The most

s e n s i t i v e t r e e s p e c i e s a r e p i n e and spruce. Evidently, the Concentrations

up

SO s e n s i t i v e p l a n t s are e p i p h y t i c lichens. 2 3 100 yg/m do n o t cause d e a t h o f h i g h c r p l a n t species

most to

b u t k i l l many e p i p h y t i c l i c h e n s . lichens of

as

are low

The most

sensitive

genera Usnea, L a b a r i a , S t i c t a a

photosynthesis

concentration [6].

The

as

30 yg/m

3

groups

of

epiphytic

Ramalina, Cladonia; t h e e f f e c t reduces

intensity

of

their

r e v i e w o f t h e e f f e c t o f s u l p h u r d i o x i d e and of a

number o f o t h e r p o l l u t a n t s i n l i c h e n s can be found i n [3,4]. It s h o u l d be n o t e d t h a t t h e amount o f r e l i a b l e

t h e e f f e c t s o f SO

e x p e r i m e n t a l d a t a on 3 c o n c e n t r a t i o n s w i t h i n t h e range o f 0-100 Ug/m i s r a t h e r

2 i n s u f f i c i e n t . The d a t a o f f i e l d o b s e r v a t i o n s show c o n s i d e r a b l e n o i s e due t o

the

effect

of

other

factors

and

b i o l o g i c a l o b j e c t s . Though, i t i s t h i s characteristic

of

the

of

n a t u r a l time-space v a r i a b i l i t y o f range

of

concentrations

that

is

European

r e g i o n as a whole. W i t h i n Western Europe 3 3 areas w i t h c h a r a c t e r i s t i c average c o n c e n t r a t i o n s 10 yg/m , 10-25 yg/m and 3 25 yg/m make up 69%, 30% and 1%, r e s p e c t i v e l y , as e s t i m a t e d i n [2]. The s i t u a t i o n may have changed now, though i n s i g n i f i c a n t l y . The e f f e c t s o f n i t r o g e n o x i d e s on p l a n t s i s supposed t o m a n i f e s t i n s i m i l a r way, t h o u g h r e l e v a n t s t u d i e s

are lacking

. The development

s t u d i e s i s u r g e n t . Another reason t o comprehensively s t u d y emissions

and

distribution

is

stipulated

occurence

nitrogen

oxide

by t h e i r i n d i r e c t s e f f e c t s on

p l a n t s , t h e t r u e s c a l e s o f which a r e y e t h a r d l y assessed. the

a

of such

What we i m p l y , i s

o f a n t h r o p o g e n i c ozone. F a i r l y complete i n f o r m a t i o n on t h i s

problem, d i s c u s s e d b r i e f l y below, i s g i v e n i n [71. Ozone i s known t o f o r m i n t h e atmoshere i n t h e c o u r s e o f photochemical and t h e r m a l r e a c t i o n s : NO

2

+ h y --> NO + 0:

92

+

+ M' --> 0 + M' 2 3 M' i s a m o l e c u l e a b s o r b i n g t h e 0:

0

reactions degree,

is

reaction

energy.

The

kinetics

of

these

complex and depends on l i g h t spectrum c o m p o s i t i o n , r a d i a t i o n

presence

of

metals,

hydrocarbons,

and

particulates

in

the

atmosphere. Thus,

man-made

anthropogenic

emission ozone.

of

The

nitrogen

oxides

induces

atmospheric

content

of

c o n t i n e n t a l areas i s t h o u g h t t o b e 0.01-0.02 Western

Europe

-

t h e i r surroundings) Ozone imposes

0.02-0.04

-

0

3

ppm; r e g i o n a l

formation over

of

background

background

for

ppm; c h a r a c t e r i s t i c i m p a c t l e v e l s ( c i t i e s and

0.1 ppm.

h i g h p h y t o t o x i c effects.

Ozone i s

believed

to

bring

90% o f t h e t o t a l c r o p l o s s i n t h e USA o u t o f t h e i m p a c t o f t h e whole

about

o f a l l a t m o s p h e r i c p o l l u t a n t s . I n d e n t i f i c a t i o n o f t h e p r e c i s e mechanism ozone

phytotoxic cffects

i s s t i l l ambiguous.

r a d i c a l s , formed as a r e s u l t o f i t s organs

of

Ozone a l s o supposed,

of

I n p a r t i c u l a r , ozone and i t s

penetration

into

green

assimilative

plants,

a f f e c t p o l y u n s a t u r a t e d f a t t y a c i d s and t h i o l i c groups.

affects

photosynthesis

penetrating

processes

in

chloroplasts

when,

as

i n t o c h l o r o p l a s t s and/or i n d u c i n g r a d i c a l f o r m a t i o n

i n them. T r i a l d a t a ( s e e Table 1) show s i g n i f i c a n t damage f r o m r e g i o n a l o f ozone, c h a r a c t e r i s t i c o f Western Europe.

levels

93

Table 1 0

3

E f f e c t s on p l a n t p r o d u c t i v i t y ( f r o m [7],

~~~~

Species

~

0

3

~~

concen-

~

adapted)

~~~

Dose

tration

Effect ,

Measured

control

parameter

percentage Trifolium

0.03

8 h r x 6 weeks

92.3

f r e s h p l a n t mass

0.05

6 h r x 74 days

93.8

number o f g r a i n s

0.05

8 h r x 5 times

68.9

f r e s h p l a n t mass

incarnatum Zea mays Go1 den Midget variety Rhaphanus sativus Cherry B e l l variety

a week x 5 weeks G l y c i n e max Dare v a r i e t y

0.05

6 h r x 43 days

75.4

t h e same

0.05

6 h r x 28 days

86

t h e same

0.05

t h e same

86

t h e same

P i nus taeda Wild f o x t a i l pine Fraxinus pencyl vani ca Black ash

94

The e f f e c t o f o v e r 0.1 ppm may be as biomass

decrease,

this

n o t e d t h a t common d i a g n o s t i c s (morphological )

great

as

50% o f

the

demonstrates h i g h t o x i c i t y o f ozone.

features

[8] of

begins

plant to

damage

show

control

It s h o u l d be

by v i s u a l 3 r e s u l t s when

0

with

significant

c o n c e n t r a t i o n s a r e c l o s e t o 0.1 ppm. be1 i e v e

We

information

that

available

one, a f t e r p r o p e r p r o c e s s i n g , t o models

a

world

ecotoxicological

"dose-effect''

w i t h r e g a r d t o ozone e f f e c t on t e r r e s t r i a l p l a n t s would e n a b l e prediction

of

the

assess

with

the

help

of

mathematical

e f f e c t o f ozone on v e g e t a t i o n i n Europe. It

would r e q u i r e g e o p h y s i c a l assessment o f t h e f i e l d

of

anthropogenic

ozone

over Europe, and a p r e d i c t i o n o f i t s changes as a f u n c t i o n o f a n t h r o p o g e n i c f a c t o r s , i n p a r t i c u l a r , n i t r o g e n o x i d e emissions. The presence o f a number o f c o n s t i t u e n t s i n t h e layer,

sulphur

and

nitrogen

atmosperic s u b - c l o ~ ~ d

o x i d e s and s u l p h a t e s i n c l u d e d , r e s u l t s i n a

certain natural acidity o f precipitation

(pH

5.6).

The

growth

of

the

c o n c e n t r a t i o n o f t h e s e c o n s t i t u e n t s due t o human a c t i v i t i e s , i n d u s t r i a l and t r a n s p o r t emissions, i n c r e a s e s p r e c i p i t a t i o n a c i d i f i c a t i o n , i n up

t o pH

4.5.

some

cases

Thus formed a c i d r a i n s p r e s e n t a v e r y s i g n i f i c a n t f a c t o r o f

man-induced e f f e c t on t e r r e s t r i a l ecosystems [6]. On a l o c a l s c a l e near c i t i e s and i n d u s t r i a l e n t e r p r i s e s a c i d r a i n s can show

up

direct

effects,

in

particular,

a c u t e p l a n t damage, w h i l e on a

r e g i o n a l s c a l e i t i s more d i f f i c u l t t o r e v e a l t h e e f f e c t o f a c i d

rains

on

v e g e t a t i o n [14]. An experiment w i t h i n Norway, P r o j e c t SNSF, was performed t o d e t e c t t h e e f f e c t o f a c i d i f i c a t i o n on t h e growth o f c o n i f e r o u s t r e e s ( p i n e and s p r u c e ) under non-impact c o n d i t i o n s u s i n g f i e l d methods. S t a t i s t i c a n a l y s i s o f annual

rings

r e v e a l any

the

o f Norway spruce and Scotch p i n e a t 6150 t r i a l s i t e s d i d n o t

association

with

soil

acidification.

The

model

estimated

decrease i n g r o w t h made up 0.5%, w h i l e t h e experiment r e s o l u t i o n s t i p u l a t e d by t h e d i s g u i s e e f f e c t o f o t h e r f a c t o r s , happened

to

be

over

1% [12].

It

p r e c i p i t a t i o n can s t i m u l a t e growth on

anthropogenic should

alkaline

also soils

be

factors noted with

included, that

nitrogen

acid and

95

s u l p h u r d e f i c i e n c y [6]. G e t t i n g o n t o s o i l , a c i d r a i n s w i t h pH c 5.6 e f f e c t c a t i o n exchange 2 2 + + + + , MG , K , Na a r e r e p l a c e d w i t h H T h e i r f l u s h (wash down)

.

processes: Ca

t o under-ground water sulphates

and

d e p l e t e s s o i l . On t h e o t h e r

nitrates

with

acid

precipitation

growth, b u t t h e n induces d e f i c i e n c i e s compostions.

Soil

acidification

hand,

of

K,

of

f i r s t stimulates plant

P

Mo,

introduction

which

changes

soil

r e s u l t s i n t h e o c c u r r e n c e o f t o x i c heavy

m e t a l s i n t h e s o i l s o l u t i o n . Aluminium, t r a n s f o r m i n g i n a c i d i f i e d s o i l s (pH into

5.0)

soluble

form,

stimulates

washout

o f calcium, organic matter

s e d i m e n t a t i o n , bounding o f p l a n t a c c e s s i b l e phosphorus,

adversely

growth o f r o o t c e l l s and p l a n t s t a t e of t h e whole.

the

discussed i n d e t a i l i n

effects

These processes a r e

[lo].

Because o f t h e v a r i e t y o f t h e e f f e c t s o f a c i d r a i n s g e t t i n g o n t o s o i l s and

ambiguity

of

t h e i n t e g r a l e f f e c t , model l a b o r a t o r y experiments under

c o n t r o l l e d c o n d i t i o n s have been performed. The scheme o f a s p e c i a l e x p e r i m e n t which

is

-

" s o i l algae-test",

t h e essence o f

i n soil extraction with a solution o f certain acidity (acid rain

s i m u l a t i o n ) , f u r t h e r growth o f u n i c e l l u l a r f r e s h - w a t e r a l g a e i n t h e e x t r a c t and r e g i s t r a t i o n o f t h e i r r a t e o f i n c r e a s e i s d e s c r i b e d i n [9]. U n i c e l l u l a r a l g a e have been t a k e n i n s t e a d o f h i g h e r p l a n t s because

of

the

desire

to

t h e experiment f a s t e r and expediency o f measuring t h e c u l t u r e d e n s i t y

make

u s i n g a u t o m a t i c f a c i l i t i e s . The specimen o t t y p i c a l soil-podzol

soil,

exemplified

in

the

for

the

acidic

USSR

c i t e d paper, i s c h a r a c t e r i s t i c o f

a l m o s t h a l f o f t h e USSR t e r r i t o r y . B a c t e r i a - f r e e u n i a l g a l c u l t u r e o f C h l o r e l l a COIO, o f f e r e d by t h e P l a n t Physiology

Institute

of

the

USSR Academy o f Sciences, was t e s t e d i n t h e

experiment. S o i l e x t r a c t i o n was performed by d i s t i l l e d water a c i d a t e d sulfuric

a c i d . The a p p l i e d s o l u t i o n s were: a c i d s o l u t i o n (pH = 2.0 % 4.5),

s u b a c i d (pH = 5.0 % 6.0), 30

or

60

minutes.

and n e u t r a l (pH = 6.5).

Statistical

revealed e f f e c t

-

Extraction duration

-

15,

a n a l y s i s o f t h e r e s u l t s has r e v e a l e d t h e

e f f e c t on a h i g h l e v e l o f r e l i a b i l i t y the

with

-

up t o 95% and

higher.

Note,

change i n t h e r a t e o f t h e t e s t c u l t u r e growth

-

that i s an

96

i n t e g r a t e d effect, properties

t h e response t o a l l t h e

occurring

with

the

changes

change

in

the

in

the

soil

extractor

extract

acidity

and

e x t r a c t i o n duration. It s h o u l d be s t r e s s e d a g a i n t h a t emanation o f heavy m e t a l s , o f

particular,

induced

by

A1

in

soil acidification i s o f certain significance f o r

t h e o c c u r i n g t o t a l e f f e c t on p l a n t s . T h e i r atmospheric f l u x e s o n t o t h e s o i l on

the

regional

and g l o b a l s c a l e s , j u d g i n g by t h e assessments a v a i l a b l e ,

m i g h t be n e g l e c t e d , s i n c e i n t h e f o r e s e e n significant

changes

future

bring

about

soils.

I n p a r t i c u l a r i t r e f e r e s t o aluminium,

these

fluxes

will

not

i n t h e t o t a l c o n t e n t o f heavy m e t a l s i n the

reserves

of

which

in

and

goes

on

s o i 1s a r e huge. PESTICIDES The w o r l d p e s t i c i d e p r o d u c t i o n has exceeded 5 m l n t l y r , expanding.

These

substances

a r e known t o propagate o v e r g r e a t d i s t a n c e s

c i r c u l a t i n g i n t h e environment, p o o r l y decompose, and biota

considerably

damage

A t t h e same

o f n a t u r a l ecosystems and, i n some cases, human h e a l t h .

t i m e , t h e s c a l e s o f t h e i r a p p l i c a t i , o n i n f o r e s t r y and a g r i c u l t u r e a r e s t i l l expanding.

In

the

for

USA,

axample,

p e s t i c i d e p r o d u c t i o n i n 1946-1976

i n c r e a a s e d f r o m 90,000 t t o 900,000 t. I n s p i t e o f t h i s , c r o p l o s s e s f r o m d e s t r u c t i v e i n s e c t s and

mites

have

n o t reduced, b u t even s l i g h t l y i n c r e a s e d [15]. Year

1904

Crop

9.8

1910-1935

1942-1951

10.5

7.1

1951-1960 12.9

1974 13.0

losses (%) Thus, d e s p i t e expansion o f chemical c o n t r o l , t h e y i e l d d e s t r o y e d i s n o t decreasing.

by

pests

Note t h a t t h i s f a c t i s u s u a l l y d i s g u i s e d b e h i n d apparent

efficiency o f pesticide

application

c r i t e r i a o f a p u r e l y economic n a t u r e .

from

the

point

of

view

of

local

97

A c c o r d i n g t o p r e l i m i n a r y assessments [15], explained

by

the

fact

that

the

applied

this

phenomenon m i g h t

pesticides

be

-

(first

of

all

i n s e c t i c i d e s ) a r e o f t e n more t o x i c f o r n a t u r a l p e s t k i l l e r s t h a n

to

pests

themselves. A p p l i e d a t a c e r t a i n area i n s e c t i c i d e s spread i n t h e atmosphere over

wide

territories,

regulators

of

where

they

inhibit

-

entomophagans

natural

phytophagans. T h i s r e s u l t s i n an i n c r e a s e i n t h e p o p u l a t i o n

numbers o f t h e f o r t h c o m i n g g e n e r a t i o n s o f phytophagans and, hence, expansion

of

the

chemical c o n t r o l .

further

Thus, chemical p e s t c o n t r o l i s " s e l f -

r e p r o d u c i n g " , and man has t o bear t h e expenses t o cause p e s t m o r t a l i t y when entomophagans c o u l d do i t " f r e e o f charge". T h i s problem i s n o t u r g e n t f o r Europe, b u t i s becoming and more for

vast

regions

in

Asia,

A f r i c a , L a t i n America. Therefore we c o n s i d e r

p e s t i c i d e s one of t h e foremost p r i o r i t y problems and

development

of

for

scientific

analysis

s u b s t a n t i a t e d s t r a t e g i e s o f t h e i r a p p l i c a t i o n , though

t h e m a j o r impact of p e s t i c i d e s on v e g e t a t i o n i s n o t a d i r e c t t o x i c but

indirect

-

consumer

vital

destabilization secondary

of

consumer".

the This

trophic

effect,

c h a i n " p r i m a r y producer

scientific

problem

is

-

under

development now i n t h e USSR [ 5 ] . ECOLOGICAL STANDARDIZATION Thus, t h e e f f e c t o f o t h e r w i d e l y spread p h y t o t o x i c p e r o x i a c e t y l n it r a t e s ,

fluorides,

ammonia,

boron,

-

c h l o r i d e , e t h y l e n e , propylene, h y d r o c h l o r i c a c i d

pollutants chlorine,

on

the

[8]

-

hydrogen

regional

and

g l o b a l s c a l e s i s , t o o u r mind, l e s s s i g n i f i c a n t t h a n t h o s e mentioned above: o x i d e s o f s u l p h u r and n i t r o g e n , atmospheric ozone, heavy m e t a l s

in

soils.

and

global

I n s e c t i c i d e s a r e o f p a r t i c u l a r i m p o r t a n c e (see above). It s h o u l d be u n d e r l i n e d once a g a i n t h a t on

scales

both

effecting atmosphere

heavy

plants. induce

the

regional

m e t a l s and ozone p r e s e n t secondary a n t h r o g e n i c f a c t o r s Nitrogen the

oxide

occurrence

emission of

and

distribution

o c c u r r e n c e o f heavy m e t a l s i n d i s s o l v e d t o x i c form i s induced water

acidification

in

the

ozone i n t h e atmosphere, w h i l e t h e by

soil

or

due t o man-induced i n c r e a s e i n t h e c o n t e n t o f s u l p h u r

and n i t r o g e n o x i d e s i n t h e atmosphere.

98

Thus, q u i t e a number o f adverse f a c t o r s a f f e c t and

agrocenoses

natural

1) c a u s i n g g e n e r a l l y speaking,

(Fig.

phytocenoses

various e f f e c t s

a g a i n s t a p a r t i c u l a r e c o l o g i c a l n a t u r a l background. Besides, conditions space

in

characteristics

substances C,

environmental

n a t u r a l ecosystems a r e always v a r i a b l e , as w e l l as t i m e and of

vegetation.

...,Cn , i n p a r t i c u l a r ,

Concentrations

of

phytotoxic

v a r y w i t h time. P l a n t response t o t h e i r

impact depends on p l a n t species, t y p e o f h a b i t a t , and

other

environmental

factors. These p e c u l i a r i t i e s o f a c t u a l e c o l o g i c a l processes a r e t o be accounted f o r i n a t t e m p t s t o e s t a b l i s h e c o l o g i c a l standards. L e t u s c o n s i d e r a f a i r l y common s i t u a t i o n . The v a l u e ( i n d e x ) o f p r i m a r y phytomass

calculated

f o r u n i t area

-

-

this

year's

i s t a k e n as a c r i t e r i o n o f t h e s t a t e

o f ecosystems on a g i v e n t e r r i t o r y S. The acceptable

production

ecosystems

state

is

considred

i f t h e p r i m a r y p r o d u c t i o n P makes up n o t l e s s t h a n (100-N) % of

t h i s i n d e x v a l u e i n t h e absence o f s t r e s s f r o m p o l l u t i o n f a c t o r s . A n a l y s i n g special

ecotoxicological

l i t e r a t u r e and p e r f o r m i n g s p e c i a l i n v e s t i g a t i o n s

one can imagine mean seasonal c o n c e n t r a t i o n o f atmospheric effect

o f which would be r e d u c i n g p l a n t p r o d u c t i v i t y by

N%.

w i l l always be t o a c o n s i d e r a b l e e x t e n t ambiguous. It w i l l on

the

vary

depending

t y p e o f h a b i t a t , species composition o f t h e phytocenosis, c l i m a t i c

f a c t o r s , o t h e r man-made f a c t o r s . Therefore, a

(C ) , t h e 2 cr But t h i s v a l u e

SO

distributed

value

of

the

i t would be c o r r e c t t o

operate

c r i t i c a l l o a d f o r t h e g i v e n t e r r i t o r y S. We

s h a l l assume i t l o g n o r m a l l y d i s t r i b u t e d and i n d i c a t e i t s average

.

logarithm

1nC , and i t s d i s p e r s i o n , u s i n g DC So, what mean seasonal cr cr c o n c e n t r a t i o n o f atmospheric SO c o u l d be recommended as p e r m i s s i b l e (C ) ? 2 P Here one s h o u l d b e a r i n mind t h a t i r r e s p e c t i v e o f t h e a p p l i e d system of using

emission r e s t r i c t i o n , particular,

will

be

the

resulting

varying.

concentration,

seasonal

values

in

That i s , i t would be reasonable t o o p e r a t e

.

a g a i n w i t h t h e d i s t r i b u t e d v a l u e w i t h average 1nC and d i s p e r s i o n DC P DC , The q u e s t i o n o f admiss b i l i t y o f r e l a t i o n s h i p s between 1nC cr cr DC i s a s s o c i a t e d w i t h t h e concept o f a p e r m i s s i b l e r i s k o f t h e o c c u r r e n c e P o f an u n d e s i r a b l e e c o l o g i c a e f f e c t ; i n o u r case, i t i s the primary

,'

production

decrease

over

admissible r e l a t i o n s h i p i s :

N%. I f P i s t h e a d m i s s i b l e r i s k l e v e l , t h e n t h e

99

-

lnCcr

where

1nC

cr

+ DC1 P

The e x p o n e n t i a l m u l t i p l i e r i n t h e r i g h t - h a n d

side

+ DC P, = x

/Dc

cr

x

;

cP

=

cCre - X JD,

P

i s d e f i n e d from m

implies

the

reserve

coefficient

which

indicates

of

how

the much

equation lower

the

p e r m i s s i b l e p o l l u t a n t c o n c e n t r a t i o n has t o be compared t o t h e c r i t i c a l

one

[l] under g i v e n p e r m i s s i b l e e c o l o g i c a l r i s k p. Given t h e i n f o r m a t i o n

,.....Cn

on

the

joint

impact

serveral

pollution

factors

C

critical

( K ) and p e r m i s s i b l e l i m i t s o f t h e t o t a l p o l l u t i o n , t h e e c o l o g i c a l

1

is

available,

is

of

one

in

a

position, t o indentify

r i s k ( 1 e v e l ) p b e i n g s e t f o r t h ( F i g . 2).

CONC LUS I ON A t present, t h e primary p r i o r i t y p o l l u t a n t s from t h e p o i n t o f their

effect

on

t e r r e s t r i a l ecosystems on t h e r e g i o n a l and g l o b a

iew

of

scales

a r e o x i d e s o f s u l p h u r and n i t r o g e n , as w e l l as p e s t i c i d e s . A c i d i f i c a t i o n o f p r e c i p i t a t i o n , induced by emissions o f into

the

atmosphere,

brings

about

changes

in

Besides,

occurrence

t h e r m a l and

of

0

photochemical

3

soil

-

o c c u r r e n c e o f p h y t o t o x i c forms o f m e t a l s i n s o i l

Al,

i n t h e atmosphere due t o NO reactions

results

these

composit on

and

so

on.

Cd,

2.

oxides

and

i n t h e course o f

i n s i g n i t l c a n t (phototoxic)

e f f e c t s when 0

gets i n t o photosynthesising c e l l s . 3 A p a r t i c u l a r r o l e i n t h e atmosphere p o l l u t i o n p l a y

The

current

application

the

insecticides.

o f i n s e c t i c i d e s d e s t a b i l i z e s t h e "host-parasite"

system on t h e c o n t i n e n t a l s c a l e as a r e s u l t o f t h e now accepted s t r a t e g y o f pesticides

application

due

to

the

entomophagans t h a n f o r phytophagans.

fact Note

that that

they on

a r e more t o x i c f o r a

local

scale

the

a p p l i c a t i o n o f chemical p e s t c o n t r o l methods seems e c o n o m i c a l l y expedient. As f o r t h e s c i e n t i f i c problems r e l a t e d t o s u l p h u r and n i t r o g e n emission,

the

p r i m a r y importance:

-

oxides

f o l l o w i n g d i r e c t i o n s i n t h e f i e l d o f a p p l i e d ecology a r e o f

development o f methods t o p r e d i c t r e g i o n a l and g l o b a l l e v e l s o f

100

SO and NO i n t h e atmosphere if t h e s p a t i a l d i s t r i b u t i o n 2 2 o f emission i n t e n s i t i e s a r e known;

- assessment

o f t h e major b i o l o g i c a l e f f e c t s o f SO and NO 2 2 w i t h due account o f t h e i r impact on p h o t o s y n t h e s i z i n g c e l l s , as we1 1 as consequences of p r e c i p i t a t i o n a c i d i f i c a t i o n and a s s o c i a t e d i n d u c t i o n o f p h y t o t o x i c forms of m e t a l s i n s o i l s a f f e c t i n g r o o t t r a n s p o r t ; assessment o f t h e e f f e c t o f NO photosynthesizing c e l l s ;

-

2

induced ozone on

development o f methods t o e s t i m a t e c r i t i c a l and p e r m i s s i b l e c o n c e n t r a t i o n o f these p o l l u t a n t s and t h e i r complexes i n t h e environment proceeding from t h e e s t a b l i s h e d maximum p e r m i s s i b l e e c o l o g i c a l e f f e c t and t h e r i s k o f i t s excedence; t h e d i f f e r e n c e between c r i t i c a l and p e r m i s s i b l e impacts (which i m p l y such n o t i o n s as zone o f reserve, r e s e r v e c o e f f i c i e n t

-

t h e p o r t i o n o f t h e p e r m i s s i b l e l e v e l beyond t h e c r i t i c a l l e v e l )

happens t o be a f u n c t i o n o f t h e maximum p e r m i s s i b l e r i s k l e v e l . Solution formulating

of

these

questions

research of

problems

inter-state

might

create

coordination

a

basis

related

to

for

maximum

p e r m i s s i b l e l e v e l s o f occurrence o f adverse e c o l o g i c a l e f f e c t s and r e l e v a n t levels

of

ecological

risk.

However, c o o r d i n a t i o n o f these problems on a

b i l a t e r a l o r m u l t i l a t e r a l b a s i s comes w i t h i n t h e

sphere

of

international

economic r e l a t i o n s and p o l i t i c a l a c t i v i t i e s . REFERENCES

1.

I z r a e l Yu.A. L.,

2.

Ecology and Natural Environment S t a t e Control.

Gidrometeoi zdat,

Insarov G.,

-

1985.

F i l i p p o v a L. Methodology o f assessment and p r e d i c t i o n

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I n : Problems o f

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Insarova I.D.

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p. 33-49.

Gidrometeoizdat,

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4.

Insarova. I.D.

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I n : Problems

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Yu.A.Izrae1,

L.M.

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In:

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14. Jacobson J.S.

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-

Leningrad, Gidrometeoizdat,

1985, p. 7-20.

103

Fig.1 Primary factors

I Primary factors

Insecticides

1

Destabilization of the system "1 st-order consumer-2nd-order consumer"

so2

H+

Acid deposition

Root transport affection

phytotoxic forms of heavy metals, change in soil chemical composition

-

104

Fig. 2

I\\\\\\\\\

0

\

T. Schneider (Editor)/Acidificatwn and its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

105

THE ECONOMIC IMPACT OF ACIDIFICATION* Lars Bergman** Stockholm School of Economics

ABSTRACT The economic impact of acidification can be looked upon in two perspectives. The first is to focus on the economic losses caused by acid depositions. The second is to focus on the economic impact of policy responses to the acidification problem. Recent estimates of the economic losses caused by acid deposition are uncertain, but suggest that these losses can turn out to be significant. Due to international positive external effects of emission reductions in individual countries,coordination o f emission control policies in Europe can lead to significant cost savings. INTRODUCTION The purpose of this paper is to review the economic aspects of acidification To begin with I will try to identify the types of economic issues which seem to be relevant in this particular context, and to summarize the state of our knowledge about the economic impact o f acidification. Then I will focus on the economic efficiency aspects of emission control policies. On the basis of some preliminary findings I will make two propositions. The first is that coordination of emission control policies in Europe can lead to significant cost reductions for the cooperating countries. The second is that efficient multicountry coordination of emission control policies calls for a system of cost-sharing between the countries. STRUCTURE OF THE PROBLEM The economic impact of acidification can be considered in at least two different perspectives. The first is to focus on the effects of acid depositions on the availability of scarce resources such as forestry, fishery and agricultural products, manpower, recreation opportunities and other aspects of environmental quality. The second is to focus on the economic aspects of policy responses to the acidification problem. That is, the costs

THE

* The author is grateful to Karl-Goran Maler for valuable comments and inspiring ideas. Research assistance by Kerstin Amberg and financial support by the Swedish Environmental Protection Board is gratefully acknowledged. ** Professor of economics.

106 and b e n e f i t s o f e m i s s i o n c o n t r o l p o l i c i e s . Moreover, t h e d i s c u s s i o n on t h e s e matters can be confined t o d i r e c t effects, various i n d i r e c t , o r general equilibrium,

o r i t can b e extended t o i n c l u d e effects.

DIRECT EFFECTS OF A C I D DEPOSITION The d i r e c t e f f e c t s o f a c i d d e p o s i t i o n

on t h e a v a i l a b i l i t y o f e n v i r o n m e n t a l

and o t h e r s c a r c e r e s o u r c e s work t h r o u g h i m p a c t s on f o r e s t ecosystems, a g r i c u l t u r a l p r o d u c t i v i t y , a q u a t i c ecosystems, human h e a l t h , h i s t o r i c a l monuments, m a t e r i a l s and b u i l d i n g s . I n o r d e r t o make t h e s e e f f e c t s comparable t o each o t h e r , and t o t h e c o s t s o f r e d u c i n g emissions, t h e y s h o u l d be expressed i n monetary u n i t s . B e f o r e t h a t can be done, however, two problems have t o b e s o l v e d . The f i r s t i s t h a t t h e p h y s i c a l e f f e c t s o f a c i d i f i c a t i o n have t o be i d e n t i f i e d and q u a n t i f i e d . The second i s t h a t t h e q u a n t i f i e d p h y s i c a l e f f e c t s have t o be expressed i n monetary u n i t s . The c u r r e n t s t a t e o f knowledge i s such t h a t any monetary measure o f t h e damage caused b y a c i d d e p o s i t i o n

i s h i g h l y u n c e r t a i n . To some e x t e n t t h i s

i s due t o t h e d i f f i c u l t y o f a p p l y i n g t h e o r e t i c a l l y s a t i s f a c t o r y measures o f t h e c o s t o f reduced a v a i l a b i l i t y o f p u b l i c goods such -as e n v i r o n m e n t a l q u a l i t y and h i s t o r i c a l monuments. The m a i n s o u r c e o f u n c e r t a i n t y , however, i s t h e u n c e r t a i n t y about t h e p h y s i c a l damage caused by a c i d d e p o s i t i o n . I n s p i t e o f t h e s e d i f f i c u l t i e s s e v e r a l a t t e m p t s t o e s t i m a t e t h e economic l o s s e s caused b y a c i d d e p o s i t i o n

have been made. J u s t t o m e n t i o n one example,

Crocker ( r e f . 1) e s t i m a t e d t h e s e l o s s e s t o be 5.1 b i l l i o n 1978 US$ p e r annum f o r t h e eastern p a r t o f t h e U n i t e d States. A s i g n i f i c a n t share o f t h e e s t i mated l o s s e s , 2 b i l l i o n US$ was due t o damage t o m a t e r i a l s . As I i n d i c a t e d before, t h i s and s i m i l a r e s t i m a t e s a r e v e r y u n c e r t a i n . Y e t i t i s o b v i o u s t h a t t h e economic l o s s e s due t o a c i d d e p o s i t i o n

and t h u s t h e p o t e n t i a l

b e n e f i t s o f e m i s s i o n c o n t r o l , m i g h t t u r n o u t t o be q u i t e s i g n i f i c a n t . Our p r o b l e m t o d a y i s t h a t we do n o t know t h e p r o b a b i l i t y o f such an outcome. INDIRECT EFFECTS OF ACID DEPOSITION If acid deposition

s i g n i f i c a n t l y reduces t h e a v a i l a b i l i t y o f various

s c a r c e r e s o u r c e s , t h a t i s most l i k e l y t o have i n d i r e c t e f f e c t s on r e s o u r c e a l l o c a t i o n and income d i s t r i b u t i o n i n s e v e r a l c o u n t r i e s . I n t h e e c o n o m i s t ' s j a r g o n t h e r e w i l l be s o - c a l l e d g e n e r a l e q u i l i b r i u m e f f e c t s . A case i n p o i n t i s t h e f o r e s t dieback which p o s s i b l y i s , a t l e a s t t o some e x t e n t , caused by a c i d d e p o s i t i o n : I n t h e s h o r t r u n damage

t o t h e standing f o r e s t tend t o create excessive

c u t t i n g s and t h u s an i n c r e a s e d t i m b e r s u p p l y . T h i s w i l l produce a downward p r e s s u r e on t i m b e r p r i c e s , and t h u s t e r m s - o f - t r a d e

losses t o c o u n t r i e s who

107

a r e n e t e x p o r t e r s o f t i m b e r . The t e r m s - o f - t r a d e

g a i n s t o c o u n t r i e s who a r e

n e t importers o f timber i s t h e o t h e r side o f t h e coin. I n t h e l o n g r u n t h e f o r e s t damages i m p l y reduced p r o d u c t i v i t y i n f o r e s t r y and t h u s s m a l l e r s u p p l y o f t i m b e r . The r e s u l t s h o u l d be an upward p r e s s u r e on t i m b e r p r i c e s , and t e r m s - o f - t r a d e o f timber. T h i s terms-of-trade

g a i n s t o c o u n t r i e s who a r e n e t e x p o r t e r s

g a i n may o r may n o t compensate t h e l o s s caused

b y t h e reduced f o r e s t r y p r o d u c t i v i t y . I b e l i e v e i t i s i m p o r t a n t t o be aware o f p o t e n t i a l g e n e r a l e q u i l i b r i u m

e f f e c t s o f damages caused b y a c i d d e p o s i t i o n . A t t h e c u r r e n t s t a t e o f knowledge, however, i t i s n o t p o s s i b l e t o make r e a s o n a b l e q u a n t i f i c a t i o n s o f t h e s e e f f e c t s . S i n c e r e s e a r c h a c t i v i t i e s on t o p i c s o f t h i s s o r t a r e under way, t h e s i t u a t i o n m i g h t be q u i t e d i f f e r e n t i n a few y e a r s t i m e . DIRECT AND INDIRECT EFFECTS OF POLICY RESPONSES TO ACIDIFICATION The p o l i c y responses t o a c i d i f i c a t i o n i n c l u d e t h e i m p l e m e n t a t i o n o f a number o f measures such as f u e l s w i t c h i n g , f u e l c l e a n i n g and f l u e gas des u l p h u r i z a t i o n . There a r e t h r e e t y p e s o f economic consequences o f t h e s e p o l i c y responses. The f i r s t i s t h e b e n e f i t damage caused b y a c i d d e p o s i t i o n .

i n terms o f r e d u c t i o n s o f t h e

F o r t h e reasons mentioned b e f o r e t h e

magnitude o f t h i s b e n e f i t i s u n c e r t a i n . The second i s t h e i n s t a l l a t i o n c o s t o f t h e r e s o u r c e s used f o r e m i s s i o n r e d u c t i o n purposes. A l t h o u g h t h e r e i s some disagreement about t h e c o s t o f r e d u c i n g SOx and NOx e m i s s i o n s , t h e c o s t e s t i m a t e s a r e a l o t l e s s u n c e r t a i n t h a n t h e b e n e f i t e s t i m a t e s . T h i s i s i n f a c t one o f t h e key problems i n t h e context o f emission c o n t r o l p o l i c i e s . I n a d d i t i o n t o t h e d i r e c t b e n e f i t s and c o s t s o f e m i s s i o n c o n t r o l p o l i c i e s , t h e r e a r e i n d i r e c t , o r g e n e r a l e q u i l i b r i u m , e f f e c t s . One example i s t h a t s h i f t s i n demand f r o m h i g h s u l p h u r t o l o w s u l p h u r c o a l

can have s i g n i f i c a n t

e f f e c t s on r e l a t i v e c o a l p r i c e s as w e l l as on t h e economic c o n d i t i o n s i n r e g i o n s where incomes and employment a r e h e a v i l y dependent on c o a l m i n i n g . There a r e a number o f s t u d i e s about t h e c o s t o f e m i s s i o n c o n t r o l . ’ ) going i n t o d e t a i l

Without

i t i s c l e a r t h a t t h e r e are i n general s i g n i f i c a n t costs

a s s o c i a t e d w i t h m a j o r e m i s s i o n r e d u c t i o n s . The r e l e v a n t q u e s t i o n , however, i s n o t whether e m i s s i o n c o n t r o l c o s t s a r e h i g h o r low, b u t whether t h e b e n e f i t s a r e l a r g e enough t o j u s t i f y t h e c o s t s . From an economic e f f i c i e n c y p o i n t o f v i e w a d d i t i o n a l e m i s s i o n r e d u c t i o n s a r e j u s t i f i e d as l o n g as t h e m a r g i n a l c o s t o f e m i s s i o n c o n t r o l does n o t exceed t h e r e s u l t i n g m a r g i n a l benefit.

7 ) OECD (-ref. 2 ) was t h e f i r s t m a j o r s t u d y on t h i s t o p i c .

108 A t t h e c u r r e n t s t a t e of knowledge t h e e x a c t i m p l i c a t i o n s of t h i s d e c i s i o n r u l e , i n t e r m s of e m i s s i o n r e d u c t i o n s i n d i f f e r e n t c o u n t r i e s , cannot e a s i l y be a s c e r t a i n e d :

Yet i t i s c l e a r t h a t economic e f f i c i e n c y i s a v e r y i m p o r t a n t

a s p e c t o f e m i s s i o n c o n t r o l p o l i c i e s . What i s l e s s c l e a r , however, i s t h a t emission c o n t r o l p o l i c i e s t h a t

a r e e c o n o m i c a l l y e f f i c i e n t i n a European

p e r s p e c t i v e a r e n o t l i k e l y t o be implemented u n l e s s two s p e c i f i c problems a r e s o l v e d . I n o r d e r t o s u b s t a n t i a t e t h i s s t a t e m e n t Iw i l l b r i e f l y d i s c u s s t h e c o n d i t i o n s f o r e f f i c i e n t emission c o n t r o l i n a m u l t i c o u n t r y perspective. ECONOMICALLY EFFICIENT E M I S S I O N CONTROL I N A MULTICOUNTRY PERSPECTIVE L e t us, f o r t h e moment, s i m p l i f y m a t t e r s and assume t h a t b o t h b e n e f i t s and c o s t s o f e m i s s i o n c o n t r o l measures can be a c c u r a t e l y measured and expressed i n monetary u n i t s . F u r t h e r m o r e , l e t us assume t h a t e m i s s i o n c o n t r o l p o l i c i e s a r e d e s i g n e d on t h e b a s i s o f economic e f f i c i e n c y c o n s i d e r a t i o n s o n l y . Under t h e s e e x t r e m e l y s i m p l i f i e d c o n d i t i o n s each i n d i v i d u a l c o u n t r y would implement e m i s s i o n c o n t r o l measures t o t h e p o i n t where t h e m a r g i n a l c o s t o f a d d i t i o n a l e m i s s i o n r e d u c t i o n s , MC,

i s equal t o t h e marginal b e n e f i t t o t h e country

o f t h e r e s u l t i n g d e p o s i t i o n r e d u c t i o n , MBH. I n o t h e r words t h e implemented measures would s a t i s f y t h e c o n d i t i o n

MC = MBH However, as i s e v i d e n t f r o m t h e EMEP documentation o f t h e atmospheric t r a n s p o r t a t i o n p a t t e r n s f o r s u l p h u r d i o x i d e e m i s s i o n s i n Europe, e m i s s i o n r e d u c t i o n s i n one c o u n t r y w i l l produce d e p o s i t i o n r e d u c t i o n s i n s e v e r a l c o u n t r i e s . I n t h e economist's j a r g o n t h e r e a r e i n t e r n a t i o n a l p o s i t i v e external e f f e c t s o f e m i s s i o n c o n t r o l measures i n each i n d i v i d u a l c o u n t r y . T h i s means t h a t t h e t o t a l m a r g i n a l b e n e f i t s o f e m i s s i o n c o n t r o l can be s u b d i v i d e d i n t o two p a r t s . The f i r s t i s MEH, t h e b e n e f i t s t o t h e c o u n t r y w h i c h r e d u c e s i t s e m i s s i o n s . The second i s MBO, t h e b e n e f i t s t o a l l c o u n t r i e s i n w h i c h d e p o s i t i o n s a r e reduced as a r e s u l t o f t h e e m i s s i o n r e d u c t i o n s

i n q u e s t i o n . Thus, f r o m t h e p o i n t o f view o f a c o a l i t i o n o f c o u n t r i e s , e m i s s i o n s s h o u l d b e reduced t o a p o i n t where

MC = MBH + MBO I f a l l c o u n t r i e s i n t h e c o a l i t i o n a c t u a l l y adopt t h i s r u l e t h e n e t b e n e f i t s

f o r t h e c o a l i t i o n i s maximized. B u t t h i s d e c i s i o n r u l e a l s o i m p l i e s t h a t each i n d i v i d u a l c o u n t r y i n t h e c o a l i t i o n s h o u l d c a r r y e m i s s i o n r e d u c t i o n s t o a p o i n t where t h e m a r g i n a l c o s t o f e m i s s i o n c o n t r o l exceeds t h e r e s u l t i n g

109

marginal benefit to itself, i.e. to a point where MC > MBH. This observation points at a couple of problems in connection with international emission control policies. In the following I will denote these problems "the enforcability problem" and "the cost-sharing problem". THE ENFORCABILITY PROBLEM In generalsagreements between countries cannot be enforced in the same way as agreements between firms or individuals. Let us therefore consider the incentives for individual countries t o adhere to agreements on coordination of emission control policies. The numerical example in Table 1 illustrates the problem. There are two countries, 1 and 2, forming a coalition in order to coordinate emission control policies. Both countries have emission control options producing marginal benefits to the coalition in excess of their marginal costs. However, in all cases the marginal cost of emission control exceeds the marginal benefit to the country implementing the measures in question. TABLE 1 CHOICE OF EMISSION CONTROL STRATEGY IN INDIVIDUAL COUNTRIES: PRISONERS' DILEMMA Country Cost of Benefit Benefit

1 emission reduction t o country 1 to country 2

: 100 : :

Country 2 Cost o f emission reduction : Benefit t o country 2 : Benefit to country 1 : Payoff matrix for strategies a (adhere) and

S

t a r l a t e !3b Y

a (50,5O)

(75,-25)

2 Strategy

b

(-25,75)

75 75

100

75 75 b (break)

110

It is assumed that the agreement between the two countries cannot be legally enforced. In view of this both countries are faced with a choice between two strategies, a and b. The first, strategy a, is to adhere to the agreement, and the other, strategy b, is to, more or less secretly, break the agreement. Under these conditions each country is faced with a problem which is similar to the famous "Prisoner's dilemma": From the point of view of the coalition, the preferred outcome is that both countries adopt strategy a. The problem is, however, that both countries, acting in their own interest, tend to choose strategy b; for any choice of strategy by the other country each country can secure a larger payoff to itself by breaking the agreement. In other words b is a dominating strategy for both countries. Thus the inferior outcome (0,0) is a possible result in spite of the fact that (50, 50) is a better outcome for both countries. This suggests that potential gains from coordinated action is not a sufficient condition for coordinated action to actually take place. Some kind of institutional arrangement for enforcement of agreements seems to be needed as well. THE COST-SHARING PROBLEM Another type of problem in connection with international coordination of emission control policies is illustrated in Table 2. Here it is assumed that international agreements can be enforced. Again coordinated action would be beneficial for the coalition of country 1 and country 2. However, unless there is a cost-sharing arrangement between the countries, country 2 would make a net loss by joining the coalition. Without coordination with country 2, country 1 prefers to refrain from implementing the emission control measures. Thus the outcome (0,0) is possible in spite o f the fact that the outcome (25, -10) could be shared in such a way that both countries would be better off. TABLE 2 CHOICE OF EMISSION CONTROL STRATEGY IN INDIVIDUAL COUNTRIES: UNEQUAL DISTRIBUTION OF POTENTIAL GAINS Country Cost of Benefit Benefit

1

emission reduction : to country 1 to country 2

100

95 15

111 Country 2 Cost o f emission r e d u c t i o n

:

100

Benefit t o country 2

75

Benefit t o country 1

30

P a y o f f m a t r i x f o r s t r a t e g i e s a ( a d h e r e ) and b ( b r e a k )

2 S t r a I t e 9 Y

a a

(25, -10)

b

(30,-25)

Strategy

b (-5,151

(030)

These s i m p l e examples suggest t h a t e f f i c i e n t i n t e r n a t i o n a l c o o r d i n a t i o n o f e m i s s i o n c o n t r o l p o l i c i e s r e q u i r e s an i n s t i t u t i o n a l framework w i t h i n w h i c h i n t e r n a t i o n a l agreements can be enforced and c o s t - s h a r i n g arrangements d e s i g n e d and implemented. However, t h e p r a c t i c a l importance o f t h i s i s s u e t o a v e r y l a r g e e x t e n t depends on t h e magnitude o f t h e g a i n s f r o m c o o r d i n a t e d a c t i o n . B e f o r e t u r n i n g t o t h a t i s s u e , however, t h e problem o f d e f i n i n g oper a t i o n a l goals f o r i n t e r n a t i o n a l c o o r d i n a t i o n o f emission c o n t r o l p o l i c i e s

has t o b e d i s c u s s e d . OPERATIONAL GOALS FOR E M I S S I O N CONTROL POLICIES

So f a r I have d i s c u s s e d p o t e n t i a l c o o r d i n a t i o n g a i n s i n terms o f n e t b e n e f i t s . As I have a l r e a d y i n d i c a t e d , however, t h e b e n e f i t e s t i m a t e s a r e i n h e r e n t l y u n c e r t a i n . Ongoing r e s e a r c h w i l l p r o b a b l y reduce o r e l i m i n a t e some o f t h e u n c e r t a i n t i e s . B u t i t seems t o be r e a s o n a b l e t o assume t h a t p r a c t i c a l e m i s s i o n c o n t r o l p o l i c i e s cannot, o r a t l e a s t w i l l n o t , be based on m o n e t a r y measures o f t h e n e t b e n e f i t s o f e m i s s i o n c o n t r o l measures i n t h e near f u t u r e . T h i s does n o t mean t h a t t h e r e i s no room f o r economic e f f i c i e n c y c o n s i d e r a t i o n s when e m i s s i o n c o n t r o l p o l i c i e s a r e d e s i g n e d and implemented. I t o n l y means t h a t we have t o f o c u s on e m i s s i o n c o n t r o l c o s t s and c o s t - e f f e c t i v e n e s s c o n s i d e r a t i o n s . We can t h e n d i s t i n g u i s h t w o t y p e s o f c o s t - e f f e c t i v e n e s s problems.

112

The first emerges once a target emission reduction has been determined for an individual country. The problem then is to identify the set of emission control measures that makes it possible to attain the target emission level at the lowest possible cost. A closely related problem is to design an institutional framework and a set of environmental policy measures which are conducive for cost-effectiveness in national emission control policies. It would take me to far to go into details in this issue. Yet it is worth mentioning that various attempts in the U.S. to allow trade in so called emission permits have led to considerable cost savings. (See ref. 3). The second type of cost-effectiveness problem emerges if a group of countries agree on a set of deposition standards, or target deposition reductions, for each country. These deposition standards would then reflect current knowledge about the physical damage caused by acid deposition, as well as estimates o f the economic losses which these physical damages represent. The deposition standards could also differ across countries. The problem then is to identify the set of emission reductions in the individual countries which would minimize the overall cost to attain the agreed upon deposition standards. Thus, the emission reductions in individual countries would be determined through agreements between the countries on the basis of cost-effectiveness considerations. For a group of countries such agreements can lead to cost savings. The question then is how big these cost savings might be. THE MAGNITUDE OF POTENTIAL COST SAVING In order to estimate the potential cost savings we are concerned with, one needs to know the relation between emission reductions and '(minimum) emission control costs in individual countries. Although our current knowledge about the costs of emission control is less uncertain than our knowledge about the benefits of emission control, it is still insufficient to allow us to carry out the desired calculations with a reasonable degree of precision. However, in order to get a very rough first estimate o f the magnitude of possible gains from international coordination of emission control policies, I have carried out some simple calculations. The point of departure is the EMEP,so called source-receptor matrix (see ref. 4) which gives estimates on how emission reductions in individual countries lead to deposition reductions in the home country as well as in other countries. In order t o simplify matters as much as possible i t is assumed

113 t h a t t h e m a r g i n a l c o s t o f e m i s s i o n r e d u c t i o n i n 27 European c o u n t r i e s i s c o n s t a n t , and equal a c r o s s a l l c o u n t r i e s , up t o a maximum r e d u c t i o n l e v e l c o r r e s p o n d i n g t o 30 % o f i n i t i a l e m i s s i o n s i n each c o u n t r y . Beyond t h a t l e v e 1 , e m i s s i o n r e d u c t i o n s a r e assumed t o become i n f i n i t e l y c o s t l y . Moreover, i t i s assumed t h a t t h e r e i s an agreed upon d e p o s i t i o n r e d u c t i o n t a r g e t f o r

each c o u n t r y . F o r each i n d i v i d u a l c o u n t r y t h i s t a r g e t d e p o s i t i o n r e d u c t i o n i s s e t equal t o t h e d e p o s i t i o n r e d u c t i o n a t t a i n e d b y r e d u c i n g domestic e m i s s i o n s by 30%, w h i l e a l l o t h e r c o u n t r i e s m a i n t a i n t h e i r i n i t i a l e m i s s i o n levels. From t h e p o i n t o f v i e w o f an i n d i v i d u a l c o u n t r y two extreme cases can be i d e n t i f i e d under t h e s e c o n d i t i o n s . I n t h e f i r s t t h e t a r g e t d e p o s i t i o n r e d u c t i o n f o r t h e c o u n t r y i n q u e s t i o n i s a t t a i n e d b y independent a c t i o n . I n t h e second t h e c o u n t r y j o i n s a grand c o a l i t i o n w i t h a l l o t h e r 26 c o u n t r i e s . T h i s would be a c o a l i t i o n i n w h i c h e m i s s i o n c o n t r o l p o l i c i e s a r e c o o r d i n a t e d i n such a way t h a t t h e t o t a l c o s t o f s i m u l t a n o u s l y a t t a i n i n g t h e d e p o s i t i o n t a r g e t s i n a l l c o u n t r i e s a r e m i n i m i z e d , and c o s t s a v i n g s a r e shared i n such a way t h a t each c o u n t r y i n t h e c o a l i t i o n g e t s t h e same p r o p o r t i o n a l c o s t reduction. Under t h e assumed c o n d i t i o n s i t t u r n s o u t t h a t t h e c o s t s a v i n g which can b e a t t a i n e d t h r o u g h c o o r d i n a t e d a c t i o n i s more t h a n 40 % o f t h e c o s t o f a t t a i n i n g t h e t a r g e t d e p o s i t i o n r e d u c t i o n b y independent a c t i o n . Moreover, t h i s a l s o h o l d s under a l t e r n a t i v e assumptions about e m i s s i o n c o n t r o l c o s t s i n t h e d i f f e r e n t c o u n t r i e s . O f c o u r s e t h e s e r e s u l t s s h o u l d be r e g a r d e d as v e r y p r e l i m i n a r y . Yet i t seems q u i t e r e a s o n a b l e t o conclude t h a t p o t e n t i a l g a i n s f r o m c o o r d i n a t e d a c t i o n a r e l i k e l y t o be q u i t e s i g n i f i c a n t . Recent studies i n t h e United States ( r e f . 5) support t h i s conclusion. CONCLUDING REMARKS The economics o f a c i d i f i c a t i o n i s b e s e t w i t h u n c e r t a i n t i e s . Yet economic a n a l y s i s and r o u g h c a l c u l a t i o n s seem t o l e a d t o a c o u p l e o f q u i t e s t r o n g p o l i c y c o n c l u s i o n s . The f i r s t i s t h a t t h e r e i s a case f o r a i m i n g a t c o s t e f f e c t i v e n e s s i n n a t i o n a l as w e l l as i n t e r n a t i o n a l e m i s s i o n c o n t r o l p o l i c i e s . I n g e n e r a l t h i s i s s i m p l y because t h e more e f f i c i e n t

r e s o u r c e s a r e used

f o r e m i s s i o n c o n t r o l purposes, t h e more e m i s s i o n r e d u c t i o n can be a t t a i n e d f o r a g i v e n amount o f r e s o u r c e s . Moreover, r o u g h c a l c u l a t i o n s as w e l l as recent studies

suggest t h a t t h e s e g a i n s can indeed be s i g n i f i c a n t .

114 The o t h e r c o n c l u s i o n i s t h a t an i n s t i t u t i o n a l framework which i s conducive f o r i n t e r n a t i o n a l c o o p e r a t i o n i s needed. More p r e c i s e l y , c o s t - e f f e c t i v e c o o r d i n a t i o n o f emission c o n t r o l p o l i c i e s has t o be based on a s e t o f enf o r c a b l e agreements, i n c l u d i n g a f o r m u l a f o r s h a r i n g t h e c o s t s o f emission c o n t r o l . A f i r s t s t e p i n t h i s d i r e c t i o n would be t o change t h e focus i n emission c o n t r o l p o l i c i e s f r o m emission r e d u c t i o n s t o d e p o s i t i o n r e d u c t i o n s , and t o i n i t i a t e a major r e s e a r c h program on t h e c o s t s o f emission c o n t r o l i n t h e European c o u n t r i e s . REFERENCES 1 2 3 4 5

T.D. Crocker, Estimates o f A c i d D e p o s i t i o n C o n t r o l B e n e f i t s : A Bayesian P e r s p e c t i v e , i n Mandelbaum, P. (ed.) A c i d Rain. Economic Asessment, Plenum Press, New York, 1985. The Costs and B e n e f i t s o f Sulphur Oxide Control, OECD, P a r i s , 1981. T.H. Tietenberg, Emission T r a d i n g . An e x e r c i s e i n r e f o r m i n g emission c o n t r o l p o l i c y . Resources f o r t h e Future, Washington D.C., 1985. J. Lemhaus, J Saltbones and A. Eliassen, D e p o s i t i o n p a t t e r n s and t r a n s p o r t s e c t o r a n a l y s i s f o r a f o u r y e a r period, EMEP/MSC-W Report 1/85, The Norweg i a n M e t e o r o l o g i c a l I n s t i t u t e , Oslo. D.G. S t r e e t s , D.A. Hansson and L.D. C a r t e r , Targeted S t r a t e g i e s f o r C o n t r o l o f A c i d Deposition, Journal o f t h e A i r P o l l u t i o n C o n t r o l A s s o c i a t i o n , December 1984, Vol. 34, No. 12, pp. 1187-1197.

T. Schneider (Editor)/Acidification and its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

117

CHARACTERISTICS OF TREES PREDISPOSED TO DIE R.H. WARING College of Forestry, Oregon State University, Corvallis, OR., U.S.A. 97331

ABSTRACT A tree dies when it is unable to mobilize sufficient resources internally, or obtain additional resources through leaves and roots to sustain life or heal injuries. Although stress of any kind affects the availability of water, nutrients, and photosynthate, we can judge a tree’s probability of dying by assessing:(l) reduction in photosynthesis, (2) adjustments in maintenance costs, and ( 3 ) diversions of photosynthate away from expected growth patterns. Examples are provided for trees subjected to drought, mechanical abrasion, and nutrient stress. I N TRO D U CTIO N

Around the world, there is increasing interest as tc why large groups of trees or whole forests may suddenly die, sometimes without apparent changes in weather or other conditions. Tree physiologists that study stressed or injured trees usually find some degree of abnormalities in the rates of various processes and in the way that resources are allocated. The extent of abnormalities indicates the probability that a tree will sustain life or die. In a general sense, stressed or injured trees alter their carbon balance in three ways: (1) by reducing photosynthesis, (2) by adjusting maintenance costs, or ( 3 ) by diverting photosynthate away from expected patterns of allocation. These changes in carbon balance usually are associated with concomitant changes in nutrition and water balance. The relative importance of water and nutrition, as we shall see, is reflected in the way that the carbon balance is adjusted in stressed plants. Recently, in areas where forest decline and death are widespread, some preliminary physiological studies have been initiated. In reviewing these studies we learn how different kinds of environmental stresses affect the three major

118 c o m p o n e n t s o f t h e c a r b o n b u d g e t . B e f o r e g o i n g t o s p e c i f i c cases, however,

I s h a l l f i r s t r e v i e w t y p i c a l tree r e s p o n s e .

TYPICAL TREE RESPONSE F o r e s t e r s h a v e r e c o g n i z e d normal h e a l t h y trees e x h i b i t a c e r t a i n p e r c e n t a g e of l i v i n g f o l i a g e d i s t r i b u t e d i n a symmetri-

c a l m a n n e r a r o u n d a n d a l o n g p a r t of t h e b o l e . They h a v e c h a r a c t e r i z e d t h e d i s t r i b u t i o n o f wood g r o w t h a l o n g t h e b o l e s o t h a t m e a s u r e m e n t s made a t t h e b a s e c a n be u s e d t o e s t i m a t e g r o w t h throughout t h e length.

E c o l o g i s t s h a v e expanded t h e s e k i n d s of

r e l a t i o n s h i p s t o estimate growth and t o t a l biomass of branches a n d l a r g e d i a m e t e r r o o t s ( r e f . 1 ) . Maximum c a n o p y l e a f a r e a h a s b e e n estimated f r o m c o r r e l a t i o n s w i t h t h e c r o s s - s e c t i o n a l

area

of sapwood ( r e f . 2 ) . T r e e s , p a r t i c u l a r l y t e m p e r a t e s p e c i e s , show a s e a s o n a l phasing i n t h e production of shoots, s t e m s , roots, s t o r a g e

reserves, a n d d e f e n s i v e compounds ( r e f . 3 ) . D u r i n g t h e e l o n g a t i o n o f new s h o o t s , t h e p r o d u c t i o n o f o t h e r m a t e r i a l s i s g r e a t l y

limited,

a n d i n t h e case o f s t o r a g e r e s e r v e s , d e p l e t e d . T h e r e -

f o r e , a n y a b n o r m a l e v e n t t h a t c a u s e s d e f o l i a t i o n , b e it d r o u g h t , f r o s t , o r h e r b i v o r y h a s i t s maximum i m p a c t a t t h e t i m e of s h o o t e x p a n s i o n when r e s e r v e s a r e m i n i m a l . I n f o r e s t s t a n d s , s m a l l t r e e s g r o w i n g i n t h e s h a d e of l a r g e r o n e s may b e p a r t i c u l a r l y s u s c e p t i b l e t o d r o u g h t and d e f o l i a t i o n b e c a u s e t h e i r r e s e r v e s are less t h a n normal

(ref. 4 )

and t h e i r root systems are a l s o r e s t r i c t e d i n r e l a t i o n t o t h e i r s i z e ( r e f . 5, r e f .

6 ) . Large trees, on t h e o t h e r hand, have

t h e i r c a n o p i e s more e x p o s e d t o f r o s t damage, i c e or snow b r e a k age, and a t m o s p h e r i c p o l l u t a n t s . T o assess t h e g e n e r a l p h y s i o l o g i c a l s t a t u s of a t r e e ’ s

c a r b o n b a l a n c e , i t i s d e s i r a b l e t o c o m p a r e a t common r e l a t i v e g r o w t h r a t e s . F o r t h i s r e a s o n c o m p a r i s o n s a r e o f t e n made when g r o w t h p r o c e s s e s h a v e s l o w e d or r e a c h e d a minimum. T h u s ,

just

b e f o r e buds b r e a k c a r b o h y d r a t e and n u t r i e n t r e s e r v e s i n t w i g s , o l d e r f o l i a g e , s t e m , a n d l a r g e diameter r o o t s may b e good i n d i c e s o f f u t u r e g r o w t h a n d t h e a b i l i t y of a t r e e t o r e c o v e r from d e f o l i a t i o n ( r e f . 7 , r e f . 8 ) . Any r e d u c t i o n i n n e t p h o t o s y n t h e s i s by t h e c a n o p y may b e d e t e r m i n e d by c o m p a r i n g c h a n g e s i n wood p r o d u c t i o n by i n d i v i d u a l branches

( r e f . 9 ) . To s u s t a i n p h o t o s y n t h e s i s , t r e e s g r o w i n g o n

119 i n f e r t i l e s o i l s a l l o c a t e a l a r g e r p r o p o r t i o n of p h o t o s y n t h a t e t o r o o t g r o w t h t h a n d o t h o s e g r o w i n g on more f e r t i l e s u b s t r a t e s (ref. 4,

ref. 10).

A tree’s i n a b i l i t y t o accumulate r e s e r v e s o r produce defen-

s i v e compounds i s a s s o c i a t e d w i t h a low p r o d u c t i o n of s t e m wood p e r u n i t o f f o l i a g e . Stem g r o w t h i s a component less c r i t i c a l t o

tree s u r v i v a l t h a n f o l i a g e a n d r o o t g r o w t h , t h u s i t s s e n s i t i v i t y t o c h a n g e s i n t h e r e l a t i v e a v a i l a b i l i t y of r e s o u r c e s ( r e f 1 1 ) . A s a t r e e g r o w s , i t s crown e x p a n d s a n d b e g i n s t o s h a d e o t h e r

trees.

I n a f o r e s t , wood p r o d u c t i o n p e r u n i t of f o l i a g e t h e r e -

f o r e d e c r e a s e s a s t h e t o t a l canopy l e a f a r e a i n c r e a s e s . Once a f o r e s t r e a c h e s maximum c a n o p y , some t r e e s c o n t i n u e t o d e v e l o p more canopy w h i l e o t h e r s l o s e t h e i r s and d i e . The r e q u i r e m e n t s of s u r v i v i n g t r e e s f o r p h o t o s y n t h a t e may i n c r e a s e more r a p i d l y t h a n t h e i r c a n o p y c a n s u s t a i n b e c a u s e t h e volume of l i v i n g c e l l s i n c o n d u c t i n g sapwood a n d a s s o c i a t e d t i s s u e s c o n t i n u e s t o i n c r e a s e a s a t r e e grows i n h e i g h t . The m a i n t e n a n c e c o s t of t h e s e a d d i t i o n a l l i v i n g c e l l s c a u s e s a d r a i n on r e s e r v e s and f u r t h e r r e d u c e s s t e m wood p r o d u c t i o n p e r u n i t of f o l i a g e . The r e d u c t i o n i n g r o w t h r a t e s i s p a r t i c u l a r l y r a p i d i n warm e n v i r o n ments b e c a u s e r e s p i r a t i o n i n c r e a s e s e x p o n e n t i a l l y w i t h temperature (ref. 4 ) . D e p a r t u r e s f r o m t y p i c a l l y o b s e r v e d b o l e t a p e r and o t h e r g r o w t h a b n o r m a l i t i e s may b e u s e f u l a s a d d i t i o n a l i n d i c a t o r s of

stress ( r e f . 1 2 , r e f . 1 3 ) . With some i d e a o f what i s n o r m a l , w e may now l o o k a t s t r u c t u r a l and o t h e r p h y s i o l o g i c a l c h a r a c t e r i s -

t i c s a s s o c i a t e d w i t h d y i n g trees i n d i f f e r i n g e n v i r o n m e n t s . DROUGHT-INDUCED DEATH

P e r i o d s of e x t e n d e d d r o u g h t a r e n o t p a r t i c u l a r l y h a r m f u l i f

trees h a v e w e l l d e v e l o p e d r o o t s y s t e m s and c a n o p i e s a r e adeq u a t e l y e x p o s e d t o p h o t o s y n t h e s i z e when c o n d i t i o n s a r e s u i t a b l e . Thus s a v a n a t y p e f o r e s t s r a r e l y d i e f r o m d r o u g h t ( r e f . 1 4 ) . A s l i g h t d r o u g h t t h a t d o e s n o t c o m p l e t e l y h a l t p h o t o s y n t h e s i s may a c t u a l l y i n c r e a s e c a r b o h y d r a t e r e s e r v e s a n d t h e l e v e l s of d e f e n s i v e compounds b e c a u s e demands f o r s h o o t g r o w t h a r e i m m e d i a t e l y reduced.

S u s t a i n e d d r o u g h t , however, h a l t s p h o t o s y n t h e s i s ,

d e p l e t e s r e s e r v e s a n d d e f e n s i v e compounds, and e v e n t u a l l y r e d u c e s t h e amount of canopy ( r e f . 1 5 , r e f .

16).

I t i s s h a l l o w l y r o o t e d trees g r o w i n g i n d e n s e s t a n d s t h a t

120 a r e u s u a l l y most s u s c e p t i b l e t o d r o u g h t ( r e f . 1 4 , r e f .

17). Thus

i n t h e b o r e a l s p r u c e f o r e s t s o f Norway, o l d , s h a l l o w l y r o o t e d

t r e e s , g r o w i n g w i t h c l o s e d c a n o p i e s s u f f e r e d most from b a r k b e e t l e s f o l l o w i n g a s e r i e s of d r o u g h t y y e a r s ( r e f . 1 8 ) . I f t h e d e n s i t y of t r e e s i n s p r u c e s t a n d s i s r e d u c e d , more l i g h t a n d more w a t e r a r e a v a i l a b l e t o s u r v i v o r s . Trees p r o v i d e d w i t h s u c h a n improved e n v i r o n m e n t showed h i g h e r s t e m wood g r o w t h r a t e s a n d c o u l d b e t t e r r e s i s t a l e t h a l f u n g u s c a r r i e d by b a r k b e e t l e s ( r e f . 1 9 ) . Trees w i t h more e x p o s e d c a n o p i e s had a l a r g e r s u r p l u s of p h o t o s y n t h a t e t o c o n t r i b u t e t o d e f e n s e r e a c t i o n s (ref. 20). DEATH BY MECHANICAL ABRASION

Trees l o c a t e d on a s e a c o a s t , a l o n g g o r g e s , o r on h i g h

r i d g e s a r e o f t e n b u f f e t e d by h i g h w i n d s . U s u a l l y t r e e s growing i n s u c h a r e a s h a v e a t a i l o r e d canopy s h a p e d by t h e p r e v a i l i n g wind. They a r e s h o r t i n s t a t u r e and e x h i b i t s t r o n g b o l e t a p e r . I n c a s e s where h e a v y snows o r i c e a c c u m u l a t e , t h e c o m b i n a t i o n of m e c h a n i c a l f o r c e s may t h r e a t e n s u r v i v a l a s t r e e s grow i n h e i g h t and a r e s u b j e c t e d t o i n c r e a s i n g damage. I n d e n s e f o r e s t s of b a l s a m f i r ( A b i e s b a l s a m e a ) i n t h e White M o u n t a i n s o f N e w Hamsphire ( U S A ) ,

s y n c h r o n o u s d e a t h of t r e e s

p e r i o d i c a l l y o c c u r ( r e f . 2 1 ) . The s u b a l p i n e e n v i r o n m e n t i s h a r s h , a n d t h e d e n s i t y of t r e e s s u c h t h a t wood p r o d u c t i o n p e r u n i t of f o l i a g e i s c o n s i s t e n t l y low t h r o u g h o u t t h e s e q u e n c e from young t o o l d e r f o r e s t s ( r e f . 2 2 ) . A s t h e s e f o r e s t s grow, a i r t u r b u l e n c e i n t h e canopy i n c r e a s e s , f a v o r i n g t h e a c c u m u l a t i o n s of r i m e i c e a n d s h e a r i n g of f o l i a g e d u r i n g w i n t e r s t o r m s ( r e f . 22, r e f .

2 3 ) . A s a r e s u l t , a n i n c r e a s i n g p r o p o r t i o n of new

f o l i a g e i s removed f r o m c a n o p i e s a s s t a n d d e v e l o p m e n t p r o c e e d s t o w a r d s d i e b a c k and d e a t h ( r e f . 2 4 ) . F o l l o w i n g a n e x p e r i m e n t where t r e e s were a r t i f i c i a l l y exposed t o i n c r e a s i n g t u r b u l e n c e by s e l e c t i v e l y removing a d j a c e n t

t r e e s , a s u b s t a n t i a l d e c l i n e i n f o l i a g e mass and p r e - b u d b r e a k f o l i a g e s t a r c h c o n t e n t was o b s e r v e d o v e r a two y e a r p e r i o d ( r e f . 23). Increased exposure a l s o r e s u l t e d i n a dramatic increase i n r o o t damage r e l a t i v e t o c o n t r o l t r e e s . B r e a k a g e o f r o o t s a s s o c i a t e d w i t h e x t r e m e movement of t r e e b o l e s w a s f o l l o w e d by s e c o n d a r y i n f e c t i o n o f r o o t s , f u r t h e r w e a k e n i n g trees t o mechan-

121

ical stress. Loss of active foliage and roots was accompanied by a 2-to 5-fold reduction in annual wood increment among dieback zone trees (ref.23 , ref. 24 )

.

DEATH THROUGH NUTRIENT DEFICIENCIES OR IMBALANCES There are situations where nutrients are so limiting that once a forest has developed, demand for nutrients are more than what is returned through normal litterfall, root turnover, and decomposition. At other times, young or very old soils are sufficiently impoverished in some essential nutrient that existing trees are prone to repeated attack from insects or diseases. A case in point is a subalpine forest in the Pacific Northwest (U.S.A.) that grows on nitrogen deficient soils developed on volcanic ash deposited within the last 7000 years. These forests, dominated by

mountain hemlock (Tsuqa merten-

siana), die periodically from infection of a root rot (ref.25). After large trees die, younger ones are reestablished and continue to grow without major damage from root rot until the forest canopy reaches maximum development; then rates of decomposition and wood production per unit of foliage again slow and the cycle is repeated (ref.26). Fertilizing at only 50 kg N per ha per year increased the nitrogen content of foliage, and presumedly also the photosynthetic activity (ref.27). Wood production per unit of foliage by small trees situated in gaps, or in the open, also increased over that of unfertilized samplings (R.H. Waring, unpublished). In controlled environment studies, Matson and Waring (ref.28) demonstrated that starch reserves, total nitrogen, and amino acids were significantly increased when mountain hemlock seedlings were provided with sufficient light and nutrients. Susceptibility to root rot was reduced. On the other hand, fertilization in the absence of increasing light caused trees to become more susceptible to root rot, probably because protein synthesis and maintenance require large amounts of photosynthate that might otherwise go toward defense against the pathogen. An excess of essential nutrients may also cause relative defiiencies in other minerals, particularly if growth rates are increased (ref.29, ref.30). Entry et al. (ref.31) demonstrated in an experiment with western white pine seedlings (Pinus monti-

122

c o l a ) t h a t i m b a l a n c e d n u t r i t i o n i n c r e a s e d s u s c e p t i b i l i t y of p l a n t s t o i n j u r y by A m e l l a r i a r o o t r o t . I m b a l a n c e d n u t r i t i o n h a s been r e p o r t e d i n c o n i f e r s a l o n g a i r p o l l u t a n t g r a d i e n t s i n C a l i f o r n i a ( r e f . 3 2 ) and i n t h e N e w Engl a n d S t a t e s ( r e f . 3 3 ) , and i n a s s o c i a t i o n w i t h n i t r o g e n - f i x i n g d e c i d u o u s t r e e s ( r e f . 1 2 ) . Whether t h e s e s i t u a t i o n s a r e c o n t r i b u t i n g t o f o r e s t d e c l i n e a s s o c i a t e d w i t h a t t a c k by p a t h o g e n s i s n o t known b u t symptoms s u c h a s g r e e n - l e a f

f a l l , abnormal b o l e

growth, and r e d u c e d r o o t p r o d u c t i o n a r e h i g h l y s u g g e s t i v e ( r e f . 13)

.

SUMMARY Trees e x p e r i e n c i n g a b n o r m a l s t r e s s g e n e r a l l y e x h i b i t a

v a r i e t y o f b i o c h e m i c a l and s t r u c t u r a l r e s p o n s e s t h a t may h e l p u s i n d i a g n o s i n g t h e k i n d of s t r e s s and t h e p r o b a b i l i t y of t r e e s u r v i v a l . Many t y p e s of stresses r e d u c e t h e canopy and i t s p h o t o s y n t h e t i c a c t i v i t y . D r o u g h t , m e c h a n c i a l a b r a s i o n , and n u t r i e n t i m b a l a n c e s c a u s e d i s t i n c t i v e a l t e r a t i o n s i n how p h o t o s y n t h a t e i s a l l o c a t e d a l o n g t h e b o l e and t o t h e r o o t s .

To amer-

l i o r a t e d i f f e r e n t k i n d s of stress, d i f f e r e n t t r e a t m e n t s a r e required.

Success should r e s u l t i n r e e s t a b l i s h i n g a m o r e t y p i c a l

p a t t e r n i n which p h o t o s y n t h a t e i s d i s t r i b u t e d w i t h i n a t r e e . ACKNOWLEDGMENTS T h i s p a p e r i s c o n d e n s e d from of o n e p r e p a r e d f o r a c u r r e n t i s s u e of B i o S c i e n c e c o n c e r n e d w i t h t h e c a u s e s of t r e e d e a t h and r o l e of d e a d t r e e s i n f o r e s t e c o s y s t e m s . RE FERENCES

1 R . H . W h i t t a k e r a n d G . M . Woodwell, J . E c o 1 . , 5 6 ( 1 9 6 8 ) 1-25. 2 R.H. Waring, Adv. E c o l . R e s . , l 3 ( 1 9 8 3 ) 327-354. 3 H . A . Mooney a n d C . Chu, O e c o l o g i a 1 4 ( 1 9 7 4 ) 295-306. 4 R.H. Waring a n d W.H. S c h l e s i n g e r , F o r e s t e c o s y s t e m s : c o n c e p t s a n d management, Academic P r e s s I n c . , O r l a n d o , F l a . , 1 9 8 5 , Ch. 4 , p.7. 5 R.G. McMinn, Can. J . B o t . , l l ( 1 9 6 3 ) 105-122. 6 R . H . Waring a n d B.D. C l e a r y , S c i . , 2 0 4 ( 1 9 6 7 ) 1380-1386. 7 P.M. Wargo, P h y t o p a t h . , 6 2 ( 1 9 7 2 ) 1278-1283. 8 W.L. Webb, F o r . S c i . , 2 7 ( 1 9 8 1 ) 224-232. 9 S . L i n d e r a n d B. A x e l s s o n , i n R.H. Waring ( E d . ) , P r o c . IUFRO Workshop, Carbon u p t a k e a n d a l 1 o c a t i o n : k e y t o management of s u b a l p i n e f o r e s t e c o s y s t e m s , C o r v a l l i s , O R . , Aug. 2-3, 1982, F o r . R e s . Lab., Oregon S t a t e Univ., 1982.p.38-44. Corvallis, O R . , U.S.A.

123

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

33

M.R. Keyes and C.C. Grier, Can. J. For. Res.,ll (1981) 599-605. R.H. Waring and G.B. Pitman, Eco1.,66 (1985) 889-897. R.H. Waring,. For. Ecol.and Manage.,l2 (1985) 93-112. P. Schutt and E.B. Cowling, Plant Disease,69 (1985) 548-558. J.R. Griffin, Eco1.,54 (1973) 152-159. J. Landsberg, and F.R. Wylie, Austr. J. Bot.,27 (1983) 597-596. E.W. Pook, Aust. J. Bot.,32 (1984) 405-413. C.L. Wambolt, Can. J. Bot.,51 (1973) 2333-2337. R. Worrell, Medd. Nor. inst. skogforsk.,38 (1983) 1-34. E. Christiansen, Eur. J. For. Path.,l5 (1985) 160-167. E. Christiansen, and A. Ericsson, Can. J. For. Res.,l6 (1986) 78-83. D.G. Sprugel, J. of Eco1.,64 (1976) 889-910. P.J. Marchand, Can. J. For. Res.,l4 (1984) 51-56. P.J. Marchand, F.L. Goulet, and T.C. Harrington, Can. J. For. Res., (1986), in press. J.R. Foster, J. Ecol., (1986), submitted for publication. K.J. McCauley and S.A. Cook, For. Sci.,25 (1980) 23-29. R.H. Waring, K. Cromack, Jr., P.A. Matson, R.D. Boone, and S.G. Stafford, For. Ecol. and Manage.,(1986), submitted for publication. F.S. Chapin, , 111, A.J. Bloom, C.B. Field, and R.H. Waring, BioSci., (1986), in press. P.A. Matson and R.H. Waring, Eco1.,65 (1984) 1517-1524. T. Ingestad, Physiol. Plant.,45 (1979) 149-157. T. Ingestad, Physiol. Plant.,45 (1979) 373-380. J.E. Entry, N.E. Martin, and K. Cromack, Jr., For. Ecol. and Manage.,l4 (1986),in press. P.J. Zinke, U . S . For. Serv. Pacific Southwest Forest and Range Exper. Sta., Gen. Tech. Report,43 (1980) 88-99. J.R. Foster, Water, Air, and Soil Pollution, (1986), submitted for publication.

T. Schneider (Editor)/Acidificationand its Policy Implications

125

0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

STRESS FACTORS:

H.C.

TRENDS AND RECOVERY

MARTIN and T.G.

BRYDGES

Atmospheric Environment Service, Environment Canada, 4905 D u f f e r i n S t r e e t , Downsview, Ontario, M3H 5T4, (Canada)

ABSTRACT Studies o f environmental damage f r o m a c i d i f i c a t i o n by a c i d d e p o s i t i o n i n Canada d a t e from t h e 1950's. I n t h e l a t e 1960's, a c i d i f i c a t i o n o f surface waters and o t h e r forms o f environmental damage near p o i n t source emissions i n Canada and t h e U n i t e d States l e d t o development o f Clean A i r Acts i n b o t h c o u n t r i e s and t h e implementation o f v a r i o u s c o n t r o l programs. Sulphur d i o x i d e emissions reached a l l - t i m e highs around 1970 t o 1973 and SO2 emissions i n b o t h c o u n t r i e s decreased from t h a t t i m e u n t i l t h e e a r l y 1980's. U.S. emissions decreased from about 28 m i l l i o n tonnes t o 21 m i l l i o n tonnes from 1973 t o 1984 and Canadian emissions decreased from 6.6 t o 3.8 m i l l i o n tonnes i n t h e same t i m e period. Canadian emissions a r e ensured t o decrease f u r t h e r as a r e s u l t of Canada's Sulphur D i o x i d e Control Program which goes beyond t h e o b j e c t i v e s o f t h e 30% Club. The a q u a t i c environment has responded f a v o r a b l y t o these emission reductions. Sulphate r u n o f f from 12 Nova S c o t i a n and 8 Newfoundland watersheds decreased by n e a r l y 50% i n t h e corresponding time. Rivers i n b o t h cases showed an expected increase i n pH. Near Sudbury, Ontario, f o l l o w i n g r e d u c t i o n s i n emissions from t h e l a r g e smelters, s u r f a c e water s u l p h a t e c o n c e n t r a t i o n s have d e c l i n e d and pH of t h e a c i d i f i e d l a k e s has increased. The p a s t r e d u c t i o n s i n SO2 and f a v o r a b l e response i n t h e environment i s most encouraging b u t we a r e s t i l l faced w i t h a s i t u a t i o n o f extensive s u r f a c e water damage. Lakes i n l a r g e areas o f Eastern Canada have l e s s than 20% o f t h e a l k a l i n i t y expected from normal weathering processes and as many as 14,000 i n d i v i d u a l l a k e s have been a c i d i f i e d . There a r e examples o f t h e t o p meter o f s o i l water b e i n g a c i d i f i e d by a combination o f sulphate and nitrate. B i o l o g i c a l surveys have documented a c o n t i n u i n g d e c l i n e i n b i o l o g i c a l q u a l i t y o f l a k e s and have documented t h e l o s s o f a q u a t i c organisms as a r e s u l t o f p e r i o d i c pH depressions i n streams. I n r e c e n t years, we have observed d e c l i n e o f sugar maple, our n a t i o n a l emblem, i n C e n t r a l and Eastern Canada. The t r e e s have been subjected t o a t t a c k s by t e n t c a t e r p i l l a r and severe weather c o n d i t i o n s . There i s i n c r e a s i n g evidence t h a t t h e d e c l i n e i s caused by a complex i n t e r a c t i o n o f i n s e c t damage, weather and s t r e s s caused by a c i d i c p r e c i p i t a t i o n .

126 We can conclude f r o m t h e e a s t e r n N o r t h American experience t h a t w h i l e emissions and d e p o s i t i o n have been reduced and water q u a l i t y has improved, b o t h t h e a q u a t i c and f o r e s t s i t u a t i o n s a r e s t i l l f a r from acceptable.

INTRODUCTION Over t h e p a s t few decades, research s c i e n t i s t s throughout t h e w o r l d have been p r o v i d i n g documentation of t h e impacts o f " a c i d r a i n " on t h e n a t u r a l and human environment.

The thousands o f t e c h n i c a l r e p o r t s u n i f o r m l y present

a bleak p i c t u r e , d e p i c t i n g a wide-spread and pervasive d e t e r i o r a t i o n i n t h e h e a l t h o f t e r r e s t r i a l and a q u a t i c ecosystems, s o i l s , man-made s t r u c t u r e s and monuments, human health, and so on. I n Canada, primary a t t e n t i o n has been d i r e c t e d towards surface waters and t h e i r remarkable d e t e r i o r a t i o n , over t h e l a s t few decades i n t h e eastern p a r t o f t h e country.

As a consequence o f t h e s c i e n t i f i c i n f o r m a t i o n

a v a i l a b l e , Canada i s now implementing a SO2 Control Program which w i l l reduce emissions by 50% i n e a s t e r n Canada by 1994. The s i t u a t i o n concerning f o r e s t ecosystems i s l e s s c l e a r . To date t h e r e i s no c o n c l u s i v e l i n k between t h e l o n g range t r a n s p o r t o f a i r p o l l u t i o n and observed r e g i o n a l f o r e s t decline.

However, a problem o f p a r t i c u l a r n o t e has

been observed i n maple stands i n t h e provinces o f Ontario, Quebec, and New Brunswick.

Although t h e d e c l i n e occurs i n some o f t h e areas most h e a v i l y

impacted by LRTAP, n a t u r a l stresses ( c l i m a t e and i n s e c t s , i n p a r t i c u l a r ) a r e c e r t a i n l y c o n t r i b u t i n g t o t h e observed d e t e r i o r a t i o n as w e l l . The purpose o f t h i s conference i s t o b r i n g t o g e t h e r s c i e n t i s t s and p o l i c y makers i n o r d e r t o c l a r i f y t h e s t a t e o f knowledge and address t h e p o l i c y t h a t may be r e q u i r e d by governments t o c o r r e c t unacceptable s i t u a t i o n s . T h i s paper presents some work on Canadian l a k e s and streams.

The

p r e l i m i n a r y r e s u l t s i n d i c a t e t h a t decreases i n SO2 emissions i n North America over t h e p a s t 10-15 y e a r s have been c o i n c i d e n t w i t h a marked improvement i n t h e q u a l i t y o f some o f t h e s u r f a c e waters. t h i s i n f o r m a t i o n t o p o l i c y makers i s evident.

The importance o f

I t appears t h a t r e d u c t i o n s i n

s u l p h u r d i o x i d e emissions can be l i n k e d t o improved s u r f a c e water q u a l i t y i n a t i m e frame which i s p r a c t i c a l i n terms o f implementing c o n t r o l programs over a decade o r so.

F u r t h e r improvement may be expected as t h e Canadian

Control Program becomes f u l l y implemented.

127 CHANGES I N SO2 EMISSIONS

I n North. America, SO2 emissions reached a t 1 t i m e highs between 1970 and As a r e s u l t o f b o t h Canada and t h e U.S.A. i n s t i t u t i n g Clean A i r Acts

1973.

and e n f o r c i n g more s t r i n g e n t standards f o r l o c a l a i r q u a l i t y , a l a r g e amount o f SO2 was removed from t h e stack gases.

Large increases i n energy c o s t s

a l s o encouraged energy c o n s e r v a t i o n and reduced f u e l consumption d u r i n g t h i s period. F i g u r e I, shows t h e t r e n d i n

SO2 emissions i n t h e U n i t e d States from

1900-1983 (Envi ronmental P r o t e c t i o n Agency, 1985 , 1986 1. d e c l i n e o f about 30% f r o m 1973 t o 1983.

There has been a

T h i s d e c l i n e i s a t t r i b u t e d to:

s t r i n g e n t new source performance standards; l o w e r sulphur c o n t e n t o f t h e c o a l consumed; and r e t r o f i t t i n g o f scrubbers ( N a t i o n a l Coal Association, 19861, among o t h e r t h i n g s . P r o j e c t i o n s f o r t h e n e x t decade f o r U.S.

u t i l i t i e s vary from a c o n t i n u i n g

d e c l i n e p r e d i c t e d by t h e N a t i o n a l Coal Association, 1986, t o increases o f as much as 5 m i l l i o n tons unless f u r t h e r c o n t r o l measures a r e i n t r o d u c e d (ICF, 1986). I n Eastern Canada, SO2 emissions d e c l i n e d by about 50% d u r i n g t h e 1970s and e a r l y 1980s, F i g u r e 2.

Although t h i s d e c l i n e can be a t t r i b u t e d p a r t l y

t o reduced economic a c t i v i t y i n t h e l a s t few years, i t has been l a r g e l y due t o SO2 emission c o n t r o l s t o improve a i r q u a l i t y near t h e l a r g e non-ferrous smelters i n Sudbury. Ltd.,

I n a d d i t i o n , one o f t h e smelters a t Sudbury, INCO

and t h e thermal power p l a n t s o f O n t a r i o Hydro a r e now o p e r a t i n g under

s p e c i a l r e g u l a t i o n s i n t r o d u c e d t o c o n t r o l t h e l o n g range t r a n s p o r t o f S02. These r e g u l a t i o n s a r e over and above t h e c o n t r o l s needed t o improve l o c a l a i r quality.

A f u r t h e r r e d u c t i o n i n Canadian emissions has been assured by t h e f e d e r a l / p r o v i n c i a l agreements i n Canada c a l l i n g f o r a 50% r e d u c t i o n i n e a s t e r n Canadian SOpemissions by 1994.

Both Canada and t h e U n i t e d States

s t i l l have a l o n g way t o go i n technology development and technology implementation t o achieve t h e r e q u i r e d r e d u c t i o n s i n t h e mid-1990's b u t we a r e c o n f i d e n t t h a t we w i l l achieve our o b j e c t i v e s o f r e d u c i n g d e p o s i t i o n t o acceptable Val ues.

SURFACE WATER CHANGES I N CANADA The d e c l i n e s i n SO2 emissions have caused a corresponding decrease i n d e p o s i t i o n i n Eastern N o r t h America.

Table 1 shows changes i n t h e sulphate

y i e l d s from watersheds i n Nova S c o t i a and Newfoundland (Thompson, 1986). From t h e e a r l y 1970's t o t h e e a r l y 1980's t h e sulphate e x p o r t from t h e watersheds measured i n t h e r u n o f f d e c l i n e d by n e a r l y 50%, r e f l e c t i n g t h e

128

decline i n emissions i n t h e areas upwind of the region. Atmospheric models have calculated an expected deposition reduction of 20-25%. These numbers a r e i n good agreement, considering the expected e r r o r i n model calculations and i n the measurements, and a r e most encouraging with regard t o demonstrating t h a t a reduction i n SO2 emissions leads t o reduction i n sulphate i n surface waters. Table 1 also shows the change i n the pH of the rivers i n t h e same time-frame, and indeed, there has been t h e expected decline in acidity. The water quality i s not y e t acceptable f o r a healthy biological community, b u t there have been improvements.

TABLE 1 Sulphur Dioxide Emission Changes, Sulphate Export from Nova Scotian ( 1 2 ) and Newfoundland (8) Watersheds, and pH Ranges from Associated Rivers

SO2 Emission i n Eastern Canada and the United States (yearly averages)

1971-1973

1982-1983

Change

27.0

20.3

-25%

Watershed Export ( k g s SOq/ha/yr) A Nova Scotia B Newfoundland

39 2 6.7 32 2 12

21 2 6.1 18 t 8

pH range of river* A Nova Scotia B Newfoundland

4.4 t o 6.5 5.5 t o 7.7

4.5 t o 6.7 6.1 t o 7.8

-47% -44%

* A l l r i v e r s decreased i n sulphate yield and increased i n pH.

Water quality has a l s o improved i n lakes i n the Sudbury area following the major SO2 emission reductions by the two l a r g e s t smelters, INCO Ltd. and Falconbridge Ltd. (70 and 75% reductions respectively) during the 1970's. By 1985, there had b e y about a 40% reduction i n s u l f a t e concentration i n one study lake, (Figure 3) ( D i l l o n , 1986) and a corresponding increase i n pH from 4.1 t o 4.6 (68% decrease i n hydrogen ion). Substantial increases i n pH were observed f o r a large number o f acidified lakes being monitored i n t h a t area i n an extensive survey (Figure 4) (Keller & Pitblado, 1985).

129 B i o l o g i c a l recovery has been observed i n two study l a k e s which have shown increased biomass of algae and increased d i v e r s i t y o f b o t h algae and zooplankton (Havas, 1986). Hutchinson & Havas (1986) have a l s o r e p o r t e d recovery o f two study l a k e s near Sudbury.

T h e i r study i n c l u d e d d e p o s i t i o n and l a k e chemistry data from

b e f o r e t h e c o n s t r u c t i o n o f t h e t a l l stack by I n c o and b e f o r e l a r g e - s c a l e emission r e d u c t i o n s began a t t h e smelters.

Sulphate d e c l i n e d by 50% and t h e

pH increased from approximately 4.1 t o 5.8 i n t h e most a f f e c t e d l a k e w h i l e b u l k d e p o s i t i o n o f s u l p h a t e measured d u r i n g t h e summer decreased by 75% between 1970 and 1977. Our m o d e l l i n g c a l c u l a t i o n s p r e d i c t t h a t o t h e r areas i n eastern North America have probably experienced some improvement i n surface water qua1 i t y as a r e s u l t o f t h e emission reductions.

However, t h e r e s u l t f r o m o u r Nova

S c o t i a and Newfoundland r i v e r s along w i t h t h e Sudbury r e s u l t s f u l l y s u b s t a n t i a t e t h e p o s i t i o n t h a t Canada has taken, t h a t i s , reducing SO2 emissions w i l l l e a d t o d e c l i n e i n a c i d i t y o f s u r f a c e waters. The r e c e n t U.S.

N a t i o n a l Academy o f Science (1986) r e p o r t on trends

i n d i c a t e s decreasing c o n c e n t r a t i o n s o f sulphate i n r i v e r s in t h e n o r t h e a s t e r n U n i t e d States.

These f i n d i n g s a r e a f u r t h e r c o n f i r m a t i o n o f

t h e changes t h a t a r e observed i n t h e A t l a n t i c Provinces o f Canada.

CURRENT STATUS OF SURFACE WATERS I N EASTERN CANADA Chemistry While t h e obvious successes o f p a s t SO2 r e d u c t i o n programs a r e encouraging, we must be aware o f t h e f a c t t h a t t h e p r e s e n t sulphate d e p o s i t i o n i s t o o h i g h and p r e s e n t water q u a l i t y i s n o t acceptable. F i g u r e 5, ( J e f f r i e s , 1986) shows t h e s t a t u s o f surface waters as measured by t h e r a t i o o f a l k a l i n i t y t o calcium (Ca) p l u s magnesium (Mg). There a r e many mechanisms used t o e x p l a i n t h e surface water a c i d i f i c a t i o n problem b u t r e g a r d l e s s o f which mechanisms a r e causing a c i d i f i c a t i o n t o occur, t h e r a t i o o f a l k a l i n i t y t o c a l c i u m p l u s magnesium has been reduced, e i t h e r by decreases i n a l k a l i n i t y ,

increases i n Ca and Mg o r both.

weathering processes, t h e r a t i o w i l l be u n i t y .

Under normal

I f t h e r a t i o becomes zero,

then a l k a l i n i t y has been exhausted and we r e g a r d t h e l a k e t o have been acidified.

A c i d i f i e d l a k e s a r e devoid of fl’sh and have reached an end-point

w i t h regards t o b i o l o g i c a l damage.

However, l a k e s which s t i l l r e t a i n some

a l k a l i n i t y , n e v e r t h e l e s s s u f f e r b i o l o g i c a l damage. about 8,000 sample p o i n t s .

The map i s based on

130

Large areas of Ontario and Quebec f a l l w i t h i n the 0.2 contour f o r the ratio. T h i s means t h a t the surface waters have l e s s than 20% of the a l k a l i n i t y which we would expect from normal weathering processes. Surface waters in Nova Scotia have been severely affected w i t h a r a t i o of zero being common and much of Newfoundland has also been damaged. W i t h i n the most affected areas, some waters have been acidified. Our l a t e s t projection i s t h a t as many as 14,000 lakes have been acidified. I t i s our goal t o see these r a t i o s increase and eventually a r r i v e back a t the natural value of close t o unity. The cause of the low a l k a l i n i t y values can be seen i n Figure 6. The values of the r a t i o of sulphate t o calcium plus magnesium mirrors the a l k a l i n i t y r a t i o s i n F i g u r e 5. As the a l k a l i n i t y declines, i t is replaced by sulphate. The areas of lowest a l k a l i n i t y / (Ca plus Mg) r a t i o s are also the areas of highest sulphate deposition. New findings on ground water quality are of considerable concern t o us. A t one of our study s i t e s near Sault Ste. Marie, Ontario, soil waters, down t o about one meter have been acidified w i t h a complete loss of alkalinity a t times. T h e l o s t a l k a l i n i t y has been largely replaced by sulfate. D u r i n g the most extreme conditions, n i t r a t e contributes t o the a l k a l i n i t y loss as well. The depth of acidic ground water extends t o below the depth of the root zone of the f o r e s t cover. Figure 7 shows the chemical composition of the water d u r i n g periods of heavy rain and spring runoff when the ground water becomes f u l l y acidified (Johnston, 1986). In March, the ground water was influenced by a heavy s p r i n g rain with low pH. Subsequently, alkalinity recovered s l i g h t l y until the onset of s p r i n g melt i n mid-April, when the a l k a l i n i t y again f e l l t o zero. B i ol ogy The current water chemistry i n many of our lakes i s detrimental t o biological l i f e even though some a l k a l i n i t y remains. Rooke and Mackie (19841, have recorded the recent collapse of a mollusc species i n a lake under study i n central Canada. T h i s i s an important observation because i t confirms t h a t the biological quality of the lake i s deteriorating w i t h time. Another recent report of biological damage i s based on extensive baseline data collected over forty years ago i n Algonquin Provincial Park i n Ontario. Acid s e n s i t i v e species of stream invertebrates have been eliminated. T h i s has been caused by repeated short term pH depressions i n the stream rather than by long term a c i d i f i c a t i o n (Hall, 1986). T h i s important observation demonstrates the loss of biological quality under chemical s t r e s s conditions.

131 Sugar Maple Decline Over t h e p a s t few years t h e r e have been r e p o r t s o f decline i n sugar maples (Acer saccharm) i n t h e provinces o f Ontario, Quebec and New Brunswick.

A number o f maple syrup producers have gone o u t o f business and

o t h e r farmers a r e concerned f o r t h e f u t u r e o f t h e i r trees. P r e l i m i n a r y i n v e s t i g a t i o n s have n o t shown any obvious disease o r i n s e c t - r e l a t e d causes f o r t h e decline.

Some o f t h e areas a f f e c t e d have been

subjected t o f o r e s t t e n t c a t e r p i l l a r a t t a c k s and severe weather conditions have occurred s i n c e 1980.

However, one d e t a i l e d study (Mclaughlin, 1985)

has found t h a t t h e t r e e s c u r r e n t l y s u f f e r i n g d e c l i n e have decreased i n growth over t h e p a s t f o u r decades and t h e e f f e c t s o f a c i d i c p r e c i p i t a t i o n have been i n c l u d e d i n t h e s t r e s s f a c t o r s causing t h e decline. Environmental M o n i t o r i n g Canada recognizes t h e fundamental need t o have programs i n place which w i l l measure t h e environmental response r e s u l t i n g from t h e a c t i v i t i e s o f t h e

members o f t h e 30% Club. Consequently we s t r o n g l y support t h e work group i n i t i a t i v e t o e s t a b l i s h an i n t e r n a t i o n a l m o n i t o r i n g program and we commend Norway f o r t a k i n g t h e l e a d t o e s t a b l i s h t h e data bank f o r an i n t e r n a t i o n a l surface water m o n i t o r i n g program.

CONCLUSIONS We have observed reduced a c i d i f i c a t i o n o f surface waters as a r e s u l t o f Chemical and b i o l o g i c a l q u a l i t y o f surface

SO2 emission reductions.

waters have improved i n study lakes. However, i n h e a v i l y impacted areas, t h e c u r r e n t d e p o s i t i o n o f sulphate i s t o o h i g h and t h e b i o l o g i c a l q u a l i t y o f some surface waters j s s t i l l deteriorating. Surface waters i n extensive areas o f eastern Canada a r e badly damaged w i t h a l k a l i n i t y values o f l e s s than 20% o f t h e expected n a t u r a l value. Sulphate has been shown as t h e cause o f t h e l o s t a l k a l i n i t y . A c i d i f i c a t i o n o f ground water by a c i d d e p o s i t i o n has been found and i s o f Both

p a r t i c u l a r concern t o Canada w i t h regard t o t h e h e a l t h o f our forests.

s u l phate and n i t r a t e c o n t r i b u t e t o t h i s a c i d i f i c a t i o n . A d e c l i n e o f sugar maples across Eastern Canada has n o t been explained b u t p r e l i m i n a r y s t u d i e s i n d i c a t e t h a t " a c i d r a i n " i s one o f t h e s t r e s s f a c t o r s invol ved i n t h e problem. The s c i e n t i f i c b a s i s f o r t h e sulphur d i o x i d e c o n t r o l p o l i c i e s o f t h e 30% Club have been f u l l y supported by f i e l d observations.

132 REFERENCES D i l l o n , P.J., R.A. Reid and R. Girard, 1986. Changes i n t h e Chemistry o f Lakes F o l l o w i n g Reductions o f SO2 Emissions, Water, A i r and S o i l P o l l u t i o n ( i n press). Environmental P r o t e c t i o n Agency, 1985, r e p o r t #EPA 600/7-85-0099. Environmental P r o t e c t i o n Agency, 1986, r e p o r t #EPA 450/4-86-014. H a l l , R. , 1986. O n t a r i o M i n i s t r y o f t h e Environment, Dorset, Ontario, Canada, personal communication. Havas, M. , 1986. I n s t i t u t e f o r Environmental Studies, U n i v e r s i t y o f Toronto, Toronto, D n t a r i 0, Canada, personal communication. Hutchinson, Thomas C. and Magda Havas, 1986. Recovery o f p r e v i o u s l y a c i d i f i e d l a k e s near Coniston, Canada, f o l l o w i n g r e d u c t i o n s i n atmospheric s u l p h u r and metal deposition. Water, A i r & S o i l P o l l u t i o n 28, 319-333. ICF Incorporated, 1986. A n a l y s i s o f 6 and 8 m i l l i o n t o n and 30 year/NSPS and 30 y e a r 1.2 l b s u l f u r d i o x i d e emissions r e d u c t i o n cases. Report prepared f o r t h e U.S.A. Environmental P r o t e c t i o n Agency by ICF, Washington, D.C., U.S.A. J e f f r i e s , D., 1986. I o n i c r a t i o s i n s u r f a c e waters i n e a s t e r n Canada. Report t o t h e Economic Commission f o r Europe. E f f e c t s o f sulphur i n t h e environment, Work Group, Geneva, Switzerland. Johnston, L. 1986. N a t i o n a l Hydrology Research I n s t i t u t e , Saskatoon, Saskatchewan, personal communication. K e l l e r , W. and J. Roger P i t t b l a d o , 1985. Water Q u a l i t y Changes i n Sudbury Area Lakes, 1974-76 t o 1981-83, A c i d P r e c i p i t a t i o n i n O n t a r i o Study r e p o r t #007/85, O n t a r i o M i n i s t r y o f t h e Environment, Toronto, Ontario, Canada. McLaughlin, D.L. and S.N. Linzon, D.E. D i m a and W.D. McIlveen, 1985. Sugar maple d e c l i n e i n Ontario. O n t a r i o M i n i s t r y o f t h e Environment, A c i d P r e c i p i t a t i o n Study r e p o r t #026/85. N a t i o n a l Academy o f Sciences, 1986. A c i d Deposition, Long Term Trends, N a t i o n a l Academy Press, Washington, D.C., U.S.A. N a t i o n a l Coal Association, 1986. The Downward Trend i n Sulphur D i o x i d e Emissions a t Coal-Fired E l e c t r i c U t i l i t i e s . Washington, D.C., U.S.A. Rooke, J.B. and G.L. Mackie, 1984. Growth and p r o d u c t i o n o f t h r e e species o f molluscs i n s i x l o w a l k a l i n i t y fakes i n Ontario, Canada. Can. J. ZOO^. 62, 1474-1478. Thompson, Mary E., 1986. Chemical Trends i n Coastal R i v e r s i n Eastern Canada. NWRI, B u r l i n g t o n , Ontario, Canada ( i n press).

0

isoo

I

1910

I

1920

I

1930

1

1940

I

1950

1960

1970

1980

YEAR

Fig. 1

S u l p h u r dioxide emissions in United States f r o m 1900

-

1983

c.. W

W

c

8000 .

w

SO2 EMISSION TRENDS

- EASTERN CANADA

r

6000

4000

2000

0

1955

1965

1970

1972

1974

1976

YEAR

Fig. 2

S u l p h u r d i o x i d e emissions i n Canada from 1955

-

1983

1978

1980 1981 19821983

P

0 0

0 0 I

N

0 I

ea

0 I

P

0 0 I

v)

0

I

z 0

135

0

L m

.r

S

c,

0 a,

m

Y

L

A

aJ + m

z

m

aJ

7

L

V

In

0 'c

a, 3

>

m

7

a

I

m

E

-0

rcI

a, c,

a

-c

v)

3

7

S

v)

.r

-0 S W L t-

m m .C

LL

EXTENSIVE SURVEY OF LAKES NEAR SUDBURY ONTARIO

8.0

c3

7 7

. .

Q) 7

5 W

(3

a

.

.

7.0

Qo

/-

6.0

U W

2 5.0 NUMBERS REFER TO MULTIPLE DATA POINTS

4.0 4.0

6.0

5.0

AVERAGE pH 1974-76 Fig. 4

Changes i n t h e d i s t r i b u t i o n o f average pH o f l a k e s i n t h e Sudbury 1976 and 1981 1983 area between t h e periods 1974

-

-

7.0

8.0

Alk/Ca* + Mg* (equivalent basis)

Fig. 5

The s t a t u s o f s u r f a c e waters i n e a s t e r n Canada as measured by t h e r a t i o o f a l k a l i n i t y t o c a l c i u m p l u s magnesium. T h i s map i s based on a p p r o x i m a t e l y 8,000 sample p o i n t s

Fig. 6

E s t i m a t e s f o r t h e r a t i o o f s u l p h a t e t o c a l c i u m p l u s magnesium for t h e same l a k e s documented i n F i g . 5

GROUND WATER ANALYSIS AT 0.67m DEPTH AT TURKEY LAKE SAMPLE STATION

200

-

-

180 -

5.47

4.63

5.07

4.79

4.73

5.50

MARCH 8

MARCH 27

APRIL 10

APRIL 15

APRIL 19

JUNE 5

160 140

Q)

7

120

100 80 60

40

20 0

1985

Fig. 7

The chemical composition of s o i l water during periods o f heavy rain (March) and spring runoff (mid-April) f o r a watershed near S a u l t Ste. Marie, Ontario

-

141

T. Schneider (Editor)/Acidification and its Policj Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

ATMOSPHERIC A C I D DEPOSITION: EFFECTS ON THE CHEMISTRY OF FOREST SOILS

N.

van BREEMEN and J. MULDER

Dept.

of S o i l Science ti Geology, Agric. Univ.,

Box 37, 6700 AA

P.O.

WAGENINGEN

(The N e t h e r l a n d s )

ABSTRACT Enhanced a c i d i f i c a t i o n of s u r f a c e h o r i z o n s of f o r e s t s o i l s t a k e s p l a c e i n w i t h h i g h i n p u t s of a c i d a t m o s p h e r i c d e p o s i t i o n . The e v i d e n c e f o r enhanced s o i l a c i d i f i c a t i o n comes from measurements of o l d and new s o i l samples, from chemical a n a l y s e s of s o i l s o l u t i o n s , form input-output budgets of s o i l s and w a t e r s h e d s , and from geochemical s t u d i e s on s o i l p r o f i l e s . These r e s u l t s are s u p p o r t e d by s i m u l a t i o n models of s o i l a c i d i f i c a t i o n . A s a r e s u l t of enhanced s o i l a c i d i f i c a t i o n , m i n e r a l a c i d i t y h a s l a r g e l y r e p l a c e d o r g a n i c a c i d i t y as the dominant a c i d s o u r c e i n f o r e s t s o i l s . Many f o r e s t s o i l s are now c h a r a c t e r i z e d by lower pH v a l u e s , h i g h e r l e v e l s of d i s s o l v e d and adsorbed aluminum and lower l e v e l s of adsorbed base c a t i o n s t h a n t h e i r unpolluted counterparts. S a t u r a t i o n of ecosystems w i t h atmospheric n i t r o g e n from NO and NH3 i n c r e a s e s t h e r i s k of f u r t h e r s o i l a c i d i f i c a t i o n , p a r t i c u l a r l y i n s 5 t u a t i o n s of f o r e s t d e c l i n e . The h i g h e r l e v e l s of d i s s o l v e d aluminum, combined w i t h lower l e v e l s of base c a t i o n s , e s p e c i a l l y calcium, are p o t e n t i a l l y harmful f o r most p l a n t s . I n c r e a s e d s u p p l y of n i t r o g e n o n l y t e m p o r a r i l y i n c r e a s e s primary p r o d u c t i o n , but e v e n t u a l l y l e a d s t o f u r t h e r s o i l a c i d i f i c a t i o n , n u t r i e n t d i s o r d e r s and v e g e t a t i o n a l changes. While i t i s d i f f i c u l t t o prove o r d i s p r o v e t h e t h e s i s t h a t enhanced s o i l a c i d i f i c a t i o n p l a y s a major r o l e i n t h e p r e s e n t f o r e s t d e c l i n e , t h e r e c a n be l i t t l e doubt t h a t n e g a t i v e e f f e c t s occur, and are l i k e l y t o increase i n t h e f u t u r e u n l e s s d e p o s i t i o n rates are d r a s t i c a l l y decreased. L e v e l s of a t m o s p h e r i c d e p o s i t i o n t h a t are a c c e p t a b l e f o r terrestrial ecosystems i n t h e l o n g r u n v a r y , b u t are i n t h e o r d e r of 1 t o 1.4 e q u i v a l e n t kmol/ha.yr f o r s u l f u r and 0.4 kmol/ha.yr f o r n i t r o g e n . Current d e p o s i t i o n r a t e s i n many f o r e s t s i n c e n t r a l and w e s t e r n Europe are 2 t o 8 e q u i v a l e n t kmol/ha.yr f o r S and 1 t o 3 kmol/ha.yr f o r N.

areas

INTRODUCTION The q u e s t i o n whether a t m o s p h e r i c d e p o s i t i o n

soil

acidification

is

still

debated.

Some

significantly contributes

soil

scientists

consider

to

these

e f f e c t s small o r i n s i g n i f i c a n t : "Additions of a c i d i t y i n p r e c i p i t a t i o n t o s o i l s are i n s i g n i f i c a n t i n comparison with

the

amendmends.

acidity

...

produced

in

natural

processes

and

by

agricultural

soil

The i n f o r m a t i o n a v a i l a b l e t o t h i s t i m e i n d i c a t e s t h a t a c i d r a i n

142 has

not

adversely

affected

...

soils.

The

pronounced

intrinsic

buffering

c a p a c i t y p r o v i d e d by s o i l m i n e r a l s and o r g a n i c matter t e n d s t o minimize changes i n pH of

s o i l s receiving acid precipitation.

p r e c i p i t a t i o n are b e n e f i c i a l t o a g r i c u l t u r a l , (ref.

The amounts of N and S added by f o r e s t e d and unmanaged s o i l s " .

1).

I n t h i s a r t i c l e w e w i l l show t h a t t h e r e c a n be no r e a s o n a b l e doubt t h a t a n t h r o p o g e n i c a t m o s p h e r i c d e p o s i t i o n h a s s t r o n g l y enhanced s o i l a c i d i f i c a t i o n i n many f o r e s t areas i n Europe, normally found i n u n p o l l u t e d problems

and has c r e a t e d chemical s o i l c o n d i t i o n s not

soils.

W e w i l l call a t t e n t i o n t o the potential

a s s o c i a t e d w i t h high i n p u t s of a t m o s p h e r i c n i t r o g e n i n many f o r e s t Next w e w i l l

areas i n w e s t e r n Europe.

consider

t h e more d i f f i c u l t q u e s t i o n

whether t h e change i n chemical s o i l c o n d i t i o n s i s r e l a t e d t o t h e f o r e s t d e c l i n e reported

recently

i n western

Europe.

F i n a l l y we w i l l

briefly

d i s c u s s what

l e v e l s of a t m o s p h e r i c d e p o s i t i o n of s u l f u r and n i t r o g e n are a c c e p t a b l e i n t h e l o n g run. RATES OF SOIL ACIDIFICATION S o i l a c i d i c a t i o n i s d e f i n e d h e r e as a d e c r e a s e in t h e a c i d n e u t r a l i z i n g c a p a c i t y (ANC)

of s o i l m a t e r i a l t o a c e r t a i n depth (e.g.

of t h e r o o t z o n e ) below t h e s o i l s u r f a c e ( r e f s . often,

to t h e lower boundary

2 and 3 ) . A d e c r e a s e i n ANC i s

but not always, a s s o c i a t e d w i t h e c o l o g i c a l l y important changes i n s o i l

chemistry

such as

(1) a d e c r e a s e i n pH,

( 2 ) a d e c r e a s e i n t h e c o n t e n t s of

exchangeable b a s e s i n t h e s o i l , and ( 3 ) an i n c r e a s e i n t h e c o n c e n t r a t i o n s of p o t e n t i a l l y t o x i c metals (e.g.

aluminum) i n t h e s o i l s o l u t i o n .

We w i l l r e t u r n

t o t h e s e e c o l o g i c a l l y i m p o r t a n t s o i l changes l a t e r . Chemical i n p u t - o u t p u t

budgets f o r ecosystems and f o r a s s o c i a t e d s o i l s can be

transformed i n t o p r o t o n budgets, which show t h e magnitude of p r o t o n s o u r c e s and s i n k s a t t r i b u t a b l e t o v a r i o u s groups of p r o c e s s e s ( r e f s . 2 and 4 ) . By comparing proton f l u x e s a s s o c i a t e d with f o r m a t i o n i n t h e s o i l (e.g.

(2) internal acid

d i s s o c i a t i o n of o r g a n i c a c i d s and C 0 2 ) , ( 3 ) uptake

of c a t i o n s and a n i o n s by p l a n t s , o r g a n i c matter,

(1) atmospheric d e p o s i t i o n ,

( 4 ) m i n e r a l i z a t i o n of c a t i o n s and a n i o n s from

(5) m i n e r a l w e a t h e r i n g and i o n exchange r e a c t i o n s ,

d r a i n a g e e x p o r t of

dissolved a c i d i t y ,

and ( 6 )

t h e r e l a t i v e importance of atmospheric

d e p o s i t i o n t o t h e p r o t o n budget of a n ecosystem c a n be e v a l u a t e d . Table 1 g i v e s p r o t o n budgets f o r ecosystems w i t h a c i d i c and n e a r - n e u t r a l

soils,

and a t low

and h i g h l e v e l s of a t m o s p h e r i c a c i d d e p o s i t i o n . Rates of a c i d d e p o s i t i o n i n areas far from i m p o r t a n t p o l l u t i o n s o u r c e areas,

as i n I n d o n e s i a and Washington S t a t e , USA (ecosystems below 1 kmol of

k

p e r ha p e r year.

not s i g n i f i c a n t l y contribute t o s o i l a c i d i f i c a t i o n acid

soil

that

receives

high

loads

1 and

3 ) are g e n e r a l l y

I n such areas atmospheric d e p o s i t i o n does of

(AANC).

atmospheric

In t h e ( n a t u r a l l y )

acidity

(ecosystem

2),

143 TABLE 1 P r o t o n budgets of s e l e c t e d ecosystems. from van Breemen e t a1 ( r e f s . 5 and 6 ) .

P r o t o n t r a n s f e r s i n kmol/ha.yr.

sources atmosinternal p h e r i c C02 biomass+ sum input weathering Moderately a c i d s o i l , low a t m o s p h e r i c i n p u t 1. Agathis p l a n t a t i o n , 0.0 4.0 2.6 6.5 Indonesia Acidic s o i l , high atmospheric i n p u t 2. P i c e a forestsol4.8 0.0 2.3 7.1 l i n g , BRD N e u t r a l s o i l , low atmospheric i n p u t 3. Unvegetated t i l l Wash., 0.4 7.2 2.2 9.8 USA Calcareous s o i l under Quercus, moderate t o h i g h atmospheric i n p u t 4. Castricum, Neth. 2.2 12.4 0.2 15.0 5. Hackfort, Neth. 7.9 4.7 3.8 16.4

sinks

Ecosystem

however,

most of of

sum bio-

mass

weathering

6.5

3.0

3.5

0.0

-2.1

7.0

0.6

6.1

0.4

-5.9

9.9

0.0

9.9

0.0

-9.9

15.1

0.6

14.5

0.0

-14.3

16.3

0.2

16.1

0.0

-15.4

drainage output

AANC

t h e s o i l a c i d i f i c a t i o n i s c l e a r l y due t o atmospheric a c i d

deposition. In near-neutral dissociation

Taken

C02

can

s o i l s t h e r a t e of i n t e r n a l p r o t o n production due t o be

very

atmospheric a c i d i t y (ecosystems

high,

normally

exceeds

the

load

of

4).

However, i n c a l c a r e o u s s o i l s w i t h

e x c e s s i v e atmospheric d e p o s i t i o n (ecosystem

5 ) , C02 appears t o be r e p l a c e d by

strong

mineral

acids

3 and

and

(sulfuric

and

nitric

acid)

as

the

agent

of

soil

a c i d i f i c a t i o n , w h i l e t h e t o a l p r o t o n l o a d of t h e system remains about t h e same (compare

ecosystems

ecosystems ( r e f .

4 and

5).

Similar

findings

5). That r a t e s of present-day

were

reported

for

other

s o i l a c i d i f i c a t i o n i n areas with

high atmospheric d e p o s i t i o n a r e indeed h i g h e r t h a n during p r e - i n d u s t r i a l

times

a l s o f o l l o w s from t h e s t u d i e s of t h e change i n ANC w i t h d e p t h i n s o i l p r o f i l e s

of known age developed i n presumably homogenous p a r e n t m a t e r i a l .

By d i v i d i n g

t h e t o t a l amount of c a t i o n s , t h a t have a p p a r e n t l y disappeared over t h e depth of the s o i l p r o f i l e

by t h e age of t h e s o i l , one o b t a i n s t h e mean annual d e c r e a s e

i n ANC over t h e s o i l s ' l i f e time.

Over t h e p a s t t e n thousand y e a r s ,

pools of

base c a t i o n s p l u s A l have decreased a n n u a l l y by 0.1-0.5

( e q u i v a l e n t ) kmol/ha.yr

in

1.1-3.2

podzolic

soils

in

the

Netherlands

(ref.

7)

to

kmol/ha.yr

in

( m i n e r a l o g i c a l l y r i c h e r ) a c i d brown f o r e s t i n t h e FRG ( r e f . 8). The present-day

144 rates of

removal of Al p l u s b a s e c a t i o n s i n t h e same s o i l s under f o r e s t w i t h

rates of a t m o s p h e r i c d e p o s i t i o n i n t h e s e c o u n t r i e s are two t o

typical (high)

t e n times higher. EVIDENCE FOR DECREASED SOIL pH AND INCREASED LEVELS OF DISSOLVED ALUMINUM Whether

the

ecologically,

accelerated

e.g.

by

d i s s o l v e d aluminum, clean(er)

decrease

lowering

the

in

has

ANC

soil

pH

and

indeed

increasing

affected the

soils

levels

of

c a n only be decided by comparing a f f e c t e d ecosystems w i t h Reference d a t a may come from (1) ecosystems i n

r e f e r e n c e ecosystems.

less p o l l u t e d areas t h a t are v e r y similar t o t h e p o l l u t e d ecosystem, and ( 2 ) samples

or

analytical

data

a t m o s p h e r i c p o l l u t i o n (i.e. in

polluted

and

less

of

same s o i l a t a less advanced

the

by comparing "old"

polluted

areas

can

and r e c e n t samples).

never

be

completely

s t a g e of Ecosystems

comparable.

d i f f e r e n c e s i n s o i l chemical c o n d i t i o n s of similar ecosystems are

Nevertheless,

sometimes s o outspoken t h a t t h e r e c a n be l i t t l e doubt a b o u t t h e e f f e c t s of a c i d deposition.

I n c l e a n environments such s o i l s mainly a c i d i f y by l o s s of

c a t i o n s (Ca, Mg, K and N a , C02,

organic

deposition, important,

acids

and

p l u s small amounts of A l i n p o d z o l i c s o i l s ) due t o uptake

d i s s o l u t i o n of

base

by

plants.

With

increasing

atmospheric

i n o r g a n i c A l i n a c i d i c s o i l s becomes i n c r e a s i n g l y

and Al may e v e n t u a l l y become t h e dominant c a t i o n , w i t h SO4 and NO3

as accompanying a n i o n s ( T a b l e 2 ) . TABLE 2 The chemical c o m p o s i t i o n of s o i l s o l u t i o n s from t h e Bhs horizon i n f o u r p o d z o l i c s o i l s (Typic Haplorthod) from Denmark ( s i t e s 1 and 2 ) and t h e N e t h e r l a n d s ( s i t e s 3 and 4 ) , sampled i n December 1985. V e g e t a t i o n cover is Calluna v u l g a r i s (1, 3 ) , P i c e a a b i e s ( 2 ) and Pinus s i l v e s t r i s ( 4 ) . Al is mainly f r e e u3+ a t a l l sites.

site no

estimated acid input kmol/ha.yr

PH

1

0.3

4.5 4.4 4.2 4.1

2 3 4

1.0

2.0 3.5

Ca

Mg

K

Al

Na

NO3

SO4

C1

126 406 892 1578

989 1458 349 481

equivalent ionc concentration,

High c o n c e n t r a t i o n s of

88

10

84 74

227 135 39 117

15 41 3 72

596 1120 202 250

141 546 960 2350

0 0 0 1440

d i s s o l v e d aluminum a s s o c i a t e d w i t h s t r o n g a c i d a n i o n s

( s u l f a t e and n i t r a t e ) i n f o r e s t s o i l s o l u t i o n s i n p o l l u t e d areas have a l s o been d e s c r i b e d from t h e FRG ( r e f .

9 ) and Sweden ( r e f .

10). In

S o l l i n g , FRG,

a

d i s t i n c t e v e n t i n t h e s o i l a c i d i f i c a t i o n p r o c e s s w a s observed i n t h e c o u r s e of the

chemical

monitoring

carried out

there

since

1969:

t h e c o n c e n t r a t i o n of

aluminum i n t h e s o i l s o l u t i o n a t 100 cm d e p t h i n a c i d brown f o r e s t s o i l s under s p r u c e i n c r e a s e d from between 2 and 8 mg/l

b e f o r e 1975, t o between 14 and 24

145 mg/l after 1977 (ref. 12). Evidence for a depression of soil pH by atmospheric deposition from "old" and "new" soil samples has been described from the FRG (refs 13 and 14), Austria (ref. 15) and from southern Sweden (refs 11 and 16). slightly to strongly acidic forest soils (pH 5 to 3.5)

The pH values of

in these areas have

decreased further over the past 5 to 55 years. One problem with this approach is that the pH of the surface soil tends to decrease with the age of the forest stand, due to formation of an organic forest floor and the assimilation of base cations by the vegetation. I n the work by Hallblcken and T a m (ref. 11) the effects of stand age and of year of sampling (resp. 1927 and 1984) have been separated (Fig. 1). The results show that between 1927 and 1982 the soil pH has (in the humus layer), 0.5

decreased by 0.3

(A2 and B horizons) and 0.7

(C

horizon) by some process not related to the vegetation, most likely as a result of acid atmospheric deposition. This conclusion is further corroborated by a parallel

study in northern Sweden, where atmospheric acid

deposition is

negligible. There the same relationship between stand age and soil pH was observed, but

pH values

significantly (C.O.

of

"old"

and

of

"new"

samples did

not differ

T a m , pers. comm.).

Modelling work, for example at IIASA (ref.

17).

shows that the observed

decreases in pH in acidic forest soils discussed above can indeed be explained, given

the

ambient

substances in the

rates

of

soil and

atmospheric

deposition,

pools

of

buffering

reasonable estimates for rates of

buffering

processes. EVIDENCE FOR INCREASED N LEVELS IN SOILS AND DRAINAGE WATER

On a molar basis, the wet and dry atmospheric deposition of nitrogen (as ammonia, ammonium and nitrate) in forest ecosystems in Western Europe (as indicated by fluxes in throughfall water) is in the same order as that of sulfur (ref. 18).

Particularly high rates of N deposition as ammonia occur in

areas with intensive animal production, e.g. (ref.

19).

in large parts of the Netherlands

Although historic data are lacking, ammonia deposition in the

Netherlands has undoubtedly increased dramatically during the past decades. Over much larger areas in the industrial world, wet deposition of nitrate has increased

strongly

since

last

deposition of nitrogen may assimilate all or most

of

century

(ref.

20).

In some forest areas

now exceed the capacity of the ecosystems to the nitrogen.

This is indicated by

increased

concentration of nitrate in soil solutions, ground- and stream water draining forested areas (refs 21,

22 and 23).

Acidification as a result of

nitrate

formation (microbial nitrification) is generally believed to stop when the pH falls below 4.

However in most

forest soils, contrary to arable soils,

nitrification can continue to values as low as 3 (refs 24,

25,

26 and 27).

146 Therefore, "saturation" of the ecosystem by nitrogen involves the danger of increased soil acidification by nitrification. The situation becomes worse when, for whatever reason, the vitality of the trees (and hence the capacity of the ecosystem to assimilate nitrogen) decreases: nitrate (in fact nitric acid) formed by nitrification of mineralized organic nitrogen is not taken up by plants and microorganisms, but is free to mobilize base cations and aluminum, and to depress soil pH. Various studies (refs 22, 23 and 2 8 ) provide evidence that this chain of events does take place indeed. ECOLOGICAL EFFECTS OF SOIL ACIDIFICATION The cause of the widespread forest decline reported from various mid- and western European countries is now generally thought to be related to air pollution.

It is not clear, however, whether air pollutants exert their

influence mainly directly by affecting above-ground parts of the vegetation (leading

to decreased photosynthesis),

or mainly

indirectly through soil

acidification followed by impairing the functioning of roots. For instance, the

,K

low levels of Mg

and Ca observed in many damaged forest stands h t h e FRG,

and the positive effects of fertilizing affected trees (see e.g. Baule, ref.

29)

the review by

can be explained either by direct effects of pollutant on

leaves, or by the effects of increased soil acidification (increased leaching of base cations; A1 toxicity).

Root growth seems to be invariably depressed in

affected forest stands in the FRG (ref. 3 0 ) , and could also result either from high levels of dissolved Al in the soil, or from decreased photosynthetic activity due to direct effects of pollutants on leaves. But measurements of root biomass dynamics and of the starch content of fine roots of norway spruce indicate

that

adverse

soil

conditions are

probably

more

important

than

depressed photosynthesis in affecting root growth (ref. 30). Effects of soil acidification on plants, microbes and soil fauna are highly complex.

We will

briefly discuss some of

the results obtained with

(1)

experimental acidification of soils ( 2 ) pot- or nutrient solution studies with plants,

and

(3)

correlative field studies on

vegetation and atmospheric

depostion. Many field- and pot experiments about the effects of soil acidification on vegetation, soil micro-organisms and soil biota have been done by applying simulated acid precipitation and by recording changes in the biota. Often, the maximum deposition rates applied are up to two orders of magnitude higher than in actual field conditions (e.g. 4.5)

simultated acid rain of pH 2.5

in stead of

to mimmick the effect of prolonged (decades to centuries, rather than

years) acid deposition. A review of many of such studies has been prepared by the V D I (ref. 18).

Both positive and negative effects of artificial acid rain

on trees (refs 31 and 32) and spil fauna (ref.

33) have been reported. This

147 ambiguity is not surprising considering the complicated mix of potentially beneficial effects (increased supply of N, S, and, at least on the short term, base cations) and potentially harmful effects (increased levels of dissolved A1 and, on the longer term, decreased levels of base cations) of adding large amounts of acid to a soil in a short period. Most pot- or nutrient solution studies on the effects of acid deposition on plants deal with the effects of aluminum. It is generally agreed that high levels of dissolved inorganic Al (i.e. harmful to plants. levels of

Al not complexed by organic ligands) are

This knowledge plus the observation that soil solution

inorganic Al

have

increased as a

deposition, is the basis of Ulrich's

result of

acid atmospheric

hypothesis of Al toxicity as a major

factor affecting forest ecosystems (ref. 9). The aluminum toxicity question is, however, very complex. Particularly with trees that grow normally or often in acidic soils (norway spruce, scots pine, birch, beech),

levels of dissolved

aluminum reported to have harmful effects varied widely, from lower than those found

frequently

in

strongly

acidified

(2

soils

10 mg/l)

to

concentration rarely observed in the field (20-50 mg/l)

(ref.

to

36).

high These

results always refer to seedlings. Low concentrations of dissolved Ca increase the susceptibility for Al

of spruce and beech

dissolved Ca/Al or (Ca+Mg)/Al

(ref.

34),

and ratios of

may be ecologically more relevant than absolute

Al-concentrations. High concentrations of nitrate increased the susceptibility of different grasses for dissolved Al (ref. 37).

Whereas these results do not

prove that Al toxicity plays an important role in forests affected by acid rain,

they

certainly

do

not

exclude A l

as an important adverse factor.

Concentrations of other potentially toxic cations such as Mn and various heavy metals can also increase to dangerous levels as a result of soil acidification, and these may be involved locally in depressed growth of trees and herbaceous plants, for instance at sites of stemflow infiltration adjacent to beech trees (ref.

38).

contact

In the Netherlands high concentrations of ammonium in water in

with

leaves

and

shallow roots may

induce deficiencies of

other

nutrients in trees, in particular of K and Mg (ref. 39). For epiphytic lichens, certain mushrooms (Cantharellus cibarus) and a number of herbaceous plants, the decline in occurrence between 1950 and I980 in the Netherlands,

and

the

concentrations of

SO2

in

the

air

were

spatially

correlated, suggesting a causal relationship involving direct or indirect effects of air pollution (ref. 40). Wittig and coworkers (refs 41 and 42) have observed a significant increase in acidophilic plants in the herb layer of Westphalian beech forests between 1976 and 1983. The studies cited above do not, and could not, prove conclusively that soil acidification by air pollution has important and often adverse effects on forest ecosystems, but in our opinion there can be little doubt that such

148 effects occur. CRITICAL LOADS OF ACIDITY AND NITROGEN ON TERRESTRIAL ECOSYSTEMS Because inorganic dissolved aluminum is generally thought to play a key role in toxicity problems in both the terrestrial and aquatic environment, inorganic aluminum in soil solutions is often used as an indicator for potential adverse effects from atmospheric acidic deposition. Total dissolved aluminum is not suitable for this purpose, because the organically complexed aluminum commonly present in soil solutlons of naturally acidic soils (Spodosols) is generally not toxic. At the workshop on "Critical Loads for Effects of Sulphur and Nitrogen Deposition on Forest Soils, Groundwater and Surface Water" held in Oslo (ref. 4 3 ) it was agreed that input of potentially acidic substances in soils should be

limited

to

levels which will only cause a negligible mobilization of

inorganic aluminum in most acidic s o i l s .

Negligible mobilization of inorganic

Al mobilization in soils is essential in areas where soil drainage water directly enters a surface water body, because aquatic organisms are generally more sensitive than terrestrial organisms to dissolved inorganic aluminum. Mobilization of

inorganic aluminum is insignificant if total acid inputs

(anthropogenic and natural) do not exceed the rate of weathering of

base

cations from primary minerals. At the Oslo Workshop, acceptable atmospheric acid loads were estimated from current base cation weathering rates in acidic soils (Spodosols, Acid Brown Forest Soils), using input/output studies (both for catchments and individual soil profiles) carried through in Scandinavia, central Europe and the Netherlands. Reported values for acceptable atmospheric acid loads range from 0.05 H+/ha.yr

to 0.75 kmol H+/ha.yr

(ref. 4 3 ) ; 0.1

to 0.2 kmol

would probably not cause inorganic aluminum mobilization in most

European acidic soils. It ahould be realized, however, that the weathering rate of primary minerals decreases upon prolonged soil acidification, so that in the long rund the acceptable acid load will decrease. For comparison, the current atmospheric acid input in southern Scandinavia is about 1 kmol H+/ha.yr, while in Central Europe the acid inputs often exceed 3 kmol H+/ha.yr. The crital values indicated above may not apply to the very sensitive soils in large parts of the Netherlands, northern FRG and western Jutland, which have developed in sandy deposits, that are extremely poor in weatherable silicate minerals.

Such sQils show essentially no

base

cation leaching.

In fact,

atmospherically supplied nutrient base cations are retained in the ecosystem (Mulder,

unpublished).

neutralieed

by

In these acidic soils any atmospheric acidity is

aluminum

solubilization

(ref.

44).

So,

to

prevent

A1

mobilization, the atmospheric acid load would have to be close to 0 kmol H+/ha.yr!

Because (1) terrestrial organisms appear

LO

be less suceptible to

inorganic aluminum than aquatic organisms and (2) acidic, sandy soils in the Netherlands hardly ever generate suface water, mobilization of limited amounts of aluminum by atmospheric acidic deposition in the Netherlands is probably

<

acceptable. Molar ratios of dissolved (Ca+Mg)/Al

1 have been proposed to

indicate potential adverse effects on tree growth in sensitive sandy forest soils in the Netherlands (ref. 4 5 ) . Dissolved (Ca+Mg)/Al

ratios

<

1 in the

rooting zone occur when total atmospheric acid loads exceed 1 kmol H+/ha.yr the most sensitive sandy forest soils, or 1.4

kmol H+/ha.yr

in

in acid brown

forest soils in the Netherlands. Current total acid loads in forest soils in the Netherlands are 3 to 6 kmol/ha.yr. I n most terrestrial ecosystems in the world increased atmospheric deposition

of NOx and NH3 would

increase primary production.

With continued high N

deposition, however, other nutrients or toxic factors would limit or decrease primary production, and essentially all added nitrogen would be leached from the system.

Information s o far indicates that in most N-saturated

systems

nitrogen is leached in the form of nitrate. Many woodlands in the Netherlands, are saturated with nitrogen due to a prolonged high deposition of NH3, and nitrification

and

the

subsequent

leaching

of

nitrate

cause

severe soil

acidification. Soil acidification, imbalance in nutrients and increased nitrate concentrations in groundwater, can be decreased when N-saturation is avoided.

In the

long

term, the critical nitrogen load in ecosystems must

be

determined by the net uptake in plants in the standing biomass (ref. 4 3 ) . Andersen (ref. 4 6 ) estimates the net growth increment in the woody vegetation of coniferous trees to be 0.4

to 1.0 kmol N/ha.yr

at sites with low to medium

productivity in Europe and north America. In the Netherlands the net annual nitrogen uptake in the woody biomass of pine is in order of 0.4 kmol/ha.yr for pine, and 0.4

to 1.3

kmol/ha in an oak-birch woodland (ref.

deposition rates of nitrogen (NH3 be around 0.4

kmol/ha.yr.

now exceeds 1.5

+

47).

So,

safe

NO3) at sites with a low productivity would

I n south Scandinavia the annual total N deposition

kmol/ha, while in central Europe the annual N deposition is

between 2 and 3 hol/ha.

In the Netherlands the annual deposition of N on

forests ranges from 3 to 4.5 kmol/ha. Natural background values, e.g.

in remote

areas in Canada, are less than 0.1 kmol N/ha.yr (ref. 4 8 ) .

As indicated above it is important for both forest vitality and the quality of

drinking

water

supplies to

reduce the

current N

deposition in the

Netherlands by 90%. At such levels of N deposition, nitrogen can be completely assimilated by the standing biomass and therefore can no longer cause soil acidification. The current deposition of 2.4

to 4.0

equivalent kmol S/ha.yr in

the Netherlands should be reduced by at least 75% in order to keep aluminum concentrations in the soil solution within acceptable limits.

150 ACKNOWLEDGEMENTS For the data of Table 2 we like to thank Ing. H.W.G.

Booltink (Agric. Univ.,

Wageningen) and Dr. L. Rasmussen (Techn. Univ. Denmark) for sampling, and E.J. Velthorst, A. van Osch and N. Nakken-Brameyer of our department for the water analysis. Further thanks are due to J.E.

Handberg, W.A.M.

Rijken and the State

Forest Service in the Netherlands for allowing us to use the research sites in Denmark and in the Netherlands. These investigations were supported in part by the Netherlands Technical Foundation (STW). REFERENCES 1

2 3 4 5 6

7 8

9

10 11 12 13 14 15 16

17

18 19 20 21 22 23

M.A. Tabatabai, CRC Crit. Rev. Environ. Cont. 15 (1985) 65-110. N. van Breemen, J. Mulder, C.T. Driscoll, Plant and Soil 75 (1983) 283-308. J.J.M. van Grinsven, F.A.M. de Haan and W.H. van Riemsdijk, in T. Schneider (Ed.) Acidification and its policy implications, Elsevier, Amsterdam 1986, this volume. C.T. Driscoll, and G.E. Likens, 1982. Tellus 34 (1982) 283-292. N. van Breemen, C.T. Driscoll, J. Mulder, Nature 307 (1984) 599-604. N. van Breemen, P.H.B. de Visser and J.J.M. van Grinsven, Journal Geol. SOC. London, 143 (1986) in press. A. Breeuwsma and W. de Vries. Neth. J. Agric. Sci. 32 (1984) 161-163. H. Foelster, in J.I. Drever (Ed.) The chemistry of weathering. NATO AS1 series, D. Reidel Publ. Co., Dordrecht. 1984, pp. 197-209 B. Ulrich, R. Mayer und P.K. Khanna, Die Deposition von Luftverunreinigungen und ihre Auswirkungen in Waldoeksysteme in Solling. Schriften Forstl. Fak. Univ. Goettingen, Bd 58 ( 1 9 7 9 ) , p. 291 S.I. Nilsson, and B. Bergkvist. Water Air Soil Pollut. 20 (1983) 311-329. L. Hallbzcken and C.O. Tamm, Changes in soil acidity from 1927 to 1982-84 in a forest area of Southwest Sweden.Scand. J. For. Res. Vol 1 (1986) in press E. Matzner, P.K. Khanna, K.J. Meiwes, M. Lindheim, J. Prenzel und B. Ulrich. Elementfltisse in Waldoekosystemen im Solling. Daten dokumentation. GGttinger Bodenk. Ber. 71 (1985) p. 267. B. Ulrich, R. Mayer und P.K. Khanna, Soil Sci. 130 (1980) 193-199 H. Butzke. Forst- und Holzwirt 21 (1981) 542-548. G. Glatzel, und M. Kazda, Z. Pflanzenernaehr. Bodenk. 148 (1985) 429-438. G. Tyler, D. Berggren, B. Bergkvist, U. Falkengren-Grerup, L. Folkeson and A. REling, in T.C. Hutchinson (Ed.) Effects of Acidic deposition on forests, wetlands, and agricultural ecosystems. NATO AS1 Series, Springer Verlag, Berlin, 1986, in press P. Kauppi, J. KZmzri, M. Posch, L. Kauppi, E. Matzner. Acidification of forest soils: a model for analyzing impacts of acidic deposition in Europe, version 11. Collaborative Paper 27 of the International Institute for Applied Systems Analysis, Laxenburg, Austria, 1985, 28p. VDI Kommission Reinhaltung der Luft, SPurehaltige Niederschlzge: Entstehung und Wirkungen auf terrestrische Oekosysteme, Diisseldorf, 1984, p. 277 N. van Breemen, P.A. Burrough, E.J. Velthorst, H.F. van Dobben, T. de W i t , T.B. Ridder and H.F.R. Reijnders. Nature 299 (1982) 548-550. P. Brimblecombe and D.H. Stedman. Nature 298 (1982) 460-462. R. Schoen, R.F. Wright and M. Krieter. Regional survey of freshwater acidification in West Germany (FRG). Norwegian Institute for Water Research NIVA. Acid Rain Res. Rep. 5 / 8 3 (1985) 15p. M. Hauhs. Wasser- und Stoffhaushalt im Einzugsgebiet der Langen Bramke (Harz). Berichte des Forzungszentrums Waldoekosysteme/Waldsterben, Goettingen, 1985, Bd. 17, p. 206 N. van Breemen, J. Mulder amd J.J.M. van Grinsven, Hydrochemical budgets of woodlands soils affected by atmospheric acid deposition. I1 Ntransformations. Soil Sci. SOC. her. Journal, subm. for publ.

151 24 G.P. Robertson, Phil. Trans. R. SOC. Lond. B 296 (1982) 445-447. 25 W.U. Kriebitzsch. Stickstoffnachlieferung in sauren Waldbaden Nordwestdeutschlands. Scripta Geobotanica 14. Verlag E. Goltze. 1978, 66p. 26 H. Mai, und H.J. Friedler. Arch. Acker- U. Pflanzenbau U. Bodenkd. 27 (1983) 499-507. 27 J. Berthelin, M. Bonne, G. Belgy, F.X. Wedraogo. Geomicrobiology J. 4 (1985) 175-190. 28 T. Paces. Nature 315 (1985) 31-36 29 H. Baule. Allg. Forst 2. nr. 30/31 (1984) 4 p . 30 E. Matzner, in T.C. Hutchinson (Ed.) Effects of Acidic deposition on forests, wetland, and agricultural ecosystems. NATO AS1 Series, Springer Verlag, Berling, 1986 in press. 31 G. Ogner, and 0. Teigen, Plant and Soil 57 (1980) 305-321. 32 G. Abrahamsen. Phil. Trans. R. SOC. Lond. B30'5 (1984) 369-382. in J. Nilsson et al, (1986). 33 S . Hagvar. Pedobiologia 27 (1984) 341-354. Rost-Siebert. Untersuchungen zur Hund Al-Ionen-toxizitaet an 34 K. Keimpflanzen von Fichte (Picea Abies, Karst.) und Buche (Fagus Sylvatica, L.1 in Loesungskultur. Berichte des Forschungszentrums Waloekosysteme/Waldsterben, Goettingen: Bd. 12 (1985) 219p. 35 N.V. Hue, G.R. Craddock and F. Adam, Soil Sci. SOC. Amer. Journal 50 (1986) 28-34. 36 F. Anderson and J.M. Kelly (eds.) Aluminium toxicity to trees. Doc. Intern. Workshop, Uppsala, Sect. Systems Ecology, Swedish Univ. Agric. Sci. (1984) p. 154 37 J.H. Rorison, J. Ecol 73 (1985) 83-90 38 G. Glatzel, M. Kazda and L. Lindebner, Duesseldorfer Geobot. Kolloq. 3 (1986) 15-32 39 J.G.M. Roelofs, A.J. Kempers, A.L.F.M. Houdijk, J. Jansen. Plant and Soil 84 (1985) 45-56. 40 H.F. van Dobben, T. de Wit and D. van Dam. In: VDI-Berichte 500 (1983) 225229. 41 R. Wittig and H. Neite, Vegetatio 64 (1985) 113-119 42 G. Wittig, H.J. Ballach and C. Jeffrey Brandt, Angew. Botanik 59 (1985) 219232. 43 J. Nilsson et al.,. Final Report from the workshop on "Critical Loads for Effects of Sulphur and Nitrogen Deposition on Forest Soils, Groundwater and Surface Water" held in Oslo, April 7-10, 1986. 44 J. Mulder and N. van Breemen, 1985. in T.C. Hutchinson (Ed.). Effects of acidic deposition on forests, wetlands and agricultural ecosystems. NATO AS1 Series, Springer Verlag, Berlin 1986, in press 45 Ministry of Housing, Physical Planning and Environment, the Netherlands, 1986. Proposal for deposition limits of N and S, 1987-1991. 46 B. Andersen in J. Nilsson et al., (1986). 47 P.H.B. de Visser. Interaction between soil, vegetation and atmospheric deposition in some oak-birch and pine stands in the Netherlands. Dept. Soil Sci. and Geology, Agric. Univ. Wageningen, the Netherlands 1986, in press 48 G.J. Stensland, B.B. Hicks, W.B. Lyons, P.A. Mayewski. In: The acidic deposition phenomenon and its effects: critical assessment review papers. U.S. Environmental Protection Agency, 1983, Vol. I: Atmospheric Sciences A8.

152

pH

3

HUMUS LAYER

I

J

A2- HORIZON

I

B -HORIZON

I

C - HORIZON

I

_.-1927

-1981 3

I

1

15 2

3

5

8 1213

l

l

I

I 1

25324058 8898

years after clearcutting or plcmting F i g . 1. S o i l pH ( i n water) a g a i n s t t i m e a f t e r c l e a r c u t t i n g o r planting i n f o r e s t soils i n Southern Sweden, f o r samples taken in 1927 and 1984 (Reproduced by permission from Hallblcken and Tamm, r e f . 1 1 ) .

T. Schneider (Editor)/Acidification and its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

ATMOSPHERIC DEPOSITION:

153

IMPACT V I A SOIL BIOLOGY

SIGMUND HAGVAR

Norwegian F o r e s t Research I n s t i t u t e , 1432 As-NLH, Norway

ABSTRACT The growth o f t r e e s depends on n u t r i e n t s which a r e released by decomposition processes i n t h e s o i l . These processes a r e v e r y complex and p o o r l y understood, b u t they a r e c l e a r l y r e l a t e d t o t h e b i o l o g i c a l a c t i v i t y o f t h e s o i l . Two main groups o f s o i l organisms cooperate i n t h e decomposition processes: t h e s o i l animals and t h e s o i l m i c r o f l o r a ( f u n g i and b a c t e r i a ) . Our knowledge about p o s s i b l e e f f e c t s o f s o i l a c i d i f i c a t i o n on decomposition processes and s o i l organisms a r e m a i n l y based upon experiments w i t h a r t i f i c i a l a c i d r a i n . Most a c i d i f i c a t i o n experiments have r e s u l t e d i n reduced decomposit i o n r a t e s ( f o r i n s t a n c e raw humus, b i r c h leaves o r needle l i t t e r ) . Important processes as N - f i x a t i o n , n i t r i f i c a t i o n and d e n i t r i f i c a t i o n a r e a l s o known t o be pH-dependent. F i e l d experiments w i t h strong a c i d i f i c a t i o n have reduced t h e amounts o f f u n g i and b a c t e r i a i n t h e s o i l . Also many groups and species o f s o i l animals were a f f e c t e d , some o f them i n c r e a s i n g t h e i r abundance and some decreasi n g i n numbers. The abundance o f several s o i l animals seems t o be g e n e r a l l y r e l a t e d t o s o i l pH. We may conclude t h a t many processes t h a t a r e important f o r p l a n t growth a r e suppressed as t h e pH declines. The p r a c t i c a l i m p l i c a t i o n o f t h i s statement i s , however, n o t easy. Several o f t h e r e s u l t s r e f e r r e d t o appeared i n experiments w i t h v e r y s t r o n g a c i d s ( f o r i n s t a n c e pH 2.5 o r pH 2). Secondly, we know very l i t t l e about how much t h e s o i l pH may change due t o t h e a c i d p r e c i p i t a t i o n . T h i r d l y , d i f f e r e n t s o i l types r e a c t d i f f e r e n t l y t o a c i d i f i c a t i o n . I t becomes a p o l i t i c a l q u e s t i o n whether t h i s doubt s h a l l a l l o w f o r a f u r t h e r spread o f a c i d p r e c i p i t a t i o n , o r whether we decide n o t t o experiment w i t h nature. INTRODUCTION The growth o f every f o r e s t depends on n u t r i e n t s which a r e released by decomp o s i t i o n processes i n t h e s o i l . i s m s , t h a t cooperate

These processes a r e r e g u l a t e d by l i v i n g organ-

i n a v e r y complex manner.

changes t h e chemical o r p h y s i c a l c o n d i t i o n

I f atmospheric d e p o s i t i o n o f t h e s o i l , t h i s may a f f e c t t r e e

growth i n d i r e c t l y v i a , f o r instance, a reduced decomposition r a t e . The p o s s i b l e e f f e c t s o f a c i d p r e c i p i t a t i o n on s o i l b i o l o g i c a l processes a r e d i f f i c u l t t o study. r e l a t i v e l y poor.

F i r s t l y , o u r general knowledge about these processes are

T h i s means t h a t we have d i f f i c u l t i e s even i n f o r m u l a t i n g t h e

c o r r e c t questions.

Secondly, most o f t h e experimental approaches a r e o f t h e

" b l a c k box" type, which means t h a t e f f e c t s a r e s t u d i e d w i t h o u t l e a r n i n g t h e r e l e v a n t mechanisms. spect.

T h i r d l y , experiments a r e always " a r t i f i c i a l " i n some r e -

C o n t r o l l e d l a b o r a t o r y experiments have t o be s i m p l i f i e d , and f i e l d

experiments w i t h s t r o n g a c i d s do n o t n e c e s s a r i l y m i r r o r t h e long-term e f f e c t s

154 of weaker acids. A fourth point i s t h a t we have t o o few older soil analyses t o document whether a s o i l acidification really has occurred. What we can d o , i s t o discuss some soil processes and s o i l organisms which we think a r e important, and sum up the present knowledge about how these may be affected by a soil acidification. The main point will be the a v a i l a b i l i t y of plant nutrients, s o decomposition r a t e s a r e of great i n t e r e s t . First,however, we should have a look a t the soil organisms regulating the decomposition. These can be divided into two main groups: the microflora (fungi and bacteria), and the soil animals. SOIL MICROFLORA Alexander ( r e f . 1 ) has drawn up some major relationships between microflora and soil acidity. Generally, i t i s assumed that the number of bacteria are reduced by increased soil acidity (low pH), while the amount of fungi may increase. Because we know too l i t t l e about the function of different groups of bacteria and fungi, i t i s d i f f i c u l t t o r e l a t e changes in microflora directly t o the a v a i l a b i l i t y of plant nutrients. However, some important processes are goverened by certain s p e c i f i c organisms. N-fixating Rhizobium-bacteria i n roots of Leguminosae a r e s e n s i t i v e t o pH values below 4.6. Even N-fixating blue-green algae are acid sensitive. Bacteria transforming NH4 t o NO3 ( n i t r i f i c a t i o n ) rarely occur below pH 5. Also d e n i t r i f i c a t i o n i s affected by soil pH. Clearly, increased s o i l a c i d i t y can cause many changes in microbiological populations and processes. These changes could slow mineralization and thus reduce nutrient a v a i l a b i l i t y t o plants ( r e f . 2 ) . Mykorrhiza i s another important feature which might be affected by soil acidification, and which should be studied closer ( r e f . 3). S t r o n g experimental acidification of coniferous f o r e s t plots have affected the microflora. By application of pH 2-water, both soil respiration, bacterial s i z e and the number of FDA-active bacteria were reduced ( r e f . 4 ) . In another parallel study, application of 150 kg HzSO4 per ha and year over six years reduced the amount of FDA-active fungi b o t h in the organic layer and in the bleached layer ( r e f . 5 ) . Different fungal species isolated from Pinus contorta needles had d i f f e r e n t pH-preferences (ref.6). The present-day information shows that s o i l acidification may have severa negative e f f e c t s on the microflora and the processes which regulate the amount of plant nutrients in the s o i l . SOIL FAUNA A rich f o r e s t soil may contain u p t o one thousand species of small animals. mz. Table 1 shows the approximate

Their abundance reach many millions per

155

TABLE 1 Body length and abundance of some s o i l animals i n a Norwegian blueberry spruce f o r e s t .

Body length One-celled animals (Protozoa) Nematodes Mites (Acari ) S p r i n g t a i l s (Col lembol a ) Enchytraeids Earthworms

0.1- 0.2 0.5-10 0.5- 1 0.5- 1 1 - 5 2 -30

mm

mm mm mm mm cm

-

Abundance per m 2 150 000 000 10 000 000 500 000 100 000 50 000

25

abundance of various s o i l animals i n a Norwegian spruce f o r e s t with blueberry vegetation. The r o l e of s o i l animals i s s t i l l poorly known, b u t most s t u d i e s show t h a t they speed u p the decomposition r a t e and c o n t r i b u t e t o t h e r e l e a s e of plant n u t r i e n t s (e.g. r e f . 7 ) . For i n s t a n c e , i t has been shown t h a t t h e grazing of microarthropods (Collembola and Acari) on fungal colonies can s t i m u l a t e t h e growth and a c t i v i t y of the fungus (e.g. r e f . 8 ) . Fig. 1 shows two microarthropods (a collembole and a box mite) feeding on a fungal colony. S i m i l a r l y , c l o s e r e l a t i o n s h i p s e x i s t between the amount of b a c t e r i a and bacterial-feeding Nematoda o r Protozoa. Soil animals a l s o fragment the l i t t e r and humus and contribute t o the spreading of fungi and b a c t e r i a . Some animals have the necessary enzymes t o d i g e s t the dead p l a n t remnants d i r e c t l y .

Fig. 1.

A s p r i n g t a i l ( l e f t ) and a box mite ( r i g h t ) feeding on a fungal colony.

In Norway, a research program has been r u n f o r several years concerning poss i b l e e f f e c t s of acid r a i n on coniferous f o r e s t . The s o i l zoological p a r t of t h i s p r o j e c t followed three d i f f e r e n t approaches: 1 . Col oni s a t i o n experiment. Mi croarthropoda and Enchytraei dae were a1 1owed t o c o l o n i s e and reproduce i n s o i l samples which had been adjusted t o d i f f e r e n t pH levels (ref.9). 2. Field experiments with a r t i f i c i a l acid r a i n and liming.

In coniferous f o r e s t

156 w i t h podzol s o i l (Typic Udipsamment), experimental p l o t s were e i t h e r limed o r t r e a t e d w i t h a r t i f i c i a l r a i n o f pH 6 ( c o n t r o l ) , 4, 3, 2.5 o r 2. E f f e c t s were described on Protozoa, R o t i f e r a and Nematoda ( r e f . l O ) , on Acari ( r e f . l l ) , on Enchytraeidae ( r e f . 1 2 ) and on Collembola and Protura (ref.13).

Effects o f a r t i -

f i c i a l a c i d r a i n on microarthropods were a l s o s t u d i e d i n decomposing b i r c h leaves, both i n t h e f i e l d and i n a greenhouse experiment (ref.14). 3. The d i s t r i b u t i o n o f microarthropod species i n n a t u r a l s o i l s o f d i f f e r e n t pH.

This was considered t o be an important c o n t r o l o f the experimental r e s u l t s .

If

a general r e l a t i o n s h i p e x i s t s between s o i l pH and t h e abundance of a given species, t h i s should a l s o be r e f l e c t e d under n a t u r a l f i e l d conditions (ref.15,

16).

We found t h a t s o i l pH i s an important f a c t o r f o r many species and groups o f s o i l animals.

The two f i r s t approaches gave very s i m i l a r r e s u l t s , and the main Most e f f e c t s i n t h e f i e l d experiments were

conclusions are l i s t e d i n Table 2.

achieved a t t h e two strongest treatments, w i t h a r t i f i c i a l a c i d r a i n of pH 2.5 o r 2.

In these treatments, t h e s o i l pH was a l s o s i g n i f i c a n t l y reduced.

Many

groups reacted n e g a t i v e l y on both a c i d i f i c a t i o n and l i m i n g , showinq t h a t they a r e adapted t o t h e i r normal s o i l pH.

Among Acari and Collembola, d i f f e r e n t

species reacted i n d i f f e r e n t ways, c r e a t i n g a complex p i c t u r e .

Acidification

TABLE 2 E f f e c t o f strong a c i d i f i c a t i o n and l i m i n g on d i f f e r e n t s o i l animals.

The symbol

+ means increased abundance, and the symbol - means reduced abundance as a consequence o f t h e treatment.

Symbols i n brachets i n d i c a t e n o n - s i g n i f i c a n t trends.

Protozoa

Tes tacea C i l iata

-

(- 1

(several species)

(-

Nemat oda

(-1 -

Acari (mites) T o t a l Acari Species l e v e l

- +

Col 1embol a ( s p r i n g t a i 1s ) T o t a l Col 1embol a Species 1eve1

- + (7

-

+

+

-

(several species)

1

Rot if era

Enchytraeidae (mainly one species)

Liming

Acidification

Group

( 3 species) (8 species)

species) ( 6 species)

-

+

-

-

+

(17 species) ( 3 species)

( 7 species) ( 5 species)

157

might increase o r decrease the total abundance of Collembola o r Acari, b u t in the strongest a c i d i f i c a t i o n , both groups were reduced in abundance. The third approach confirmed t h a t soil pH has a general regulating e f f e c t on the soil fauna. For instance, species which were disfavoured by a r t i f i c i a l acidificat i o n , were a l s o rare in naturally acid s o i l s . Fig. 2 A-B show how the composition of the Acari and Collembola cornunities change from limed s o i l , via control soil t o strongly acidified soil in the f i e l d experiments. Among Acari, an acidification induces an increased dominance of Oribatei. The Collembola community in strongly acidified soil i s dominated by two species, which together make up 60% of the t o t a l . Several of the reactions among microarthropods are confirmed by a Swedish acidification experiment ( r e f . 5) and a Finnish 1 iming experiment ( r e f . 1 7 ) . There i s no simple explanation t o the observed e f f e c t s , and different groups may probably be affected by d i f f e r e n t mechanisms. Possible hypotheses f o r microarthropods have been discussed ( r e f . 18). For t h i s group, laboratory experiments indicate that competition may be a crucial f a c t o r , and t h a t the soil acidity a f f e c t s the competition success of the various species. Earthworms were p r a c t i c a l l y absent from the s o i l s in the referred studies. However, i t i s well known t h a t earthworms are sensitive t o changes in soil pH, and t h a t very acid s o i l s contain both few species and individuals (e.g. ref.19). The conclusion regarding s o i l fauna i s similar t o t h a t of soil microflora: The s o i l a c i d i t y i s an important f a c t o r which affects the abundance both a t species and group level. Our understanding i s , however, small , both concerning the mechanisms and the impact on nutrient a v a i l a b i l i t y . The combined e f f e c t of changes in microflora and soil fauna i s , on the other hand, expressed t h r o u g h the decomposition rate. Therefore, we shall proceed by lookinq a t the effects of acidification on decomposition rates. DECOMPOSITION RATES In naturally acid s o i l s , decomposition rates a r e often slow, and acidity i s generally 1 inked w i t h decreased rates of humus decomposition ( r e f . 1 ). Model s have been made where increased acidification induces reduced decomposition r a t e and reduced a v a i l a b i l i t y of nitrogen (ref.20). In the following, weshall discuss a number of decomposition experiments, where the soil pH has been manipulated. Raw humus incubated with sulphuric acid or powdered sulphur showed a reduced C O 2 production, which indicated lowered microbial a c i t i v i t y and decomposition r a t e (ref.21). In the Swedish f i e l d studies with a r t i f i c i a l acidification, a reduced decomposition r a t e of surface needle l i t t e r was noted a f t e r two years, b u t no e f f e c t on root l i t t e r placed i n the Of/Oh-layer a f t e r 1 year ( r e f . 5 ) . In a Norwegian study, application of pH 2-water reduced the decomposition r a t e of birch leaves i n a 9reenhouse experiment, while corresponding trends

158

-100

- 90 - 80

PROSTIGMATA MESOSTIGMATA

- 70 - 60

ASTIGMATA

A -50

N. SILVESTRIS

-40

T. VELATUS

- 30 - 20

6.ZEIAWAIENSIS

I

OTHER ORlEATEl

0 R

- 10 L

7-

B.

LIME

i

pH 2 5

%

,.,.

OTHER COLLEMBOLA ONYCHIURUS ARMATUS S.L. ONYCHIURUS ABSOLONI ISOTOMIELLA MINOR ISOTOMA NOTABlLIS

B

ANURIDA WGMAEA ME&PHORURA LIME

pH 2.5

F i g . 2. E f f e c t s o f l i m i n g and a r t i f i c i a l a c i d r a i n on t h e A c a r i community ( A ) and t h e Collembola community (B). The t h e c o n t r o l ( a p p l i c a t i o n o f ground w a t e r ) . A l s o t h e l i m e d same amount o f ground water. To t h e r i g h t : e f f e c t s o f t h e a c i d " r a i n " o f pH 2.5 and 2. P r i n t e d w i t h p e r m i s s i o n from Oikos and P e d o b i o l o g i a .

composition of pH 6 - t r e a t m e n t p l o t s received application o f

the is the very

159 were found i n t h e f i e l d (ref.14). The same f i e l d experiment gave reduced decomposition r a t e s o f c e l l u l o s e a t t h e pH 2.5-treatment, w h i l e weight l o s s o f aspen wood pieces were n o t s i g n i f i c a n t l y a f f e c t e d (ref.22).

Strong a c i d i f i c a -

t i o n o f spruce o r p i n e needles ( w i t h s u l p h u r i c a c i d o f pH between 2 and 3.1) have speeded up decomposition i n t h e e a r l y phase, b u t then reduced t h e decompos i t i o n r a t e i n a l a t e r phase ( r e f . 6 ,

23, 24).

I n a greenhouse experiment, a

l o w e r i n g o f t h e pH o f raw humus from 4.5 t o l e v e l s between 2.9 and 3.5 reduced s i g n i f i c a n t l y t h e decomposition r a t e ( r e f . 9 ) .

A l o w e r i n g o f s o i l pH from 4.6

t o 3.0 i n a sandy loam s o i l f r o m a n o a k - p i n e f o r e s t reduced t h e decomposition r a t e and t h e r a t e s f o r ammonification, n i t r i f i c a t i o n and d e n i t r i f i c a t i o n ( r e f . 25).

The authors f e a r e d t h a t f u r t h e r a c i d i f i c a t i o n o f a c i d f o r e s t s o i l s w i l l

reduce t h e n u t r i e n t c y c l i n g . CONCLUSIONS Our general knowledge about decomposition processes, as w e l l as experimental evidence, i n d i c a t e t h a t

soil acidification,

t r i e n t c y c l i n g and reduce f o r e s t Growth.

when i t occurs, may slow down nu-

Many processes t h a t a r e i m p o r t a n t f o r

p l a n t growth a r e c l e a r l y suppressed as t h e pH d e c l i n e s ( r e f . 1 ) .

Data from south

Sweden i n d i c a t e t h a t s o i l pH has been reduced i n f o r e s t s o i l d u r i n g t h e l a s t decades (ref.26).

Our a b i l i t y t o f o r e c a s t trends i n t h i s f i e l d i s , however,

l i m i t e d due t o few o l d e r , comparable pH-studies o f f o r e s t s o i l .

There a r e a l s o

considerable l o c a l d i f f e r e n c e s between s o i l s i n t h e i r a b i l i t y t o w i t h s t a n d acidification. On t h e p o l i t i c a l l e v e l , t h e doubt about t h e s i t u a t i o n may, o r may n o t l e a d t o any a c t i o n .

One view i s t o go on p o l l u t i n g , c o n t i n u o u s l y w a i t i n g f o r more

and more d e t a i l e d s c i e n t i f i c i n f o r m a t i o n about t h e e f f e c t s . t o decide t h a t we s h a l l n o t experiment w i t h nature.

The o t h e r view i s

The f o r e s t death i n middle

Europe showed us t h a t we a r e o f t e n unable t o foresee harmful e f f e c t s .

Nature

i s v e r y complicated, and we take a l a r g e r i s k by w a i t i n g f o r explanations. Even now, s c i e n t i s t s do n o t agree about t h e reasons f o r t h e f o r e s t death.

If

we d o n ' t want t o experiment w i t h nature, which i s a l s o t h e n a t u r e o f f u t u r e generations, t h i s d e c i s i o n must be taken now, and taken by t h e p o l i t i c i a n s . REFERENCES 1 M. Alexander, i n T.C. Hutchinson and M. Havas (Eds.), E f f e c t s o f A c i d P r e c i p i t a t i o n on T e r r e s t r i a l Ecosystems, Plenum Press, New York and London, 1980, pp. 363-374. 2 D.W. Johnson and D.S. S h r i n e r , i n T.C. Hutchinson and M. Havas (Eds.), E f f e c t s o f A c i d P r e c i p i t a t i o n on T e r r e s t r i a l Ecosystems, Plenum Press, New York and London, 1980, pp. 601-606. 3 T.C. Hutchinson, i n T.C. Hutchinson and M. Havas (Eds.), E f f e c t s o f A c i d P r e c i p i t a t i o n on T e r r e s t r i a l Ecosystems, Plenum Press, New York and London, 1980, pp. 617-627.

160

E. Bbdth B, Lundgren and B. SEderstrom, B u l l . Envirorl. Contam. Toxicol. , 2 3 (19793 737-740. 5 E. Bbbth, B. Berg, U. Lohm, B. Lundgren, H. L u n d k v i s t , T. Rosswall, B. S'dderstrijm and A. Wiren, P e d o b i o l o g i a , 20 (1980) 85-100. 6 Y. I s h a c and J . Hovland, I n t e r n a l Report 24, SNSF-project, NISK-As, Norway, 1976, 20 pp. 7 T.R. S e a s t e d t , Ann. Rev. Entomol., 29 (1984) 25-46. 8 R.D.G. Hanlon, Oikos, 36 ( 1 9 8 1 ) 362-367. 9 S. Hdgvar and G. Abrahamsen, O i k o s , 34 (1980) 245-258. 10 T. Stachurska-Hagen, I n t e r n a l Report 74, SNSF-project, NISK-As, Norway, 1980, 23 pp. 11 S. Hdgvar and T. Amundsen, O i k o s , 37 (1981) 7-20. 12 G. Abrahamsen, H o l a r c t . E c o l . , 6 (1983) 247-254. 1 3 S. Hbgvar, P e d o b i o l o g i a , 27 (1984) 341-354. 1 4 S. Hdgvar and B.R. Kjijndal, P e d o b i o l o g i a , 22 (1981) 409-422. 15 S. Hbgvar and G. Abrahamsen, P e d o b i o l o g i a , 27 (1984) 331-339. 16 5. Hbgvar, P e d o b i o l o g i a , 27 (1984) 355-364. 17 V. Huhta, R. Hyv'dnen, A. Koskenniemi and P. Vilkamaa, i n P. Lebrun, H.M. Andre, A. De Medts, C. Grggoire-Wibo and G. Wauthy ( E d s . ) , New Trends i n S o i l B i o l o g y , P r o c e e d i n g s o f the V I I I . I n t . C o l l o q . of S o i l Zoology i n 1982 a t Louvain-la-Neuve, Belgium, U n i v e r s i t g C a t h o l i q u e , 1983, pp. 61-73. 1 8 S. Hbgvar, E c o l o g i c a l S t u d i e s o f M i c r o a r t h r o p o d s i n F o r e s t S o i l s , w i t h Emphasis on R e l a t i o n s t o S o i l A c i d i t y . I n t r o d u c t i o n t o Doctoral D i s s e r t a t i o n , U n i v e r s i t y of O s l o , 1984, 35 pp. 19 J.E. S a t c h e l l , i n A. Burges and F. Raw ( E d s . ) , S o i l B i o l o g y , Academic Press, London and New York, 1967, pp. 259-322. 20 F. Andersson, T. F a g e r s t r o m and S . I . N i l s s o n , i n T.C. Hutchinson and M. Havas ( E d s . ) , Effects o f Acid P r e c i p i t a t i o n on T e r r e s t r i a l Ecosystems, Plenum Press, New York and London, 1980, pp. 319-334. 21 C.O. Tamm, G. Wiklander and B. PopoviE, Water, Air, S o i l P o l l u t i o n , 8 (1977) 75-87. 22 J . Hovland and G. Abrahamsen, I n t e r n a l Report 27, SNSF-project, NISK-As, Norway, 1976, 16 pp. ( I n Norwegian, E n g l i s h summary.) 23 3. Hovland, G. Abrahamsen and G. Ogner, P l a n t and s o i l , 56 (1980) 365-378. 24 T.M. R o b e r t s , T.A. C l a r k e , P. Ineson and T.R. Gray, i n T.C. Hutchinson and M. Havas (Eds. 1, Effects o f Acid P r e c i p i t a t i o n on T e r r e s t r i a l Ecosystems, Plenum Press, New York and London, 1980, pp. 381-393. 25 A.J. F r a n c i s , D. Olson and R. B e r n a t s k y , i n D. Drablnrs and A. T o l l a n ( E d s . ) , E c o l o g i c a l Impact of Acid P r e c i p i t a t i o n , P r o c e e d i n g s o f an I n t . Conf. i n 1980 a t S a n d e f j o r d , Norway, NISK-As, 1980, pp. 166-167. 26 C.O. Tamm and L. H a l l b z c k e n , Water, Air, S o i l P o l l u t i o n ( s u b m i t t e d ) . 4

161

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

A I R QUALITY: D I R E C T EFFECTS OF SO

2

AND NO

X

J. MATERNA F o r e s t r y and Game Management Research I n s t i t u t e

-

Jiloviste

Strnady, CSSR

ABSTRACT Due t o t h e changes i n t h e amount o f

SO emissions and t h e changed 2 f o r t h e i r d i s p e r s i o n d u r i n g t h e l a s t 30-40 Years, t h e character

conditions

o f a i r p o l l u t i o n i n f l u e n c e on analysis

the

forests

t h e r e l a t i o n s between t h e SO

of

has

2 o f s e n s i t i v e t r e e species may be concluded t h a t approximately

15 yg.m

also

changed.

From t h e

concentrations and t h e r e a c t i o n the

-3

threshold

value

is

as l o n g term average. A t t h e p r e v a i l i n g background -3 SO i n l a r g e areas. It i s obvious, t h a t 2 has r e g i o n a l importance. There a r e c e r t a i n d i f f e r e n c e s i n

c o n c e n t r a t i o n s about 15-20 yg.m this

pollutant

the reaction o f dependence

of

sensitive this

tree

reaction

on

species other

p o l l u t a n t s can have a d d i t i v e , more than

on

the

impact

ecological additive

or

especially

conditions. less

than

the

Further additive

effects. INTRODUCTION large

There a r e many t h e o r i e s t o e x p l a i n t h e v i t a l i t y l o s s and injury

in

European f o r e s t s . Even though t h e p r e v a i l i n g cause according t o

t h e general o p i n i o n i s t h e a i r p o l l u t i o n , about

the

processes

a i r pollutants. still

scale

there

is

no

common

agreement

l e a d i n g t o i n j u r y and t h e c o n t r i b u t i o n o f i n d i v i d u a l

Is i s w i t h o u t doubt t h a t t h e d i r e c t impact o f a i r p o l l u t i o n

remains t h e main process causing i n j u r y i n f o r e s t s i n some areas and

t o l o s s e s i n f o r e s t p r o d u c t i o n and i n t h e s o c i a l f u n c t i o n o f main

question

forests.

The

i s what i s t h e e x t e n t o f t h e d i r e c t impact and what are t h e

p o s s i b i l i t i e s t o d i s t i n g u i s h between t h e d i r e c t impact and o t h e r forms

and

ways o f a i r p o l l u t i o n impact i n f o r e s t ecosystems. Also t h e d i r e c t impact o f gaseous parts

of

the

trees

pollutants

on

foliage

p r e c i p i t a t i o n i n v a r i o u s forms such as r a i n , m i s t , rime. O f is

the

and

other

i s considered t o g e t h e r w i t h t h e d i r e c t i n f l u e n c e of main

interest

i n f l u e n c e on c o n i f e r o u s f o r e s t s , where t h e r e are major problems a t

162

t h i s time. THE TREND OF A I R POLLUTION I n some cases i n connection w i t h direct

impact

has

the

"new

damage"

in

view, t h a t t h e d i r e c t impact can be o n l y o f l o c a l character. assumed,

that

there

must

the

F u r t h e r i t was

be an immediate v i s i b l e r e a c t i o n o f f o r e s t s on

elevated concentrations o f a i r pollution. the

forests

been excluded as t h e cause o f i n j u r y from t h e p o i n t o f

Both presumptions

correspond

to

t r e n d o f emissions and a i r p o l l u t i o n sources i n t h e second p a r t o f t h e

n i n e t e e n t h c e n t u r y and i n p a r t t i l l t h e m i d d l e o f development

after

this

this

century.

But

the

t i m e changed markedly t h e c h a r a c t e r and amount o f

emissions and emission sources and t h e t r e n d o f a i r p o l l u t i o n n o t

only

in

amounts

of

t h e surrounding o f t h e i n d u s t r i a l centers. The f i r s t phase

is

characterized

by

relatively

small

p o l l u t a n t s ( m a i n l y SO ) from low stacks, t h e r e f o r e t h e d i s p e r s i o n 2 o f emissions was l i m i t e d and very h i g h s h o r t t i m e c o n c e n t r a t i o n s occurred 5 -3 4 -3 ( w i t h 10 yg.m SO as a max. and 10 yg.m as a mean f o r a 30 min. 2 p e r i o d ) . Neverthless t h e l o n g t e r m average c o u l d remain r e l a t i v e l y low. emitted

The e f f o r t t o reduce t h e ground c o n c e n t r a t i o n s u s i n g

higher stacks, 5 resulted also a t - 10 t SO from 2 one source),in a r e d u c t i o n o f s h o r t term c o n c e n t r a t i o n s and peaks a l s o a t

4 h i g h e r amounts o f emissions (up t o 10

l a r g e d i s t a n c e s from t h e source.

The f u r t h e r i n c r e a s e o f t h e stack h e i g h t s

up t o 300 m and more makes

trend

this

more expresive, The s h o r t t i m e 2 3 -3 c o n c e n t r a t i o n s have been reduced t o 10 10 y g S02.m as a peak and t o 2 0 10 u g as an average over a 30 min. period. The background rose t o 10 1 -3 10 yg.m as l o n g t i m e average. There a r e d i s t i n c t seasonal and y e a r l y

-

f l u c t u a t i o n s i n t h e near ground concentrations. amounts o f e m i t ed SO areas. Comparing same

can

be

2

The

dispersion

the

large

t w i t h t h e t r e n d i n SO

said

about X

emissions, i t i s p r o a b l e t h a t t h e 2 accompanying substances as HF and o r g a n i c

where a s u b s t a n t i a l p a r t i s e m i t t e d from

This development o f emissions and t h e i r d i s p e r s i o n i s for

of

from one source i n f l u e n c e t h e a i r q u a l i t y over l a r g e

substances, b u t n o t f o r NO mobi 1e soures.

-

c h a r a c t e r i s t i c on r e a c t i o n s

t r e e s and f o r e s t ecosystems.

very

small

important

o f vegetation, e s p e c i a l l y o f f o r e s t

163

THE RESPONSE OF VEGETATION The respons o f v e g e t a t i o n t o t h e a i r p o l l u t i o n due t o small

stacks

emissions

from

w i t h l a r g e f l u c t u a t i o n s o f n e a r ground c o n c e n t r a t i o n s can be

a c u t e i n j u r i e s found d u r i n g t h e v e g e t a t i o n p e r i o d . Broad l e a f t r e e s as w e l l as

conifers

suffer

under

gaseous exchange t h e b r o a d

this leaf

influence. trees

can

Due t o a g r e a t e r i n t e n s i t y o f suffer

pollutants

more t h a n e.g. spruce o r pine. The 3 development o f a c u t e i n j u r y a r e c o n c e n t r a t i o n s o f 10

min.

at

from

high

peaks

of

for

the

conditions -3 Mg.m SO

for

30 2 l e a s t a t a h i g h i n t e n s i t y o f p h y s i o l o g i c a l processes i n t h e t r e e s

a t h i g h l i g h t i n t e n s i t i e s and a t a h i g h s o i l and a i r m o i s t u r e c o n t e n t . The a c u t e i n j u r y n e v e r t h e l e s s need n o t t o be v e r y episodes

occur

seldom

and

mostly

at

the

dangerous,

as

the

end o f t h e v e g e t a t i o n p e r i o d

( t e m p e r a t u r e i n v e r s i o n s i n t h e l a t e summer w i t h h i g h peaks o f p o l l u t a n t s ) . To t h e second a r e a concentrations

(up

to

-

air

p o l l u t i o n damage t h e i n f l u e n c e o f low -3 SO as l o n g t e r m average) w i t h seasonal 100 ug.m

and y e a r l y f l u c t u a t i o n s p e r t a i n symptoms

on

the

2

chronic

i n j u r i e s when

no d i s t i n c t

broad l e a f t r e e s occur but a r e v e r y important f o r conifers. I n

b r o a d l e a f t r e e s t h e c h r o n i c i n j u r y i s m o s t l y m a n i f e s t e d by c o l o u r and

premature

leaf

fall

at

the

end

changes

o f t h e vegetation period. Also i n

c o n i f e r s t h e main damage i s connected w i t h a premature n e e d l e f a l l b u t t h i s i s a symptom, w h i c h i s n o t s p e c i f i c enough because such a premature f a l l o f n e e d l e s can a l s o b e a r e s u l t f r o m w a t e r d e f i c i t o r f r o m a s u r p l u s o f

water

i n t h e s o i l , f r o m extreme n u t r i t i o n a l d i s o r d e r o r from f u n g a l a t t a c k . PHYSIOLOGICAL PROCESSES The i n f o r m a t i o n s about t h e i n f l u e n c e o f a i r p o l l u t i o n on p h y s i o l o g i c a l processes can be summarized as f o l l o w s :

-

A f t e r a l a s t i n g impact on t r e e s t h e p h o t o s y n t h e s i s i s m o s t l y l i m i t e d , a s h o r t t e r m i n f l u e n c e , however ,can s t i m u l a t e t h e process. There i s a d i s t i n c t i n f l u e n c e on water regime o f t h e t r e e s , b u t t h i s i s n o t an u n i f o r m t r e n d . Dependent on o u t s i d e c o n d i t i o n s ,

-

s t i m u l a t i o n o r d e p r e s s i o n o f t r a n s p i r a t i o n can occur. There a r e d i s t i n c t changes i n m i n e r a l n u t r i t i o n o f t r e e s . An i n c r e a s e o f s u l f u r c o n t e n t i n t h e needles i s m o s t l y accompanied

-

w i t h an i n c r e a s e o f k a l i u m , c a l c i u m o r magnesium c o n t e n t . There a r e d i s t i n c t changes i n t h e amount o f o r g a n i c c o n s t i t u e n t s

164

( s t a r c h , sugar, aminoacids). MECHANISMS OF

INJURY

The changes i n t h e

physiological

processes

are

manifested

by

the

f o l l o w i n g disturbances:

-

-

Accelerated senescence. This i s shown by premature l e a f f a l l and t h e increase o f s i l i c i u m a c i d i n t h e leaves. The " w i n t e r i n j u r y ' ' o f c o n i f e r s . The absorption o f SO t h e needles o f c o n i f e r s goes on a l s o i n winter.

into 2 The increased

s e n s i t i v i t y t o f r o s t can occur i n s t r o n g w i n t e r s o r a f t e r a sharp drop o f temperature.

Very l a r g e was i n j u r y i n European

f o r e s t s due t o a temperature drop i n t h e l a s t days o f 1978. The needles became r e d and i n t h e s p r i n g a p a r t o f buds was k i l l e d and many t r e e s died. A second example o f w i n t e r i n f l u e n c e i s an i n j u r y t h a t developes i n l a t e w i n t e r , when t h e s o i l i s s t i l l f r o z e n and s t r o n g r a d i a t i o n i n f l u e n c e s t h e t r e e s . A disturbance i n

-

t h e r e g u l a t i o n a b i l i t y o f stomata i s a cause o f needle damage. There i s evidence t h a t f o r t h e l i f e o f t h e t r e e s a l s o t h e d i s t u r b a n c e s i n i n t e r n a l r e l a t i o n s between t h e crown and t h e r o o t s can be o f importance. A d i r e c t impact o f SO

can reduce 2 t h e development o f t h e r o o t s more than t h e development o f t h e crown and a l s o t h e r e d u c t i o n o f and changes i n mycorrhiza can decrease t h e v i t a l i t y o f trees. ECOLOGICAL DEPENDENCES forests

One o f t h e c h a r a c t e r i s t i c f e a t u r e s o f a i r p o l l u t i o n i n j u r y t o its

development

depending

on

t h e r e a r e d i f f e r e n c e s between e.g.

e c o l o g i c a l c o n d i t i o n s . But i n t h i s respect Norway spruce and Scotch pine.

I n spruce f o r e s t s t h e r e i s a c l e a r dependence o f i n j u r y It

is

on

altitude.

n o t p o s s i b l e t o decide t h e most important f a c t o r connected w i t h t h e

a l t i t u d e ; t h e wind v e l o c i t y , t h e i n s o l a t i o n , t h e

temperature,

or s t i l l

o t h e r f a c t o r s . But i t i s obvious, t h a t t h e wind frequency and v e l o c i t y i s a v e r y i m p o r t a n t f a c t o r . Standson exposed s i t e s , mountain r i d g e s edges a r e e a r l i e r damaged as a r e o t h e r p a r t s o f t h e forests.

and

stand

165

A dependence o f t h e i n t e n s i t y of t h e i n j u r y water

content

and

on

mineral

and

its

proven. The dynamic of i n j u r y on o l i g o t r o p h bogs and v e r y accelerated.

In

stands

on

moist

soils

is

p i n e s t a n d s t h e r e i s a c l e a r n e g a t i v e c o r r e l a t i o n between

t h e i n t e n s i t y o f damage and t h e s o i l f e r t i l i t y . these

development

n u t r i e n t r e s e r v e s i n t h e s o i l has a l s o be

can

give

v e r y good r e s u l t s

Therefore f e r t i l i z a t i o n i n

i n i n c r e a s i n g t h e v i t a l i t y and

resistance o f t h e pine forests. Very i m p o r t a n t i s t h e i n f l u e n c e o f f a c t o r " t i m e " i n influence

of

ecological

factors.

For

assessment

relation

tb

the

and e v a l u a t i o n o f a i r

p o l l u t i o n i n f l u e n c e i t i s necessary t o d i s t i n g u i s h :

-

t h e t i m e between t h e s t a r t o f t h e i n c r e a s e o f a i r p o l l u t i o n l e v e l

-

t h e t i m e between t h e b e g i n n i n g o f a i r p o l l u t i o n e f f e c t s and

and t h e occurence o f f i r s t v i s i b l e symptoms d e s i n t e g r a t i o n o f t h e f o r e s t s t a n d as a whole.

I f we summarize t h e r e s u l t s o f s t u d i e s a b o u t t h e and

the

measurements

dispersion

of

emissions

o f n e a r ground c o n c e n t r a t i o n s o f SO ,it i s obvious 2 can be v e r y l o n g and t h e occurrence

t h a t t h e time o f "latent" e f f e c t visible

symptoms

can

be

changed

by

r e l a t i v e l y h i g h mean c o n c e n t r a t i o n s o f SO

other

2

stress

factors.

t h e t i m e between

Also

the

at

beginning

o f a i r p o l l u t i o n e f f e c t s and t h e f i r s t v i s i b l e symptoms can be some y e a r s . The speed o f damage development can be v e r y d i f f e r e n t . We have f o r e s t s d i s t i n c t symptoms o f i n j u r y where d u r i n g t h e l a s t 30 y e a r s t h e damage

with

has n o t c l e a r l y changed and where i t i s reach

their

normal

cutting

possible

that

these

stands

can

age. But t h i s i s t h e case o f f o r e s t s growing

under f a v o u r a b l e c o n d i t i o n s . Under p r e s e n t a i r p o l l u t i o n c o n d i t i o n s a r a p i d development o f t h e damage o c c u r s w i t h u n f a v o u r a b l e e c o l o g i c a l c o n d i t i o n s o r other stress factors. SO

2

CONCENTRATIONS AND THE EFFECTS ON FORESTS The r e a c t i o n o f s t a n d s o f s e n s i t i v e c o n i f e r o u s t r e e s p e c i e s t o t h e SO

pollution

shows,

2 t h a t it i s not possible t o characterise the relationship

without reference t o other ecological factors. There a r e v a r i o u s p o s s i b i l i l i t i e s t o pollution

concentration.

express

F o r p o l l u t a n t s such as SO

c o n c e n t r a t i o n seems t o be a c o n v e n i e n t way. The importance:

the

intensity

of

air

t h e a r i t h m e t i c a l mean 2' f o l l o w i n g values are o f

166

-

t h e a i r p o l l u t i o n l e v e l a t which no respons i s o c c u r r i n g t h e t h r e s h o l d

-

t h e r e l a t i o n s h i p between t h e average c o n c e n t r a t i o n and t h e r e a c t i o n o f

value f o r e s t stands F o r f o r e s t stands i t i s obvious, t h a t i t i s n o t p o s s i b l e t o g a i n answers on t h e s e r e l a t i o n s under l a b o r a t o r y c o n d i t i o n s , Only l o n g l a s t i n g experiments can b r i n g r e s u l t s .

A convenient expression of t h e r e l a t i o n between t h e c o n c e n t r a t i o n o f a certain

pollutant

and i t s e f f e c t i s t h e t i m e between t h e beginning o f t h e

e f f e c t and t h e d e s i n t e g r a t i o n o f t h e stand ( i n t e n s i v e m o r t a l l t y

and t h e

ioss

o f stand structure). From t h e e v a l u a t i o n of r e s u l t s c o n c e n t r a t i o n measurements periods

simultaneously

with

the

over

long

assessment o f f o r e s t stand i n j u r y i t i s

p o s s i b l e t o deduce t h a t : I n spruce f o r e s t s a t h i g h e r e l e v a t i o n s e f f e c t s o f already

extreme e x t e r n a l c o n d i t i o n s a t t h i s p o l l u t i o n develop

air

pollution

be seen a t l o n g e r t e r m mean c o n c e n t r a t i o n s o f 20 yg.m and

an increased m o r t a l i t y

level,

3

serious

SO

2' damage

can Under

Table 1 The t i m e between t h e b e g i n n i n g o f a i r p o l l u t i o n e f f e c t s and t h e d e s i n t e g r a t i o n o f Norway spruce stands ( i n y e a r s ) SO

concentration

2

ug.m

-3

h e i g h t above sea l e v e l ( i n m)

up t o 600

600-900

900-1050

h i g h e r then 1050

20 20

30 50 70 90+

-

30 50

50

70

40

90

30 20

30

-

60

-

40

-

20

-

10

-

50

30

can

occurs (Materna 1982, Wentzel 1982).

30

20

10

20 15

40

20

167

I n stands of w h i t e fir, t h e t h r e s h o l d value i s lower and already 15 -3 SO as a l o n g term average can cause serious i n j u r i e s . ug.m 2 I n t h e p i n e f o r e s t s v i s i b l e symptoms o f i n j u r y i n o l d e r stands appear -3 a f t e r some y e a r s w i t h 25 30 ug.m , a t extreme e x t e r n a l c o n d i t i o n s -3 SO 25 ug.m A d e s i n t e g r a t i o n o f stands r e s u l t s from long already a t 15 2' -3 t e r m c o n c e n t r a t i o n s o f 70 80 Ug.m (Huttunen 1980, Matterna 1981).

-

-

.

-

I f we compare these f i g u r e s with t h e background concentrations o f

in

large

aeras

of

Europe,

it

is

obvious,

consider t h e d i r e c t impact o f SO from t h e SO

as a l o c a l problem, b u t as i t i s 2 trends, t h e d i r e c t impact has over-regional importance.

forests

regions

2 Dose-effect r e l a t i o n s h i p s a r e deduced mainly from measurements i n

in

combustion

where

processes.

physiologicaly

the

air

pollution

SO

2 t h a t i t i s not p o s s i b l e t o

is

seen the

caused mainly through

SO predominates b u t i s n o t the single 2 substance. On t h e b a s i s o f l e a f a n a l y s i s i t i s

The

relevant

p o s s i b l e t o exclude t h e i n f l u e n c e o f HF, b u t n o t t h e i n f l u e n c e o f

nitrogen

oxides. The c o n c e n t r a t i o n s o f NO

i n t h e f o r e s t s we have measured are between 2 60 -100 % of t h e c o n c e n t r a t i o n s o f SO This can be one reason t h a t t h e r e 2' was a s t r o n g c o r r e l a t i o n between t h e S and N c o n c e n t r a t i o n s i n t h e spruce needles

in

stands

with

various

l e v e l s o f a i r p o l l u t i o n (Materna 1981).

Another p o s s i b i l i t y t o e x p l a i n t h i s f a c t i s t h a t t h e i n c r e a s i n g depends on t h e i n f l u e n c e o f SO

2 It i s n o t p o s s i b l e t o s i n g l e o u t t h e e f f e c t of

there

is

only

a

N content

(Materna 1972).

very l i m i t e d data base on t h e NO

NO on f o r e s t t r e e s , as X

X

e f f e c t s . From various

r e s u l t s i t i s p o s s i b l e t o deduce t h a t t h e t o x i c i t y o f NO

X

is

substancially

( T a y l o r e t a l l . 1975, Mooi, 1983, Yang e t a l l 1983). It i s 2 n o t probable t h a t t h e present concentrations o f NO w i l l cause i n j u r y t o 2 f o r e s t stands.

lower t h a n SO

This does n o t exclude t h e p o s s i b i l i t y o f s y n e r g i s t i c with

SO

that

a

or

with

other

2 r e s u l t s o f a study w i t h v a r i o u s clones o f combination

of

effects

of

NO

X

c o n s t i t u e n t s o f p o l l u t e d a i r . AS an example the

SO

w i t h NO

white

pine

have

demonstrated

depending on e x t e r n a l c o n d i t i o n s can

2 2 have an a d d i t i v e , more than a d d i t i v e o r l e s s than a d d i t i v e e f f e c t .

Beside t h e d i r e c t i n f l u e n c e o f gaseous p o l l u t a n t s i t i s p o s s i b l e t o consider t h e d i r e c t i n f l u e n c e of p r e c i p i t a t i o n w i t h v a r y i n g chemical composition.

168

R e s u l t s o f i n t e n s i v e r a i n f a l l s t u d i e s a r e a v a i b l e and a l s o t h e effects

of

the

polluted

rain

were

studied.

p o s s i b l e t o deduce t h a t o n l y p r e c i p i t a t i o n w i t h a pH below effects.

Such

acidity

occurs

only

3

shows

In t h i s

exceptionaly.

direct

these studies i t i s

From

clear

respect

an

i n c r e a s e d danger f o r f o r e s t stands i s due t o t h e f a c t , t h a t h i g h amounts o f condensation

nuclei

i n t h e atmospere i n c r e a s e t h e f r e q u e n c y and i n t e n s i t y

o f r i m e w i t h h i g h c o n c e n t r a t i o n s p o l l u t a n t s . T h i s can

cause

n e c r o s i s of t h e

n e e d l e s d u r i n g thawing. IMPACT OF AMMONIA Due t o r e l a t i v e l y (Buijsman

high

amounts

emitted

l o c a l problem o n l y . Close t o t h e sources i n the foliage o f trees 2

increase

in

some

areas

of

Europe

a l l . 1985) i t seems t h a t ammonia must n o t be c o n s i d e r e d as a

et

-

the

concentrations

of

nitrogen

3 t i m e s i n comparison w i t h t h e normal

l e v e l and t h e c o n c e n t r a t i o n o f i n o r g a n i c n i t r o g e n i n t h e

leaves

increases

even more. A f t e r t h e i m p a c t t h e c o n c e n t r a t i o n o f c h l o r o p h y l l i n c r e a s e s , t h e imbalance i n n u t r i t i o n causes a premature relatively

high

threshold

needle

v a l u e , p r o b a b l y a t 10

fall.

2

-

l i k e l y , t h a t t h e d i r e c t impact o f ammonia w i 1 become

With respect t o 3 -3 10 Ug.m , i t i s not

a r e g i o n a l problem.

DIRECT AND INDIRECT IMPACTS The r e a c t i o n of

the

trees

to

d rect

the

change

in

the

mineral

n u t r i t i o n l e v e l , draws t h e a t t e n t i o n on t h e p o s s i b i l i t y o f i n c r e a s e d danger t o stands i n which t h e m i n e r a l n u t r i t i o n i s u n f a v o u r a b l y i n f l u e n c e d by s o i l changes

caused by a c i d d e p o s i t i o n . It i s p o s s i b l e t o p r o v e a d e t e r i o r a t i o n

o f n u t r i t i o n w i t h Mg, sensitivity

K, Ca on r e g i o n a l scale. Such changes

increase

the

f o r e s t s t o d i r e c t impact o f p o l l u t a n t s and t h e r e f o r e i t i s

of

p o s s i b l e t h a t a c o m b i n a t i o n o f d i r e c t and i n d i r e c t impact can i n f l u e n c e t h e f o r e s t s i n v e r y l a r g e areas. It i s p o s s i b l e t o use l e a f a n a l y s i s t o g i v e e v i d e n c e o f d i r e c t

of

SO

HF, HC1 i f t h e y a r e o c c u r r i n g i n h i g h e r c o n c e n t r a t i o n s .

2’ a n a l y s i s i s w e l l e v a l u a t e d ( G u d e r i a n 1970),

the

l e v e l o f SO

s p r u c e needles. area

2

influenced

differences a t

impact The l e a f

and i t i s p o s s i b l e t o e s t i m a t e

i n t h e atmosphere f r o m t h e c o n c e n t r a t i o n o f s u l f u r i n t h e

(Materna 1981). Leaf a n a l y s i s i s a l s o used t o by

low

an

increased

concentrations

l e v e l o f SO of

sulfur

detect

the

(Rudolph 1983). The small 2 d i o x i d e are nevertheless

169

difficult

to

prove

and

therefore

i t i s q u e s t i o n a b l e whether w i t h l a r g e

i n d i v i d u a l v a r i a b i l i t y o f s u l f u r c o n t e n t i n t h e needles o f f o r e s t t r e e s , i t i s p o s s i b l e t o use t h i s method w i t h success o v e r l a r g e r areas. For n i t r o g e n o x i d e s i t i s o n l y o c c a s i o n a l l y , the

occurrance

of

presence o f NO; leaf

higher

concentrations,

for a

possible

i n t h e f o l i a g e o f spruce and p i n e .

short to

time

after

demonstrate t h e

I n t h e f o l i a g e o f broad

t r e e s these i s normaly a r e l a t i v e h i g h content o f n i t r a t e s detectable

and i t i s n o t p o s s i b l e t o d i s t i n g u i s h t h e i n c r e a s e due t o p o l l u t i o n . The

direct

impact

of

SO

a l o n e and i n c o m b i n a t i o n w i t h o t h e r 2 p o l l u t a n t s decreases t h e i n c r e m e n t o f f o r e s t t r e e s , i n c r e a s e s t h e m o r t a l i t y i n f o r e s t s and has an u n f a v o u r a b l e e f f e c t on t h e q u a l i t y of wood produced. I m p o r t a n t i s a l s o t h e decrease i n t h e r e s i s t a n c e o f f o r e s t

-

further stress factors

stands

to

a b i o t i c as w e l l as i n s e c t s and f u n g i .

For t h e f u t u r e o f t h e f o r e s t s

the

reduction

of

fertility

and

the

impoverishment o f s p e c i e s i s v e r y dangerous. Extremely endangered a r e t h e f o r e s t s i n extreme especially

mountain

forests.

t h e i r social functions.

This

is

climatic

conditions,

a l s o very important i n respect t o

It i s p o s s i b l e t o observe changes i n w a t e r f l o w and

w a t e r q u a l i t y i n damaged f o r e s t e d watersheds.

CONC LUS I O N S A t t h e p r e s e n t l e v e l o f a i r p o l l l u t i o n on a r e g i o n a l s c a l e , t h e d i r e c t impact

of

air

pollution

on

f o r e s t s has a l s o a r e g i o n a l c h a r a c t e r .

f o r e s t s a r e e f f e c t e d by s u l f u r d i o x i d e

and

other

effects

the

information

of

some

of

the

pollutants

pollutants. is

The

About

the

very l i m i t e d .

I n s u f f i c i e n t i s a l s o t h e i n f o r m a t i o n about t h e a i r p o l l u t i o n c o n c e n t r a t i o n s i n forests. Very g r e a t i s t h e r i s k due t o t h e l o s s o f v i t a l i t y and resistance

o f forests t o other stress factors.

the

decreased

E s p e c i a l l y extreme c l i m a t i c

c o n d i t i o n s can cause a s i g n i f i c a n t i n c r e a s e o f i n j u r i e s i n l a r g e areas.

A further threat i s consequence

of

soil

the

changes

disorder due

to

in

the

acid

mineral

s e n s i t i v i t y o f weakened f o r e s t t r e e s p e c i e s t o t h e p o l 1u t i o n .

nutrition

as

a

d e p o s i t i o n and t h e i n c r e a s e d direct

impact

of

air

170

REFERENCES

1

E. Buijsman, J.F.M.

2

S. Huttunen,

Maas and W.A.H.

Asman, Ammonia e m i s s i o n i n

-

1985, R 85

Europe, I n s t . M e t e o r o l . Oceanogr.

2

D i s p e r s i o n and e f f e c t s o f a i r borne p o l l u t a n t s on

f o r e s t environment, Research r e p o r t 1980, 140 pp. Guderian, Z t s c h r .

P f l a n z e n k r a n k h e i t e n u. P f l a n z e n s c h u t z 77 /1970/

3

R.

4

J. Materna, E i n f l u s s n i e d r i g e r Schwefeldioxidkonzentrationen a u f d i e F i c h t e , M i t t . F o r s t l . Bundes Versuchsanst. Wien, 97,

-

1972, 219

232 12, 1981, 137

5

J. Materna, Comm. I n s t . F o r e s t . Cechoslov.

6

J. Materna, L e s n i c t v i 27, 1981, 689

7

J. Materna, A q u i l o , Ser. Bot. 19. 1983, 147

8

J. Mooi, Responses o f some p o p l a r s p e c i e s t o m i x t u r e s o f SO

2’ 196

NO

2

and 0

3’

Aquilo,

9

E. Rudolph, A q u i l a ,

10

O.C.

T a y l o r , C.R.

Ser. Bot.

- 698

-

-

118

Tingey and R.A.

R e i n e r t , Oxides

o f n i t r o g e n i n Responses o f p l a n t s t o a i r p o l l u t i o n ed. J.B. and T.T.

11 K.F.

Kozlowski, Acad.

, Maximale

146

156

19, 1983, 189

Ser. Bot. 19, 1983, 105

Thompson, D.T.

-

-

Mudd

Press New York 1975 383 pp.

SO

K o n z e n t r a t i o n s w e r t e zum Schutze 2 d e r W i l d e r , A q u i l o , 19, 1983, 167 - 177

12

J.S. 406

Wentzel

-

Yang, J.M.

418.

S k e l l y , B.I.

Chevone, A q u i l o , Ser. Bot. 19, 1983,

T. Schneider (Editor)/Acidification and its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

171

STUDIES ON NORWAY SPRUCE (PICEA ABIES KARST.) IN DAMAGED FOREST STANDS AND IN CLIMATIC CHAMBERS EXPERIMENTS K. VOGELSl, R. GUDERIAN' and G. MASUCH'

' I n s t i t u t e of Applied Botany, University, P.O.Box 103 764, D-4300 Essen 1 (FRG) 'Institute

of Applied Botany, University, P.O.Box 103 764, D-4300 Essen 1 (FRG)

3Department of Chemistry, University, P.O.Box 1631, D-4790 Paderborn 1 (FRG)

ABSTRACT I f the monitored a i r pollution values are compared with the a i r quality c r i t e r i a i t becomes apparent that in many parts of Europe high concentrations of ozone, extremely risky t o vegetation, are formed in the summer months (May t o September) with t h e i r high i n t e n s i t i e s of solar i r r a d i t i o n . After 12 weeks of experimental exposure t o 194 pg 03/m 3 ,spruce clone needles exhibited increased i n t e r c e l l u l a r areas associated with increased internal surfaces and raised internal/external surface quotients i f compared to the reference trees. 3 After exposure t o 292 pg S02/m over the same period, however, the i n t e r c e l l u l a r system and both the other values were reduced. The histological changes of the Black Forest spruce t r e e s corresponded t o the experimentally ozone-induced ones whereas the changes of t i s s u e of the Fichtel Gebirge samples were similar t o those recognized a f t e r experimental SO2 exposure. Both the needles of the samples exposed t o e i t h e r O3 o r SO2 and the needles o f the severely damaged f i e l d study items exhibited reductions of transpiration and water potential as well as reduced photosynthetic r a t e s ; simultaneously the osmotic potentials of a l l samples were raised due t o the raised t o t a l sugar contents. Despite of comparatively lower contents of the needles, leaching experiments with Black Forest needles produced higher magnesium and calcium leaching rates than the corresponding experiments w i t h Fichtel Gebirge needles. That the sulfur contents of the Black Forest needles were significantly lower than those of the Fichtel Gebirge items r e f l e c t s the difference in SO2 concentrations the two s i t e s are exposed t o .

INTRODUCTION I t i s widely held t h a t ozone i s a major damage inducing cause o f the present f o r e s t decline in the Federal Republic of Germany. However, given the a i r pollution conditions with long-term exposures t o relatively low concentrations and

172

with various phytotoxic components occuring simultaneously, i t i s rather d i f f i c u l t t o prove the causes d i r e c t l y . That i s why d i f f e r e n t methods have t o be applied t o countercheck the diagnosis. I n the f i r s t p a r t of the following paper the ozone - induced risk f o r vegetation will be outlined by comparing the monitored rates of a i r pollution with the a priori knowledge derived from doseresponse studies. I n the second part r e s u l t s of a s t i l l progressing programme on the causes of the present f o r e s t damages are reported comparing the results of experimental exposures to ozone ( 0 3 ) and s u l f u r dioxide (SO2), singly and in combination, w i t h the responses to a i r pollution exhibited by damaged spruce stands in the Black Forest and in the Fichtel Gebirge. MONITORED AIR POLLUTION VALUES AND AIR QUALITY CRITERIA FOR OZONE IN COMPARISON Based on the analysis and evaluation of the world-wide observed quantitative relations between the ozone concentrations of the a i r and the e f f e c t s on plants the following a i r quality c r i t e r i a were developed.

Table 1. Proposed maximum acceptable ozone concentrations f o r protection of vegetation (1) Exposure Duration Sensitive h pg~m3 300 0.5 150 1.0 120 2.0 100 4.0 ~~~~~~

Resistance level Intermediate PPm 0.150 0.075 0.060

Fg~m3 500 350 250 200

0.050 ~

~

~

~

~

PPm 0.25 0.18 0.13 0.10

Less sensitive

Wm3

1.000 500 400 350

PPm 0.50 0.25 0.20 0.18

~

I f these exposure-duration patterns a r e observed most plant species should be protected from acute damaging e f f e c t s of ozone as single component. W i t h longterm exposures, however, even lower concentratims of ozone may damage plants as the r e s u l t s from the National Crop Loss Assessment Network (NCLAN) of the United States have shown ( 2 ) . Yield reductions of 10 per cent were observed in sensitive plant species a t seasonal 7h/day mean ozone concentrations of only 0.028 t o 0.033 ppm. Accordingly, even a mean concentration of 0.04 ppm during the growth period must be regarded as a potential danger t o sensitive agricultural and horticultural plants ( 3 ) ; and perennial plants should be particul a r l y affected because in the course of time subtle e f f e c t s not onlyadd u p t o s i g n i f i c a n t growth reductions, they also reduce the resistance of the plants to other s t r e s s factors. Other phytotoxic components, such as sulfur dioxide, nitrogen dioxide and acidic precipitation occuring simultaneously are to

173 increase t h i s danger even more ( 4 ) .

A i r analyses c a r r i e d o u t a t many places,

p a r t i c u l a r l y i n the l a s t two

decades, agree on t h e f a c t t h a t i n Europa "anthropogenic" ozone and o t h e r photooxidants a r e formed m a i n l y d u r i n g t h e summer months (May t o September) w i t h t h e i r h i g h i n t e n s i t i e s o f s o l a r i r r a d i a t i o n ( 5 ) . I f t h e monitored a i r p o l l u t i o n values a r e compared t o t h e a i r q u a l i t y c r i t e r i a mentioned above i t has t o be recognized t h a t t h e i n d u s t r i a l conurbations, h e a v i l y a f f e c t e d by t h e precursors n i t r o g e n d i o x i d e and r e a c t i v e hydrocarbons, e x h i b i t t h e h i g h e s t peak concentrat i o n s up t o occasional 1/2 h-concentrations o f more than 0.20 ppm. I n these areas t h e s h o r t - t e r m l e v e l s as shown i n t a b l e 1 are f r e q u e n t l y exceeded and acute damaging e f f e c t s have consequently t o be expected, whereas i n r u r a l p e r i pheral areas, and p a r t i c u l a r l y a t h i g h e r a l t i t u d e s i n t h e German mountains, medium long-term c o n c e n t r a t i o n s were measured t h a t very l i k e l y w i l l cause c h r o n i c and s u b t l e e f f e c t s . MATERIAL AND METHODS The g e o b i o l o g i c a l s t u d i e s presented here were conducted a t 40 t o 60-yearso l d spruce t r e e s i n b o t h t h e F i c h t e l Gebirge (Schneeberg, 1000 m above sea l e v e l ) and t h e southern Black F o r e s t (Belchen, 1050 m above sea l e v e l ) i n May/ June, September and December 1985. At these s i t e s t h e c o n d i t i o n s o f a i r p o l l u t i o n l o a d v a r y remarkably: whereas t h e v e g e t a t i o n o f the southern Black F o r e s t i s endangered p a r t i c u l a r l y by h i g h ozone concentrations, h i g h S02-concentration c h a r a c t e r i z e the c o n d i t i o n s i n t h e F i c h t e l Gebirge ( 6 ) . The t e s t t r e e s were s i t u a t e d i n t h e v i c i n i t y o f m o n i t o r i n g s t a t i o n s a t which continuous measurements o f a c i d i c p r e c i p i t a t i o n s , SO2, O3 and NOx a r e c a r r i e d o u t . With t h e experiments progressing, t h e b i o l o g i c a l r e s u l t s w i l l be shown a g a i n s t the chemicop h y s i c a l values o f t h e a i r analyses. Both an apparently h e a l t h y o r o n l y s l i g h t l y damaged spruce t r e e (damage c l a s s 0 ) and a neighbouring damaged t r e e damage c l a s s 2 t o 3

-

-

were s e l e c t e d as t e s t items. The t e s t needles were

sampled from the m i d d l e crown, 10 t o 14

m above ground l e v e l .

I n t h e course o f t h e c l i m a t i c chamber experiments, t h e equipments o f which

have a l r e a d y been described (7, 8) 3-year-old spruce clones were, s i n g l y o r

3

i n combination, exposed t o s u l f u r d i o x i d e (292 pg/m f 15 p g ) and ozone (194 3 pg/m f 15 p g ) f o r 12 weeks. Both t h e c l i m a t i c chamber experiments and the geob i o l o g i c a l s t u d i e s i n c l u d e d (apparent) photosynthesis and r e s p i r a t i o n measurements u s i n q a c u v e t t e w i t h a O2 e l e c t r o d e (Hansatech). The l i g h t energy was 300

pE/m 2/sec. The t o t a l s u l f u r content was determined w i t h a Fischer-S-analyzer (model 475), w i t h h i g h temperature p i p e s t i l l s , t h e Mg- and Ca-contents, b o t h i n t h e needles and i n the l e a c h i n g s o l u t i o n s , were AAS-measured. The

spruce t w i g s were l a i d i n t o d e s t i l l e d water f o r 4 days b e f o r e c a r r y i n g o u t t h e l e a c h i n g measurements. The c h l o r o p h y l l content was measured p h o t o m e t r i c l y

174

( 9 ) , the Anthron method (10) was used t o determine the total sugar content. To prepare f o r the histological analyses needle pieces, fixed in potassium

bichromate - Os04, were embedded in styrol-methacrylate and contrasted by uranyl acetate and lead c i t r a t e . The samples were analysed by means of a transmission electron microscope Hitachi H 300. For the quantitative histological interpretation 10 sections per sample were selected. HISTOLOGICAL AND CYTOLOGICAL ANALYSES In the quantative approach t o the histological analysis of the climatic chamber experiments, spruce needles revealed differences in the effects of s u l f u r dioxide and ozone. In comparison to the control items an enlarged int e r c e l l u l a r area of the primary needles ( F i g . 1A) could be recognized a f t e r O3 exposure, associated with an enlarged internal surface and consequently a raised internal/external surface quotient (Fig. 1 B ) . Exposures t o SO2 caused the opposite response; both the i n t e r c e l l u l a r system and the internal surface were reduced, and the internal/external surface quotient had decreased. Combined exposures to O3 a n d SO2 caused no significant changes o f the relative i n t e r c e l l u l a r area,allowing the conclusion t h a t opposing effects can neutral i z e each other. The internal/external r a t i o , however, was increased, corresponding to the value a f t e r O3 exposure. Comparing these r e s u l t s to those of t h e geobiological studies (Fig. 2 ) , the 1- and 2-years-old needles of the damaged Black Forest spruce t r e e exhibit the f u l l range of characteristical responses t o 03; both the i n t e r c e l l u l a r system and the internal surface were enlarged and the internal/external surface quotient was increased. I n the Fichtel Gebirge, however, the opposite results were t o be recognized. With a s l i g h t decrease of the i n t e r c e l l u l a r area (Fig 2A) b o t h the internal surface and consequently the internal/external surface quotient are s i g n i f i c a n t l y reduced (Fig. 2B). Ultrastructural analyses revealed a wide-ranging disintegration of the damaged Black Forest t r e e chloroplasts. Compared t o the reference t r e e the grana were reduced in number and wider distributed. The granathylakoids tended t o dilation. The amount of translucent plastoglobules was increased. Chlorop l a s t s of the damaged needles have membrane bound vacuoles t h a t develop a l o n g the chloroplasts and between the thylakoid membranes as well. I n stroma the electron translucent plastoglobules increased i n b o t h number and s i z e , compared

t o those in the reference s e r i e s chloroplasts. The chloroplast changes in the needles of the damaged Fichtel Gebirge t r e e corresponded widely t o the Black Forest symptoms of damage. The damaged trees exhibit b o t h a starch congestion a n d an increased tannine accumulation (Fig. 3 ) . The vacuoles are sometimes densely f i l l e d with tannine corpuscles. Large numbers of tannine f i l l e d vesicles can be found in the

175

cytoplasm particularly next t o the vacuole. In addition, tannine corpuscles were exhibited by the needles o f the damaged Fichtel Gebirge t r e e between the cellul a r wall and the plasmalemma and in the i n t e r c e l l u l a r space.

F

L 't 03

UIO

200 3~~

z

.. .. .. ... ... ...;.;,:.

.. .. 2... .. .. .. .. :...::,-. .'..:

: = 4 : ::: *

100

. .::8

2 .

z.

0

-

*

I D

TRANSVERSE SECTBII AREA IIIERCELLULAR

MESDPHYLL CELL MU

AREA

CONTROL

1n 8

mINIERM1SURFACEII]

EXTERMlSURFACE(E]

i-

3

2 1

0

RATIO I I E

Fig. 1. Results of histological studies on 1-year-old spruce needles a f t e r exposure t o O3 and SO2, singly and in combination A. Effects on transverse section area, mesophyll cell area and interc e l l u l a r area; the i n t e r c e l l u l a r area values are given as absolute figures and as percentages o f the mesophyll area

*P

B.

- 0.05**P

-

O.Ol+*.rP

- 0.001

Effects on internal surface ( I ) , external surface ( E ) , and r a t i o ( I / E )

176

-<

BLACK FOREST

e

a!

FlCHTEl GEBIRGE

OWE YEAR NEEOLES

TWO YEAR NEEOLES

ONE YEAR NEEDLES

0

0

TWO YEAR NEEOLES

.. Y

c1

E,

Bw

6w

600

u)o

LW

2w

mo

n

DAM TREE

CONTROL

CONTROL

MM.TREE

TRANSVERSE SECTION dRLd

CONTROL

OAM.TREE

MESOPHYLl CELL AREA

CONTROL

INTERCELLULAR

OAM TREE

O

AREA

B

E

!s

“7

Y

TWO YEAR NEEOLES

N

EL

12

10 0

6 1

2 REFER TREE

OAM TREE

INTERNAL SURFACE[I)

REFER TREE

DAM

TREE

-

REFER TREE

EXTERML SURFACElEl

MM TREE

REFER.TREE

OAM. TREE

RATIO I / E

Fig 2. Results of histological studies on 1-year and 2-year o l d needles of Black Forest and Fichtel Gebirge spruce trees A Effects on transverse section area, mesophyll cell area a n d interc e l l u l a r area; the i n t e r c e l l u l a r area values are given as absolute figures and as percentages of the mesophyll area

* B

P - 0,05

** P - O , O l * U W

P

-

0.001

Effects on internal surface ( I ) , external surface ( E ) , and r a t i o (I/E)

177

F i g . 3. 1 - y e a r - o l d spruce n e e d l e mesophyll c e l l o f a damaged F i c h t e l Gebirge sample - s t a r c h c o n g e s t i o n i n t h e c h l o r o p l a s t s , d i s i n t e g r a t i o n o f t h e t h y l a k o i d s and t a n n i n e a c c u m u l a t i o n i n t h e v a c u o l e

STUDIES ON PHOTOSYNTHESIS, RESPIRATION AND TOTAL CHLOROPHYLL CONTENT Both i n t h e F i c h t e l G e b i r g e and i n t h e B l a c k F o r e s t t h e o n l y

minimal

damaged r e f e r e n c e t r e e s e x h i b i t e d c l e a r l y h i g h e r a p p a r e n t p h o t o s y n t h e t i c r a t e s t h a n t h e t e s t t r e e s w i t h medium t o s e v e r e damages ( F i g . 4A). Even i f t h e photos y n t h e t i c r a t e s o f t h e r e f e r e n c e t r e e s decreased w i t h i n c r e a s i n g n e e d l e ages, t h e y remained on a h i g h l e v e l compared t o t h o s e o f t h e damaged t r e e s . Because t h e r e s p i r a t i o n r a t e s o f t h e r e f e r e n c e t r e e s decreased as w e l l w i t h i n c r e a s i n g age o f t h e needles, a l l n e e d l e ages e x h i b i t e d p o s i t i v e m e t a b o l i c rates. U n l i k e t h e r e f e r e n c e t r e e s , t h e p h o t o s y n t h e t i c r a t e s o f t h e damaged s p r u c e t r e e s decreased d r a s t i c a l l y w i t h i n c r e a s i n g n e e d l e ages; t h e r e s p i r a t i o n however, was s t i m u l a t e d r e m a r k a b l y ( F i g . 4 8 ) . So t h e p r o v i s i o n o f c a r b o h y d r a t e s o f a damaged t r e e i n t h e B l a c k F o r e s t t h a t possessed o n l y 3 n e e d l e ages was

178

=A

2

5

z

REFERENCE TREE

a

10

30

20 10

0

=

YEAR 85

81

83

82

81

83

82

85

81

83

82

B

‘2 5 E % 7,5

50 2,s

0

YEAR 85

C

yE4R 85

85

81

83

82

85

81

83

82

I

81

83

82

F i g . 4. Apparent photosynthesis ( A ) , r e s p i r a t i o n (B) and t o t a l c h l o r o p h y l l c o n t e n t ( C ) o f t h e reference t r e e s and damaged t r e e s i n the Black F o r e s t and i n t h e F i c h t e l Gebirge

179

confined t o the positive photosynthetic rates of only two needle ages. Exhibiting approximately the same concentrations a t both s i t e s , the total chlorophyll content of the reference trees increased markedly with the needle ages (Fig. 4C), whereas the content of the damaged trees decreased rapidly, in the 3-years-old needles t o about 50%, in the 4-years-old needles of the Fichtel Gebirge samples even to a l i t t l e more than one f i f t h of the 1-year-old needle concentration rates. TRANSPIRATION, WATER POTENTIAL AND OSMOTIC POTENTIAL If transpiration rates, water potential and osmotic potential, i . e . the parameters t o determine the water economy, are compared with the individual photosynthetic rates a f t e r experimental O3 and SO2 fumigations, a close connection between the photosynthetic r a t e and the reduction of both transpiration and water potential i s t o be recognized (Fig. 5 ) . Inversely proportional were the changes of the osmotic potentials, t h e i r increases being connected with elevated t o t a l sugar contents.

z?

. r

..c

0

a

0

25

10 15

I0 5 0

Fig. 5. Apparent photosynthesis, t o t a l sugar content and water economy of spruce clones a f t e r exposure t o s u l f u r dioxide and ozone, singly and in combination In general, the same r e s u l t s were provided by the geobiological studies (Fig. 6 , 7 ) . B u t because transpiration and water potential have t o undergo various diurnal changes, a damaged Fichtel Gebirge spruce t r e e exemplifies the diurnal courses of these two c r i t e r i a (Fig. 6 ) . Even i f a t noon s t r e s s time the reference t r e e achieved remarkably higher maximum rates o f b o t h water pot e n t i a l and transpiration than the damaged tree. The f a c t that b o t h spruce trees exhibited similar diurnal courses of the parameters, however,

180 indicated that the damaged t r e e had n o t yet l o s t i t s capacility t o regulate i t s water economy.

w

a

16

TIME 10

12

13

1L

15

16

17

18

19

Fig. 6. Diurnal water economy rates of the reference t r e e and the damaged tree i n the f i c h t e l Gebirge

I

TOTAL SUGAR CONTENT

OSMOTIC POTENTIAL

1

d

El REFERENCE TREE W C E D TREE

2 25

m

15 10

5

8c

0

Fig. 7. Osmotic potential and total sugar content in the pressed sap o f reference t r e e s and damaged t r e e s in the Black Forest and in the Fichtel Gebirge

As under l a b o r a t o r y c o n d i t i o n s t h e damaged t r e e s o f t h e g e o b i o l o g i c a l s t u d i e s revealed e l e v a t e d t o t a l sugar c o n t e n t s and r a i s e d osmotic p o t e n t i a l s ( F i g . 7); w i t h e r i n g had very l i k e l y a l r e a d y begun. Despite t h e e l e v a t e d d r i v i n g p o t e n t i a l s t h e damaged spruce t r e e s were n o t capable t o compensate t h e water d e f i c i e n c y any l o n g e r . STUDIES ON MINERAL CONTENTS Analyzing t h e calcium and magnesium c o n c e n t r a t i o n s o t t h e needles o f b o t h t h e r e f e r e n c e t r e e s and t h e damaged t r e e s (Tables 2 and 3 ) , we found t h a t :

-

-

the F i c h t e l Gebirge t r e e s showed higher m i n e r a l contents, t h e contents v a r i e d markedly i n needles o f d i f f e r e n t ages, h i g h seasonal changes i n concentrations a r e e v i d e n t , and t h e needles o f t h e damaged t r e e s had lower o v e r a l l concentrations.

Table 2. Contents and l e a c h i n g r a t e s o f Ca i n spruce needles o f reference (RT) and damaged (DT) t r e e s o f t h e Black F o r e s t and t h e F i c h t e l Gebirge Mav/June

I

I

SeDtember

December

I

green yellow needles needles 1985

c o n t e n t (mg/g DW) l e a c h i n g (mg/g DW leaching (% o f content)

1.01 0.070 7.0

1.09 0.105 9.6

2.70 3.34 0.400 0.172 14.8 5.1

1.03 0.251 24.3

1.30

0.68

1984

c o n t e n t (mg/g DW) l e a c h i n g (mg/g DW leaching ( % o f content)

2.66 0.017 0.6

1.26 0.012 0.9

4.63 3.27 1.305 0.189 28.2 5.8

1.39 0.157 11.3

1.30 --1)

0.96

1983 1982

c o n t e n t (mg/g DW)

2.65

2.43

c o n t e n t (mg/g DW)

4.54

1.36

1985

c o n t e n t (mg/g DW) l e a c h i n g (mg/g OW 1each ing (% o f content)

2.16 0.024 1.1

1.51 0.080 5.3

4.26 0.039 0.9

3.38 0.052 1.5

1984

c o n t e n t (mg/g DW) l e a c h i n g (mg/g DW leaching ( %o f content)

5.74 0.005 0.1

7.14 0.009 0.1

5.28 0.03C 0.6

6.09 0.045 0.7

--I)

--I)

--I)

R G E

1983

c o n t e n t (mg/g DW)

1982

c o n t e n t (mg/g DW)

l--l)

n o t proved

I

182 Table 3. Contents and l e a c h i n g r a t e s o f Mg i n spruce needles o f reference (RT) and damaged (DT) t r e e s o f t h e B?ack F o r e s t and t h e F i c h t e l Gebirge MaylJune Year

Item

RT

L A C C c o n t e n t (mg/g DW) l e a c h i n g (mg/g DW) leaching ( %o f content)

0.91 0.235 25.9

0.79 0.042 5.3

384

c o n t e n t (mg/g DW) l e a c h i n g (mg/g DW) 1eachi ng ( % o f content)

0.31 0.004 1.3

0.22 0.002 0.9

c o n t e n t (mg/g DW)

382

c o n t e n t (mg/g DW) c

December

T

qz-l-E

il;: ;:1

F O R E S T

985

983

September

0.014

0.161

::i7

0.032

0.158

0.039

0.012

_

I C H T E L 385

c o n t e n t (mg/g DW) l e a c h i n g (mg/g DW) 1eachi ng ( % o f content)

1.03 0.115 11.6

984

c o n t e n t (mg/g DW) l e a c h i n g (mg/g DW) leaching ( % o f content)

0.73

983

c o n t e n t (mg/g DW)

982

c o n t e n t (mg/g DW)

I

G E B I R G E

1.15 0.161 14.0

0.82 0.007 0.9

0.73 0.017 2.3

0.82

0.78

0.81

The t r e e s o f t h e two s i t e s v a r i e d d i s t i n c l y i n t h e supply o f calcium; t h e c a l cium r a t e s o f t h e F i c h t e l Gebirge spruces were approximately t w i c e as h i g h as those o f the Black F o r e s t items. A t b o t h s i t e s t h e calcium r a t e s o f the r e ference t r e e s and o f t h e damaged t r e e s increased w i t h the age o f t h e needles. U n l i k e i s t h e magnesium c o n c e n t r a t i o n s present a c o n t r o v e r s i a l p i c t u r e : i n the Black F o r e s t samples t h e y decreased markedly w i t h i n c r e a s i n g ages o f t h e needles, whereas t h e F i c h t e l Gebirge items showed n o t h i n g b u t a s l i g h t tendency t o decrease. With some exceptions, the lowest concentrations were detected i n December, t h e decrease being more d i s t i n c t i n t h e magnesium contents. Comparing t h e damaged t r e e s and t h e reference trees, p a r t i c u l a r l y the damaged Black F o r e s t samples e x h i b i t e d lower concentrations, and again t h e r e l a t i v e d i f f e r e n c e i n magnesium was g r e a t e r than t h a t o f calcium. J u s t as t h e contents o f the needles, the leaching r a t e s depend t o a h i g h degree on t h e s i t e , t h e age o f the needles and t h e season (Tab. 2, 3 ) . I f the f u l l range o f values o f b o t h years are compared i t can be recognized t h a t o u t o f the

183 Black F o r e s t samples h i g h e r Ca-amounts were washed than o u t of the F i c h t e l Gebirge items; b o t h t h e r a t e s r e l a t i v e t o the needle content

and t h e absolute

r a t e s were h i g h e r . With s i g n i f i c a n t l y lower Ca-contents o f the needles, the conc e n t r a t i o n s washed o u t of t h e Black F o r e s t samples were h i g h e r than those washed o u t o f t h e F i c h t e l Gebirge items. The absolute amounts o f magnesium washed o u t were approximately a l i k e a t b o t h s i t e s , t h e r e l a t i v e l e a c h i n g r a t e s of t h e Black F o r e s t samples, however, were h i g h e r again. Most o f the damaged t r e e s e x h i b i t e d both a b s o l u t e l y and r e l a t i v e l y h i g h e r l e a c h i n g r a t e s than the reference trees, w i t h t h e e x c e p t i o n o f t h e Black F o r e s t reference t r e e and i t s s i g n i f i c a n t l y h i g h e r Ca-leaching r a t e s . I n December no calcium and magnesium concentrations c o u l d be detected i n t h e l e a c h i n g water. E x c l u d i n g t h e 1-year-old needles o f t h e May/June sampling i n the Black Forest, much h i g h e r t o t a l s u l f u r c o n c e n t r a t i o n s were d e t e c t e d i n tne F i c n t e l

tie-

b i r g e samples ( F i g . 8 ) . And i t was here again t h a t the s u l f u r concentrations i n creased w i t h t h e needle ages, whereas i n t h e Black F o r e s t such an increase c o u l d n o t be recognized. Over t h e year, the 2-years-old F i c h t e l Gebirge needles e x h i b i t e d an i n c r e a s e t o a December maximum. In t h e Black F o r e s t the maximum r a t e s were d e t e c t e d i n t h e needles o f t h e developing new sprouts. This r a p i d decrease o f c o n c e n t r a t i o n t a k i n g p l a c e over the y e a r i s very l i k e l y due t o the r a i s e d d r y w e i g h t / f r e s h w e i g h t r a t i o which i t s e l f caused a d i l u t i n g e f f e c t . A l l t h e o t h e r c o n c e n t r a t i o n r a t e s were a t about 0.9 mg/g d r y substance. U n l i k e the Mg and Ca concentrations,

t h e s u l f u r contents o f the damaged t r e e s a t b o t h s i t e s d i d n o t

d i f f e r s i g n i f i c a n t l y from t h a t o f the undamaged t r e e s .

I

-

FICHTELGEBIRGE SEPTEMBER

DECEMBER

; 1-

DECEMBER

U REFERENCE TREE MMtEO TREE

a8

ar, YEAR 0 85

Fig.

a.

55

81

83

82

85

81

T o t a l s u l f u r c o n t e n t i n t h e needles of reference t r e e s and damaged t r e e s i n t h e Black F o r e s t and i n the F i c h t e l Gebirge

184

DISCUSSION With t h e g i v e n long-term exposures t o various p h y t o t o x i c a i r p o l l u t a n t s , the major components o f t h e p r e s e n t f o r e s t d e c l i n e can n o t o n l y be determined by f i e l d s t u d i e s . To countercheck t h e diagnosis by hypothesis t e s t i n g , l a b o r a t o r y experiments under c o n t r o l l e d and r e p r o d u c i b l e c o n d i t i o n s must be added.

I n b o t h c l i m a t i c chambers and small greenhouses, fumigation experiments w i t h l a t e n t and c h r o n i c doses of ozone, s u l f u r d i o x i d e and n i t r o g e n d i o x i d e as w e l l as v a r y i n g n u t r i e n t s u p p l i e s were c a r r i e d o u t i n t h e course o f which m o t t l i n g , chloroses and necroses c o u l d be observed

-

i n j u r y symptoms t h a t were e x h i b i t e d

by t h e damaged f o r e s t stands as w e l l ( 4 ) . Some s i g n i f i c a n t l y s i m i l a r phenomenological, p h y s i o l o g i c a l and h i s t o l o g i c a l / c y t o l o g i c a l changes i n b o t h t h e f u m i g a t i o n experiments spruce clones and t h e spruce t r e e s o f damaged f o r e s t stands c o n f i r m the t h e s i s t h a t i t i s m a i n l y the combination of ozone and s u l f u r d i o x i d e associated w i t h NOx t h a t must be regarded as t h e p r i m a r y and major p r e d i s p o s i n g cause of damage. The damage p a t t e r n s o f the Black F o r e s t being m a i n l y induced by ozone, t h a t o f t h e F i c h t e l Gebirge by s u l f u r d i o x i d e . P a r t i c u l a r l y a f t e r combined exposures t o O3 and SO2, b o t h the f i e l d studies and c l i m a t i c chamber experiments needles e x h i b i t e d h i g h l y hypertrophied Strasburger c e l l s , a reduced phloem and collapses o f phloem elements ( 8 ) . Disi n t e g r a t i o n s o f t h e phloem, p r e v i o u s l y observed by F i n k (11) and Parameswaran

( 1 2 ) , were associated w i t h p a t h o l o g i c a l s t a r c h accumulations i n the c h l o r o p l a s t s and tannine accumulations i n b o t h t h e t r a n s f u s i o n and mesophyll t i s s u e . Despite reduced p h o t o s y n t h e t i c r a t e s and increased r e s p i r a t i o n r a t e s , r a i s e s i n t o t a l sugar c o n t e n t s o f t h e damaged spruce t r e e s a r e observed, i n d i c a t i n g a d i s t u r b e d metabolism o f t h e carbohydrates. P a r t i c u l a r a t t e n t i o n must be given t o the l i m i t e d water economy. Reductions o f t r a n s p i r a t i o n and water p o t e n t i a l as w e l l as r a i s e d osmotic p o t e n t i a l due t o r a i s e d sugar contents were t h e responses o f t h e c l i m a t i c chamber experiments w i t h spruce and of damaged t r e e s i n t h e f i e l d as w e l l . With these d i s turbances o f t h e water economies, which have been detected i n t h e c o u r s e o t o t h e r s t u d i e s as w e l l (13, 14, 15),a premature senescence o f t h e needles and r e s t r i c t e d n u t r i e n t uptake from t h e s o i l must be expected, p a r t i c u l a r l y i t t n e n u t r i e n t supply from t h e s o i l i s l i m i t e d (16, 17) and t h e leaching o f the needles i s increased (18, 19).

A r a i s e d p e r m e a b i l i t y of t h e Black F o r e s t needle-biomembranes has t o be assumed i f , d e s p i t e of comparatively lower contents, the Mg and Ca concentrat i o n s t h a t have been washed o u t a r e higher than those washed o u t o f t h e F i c h t e l Gebirge samples. Due t o t h e s i g n i f i c a n t l y h i g h e r SO2 exposures i n the F i c h t e l Gebirge, t h e washout o f t h e spruce t r e e s " f r e e space" should be r a i s e d i f compared t o t h e Black F o r e s t samples.

185 The e l e v a t e d S02-exposures i n the F i c h t e l Gebirge n o t o n l y caused s u l f u r contents o f the needles t h a t were h i g h e r than those o f t h e Black F o r e s t needles, b u t a l s o changes o f t h e t i s s u e , as c o u l d be observed a f t e r experimental

SO2

exposures. Due t o t h e h i g h e r ozone doses, t h e Black F o r e s t spruce t r e e s e x h i b i t e d an enlarged i n t e r c e l l u l a r system,

an increased i n t e r n a l s u r f a c e and a

r a i s e d i n t e r n a l / e x t e r n a l s u r f a c e q u o t i e n t , c m p a r a b l e t o ozone-induced changes of

t h e t i s s u e as t h q y a r e observed i n t h e c l i m a t i c chamber experiments.

REFERENCES

1 R. Guderian, D.T. Tingey and R. Rabe, E f f e c t s o f photochemical o x i d a n t s on p l a n t s , i n R. Guderian (ed.): A i r p o l l u t i o n by photochemical oxidants. Formation, t r a n s p o r t , c o n t r o l , and e f f e c t s on p l a n t s . E c o l o g i c a l Studies 52, Springer-Verlag, B e r l i n , Heidelberg, New York, Tokyo, 1985a, pp. 126-346. 2 W.W. Heck, W.W. Cure, J.O. Rawlings, L.J. Zaragoza, A.S. Heagle, H.E. Heggestad, R.J. Kohut, L.W. Kress and P.3. Temple, Assessing impact o f ozone t o a g r i c u l t u r a l crops. I . Overview. 11. Crop y i e l d f u n c t i o n and a l t e r n a t i v e exposure s t a t i s t i c s , J . A i r P o l l u t . Contr. Assoc. 34 (1984) 729-735, 810-817. 3 R. Guderian und D.T. Tingey, Notwendigkeit und A b l e i t u n g von Grenzwerten f u r S t i c k s t o f f o x i d e . Forschungsbericht 106 07 055, Umweltbundesamt, B e r l i n 1986. 4 R. Guderian, K. Kuppers und R . Six, Wirkungen von Ozon, Schwefeldioxid und S t i c k s t o f f d i o x i d auf F i c h t e und Pappel b e i u n t e r s c h i e d l i c h e r Versorgung m i t Magnesium und Kalzium sowie a u f d i e B l a t t f l e c h t e Hypogymnia physodes. V D I B e r i c h t e 560 (1985b) 657-701. 5 K.H. Becker, W. F r i c k e , J. Lobe1 and U. Schurath, Formation, t r a n s p o r t and c o n t r o l of photochemical oxidants, i n R. Guderian (ed.), A i r p o l l u t i o n by Dhotochemical oxidants. Formation. t r a n s o o r t . c o n t r o l and e f f e c t s on Dlants. E c o l o g i c a l Studies 52, Springer-Verlag, B e r l i n , Heidelberg, New York,' Tokyo, 1985. O D . 4-126. r r . 6 UBA (Umwel tbundesamt) Hrsg. : Monatsberichte aus dem MeBnetz, B e r l i n 19821985. 7 K. Vogels and G. Masuch, Metabolic and s u b s t r u c t u r a l changes o f bean leaves caused by separate and simultaneous ozone and s u l f u r d i o x i d e exposures. I n proceedings o f an i n t e r n a t i o n a l workshop i n Goteborg, Sweden, February 29 March 2, 1984, Swedish Environmental Research I n s t i t u t e , Goteborg (1984) 128- 144. 8 R. Guderian, K. Vogels and G. Masuch, Comparative p h y s i o l o g i c a l and h i s t o l o g i c a l s t u d i e s on Norway spruce (Picea abies K a r s t . ) by c l i m a t i c chambers experiments and f i e l d s t u d i e s i n damaged f o r e s t stands. 7 t h World Clean A i r Congress & E x h i b i t i o n , Syndney, A u s t r a l i a 25-29 August 1986. 9 D . I . Aron, Copper enzymes i n i s o l a t e d c h l o r o p l a s t s . Polyphenoloxidase i n Beta v u l g a r i s , P l a n t P h y s i o l . 24 (1949) 1-15. 10 L. Steubing, Pflanzenokologisches Praktikum, Verlag Paul Parey, B e r l i n , Heidelberg und Hamburg 1965, pp. 262. 11 S. Fink, H i s t o l o g i s c h e und histochemische Untersuchungen an Nadeln erkrankt e r Tannen und F i c h t e n i m Sudschwarzwald, AFZ 26/27 (1983) 660-663. 12 N. Parameswaran, S. F i n k und W. Liese, F e i n s t r u k t u r e l l e Untersuchungen an Nadeln geschadigter Tannen und F i c h t e n aus Waldschadensgebieten i m Schwarzwald, Eur. J . For. Path. 15 (1985) 168-182. 13 S. Strack und H. Unger, Wassertransport und Wasserumsatze i n kranken und gesunden F i c h t e n , Statusseminar KFA J u l i c h , 2.-4.12. 1985. 14 A. W i l d und J. Bode, Physiologische, biochemische und anatomische Untersuchungen von immissionsbelasteten F i c h t e n verschiedener Standorte. Statusseminar KFA J u l i c h , 2.-4.12. 1985. - - I

186 15 E.D. Schulze, R. Oren, K. Werk, J . Meyer und R. Zimmermann, Kohlenstoff-, Wasser- und Nahrstoffhaushal t von Fichten s t a r k b e l a s t e t e r Hochlagenstando r t e a u f P h y l l i t i n NO-Bayern, Statusseminar KFA J u l i c h , 2.-4.12. 1985. 16 E . Mies und H.W. Z o t t l , Z e i t l i c h e Pinderung d e r C h l o r o p h y l l - und Elementgeh a l t e i n den Nadeln eines g e l b - c h l o r o t i s c h e n Fichtenbestandes, Forstw. Cbl 104 (1985) 1-8. 17 H.W. Z o t t l , Waldschaden und Nahrelementversorgung. Dusseldorfer Geobotanisches Kolloquium 2 (1985) 31-41. 18 6. P r i n z , G.H.M. Krause und H. Stratmann, Waldschaden i n d e r Bundesrepublik Deutschland. L I S - B e r i c h t e 28 (1982) pp. 154. 19 G.H.M. Krause, K.D. Jung und 6. Prinz, E x p e r i m e n t e l l e Untersuchungen z u r Aufklarung der n e u a r t i g e n Waldschaden i n d e r Bundesrepublik Deutschland, VDI-Berichte 560 (1985) 627-656.

.

ACKNOWLEDGEMENTS This study was supported by t h e European Commission P r o j e c t N r . ENV-846-D ( 5 )

T. Schneider (Editor)/Acidi~icationand its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

189

DETERIORATION PROCESSES OF HISTORICAL MONUMENTS D A R I O CAMUFFO

N a t i o n a l R e s e a r c h C o u n c i l , CNR-ICTR,

Padova, I t a l y

ABSTRACT

The problem of t h e conservation of h i s t o r i c a l monuments ( s t a t u e s , columns, a n c i e n t b u i l d i n g s ) r e q u i r e s an a c c u r a t e study of t h e many environmental agents which bring about t h e d e t e r i o r a t i o n process and a f f e c t t h e a c t u a l rate of d e t e r i o r a t i o n . Among t h e most a c t i v e causes of weathering, we can c i t e : ( i ) t h e weakening of t h e o u t e r l a y e r of t h e a r t work, which i s caused by complex microphysical e f f e c t s and i s in particular due t o wtting of the wnumnt ( a comparison between t h e e f f e c t s of rainwater and condensation i s made); ( i i ) t h e chemico-physical a c t i o n of p o l l u t a n t s captured i n both t h e d r y and wet phase. The d e s t r u c t i v e processes depend on many f a c t o r s : t h e p a s t h i s t o r y of t h e monument, t h e c a p t u r e and n a t u r e of t h e p o l l u t a n t s , and t h e frequency of some microclimatic conditions, p a r t i c u l a r l y those supplying t h e water necessary f o r chemical r e a c t i o n s . To t h i s end s t u d i e s of d i u r n a l and seasonal v a r i a t i o n s on t h e monument of both t h e h e a t wave and t h e f l u x e s of moisture and energy are very important. Some of t h e s e processes have been shown with microclimatic s t u d i e s and microphysical i n v e s t i g a t i o n a s s o c i a t e d with mineralogic and chemical analyses of samples of weathered m a t e r i a l . Mathematical models i n some c a s e s ( e s p e c i a l l y f o r s o l a r r a d i a t i o n and temperature) permit physical simulation, r e c o n s t r u c t i o n of p a s t d a t a and extrapolation into the f u t u r e observation of many monuments from d i f f e r e n t epochs, situated a t v a r i o u s sites, g i v e s examples of t h e fundamental processes that are o f t e n associated with, o r masked by, o t h e r e f f e c t s . The main weathering processes are due t o t h e combined a c t i o n of rainwater and atmospheric p o l l u t a n t s ( p a r t i c u l a r l y t h e carbonaceous p a r t i c l e s due t o combustion) deposited on t h e s u r f a c e of t h e monument. The way i n which t h e s u r f a c e is wetted i s very important: i n fact, a s h o r t d r i z z l e can a c t i v a t e t h e d r y d e p o s i t without washing it away, and i n t h i s c a s e t h e pH of r a i n d r o p l e t s i s of secondary importance; on t h e o t h e r hand, showers supply abundant water which favours d i s s o l u t i o n of t h e stone and removal of t h e s o l u t e , r e s u l t i n g i n a thinning of t h e o r i g i n a l rock. Another important f a c t o r is t h e dynamic regime ( i . e . laminar o r t u r b u l e n t ) of t h e water flowing over t h e s u r f a c e of t h e monument. In zones where t h e s u r f a c e of marble o r calcareous monuments is only wetted, but p r o t e c t e d from run-off, black c r u s t s ( c h a r a c t e r i z e d by c r y s t a l s of gypsum and calcite with carbonaceous p a r t i c l e s embedded i n t h e c r u s t s ) a r e formed. Zones subjected t o heavy run-off are a l s o subjected t o a thinning of t h e rock and small authentic calcite c r y s t a l s form t h a t a r e white i n

190

appearance. In the case of relatively unpolluted towns, where marble and limestone sulphation is not the main cause of the deterioration process, biological deterioration mechanisms are often very important, due to the activity of epilithic and endolithic microflora and microfauna.

The case of cussed i n order of q r i m e n t a l and not only an

CAN

particularly precious mortars, i.e. m a l s or frescces, is dist o clarify the thermodynamic mthcd proposed for the analysis campaigns. Finally actions are described that act on the causes the effects.

DETERIORATION BE EXPRESSED IN TERMS OF SULPHUR DIOXIDE LEVELS

OR ACID RAIN ALONE? In

last decade,

the

deterioration definitive of

its

calamity

society,

and

in

is

clear

directly

responsible

monuments

(statues,

of

artistic

heritage

and

the

to

I

the

to atmospheric pollution, but it is

which

or

by-products of our modern

chemical

t h e y a c t on

exactly h o w

ancient

components a r e themost

buildings,

columns,

As the

in

industrialization and urbanization, especially

the

phenomenon pollution

second

world

could

be

and

in

war,

occurred

etc.).

deterioration

both

has

the

monument

increase after

linked

particular

particularly

rate

inestimable

progressive

of many masterpieces. It is clear that the cause

loss

this

not

of

Europe h a s witnesed a

many

ascribed

to

with the general

authors suggested that this the

increasing

rate of air

particular to sulphur dioxide (for an overview

see ref. 1 ) . In the

this hypothesis the deterioration process is mainly due to surface

atmosphere marble

statues

limestone

of

monuments.

sulphur

,

in

would

With

pollutants

processes be

due

particular

catalysts

weathered

of

of

condensation

compounds

presence

kind

by

and

sulphur

action

into

of

sulphuric

removed

(ref.2). to

the

from

the

The corrosion of transformation of

sulphur dioxide in the acid

on

the surface of

this model we would expect to find buildings and in

a

more o r less uniform way, with only one

deterioration crust, thicker or thinner according to the

environmental

aggressivity,

which could then be simply expressed

in

concentration

of

terms

of

pollutants in the atmosphere and

191

time

of

w e t n e s s , the time

monuments

m o r e s e v e r e l y d e t e r i o r a t e d a n d c o v e r e d by a t h i c k e r a n d

continuous

scab

on

the

s i d e , w h i c h i s t h e more humid

northern

a monument, s i m i l a r t o t r e e s c o v e r e d b y moss. T h i s model

of

fails

three

on

points:

correlation

has

pollutants)

concentration

on

is

o n t h e s u r f a c e . A s a c o n s e q u e n c e , we would e x p e c t t o f i n d

present

part

during which and adsorbed film

been

(i)

found

not

one

between

reliable

sulphur

quantitative

dioxide (or other

a n d d a m a g e ; ( i i ) t h e l o c a t i o n of s c a b s

t h e monuments i s n o t i n a c c o r d a n c e w i t h t h i s h y p o t h e s i s ; ( i i i )

on

same

the

non-sulphated

we

monument

can

find

sulphated

areas

and

e x p o s e d t o t h e same c o n c e n t r a t i o n l e v e l s of

areas,

a t m o s p h e r i c p o l l u t a n t s during the same period of wetness. Acid

r a i n was indicated

deterioration out

(see

e.g.

as a n o t h e r

ref.3).

p o s s i b l e c a u s e of s t o n e

Many s t u d i e s h a v e b e e n c a r r i e d I f we o b s e r v e a

i n t h i s d i r e c t i o n with contradictory r e s u l t s .

we

monument, caused

by

rain,

deteriorated run-off.

s e e t h a t , t h e p a r t s more e x p o s e d t o t h e damage

can in

The

those

i.e.

a

different

experiencing

manner

from

run-off,

have

t h o s e p r o t e c t e d from

proposed weathering p r o c e s s h a s , i n p r a c t i c e , t h r e e

steps:

( i ) atmospheric g a s e s d i s s o l v e d i n water form a chemically

active

solution;

t h i s reacts with t h e stone

(ii)

and forms t h e

c r u s t , t r a n s f o r m i n g p a r t o f t h e c a l c i t e o f t h e s t a t u e i n t o gypsum,

is

which away

more

the

crust

material of

the

(ref.5) the

soluble removing

i n water; ( i i i ) t h e n e x t r a i n f a l l washes a

l a y e r of s t o n e ( r e f . 4 ) . The l o s s o f

i s a f u n c t i o n o f b o t h t h e t h e pH, c o n s i d e r e d a s a n i n d e x aggressivity

of r a i n w a t e r , and t h e i n t e n s i t y of r a i n f a l l

w h i c h s u p p l i e s a new u n s a t u r a t e d s o l u t i o n i n c o n t a c t w i t h

surface.

The

process

would

be

more

active

if

the

p r e c i p i t a t i o n o c c u r r e d o n a l r e a d y damp s t o n e . In run-off layer

reality,

on

marble

monuments

the

zones

a r e t h i n n e d . Only r a r e l y d o e s t h e p r e c i p i t a t i o n o f a t h i n

of s p a t i c c a l c i t e o c c u r . Surprising,

considering

above mentioned stew (iii), sulphation is hardly When

experiencing

run-off

Therefore,

one

is

prevented,

must

conclude

sulphation that:

(1)

is

a

the

present.

at its

maximum.

n o t i c e a b l e p a r t of

192

sulphur

compounds

that affect

the stone are airborne

and

deposited

via

dry

deposition processes; (ii) the main action of

the

rainfall

is to thin the stone, but acid rainfall alone

is

acid not

the

sufficient

to explain the formation of one of

by itself

worst kinds of stone deterioration: the formation of the well

known

black

crusts,

essentially composed of gypsum crystals and

soot particles. The

role

of

since

the

still

unsolved.

acid to

problem

rain what

chemical

agents

has

been extensively.studied

first arose, many problems

One

,

however, remain

could suppose that both sulphur dioxide and

are partially responsible for stone deterioration, but extent

it

is

not easy to say. They are only part of a

more complex process. In

the

case of relatively unpolluted towns, where marble and

limestone

sulphation

process,

biological

important.

The

Mediterranean organisms biological

are

by

mechanisms

plant

organisms

may found

be in

very the

blue algae and lichens; and the animal

rotiphera

pollution

activity:

substituted

active

mainly

environmental

not the main cause in the deterioration

deterioration

most

region

are

is

(ref.6

levels

has

epilithic

endolithic

and 7 ) . The increase of

caused

species organisms

a

change

in

the

have been progressively as these are more compa-

tible with the new habitat. Careful

observatioq

of

weathered

monuments

reveals

that

deterioration is not only due to chemical and biological aqents but

is also a function of:

local

microclimatic conditions, of

porosity which continues to increase with exposure (ref. 8 ) and of surface geometry. The surface paper

microclimatic

geometry have not been is

factors

to

emphasize

the

factors (see ref.9 to 1 2 ) and widely studied. The aim of this

influence of these two hardly known

and conclude with a general model on the formation of the

different limestone. the

of

effects

crusts We

problems

and

will

visual

features

of

weathered carbonatic

speak in general in terms of stones, but all

associated

with

the

porosity of limestone

can

193

also

be

extended

made

to

limestone

Mediterranean the

to and

basin,

Gothic,

the

bricks

and mortar.

marble,

from

as

Special

the

main

reference is

monuments of the

the classical Roman and Greek age, to

Renaissance,

the Baroque epochs, are made from

these materials. THE ROLE OF THE MAIN MICROCLIMATIC FACTORS Solar between

radiation the

variable stress the

heat

the

and

moisture

exchange

atmosphere and the monument. It is well known that a

input

of

heat

causes thermal gradients and mechanical

inside the monument, which can reach undesired levels near

juncture

imprisoned door

causes

zones,

a

e.g.

legs

of

a

bronze equestrian statue

marble base, or bronze panels nailed onto a

wooden

as

in

the many Gothic and Renaissance buildings. The zones

weakened

by

severe

further

weathering. Broad temperature cycles may

mechanical

stress

may

be

damage, especially when

undesired

hygrometric

effect.

more exposed to the risk of enhance

they are associated

Experimental

with an

field tests on the

seasonal and diurnal environmental cycles combined with mathematical models to describe general problems on specific monuments, have permitted the physical simulation, the reconstruction of data and a prediction for the future, such as in the case of the San Marc0 Horses in Venice or the Trajan and Aurelian Columns in Rome and several other Basilicas (ref. I3 to 21).

Fluxes

of

heat

and

moisture

can

favour

or

oppose

the

deposition

processes of atmospheric pollutants and the adsorption

of

For

gases.

dioxide the

concentration

effects

negligible. only

of

example, in Rome we found that the hourly sulphur

the

of In

one any

has of

a

bi-modal diurnal distribution, but

these

case,

concentration

two

peaks

should be considered

the deposition rate is a function not of pollutants in the atmosphere, but

also of different deposition processes, that are in itself a function of both atmospheric and surface characteristics. Moreover these processes are qenerally unknown. This explains how hazardous it would

be

to

make a correlation between

pollutant

concentration

in

the

atmosphere

and

the

resulting

damage to the stone. The

diurnal thermal cycle of the monument associated with the of

variation

the

environmental

condensation-evaporation turn

depend

soluble

salts

Clearly, of

on

the and

cycles

stone the

specific on

the

of

point

cause

presence the

and

kind of

environmental

air.

i t s i s not correct to consider only the relative humidity

the

surrounding

process.

Less

atmosphere known

external

micropores

humidities

with

variation

of

(according

to

symmetrically. addition

to

cycles occurs

respect

the

much on

to

a

Kelvin

more

frequent

micropores.

at

lower

are

Condensation on

equilibrium

relative

flat

surface,

favoured

vapour

pressure

over

equation)

and

saturation the

in order to make a model of this

but

condensation-evaporation

by the

a meniscus

evaporation

occurs

In the internal micropores condensation depends in the

above

parameters,

on the spatial association,

geometrical

shape and the radii of curvature of the

Evaporation

depends

23).

may

stone surface, which in

temperature,

dew

humidity,

Therefore,

on

the

radius

considering

only

micropores.

of the pore outlet (ref.22, one

waterfront

inside

the

monument

is a very crude approximation of the reality: one should

consider

a

stone,

series

each

one

of

waterfronts

dependent

on

in spatial succession in the and critical values o f the

kind

pores which become filled with water at that depth. Not the

only direct solar radiation causes spatial differences in

surface

temperature; also during

radiative

loss

face

sky

the

(which than

is

the night,

the infrared

greater for horizontal surfaces which

for vertical ones) and the heat supplied by

conductivity

from the interior (this must be considered for a non

homogeneous

monument)

dishomogeneities. end

of

the

humidity shaded

night

in

the

parts

micropores

The

and

lead

to

more

moderate

temperature

risk of condensation is higher towards the

and

early

atmosphere

in the morning, when the specific rises

and

the temperature of some

of the monument doesn't rise above the dew point o f surface,

due

to

the

thermal

inertia

of

the

195 monument.

This

groundwater and

is

and

statues

not

the

rainfall

damp,

only way to fill micropores: rising

are very effective in making buildings

thus

accelerating

spalling, exfoliation and

formation of deterioration crusts. Water

in

micropores

is

responsible

for

many

undesirable

effects : i)

dissolution

mechanical

of some crystalline bondings and weakening of the

resistence;

chemico-physical This

process

properties

results

transpiration (ref.24)

recrystallization

when evaporation occurs (see Fig.1).

in weakening the stone and in reducing its

capacity,

such

of the solute with new

which

may

lead to severe deterioration

as

surface

microfractures, exfoliation, spalling

of

soluble salts through the stone, mainly due to

and sugaring ; ii)

transport

rainfall,

capillary

efflorescences

and

rise

of

ground dampness, evaporation; then

subflorescences,

obstruction

of

capillary

outlets ; iii)

overpressure inside the porosities and capillary fringe when

liquid ratio

water of

18:22400

the

vapour

molar

However,

).

pressure) but

evaporates

is

and

the outlets are obstructed

volumes

of

liquid

water

and

( a s the

vapour

is

evaporation (and this potentially distructive

controlled

by

the

limited

diffusivity

of water

inside the pores and capillary system. However, a moderate

frequent

overpressure

may

result

in

the

flaking

off of

deteriorated surface layers; iv)

wetting-drying

capillary general, frequency involve

rise, a

Wetting

condensation;

is

mainly due to rainfall, is due t o evaporation. In

drying

o f deterioration phenomena can be related to the

lot of

cycles.

wetting-drying

dissolution,

cycles

migration

of

whatever

origin, which

and recrystallization of soluble

salts, as we will see below; v) freeze-thaw cycles in cold regions;

vi) endolithic o r epilithic biological activity. The

wind

affects

the

is

responsible

temperature

f o r many actions on a monument: it

pattern

especially

of

evaporating

196

surfaces;

it i s r e s p o n s i b l e f o r d i f f e r e n t t y p e s of w e t t i n g of t h e

monument,

furnishing

falling

drops

induces

the

cause

and

horizontal

component t o t h e v e l o c i t y of

causing preferential paths t o the run-off;

removal

abrasive

causes

a

o r d e p o s i t i o n o f a i r b o r n e p a r t i c l e s ; i t may

weathering

mechanical

it

stress;

in

the

zone c l o s e t o t h e ground; it

it

may

favour

the

loss

of p i e c e s

already very loose (ref.25). Evaporation masses solar

may

caused

have

energy

a

by

wind

different

heating

the

transporting

unsaturated

air

e f f e c t f r o m e v a p o r a t i o n c a u s e d by

monument. Wind p l a y s a v e r y i m p o r t a n t

i n i n c r e a s i n g t h e e v a p o r a t i o n r a t e , which i s a s s o c i a t e d w i t h

role the

transport

through

the

of

liquid

salts,

Wind c a u s e d e v a p o r a t i o n o c c u r s t y p i c a l l y on t h e s u r f a c e

salts a

where

containing

occurred.

evaporation

has

and t h e r e f o r e is e f f e c t i v e i n t h e t r a n s p o r t i n g of

walls

damp

recrystallization

water

dissolved of

and

stone

t o t h e s u r f a c e and forming e f f l o r e s c e n c e s , a s i n Venice, i n

v e r y humid e n v i r o n m n t , w h e r e t h e b u i l d i n g s a r e o n l y r a r e l y h i t

by

solar

developed

surface

the

evaporation

and

course

the

efflorescences

are

more

i n t h e more v e n t i l a t e d z o n e s , s u c h a s c o r n e r s e t c . When

the inner

Of

radiation. is

onger s u p p l i e d with water from c a p i l l a r i e s ,

no rate

drops

s i n c e e v a p o r a t i o n now o c c u r s i n t h e

a n d w i n d f a v o u r s t h e s l o w d i f f u s i o n o f water v a p o u r

pores,

t h e c o n t i n u a t i o n o f t h e p r o c e s s . When e v a p o r a t i o n o c c u r s d e e p

inside

the

stone,

crystallize

in

structure

are

s a l t s d i s s o l v e d i n t h e evaporating water

stone

i n t e r i o r . I n t h i s case t h e mechanical

weakened not

but

in

a

minor

manner

and

formed, t h u s r e d u c i n g t h e p r o b a b i l i t y of

If d u r i n g t h e n i g h t c o n d e n s a t i o n d o e s n o t o c c u r , t h e

exfoliation. efflorescences the

the

remains

efflorescences

washed

the

away

by

remain

on

rain.

the

surface

and

can be p e r i o d i c a l l y

In t h e c a s e of r e g u l a r c o n d e n s a t i o n d u r i n g

n i g h t ( a s i n Venice), t h e e x t e r n a l efflorescences can migrate

again

into

the

outer

l a y e r of t h e damp w a l l s , a c c e l e r a t i n g t h e

distructive process. Solar

water

on

radiation the

supplies

surface

e n e r g y t o t h e s t o n e and t h e l i q u i d

a n d i n s i d e , so t h a t e v a p o r a t i o n may o c c u r

197

also

in

raises

t h e i n t e r n a l m i c r o p o r e s when t h e t e m p e r a t u r e o f t h e w a l l i n t e r n a l r e l a t i v e h u m i d i t y o v e r c r i t i c a l l e v e l s which

the

locally

depend

outlets.

The

of

water

be

increased

the

increase of

complex

geometry of t h e p o r e s and t h e i r

f a c t o r l i m i t i n g t h i s p r o c e s s i s t h e low d i f f u s i v i t y by

humidity

added

is

of by

w i n d a c t i o n . The l o w d i f f u s i v i t y t e n d s t o r a i s e

relative

vapour

caused

the

vapour t h r o u g h t h e p o r e and c a p i l l a r y s y s t e m , which can

internal

water

on

the

and

s t o p s e v a p o r a t i o n when new

t o t h e i n t e r n a l a t m o s p h e r e . However, t h e

p r e s s u r e w i t h i n t h e c a p i l l a r y and porous system

t h e warming o f t h e i n t e r n a l a t m o s p h e r e , d i s p l a c e s p a r t

l i q u i d water w h i c h i s i n t h e i r n e c k s , o u t o f i t s o r i g i n a l

the

position,

so

stone

i t s l i q u i d phase (ref.23).

in

t h a t a s m a l l p o r t i o n may a l s o b e f o r c e d o u t s i d e t h e The e v a p o r a t i o n o c c u r r i n g i n

t h e i n t e r i o r s t o n e i s l e s s d a n g e r o u s , a s we h a v e a l r e a d y s e e n . Another gusty

character

formed

on

causes

rapid

that

tends

(and

with

the

i n s t a b i l i t y g e n e r a t e d by e d d i e s

monument t o a l e s s e r e x t e n t ) , w h i c h a l t e r n a t i v e l y

the

porosities so

e f f e c t of t h e w i n d i s a s s o c i a t e d w i t h i t s

noticeable

and u n d e r p r e s s u r e s between t h e a i r i n s i d e t h e

over

a n d c a p i l l a r i e s , a n d t h e a i r e x t e r n a l t o t h e monument, a

n e t a l t e r n a t i n g f o r c e i s applied t o t h e surface. This

t o d e t a c h s u p e r f i c i a l l a y e r s p o o r l y a t t a c h e d , that have

a reduced t r a n s p i r a t i o n c a p a b i l i t y . During the

r a i n f a l l t h e f l u c t u a t i o n s i n t h e e x t e r n a l p r e s s u r e and

dynamical

alternating

impedance

pressure

interior.

This

effect,

porosities

external

water

inside

the

surface

on

pores

and

capillaries

cause

g r a d i e n t s between t h e s t o n e s u r f a c e and i t s

internal

water

of

associated

results

in

the of

with

the

sink

effect

of

a n e t t r a n s p o r t and t r a p p i n g of

monument. monuments

Capillary

is

s u c t i o n of t h e

another

mechanism f o r

rainwater penetration.

term

Long due

to

a

dynamic

disturbance

obstacle,

can

dampness,

since

opposes

the

be

variations in

the

effective the

effects

induced

of p r e s s u r e , as occur l o c a l l y

mean in

w i n d f i e l d a s c a u s e d by a n

varying

pressure

the

rise

gradient

of

ground

increases

or

o f c a p i l l a r i t y a n d o s m o s i s . T h e s e l o n g term

198

pressure

g r a d i e n t s a c r o s s w a l l s make a n e g l i g i b l e c o n t r i b u t i o n i n

favouring

or

opposing p e n e t r a t i o n of r a i n w a t e r t h r o u g h s t o n e and

m o r t a r , b u t may b e i m p o r t a n t i n t h e c a s e o f c r a c k s . In

polluted

regions

wind i s a v e r y i m p o r t a n t f a c t o r i n

the

t r a n s p o r t i n g and d i f f u s i n g a i r b o r n e p o l l u t a n t s .

is

o n e o f t h e most i m p o r t a n t m e t e o r o l o g i c a l a g e n t s ,

when

it i s a s s o c i a t e d w i t h wind. P r o t r u n d i n g p a r t s of

Rainfall especially monuments

(like

an

exposed

due

to

falling

droplets.

is

rainfall

the

which

amount

of

deflection

cannot

the

of

t h e wind f i e l d t r a n s p o r t i n g

A p a r t f r o m t h e t r a n s p o r t of h e a t a n d momentum,

water

wet

lower p a r t s of b u i l d i n g s a r e l e s s

and

responsible

water, only

arm)

for

be

supplying

supplied

l a r g e amounts of l i q u i d

by m e a ns o f c o n d e n s a t i o n . The

s u p p l i e d by p r e c i p i t a t i o n c a u s e s r u n - o f f

surface,

depending

on

o r may

wind s p e e d a n d d i r e c t i o n ,

t o p o g r a p h y , e x p o s u r e a n d g e o m e t r y of t h e s u r f a c e . The w a t e r

local

supplied,

when

associated

with

a g g r e s s i v e c h e m i c a l a g e n t s , may

provoke c h e m i c a l r e a c t i o n s and t h e d i s s o l u t i o n of t h e s t o n e . The

dynamic

important.

loss

In

regime the

material

of

where

mechanical

water

in

of

zones

is and

less

the

water flowing over the stone is

characterized

by a l a m i n a r r e g i m e t h e

than i n zones with a t u r b u l e n t flow,

chemical

activity

(due

t o t h e m i x i n g of

c o n t a c t with t h e s t o n e ) a r e i n c r e a s e d . In h i g h l y porous

is

stone,

run-off

water,

s o t h a t t h e u p p e r p a r t of t h e d e s c e n d i n g s t r e a m , w h i c h h a s

abundant

water

dissolving laminar

the

regime

in

progressively

a

stone

turbulent

attenuated regime,

is

by very

t h e s u c t i o n of efficient in

and removing m a t e r i a l ; t h e lower p a r t i n a

d e p o s i t s t h e m a t e r i a l p r e v i o u s l y removed; f i n a l l y

t h e s t r e a m d i s a p p e a r s a f t e r t h e s u c t i o n of t h e r u n n i n g w a t e r . Rainfall the

intensity

is

also

important.

D r i z z l e may a c t i v a t e

d e p o s i t w i t h o u t w a s h i n g i t a w a y, a s i n t h e c a s e of h e a v y

dry

showers.

In

t h i s c a s e t h e pH of r a i n f a l l i s c l e a r l y o f s e c o n d a r y

importance,

compared

deposition.

Q u a n t i t a t i v e f i e l d m e a s u r e m e n t s show t h a t t h e l o s s i n

weight and

of

with

the

acidity

deriving

from

the dry

t h e limestone samples varies according t o t h e geometry

exposition

b o t h o f which d e t e r m i n e t h e t o t a l amount o f w a t e r

199

running over t h e surface. Frequency

and s e a s o n a l d i s t r i b u t i o n of r a i n f a l l a r e i m p o r t a n t

factors

in

the

stones,

which

maintenance

of

the

water content i n b r i c k s or

essential

in

the

c a s e o f some b i o l o g i c a l o r

is

chemico-physical weathering. Condensation-evaporation important to

the

due

pores

out

in

are

deposition

processes

and w e a t h e r i n g .

a i r , t h e o u t l e t s b e i n g o b s t r u c t e d by

their

further

condensation

is

prevented.

The

process

a v a r i a t i o n i n p r e s s u r e ( i n d u c e d by w i n d g u s t s o r

when

v a r i a t i o n i n t h e temperature of t h e s t o n e ) f o r c e s t h e water its

of

pore

original

(ref.23).

suction

due

p o s i t i o n t o be t r a p p e d i n t h e n e x t , l a r g e r

External

brings

However, air

the

retain

Thus,

continues a

micropores

water, l i k e a b o t t l e t u r n e d u p s i d e down a n d i m m e r s e d i n

condensed

by

the

first occurs i n t h e c a v i t i e s with smaller r a d i i , the

Condensation

water.

in

t o t h e i r f r e q u e n c y which c a n e v e n t u a l l y c o n t r i b u t e

increase

larger

cycles

about

condensation,

followed

by

capillary

g r e a t e r d e g r e e o f d a m p i n g of t h e s t o n e .

a

t o t h e condensation i n the smaller bottlenecks, the

p o c k e t s i n t h e i n t e r i o r o f t h e c a p i l l a r y s y s t e m may s t o p t h i s

process. Phoretic on

the

transport

stone

of

surface

a i r b o r n e p o l l u t a n t s and t h e i r c a p t u r e

are

regulated

by c o n d e n s a t i o n . However,

condensation

i s less important t h a n r a i n f a l l i n t h e d e t e r i o r a t i o n

process,

can

as

protected both.

from

The

be is

insufficient

amount

solution

heavy

0.5

per

mm

monuments along

with

the

gradually layer

is

and

processes

are

poor

much

is

active

porosity, collect. by

inner not

with

zones exposed t o

w a t e r f o r t h e f o r m a t i o n of a n a g g r e s s i v e

and

surface the

compared

dew f o r m i n g o n a n h o r i z o n t a l s u r f a c e i s a b o u t

mainly

absorbed

are

t h a t , i n g e n e r a l , condensation s u p p l i e s an of

night,

Condensation

zones exposed t o condensation b u t

if

rainwater,

reason (a

seen

the

on

the

where More

dry

on

vertical surfaces).

lower p a r t o f t h e s t o n e t h e l a r g e s t drops running

often

condensed

water

is

d e p o s i t , t h e e x t e r n a l weathered

porosities,

triggered.

less

so

t h a t severe deterioration

Under l o g g i a s , p o r t i c o s , t e r r a c e s

200

d i r e c t r a i n f a l l o r w i n d b o r n e d r o p r e t s d o n o t a r r i v e , we see

where that

the

is

water

is

stone not

well c o n s e r v e d , d e m o n s t r a t i n g t h a t condensed

sufficient

to

severe

trigger

physico-chemical

d e t e r i o r a t i o n , u n l i k e what i s popu1arl.y b e l i v e d . Condensed

water

may

be

sufficient

to

sustain

biological

a c t i v i t y , e s p e c i a l l y i n p e r i o d s of s c a r c e p r e c i p i t a t i o n . Wetting-drying conditions porous

cycles

would

be

materials

induce severe weathering. Steady-state

highly

desirable.

It

least

convenient

e n v i r o n m e n t a l l e v e l s of

the

i s obvious t h a t f o r

relative

humidity

are

relative

humidity

cause

adsorbed

by

humidity

l e v e l s . T h e r e f o r e extreme v a l u e s a r e p r e f e r r e d . H ow e ve r,

the

near-saturation and

the

those

in

greater

the

statue.

which

small variations i n the difference

in

t h e water

T h i s o c c u r s most o f t e n a t i n t e r m e d i a t e

c o n d i t i o n s may b e c o n d u c i v e t o b i o l o g i c a l a t t a c k ,

work

a r t r i s k s severe e f f l o r e s c e n c e s . D r y i n g c a u s e s

of

significant

mechanical

high

S t i l l w a t e r , may c o n s e r v e a n a r t i f a c t w i t h o u t r a i s i n g

rate.

serious

problems.

dissolved, in,

or

and

These

this

water

damage,

e s p e c i a l l y when t h i s o c c u r s a t a

arise

occurs

when p a r t o f t h e m a t e r i a l c a n b e

t y p i c a l l y when t h e body i s i m m e r s e d

o v e r i t . In g e n e r a l t h e b e s t c o n d i t i o n s a r e

flows

found i n s t e a d y , d r y environments. F r e e z e -thaw

cycles

condensation-evaporation the

scaling,

generally

is

a

is

not

deposit

temperatures

the

frost-point,

environmental the

saturation respect with

to

than

i n t h e Mediterranean region, but

for

and

materials

cracking. having

ice

small

damage

is

porosities.

c r y s t a l s b y d i r e c t s u b l i m a t i o n on o b j e c t s

b e l o w f r e e z i n g . The c r i t i c a l t e m p e r a t u r e , 1 . e . can

specific

moisture

be

calculated

as

content

occurs

a

function

of

the

h u m i d i t y b y m e a n s o f t h e Magnus e q u a t i o n . in

the

atmosphere

o c c u r s a t below z e r o t e m p e r a t u r e s ,

ice

The

r e s p o n s i b l e f o r t h i s k i n d o f damage. H o a r f r o s t

of

with

When

exfoliation

greater

Hoarfrost

cycles

frequent

s t r u c t u r e may b e s u b j e c t e d t o s t r e s s t h u s c a u s i n g

mechanical

surface

less

are

at

is

very

low,

but saturation with

a higher temperature than saturation

r e s p e c t t o s u p e r c o o l e d w a t e r , s o t h a t i n p r a c t i c e we see t h e

201

formation

of

a n d n o t o f s u p e r c o o l e d de w . H o a r f r o s t i n

is not a dramatic event, since d i r e c t sublimation occurs a t

pores very

slow

part

of

r a t e s and t h e growing ice c r y s t a l s occupy o n l y a s m a l l the

free

is

vapour

space i n t h e microcavities, a s t h e disposable

very

is

atmosphere

limited

and

negligible.

its

supply

Deterioration

from

the

external

i n t h e case o f

occurs

d e w , i . e . when t h e t e m p e r a t u r e of t h e s t o n e d e s c e n d s b e l o w

frozen the

hoarfrost

dew

water,

point and

of

then

the

so

micropores,

t h a t t h e y can f i l l with

s u c c e s s i v e l y b e l o w z e r o . The l a r g e r p o r e s w h i c h

r a r e l y become f i l l e d w i t h w a t e r , a r e l e s s e x p o s e d t o t h i s r i s k . Snow

deposited

sulphate

stone

(ref.26). melting

leads The

the

is

subject

been recognized a s i n h i b i t i n g

washes

out

precipitation

sulphuric of

calcium

acid

and

carbonate

of w e t t i n g t h e u n d e r l y i n g s t o n e d u r i n g t h e

effect

sequence be

to

has

it

precipitation;

eventually

may

on

more to

dangerous, a s t h i s water i n t h e stone freeze-thaw

cycles,

thus

inducing

crioclasticity. In

e n v i r o n m e n t s w i t h v e r y low o r low p o l l u t i o n l e v e l s ,

humid

biological

weathering

results

a

thin

s u r f a c e l a y e r ( a few

wide s e r i e s o f b i o l o g i c a l p r o c e s s e s ,

hundred

microns).

special

a t t e n t i o n s h o u l d b e g i v e n t o t h e a c t i v i t y of a l g a e , f u n g i

and

As

lichens.

calcium

a

oxalates means

analyses

of

r e s u l t of t h e i r a c t i o n , t h e p r e c i p i t a t i o n o f and

w h e w e l l i t e ) h a s been found i n

7)

of

investigation

a

(weddellite

some c a s e s ( r e f . 6 , By

Among

on

microclimatic

associated samples

of

together weathered

studies

and

microphysical

w i t h m i n e r a l o g i c and c h e m i c a l material,

p a r t of t h e above

processes

have

different

epochs

on

f u n d a m e n t a l p r o c e s s e s , which a r e o f t e n associat.ed w i t h ,

these

b e e n a n a l y z e d . O b s e r v a t i o n of many m onum e nts f r o m and s i t u a t e d i n v a r i o u s s i t e s , h a s thrown l i g h t

o r masked b y , o t h e r e f f e c t s . COMBINED A C T I O N OF POLLUTANTS AND RAINFALL In

this

quantitatively,

century but

also

air

pollution

qualitatively.

has High

changed

not

only

pollution levels

202

already past

existed

before

regulations

of

casual,

clearer these

are

oil)

due

to

the

combustion

characteristic

of

this

processes century.

A

between t h e i r i n c r e a s e d a p p e a r a n c e and s t o n e decay i s

correlation

not

28, 2 9 ) . However, h i g h c o n c e n t r a t i o n s

particles

of

t i m e , a s we c a n j u d g e f r o m

present

(ref.27,

carbonaceous

(especially

the

t h e i r r o l e i n t h e d e c a y o f monuments seem t o b e

and

than

in

the

c a s e of o t h e r c h e m i c a l components. In f a c t

c e n o s p h e r e s c o n t a i n many a g g r e s s i v e e l e m e n t s a n d c a t a l y s t s ,

and

are

characterized

31,

32,

33).

very

They become a c t i v e when w e t t e d by w a t e r , f o r m i n g a

aggressive

noticeably surface. gypsum

solution

enriched These

component

by a n e x t e n s i v e s p e c i f i c s u r f a c e ( r e f . 3 0 ,

of

by

where the

particles the

crystals

in

been

crusts,

which

deposited

a c i d i t y is

d r y d e p o s i t a l r e a d y e x i s t i n g on t h e

have

black

wet

the

found

are

which

these

soot

to

be an e s s e n t i a l

m a i n l y composed of

particles

are

embedded

3 5 ) . A n a l y s i s of b l a c k p a r t i c l e s and of t h e d e t e r i o r a t e d

(ref.34, layers

of

u r b a n monuments l e d t o t h e c o n c l u s i o n t h a t n o t a l l t h e

gypsum

in

the

crusts

transformation by

on

marble

monuments i s d e r i v e d f r o m t h e

t h e underlying rock, but it is a l s o enucleated

of

For t h i s r e a s o n t h e y remain

t h e s e black p a r t i c l e s ( s e e Fig.2).

more

readily

carbonatic

embedded

surfaces,

in

the

such

black

c r u s t , o r a t t a c h e d t o non

m e t a l s , wood o r g l a s s , w h e r e t h e y

as

f o r m b l a c k gypsum c r u s t s . The of

main

w e a t h e r i n g p r o c e s s e s a r e due t o t h e combined a c t i o n

rainwater

and

carbonaceous on

particles).

comparison

atmosphere, which

the

classified patterns: controls

to

in

pollutants (particularly

In a n u r b a n e n v i r o n m e n t t h e d r y d e p o s i t

of

into

formed

the

surface

three the on

white rate

the

scavenged

by

rain

from

the

r a i n o u t a n d w a s h o u t p h a s e s . The way i n

carbonatic

black, both

pollutants

both

monument

deterioration

crusts

atmospheric

s u r f a c e o f a monument may b e g r e a t e r t h a n a f a c t o r of t e n

the

in

various

kinds and

is

wetted

is

v e r y i m p o r t a n t . The

r o c k s i n u r b a n a r e a s c a n be r o u g h l y of v i s i b l y d i s t i n g u i s h a b l e f e a t u r e grey

areas.

The

way l i q u i d w a t e r

and t h e morphology of t h e d e t e r i o r a t i o n stone a s observed i n t h e f i e l d , indicates

203

that of

r a i n f a l l i s a critical f a c t o r i n determining t h e type

local

deterioratiQn

extensively

(see

Fig.3;

reported

with

r e f .36

4 1 . These r e s u l t s are

to

inaccuracies

some

in

ref.42

(pp

145-148) where t h e s o u r c e i s n o t c i t e d ) . Black with

crusts,

characterized

carbonaceous

are

formed

wetted the

in

by

zones

and

associated

is

sufficient

solution dissolved

and

crystallizes, particles

Under

in

run-off

these

marble

is prevented.

Their

which in

conditions

transformed

the

carbonaceous

the

meantime

crystals

are

an aggressive

l i m e s t o n e ) s u r f a c e which i s

(or

progressively

gypsum

particles,

where

w i t h t h e c a p t u r e of carbonaceous p a r t i c l e s

the

deposited

Further thus

on

o r by p e r c o l a t i o n a t t h e e d g e s o f

but

wetting.

forms

t h e s u r f a c e o f t h e monument i s o n l y

droplets

streams,

gypsum c r y s t a l s a n d c a l c i t e

embedded i n t h e c r u s t s ( s e e F i g . 4 ) ,

where

windborne

descending

origin

particles

by

into

gypsum

which

well a s t h e o t h e r

as

a r e embedded ( s e e F i g . 5 ) .

enucleated

by

the

carbonaceous

t h e s e a r e wetted. This s t r u c t u r e i s very porous,

when

f a v o u r i n g r e t e n t i o n of water and c a p t u r e of o t h e r p a r t i c l e s .

Whenever

wetted,

deterioration expense

of

of

further

is

a

the

active

continues, the

solution

f o r m s a n d t h e p r o c e s s of

and t h e c r u s t grows i n t h i c k n e s s a t t h e

underlying s t o n e and a l s o due t o t h e e n u c l e a t i o n

gypsum f r o m t h e p a r t i c l e s . F o r t h i s r e a s o n t h e damage

f u n c t i o n o f t h e time i n which t h e whole c r u s t i s c o m p l e t e l y

soaked

and

releases

the

a g g r e s s i v e s o l u t i o n , and n o t of t h e s o

c a l l e d time o f w e t n e s s . Similarly, and

spherical

transparent)

monuments important Brugges, monuments

of in

have

in

been

different the

countries

and

siliceous

particles

in

analogies

with

oil

the

in

in

,weathering fired

coal e.g.

Vienna

Edinborough.

gypsum p a t i n a of

the

where

energy

of

Cathedral

London

p a r t i c l e s (smooth, s p h e r i c a l

observed

production

Stephan's

S.

siliceous

combustion

is

t h e C a t h e d r a l of

and

many

English

The r o l e p l a y e d by t h e s e processes

carbonaceous

shows

certain

particles

(e.g.

n u c l e a t i o n o f gypsum c r y s t a l s , c o n t r i b u t i o n o f s u p h u r , e t c . ) For

conservation

purposes,

it

is

necessary

t o completely

204 remove

these

highly

intervention, 1973,

such

which

effectively

as

monuments,

the

but

the

the

the

remained

crusts.

special

prohibited reduced

cenospheres,

aggressive

law

Special

enacted

combustion

of

government

for Venice in

oil

in

Venice,

sulphur dioxide levels and the airborne

situation unchanged

of

the

black

crusts

on

the

that the deterioration process

so

continued relatively unalterd. Zones

experiencing

dissolution, underlying and

washout

rock.

heavy and

run-off partial

are

subject

to

partial

recystallization

of

the

This process results in a thinning of the stone

the formation of small authigenic crystals which are white in

appearance the

(white areas; see Fig.6).

The thinning depends on both

chemical activity and the dynamic state of the running water,

as discussed earlier. The black

grey areas do not have characteristics midway between the and

white

occurring

in

zones

A

condensation. formation into

of

black

ones. Their colour is due to the dry deposition remain

greater

dry

supply

of

(see water

Fig.7), except for would

trigger

the

an aggressive solution and transform the grey areas ones.

eventually

which

form

The

passage

white

a

of

bed.

a

rivulet

of

water

would

Dangerous chemical reactions are

prevented by the scarcity of the water supplied to this zone. DECAY PROCESSES OF MURALS AND FRESCOES BOTH INSIDE AND OUTSIDE After the also

having

external to

surface

consider

exceptionally However, the

as

context

examples, proposed

discussed

processes. Michelangelo

some

precious

main deterioration processes on

stone

monuments, it seems appropriate

of

the

mortars:

specific i.e.

problems

murals

affecting

and

frescoes.

they are often inside, a brief note would suffice in of

this

relative in

of

the

order The

paper. We will therefore only report a few

to

the

to

identify

clarifying frescoes

and

thermodynamic case the

theory

that

we have

the causes of the deterioration studies

made on the Giotto and

Leonard0

mural

have

extensively described in other papers (ref.43 to 48 and 19).

been

205

o f m u r a l s a n d f r e s c o e s r i s e s e s more d e l i c a t e a n d

Conservation complex

problems

more

porous,

more

distructive;

so

than

c o n s e r v a t i o n o f s t o n e . In f a c t , m o r t a r i s

that

t h e wetting-drying

c y c l e s a r e g r e a t e r and

i t c o n t a i n s a l a r g e r q u a n t i t y of s o l u b l e s a l t s

i s more e x p o s e d t o t h e r i s k o f e f f l o r e s c e n c e w h i c h c o v e r s t h e

and

image.

Mortar

moisture

has

content

underlying

thermal and

thermo-hygrometric favouring Any

modification

stone

as be

from

those

of t h e

may i n c r e a s e t h e d i u r n a l v a r i a t i o n o f t h e

mechanical

in

the

weakening

colour

appreciated.

of

and l o c a l detachment. mural

a

o r f r e s c o may be

For

painted surface the a r t i s t i c

a

contained i n a very t h i n s u p e r f i c i a l , d e l i c a t e l a y e r ,

content

is

whereas

carved

stone

may

it

different

s e v e r e d a m a g e , w h e r e a s t h e m o d e r a t e d i s c o l o r a t i o n of

may

before

are

which v a r y w i t h t h e

parameters i n r e l a t i o n t o t h e inner wall, thus

cracking,

regarded

these

This

wall.

characteristics

be

can

support

considered

l o s s of m a t e r i a l

greater

a

'damaged'.

Deposition

i t s e l f of

pollutants

and d u s t i s s t i l l 'damage' a l s o i n a b s e n c e of c h e m i c a l

reactions,

since

it

obscures

the

image

and e x p o s e s it t o t h e

r i s k s of necessary cleaning. Murals

f r e s c o e s are e x p o s e d t o o u t d o o r a s well as i n d o o r

and

environments. direct

rainfall

exposed

to

secondary indoor

In t h e l a t t e r c a s e t h e y a r e u s e f u l l y p r o t e c t e d from and

many

run-off other

( i n general); nevertheless they are

environmental

factors,

probably

of

i m p o r t a n c e , b u t e q u a l l y d a n g e r o u s i n t h e l o n g term. The environment,

controlled

which

characteristics

should in

a

be

accordance

limited with

the

zone

with

needs

of

i s , i n g e n e r a l , a m a l e f i c t r a p and an a g e i n g chamber

conservation

on t h e c o n t r a r y . In

the

painted

of

concentrations

room dust

the and

presence many

kinds

of v i s i t o r s c a u s e s high of

particles,

carbon

d i o x i d e and water vapour, b u t t h i s i s n o t t h e o n l y problem. Heating and In and

is

commonly

custodians, addition,

and

set

a c c o r d i n g t o t h e n e e d s of v i s i t o r s

n o t a c c o r d i n g t o t h e n e e d s o f t h e a r t work.

f o r p r a c t i c a l o r economic r e a s o n s i t i s s w i t c h e d on

off e v e r y d a y , c a u s i n g a s t e e p r i s e and a f a l l i n t e m p e r a t u r e

206

resulting

i n a c o n t r a r y c y c l e of r e l a t i v e h u m i d i t y .

we

section

have

variations: addition

etc.

other

temperature

is

This

d i s c u s s e d t h e d a n g e r o u s e f f e c t s c a u s e d by t h e s e

stress,

mechanical

efflorescence,

In a p r e v i o u s

transport

of

soluble

salts,

I n i n t e r n a l e n v i r o n m e n t s we m u s t c o n s i d e r i n

processes.

gradient

conducive

On

warming

develops to

the

close

the to

i n t h e room, a

air

the walls (see Fig.8).

thermophoretic

deposition

of s m a l l

particles

o n t h e s u r f a c e . The t h e r m a l g r a d i e n t i n d u c e s i n t h e a i r

close

t h e wall a d e n s i t y gradient, so t h a t t h e a i r i n contact

to

with

t h e c o l d e r s u r f a c e b e g i n s t o s i n k and a d e s c e n d i n g s t r e a m of

air

cooled

licks

the

walls.

Th us

inertial

d e p o s i t i o n of t h e

l a r g e s t p a r t i c l e s o c c u r s on t h e s u r f a c e o f t h e w a l l . v i s i t o r s a r e a source of moisture, diffusiophoresis occurs

As

due

to

the

is

There

a

direction room,

to

may

wall. the

net

between w a t e r vapour and d r y a i r .

d r a g of t h e s u s p e n d e d p a r t i c l e s i n t h e o p p o s i t e

i . e . towards t h e c e n t r e of t h e

the

greater

of t h e d r y a i r m o l e c u l e s . T h i s

mass

b e l o c a l l y c o u n t e r a c t e d by m o i s t u r e e s c a p i n g f r o m t h e condensation or evaporation occurs,

If

surface

a

hydrodynamic

Stefan

is

flow

i n t h e p r o x i m i t y of

generated ( t h e Stefan flow is a

f l o w which c o m p e n s a t e s t h e backward d i f f u s i o n of d r y

t h a t n o n e t m i g r a t i o n of a i r m o l e c u l e s t a k e s p l a c e ) . T h i s

so

air

diffusion

of t h e d i f f u s i n g vapour,

due

effect

mutual

i s v e r y e f f e c t i v e i n t r a n s p o r t i n g p a r t i c l e s , i r r e s p e c t i v e of

flow their

size,

vapour.

in

The

according

to

the

direction

opposed

pure

the

Maxwell

of

the

diffusion

diffusive

contribution,

is

equation,

of t h e w a t e r computed

o n l y 20 p e r c e n t o f t h e

Stefan contribution (ref.49). When windows

the

heating

system

i s s w i t c h e d o f f , o r when d o o r s a n d

are open f o r c l e a n i n g , t h e o p p o s i t e f l u x e s are e v e n t u a l l y

originated. density

Now

thermophoresis

gradient

deposition,

which

causes depends

an

gently upward

opposes flow,

but

deposition, the the

inertial

o n l y on t h e a b s o l u t e v a l u e o f t h e a i r

s p e e d , c o n t i n u e s i t s a c t i o n w i t h new s t r e n g t h . It

is

maintained

highly

as

r eco mmen d ed

that

the

indoor

t e m p e r a t u r e be

c o n s t a n t a s p o s s i b l e t o be i n e q u i l i b r i u m w i t h t h e

207

walls.

In order to attain this aim walls and air should be gently

warmed,

possibly with different systems, and without interruption

in

course

the

choosen or

on

that

year.

of

the

day.

The suitable temperature should be

basis of keeping the relative humidity constant,

only

minor

the

As

the and

gradual changes occur during the whole

relative

humidity

function

of

both

temperature

may

convenient to control the environmental temperature

more

rather

than

system

by

the

specific

means

specific

a

environmental be

and

is

humidity,

humidity, in general it

by controlling the heating

of a psychrometer and not just by a thermometer

alone. Lighting atmosphere

forcing

thermophoretic In

convective cells, thus favouring inertial and

deposition of particles on the murals or frescoes.

addition, when the lighting is switched-on, the energy emitted

(in

a

wide

abruptly, thermal is

also a serious problem: lamps supply heat to the

is

spectrum

which

is

rapidly

IR) hits the painted surface warmed,

causing a noticeable

for

mechanical

stress

and forced drying o f the

layer with an outward flux of moisture. The opposite occurs

when

the

colder

lamps are switched-off: the outer layer in contact with air

cools

readsorbing flaking with

then

to

gradient inside the wall. This overheating on the surface

responsible

outer

UV

from

moisture.

off

an

of

of

cycles

tempera

spectrum

emitted

established,

shrinks

These

the

energy

increase

and

the

result

still in

warm

wall,

microfractures,

and deposition of particles. Lamps

limited to the visible and with gentle

energy

are

over

till

preferable.

the

steady

Haloid

lamps

state give

rate

is

quite

satisfactorily results. The their

deterioration dynamics

spatial

and

moisture

spatial

and

their

be

temporal

between

the

can

as

the

gradients evolution;

the indoor atmosphere.

well

clearly evolution

as

the deposition processes and

recognized of

the

by

measuring: the

exchange of energy and

painted surface and the indoor atmosphere; of

the main thermohygrometric parameters

and the forced convection and stability of

2 08

a

As

close the

first

example,

increase

in the specific humidity

to the surface is an index of evaporation from the wall; if equivalent

have

temperature

(i.e.

the temperature that air would

if all the water vapour were condensed out isobarically,with

the latent heat

unchanged, has

an

it

been

if

being. used

to

heat

the

air)

is

means that the energy required for the latent heat

supplied

surface; wall,

released

the

by the air and that evaporation occurs on the equivalent

temperature

increases close to the

it means that the evaporation occurs inside the wall, which

supplies the energy required. If

the

relative

mural is hit by radiant energy, its surface warms and humidity

conditions is

if

not

the

in

its

proximity.

Under

these

specific humidity remains unchanged,the wall

subject

increases, air

decreases to

evaporation;

if

the

specific

humidity

the mural suffers from evaporation. The ascent of warm

licking

the

deposition.

surface

Evaporation

causes is

in

inertial

and

opposition

to

thermophoretic these

effects,

reducing the total deposition. In as the

another

case,

if the specific humidity increases as well

the relative humidity, it means that evaporation occurs inside wall

escapes

due

to a local rise in temperature and that the vapour

through

the

capillaries

(in

this

case instead of the

relative humidity we could use the equivalent temperature). Again, surface,

if the specific humidity decreases in proximity to the it

temperature relative

means is

that

condensation

homogeneous

occurs

and,

if the wall

and in equilibrium with the air, the

humidity indicates the size of the pores which are being

filled

with

water.

In

this

case

the

Stefan

flow

favours

deposition of particles on the wall. another

As

equals

the

wetness that cause,

example,

environmental

if wet

the

temperature

bulb

of a damp surface

temperature,

the

cause of

cannot

be

condensation since this temperature indicates

wall

is

evaporating,

the

has a different origin. If condensation occurs, the

which

temperature

and we must search for the true

of

the

wet surface should be equal to or lower than

209

the

environmental

dew p o i n t , a n d i n t h i s c a s e t h e p r o c e s s c a n b e

s t o p p e d by h e a t i n g t h e w a l l .

It

is

stop

not

difference is

point the

on

clean,

flat

warmed

surface,

air.

occurs

In

fact

o n l y when t h e

negative,

a n d d o e s n o t d e p e n d on t h e r e l a t i v e h u m i d i t y

in

of

proximity.

Condensation

on

micropores

or

in

soluble s a l t s occurs also with positive differences. warm

thermophoretic when

a

insufflating

t h e s u r f a c e t e m p e r a t u r e a n d e n v i r o n m e n t a l dew

of

flow

by

but a l s o dangerous, t o attempt t o

between

air

presence A

useless,

condensation

condensation

of

only

air

brings

de,positions

about

and

the

the

u n d e s i r e d i n e r t i a l and

formation

of e f f l o r e s c e n c e

t h e h e a t s u p p l i e d by t h e h o t f l o w e v e n t u a l l y r a i s e s t h e w a l l

t e m p e r a t u r e o v e r t h e dew p o i n t . These

well

e x a m p l e s show how a p r o c e s s c a n b e i n f l u e n c e d

few

as

a s t h e c a u s e . T h e r e f o r e , it i s , i n p r a c t i c e , p o s s i b l e t o a c t

directly the

on

t h e c a u s e , n o t o n l y on t h e e f f e c t s , i n o r d e r t o s t o p

deterioration

p r o c e s s . S u c h i n t e r v e n t i o n would be c o m p l e t e l y

u s e l e s s when t h e c a u s e s a r e s t i l l a c t i v e . CONCLUSIONS In

general,

complex

and

variables,

find,

p r o c e s s a p p e a r s t o be r a t h e r

b o t h c h e m i c a l compounds a n d m e t e o r o l o g i c a l

sometimes

involving

valid as

deterioration

involves and

relationships damage,

the

a

biological

pollution

attack. bulk

levels,

General

d e p o s i t i o n and

f o r a l l microclimatic conditions are impossible t o

meteorological

boundary

conditions,

different

processes

Different

Commissions

factors

should

n o t be o n l y c o n s i d e r e d

b u t i n d e p e n d e n t v a r i a b l e s which c a n t r i g g e r and must b e s t u d i e d from t h i s p o i n t of v i e w . and

Research

Groups

have

came

to this

important conclusion independently (ref.50 t o 52). An

analysis

meteorological

of

the

factors,

t h a t s h o u l d b e s t u d i e d on exchange only

the

m a i n d e t e r i o r a t i o n p r o c e s s e s i n d u c e d by has

t u r n e d up

important consequences

t h e b a s i s of t h e thermodynamics and t h e

o f h e a t a n d m o i s t u r e b e t w e e n s u r f a c e a n d a t m o s p h e r e . Not microclimate,

but

also

the

microphysical processes,

210

that be

are

the

in general rather complicated and p'oorly known, should

object

furnish

the

of

interdisciplinary

necessary

key

in

research, since they often

understanding

the deterioration

mechanisms. It and

appears

actua ly

limestone

monument: (white

the different weathering observed on marble

that

from

areas),

depends

on

the

way

the rain wets the

one

extreme

to

he other where the surface is wetted and the

a

complete

washout of the surface

dry deposit is not removed but activated (black areas). particular

A

the

water

this a

is

case

clear

is the slightly wetted surface, i.e. when

adsorbed and can't form an aggressive solution. In

the stone appears well conserved (grey areas).

This is

demonstration that dry deposition in itself may be not a

sufficient unless

case

f o r the deterioration of exposed stonework,

condition

water

is

deterioration

supplied

processes.

in sufficient quantity to trigger the In

this

respect, condensation plays a

minor role compared to rainfall. The the

deterioration of monuments depends o n the aggressivity of

solution which forms on them when they are wetted. Therefore,

especially

in

urban

areas

where

dry deposition dominates, the

concentration of hydrogen ions in rainfall may

of

be

contribution solution

secondary of

which

the is

dry

importance

in

deposition.

The

comparison

with

the

concentration of the

formed on the monument surface depends on the

intensity of rainfall. In is

not

the

case of relatively unpolluted towns, where sulphation

the

main

deterioration

cause of the deterioration process, biological

mechanisms

are

often

very

important, due to the

activity of epilithic and endolithic microflora and microfauna. Finally, murals

or

the case of particularly precious mortars, i.e. with frescoes, has

thermodynamic

method

been discussed in order to clarify the

proposed

for

the analysis of experimental

campaigns. To take necessary action one should not act only the effects but also on the causes.

on

211 ACKNOWLEGMENTS of

In

this

Dr.

A.

Sabbioni to

p a p e r t h e m a i n r e s u l t s o f t h e w o r k i n g g r o u p composed Bernardi,

0 . V i t t o r i f o r many u s e f u l t h e o r e t i c a l d i s c u s s i o n s . The

was c a r r i e d o u t u n d e r a c o n t r a c t of t h e Commission

present

study

of

European

the

National

the

'Piano

'Progetto

Del Monte, Dr. C.

a n d D r . S . V i n c e n z i a r e r e p o r t e d . The A u t h o r i s g r a t e f u l

Prof. the

D r . D. Camuff o, P r o f . M.

C o m m u n i t i e s (ENV 757/I/SB).

Research Strategic0

of I t a l y was p a r t l y s u p p o r t e d by

Council Clima

The c o n t r i b u t i o n of

e

Finalizzato Energetica 2'

Ambiente'

.

and

partly

by

the

REFERENCES

1

2 3 4 5 6 7 8

9 10 11

12

13 14 15 16 17

R.A. Livingston and N.S. Baer, Proc. 6th World Congress on A i r Q a l i t y , Int ernat i onal Union of A i r Pollution Association, P a r i s , 16-20 May 1983, Prepri nt , pp. 8. P. Brimblecombe, Tellus, 30 (1978) 151-157. House of Comons, Acid Rain. 4th Report from t h e Environment Committee. HMSO, London, 1984, p. 76. United States Environmental Protection Agency, Acid Rain, Report EPA-600/9-79-036, Washington, 1980, p. 36. D. Camuffo, M. Del Monte and A. Ongaro, The Science of t h e Total Environment, 40 (1984) 125-140. M. Cel Monte and C. Sabbioni, Environ. Sci. Technol., 17 (1983) 518-522. M. Del Monte and C. Sabbioni, The Science of t h e Total Wvironment, (1986) i n press. L. Marchesini, G. Biscontin and S. Fra s c a ti, Relazione t r a p o r o s i t a ' ed invecchiamento d e i marmi saccaroidi.Report of C.N.R. Centro d i Studio s u l l e Cause d i Lkperimento e Metodi d i Conservazione d e l l e Opere d' A rte , 1972, No.19, Rome. A. Wexler, h m i d i t y and Moisture, Reinhold Publishing Corporation, New York, 1965, V01.111, p. 562, Vol. IV, p.333. R.S. Scorer, A i r Pollution, Pergamon Press, Oxford, 1968, p. 151. T. Stambolov and J.R.J. van Asperen de Boer, The L kte riora tion and Conservation of Porous Building M a te ria ls i n Monuments, 2nd ed., Int ernat i onal Centre f o r Conservation, Rome, 1976, p . 86. M. Eenarie, i n Commission of t h e European C o m n i t i e s (Eds), Proc. The E f f e c t s of A i r Pollution on H i s t o r i c Buildings and Monuments, Padua, 30 September - 2 October, 1985. XII/ENV/3/86, Bruxelles, 1986, pp. I I -2- I I. 33. D. Camuffo, A. Bernardi and P. L c c i , Boundary Layer Meteorology, 22 (1982) 503-510. D. Camuffo and A. Bernardi, Boundary Layer Meteorology, 23 (1982) 359-368. D. Camuffo, Boundary Layer Meteorology, 28 (1984) 199-205. D. Camuffo, S . Vincenzi and L. Pilan, Water, A i r and S oil P ollution, 23 ( 1984) 451-454. D. Camuffo and S. Vincenzi, The Science of t h e Total Environment, 44 (1985) 159-163.

212

18 I. Lavagnini, D. Camuffo and A. Bernardi, The Science of t h e Total Environment. 50 (1986) i n p r e s s . 19 D. Camuffo and S. Vincenzi, The Science of t h e Total kvironment, (1986) i n press. 20 D. Camuffo, Atmospheric Environment, 15 (1981) 1767. 21 D. Camuffo and S. Vincenzi, The Science of t h e Total Environment, 44 (1985) 159-163. 2 2 S.J. Gregg and K.S.W. Sing, Academic Press, London, 1967, 371 pp. 23 D. Camuffo, Water, Air and S o i l P o l l u t i o n , 21 (1984) 151-159. 24 A. Ekrnardi, D. Camuffo, M. Del b n t e and C. Sabbioni, The Science of t h e Total h v i r o n m e n t , 46 ( 1985) 243-260. 2 5 J. Delgado Rodrigues and J.A. G i l Saraiva, Proc. 5th International Congress on Deterioration and Conservation of Stone, Lausanne, September 25-27, Press Polytechniques Romandes, Lausanne, 1985, pp.167-175. 26 M. Del Monte, C. Sabbioni and G. Zappia, The Science of t h e Total Environment, (1986) i n p r e s s . 27 A.C. S t e r n , Air P o l l u t i o n , Academic Press, New York, I , 3th ed., 1976, p. 715. 28 P. Brimblecombe, London Air P o l l u t i o n , 1500-1900. Atmospheric Environment, ll(1977) 1157-1162. 29 N.S. Baer and P.N. Banks, The I n t e r n a t i o n a l Journal of hseum Management and Curatorship, 4 (1985) 9-20. 30 P. Bacci, M. Del Monte, A. Longhetto, A. Piano, F. Prodi, P. Radaelli, C. Sabbioni and A. Ventura, J. Aerosol S c i . , 14 (1983) 557-572. 31 M. Cel Monte and C. Sabbioni, Arch. Met- Goeph. Biocl., B 35 (1984) 93-104. 32 M. Del Monte, G.M. Braga Marcazzan, C. Sabbioni and A. Ventura, J. Aerosol Sci., 15 (1984) 323-327. 33 M. Del Monte, C. Sabbioni and 0. Vittori, Atmospheric Environment, 15 (1981) 645-652. 34 M. Del Monte, C. Sabbioni, A. Ventura and G. Zappia, The Science of t h e Total k v i r o n m e n t , 36 ( 1984) 247-254. 35 M. Del h n t e , C. Sabbioni and 0. V i t t o r i , The Science of t h e Total Environment, 36 (1984) 369-376. 36 D. Camffo, M. Del Monte, C. Sabbioni, and 0. V i t t o r i , Atmospheric Environment, 16 (1982) 2253-2259. 37 D. Camuffo, M. Del Monte, and C. Sabbioni, Water, Air and S o i l Pollution, 19 (1983) 351-359. 38 D. Camuffo, Atmospheric Environment, 18 (1984) 2273-2275. 39 M. Del b n t e and 0. Vittori, Ekdeavour, 9 (1985) 117-122. 40 D. Camuffo, M. tkl Monte and C. Sabbioni, Ministero d e i Beni C u l t u r a l i ed Ambientali, E b l l e t t i n o d ' Arte, s p e c i a l i s s u e ( 1986) i n p r e s s . 41 A. Ekrnardi, D. Camuffo, M. Pel h n t e , C. Sabbioni, S. Vincenzi and G. b p p i a , comnission of the European ( h m i t i e s (Eds), Roc. The E f f e c t s of Air P o l l u t i o n on H i s t o r i c Euildings and Monuments. Padua, 30 September - 2 October 1985. XII/ENv/3/86, 1986, Bruxelles. 42 G.G. Amoroso and V. Fassina, Stone &cay and Conservation, Elsevier, Amsterdam, 1983, p 453. 43 D. Camuffo and P. Schenal, E o l l e t t i n o d'Arte d e l Ministero per i Ekni b l t u r a l i e Ambientali, s p e c i a l i s s u e (1982) 119-220. 44 D. Camuffo, Atmospheric Environment, 17 (1983) 1803-1808. 45 D. Camuffo, I n N.S. h e r and R.A. Livingston (Hs.), Proc. Workshop AH Environmental Monitoring for Architectural Conservation, Rome, June 11-14,

213

1984, New York University, New York, 1986, i n p r e s s . 46 D. Camuffo and A. Bernardi. F a t t o r i microclimatici e conservazione d e i beni a r t i s t i c i . Edizioni d e l Laboratorio. ENAIP, Botticino (Brescia), 1985, p.63. 47 D. Camuffo and S. Valcher, Wvironmental Monitoring and Assesment, 6 (1984) 165-170. 48 D. Camuffo and A. Bernardi, B o l l e t t i n o Monumenti Musei e Gallerie Pontif i c i e , s p e c i a l i s s u e ( 1986) i n p r e s s . 49 0. Vittori, I1 Nuovo Cimento 7C, 2 (1984) 254-269. 50 M. Benarie, i n N.S. h e r and R.A. Livingston (Eds.), Proc. Workshop ARW Ehvironmental Monitoring f o r Architectural Conservation, Rome, June 11-14, 1984, New York University, New York, 1986, i n p r e s s . 51 Commission of t h e European Cornunities (Eds), R o c . The E f f e c t s of Air P o l l u t i o n on H i s t o r i c Wlildings and Monuments. Padua, 30 September - 2 October 1985. XII/ENV/3/86, 1986, Bruxelles. 5 2 Economic Commission f o r Europe, Air-Borne Sulphur Pollution. E f f e c t s and Control. Air P o l l u t i o n Studies 1 . United Nations, New York, 1984, 265 pp.

214

Fig. 1. ( a ) Gypsum c r y s t a l l i z e d w i t h i n t h e i n t e r n a l c a v i t i e s of l i m e s t o n e ( N i c o l s X , 4 6 5 ~ ) . (Reduced by 1 0 % ) ( b ) O o l i t h i c l i m e s t o n e s h o w i n g c a l c i t e c r y s t a l s r e p r e c i p i t a t e d on t h e o o l i t e ( N i c o l s X , 4 6 5 x 1 . (Reduced by 10%)

215

Fig. 2. Carbonaceous p a r t i c l e s enucleating gypsum crystals conditions (wetting i n absence e l e c t r o n micrograph, 2 5 0 0 ~ ) .

e m i t t e d by c o m b u s t i o n p r o c e s s e s under laboratory controlled of sulphur dioxide) (scanning

2i6

Fig. 3. Examples o f w h i t e and b l a c k a r e a s due r e s p e c t i v e l y t o t h e run-off on t h e s u r f a c e ( w h i t e a r e a s ) and d e p o s i t of c a r b o n a c e o u s p a r t i c l e s a n d s u l p h a t i o n of t h e u n d e r l y i n g s u r f a c e i n t h e z o n e s w e t t e d by a i r b o r n e d r o p l e t s a n d p e r c o l a t i o n , b u t p r e v e n t e d from run-off ( b l a c k a r e a s ) . T h e i r s h a p e i s d e t e r m i n e d by t h e g e o m e t r y o f t h e monument. ( a ) C a p i t a l of t h e D u c a l P a l a c e i n V e n i c e . ( b ) S t a t u e o n t h e C o n s t a n t i n o ' s A r c h i n Rome.

217

(a)

Fig. 4. (a) Black c a r b o n a c e o u s p a r t i c l e s embedded in t h e g y p s u m c r u s t s are c l e a r l y e v i d e n t . Between t h e unaltered limestone and t h e sulphated c r u s t , a layer of reprecipitated c a l c i t e (which a p p e a r s white in t h e m i c r o g r a p h ) can be observed (Nicols / / , 1 8 5 x ) . (Reduced by 10%) ( b ) C a r b o n a c e o u s p a r t i c l e s are uniformly distributed inside the crust (Nicols / / , 4 6 5 x 1 - (Reduced by 10%)

2 18

Fig. 5. Examples of a black area observed in transversal thin section. a) Acicular gypsum c r y s t a l s with radial orientation grow on the limestone (Nicols X , 1 8 5 ~ ) . ( b ) In some cases, the sulphated crust c d n s i s t s of authigenic calcite and gypsum (Nicols X , 4 6 5 x 1 . (Reduced by 10%)

219

Fig. 6. Examples o f a w h i t e a r e a o b s e r v e d i n t r a n s v e r s a l t h i n section. ( a ) D i s s o l u t i o n due t o run-off p r o d u c e s embayed s u r f a c e . The washout o f u n s a t u r a t e d r a i n w a t e r p r e v e n t s from r e p r e c i p i t a t i o n (Nicols X, 465x1. ( b ) The r e p r e c i p i t a t i o n o f s p a t i c c a l c i t e c a n be o b s e r v e d a t t h e e d g e o f t h e w h i t e a r e a w h e r e t h e r u n - o f f i s l e s s i n t e n s e . G e n e r a l l y t h e s e w h i t e a r e a s show n o gypsum ( N i c o l s x. 4 6 5 x 1 . ~ R P ~ I I C C ChI v 10%)

220

Fig. 7 . T r a n s v e r s a l t h i n s e c t i o n of a g r e y a r e a , s how ing a of p a r t i c l e s o v e r t h e s t o n e s u r f a c e . The compact deposit u n d e r l y i n g m a r b l e a p p e a r s n o t t o b e a f f e c t e d by w e t h e r i n g ( N i c o l s

/ / , 180x1.

221

Fig. 8 . T h e r m a l maps of t h e S i s t i n e C h a p e l , o n : 7 May ( a ) , a nd 9 ( b ) May 1 9 8 3 . ( a ) S i t u a t i o n i n t h e e a r l y m o r n i n g when c o l d a i r e n t e r s t h r o u g h t h e o p e n d o o r s ( i n d i c a t e d by a r r o w s ) . The w a l l s a r e warmer t h a n t h e atmosphere. T e m p e r a t u r e r a n g e : 16. 8 t o 1 8 . 9 C ( b ) S i t u a t i o n a t mi d-morni ng when t h e i n t e r n a l a t m o s p h e r e h a s b e e n warmed w e l l a b o v e t h e t e m p e r a t u r e of t h e w a l l s . T e m p e r a t u r e r a n g e : 19. 7 t o 22.1 c.

T. Schneider (Editor)/Acidificationand its Policy Implications @ Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

223

EFFECTS OF ACIDIFICATION ON ARTIFACTS IN ARCHIVES AND MUSEUMS

N.S.

BAER

Conservation Center8 New York University8 14 East 78th Street New Yorkt New York (U.S.A.)

ABSTRACT The pollutant sources leading to indoor acid deposition; types of damage observed; and SO2 and NO, levels measured are reviewed for archives1 libraries and museums. Recently proposed air quality design criteria for heating, ventilation and air conditioning (HVAC) systems for cultural institutions are presented. INTRODUCTION The effects of acid deposition on cultural property in archives, libraries and museums have previously been reviewed in the context of indoor air pollution (ref. 1 1 2 ) ~indoor particulate deposition (ref. 3 ) acid ~ deposition effects on cultural property (ref. 4 1 8 and air pollution damage to materials (ref. 586). In the following discussion the sources of indoor acid deposition8 typical manifestations of damage8 pollutant levels observed8 and suggested design criteria for air handling systems are considered. HISTORICAL BACKGROUND Soon after the introduction of coal as a fuel for kilns in England, complaints were made regarding smoke. In the records of Dunstable it was noted that in 1257 Eleanor8 Queen of Henry I111 left the town of Nottingham because of smoke from sea-coal. In the reigns of King Edward I and Queen Elizabeth proclamations forbidding the use of coal during the sitting of Parliament were issued (ref. 7).

224

Brimblecombe has demonstrated that such concerns received official attention as early as 1284 when a Royal Commission was appointed to investigate air pollution from coal used as a fuel for kilns in London and Southwark (ref. 8-11). In the seventeenth century many references were made to pollutant soiling of household materials. Evelyn in his . . m m o f ? published in 1661r wrote: It is this horrid Smoake which obscures our Churches# and makes our Palaces look old# which fouls our Clothes? and corrupts the Waters? so as the very Rain? and refreshing Dews which fall in the several Seasons, precipitate this impure vapourt which? with its black and tenacious quality, spots and contaminates whatever is exposed to it. It is this which scatters and strews about those black and smutty upon all things where it comes? insinuating itself into our very secret Cabinetst and most precious Repositories: Finally? it is this which diffuses and spreads a Yellownesse upon (ref. 12). our choycest Pictures and Hangings

...

In 1850 a commission composed of Charles Eastlake, Michael Faraday and William Russell reported to the House of Commons: In considering the position of the National Gallery? our attention was drawn to the vicinity of several large chimneys, particularly that of the Baths and Washhouses, and that connected with the steam-engine by which the fountains in Trafalgar-square are worked? from which smoke are emitted. In the neighbourhoodr also? the numerous chimnies of the various club-houses are constantly throwing out a greater body of smoke than those of the ordinary private residences.. (ref. 13).

.

In addition to the dust and smoke that entered the building as windows were opened to provide ventilation? specific pollutants were associated with the visitors:

...

the greater also will be the quantity of impurity produced within the building from the respiration and perspiration of great numbers of persons; this impure mass of animal and ammoniacal vapourr of which it is difficult and perhaps unnecessary to distinguish and define the component parts, is peculiarly liable to (ref. be condensed on the surface of the pictures 13).

...

225

The results of the assault of various forms of pollutant deposition on the pictures were immediately obvious: Many of them present the appearance of being covered with a thick film, alike foreign in feature and in color to the original character of the picture, detracting from its highest qualities, and depriving it for the time of clearness and brilliancy (ref. 13).

More recently, Hudson studied the acidity of paper in books from two libraries; Chatsworthr in open Country, some 25 miles east of Manchester; and the Portico Library located in the polluted urban atmosphere of Manchester (ref. 14). Surface pH measurements were made at the topr center and side of pages for 25 identical copies of books. Hudson concluded that atmospheric pollution was a cause of the lower pH values observed? particularly at the edges of the books in the Portico Library. A statistical evaluation of these data concluded that to the degree that contact pH f o r the two groups of books can be attributed to library location and position on the page? the low pH at the edges as compared to the less exposed center may be attributed with great confidence to the differing conditions of storage at the two libraries (ref. 15). However, this and other retrospective studies have encountered difficultly in separating the effects of local ,502 concentrations from variations in average annual temperature? frequency of use? and differing maintenance practices. POLLUTANTS AND THEIR EFFECTS Indoor pollutants in archives? historic houses? libraries, and museums derive from outgassing of structural or decorative materials, heating plants? activities of visitors and staff, and the intrusion of outdoor pollutants. In some cases the artifacts themselves emit significant and possibly dangerous amounts of pollutant gases. The types of damage observed, principle air pollutants causing damage, other significant environmental factors, and methods of measuring damage are given in Table 1.

226 TABLE 1. I n d o o r A i r P o l l u t i o n Damage t o M a t e r i e l s .

Type O Impact

f

Principal A i r Pollutant8

Other Envi ronmenta 1 Factors

Signal quality, p h y s i c a l end chemical 8n8LySiS

Magnetic Storage lladie

LOSS O f

Sign81, tape f a i Lure

Particles, moisture

Meta 1s

Corrosion, t a r n i shing

Su L f u r Oxi d8S, and o t h e r a c i d l c gllses, hydrogen su L f id8

Moisture. a i r , 811 t t , p e r t i c u l a t a m8tf8r.

OZOn8

Weight 108s e f t a r removal o f COP r o s i o n products, chenge i n 8 U r f 8 C 8 Ch8r8CteriStiC8

Pai n t i n g s and Organic Coatings

Discoloretlon, s o i Ling

% l f U r OXid86, hydrogen s u l f i d e , 8 Lk8 LinS 8 8 r O S O L

Moisture, s u n l i g h t , ozone, p e r t i c u l a t e matter, m i c r o o r g e n i sms

Surface r e f l e c t i v i t y Loss, chemiceL analysis

Paper

Emb r i tt lement,

S u l f u r oxides

Moisture. p h y s i c a l wear, a c i d i c m e t e r i e l s introduced i n manufacture

Decreased f o l d i n g endurance, pH Change. mo l e c u l a r weight measurement, t e n s i l e st rength.

discoLoretion, acidification

Photogr e p h i C Materiels

Microb Lemishes, "su l f i d i n g "

Su Lfu r o x i das. hydrogen s u l f i d e

P a r t i c u l a t e matter. mo i6 t u r e

V i s u a l end microscop i c examination

T e x t i Les

Reduced tene i Le s t r e n g t h , soi l i n g

S u l f u r end nit r o g e n Oxide8

P a r t i c u l a t e matter, moisture, l i g h t , p h y s i c a l weer, weshing

Reduced t e n e i l e S t renpth, C h 8 m l C 8 L e n e l y e i s [e.g., molec u l a r weight], aurface r e f l e c t i v i t y

T e x t i l e Dyes

Fading. c o l o r change

Drone. n i t r o p e n oxides

Light, high temperature

RefLeCt8nC8 end C o l o r value meeeuremente

SULfUr Oxide8

P h y s i c a l Weer, residue1 ecids introduced i n menufacture

Loss i n t e n s i l e strength. c h s l l l c e l enelyeis, shrinks98

Leather

Of the pollutants affecting cultural property, SO2 has received, by far, the greatest attention. As noted above, there is a long history of association of damage with SO2 deposition. The high ambient SO2 levels accompanying industrialization were seen to have increased the rate at which damage occurred? though other factors in some cases, e.g. the use of groundwood pulp and changes in papermaking practice were the root causes for the decline in permanence. In recent years, increasing concern over NOx has developed as ambient levels increased. With the possible exception of photographic microblemishes and damage to some textile fibers, few documented examples of damage to cultural property exposed to high ambient NOx levels have been reported. More frequently, damage has been observed for objects exposed to organic acids given off by such construction materials as plywood, fiberboard and poly(viny1 acetate) adhesives. Particularly suseptible are lead objects where growth of lead acetate and lead formate transformation products seriously disfigure objects (ref. 1). In general, atmospheric acidic gases are introduced into the museum or library environment as makeup air is brought into the HVAC system. Typically? 10% of the air in a cycle is taken from the exterior while 90% is recirculated. With an average of 6 air changes per hour, the museum environment, in the absence of pollutant removal, will soon equilibrate with exterior pollutant levels. That lower SO2 and ozone levels are observed in museum and library interiors is a result of the high rate of deposition of these gases on paper, leather, textiles and other surfaces found in cultural institutions. In Table 2 the measured indoor SO2 and NOx levels reported for libraries, archives, and museums are given. It is obvious that several technologies? e.g. water washing? activated carbonr potassium permanganate coated alumina (Purafil)I are capable of effectively removing S 0 2 . Unfortunately, the wash

228 TABLE 2. Measured I n d o o r O u t d o o r P o l l u t i o n Levels f o r Archives,

Institution

POL LUtent

Dates Measured

L i b r a r i e s and Uuseums.

Exterior Concentration

Interior Concent r a t i o n

F i Ltration system

NARS [ A r c h i v e s Bui Lding)

Nov. 1977

32-40 ppb <3 PPb [ l o x reduction]

P a r t i c u Late

NARS [ A r c h i v e s Bui l d i n g ]

oec. 1982Jan. 1983

7-34 ppba d a i Ly sverage

Particu l e t s

National Gallery [East B u i l d i n g ]

Fab. 1983

7-34 ppba dEi l y average

L i b r a r y o f Congress [Madison Bui Lding]

Jan. 1983

7-34 ppbe d a i l y everags

R i j keauseua [Amsterdam]

Fab .-Mar. 1976

957ppb

1-6 ppb

Tete Gallery [ London]

1 9 B D I983

12-80 ppb

0-4 ppb

A c t i vetad Carbon

Victoria 6 Albert [London]

Jsn.-feb. 1983

22-60 ppb

3-42 ppb

None

NARS

Sept. 1977

41 ppb average

20-90 ppbb

Particulate

NARS [ A r c h i v e s Bui L d i n g l

Dec. 1982Jan. 1983

1 0 5 2 7 ppba

10-252 ppb

P a r t i c u Late

Netlonet Gallery [East B u i l d i n g ]

Feb. 1983

40-62 ppba

7-50 ppb

Water Wash

L i b r a r y o f Congress [Madteon B u i l d i n g ]

Jan. '1983Fab. 1983

46-318 ppb'

4 1 5 4 ppb

Purafil

Huntington L i br ar y [Sen Mnrtno. CAI

0ct.Nov. I S 6 4

37r~pb

Particulate

[ A r c h i v e s Bui L d i n g l

2-25 ppb

-<1 ppb -W.5

ppb

..

38Dob

a Measured a t 2 4 t h and L S t r e e t s . N.W. Followed e x t e r i o r .

b y t h e D i s t r i c t of Columbia.

wetar Wash PurafiL

I

Reference

229

and Purafil systems are much less effective for NO, removal than for SO2 removal. These results are surprising since Purafil is clearly effective in the laboratory. AIR QUALITY STANDARDS FOR ARCHIVES, LIBRARIES AND MUSEUMS There is compelling evidence that improved air quality reduces the rate at which damage occurs to cultural artifacts. This has led to the widespread introduction of temperature and humidity control systems, the increased use of particulate filtration, and in recent years the introduction of pollutant gas removal in HVAC systems. In drier areas with high ambient ozone levels activated carbon systems have been introduced, while in more humid areas with higher SO2 and NOx levels these pollutants are removed by water wash or impregnated alumina systems. At present, relatively few HVAC systems in museums have been designed for high removal efficiency for the primary pollutants: particulates, ozone, sulfur dioxide and nitrogen oxides. It does not appear that any are truly effective in removing NOx and fine particulates i.e. <&diameter; while most of the newer systems adequately remove ozone and SO,. Differing local pollution concentrations and environmental concerns coupled with differing philosophies of pollutant regulation have led to a range of proposed criteria. These have been tabulated by Baer and Banks (ref. 113). In a report recently prepared by the Committee on the Preservation of Historical Records, National Academy of Sciencest for the U.S. National Archives and Records Administration (ref. 2 ) a series of criteria intended specifically for the National Archives Building was prepared (Tables 3 and 4 ) . It is important to note that these criteria were intended for paper-based records and so would have to be modified for special collections, e.g. archaeological bronzes, photographic materials, lead artifacts, etc. Further, the inability of current systems to remove NO, adequately led to a vague specifications of "best available technology" for this pollutant. There is, in this reportt a significant emphasis on the removal of particulate matter. This is due to the

230

TABLE 3 . Recommended Standards for Paper-based Records in a Mixed Collection of Bound and Unbound Materials (standards to be met at the surface of the records).a'b

Relative Humidity

40-50%

I l p g m3 (0.4 ppb) best available technology

I 2)lg m3 (1.0 ppb)

03

a Specifications are averages over a 24 hour period. Small# short-term excursions outside these limits are permitted. After ref. 2 .

TABLE 4 . Draft ANSI Particulate Standards for Paper-based Documents in Libraries and Archives a System Filter Location

ASHRAE Weight Arrestance Efficiency

ASHRAE Atmospheric Dust Spot Efficiency

MIL-STD 282 DOP Efficiency

Pref ilterb

180%

230%

2 5%

Intermediate 195% FilterC

280%

250%

Fine FilterC

290%

275%

N.A.~

( a ) After refs. 3 and 18.

(b) For outside or makeup air. (c) For supply (both outside and recirculated) air. (d) N.A. denotes not applicable.

231

observation of Cass (ref. 2 ) that currently used filter systems are totally ineffective in removing the fine particulates that make up some 50% of the total mass load indoors. An important design strategy suggested is an emphasis on the environment experienced by the individual artifact so that increased attention to the design of display cases, book boxes and encapsulation methods is a priority for research and development. ACKNOWLEDGEMENT This work was supported in part by a grant from the National Endowment for the Arts. REFERENCES N.S. Baer and P.N. Bankst International J. Museum Mangement Curatorship1 4 , 1985r 9-20. National Materials Advisory Board, Preservation of Historical Recordsl National Academy Pressl 1986, Washington, D.C. chapter 3 . N.S. Baer and P.N. Banks, Pap. Proc. Ann. Meet-Air Pollut. Control ASSOC.~1985, 78, 85-8.8. J.F. Feenstrar Cultural Property and Air Pollution Damage to Monuments! Art-objects, Archives and Buildings Due to Air Pollutionr Ministry of Housing, Physical Planning and Environment, The Netherlands, 1984r 142pp. English Translation. J.E. Yocom and N.S. Baert in The Acidic Deposition Phenomenon and its Effects: Critical Assessment Review Papers, U.S. EPAi Washington, D.C. EPA-600/8-83-016BFr 19841 chapter E - 7 , section 7.1. J.E. Yocom, N . S . Baer and E. Robinson, in A.C. Stern (Ed.), Air Pollution, Volume VII Academic Press, New Yorkr 1986, chapter 4. R.W. Freyt The Library Journal, 57, 1932, 405-414. P. Brimblecomber JAPCA 26, 1976, 941-945. P. Brimblecomber Atmospheric Environment, 11, 1977, 1157-1162.

232

10 P. Brimblecombe, JAPCA, 28, 1978 I 115-118. 11 P. Brimblecombe, Notes and Records of the Royal Society of London, 32, 1978, 123-129. 12 J. Evelyn, Fumifugium, 1661. Facsimilie of the 1772 edition, Oxford, England, 1930. 13 C.L. Eastlake, M. Faradayr and W.S. Russell, "Report of the Commission Appointed to Inquire into the State of the Pictures in the National Gallery", House of Commons, May 24, 1850. 14 F.L. Hudson, Paper Technology, 8, 19671 189-190. 15 N.S. Baer and S.M. Berman, Restaurator. In Press. 16 E.E. Hughes and R. Meyersl Measurement of the Concentration of Sulfur Dioxide, Nitrogen Oxides and Ozone in the National Archives Building, NSBIR 83-27671 National Bureau of Standards, Washington, D.C. 1983. 17 S. Hackney, Studies in Conservation, 29, 1984, 105-116. 18 American National Standards Institute, American National Standard Practice for Storage of Paper-Based Library and Archival Documents, Draft Standard, 1985.

233

T.Schneider (Editor)/Acidificationand its Policy Implications

0 Elsevier Science PublishersB.V., Amsterdam - Printed in The Netherlands

EFFECTS OF ACID DEPOSITION ON CONSTRUCTION MATERIALS J.C.Th. HOLLANDER and R.W. LANTING TNO Division of Technology for Society, P.O. Box 217, 2600 AE (The Netherlands)

Delft

ABSTRACT Deposition of anthropogenic air pollutants causes significant incremental damage to economically important construction materials in addition to that caused by natural weathering. This paper discusses the effects of acidic air pollutants as well as those of other factors, such as material properties and climate, which are strongly interrelated with the former. Sulphur dioxide and its transformation products have been identified as the major active anthropogenic species in the atmospheric corrosion of metal structures and building stones. Economic damage due to increased costs of maintenance, repair and replacement are discussed in the second part o f this paper. Estimates of the costs for painted and galvanized steel, which have been identified a s the economically most important technical materials, range from an annual US $6 per capita in earlier studies to US $2 in more recent ones.

INTRODUCTION Materials exposed to the ambient atmosphere are subject to many environmental influences inducing deteriorative effects, such as corrosion

of metals, decay of building stones, and erosion and discoloration of paints. It has long been recognized that, in addition to natural environmental factors, air pollutants can accelerate the degradation of many types of materials. Recently, the role of acid and acidifying air pollutants has become the cause of considerable concern at both national and international level. This concern has centred mainly round the harmful effects associated with acid deposition, such as the die-back of forests, freshwater acidification in environmentally sensitive areas resulting in loss of fish stock, changes in the chemistry and biology of soils resulting in loss of elements essential for healthy vegetation, and serious damage to historical monuments involving the loss of aesthetic appearance. Corrosion and erosion of construction materials apparently plays a less noticable role in the concern

on acid deposition.

234 Today, there is a considerable body of literature describing the effects of air pollutants on construction materials as determined by both laboratory and field experiments. In most of these studies sulphur dioxide figures prominently and is at the same time the most frequently discussed representative of the acidifying air pollutants. If one considers the sheer volume of constructions exposed to the deteriorative effects of (acidic) air pollutants it is clear that even a small incremental damage to a unit material has a significant economic impact resulting from increased costs of maintenance, repair, replacement, or substitution by less sensitive (more expensive) materials. This line of

thought has

already

led

to considerable effort in the quantifi-

cation of air pollution damage to contruction materials in terms of economic costs. A reliable estimation of costs, setting the price of air pollution control against the benefit of the damage avoided, might be a powerful instrument in the hands of national and international policy makers. This paper discusses the effects of anthropogenic acidic air pollutants on construction materials known to be economically important. Thus, the discussion will be limited to the effects of the primary air pollutants, SO and NO and the sulphates and nitrates formed from them, toge2 ther with the asso:iated H'ion. Although it is recognized that the complex atmospheric (photo-) chemistry of oxides of nitrogen and hydrocarbons plays a key role (as the driving force) in the conversion of the primary pollutants SO2 and NOx

into theiracids through the

production of hydroxyl radicals, hydrogen pe-

roxide, and ozone, this point is only mentioned here and not further elaborated. IMPACT MECHANISMS The atmospheric deterioration of materials is a very complicated process that involves the physical and chemical nature of the materials as well as environmental factors. The latter can be divided in climatological factors or more specifically

the micro-climate around objects and factors

related to the chemical and physical properties of both natural and anthropogenic air pollutants. Deposition processes The first step in the mechanism of deterioration of any material by air pollutants obviously is their transport to the surface of the material,

235 a process generally described as deposition of air pollutants. This process includes both the supply to a surface of pollutants dissolved in rain water (wet deposition) and of gaseous and particulate air pollutants in the absence of rain (dry deposition). The effects of wet deposition are difficult to assess owing to the event-like nature of precipitation, its varying intensity, and complex interaction with the exposure history of materials. With respect to the event-like nature of precipitation it must be noted that the data on concentrations of acidic species in rain water have been and still are mainly based on long term integrating sampling techniques and do not provide data on the flux of pollutants during a single event. The main acidic species supplied by wet deposition are hydrogen ion and sulphates and nitrates formed by atmospheric tranformation of the primary pollutants

SO2 and NOx during their transport through the atmosphere from their source areas to remote and relatively unpolluted areas. Wet deposition is therefore considered to contribute substantially to the deposition flux of pollutants in such areas. Dry deposition of air pollutants is a complicated process described by a parameter called deposition velocity, which is simply the ratio between the flux o f a pollutant to a material surface and its concentration. This parameter is by no means a constant, but depends on material properties, climate factors, and chemical and physical properties (particulate, gaseous) of the individual pollutant. It has been emphasized recently that these dependencies must be borne in mind when relating deterioration rates obtained from field experiments to concentrations of air pollutants (ref 1,2).

In theory, monitoring of air pollutant deposition fluxes would be

more relevant with respect to atmospheric deterioration rates, however, especially in the case of gaseous air pollutants, data for air pollutant concentrations are more abundantly available and can be readily used to derive necessary emission reductions. The main acidic species in dry deposition are the primary gaseous air pollutants SO2 and NO

and their

conversion products, gaseous nitric acid and particulate sulphuric acid, sulphates and nitrates. Since, unlike wet deposition, dry deposition is continuous and since the deposition flux is proportional to the concentration of an air pollutant, it is the dominant process in areas close to sources of primary air pollutants. These are generally urban and industrial areas where the majority of sensitive and economically important materials are located. The relative importance of wet and dry deposition of air pollutants containing sulphur is illustrated in Table 1 by data taken from Beilke (ref. 3 ) .

236

TABLE 1 Relative importance of wet and dry deposition of sulphur containing species (long-term average), simplified from Beilke (ref. 3 ) .

Degree of air pollution

% Removal of sulphur by wet deposition

% Removal of sulphur by dry deposition

Polluted regions SO2: 50 pg.w3

10-20

80-90

Moderately polluted

15-25

75-85

Unpolluted regions so2: 1-10 p g . w 3

35-65

35-65

Large European region

35-50

50-65

Although these data are uncertain (ref. 3 ) , mainly owing to the difficulty of quantifying dry depostion processes, they illustrate the general trend that dry deposition is responsible for the removal from the atmospher of some two thirds of the sulphurous pollutants it contains, at least in the long term and over a large budget area. For NO

and its con-

version products the relative contributions of wet and dry deposition are less easy to ascertain, partly because less is known about their dry deposition behaviour, and partly because the relationships between the concentrations of NO and NO

2

and their conversion products are more complex

(ref. 3 ) . The problem of the relative contributions of wet and dry deposition is closely related to that of contributions from local or remote sources to the deposition of air pollutants. Its solution is very important for the design of an effective abatement strategy that mitigates the effects of acid pollutants on materials as well

as

other harmful effects of acid de-

position. Material properties The size of an object or structure, as well a s its shape and surface roughness determine the characteristics of the boundary layer of air surrounding it, and with it the aerodynamic resistance to transfer of pollutants from the atmosphere to its surface (ref. 2 ,

4 , 5).

Lipfert and

Wyzga (ref. 4 ) calculated deposition velocities for structures (or structural elements) of various sizes, and found a dramatic increase by more

237 than one order of magnitude for objects of small diameter (fence wire, 0.001 m diameter) as compared to objects of large diameter (storage tank, 10 m diameter). They also point to the pitfalls in applying corrosion rate

data from small test plates to objects that are greatly different in size leading to possible biases of a factor of 3 or more in the estimated physical damage. Design and geometry of objects determine to a large extent the degree of accumulation of water and salts, and thus the degree of interaction with the material of adsorbed and absorbed pollutants. Surface texture is also an important factor in the absorption of pollutants. Porous materials absorb more pollutants and moisture than do non-porous materials. Weathering may increase the roughness of a surface, and so cause deposition and absorption of pollutants to increase. The chemical properties of an exposed surface can increase the resistance to transport of pollutants beyond that governed by aerodynamic factors. Slow reaction rates or diffusion processes on the surface decrease the dry deposition rate. Important porous materials such as concrete, mortar, and cement rendering all have alkaline properties which make them perfect sinks for acid pollutants. Sulphur dioxide is rapidly adsorbed on wet zinc surfaces, but on a perfectly dry zinc surface the deposition rate falls to zero when a monolayer of adsorbed SO2 has built up (for which an exposure dose of roughly 25 pg.m3.h is needed) (ref. 6 ) . Climatic factors Relative humidity is the most important variable affecting atmospheric corrosion. Temperature and relative humidity govern the formation of a water film on the material surface. Since water is necessary as a medium for chemical reactions to proceed, the time the surface is wet is an important factor. Moreover, the example of the deposition of SO

2 On

zinc in the previous section shows that surfaces only absorb pollutants in significant amounts when the surface is wet. The time during which a water film is present on a surface is called the time of wetness, operationally defined as the time a certain critical value of the relative humidity is exceeded. This critical value depends slightly on the nature of the material (ref. 1).

The presence of hygroscopic corrosion products and

hygroscopic salts deposited on the surface may decrease this critical value, and so lengthen the time of wetness. The presence of water on a surface is a more or less periodic event causing the corrosion process to proceed discontinuously. The time of wetness depends on the prevailing climate and may range from 20% to well over 60% of real time.

238

A specific case is the formation of dew. Compared to rain precipitation the amounts of water deposited during a dew period are only minor (about 0.05 ml.cm-2, corresponding to 0.5 mm of precipitation).

In com-

bination with the preceding dry deposition of acids and acid forming species this can lead to a very strongly acidic environment on the receptor surface. Under these conditions an almost stoichiometric reaction of the acid with the surface material will take place (ref. 6 , 7 ) . Rain also causes wetting of surfaces, but the effects of precipitation on the corrosion process go much further. They depend both on its intensity and its chemical composition. In the case of non-porous surfaces, a drizzle o r light shower of short duration promotes attack of materials by wetting the surface and bringing corrosive agents dissolved in the precipitation to the surface. Heavy and longer lasting precipitation events may have the main effect of diluting and washing away such agents and corrosion products, so decreasing the corrosion rate. When the corrosion resistance depends on the presence of protective layers of corrosion products, as in the case of metals, dissolution of these products increases the corrosion rate. The solubility of metal oxides, hydroxides and carbonates increases strongly at pH values less than 4 . Metals like zinc and copper are therefore sensitive to precipitation with a low pH. The processes described above show that the effects of rain strongly interact with those of the deposition preceding the rain event. The main damage caused by rain to porous materials arises from the uptake of large amounts of (polluted) water by capillary action, and the ensuing secondary effects due to hydration and crystallization of migrating salts with moisture as the driving force. The microclimate in the immediate vicinity of objects can differ markedly from the general macroclimate. Changes of the wind velocity profile have already been mentioned. In densely built-up urban areas, the so-called heat island effect strongly influences the time of wetness. Air pollutants Natural pollutants of importance i n material deterioration are carbon dioxide, chloride ion, small amounts of naturally occuring other ions, and dust from natural sources. The main effect of carbon dioxide on cementitious stone material is the formation of calcium carbonate (carbonation),

with simultaneous re-

duction of the alkalinity of the stone matrix. It also reacts with metal hydroxides to form metal carbonates, which are more easily leached out of the protective corrosion layer by highly acidic rain. Although a natural

239

constituent of the atmosphere, significant anthropogenic emissions of carbon dioxide occur in urban and industrial areas. Chlorides contribute to the electrochemical corrosion of painted and bare metals. When penetrating the carbonation zone of concrete, they may initiate corrosion of the reinforcing steel. Chlorides can also react with sulphuric or nitric acid to form highly corrosive hydrochloric acid. I n coastal and marine environments the main source of C1- is sea spray.

The Dutch marine climate and the concentration of large industrial and urban centres with a significant stock of materials in a narrow zone parallel to the coast make chloride one of the dominating factors in atmospheric corrosion of economically important groups of materials. Another important source of chloride is the intensive use of de-icing salts on roads. Hydrochloric acid and chlorides are also emitted in the burning of household refuse and coal with a high chloride content. The main soiling o f

effect of re-entrained

dust form natural sources is the

surfaces. However, interaction of gaseous air pollutants and

deposited dust may lead to local formation o f agressive species causing pit corrosion, as in the case of aluminium. On the other hand, a dust deposit may shield a surface f r o m acid pollutants, especially when it is (slightly) alkaline (ref. 8). The major anthropogenic air pollutants causing damage to construction 2materials are SO2, NO2, and their oxidation products SO4 and NO- and the 3’ + . H ion. These acidic air pollutants accelerate the natural weathering processes. Damage from deposition of acidic air pollutants either dry or wet is generally indistinguishable from damage caused by the natural phenomena, although this is precisely what is needed if an effective abatement strategy is to be undertaken. In addition, the strong interaction between natural factors and anthropogenic air pollution makes it very difficult to demonstrate and quantify the specific contributions of (individual) anthropogenic acidic air pollutants. The effects of acidic deposition on materials have been studied under both laboratory and field conditions. Controlled exposure of materials in the laboratory offers the advantage that the specific effects of a single pollutant or environmental factor can be isolated. However, to produce measurable damage in a reasonable time, the material often has to be exposed continuously to extremely high pollutant concentrations. Moreover, the complex synergism or antagonism of environmental factors and pollutants makes it difficult to reproduce realistic conditions. Nevertheless, laboratory experiments are of great help in elucidating the mechanisms of deterioration, and establishing

240 fundamental data on reaction stoichiometry and deposition velocities. Edney et al. (ref. 6 , 7),

in a series of very elegant experiments with gal-

vanized steel samples, have recently demonstrated the power of experiments in advanced computer-programmed environmental chambers, allowing for more realistic conditions, combined with chemical analysis of dew produced by chilling test samples, instead of measuring physical damage. Field studies involve the exposure of materials to ambient atmospheres representing various combinations of pollutant concentrations and other environmental factors. Statistical analyses of physical damage as a

function of pollutant concentrations and other environmental factors

afford

functional relationships between these factors, and may be used

to predict damage

from known concentrations and envirclmental factors

for other locations. The major disadvantages of this approach include the difficulty of isolating the effect of a single pollutant owing to its interaction with other variables (covariance of pollutant concentrations), and the restricted number of variables that can be monitored, which may lead to effects being attributed to the wrong variables. Monitoring that does not cover all relevant variables is likely to be responsible for much of the unexplained variance in statistical data and, consequently, for the lack of predictive power of the exposure-response relationships derived from them. I n order to judge the results of statistical analyses of field data,

it is necesary for the functional forms of the exposure-response relationships (relating physical damage to pollutant concentrations) to be

so

for-

mulated that they reflect the mechanism of the deterioration process. I n this way at least some of the coefficients obtained can be compared to theoretical values calculated on the basis of dry deposition velocities, reaction stoichiometry, and other known details of the deterioration process. Several samples of this type of analyses have recently been published (ref. 1 , 5 , 8). Sulphur dioxide figures prominently among damaging acidic air pollutants, followed by the wet and dry deposition of secondary pollutants , ' H (

SO:-,

NO-). 3

Field studies have revealed no effects of sulphate aero-

sols. Their deposition velocity is much lower than that of S O 2 . For NO 2

interactions (NO is estimated to play a less important role) o n l y limited evidence is available. However, there is a significant lack of NO2 (NOx) measurements in most exposure programmes. Laboratory experiments (ref. 7) have shown that the dry deposition velocity of (gaseous) nitric acid, which is highly corrosive, on zinc is comparable to that of S O 2 . Its presence and formation in the atmosphere are still not well known.

241 DAMAGE TO SPECIFIC CONSTRUCTION MATERIALS From an economic point of view, the most important construction materials

at risk from acidic deposition are painted and unpainted metals.

Building stones on a cementitious base, like concrete and mortar, come second, but their susceptibility to attack by pollutants crucially depends on their formulation and quality. Unprotected carbon steel Unprotected

carbon steel is very

sensitive to

corrosion and has

been well studied. It is, however, normally given a protective coating, and s o is not further discussed in this paper. Zinc

~

Zinc is technically very important and mainly used to protect steel (galvanized steel).

Zinc corrosion has been studied in numerous field ex-

posure programmes, and a wide variety of exposure-response or damage functions is available. I n a recent study Lipfert et al. (ref. I ) tried to reconciliate damage functions by analysing the data bases of 8 exposure programmes in the US, Canada, Western and Eastern Europe with a total of

72 exposure sites. A damage function was derived not only from a purely statistical treatment of the data, but also from current knowledge o f the corrosion mechanism. The result of the statistical analysis was judged by comparing the derived coefficients with theoretical ones calculated from the stoichiometry of the SO -Zn reaction and deposition velocity during 2

time of wetness (RH above 8 5 % ) . Hence the function reflects typical mechanistic effects of the corrosion process. This damage function makes it possible to look at the effect of acid precipitation versus dry deposition o f SO2. Figure la shows the calculated corrosion rates as a function of the concentration of SO2 for various pH values (fraction of time wet: 0 . 3 5 ; precipitation: 1000 nun year-'). There is a strong increase of corrosion for pH values below 4 . 5 , corresponding to the increasing solubility of the protective layer of natural corrosion products

(zinc hydroxide and carbonate).

Note also the

fourfold increase of the corrosion rate at zero SO2 concentration when the pH decreases from 5.6 to 3 . 5 . The slight increase of the slope with decreasing pH points to a synergism between the effects of SO2 and H'. Due to the removal of the protective layer by H+ the SO

2

attack zinc more directly, increasing the corrosion rate.

deposition will

242 PH

35

LO LS

SO 56

20

notliroi factors

I

0

I

I

I concentration

Fig. as a Fig. rate

soz

a -

~ p m-31 g

b Concenlrohon

802 l p g m-31

la. Corrosion rates of zinc (4-year average) for different pH values function of ambient SO concentrations. Ib. Relative contribAions of SO and H+ (pH = 4 . 2 ) to the corrosion of zinc as a function of ambient S 8 , concentration. Figure lb shows the relative contributions, calculated from the same

damage function, of H+, SO

2

and natural factors (including effects of un-

specified pollutants) to the corrosion rate of zinc at a rain pH of 4 . 2 (representative for Central Europe). SO2

It shows that at an annual average

concentration of 10 ~ g . m - ~the , combined effect of SO2 and H+ is of

the same magnitude as that of natural factors. At higher SO2 concentrations the effects of SO2 rapidly begin to dominate those of H+. Hence, the overall effect in unpolluted areas is mainly due to wet deposition of H+, whereas in polluted areas rhe main affect is caused by dry deposition of SO

2'

The role of NOz was not assessed in Lipfert's study (ref. 1 ) . A conservative estimate (ref. 5 ,

7)

on

basis of its deposition velocity and stoichiometry

indicates that its effect o n zinc is at least a factor four

less than that of SO2. Painted steel Reliable damage functions for present day paint formulations are not available. Apart from natural factors such as chloride and W radiation, SO2, 03, NOz

and dust are suspected of interacting. Shortened lifetimes are

often attributed to deposition of pollutants between the pretreatment and painting of an object resulting in uncercutting by rust and loss of adhe-

243 sion.

Other p r o c e s s e s a r e t h e p e n e t r a t i o n o f t h e p a i n t f i l m by c o r r o s i v e

agents a t

s i t e s where t h e l a y e r i s t h i n .

E x i s t i n g damage f u n c t i o n s f o r

p a i n t a d d r e s s o n l y e r o s i o n o f t h e p a i n t f i l m a s p h y s i c a l damage p a r a m e t e r . T h i s can o n l y p a r t l y e x p l a i n t h e o b s e r v e d damage i n r e a l l i f e . Cementitioiis m a t e r i a l s There i s much concern a b o u t a t y p e of damage t o r e i n f o r c e d c o n c r e t e that

i s commonly

referred

to

as

concrete disease.

The

high a l k a l i n i t y

o f t h e cement m a t r i x p r o t e c t s t h e r e i n f o r c e d s t e e l from c o r r o s i o n i n w e l l made c o n c r e t e . The main p r o c e s s l e a d i n g t o l o s s of a l k a l i n i t y and hence t o corrosion of steel involves When t h e s u r f a c e l a y e r ,

r e a c t i o n w i t h C 0 2 and i s c a l l e d c a r b o n a t i o n .

c o v e r i n g t h e s t e e l , i s t h i c k enough, a c i d p o l l u -

t a n t s w i l l o n l y c a u s e t h e f o r m a t i o n o f s o l u b l e and i n s o l u b l e s a l t s , which a r e l e a c h e d o u t o r washed away by a c i d p r e c i p i t a t i o n c a u s i n g t h e s u r f a c e t o become e t c h e d . enough,

the

If,

o n t h e o t h e r hand,

carbonation

layer w i l l

reach

the surface layer i s not t h i c k the

r e i n f o r c e d s t e e l and

the

p a s s i v a t i o n o f t h e s t e e l w i l l b e l o s t . C h l o r i d e s , and t o some e x t e n t n i t r a t e s as w e l l , c o r r o s i o n of

a r e a b l e t o p e n e t r a t e t h e carbonation zone, so i n i t i a t i n g

t h e s t e e l . The voluminous c o r r o s i o n p r o d u c t s of s t e e l c a u s e

c r a c k s , which l a y t h e embedded s t e e l more open t o a t t a c k by SO 2' R e i n f o r c e d c o n c r e t e i s a t y p i c a l example of an o t h e r w i s e r a t h e r durable

material

that

p o l l u t a n t s through such

can b e

rendered very

susceptible

faulty building practices.

complex p r o c e s s e s no

damage

t o a t t a c k by a i r

I t w i l l be c l e a r t h a t f o r

functions are yet

available,

and

are

very d i f f i c u l t t o develop. S t r u c t u r e s immersed i n s o i l o r w a t e r E f f e c t s of d e p o s i t i o n of a c i d i c a i r p o l l u t a n t s a r e noted i n a l l t h r e e compartments of

t h e ecosystem, v i z .

air,

s o i l and w a t e r .

S t r u c t u r e s em-

bedded i n s o i l o r immersed i n w a t e r will s u f f e r i n d i r e c t e f f e c t s of a c i d i f i c a t i o n o f t h e s e media. Burried

concrete foundations,

ducts,

s t e e l t a n k s and l e a d j a c k e t e d

c a b l e s a r e a t r i s k when t h e pH o f s o i l f a l l s below 5 . A

well-known

problem caused by a c i d i f i c a t i o n of ground and s u r f a c e

w a t e r i s t h e i n t e r n a l c o r r o s i o n of p i p e s t r a n s p o r t i n g d r i n k i n g w a t e r i n a r e a s where

this

water

is

c o n t a m i n a t i o n w i t h s a l t s of lead t o health effects.

not

t r e a t e d t o a d j u s t t h e pH.

lead,

The r e s u l t i n g

c o p p e r , cadmium o r z i n c may e v e n t u a l l y

ASSESSMENT OF ECONOMIC DAMAGE Cost-benifit analysis, in which the total costs of proposed scenarios for emission abatement are set against the benefits (in terms of avoided damage), is increasingly used to assist in making policy decisions. For assessing economic damage from air pollution there are essentially three basic approaches. The first, or physical damage approach, is based on established exposure-response relationships or damage functions. The second, or market approach, assesses for areas with different pollution levels the demand for services and goods, sensitive to damage by air pollutants, or the costs of maintenance and repair. The third, or non-market approach, estimates the willingness o f the public at large to pay for any improvements in the environment. The two last mentioned approaches fail to single out the damage caused by an individual pollutant. The physical damage approach does have this capability, and is the most

straightforward

for construction materials.

On basis o f critical damage levels, the physical damage derived from the damage functions is translated into changes in useful lifetime

of ma-

terials at risk. The cost of incremental maintenance, repair and replacement is used to convert physical damage into monetary terms. This approach requires a great deal of data, which may not always be available. To mention some of the problems: Most dispersion models

for predicting air quality and deposition

fluxes are not able to assess the actual exposure regime of objects in built-up areas such as cities. Damage functions are derived from exposure of small specimens in the field and may not be representative for what actually happens to a real building (e.g. the microclimate is quite different). Moreover, no reliable damage functions are available for many important materials such as painted metals and stone. Considerable uncertainty is also introduced by assumptions on maintenance, repair and replacement strategies (ref. 9). Hence, most estimates of economic damage are subject to large errors which, regrettably, are not always taken into account when making costbenefit analyses. However, if economic damage is expressed as a probability distribution, an approach now adapted by the United Nations Economic Commission for Europe, such estimat.es are valuable tools in decision making.

245 The e c o n o m i c a l l y most i m p o r t a n t c o n s t r u c t i o n materials a r e p a i n t e d and g a l v a n i z e d s t e e l c o n s i d e r i n g t h e w i d e s p r e a d u s e and s e n s i t i v i t y t o a t t a c k by a i r p o l l u t a n t s . Many a s s e s s m e n t s of damage by SO2 were made i n t h e s e v e n t i e s f o r t h e s e materials ( T a b l e 2 ) . TABLE 2

E s t i m a t e s of t o t a l c o s t s from damage t o m e t a l s and p a i n t e d m e t a l s ( c o r r o s i o n and p r o t e c t i o n ) due t o a i r p o l l u t i o n .

Country

USA USA USA *b sw )

NL

OECD ( l l ) b )

Base year

Materialsa)

1970 1970 1970 1970 1970 1970 1974

1, 2 1, 2 1 1, 2 1 , 2, 4 1, 2, 3 1, 2

Pollutant

CostC)

US $ / c a p i t a .

annum (1980) all

13.8 3.8

3

N

USA ( c a s e study)

a) b) c)

1978 1979 1985

ai?

so so2 so;

SO2

11 12 13 14 15 16

5.2

1 , 2, 3 1, 2 1

10

3.1 5.4 9.0 4.5

mean 6.4, s d

NL

Ref.

H+

3.7

1.0 17 3.1 18 2.6 (1985) 19 mean 2 . 2 , sd 1 . 1

1 = galvanized steel, 2 = painted steel, 3 = painted galvanized steel 4 = p a i n t e d wood

on b a s i s o f c o s t s s a v i n g s f o r maximum r e d u c t i o n o f e m i s s i o n s a p p r o x i m a t e c o n v e r s i o n on 1980 p r i c e s b a s e d on consumer p r i c e i n d e x f o r t h e USA. None o f t h e s e s t u d i e s h a s a f f o r d e d f u l l y s a t i s f a c t o r y r e s u l t s , mainly

owing t o t h e l a c k of r e l i a b l e damage f u n c t i o n s f o r p a i n t e d s t e e l . The est i m a t e s around 1970 v a r y b y a f a c t o r o f 3 t o 4 w i t h a n o v e r a l l a v e r a g e v a l u e of US $ 6 (1980) p e r c a p i t a p e r annum. S t u d i e s around 1980 i n d i c a t e a damage of r o u g h l y $ 2 (1980) p e r c a p i t a p e r annum. T h i s a p p a r e n t d e c r e a s e i n damage c o s t s i s due on one hand t o t h e c o n c u r r e n t r e d u c t i o n of ambient

SO

c o n c e n t r a t i o n l e v e l s a n d , on t h e o t h e r , t o a more c r i t i c a l u s e o f da2 mage f u n c t i o n s f o r p a i n t . F o r o t h e r c o n s t r u c t i o n m a t e r i a l s , s u c h a s s t o n e s and p a i n t e d s u r f a c e s , damage e s t i m a t e s a r e h i g h l y u n r e l i a b l e , b e c a u s e t h e e f f e c t s o f a c i d d e p o s i t i o n can n o t b e s e p e r a t e d from n a t u r a l phenomena.

246

ABATEMENT STRATEGIES Abatement of the adverse effects of air pollutants on materials is usualy effected along two independent routes, with different control levels. At the administrative level, improvement of air quality by reduction of emissions is the major route, whereas at the manufacturing or consumer level, the improved pollution resistance of the material itself, the aim of many industrial exposure programmes, is pursued. With respect to pollution control, SO and its transformation products are the main anthropoge2 nic agents in the atmospheric corrosion of metal structures and building stones. The contribution of NO2 has not been resolved for all technical materials. At current concentrations of SO2 and NO2 the dry deposition of

NO

2

is estimated to be responsible for far less than 20% of the damage

caused to metals by SO2 (ref. 5 , 7, 2 0 ) . The interaction between wet acid deposition and the film of passivating corrosion products on a metal suggests that the relationships between exposure and effect are not linear, even for a relatively simple system like zinc. However, it is obvious that .any reduction in acid generating pollutants will reduce the economic damage to materials. In deciding control strategies distinction must be made between longrange transport of air pollutants and local pollution. Figure la shows that any further increase in rain acidity is likely to increase the corrosion rate of zinc, particularly in rural areas, where the relative contribution of H+ is high. On the other hand, urban and industrial areas contain a high density of sensitive materials,

so

most of the harm will be done by

local pollution sources provided that these have low emission heights. Control of local emissions is therefore likely to yield the highest benefits in terms of avoided damage to materials. The desirable degree of abatement depends on what physical or economic damage is considered acceptable. Cost-benefit analyses based on damage functions may assist in deriving the opfimum solution. Whereas the above mentioned line opts for a better environment the second line seeks to improve the pollution resistance of materials. This approach can be quite cost-effective. Educated guesses supported by construction engineers state that roughly one quarter of the damage caused by atmospheric corrosion could be avoided by simple actions such as better design, proper material selection and application of

improved quality

control.

247 Apparently the use of new materials and building practices caused to a large extend the loss of century old awareness and craftmanship with respect to avoidance of atmospheric degradation processes of building materials. Since the present knowledge, often atquired by bitter experience, is only fragmentary disseminated in the building and construction trade, effort should be made to integrate this knowledge, leading to better guidance with respect to the prevention of atmospheric corrosion by receptor oriented measures. CONCLUSIONS AND RECOMMENDATIONS The process of atmospheric degradation is a complex phenomenon governed by many interrelated factors of which air pollution is only one. Attempts to quantify the individual contributions of acidic air pollutants were initially centred on the dry deposition of SO2, and have more recently included the role of wet deposition o f H+

ions. For lack of

field monitoring data, the contribution of NOx cannot as yet be fully quantified. Damage functions are still highly empirical, with a recent tendency to incorporate physico-chemical relationships in the design of the functional form. There is not enough knowledge available to develop purely theoretical damage functions from first principles, using the appropriate physico-chemical relationships only. The use of air pollutant concentrations as the main variables in damage functions requires a large research effort in monitoring and investigation of factors affecting the relationships between concentration and deposition flux. An alternative would he to improve methods of measuring deposition fluxes of acidic air pollutants. Current damage functions for painted objects and stone are only partly able to describe the total damage processes. They do not take into account influences such as variations in thickness and permeability of the paint layer and' in the porosity of stone. Most estimates of economic damage show large uncertainties, accumulated from several factors such as: the extrapolation of damage observed on small test samples to real objects or constructions, absence of reliable damage functions describing the full damage, uncertainties in assumptions on maintenance, replacement and substitution strategies. It is obvious that any reduction in acid generating pollutants will reduce the economic damage to materials. However, more knowledge is needed

248 on the relative contributions of local versus remote sources and related topics, to judge the effectiveness of emission control scenarios. Since much damage to structures can be avoided by design modification, proper material application and improved quality control, these options should also be incorporated in cost-benefit analysis. The assessment of the effectiveness of protective treatment, when damage is already done or when protection cannot wait for improvement of air quality remains still an important research area. REFERENCES 1.

2. 3. 4. 5. 6.

7. 8. 9.

10. 11.

12. 13. 14. 15.

16.

F.W. Lipfert, M. Benarie and M.L. D a m , Derivation of metallic corrosion functions for use in environmental assessment, Brookhaven National Laboratory report, Brookhaven, 1985. F.H. Haynie, in P.J. Sereda and G.G. Litvan (Eds.), Durability of Building Materials and Components, ASTM STP 691. American Society for Testing and Materials, 1980, pp. 157-175. S . Beilke, Acid deposition, un updated review on atmospheric physicochemical aspects of the acid deposition problem in Europe, Commission of the European Communities, 1985. F.W. Lipfert and R.E. Wyzga, Application o f theory.to economic assessment of corrosion damage, presented at ACS Symposium on Degradation of Materials due to Acid Rain, Arlington, Virginia, 1985. F.H. Haynie, in S.W. Dean, Jr. and E.C. Rhea (Eds.), Atmospheric Corrosion of Metals, ASTM STP 767, American Society for Testing and Materials, 1982, pp. 286-308. E.O. Edney, D.C. Stiles, J.W. Spence, F.H. Haynie and W.E. Wilson, Atmospheric Environment, 20 (1986) 541-548. E.O. Edney, D.C. Stiles, J.W. Spence, F.H. Haynie and W.E. Wilson, in press. F.H. Haynie, Environmental factors effecting the corrosion of weathering steel, presented at ACS symposium on Degradation of Materials Due to Acid Rain, Arlington, Virginia, 1985. A.R. Stankunas, E.F. McCarthy and J.E. Yocom, Uncertainties in estimating the effects of air pollutants on materials, Proceedings of the 7 5 t h Annual Meeting of the Air Pollution Control Association, New Orleans, 1982. F.W. Fink, F.H. Buttner and W.K. Boyd, Technical-economic evaluations of Air Pollution corrosion costs on metals in the US., Batelle Memorial Institute Columbus, OH, report PB 198453, 1971. D.G. Gilette, Sulphur dioxide standards and material damage, J. Air Pollut. Control A s s o c . , 25 (1975) pp 1238. B.C. Liu and E.S. Yu, Physical and economic damage functions for air pollutants by receptors, Report EPA 600/5-76-011, 1976. P.M.C. Jones, An economic and technical appraisal of air pollution in the United Kingdom, Programme Analysis Unit, PAU, Berks, 1972. V. Kucera, Ambio, 5 (1976) 243-248. H.M.A. Jansen and A.A. Olsthoorn, Economische waardering van de nationale schade door luchtverontreiniging. Moza'iek van de milieuproblematiek. Report Instituut voor Milieuvraagstukken, W, Amsterdam, 1982.

OECD, The cost and benefits o f sulphur oxide control, OECD, Paris, 1981.

249

17. A.A. Olsthoorn, Schade aan materialen door SO Werknota 117, Instituuh voor Milieuvraagstukken, W , Amsterdam, 1 6 5 . 18. J.F. Henriksen, S . Haagenrud and F. Gram, The effect on atmospheric corrosion costs of a requirement for oils with a low-sulpur content, report NILU, 1979. 19. F.W. Lipfert, L.R. Dupuis, R.G. Malone, J. Schaedler and M.L. D a m , A case study of materials damage due to air pollution and acid rain in New Haven, CT, presented at Second U . S . Dutch International Symposium: Aerosols, Williamsburg, VA, 1985. 20. R.W. Lanting, Deterioration of materials by NO (in Dutch), Ministerie van Volkshuisvesting, Ruirntelijk Ordening 'en Milieubeheer, Publicatie reeks Lucht 1 2 , 1983.

T. Schneider (Editor)/Acidificationand its Policy lmplicatiom

251

0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

ACIDIFICATION AND DRINKING WATER

-

GROUNDHATER

Ulf von Bromssen The National Swedish Environment Protection Board, P 0 Box 1302, 171 25 Solna (Sweden)

ABSTRACT The atmospheric load of acids exceeds the base production by weathering of non-carbonate rocks and soils in many parts of Europe. This has resulted in changes in the quality of drinking water from groundwater wells. A national well survey in Sweden together with an investigation of the penalty for corrosion of indoor water installations has revealed substantial costs of 150 M SEK per year for water damages caused by corrosion due to acidification. An estimate based on a municipal well survey of 10,000 private wells has revealed a government expense of 500-1,000 M SEK for alkalizing private well water. As a result the Swedish government has allocated funds for a trial period for subsidies for countermeasures to private wellowners with acid, corrosive drinking water. INTRODUCTION The quality of drinking water from groundwater supplies has changed in many countries in Europe since the 1950s. Changes influenced by acidification may be caused by atmospheric deposition, by nitrogen fertilizing in farming and/or changes in land use. This paper presents the effects and economical consequences of drinking water influenced by atmospheric deposition and countermeasures taken in Sweden. A presentation of atmospheric acid loading and base production from weathering of silicate 'minerals and effects of acidfication in the Nordic countries will be made. The changes o f w 7 1 water quality in the last decades will be discussed. GENERATION AND DEPLETION OF ALKALINITY - THE ACIDIFICATION BUDGET Long-term changes of the groundwater quality will occur if the total acid load exceeds the base production from weathering of soils and rocks. The atmospheric load of acids from sulfate and nitrogen compounds ranges from 0.1 keq/ha,yr in northernmost Sweden to 1 . 5 keq/ha,yr in southern Scandinavia and 3-7 keq/ha,yr in the most exposed areas of Central Europe. (ref. 2 ) The extension of slowly weathering rocks in Europe i s presented in fig 1 and pH in precipitation over Europe in fig 2.

252 Base p r o d u c t i o n o f bicarbonate from weathering o f a c i d i c and intermediate a c i d i c rocks, i.e.granites, o f 0.1-2.0

keq/ha,yr,

a c i d deposition.

gneisses, sandstones and q u a r t z i t e s i s i n the range

which i n many cases i s l e s s than base consumption by t o t a l

T h i s w i l l r e s u l t i n a c i d i f i c a t i o n of groundwater over time.

F i g . 1 . A c i d i c and i n t e r m e d i a t e a c i d i c h a r d rocks, i .e .granites, gneisses, sandstones, q u a r t z i t e s i n p a r t o f Europe. -

Fig. 2. pH i n p r e c i p i t a t i o n over p a r t o f Europe. (ref.12)

Weathering o f carbonate rocks and soils produces a l k a l i n i t y i n t h e

4-16 keq/ha,yr.

order o f

T h i s i s o f t e n more t h a n consumption by a c i d load. The e f f e c t s

on groundwater is increased a l k a l i n i t y , hardness and s u l f a t e c o n t e n t and eventua l l y increased c o n t e n t o f n i t r a t e . Atmospheric loads o f a c i d s and base product i o n p o t e n t i a l i n d i f f e r e n t p a r t s o f Europe a r e presented i n Table 1. TABLE 1 Average y e a r l y atmospheric l o a d of a c i d s and t h e base p r o d u c t i o n p o t e n t i a l from s i l i c a t e and limestone weathering i n d i f f e r e n t p a r t s o f Europe. ( r e f . 2 ) Sulfur Wet + Dry g/m2

Sulfur + Nitrogen keq/ha

HCOg-Prod from Weathering S i 1 ica t e keq/ ha Limes tone keq/ ha Extreme Normal

N Scandinavia C Scandinavia and Scotland

0.2

0.1

0.1-0.4

0.4-2

4-16

1 .o

0.6

0.1-0.4

0.4-2

4-16

S Scandinavia

2.0

1.3

0.2-0.4

0.4-2

4-16

C e n t r a l Europe

5-10

3.7

0.2-0.4

0.4-2

4-16

253

<

Alkalinity production at shallow soil depths 4 m,may be in the range of 0.1-0.4 keq/ha,yr for sand and glacial till if the minerals lack calcium carbonate. For greater depths the base production may be 0.4-2 keq/ha,yr. In Sweden the median depth of private dug wells is 4.1 m and for drilled wells in hard rocks 68 m. Dug wells are performed in glacial till or in sandy soils. Critical load for acid deposition for shallow groundwater may be in the range of 0.2-0.4 keq/ha,yr for glacial till and 0.1-0.2 for sand. The acidification budget for different parts of Sweden can be studied in fig 3.

0.15 base consumption by atmospheric acid deposition 0.3

base production potential by weathering 0.1-0.4

Fig. 3. Base production potential in non-calcareous 0-4 m deep soils and base consumption by wet and dry atmospheric acid deposition, keq/ha,yr. GEOLOGY AND THE WATER SUPPLY STRUCTURE IN THE NORDIC COUNTRIES CONTRIBUTE TO THE EXTENT OF ACIDIFICATION OF OUR WATER SUPPLIES Acidification o f groundwater by acid rain i s mainly a phenomenon in areas with slowly weathering hard rocks and soils, and where drinking water is drawn from shallow wells. Areas with acidic or intermediate acidic hard rocks are shown in figure 1 . Apart from Northern Europe, such geological conditions are found in several areas in Central Europe, where acid deposition is also high. Figure 2 shows pH in precipitation over Northern Europe. As the weathering rate is considered to be independent of pH in the range pH = 4.0-7.0, weathering becomes a function of the transit time for water in the soil or rock. This means that water from shallow wells and water with short transit time in the basin-aquifer will first become affected by acidification. As time goes on, the water in deeper and deeper wel'ls will be effected. In the Nordic countries, with sparse population areas, a great part of the water supply consists of private shallow dug wells or drilled wells in hard rocks. An overview of the water supply conditions is given in table 2, where information on public water supply, permanent residents private water supply and water supply for recreation houses is tabulated.

254 TABLE 2 Overview of water supply s t r u c t u r e i n t h e Nordic countries (22.5 M people).

Pub1 i c water

Sweden

Norway

Denmark

Finland

Iceland

Groundwater and a r t i f i c i a l groundwater ( 9 )

49

5

100

46

-

Surface water (%)

51

95

0

53

-

Permanent r e s i d e n t s

400

350

200

500

-

Recreation

650

250

30-80

250

-

Number o f people x 106 population 8.3

4.1

5.1

4.8

0.23

Permanent r e s i d e n t s

1.1

0.8

0.5

1.3

Recreation

2.0

1 .o

0

1 .o

P r i v a t e groundwater we1 1s thousands o f homes

-

17 % o f t h e t o t a l Nordic population have t h e i r own p r i v a t e wells. I f r e c r e a t i o n houses a r e included, there a r e 2.6 x 106 p r i v a t e wells a l l together. EFFECTS ON DRINKING WATER DURING DIFFERENT STAGES OF THE ACIDIFICATION PROCESS Water with pH

<

7

1. When t h e t o t a l a c i d load exceeds the base production in the ground, t h e

base s a t u r a t i o n w i l l s t e a d i l y decrease. In this phase no long-term changes i n pH will occur but changes will be seen in a l k a l i n i t y , hardness and eventually i n sulphate and n i t r a t e concentration, 6.5 and HC03 < 60 mg/l and i f the s u l f a t e content becomes I f pH

<

higher than t h e a l k a l i n i t y , this w i l l r e s u l t i n higher p i t t i n g corrosion i n primarily copper pipes. 2. When pH reaches pH < 6 the copper content w i l l reach 2-15 mg/l C u i n t a p water w i t h copper pipes a f t e r some 10 hours of contact time.

255

3. When pH 5 5.0-5.5 the aluminium content will rise to 0.2-2 mg/l Al. No systematic surveys on heavy metals in acid groundwater are carried out so far in Sweden.

Water with pH

>7

Water from carboniferous aquifers shows increasing alkalinity, hardness, sulfate and in some cases nitrate contents. DOCUMENTED INFLUENCES ON GROUNDWATER IN SWEDEN BY ATMOSPHERIC ACID DEPOSITION Changes of alkalinity and sulfate contents in well water with pH below 7 has been documented from well surveys, two of which are presented in figures 4 and 5. The implications experienced have been increased pit corrosion on water installations.

TOT*L HARDNL5S

mq', m g l

1.5-'30

30

60

90

0.5

1.h

I .5

m#l

c

ALKALINITY

mew,

Fig.4. Regression lines for hardness alkalinity in dug wells, S Sweden. (ref.6)

Fig. 5. Changes in alkalinity in 2000 dug wells in S Sweden, (ref.7)

Time series from the Swedish groundwater monitoring network, established in 1968, have not given as pronounced indications of influence o f acidification as have these two well surveys. This may be explained by the fact, that two different groundwater regimes are being studied. Well surveys represent integrated water with different transit times, times which have often been reduced by pumping. Piezometers represent water within a certain region and with a specific transit time.

256 The impact of a c i d i f i c a t i o n on groundwater w i t h pH

>

7 i n carbonate rocks,

as documented from south Sweden i n time s e r i e s s i n c e t h e 1950s, has been:inc r e a s i n g c o n t e n t s o f a l k a l i n i t y , hardness, s u l f a t e and n i t r a t e .

No s t u d i e s

concerning e f f e c t s on f o r example c o r r o s i o n , has so f a r been undertaken f o r these waters where pH

>

7.

Corrosion on concrete c a s i n g i n w e l l s has r e s u l t e d i n leakage o f s u r f a c e water i n t o t h e w e l l s w i t h contamination of o r g a n i c and m i c r o b i o l o g i c a l compounds o f t h e d r i n k i n g water. S i m i l a r changes i n w e l l water q u a l i t y caused by a c i d r a i n has been documented i n surveys o f p r i v a t e , s h a l l o w supplies.

dug w e l l s and municipal groundwater

The a l k a l i n i t y versus hardness diagram does n o t i n v o l v e e f f e c t s o f

f e r t i l i s a t i o n o r changes i n l a n d use.

The m a t e r i a l on 2.000 dug w e l l s from

Western Sweden i n d i c a t e s decreasing a l k a l i n i t y .

Numerous w e l l s on t h e Swedish

West coast, b o t h dug w e l l s and w e l l s d r i l l e d i n hard rocks, have l o s t a l k a l i n i t y and have pH's below 5.0. D r i l l e d w e l l s i n hard rocks w i t h shallow o r no overburden, a r e more i n f l u e n c e d by a c i d i f i c a t i o n , than w e l l s w i t h a t h i c k e r cover o f f o r example g l a c i a l t i l l s o i l s .

A s t a t i s t i c a l a n a l y s i s o f data from 1960, 1962, 1968 and 1980 from VAV - The

Swedish Water and Waste Water Horks A s s o c i a t i o n - from approximately

150 p u b l i c s u r f a c e and groundwater s u p p l i e s showed s t r o n g evidence o f a c i d i f i cation.

S i g n i f i c a n t changes o f t h e a l k a l i n i t y t o hardness r a t i o had occurred

between 1960 and 1980 f o r b o t h types o f water supplies.

No s t a t i s t i c a l change

No c l a s s i f i c a t i o n o f geology

i n pH was r e v e a l e d f o r t h e m a t e r i a l as a whole.

a c c o r d i n g t o base p r o d u c t i o n was performed. ( r e f . 4 ) The main consequences o f a c i d i f i c a t i o n a r e t h a t w e l l waters have become more c o r r o s i v e t o metal water pipes, have increased copper contents i n t a p water and increased aluminium contents i n groundwater.

More comprehensive

s t u d i e s on t h e presence o f heavy metals i n groundwater are l a c k i n g i n Sweden. COSTS OF CORROSION OF PRIVATE WATER SUPPLY INSTALLATIONS I N SWEDEN I n o r d e r t o e s t i m a t e t h e magnitude of c o r r o s i o n on water supply i n s t a l l a t i o n s , the t o t a l c o s t f o r i n d o o r water damage insurance companies was i n v e s t i g a t e d . 1.100 M SEK.

t h a t was r e p a i d by the

The money refunded i n 1982 amounted

Out o f t h i s amount 340 M SEK was due t o c o r r o s i o n and o u t o f

t h i s about 140 M SEK was estimated t o have been caused by a c i d i f i c a t i o n . These c o s t s w i l l increase w i t h c o n t i n u i n g h i g h d e p o s i t i o n s o f acid. The mean c o s t payed f o r by the insurance companies amounted 10,000 SEK per c l i e n t . I t i s n o t known whether t h e c o s t o f c o r r o s i o n i s m a i n l y associated w i t h

p r i v a t e water s u p p l i e s . I t should be noted t h a t p u b l i c water s u p p l i e s mainly have a l k a l i z i n g treatment o f t h e d r i n k i n g water.

I f t h i s i s t h e case 140 M SEK

257 should be assigned to 1.1 M people or about 0.4 M private homes. The costbenefit ratio for filter-installations will then be 1.0:1.7-1.0 not including costs associated with water damage on sanatory goods, laundry and increased content of metals, mainly copper in tap water. (ref.9) A NATIONAL SURVEY AND GOVERNMENT FUNDS TO COUNTERACT ACIDIFIED PRIVATE WELLS The National Swedish Environment Protection Board has requested the municipalities to perform voluntary surveying of 100-200 wells with the purpose of characterizing and quantifying the problem of acid, corrosive well water. 70 municipalities have undertaken such surveys. In December 1985 the Swedish government allocated funds to assist private wellowners with very corrosive well water and/or with copper contents in tap water over night exceeding 3 mg/l Cu. The criteria used to qua1 ify for government funds for water treatment installations are apart from the copper content being > 3 mg/l Cu, that pH < 6.5, HC03 < 60 mg/l and the sulfate content being higher than the alkalinity. All these three conditions must be fujfilled together. 70 municipalities out of 284 have carried out the survey in 1985 and another 40-50 surveys will be carried out in 1986. Results from about 10,000 well analyses and estimates based on information of the occurrence of acid surface water indicate that 70,000 private resident homes and 20-50,000 vacation houses have very corrosive well water. The majority of these wells being influenced by acidification. Alkalizing filters for private homes can be purchased for 4,000-15,000 SEK. The total investment for installation of alkalizing filters and/or soil liming have been estimated to 500-700 M SEK for wells for household consumption of permanent residents only. ACIDIFICATION AND DRINKING WATER IN SOME EUROPEAN COUNTRIES Norway Acid precipitation in Southern Norway has a pH = 4.3-4.5, which has caused considerable acidification of surface waters. Water drawn from surface water accounts for 95 % of all public water supplies. From the groundwater observation network there are 46 monitoring stations reporting water quality.

258

The following information is from shallow groundwater in soil aquifers in Southern Norway (ref.5):

PH

= 5.2-5.7

HC03 = 1-5 mg/l SO4

= 1-12

Cu

= 0.8-4.4 mg/l

mg/l

This water quality will be very corrosive to water installations, giving pitting corrosion and high copper content in copper pipes. The amount of wells with corrosive water is not known. Finland Total wet and dry deposition is less in Finland than in Sweden and Norway. Wet deposition of sulfate only locally exceeds 0.10-0.15 keq/ha,yr SO4. Snow, which is here the most important part for recharge of groundwater, has had a pH = 4.4-5.0 during the last 10 years. The impact of acidification on groundwater is not yet fully know. A groundwater observation network was established by the National Board o f Waters in 1975-76. Time series o f 8 years of water quality data are available. Regression analyses show a significant increase in sulfate, calcium and aluminium. No significant changes in pH have been observed. Some medium values are given below. (ref.14) pH

=

HC03

6.3

12

mg/l

SO4

=

6.1 mg/l

Ca

=

4.5 mg/l

el-conductivity = 6.0 m S/m This indicates that well water corrosive to water installations may occur. The occurrence and the number o f such wells are not known. Denmark

A survey carried out in the municipality

in West Jylland showed the following pH-distribution in 2,000 private wells (ref.1): o f Ringkjoebing

259

PH Wells %

< 5

5-6

6- 7

> 7

11

35

30

24

Water having pH 2 5 had increased contents of aluminium of 0.2-9.1 mg/l A l . In public groundwater supplies in 10-25 m deep borings pH and alkalinity had decreased between 1950-54 and 1980-86 from pH = 6.5 to pH = 5.6 and from 1.7 to 0.7 mg/l HC03. An analysis carried out of the hydrogen budget using the Schroeder model indicated, that 4 % of the total acid deposition could be allocated to acid rain and the remaining part t o agriculture. Only 30 % of required lime dosage of 1,300 kg/ha,yr was being applied. In Holland similarly 9-17 % of the acid load is considered being due to atmospheric deposition, farming being responsible for the remaining part causing severely acidified Uutch groundwater. (ref.10) Federal Republic of Germany Investigations carried out in the forested Taunus quartzite hills show an acidification of shallow groundwater in this non-agricultural area. Total deposition of acids is here 4 keq/ha,yr. The sulfate content in groundwater has risen from 5 mg/l SO4 in the 1960-ies to 20 mg/l SO4 25 years later. pH is low but above pH = 5.6. A comparison between shallow and deep groundwater from horizontal rock tunnels for water supply (stollen) show a great difference between shallow and deep groundwater. Nitrate range from 10-30 mg/l in shallow and from 3-15 mg/l NO3 in deep groundwater. The sulfate range is 20-50 mg/l SO4 in the shallow groundwater and 2.5-25.0 mg/l SO4 in the deep groundwater. (ref .8). This indicates that groundwater supplies in forested areas with acidic or intermediate acidic rocks with low buffer capacity have become acidified from acid precipitation. This will also be the case in many other areas in Central Europe with acidic rocks.

260

CONCLUSIONS The t o t a l atmospheric load of acids exceeds the base production i n s o i l s and rocks in many parts of Europe. T h i s i s especially the case where slowly weathering rock materials a r e prevailing, i.e.granites, gneisses, quartzites, sandstones. In these geological environments the base saturation will steadily decrease and eventually approach zero. This will imply that the groundwater will become influenced by a c i d i f i c a t i o n , primarily shallow groundwater and w i t h timesdeeper groundwater. A t f i r s t private water supplies from shallow wells and l a t e r public groundwater supplies. For water w i t h pH < 6.5 and low a l k a l i n i t y p i t t i n g corrosion will increase in indoor water i n s t a l l a t i o n s , spec. primarily copper i n s t a l l a t i o n s as a consequence of decreasing a l k a l i n i t y and increasing content of sulphur. This will occur without any decrease i n pH. The second stage i s when pH s t a r t s t o decrease. For waters w i t h pH around and l e s s than pH = 6 , the copper content w i l l increase d r a s t i c a l l y in tap After contact time of 2-3 hours the copper content water from copper pipes This may cause diarrhoea t o infant children. may increase t o 3-5 mg/ For low pH, l e s s than 5 0-5.5, the metal contents i n the groundwater i t s e l f will increase. Primari y aluminium w i t h concentrations 0.1-1.0 mg/l being frequent. The knowledge and documentation of background values and the influence of a c i d i f i c a t i o n on metals i n groundwater i s presently poor. in the Nordic countries have private water 17 % of the 22 million supplies. Decreasing a l k a l i n i t y and increasing sulphate contents have resulted i n corrosion as a consequence o f atmospheric acid deposition. A national survey has revealed an investment cost o f 500-1,000 M SEK f o r countermeasures f o r 100,000 Swedish private wells with acid corrosive drinking No estimates on public health consequences have so f a r been made. water. C r i t i c a l load l i m i t s f o r acid deposition i n order t o avoid negative consequences f o r d r i n k i n g water from groundwater supplies have t o be studied for different geological s e t t i n g s a s an i n p u t t o p o l i t i c a l decisions on reduction of acid emissions.

.

26 1

REFERENCES 1 J Bddsgdrd Pedersen, Acidification of groundwater in West Jylland (in Danish), Vandteknik, No 4 (1985), 109-115. 2 W Dickson, Which are the acceptable loadings of Atmospheric Acids to sensitive Waters, Water Quality Bulletin, Vol 1 1 , Nr 1, Environment Canada (19861, 7 PP. 3 W Dickson, Air Pollution and stability of coniferous forest Ecosystems, Int Symp Octobre 1-5, 1984, Brno, Czechoslovakia, University of Agriculture, Brno, CSSR (1985), 165-174.

4 A Grimvall, C H Cole, B Allard and P SandPn, Quality Trends of Public Water Supplies in Sweden, Water Quality Bulletin, Vol 1 1 , Nr 1 , Environment Canada (1 9861, 7 pp. 5 A Henriksen, L A Kirkhusmo, Acidification of Groundwater in Norway, Nordic Hydrology, 13 (1982), 183-192. 6 G Jacks, G Knutsson, The sensitivity to Groundwater Acidification, The CoalHealth-Environment Report (in Swedish), No 49 (1982), Stockholm, pp 125. 7

S Jonasson, L-0 LSng, S Swedberg, Controlling factors for pH and alkalinity. An analysis of private wells in SW Sweden, Swedish Environment Protection Board, SNV PM 3021, 1985, pp 84. (In Swedish.)

8

M Krieter and K Haberer, Threat of Groundwater by Acid Precipitation (in German), Wasser, Band 64 (1985), 218-242.

9 E Levlin, Acidification-related corrosion in water pipes. A preliminary cost estimate, Swedish Environment Protection Board SNV PM 1978. (In Swedish.)

10 Ministry of Agriculture and Fishery, Acidification from atmospheric deposition - Soils, Pub1 VROM 83657/1 - 84, 1984, pp 76. (In Dutch.)

1I Monitor 1981 , Acidification o f soil and groundwater (in Swedish), Swedish Environment Protection Board, Meddelande No 3 - 1981, pp 175. 12 Monitor 1984, Long-range transport of air pollutants, Swedish Environment Protection Board, Meddelande No 3 - 1984, pp 134. (In Swedish.)

13 T Paces, Sources of acidification in Central Europe estimated from elemental budgets in small basins, Nature, Vol 315, No 6014, 2 May 1985, pp 31-36.

14 J Soveri (editor), Acid Groundwater in the Nordic Countries, Nordic Hydrological Programne, NHP - Report No 3 (19821, 29 pp. 15 J Soveri, Influence of Meltwater on the amount and composition of Groundwater in Quarternary Deposits in Finland, Publications of the Water Research Institute, No 63 (1985), 92 pp.

265

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

MODELS AS TOOLS FOR ABATEMENT STRATEGIES M.L.

- AIR

QUALITY MANAGEMENT APPROACH

WILLIAMS

Warren Spring Laboratory, Gunnels Wood b a d , Stevenage, Herts (England)

ABSTRACT This paper describes the uses of dispersion and reaction models with particular reference to their role in the regulatory decision making process of air quality control. The features of an AQMS are described. This is followed by a discussion on the need for a critical evaluation of the performance of models especially when used in appraising air quality control strategies. INTRODUCTION This paper is intended to set the scene for this session on the role of modelling as a tool for the development of abatement strategies and to serve as an introduction, providing a back-drop to those papers which will follow and discuss individual aspects of modelling in more depth.

This paper therefore

will discuss in broad terms the role of air pollution modelling in the overall air quality management system.

In the first instance a brief discussion of the

various reasons for undertaking air pollution modelling will be given, and we shall see that modelling as a direct component in the pollution control decision making process is only one of several uses of air quality models.

This

discussion will be followed by an outline of the concept of an air quality management system, involving some brief examples of different implementations of such a concept in various countries.

In using air pollution models it is

obviously important for the users of both the models and users of the results (who are not necessarily the same) to have an appreciation both of the scope of applicability of the model(s)

in question

-

that is to know whether or not a

model is being used in a situation for which it was designed

-

and of the

confidence which the decision makers can place in the results of the models. Both

these

topics will be

subjects, especially

the

discussed below, somewhat selectively as both

latter issue of

sensitivities inherent in models could be conferences in themselves.

the

errors, uncertainties and

(and have been)

the subject of

Examples of the use of models in various situations

will be given using examples of urban and longer distance scales and involving primary and secondary pollutants.

On a point of terminology, in this paper the term "air quality" will be used in a broad sense to include both air concentrations and depositions, both wet and dry, of gaseous or particulate pollutants.

266 THE USES OF AIR POLLUTION MODELLING Air pollution models are constructed to simulate the action of the physical and chemical processes occurring in the atmosphere on a source or sources of pollutant emissions.

This can be carried out with varying degrees of complexity

over a range of time and distance scales, but the chief reasons for performing modelling calculations are one or other (or combinations of) the following:

-

Research

to evaluate our quantitative understanding of the important

physical and chemical aspects of the problem.

These investigations generally

result in further questions and in the need for model development and here two approaches are possible. One may wish to develop a model which while simulating the major physical and chemical features of the system, is relatively simple. The reasons for this approach may be philosophical, accepting that a full description of

the chemistry

(in both gaseous and aqueous phases in the

acidification problem for example) and the physics (of cloud formation, rain and wash-out in the same example) will not be feasible; or equally important

that

the input data required to specify emissions and the atmospheric parameters on sufficiently well-resolved time and spatial scales may not be available.

The

reasons may also be practical in that sufficient computer power for a more complex model may simply not be available-

On

the other hand, a more detailed

approach may be taken whereby one attempts to include explicitly as much of the detailed physics and chemistry of the system as is practicable given the available computer power.

There is neither time nor space here to debate these

two approaches but suffice it to say in the context of a research tool, the demands on a model may be different from those required in an operational model used in an AQMS or similar. 0

As

a

supplement to monitoring and in network design

-

air quality

monitoring is an expensive task both in terms of capital and manpower and modelling can often be profitably used to estimate concentrations or depositions in areas where for economic or other reasons monitoring is impractical.

This

interface of monitoring and modelling places significant demands on model validation

-

a topic which will be discussed below.

Similarly the use of

dispersion models as an aid in the rational design of monitoring networks can be a very powerful method for ensuring that the maximum benefit is obtained from the outlay of the networks.

This approach has been used successfully by WSL in

the design of the UK Rural Network for SO2 and also, in conjunction with other information, in the design of the UK network for monitoring compliance with the

EC N O p Directive. 0

In assessing the impact on air quality of future emission scenarios

-

this

can take two forms, one as a single source or single development assessment for example in a form of Environmental Impact Assessment, or the other in a wider

267 national or international context where for example future forecasts of national emissions and their impact on national and transboundary air quality may be The papers following in this session will discuss this application

required.

which is (together with

the next point) often of most interest to those

concerned with the decision making process.

It is also, as will be discussed

later, an application which places considerable demands on the models and also on

their developers and

users, particularly

as one moves away

from the

relatively simple linear air quality models of the Gaussian type applied over -10 km distance scales to urban air quality problems, to the more 'detailed,

often non-linear problems involving longer time and distance scales, complex chemistry, wet and dry deposition. Identification of cost-effective control strategies

-

this is often very

closely linked with the previous point but is worth highlighting on its own

In the previous paragraph, one may wish to investigate future scenarios over which one can exercise little control.

because of the importance of the issue.

However when a choice of options is open then it behoves the decision maker to employ a rational evaluation of these options.

Numerical deterministic models

offer a rational method of assessing future air quality, and coupled with adequate information on control and abatement technology costs can provide a powerful tool in assessing control strategies.

However care must be taken in

using models in these roles so that they are not simply used as a "black box" which provides unquestioned results for a series of input scenarios. Air pollution models then can provide very valuable informtion to the decision maker when used in a rational manner and are probably at their most effective when used in an integrated way with scientific analyses of the rest of the air quality mangement process, and this will be discussed briefly in the next section. AIR QUALITY MANAGEMENT SYSTEMS The management of the factors determining air quality is a complex process and the various methods used by different countries reflect the priorities and problems of each nation.

In recent years, particularly with the increasing use

of air quality standards in Europe and elsewhere, attention has turned to the formal concept of an Air Quality Management System in which all the factors determining air quality are considered i n an integrated way.

The definition and

description of an AQMS has been the subject of a NATOICCMS study (ref. 1) so only a brief description will be given here.

A schematic outline of the

components of the system are shown in Figure 1.

It should be emphasised that

this

is

a

formal definition

-

in

practice

considerable

differences in

implementation of such a system will occur with varying degrees of formality.

268 However, regardless of the way in which assessment and control mechanisms are written into national air quality management practices, sound scientific and technical information on each stage is essential before rational decisions can be taken. Controls and standards can be applied at various stages of the system

-

for

example fuel/product standards can be applied as in the case of the lead content

of petrol and the sulphur content of gas oil, both of which are the subject of EEC Directives.

At the plant stage control/abatement technology can be applied

and it is in the link between this stage and the air quality/deposition stage at the heart of the system that the role of dispersion modelling is paramount. It may be helpful to illustrate some implementations of AQMS in different countries as examples of the different approaches which may be adopted.

The

intention here is not to give an exhaustive or definitive account of such systems and approaches but simply to illustrate some salient features in the present context.

Some national systems were described in more detail in an

earlier NATO/CCMS report (ref. 2). In the USA for example, the system is founded on the air quality standards (AQS) for the regulated pollutants, so that while emission limits can be set on plantstheseare

determined such that the AQS are not breached.

achieving this assessment is a model,

so

The means of

that here models are very much an

integral part of the process and indeed evaluation and accreditation of models for appropriate roles is seen as an important task within the AQMS. The system adopted by the Federal Republic of Germany contains provision for emission standards (for a large number of substances), and for air quality standards

on

both

long

and

short

(yearly

and

half

hourly)

timescales.

Furthermore there is the requirement that emissions should be kept as low as possible by the application of best available technology to emission, product and equipment standards.

It is also a requirement that the contribution to

ambient air concentrations from a single stack should not be higher than about

1-2% of the air quality standards. use

This requirement necessarily involves the

of models. The approach of the Netherlands offers another example, in that as well as

air quality standards, national emission ceilings for SO2 (0.5 MT a-l), NOx and

NH3 have been set, which in turn lead to the setting of emission standards for appropriate plants.

Furthermore targets for the maximum deposition of acidic

species have been set amounting to 1400 effective acid equivalents per hectare per year from SO2, 900 from NOx and 690 from NH3. The foregoing discussion has been concerned with national AQMS and their implementation.

In recent years the problem of transboundary transport of air

pollution and the acidification issue, with which this meeting is concerned, has

269 There is no difference in principle between the

become increasingly important.

management of air quality (in the wide sense) at the supra-national level as outlined in Figure 1 and at the domestic level although clearly in practice this may not always be a straightforward

process.

Nonetheless the requirement for

sound scientific and technical information on each of the stages from fuels and raw materials, through plant technologies to the resulting air quality effects is still paramount.

The role of models in this international process is

still central and fundamental in answering the important questions, firstly if one wishes to reduce or ameliorate the "effects" be they aquatic acidification, vegetation damage etc, what is the required reduction in air quality/deposition necessary to achieve this? and secondly what is the most cost-effective emission reduction

of precursor pollutants which will achieve this reduction?

In the past most

attention has been primarily

focussed

on the second

question, models being used to predict air quality from a series of emission control or fuel use change scenarios.

This for example is the objective of the

PHOXA/CEC/OECD exercise to be described in more detail in a later paper t o this meeting.

In the acid deposition context one of the most important questions

currently being investigated is the form of the relationship between emissions and depositions of acidic species, in particular the extent to which nonlinearities in the gaseous and aqueous phase processes affect the proportionality of this relationship.

Equally importantly, arguably more so, is the

question of modelling the link between changes in air quality and consequent changes in effects.

This is a difficult task as many of the mechanisms of

aquatic and soil and other substrate acidification are poorly understood. Nonetheless it is essential to have a sound understanding of the likely benefits to the affected targets before embarking on what could be costly control measures.

Advances in this area will be viewed with interest and another

subsequent paper will address this issue. So far we have discussed the roles which models can play in an AQMS and in

developing rational approaches to abatement strategies.

What we shall next

consider is a rational approach to the uses of models themselves. EVALUATION AND ASSESSMENT OF MODELS IN DEVELOPING CONTROL STRATEGIES

In this section we will discuss the criteria by which the performance of a model in operational use would be judged.

All models are approximations, some

more so than others, so that validation and sensitivity analyses are essential to ensure sound performance; more fundamentally, the model should be formulated properly in the first place.

These aspects will be discussed in the following

sections, with particular reference to the acidification/transboundary transport issue.

270 Model Formulation and Data Requirements It is a truism, but nonetheless something which can be overlooked, to state that the quality of the results of a model are determined to a large extent by the quality of

the input data, which

comprise emissions, meteorological/

physical parameters and chemical mechanism/rate constant data.

Similarly the

construction of the model in its physical and chemical mechanisms should be such that the major features of the problem in hand are treated on the appropriate time and distance scales.

For example the detailed description of small scale

turbulence in a building wake, of prime importance in a street-canyon model, can be more simply treated in an urban scale (1-10 km) model or longer range model, using a semi-empirical dilution term. Emissions data

should be available on the temporal and spatial scales

appropriate to the problem.

The calculation of annual average air quality

requires annual emissions which, although themselves subject to uncertainties which can be large, are generally readily available for the major pollutants SO2 and NOx although N02/NOx ratios are not always well defined.

Photochemical

models require emission data on individual hydrocarbon species and even in annual terms these are often only very approximately known and until the recent OECD MAP exercise, no comprehensive emission data on individual hydrocarbons have been available in Europe.

For shorter time scales, of the order of days as

required by the Norwegian/EMEP sulphur deposition model, or hours which the PHOXA/SAI model requires, some method of estimating from annual values is often required.

Daily space-heatingemissions for example can be fairly confidently

estimated using the degree-day approach and this is employed by the Norwegian/ EMEP model, while in other areas vehicle emissions can be related to traffic statistics which are often available at an hourly level in major urban areas.

It is important to quantify these short timescale variations as factors of 2-3 from the long-term average can be achieved.

Moreover it is important to specify

correctly the phasing of short term variations in emissions and meteorology for example short period traffic emissions can peak in the early morning (-8-9 am) when wind speeds and mixing heights are low, leading to concentrations many times a daily or annual average. The spatial resolution of

the model is also a major constraint.

Both

Eulerian and Lagrangian transboundary models require the specification of a grid-cell size which imposes demands on the specification of emissions and also means that certain sub-grid scale physical and chemical processes must be treated approximately.

Typical grid sizes for urban air quality models are

-1 km while the EMEP sulphur deposition model uses a grid size of -150 km.

The

photochemical SAI model has been used in the USA with a grid size of -18 km and in the PHOXA and CEC/OECD applications the grid sizes are -25-50 km. It is not

27 1 always easy to obtain spatially resolved emission inventories for all the pollutants of interest.

Such data are now generally available for SO2 and NOx,

and WSL has developed UK inventorieg at -20 km resolution for these pollutants. However as

noted

above

in

the national context, spatially

disaggregated

inventories of individual hydrocarbons are more difficult to obtain. Recently a European inventory of NH3 emissions for 1982 has been developed (ref. 3 ) on a

75 km basis and a similar inventory for the UK on a 10 km grid has been produced by ApSimon and Krause (ref. 4 ) . The requirement to use large 0 1 0 km) grid sizes in long range transport models has other important implications in that sub grid square processes must necessarily be treated or parametrized in an approximate way.

For example in

many applications, large point source emissions are assumed to be instantly mixed over the volume of the grid cell.

While this may not be a serious

approximation at large downwind distances for an inert pollutant, near field concentrations will probably be poorly predicted.

Likewise the concentration

gradients which exist in reality will not be modelled directly with what may be important consequences for chemically reactive species.

In the acid deposition

context subgrid scale effects of enhanced wet deposition can also be important. Moreover when the validation of the model is being considered it should be remembered that in most cases measurements are made at a point or in the case of an aircraft a line, and calculated values are grid-cell averages over a volume so

that comparisons are thus not direct; this is also discussed in the next

section. Validation and Sensitivity of Models

In an ideal situation of unlimited resources, a thorough validation of a model would

be

large exercise involving validation of

the input data on

emissions etc as well as a thorough comparison of modelled and measured values over a wide range of locations and a long enough time period to cover the major variations in concentrations which might be expected to occur.

In practice very

detailed exercises are often not practicable particularly on an international scale.

However good coverages (in time and space) of measured data exist so

that considerable steps can be taken towards full validation of models.

Methods

of model evaluation (and the term is used here synonymously with validation although the two can be very different) have been studied in some detail by the American Meteorological Society and EPA (refs 5 . 6 ) amount of

complexity can be generated by

although a considerable

calculating a

large number of

statistics, often at the expense of understanding a model's behaviour.

It is

often enough to plot the calculated and observed quantities simply as (x,y) points, as a time series and if appropriate, as frequency distributions and

272 pollution roses.

Model performance can often be usefully expressed as a single

parameter

which is minimised for optimum agreement between calculated (C,) (C,)

and observed

concentrations.

are shown in Figs 2 and 3 for the Norwegian/EMEP Typical plots of Cci vs C oi model calculations of SO2 in air for 1978-82 (ref. 7 ) and for calculations of wet

deposition of

sulphate (ref.

8).

From

the scatter of the plots an

indication of the level of agreement is obtainable. The problem of point measurements compared with volume averaged model results has already been noted and it is imporqant therefore to have some idea of the spatial representativity of a point measurement.

This has been addressed by

Barrie (ref. 9) who attempted to quantify the uncertainty (point measurement error plus area representativeness) in annual H+, SO,+2-

and NO3- concentrations

as a function of network spacing in the Eastern USA and these are shown in Fig. 4. Predictions of models can also be expressed in a statistical or probabilistic sense as shown in Fig. 5 where a summary is given of urban SO2 concentration results from WSL‘s model applied to urban areas in the UK.

Recently Derwent

(ref. 10) has outlined a method whereby given the frequency distributions of likely values of model input parameters, the frequency distribution of the model results can be calculated, so that results can be presented in a probabilistic manner

.

Whatever methods are chosen to quantify a model evaluation, simplistic routine calculations of a series of statistics are not by themselves sufficient, and can be misleading. essential.

An investigation of the behaviour of the sub-models is

For example does the meteorological sub-model predict or use

parameters (boundary layer height, wind fields, cloud cover or radiation fluxes, wind speeds etc) which are realistic? Modelling conservative or slowly reacting species can assist in this evaluation, and certainly the sensitivity of the model output to realistic uncertainties in the input values of these parameters

In the use of photochemical models to evaluate control strategies for oxidant concentrations, the performance of the chemical sub-model is of major importance (although the specification of the physical parameters can play an important role in determining oxidant concentrations). Care must be should be investigated.

taken in such cases in asking the right questions of models

-

in the oxidant

example it is important to be clear on where, in relation to major precursor

273 emissions, one wishes

to minimise

oxidant concentrations since a control

strategy optimal for the near field will in general be different from the strategy further downwind.

Likewise at a given location, control strategies or

predictions of changes in ozone concentration following emission changes, will differ from one chemical scheme to another.

Full validation of models in these

applications is often not possible, but some recent work by Dennis (ref. 11) using three versions of the Carbon Bond Mechanism in the SAI model showed the need for a systematic investigation of the sensitivity of control strategies to different chemical schemes and also the need to model a range of ozone episodes, for while the three schemes on average predicted similar ozone changes from 1976 to 1979 in Denver (7.6%

-

lO.O%),bn some days the spread was larger,(2.4%-16.8%)

in the worst case. It is clear then that in order to assess the performance of models in a regulatory application, it is essential to evaluate the performance of the model in situations similar to that in which it is to be applied.

For example while

it may be valuable to evaluate predictions of the variation of ozone concentration under different meteorological conditions with a fixed emission inventory, this may not

necessarily offer relevant information on the ability of the

model to predict the effect of emission changes on ozone concentrations. There is a need for greater emphasis to be placed on model evaluation in a regulatory

context if rational decisions are to be taken.

This has been highlighted by

some recent work of Walker (ref. 12) which suggests that despite stringent emission controls in California and Texas, there may have been no significant changes in ambient ozone concentratons i n these areas. SUMMARY

We have seen that air pollution models can play a central role in an AQMS and can be

powerful tools in the development of

abatement strategies.

rational and

cost-effective

Indeed models represent the only quantitative prognostic

approach for the decision maker.

However models must be used in a critical way,

ensuring that they are properly formulated for the task in question and moreover that their accuracy and sensitivity are properly investigated over the range and variation in input conditions (be they meteorological or emission controls) appropriate to the regulatory questions. part of practitioners

With wide open critical eyes on the

decision-makers,models can be a very powerful part of

an AQMS. ACKNOWLEDGEMENT The UK work referred to in this paper was carried out as part of a research programme funded by the UK Department of the Environment.

A l l views expressed

274 are

those

of

the

a u t h o r , not

necessarily

those

of

the

Department

of

the

Environment. REFERENCES

Air Q u a l i t y Management Systems, A Report by NATO/CCMS P i l o t Study on Air P o l l u t i o n Assessment Methodology and Madelling, No. 7 1 , NATO/CCMS, 1979. Air P o l l u t i o n P i l o t Study Assessment Methodology and Modelling, 1st Follow-up Report, NATOICCMS, 1980. E. Buisman, J.F.M. Maas and W.A.H. Asman, Ammonia Emission i n Europe, S t a t e U n i v e r s i t y of U t r e c h t , IMOU Report No. R-85-2, 1985. H. ApSimon and M. Krause, I m p e r i a l College (UK) Report t o be published. D.G. Fox, Bull. h e r . Met. SOC., 6 2 (1981) 599. Environmental P r o t e c t i o n Agency, I n t e r i m Procedures f o r E v a l u a t i n g Air Q u a l i t y Models, Research T r i a n g l e Park, N.C., 1981. J. Lehmhaus, J. S a l t b o n e s and A. E l i a s s e n , Deposition P a t t e r n s and Transport S e c t o r Analyses €or a four-year period, Norwegian Meteorologial I n s t i t u t e , Oslo, 1985. D.A. P e r r i n , Modelling t h e Transport and Removal of Sulphur Dioxide Emissions i n t h e UK, Warren S p r i n g Laboratory, Report No. LR 560 (AP)M, 1986. L.A. Barrie, in Proc. Symp. on Monitoring and Assessment of Airborne P o l l u t a n t s w i t h S p e c i a l Emphasis on Long-Range T r a n s p o r t and Deposition of A c i d i c Materials, NRC of Canada, Ottawa, 1982, p~. p 383-411. 1 0 R.C. D e m e n t , t o be published. 11 R.L. Dennis and M.W. Downton, Atmos. Env., 18 (1984), 2055-2069. 12 H.M. Walker, J.A.P.C.A., 35 (1985) 903-912.

275

I

PLANT

.....................

PRODUCT STANDARD

I....................

EMISSION STANDARD

TRANSPORT CHEMISTRY

AIR QUALITY

................AIR QUALITY STANDARD

DEPOSlTlON

FIG, 1

27 6

25

L

24 -

23

-

E M E P - 5 YEARS D A T A : 1 9 7 8 FIG, 2

- 1982,

502 - 5

A I R CONC.

277

2.5

2.8

8.5

4f t a 1c u 1 a teci

F i g .3

Calculated (including background o f

2 0 P e q 1 - ' 1 vs Observed Wet Deposited Non - M a r i n e S u l o h a t e . 1983. aS m - 2

278

0

200

100

STATION SEPARATION , k m THE TOTAL UNCERTAINTY ( P O I N T MEASUREMENT PLUS ~

~~

~~~

AREA REPRESENTATIVENESS 1 IN ANNUAL HYDROGEN ION, SULPHATE AND NITRATE CONCENTRATION MEASUREMENTS IN THE EASTERN UNITED STATES AS A FUNCTION OF NETWORK SPACING (BARRIE, 1983 1

FIG,4

279

.x

__O_

/

CLASGOW S O 2 197718 SMOKE 197718 LONDON S O 2 197516 FORTH VALLEY S O 2 197516 FORTH VALLEY SMOKE 1975/6

--e-C L A S G O W

+

-X-

- - x--

0

1

I

I

I

1

0

1

I

ERROR

PLOTS OF PERCENTAGE OF RECEPTOR

POINTS

PERCENTAGES OF OBSERVED CWCENTRATIWS

FOR ANNUAL AVERAGE

FIG. 5

S&

1

100

50 O/a

WITHIN

1

(N = 201 IN = 171 (N = 171 (N=29) ( N = 26 1

CONCENTRATION8

281

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

TRAJECTORY MODELS OF THE LONG-RANGE A.J.Pressman,

A I R POLLUTANT TRANSMISSION

11.V.Galperin and J.E.Mikhailova

M e t e o r o l o g i c a l S y n t h e s i z i n g Centre-East,

While m o d e l l i n g t h e long-range

ENEP (USSR)

and transboundary a i r p o l l u t a n t t r a n s m i s s i o n

i t is u s u a l l y necessary t o i d e n t i f y sources r e s p o n s i b l e f o r d e p o s i t i o n a t a

g i v e n area. The problem s o l u t i o n b e i n g f o r m u l a t e d i n s u c h way can be e a s i l y made by s i m u l a t i o n of t h e h i s t o r y of p o l l u t a n t plumes i n t h e v a r i a b l e wind fields. F i r s t l e t u s c o n s i d e r p o i n t s o u r c e (Fig.

I ) a t c o n s t a n t wind. For s i m p l i -

c i t y t h e wind d i r e c t i o n i s assumed t o be c o i n c i d e n t w i t h p o s i t i v e d i r e c t i o n of

x axis. L e t u s keep t r a c k of a s i n g l e p o l l u t a n t puff e m i t t e d by a s o u r c e d u r i n g i n f i n i t e l y s h o r t t i m e i n t e r v a l a t t = 0. Using a known s o l l u t i o n from t h e s e m i empirical t u r b u l e n t d i f f u s i o n theory: t h e c o n c e n t r a t i o n a t t h e l o c a t i o n with co-ordinates

x = r , y = R a t z h e i g h t is o b t a i n e d from

5 ( r , R, where t = t i m e ,

z,

u

-1 (r-vt)* t ) = ( Z I T U ~ U ~exp ) [- 2 0 7-

T L’ I

\Y

(2,

t)

(1)

= p o l l u t a n t d i s n e r s i o n a l o n g t h e plume, UQ = d i s p e r s i o n i n t h e

t r a n s v e r s e d i r e c t i o n , V = wind s p e e d , and f u n c t i o n

Y

(z,t)

describes v e r t i c a l

d i s t r i b u t i o n of p o l l u t a n t depending on t i m e and c o n d i t i o n s of a b s o r b t i o n a t t h e earth

surface.

Other p r o c e s s e s of p o l l u t a n t removal from t h e a i r ( e . g . m a t i o n and wash-out)

chemical t r a n s f o r -

do n o t impact on t h e s p a t i a l d i s t r i b u t i o n s i n c e a s t o f i r s t

a p p r o x i m a t i o n t h e y may b e c o n s i d e r e d t o be v o l u m e t r i c a l e f f e c t s . T h e r e f o r e i t i s p o s s i b l e t o s t u d y eq. ( 1 ) w i t h o u t f a c t o r s d e s c r i b i n g t h e s e p r o c e s s e s . It is shown i n 12

I

t h a t a s u f f i c i e n t l y large-scale pollutant d i s t r i b u t i o n

( j u s t i n case of long-range be i g n o r e d , i . e . 1121:

U

+

t r a n s m i s s i o n ) t h e d i f f u s i o n i n wind d i r e c t i o n may

0 . Due t o known c h a r a c t e r i s t i c s w e have D i r a c & f u n c t i o n

282 Putting ( 2 ) into ( 1 ) we obtain

Formula ( 3 ) characterizes the concentration distributions along "infinitely thin" puff's in x

=

?.!

and z in

r direction. Fig. 1 (curve I ) shows horizontal

pollutant distribution in such a puff at distance r from the source, and Fig. 2

-

the shape of Y ( z ) function characterizing the vertical pollutant distribution. Note that the source is continuous and assuming source emission to be

constant and equal to Q state (t c

($,

-t

m).

it is possible to determine the concentration at fixed

Due to properties of &function m

I.,

z) =

I Q,

? (r, R, z , t) dt = Qs(fiVoe)-'exp(-

0

The transformation can be described in the form (Fig. I):if

-)

R2

20;

y(z,

5)

(4)

the source is

continuous then an infinitely great number of puff's that do not exchange material (or step

=

0) are located along x = r. Each puff is depleted at every time

and pollution distribution is changed within. At the same time the puff

is transported in V direction (and therefore in r) leaving the place for the next puff. However, due to stationary conditions a new puff at any point x = r will have the same features as previous one. Thus the pollutant concentration depends on Q

S'

,:,V

R and

z

and it doesn't depend on time t.

The role of t (absolute time) is transmitted to another parameter of the same dimension as t that is age of

a

given puff: T=

r ij

(5)

In view of (5) from ( 4 ) it follows that the pollution flux through the plane orthogonal to x and crossing it a point x

=

r is

characterizes the pollutant fraction remaining in the atmosphere T-time after emission. In other words function Cr(T)

is a function of pollutant removal by

dry deposition. Integrating the expression for Y ( z , T )

181 for weightless pollu-

where V = dry deposition velocity, depending on the pollutant type, KZ d cal turbulent diffusion coefficient, h = source height.

=

verti-

283 Introduction of parameter

T

allows for volumetric processes of removal,

chemical transformation and wash-out. On the assumption that these processes can be described by usual linear differential equations of the first order we obtain as wash-out function:

C,(T)

=

exp (-A

J

a

(9)

T)

where precipitation intensity J (x,y,t) depends on co-ordinates x,y and real time t, and parameters A and a depend on pollutant type and the function for chemical transformation:

5T ( T ) where

T

=

=

exp(-hTT)

(10)

2-

coefficient of chemical transformation of SO2 to SO4

. Here and

further all the values are concerned with oxidized sulphur independent of the 2-

2-

compound (SO2 or SO4 ) . Designating by indices 1 and 2 values of SO2 and SO4 we can write full functions of removal for SO

5,

(T)

and conservative pollutant C2

-

(T)

=

Cld(T)

2

ClW(T) C T ( T )

( 1 1)

sulphates =

c2d(T)

52w(T)

I n view of ( 1 1 ) and ( 1 2 ) for SO2 and sulphate fluxes we have

The above relationships from the basis of an analytical approach of model development based on the simulation of plume history in a variable wind field. The fact that pollutant amount in to use the above considerations

a

puff is utterly determined by its age allows when wind speed is varied in direction

and module (Fig. 3 ) . One should, however, adequately consider diffusion in

R direction. Let u s consider the process of plume generation and transport on the whole. Let at t moment the plume projection on x,y plane be at position 1 (Fig. 3 ) . We assume that the wind filed {V} is stationary within At time interval. The puff generated by t will be shifted to position 2 for AT time. In this time period a new puff is generated. At any point (ar = 0) diffusion in the plume will be taken as orthogonal to its axis. The plume "isnot aware" that it is curvilinear and locally it behaves as if it were rectilinear and tangent to its axis. On the basis of numerous experimentel data for Gaussian distributionldirection (see ( 4 ) ) we assume

284

where r = f u l l plume a x i s l e n g t h . The G a u s s i a n d i s t r i b u t i o n i s approximated a s uniform a t f i n a l i n t e r v a l

+ R, -

thus

]&I= where 19.1 = plume h a l f - w i d t h . assumed t h a t a t a

20 R

(16)

Thus w h i l e c o n s t r u c t i n g t h e plume i t c a n b e

f i r s t approximation h o r i z o n t a l d i f f u s i o n is proportional

t o t h e plume l e n g t h r and i s d e t e r m i n e d by e x p r e s s i o n s (15) and (16) ( l i n e 2 i n Fig.

I).

Now we s h o u l d c h o o s e v a l u e s f o r t h e b a s i c p a r a m e t e r s of r e l a t i o n s h i p s (@-(lo).

Dry d e p o s i t i o n v e l o c i t i e s (V ) f o r s u l p h u r compounds i n MSC-E models were d t a k e n from ( 5 1 , o b t a i n e d by s t a t i s t i c a l a n a l y s i s of 191 and i n f o r m a t i o n p r o v i ded by C o - o r d i n a t i n g Chemical C e n t r e (CCC) EMEP

II11

CCC's d a t a p r o c e s s i n g shows t h a t o n the a v e r a g e o v e r Europe i n January-February i s d e c r e a s e d ( a b o u t 0.6 of mean annual v a l u e ) and i n A p r i l and Octoberd November Vd exceeds mean a n n u a l v a l u e by as much a s 1.2-1.3 t i m e s . K v a r i e s 4 2 -1 w i t h s e a s o n s . The mean v a l u e of I . lo4 h-* K Z i s d e c r e a s e d t o a b o u t 1: m h V

i n January-February

and i t i s i n c r e a s e d t o l o 5 m2 h-'

i n July-August.

F o r p o l l u t a n t s w i t h l o n g l i f e t i m e ( s u l p h a t e s , i n p a r t i c u l a r ) f u n c t i o n (8) w i t h l i m i t e d T a v o i d i n g a p p r e c i a b l e l o w e r i n g of t h e a c c u r a c y c a n b e approximated

by dependence 52d(T)

=

rxp

(-A

2d'

)

(17)

2 -1 f o r s u l p h a t e s . Such a n a p p r o x i m a t i o n d o e s n ' t = 1TV2d/Kz 2 0.01 h 2d l e a d t o g r e a t e r r o r s w i t h T > l / X d I- 100 h. P o l l u t i o n t r a n s m i s s i o n o v e r Europe

where

i s o c c u r i n g 100-120 h o u r s ( n e a r l y e q u a l t o s u l p h a t e l i f e t i m e ) . Approximation

( 1 7 ) a l l o w s u s t o s i m p l i f y c a l c u l a t i o n s of s u l p h a t e d r y d e p o s i t i o n s i n c e i t f o l l o w s from ( 1 7 ) t h a t t h e f r a c t i o n of s u l p h a t e s r e s u l t e d from d r y d e p o s i t i o n does n o t depend on T a t s h o r t time i n t e r v a l A t and i t s e q u a l t o A 2dAt' F o r wash-out ( s e e ( 9 ) ) a t t h e f i r s t a p p r o x i m a t i o n N = 1 may be assumed t h e n i\ = 0.4 mm-l f o r one-layer

model and s u l p h u r compounds. T h i s v a l u e w a s

o b t a i n e d t h r o u g h r e g r e s s i o n a n a l y s i s of d a t a on SO2 and s u l p h a t e wash-out P r e c i p i t a t i o n d a t a from t h e m e t e o r o l o g i c a l network (WElO) i s PISC-E.

1111.

processed i n

A l l the meteorological s t a t i o n s t h a t provide information f o r t h e period

i n q u e s t i o n a r e s c a t t e d i n g r i d s q u a r e s and mean v a l u e f o r p o l l u t a n t f r a c t i o n a f t e r wash-out

remaining i n t h e a i r i s d e t e r m i n e d f o r e a c h s q u a r e by ( 9 )

285

M

-

CW

where M

=

=

1 C

exp(-AJAt)

i=l

number of stations in a given square. Correspondingly washed out

pollutant fraction in a square is ( I

-

yw).

Chemical transformation coefficient SO * SO-:

xT

A T (see

2

to be dependent on season 151 [ % h-l]

=

1.7

-

(10)) is assumed

(n-1)/61

COS[T

where n = number of a month in the year. For the simulation of transport information a real wind field is used. Synoptic wind and geopotential information provided by meteorological network stations is processed before its application in calculations 1101. Data of upper air measurements (not forecast) not only increase the calculation accuracy but allow us to take into account the orographic effect on transmission of pollutants. Now let us consider discrete-analytical simulation models of a trajectory type for long-range and transboundary transport of sulphur comounds based on the approach set forth above 16,7 1 . MSC-E uses models of several types aimed at the solution of two problems:

(a) calculation of pollutant fluxes across a given border with identification of sources contributing to fluxes crossing a given border segment; (b) calculation of concentration and deposition fields on the scale of a

continent and

determination of the contribution of a source to deposition at a given area. Calculation of "emitter-receiver matrices" is a particular case of the latter problem. The EMEP territory is covered by a grid (gridsize 150 x 150 km). Each grid square is considered to be an elementary pollutant s o u r c e and/or an elementary pollutant receiver. For modelling purposes it is necessary to have integral emission values for such squares. To calculate fluxes across assumed borders in the model, the pollutant

plume axis is constructed on the basis of wind data. In every time interval At at the centre of square-emitter with co-ordinates x

yo control point portion

0'

is generated transporting to the location with co-ordinates: x where u

= xo

+ uo at

;

YI

=

yo

+

v

At

(19)

and vo are wind components at the source. Each puff that leaves the

source has as its position

xn+ 1 =

*n

+ u

n

at

;

Yn+

yn

+ v

At

286 in accordance with u

and v in points xn, y , . At the sane time the number of n each puff is increased by 1. By consecutive connection of puff centres beginning n

with the source the broken line represents the plume axis at time t. In order to limit the plume length (at t

n * -)

+

it is assumed in the model that at

n > N, where N is a quantity assumed in advance, the plume is depleted and the

track of its continuation is not kept. In view of the fact that meteorological information field is changed in a discrete way every 6 hours, time step At and N

= 16

(maximum T

=

=

6

96 h) are assumed.

Horizontal plume expansion at a certain point is determined by relationships (15) and (16). In view of horizontal expansion each plume segment is transformed into a trapezium-like segment with Ar

height equal to plume axis

segment at which the segment is constructed and with bases 2Rn-1 and 2Rn

=

=

0.4 rnv1

0.4 rn with Arn = rn-l. It is assumed that pollutant is uniformly 2 - rn-~). n

distributed with segment area equal to 0.2 (r2

For each plume segment area we calculate acoording to (8), (10) and (18) the pollutant fraction remaining in the atmosphere after dry and wet deposition and chemical transformation. The calculation results can be used in two ways. First there is information on the pollutant flux crossing border contours. Note that the plume can cross the border more than once and the model is able to fix both direct and returned fluxes. Second the described scheme was successfully used for deposition and concentration calculations 17 1.

Segments at disconti-

nuity points should be reconstructed in a proper way. That is the angle formed by plume axis segments is divided by the bisector. Correspondingly plume segment area's are increased on the convex side and decreased on the concave one. In the model presented, surface concentrations are calculated by formulea resulting from ( 6 ) and (17) =

clg

where s

=

W =

(0,T) -At

(T ) 'i'

(20)

sCld(T)

area under plume segment. Dry (D) and wet (W) deposition are deter-

mined from the relationships D

where j

Q,,

=;

=

1

C V g d Qc(T)

(1

-

1

j

(23)

.) At

WJ

number of squares with centres covered by segment, At

Sulphate formation at each step At is simulated by

=

time step.

287 The approach of model development for deposition and concentration calculations can be improved. Using the segment plume construction, the consideration of asymmetry resulting from non-uniform wash-out of pollutant from segment area makes the calculation very difficult. Here the calculation is simplified but there is a possibility to make more accurate consideration of wash-out in the model based on the dynamics of individual puff's with finite area. Contrary to 141 in the last version of MSC-E model initial puff's have a 2

square shape corresponding to an emitter of 150 x 150 km

. Every hour each

emitter generates a puff with a pollutant amount equal to that of hourly emission. This puff is transported and expanded conforming with data on real wind field independent of other puff transmission from this or any other source. Designate the puff centre at tn time to be co-ordinates x

and their linear

n' Yn dimensions along Cartesian axes Xn and Yn. By analogy with (151,

it is assumed that

xn+l

= x

Yn+l

=

'n+ 1 Here

n

and

n

( 1 6 ) and ( 1 9 )

+

n

(25)

'

n'

-

Yn

n '.

+

Xn +

=

U

0.4 ;n

Yn+l = Yn + 0.4 ; (28) are the mean weighted vector components of wind speed or the

transmission velocity, the derivation of irhich isdescribed below. When the puff is in xn, yn and determined by its Length Xn, Yn, changes in its composition are estimated by ( 2 4 ) . Grid square centres covered by the puff are determined and dry and wet deposition are calculated from equations

2-

= sulphur amount (as SO and SO4 respectively) in the puff 2n 2 k = number of squares covered by puff, 5 is obtained from eq. (18). It is n wj assumed that initially the pollution is uniformly distributed within all

where mln and m

the squares which centres are covered. After dry and wet deposition over the j-th square pollutant, an amount m amount is

where k

=

j

=

m

j l

+ m

j2

is left and the total pollutant

k

number of squares covered. Hence mean wind components at t

=

nAt are

derived with allowance for contributions of individual squares

-

u

n

=

k

C u.m./m

j=l J 3

n

;

k v = C m.v./m n J J n j=l

(31)

288 These values are used for the calculations of the puff centre co-ordinates after the (n+l)-th

step from (25) and (26) and its size lengths from (27) and

(28).

Since the puff is identified with sources as well as with square-receivers "emitter-receiver matrices" are compiled simultaneously with deposition calculations. The puff's history is detected when three conditions are met: (a) puff's age

T

< 120 hours;

( b ) total puff's amount exceeds known value PD (it is usually assumed 1;

PD

=

0.5;

2 t);

(c) puff's centre is located within the calculated grid. If one of conditions (a) or (b) is violated then calculations are stopped and the remaining pollution amount is added to PVP value (background). The stored PVP value at the end of calculations for 24 hours is partially distributed within all the squares (background deposition from undecided sources) and partially this amount is considered to have left the calculated grid. Violation of conditions ( c ) leads to adding its total amount to PFB. Thus the model provides the budget of emission and deposition and pollutant

amount leaving the calculated region. In order to eliminate "failure" in the consideration of sources of low strength in case of violating condition (b), the adding to PVP and calculation ceasing is permitted only for puff's with I

, ,

1

hour. Calculations for 2 4 hours are made consecutively for all the puff's of one

plume (one source) and then for all the plumes. In case calculations have to be stopped parameters of all the puff's ithich are initial conditions for new calculations are stored. A s a result of these ronsecutive

calculations of all the plumes for

24 hours output tables of dry and wet deposition in squares and "emitter-

receiver matrices'' are provided. After diurnal deposition calculations are completed, mean diurnal surface concentration c is determined from:

and the concentration in precipitation (W cP

=

for each grid square. Index *C'

deposition through precipitation):

WE / J in these formulae shows the usage of integral

deposition in a given square, and J each square.

=

=

actual diurnal precipitation amount in

289 The p r e s e n t e d models have been t e s t e d by c a l c u l a t i o n s of f l u x e s , deposit i o n and c o n c e n t r a t i o n s and t h e r e s u l t s were compared w i t h f i e l d measurements V e r i f i c a t i o n of t h e f l u x model w a s made on t h e b a s i s of a i r c r a f t measurements

1 1 1,

The r e s u l t s a r e p r e s e n t e d i n T a b l e 1 .

For comparison o n l y 10 f l i g h t s

were a v a i l a b l e d u r i n g c a l c u l a t e d months. T h i s r e s u l t e d i n a b i a s i n s u l p h a t e data.

I n s p i t e of t h e b i a s mentioned i t i s obvious t h a t t h e agreement between c a l c u l a t e d and measured c o n c e n t r a t i o n s i n f l u x i s q u i t e s a t i s f a c t o r y .

A more r e p r e s e n t a t i v e comparison i s t h e one i n which CCC d a t a

of mean

monthly c o n c e n t r a t i o n s a r e compared w i t h d e p o s i t i o n model c a l c u l a t i o n s . To compare c a l c u l a t e d s u l p h u r c o n c e n t r a t i o n s a t t h e s u r f a c e w i t h measured o n e s , a y e a r l y p e r i o d (October 1980

-

September 1981)was

t h e t i m e of c a l c u l a t i o n , a v a i l a b l e d a t a

chosen, s i n c e a t

1 1 I f o r t h i s p e r i o d were t h e most

comprehensive o n e s . S t a t i o n s w i t h known mean monthly c o n c e n t r a t i o n s h i g h e r t h a n 3 2t h e background ( a b o u t 0.5 mg S/m f o r SO ) and w i t h few gaps i n t i m e s e r i e s 4 ( a b s e n c e of d a t a was a c c e p t e d f o r n o t more t h a n f o r 3 d a y s ) have been chosen. R e s u l t s of mean c o r r e l a t i o n c o e f f i c i e n t v a l u e s r and r e g r e s s i o n e q u a t i o n s (Y = c a l c u l a t e d , X = measured v a l u e s ) are p r e s e n t e d i n Table 2 . Note t h a t on t h e whole t h e agreement between c a l c u l a t e d and measured d a t a i s worse i n summer b e c a u s e of t h e lower s t a b i l i t y of t h e atmosphere. N e v e r t h e l e s s Tabel 2 i n d i c a t e s t h a t t h e c a l c u l a t e d r e s u l t s p r o v i d e q u i t e a c c e p t a b l e mean monthly c o n c e n t r a t i o n v a l u e s . R e l a t i v e mean r o o t - s q u a r e e r r o r of c a l c u l a t i o n s r e l a t i v e t o measured v a l u e s :

where c

and c

respectively

m

=

6

2are c a l c u l a t e d and measured c o n c e n t r a t i o n s o f SO2 and SO4

s02

=

0.16

and

=

0.23

The r a t i o s of c a l c u l a t e d and measured mean monthly v a l u e s s t a y w i t h i n t h e r a n g e of 0 . 5

-

2-

2.0 w i t h 99% p r o b a b i l i t y f o r SO2 e n 95% p r o b a b i l i t y f o r SO4

( i f we assume normal d i s t r i b u t i o n of e r r o r ) . The i n a c c u r a c y r a n g e i s 3 . 5 times

smaller f o r mean a n n u a l v a l u e s . I n view of t h e problems s e t f o r t h t h i s r e s u l t i s s t a t i s f a c t o r y enough. Model c a l c u l a t i o n s c a n g i v e

representative estimates

of t h e long-range t r a n s b o u n d a r y t r a n s m i s s i o n of a i r p o l l u t i o n .

290 REFERENCES 1

Abramovskaya S.D., et al. Resultaty samoletnykh izmerenij transgranichnykh potokov soedinenij sery. Trudy Instituta Prikladnoj Geofiziki, 1985, vyp. 62, s.64-70, Moskva, Gidrometeoizdat.

2

Karol I.L. 0 vlianii turbulentnoj diffuzii v napravlenii vetra na raspredelenie kontstentratstii, diffundirujushchej v atmosfere. - Doklady AN SSSR, 1960, tom 131, N 6, str. 1283-1286.

3

Eliassen A. The OECD Study of Long-Range Transport of Air Pollution, LongRange Transport Modelling.- Atm.Environ., 1978, v.12, N 1 , p.28-40.

4 Ellenton G., Ley B., Misra P.K. A Trajectory Puff Model of Sulfur Transport for Eastern North America.- Atm.Environ., 1985, v.19, N 5, p.727-737. 5 Galperin M.V. 0 smeshchenii otstenok soderzhaniya primesej v atmosfere obuslovlennom statisticheskimi fluktuatstiyami skorostey vyvedeniya.Meteorologiya i Gidrologiya, 1984, N 4, s.23-31. (On the shift of estimations of pollutant content in the atmosphere caused by statistical fluctuations of removal rates). 6 Izrael Yu.A., Mikhailova J.E., Pressman A.J. Model dlya operativnoy otstenki transgranichnykh potokov antropogennykh primesey. - Doklady AN SSSR, v.253, N 4, 1980, c.848-852. 7

Mikhailova J.E. Model dlya otstenki vklada krupnykh istochnikov v transgranichnoe zagryaznenie atmosfery i mestnosti soedineniyami sery v masshtabakh kontinenta.- Trudy IPG, 1982, vyp.48.

8 Monin A.S. Trudy Geofizicheskogo Instituta AN SSSR, N 33, 1956.

9 Sehmel G.A. Particle and Gas Dry Deposition: a review.- Atm.Environ., 1980, v.14, N 9.

10

Shapiro M.Ya. Objektivnij analiz polya vetra na osnovanii dannykh tentstiale i vetre.- Trudy IPG., 1982, vyp. 62, str.59-64.

11

Skielmoen T.E., Schang T., Data report October 1980 NILU EMEP/CCC, Report 6/84, Lillestrhm, 1984, 452 p.

-

o

geopo-

September 1981.-

12 Van der Pol B., Bremmer H. Operational Calculees based on the two-sided Laplace integral.- Cambridge, Univer, Press, 1950.

291 TABLE 1

Comparison of aircraft concentration measurements (mg/m3) and model calculation of fluxes

so2

Parameter Calculated Mean value

3.51

Mean root-square deviation Correlation coefficient L Regression equation (X - calculated concentrat ion, Y - measured concentration)

2*75

1

I

I

s04

Measured

Calculated

3. 85 3.1

l.O7

=

0.93X + 0.6

I

‘.43

0.74

0.83

Y

Measured

Y

=

0.98X

-

1.17

TABLE 2

N

W

N

Comparison of measured mean monthly c o n c e n t r a t i o n v a l u e s of SO

Month, y e a r

I

2

and SO w i t h c a l c u l a t e d r e s u l t s 4

I

soz-

I

M e a n

I

r

Regression equation

]Measured C a l c u l a t e d

so4 M e a n

r

Regression equation

Measured C a l c u l a t e d

October 80

3.07

2.8

0.85

Y = 0.77X + 0.44

1.14

November 80

4.53

3.9

0.79

Y = 0.79X

0.32

December 80

7.16

6.8

0.83

Y = 0.65X t 2.10

J a n u a r y 81

6.95

8.0

0.79

1.1

0.58

Y = 0.87X + 0.10

1.31

1.2

0.85

Y = 0.74X + 0.23

1.70

1.9

0.73

Y = 0.96X + 0.25

Y = 0.88X + 1.90

1.95

1.4

0.92

Y = 0.89X

t

-

0.34

February 81

6.22

7.7

0.68

Y = 1 .14X + 0.61

2.66

1.9

0.62

Y = 0.61X + 0.28

March 81

4.03

4.6

0.71

Y = 1.06X

+ 0.33

1.5

0.74

Y = 0.63X + 0.45

A p r i l 81

3.20

3.1

0.91

Y = 1 .01X

-

1.67

0.13

1.81

1.4

0.67

Y

Hay 81

2.41

2.8

0.84

Y = 1.09X

+ 0.17

1.45

1.2

0.69

Y = 0.59X + 0.34

June 81

2.00

3.5

0.72

Y = 0.89X

t

0.30

1.91

I .9

0.65

Y = 0.54X + 0.90

J u l y 81

1.65

2.3

0.67

Y = 1 . 2 1 X + 0.30

1 .48

1.3

0.53

Y = 0.68X + 0.30

August 81

1.96

2.1

0.78

Y = 0.95X + 0.24

1.44

1.7

0.68

Y = 0.61X + 0.82

September 81

2.16

2.7

0.81

Y = 0.91X t 0.73

1.85

2.6

0.88

Y = 1.13X + 0.51

Total for year

3.85

4.2

n.89

Y

1.03X + 0.23

1.70

1.6

0.83

Y = 0.94X t 0 . 0 0

=

=

0.98X

-

0.37

293

Fig. 1

‘t

Fig. 2

1

Fig. 3

4

Plume axis position 1

295

T. Schneider (Editor)/Acidification and its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

A C I D R A I N ABATEMENT STRATEGIES I N EUROPE

L . HORDIJK I n t e r n a t i o n a l I n s t i t u t e f o r Applied Systems A n a l y s i s , A 2361 Laxenburg ( A u s t r i a )

ABSTRACT The paper d e s c r i b e s b r i e f l y t h e RAINS (Regional A c i d i f i c a t i o n I n f o r m a t i o n and S i m u l a t i o n ) model and p r e s e n t s t h r e e a l t e r n a t i v e abatement s t r a t e g i e s f o r a c i d i f i c a t i o n i n Europe. These a l t e r n a t i v e s a r e : a p e r c e n t a g e r e d u c t i o n of emiss i o n s p e r c o u n t r y , r e d u c t i o n s based on i n d i c a t o r s and t a r g e t t e d e m i s s i o n reductions. INTRODUCTION

I n t e r n a t i o n a l d e l i b e r a t i o n s on r e d u c t i o n s o f e f f e c t s of a c i d d e p o s i t i o n a r e dominated by t h e f l a t - r a t e - o f - r e d u c t i o n

paradigm. T h i s i s demonstrated by t h e

p r o t o c o l s i g n e d by 21 c o u n t r i e s i n J u l y 1985 i n H e l s i n k i . A r t i c l e 2 of t h i s p r o t o c o l r e a d s : "The p a r t i e s s h a l l reduce t h e i r n a t i o n a l annual s u l p h u r emiss i o n s o r t h e i r transboundary f l u x e s by a t l e a s t 30 p e r c e n t a s soon a s p o s s i b l e and a t t h e l a t e s t by 1993 u s i n g 1980 l e v e l s a s t h e b a s i s f o r c a l c u l a t i o n of r e ductions".

Based o n 1980 e m i s s i o n s t h e t o t a l r e d u c t i o n r e s u l t i n g from t h e Euro-

pean s i g n a t o r i e s would amount t o roughly 7,500 k i l o t o n n e s s u l f u r , t h i s i s 25% of t h e e m i s s i o n s i n Europe. Although from a p o l i t i c a l p o i n t of view 30% r e d u c t i o n of SO2 e m i s s i o n s i n 2 1 c o u n t r i e s c a n be c o n s i d e r e d a s a good s t e p forward i n a b a t i n g e f f e c t s o f a c i d i f i c a t i o n , one may wonder how e f f e c t i v e and how e f f i c i e n t t h i s f l a t r a t e p o l i c y i s . I t could w e l l be t h a t a n o t h e r d i s t r i b u t i o n of 7,500 k i l o t o n n e s r e d u c t i o n of e m i s s i o n s would b e more e f f e c t i v e . The problem, however, i s t o d e f i n e e f f e c t i v e n e s s . I d e a l l y one should measure e f f e c t i v e n e s s i n terms of reduced e f f e c t s of a c i d d e p o s i t i o n o n e f f e c t c a t e g o r i e s l i k e l a k e s , s o i l s , f o r e s t s , c r o p s , mater i a l s , e t c . To t h a t end i t would b e n e c e s s a r y t o i d e n t i f y :

1. t h e dose e f f e c t r e l a t i o n s h i p s f o r t h e e f f e c t c a t e g o r i e s ; 2. t h e l o c a t i o n of t h e l a k e s , s o i l s , e t c . ,

exposed t o a c i d d e p o s i t i o n ( t h e

stock a t r i s k ) ;

3. t h e d e p o s i t i o n l e v e l s ; and 4 . t h e l i n k between d e p o s i t i o n l e v e l s and e m i s s i o n s . T h i s i n f o r m a t i o n i s o n l y p a r t i a l l y a v a i l a b l e on t h e r e g i o n a l s c a l e of Europe. N e v e r t h e l e s s p o l i c i e s t o a b a t e a c i d i f i c a t i o n a r e b e i n g developed and c a r r i e d o u t .

296 I n a n a t t e m p t t o a s s i s t t h e s e p o l i c i e s , t h e I n t e r n a t i o n a l I n s t i t u t e f o r Applied Systems A n a l y s i s (IIASA) h a s s t a r t e d a n Acid Rain P r o j e c t which developed a s e t o f l i n k e d computer models d e s c r i b i n g t h e bond

between human a c t i v i t i e s and pol-

lution effects. I n t h i s p a p e r w e w i l l b r i e f l y i n t r o d u c e t h i s model, known a s t h e RAINS (Reg i o n a l A c i d i f i c a t i o n INformation and S i m u l a t i o n ) model. D e t a i l e d d e s c r i p t i o n of RAINS c a n b e found i n Alcamo e t a l .

[ref.

L] and H o r d i j k [ r e f . 21. Furthermore

w e w i l l show some r e s u l t s of u s i n g RAINS. These r e s u l t s are meant t o b e examples of a b a t e m e n t s t r a t e g i e s and do not i n t e n d t o b e p o l i c y a d v i c e s n o r do t h e y r e f l e c t t h e view o f IIASA o r t h e N a t i o n a l Member O r g a n i z a t i o n s t h a t s u p p o r t i t . THE RAINS MODEL

F i g u r e 1 d e s c r i b e s t h e c u r r e n t s t a t u s o f t h e RAINS model. S t a r t i n g from t h e l e f t hand s i d e o f t h e f i g u r e t h e RAINS d a t a bank c o n t a i n s a number o f d i f f e r e n t e n e r g y pathways f o r Europe. These e n e r g y pathways have been d e r i v e d from p u b l i c a t i o n s by t h e Economic Commission f o r Europe [ r e f . 31 and t h e I n t e r n a t i o n a l Energy Agency [ r e f . 41 f o r e a c h of 27 l a r g e r European c o u n t r i e s . The e n e r g y use p e r c o u n t r y i s b r o k e n down i n t o 8 c a t e g o r i e s o f f u e l : h a r d c o a l , brown c o a l , d e r i v e d c o a l , l i g h t o i l , heavy o i l , d e r i v e d o i l , g a s and o t h e r s (hydro, n u c l e a r , b i o m a s s ) . The e m i s s i o n p r o d u c i n g s e c t o r s a r e c o n v e r s i o n ( r e f i n e r i e s ) , power p l a n t s , i n d u s t r y , d o m e s t i c , t r a n s p o r t and o t h e r . The e m i s s i o n s o f SO2 p e r f u e l

ACIDITY

DIRECT IMPACT

F i g . 1. C u r r e n t s t r u c t u r e o f t h e RAINS model and i t s submodels. Boxes w i t h dashed l i n e s i n d i c a t e t h a t t h e submodel h a s n o t y e t been implemented.

297 and p e r s e c t o r have been c a l c u l a t e d u s i n g s u l f u r c o n t e n t and h e a t v a l u e s o f t h e f u e l s . These numbers were c o l l e c t e d from many d i f f e r e n t d a t a s o u r c e s , b o t h i n t e r n a t i o n a l (UN, OECD) and n a t i o n a l . The number o f energy pathways i n RAINS w i l l be e x t e n d e d t o i n c l u d e a pathway i n which maximal n a t u r a l g a s u s e i s assumed and a pathway r e f l e c t i n g i n c r e a s e d e f f o r t s i n e n e r g y c o n s e r v a t i o n throughout Europe.

I n t h i s way a wide range o f p o s s i b l e e n e r g y f u t u r e s w i l l be covered by t h e RAINS d a t a bank. The model u s e r h a s many ways t o i n f l u e n c e model r u n s . T h i s b e g i n s w i t h t h e c h o i c e of a n e n e r g y pathway. S i n c e w e c o n s i d e r t h e energy f u t u r e t o b e one o f t h e l a r g e s t u n c e r t a i n t i e s , w e have l e f t t h e c h o i c e o f a p a r t i c u l a r energy f u t u r e t o t h e u s e r . The n e x t submodel of R A I N S , which c a l c u l a t e s SO2 e m i s s i o n s , c a n a l s o be i n f l u e n c e d by t h e u s e r . The menu o f R A I N S p r e s e n t s o p t i o n s f o r abatement s t r a t e g i e s : s w i t c h t o low s u l f u r f u e l s , p h y s i c a l o r chemical f u e l c l e a n i n g , des u l f u r i z a t i o n u n i t s o n power p l a n t s and combustion m o d i f i e d power p l a n t s ( e . g . f l u i d i z e d bed combustion). The u s e r c a n s e l e c t a combination o f s t r a t e g i e s f o r any c o u n t r y o r combination o f c o u n t r i e s and a l s o s e l e c t t h e y e a r o f implementat i o n and t h e e f f i c i e n c y o f t h e s t r a t e g i e s . The c o s t s o f t h e c o n t r o l p o l i c y cons t r u c t e d by t h e u s e r w i l l t h e n be p r e s e n t e d . The SO2 e m i s s i o n s a r e i n p u t t o t h e a t m o s p h e r i c t r a n s p o r t submodel. C u r r e n t l y RAINS u s e s t r a n s f e r m a t r i c e s d e r i v e d from the a t m o s p h e r i c t r a n s p o r t model develo p e d a t t h e l f e t e o r o l o g i c a l S y n t h e s i z i n g Center-West o f t h e Co-operative Programme f o r Monitoring and E v a l u a t i o n of t h e Long-Range

Transmission o f A i r P o l l u t a n t s

i n Europe (EMEP) i n O s l o . T h i s model h a s been d e s c r i b e d i n t e r a l i a i n E l i a s s e n and S a l t b o n e s [ r e f . 51 and WMO [ r e f . 6 1 . The t r a n s f e r matrices are used t o calc u l a t e d e p o s i t i o n o f s u l f u r i n g r i d s q u a r e s o f 150 x 150 km a l l o v e r Europe. A u s e r of RAINS may o b t a i n o u t p u t i n t h e form o f European maps showing s e l e c t e d i s o l i n e s o f d e p o s i t i o n o r c o l o u r e d maps showing t o t a l d e p o s i t i o n p a t t e r n s . Output o f t h e a t m o s p h e r i c t r a n s p o r t submodel i s used i n t h e f o r e s t s o i l and l a k e a c i d i t y submodels. S o i l a c i d i f i c a t i o n h a s been d e s c r i b e d as a d e c r e a s e i n t h e a c i d n e u t r a l i z i n g c a p a c i t y o f t h e s o i l [ r e f . 71. Such a d e c r e a s e may coinc i d e w i t h a d e c r e a s e i n s o i l pH. The r e a c t i o n o f t h e s o i l t o t h e incoming a c i d

stress depends o n i t s b u f f e r i n g p r o p e r t i e s . I n t h e submodel t h e s e b u f f e r i n g p r o p e r t i e s a r e d e s c r i b e d u s i n g two v a r i a b l e s , one f o r t h e g r o s s p o t e n t i a l (buff e r c a p a c i t y ) and t h e o t h e r f o r t h e r a t e o f t h e r e a c t i o n ( b u f f e r r a t e ) . Buffer i n g i s a s s u r e d t o be governed by s e v e r a l r e a c t i o n s : c a r b o n a t e , s i l i c a t e weat h e r i n g , c a t i o n exchange and aluminum b u f f e r i n g . The d a t a bank f o r t h e f o r e s t s o i l submodel c o n t a i n s t h e s p a t i a l d i s t r i b u t i o n o f 88 s o i l t y p e s i n g r i d s of lo l o n g i t u d e by 0 . 5 O l a t i t u d e . Model o u t p u t i s p r o v i d e d i n maps and graphs f o r s o i l pH, A13+ c o n c e n t r a t i o n , Ca2+/A13+

r a t i o s and b a s e s a t u r a t i o n l e v e l s . The f o r e s t

s o i l submodel h a s b e e n d e s c r i b e d i n d e t a i l i n Kauppi

al.

[ref.9

1

and Posch e t a l .

[ref.l31.

&.

[ref. 8

1,

Kxdri

298 The l a k e a c i d i f i c a t i o n submodel c o n s i s t s of s e v e r a l modules f o r meteorology, hydrology, s o i l chemistry and water q u a l i t y of l a k e s . The meteorologic module r e g u l a t e s the i n p u t flows of water and d e p o s i t i o n to the s o i l and d i r e c t l y t o t h e l a k e . The hydrologic and s o i l chemistry modules t o g e t h e r determine t h e flow of ions l e a c h i n g from t h e t e r r e s t r i a l catchment t o t h e l a k e . New e q u i l i b r i u m c o n c e n t r a t i o n s i n the l a k e water a r e then computed i n the l a k e module. Currently t h e l a k e a c i d i t y submodel has been implemented f o r Finland and Sweden. Model o u t p u t i s i n t h e form of maps of these c o u n t r i e s showing s p r i n g o r summer pH c l a s s e s of l a k e a r e a s . Documentation of t h e submodel i s provided i n Kgmgri

al.

[ r e f s . 10, 11 and 121. P r e s e n t work i n t h e RAINS model i n c l u d e s t h e f u r t h e r development of the c o s t

and d i r e c t f o r e s t impact submodels, c o n s t r u c t i o n of s e n s i t i v i t y maps f o r groundwater a c i d i f i c a t i o n , development of a NOx emissions submodel and extensive sens i t i v i t y and u n c e r t a i n t y a n a l y s i s [ r e f s . 13 and 1 4 1 . ABATEMENT OPTIONS I N EUROPE

Three Scenarios I n t h i s s e c t i o n we w i l l p r e s e n t a number of d e p o s i t i o n maps r e p r e s e n t i n g d i f f e r e n t abatement p o l i c i e s i n Europe. F i r s t w e w i l l d e s c r i b e these abatement policies. A s was s t a t e d i n t h e I n t r o d u c t i o n 21 c o u n t r i e s have pledged a 30% c u t i n SO2

emissions. O n top of t h a t , s e v e r a l c o u n t r i e s have announced h i g h e r r e d u c t i o n percentages. Table 1 column (1) p r e s e n t s a n overview o f those c o u n t r i e s and t h e i r commitments. Together we have named t h e s e commitments Current Reduction Plans. The percentages shown i n Table 1 have been derived from s e v e r a l o f f i c i a l and u n o f f i c i a l s o u r c e s . The SO2 emissions i n 1980 have been c a l c u l a t e d i n t h e R A I N S model and a r e shown i n Table 2. The same t a b l e a l s o shows the e f f e c t s of the Current Reduction Plans (Column ( 1 ) ) .

A s a next s t e p i n reducing SO2 emissions w e have looked a t t h r e e i n d i c a t o r s f o r emission i n t e n s i t y i n each country. These i n d i c a t o r s a r e : emissions per inh a b i t a n t , emissions p e r PJ, emissions p e r m2.

The i n d i c a t o r s have been calcula-

ted f o r t h e year 1995, i . e . t h e year f o r which we assume t h a t t h e Current Reduct i o n Plans have been implemented. Next t h e median values f o r t h e t h r e e indicat o r s a r e found and a d d i t i o n a l emission r e d u c t i o n s a r e c a l c u l a t e d such t h a t values of t h r e e i n d i c a t o r s a r e below t h e o r i g i n a l medians f o r a l l European c o u n t r i e s . F i n a l l y t h e average of t h e t h r e e r e d u c t i o n percentages was c a l c u l a t e d and applied t o t h e 1980 emissions of SO2 i n a l l European c o u n t r i e s . We assumed t h a t t h i s s c e n a r i o , Reductions Based on I n d i c a t o r s , w i l l be implemented such t h a t i n the year 2000 t h e c a l c u l a t e d r e d u c t i o n s have been reached. Columns (2) of Table 1 and Table 2 p r e s e n t r e d u c t i o n percentages and emission t o t a l s , r e s p e c t i v e l y .

299 TABLE 1

Percentage r e d u c t i o n

of SO2 emission

i n European c o u n t r i e s based o n 1980

emissions, f o r t h r e e s c e n a r i o s . Country Albania Austria Belgium Bulgaria Czechoslovakia Denmark Finland France Fed. Rep. of Germany German Dem. Rep. Greece Hungary Ireland Italy Luxembourg Netherlands Norway Poland Portugal Romania Spain Sweden Switzerland Turkey United Kingdom USSR (European p a r t ) Yugoslavia European average

-

50

SO 30 30 50 50 50 60 30

-

30

-

30 30 60 50

-

-

-

-

65 30

-

30

-

25

5 50 60 42

71

50

50 50 40 77 23 64 8 40 45 60 50 39 4 9 44 65 30 11 37 31

50

SO

14 50 12 4 40 50

40

5

50 17 49 50 50 2 46 3

33 8 7 47 2 50

43

30

50

44

40

(1) C u r r e n t Reduction P l a n s ( 2 ) Reductions Based o n I n d i c a t o r s (3) T a r g e t t e d Emissions Reductions

Another a l t e r n a t i v e r e d u c t i o n scheme based on t a r g e t t e d d e p o s i t i o n l e v e l s has been implemented. S i n c e no agreed set o f t a r g e t areas exists i n Europe we have t a k e n t h e t e n a r e a s where a c c o r d i n g t o o u r c a l c u l a t i o n s t h e d e p o s i t i o n i n 1980 was t h e h i g h e s t . We used a f o u r y e a r (1979-1982)

average o f EMEP t r a n s f e r

m a t r i c e s t o c a l c u l a t e t h e s e d e p o s i t i o n s . The t e n a r e a s a r e p r e s e n t e d i n Table 3 and f i g u r e 2 p r e s e n t s t h e s p a t i a l d i s t r i b u t i o n of t h e s e p o i n t s and a t h r e e d i mensional d e p o s i t i o n map f o r 1980.*) Using a n a l g o r i t h m developed and a p p l i e d by

*)The mapping h a s been developed by Maximilian Posch and Jean-Paul H e t t e l i n g h a t IIASA.

300 TABLE 2 Reduced l e v e l s of SO2 emissions i n European c o u n t r i e s f o r t h r e e s c e n a r i o s (kilotonnes S per year).

Albania Austria Belgium Bulgaria Czechoslovakia Denmark Finland France Fed. Rep. of Germany German Dem. Rep. Greece Hungary Ireland Italy Luxembourg Netherlands No m a y Po 1and Portugal

Romania Spain Sweden Switzerland Turkey United Kingdom USSR (European p a r t ) Y ugo s1a v i a Europe

39 159 432 50 8 1832 226 294 1657 1602 2415 345 813 119 1898 20 24 3 72 1741 130 757 1879 24 3 67 497 2342 8588 837

39 80 216 355 1282 113 141 829 641 1691 345 569 119 1328 14 97 36 1741 130 757 1879 85 47 497 2342 6012 837

97 36 1062 124 689 1052 85 47 442 1475 5926 586

122 80 940 126 507 1729 226 36 487 1171 4895 419

29755

22225

16879

17949

37 80 173 294 531 113 188 8 29 641 556 266 293 109 1139

11

39 80 21 6 436 916 199 282 994 80 1 1449 328 406 99 968 10

(1) C u r r e n t Reduction P l a n s ( 2 ) Reductions Based o n I n d i c a t o r s ( 3 ) T a r g e t t e d Emission Reductions

Shaw and Young [ r e f s . 15 and 1 6 1 we d e r i v e d e m i s s i o n r e d u c t i o n s such t h a t dep o s i t i o n throughout Europe w i l l be 4.0 g S/m2/yr maximum. The maximum allowed e m i s s i o n r e d u c t i o n f o r a l l European c o u n t r i e s was taken t o be 5 0 % . W i t h t h i s c o n s t r a i n t i t was i m p o s s i b l e t o r e a c h t h e t a r g e t l e v e l i n t h e Donetz and E r z g e b i r g e a r e a s . Reduction p e r c e n t a g e s and emission l e v e l s f o r t h i s s c e n a r i o ( T a r g e t t e d Emission Reductions) are shown i n columns ( 3 ) of t a b l e 1 and t a b l e 2 , respectively

.

30 1 TABLE 3 Ten areas i n Europe w i t h t h e h i g h e s t c a l c u l a t e d d e p o s i t i o n l e v e l s i n 1980.

Area Donetz Erzgeb i r g e K a towice B i l o Gora Lombardy B8rzsBny H i l l s Rhineland West Y o r k s h i r e Belgrade Moscow

*)-2

Approximate longitudellatitude

Country

39147.5 13/51 19/50 17/46 9/46 19.5148

USSR GDR/C S SR Poland Yugoslavia Italy Hungary

39/56

U n i t e d Kingdom Yugoslavia USSR

7/51 -2/53* 2 1 145

FRG

i n d i c a t e s two d e g r e e s w e s t o f Greenwich

Resulting deposition patterns The e m i s s i o n r e d u c t i o n s c a l c u l a t e d above l e a d t o d i f f e r e n t d e p o s i t i o n p a t t e r n s The RAINS model p r o v i d e s s e v e r a l o u t p u t modes t o show t h e s e d e p o s i t i o n p a t t e r n s . U n f o r t u n a t e l y i t i s n o t p o s s i b l e t o r e p r o d u c e t h e most i l l u s t r a t i v e of t h e s e m o d e s : a c O l Q u r map of Europe showing d e p o s i t i o n i n i n t e r v a l s 0-1,

1-2,

2-4,

etc.

2 g S/m / y r . Two o t h e r o p t i o n s o f RAINS have been used below.

2 F i g u r e 3 shows t h e 3 g/m / y r i s o l i n e s i n t h e y e a r 2000 f o r two s c e n a r i o s :

C u r r e n t Reduction P l a n s and R e d u c t i o n s Based o n I n d i c a t o r s . I t c a n b e concluded 2 t h a t t h e a r e a covered by d e p o s i t i o n g r e a t e r t h a n 3 g r a m e s S/m / y r i s o l i n e s w i l l he s u b s t a n t i a l l y lower i n t h e c a s e o f t h e second s c e n a r i o . In t a b l e 4 w e p r e s e n t a n overview of c o m p a r i s o n s o f t h e t h r e e s c e n a r i o s . I t c a n b e ccncluded t h a t t h e C u r r e n t Reduction P l a n s s c e n a r i o a l r e a d y r e d u c e s

peaks i n d e p o s i t i o n s u b s t a n t i a l l y . The o t h e r two s c e n a r i o s which r e q u i r e l a r g e r e m i s s i o n r e d u c t i o n s t h r o u g h o u t Europe r e d u c e t h e peaks even more. In t h e s e s c e n a r i o s d e p o s i t i o n s g r e a t e r t h a n 5 g S/m2/yr have v i r t u a l l y d i s a p p e a r e d . A t t h e same time t h e a r e a where t h e d e p o s i t i o n i s g r e a t e r t h a n 2 g S/m2/yr dec r e a s e d by a p p r o x i m a t e l y t h e same p e r c e n t a g e a s t h e e m i s s i o n r e d u c t i o n . The major d i f f e r e n c e s between t h e second and t h i r d s c e n a r i o s a r e t h e f o l l o w i n g . The r e d u c t i o n r e q u i r e d i n t h e t h i r d s c e n a r i o i s l i m i t e d t o 50% b a s e d o n 1980 f i g u r e s whereas t h e R e d u c t i o n Based on I n d i c a t o r s s c e n a r i o p o i n t s t o v e r y high r e d u c t i o n p e r c e n t a g e s i n some E a s t e r n European c o u n t r i e s . AS a r e s u l t o f t h i s , t h e deposit i o n p a t t e r n o f t h e second s c e n a r i o looks more f l a t t h a n t h e one f o r t h e t h i r d s c e n a r i o . The l a t t e r s c e n a r i o shows d e p o s i t i o n peaks i n t h e Donetz and Katowice areas o n l y . F i g u r e 4 shows t h e r e s u l t i n g d e p o s i t i o n map f o r t h e t h i r d s c e n a r i o .

302 -28.0

-19.0 -1ti.Q

-17.0 -16.8

-15.0 -1'1.0

-13.0 -12.0

1,-

7.0 !.I3

,.a

:.

0

F i g u r e 2. C a l c u l a t e d d e p o s i t i o n (gram S/m 2 /yr) i n Europe. The t e n h i g h e s t d e p o s i t i o n a r e a s a r e i n d i c a t e d o n t h e map. CONCLUSION

T h e RAINS model c a n be used t o e v a l u a t e d i f f e r e n t schemes f o r SO2 e m i s s i o n r e d u c t i o n s t h r o u g h o u t Europe. We have f o c u s e d o n d e p o s i t i o n p a t t e r n s s i n c e t h i s

i s t h e most advanced p a r t o f t h e RAINS m o d e l . Elsewhere we w i l l ores?n: e f f e c t s of t h e s c e n a r i o s p r e s e n t e d o n i n d i c a t o r s f o r f o r e s t soil

dnd

the

lake

acidification. ACKNOWLEDGEMENTS The a u t h o r i s i n d e b t e d t o the many i n d i v i d u a l s who have been working w i t h him o n t h e development o f t h e RAINS model a t I I A S A , l o Dr.R.W. Shaw from Bedford I n s t i t u t e o f Oceanography, Canada, who p r o v i d e d t h e o p t i m i z a t i o n a l g o r i t h m used i n t h i s p a p e r , t o t h e World M e t e ~ i r o l o g i c a lO r g a n i z a t i o n and the

303 TABLE 4 . A comparison of t h r e e s c e n a r i o s w i t h t h e 1980 s i t u a t i o n .

16,879

17,949

25

44

40

55

43

30

33

21

10

2

4

5 g S/mZ/yr

12

5

1

2

> 9 g S/mZ/yr

2

1

0

0

Emissions (ktonnes S/yr)

29,755

Z Reduction

22,225

-

b a s e d on 1980

Area covered by deposition > 2 g Slrn2lyr

> 4 g S/m'/yr

(1) C u r r e n t R e d u c t i o n P l a n s (2) R e d u c t i o n s Based o n I n d i c a t o r s (-')

T a r g e t t e d Emission R e d u c t i o n s

T O T Q L SULFUR SCELlRRlO*

DEPOSITION IG/M2/YRl

CURRENT REOUCTION PLANS

COMPRRED uITw REOUCTlONS BRSEO ON

INDICRTORS

2000

F i g u r e 3 . C a l c u l a t e d i s o l i n e s o f 3 g S/m 2 I y r f o r two s c e n a r i o s i n 2000.

304

20.n

19.0 1B.D

li.e

I6.O 15 0 lA.0

13.0 12.0 11.0 18.0 9.0 8.8

.

7.0 6.0

5.0

A.B 3.0 2.0 1.8 0.

F i g u r e 4 . C a l c u l a t e d d e p o s i t i o n ( g r a m e s Sfm2 / y r ) f o r Europe i n 2000, f o r t h e R e d u c t i o n Based o n I n d i c a t o r s s c e n a r i o .

UN Economic Commission f o r Europe f o r p e r m i s s i o n g i v e n t o use r e s u l t s from the

EMEP programme and to t h e Norwegian M e t e o r o l o g i c I n s t i t u t e f o r p r o v i d i n g t h e

a t m o s p h e r i c t r a n s f e r m a t r i c e s used. E r r o r s i n t h i s paper a r e t h e a u t h o r ' s responsibil i t y only. REFERENCES

1. J . Alcamo, L . H o r d i j k , J . K H m H r i , P. Kauppi, M. Posch and E . Runca, J o u r n a l of Environmental Management, 21 (1985), 47-61. 2 . L . H o r d i j k , i n A . Sydow, M . Thoma and R . Vichnevetsky ( E d s . ) , Systems Analys i s and S i m u l a t i o n 1985, V o l . 11, Akademie-Verlag B e r l i n , 1985, pp. 30-39. 3 . Economic Commission f o r Europe, An Energy E f f i c i e n t F u t u r e , B u t t e r w o r t h s , London, 1983. 4 . I n t e r n a t i o n a l Energy Agency, Coal I n f o r m a t i o n R e p o r t , OECD, P a r i s , 1985.

305 5. 6.

A. E l i a s s e n and J . S a l t b o n e s , Atmospheric Environment, 1 7 ( 1 9 8 3 ) , 1457-1473. World M e t e o r o l o g i c a l O r g a n i z a t i o n , F i n a l r e p o r t o f t h e e x p e r t m e e t i n g o n t h e

7. 8.

9. 10

I

11.

12.

13. 14. 15. 16.

a s s e s s m e n t o f t h e m e t e o r o l o g i c a l a s p e c t s o f t h e second phase o f EMEP, Techn i c a l Document WMO/TD 11, WMO, Geneva, 1984. N . van Breemen, C.T. D r i s c o l l and J. Mulder, N a t u r e , 307 ( 1 9 8 4 ) , 599-604. P. Kauppi, J . K g d r i , M. Posch, L. Kauppi and E . M a t z n e r , A c i d i f i c a t i o n o f f o r e s t s o i l s : a model f o r a n a l y z i n g i m p a c t s o f a c i d i c d e p o s i t i o n i n Europe V e r s i o n 11, IIASA C o l l a b o r a t i v e P a p e r (2-85-27, International Institute for A p p l i e d Systems A n a l y s i s , Laxenburg, 1985. J . KBmtlri, L. Kauppi, P. Kauppi, E. Matzner and M . Posch, i n C . Troyanowski ( E d . ) , A i r P o l l u t i o n and P l a n t s , VCH V e r l a g g e s e l l s c h a f t , Wrinheim, 1985, pp. 240-244. J. K t l d r i , M. Posch and L. Kauppi, i n I. J o h a n s s o n ( E d . ) , H y d r o l o g i c a l and Hydrogeochemical Mechanisms and Model Approaches t o t h e A c i d i f i c a t i o n of E c o l o g i c a l Systems, Nordic H y d r o l o g i c a l P r o g r a m e R e p o r t 1 0 , Oslo, 1985, DD. 151-170. J. Ktlmflri, M. Posch and L. Kauppi, A model f o r a n a l y z i n g l a k e w a t e r a c i d i f i c a t i o n on a l a r g e r e g i o n a l scale - P a r t 1: Model s t r u c t u r e , IIASA Coll a b o r a t i v e P a p e r CP-85-48, I n t e r n a t i o n a l I n s t i t u t e f o r A p p l i e d Systems A n a l y s i s , Laxenburg, 1985. J . K P d r i , M. Posch and J.-P. H e t t e l i n g h , A model f o r a n a l y z i n g l a k e water a c i d i f i c a t i o n o n a l a r g e r e g i o n a l scale p a r t 2: R e g i o n a l a p p l i c a t i o n , IIASA C o l l a b o r a t i v e P a p e r ( i n p r e s s ) , I n t e r n a t i o n a l I n s t i t u t e f o r A p p l i e d Systems A n a l y s i s , Laxenburg, 1986. M. Posch, L. Kauppi and 3. KPmgri, S e n s i t i v i t y a n a l y s i s of a r e g i o n a l s c a l e s o i l a c i d i f i c a t i o n model, IIASA C o l l a b o r a t i v e P a p e r CP-85-45, I n t e r n a t i o n a l I n s t i t u t e f o r A p p l i e d Systems A n a l y s i s , Laxenburg, 1985. J . Alcamo and J. B a r t n i c k i , An a p p r o a c h t o u n c e r t a i n t y o f a l o n g r a n g e s u l f u r t r a n s p o r t model, IIASA Working P a p e r W-85-88, I n t e r n a t i o n a l I n s t i t u t e f o r A p p l i e d Systems A n a l y s i s , Laxenburg, 1985. J.W.S. Young a n d R.W. Shaw, Atmospheric Environment, 20 (19861, 189-199. R.W. Shaw, Atmospheric Environment, 20 (1986), 201-206.

..

-

T. Schneider (Editor)/Acidification and its Policy Implicalions Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

307

EFFECTIVITY OF ABATEMENT STRATEGIES: PHOXA C . Ludwig'), P.J.H.

Builtjes'), W. Klug3), R. Stern4), H. Meinl 5 ) J . van Ham6), E. Weber7) presented by E. Weber Umwel tbundesamt Rerl i n , Federal Republ i c of Germany - Division Technology for Society, Apeldoorn, The Netherlands Technische Hochschule Darmstadt, Federal Republic of Germany Freie Universitat Berlin, Federal Republic of Germany Dornier System GmbH, Friedrichshafen, Federal Republic of Germany TNO - Study and Information Centre of Environmental Research, Delft, The Nether1 ands Ministry of the I n t e r i o r , Bonn, Federal Republic of Germany

* ) TNO

3, 4,

6,

7,

ABSTRACT The concept and set-up of PHOXA - Photochemical Oxidants and Acid Deposit i o n Model Application w i t h i n the Framework of Control Strategy Development i s described i n d e t a i l . The three branches acid deposition, photochemistry and data base and t h e i r mutual connections are presented. Main emphasis i s given t o the data base including the emission data base part o f the project, being essential to make further applications i n the other branches possible. To demonstrate which r e s u l t can be expected from the project i n the near future, some calculations are presented f o r a photochemical episode. INTRODUCTION The German and Dutch governments have a long history i n j o i n t studies and research on a i r pollution. In the beginning of 1983, t h e two governments decided t o s t a r t a combined project t o evaluate and quantify large scale air pollution phenomena, especially acid deposition and photochemistry, on a European scale. This proj e c t called PHOXA, Photochemical Oxidants and Acid Deposition Model Application w i t h i n the Framework of Control Strategy Development, has been s t a r t e d January 1, 1984. The aim of PHOXA is to c l a r i f y and quantify the behaviour of acid deposition and photochemistry i n Europe, because i t i s obvious from a number of studies that acid deposition and photochemistry are long range processes covering large p a r t s of Europe.

308

Because international abatement measures have t o be taken t o control acid deposition and photochemistry, international projects s h o u l d be set-up t o study acid deposition and photochemistry. In these projects as many countries as possible should co-operate and experts fran different countries should work together. Among these experts consensus should be reached about the best available knowledge and how t o apply t h i s knowledge t o arrive a t a system by which the e f f e c t i v i t y of proposed abatement strategies can be evaluated. By the end of 1984, the Commission of the European Comnunities formally joined the PHOXA project, the OECD followed i n the course of 1985, and in 1935 a l s o Scandinavian and British i n s t i t u t e s , Close relations e x i s t w i t h the EMEP project.

THE PHOXA PROGRAM

The PHOXA program i s subdivided into four strongly related branches w i t h the responsibilities indicated below: 0

0

0

Photochemf cal Oxidants: The Netherl ands/TNO Acid Deposition/Appl ication of simpler models: Federal Republic of Germany/TH Darmstadt Acid Deposition/Application of complex models: Federal Republic of Germany/FU Bet1 i n Data Bases: Federal Republic of Germany/Dornier System; The Netherl ands/TNO.

The following items are of main interest: ( a ) Model i ng area According to the long-range transport phenomena involved, a modeling area covering almost entir$y North-Western Europe has been chosen. The border1 ines of this area are: 10' longitude West, 24" longitude East, 47" 30' l a t i t u d e Morth, 60' l a t i t u d e North. The area Covers 3.129.000 km2.

As can be seen from Fig. 1, most of t h e main emisslon areas o f Western Europe a r e contalned w i t h i n the model area, which prevents the atmospheric processes occurring inside from being dominated by the fluxes across the boundaries of t h e model area.

309

For modeling purposes the area i s covered by a latitude/longitude grid w i t h a g r i d resolution of 112" longitude x 1/4" l a t i t u d e which gives 3400 grid elements each with an area o f approximately 30 x 30 km2. F i g . 1 shows also the r e l a t i v e location of the PHOXA area t o t h a t covered by the ECEKMEP project. W i t h i n a cooperation w i t h OECD the PHOXA area will be extended t o the North as shown by the dashed l i n e i n the Figure 1. Dispersion models In PHOXA several dispersion models are applied from rather simple models t o more sophisticated ones u p t o highly cmplex models. Depending on the specif i c question, the most suitable model w i l l be used. Concerning photochemical oxidants the investigation of h i g h concentration episodes i s o f major i n t e r e s t a t present whereas for acid deposition episodic as well as long-term calculations are performed. (b)

The following models are applied: Photochemical O x i d a n t s (Episode Calculations) Regional Transport Model 111 (RMT 111 Model) developped by Systems Applications Inc. USA. T h i s model contains a rather detailed chemistry module, based upon the carbon-bond concept.

A)

B) Acid Deposition B 1 ) SO2 and reaction products

Episode calculations - TDMB grid model (TH Darmstadt) - RIVM grid model (Rijksinstituut v o w Volksgezondheid en Milieuhy-

-

0

giene, Bilthoven) Transport and Deposition of Acidifylng Pollutants (TADAP) model, Environmental Research and Technology, USA. The development of t h i s highly complex grid model has been sponsored by Ontario Ministry of Envi romnent, E n v i romnent Canada and Umwel tbundesamt, Federal Republic of Germany.

Long-term calculations TDMB grid model (TH Darmstadt) EMEP model (MSC-West, Oslo).

-

310

62) NO,

and r e a c t i o n products

The process o f s e l e c t i n g t h e a p p r o p r i a t e models f o r episodic and f o r longt e n c a l c u l a t i o n s i s s t i l l under way. c ) P e r i ods s e l e c t e d f o r c a l c u l a t i o n s W i t h i n t h e present phase o f PHOXA t h e models w i l l be a p p l i e d t o t h e f o l l o w i n g time p e r i o d s which have been s e l e c t e d according t o concentration/deposit i o n measurements o u t o f t h e p e r i o d 1980 0

1983:

Photochemical o x i d a n t s 22.07. 29.05. 03.06.

0

-

-

-

-

26.07.1980

(PHOXA)

02.06.1982

(PHOXA/CEC)

06.06.1982

(PHOXA/OECD)

Acid d e p o s i t i o n Episodes:

26.02. 20.02.

-

-

01.03.1982

( s i m p l e r models)

11.03.1982

(TADAP)

Long- term: 1982. I t should be s t r e s s e d t h a t f o r model v a l i d a t i o n purposes the i n v e s t i g a t i o n

o f a l a r g e v a r i e t y o f d i f f e r e n t t i m e periods, showing d i f f e r e n t c h a r a c t e r i s t i c s , i s required. d) Data bases F o r model a p p l i c a t i o n s data bases have been e s t a b l i s h e d concerning emission, meteorology, ambient a i r concentrations/deposition and l a n d use. The emission d a t a base comprises t h e f o l l o w i n g substances: SOp, SO,-, NO2,

CO,

+ NH3,

NO,

anthropogenic VDC emissions ( s p l i t - u p i n d i f f e r e n t c a t e g o r i e s )

and VOC emissions from f o r e s t s . The data base shows a degree o f d i f f e r e n t i a t i o n i n terms o f source types which a l l o w s t o assess i n d e t a i l the c o n t r i b u t i o n o f d i f f e r e n t source types t o c o n c e n t r a t i o n and d e p o s i t i o n l e v e l s . The base year o f t h i s data base i s 1980. Special programs make i t p o s s i b l e t o c r e a t e data bases f o r o t h e r years and f o r s p e c i f i c episodes by i n c l u d i n g temperature i n f l u e n c e s and o p e r a t i n g procedures f o r major sources. A t present a d e t a i l e d comparison i s c a r r i e d o u t between t h i s PHOXA emission

data base and t h e i n v e n t o r i e s obtained by t h e OECD and emission i n f o r m a t i o n obtained by t h e Commission o f t h e European Communities.

311 The m e t e o r o l o g i c a l i n p u t r e q u i r e d depends on t h e models applied. I n p r i n c i p l e , t h e r e a r e two ways t o c r e a t e t h e meteorological input: by d e r i v i n g i t fran o b s e r v a t i o n s

by u s i n g a m e t e o r o l o g i c a l p r e d i c t i o n mode Both methods a r e a p p l i e d w i t h i n PHOXA. For t h e SAI-RTM 111 model t h e wind and m i x i n h e i g h t f i e l d s have been c r e a t e d by t h e Royal Dutch M e t e o r o l o g i c a l I n s t i t u t e , the f i e l d s o f t h e o t h e r parameters by Free U n i v e r s i t y B e r l i n . The meteorological i n p u t r e q u i r e d by t h e ERT-TADAP model f o r a c i d d e p o s i t i o n c a l c u l a t i o n s i s e n t i r e l y d e r i v e d from t h e weather p r e d i c t i o n model o f t h e German Weather Service, c a l l e d EUROPE-Modell. I n order t o d e r i v e i n i t i a l and boundary c o n d i t i o n s and f o r model v a l i d a t i o n purposes measured c o n c e n t r a t i o n and d e p o s i t i o n data a r e quired. W i t h i n t h i s data base t h e f o l l o w i n g q u a n t i t i e s f o r a number o f s u i t a b l e measuring s t a t i o n s are assembled: c o n c e n t r a t i o n o f gases:

SO2, NO, NO2, 03, PAN c o n c e n t r a t i o n o f aerosols:

SO,-,

NO,;

+

NH4

precipitation:

SO,-,

NO,;

+

+

NH4, C1-, H

,

pH.

The data have been submitted by s t a t e agencies and by the Chemical C b o r d i n a t i n g Centre o f EMEP in Oslo. Concerning model v a l i d a t i o n t h e r e i s no doubt t h a t a model which aims a t s u p p o r t i n g c o n t r o l s t r a t e g y development has t o be v a l i d a t e d . A l s o the u n c e r t a i n t i e s i n v o l v e d i n model a p p l i c a t i o n s have t o be known q u a n t i t a t i v e l y . The present procedure o f comparing c a l c u l a t e d volume

-

averaged q u a n t i t i e s

w i t h the corresponding q u a n t i t i e s d e r i v e d from p o i n t measurements can only be considered as

a f i r s t step towards a more comprehensive and systematic

Val i d a t i o n approach. E s p e c i a l l y t h e v a l i d a t i o n o f long-range t r a n s p o r t models showing a h i g h degree o f complexity r e q u i r e s t h e s o l u t i o n o f a v a r i e t y o f methodological problems. Consequently, PHOXA has s t a r t e d the development o f a Val i d a t i o n framework f o r i t s d i s p e r s i o n models.

312 Land use i n f o r m a t i o n i s r e q u i r e d 0

t o d e r i v e micro-meteorological parameters

0

t o d e r i v e d r y d e p o s i t i o n v e l o c i t i e s and

0

t o c a l c u l a t e b i o g e n i c emfssions.

The l a n d use data base f o r PHOXA c o n t a i n s t h e f o l l o w i n g c a t e g o r i e s :

01 water s u r f a c e 02 cropland, a r a b l e l a n d 03 meadows, grass1 and 04 permanent crops

05 06 07 08 09

b u i l t - u p areas deciduous f o r e s t conifers mixed f o r e s t bare s o i l

10 wetland. Per g r i d c e l l t h e p e r c e n t coverage of each o f t h e above c a t e g o r i e s i s given. From t h e i r d i s t r i b u t i o n a mean roughness l e n g t h and a mean d r y deposit i o n v e l o c i t y a r e c a l c u l a t e d per g r i d c e l l .

FIRST, PRELIMINARY, RESULTS A f t e r having e s t a b l i s h e d t h e i n p u t data bases consuming work o f r o u g h l y 2 years

-

-

which was q u i t e a time

f i r s t r e s u l t s have been obtained by

c a r r y i n g o u t c a l c u l a t i o n s f o r a five-day photochemical episode i n 1980,

22-26 J u l y . Fig. 2 and F i g . 3 g i v e two examples f o r t h e r e s u l t s obtained. F i g . 2 shows a comparison between c a l c u l a t e d and measured ozone concentrations w i t h i n the e n t i r e study area f o r a s p e c i f i c hour. It can be seen t h a t the s t r u c t u r e of the measured and t h e c a l c u l a t e d c o n c e n t r a t i o n f i e l d i s q u i t e s i m i l a r and t h a t t h e c a l c u l a t e d maximum corresDonds

-

in terms o f h e i g h t and l o c a t i o n

t h e measurements. Fig. 3 shows t h e time s e r i e s on an hour-by-hour

-

with

basis o f the c a l c u l a t e d and

t h e measured c o n c e n t r a t i o n s f o r t h e m o n i t o r i n g s t a t i o n Langenbrijgge i n t h e Federal Republic o f Germany. Again, t h e model shows s k i 1 1s.

q u i t e good p r e d i c t i v e

313 I n a d d i t i o n t o t h e demonstration o f t h e model's s k i l l t o reasonably simul a t e t h e d i s t r i b u t i o n o f ozone i n space and time, t h e f o l l o w i n g main conclusions from t h e r e s u l t s obtained u p t i l now can be drawn: 0

D u r i n g extended time p e r i o d s r a t h e r h i g h ozone concentrations may occur w i t h i n t h e study area. These concentrations may exceed 100 ppb.

0

The area a f f e c t e d by

the

h i g h c o n c e n t r a t i o n s may cover l a r g e p a r t s o f

t h e study area. T h i s i s a c l e a r - c u t i n d i c a t i o n t h a t the ozone problem i s a m u l t i - n a t i o n a l problem i n Europe w i t h corresponding p o l i c y i m p l i cations. The r e s u l t s a r e a t present subjected t o a thorough i n v e s t i g a t i o n w h i c h includes s e n s i t i v i t y a n a l y s i s . More d e f i n i t e r e s u l t s w i l l be obtained i n the near f u t u r e . T h i s a p p l i e s a l s o f o r t h e a c i d d e p o s i t i o n branch o f PHOXA.

314

F i g . 1:

PHOXA and EMEP study area

F i g . 2:

H o u r l y Averaged Predicted Mixed-Layer 03 Concentrations

With Inserted Observations For Hour Endinq I800 on 7 / 26 / 80

(ppbl W

c

cn

. -

. I4

Fig. 3:

measurements calculations

Calculated versus measured concentrations of ozone ( h o u r l y values) for Langenbrugge, Federal Republ i c o f Germany

T. Schneider (Editor)/Acidification and its Policy Implicalions Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

307

EFFECTIVITY OF ABATEMENT STRATEGIES: PHOXA C . Ludwig'), P.J.H.

Builtjes'), W. Klug3), R. Stern4), H. Meinl 5 ) J . van Ham6), E. Weber7) presented by E. Weber Umwel tbundesamt Rerl i n , Federal Republ i c of Germany - Division Technology for Society, Apeldoorn, The Netherlands Technische Hochschule Darmstadt, Federal Republic of Germany Freie Universitat Berlin, Federal Republic of Germany Dornier System GmbH, Friedrichshafen, Federal Republic of Germany TNO - Study and Information Centre of Environmental Research, Delft, The Nether1 ands Ministry of the I n t e r i o r , Bonn, Federal Republic of Germany

* ) TNO

3, 4,

6,

7,

ABSTRACT The concept and set-up of PHOXA - Photochemical Oxidants and Acid Deposit i o n Model Application w i t h i n the Framework of Control Strategy Development i s described i n d e t a i l . The three branches acid deposition, photochemistry and data base and t h e i r mutual connections are presented. Main emphasis i s given t o the data base including the emission data base part o f the project, being essential to make further applications i n the other branches possible. To demonstrate which r e s u l t can be expected from the project i n the near future, some calculations are presented f o r a photochemical episode. INTRODUCTION The German and Dutch governments have a long history i n j o i n t studies and research on a i r pollution. In the beginning of 1983, t h e two governments decided t o s t a r t a combined project t o evaluate and quantify large scale air pollution phenomena, especially acid deposition and photochemistry, on a European scale. This proj e c t called PHOXA, Photochemical Oxidants and Acid Deposition Model Application w i t h i n the Framework of Control Strategy Development, has been s t a r t e d January 1, 1984. The aim of PHOXA is to c l a r i f y and quantify the behaviour of acid deposition and photochemistry i n Europe, because i t i s obvious from a number of studies that acid deposition and photochemistry are long range processes covering large p a r t s of Europe.

308

Because international abatement measures have t o be taken t o control acid deposition and photochemistry, international projects s h o u l d be set-up t o study acid deposition and photochemistry. In these projects as many countries as possible should co-operate and experts fran different countries should work together. Among these experts consensus should be reached about the best available knowledge and how t o apply t h i s knowledge t o arrive a t a system by which the e f f e c t i v i t y of proposed abatement strategies can be evaluated. By the end of 1984, the Commission of the European Comnunities formally joined the PHOXA project, the OECD followed i n the course of 1985, and in 1935 a l s o Scandinavian and British i n s t i t u t e s , Close relations e x i s t w i t h the EMEP project.

THE PHOXA PROGRAM

The PHOXA program i s subdivided into four strongly related branches w i t h the responsibilities indicated below: 0

0

0

Photochemf cal Oxidants: The Netherl ands/TNO Acid Deposition/Appl ication of simpler models: Federal Republic of Germany/TH Darmstadt Acid Deposition/Application of complex models: Federal Republic of Germany/FU Bet1 i n Data Bases: Federal Republic of Germany/Dornier System; The Netherl ands/TNO.

The following items are of main interest: ( a ) Model i ng area According to the long-range transport phenomena involved, a modeling area covering almost entir$y North-Western Europe has been chosen. The border1 ines of this area are: 10' longitude West, 24" longitude East, 47" 30' l a t i t u d e Morth, 60' l a t i t u d e North. The area Covers 3.129.000 km2.

As can be seen from Fig. 1, most of t h e main emisslon areas o f Western Europe a r e contalned w i t h i n the model area, which prevents the atmospheric processes occurring inside from being dominated by the fluxes across the boundaries of t h e model area.

309

For modeling purposes the area i s covered by a latitude/longitude grid w i t h a g r i d resolution of 112" longitude x 1/4" l a t i t u d e which gives 3400 grid elements each with an area o f approximately 30 x 30 km2. F i g . 1 shows also the r e l a t i v e location of the PHOXA area t o t h a t covered by the ECEKMEP project. W i t h i n a cooperation w i t h OECD the PHOXA area will be extended t o the North as shown by the dashed l i n e i n the Figure 1. Dispersion models In PHOXA several dispersion models are applied from rather simple models t o more sophisticated ones u p t o highly cmplex models. Depending on the specif i c question, the most suitable model w i l l be used. Concerning photochemical oxidants the investigation of h i g h concentration episodes i s o f major i n t e r e s t a t present whereas for acid deposition episodic as well as long-term calculations are performed. (b)

The following models are applied: Photochemical O x i d a n t s (Episode Calculations) Regional Transport Model 111 (RMT 111 Model) developped by Systems Applications Inc. USA. T h i s model contains a rather detailed chemistry module, based upon the carbon-bond concept.

A)

B) Acid Deposition B 1 ) SO2 and reaction products

Episode calculations - TDMB grid model (TH Darmstadt) - RIVM grid model (Rijksinstituut v o w Volksgezondheid en Milieuhy-

-

0

giene, Bilthoven) Transport and Deposition of Acidifylng Pollutants (TADAP) model, Environmental Research and Technology, USA. The development of t h i s highly complex grid model has been sponsored by Ontario Ministry of Envi romnent, E n v i romnent Canada and Umwel tbundesamt, Federal Republic of Germany.

Long-term calculations TDMB grid model (TH Darmstadt) EMEP model (MSC-West, Oslo).

-

310

62) NO,

and r e a c t i o n products

The process o f s e l e c t i n g t h e a p p r o p r i a t e models f o r episodic and f o r longt e n c a l c u l a t i o n s i s s t i l l under way. c ) P e r i ods s e l e c t e d f o r c a l c u l a t i o n s W i t h i n t h e present phase o f PHOXA t h e models w i l l be a p p l i e d t o t h e f o l l o w i n g time p e r i o d s which have been s e l e c t e d according t o concentration/deposit i o n measurements o u t o f t h e p e r i o d 1980 0

1983:

Photochemical o x i d a n t s 22.07. 29.05. 03.06.

0

-

-

-

-

26.07.1980

(PHOXA)

02.06.1982

(PHOXA/CEC)

06.06.1982

(PHOXA/OECD)

Acid d e p o s i t i o n Episodes:

26.02. 20.02.

-

-

01.03.1982

( s i m p l e r models)

11.03.1982

(TADAP)

Long- term: 1982. I t should be s t r e s s e d t h a t f o r model v a l i d a t i o n purposes the i n v e s t i g a t i o n

o f a l a r g e v a r i e t y o f d i f f e r e n t t i m e periods, showing d i f f e r e n t c h a r a c t e r i s t i c s , i s required. d) Data bases F o r model a p p l i c a t i o n s data bases have been e s t a b l i s h e d concerning emission, meteorology, ambient a i r concentrations/deposition and l a n d use. The emission d a t a base comprises t h e f o l l o w i n g substances: SOp, SO,-, NO2,

CO,

+ NH3,

NO,

anthropogenic VDC emissions ( s p l i t - u p i n d i f f e r e n t c a t e g o r i e s )

and VOC emissions from f o r e s t s . The data base shows a degree o f d i f f e r e n t i a t i o n i n terms o f source types which a l l o w s t o assess i n d e t a i l the c o n t r i b u t i o n o f d i f f e r e n t source types t o c o n c e n t r a t i o n and d e p o s i t i o n l e v e l s . The base year o f t h i s data base i s 1980. Special programs make i t p o s s i b l e t o c r e a t e data bases f o r o t h e r years and f o r s p e c i f i c episodes by i n c l u d i n g temperature i n f l u e n c e s and o p e r a t i n g procedures f o r major sources. A t present a d e t a i l e d comparison i s c a r r i e d o u t between t h i s PHOXA emission

data base and t h e i n v e n t o r i e s obtained by t h e OECD and emission i n f o r m a t i o n obtained by t h e Commission o f t h e European Communities.

311 The m e t e o r o l o g i c a l i n p u t r e q u i r e d depends on t h e models applied. I n p r i n c i p l e , t h e r e a r e two ways t o c r e a t e t h e meteorological input: by d e r i v i n g i t fran o b s e r v a t i o n s

by u s i n g a m e t e o r o l o g i c a l p r e d i c t i o n mode Both methods a r e a p p l i e d w i t h i n PHOXA. For t h e SAI-RTM 111 model t h e wind and m i x i n h e i g h t f i e l d s have been c r e a t e d by t h e Royal Dutch M e t e o r o l o g i c a l I n s t i t u t e , the f i e l d s o f t h e o t h e r parameters by Free U n i v e r s i t y B e r l i n . The meteorological i n p u t r e q u i r e d by t h e ERT-TADAP model f o r a c i d d e p o s i t i o n c a l c u l a t i o n s i s e n t i r e l y d e r i v e d from t h e weather p r e d i c t i o n model o f t h e German Weather Service, c a l l e d EUROPE-Modell. I n order t o d e r i v e i n i t i a l and boundary c o n d i t i o n s and f o r model v a l i d a t i o n purposes measured c o n c e n t r a t i o n and d e p o s i t i o n data a r e quired. W i t h i n t h i s data base t h e f o l l o w i n g q u a n t i t i e s f o r a number o f s u i t a b l e measuring s t a t i o n s are assembled: c o n c e n t r a t i o n o f gases:

SO2, NO, NO2, 03, PAN c o n c e n t r a t i o n o f aerosols:

SO,-,

NO,;

+

NH4

precipitation:

SO,-,

NO,;

+

+

NH4, C1-, H

,

pH.

The data have been submitted by s t a t e agencies and by the Chemical C b o r d i n a t i n g Centre o f EMEP in Oslo. Concerning model v a l i d a t i o n t h e r e i s no doubt t h a t a model which aims a t s u p p o r t i n g c o n t r o l s t r a t e g y development has t o be v a l i d a t e d . A l s o the u n c e r t a i n t i e s i n v o l v e d i n model a p p l i c a t i o n s have t o be known q u a n t i t a t i v e l y . The present procedure o f comparing c a l c u l a t e d volume

-

averaged q u a n t i t i e s

w i t h the corresponding q u a n t i t i e s d e r i v e d from p o i n t measurements can only be considered as

a f i r s t step towards a more comprehensive and systematic

Val i d a t i o n approach. E s p e c i a l l y t h e v a l i d a t i o n o f long-range t r a n s p o r t models showing a h i g h degree o f complexity r e q u i r e s t h e s o l u t i o n o f a v a r i e t y o f methodological problems. Consequently, PHOXA has s t a r t e d the development o f a Val i d a t i o n framework f o r i t s d i s p e r s i o n models.

312 Land use i n f o r m a t i o n i s r e q u i r e d 0

t o d e r i v e micro-meteorological parameters

0

t o d e r i v e d r y d e p o s i t i o n v e l o c i t i e s and

0

t o c a l c u l a t e b i o g e n i c emfssions.

The l a n d use data base f o r PHOXA c o n t a i n s t h e f o l l o w i n g c a t e g o r i e s :

01 water s u r f a c e 02 cropland, a r a b l e l a n d 03 meadows, grass1 and 04 permanent crops

05 06 07 08 09

b u i l t - u p areas deciduous f o r e s t conifers mixed f o r e s t bare s o i l

10 wetland. Per g r i d c e l l t h e p e r c e n t coverage of each o f t h e above c a t e g o r i e s i s given. From t h e i r d i s t r i b u t i o n a mean roughness l e n g t h and a mean d r y deposit i o n v e l o c i t y a r e c a l c u l a t e d per g r i d c e l l .

FIRST, PRELIMINARY, RESULTS A f t e r having e s t a b l i s h e d t h e i n p u t data bases consuming work o f r o u g h l y 2 years

-

-

which was q u i t e a time

f i r s t r e s u l t s have been obtained by

c a r r y i n g o u t c a l c u l a t i o n s f o r a five-day photochemical episode i n 1980,

22-26 J u l y . Fig. 2 and F i g . 3 g i v e two examples f o r t h e r e s u l t s obtained. F i g . 2 shows a comparison between c a l c u l a t e d and measured ozone concentrations w i t h i n the e n t i r e study area f o r a s p e c i f i c hour. It can be seen t h a t the s t r u c t u r e of the measured and t h e c a l c u l a t e d c o n c e n t r a t i o n f i e l d i s q u i t e s i m i l a r and t h a t t h e c a l c u l a t e d maximum corresDonds

-

in terms o f h e i g h t and l o c a t i o n

t h e measurements. Fig. 3 shows t h e time s e r i e s on an hour-by-hour

-

with

basis o f the c a l c u l a t e d and

t h e measured c o n c e n t r a t i o n s f o r t h e m o n i t o r i n g s t a t i o n Langenbrijgge i n t h e Federal Republic o f Germany. Again, t h e model shows s k i 1 1s.

q u i t e good p r e d i c t i v e

313 I n a d d i t i o n t o t h e demonstration o f t h e model's s k i l l t o reasonably simul a t e t h e d i s t r i b u t i o n o f ozone i n space and time, t h e f o l l o w i n g main conclusions from t h e r e s u l t s obtained u p t i l now can be drawn: 0

D u r i n g extended time p e r i o d s r a t h e r h i g h ozone concentrations may occur w i t h i n t h e study area. These concentrations may exceed 100 ppb.

0

The area a f f e c t e d by

the

h i g h c o n c e n t r a t i o n s may cover l a r g e p a r t s o f

t h e study area. T h i s i s a c l e a r - c u t i n d i c a t i o n t h a t the ozone problem i s a m u l t i - n a t i o n a l problem i n Europe w i t h corresponding p o l i c y i m p l i cations. The r e s u l t s a r e a t present subjected t o a thorough i n v e s t i g a t i o n w h i c h includes s e n s i t i v i t y a n a l y s i s . More d e f i n i t e r e s u l t s w i l l be obtained i n the near f u t u r e . T h i s a p p l i e s a l s o f o r t h e a c i d d e p o s i t i o n branch o f PHOXA.

314

F i g . 1:

PHOXA and EMEP study area

F i g . 2:

H o u r l y Averaged Predicted Mixed-Layer 03 Concentrations

With Inserted Observations For Hour Endinq I800 on 7 / 26 / 80

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Fig. 3:

measurements calculations

Calculated versus measured concentrations of ozone ( h o u r l y values) for Langenbrugge, Federal Republ i c o f Germany

T. Schneider (Editor)/Acidification and its Policy Implications 0 Elsevier Science Publishers B.V., Amsterdam

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317

Printed i n T h e Netherlands

GENERAL SURVEY O F E F F E C T S

D.J.Kuenen One of t h e c h a r a c t e r i s t i c s of mankind is summarized by t h e word " C u l t u r e " .

I t i m p l i e s o u r way o f l i f e , o u r s o c i a l s t r u c t u r e , o u r h i s t o r y , t h e way we l i v e a n d f e e d o u r s e l v e s a n d o u r c o n c e p t s of t h e f u t u r e . It c o n c e r n s t h e r e l a t i o n we have w i t h e a c h o t h e r a n d w i t h t h e w o r l d a r o u n d u s . H i s t o r y , r e l i g i o n , e s t h e t i c s , e t h i c s a n d many r e l a t e d c o n c e p t s a r e commonly u s e d words a l t h o u g h t h e i r i n t e r p r e t a t i o n h a s o f t e n v a r i e d d e p e n d i n g upon t h e p e r i o d a n d t h e t y p e of c u l t u r e we l i v e i n .

It is c o m p a r a t i v e l y new t h a t t h e word e n v i r o n m e n t h a s become a h o u s e h o l d word. Our a t t i t u d e t o w a r d

o u r e n v i r o n m e n t is now a n e x p l i c i t p a r t of o u r c u l -

t u r e a n d is a n i s s u e i n o u r d a i l y l i f e a n d work. Environment i s becoming a n e v e r g r o w i n g c o n c e r n a l l o v e r t h e w o r l d . The p r o b l e m s h a v e m a i n l y o r i g i n a t e d i n t h e technologically

a d v a n c e d c o u n t r i e s , b u t are now a c o n c e r n r i g h t i n t o t h e most

remote r e g i o n s of t h e e a r t h , e v e n a s f a r a s t h e p o l a r a r e a s b o t h i n t h e n o r t h and t h e s o u t h . E n v i r o n m e n t h a s l o n g b e e n a n o b j e c t of s t u d y i n b i o l o g y and it is g r a t i f y i n g f o r t h e b i o l o g i s t s t h a t much of t h e work t h a t h a s b e e n d o n e , h a s now a c q u i r e d a much w i d e r s i g n i f i c a n c e . The i n v e s t i g a t i o n o f t h e r e l a t i o n s between o r g a n i s m s and t h e p h y s i c a l , c h e m i c a l and b i o l o g i c a l s t r u c t u r e i n which t h e y f u n c t i o n , which s i n c e a h u n d r e d y e a r s is c a l l e d e c o l o g y , i s now a wide s p r e a d o c c u p a t i o n . Not o n l y b i o l o g i s t s , b u t a l s o many o t h e r s b e g i n t o realise t h e i m p o r t a n c e o f t h i s d i s c i p l i n e f o r t h e f u t u r e of mankind.

I t i s much less s p e c t a c u l a r t h a n a s t r o n o m y w i t h its b r e a t h t a k i n g view o f t h e u n i v e r s e , o r t h a n molecular biology with its astounding i n s i g h t i n t o t h e working

of l i v i n g o r g a n i s m s . I t d o e s n o t r e q u i r e e x p e n s i v e o r c o m p l i c a t e d i n s t r u m e n t a t i o n . The r e s u l t s a r e o b t a i n e d m o s t l y by many y e a r s of p a i n s t a k i n g and o f t e n uno b t r u s i v e work, which d o e s n o t i m p r e s s t h e layman. But t h e r e s u l t s a r e of t h e u t m o s t i m p o r t a n c e f o r d e c i d i n g how we are g o i n g t o s h a p e o u r f u t u r e . One o f t h e c h a r a c t e r i s t i c s o f e c o l o g y is t h a t it r e q u i r e s a m u l t i d i s c i p l i n a r y a p p r o a c h a n d t h a t o n l y a wide knowledge of t h e i m p l i c a t i o n s o f d a t a from o t h e r d i s c i p l i n e s makes a d v a n c e s p o s s i b l e . The c o m p l e x i t y of t h e s u b j e c t a l s o makes t h e f o r m u l a t i o n of t h e p r o b l e m s more d i f f i c u l t t h a n i n m o n o d i s c i p l i n a r y re-

318

search. The 20-odd p a p e r s which h a v e b e e n p r e s e n t e d a t t h i s c o n f e r e n c e show t h i s a s p e c t c l e a r l y . They h a v e b e e n p r e p a r e d by s c i e n t i s t s f r o m w i d e l y d i f f e r e n t f i e l d s , t h e y a p p r o a c h t h e problem i n d i f f e r e n t ways and q u i t e o f t e n e x p l i c i t l y draw a t t e n t i o n t o t h e n e c e s s i t y o f i n t e g r a t e d s t u d i e s . I n t h e c o n t e x t of o u r c u l t u r a l h e r i t a g e i t is p e r h a p s t h e most a s t o u n d i n g f a c t t h a t w e have l e t t h e p o l l u t i o n of t h e a t m o s p h e r e c o n t i n u e t o s u c h a n e x t e n t t h a t o u r p r o u d l y c o n s e r v e d monuments are f a l l i n g t o p i e c e s a l l o v e r t h e w o r l d . The p a p e r s which e x p l i c i t l y a r e c o n c e r n e d w i t h t h i s item show t h a t we now know how s e r i o u s . is t h e damage t o o u r b u i l d i n g s and t o o u r a r c h i v e s , what t h e c a u s e s a r e a n d t h a t we must s t o p i t . The d e c i s i o n t o do s o now i s o u r s . A l l t h i s damage i s d u e t o a d i f f e r e n t a s p e c t o f o u r c u l t u r a l a c h i e v e m e n t s , which i s t h e s a t i s f a c t i o n of o u r u r g e n t w i s h t o i n c r e a s e o u r p e r s o n a l c o m f o r t : h e a t i n g when it is c o l d , c o o l n e s s when it i s warm, l i g h t when it is d a r k , t r a n s p o r t when w e need i t o r j u s t t h i n k it i s f u n t o t r a v e l a r o u n d , a n d a l l t h e i n s t r u m e n t a t i o n a n d g a d g e t s which make up s u c h a n e s s e n t i a l p a r t o f o u r d a i l y

life. W e t a k e t h e s e a l l f o r g r a n t e d a n d we d o n o t r e a l i s e how t h e i r p r o d u c t i o n a n d u s e r e q u i r e e n e r g y , and t h a t e n e r g y p r o d u c t i o n i s t h e main s o u r c e f o r t h e a i r pollution. \Ye a r e s o e a g e r t o m a i n t a i n and i n c r e a s e t h e q u a l i t y o f o u r l i v i n g c o n d i t i o n s

h e r e a n d now, t h a t we are n o t w i l l i n g , o r p e r h a p s I s h o u l d s a y n o t c a p a b l e of r e a l i s i n g t h e f a c t t h a t we a r e a c h i e v i n g r e s u l t s t h a t are s p l e n d i d i n t h e s h o r t

term view b u t w i l l b e c a t a s t r o p h i c i n t h e l o n g r u n . Mankind, i o r l o n g a g e s , h a s b e e n l i v i n g f r o m day t o day t r y i n g t o s t a y a l i v e and k e e p t h e i r f a m i l i e s a l i v e i n a v e r y h o s t i l e e n v i r o n m e n t . Even t o d a y f o r m i l l i o n s t h e f u t u r e d o e s n o t go much f a r t h e r t h a n t h e e f f o r t f o r t h e n e x t meal. T h i s h a s s t r u c t u r e d o u r way of t h i n k i n g s o s t r o n g l y t h a t i t t a k e s more t h a n o n e or two g e n e r a t i o n s t o l e a r n t h a t we must l o o k much f a r t h e r a h e a d . I t is n e c e s s a r y t o know what w i l l b e t h e consequences

in t h e f u t u r e of t h e things w e are doing t o d a y .

T h i s i s a p r o b l e m where o u r s o c i o l o g i s t s a n d p s y c h o l o g i s t s s h o u l d be u r g e d

t o make f u r t h e r s t u d i e s , i n t h e hope t h a t u n d e r s t a n d i n g why we behave a s we do, w i l l g i v e u s i n d i c a t i o n s how t o a l t e r our way

of living.

319 W e h a v e s e e n how bad t h e s i t u a t i o n is w i t h o u r c u l t u r a l e n v i r o n m e n t . Let u s now l o o k a t o u r n a t u r a l e n v i r o n m e n t .

I t is clear t h a t t h e two main t o p i c s f o r Northern-America and Europe a r e t h e

e know, of c o u r s e , t h a t t h e problem is much w i d e r t h a n l a k e s a n d t h e forests. W t h e s e two keywords s u g g e s t . The a c i d i f i c a t i o n of o l i g o t r o p h i c l a k e s and streams stems m a i n l y from s u l p h u r d i o x y d e - e m i s s i o n s from b u r n i n g f o s s i l f u e l s . O f c o u r s e d o u b t s have b e e n e x p r e s s e d w h e t h e r t h i s r e a l l y was t h e c a u s e . The main a l t e r n a t i v e s u g g e s t e d h a s been t h a t too l o n g c o n t i n u e d c u l t i v a t i o n or c h a n g e s i n t h e u s e o f c e r t a i n s o i l s , h a s b e e n t h e main c a u s e f o r a c i d i f i c a t i o n of n a t u r a l w a t e r s . It is now c l e a r t h a t t h i s is n o t t h e case. S u f f i c i e n t e v i d e n c e is a v a i l a b l e t o show t h e d i r e c t relat i o n b e t w e e n s u l p h u r d i o x y d e - e m i s s i o n s a n d a c i d i f i c a t i o n o f waterbodies. A l t h o u g h it was n o t m e n t i o n e d d u r i n g t h i s c o n f e r e n c e I draw y o u r a t t e n t i o n t o o n e p a r t i c u l a r item i n t h e p r o c e s s o f r e s o l v i n g t h i s q u e s t i o n . H y d r o b i o l o g i s t s have s i n c e long e s t a b l i s h e d t h a t t h e composition o f t h e m i c r o f l o r a of l a k e s d e p e n d s upon t h e a m o u n t s of n u t r i e n t s p r e s e n t a n d t h e a c i d i t y of t h e w a t e r . I n p a r t i c u l a r t h e Diatoms show t h i s r e l a t i o n q u i t e c l e a r l y i n t h e i r s p e c i e s c o m p o s i t i o n . These u n i c e l l u l a r p l a n t s h a v e s k e l e t o n s o f s i l i c i u m oxyde. When t h e y d i e t h e i r s k e l e t o n s s i n k t o t h e b o t t o m and r e m a i n t h e r e i n t a c t

f o r a v e r y l o n g time. By s t u d y i n g b o t t o m s a m p l e s t h e s e q u e n c e o f Diatom p o p u l a t i o n s c a n b e t r a c e d o v e r v e r y l o n g p e r i o d s . I n t h i s way it h a s b e e n e s t a b l i s h e d t h a t a c i d i f i c a t i o n does n o t c o r r e l a t e with changes i n a g r i c u l t u r a l p r a c t i c e but w i t h t h e i n c r e a s e of f o s s i l f u e l b u r n i n g . From a s c i e n c e p o l i c y p o i n t o f view t h i s is more s i g n i f i c a n t t h a n j u s t t h i s s t u d y itself i m p l i e s . Such s t u d i e s c a n o n l y be made by s p e c i a l i s t s i n Diatoms. T h i s s i l e n t g r o u p of t a x o n o m i c b i o l o g i s t s h a s b e e n w o r k i n g , h a r d l y n o t i c e d by t h e community a n d c e r t a i n l y n o t r e s p e c t e d a s i m p o r t a n t p e o p l e . Now t h e i r a c c u m u l a t e d knowledge h a s made it p o s s i b l e t o d e m o n s t r a t e a n i m p o r t a n t f a c t . It is a n u n e x p e c t e d a p p l i c a t i o n of what f o r a l o n g time had b e e n c o n s i d e r e d a p u r e l y scientific interest. And t h e n a g a i n j u s t i d e n t i f y i n g Diatoms is n o t enough. T h e s e s t u d i e s must b e combined w i t h t h o s e of s p e c i a l i s t s who may h a v e b e e n w o r k i n g on p o l l e n , or c l i -

320

m a t e , o r t h e h i s t o r y of a g r i c u l t u r e , or o n r a d i o c a r b o n d a t i n g . Only i n t e r d i s c i p l i n a r y e x c h a n g e of knowlegde c a n d e e p e n o u r i n s i g h t i n what is g o i n g o n a r o u n d us. Once h a v i n g e s t a b l i s h e d t h a t SOz is s u c h a n i m p o r t a n t f a c t o r , t h e q u e s t i o n a r i s e s : where d o e s it come from. The t r a n s b o u n d a r y t r a n s p o r t of a i r - p o l l u t a n t s h a s b e e n e s t a b l i s h e d a s a f a c t a n d t h e q u a n t a t i v e d a t a are becoming more a n d more precise. T h i s is a p r o b l e m f o r t h e p o l i c y - m a k e r s .

W e know t h a t c e r t a i n t h i n g s are hap-

p e n i n g , b u t we d o n o t y e t know how t o c o p e w i t h t h e s i t u a t i o n . The M i n i s t e r i n h i s o p e n i n g s p e e c h f o r t h i s c o n f e r e n c e d r e w a t t e n t i o n t o t h i s p o i n t . The d a t a a r e t h e r e with s u f f i c i e n t accuracy t o be a b a s i s f o r a p o l i t i c a l solution. T h i s c o n f e r e n c e h a s a s a n o v e r a l l t i t l e " A c i d i f i c a t i o n " and we u s e t h e word e a s i l y a l t h o u g h n o t always a c c u r a t e l y . T h i s should n o t obscure t h e f a c t t h a t our p r o b l e m is n o t j u s t t h e a c i d i t y a l o n e , b u t t h a t it i s a v e r y c o m p l i c a t e d q u e s t i o n w i t h a g r e a t many d i f f e r e n t a s p e c t s . A p a r t from t h e d i r e c t r e l a t i o n between water and air, also, the soil is an imp o r t a n t s u b j e c t f o r o u r c o n s i d e r a t i o n s . And s o i l i s a n e x t r e m e l y c o m p l i c a t e d sy-

stem w i t h p h y s i c a l , c h e m i c a l a n d b i o l o g i c a l components and a l l t h e i r p l u r i f o r m interrelations.

S o i l s d e v e l o p from w e a t h e r i n g r o c k s a n d t h e r o c k t h u s is of p r i m e i m p o r t a n c e f o r t h e s o i l which it g e n c r a t e s . The r e a c t i o n of t h e s o i l t o a c i d i f i c a t i o n dep e n d s t o a l a r g e e x t e n t upon t h e c o m p o s i t i o n o f t h e u n d e r l y i n g r o c k . I n t h e S c a n d i n a v i a n c o u n t r i e s t h e r e c e n t l y d e v e l o p e d p o s t - g l a c i a l s o i l s and

waters a r e much more s e n s i t i v e t o a c i d i f i c a t i o n t h a n many o f t h e C e n t r a l - E u r o p e a n s o i l s , which a r e d e r i v e d from more b a s i c r o c k s . As you have h e a r d , i n t h e n o r t h e r n p a r t o f E u r o p e i t is t h e w a t e r s t h a t s u f f e r most. I n t h e more c e n t r a l p a r t it w i l l b e t h e s o i l s which f i r s t show t h e n e g a t i v e e f f e c t s o f a c i d d e p o s i t i o n . P a r a l l e l s i t u a t i o n w i l l no d o u b t b e f o u n d i n North-America. O b v i o u s l y t h e a t t e m p t s a t t h e r e s t o r a t i o n of t h e damage w i l l h a v e t o be d i f f e r e n t i n t h e d i f ferent areas. T h e r e is a time l a g i n a l l t h e s e p r o c e s s e s . Not o n l y d o e s it t a k e time f o r t h e damage t o manifest itself c l e a r l y , we now a l s o know t h a t e v e n i f we r e d u c e

321

t h e amount of acia p r o d u c t s which are e m i t t e d i n t o t h e a t m o s p h e r e , it w i l l n o t h a v e a d i r e c t e f f e c t o n t h e water a n d even l a t e r

3n t h e s o i l . Because of j u s t

t h i s time l a g it becomes t h e more u r g e n t t o a c t a s s o o n a s is p o s s i b l e . P e r c o l a t i n g w a t e r g e t s i n t o a q u i f e r s a n d o t h e r u n d e r g r o u n d w a t e r b o d i e s and t h u s i n t o d r i n k i n g water. Through t h i s r o u t e human h e a l t h is d i r e c t l y t h r e a t e ned. Both i n s o i l s , i n c l u d i n g u n d e r - w a t e r s o i l s , and i n p i p i n g s y s t e m s , m e t a l s d i s s o l v e d u e t o t h e a c i d i t y of t h e w a t e r . P a r t i c u l a r l y a l u m i n i u m and c o p p e r a r e t h e o n e s most d a n g e r o u s l y i n v o l v e d . I t means t h a t t h e t o x i c i t y o f water c a n i n c r e a s e up t o a d a n g e r o u s l e v e l . I t i s t h e d i r e c t c a u s e of f i s h m o r t a l i t y and a p o t e n t i a l , i f n o t a c t u a l , d a n g e r f o r t h e h e a l t h of o t h e r o r g a n i s m s i n c l u d i n g man. As r e g a r d s forests it is much more d i f f i c u l t t o g i v e a d e t a i l e d p i c t u r e of

o u r knowledge. While o n t h e one hand i t is a g r e e d t h a t s o m e t h i n g u n i q u e and s p e c t a c u l a r is t a k i n g p l a c e i n l a r g e a r e a s o f t h e n o r t h e r n t e m p e r a t e z o n e , t h e r e is

some d i f f e r e n c e of o p i n i o n a s t o t h e i n t e r p r e t a t i o n of t h e phenomenon. A c c o r d i n g t o some w e s h o u l d b e more a w a r e o f t h e f a c t t h a t t h e r e is a c o n t i n u o u s p r o c e s s o f d e c r e a s e and i n c r e a s e i n t h e s t a t e of h e a l t h o f f o r e s t s , a pendulum of q u a l i -

t y which u n d e r l i e s t h e o b s e r v e d f a c t s o f t h e p r e s e n t y e a r s . As d a t a from r e s e a r c h , however, a c c u m u l a t e it becomes more and more clear

t h a t , t h o u g h t h i s may well b e a l e g i t i m a t e p o i n t o f v i e w , w e must a c c e p t t h a t now s o m e t h i n g o u t of t h e n o r m a l is t a k i n g p l a c e . T h e r e is now g e n e r a l a g r e e m e n t t h a t a i r p o l l u t i o n is t h e main c a u s e of t h e l a r g e scale d i e - b a c k o f t h e forests. But t h e r e are s t i l l q u i t e a number of i m p o r t a n t q u e s t i o n s t o b e a n s w e r e d . The r e l a t i v e s i g n i f i c a n c e of f a c t o r s i n v o l v e d is n o t a s s e s s e d i n t h e same way by different experts.

W e would l i k e t o g e t a n s w e r s t o o u r q u e s t i o n s q u i c k l y a n d a c c u r a t e l y . Unhapp i l y t h a t c a n n o t a l w a y s b e a c h i e v e d . T h e r e a r e t o o many e l e m e n t s i n v o l v e d ; d i f f e r e n t s p e c i e s of trees and o t h e r p l a n t s , d i f f e r e n t s o i l s and w a t e r r e g i m e s , climatic c o n d i t i o n s a n d a t m o s p h e r i c p r o c e s s e s make a n a n a l y s i s no e a s y m a t t e r and r e q u i r e time. A l l t h e same t h e p a p e r s a l r e a d y p r o v i d e u s w i t h a w e a l t h of i n f o r m a t i o n p r e s e n t e d d u r i n g t h i s c o n f e r e n c e , t o which I h a v e b e e n c o n t i n u o u s l y r e f e r r i n g a n d w i l l c o n t i n u e t o do so.

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Q u i t e c l e a r l y t h e r e are p e r i o d s of good g r o w t h a n d p e r i o d s of s t a g n a n t g r o w t t and h i g h e r m o r t a l i t y i n f o r e s t s d u e t o t h e v e r y i n t r i c a t e s y s t e m o f e x t e r n a l and i n t e r n a l r e a c t i o n s i n a l l t h e s e p e r a t e organisms involved.

The word stress h a s b e e n i n t r o d u c e d i n t h e p r e s e n t a t i o n s and it is a u s e f u l c o n c e p t . It d e n o t e s t h e f a c t t h a t we f i n d s i m i l a r phenomena i n trees and i n s t a n d s which c a n n o t a l w a y s be d i r e c t l y a s s i g n e d t o s p e c i f i c c a u s e s . D r o u g h t , h i g h water t a b l e , i n s e c t s , f u n g u s a n d b a c t e r i a l d i s e a s e s , g r a d u a l c h a n g e s i n t h e s o i l c o n d i t i o n a n d climatic v a r i a t i o n s a l l h a v e t h e i r i n f l u e n c e o n trees and t h e y e x e r t t h e i r i n f l u e n c e s i m u l t a n e o u s l y . A t t h e same time t h e s e d i f f e r e n t factors a r e i n t e r r e l a t e d i n a way which we d o n o t y e t c o m p l e t e l y u n d e r s t a n d . To a n a l y s e them, e x p e r i m e n t s h a v e t o b e p e r f o r m e d . Only a good s c i e n t i s t c a n i n t e r p r e t t h e -

se r e s u l t s f o r t h e b e n e f i t of e x t r a p o l a t i o n t o g e n e r a l c o n c l u s i o n s . To g e t res u l t s which have wide a p p l i c a t i o n we need v e r y e x t e n s i v e e x p e r i m e n t s w i t h a g r e a t v a r i a t i o n i n f a c t o r s a s r e g a r d s s o i l , c l i m a t i c factors a n d s p e c i e s o f plants. The v a r i a t i o n of r e s i s t a n c e t o n e g a t i v e effects h a s b e e n d i s c u s s e d . Although s e l e c t i o n of r e s i s t a n t v a r i a t i e s is a n e f f o r t we s h o u l d n o t n e g l e c t , it d o e s n o t seem t o b e a way t h a t w i l l s o l v e a l l o u r p r o b l e m s i n good time. Nuch o f t h e i n f o r m a t i o n p r e s e n t e d h e r e d u r i n g t h e s e d a y s shows t h e c o m p l e x i -

e c a n s t u d y t h e c o m p o s i t i o n a n d i n f l u e n c e of t h e s u r r o u n d i n g a i r i n which ty. W o p e n - t o p c h a m b e r s now p l a y a n i m p o r t a n t role. C o m b i n a t i o n s o f sulphur-oxidants l i k e ozone,

c a n b e i n t r o d u c e d i n t h e e x p e r i m e n t s , w h i c h , however, w i l l t a k e

many y e a r s t o c o m p l e t e . I n a number of c o u n t r i e s , i n c l u d i n g t h e USA, USSR and BRO,' o z o n e h a s b e e n shown t o b e a major f a c t o r . S u l p h u r - d i o x y d e a l o n e d o e s n o t g i v e t h e damage we o b s e r v e i n t h e f i e l d u n l e s s we u s e v e r y h i g h concentrations. But t o g e t h e r with n i t r o g e n - o x y d e s a n d h y d r o c a r b o n s i t d o e s . The c o m p l e x i t y of t h e s t r u c t u r e and f u n c t i o n o f p l a n t s makes it n e c e s s a r y t o p e r f o r m l o n g term e x p e r i m e n t s , u n d e r c a r e f u l l y c o n t r o l l e d c o n d i t i o n s . Only i n t h i s way c a n we u n r a v e l t h e p h y s i o l o g i c a l p r o c e s s e s . I t is n e c e s s a r y t o s t u d y t h e m i c r o s c o p i c s t r u c t u r e s i n which t h e s e p r o c e s s e s t a k e p l a c e a l s o . The s t r u c t u r a l c h a n g e s t h a t can be observed g i v e u s a b e t t e r p o s s i b i l i t y t o e x p l a i n what i s happening i n t h e p l a n t s . F u r t h e r t h e r e are t h e s o i l a n d i t s c h a n g i n g c o n d i t i o n s , t h a t have s t r o n g i n t e r c o n n e c t i o n s w i t h t h e p h y s i o l o g y of t h e p l a n t s . You must a l l o w me h e r e a g a i n

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t o draw a t t e n t i o n t o t h e f a c t t h a t o n l y d e c a d e s of f u n d a m e n t a l r e s e a r c h h a v e g i v e n u s t h e c o n c e p t s , knowledge and t o o l s t o a p p r o a c h t h e problem o f f o r e s t d i e b a c k i n a n a d e q u a t e way. The s o i l is a s y e t p o o r l y u n d e r s t o o d . W e need t o know more a b o u t t h e i n f l u e n -

ce of a c i d i f i c a t i o n o n t h e o r g a n i s m s i n t h e s o i l a n d t h e i r f u n c t i o n i n g . Our l a c k o f knowledge is a g r e a t d r a w b a c k , a s t h e s e b i o t i c e l e m e n t s a r e s o v e r y i m p o r t a n t i n s o i l processes, including t h e production of mineral n u t r i e n t s for t h e p l a n t s .

W e need a g r e a t w e a l t h of d a t a t o g i v e a more p r e c i s e e x p l a n a t i o n of what we obs e r v e , and t o b e a b l e t o f o r e s e e what w i l l b e t h e e f f e c t of o u r a t t e m p t s t o i m p r o v e t h e s i t u a t i o n . I n p a r t i c u l a r t h e r n y c o r r h i z a , s o i m p o r t a n t f o r many tree s p e c i e s , may s u f f e r c o n s i d e r a b l y from c h a n g e s i n a c i d i t y and changes i n the f u n c t i o n s of t h e s o i l u n d e r i n f l u e n c e of p o l l u t a n t s . I n some of t h e p a p e r s a t t e n t i o n h a s b e e n drawn t o t h e problem of how t o meae need s u r e items i n t h e b i o t i c and a b i o t i c components of o u r e c o s y s t e m s . W

s t a n d a r d t e c h n i q u e s w h e r e p o s s i b l e , w e need methods a p p l i c a b l e u n d e r v e r y d i v e r se c i r c u m s t a n c e s , we

p a r t i c u l a r l y need t e c h n i q u e s t o h e l p u n r a v e l complex pro-

blems.

W e h a v e b e e n t o l d q u i t e c l e a r l y i n t h e l a s t few y e a r s t h a t t h e d r y d e p o s i e now know a l s o t h a t d r y t i o n is a s i m p o r t a n t a f a c t o r a s t h e w e t d e p o s i t i o n . W d e p o s i t i o n may d i s s o l v e i n dew and t h u s create h i g h c o n c e n t r a t i o n s o f t o x i c components o n t h e l e a v e s a n d i n t h e r u n - o f f a l o n g t h e t r u n k o f t h e tree. Thus c o n s i d e r a b l e a m o u n t s o f t h e s e s u b s t a n c e s are d i r e c t l y t r a n s p o r t e d t o t h e s o i l . C o n s i d e r a t i o n h a s b e e n g i v e n t o t h e r e l a t i o n between n a t u r a l and man-made a c i d i f i c a t i o n . A l t h o u g h n a t u r a l a c i d i f i c a t i o n o c c u r s w i d e l y , t h e r a t e s are slow a s compared w i t h what man-made a c i d i f i c a t i o n is d o i n g now. The n a t u r a l p r o c e s s c a n n o t b e u s e d a s a n e x c u s e n o t t o do a n y t h i n g a b o u t o u r p o l l u t i o n . S u m a r i z i n g i t i s o b v i o u s t h a t a i r p o l l u t i o n is r e s p o n s i b l e f o r s u c h a m a j o r p a r t o f t h e damage t o t h e f o r e s t s t h a t f u r t h e r p o l l u t i o n s h o u l d b e s t o p p e d and t h a t it must s t o p s o o n . A s o n e s p e a k e r p u t it: "We s h o u l d n o t c o n t i n u e t o e x periment with nature". I n r e c e n t times we h a v e l e a r n e d t o u s e m a t h e m a t i c a l m o d e l s t o h e l p s o l v e p r o blems a n d h e l p f i n d p r a c t i c a l s o l u t i o n s , p a r t i c u l a r l y w i t h a view of f u t u r e d e -

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v e l o p m e n t s . T h a t i s t o s a y some o f u s have l e a r n e d t o work w i t h them, and o t h e r s , t h o u g h n o t c a p a b l e of b u i l d i n g them or h a n d l i n g them, h a v e l e a r n e d t o a p p r e c i a t e t h e i r v e r y g r e a t value. P a r t i c u l a r l y i n environmental problems modelling has h e l p e d a g r e a t d e a l t o clear o u r minds. I n t h e s e a r c h f o r ways t o r e s o l v e d i f f e rences i n f u t u r o l o g i c a l c o n s i d e r a t i o n s they a r e a n important tool.. Attention has been g i v e n t o its role i n o u r p r e s e n t concern and t h e c o n c l u s i o n s a r e important. They show u s what w i l l happen i f w e do n o t u s e t h e knowledge we have a v a i l a b l e , a n d how t h a t knowledge, if p r o p e r l y h a n d l e d , w i l l t e l l u s what t o do. Here a g a i n

we a r e q u i t e u n a v o i d a b l y c o n f r o n t e d w i t h t h e f a c t t h a t p o s t p o n i n g a c t i o n f o r t h e s a k e o f s h o r t term g a i n s w i l l l e a d u s t o a s i t u a t i o n w i t h s e r i o u s and o f t e n i r r e p a r a b l e l o n g term l o s s e s . T h i s b r i n g s u s t o t h e economic a s p e c t of o u r problem. S e v e r a l c a l c u l a t i o n s h a v e b e e n p r e s e n t e d . They a r e e s t i m a t e s a n d do n o t c l a i m p r e c i s i o n . The f i g u r e s a r e a l r e a d y c o n s i d e r a b l e and t h e t r e n d i n t h e estimates i s c e r t a i n l y a n i n c r e a s i n g one. T h i s s h o u l d b e e n e r g e t i c a l l y p u r s u e d b e c a u s e w e need more v a l u e s e x p r e s s e d i n money, b e c a u s e money is a word t h a t may c o n v i n c e t h o s e who have n o t y e t a p p r e c i a t e d t h e damage which is b e i n g d o n e .

We know now t h a t damage t o modern b u i l d i n g s and m e t a l c o n s t r u c t i o n s c a n be red u c e d w i t h g r e a t c o s t s by p r o t e c t i n g c o v e r s , b u t t h i s d o e s n o t h e l p u s much i n s o l v i n g t h e w h o l e of t h e p r o b l e m , t h e d a n g e r s f o r w a t e r , s o i l s , p l a n t s and human welfare. It d o e s h e l p u s t o r e a l i z e how e x t e n s i v e t h e o v e r a l l damage i s . The c o s t of t h e d i s t r i b u t i o n of l i m e w h e r e i t has b e e n a p p l i e d i n a g r i c u l t u -

re, forests a n d i n l a k e s i n c e r t a i n p a r t s o f S c a n d i n a v i a a n d e l s e w h e r e , a l r e a d y shows t h e amounts we h a v e t o s p e n d t o correct a f r a c t i o n of t h e damage which h a s b e e n i n f l i c t e d . The damage t o a g r i c u l t u r e is a l r e a d y e s t i m a t e d by some researc h e r s t o b e a b o u t 10%a n d i n a number of c a s e s up t o 40%, of t h e p o s s i b l e p r o d u c t i o n , t r u l y a t e r r i f y i n g f i g u r e . Long term s t u d i e s w i l l h a v e t o g i v e u s more p r e c i s e d a t a . B u t e c o n o m i c c o n s i d e r a t i o n s make it q u i t e o b v i o u s t h a t a n y s e n s i b l e a p p r o a c h w i l l h a v e t o b e i n t e r n a t i o n a l s o a s t o g e t maximum v a l u e f o r t h e national effort. One of t h e aims of t h i s c o n f e r e n c e is t o b r i n g t o g e t h e r r e s e a r c h - s c i e n t i s t s a n d p o l i c y - m a k e r s , w i t h t h e common c o n c e r n o f what t o d o a b o u t t h e p o l l u t i o n

of o u r e n v i r o n m e n t .

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A p r o b l e m t h a t t h e n p r e s e n t s i t s e l f is how t o t r a n s l a t e t h e r e s u l t s of res e a r c h i n t o d a t a that

p o l i c y - m a k e r s c a n u s e i n t h e i r work.

One p a r t i s t h e q u e s t i o n how t o use t h e so-called fundamental research. This e s s e n t i a l p a r t of what many of u s are t r y i n g t o a c h i e v e is o f t e n c o n s i d e r e d j u s t t h e hobby o f some u n r e a l i s t i c s c i e n t i s t of t h e o l d s c h o o l . It is s t r a n g e t h a t t h i s o p i n i o n s t i l l g o e s r o u n d , b e c a u s e s u f f i c i e n t e v i d e n c e h a s been p r e s e n t e d t o show t h a t t e c h n i c a l improvements i n o u r way of l i f e are b a s e d upon a p p l i e d s c i e n .

ce, which c a n n o t expand w i t h o u t f u n d a m e n t a l knowledge of p h y s i c s , c h e m i s t r y and b i o l o g y . The o b s e r v a t i o n t h a t s o c i a l s c i e n c e s c a n n o t a l w a y s h e l p t o a n s w e r q u e s t i o n s , t o some e x t e n t m i g h t b e d u e t o t h e f a c t t h a t t h e y h a v e n o t had time t o d e v e l o p t h e i r b a s i c s y s t e m o f t h i n k i n g . N a t u r a l s c i e n c e s , a s we now u n d e r s t a n d t h a t c o n c e p t , are some t h r e e c e n t u r i e s o l d , s o c i a l s c i e n c e s , however, only about t h r e e q u a r t e r s of a c e n t u r y . R e s t r i c t i o n of f u n d a m e n t a l s c i e n t i f i c r e s e a r c h is a p o l i c y which s t i l l p e r -

sists i n a number of c o u n t r i e s a n d w i l l , w i t h i n a d e c a d e , r e d u c e t h e p r o d u c t i v i t y of a p p l i e d s c i e n c e a n d t e c h n o l o g y . Those who come a f t e r u s w i l l n o t be g r a t e f u l for such a policy.

I would l i k e t o draw y o u r a t t e n t i o n t o o n e s p e c i f i c p o i n t . I t is t h e f u n d a m e n t a l d i f f e r e n c e i n ways o f t h i n k i n g b e t w e e n t h e s c i e n t i s t who p r o d u c e s t h e res u l t s a n d t h e p o l i c y - m a k e r , who h a s t o work w i t h t h e r e s u l t s of s c i e n t i f i c research.

For s c i e n c e i t is e s s e n t i a l t h a t t h e r e b e a d i v e r s i t y of o p i n i o n . It i s bec a u s e of d o u b t a b o u t a n a n s w e r t o a q u e s t i o n t h a t s c i e n c e a n d s c i e n t i t i c res e a r c h p r o c e e d . The moment t h a t d o u b t v a n i s h e s , t h a t p a r t of s c i e n c e s t o p s d e a d . The h i s t o r y of n a t u r a l s c i e n c e s shows u s how many u n c e r t a i n t i e s which seemed t o b e r e s o l v e d , l a t e r , o n closer s c r u n i t y , were shown t o b e u n c e r t a i n t i e s a l l t h e

same. The c o n s c i e n t i o u s r e s e a r c h w o r k e r is a l w a y s r e l u c t a n t t o s u p p l y s i m p l e quant i t a t i v e d a t a . He is aware of t h e c o n t e x t w i t h i n which s u c h d a t a are v a l i d . It

is h i s r e s p o n s i b i l i t y f o r t h e q u a l i t y of h i s d a t a that

makes him h e s i t a t e t o

come u p w i t h p r e c i s e v a l u e s . What h e h a s t o l e a r n is t o h e l p t h e p o l i c y - m a k e r t o i n t e r p r e t t h e s e d a t a i n t h e r i g h t way. T h i s i m p l i e s t h a t h e s h o u l d f o r m u l a t e p r e c i s e l y how f a r wrong h e c o u l c

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p o s s i b l y be. He c a n n o t a n d need n o t b e a 100% c e r t a i n . He w i l l have t o exp r e s s h i s o p i n i o n , s t a t i n g a s a c c u r a t e l y a s p o s s i b l e t h e r e l i a b i l i t y of h i s res u l t s . The e s t i m a t i o n o f a c c u r a c y is a n a c c e p t e d p a r t of s c i e n t i f i c p r o c e d u r e . The g i v e n d a t a s h o u l d b e f o r m u l a t e d i n s u c h a way t h a t t h e p o l i c y - m a k e r knows what h e i s g e t t i n g a n d what i t is worth.

It is w o r t h w h i l e m e n t i o n i n g t h a t t h e model-makers e x p l i c i t l y i n t r o d u c e

un-

c e r t a i n t i e s i n t o t h e p r e s e n t a t i o n of t h e i r r e s u l t s . I n t h e r e l a t i v e l y new f i e l d o f e n v i r o n m e n t a l r e s e a r c h t h i s phenomenon is o n l y too e v i d e n t . The c o m p l e x i t y of t h e p r o b l e m s

that range f a r i n t o t h e f i e l d s

of s o c i o l o g y , p s y c h o l o g y , m e d i c i n e a n d a l l n a t u r a l s c i e n c e s , m a k e s it d i f f i c u l t t o g i v e s t r a i g h t - f o r w a r d a n s w e r s t o sometimes s e e m i n g l y s i m p l e q u e s t i o n s . But d u r i n g t h i s c o n f e r e n c e w e h a v e a l r e a d y h e a r d a number o f more p r e c i s e v a l u e s which a c c o r d i n g t o t h e r e s e a r c h w o r k e r s w i l l h a v e t o b e minimum s t a n d a r d s f o r q u a l i t y or maximum v a l u e s f o r p o l l u t a n t s . I t i s worth n o t i n g t h a t t h e same a p p l i e s t o o t h e r f i e l d s of r e s e a r c h and t h e a p p l i c a t i o n of t h e r e s u l t s , a n d t h a t i n t h o s e f i e l d s w e have l e a r n e d t o l i v e with t h i s s i t u a t i o n . An e n g i n e e r who h a s t o b u i l d a b r i d g e , d e s i g n a b u i l d i n g o r l a y down a n a i r f i e l d , c a r e f u l l y c a l c u l a t e s h i s d e s i g n , i n t r o d u c i n g a l l t h e d a t a h e n e e d s conc e r n i n g t h e m a t e r i a l s a n d t h e c o n s t r u c t i o n t o b e rised, i n c l u d i n g o f c o u r s e t h e d a t a on t h e l o c a l s i t u a t i o n of t h e s i t e . Having done t h i s h e t h e n m u l t i p l i e s t h e outcome w i t h a f a c t o r 2 or 3 t o b e on t h e s a f e s i d e , and t h e n h a n d s i n h i s p r o j e c t . T h i s is q u i t e o p p o s i t e t o t h e r e a c t i o n of many who h a v e t o t a k e d e c i s i o n s c o n c e r n i n g t h e f u t u r e of o u r e n v i r o n m e n t . I f t h e c o n c l u s i o n of a s e r i o u s s t u d y r e s u l t s i n a c e r t a i n v a l u e t o b e r e a c h e d i n o r d e r t o o b t a i n a n a c c e p t a b l e sit u a t i o n p o l i c y - m a k e r s t e n d t o m u l t i p l y by f or e v e n less. They do s o a s t o obt a i n a v a l u e which c o n f o r m s t o what t h e y b e l i e v e c o u l d b e done. I t w i l l be one t h a t does n o t conform t o t h e r e l e v a n t d a t a of t h e r e s e a r c h . The r e s u l t is t h a t q u i t e g e n e r a l l y t h e m e a s u r e s of c o n t r o l of e n v i r o n m e n t a l s i t u a t i o n s f a l l f a r b e h i n d t h e n e c e s s a r y minimum. The F r e n c h h a v e a n a p p r o p r i a -

t e e x p r e s s i o n f o r t h i s way of t h i n k i n g : "Aprds nous l e d b l u g e " . It is b e c a u s e we a r e a p t t o l e t t h e s h o r t term f a c t s p r e v a i l o v e r t h e l o n g term c o n s e q u e n c e s .

327

I n o t h e r f i e l d s o f r e s e a r c h o n l a r g e scale p r o b l e m s , we f i n d a s i m i l a r s i t u a t i o n . I t a k e o n e example. I n economic s t u d i e s considerable m i s t a k e s a r e b e i n g made b e c a u s e of i n h e r e n t unc e r t a i n t i e s i n estimates of f u t u r e d e v e l o p m e n t s . Ten y e a r s a g o c o m p a n i e s a n d gov e r n m e n t s i n v e s t e d m i l l i o n s i n r e s e a r c h on a l t e r n a t i v e e n e r g y r e s o u r c e s : w i n d ,

solar e n e r g y , waves and t i d e s , b e c a u s e o f t h e r i s i n g o i l p r i c e s . Now b e i n g t a k e n u n a w a r e s , a n d n o t f o r e w a r n e d by t h e e c o n o m i s t s , o n a s p e c t a c u l a r f a l l i n o i l p r i c e s , much of t h i s i n i t i a l r e s e a r c h is b e i n g d i s c o n t i n u e d . I t r e s u l t s i n a n d e p l o r a b l e w a s t e of money a n d time, n o t t o s p e a k of t h e f r u s t r a t i o n o f t h o s e who had p u t t h e i r minds o n h e l p i n g s o l v e w h a t seemed u r g e n t p r o b l e m s . It i s g r a t i f y i n g t h a t a t l e a s t some r e s p o n s i b l e p e o p l e c o n s i d e r c o n t i n u a t i o n of t h a t k i n d of work w o r t h w h i l e . Now it i s q u i t e o b v i o u s t h a t a l o n g t e r m p o l i c y f o r t h e e n v i r o n m e n t c a n b e

b a s e d o n v e r y s o l i d p r o g n o s e s a s compared t o economic p r o g n o s e s .

W e know t h a t t h e e n v i r o n m e n t is s e r i o u s l y damaged by s u l p h u r d i o x y d e , n i t r o gen-oxydes a n d h y d r o c a r b o n s . W e know t h a t t h e e m i s s i o n of ammonia i n some areas

is a s e r i o u s t h r e a t t o p l a n t l i f e too. We know t h a t a l l t h e s e s u b s t a n c e s c a n b e r e d u c e d and we know t h a t t h e more we r e d u c e them t h e b e t t e r a r e t h e e x p e c t a t i o n s f o r t h e f u t u r e . I f you h a v e l i s t e n e d t o t h e p a p e r s p r e s e n t e d h e r e you must a g r e e t h a t t h i s 'is a f a i r d e s c r i p t i o n of t h e s i t u a t i o n . It is t h e message which t h e s c i e n t i s t s h e r e , a s s e m b l e d f r o m a l a r g e number o f c o u n t r i e s from Europe and N o r t h

America,have t o g i v e t o t h e p o l i c y - m a k e r s .

W e t r u s t t h e message w i l l b e u n d e r -

s t o o d and t h a t t h e i n t e r n a t i o n a l c o o p e r a t i o n f o r a c l e a r l y common i n t e r e s t w i l l b e promoted. It is w o r t h w h i l e t o d o s o m e t h i n g f o r t h e w o r l d w e h a v e i n t r u s t f o r f u t u r e generations.

T. Schneider (Editor)/Acidificationand its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

R E P O R T

R e p o r t of t h e INTERNATIONAL

CONFERENCE

organized b y t h e G o v e r n m e n t of THE NETHERLANDS

i n c o o p e r a t i o n w i t h the UNITED NATIONS ECONOMIC COMMISSION FOR EUROPE (ECE )

AMSTERDAM, 9 MAY 1986

331

332

I 1.

INTRODUCTION At the invitation of the Government of The Netherlands the first international Conference on Acidification and its Policy Implications, organized in cooperation with the United Nations Economic Commission for Europe was held in Amsterdam from 5 to 9 May 1986. The purpose of the Conference was, as described in paragraph 18 of the Resolution adopted at the Multilateral Conference on the Environment (Munich, 1984), to support the Executive Body of the Convention on Long Range Transboundary Air Pollution in its task by holding international symposia to discuss most recent scientific information related to acidification and long range transboundary air pollution and its policy implications.

2.

Representatives of the following Signatories to the Convention participated in the Conference: Austria; Belgium; Canada; Czechoslovakia; Denmark; Federal Republic of Germany; Finland; France; Hungary; Ireland; Liechtenstein; Luxembourg; Italy; Netherlands; Norway; Poland; Spain; Sweden; Switzerland; Turkey; Union of Soviet Socialist Republics; United Kingdom

;

United States of America; Yugoslavia and the European Economic

Community. 3.

Representatives of the secretariat of United Nations Economic Commission for Europe (ECE) and the United Nations Environment Programme (UNEP) attended the Conference; the following specialized agencies of the United Nations were present: United Nations Educational, Scientific and Cultural Organisation (UNESCO); United Nations Industrial Development Organisation ( U N I D O ) ; World Meteorological Organisation (WMO).

4.

Representatives of the Organisation for Economic Cooperation and Development (OECD), the Secretariat of the Nordic Council of Ministers and of the following non-governmental organizations also participated: International Union of Producers and Distributors of Electric Energy (UNIPEDE) and of the International Institute for Applied Systems Analysis

.

(IIASA)

5.

The Conference was further attended by approximately 120 observers in a personal capacity.

6. The Opening Session of the Conference was chaired by Dr.Ir.T.Schneider, Chairman of the National Organizing Committee. Mr.Schneider welcomed in particular Dr.P.Winsemius,

Minister of Housing, Physical Planning and

Environment of The Netherlands and Mr.K.Sahlgren, the United Nations Economic Commission for Europe.

Executive Secretary of

333

7.

In his Opening Address Minister Winsemius stated that this Conference, organized by the Government of the Netherlands in cooperation with the United Nations Economic Commission for Europe, resulted from the acidification conference held in Munich in June 1984 (Multilateral Conference on the causes and prevention of damage to forests and water by air pollution in Europe). The purpose of the conference is to make research results in the area of acidification available as quickly as possible and to make it possible to translate those results into policy. The results of this conference Conclusion from Munich

- must

-

as was intended in the 18th Final

support the work of the Executive Body for

the Convention (EB). The questions that are to be addressed, and that we hope to have answered or to bring closer to an answer in the conference summary and conclusions, are:

-

What directions are emerging in the research?

- Is there more certainty and new information over the extent of effects?

-

Is there more information about the causes; about the substances,

elements (for example, about nitrogen) that play a major role? Has the problem been sufficiently covered addressing just sulphur and nitrogen? Should hydrocarbons and ozone also be tackled?

-

Is there more clarity, more insight into the tempo with which the effects strike?

-

Does this force us to adjust the pace of the abatement effort?

Is there more clarity about the levels of these substances at which possible effects appear and the levels that are acceptable?

-

-

Is recovery of damaged ecosystems still possible? What is the situation with our cultural monuments? Is replanting the only hope for our forests? In that case, are temporary management measures possible and desirable? Minister Winsemius stated that almost ten years after the OECD report

"Long range transport of air pollutants", there is no doubt that acidification is a serious international problem laying responsibility on both science and politics. The question that is asked science is "what are the weakest links in the environment that w e must protect and how can

334

we do that?". The question that politics must answer is "are we willing to act?". It will always be true that our knowledge about the causes and effects of acidification is characterised by uncertainty. It is not sensible to postpone action until we have 99 percent certainty. That would probably be too late. We have to be willing to accept uncertainty and to institute measures sooner. Another problem is that sometimes control costs must be borne by one country, while another country is enjoying the benefits of the control. This can make a possible solution of the acidification problem more difficult. An international fund might provide a solution for this difficulty. Something similar has been mentioned by Dr.Steyrer Austrian Minister for Health and Environmental Protection

-

-

former

and Minister

Winsemius has been mentioning it on various occasions. The impression is that analogous ideas are also circulating in other Western European countries. Acidification is an international problem, urgently requiring international cooperation. It is clear that no matter where and how Europe is separated and unified - politically or administratively

-

the

environment binds us together. Air is the most rapid connection. Zt takes only a few days for the atmosphere to transfer the side effects of activities elsewhere. Minister Winsemius thought it admirable that

-

since the ECE

Convention on Long Range Transboundary Air Pollution was brought about in 1979 and entered into force in 1983

-

so much has been done

internationally in a fairly short time, thanks partly to the active secretariat of the ECE. The question remains, however, whether the pace of our international abatement effort is fast enough. It is of great importance to establish that as quickly as possible. The speedy transmission of information will help reduce our uncertainty about this. The first step in international control of acidification was taken in Helsinki last July with the signing of the protocol on the reduction of sulphur emissions or their transboundary fluxes. This step must still be taken for NO,. Minister Winsemius emphasized that NO, is a key component. It contributes to soil acidification and together with hydrocarbons is responsible for the formation of ozone. It will be especially important to learn the degree of NO, control desired because we are still at the beginning of the decision-making process. Research is underway among

335

experts that stresses the role of nitrogen in soil acidification more strongly. We know that products of photochemical air pollution, such as ozone, cause damage to vegetation. The damage from ozone

-

not only to forests

but also, for example, to agriculture and public health

-

is

considerable. Air pollution also damages the harvest. Minister Winsemius thought it surprising that this damage receives so little international attention. The reduction in crop yield in The Netherlands is estimated to amount to circa 5 percent. This means circa 250 million US dollars per year. Translated to the European scale, this would mean near an amount in the order of four thousand million 8.

US

dollar.

Mr.K.Sahlgren underlined in his statement that acidification is now recognized as a central environmental problem in the ECE region. It affects not only the material well-being through the deterioration of the natural resources on which that well-being depends freshwater

-

-

soil forests,

but also the cultural heritage, as historical buildings and

monuments are crumbling under the effects of atmospheric pollution. The initial focus under the Convention, Mr. Sahlgren said, has been on sulphur dioxide emissions as reflected in the protocol adopted in July 1985

in Helsinki on the reduction of sulphur emissions or their

transboundary fluxes by at least thirty per cent. Serious attention is now also being given to nitrogen oxides. Currently, data on air and precipitation quality from ninety six stations in twenty-four countries are reported to the European Monitoring and Evaluation Program (EMEP). Pending the entry into force of the Protocol for the long-term financing of the monitoring program, it is funded by voluntary contributions from

the parties to the Convention. It should be emphasized that the voluntary financial contributions for EMEP received so far have been sufficient to cover only the basic requirements of the agreed work plan. Besides the EMEP program, three further international co-operative programs for monitoring and assessment of air pollution effects, under the auspices of the Executive Body for the Convention, have been launched during the past six months. Initial progress on these three government-sponsored programs has been most gratifying. It illustrates the kind of “multiplier effect” which the Convention has triggered in international efforts to deal with the acid rain problem.

336

The on-going programs for implementation of the Convention have already resulted in a lively exchange of technological information and know-how, which is beginning to have its spin-off in commercial terms, especially in the field of East-West trade relations. The search is now on for the most cost-effective methods of pollution control

-

thereby

encouraging the export of specialized equipment and foreign licensing of new techniques. In this respect, the Executive Secretary recalled that air pollution control technology will be included among the subjects of the forthcoming ECE symposium on East-West business opportunities and trade prospects, to be held in Thessalonika (Greece) in September 1986. He pointed out that increased mobilization in market forces towards the achievement of the environmental objectives would lessen the need for coercion applied through governmental intervention. In concluding his statement, M r . Sahlgren said that the phenomenon of acidification and long-range air pollution has ceased to be confined to the ECE region alone. The countries of the region

-

after pioneering, so

to speak, the mass production and long-range export of acid precipitation

-

could also show the way towards effective international policies for

its control in other regions. I1 ELECTION OF OFFICERS 9.

Prof.Dr.D.J.Kuenen

(Netherlands) was unanimously elected Chairman.

Unanimously elected as Vice-Chairmen were: Dr.A.Ap1ing Mr.L.Bj5rkbom

(Sweden), Prof.Dr.B.Molski

(Hungary). Mr.W.J.Kakebeeke 10.

(United Kingdom),

(Poland) and Dr.L.Szabo

(Netherlands) was appointed as rapporteur.

During the first three days of the Conference twenty-one lectures were given reviewing the state of the art in the respective fields of acidification research. On Thursday representatives of Parties to the Convention presented their national research programs and policies regarding acidification.

III/IV REVIEW OF THE STATE-OF-THE-ART IN THE RESPECTIVE FIELDS OF ACIDIFICATION RESEARCH AND GENERAL SURVEY OF EFFECTS In the original report (par. 11-48) summaries of the papers were given. In these proceedings we would like to refer to the appropriate original papers giving the state-of-the-art in the respective fields of acidification research.

337

V SUMMARIES OF NATIONAL PRESENTATIONS AND ACCOUNT BASED ON THOSE PRESENTATIONS

In the original report (par. 4 9 - 6 9 ) only sumaries of the national contributions were given. In these proceedings we would like to refer to the original national presentations following this report. VI

ACCOUNT BASED ON THE PRESENTATIONS ON RESEARCH PROGRAMS AND POLICIES

REGARDING ACIDIFICATION 70.

The account below is based on the presentations by 2 1 countries and the European Communities. In their presentations to the Conference most delegates addressed policies to abate acidification effects. Several delegations described the results of their research programs on acidification. The plans for future policies and research were also presented.

71. All delegations stressed the importance of international cooperation

within the framework of the ECE-Convention on Long Range Transboundary Air Pollution. Furthermore, many delegations referred to the European Monitoring and Evaluation Program (EMEP) as a basic project under the Convention, producing very useful results for the signatories. 72.

Almost all delegations repeated their country's commitment to reduce SO2 emissions as laid down in the Protocol on the reduction of sulphur emissions by at least 30%. A few countries underlined the need to reduce SO2 emissions but pointed out for different reasons that they are yet in a position to sign the protocol. Some countries stressed the need for continued effort to develop and improve quantitative estimates of the extent of effects and of their amelioration following emission reductions. Several countries emphasized that 30% reduction is far from sufficient for reaching an ecologically sound environment, but only a first step. The ways in which countries aim to achieve reduction varied e.g. emission standards according to the best available technologies, ambient air quality standards and maximum sulphur content of fuels were mentioned.

73.

The role of nitrogen compounds in the acidification processes was frequently mentioned. Several countries also stressed the importance of NO, and hydrocarbons in the formation of ozone and other photo-oxidants

338

and their effects on forests and crops. 74.

Besides the effects of air pollutants which have been transported over a long distance, high concentrations from local sources with local effects were also reported. This includes the effects of ammonia in certain regions. Several countries mentioned the role of metals, especially aluminium,.in toxic concentrations both in surface waters and in soils.

75.

Regarding different types of damages some delegations reported recent figures of forest damage. Increased research efforts were frequently mentioned on effects of acidification in surface water, groundwater, forest soils, buildings and monuments. Actual types of damages vary markedly among countries.

76.

Most delegations highlighted past and present achievements in emission reduction. A few delegations pointed out that new emission control programs should not be implemented until a more adequate scientific and technical base was established. Other delegations held the view that reduction of various emissions is appropriate in view of the seriousness and irreversability of the observed effects, alt-houghgaps in knowlegde still exist.

77.

The determination of deposition target levels for sulphur and nitrogen was proposed by several countries. Necessary emission reduction can be derived from these levels.

78.

The need for further discussions and decisions about reduction of NOx emissions within the framework of the Executive Body was mentioned frequently. Reductions of 30% were suggested. Some countries will introduce US-standards for motor vehicles. Speed limits were also mentioned as useful preventive measures.

79.

Effects of nitrogen on the marine environment were mentioned by some delegations. Eutrophication of the Baltic Sea was considered of major concern by them.

80.

The Conference stressed that the present situation urges signatories to the Convention to intensify their cooperation in executing the principles laid down in the Convention. Especially the need of international research evaluation mechanisms was mentioned since a growing number of countries are working on monitoring and acidification research programs. Exchange of information will be useful to profit optimally from research

339

results and to avoid duplication of research efforts. It was suggested that in national acidification research programs, resources should be allocated for collaboration and for assessment of data originating from outside national programs. E l . Thanks were expressed to the Government of the Netherlands for the

initiative to hold the Conference in cooperation with the ECE in Amsterdam and it was complimented for the effective way the meeting was organized. The Conference was appreciated as very useful in reviewing the state-of-the-art in scientific knowledge in the field of acidification research. The Conference stressed that future exchange of information on the process of acidification and related subjects would be highly beneficial for all countries involved. VII 82.

GENERAL CONCLUSIONS On the basis of the scientific evidence brought forward at the Conference and the policy statements made by delegations, and bearing in mlnd the results concerning the abatement of air pollutants reached at the third session of the Executive Body of the Convention (Helsinki, 8-12 July 1 9 8 5 ) , the following general conclusions were agreed upon.

a.

The scientific evidence presented at the Conference confirmed that the primary cause of acidification') is

SOz.

It is also clear that NOx plays

a major role in acidification processes. In combination with hydrocarbons, NO, plays a major role in the formation of photochemical oxidants, especially ozone. b.

Acidification has widespread and in a number of cases irreversible effects on the environment and inflicts considerable economic losses and damage to the natural resource base and the cultural heritage of countries. Abatement programs implemented so far in Europe and North America have not yet led to sufficient reductions to protect the environment from acidification.

C.

11

Most delegates at the Conference stated that the Helsinki Protocol on the

In the view of some delegations it was preferred to add the words "due to air pollution"

340

reductiqn of sulphur emissions or their transboundary fluxes by at least 30 per cent is an important step forward to combat acidification of the

environment, but that this is not sufficient. Many countries have already announced further reductions. The above delegations recognized that further international cooperation, with more participating countries, is needed to achieve sound scientifically based environmental targets for acid deposition by further reduction of emissions or their transboundary fluxes. d.

The Conference agreed that the transboundary problems caused by NOx emissions can only be solved through international cooperation. The Conference welcomed the progress of the working group on NOx under the Convention. A number of delegates stated the need for a binding international agreement for the reduction of NO, and hydrocarbons. Awaiting such an international agreement, a number of countries have already found it necessary to take appropriate action. Some delegations considered that such action should take place after appropriate scientific investigations.

e.

To enlarge the basis f o r the verification of nationally adopted measures to reduce emissions of relevant air pollutants and to broaden the knowledge concerning effects on the most endangered components of the environment, in particular forests, lakes and other ecosystems, materials, historical monuments, and other cultural establishment of permanent integrated monitoring stations could be supported. To support the further elaboration of policy measures to reduce emissions, the interaction between scientists and policy makers should, for instance, be intensified.

f.

The inadequate knowledge of physiological processes in trees as caused by acidification and other processes requires increased research efforts. The results of these efforts should be made available to assist policy makers in further shaping abatement policies.

9. The exchange of information on research programs in existing

international fora should be intensified in order to minimize unnecessary duplication of research efforts and to facilitate the development of complementary research activities. This can help to increase the efficiency of acidification research and the use of funds available for such research. h.

To improve the data base for the development of dispersion and deposition models, it is recommended that national emission inventories be

341

established if this has not already been undertaken. This will facilitate a more accurate calculation of emission data, which will further increase both the comparability and quality assurance of data provided by countries and the value of models. Model projections can prove to be a valuable tool for policy makers in the development of national and international pollution abatement scenarios. i.

Given the imperative to minimize the effects of acidification in' Europe and North America in a way that will lead to environmental as well as financial-economic benefits for all countries involved, the development of innovative cooperative pollution abatement measures should be considered.

j.

In areas with relatively high ammonia emissions in particular from agricultural activities and to a certain extent in other areas, due i.a. to long distance transport, ammonia contributes to the acidification process. Therefore, increasing attention should be paid to monitoring of NH3, nationally and internationally, as well as to national abatement of

those emissions. k.

In case of historical monuments a special role is played by carbonaceous particles.

1.

It is recommended to further stimulate directly or indirectly the development of advanced technologies to combat air pollutants at the sources i.a. through support for basic scientific and technological research as well as the application of these technologies through demonstration projects.

m.

Consideration should be given to further ways of increasing the effectiveness of national long term policies and strategies to minimize the effects of acidification; including, e.g.,

the formulation of

appropriate deposition targets (for instance acid equivalent/unit of surface/year), and programmes to achieve them. n.

The Convention has proved to be an effective instrument for international cooperation to combat acidification and for the development of international agreements aimed at the reduction of air pollutants. Increased support for the execution of activities under the Executive Body and its subsidiary bodies is necessary.

0.

The effect of air pollutants on the environment is becoming a problem of the first order in a growing number of developing countries; assistance should be offered to those countries, based on experience gained in Europe and North America, to help them formulate their air pollution

342

abatement policies and strategies. VIII CLOSING REMARKS BY MINISTER WINSEMIUS 8 3 . Minister Winsemius closed the conference by evaluating its results

against the questions he had posed at the start. The conference proved to have provided new insights on many Increasing attention for NO,,

have provided new insights on many Increasing attention for NO,, in the soil in addition to

-

although not all

-

points.

hydrocarbons, ozone, and complex processes

SO2

-

although not all

-

points.

hydrocarbons, ozone, and complex processes was shown to be a clear tendency in

research programmes. Another striking development is the application of models which can quantify and simulate acidification. This is of great importance in judging whether we are headed in the right direction with control measures. In the research sphere, the need to strengthen research coordination was also striking. Concerning acidification's causes, it has become clearer that cannot be the only substance that causes the stated effects. NO,,

SO2

0 3 and

photo-oxidants also have a share in that. Levels at which effects occur have still been hardly presented. The Minister advised focussing attention on that in the research. It has become clear that the pace with which effects strike is probably faster than the tempo with which we are controlling acidification. It has been stated that recovery of trees and lakes degree

-

-

to a limited

has occurred in places where S O 2 emissions have been actually

reduced. In order to make recovery of ecosystems possible, further

SO2

reduction than has thus far occurred is needed and NO, and hydrocarbons will also have to be tackled. Temporary measures, such as liming acidified lakes, are very expensive and certainly needed, but do not offer a general solution. Given the points mentioned, the Minister concluded that the conference was cost-effective. Repetition can science and policy treaty.

-

through useful contact between

- be very meaningful

to stimulate execution of the ECE

343

IX ADOPTION OF THE REPORT 84.

During the closing session a number of amendments were introduced. They are reflected in the report and adopted by the Conference. The Conference agreed that a summary of Minister Winsemius's statement after the closure of the Conference be reflected in the report. On behalf of the participants Mr. Tarasti (Finland), chairman of the Executive Body asked Minister Winsemius to forward the report of the Conference to the Executive Secretary of the United Nations Economic Commission for Europe and to Governments, signatories to the Convention. He warmly thanked the Netherlands Government for having hosted a successful Conference.

T. Schneider (Editor)/Acidificationand its Policy Implications Elsevier Science Publishers B.V.. Amsterdam - Printed in The Netherlands

345

ACIDIFICATION POLICY AND RESEARCH I N FINLAND

ALEC ESTLANDER

M i n i s t r y o f t h e Environment, Box 306, 00531 H e l s i n k i ( F i n l a n d )

ABSTRACT A c i d i f i c a t i o n i s one o f t h e t o p p r i o r i t i e s f o r t h e a i r p o l l u t i o n a d m i n i s t r a t i o n i n F i n l a n d . A sulphur commission has been s e t up t o d e f i n e an optimal sulphur emission abatement p o l i c y , whereby sulphur emissions c o u l d be reduced by a t l e a s t 50 percent by t h e e a r l y 1990-ies from t h e l e v e l o f 1980. The o p t i m i z a t i o n has two dimensions: c o s t s and a i r q u a l i t y . The F i n n i s h A c i d i f i c a t i o n P r o j e c t e s t a b l i s h e d i n 1985 w i l l w i t h i t s annual budget o f some 10 m i l l i o n FIM e s t a b l i s h t h e knowledge b a s i s f o r f u t u r e emission r e d u c t i o n needs. I n t h e p r o j e c t t h e e x t e n t o f damage, e s p e c i a l l y on f o r e s t s and waters, i s surveyed and e f f e c t mechanisms a r e s t u d i e d as w e l l as abatement measures.

1. INTRODUCTION The l o n g range t r a n s p o r t o f a i r p o l l u t i o n has been f o l l o w e d i n F i n l a n d s i n ce t h e e a r l y 1970-s, and t h e e f f e c t s of a c i d i f i c a t i o n have been s t u d i e d extens i v e l y s i n c e t h e beginning o f t h e 1980’s.

Small l a k e s have been observed t o

have undergone a c i d i f i c a t i o n i n Southern Finland. The pH o f t h e l a k e s has c l e a r l y decreased, and seasonal changes i n pH have i n t e n s i f i e d . The i n f l u e n c e o f a c i d d e p o s i t i o n on t h e pH o f groundwater has n o t y e t been c l e a r l y demonstrated. The p o s s i b i l i t y o f f o r e s t s b e i n g damaged, which i s suggested by some r e searchers, i s regarded as a s e r i o u s m a t t e r i n F i n l a n d . Even though t h e amount o f a c i d d e p o s i t i o n i n F i n l a n d i s c o n s i d e r a b l y l e s s than i n Central Europe, b o t h t h e n a t u r e o f t h e bedrock and t h e c l i m a t e a r e f a c t o r s which may make t h e ecosystems i n t h i s c o u n t r y p a r t i c u l a r l y s u s c e p t i b l e t o damages caused by a i r p o l l u t i o n . The e f f e c t s o f p o l l u t a n t s which have accumulated i n t h e ecosystems i n small amounts may suddenly e x h i b i t e f f e c t s a f t e r a l o n g p e r i o d o f time.

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2. THE MEANS The A i r P o l l u t i o n C o n t r o l A c t came i n t o f o r c e i n F i n l a n d i n October o f 1982. A t t h e same t i m e a s t a t u t o r y o r d e r was issued which r e g u l a t e d more prec i s e l y t h e manner i n which t h e l a w was t o be implemented. T h i s law served as t h e b a s i s f o r two d e c i s i o n s i s s u e d by t h e Council o f S t a t e concerning t h e l e a d and benzene c o n t e n t o f p e t r o l and t h e g u i d e l i n e s on a i r q u a l i t y . The d e c i s i o n on t h e g u i d e l i n e s , i s s u e d i n June 1984. a l s o i n c l u d e s t h e goal t h a t , w i t h r e s p e c t t o e x t e n s i v e areas i m p o r t a n t t o f o r e s t r y o r a g r i c u l t u r e o r which a r e s i g n i f i c a n t from t h e s t a n d p o i n t o f n a t u r e conservation, t h e annual sulphur d i o x i d e c o n c e n t r a t i o n should n o t exceed 25, pg/m3, nor should t h e depos i t i o n of s u l p h u r i n areas of t h e aforementioned types exceed 0.5 grams o f sulphur p e r square meter annually. The M i n i s t r y o f t h e Environment was e s t a b l i s h e d i n October o f 1983. With i t was c r e a t e d t h e D i v i s i o n f o r a i r p o l l u t i o n c o n t r o l and n o i s e abatement.

The a c t , t h e M i n i s t r y and t h e d i v i s i o n c r e a t e d a s t r u c t u r e t o t a c k l e a i r p o l l u t i o n problems i n a much more e f f i c i e n t way. Measures t o reduce s u l p h u r emissions i n F i n l a n d have l o n g been under prepar a t i o n . I n December o f 1983 a memorandum was l e f t t o t h e M i n i s t r y o f t h e Environment by a task f o r c e on s u l p h u r surveys. T h i s task f o r c e drew up a programme t o i n v e s t i g a t e a l t e r n a t i v e s f o r r e d u c i n g t h e amount o f s u l p h u r e m i t t e d i n F i n l a n d and study t h e r e l e v a n t i s s u e s o f commercial, energy, and i n d u s t r i a l p o l i c y . The t a s k f o r c e a l s o recommended t h a t when t h e t e c h n i c a l and economic surveys had been completed a commission should be e s t a b l ished t o formulate t h e a c t u a l emission r e d u c t i o n p o l i c y . The t e n surveys i n c l u d e d i n t h e programme compiled by t h e task f o r c e were, f o r t h e most p a r t , completed d u r i n g 1984. 3. THE SULPHUR EMISSION POLICY

The s u l p h u r commission began i t s work i n February o f 1985. The commission i s t o draw up a proposal concerning t h e measures which would a l l o w a 30 perc e n t r e d u c t i o n i n emissions by t h e y e a r 1993, as w e l l as a proposal on how t h e goal o f r e d u c i n g emission by 50 percent o f t h e l e v e l which p r e v a i l e d i n 1980 c o u l d be r e a l i z e d d u r i n g t h e e a r l y 1990-s. The work o f t h e commission i n volves comparing o p t i o n s w i t h d i f f e r e n t concrete measures and combinations

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t h e r e o f . The e f f e c t s o f t h e measures w i l l be s t u d i e d e s p e c i a l l y i n two dimensions: c o s t s and a i r q u a l i t y . The c r i t e r i a f o r c o s t s i s t h e p r i z e o f reduced t o n o f s u l p h u r d i o x i d e emissions and f o r a i r q u a l i t y sulphur d i o x i d e l e v e l s i n c i t i e s and s u l p h u r d e p o s i t i o n . The commission w i l

deliver i t s f i n a l re-

p o r t i n September t h i s year. I n i t s f i r s t i n t e r i m r e p o r t i n May 1985 t h e commission c l a r i f i e d the manner i n which emissions o f s u l p h u r developed a t t h e beginning o f t h e 1980’s and assessed t h e l e v e l o f s u l p h u r emissions i n 1993. A d d i t i o n a l l y , t h e p o s s i b i l i t i e s o f i n s t i t u t i n g v a r i o u s measures t o f u r t h e r decrease these emissions were c l a r i f i e d , and a d e t e r m i n a t i o n was made o f t h e c o s t s involved. The comm i s s i o n has made a study of t h e p r e v a i l i n g q u a l i t y o f t h e a i r as w e l l as o f the manner i n which changes i n t h e emissions i n f l u e n c e i t . By 1993 emissions of s u l p h u r d i o x i d e i n F i n l a n d w i l l have undergone a con-

s i d e r a b l e r e d u c t i o n from t h e l e v e l which p r e v a i l e d i n 1980 (see t a b l e 1). Many f a c t o r s w i l l i n f l u e n c e t h i s development. The s t r u c t u r e o f energy product i o n c o n t i n u e s t o develop. The use of heavy f u e l o i l w i t h a h i g h sulphur cont e n t c o n t i n u e s t o decrease. O i l i s b e i n g replaced p r i m a r i l y by coal and peat, b o t h o f which have a r e l a t i v e l y l o w sulphur content, as w e l l as by n a t u r a l gas, which c o n t a i n s no sulphur a t a l l . i t i s p o s s i b l e t o f u r t h e r reduce t h e sulphur c o n t e n t o f t h e l i g h t f u e l o i l which i s r e f i n e d i n Finland. The use o f energy i s b e i n g i n t e n s i f i e d so t h a t i t s t o t a l consumption i s i n c r e a s i n g more s l o w l y than t h e p r o d u c t i o n o f t h e n a t i o n a l economy. Even t h e s t r u c t u r e o f t h e wood-processing i n d u s t r y i s changing. The use o f t h e c a l c i u m s u l p h i t e method i n t h e p r o d u c t i o n o f chemical p u l p i s becoming i n c r e a s i n g l y r a r e . Production p l a n t s i n o t h e r processing i n d u s t r i e s a r e a l s o b e i n g renovated and then

sul-

phur emissions can a l s o be reduced. F u l f i l l i n g t h e o b l i g a t i o n s contained i n t h e A i r P o l l u t i o n C o n t r o l A c t c o n t r i b u t e s c o n s i d e r a b l y t o a c h i e v i n g these goal s.

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TABLE 1 Summary o f t h e emissions f o r 1980 and 1983, and estimated emissions f o r 1993 w i t h o u t measures on t h e f u e l s i d e SOURCE OF EMISSION

EMISSION OF SO2

FUELS O i1 Coal Peat MANUFACTURE OF CHEMICAL PULP Sul phate p u l p Sul p h i t e p u l p Semi chemi c a l p u l p OTHER PROCESSING INDUSTRY O i l refining Basic chemical and metal indu s t r y Other i n d u s t r y Total Reduction compared t o 1980

1980 329,000 246,000 80,000 3,000 104,000 43,000 52,500 8,500 151,000 60,000

1983 171,000 119,000 46,000 6,000 75,000 41,000 24,000 10,000 111,000 34,000

1993 164,500 55,500 96,000 13,000 38,000 26,000 6,000 6,000 72,500 30,000

87,000 4,000

73,000 4,000

38,500 4,000

584,000 39 %

357,000

...270,000 ... 78,500 ...178,500 ... 51 000 ... 33,000 ... 7,000 ... 11,000

...393,500

275,000 53.

..

33 %

The goal o f t h e f i r s t phase, t h a t i s t o say, a permanent t h i r t y percent r e d u c t i o n i n s u l p h u r d i o x i d e emissions by 1993 imposes requirements on b o t h energy p r o d u c t i o n and t h e processing i n d u s t r y . With r e s p e c t t o energy p r o d u c t i o n a t h i r t y percent r e d u c t i o n presupposes the following:

1. A maximum o f 8.5 m i l l i o n tonnes o f c o a l w i l l be used annually,

and i t s

l e v e l o f s u l p h u r c o n t e n t w i l l n o t i n c r e a s e from t h e present l e v e l o f 0.8 p e r c e n t t o a n y t h i n g h i g h e r than 1.2 percent. 2. The t o t a l amount o f s u l p h u r d i o x i d e emissions a n n u a l l y caused by t h e use o f heavy f u e l o i l w i l l n o t exceed t h e f i g u r e caused by a consumption o f 1.6 m i l l i o n tonnes o f o i l w i t h a 3.0 percent sulphur content. 3. The p r o p o r t i o n assumed by n a t u r a l gas as a source o f energy w i l l increase

so t h a t i t corresponds t o a t l e a s t 1.6 m i l l i o n tonnes o f o i l e q u i v a l e n t s annually. 4. The sulphur c o n t e n t o f m i d d l e d i s t i l l a t e s ( l i g h t f u e l o i l and d i e s e l o i l )

i s n o t h i g h e r than 0.25 percent. 5. Use o f domestic f u e l s (wood, p e a t and r e f u s e ) increases t o the l e v e l o f 6.3 m i l l i o n tonnes o f o i l equivalents. With r e s p e c t t o t h e processing i n d u s t r y a t h i r t y percent r e d u c t i o n presupposes t h e f o l l o w i n g :

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1. The c a l c i u m s u l p h i t e method w i l l be used t o manufacture chemical p u l p a t no more than one f a c t o r y ( a l r e a d y achieved).

2. When f a c t o r i e s producing chemical p u l p have t o be renovated t h e d i r e c t evap o r a t i o n o f b l a c k l i q u o r w i t h combustion gases w i l l be replaced by o t h e r techniques, and t h e c o l l e c t i o n and t r e a t m e n t o f a l l s t r o n g l y odorous gases as w e l l as, t o a c o n s i d e r a b l e degree, o f weakly odorous gases, w i l l be i m p l emented. 3. I n t h e manufacture o f s u l p h u r i c a c i d , t r a n s i t i o n t o new technology w i l l be r e a l i z e d i n such a manner t h a t a t l e a s t two t h i r d s o f t h e s u l p h u r i c a c i d used w i l l be produced by t h e double c o n t a c t method.

4. A t o i l r e f i n e r i e s heavy f u e l o i l w i l l be p a r t l y r e p l a c e d by r e f i n e r y gases. 5. The sulphur c o n t e n t o f t h e ores used i n t h e i r o n and s t e e l i n d u s t r i e s w i l l decrease. 6. Sulphur emissions from o t h e r processing i n d u s t r i e s w i l l be decreased mak i n g use o f new process technology. These p r e r e q u i s i t e s t o a r e d u c t i o n o f sulphur emissions i n v o l v e , f o r t h e most p a r t , a c o n t i n u a t i o n o f s t r u c t u r a l developments which have already been implemented i n energy p r o d u c t i o n and i n d u s t r i a l processes, and f o r t h i s reason they do n o t r e q u i r e l a r g e separate investments f o r what c o u l d be regarded as expenses f o r a i r p o l l u t i o n prevention. A t t h e beginning o f t h e 1980’s more than F I M 5 b i l l i o n were i n v e s t e d i n measures which l e d t o s t r u c t u r a l changes, t h e r e s u l t o f which was p a r t l y a decrease i n sulphur emissions. Decreasing emissions o f sulphur d i o x i d e t o h a l f o f t h e l e v e l which p r e v a i l e d i n 1980 presupposes t h a t f u r t h e r measures be taken. A decrease o f 50 perc e n t w i l l be o b t a i n e d when:

-

t h e t o t a l amount o f sulphur d i o x i d e emissions from t h e use o f coal i s n o t g r e a t e r than emissions which correspond t o amounts o f c o a l s and t h e i r phur content as f o l l o w s :

consumption o f coal

sulphur c o n t e n t o f t h e coal

m i l l i o n s o f tonnes per annum

percent

5.6

1.0

7 .O 9.3

0.8

0.6

SUl-

350

-

t h e consumption o f heavy f u e l o i l w i l l decrease so t h a t i t s annual use

w i l l l e a d t o emissions corresponding t o 1.2 m i l l i o n tonnes o f o i l w i t h a 3.0 p e r c e n t sulphur content, o r t o 1.4 m i l l i o n tonnes o f o i l w i t h a 2.5 percent s u l p h u r content.No f u r t h e r u s e w i l l be made o f ores w i t h a h i g h sulphur c o n t e n t i n t h e p r o d u c t i o n o f i r o n and s t e e l

-

t h e gaseous emissions from t h e chemical wood processing i n d u s t r y w i l l be e f f e c t i vely treated. I n o r d e r t o ensure t h a t t h e d e s i r e d h a l v i n g o f emissions a c t u a l l y happens

several d e c i s i o n s which w i l l promote t h e r e d u c t i o n o f sulphur emissions w i l l be considered by t h e commission, such as l i m i t i n g t h e sulphur c o n t e n t o f f u e l s by t h e A i r P o l l u t i o n C o n t r o l Act, removing t h e sulphur from the combust i o n gases o f power and h e a t i n g p l a n t s , e s t a b l i s h i n g emission norms and specif i c d e c i s i o n s f o r t h e processing i n d u s t r y . The c o s t s a r i s i n g i n c o n j u n c t i o n w i t h these measures may be estimated on t h e b a s i s o f t h e surveys submitted t o t h e commission. Depending on t h e nature o f t h e measures taken, they range from FIM 3,000 t o FIM 12,000 per tonne o f sulphur removed.

I f i t was necessary t o reduce emissions o f sulphur d i o x i d e

by 100,000 tonnes annually, f o r example, t h e annual expenses would range from 200 m i l l i o n

FIM t o 600 m i l l i o n FIM, depending on t h e means used.

4. THE RESEARCH The F i n n i s h Government i n i t i a t e d a f i v e y e a r research p r o j e c t on a c i d i f i c a t i o n and a i r p o l l u t i o n a t t h e beginning o f 1986. The budget f o r 1986 i n c l u d e s a t o t a l a p p r o p r i a t i o n o f some 10 m i l l i o n FIM a n n u a l l y f o r f i n a n c i n g t h e proj e c t through two m i n i s t r i e s : t h e M i n i s t r y o f t h e Environment and t h e M i n i s t r y o f A g r i c u l t u r e and F o r e s t r y . The research program has been e n t i t l e d " F i n n i s h Research P r o j e c t on A c i d i f i c a t i o n " ( a b b r e v i a t e d from F i n n i s h name o f t h e proj e c t t o HAPRO). The p r o j e c t i s concerned with t h e development of a c i d i f i c a t i o n caused by sulphur and n i t r o g e n emissions and, more g e n e r a l l y , w i t h t h e problems associated w i t h a i r p o l l u t i o n . The aim o f t h e HAPRO p r o j e c t i s t o study cause-and-effect r e l a t i o n s h i p s in a i r p o l l u t i o n and, on t h a t basis: t o determine t h e e x t e n t o f r e g i o n a l e f f e c t s o f a i r p o l l u t a n t s i n F i n l a n d t o study whether t h e harmful e f f e c t s o f a i r p o l l u t a n t s a r e i n c r e a s i n g

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t o determine which areas and components o f t h e environment a r e being espec i a1 l y t h r e a t e n e d

351

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t o assess what measures would most e f f e c t i v e l y , and a t t h e l o w e s t costs, r e duce t h e harmful e f f e c t s o f a i r p o l l u t a n t s . Most o f t h e research work associated w i t h t h i s p r o j e c t i s being c a r r i e d

o u t i n t h e form o f i n d i v i d u a l s u b - p r o j e c t s a t research i n s t i t u t e s and u n i v e r -

si ties. The p r o j e c t i s b e i n g d i r e c t e d by an e x e c u t i v e working group w i t h t h e a s s i s tance o f a separate research d i v i s i o n .

A f u l l t i m e s e c r e t a r i a t has been appointed t o t h e p r o j e c t w i t h i n t h e Environmental P r o t e c t i o n and Nature Conservation Department o f t h e M i n i s t r y o f t h e Environment. The main p a r t o f t h e research i n t h e p r o j e c t i s c a r r i e d o u t i n t h e f i e l d s , o f f o r e s t and water e f f e c t s , which t o g e t h e r g e t some two t h i r d s o f t h e annual budget. The f i r s t r e s u l t s a l s o show a good reason f o r t h i s p r i o r i t y . F o r e s t e f f e c t s were e v a l u a t e d u s i n g needle l o s s i n c o n i f e r o u s t r e e s as t h e i n d i c a t o r . 2500 p l o t s , throughout Southern and Central F i n l a n d were studied, and a l s o undergrowth and s o i l f a c t o r s were included. The methods used a r e t h e same as i n t h e o t h e r Nordic c o u n t r i e s . According t o N o r d i c c r i t e r i a a t r e e i s damaged i f i t has l o s t over 20 perc e n t o f i t s needles. S l i g h t l y damaged (needle l o s s 21-40 percent) were 9 p e r c e n t o f t h e trees,

damaged (41-60 p e r c e n t ) one percent and severely damaged

(61-100 p e r c e n t ) a l s o one percent. Thus i n a l 1 , l l percent o f the t r e e s s u r veyed were damaged. As t o t h e causes o f t h e damages a l l s c i e n t i s t s do n o t agree. Most consider a i r p o l l u t i o n as a major reason, which t h e o r y i s supported by noted changes i n t h e undergrowth i n f o r e s t areas. Most o f t h e s u r f a c e waters i n F i n l a n d a r e l o w o f e l e c t r o l y t e s , brown c o l o r e d humic waters. C l e a r water l a k e s i n Southern F i n l a n d a r e i n general weakly b u f f e r e d . I n N o r t h e r n F i n l a n d (Lappland) t h e p r e v a i l i n g b u f f e r i n g c a p a c i t y i s c l e a r l y b i g g e r . The t o t a l sulphur d e p o s i t i o n i s about 1.5-1.8 Southern F i n l a n d and 0.6-0.3

g.S.m-*.a-'

!mOl.l-'

in

i n Northern Finland. The small

l a k e s i n Southern F i n l a n d have l o s t i n average 50 YnOl.l-', area even 90

g.S.m-'.a-l i n the coastal

o f t h e i r o r i g i n a l a l k a l i n i t y on t h e b a s i s o f f o u r d i f f e -

r e n t e m p i r i c a l and t h e o r e t i c a l methods. The survey o f about 8000 l a k e s has r e vealed about 500 l a k e s o f minimun pH < 5.0,

b u t i n Southern F i n l a n d 20-40 per-

c e n t o f a l l small f o r e s t l a k e s a r e a c i d i c . However, o n l y 150 o f these a c i d i c

352

l a k e s a r e c l e a r w a t e r l a k e s . Completely f i s h l e s s l a k e s have n o t been found i n t h e p r e l i m i n a r y survey o f 1 7 1 small a c i d i c f o r e s t l a k e s i n Finland. Therefore, i t seems t h a t a q u a l i t a t i v e age c l a s s a n a l y s i s can i n d i c a t e t h e e f f e c t s o f a c i d i f i c a t i o n on f i s h b e t t e r than a simple presence/absence r e l a t i o n s h i p . Comparing t o t h e o l d data s e t s c o l l e c t e d i n t h e 192O’s,

almost a l l monito-

r e d r i v e r s have l o s t p a r t o f t h e i r a l k a l i n i t y , p a r t i c u l a r l y i n s p r i n g . Small l a k e s have a general decreasing a l k a l i n i t y t r e n d over t h e p a s t 1 5 years. Sinki n g t r e n d s o f d i a t o m - i n f e r r e d pH from sediment cores a r e f a i r l y c m m n i n a c i d i c l a k e s i n Southern Finland, i n d i c a t i n g r e c e n t anthropogenic a c i d i f i c a t i o n . The a c i d i f i c a t i o n p r o j e c t i s c o n t i n u i n g a t l e a s t throughout 1989, probably w i t h a s l i g h t l y i n c r e a s e d budget. The t h r u s t o f research w i l l be t r a n s f e r r e d from e f f e c t surveys t o c a u s e - e f f e c t r e l a t i o n s h i p s . I n t e n s e i n t e r n a t i o n a l cont a c t s a r e a l s o foreseen.

T. Schneider (Editor)/Acidification and its Policy implications Elsevier Science Publishers B.V.,Amsterdam

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3 53

Printed in The Netherlands

Understanding Acidification; Objectives of the UK Environment Department's Research Programme. A.J. Apling Department of the Environment United Kingdom

Introduction Ideally, the basis for formulating policy on pollution issues is a complete understanding of each problem including;

.

identification of the damaging agents and the mechanism and extent of their impact.

.

identification of pollution sources and the mechanisms of transport, transformation and deposition of pollution between source and target.

-

evaluation of abatement options for both cost and benefit.

The Air Quality Management System approach discussed in session V of this conference, incorporating this understanding in a quantitative and mechanistic way, may then be used to quantify a range of policy options representing various levels of environmental benefit with their associated abatement costs. Our understanding of acidification of the environment remains, however, incomplete. This is not to say that air quality management models and systems should not be formulated nor policy objectives identified until every element of the acidification process is fully understood and quantified. A project with objectives in many ways similar in concept to the IIASA RAINS system, presented in Session V, is included in the UK Department of the Environment ' s own Research Programme. An important feature of the project is to include explicitly elements of uncertainty into the model. The UK has also announced policy objectives of 30% reductions in SO2 and NOx emissions by the end of the century. However, our ability to evaluate the consequences of actual or proposed policies will remain subject to considerable uncertainty until our understanding improves. The purpose of this paper is to illustrate some of the areas in which the Department's Research Programme seeks to fill the

354 need for more detailed understanding of acidification of the environment and its effects. The projects mentioned are part of the Environment Department's overall air pollution research programme, currently costing about E 4 M per annum. Appendix 1 lists those projects specifically related to effects. The Department's programme seeks to integrate its more applied projects with the basic research at Universities and research institutes, supported by Government funds, being carried out principally through the Natural Environment Research Council. Appendix 2 lists the effects related projects. The impor.tant work of the Energy Industries, with sponsorship from the Department of Energy, is also recognised. The Central Electricity Generating Board, for example, in the last year supported a programme of environmental impact research by about E5M.2 An important function of the programme is liaison and cooperation withotherwork, both in the UK and abroad. In this context we have already established arrangements to exchange details of research programmes with Government Departments and Agencies in the Federal Republic, Norway, Sweden, Finland and the USA. I would like to take this opportunity to invite other delegates at this conference to take part in similar exchanges of information. Identifying Key Research Areas. Air pollution problems demand an understanding of three basic components; atmospheric processes, effects and abatement. Prolects within our Research Programme cover all three areas. Almost all the research is carried out under contract by universities, research institutes and private sector consultants and the formulation of new contracts in the light of results obtained is an important method of identifying key research areas. International contacts also play a large part in determining the content of the Research Programme. In the context of acidification the Work Programme of the Executive Body for the ECE Convention on Long Range Transboundary Air Pollution is particularly important and the UK has played a full part in contributing to the work of the various groups. The Department seeks independent assessments of air pollution problems through Review Groups, composed of National experts, who review specific topics to agreed terms of reference and report with recommendations. The first such group to report was the Acid Rain Review Group,3 and the present structure of the UK acid deposition monitoring network is based on the Group's recommendations. Very recently, the Acid Waters Review Group 4 published its interim analysis of available data on the acidification of freshwaters in the UK. It identifies evidence for relatively recent acidification of freshwaters in a few geologically distinct areas of the UK, but also points to a past lack of good monitoring data specifically aimed at assessment of the problem as well as the potential importance of land-use practices in acidification. Other Review Groups due to report this year or early next year are concerned with the effects on terrestrial systems and buildings, and with the formation of photo-chemical pollutants.

355

In designing a research programme to reflect the key areas identified, the overall objectives remain the gathering of essential baseline data and the elucidation of those links in the chain between pollutant emission and environmental effects that remain poorly understood. Research Programme Projects on Acidification. Atmospheric Processes.

A comprehensive inventory of pollutant emissions is the essential basis for understanding acidification. The Warren Spring Laboratory of the UK Department of Trade and Industry, under contract to the Department of the Environment, has a central role in collating information on UK emissions and developing spatially and temporally disagqregated inventories. 5 These data have been used extensively in collaborative exercises with the UNECE and, through the OECD and EC, have formed part of the input data to the PHOXA programme described in Session V. Critical evaluation of emission factors, in particular for NOx and hydrocarbons, is necessary to improve our confidence in emission estimates. Warren Spring Laboratory has recently incorporated new performance related emission factors for motor vehicles in the National inventory as a result of the development of on-the-road inservice sampling systems. 6 Warren Spring is also the centre of national air pollution monitoring which is currently being expanded to provide comprehensive data on precipitation chemistry, NOx, SO, and ozone. 1986 will be the first complete year of operation of the new Acid Deposition network comprising nine primary sites with wet-only daily collectors and SO, measurement, and a 7 secondary network of some 60 sites with bulk rain collectors. Moni-toring is often regarded as a routine task, but for results to be worth while considerable effort and development is needed to ensure good quality control of data. Sample collection has also demanded new equipment development, particularly for the sampling of snow-fall.8 Networks of NOx, N O 2 , and SO2 measurement are now being established using totally remote, automatic operation which will build to a total of about 17 sites by 1987/88. As well as providing complete coverage of the whole of the UK, including the remote rural areas of Wales, Scotland and Northern Ireland, these networks will supply the necessary data for the planned expansion of the Europea!i Monitoring and Evaluation Programme, (EMEP), to include i.10, in 1986 and 0, in 1987. Many questions remain concerning atmospheric chemistry, in particular the reactions which govern the oxidation of SO, and NOx in the atmosphere. The Environmental and Medical Sciences Division at Harwell has been involved in the investigation of such reactions for many years. 9 The crucial role of hydroxyl radicals and hydrogen peroxide in converting SO, to sulphate is now well recognised and in addition to defining the reactions involved, Harwell has been developing measurement equipment for these species to enable the relationships between primary and secondary pollutants to be

3 56 observed in the atmosphere. Deposition of acidity at high altitude is poorly understood, involving as it does the conversion of sulphur and nitrogen oxides within clouds and precipitation. It is, however, of potential importance for upland forests and streams. To study the processes involved a series of field experiments at Great Dun Fell in Cumbria is being undertaken by the University of Manchester Institute of Science and Technology, Harwel1,the Universit of East Anglia and the Institute of Terrestrial Ecology. y o The peak of the Fell, at a height of 847111, is cloud-capped during some 200 days in the year and forms a natural laboratory where the chemistry of air pollutants can be followed as they pass through the cloud cap and into precipitation. The experiments include the detailed study of the pattern of acidic deposition and concentration at high altitude and the formulation of a mathematical model to describe the results. Mathematical modelling brings together our knowledge of emissions, atmospheric transport, transformation processes and mechanisms of deposition. The main thrust of modellin work in the Research Programme, also centred at Harwell, 17 has so far been summer photo-chemical episodes. By using modelling techniques which allow chemical mechanisms to be included in detail this work has shown among other things the potential for increased sulphate formation as a result of reductions in NOx emissions. More recent work on the development of N O x deposition models has indicated significant differences in deposition pattern from that for SO,. These modelling results have already been used in the ECE LRTAP N O x Working Group and through the OECD are contributing to the Netherlands/FRG PHOXA programme presented in Session V. The detailed photo-chemical modelling approach is an essential component in increasing our confidence in models to a level where they can be used for control strategy evaluation. Effects - Freshwater systems. The integrated study of freshwater catchments is central to our attempts to improve understanding of how water courses become acidified and the impact on freshwater biota. By comprehensive monitoring of complete catchments it is hoped to quantify the relative role of atmospheric acid input and of other influences, such as land use and management, soil type and history, and to estimate the effects of changes in these factors. The development of catchment classification and modelling techniques is a complementary part of this approach. There are four catchment studies within the programme, two being undertaken in collaboration with local Water Authorities. They range in size from catchments in South wales covering many hundreds of hectares and feeding the Llyn Briane reservoir, 1 2 to a 6.6 hectare catchment on a granitic outcrop at Charnwood in the English Midlands. l 3 Between them they cover water courses from small upland source streams which are most susceptible to the immediate effects of acid precipitation, through lakes in granitic basins to river systems which times of peak flow. l4 have shown the effects of h i g h a c i d i t y d u r i n g

357

The variety of land use represented includes moorland, afforested areas, agricultural land and managed uplands. The importance of soil type-and the effects of weathering, past management and groundwater flow are being intensive1 studied in catchment systems in Aberdeenshire, Scotland. The small catchment at Charnwood, by virtue of its convenient location, size and fast response to rainfall events can be very intensively monitored.13 This gives a detailed picture of the relationship of rainwater and stream quality during individual rainfall events and their impact on freshwater biota. Palaeoecological Studies, involving the study of lake cores for the remains of diatom populations, pollen, heavy metals and particles, enable the water quality history of water bodies to be assessed on a time scale of hundreds and even thousands of years, compared with the tens of years of direct water quality measurement. The work of Battarbee and his group at University College London, 1 6 initially supported by the CEGB, indicates that water bodies in geologically sensitive areas of South West Scotland have become acidified as a result of acid deposition since the Industrial Revolution. This work is now being extended within the Research Programme to include lakes in other parts of the UK, both to provide further tests of the method and to investigate the geographic extent of the phenomenon. The method has a precision of a year or two for the most recent sediment layers and may therefore be useful for indicating a response to reduced acid input by a method and on a timescale consistent with the long-term lake record. Effects

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Crops, Trees and Vegetation.

In contrast to the acidification of freshwaters, it remains open to question if acid deposition has any significant effect on the growth and yield of crops, trees or vegetation. The importance of factors, such as other air pollutants and the natural stresses of drought and temperature fluctuations, have always to be taken into account. Laboratory studies on the mechanisms of air pollution damage to trees and crops are carried out at Lancaster and Newcastle Universities. l 7 The response of plants to other stresses (low temperature, decreased levels of irradiance) and the potential for interaction with pollutant effects are important elements of the work. Chamber studies of effects on plants and trees are carried out at Nottingham and Lancaster Universities, at Imperial College London and at the Institute of Terrestrial Ecology, Edinburgh. 1 8 Both open top and closed chambers are used, the latter being specially designed to incorporate facilities for climate adjustment. The Nottingham open top chamber facility forms part of their lead role in the CEC COST 612 programme. These programmes also reflect the need to take into account not only pollutants in combination and their direct effects, but the possibility that pollutant exposure might predispose plants to injury through water or temperature stress. Field experiments with crop plants, growing as far as possible

358

under normal conditions, are carried out at Nottingham University, where cereal crops are fumigated with SO, in the field, and at Imperial College, where the emphasis is on ozone exposure, ozone and acid mist, and the combined effects of l9 urban pollutants on a wide range of crop and forage plants. Sensitive legumes are being used in a transect study of plant growth and yield carried out across Southern England. These approaches to evaluating the affects of air pollution on terrestrial systems represent an integrated approach designed to facilitate the transfer of quantitative dose-effect relationships from controlled experiments in laboratories and environmental chambers, through open-top chamber and field studies to estimates of effects on growing crops and trees. Forest Surveys in the UK have so far been carried out by the Forestry Commission. 2 0 Conifers were studied in 1984 and 1985 with a study of beech in 1985. Damage syndromes reported in the Federal Republic were not apparent in the UK trees surveyed. In 1986 the Department will be collaborating with the Commission in an extension of the annual survey to include deciduous species in hedgerows and amenity trees. Although not a direct part of the Research Programme, there are also strong links with the ITE and Lancaster University contributions to the Early Warning Forest Damage experiment of the European Community. 21 The interlinking of these programmes is important in ensuring that damage assessments are made using methods which are comparable throughout Europe. Studies of the decline of blanket peat bogs (ombrotrophic mires) by Dr. Lee at the University of Manchester 2 2 have highlighted a pollution related problem that particularly affects some upland areas of the UK. This work is important since it is one of the few cases where damage is related particularly to the nitrogen input from air pollution, of which the nitrate fraction of acid rain would form a part. Effects

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Buildings and Monuments

The Building Effects Review Group, which is due to report by the end of this year, is charged with reviewing the evidence for damage to monuments, buildings and building materials. An important question still to be answered quantitatively is the extent to which current pollution levels are causing damage and how far deleterious effects are the legacy of past pollution levels. The Building Research Establishment of the Department of the Environment plays a central coordinating role in the programme of research on buildings, monuments and materials. 2 3 Intramural work carried out at the Building Research Station includes controlled laboratory exposures on modern building materials, and environmental exposure with the National Materials Exposure Programme. This work provides the basis for an important input to the UNECE International Exposure Programme. The interaction of microclimate and air pollution is studied in projects at wells and Lincoln Cathedrals and at Bolsover Castle. The Establishment is also a centre of expertise on stone preservation techniques.

359

Among the extra-mural contracts coordinated by the Establishment are laboratory studies of pollutant effects on materials and a field study of damageto stone buildings situated along a transect in SE England covering a range of pollutant exposure conditions. Finally, the programme recognises the difficulty of assessing the scale and value of building damage and therefore includes a study of methodologies for assessing the building stock at risk from air pollution damage. Abatement The Department's programme on abatement and control does not at present include development of technologies. The important programme of the power generating industries and the Department of Energy is therefore briefly summarised here. The assessment of the suitability of existing technologies for abatement of pollution from UK sources is carried out by the enci users and the energy industries. In this, the Central Electricity Generating Board have a major effort. The development of new and improved technologies is sponsored principally by the CEGB, the National Coal Board, the British Gas Corporation and the Department of Energy. Atmospheric fluidised bed combustion systems have been developed and are available for industrial boilers and dryers. The main focus of current work is on the design, development and comparative assessment of advanced designs of power generation systems which hold promise of significant improvements in costs and in operating efficiency compared with present conventional plant equipped with flue gas desulphurisation. A major programme has been started on the development of a pressurised fluidised bed combustor, employing a heat exchanger immersed in the bed, with the addition of limestone sorbents for SO, capture. A design study is in progress on the use of PFBC systemsin conjunction with gas and steam turbines for power generation. British Gas has already developed to a commercial size a gasifier which abstracts the coal ash as a molten slag. A parallel study is being made for a power station using combined gas and steam turbines, using clean gas from this slagging gasifier. Compared with the desulphurisation of gases, the scope for economic sulphur removal from coal is limited, but research is being carried out on both the improvement of conventional coal preparation techniques and on the separation of a high sulphur stream from pulverised coal by high gradient magnetic flux. Substantial reductions of NOx emissions are now possible on new plant equipped with suitable new burners. Retrofitting of existing plant can however pose problems of corrosion and loss of efficiency and a stepwise approach is necessary to establish the operational limits with the different types of combustion equipment of UK power stations. Fiddler's Ferry power station has been equipped with low N O x burners as part of such a programme of testing and retrofitting. Trials will be extended to other power stations as the suitability of the equipment is

360

demonstrated. The Department's Research Programme focusses on assembling information on control and abatement technologies that can be used in evaluating strategies and policies. In order that the emission performance, environmental impact and cost implications of the application of abatement and low emission technologies can be evaluated, performance and cost estimates need to be available on a consistent and well defined basis. An agreed basis for such figures is not currently available, as pointed out in a recent OECD study. 2 4 As a first step in filling this need the Fellowship of Engineering is undertaking a review of abatement technologies with the central objective of deriving performance and cost information on a consistent and well defined basis. The study will include all the major sources of SO, and NOx emissions and is due to be completed in 1987. Summary and Conclusions. The Research Programme of the Department of the Environment seeks, in the context of other work going on in the UK and abroad, to improve our understanding of the phenomenon of acidification and its effects. The emphasis wherever possible is on quantification of processes which will enable the environmental benefits of emission changes to be assessed against their costs. In many areas, a better quantitative understanding should become available over the next 1-3 years, specifically; i)

Improved, disaggregated emission inventories will form a more reliable and detailed input for modelling studies.

ii)

Improved estimates of performance and cost for abatement technologies and low emission processes on a consistent basis will become available.

iii)

Comprehensive monitoring systems are being established, alongside similar systems in the rest of Europe, suitable for better defining the phenomenon of acid deposition and for validation of modelling programmes.

iv)

Improved mechanisms of pollutant transformation and deposition will be developed for inclusion in models.

V)

Large field experiments capable of testing models and the assumptions they incorporate are being undertaken. Integrated studies of land use, soil and freshwater systems and the development of catchment models should lead to better quantitative estimates of the contribution of acid deposition to freshwater acidity and hence the potential effectiveness of abatement and amelioration policies.

vi)

The detailed study of effects on crops, erees

361

and vegetation should clarify the relative importance of all stresses, both those due to pollution and those due to natural factors, and lead to realistic dose/effect relationships. vii)

Similarly reliable exposure/effect data for buildings and materials will become available.

viii) The improved data bases from the new monitoring and modelling programmes will allow dose/effect relationships to be translated into damage/cost estimates. The incorporation of these new, quantitative data into air quality management models is an essential step towards the goal of estimating the costs and benefits of abatement policies within defined confidence limits. References 1.

"Current Status of the United Kingdom Model for Economic Evaluation of Acid Deposition". E.B AIR/GE.2/R.11 ECE LRTAP, Group of Experts on Cost and Benefit Analysis, 2nd Session, Geneva 29-31 Oct. 1985.

2.

"Follow-up to the Environment Committee Report on Acid Rain", House of Commons, First Special Report from the Environment Committee, Session 1985-86. Publication HC51, London, HMSO.

3.

"Acid Deposition in the United Kingdom", United Kingdom Review Group on Acid Rain, Stevenage, Warren Spring Laboratory, 1983.

4.

"Acidity in United Kingdom Fresh Waters". United Kingdom Acid Waters Review Group, Interim Report, Departments of Environment and Transport Publication, London 1986.

5.

"Digest of Environmental Protection and Water.Statistics", No. 8, 1985, Department of the Environment, London, HMSO, 1986.

6.

Rogers, F.S.M., "A Revised Calculation of Gaseous Emissions from UK Motor Vehicles". Stevenage, Warren Spring Laboratory, Report LR508(AP) 1984.

7.

Irwin, J.G. "Acid Deposition in the UK", Environmental Health, 1985, 93, 212-220.

8.

9.

Barrett, C.F., Goldsmith, A.L., Hall, D.J., Irwin, J.G., "Variation of Precipitation Composition with Altitude : A Feasibility Study", Stevenage, Warren Spring Laboratory, Report No. LR534(AP), 1985. Cox, R.A., Penkett, S.A., "Formation of Atmospheric Acidity", in Proceedings of the Commission of the

362

European Communities' Symposium. "Acid Deposition : A Challenge for Europe". Karlsruhe, 19-21 September 1983. 10.

Choularton, T.W.C. et al, University of Manchester Institute of Science and Technology - in preparation. Fowler, D. et a1 Institute of Terrestrial Ecology, - in preparation.

11.

Derwent, R.G., HOV, 0. "The Potential for Generating Secondary Pollutants in the Atmospheric Boundary Layer in a High Pressure Situation Over England". Atmos. Environ. 1982, 16, 655-665.

12.

Stoner, J . H . , Gee, A.S., Wade, K.R. "The Effects of Acidification on the Ecology of Streams in the Upper Tywi Catchment in W. Wales". Environ. Pollut. Series A. 1984, 35, 125-157. Stoner, J.H., Gee, A.S. "The Effects of Forestry on Water Quality and Fish in Welsh Rivers and Lakes". J. Inst. Water Engs. Scientists. 1985, 39, 27-46.

13.

Black, V . , University of Technology, Loughborough, Private Communication

14.

Prigg, R.F. "The Effect on Juvenile Salmonidae of Biologi-. cal Quality of Upland Streams in Cumbria with Particular Reference to low pH Effects". N . W . Water Authority Rivers Division, report BN 77-2-83, 1983.

-

Sutcliffe, D.W., Carrick, T.R. "Acidity and Alkalinity of Water Bodies in the English Lake District". Windermere : Freshwater Biological Association Leaflet. 1985. 15.

Cresser, M . S . , Edwards, A.C., Ingram, S., Skiba, U . , Peirson-Smith, T. "Soil-Acid Deposition Interactions and their Possible Effects on Geochemical Weathering Rates in British Uplands". J. Geolog. SOC. (In Press).

16.

Battarbee, R.W., Flower, R . J . , Stevenson, A.C., Rfppey, B., "Lake Acidification in Galloway" : a Palaeoecological Test of Competing Hypotheses", Nature, 1985, 314, 350-352.

17.

Pande, P.C., Mansfield, T.A., "Response of Winter Barley to SO, and NO, Alone and in Combination". Environ. Pollut. A , 39, 382-29.

18.

Lane, P.I., Bell, T.N.B. "The Effects of Simulated Urban Air Pollution on Grass Yield : Part 1. Description and Simulation of Ambient Pollution. Part 2. Performance of Lolium Perenne, Phleum Pratense and Dactylus Glomerata Fumigated with SO,, NO, and/or NO". Environ. Pollut. B 8, 245-263, A, S,97-124.

19.

Baker, C.K., Colls, J.J., Fullwood, A.E., Seaton, G.G.R. 'Depression of Growth and Yield in Winter Barley Being Exposed to Sulphur Dioxide in the Field' (In Preparation).

363 Ashmore, M.R. "Effects of Ozone on Vegetation in the United Kingdom", Proceedings, International Workshop on "The Evaluation and Assessment of the Effects of Photochemical Oxidants on Human Health, Agricultural Crops, Forestry, Materials, and Visibility" Ed. P. Grennfell. Gothenburg : Swedish Environmental Research Institute, 1984. 20.

Binns, W . O . , Redfern, D.B., Rennolls, K., Betts A.J.A., "Forest Health and Air Pollution, 1984 Survey" Forestry Commission Research and Development Paper No. 142. Alice Holt; Forestry Commission, 1985.

21.

"Early Diagnosis of Forest Decline with Reference to Atmospheric Pollutants". Institute of Terrestrial Ecology and Lancaster University. CEC contract ENV. 3 V 0904. 1985.

22.

Press, M.C., Woodin, S.J., Lee, J.A., "The Potential Importance of an Increased Atmospheric Nitrogen Supply to the Growth of Ombrotrophic Sphagnum Species". New Phytologist, 1986 (In Press).

23.

Butlin, R.M., Cooke, R.J., Jaynes, S.M. Sharp, A.S., "Research into Limestone Decay in the United Kingdom", Proceedings, Fifth International Congress on Deterioration and Conservation of Stone, Laussane.1985. Vol. 1, 537. Butlin, R.M. "Effects of Acid Deposition on UK Buildings. Proceedings, 52nd Conference of the National Society for Clean Air : Scarborough 1985.

24.

"Understanding Pollution Abatement : Cost Estimates". OECD Environmental Monograph No. 1. Paris : OECD 1986.

364 Appendix 1 Acid Deposition Effects-Related Projects of the Department of the Environment's Air Pollution Research Programme. 1985/86. Research Project

Total Cost f

1.

The effects of acid rain on upland soils and streams.

244,200

2.

Chemical inputs from precipitation and their effect on a catchment.

129,000

3.

Effects of acidification on ,lakes and streams in Scotland.

147,000

4.

Effects of acid rain on plants and soils.

569,000

5.

Effects of afforestation and land management on the acidity of 5 catchments in Wales.

272,000

6.

Effects of acid rain on freshwater eco-systems in north-west England.

176,000

7.

Effects of acid deposition and photo-oxidants on trees.

184,000

8.

Aspects of pollutant attack on limestone buildings.

49,000

Degradation of building- materials in the presence of air pollution.

70,000

Identification and assessment of materials damage by air pollution.

25,500

11.

Effects of atmospheric nitrogen compounds on natural vegetation.

87,200

12.

Effects of low temperature fluctuation on the sensitivity of crops and trees to air pollutant damage.

67,000

9. 10.

13.

Effects of air pollution on metallic materials.

14.

Pollutant take-up and stone decay in southern Britain .

27,000

15.

Effects of acid deposition on vertical surfaces.

19,500

16.

Development of methodologies to evaluate stock at risk from air pollution.

10,700

Total

150,000

2,227,600

365 Appendix 2 Acid DepositLon Effects-Related Research Receiving Government Support. 1984/85. Project

Cost in 1984-85 E

Natural Environment Research Council. 1.

Acidification o f run-off from melting snow pack.

16,500

2.

Effects of ambient air pollutants on plant growth in and around London.

24,300

3.

Assessment of likely concentrations of toxic products of SO, and NOx fumigation of plants at their site of action.

4,400

Effects of gaseous pollutants on the interaction betwen plants and invertebrate herbivores.

3,600

Physiological effects of SO, pollution in water stressed plants.

6,000

4.

5.

6.

7.

Physiological Biochemical and ultra-structural role of calcium in the fills of freshwater teleosts and arthropods with respect to survival at low pH.

16,000

Interception of wind blown fog by vegetation and pathways for pollutant deposition.

13,700

8.

Chemical speciation of Aluminium.

9.

Diatom survey related to pH and water chemistry.

10.

Measurement of pH in freshwaters.

11.

Trophic relationships and effects of acid waters on stream invertebrates.

12.

Acid deposition and ground water.

13.

Effects of different forest canopies on the gross precipitation passing to the soil.

14.

Effects of acid precipitation on river catchments.

15.

Effects of polluted atmospheres on crops.

27,700 (50 per cent from EEC) 12,000 (50 per cent from EEC) 19,'OOO 15,000 9,000 (50 per cent from EEC) 29,000

(50 per cent from EEC) 23,700 (50 per cent from DOE) 102,000 (40 per cent from MAFF)

366 Project 16.

Interaction of airborne pollutants with natural surfaces in particular epicuticular wax of scots pine.

Cost in 1984-85 f

5,000

17.

Interaction of grazing and air pollution.

26,500

18.

Measurement of the rate of dry deposition of SO, on a Scots pine forest.

13,000

19.

Chemical composition of rainfall through Northern Britain.

33,900

20.

Effect of acid rain on the extension growth of Sitka spruce.

3,800

Influence of rainfall acidity on transport and exchange of gases between plants and atmosphere.

3,200

21.

22

-

23.

Hydro-chemistry of run-off from upland catchments.

26,500

Transient acid surges in upland streams.

54,000

Total

488,400

Scottish Office: acid deposition at L o c h Dee

75,000

Welsh Office: ecological monitoring of acid rain in Wales.

32,000

Ministry of Agriculture. Fisheries and Food: the response of barley to sulphur dioxide at concentrations controlled by fumigation.

65,200

Forestry Commission: effects of ambient levels of air pollution on tree growth in rural areas.

This work is being undertaken directly by the Forestry Conunission. The capital cost of equipment is f190,OOO and about 2% man years effort a year will be required.

*

367

T.Schneider (Editor)/Acidification

and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

EUROPEAN POLICY IN THE FIELD

ATROSPHERIC ACIDIC PRECIPITATION

OF

V. MANDL, Head of Division, Commission of the European Communities

200 rue de La Loi, 1049 BRUSSELS, Belgium

ABSTRACT

F o r e s t s i n t h e European Community a r e showing s i g n s o f c o n s i d e r a b l e damage S e v e r a l areas a r e which i s g e n e r a l l y a t t r i b u t e d t o a i r p o l l u t i o n . Whether t h i s r e f l e c t s d i f f e r e n c e s p a r t i c u l a r l y a f f e c t e d but others are less. i n t h e p e r c e p t i o n o f t h e problem, o r r e a l d i f f e r e n c e s i n e n v i r o n m e n t a l Monuments, s o i l and water a r e a l s o a f f e c t e d . conditions i s not clear. The Community has t h e r e f o r e t a k e n a c t i o n and major r e s o u r c e s have been mobilized, m a i n l y i n t h e framework o f Research, A g r i c u l t u r a l and Environmental P o l i c i e s . The need f o r c o o r d i n a t e d i n t e r n a t i o n a l a c t i o n on atmospheric p o l l u t i o n i s paramount and t h e Community w i l l c o n t i n u e i t s c o n s t r u c t i v e r o l e i n a wider i n t e r n a t i o n a l framework.

The p r e s e n t s i t u a t i o n Woodlands i n t h e European Community a r e showing s i g n s o f c o n s i d e r a b l e damage which i s g e n e r a l l y a t t r i b u t e d t o a i r p o l l u t i o n .

Areas o f t h e Community which

a r e p a r t i c u l a r l y a f f e c t e d i n c l u d e t h e Bavarian forest, t h e B l a c k Forest,

i n Germany,

r e p o r t e d i n Belgium,

Greece,

and t h e Vosges i n France. Italy,

s p e c i e s most a f f e c t e d a r e spruce,

fir,

t h e F i c h t e l g e b i r g e and Damage has a l s o been

Luxembourg and t h e Netherlands.

The

p i n e and beech.

Many s t u d i e s have been c a r r i e d o u t i n r e c e n t y e a r s t o d i s c o v e r t h e causes o f t h e damage and t o f i n d s y l v i c u l t u r a l remedies.

The s t u d i e s show t h a t t r e e s

a r e d y i n g because o f t h e combined e f f e c t o f s e v e r a l h a r m f u l f a c t o r s ,

among

which a i r p o l l u t i o n appears t o p l a y a key r o l e . F e r t i l i z a t i o n t r i a l s have shown t h a t a p p r o p r i a t e q u a n t i t i e s of m i n e r a l s can increase t h e resistance o f t r e e stands factors.

to air

p o l l u t i o n and o t h e r s t r e s s

368 it i s

Given t h a t broad-leaved woodlands such as beech and oak are a l s o dying, n o t c e r t a i n t h a t broad-leaved

species o f f e r b e t t e r long-term

resistance t o

a i r o o l l u t i o n than conifers. The s i z e o f t h e problem The e f f e c t o f a c i d d e p o s i t i o n and r e l a t e d processes on crop and f o r e s t growth have r e c e i v e d p a r t i c u l a r attention, out.

and numerous studies have been c a r r i e d

Only i n t h e Federal Republic o f Germany have r e g u l a r n a t i o n a l f i e l d

surveys been conducted although i n o t h e r Member States p e r i o d i c evaluations have been made a t contradictory,

regional or

national

Many of

level.

the

r e s u l t s are

even when d i f f e r e n t survey teams have examined t h e same areas

and evidence. The problem o f

forest

damage by a c i d d e p o s i t i o n on

recognised i n t h e Federal Republic o f Germany.

any

scale was f i r s t

E a r l y i n t h e 1970s,

reports

amongst s i l v e r fir,

from Bavaria remarked on t h e h i g h incidence o f die-back

and by t h e mid 1970s s i m i l a r symptoms had been noted i n Baden-Wurtenburg. t h e e x t e n t o f damage and range of

Since then,

species a f f e c t e d appears t o

have increased d r a m a t i c a l l y . The e x t e n t o f damage elseuhere i n t h e Community i s l e s s c e r t a i n . this

reflects

differences

in the

perception

of

the

together

problem,

species

with

the

occurrence

of

ageing

forests,

t h e l a c k o f damage i n some other

are

Additionally,

real

t h a t a p a r t i c u l a r combination o f c l i m a t i c and s o i l conditions, make

p a r t i c u l a r l y s u s c e p t i b l e t o t h e e f f e c t s o f a c i d deposition. argued t h a t

or

I t has been suggested,

d i f f e r e n c e s i n environmental c o n d i t i o n s i s n o t c l e a r . f o r example,

Whether

traditionally

not

planted

in

some

woodlands

I t has a l s o been

regions i s because s e n t i t i v e the

most

vulnerable

areas.

recent research has shown t h a t ozone may be i n s t r u m e n t a l i n

causing f o r e s t damage,

and v a r i a t i o n s i n t h e e x t e n t

differences i n the incidence o f

o f damage may r e f l e c t

h i g h ozone concentrations

due t o c l i m a t i c

factors. Monuments,

s o i l and water a r e a l s o a f f e c t e d by a i r p o l l u t i o n .

The response t o these problems has been quick and major resources u i t h i n t h e framework mobi l i z e d .

of

Agricultural

Research

and

Environmental

Policies

have

been

369

Community Research Programme

I. Programme and General Outline Most aspects o f a i r p o l l u t i o n have been d e a l t w i t h by t h e European Community research

programnes

since

the

European

Community

has

been

involved

in

environmental research i n 1972. Up t o date,

fourth

one,

t h r e e environmental research programmes have been completed, which

is

the

logical

continuation of

the

others

has

submitted by t h e Commission t o t h e Council o f M i n i s t e r s f o r adoption.

a

been It i s

intended t o cover t h e p e r i o d 1986- 1990. A i r q u a l i t y i s one o f t h e most important areas t o be d e a l t w i t h w i t h i n t h e

general framework described above.

Although t h e occurrence

a c i d i c p r e c i p i t a t i o n had already

been taken

o f atmospheric

i n t o account previously,

the

Commission reviewed t h e research p r i o r i t i e s as a consequence o f d i s t u r b i n g r e p o r t s on

forest

dieback

i n Central

Europe and a l s o as a r e s u l t o f

the

conclusions o f t h e Symposium on A c i d D e p o s i t i o n h e l d i n Karlsruhe 1983. The Council

of

M i n i s t e r s adopted

i n March

1984 a r e v i s i o n o f

the t h i r d

Environmental Research Programme a l l o c a t i n g supplementary funds f o r research

i n t h i s area i n response t o an upgrading o f t h e i r p r i o r i t i e s t r i g g e r e d a l s o by considerable p u b l i c pressure. I t i s foreseeable t h a t

issues

within the

t h e same p r i o r i t y w i l l be g i v e n t o a c i d d e p o s i t i o n

framework

of

the

forthcoming

Research

and Development

Programne. An o u t l i n e o f t h e implementation o f t h e programme i s as f o l l o w s :

1.

promotion o f t h e c o o r d i n a t i o n o f n a t i o n a l research by means o f concerted actions,

b u t a l s o by more f l e x i b l e means,

hoc t a s k f o r c e s t o enhance s p e c i f i c ,

2.

granting of gaps

i n the

such as t h e establishment of ad

narrowly d e f i n e d aspects;

s e l e c t e d research c o n t r a c t s e i t h e r f o r p r o j e c t s which f i l l national

research programme o r

d e f i n e d major n a t i o n a l research e f f o r t s .

as

contributions

to well

370 Two concerted a c t i o n s cover t h e " a c i d d e p o s i t i o n " f i e l d :

i.

The physico-chemical behaviour o f atmospheric p o l l u t a n t s (COST 611 1;

ii. The e f f e c t s o f a i r p o l l u t i o n on t e r r e s t r i a l and a q u a t i c systems (COST 612). Both

concerted

Committee"

actions

are

managed

by

a

Community-COST

c o n s t i t u t e d by t h e r e p r e s e n t a t i v e s o f

"Concertation

t h e member s t a t e s w h i l e

working groups a r e e n t r u s t e d w i t h t h e s c i e n t i f i c tasks.

The Commission o f

t h e European Communities provides t h e s e c r e t a r i a t o f t h e concerted actions. I n a d d i t i o n t o t h e members o f t h e European Community, countries

which

are

involved

in

european

a number o f other

co-operation

in

the

field

of

s c i e n t i f i c and t e c h n i c a l research p a r t i c i p a t e i n t h e Concerted Actions :

-

Finland,

- Norway,

Norway,

Sweden and S w i t z e r l a n d i n COST 611 and

Sweden and S w i t z e r l a n d in COST 612.

The o b j e c t i v e

of

national level.

the

Concerted A c t i o n

is

to

coordinate

research,

at

a

I t i s a t o o l f o r analysing t h e experiences and t h e r e s u l t s

achieved by European research i n s t i t u t i o n s and f o r assessing t h e s t a t e - o f the-art.

As

a

result

priority

objectives

for

future

research

can be

es tab1 ished. To a v e r y l a r g e extent,

t h e g r a n t i n g of s e l e c t e d research c o n t r a c t s i s based

on t h e r e s u l t s o f t h e concerted actions. 11. Achievements and p e r s p e c t i v e s

1.

With regard t o t h e Concerted A c t i o n on "Physico-Chemical Atmospheric Pollutants",

enabled a sound i n t e r n a t i o n a l cooperation t o be achieved. knowledge

is

updated

Behaviour o f

t h e programme implemented s e v e r a l years ago has on

a

r e g u l a r basis;

gaps

recommendations f o r f u t u r e research a r e formulated.

are

The s t a t e of i d e n t i f i e d and

The r e s u l t s o f t h i s

concerted a c t i o n a r e recorded i n many r e p o r t s which a r e a v a i l a b l e on request.

371

I n order

to

establish

a

logical

link

between

the

physico-chemical

behaviour o f a i r p o l l u t a n t s and t h e i r e c o l o g i c a l e f f e c t s , that

a

comprehensive

qualitative

and

chemical environment o f ecosystems, t h e moment t h i s does n o t e x i s t . general

insuff.iciency

uhich some important

of

quantitative

i t i s necessary

knouledge

of

the

e s p e c i a l l y f o r e s t s i s avai table.

At

This gap i n knouledge i s p a r t o f a more

i n f o r m a t i o n on

the

cycles of

pathuays a r e i n s u f f i c i e n t l y

pollutants for

q u a n t i f i e d (e.9.

dry

d e p o s i t i o n o f NO and HN03). The d r y d e p o s i t i o n o f N-compounds needs t o be investigated,

even though

many f o r e s t s may r e c e i v e more n i t r o g e n than i n t h e past ( l e a d i n g perhaps to

a

longterm m o d i f i c a t i o n of

the functioning

of

the

ecosystems v i a

p e r t u r b a t i o n s o f n u t r i t i o n a l and physio t o g i c a t processes). The concentrations o f a i r p o l l u t a n t s i n t h e ecosystems a r e a l s o n o t w e l t knoun

although

this

is

a

prerequisite

uhen

gauging

their

possible

damaging e f f e c t s on p l a n t communities. The data on SOz,

and ozone a r e i n s u f f i c i e n t and sparse.

NOX,

p o l l u t a n t s such as peroxy a c e t y l n i t r a t e s and hydrocarbons, compound e t c .

t h e d a t a a r e p r a c t i c a l l y non-existant.

d i f f i c u l t t o investigate the o f ecosystem and further,

role o f

For o t h e r

organic lead

As a r e s u l t ,

it is

these components i n t h e f u n c t i o n i n g

t o assess t h e consequences o f these chemicals

on t h e s t a t u s o f t h e ecosystems.

2.

Since t h e Concerted A c t i o n on " E f f e c t s o f

A i r P o l l u t i o n on T e r r e s t r i a l

and Aquatic Ecosystems" uas o n l y s t a r t e d i n March 1984,

i t i s too early

t o draw any f i n a l conclusions e i t h e r on t h e state-of-the-art

o r on what

should be t h e main research i n t h e f u t u r e . Nevertheless, some

basic

a f i r s t a n a l y s i s has enabled t h e Commission t o determine gaps

in

the

knowledge and t o

grant

a number

of

research

c o n t r a c t s t o s c i e n t i f i c i n s t i t u t i o n s i n t h e Member States. Community A g r i c u l t u r a l P o l i c y

An

inventory

of

Community

atmospheric p o l l u t i o n , Council.

forests,

especially

regarding

damage

due

to

proposed by t h e Commission has been submitted t o t h e

P i l o t p r o j e c t s and s p e c i f i c experiences,

which u i l l c o n t r i b u t e t o a

372 b e t t e r understanding of proposal

as

uell

as

t h e d y i n g forest, the

creation

of

have a l s o been included i n t h i s an

Advisory

Committee

for

forest

p r o t e c t i o n a t t h e l e v e l o f t h e Community.

I n t h e meantime a p r e p a r a t o r y p r o g r a m e has already been started, order

to

proposed performed

assess

the different

inventory. in

some

Germany,

Belgium,

different

Member

methodologies

remote

A

selected

sensing

regions

and Luxembourg. States

of

the

of

mainly i n

u h i c h could be used f o r t h e

demonstrative

France,

the

project

Federal

has

been

Republic o f

Three prominent l a b o r a t o r i e s o f t h r e e

European

Community have

cooperated t h e i r

a c t i v i t i e s i n t h i s respect and have developed and t e s t e d an i n f r a - r e d a e r i a l photographic technique which promises t o be a r e l i a b l e method. Other p r o j e c t s on hand have been c a r r i e d o u t i n France and I t a l y i n order t o compare d i f f e r e n t sampling methods i n f u r t h e r a n c e o f t h e establishment o f t h e Community

I n f o r m a t i o n System.

Three

additional

projects

are

s t i 11 i n

progress. The Commission o f t h e European Communities has a l s o issued a manual i n a l l Community languages which g i v e s a d e s c r i p t i o n o f d i f f e r e n t damages t o f o r e s t and t h e i r c l a s s i f i c a t i o n according t o a j o i n t l y agreed scale.

This manual

has been d r a f t e d i n accordance u i t h t h e conclusion o f t h e expert group uhich met i n F r e i b o u r g o n Brisgau on t h e i n i t i a t i v e o f t h e Economic Commission f o r Europe.

A r e p o r t on a c t i o n already undertaken by t h e Member States together u i t h the p r e v i o u s l y mentioned

proposals and

p r o j e c t s should

contribute

to a

more

coordinated Commun it y approach t o f o r e s t damage. Regulatory Measures There a r e t h r e e main elements i n European Community's environment L e g i s l a t i o n i n respect o f atmospheric p o l l u t i o n .

1.

a i r - q u a l i t y standards s e t t h e o b j e c t i v e s which have t o be achieved;

373 2.

emission l i m i t s ,

3.

product standards which s e t out t h e p a t h f o r a c h i e v i n g these o b j e c t i v e s .

and

A i r q u a l i t y standards s e t t h e parameters w i t h i n which i n d u s t r y must operate

and d e f i n e t h e q u a l i t y of expect.

t h e environment which c i t i z e n s o f

t h e Community

These standards a r e o f a g e n e r a l n a t u r e and s e t out l i m i t and guide

values f o r t h e c o n c e n t r a t i o n o f a s p e c i f i c p o l l u t a n t i n ambient a i r . Up t o now standards have been agreed f o r SO2 p a r t i c u l a t e matter,

i n c o n j u n c t i o n w i t h suspended

NOx and lead.

Q u a l i t y Standards Simply s e t t i n g standards f o r t h e q u a l i t y o f t h e a i r i s n o t enough t o ensure t h a t t h e standards a r e met,

and met i n a way t h a t does n o t cause u n f a i r

c o m p e t i t i o n o r b a r r i e r s t o trade.

Member States have agreed on a number o f

o t h e r d i r e c t i v e s r e l a t i n g t o emission l i m i t s and product standards. Emission l i m i t s Industry,

i n c l u d i n g energy production,

p o l l u t i o n problem. many d i f f e r e n t

However,

processes

is an important c o n t r i b u t o r t o t h e a i r

i t i s c l e a r t h a t i n d u s t r y i s made up o f a great

and products which

emit d i f f e r e n t

substances t o

v a r y i n g degrees. Nevertheless,

a1 1 Member States agree t h a t

i n d u s t r i a l emissions

should be

c u r t a i l e d and t h e Council o f M i n i s t e r s has g i v e n i t s approval t o a general framework d i r e c t i v e r e l a t i n g t o emissions from i n d u s t r i a l p l a n t . This d e f i n e s t h e areas and substances which should be s u b j e c t t o c o n t r o l and a u t h o r i s a t i o n and s t e e r s i n d u s t r y i n t h e d i r e c t i o n o f W h i l s t i t does n o t s e t s p e c i f i c which follow-up

advanced technology.

l i m i t s i t does s e t out t h e framework w i t h i n

d i r e c t i v e s can be introduced and which can be aimed a t t h e

r e d u c t i o n o r p r e v e n t i o n o f p o l l u t i o n from s p e c i f i c sources. The f i r s t o f these follow-up

directives

i s c u r r e n t l y before Council and i s

concerned w i t h t h e l i m i t a t i o n o f emissions from l a r g e combustion p l a n t s .

374 Product Standards

I n t h e area o f product standards t h e example o f t h e motor v e h i c l e i s t h e one which immediately s p r i n g s t o mind.

Transport i s a major source o f p o l l u t i o n

and t h e Commission has d r a f t e d a d i r e c t i v e aimed a t f u r t h e r reducing gaseous emissions

from motor-vehicles

introduce

a draft directive

weighing up concerning t h e

to

3.5

tons,

and

r e d u c t i o n of

intends

to

b o t h gaseous and

p a r t i c u l a t e emissions f rorn d i e s e l powered vehicles. Other examples o f product standards a r e t h e d i r e c t i v e r e l a t i n g t o t h e lead content o f p e t r o l and t h e proposals t o f u r t h e r reduce t h e sulphur content of gas-oi 1. There a r e a number o f g e n e r a l p r i n c i p l e s u n d e r l y i n g a l l t h e d i r e c t i v e s .

1. F i r s t and foremost i s t h e p o l l u t e r pays p r i n c i p l e . 2.

Secondly t h a t use should be made o f t h e b e s t a v a i l a b l e technology, i n v o l v i n g excessive cost. i n interpretation,

not

T h i s second p r i n c i p l e i s open t o d i f f e r e n c e s

on which technology i s best, and what may

f o r example,

n o t be an excessive cost i n one country may w e l l be excessive i n another.

3.

The

directives

market,

based

should on

be

the

controlable,

widest

compatible

with

possible international

agreement and t h e i r implementation should be p r a c t i c a l . c l e a r then t h a t any d i r e c t i v e w i l l be a compromise,

the

internal

cooperation

and

I t w i l l be q u i t e

b u t t h i s does not

mean t h a t i t w i l l be i n e f f e c t i v e . It

is

also

clear

that

be taken

to

achieve

is

it

technology or procedure.

not

reasonable

to

prescribe

a certain

The aim must be c l e a r l y s t a t e d b u t t h e steps t o

this

aim

must

be

left

to

t h e various

national

governments. Con c 1us i o n s The problems o f sulphur dioxide, major concern. lakes,

Individually

n i t r o g e n oxides and a c i d d e p o s i t i o n a r e o f

or together they a c t t o a c i d i f y t h e s o i l and

i n h i b i t p l a n t growth and damage b u i l d i n g s .

The Commission's proposal

f o r reducing emissions from l a r g e i n d u s t r i a l p l a n t s i s s t i l l under discussion

3 75 i n t h e Council.

The adoption o f EEC proposals on v e h i c l e exhaust emissions

w i l l l e a d t o r e d u c t i o n s i n NOX and other p o l l u t a n t s .

These measures by

themselves may n o t be enough. I t i s d i f f i c u l t t o a t t r i b u t e t h e impairment o f t e r r e s t r i a l ecosystems which

have r e c e n t l y been observed o n l y t o a i r p o l l u t i o n .

A complex

network o f

causes may be i n v o l v e d i n c l u d i n g : -

- some m e t e o r o l o g i c a l events - long-term c l i m a t i c episodes -

-

p e s t s and v i r u s e s a c t i n g as primary o r secondary agents f o r e s t r y p r a c t i c e s e.g.

t h e former f o r e s t r y p r a c t i c e s o f grazing o r l i t t e r

remova 1. A wide

i n v e s t i g a t i o n i n t o these causes cannot be f u l l y developed w i t h i n a

s h o r t period.

The on-going

research programme w i l l be

considered as t h e

f i r s t s t e p towards t h e establishment o f a r e a l coordinated programme and w i l l p r o v i d e t h e s c i e n t i f i c b a s i s f o r a more complete e x p l a n a t i o n o f t h e c u r r e n t l y observed impairment o f t e r r e s t r i a l ecosystems. The need f o r coordinated paramount.

i n t e r n a t i o n a l a c t i o n on atmospheric p o l l u t i o n i s

The Community may,

conceivable,

put i t s own house i n order,

but

t h e Community w i l l a l s o need t o continue t o p l a y a c o n s t r u c t i v e r o l e i n wider i n t e r n a t i o n a l frameworks.

377

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

CANADA'S A C I D R A I N CONTROL PROGRAM Acid r a i n h a s been c a l l e d t h e g r e a t e s t e n v i r o n m e n t a l t h r e a t t h a t Canada has ever faced.

The r a i n s and snows t h a t were o n c e c l e a n s i n g a n d p r i s t i n e

h a v e now become, as a r e s u l t o f human a c t i v i t y , d a n g e r o u s l y e c i d a n d destructive.

S c i e n t i s t s have f i r m l y e s t a b l i s h e d t h a t t h e primary cause of

a c i d i f i c a t i o n is SO2, w i t h NOx e m i s s i o n s also a s i g n i f i c a n t f a c t o r . The main s o u r c e s o f s u l p h u r o x i d e e m i s s i o n s i n North America are c o a l - f i r e d power g e n e r a t i n g s t a t i o n s a n d n o n - f e r r o u s ore smelters.

The main

s o u r c e s o f n i t r o g e n o x i d e e m i s s i o n s are a u t o m o b i l e s and o t h e r v e h i c l e s . Acid p r e c i p i t a t i o n c a n h a v e many h a r m f u l e f f e c t s .

It can i n c r e a s e t h e

a c i d i t y of l a k e s and streams t o a p o i n t where f i s h and o t h e r a q u a t i c c r e a t u r e s s u c h as f r o g s and s a l a m a n d e r s c a n n o t r e p r o d u c e become e x t i n c t i n o v e r l y a c i d i f i e d b o d i e s of water.

-

ultimately, they

Acid r a i n c a n a l s o

i n c r e a s e t h e a c i d i t y of s o i l s and, p a r t i c u l a r l y i n combination with o t h e r a t m o s p h e r i c p o l l u t a n t s s u c h a s ozone, is s u s p e c t e d of s l o w i n g down t h e growth

r a t e o f trees or making them more v u l n e r a b l e t o d i s e a s e .

Acid r a i n e r o d e s

b u i l d i n g s and monuments, i n c l u d i n g t h o s e of c u l t u r a l s i g n i f i c a n c e , c a u s i n g m i l l i o n s o f d o l l a r s worth of damage a n n u a l l y . The f i s h e r y , t o u r i s m , a g r i c u l t u r e and f o r e s t r y r e s o u r c e s a t r i s k d u e t o a c i d r a i n s u s t a i n a b o u t 8% o f C a n a d a ' s Gross N a t i o n a l P r o d u c t . The e n v i r o n m e n t is i m p o r t a n t t o C a n a d i a n s f o r b o t h economic and s o c i a l reasons.

P u b l i c c o n c e r n f o r t h e q u a l i t y of t h e e n v i r o n m e n t h a s been g r o w i n g ,

a n d a c i d r a i n is now t h e i s s u e h i g h e s t o n t h e p u b l i c ' s e n v i r o n m e n t a l agenda. E a r l y w a r n i n g of t h e knowledge of the s o u r c e s and effects of a c i d r a i n

came fran C a n a d i a n s t u d i e s s t a r t e d i n t h e 1950's a n d 60's. m a j o r c o n c e r n was damage from l o c a l a i r p o l l u t i o n . Canada a n d t h e U.S.A. programs.

A t t h a t time, t h e

I n t h e e a r l y ~ O ' S ,b o t h

p a s s e d c l e a n a i r acts and implemented v a r i o u s c o n t r o l

A s a r e s u l t , SO2 e m i s s i o n s were r e d u c e d i n E a s t e r n Canada by a b o u t

27% between 1970 a n d 1980, w i t h c a n p a r a b l e r e d u c t i o n s i n t h e U.S.A.

378 However, i t was c l e a r i n 1980 t h a t measures t o reduce l o c a l p o l l u t i o n were n o t s u f f i c i e n t , and t h a t much o f the damage t o a q u a t i c ecosystems was due t o long-range sources.

t r a n s p o r t o f a i r p o l l u t a n t s , from b o t h Canadian and U.S.

A Memorandum o f I n t e n t was signed between t h e two c o u n t r i e s

agreeing t o n e g o t i a t e a transboundary a i r p o l l u t i o n agreement “ i n c l u d i n g t h e already s e r i o u s problem o f a c i d r a i n ” .

A working group o f s c i e n t i s t s under

t h e Memorandum e s t a b l i s h e d t h a t damage occurred where wet s u l p h a t e d e p o s i t i o n exceeded 20 kg/ha/yr

i n moderately s e n s i t i v e a q u a t i c ecosystems.

By 1984 i t was c l e a r t h a t t h e U.S.A.

would n o t be implementing an a c i d

r a i n abatement program so Canada decided t o proceed u n i l a t e r a l l y and t o s t r o n g l y support i n t e r n a t i o n a l e f f o r t s t o develop a s p e c i f i c agreement f o r

SO2 reductions.

By t h i s t i m e e s t i m a t e s showed t h a t 14,000

were a c i d i f i e d and over 300,000 change from a c i d d e p o s i t i o n .

l a k e s i n Canada

were v u l n e r a b l e t o chemical and b i o l o g i c a l

F i s h i n g , tourism, a g r i c u l t u r e , f o r e s t s and

p o s s i b l y human h e a l t h were a f f e c t e d .

I n response t o t h i s environmental c r i s i s , i n March 1985, Canada launched t h e most ambitious environmental proyram i n i t s h i s t o r y , based on a c a n b i n a t i o n o f good science and p o l i t i c a l commitment. The key components o f t h a t program are:

-

an a c i d r a i n p o l i c y based on a c h i e v i n g an environmental o b j e c t i v e , i s , no more than 20 kg/ha/yr

that

o f wet s u l p h a t e d e p o s i t i o n f o r moderately

s e n s i t i v e areas;

.

a commitment t o reduce sulphur d i o x i d e emissions i n e a s t e r n Canada by 50% by 1994;

. .

new motor v e h i c l e emission standards comparable t o U.S.

standards;

t h e l a r g e s t and most comprehensive s c i e n t i f i c research and m o n i t o r i n g e f f o r t ever undertaken by Canada i n t h e environmental f i e l d . e x p e n d i t u r e s equal $30 m i l l i o n or $1.20 p e r capita,

Current

w i t h more than $18

m i l l i o n c o n t r i b u t e d by t h e f e d e r a l government.

.

c o o p e r a t i o n among f e d e r a l and p r o v i n c i a l governments, and c i t i z e n s o f a l l ages.

the p r i v a t e sector

379 The C a n a d i a n c o n s t i t u t i o n , w h i c h d e f i n e s t h e f e d e r a l and p r o v i n c i a l j u r i s d i c t i o n s , r e q u i r e s a p a r t i c u l a r a p p r o a c h t o t h e a c i d r a i n problem.

In

Canada, t h e r e s p o n s i b i l i t y f o r r e g u l a t i n g s t a t i o n a r y s o u r c e s o f a i r p o l l u t i o n

rests w i t h p r o v i n c i a l g o v e r n m e n t s .

The r e s p o n s i b i l i t y f o r c o n t r o l l i n g

e m i s s i o n s from v e h i c l e s ( c a r s , t r u c k s and b u s s e s ) is a s h a r e d one:

the

f e d e r a l government d e f i n e s s t a n d a r d s a t t h e m a n u f a c t u r i n g s t a g e a n d p r o v i n c i a l g o v e r n m e n t s r e g u l a t e a n d i n s p e c t motor v e h i c l e s t h e r e a f t e r . transboundary a s p e c t s

-

i n t e r p r o v i n c i a l and i n t e r n a t i o n a l

o f p a r t i c u l a r i n t e r e s t t o t h e f e d e r a l government.

-

The

of a c i d r a i n a r e

Both l e v e l s o f government

a r e c o n c e r n e d a b o u t t h e economic a n d e n v i r o n m e n t a l damage b e i n g c a u s e d by acid rain. C a n a d a ' s e f f o r t s t o c o n t r o l a c i d r a i n are c o n c e n t r a t e d i n t h e s e v e n e a s t e r n provinces:

M a n i t o b a , O n t a r i o , Quebec, New Brunswick, Nova S c o t i a ,

P r i n c e Edward I s l a n d and Newfoundland.

Much o f t h e 502 p r o d u c e d i n Canada

o r i g i n a t e s w i t h i n t h i s a r e a and p r e v a i l i n g winds t r a n s p o r t t h e p o l l u t i o n t o w a r d s t h e e a s t e r n p o r t i o n s of t h e c o u n t r y . C a n a d a ' s g o v e r n i n g s y s t e m is o n e o f c o - o p e r a t i v e f e d e r a l i s m a n d t h e s t r e n g t h s o f t h a t s y s t e m h a v e now been b r o u g h t t o b e a r on t h e t h r e a t o f a c i d rain.

.

I n March 1984, f e d e r a l and p r o v i n c i a l e n v i r o n m e n t m i n i s t e r s a g r e e d t o a two-phase e m i s s i o n r e d u c t i o n program, c u t t i n g 1 9 8 0 SO2 e m i s s i o n s by 25% by 1990 and a f u r t h e r 25% by 1994.

Again, s c i e n t i f i c r e s e a r c h i n d i c a t e d t h a t

by c u t t i n g e a s t e r n C a n a d a ' s SO2 e m i s s i o n s by 50% ( o r t o 2.3 m i l l i o n t o n n e s p e r year b a s e d on 1980 e m i s s i o n s of 4.6 m i l l i o n t o n n e s ) and w i t h compatible emission r e d u c t i o n s i n t h e United S t a t e s , acid d e p o s i t i o n could b e l i m i t e d t o t h e a c c e p t e d (20 kg/ha/year)

t a r g e t i n many a r e a s .

To meet t h e 1990 g o a l , p r o v i n c i a l g o v e r n m e n t s i n O n t a r i o and Q u e b e c

r e g u l a t e d e m i s s i o n r e d u c t i o n s a t INCO ( S u d b u r y ) , O n t a r i o Hydro, Noranda (Rouyn) and Noranda ( M u r d o c h v i l l e )

.

.

I n F e b r u a r y 1985, a n a g r e e m e n t was r e a c h e d by t h e M i n i s t e r s o f t h e Environment of Canada, Manitoba, O n t a r i o , Quebec, New Brunswick, Nova S c o t i a and Newfoundland.

P r i n c e Edward I s l a n d s u p p o r t e d t h e i r d e c i s i o n s .

The a y r e e m e n t s p e l l e d o u t how much e m i s s i o n s w i l l b e r e d u c e d i n e a c h p r o v i n c e i n o r d e r t o meet t h e 1 9 9 4 t a r g e t d a t e .

The f e d e r a l and

p r o v i n c i a l governments f u r t h e r agreed to s u p p o r t f i n a n c i a l l y , to t h e

380 e x t e n t n e c e s s a r y , t h e abatement e f f o r t s needed t o meet em i ssi o n r e d u c t i o n targets.

.

One y ear ago, t h e f e d e r a l government agreed t o t i g h t e n s t a n d a r d s f o r au t o m o b i l e em i s s io n s .

The s t a n d a r d s , which w i l l have t h e e f f e c t o f

r ed u ci n g n i t r o g e n oxide e m is s i o n s by 45%, w i l l apply t o a l l new c a r s and l i g h t d u t y t r u c k s o f model year 1988.

High performance c a t a l y t i c

c o n v e r t e r s w i l l be n e c e s s a r y on a l l new 1988 model l i g h t - d u t y v e h i c l e s s o l d i n Canada.

The government is a l s o i n v e s t i g a t i n g t i g h t e r em i ssi o n

s t a n d a r d s f o r t r u c k s , b u s e s and o t h e r heavy v e h i c l e s . Each p r o v i n c i a l government now h a s i d e n t i f i e d t h e SO2 emission r e d u c t i o n s i t mu.st a c h i e v e t o s a f e g u a r d t h e Canadian environment from a c i d rain

-

and each h a s committed i t s e l f t o make t h o s e cuts.

The p r o c e s s o f

de v el o p i n g r e g u l a t o r y o r d e r s is underway. Quebec announced its e m i s s io n c o n t r o l p l a n s on February 8, 1985, modifying its Environmental Q u a l i t y Act.

These apply t o automobile

e m i s s i o n s , t h e combustion o f f o s s i l f u e l s , and s m e l t i n g o p e r a t i o n s . s u l p h u r em i s s i o n s w i l l be c u t back by 45% o v e r a l l .

Quebec's

In some cases, a c t i o n s

m u s t be i n i t i a t e d immediately t o respond t o t h e r e g u l a t i o n s .

.

e x i s t i n g co nti n u o u s r e a c t o r s m e l t i n g f a c i l i t i e s m u s t reduce SO2 e m i s s i o n s from 1980 levels by 35% by 1989 a n d 50% by 1990;

.

a l l o t h e r e x i s t i n g s m e l t i n g f a c i l i t i e s cannot emit more t h an 275 kilograms o f Sop p e r tonne o f m i n e r a l c o n c e n t r a t e ;

.

a l l new s m e l t i n g f a c i l i t i e s must c o n t r o l 95% o f t h e s u l p h u r co n t ai n ed i n t h e c o n c e n t r a t e o r o r e b e in g processed. The implementation of t h e s e r e g u l a t i o n s means t h a t Quebec w i l l have done

i t s s h a r e i n h e l p i n g Canada meet t h e 1994 r e d u c t i o n t a r g e t . The Government o f O n t a r i o launched its "Countdown Acid Rain" program i n December 1985.

The program c o n t a i n s s t i f f c o n t r o l s on s u l p h u r em i ssi o n s from

t h e p r o v i n c e ' s f o u r l a r g e s t p r o d u c e r s and g i v e s them s t r i c t , yet r e a l i s t i c , g u i d e l i n e s by which th e y a r e t o reduce d r a m a t i c a l l y by 1994.

By t h a t year,

O n t a r i o ' s p r o d u c ti o n o f SO2 w i l l b e 885 k i l o t o n n e s ( k t ) an n u al l y o r lower, down from 2,192 k t i n 1980.

The companies a f f e c t e d by t h e new c o n t r o l s m u s t

381 a l s o meet s t r i c t r e p o r t i n g d e a d l i n e s i n t h e i n t e r i m , s o t h a t t h e i r p r o g r e s s can be monitored. O n t a r i o ' s new p l a n is a n i n t e g r a l component of l a s t y e a r ' s f e d e r a l - p r o v i n c i a l agreement t o s l a s h e a s t e r n Canada's SO2 em i ssi o n s.

Since

O n t a r i o a l o n e is r e s p o n s i b l e f o r about 50% o f Canada's em i ssi o n s, t h i s new c o n t r o l program is a major b r e a k t h r o u g h i n t h e b a t t l e a g a i n s t a c i d r a i n . The c a p i t a l c o s t o f d e s i g n i n g and i n s t a l l i n g a c i d r a i n c o n t r o l measures t o r ed u ce em i s s i o n s by 502 is a b o u t $1.5 b i l l i o n , o f which $750 m i l l i o n may be s p e n t i n t h e n i c k e l and copper s m e l t i n g i n d u s t r y . I n d u s t r y h a s t h e primary r e s p o n s i b i l i t y f o r c a r r y i n g t h e s e c o s t s . F ed er al and p r o v i n c i a l governments have agreed t o p r o v i d e f i n a n c i a l a s s i s t a n c e t o t h o s e companies whose economic s i t u a t i o n d o es n o t p er m i t them t o b e a r t h e c o s t of p o l l u t i o n c o n t r o l s e n t i r e l y on t h e i r own. Other components of t h e a c i d r a i n c o n t r o l program i n c l u d e :

.

P r o v i d i n g $150 m i l l i o n f o r e m is s i o n c o n t r o l s a t smelters:

These f u n d s, t o

b e matched by t h e p r o v i n c e s , a r e t o b e made a v a i l a b l e t o i n d u s t r y f o r m o d er n i zat i o n i n i t i a t i v e s which i n c l u d e p o l l u t i o n c o n t r o l s .

.

As s u r i n g $25 m i l l i o n f o r t e c h n o l o g y development and d em o n st r at i o n a t

smelters:

t h e s e f u n d s have been e s t a b l i s h e d f o r smelter r e s e a r c h and

development, and are i n a d d i t i o n to a c a n p a r a b l e amount i n v e s t e d by s m e l t i n g companies.

.One example o f s u c h i n d u s t r i a l r e s e a r c h is t h e t e s t

of a chemical l e a c h i r g p r o c e s s by Hudson Bay Mining and Smelting.

The

p r o c e s s o f f e r s both economic and p o l l u t i o n c o n t r o l b e n e f i t s , and h a s t h e p o t e n t i a l t o remove f r a n t h e environment o v er 70 k i l o t o n n e s o f 502 emissions annually.

.

I n v e s t i g a t i n g i n c r e a s e d use o f low-sulphur c o a l from Western Canada: federal-provincial

a

t a s k f o r c e w i l l s h o r t l y r e p o r t on t h e economic and

en v i r o n m en t a l impact o f i n c r e a s i n g t h e use o f low s u l p h u r Western Canadian c o a l i n On t a r io .

.

As s u r i n g $70 m i l l i o n f o r c l e a n e r , more e f f i c i e n t u s e of c o a l :

i n the past

year, Energy, Mines and R e s o u r c e s Canada h a s s p e n t ab o u t $50 m i l l i o n

r e s e a r c h i n g new, c l e a n e r methods o f b u r n i n g coal.

The r e s e a r c h p r o j e c t s

include:

-

e x p e n i m e n t s o n f l u i d i z e d bed c o m b u s t i o n , a p r o c e s s for b u r n i n g coal t h a t m i n i m i z e s t h e p r o d u c t i o n o f SO2 a n d NO,;

-

coal-water s l u r r y e x p e r i m e n t s , i n v o l v i n g t h e mixing of w a t e r w i t h c o a l b e f o r e i t is b u r n e d , t h e r e b y m i n i m i z i n g e m i s s i o n s ; and

-

tests o f a process c a l l e d limestone i n j e c t i o n multi-stage burning, whereby l i m e s t o n e , which is a l k a l i n e , is i n t r o d u c e d i n t o t h e c o m b u s t i o n chamber a n d n e u t r a l i z e s a c i d s r e l e a s e d d u r i n g c o a l c o m b u s t i o n and a l s o r e d u c e s NOx e m i s s i o n s . T h e s e e x p e r i m e n t s are b e i n g c o n d u c t e d a t Gagetown and Chatham, New

Brunswick; Victoria J u n c t i o n and P o i n t Tupper, Nova S c o t i a ; and Summerside a n d C h a r l o t t e t o w n , P r i n c e Edward I s l a n d .

It is e x p e c t e d t h a t t h e l e s s o n s

l e a r n e d f r a t h e s e p r o j e c t s w i l l h e l p i n d u s t r i e s across Canada meet t h e i r emission reduction t a r g e t s .

.

R e s e a r c h and m o n i t o r i n g

-

$30 m i l l i o n a y e a r w i t h $18 m i l l i o n o f t h i s

g u a r a n t e e d by t h e f e d e r a l government.

A priority i n the fight against

a c i d r a i n is t h e d e v e l o p m e n t o f a s y s t e m a t i c , c o - o r d i n a t e d e n v i r o n m e n t a l m o n i t o r i n g s y s t e m , which is c u r r e n t l y b e i n g worked on by f e d e r a l a n d p r o v i n c i a l s c i e n t i s t s and o t h e r o f f i c i a l s .

D a t a c o l l e c t e d by s u c h a

n e t w o r k , o v e r a p e r i o d o f years, is v i t a l b e c a u s e i t e n a b l e s s c i e n t i s t s t o d e t e r m i n e t h e s t a t u s of t h e e n v i r o n m e n t and i d e n t i f y c h a n g e s i n p o l l u t i o n levels.

Thus, s c i e n c e w i l l h e l p l e g i s l a t o r s d e t e r m i n e t h e e x t e n t o f t h e

b e n e f i c i a l e f f e c t of t h e c o n t r o l program. P u b l i c s u p p o r t f o r a c t i o n on a c i d r a i n c o n t i n u e s t o b e h i g h .

A majority

o f C a n a d i a n s s t a t e d i n a s u r v e y t h a t t h e y were w i l l i n g t o g i v e up a d a y ' s pay i n o r d e r t o f i g h t t h e scourge of a c i d r a i n . B u t e v e n w i t h t h e a m b i t i o u s program and t h e w i d e s u p p o r t from a l l s e c t o r s o f C a n a d i a n s o c i e t y , n o t a l l a r e a s o f Canada w i l l b e p r o t e c t e d . A p p r o x i m a t e l y 50% o f t h e s u l p h u r d i o x i d e i n t h e C a n a d i a n a t m o s p h e r e h a s its o r i g i n i n t h e U.S.A.

S o u t h e r n O n t a r i o is s u b j e c t m a i n l y t o t r a n s b o u n d a r y

i m p a c t s , a n d e v e n a 100% r e d u c t i o n i n C a n a d i a n SO2 e m i s s i o n s would n o t h e l p t h i s area.

303 I n t h e autumn o f 1985, t h e f e d e r a l and p r o v i n c i a l governments j o i n t l y sponsored a major i n t e r n a t i o n a l symposium on a c i d p r e c i p i t a t i o n , c a l l e d Over 600 s c i e n t i s t s from 1 8 n a t i o n s a t t e n d e d t h e week-long

"Muskoka ' 8 5 " . conference.

T h e i r f i n d i n g s reconfirmed t h a t a c i d r a i n is a s e r i o u s problem,

t h e s o l u t i o n s t o which a r e n o t o n l y p o s s i b l e b u t economically n e c e s s a r y .

The

f i n d i n g s r e v e a l e d a t Muskoka '85 o f f e r a f i r m b a s i s f o r p o l i t i c a l a c t i o n t o control acid rain. In March 1985 t h e P r i m e M i n i s t e r o f Canada and t h e P r e s i d e n t o f t h e United S t a t e s p e r s o n a l l y a p p o i n t e d S p e c i a l Envoys t o review and make recommendations on t h e b i l a t e r a l a c i d r a i n i s s u e . by t h e l e a d e r s i n March 1986.

T h e i r r e p o r t was endorsed

The r e p o r t s t a t e d t h a t a c i d r a i n from SO2 is a

s e r i o u s environmental and t r a n s b o u n d a r y problem, and made s e v e r a l recommendations on i n i t i a l s t e p s towards s o l v i n g t h e problem.

Canada w i l l

c o n t i n u e t o p r e s s f o r a program of 502 r e d u c t i o n s i n t h e U.S.

t o reduce t h e

transboundary flow i n t o Canada, s u f f i c i e n t t o meet t h e e s t a b l i s h e d environmental t a r g e t o f 20 kg/ha/yr

or less o f w e t s u l p h a t e d e p o s i t i o n .

Canada w i l l a l s o c o n t i n u e t o s t r o n g l y s u p p o r t t h e development o f f u r t h e r s p e c i f i c agreements and p r o t o c o l s t o reduce t h e widespread t h r e a t o f a c i d r a i n worldwide.

S c i e n t i s t s a r e c o n t i n u a l l y improving t h e i r u n d e r s t a n d i n g o f

t h e s o u r c e s , movement and i m p a c t s of t h e c m p o n e n t s o f a c i d d e p o s i t i o n . S c i e n c e h a s a l s o p o i n t e d t o t h e e m i s s i o n r e d u c t i o n s n e c e s s a r y t o meet t h e objectives.

This knowledge, combined with p o l i t i c a l w i l l on t h e p a r t o f

member c o u n t r i e s , w i l l h e l p t o g e n e r a t e t h e k i n d of i n t e r n a t i o n a l c o o p e r a t i o n needed t o p r o t e c t t h e g l o b a l environment.

T. Schneider (Editor)/Acidi7ication and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

385

SWEDISH POLICIES AND RESEARCH PROGRAMMES GURAN PERSSON The National Swedish Environment Protection Board, P 0 Box 1302, 171 25 Solna (Sweden)

Emission S t a t u s and Trends The Swedish emissions of s u l p h u r dioxide reached t h e i r peak value in the e a r l y 70s. Since then t h e emissions have decreased s u b s t a n t i a l l y and f u r t h e r reductions w i l l be implemented (Table 1.1). The aim of t h e Swedish government i s t o reduce sulphur emissions by a t l e a s t 65 % between t h e years 1980 and 1995. The energy s e c t o r accounts f o r about two t h i r d s of the t o t a l sulphur emissions. The development of t h e energy s e c t o r i s t h e r e f o r e of d e c i s i v e importance. In t h e Swedish s t r a t e g y t o combat a c i d i f i c a t i o n g r e a t a t t e n t i o n i s given t o t h e coordination of energy and environmental p o l i c i e s i n order t o minimize the e f f e c t of e l e c t r i c i t y and h e a t production on t h e environment. The c u r r e n t energy policy t a r g e t s imply t h a t t h e energy system should be based t o t h e g r e a t e s t possible e x t e n t on enduring, p r e f e r a b l e renewable and indigenous, energy sources. E f f i c i e n t energy use and s t r i n g e n t emission control requirements a r e encouraged. The reduction of t h e s u l p h u r content of fuel o i l - t h e only f o s s i l f u e l of importance in Sweden - has been c a r r i e d through according t o a plan adopted by t h e Parliament i n 1976. As from October 1 , 1984, t h e sulphur content of heavy f u e l o i l i s r e s t r i c t e d t o max 1 % n a t i o n a l l y . T h i s corresponds t o 0.24 g of sulphur per megajoule f u e l . The sulphur content of l i g h t f u e l o i l i s limited t o 0.3 % a s from October 1, 1980, and a new l i m i t in t h e range 0.15-0.28 i s planned. The reduction of t h e sulphur emissions from i n d u s t r i a l processes i s being achieved by t h e s t i p u l a t i o n of gradually more r i g i d emission standards in the permits granted under t h e Environmental Protection Act. The emission standard in t h e permits given f o r new coal-fired p l a n t s w i t h an annual t o t a l emission i n excess of 400 tonnes of sulphur, i s normally 0.1 g of s u l p h u r per megajoule f u e l .

306 The Swedish emissions o f n i t r o g e n oxides increased h e a v i l y d u r i n g t h e 50s and 60s.

The steep increase i n these decades f o l l o w s m a i n l y t h e expansion

o f t h e t o t a l number o f cars.

I n t h e 70s emissions increased o n l y s l i g h t l y and

s i n c e 1980 t h e y have decreased. Motor t r a f f i c accounts f o r about 70 % o f t o t a l n i t r o g e n oxides emissions. S t a t i o n a r y combustion sources c o n t r i b u t e w i t h about 20 % and i n d u s t r i a l p r o cesses w i t h about 10 % (Table 1 . 1 ) . The motor v e h i c l e exhaust standards from t h e 1976 year models e n t a i l e d a r e d u c t i o n o f n i t r o g e n oxides f r o m passenger c a r s by about 10 % between 1975 and 1980.

D u r i n g the same period, however, t h e emissions from d i e s e l v e h i c l e s

increased by t h e same amount. The aim o f t h e Swedish government i s t o reduce n i t r o g e n oxides emissions by

30 % between 1980 and 1985. t o those now i n e f f e c t i n t h e

Emission standards f o r passenger c a r s e q u i v a l e n t

U S have been i n t r o d u c e d on a v o l u n t a r y b a s i s

f o r the 1987 and 1988 c a r models and compulsory f o r t h e 1989 models.

To en-

courage t h e purchase o f "clean" v e h i c l e s t h e s a l e s t a x on t h e 1987 and 1988 c a r models c o n f i r m i n g t o t h e new standards i s reduced by SEK 5200.

To stimu-

l a t e t h e use o f l e a d - f r e e g a s o l i n e t h e t a x i s reduced by SEK 0.16 per l i t r e compared t o t h e premium grade c o n t a i n i n g 0.15 l e a d p e r l i t r e . F u r t h e r measures t o reduce emissions of n i t r o g e n oxides a r e being explored. These i n c l u d e new emission standards f o r d i e s e l v e h i c l e s and s t r i c t e r emission requirements on s t a t i o n a r y sources. The Swedish emissions o f non-methane hydrocarbons f o r 1980 and a prognosis f o r 1995 a r e g i v e n i n Table 1.1.

The estimates a r e c o n s i d e r a b l y more u n c e r t a i n

than f o r s u l p h u r d i o x i d e and n i t r o g e n oxides. Motor v e h i c l e s accounted f o r about 60 % o f t h e emissions o f hydrocarbons i n 1980. Emissions a r e expected t o decrease by about 30 % between 1980 and 1995.

A l l sources a r e p r o j e c t e d t o decrease t h e i r emissions.

The l a r g e s t decrease

i s expected from motor v e h i c l e s due t o t h e new emission standards f o r passenger cars. The Swedish emissions o f ammonia

a r e very u n c e r t a i n .

The annual emissions Manure i s t h e

from a g r i c u l t u r a l a c t i v i t i e s a r e estimated a t 40 000 tonnes. main source and steps a r e taken t o reduce emissions.

387

Effects

- and

I n Sweden about 18 000 lakes affected by a c i d i f i c a t i o n .

90 000 kilometres

o f running water are

The damages a r e most severe i n non-calcareous areas i n t h e western and southern p a r t of t h e country. Only a small corner i n the n o r t h i s n o t affected. The connection between d e p o s i t i o n of sulphur and a c i d i f i c a t i o n o f surface

water i s g e n e r a l l y accepted.

To avoid l a r g e scale a c i d i f i c a t i o n o f s e n s i t i v e

l a k e s and streams the d e p o s i t i o n o f sulphur should n o t exceed 0.5 g S/mP-y. The present l e v e l o f d e p o s i t i o n i n t h e western and southern p a r t o f the country i s 2 g S/mZ-y. New research r e s u l t s have shown a strong decades i n southern Sweden.

soil a c i d i f i c a t i o n

during the l a s t

The a c i d i f i c a t i o n has a severe impact on the s o i l

processes and leads t o increased l e a c h i n g o f magnesium and other e s s e n t i a l n u t r i e n t s and t o elevated l e v e l s o f aluminium and heavy metals i n ground and surface water. rep0 r t e d

.

Increased c o r r o s i o n on underground c o n s t r u c t i o n s have been

Acid groundwater

i s a problem i n many p a r t s o f Sweden.

To what extent the

a c i d i t y i s caused by a c i d d e p o s i t i o n i s n o t y e t q u i t e c l e a r . 400 000 permanent r e s i d e n t s and 650 000 r e c r e a t i o n houses a r e dependent on water supply from small p r i v a t e groundwater w e l l s .

The annual indoor damages due t o corrosion have been

estimated t o SEK 150 m i l l i o n s . The deposited n i t r o g e n c o n t r i b u t e s t o a c i d i f i c a t i o n o f surface and groundwater i f i t i s n o t consumed by vegetation.

During snow-melt n i t r i c a c i d may

c o n t r i b u t e t o t h e a c i d i f i c a t i o n o f running water by 20-30 per cent.

Such a c i d

surges w i t h extremely low pH-values a r e very detrimental t o f i s h - l i f e . Nitrogen has so f a r been a l i m i t i n g f a c t o r i n most t e r r e s t r i a l ecosystems and t h e d e p o s i t i o n o f n i t r o g e n has had a favourable e f f e c t on f o r e s t growth. There are, however,

i n d i c a t i o n s t h a t f o r e s t ecosystems i n southern Sweden are approaching a stage o f n i t r o g e n s a t u r a t i o n . This means t h a t primary production

w i l l n o t be f u r t h e r increased by increased n i t r o g e n supply.

Such systems may

leach considerable amounts o f n i t r a t e . The t a r g e t l e v e l s f o r d e p o s i t i o n t o avoid negative e f f e c t s o f n i t r o g e n s a t u r a t i o n o f f o r e s t s o i l have been estimated t o 1-2 g N/mz-y expressed as t o t a l d e p o s i t i o n o f o x i d i z e d and reduced n i t r o g e n compounds.

The present

d e p o s i t i o n i n southern Sweden exceeds 2‘ g N/m2-y. Nitrogen is t h e n u t r i e n t t h a t g e n e r a l l y l i m i t s growth i n the marine environI n t h e B a l t i c Sea t h e c o n t r i b u t i o n o f n i t r o g e n from atmospheric deposi-

ment.

t i o n amounts t o about one t h i r d o f t h e t o t a l load. B a l t i c Sea i s a m a t t e r o f g r e a t concern.

The e u t r o p h i c a t i o n o f the

I n t h e beginning of t h e 80s increased f o r e s t damages were reported a l s o i n Sweden.

Needle losses i n about 30 % o f o l d e r spruce stands i n t h e southern

and southwestern p a r t s o f the country a r e a t t r i b u t e d t o t h e combined e f f e c t s o f s o i l a c i d i f i c a t i o n , d i r e c t e f f e c t s o f a i r p o l l u t a n t s ( p a r t i c u l a r l y ozone) and extreme c l i m a t i c conditions. As a defense against a c i d i f i c a t i o n and t o r e s t o r e valuable lakes and streams a l i m i n g programme i s i n operation.

4 000 lakes have been t r e a t e d so f a r .

The money a v a i l a b l e from the Government f o r the year 1986/87 i s SEK 110 m i l l i o n s corresponding t o 85 per cent o f the t o t a l cost. The e f f e c t s o f l a k e i i m i n g are p o s i t i v e . Streams, however, are much more d i f f i c u l t t o handle as the waterf l o w v a r i e s by two orders o f magnitude and because t h e m e t a l - r i c h leachates from a c i d i f i e d s o i l s remain t o x i c even i f pH i s brought back t o normal values. The general experience i s t h a t countermeasures i n the environment are no acceptable s u b s t i t u t e s t o c o n t r o l measures a t t h e source. Important Issues i n Future Policy-Making The large-scale a c i d i f i c a t i o n and f o r e s t damages i n Europe today demonstrate t h a t t h e tolerance l i m i t s o f n a t u r e a r e exceeded.

Future i n t e r n a t i o n a l co-

operation w i t h i n t h e framework o f t h e Convention must provide answers t o t h e f o l l o w i n g questions:

-

What a r e t h e t a r g e t l e v e l s o f d e p o s i t i o n and a i r q u a l i t y t o safeguard a 1ong-term heal thy envi ronment?

-

What do these l e v e l s mean i n the form o f necessary emission reductions i n d i f f e r e n t areas?

-

What are the l e a s t - c o s t s o l u t i o n s t o achieve t h e emission reductions and how are they t o be implemented? I n most c o u n t r i e s n a t i o n a l energy and t r a n s p o r t a t i o n p o l i c i e s have been care o f t h e environment. I n t h e f u t u r e these

developed w i t h l i t t l e o r no

p o l i c i e s and t h e environmental p o l i c y w i l l have t o be c l o s e l y coordinated. P r i o r i t i e s i n Swedish A c i d i f i c a t i o n Research

_Depositign: --

Q u a n t i f i c a t i o n of d r y deposited n i t r o g e n substances, e s p e c i a l l y

o f gaseous n i t r i c acid, and i t s v a r i a t i o n w i t h topography, distance from f o r e s t edges, type o f vegetation,

etc.

389

-Forest - - -damages, ---

Effects

s o i l a c i d i f i c a t i o n i n combination w i t h extreme

Of

c l i m a t e c o n d i t i o n s (drought periods). D i r e c t e f f e c t s o f ozone and n i t r i c a c i d

-

studies i n open top chambers.

E f f e c t s o f n i t r o g e n s a t u r a t i o n on d i f f e r e n t p h y s i o l o g i c a l processes, e.g. f r o s t s e n s i t i v i t y and accumulation o f various organic substances, and on the f l o w of n i t r a t e and cations.

-Groundwater. -----

Development o f models o f groundwater a c i d i f i c a t i o n and chemistry

over t i m e as a f u n c t i o n of geology and l e v e l s o f deposition.

-Surface - - - _ - water.

Development o f models o f mercury content i n f i s h as a function

o f a c i d i f i c a t i o n and c h a r a c t e r i s t i c s o f t h e drainage area and the aquatic ecosystem.

Co~r~s~oE ~ f.f e- c t s

o f s o i l a c i d i f i c a t i o n on underground constructions.

-Countermeasures _ _ _ - _ - - - _ _i n_t -h e_ -environment, __

E f f e c t s o f l i m i n g o f surface water.

Development of methods t o r e s t o r e a c i d groundwater and t o n e u t r a l i z e f o r e s t s o i l and improve f o r e s t v i t a l i t y , I n t e r n a t i o n a l Research Evaluation Mechanisms A growing number o f c o u n t r i e s are e s t a b l i s h i n g a c i d i f i c a t i o n research and

m o n i t o r i n g programmes which means t h a t more and more data w i l l be a v a i l a b l e . Results from i n d i v i d u a l research p r o j e c t s and short-term monitoring programmes are o f t e n o f l i m i t e d value i n t h e process o f d e c i s i o n making. c r i t i c a l questions are formulated,

However, i f the

data from d i f f e r e n t c o u n t r i e s can be

assessed and e i t h e r provide the answers o r i d e n t i f y the important gaps f o r f u r t h e r research and monitoring. I t i s e s s e n t i a l t h a t i n each n a t i o n a l a c i d i f i c a t i o n research and monitoring

programme resources are a l l o c a t e d f o r assessment o f e x i s t i n g data outside t h e own programme.

W i t h i n t h e Convention such assessments could be made by small

groups o f c o u n t r i e s and the r e s u l t s discussed by experts from a l l i n t e r e s t e d parties. Evaluation o f research

r e s u l t s r e l e v a n t t o the problem discussed w i t h i n t h e

Convention should be an important p a r t o f the work p l a n o f the Executive Body.

W ID

0

TABLE 1.1 Emission trends in Sweden (1000 tonnes) 1980 NO,

1984

CH

1990

CH

s02

NO,

1995

CH

CH

SO2

Stationary combustion sources

252

67

4

106

46

89

53

80

52

3

Industrial noncombustion sources

150

34

70

98

19

70

19

50

19

55

Non-i ndus trial and domestic activities

63

28

95

40

19

18

13

14

12

85

Mobile sources

18

199

258

20

205

16

181

12

157

152

Total

483

328

427

264

289

193

266

156

240

2 95

Index

100

100

100

32

73

69

SO2

SO2

NO,

Source

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

391

UNITED STATES POLICY ON A C I D R A I N R i c h a r d E l l i o t Benedick Deputy A s s i s t a n t S e c r e t a r y f o r Environment, H e a l t h and N a t u r a l Resources, Department o f S t a t e , Washington, D.C. (U.S.A.)

ABSTRACT A c i d r a i n has proven i n t h e U n i t e d S t a t e s t o be a d i v i s i v e domestic p o l i t i c a l i s s u e , a s e r i o u s concern w i t h o u r n o r t h e r n n e i g h b o r Canada, and a complex e c o l o g i c a l problem w i t h c o n s i d e r a b l e s c i e n t i f i c u n c e r t a i n t y . The U.S. has developed o v e r t h e l a s t 15 y e a r s an a g r e s s i v e program t o p r o t e c t p u b l i c h e a l t h f r o m e m i s s i o n s o f SO2, NOx and v o l a t i l e o r g a n i c compounds (VOC's). Through a c o m b i n a t i o n o f ambient s t a n d a r d s and s t r i c t r e g u l a t i o n o f new s t a t i o n a r y and m o b i l e sources, we have succeeded i n h a l t i n g t h e r a p i d g r o w t h o f S02. T h i s was accomplished d e s p i t e s i g n i f i c a n t growth i n t h e U.S. economy and i n c o a l consumption. A f t e r t h o r o u g h r e v i e w , t h e U.S. has concluded t h a t , a l t h o u g h a c i d r a i n i s a s e r i o u s concern, t h e r e i s s i g n i f i c a n t u n c e r t a i n t y c o n c e r n i n g t h e e x t e n t and magnitude o f b o t h c u r r e n t and p o t e n t i a l f u t u r e a c i d r a i n damage. However, t h e U.S. Government does n o t p l a n t o w a i t f o r d e f i n i t i v e answers on a l l a c i d r a i n q u e s t i o n s , and i s f u l l y committed t o f i n d i n g a p p r o p r i a t e s o l u t i o n s t o t h e problem o f a c i d r a i n as e x p e d i t i o u s l y as p o s s i b l e . Thus, w h i l e t h e U n i t e d S t a t e s i s d e f e r r i n g any d e c i s i o n on new mandatory cont r o l s f o r a c i d r a i n , we a r e moving ahead v i g o r o u s l y w i t h s e v e r a l n o t e w o r t h y p r o grams. F i r s t , e x i s t i n g l e g a l a u t h o r i t y i s b e i n g used t o expand c o n t r o l o v e r e m i s s i o n s o f SO2, NOx, and VOC's. Second, an a m b i t i o u s t e n - y e a r r e s e a r c h p r o gram i s a d d r e s s i n g t h e s c i e n t i f i c u n c e r t a i n t i e s . T h i r d , t h e development and d e m o n s t r a t i o n o f i n n o v a t i v e c o n t r o l t e c h n o l o g y i s b e i n g s t r o n g l y promoted, which s h o u l d b r i n g some n e a r - t e r m e m i s s i o n s r e d u c t i o n s . And f o u r t h , a new c h a p t e r i n c o o p e r a t i o n w i t h o u r Canadian n e i g h b o r s has been opened t h r o u g h P r e s i d e n t Reagan's f u l l endorsement o f t h e r e c e n t r e p o r t o f t h e U.S. and Canadian S p e c i a l Envoys. INTRODUCTION A c i d r a i n has proven i n t h e U n i t e d S t a t e s t o be a d i v i s i v e domestic p o l i t i c a l i s s u e , a s e r i o u s concern w i t h o u r n o r t h e r n n e i g h b o r Canada, and a complex ecoloqi c a l problem w i t h c o n s i d e r a b l e s c i e n t i f i c u n c e r t a i n t y .

A l l o f these f a c t o r s

have c o n t r i b u t e d t o t h e e v o l u t i o n o f U.S. p o l i c y on a c i d r a i n . PAST ACTIONS AND PROGRESS The U n i t e d S t a t e s e n a c t e d m a j o r l e g i s l a t i o n t o p r o t e c t a i r q u a l i t y o v e r 15 y e a r s ago.

The Clean A i r A c t o f 1970, t o g e t h e r w i t h m a j o r amendments added i n

1977, r e s u l t e d i n an a i r p o l l u t i o n c o n t r o l e f f o r t t h a t has s e r v e d as a model f o r many o t h e r i n d u s t r i a l i z e d n a t i o n s . They have a l s o l e d t o s i g n i f i c a n t , measurab l e improvements i n a i r q u a l i t y i n t h e U n i t e d S t a t e s .

392 P r o b a b l y t h e s i n g l e most i m p o r t a n t f e a t u r e o f t h e Clean A i r A c t i s t h e establ i s h m e n t o f N a t i o n a l Ambient A i r Q u a l i t y Standards (NAAQS) f o r a i r p o l l u t a n t s . These s t a n d a r d s r e q u i r e t h a t ambient c o n c e n t r a t i o n s o f t h o s e p o l l u t a n t s be NAAQS f o r s u l f u r

l i m i t e d t o l e v e l s t h a t s a f e g u a r d p u b l i c h e a l t h and w e l f a r e .

d i o x i d e ( S O Z ) , n i t r o g e n o x i d e s (NOx), and v o l a t i l e o r g a n i c compounds (VOC’s), a l l o f which c o n t r i b u t e t o a c i d r a i n , have been i n e f f e c t f o r o v e r t e n y e a r s . W i t h i n t h e United States, i t i s t h e i n d i v i d u a l States which are responsible f o r e n s u r i n g t h a t t h e NAAQS a r e met w i t h i n t h e i r own b o r d e r s .

I n order t o

a t t a i n t h e Federal s t a n d a r d s l o c a l l y , t h e S t a t e s s e t emissions l i m i t s on e x i s t ing facilities. The Clean A i r A c t a l s o s e t s e m i s s i o n s l i m i t s f o r v a r i o u s c l a s s e s o f s t a t i o n a r y sources.

The t h e o r y b e h i n d t h i s was t h a t emissions from new sources

c o u l d be c o n t r o l l e d a t much l o w e r c o s t t h a n e m i s s i o n s f r o m e x i s t i n g sources, and t h a t t h e r e q u i r e m e n t t o c o n t r o l new sources would encourage t h e development o f more e f f i c i e n t and c o s t - e f f e c t i v e c o n t r o l t e c h n o l o g i e s .

Furthermore, t h e

c o n t r o l o f new sources c o u l d l e a d t o c l e a n e r a i r as o l d f a c i l i t i e s were eventua l l y replaced.

To d a t e , t h e U n i t e d S t a t e s has s e t New Source Performance Stand-

a r d s t o c o n t r o l e m i s s i o n s o f SO2 a n d l o r NOx f r o m a l l new o i l - and c o a l - f i r e d power p l a n t s , l a r g e i n d u s t r i a l b o i l e r s , s m e l t e r s , n i t r i c a c i d p l a n t s , s u l f u r i c a c i d p l a n t s , s t a t i o n a r y gas t u r b i n e s , and p e t r o l e u m r e f i n e r i e s .

Standards f o r

V O C ’ s have a l s o been s e t f o r s e v e r a l new source c a t e g o r i e s .

Besides c o n t r o l l i n g s e v e r a l k i n d s o f s t a t i o n a r y sources, t h e Clean A i r A c t a l s o l i m i t s a i r e m i s s i o n s f r o m new m o b i l e sources.

Standards t o l i m i t NOx and

VOC’s f r o m new c a r s and l i g h t - d u t y t r u c k s were f i r s t implemented i n 1973, and t h e y have been t i g h t e n e d s i n c e then. These Federal and S t a t e a c t i o n s have u n d o u b t e d l y h e l p e d t o improve a i r q u a l i t y i n t h e United States s t r o n g growth o f U.S.

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a remarkab’le accomplishment c o n s i d e r i n g t h e

i n d u s t r i a l production i n recent years.

A t t h i s time,

about 98 p e r c e n t o f c o u n t i e s i n t h e U n i t e d S t a t e s a r e i n compliance w i t h t h e n a t i o n a l s t a n d a r d s f o r SO2 and NOx.

S u l f u r d i o x i d e e m i s s i o n s f e l l f r o m a peak

o f 28 m i l l i o n m e t r i c t o n s i n 1972 t o a b o u t 2 1 m i l l i o n m e t r i c t o n s i n 1984, d e s p i t e a 35 p e r c e n t g r o w t h i n c o a l use.

V o l a t i l e o r g a n i c compounds f o l l o w e d a

s i m i l a r path, w h i l e a p r e c i p i t o u s r i s e i n NOx emissions was h a l t e d and t u r n e d t o a l e v e l trend. D e s p i t e t h i s p r o g r e s s , t h e r e i s some cause f o r concern.

Approximately four

p e r c e n t o f l a k e s r e c e n t l y surveyed i n t h e n o r t h e a s t e r n U n i t e d S t a t e s were found t o be a c i d i c . levels.

There i s e v i d e n c e o f reduced c r o p g r o w t h f r o m ambient ozone

A l t h o u g h u n e x p l a i n e d v i s i b l e damage t o h i g h a l t i t u d e s p r u c e - f i r t r e e s

amounts t o a f r a c t i o n o f one p e r c e n t o f t h e e a s t e r n U.S. f o r e s t area, we a r e n e v e r t h e l e s s concerned about p o s s i b l e f u t u r e t r e n d s . Growth r a t e changes have been r e c o r d e d f o r s e v e r a l o t h e r t r e e s p e c i e s w h i c h may be l i n k e d t o atmospheric

393 pollution.

I t i s a l s o b e l i e v e d t h a t b u i l d i n g s and m a t e r i a l s i n some areas a r e

experiencing accelerated d e t e r i o r a t i o n . FUTURE UNCERTAINTIES AND POLICY CONSIDERATIONS L o o k i n g t o t h e f u t u r e , NOx e m i s s i o n s a r e p r o j e c t e d t o i n c r e a s e s l i g h t l y by

1995, d e s p i t e t h e c o n t i n u i n g t u r n o v e r o f t h e n a t i o n a l v e h i c l e f l e e t and t h e p r o g r e s s i v e l y more s t r i n g e n t c o n t r o l s p l a c e d on a u t o m o b i l e and t r u c k emissions. S u l f u r d i o x i d e emissions a r e much more d i f f i c u l t t o p r o j e c t , because economic growth, e x i s t i n g r e g u l a t o r y programs, changing f u e l use p a t t e r n s , and t h e p o w e r p l a n t s a l l w i l l a f f e c t emissions i n d i f f e r e n t and

extended l i f e o f U.S. u n c e r t a i n ways.

We a r e c u r r e n t l y unsure whether t h e y w i l l i n c r e a s e o r decrease

o v e r t h e n e x t decade. A g a i n s t t h i s background, e v o l v i n g U.S. primary questions.

a c i d r a i n p o l i c y must address t h r e e

F i r s t , t o what e x t e n t must emissions o f a c i d r a i n p r e c u r s o r s

be reduced i n o r d e r t o a d e q u a t e l y p r o t e c t t h e r e s o u r c e s a t r i s k i n N o r t h Second, where s h o u l d e m i s s i o n s r e d u c t i o n s t a k e p l a c e ? And t h i r d , when

America?

s h o u l d t h o s e r e d u c t i o n s be made? programs s h o u l d reduce emissions.

Over t h e l o n g e r term, e x i s t i n g r e g u l a t o r y But w i l l t h i s r e d u c t i o n be adequate and w i l l

o u r l a k e s and f o r e s t s be t h r e a t e n e d i n t h e meantime?

Do we need t o embark on a

m a j o r program o f r e t r o f i t c o n t r o l s on e x i s t i n g s o u r c e s ?

I f so, i n what p a r t s o f

t h e c o u n t r y s h o u l d sources be r e t r o f i t t e d ? I n t h e U n i t e d S t a t e s , a c i d r a i n has been as p o l i t i c a l l y d i v i s i v e as any e n v i r o n m e n t a l i s s u e t h e c o u n t r y has faced.

V a r i o u s proposed s o l u t i o n s have

opposed one r e g i o n a g a i n s t a n o t h e r ; t h e y have t h r e a t e n e d t h e l i v e l i h o o d o f h i g h s u l f u r c o a l m i n e r s , and have r a i s e d t h e p o s s i b i 1 it y o f s i g n i f i c a n t i n c r e a s e s i n e l e c t r i c i t y r a t e s i n p r e c i s e l y t h o s e i n d u s t r i a l a r e a s h a r d e s t h i t by economic d i s locations. The a c i d r a i n i s s u e has been e s p e c i a l l y d i f f i c u l t t o r e s o l v e because proposed s o l u t i o n s must choose f r o m a l i m i t e d a r r a y o f o p t i o n s .

Most SO2 emissions i n

t h e U n i t e d S t a t e s a r e f r o m e l e c t r i c u t i l i t y and i n d u s t r i a l b o i l e r s .

A t this

t i m e , o n l y t h r e e e m i s s i o n s c o n t r o l t e c h n i q u e s a r e proven and a v a i l a b l e f o r r e d u c i n g SO2 e m i s s i o n s f r o m c o a l - f i r e d b o i l e r s : flue-gas-scrubbing.

coal-washing,

c o a l - s w i t c h i n g , and

However, c o a l - w a s h i n g cannot be used t o a c h i e v e s u b s t a n t i a l

SO2 r e d u c t i o n s , and t h e o t h e r two methods impose h i g h socioeconomic c o s t s on p a r t i c u l a r regions

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f o r example, unemployment o r h i g h e r e l e c t r i c i t y r a t e s .

The a v a i l a b i l i t y o f a b r o a d e r range o f e f f i c i e n t and c o s t - e f f e c t i v e c o n t r o l t e c h n o l o g i e s c o u l d h e l p t o r e d u c e t h e s e p o l i t i c a l and economic d i f f i c u l t i e s .

A f u r t h e r complication i s t h e u n a v a i l a b i l i t y o f a s o l i d basis t o determine t h e e x t e n t and magnitude o f c u r r e n t o r p o t e n t i a l f u t u r e a c i d r a i n damage.

NO

one can say w i t h c o n f i d e n c e what l e v e l o f e n v i r o n m e n t a l b e n e f i t s would r e s u l t f r o m any s p e c i f i c c o n t r o l proqram.

We a r e l i m i t e d i n o u r a b i l i t y t o p r e d i c t how

394 much a c i d d e p o s i t i o n would be reduced i n any p a r t i c u l a r geographic area by any g i v e n c o n t r o l program.

A l t h o u g h t h e c o s t s o f c o n t r o l , and t h e p e o p l e who would

pay t h o s e c o s t s , a r e r a t h e r w e l l understood, t h e e x t e n t o f e n v i r o n m e n t a l improvement t h a t would r e s u l t remains h i g h l y u n c e r t a i n .

I n such a s i t u a t i o n , p o l i t i c a l

consensus i s d i f f i c u l t t o achieve. RECENT DEVELOPMENTS I n 1983, t h e U.S.

Government c a r r i e d o u t a t h o r o u g h r e v i e w o f t h e s t a t e o f

a c i d r a i n knowledge and t h e o p t i o n s a v a i l a b l e f o r i t s management.

Following

t h a t r e v i e w , i t was concluded t h a t , a l t h o u g h a c i d r a i n was c l e a r l y a s e r i o u s concern, t h e r e was i n s u f f i c i e n t i n f o r m a t i o n t o embark upon a new emissions cont r o l program.

T h i s was n o t a d e c i s i o n e i t h e r f o r o r a g a i n s t f u r t h e r c o n t r o l s ,

b u t r a t h e r t o d e f e r such a d e c i s i o n u n t i l a more adequate s c i e n t i f i c and t e c h n i c a l base was e s t a b l i s h e d . I n t h e meantime, i t s h o u l d be r e c o g n i z e d t h a t t h e U n i t e d S t a t e s has t a k e n n o t a b l e s t e p s i n r e c e n t y e a r s t o address t h e a c i d r a i n problem.

First, i t i s

u s i n g e x i s t i n g l e g a l a u t h o r i t y t o expand c o n t r o l o v e r e m i s s i o n s o f a c i d r a i n precursors.

Second, an a m b i t i o u s r e s e a r c h program i s a d d r e s s i n g t h e s c i e n t i f i c T h i r d , t h e development and d e m o n s t r a t i o n o f i n n o v a t i v e c o n t r o l

uncertainties.

t e c h n o l o g y i s b e i n g s t r o n g l y promoted.

And f o u r t h , a new c h a p t e r i n c o o p e r a t i o n

w i t h o u r Canadian n e i g h b o r s has been opened. New R e g u l a t i o n s The U n i t e d S t a t e s r e c e n t l y implemented new r e g u l a t i o n s t o c o n t r o l f u t u r e e m i s s i o n s o f SO2, NOx and VOC's.

I n March 1985, new s t a n d a r d s were e s t a b l i s h e d

f o r c o n t r o l l i n g e m i s s i o n s o f p a r t i c u l a t e s and NOx f r o m l i g h t - d u t y and heavyd u t y t r u c k s , as w e l l as f r o m u r b a n buses.

A f t e r becoming e f f e c t i v e w i t h t h e

1988 model y e a r , t h e s e s t a n d a r d s a r e e x p e c t e d t o reduce NOx emissions by about two m i l l i o n m e t r i c t o n s p e r y e a r . R e g u l a t i o n s were a l s o r e c e n t l y passed l i m i t i n g t h e amount o f p o l l u t i o n cont r o l c r e d i t t h a t can be c l a i m e d b y a p l a n t t h a t b u i l d s a t a l l smokestack.

Tall

s t a c k s h e l p such p l a n t s a c h i e v e ambient a i r q u a l i t y s t a n d a r d s l o c a l l y by d i s p e r s i n g e m i s s i o n s o v e r b r o a d e r areas, b u t t h e y do n o t reduce t h e t o t a l amount of SO2 e m i t t e d .

By e l i m i n a t i n g t h i s i n c e n t i v e t o b u i l d t a l l smokestacks, t h e U.S.

Government aims t o encourage p o l l u t i o n c o n t r o l s t h a t w i l l a c t u a l l y l i m i t t o t a l emissions. O t h e r r e g u l a t i o n s a r e b e i n g developed t h a t s h o u l d f u r t h e r reduce f u t u r e SO2 and NOx emissions, i n c l u d i n g s t a n d a r d s t o c o n t r o l emissions from new i n d u s t r i a l b o i l e r s , w h i c h s h o u l d be i n e f f e c t

b y t h e end o f t h e decade.

395 Expanded Research I n addition t o regulatory actions, the

U.S. Government has funded a t e n - y e a r

r e s e a r c h program t a r g e t t e d s p e c i f i c a l l y a t causes and e f f e c t s o f a c i d r a i n t h e N a t i o n a l A c i d P r e c i p i t a t i o n Assessment Program (NAPAP).

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Since 1982,

s t e a d i l y r i s i n g annual budgets have t o t a l l e d $225 m i l l i o n , p l u s an a d d i t i o n a l $85 m i l l i o n i n t h e coming f i s c a l y e a r .

Research funds a r e d i v i d e d among p r o -

j e c t s s t u d y i n g a t m o s p h e r i c processes, t e r r e s t r i a l e f f e c t s , d e p o s i t i o n m o n i t o r i n g , and a q u a t i c e f f e c t s . Among o t h e r t h i n g s , t h e 1985 program funded p r o j e c t s t h a t :

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i n c r e a s e d t h e q u a l i t y o f man-made emissions i n v e n t o r i e s . a c c e l e r a t e d t h e development o f atmospheric models. f u l l y implemented t h e n a t i o n w i d e wet d e p o s i t i o n m o n i t o r i n g network. commenced d r y d e p o s i t i o n m o n i t o r i n g . completed t h e f i r s t phase o f a N a t i o n a l S u r f a c e Water Survey. conducted s o i l s u r v e y s o f r e p r e s e n t a t i v e watersheds. developed m e t h o d o l o g i e s f o r a n a t i o n a l s u r v e y o f f o r e s t e f f e c t s . analyzed c o n t r o l technologies.

I n n o v a t i v e Technology The movement o f a c i d i c substances and o x i d a n t s across t h e U.S.-Canadian b o r d e r i s r e c e i v i n g p a r t i c u l a r a t t e n t i o n by b o t h governments.

I n March 1985,

P r e s i d e n t Reagan and Canadian Prime M i n i s t e r Mulroney a p p o i n t e d two d i s t i n g u i s h ed S p e c i a l Envoys, Drew Lewis o f t h e U n i t e d S t a t e s and B i l l Davis o f Canada, t o s t u d y t h e t r a n s b o u n d a r y a c i d r a i n i s s u e and r e p o r t back w i t h recommendations on ways t o r e s o l v e i t . The S p e c i a l Envoys p r e s e n t e d t h e i r r e p o r t i n January, 1986. o f t h e i r recommendations f o r t h e U n i t e d S t a t e s i s a f i v e - y e a r ,

A m a j o r element five billion

d o l l a r c o n t r o l t e c h n o l o g y commercial d e m o n s t r a t i o n program, co-funded by t h e Federal government and p r i v a t e i n d u s t r y .

By d e m o n s t r a t i n g

i n existing plants

t h e commercial f e a s i b i l i t y o f i n n o v a t i v e c o n t r o l t e c h n o l o g i e s t h a t promise l o w e r c o s t s a n d / o r g r e a t e r e f f i c i e n c i e s , t h i s program c o u l d expand t h e l i s t o f cont r o l o p t i o n s a v a i l a b l e t o U.S.

i n d u s t r y , f a c i l i t a t e a domestic consensus on

a c i d r a i n , and a c h i e v e some n e a r - t e r m r e d u c t i o n s i n t r a n s b o u n d a r y f l o w s . The U.S.

Government has s t a t e d t h a t i t w i l l seek t o p r o v i d e t h e f u t u r e fund-

i n g recommended by t h e S p e c i a l Envoys.

I n t h i s c o n n e c t i o n , I would n o t e t h a t

t h e U n i t e d S t a t e s has a l r e a d y expended $2.2 b i l l i o n i n r e s e a r c h funds between f i s c a l y e a r s 1981 and 1985 t o d e v e l o p t e c h n o l o g i e s f o r c l e a n e r use o f c o a l .

In

t h i s y e a r ' s budget, $700 m i l l i o n i s earmarked f o r c l e a n c o a l r e s e a r c h up t o

1991.

I n a d d i t i o n , an $800 m i l l i o n j o i n t i n d u s t r y l g o v e r n m e n t program t o demon-

s t r a t e new c l e a n ways t o use c o a l i s b e i n g implemented. C o o p e r a t i o n w i t h Canada The Envoys a l s o recommended t h a t t h e two governments p u t i n p l a c e mechanisms

t o encourage c o o p e r a t i o n on t h i s i s s u e .

E x i s t i n g l e g i s l a t i o n i n both countries

w i l l be r e v i e w e d t o i d e n t i f y o p p o r t u n i t i e s t o c o n t r o l t r a n s b o u n d a r y a i r p o l l u t i o n ; a c i d r a i n w i l l r e m a i n h i g h on t h e agenda o f meetings between t h e P r e s i d e n t and t h e Prime M i n i s t e r ; and t h e two governments w i l l e s t a b l i s h a b i l a t e r a l a d v i s o r y and c o n s u l t a t i v e group on t r a n s b o u n d a r y a i r p o l l u t i o n . The S p e c i a l Envoys a l s o recommended enhanced c o o p e r a t i v e r e s e a r c h e f f o r t s t o s t u d y d r y d e p o s i t i o n m o n i t o r i n g , r a t e s o f a q u a t i c change, impacts on a q u a t i c b i o l o g y , f o r e s t s , and m a t e r i a l s , and p o t e n t i a

damage f r o m heavy m e t a l s .

CONCLUSION L e t me c o n c l u d e by o b s e r v i n g t h a t t h e Pres d e n t o f t h e U n i t e d S t a t e s t h i s y e a r f u l l y endorsed t h e r e p o r t o f t h e S p e c i a l Envoys, and p l a n n i n g i s now underway t o implement a l l o f i t s recommendations.

As t h e Report s t r e s s e d , i n o r d e r

f o r p r o g r e s s on a c i d r a i n t o be p o s s i b l e , t h e recommendations must be r e a l i s t i c : " t h e y must n o t ask e i t h e r c o u n t r y t o make a sudden, r e v o l u t i o n a r y change i n i t s p o s i t i o n " o r " c a l l f o r immediate abandonment o f m a j o r p o l i c y stands."

I s h o u l d emphasize h e r e t h a t i t i s not U.S. p o l i c y t o w a i t f o r d e f i n i t i v e answers on a l l a c i d r a i n u n c e r t a i n t i e s b e f o r e a c t i n g .

D e c i s i o n s on a c i d r a i n ,

l i k e o t h e r e n v i r o n m e n t a l d e c i s i o n s , w i l l always have t o o c c u r i n t h e f a c e o f some s c i e n t i f i c u n c e r t a i n t y .

The U n i t e d S t a t e s w i l l a c t when i t i s r e a s o n a b l y

c e r t a i n t h a t such a c t i o n w i l l a c h i e v e i t s i n t e n d e d r e s u l t s , and t h a t t h o s e r e s u l t s w i l l j u s t i f y t h e s o c i a l and economic c o s t s i n v o l v e d . Thus, w h i l e t h e U n i t e d S t a t e s has d e f e r r e d new mandatory c o n t r o l s f o r a c i d r a i n , we a r e moving ahead v i g o r o u s l y w i t h t h e programs o u t l i n e d above.

The

U n i t e d S t a t e s Government i s f u l l y committed t o f i n d i n g a p p r o p r i a t e s o l u t i o n s t o t h e problem o f a c i d r a i n as e x p e d i t i o u s l y as p o s s i b l e .

397

T. Schneider (Editor)/Acidificationand its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

SITUATION, STRATEGIE ET POLITIQUE SUR LA POLLUTION ATMOSPHERIQUE TRANSFRONTIERE A GRANDES DISTANCES EN ESPAGNE M i n i s t e r e de Travaux P u b l i c s e t d'urbanisme D i r e c t i o n Generale de 1 'Environnement N o t r e pays c o n s i d e r e que l a p o l l u t i o n atmospherique e t l e s acides

ne

c o n s t i t u e n t de problemes

l e s a u t r e s pays. Nous c o n s i d e r o n s

dbpositions

a u s s i g r a v e e t g e n C r a l i s e s que dans

come

prioritaire

la

conservation

de

l ' e n v i r o n n e m e n t e t l a p r o t e c t i o n de r e s o u r c e s n a t u r e l l e s , s u r t o u t des v a s t e zones de l a M e d i t e r r a n e e q u i s o n t a t t a c h e s p a r l a sechresse, pris

une

serie

b l a b o r e s des s t r a t e g i e s resumees dans

la

desertisation.

les

suivants

control

des

Nous

avons

g l o b a l e SO

emission

l'aridite

et

de mesures e t nous avons

. planification y

2'

points:

reduction

y

pol i t i q u e energetique;

l ' u t i l i s a t i o n des charbons avec un t a u x bas de s o u f r e ; e m p l i de gaz n a t u r e 1 dans

les

centrales

thermiques;

A

technoliques aplicables directives

communautaire

suspension

et

Surveillance

le

elaboratorion

l a combustion

de

de

nos

plans

charbons;

s u r l a q u a l i t 6 de l ' a i r (SO

plomb);

nouvelles

stations

de

de

recherches

adaptation

de

NO p a r t i c u l e s en 2' 2' l ' a c t u e l Reseau de

EMEP, en i n c o r p o r a n t l e s mesures de gaz de NO , HNO e t a i n s i x 3 etc. etc.

que de p a r t i c u l e s NO

3'

C e t t e t a c h e e s t d i f i c i l e e t couteuse, l a q u e l l e empgche, pour l ' i n s t a n t , 1 'etablissement

d'une

strategie

politique

plus

dure

pour

reduire

la

p o l l u t i o n atmospherique.

-

Le Gouvernement Espagnol e s t chaque j o u r p l u s c o n s c i e n t de

la

pollution

atmospherique

et

de

l'importance

c o n s i d e r e t o u j o u r s l a Convention de

Geneve comme l e m e i l l e u r c a d r e i n t e r n a t i o n a l pour c o m b a t t r e l a transfrontiere

et

etudier

les

effets

des

dkpositions

pollution acides

sur

1 ' e n v i ronnement.

- Nous

considerons

meteorologiques

que, et

gr6ce

geologiques,

d

nos

la

pollution

conditions

atmospherique

d b p o s i t i o n s a c i d e s ne c o n s t i t u e n t en Espagne de problemes et

gknCralisbs

que

dans

les

(evapotranspiration, i n s o l a t i o n

geographiques, et

les

a u s s i graves

a u t r e s pays. N o t r e c l i m a t o l o g i e s p e c i a l e &levee,

hautes

temperatures

et

basse

398

pluvimetrie)

et

la

f a i b l e c o n c e n t r a t i o n de c e n t r e s p o l l u t a n t s par km

provoquent q u ' i l y a i t p l u t d t des d e p o s i t i o n s seches de

-

nitrates

et

2

de

s u l f a t e s en forme d ' a e r o s o l s que des p l u i t s acides proprement d i t e s . Notre pays considere c o m e p r i o r i t a i r e l a c o n s e r v a t i o n de 1 'environnement e t l a p r o t e c t i o n des ressources n a t u r e l l e s . Par conequant, e l reclamme un p l u s grand i n t e r e t pour l e s problemes a d d i t i o n n e l s de l'aridite,

de

de

qui

front

que

nos

ecosystemes

soient

plus

s e n s i b l e s e t p l u s v u l n e r a b l e s aux agents p o l l u a n t s . D ' a u t r e p a r t , on d e d u i t des montre

dernieres

etudes

realisees

que

1'Espagne

un p e t i t s o l d e r e c e p t e u r p o s i t i f en ce q u i concerne l e s emissions

SO

e t de poussiere 2 d'Europe e t d ' A f r i q u e .

de

-

sbchresse,

d e g r a d a t i o n des sols e t de l a d e s e r t i s a t i o n de vastes

la

zones de l a MCditerranee

-

la

en

suspension

provenantes,

respectivement,

Nous avons d e t e c t 4 l ' e x i s t a n c e des degats des messes f o r e s t i e r e s culture

des

des p r o v i n c e s de C a s t e l l o n , de Teruel e t de Tarragona, a i n s i que

de n o t r e p a t r i m o i n e a r t i s t i q u e e t c u l t u r e 1

- A l a l u m i e r e des t r a v a u x e t des n'est

et

pas

etudes

.

realises

jusqu'd,

present,

il

p o s s i b l e d ' b t a b l i r un d i a g n o s t i q u e f i n a l de l ' e x i s t a n c e d'une

r e l a t i o n c a u s e - e f f e t de d e p o s i t i o n humide dans l e s d e g l t s observes.

-

dangers

NCanmoins, nous sommes c o n s c i e n t s des r i s q u e e t des cette

situation

qu'entraine

pour l ' a v e n i r en pour c e l a nous avons p r i s une s e r i e de

mesures en nous avons b l a b o r e s des s t r a t e g i e s qui peuvent

6tre

r4sumCes

dans l e s s u i v e n t p o i n t s :

-A

p a r t i r de 1985, l e s emissions

ete

i n d u s t r i a l i s e s ont

-

En 1983, d l a s u i t e Convention

-

de

de

GenCve

de SO dans 2 r e d u i t e s d'un 50%. l'entre sur

en

la

vigeur

Pollution

les dans

ensembles notre

urbains

pays

Transfrontieres,

de ont

la

ete

commences, l a p l a n i f i c a t i o n e t l e p r o j e t du Reseau National EMEP. En 1984, l a premiere de ces s t a t i o n s a Pablo

commence

A

functioner

A

San

de 10s Montes (Toledo) e t aussi l a S t a t i o n Basse de l a P o l l u t i o n

de "Fond" de Izana,

A T e n e r i f e , aus i l e s Canaries,

du

Reseau

BaPMoN,

patronne pa l e PNUMA e t coordinne par l a OMM.

-

En accord avec l e s p r e v i s i o n s a c t u e l l e s de l a et

l e s hypothese

raisonnables

de

energetique

l a consommation, on peut considerer

qu'en 1992, l e s emissions t o t a l e s de SO 1980.

planification

2

seront de l a m6me gradeur

qu'en

399

- Cela s i g n i f i q u e

une importante r e d u c t i o n des

-

principalement

de

celles

emissions

e n t r e p r i s de mesures tendantes d l e s r e d u i r e s , vu estime

-

que

actuelles

-

et

q u i e x i s t e r a i e n t en 1992 s i on n ' a v a i t pas qu'd

cette

date,

on

l ' a u g m e n t a t i o n de l a consommation de l ' e n e r g i e p r i m a i r e sera

de 27%. Etant

donne

qu'importe,

que

la

plupart

sera

de

basse

du

charbon

teneur

en

additionnel

national

r e i s o n n a b l e de r e u s s i r des r e d u c t i o n s suplementaires de SO

- Des mesures de p o l i t i q u e Cnergetique q u i emissions

globales,

naturel , l a reduction

ainsi

soufre, il y a des p o s s i b i l i t e s comprennent

une

2' reduction

des

par example: l a promotion de l a consommation de gaz

reduction

de

draconienne

la

capacite

des

heures

installee de

son

fuel-oil,

une

functionnement,

due

la

d i v e r s i f i c a t i o n de l a s t r u c t u r e de l a p r o d u c t i o n e l e c t r i q u e pour 1992, l e develloppement

-

d'une

puissance

hydralique,

la

stimulation

de

la

s u s t i t u t i o n des p r o d u i t s p e t r o l i f e r e s e t du develloppement renovelables. Promotion de l a r e d u c t i o n l'antracite

du

soufre

contenu

dans

l'houille

et

dans

n a t i o n a l e d e s t i n e s aux thermiques e t dans l e s l i g n i t e s n o i r s

pour 1 'usage e l e c t r i q u e .

- L ' u t i l i s a t i o n des

charbons avec un t a u x bas de s o u f r e pour

les

melanges

avec l e s l i g n i t e s d'une grande t e n e u r en soufre.

- Combustion

de gaz n a t u r e l dans l e s c e n t r a l e s s i t u e e s dans

es

zones

S,

A

de

grande d e n s i t e de population.

- Amelioration

de l a teneur des combustibles

l'obligation

-

de

solides

utilis

traver

t o u t e s l e s grandes e n t r e p r i s e s de p r o d u c t i o n e l e c t r i q u e

d ' a v o i r des l a b o r a t o i r e s d'analyse de l e u r s charbons. A m e l i o r a t i o n du c o n t r d l e des niveaux d'emissions e t d'immissions dans l e s c e n t r a l e s thermiques conventionnelles, d t r a v e r s de l ' e x t e n s i o n d t o u t l e parc de puissance fuel-oil,

-

superieure d 50 MW pour l e charbon e t 200 MW pour

1'obligation

de

le

disposer d'equipements de mesure c o n t i n u e l l e

NO e t de p a r t i c u l e s ; e t ameliorer e t completer l e s 2' x reseaux de s u r v e i l l a n c e d'immission de ces composes.

des emissions de SO

- Developpement, Economique

en c o l a b o r a t i o n avec l e s a u t r e s

Europeenne, de plans de recherches

pays

de

la

Commission

echnol ogi ques appl i c a b l es

d l a combustion de nos charbons.

- Entree en v i g e u r par

laquelle

on

de l a normative, a j u s t e e d l a Ctabli

directive

communautaire,

de n o u v e l l e s normes de q u a l i t e de 1 ' a i r e t on

400

d h f i n i t l e s valeurs reference

-

limites,

declaration

les de

valeurs la

guides

et

les

valeurs

de

s i t u a t i o n d ' e x c e p t i o n du d i o x i d e de

s o u f r e e t des p a r t i c u l e s en suspension. De meme, l a n o r m a t i v e q u i d e f i n i t l e s v a l e u r s d'azote,

-

pour

et

le

plomb

et

les

valeurs

limites

pour

le

dioxide

guides pour l e d i o x i d e d'azote

e x i s t a n t s dans l ' a t m o s p h e r e , e s t s u r l e p o i n t d ' e n t r e r en v i g e u r . Pour c e q u i r e s t e de l ' a n n e e 1986, on espere a g r a n d i r l ' a c u t e l Reseau Surveillance

de

EMEP/BaPMoN de t r o i s n o u v e l l e s s t a t i o n s ( c e que f e r a q u a t r e

au t o t a l ) en i n c o r p o r a n t l e s mesures de gaz de NO , HNO e t NH a i n s i que x 3 3

-

de p a r t i c u l e s NO avec

-

3

-.

Pendant l e s annees 1987 les

quatre

-

1989 on c o m p l e t e r a l e p r o j e t du Reseau N a t i o n a l

stations

restantes

q u i s ' a d o p t e r o n t au programme des

mesures du EMEP p o u r c e t t e phase. Toutes ces a c t i v i t e s v o n t i m p l i q u e r p o u r n o t r e pays l a r e d u c t i o n e t en

oeuvre

de

nouveaux

plans

et

t r a v e r s des programmes de c o n t r 6 l e e t de d i m i n u t i o n des e m i s s i o n s

-

mise

d ' a m 4 I i o r a t i o n de l a q u a l i t e de l ' a i r , d la

mise d p o i n t de t o u s l e s resseaux de s u r v e i l l a n c e e x i s t a n t s . deposition

On augmentera l e s e t u d e s s u r l a d i f f u s i o n , l e t r a n s p o r t e t l a des

polluants

dans

1 'atmosphere,

ainsi

programmes c o n c e r t e s d ' e v o l u t i o n de t r a n s p o r t

que

l e developpement

d

grandes

distances

de des

p o l l u a n t s atmosphkriques en Europe.

- Cette tache empGche,

nous o b l i g e d une a d a p t i o n d i f f i c i l e

pour

et

couteuse,

laquelle

l ' i n s t a n t , l'etablissement d'une s t r a t e g i e p o l i t i q u e plus

d u r e r e d u i r e l a p o l l u t i o n atmospherique.

- Neanmoins, sommes pour

nous c r o y o n s que nous f a i s o n s un

en t r a i n lutter

grand

effort

et

que

nous

de c r k e r l ' i n f r a s t r u c t u r e e t l e s s t r a t e g i e s n e c e s s a i r e s

contre

la

pollution

atmosphbrique

et

1 ' a c i d i f i c a t i o n , en pensant des m a i n t e n a n t d 1 ' a n 2000.

les

effets

de

401

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

Acidification and its policy implications: Statement by Ireland

Ireland's situation as regards acidification differs from the mainstream European experience in a number of ways.

Our peripheral location and prevailing

westerly winds spare us from any significant transboundary air pollution.

Our total emissions

of SO2 are low, constituting only 1% of overall EEC emissions, so that EEC guide values are almost invariably observed and minimal contribution is made to sulphur deposition in other countries.

Much

of the research interest in Ireland's situation relates indeed to the "zero effect" baseline conditions that exist

over much of our country.

But Ireland's position is also distinguished by a relatively high population growth, a need to industrialise further and an energy system lacking connection with the European grid and enjoying only limited resources of indigenous natural gas. These factors make it difficult for Ireland to undertake further reductionof its already low national emissions of SOz,

although in recent years

we have in fact achieved reductions on the 1980 level well in excess of the 30% envisaged by the Helsinki Protocol.

402

-

Despite Ireland's lack of direct experience of acidification, public and political interest in the issue has developed greatly in recent years. A number of studies and proposals on acid rain have been made by interested environmental groups and a parliamentary committee has recently reported on the subject.

-

Irish SO2 emissions are low both in absolute terms and in relation to 1 9 8 0 . SO2 emissions were 2 1 7 , 0 0 0

In that year, estimated tonnes.

By 1 9 8 4 ,

emissions had decreased by 4 3 % to 1 2 3 , 0 0 0 tonnes and this included a 55% reduction in emissions from power plants.

This environmentally favourable trend

resulted from a conscious energy policy of replacing imported oil with coal and indigenous natural gas. In 1 9 7 9 , nearly 60% of electricity was produced from oil and only 7.4% from gas.

In 1 9 8 4 , natural

gas accounted for over 4 7 % of fuel inputs to electricity generation, with oil contributing just 1 9 % .

-

At present, electricity generation is consuming about two thirds of Irish natural gas production. Government policy for the further use of this limited natural resource is to channel it primarily towards the premium market of direct consumption in the domestic, industrial and service sectors.

Important

403

environmental as well as economic reasons support this policy.

Ireland's most serious air pollution

problem is with smoke levels in Dublin, which have had to be notified to the EEC as likely to exceed the limit values of Directive 8 0 / 7 7 9 . Increased use of natural gas in Dublin, particularly in the domestic sector, is desirable to abate this problem.

It follows that the supply of natural gas for power generation cannot be guaranteed as the exceptional level which has obtained in recent years.

Nuclear

power is not at present a viable option for Ireland,

so that reliance on imported fossil fuels is set gradually to increase again.

The Government

have, however, directed a study to be carried out

of the possible costs involved in reducing future emissions from power plants to the extent necessary to achieve a stabilisation of overall national sulphur emissions at the 1980 level.

The study is

under way.

-

A number of recurring provisions in the international

conventions and resolutions relevant to this Conference well reflect Ireland's position.

Both

the Munich Conference Resolution and Annex I1 to the Helsinki Protocol note the situation of countries whose emissions are small and whose

404

contribution to transboundary fluxes is insignificant. The Geneva Convention itself envisages control measures compatible with balanced development.

-

Up to now, statutory control of atmospheric emissions in Ireland has relied principally on control of individual plants through the physical planning system and on a very limited system of inspecting so-called alkali works.

A new Bill has, however,

been published this year which will provide a comprehensive framework for control of air pollution in the years ahead, and in particular support the implementation of relevant EEC Directives.

-

Although much of the Bill will be implemented through our local government system, it also contains important powers which will allow the Minister for the Environment to establish a national regime of control.

The Minister will be able to

prescribe air quality standards and emission limit values and to direct local authorities and other implementing agencies on a wide range of matters. For their part, local authorities will be enabled to adopt air quality management plans.

-

An important purpose of the new Bill is to establish a licensing system for new industrial plants as required by the relevant EC Directive.

In fact,

405

our system will exceed EEC requirements in certain respects and generally provide full powers for local authorities to protect air quality from new industrial emissions.

Sampling and analysis of rainfall has been carried out regularly by our Meteorological Service for many years.

While the network and procedures

were not specifically optimised for assessing acid rain, the considerable volume of pH data accumulated has indicated a tendency towards increased acidity, despite considerable variations in rainfall acidity levels.

The causes are not

entirely clear.

Since 1980, Ireland has participated in the EMEP Programme, with a monitoring station in Valentia, Co. Kerry in south west Ireland operating the

minimum measurement plan for sampling and analysis. We hope to extend the range of data from the present year and also to add a monitoring station in the Irish midlands to the EMEP Programme.

Research on acidification in Ireland is mainly being conducted in collaboration with EEC and other international programmes.

Work is at present in

progress on rain chemistry in the Dublin region, on lakes, on damage to buildings and on forests.

406

All of these studies have still to be fully completed.

-

The research project on rain chemistry involves extensive and specific rainfall analyses which are being carried out at a range of stations in the Dublin region.

This region was chosen because

it could be expected to pick up any deposition from large Irish emitters to the west or southwest, such as power stations, as well as depositions from transboundary sources.

-

The preliminary findings of the study, covering 1983 and 1984, suggest some presence of

transboundary air pollution.

The highest deposition

rates for sulphate and nitrate, derived from

SO2

and NOX respectively, can be correlated clearly with a NE

-

SE wind direction.

Low pH levels

in rainfall are also associated much more frequently with this wind direction.

It must be emphasised,

however, that these findings are not definitive and require corroboration by more widely based research.

-

There has not so far been any evidence in Ireland of damage to lakes or forests from acid rain. However, the results of the two relevant research projects are awaited with interest.

407

In' summary, Ireland's direct experience of acidification has been slight; in conformity with the Geneva Convention we will maintain our low levels of air emissions within the constraints of development; and we will continue to offer full co-operation on research into thismost important problem.

T.Schneider (Editor)/Acidificationand its Policy Implications Elsevier Science PublishersB.V., Amsterdam - Printed in The Netherlands

409

THE NETHERLANDS POLICY AND RESEARCH PROGRAMME ON ACIDIFICATION

S.

Zwerver and

P.J. Verkerk

INTRODUCTION The main features of the acidification control policy were developed in the Indicative Multi-year Programme on Air Pollution 1985-1989 which was sent to Parliament by the Minister of Housing, Physical Planning and Environment in September 1984. Acidification was broadly interpreted in that programme. The influence of photochemical air pollution was also understood as acidification if it involved damage to forests and vegetation. The policy has been further elaborated in the subsequent Environmental Programe's of the Netherlands (1985-1989

and 1986-1990).

Situation Although 90

SO2

control also took place before 1984, it has not prevented

percent of the Netherlands' fens from being damaged in the meantime. Injury

to the Netherlands' forests could also be shown after the alarm was rung in Central Europe concerning forests. An inventory by our Forestry commission shows that 50 percent of our POLICY

forests are now less vital,

Inventory of forest damage

such an extent that, although

13

percent have been damaged to

the possibility of recovery has 1984

1985

not been excluded, it must be

Healthy

51%

50%

assumed that a great deal will

Slightly damaged

40%

35%

have to be replaced in the me-

Damaged

8%

13%

dium term, and 2 percent of our

Dead or dying

1%

2%

forests have been irrevocably lost and will have to be cut

FIGURE 1

down in the short term.

The soil is sensitive to acidification in large parts of the Netherlands. It is precisely in these areas that, due to historical and social-economic reasons, large scale intensive livestock raising is carried out. Because of the

410 Areas in the Netherlands with soils sensitive to acidification.

intensive livestock raising industry, we in the Netherlands have both the problem of surplus manure and the problem of acidification from ammonia. It also means that the soil in the Netherlands is burdened not only by deposition of SO2 and NOx

- as is the case everywhere in - but also by NH3, produced chief-

Europe

ly in our own country. All in all, our estimate is that the input in our soil of acidifying substances originating in our country and elsewhere is too high by a factor of two to FIGURE 2

sours :STIBOKA ern

four.

Damage We estimate the damage from acidification and the effects of photochemical air pollution at an annual amount of US $ 250-350 million. This does not include effects which cannot

- or can hardly - be

expressed in monetary terms,

such as the disappearance of plant and animal species, damage to our cultural property, and the often irreversible effects on soil. In the absence of control measures, the annual damage will increase to circa US 5 350-600 million. As shown in the table (Figure 3), a significant share of the current damage is caused by the reduced harvest yield. The largest part of this reduced yield is due to ozone; a smaller share results from SO2 and fluorine. This was calculated by two of our large agricultural institutes, namely the Institute for Plant Disease Research and the Agricultural Economics Institute. In the future, but also evident already, the financial consequences of forest damage will become increasingly more important.

- 655

Current damage Future damage Agriculture Nature management Forestry &creation Cultural goods Users goods Drinking and industrial water recovery

565

5

55 40

WAL

700

-

30

-

100

-

800

Pm Pm Pm

565 15 170

- 655 - 55 - 550 Pm - 100

55 40 20 50 900 -1500

-

411

Origin O n average in the Netherlands, the total deposition of substances

contributing to soil acidification amounts to circa 6000 mol Hf per hectare per year (Figure 4 ) . This deposition is composed of:

-

and sulfates originating in our own country and far over our borders (Figure 5 ) ,

SO2

NO, and nitrates that are deposited o n the soil over large areas less pointedly than SO2 (Figure 6 ) , and finally N H 3 and ammonium that are created primarily as a result of the livestock industry in our own country (Figure 7).

FIGURE 6

FIGURE 7

412

We have recently learned that ammonia does not have to be an exclusively Dutch problem. A recent inventory of the NH3 emission pattern in Europe by an institute of our university in Utrecht gives cause to believe that NH3 could also play a role elsewhere. It is, therefore, possibly also important for other countries to combat ammonia in certain regions. AVERAGE DEPOSITION AND ORIGIN OF POTENTIALLY ACIDIFYING SUBSTANCES (ACID EQUIVALENT/HECTARE/A"UM) IN THE NETHERLANDS. I

I

Deposition from natural sources (rough estimate) Deposition from Dutch sources

SO2

NO,

NH3

280

130

190

570

430

1350

Deposition from foreign sources

1900

750

400

Total deposition in the Netherlands

2750

1310

1940

FIGURE 8

All in all, the composition of deposition in the Netherlands is approximately as indicated in the table (Figure 8 ) . The level of circa 6000 mol H+ per hectare per year is higher than we think acceptable by a factor of two to four. The table in Figure 9 shows that, with the exception of NH3, the largest share of the deposition orcginates in nearby countries.

I

I

ORIGIN OF SO,, NO,, NH, DEPOSITION IN THE NETHERLANDS (IN PERCENT) ) Country

'1 :il 23

Nearby countries: FRG U.K. Belgium France GDR other countries Total

33

I 12

25

16

71

7 4

61

!I26

6

6

3

100

100

100

1) Estimate based on model calculations. FIGURE 9

ACIDIFICATION POLICY AND RESEARCH IN THE NETHERLANDS

-

Policy

-General --The kernel of the Netherlands' acidification policy is determined by two factors. In the first place, there is the fact that we have first established a provisional objective for the deposition of acidifying substances. The

413 technological and economic possibilities have been weighed in establishing the tempo with which it will be attempted to achieve the objective, namely the year 2000, and to a certain extent in the stringency of the objective itself. Based on this deposition objective, a package of control measures has been drawn up and a time path has been set out for the phased introduction of the measures. The second factor is the role of research. We did not think it responsible to wait with measures until all research was exhausted. Therefore, the measures have already been set out. Research does have an important function in the supervision of the effectiveness and efficiency of the control measures. Government and industry

- who must

implement the measures

-

cooperate in the research. Together government and industry have drawn up a research programme that, added to research already being done in this field, primarily functions as a check on the effectiveness of the policy. Thus, should the research show, f o r example, that the role of nitrogen compounds is greater than is currently assumed, it could happen that the emphasis of the policy will shift to NO, and NH3 control. This research programme, financed and steered jointly by government and industry, runs for three years. It is expected that the research will deliver results in 1988 that will play a r o l e in the planned evaluation of the deposition objective and the associated measures. A central place has been made in the research for "integral monitoring" of forests. This has been made central because knowledge about the mechanism of damage from acidification is crucial for instituting or, if necessary, adapting measures.

.Provisional . . . . . .objective . . . . . for . . acidifying . . . . . . substances . . . . Based on current knowledge about the causes and effects of acidification, a provisional objective for the deposition of acidifying substances has been drawn up which could prevent the most serious effects of acidification. This deposition objective is based on data from abroad Canada

- and from our

-

especially Sweden and

own country. This objective for deposition is 1400 equi-

valents acid per hectare per year, which is intended to protect vital vegetation. Less vital vegetation and very sensitive surface waters are not, however, protected by this. In the past it was assumed that the ecosystem of a vital forest can absorb 1600

equivalents N per hectare per year without contributing to soil acidifi-

cation. Recent research has shown that this threshold value of 1600 equivalents N per hectare per year only applies for the short term; with prolonged exposure, the ecosystem will become saturated and the deposition will have an acidifying effect.

414

At the April workshop on "Critical loads for Sulphur and Nitrogen" held in O s l o at the initiative of the Nordic Council of Ministers, the consensus of

expert opinion was that in the l o n g term deposition will have to be reduced considerably more than the objective currently adhered to by the Netherlands.

.Emission . . . . .reduction . . . . . .of.acidifying . . . . . . .substances .. If this deposition objective were applied to all of Europe, it would mean a 70 percent reduction in SO2 emissions and a 30 percent reduction in NO, emissions in Europe compared to the level in 1980. Acid deposition in the Netherlands exceeds the average in Europe. This is so because NH3 emissions are much larger in the Netherlands (by approximately a factor of three) than on average in Europe. In order to attain the provisional objective in the Netherlands, N H ~emissions in the Netherlands must also be reduced by 50 percent. The problem, of course, is to achieve a balanced approach, in which a reasonably distributed effort is realized for the different sources and substances that contribute to acidification. Such a package of measures has been drawn up for the Netherlands. The package of measures that was drawn up will lead to the attainment of emission reductions of circa 60 percent for S02,

circa 30 percent for NO, and circa 50 percent for NH3 in the year 2000

compared to 1980 in the Netherlands. The measures for SO2 amount to flue gas desulphurization, fluidized bed combustion and use of low sulfur fuels at coal and oil fired combustion installations, reduction of process emissions in industry and at refineries, and reduction of the allowed sulphur content of diesel fuel and bunker oil. The measures for NO, are directed partly at mobile sources, for which strict standards will apply that can only be achieved through use of three way POLICY

Abatement measures SO2

- Flue gas desulphurisation - process emissions

-

%

S in fuel oil

- stricter standards for motor vehicles - Low-NO, combustion for stationary sources NH3 - limiting amount of manure spread per ha NO,

- manure injection into the soil

FIGURE 10

415

catalytic converters or lean-burn motors, and partly at stationary sources, where low

REDUCl!ION OF EllISSIONS I N 2000 (-ON

NO,

KG/-)

combustion systems for furnaces and

process integrated control technologies for industrial sources will be obligatory. The (intensive) livestock raising industry is Agriculture

the chief NH3 source that will be con-

Power plants

trolled, particularly through the introduc-

Refineries

tion of norms for the quantity of manure

Traffic

I

that may be spread per hectare and through

70

promotion of more favourable kinds of

Others

stalls. We will also promote the spreading of manure in a way that generates less

70

TOTAL

ammonia (manure injection, rapid plowing under, etc.). This leads to a considerable

FIGURE 1 1

emission reduction (Figure 1 1 ) .

The measures are being carried out partly via the legislative instrument of general administratjve ordera (e.g. furnaces) and partly via instruments such as public information (e.g. NH3 from agriculture) and economic incentives

(e.g. traffic). Large costs accompany the programme (Figure 121.

~

-~

Yearly costs in the year 2000 million guilderdannum 0 ,

,200 1"" + +

10"

40"

+

50"

+

00" i

I

I""

,

ROO

QUO

8

+

10""

m n q " l m u % *I

II

416

Development - - - - - -of_emissions ---We are trying to realize in the Netherlands the contribution to the reduction that we can deliver ourselves. The graph (Figure 13) presents how emissions in the Netherlands will progress if this policy is successful.

Expected emissions of SO,, NO. and NH, as a result of planned abatement in the mlllo""~,.nn"m Netherlands

t

600

/

,! .i .!.i ii

i f i

:

.1.

.

c.

FIGURE 13

Whether or not the deposition objective is achieved also depends on agreement in the framework of the convention on Long Range Transboundary Air Pollution and particularly on the efforts of nearby countries. The Netherlands is aware that they cannot solve the acidification problem alone. The scenario to be followed internationally determines whether we will reach our goal. As shown in the figure (Figure 14, next page), only one of the many conceivable options is sufficient to reduce current deposition to the level of 1400 mol H+ per hectare per year.

In our opinion, only reducing So2 emissions by 30 percent, as was agreed to

in the Helsinki PKOtOCOl, is not sufficient. More steps with respect to S O 2 will have to be taken. A reduction in the order of magnitude of 70 percent is necessary in our view.

417

ACID DEPOSITION IN THE NFlPagRLANDS AT DIFFERENT INTERNATIONAL POLICY OPTIONS

I

I I

current situation I I

1

I I

I

Helsinki protocol (30% reduction of S 0 2 )

70% reduction of in the +-' Netherlands and its nearby countries I

SO2 I

I 30% reduction of

SO2

30% reduction of NOx

1'

+

Netherlands abatement policy for S 0 2 , NOx and NH3 exclusively in the Netherlands J

I I 1

I I

Netherlands abatemeht policy exclusively in the Netherlands I

Netherlands abatement +policy also in the nearby countries I

I

1

I

I

highest acceptable

F I G U R E 14

But no matter how seriously SO2 is dealt with, a problem will remain if NOx emissions are not also dealt with. The second cluster of options shows how important additional NO, reduction

-

for example, by circa 30 percent

-

is for

the Netherlands. We must take into account that no matter how energetically policy is developed nationally or internationally, more effects of acidification are going to appear during the coming decades. The measures currently planned are

insufficient to prevent that. Moreover, there are effects for which the seed has already been planted and which are now unavoidable. In that connection it is essential to devote timely attention to temporary management measures on the effects side. Possibly in this way can the dying off of forests be temporarily delayed. Research

_-_

General

In 1983 Parliament requested information from the government about the effects of acid deposition and how government would tackle acidification. In response to this, a brief but very thorough survey was held that same year on the effects on soil, groundwater, vegetation, surface waters and animals living in the soil or water. Both the effects that were observed and those that might be anticipated were investigated. The Ministers of Environment and Agriculture presented their findings to Parliament in January 1984. It contained, among other things, the main outline of the research that was regarded as necessary. At Parliament's request the report on the problem of acidification of 8

January 1984, was followed by a report which dealt specifically with the

organization of acidification research. The latter, submitted on 21 June 1984, was debated in Parliament on 13 February 1985. The report contains a rough survey of current research, priorities set with regard to the content of future research and the organizational structure of research.

_Research _ _ _ _already _ _ _ _underway ___-

Research into different aspects of the acidification problem has been going

on for many years in the Netherlands. Much of this research takes place as part of air pollution research: the main topics are emissions, abatement technologies, atmospheric processes, transport and dispersion models, wet and dry deposition research and monitoring of air concentrations. Partly in another context, research into effects has also been underway for many years: changes in the natural environment (terrestrial and aquatic) and the effects of air pollution on crops, natural vegetation, forests and heathland, materials and cultural goods. The quality of forests and groundwater have also been monitored for several years now. For some time, too, damage to plants from oxidants ( 0 3 and NO21 and at prevailing oxidant levels has been the subject of investigation. In the past such research involved mainly fumigation tests in which the plants were exposed to much higher concentrations.

419

Moreover, as part of the joint German-Dutch project (PHOXA), photochemical air pollution in Western Europe is a subject of study. A model is being used in an attempt to gain insight into the relationship between European emissions of nitrogen oxides and hydrocarbons on the one hand and high ozone concentrations on the other. The research budget in 1985 was approximately 70 million guilders (circa US $ 25 million). It contained 2 1 5 projects and was carried out by about 30 institutes (Figure 1 2 ) . The research is commissioned mainly by the Ministries of Housing, Physical Planning and Environment, of Agriculture and Fisheries and of Economic Affairs (Figure 1 3 ) . But it may also be commissioned by provincial and municipal authorities and industry.

Approach --In the report to Parliament concerning the organization of research was consciously decided not to re-organize or give central guidance to research already underway. Instead we determined to set up a supplementary research programme. We were satisfied with the results of research already underway. Re-organizati.on would be detrimental to scarce research capacity rather than providing an increase in yield. It was considered efficient to charge a small group of directly interested parties (government and industry) with designing the supplementary programme. Under the direction of a steering committee in which government and industry (Co-operative Electricity Producers and refineries) co-operate and whose members provide joint financing (circa 15 million), this supplementary programme has been drawn up for three years. The starting point of the programme is to guard that the policy already implemented and the measures associated with it are in fact an effective and efficient answer to acidification, or in other words, to guard that the optimal yield is being attained.

.Main . . features . . . . .of. the . . supplementary . . . . . . . .research . . . . programme . . . . General The additional programme of research was drawn up from the assumption that the major blindspots in the acidification problem should be remedied first. The main ones in the Netherlands were:

-

the relationship between exposure and effect (particularly for forests and

-

abatement technology for ammonia

-

crops) effectiveness of the package of measures (system model)

These three themes have been incorporated into the programme with heavy emphasis on the first, of which "integrated monitoring" is an essential part. A programme was drawn up consisting of separate projects for the priority research themes. The programme has been running since 1 January 1985. 21 institutes are participating. All of the institutes receive a contribution from the supplementary acidification research budget, but also provide partial financing themselves. Relationship between exposure and effect

For the Netherlands

- which

has big problems with manure production in the

intensive livestock and poultry raising industry

-

the NH3 emitted by manure

is a research priority. Further, we want to institute cost-effective measures which is why system analysis via the development of an integral acidification model is another priority. Among the research priorities, however, the theme 'relationship between exposure and effect' springs to the fore. This theme is being approached from several angles, namely field and laboratory research into trees and natural vegetation, inventories and crop research.

- a thriving one and a less - where integral measurements will be carried out over a three

The field research concerns two Douglas stands thriving one

year period. The objective is to investigate the effect of air pollution and deposition on the physiological processes of trees in the field. The processes being researched are photosynthesis, respiration and water management. The field experiments are being supported by laboratory research, which concerns:

-

soil processes mineral intake growth study with varying loads of air pollution and different soils effects of fungi on growth effects of changes in soils on root fungi effect of PH on the take up of ions in the root zone. Inventorying research will be carried out on a limited scale into the

relationships among air pollution, soil parameters and the viability of forests by way of a first step to extrapolating the research results from the two previous parts. This study will link up with the viability research in Dutch forests which has already been underway for two years.

42 1

It emerged form earlier research that, in addition to HF, SO2 and 0 3 cause considerable damage to crops in the Netherlands (on the order of 600 million guilders per year or about 5% of the revenue). It is thought that each of these substances enhances the effects of the other. The research is moving from detailed study of processes in and on parts of plants (leaf curves) via separate plants (assimilation chambers) and groups of plants (fumigation chambers and open-top-chambers) to crops in field conditions and entire stands of vegetation (field fumigation systems). Photosynthesis and respiration are being examined as well as growth rate, leaf weight and nutrient intake as a function of the exposure to air pollution by substances separately (SOz, 0 3 and NH3) or in combination. The research is being backed by model studies so that an explanatory model can be developed. EXPECTATIONS FOR ACIDIFICATION RESEARCH AND POLICY Research One year after the start of the supplementary research programme, a pronounced role in water and soil acidification is already being assigned to N. Based on current data, it can be expected that the threshold value of 1600 equivalents H+ for N

- as part of the provisional deposition objective

for acidifying substances

shown to be untenable. Depending on the

- will be

kind of soil o r water to be protected and for what period, deposition limits are being named which are on the order of magnitude of 5-20 kg N/ha-l yr-l. These values are in line with the results of the O s l o workshop concerning deposition guide values for sulphur and nitrogen compounds. It is expected that the PHOXA results will present a clearer picture of ozone formation on a European scale. This can possibly provide inducement for diverting the emphasis of acidification research somewhat to nitrogenoxides and hydrocarbons. In any case, it is expected that Nox's central place in the research will be strengthened. Policy If the expectations of the research have a positive result, this will mean that pressure for the control of nitrogenoxides and hydrocarbons will become even greater. On 1 April 1986, fiscal measures entered into force that should stimulate the use of unleaded petrol and the sale of clean automobiles. Based

on presently foreseen measures for mobile sources, anthropogenic emissions will decrease by 27 percent in 2000 (Figure 15).

422

1 1

Policy

-.i-'

Developmentof hydrocarbon emissions in The Netherlands (abatement at mobile and stationary sources as planned) Emissions

,:;

6ooj

ca 500 in 1976

.....

341 in 2000

200

FIGURE 15 The wish to control NO, emissions further could mean that pressure will be created to go further than the application of low-NOx combustion systems for stationary sources. It is possible that an adjustment in the provisional deposition objective will have to be decided upon in 1988. This has been requested in a parliamentary motion. CONCLUSIONS AND RECOMMENDATIONS The Netherlands has formulated a provisional deposition objective which is intended to protect vital vegetation against the effects of acidification. In order to reach the level of the objective, SO2 and NO, w i l l have to be reduced to a significant extent on an international scale. Moreover, NH3 emissions will have to be controlled in the Netherlands itself. The Netherlands has drawn up a package of measures to achieve the goal of a circa 70 percent reduction in S02, 30 percent in NO,,

and 50 percent in NH3

emissions around the year 2 0 0 0 . The Netherlands considers the SO2 protocol providing for a 30 percent SO2 reduction in 1993 a positive first step, but not a conclusive one. The Netherlands believes that it is essential to also realize a substantial reduction in NO,. achieving this.

Mobile and Stationary sources require separate approaches in

423

In view of the large scale character of photochemical air pollution and the extensive damage to vegetation, among other things, caused by ozone, it is also important to include hydrocarbons in the control of air pollution on a European scale. The Netherlands considers it essential that conferences such as this one in support of international control of acidification take place regularly example once every two or three years

- in the framework of the ECE.

- for

425

T. Schneider (Editor)/Acidification and its Policy Implications ElsevierSciencePublishers B.V., Amsterdam - Printed in The Netherlands

PRESENTATION BY THE DELEGATION OF NORWAY

I n a presentation

of

Norway's

national

policies

in

the

field

of

a c i d i f i c a t i o n two b a s i c c o n s i d e r a t i o n s should be p o i n t e d out. F i r s t : 90% o f a c i d i c d e p o s i t i o n s i n Norway come from abroad.

Thus, t h e

problem o f a c i d i f i c a t i o n has a genuine transboundary c h a r a c t e r and can o n l y be s o l v e d t h r o u g h c l o s e i n t e r n a t i o n a l major

thrust

on

our

efforts

is

cooperation. directed

at

This

implies

searching

that

a

international

agreements f o r t h e r e d u c t i o n o f harmful substances t o t h e atmosphere. Second: i n t h e f i e l d o f nature

that

one

cannot

environment,

full

await

b e f o r e t h e necessary a c t i o n i s taken. character.

certain

problems

are

of

such

s c i e n t i f i c c e r t a i n t y on a l l aspects Acid r a i n

is

a

problem

of

this

To o u r minds, t h e evidence i n t h i s case has l o n g been more than

s u f f i c i e n t t o warrant prompt a c t i o n .

Effective technical solutions are

at

hand. We can see no v a l i d excuse f o r any i n d u s t r i a l i z e d n a t i o n t o r e f u s e t o t a k e e f f e c t i v e steps t o reduce t h e i r emissions. This i s . o f course, n o t say

that

we

do

not

need

to

know

more

to

about t h e e f f e c t s , causes and

mechanisms i n v o l v e d i n a c i d r a i n .

I should l i k e t o s t a r t my r e v i e w by saying some words about monitoring. NATIONAL MONITORING I n 1980 a major m o n i t o r i n g program was e s t a b l i s h e d i n o r d e r t o e v a l u a t e the

status

as

well

as

a c i d i f i c a t i o n and damages

trends to

i n p r e c i p i t a t i o n q u a l i t y , water and s o i l

fish

and

invertebrates.

This

monitoring

program i n c l u d e s d a i l y sampling f o r r e g i s t r a t i o n o f p r e c i p i t a t i o n chemistry a t 9 s t a t i o n s , d a i l y measurements o f s u l p h u r d i o x i d e and s u l p h a t e i n a i r a t

6

stations,

and

NO

2

measurements

a t 3 s t a t i o n s . There a r e a l s o monthly

water sampling i n 16-20 r i v e r s i n southern and western Norway, weekly water sampling

at

4

c a l i b r a t e d catchments and monthly sampling i n ground water

reservoirs.

I n c l u d e d i n t h e m o n i t o r i n g programme i s a l s o r e g i s t r a t i o n o f f i s h

stocks

lakes

in

and

rivers

as

well

as

sampling

o f the invertebrate

communities. Our e f f o r t s so f a r have been concentrated m a i n l y on

the

southern

and

426

western

part

of

the

country.

However, t h e r e i s c l e a r evidence t h a t t h e

e f f e c t s of a c i d i f i c a t i o n a r e growing a t an alarming r a t e i n t h e western and eastern

parts

o f t h e c o u n t r y as w e l l as extending s t e a d i l y f u r t h e r north.

We a r e e s p e c i a l l y concerned salmon

rivers

at

about

the

increasing

acidification

of

the

t h e West coast o f Norway, important as they are b o t h as

t r a d i t i o n a l s i t e s f o r a n g l i n g and as a genepool f o r t h e a t l a n t i c salmon.

So f a r we have focused on t h e a c i d i f i c a t i o n o f lakes South

Norway,

an

area

of

33.000

is

km2

affected.

rivers.

In

I n t h i s area, f i s h

p o p u l a t i o n s a r e e i t h e r e x t i n c t o r d r a s t i c a l l y reduced. researchers

and

Recently,

however,

have r e p o r t e d s i g n s o f e f f e c t s i n Scandinavian f o r e s t s s i m i l a r

t o those observed i n t h e c e n t r a l p a r t s o f Europe. The t r e e s become weakened l e s s t o l e r a n t t o t h e n a t u r a l s t r e s s o f pests, diseases, drought and so

and

on. I n many places, t h e r e i s a s i g n i f i c a n t r e d u c t i o n i n s o i l pH. A

growing

number o f s c i e n t i s t s consider transboundary a i r p o l l u t i o n as a major t h r e a t t o our f o r e s t s . Another f i e l d o f i n c r e a s i n g concern i n Norway a r e t h e enhanced l e v e l s o f toxic

metals

in

the

environment

due

to

long-range

a c i d i f i c a t i o n . Our concern i s p r i m a r i l y focused on t h e copper,

cadmium and

mercury.

The

effects

in

aluminium,

o f t h e i n c r e a s i n g l e v e l s are

a l r e a d y appearing i n b i r d s and w i l d animals. For cadmium

a i r p o l l u t i o n and metals:

instance,

the

level

l i v e r and kidneys i n game i n Southern Norway i s t h e h i g h e s t i n

Europe, and c l e a r l y exceeds t h e l i m i t s o f acceptable d a i l y i n t a k e . result more

is

the

disturbing

significant

reduced is

less

s h e l l t h i c k n e s s of b i r d s e g g s ' l n

the

increase

result

of

a

statistical

we

Another

Norway. Even

survey,

showing

a

i n t h e average age o f people i n t h e areas most

h e a v i l y e f f e c t e d by a c i d r a i n . F u r t h e r s t u d i e s must be conducted, before

of

however,

can e s t a b l i s h t h e cause o r causes o f t h i s r e s u l t . A t t h e moment

we g i v e f i n a n c i a l support t o a study concerning p o s s i b l e h e a l t h e f f e c t s

of

increased l e v e l s o f aluminium i n t a p water.

RESEARCH PROGRAMMES Norway s t a r t e d c o o r d i n a t e d l a r g e

scale

research

on

the

effects

of

transboundary a i r p o l l u t i o n i n 1972 when several research i n s t i t u t e s j o i n e d f o r c e s i n t h e e i g h t year SNSF programme t o

analyse

the

effects

of

acid

p r e c i p i t a t i o n on f o r e s t and f i s h .

A t present about 20 m i l l i o n NOK per year

is

spent

on

this

type

of

427

research

in

Norway.

Of

this

The

M i n i s t r y o f Environment funds about 5

m i l l i o n NOK, s u p p o r t i n g about t w e n t y institutions

across

projects carried

out

the at

projects

country.

The

universities

carried

and

out

by

different

15 m i l l . N O K r e p r e s e n t

remaining

research

institutions.

All

p r o j e c t s a r e s e l e c t e d and f o l l o w e d up by t h e r e s e a r c h c o u n c i l s . Specifically,

I want t o m e n t i o n t w o o f o u r l a r g e s t p r o j e c t s ,

RAIN

and

t h e p r o j e c t " F o r e s t and Environment, growth and v i t a l i t y " . The R A I N - p r o j e c t s , o r R e v e r s i n g A c i d i f i c a t i o n 1984,

as

a

cooperation

between

Norway,

in

Sweden

Norway, commenced i n and

Canada. The b a s i c

philosophy o f t h e p r o j e c t i s , t h a t i t i s s t i l l p o s s i b l e t o r e s t o r e provided

that

nature,

amounts o f d e p o s i t i o n a r e reduced. P r e l i m i n a r y r e s u l t s f r o m

t h e p r o j e c t s show p o s i t i v e r e s u l t s i n t h i s r e s p e c t . The p r o j e c t s w i l l s t i l l continue f o r several years. T h i s y e a r , Norway has s t a r t e d "Forest

and

an

extensive

environment: Growth and V i t a l i t y " .

research

project

called

The p r o j e c t has t h r e e main

aims: 1) M o n i t o r y t h e h e a l t h s t a t e of Norwegian f o r e s t s t o d i s c o v e r e f f e c t s o f a i r p o l l u t i o n as soon as p o s s i b l e . t h e trees tolerance t o 0 in

combinations,

3)

3'

SO

2

Increase

2) Perform e x p e r i m e n t a l s t u d i e s about

and NO , b o t h t e s t i n g each f a c t o r a l o n e our

X

basic

and

knowledge o f t h e f a c t o r s which

r e g u l a t e t r e e growth. By t h e end o f 1985 t h e M i n i s t r y o f Environment national

n a t i o n a l p r i o r i t i e s f o r r e s e a r c h on t r a n s b o u n d a r y this

together

with

several

r e s e a r c h i n s t i t u t i o n s agreed upon a frame programme o u t l i n i n g t h e

process,

air

pollution.

t h e c u r r e n t s t a t e o f t h e a r t was considered.

During

The f o l l o w i n g

a r e a s were p o i n t e d o u t as p a r t i c u l a r l y i m p o r t a n t :

-

t h e e m i s s i o n s o f n i t r o g e n o x i d e s and t h e f o r m a t i o n o f photochemical oxydant s

- t h e e f f e c t s on f o r e s t and o t h e r v e g e t a t i o n - dose response r e l a t i o n s h i p s between t h e d e p o s i t i o n

o f a c i d compounds

and t h e damages t o s o i l , water, f i s h and o t h e r a q u a t i c animals

-

e f f e c t s o f a l u m i n i u m and heavy m e t a l s on human h e a l t h .

As w i l l be w e l l known by t h e p a r t i c i p a n t s t o t h i s conference, Norway p l a c e s h i g h i m p o r t a n c e i n an a c t i v e and e x t e n s i v e exchange o f i n f o r m a t i o n on r e s e a r c h programmes and s c i e n t i f i c r e s u l t s i n t h e f i e l d o f a c i d r a i n .

428

EXPECTED REDUCTIONS OF SO

NO HYDROCARBONS AND AMMONIA EMISSIONS 2’ x’ By 1984 o u r n a t i o n a l e m i s s i o n s of SO were 97.000 tonnes. Thus compared 2 w i t h t h e 1980 e m i s s i o n s we a l r e a d y have a c h i e v e d a 30% r e d u c t i o n . The Government i n t e n d s t o reduce t h e emissions f u r t h e r t o r e a c h 50% o f t h e 1980 levels

by 1993. A p l a n i s under p r e p a r a t i o n by t h e S t a t e P o l l u t i o n C o n t r o l

Agency t o e n s u r e t h a t t h e c u r r e n t l e v e l s

are

retained

and

to

recommend

a c t i o n s t h a t have t o be t a k e n i n o r d e r t o r e a c h t h e goal o f 50% r e d u c t i o n . As a f i r s t s t e p

for

further

reductions

of

sulphur

emissions,

new

r e g u l a t i o n s demanding t h e use o f f u e l o i l w i t h a maximum s u l p h u r c o n t e n t o f 1%i n t h e s o u t h e r n most c o u n t i e s o f Norway were i n t r o d u c e d i n t h e b e g i n n i n g of

It i s e x p e c t e d t h a t t h i s p r o v i s i o n w i l l reduce SO

t h i s year.

i n Norway by a p p r o x i m a t e l y 8.000 t o n n e s a year. As r e g a r d s NO

X

intention

2

emissions

emissions, t h e Norwegian government i n 1984 d e c l a r e d i t s

t o adopt US e m i s s i o n s t a n d a r d s f o r a l l new l i g h t motor v e h i c l e s .

The necessary r e g u l a t i o n s a r e a t p r e s e n t under p r e p a r a t i o n and a r e enter

to

into

force

in

1989.

Norway t h i s i s c a l c u l a t e d t o g i v e a 60-70% r e d u c t i o n o f t h e of

e m i s s i o n s from t h i s t y p e o f source.

c a t a l y t i c converters, p e t r o l s t a t i o n s petrol.

Government

taxes

planned

With t h e p r e s e n t l e v e l o f a u t o m o b i l e s i n

current

level

To p r e p a r e f o r t h e i n t r o d u c t i o n o f in

Norway

already

offer

unleaded

on p e t r o l have been a d j u s t e d t o t h e e f f e c t t h a t

unleaded p e t r o l c a r r i e s a p r i c e premium. A p l a n f o r s t a b i l i z i n g t h e emissions o f n i t r o g e n level

NO

X

and

f u r t h e r r e d u c t i o n s i s under p r e p a r a t i o n s .

for

f r o m s t a t i o n a r y sources a r e r a t h e r l i m i t e d compared t o

mobile

at

the

1983

The emissions o f emissions

from

sources i n Norway, which amounted t o a p p r o x i m a t e l y 85% i n 1982. The

main reason f o r t h i s i s , t h a t we do plants

and

that

control

not

measures

i n d u s t r i a l p l a n t s which had NO

X

expected

to

be

ready

by

have

already

any

fossil

have

been

fuelled

power

implemented

in

e m i s s i o n s o f any s i g n i f i c a n c e .

Our p l a n s f o r t h e r e d u c t i o n o f NO are

oxides

the

X

and t h e f u r t h e r r e d u c t i o n s end

of

this

of

SO

2’

y e a r . They i n c l u d e an

e v a l u a t i o n o f a l t e r n a t i v e a c t i o n s t o be taken, i n c l u d i n g c o s t e f f e c t i v e n e s s analysis.

The

r e s u l t w i l l t a k e t h e f o r m o f a package, p r o v i d i n g a l i s t o f

p r i o r i t i e s o f a c t i o n s t o be t a k e n as a c t i o n s t o be taken.

well

as

a

time

schedule

for

the

429

LIMING Rough c a l c u l a t i o n s show t h a t t h e range o f 340.000 tonnes o f l i m e be

needed

transboundary a i r p o l l u t i o n i n t h e southern p a r t s would

would

annually t o n e u t r a l i z e t h e a c i d water d e p o s i t i o n f o l l o w i n g from

amount

of

Norway

only.

Costs

t o a p p r o x i m a t e l y 250 m i l l i o n NOK a y e a r i n a d d i t i o n t o a one

t i m e c o s t o f 50 m i l l i o n NOK t o l i m e t h e a c i d l a k e s . One o f t h e reasons these

high

figures

is

that

we

have

a

d u r a t i o n o f w a t e r i n Norway t h a n f o r i n s t a n c e i n Sweden. I n such

figures,

should

it

be

evident

for

much l a r g e r r u n o f f and s h o r t e r the

light

of

t o anyone t h a t l i m i n g a l l a f f e c t e d

Norwegian watercneds i s c o m p l e t e l y u n r e a l i s t i c . The Norwegian government i s , however, spending an i n c r e a s i n g amount

of

money f o r l i m i n g , f r o m 4 m i l l i o n NOK i n 1985 t o 7 m i l l i o n NOK i n 1986. T h i s I t i s j u s t b a r e l y enough t o

i s o f c o u r s e f a r f r o m enough. the

most

importance,

severely

affected

the

being

aim

locations to

save

of some

high of

partially

economic

the

and

most

treat

regional

valuable

fish

p o p u l a t i o n s which a r e t h r e a t e n e d . L i m i n g i s , and w i l l c o n t i n u e t o be, j u s t an emergency measure t o use i n limited

a r e a s i n Norway. To s o l v e t h e p r o b l e m o f a c i d i f i c a t i o n , we have t o

go t o t h e source, t o reduce t h e emissions. away

the

symptoms.

It

is

an

Liming

ecological

j u s t temporarily

aspirin

and

takes

not a long term

solution. CONCLUSION B e i n g now a t t h e end o f my statement, where

I started.

advanced models have been presented. although

there

I want t o draw t h e l i n e

back

to

D u r i n g t h i s Conference a number o f s c i e n t i f i c r e s u l t s a n d still

are

I

would

like

to

remind

you

that

many s c i e n t i f i c u n c e r t a i n t i e s , we know t h a t a t

p r e s e n t , t h e l o a d i n g o f long-range a i r p o l l u t i o n i s t o o h i g h . I n Norway t h e r e i s an o l d s a y i n g which goes " w h i l e t h e grass grows, t h e cow

dies".

We

should

see

t o i t t h a t t h e cow, w h i c h i n t h i s case i s

n a t u r e , on which we a t p r e s e n t a r e c a r r y i n g o u t a g i g a n t i c and h i g h l y r i s k y experiment,

does

not

suffer

irrepairable

s c i e n t i f i c knowledge and p e r f e c t models.

damage

while

we

await f u l l

431

T. Schneider (Editor)/Acidificatwon and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

PRESENTATION BY THE ITALIAN DELEGATION

I n s t a r t i n g t h i s b r i e f r e p o r t we would l i k e t o r e c a l l , that

in

assessed 1.410.000

Italy at

for

the

3.800.000

and

year tons

1.500.000

1980 sulphur and

tons

nitrogen

1.537.000

All

t o n s f o r NO these

international

data

X

.

have

been

organizations,

dioxide

f o r t h e same period.

were reduced, r e s p e c t i v e l y , t o 3.150.000

tons

regularly

among

them

first

of

all,

d i o x i d e emissions have been

SO

for

emissions,

2

forwarded the

between

I n 1983 these f i g u r e s and to

1.387.000 all

to

concerned

Executive Body o f t h e 1979

Geneva Convention. As t o t h e I t a l i a n a t t i t u d e w i t h r e f e r e n c e t o

the

initiatives

ECE

on

atmospheric p o l l u t i o n , we may p o i n t o u t t h a t on t h e 15th o f J u l y 1982 I t a l y has r e g i s t e r e d i t s r a t i f i c a t i o n o f t h e Geneva Convention and 9th

that

on

the

o f J u l y 1985 we have signed t h e Protocol t o t h e Convention, r e l a t e d t o emissions by 1993. 2 I t a l y a l s o takes p a r t i n t h e deployment

t h e 30% r e d u c t i o n i n SO policies

aiming

at

controlling

and

of

the

European

p o l i c i e s have already a t t a i n e d a r e l e v a n t m i l e s t o n e through in

the

spring

of

1984,

of

a

Communities

reducing dangerous emissions. These the

adoption,

d i r e c t i v e on t h e c o n t r o l of emissions by

i n d u s t r i a l p l a n t s . W i t h i n t h e framework o f t h e l a t t e r , which i s a s o - c a l l e d "mother

d i r e c t i v e " , we now t a k e p a r t i n t h e p r e p a r a t i o n o f a new d i r e c t i v e

l e a d i n g t o t h e r e d u c t i o n o f emissions by l a r g e combustion p l a n t s . Since t h e matters

raised

by

this

proposal

are

rather

complex,

proceeding f o r some t i m e now, and i t i s w e l l known t h a t has

t a l k s have been

the

whole

matter

been somewhat slowed down. This r u l i n g however, when f i n a l l y approved,

w i l l provide a relevant contribution i n

terms

of

reducing

national

and

transboundary atmospheric p o l l u t i o n . I t a l i a n l e g i s l a t i o n on a i r p o l l u t i o n c o n t r o l i s p r e s e n t l y founded upon

Air

both

Q u a l i t y Standards p r o v i s i o n s as w e l l as upon emission l i m i t s f o r

i n d u s t r i a l p l a n t s e s t a b l i s h e d by t h e v a r i o u s Regions. On t h e 28th o f March 1983 i n I t a l y which, f o l l o w i n g r u l i n g s set down by the

European

permitted f o r

Community, seven

established

polluting

t h e highest. l e v e l s o f c o n c e n t r a t i o n

substances:

SO

2'

NO , 0 x 3'

CO,

F,

Pb,

432

suspended p a r t i c u l a t e d m a t t e r . The decree t h u s e s t a b l i s h e d AQS which a r e i n e f f e c t o v e r t h e whole

national

territory,

regardless

of

the

polluting

source. T h i s AQS a d o p t i o n has b r o u g h t f o r w a r d former

control

procedures

based

on

a

a

c o n c e n t r a t i o n l e v e l s were f i x e d o n l y f o r pollutants

and

this,

only

in

some

new

system

superseding

the

1966 a n t i p o l l u t i o n l a w by which some

given

industry

originated

s o - c a l l e d " c o n t r o l l e d " areas o f o u r

territory. A c c o r d i n g t o t h e 1983 decree, whenever AQS happen t o be surpassed, pertinent

Regions

t h e p r e v i o u s s i t u a t i o n : t h e s e p l a n s s h o u l d i m p l y enforcement upon sources

in

all

the

must implement s p e c i f i c p l a n s a i m i n g a t r e - e s t a b l i s h i n g emission

c o n t r i b u t i n g t o a i r d e g r e d a t i o n , so as t o a t t a i n

sectors

more d e s i r a b l e l e v e l s as soon as p o s s i b l e . I n any case, and l e a v i n g decree

on

AQS

aside

these

particular

r e p u d i a t i o n o f t h e f o r m e r systems based upon pollution

contingencies,

the

meets w i t h t h e b a s i c p r e v e n t i v e s t r a t e g i e s w i t h a d e f i n i t e

interventions,

carried

sporadic

on m a i n l y

and

isolated

anti

i f not only i n particularly

endangered areas. We s h a l l now come t o t h e v a r i o u s p r o v i s i o n s by which we p l a n t o f u r t h e r a c h i e v e c o n t a i n m e n t o f dangerous e m i s s i o n s i n t h e f u t u r e . By t h e N a t i o n a l E n e r g e t i c P l a n v a r i o u s thermo e l e c t r i c

on

fuel

plants

running

o i l ( w i t h a s u l p h u r c o n t e n t o f 3%) s h a l l be s u b s t i t u t e d by p l a n t s

r u n n i n g on c o a l whose s u l p h u r c o n t e n t must n o t exceed, by law, 1%. I f takes

in

account

the

related

one

t h e r m i c c a p a c i t i e s , t h i s s w i t c h may b r i n g

about a r e d u c t i o n by 30% i n s u l p h u r emissions. Again, s u l p h u r c o n t e n t i n g a s o i l , w h i c h a t t h e b e g i n n i n g about

1.1% has

gone

of

1983 was

down s i n c e t h e 1 s t o f J u l y 1985 t o 0.3% f o l l o w i n g a

d e c r e e which b r o u g h t i m p l e m e n t a t i o n

in

Italy

of

a

pertinent

Community

ruling. Another p o s i t i v e f a c t o r i s p r o v i d e d by t h e s w i t c h , which i s in

many

Italian

centres,

from

gasoilmethane,

under

way

mainly i n the f i e l d o f

domestic usage. Coming now t o

the

theme

of

research

performed

in

Italy

on

acid

d e p o s i t i o n , we s h o u l d a t f i r s t r e c a l l t h e e s t a b l i s h m e n t i n o u r c o u n t r y o f 4

433

sampling s t a t i o n s o p e r a t i n g w i t h i n EMEP Programme o f t h e Geneva Convention. Again

on

EMEP,

Italy

has

signed

t h e r e l a t e d f i n a n c i a l p r o t o c o l and i s

p r e s e n t l y proceeding w i t h i t s r a t i f i c a t i o n . We a r e a l s o s t u d y i n g our p o s s i b l e accession i n t o t h e Geneva

Convention

Working Group which i s d e a l i n g w i t h damages t o v a r i o u s m a t e r i a l s as w e l l as monuments, always i n r e l a t i o n t o atmospheric p o l l u t i o n . Again, an o f f i c i a l the

matter

of

research has been r e c e n t l y c a r r i e d o u t i n

our forests.

Italy

on

It has l e d t o t h e c o n c l u s i o n t h a t about 5% o f

f o r e s t s a r e damaged q u i t e p r o b a b l y by p o l l u t i o n and

not

by

other

causes

such as f o r e s t f i r e s . On a r e g i o n a l l e v e l , t h e r e has research

carried

on

in

recent

months

an

extensive

by a "Study Group on t h e chemical c h a r a c t e r i s t i c s o f

r a i n f a l l s i n Northern I t a l y " . This foreign

been group,

formed

20

by

Italian

and

3

l a b o r a t o r i e s , has m a i n l y devoted i t s a t t e n t i o n upon t h e e f f e c t s o f

a c i d d e p o s i t i o n s on t h e environment,

and p a r t i c u l a r l y on t h e l a k e s

in

the

A l p i n e area. The research so f a r conducted has shown t h a t damages pollution

from

atmospheric

have l a r g e l y concerned o u r a r t i s t i c and h i s t o r i c a l h e r i t a g e , and

t h e f o r e s t s i n a l e s s e r way. On t h e m a t t e r o f t h e research performed w i t h i n

the

Geneva

Convention

concerning damages upon v a r i o u s s t r u c t u r e s and m a t e r i a l s , i t i s our o p i n i o n t h a t t h e same amount o f importance which effects

is

presently

conferred

to

the

upon v a r i o u s i n d u s t r i a l m a t e r i a l s should be now a t t r i b u t e d as w e l l

t o t h e consequences s u f f e r e d by stones, bronze and o t h e r m a t e r i a l s

present

i n monuments. I n a l l I t a l i a n c e n t r e s i t i s p o s s i b l e t o a s c e r t a i n damage t o caused

by

atmospheric

f i n d , t h e same as i n o t h e r European domestic

heating

and

by

towns,

industrial

sulphur

combustion

dioxide plants;

d i o x i d e coming from a l l k i n d s o f combustion and above a l l , circulation,

and

monuments

p o l l u t i o n t y p i c a l o f an urban environment.

One can

produced

by

then, n i t r o g e n from

vehicular

then again, c a r b o n i c p a r t i c u l a t e d m a t t e r produced, among

o t h e r s , by d i e s e l engines. L a s t l y , we should s t i l l r e c a l l t h a t i n t h e case of I t a l y , p o l l u t i o n threatening,otherthan

is

by t h e dangerous substances e x i s t i n g i n Northern and

C e n t r a l Europe, a l s o by photochemical p o l l u t a n t s , m a i n l y

including

a l l o f which a r e produced by t h e increased s o l a r i r r i d i a t i o n .

ozone,

T. Schneider (Editor)/Acidificationand its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

43 5

Air pollution abatement policy in Switzerland

by Gerhard Leutert, Swiss Federal Office for Environmental Protection

In Switzerland - like in other countries kedly increased since the fifties. Damages and adverse effects lakes, forest dieback that air pollution is too high and must be

air pollution has marto buildings. acidified on human health show, reduced.

The only way to reduce air pollution is to limit the emission at its source, that means to establish and enforce emission limitations. According to the Swiss federal law on the protection of the environment, all emissions have to be reduced to a practically achievable level even if negative effects are not, or not yet, occurring. Proven air pollution control technology which is economically feasible m u ~ be t applied to reduce emissions. This is a fundamental principle of that law. The following examples show how this legal principle is applied in practice. The objective of this presentation is neither to speak about concepts and ideas, nor to tell what ought to be done, but rather to show what has been done in our country and what has been regulated in a legally binding form. Measures have been taken in each of the three main categories of emission sources: - industry. - heating installations, - motor vehicles.

436 I ndustry

For industrial emission sources a new ordinance on air pollution control (Luftreinhalte-Verordnung, LRV) has been established, which is in force since March 1st. 1986. This ordinance is rather advanced and contains stringent emission limits for industrial plants and installations. The emission limits of this ordinance are widely harmonized with the corresponding values of the new regulations of the Federal Republic of Germany (TA-Luft), although there are also some differences due to different situations in the two countries. The Swiss ordinance on air pollution control contains, with regard to industry emissions. the following main elements: - Generally applicable emission limits are set for about 150 air

pollutants. - Specific emission standards are given for about 40 special types

of plants and installations. - Plants and installations which emit air pollutants have to be

inspected every 3 years.

- The issued emission standards hold for new as well as for old plants, i.e. old plants must be retrofitted.

- Normally, retrofitting of old plants has to be completed within 5

years.

Heatina installations Beyond regulating industrial emissions, the Swiss ordinance on air pollution control contains also progressive regulations for heating installations. The main points in this field are:

437

- Emission standards are set . depending on the combustibles used (i.e. oil, coal, wood. gas)

.

and for all sizes of installations (ranging from domestic heatings up to power plants).

- Heating installations have to be inspected every

2

years.

- Domestic oil heating equipment has to undergo a type approval test regarding emissions.

- Large oil and coal fired plants with a thermal power exceeding 100 MW have to be equipped with a flue gas desulphurization. - Retrofitting of old installations has normally to be completed

within 5 years. - Limits are set for sulphur content in fuels.

According to the Swiss ordinance on air pollution control, the sulphur content of gas oil for domestic heatings must not exceed 0 . 2 percent (by weight) after July 1st. 1987. This value holds not only forheavily polluted areas, but for the whole country. With this regulation, Switzerland probably has the most advanced regulation in the world. For heavy fuel oil, the maximum sulphur' content is limited to 1.5 percent with effect from July 1st. 1986, and to 1.0 percent from July 1st. 1991. The development of the Swiss legal sulphur limits for gas oil and heavy fuel oil are shown in figures 1 and 2 respectively.

438

Sulphur content

4

1972 F i g . 1:

1 . 1 .1985

1.7.1987

Maximum a d m i s s i b l e s u l p h u r c o n t e n t f o r g a s o i l

Sulphur content

x!

1972 Fig. 2:

1.7.1986

1.7.1991

Maximum a d m i s s i b l e s u l p h u r c o n t e n t f o r heavy fuel o i l

439

Motor vehicles For this important source of air pollution there exist a number of regulations which aim to reduce the emission of air pollutants. The main elements are:

-

Speed limits, which have been lowered for air pollution reasons to :

. .

80 km/h on roads outside towns and villages; 120 km/h on motorways.

- Regular quality petrol must be unleaded.

-

Tax reduction on unleaded petrol. which amounts to a price difference of about 5 percent compared to the leaded premium quality.

-

Emission standards for motorcycles (ECE 40) and mopeds (ECE 47).

- Emission standards for trucks (ECE 24).

-

Emission standards for passenger cars: . Swiss standards 1982 . Swiss standards 1986 . US 81/83 standards in 1987 . yearly inspection and maintenance regarding exhaust gas emissions.

At the present time (May 1986). the emission standards for motorcycles, mopeds and trucks, which were valid so far in Switzerland, are under discussion. The experience has shown that these ECE standards do not give rise to an effective reduction of the exhaust gas emissions of these vehicles. The Swiss government therefore plans to establish new, both more effective and more stringent emission standards for these vehicle categories. A similar situation existed already in 1981 regarding passenger cars. At that time Switzerland had to denounce the ECE 15 reglementation and to establish more stringent emission standards for passenger cars, due to environmental needs. As a further marked step, the US 1981/83 standards will be put into force in Switzerland in 1987. These

440

standards reflect today's state of the art in the field of air pollution abatement for passenger cars. A number of other countries have already introduced or intend to introduce these standards, e.g. USA, Canada, Sweden. Norway. Denmark. Austria and Liechtenstein. On the other hand, the Commission of the European Community proposes different and less advanced emission standards which should come into force in the years 1989, 1991 and 1993 respectively. Figure 3 shows a comparison of different emission standards for passenger cars.

CH 87 CH 86 (=US 77) (=US 81/83)

....,

..... :.:.:.:.,

.:.:.:::: ...

F i g . 3:

Carbon monoxide

(CO)

Hydrocarbons

(HC)

N i t r o g e n oxides

(NOx)

EG 89

>2,ot

EG 91

< 1,4e

EG 93 1,4-2 ,Or

D i f f e r e n t exhaust gas emission standards f o r passenger cars

44 1

Outlook Switzerland has already taken a number of remarkable decisions to abate air pollution. However, further measures are needed to achieve an air quality which is not unhealthy to man and his environment. We will continue fighting air pollution as we did in the last years in our country, and we will continue to play an active role also at the international level. To solve transboundary air pollution problems, international cooperation is necessary. However: Seeking for internationally harmonized solutions must not lead to undue delays or undue weakening of necessary and feasible measures. One of the main reasons for the urgency and severity of the measures taken in Switzerland is the preservation of our mountain forests. Their protective function against avalanches, landslides and floods is essential for survival in these regions. What can be done against too high air pollution and forest dieback abe done. preferably internationally harmonized, but in case of need at least on a national basis. Unfortunately, the experience shows, that international harmonization in the field of the environmental protection often leads to undue delays and weakening of such regulations. The story of the European exhaust gas limits for motor vehicles gives a recent example. The protection of man and his environment needs not only common, but advanced and proaressive measures. Switzerland has fixed such regulations in a compulsory form. Some other countries and international organisations have not yet advanced as far. We encourage them to follow the same course in setting stringent emission limits which Switzerland and others have proven to be realistic ones.

443

T. Schneider (Editor)/Acidificatwnand its Policy Zmplicatwns Elsevier Science Publishers B.V., Amsterdam - Printed in The Nethgrlands

POLITIQUE FRANCAISE POUR LUTTER CONTRE LES PLUIES ACIDES Ces d e r n i e r e s annees pollutions

ont

d

transportees

Scandinaves e t Nord-americains,

mis

en

evidence

des

effets

nefastes

grande

distance

(acidification

de

des

deperissement des f o r e t s d'Europe

...

lacs mais

egalement degradation du p a t r i m o i n e a r c h i t e c t u r a l ) . &t&

En France, l e s premiers symptomes de deperissement des f o r e e t s o n t

constatees en 1983 dans l e s Vosges, apres une periode de secheresse p u i s se sont progressivement Ctendus d l'ensemble du massif f o r e s t i e r . Au vu des recherches e n t r e p r i s e s , l e deperissement des f o r e t s generalement

de

certains

vegCtaux

semble

&re

la

et

consequence

p o l l u t i o n de 1 ' a i r ( p o l l u t i o n a c i d e e t photooxydante) agissant en

plus de

la

synergie

avec d ' a u t r e s phCnomenes t e l s que l e climat... L ' o b j e t de c e t expose e s t de vous presenter l e s mesures p r i s e s

par

la

FRANCE pour l u t t e r efficacement c o n t r e l e phenom&ne des " p l u i e s acides". Ces mesures comportent t r o i s v o l e t s d i s t i n c t s :

-

mis en p l a c e d'une reglementation en vue de r e d u i r e l e s emiss i o n s des p o l l u a n t s

-

renforcement de l a s u r v e i l l a n c e de l a p o l l u t i o n de l ' a i r

- actions

de formation, de recherche e t d ' i n f o r m a t i o n .

P R E V I S I O N S DE L'EVOLUTION DES EMISSIONS DES POLLUANTS SO

ET HYDROCARBURES JUSQU'A L ' A N 2000. ENGAGEMENT PRIS

2' PAR LA

NO

FRRNCE

EN MATIERE DE REDUCTION DES EMISSIONS Ces p r e c i s i o n s d t a b l i s d energetiques

d

1 'horizon

partir

2000

d'une

etude

indiquent,

sur

suivant,

les les

consommations dispositions

reglementaires q u i seront adoptees ou non que:

-

pour l e s emissions de SO

d 1 'annee 1980 pour l e s &missions de NO

d l ' a n n e e 1979

2

X

une d i m i n u t i o n de 58 d 70% par r a p p o r t une d i m i n u t i o n de 20 d 35% par r a p p o r t

pour l e s emissions d'hydrocarbures une d i m i n u t i o n de 30% par rapp o r t d 1 'annee 1983

444

Les

tableaux

joints

au

document

detail lent

les

previsions

de

1 ' e v o l u t i o n des emissions & 1 ' h o r i z o n 2000 p a r secteur d ' a c t i v i t e s . Dans l e c o n t e x t e a c t u e l , l a FRANCE s ' e s t d e j d

engagbe

d

rbduire

ses

emissions d'oxydes de s o u f r e de 50% e n t r e l e s anndes 1980 e t 1990. En o u t r e l ' o b j e c t i f r e t e n u en ce q u i

concerne

la

pollution

par

les

hydrocarbures e s t une r e d u c t i o n de 30% avant l a f i n du s i e c l e . Ces r e s u l t a t s seront obtenus notamment par l a mise en p l a c e des mesures s u i vantes: E x t e n t i o n e t renforcement des zones d ' a l e r t e e t des zones de p r o t e c t i o n s p e c i a l e c o n t r e l a p o l l u t i o n de 1 ' a i r . Reduction de l a teneur en s o u f r e du gazole e t du f i o u l domestique. La FRANCE proposera qu'une v a l e u r maximale unique s o i t f i x e e au niveau europeen. La FRANCE appuiera l'avancement des n e g o c i a t i o n s comnunaut a i r e s en vue de l ' a d o p t i o n de l a d i r e c t i v e r e l a t i v e aux grandes i n s t a l l a t i o n s de combustion a i n s i que l e s i n i t i a t i v e s de l a commiss i o n en vue de g e n e r a l i s e r e t d'harmoniser l e s l i m i t a t i o n s de v i tesse. A c t i o n s s e c t o r i e l l e s concernant l e s p r i n c i p a l e s branches r e s ponsables des h i s s i o n s d'hydrocarbures (stockages d'hydrocarbures, a c t i v i t e s u t i l i s a n t des s o l v a n t s hydrocarbures comme 1 ' i m p r i merie, l ' a p p l i c a t i o n de p e i n t u r e ...). Dkveloppement de l ' i n s t r u m e n t a t i o n de mesure des p o l l u a n t s concern&

d 1 'emission e t dans 1 'environnement.

RENFORCEMENT DE LA SURVEILLANCE

Les a c t i o n s prevues sont: a ) l a p o u r s u i t e de l a mise en p l a c e d'un reseau de mesure de l a p o l l u t i o n en m i l i e u nature1 comprenant en 1986:

*

l'achevement d'un reseau "retornbees acides" (18 s t a t i o n s

*

l a r e a l i s a t i o n de 6 s t a t i o n s de mesure de l a p o l l u t i o n photo-

" p l u i e s SO2") oxydante q u i s ' a j o u t e r o n t d une s t a t i o n d e j d constate en A1 sace

445

b)

renforcement des moyens des a s s o c i a t i o n s de g e s t i o n des r e seaux de s u r v e i l l a n c e de l a p o l l u t i o n atmospherique (equipement, fonctionnement, modernisation, a c t i o n s d ' i n f o r m a t i o n ...)

cj

achevement de l a couverture du t e r r i t o i r e f o r e s t i e r en p l a c e t t e s d ' o b s e r v a t i o n e t extension e v e n t u e l l e d d ' a u t r e s c u l t u r e s dans l e s zones l e s p l u s s e n s i b l e s ; A ce t i t r e , l e s r e s u l t a t s p r o v i s o i r e s de l a campagne d'observations

de 1985 montrent que: 1) l a s i t u a t i o n e s t s t a b i l i s e e dans l e s zones observees depuis p l u s i e u r s annees 2) des deperissements o n t

etc

constates dans des zones

observees pour l a premieere f o i s . Les d C g i t s l e s p l u s importants sont s i t u e s en Alsace oh 32% des sapins, 10% des Epiceas e t 27% des p i n s s i l v e s t r e o n t perdu p l u s du q u a r t de l e u r s

a i g u i 1 1es. Oes degats o n t egalement

ete

constates

en

Lorraine,

Franche-Comte,

RhBne-A1 pes e t Auvergne. FORMATION, RECHERCHE ET INFORMATION A) Les prograrrmes des U n i v e r s i t e s , des ecoles d ' i n g e n i e u r s e t de l'enseignement technique sont o u v e r t s aux problemes de l a p o l l u t i o n atmosphbrique. L'observation sylvicoles

des

phenomenes

de

deperissement

et

les

l e s programmes

de

formation

initiale

et

continue

des

techniciens

ingenieurs forestiers.

B) Un e f f o r t de recherche fondamentale sur l e s p l u i e s acides e s t developpe sous 1 ' i n t i t u l e programme DEFORPA (depbrissement des f o r 6 t s a t t r i b u a b l e d l a p o l l u t i o n atmosphbrique). Ce programme comprend c i n q themes de recherche:

-

techniques

permettant d'en p a l l i e r l e s inconvenients sont i n t r o d u i t e s dans

a c t i o n de s u r v e i l l a n c e e t d ' e v a l u a t i o n des dommages

et

446

- i d e n t i f i c a t i o n des agents e t des causes du deperissement - mesure de l a p o l l u t i o n atmosph6rique (dep6ts secs e t humides) i n t e r p r e t a t i o n

- mbcanismes -

des r e s u l t a t s

p h y s i o l o g i q u e s de 1 ' a c t i o n des p o l l u a n t s

experimentations vegetales

-

r e l a t i o n dose e f f e t s .

Dans l e cadre de ce programme, l e s recherches s c i e n t i f i q u e s disposeront d'une

station

laboratoire

complete

install4

dans

le

m a s s i f vosgien d

p r o x i m i t e du m a s s i f vosgien (Alsace). a ) Dans l e cadre du programme m o b i l i s a t e u r "Moderniser l e s processus de p r o d u c t i o n " , une 1 igne budgetai r e p a r t ic u l ie r e sera consacree au developpement des t e c h n o l o g i e s de r e d u c t i o n des p o l l u t i o n ( p l a n t r i e n n a l de recherche 1986-1988). b ) Les c o n s t r u c t e u r s automobiles f r a q a i s se sont engages d prendre des mesures pour a m e l i o r e r I ' i n f o r m a t i o n du p u b l i c s u r l a p o l l u t i o n automobile e t sur l e s moyens propres d l a r e d u i r e . Le M i n i s t r e Delegue charge de 1'Environnement i n c i t e r a l e s

A

developper

po 11 ut ion "

.

entreprises

l a p r a t i q u e de l ' a u t o s u r v e i l l a n c e des emissions e t du " b i l a n

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

447

D e c l a r a t i o n of t h e F e d e r a l Republic o f Germany

N a t i o n a l Research Programmes and P o l i c y on A c i d i f i c a t i o n by D r . Gerhard Feldhaus F e d e r a l M i n i s t r y of t h e I n t e r i o r

ABSTRACT Research i n t o a c i d i f i c a t i o n f o c u s s e s on c a u s e / e f f e c t s o f f o r e s t damages. F u r t h e r s u b j e c t s are damages t o waters, materials, h i s t o r i c monuments. Long-range d i s p e r s i o n and chemical t r a n s f o r m a t i o n o f a i r p o l l u t a n t s w i l l be s t u d i e d by t h e EUROTRAC programme w i t h i n t h e EUREKA r e s e a r c h a c t i v i t i e s . S t u d i e s of transboundary f l u x e s are being commissioned as w e l l . Measures aiming a t a r e d u c t i o n o f SO2, NOx and hydrocarbon emissions a r e p u t i n t o effect. Due t o t h e s e measures a d e c r e a s e o f n a t i o n a l SO emissions from t h e p r e s e n t approximately 3 m i l l i o n t/a t o 1.6 m i l l i o n t?a i n 1988, and f i n a l l y t o less t h a n 1.2 m i l l i o n t/a i n 1993 i s expected. I n t h e case of NOx emissions a d e c r e a s e from approximately 3.1 m i l l i o n t / a i n 1982 t o l e s s than 2.5 m i l l i o n t / a by 1988, and e v e n t u a l l y t o less t h a n 1.6 m i l l i o n t / a by 1993 is e s t i m a t e d . Organic compounds emissions a r e being e s t i m a t e d t o d e c r e a s e from approximately 1.8 m i l l i o n t / a i n 1978 t o approximately 0.9 m i l l i o n t / a by t h e middle o f t h e 1990ies. The government of t h e F e d e r a l Republic of Germany, t o g e t h e r w i t h t e n more c o u n t r i e s , s u g g e s t s t h a t n e g o a t i a t i o n s start w i t h i n t h e UN ECE a s e a r l y as this year on a P r o t o c o l concerning t h e r e d u c t i o n of NOx and hydrocarbon emissions. It-is furthermore requested t o make binding p r o v i s i o n s under i n t e r n a t i o n a l law a t a n e a r l y d a t e for t h e d r a s t i c r e d u c t i o n of t h e s e e m i s s i o n s w i t h i n a c e r t a i n p e r i o d o f time, whereby b e s t a v a i l a b l e r e d u c t i o n t e c h n o l o g i e s should s e r v e as a g u i d i n g p r i n ciple.

448 This conference is a follow-up t o a d e c i s i o n of t h e M u l t i l a t e r a l Conference

on t h e Environment

held

i n Munich

in

1984.

Participating countries

committed themselves t o r e g u l a r l y convening i n t e r n a t i o n a l symposia f o r t h e exchange of t h e l a t e s t s c i e n t i f i c f i n d i n g s on a c i d i f i c a t i o n and long-range transboundary a i r p o l l u t i o n as w e l l as t o d i s c u s s t h e i r i m p l i c a t i o n s f o r p o l i t i c a l measures. The government of t h e Netherlands i n cooperation with t h e UN ECE has now put t h i s d e c i s i o n i n t o e f f e c t . On behalf of my government I should l i k e t o express my warmest thanks t o M i n i s t e r Winsemius f o r having taken t h i s i n i t i a t i v e , t o convene t h i s very importent conference i n cooperation with t h e

Em. I should l i k e t o c o n g r a t u l a t e t h e o r g a n i z e r s of t h e conference f o r t h e i r e x c e l l e n t p r e p a r a t o r y work as w e l l as f o r e n s u r i n g t h e very smooth progress of t h e meetings. Furthermore I should l i k e t o mention our apprec i a t i o n f o r t h e o u t s t a n d i n g h o s p i t a l i t y extended t o us. I n t h e course of t h i s week w e have acquired f u r t h e r d e t a i l e d knowledge of r e c e n t r e s u l t s of e f f e c t s research. Uncertainces concerning t h e e f f e c t s and t h e e x t e n t of damages by a c i d d e p o s i t i o n and photo-oxidants have subsequently been f u r t h e r minimized. Likewise, u n c e r t a i n t y about t h e urgency o f t a k i n g measures t o considerably reduce acid-forming sulphurdioxide and nitrogenoxides emissions as w e l l as photo-oxidants-forming

nitrogenoxides and hydrocarbons , has a l s o been re-

moved. T h i s is being confirmed by f i n d i n g s of our e x t e n s i v e n a t i o n a l res e a r c h programme, i n p a r t i c u l a r f o r t h e f o r e s t damages. S i n c e t h e most s e v e r e damages are t o be observed i n our f o r e s t s , research i n t o t h e causes of t h e s e types of damages was i n t e n s i f i e d s i n c e t h e beginning of 1983. October 1983 saw t h e launching of t h e a c t i o n programme Y3ave our Forests11, which combines r e s e a r c h and p r a c t i c a l measures f o r emission reductions. The main f i e l d s of r e s e a r c h are:

o

assessment of f o r e s t damages

o

mechanisms of damages

449 o

a i r q u a l i t y and d e p o s i t i o n i n f o r e s t areas

o

d i s p e r s i o n , t r a n s f o r m a t i o n and d e p o s i t i o n o f a i r p o l l u t a n t s

o

development and improvement o f m i s s i o n c o n t r o l t e c h n i q u e s .

S i n c e t h e n r e s e a r c h p r o j e c t s a r e being f i n a n c e d by funds amounting t o Deutschmark

90 m i l l i o n .

These p r o j e c t s i n v e s t i g a t e mainly t h e a r e a of

c a u s e / e f f e c t by a i r p o l l u t a n t s . Furthermore, f o r e s t r y measures which could c o n t r i b u t e t o a s t a b i l i z a t i o n o f endangered f o r e s t s , are b e i w considered. Research i n t o effects of a i r p o l l u t a n t s on m a t e r i a l s and h i s t o r i c monuments

i s focussed upon t h e assessment and e v a l u a t i o n o f damages t o p a r t i c u l a r l y s e n s i t i v e m a t e r i a l s . I n t h e c a s e o f s p e c i a l materials, such a s polymeres, and o b j e c t s , such as medieval s t a i n e d g l a s windows and museum e x h i b i t s p a s s i v e p r o t e c t i v e measures have been i n v e s t i g a t e d . The l a t t e r a r e a l r e a d y e f f e c t i v e i n t h e p r e s e r v a t i o n of monuments. Emphasis is l a i d on the i n v e s t i g a t i o n o f a c i d i f i c a t i o n of s u r f a c e w a t e r s and on t h e a s c e r t a i n m e n t of r e l a t e d damages. For t h i s r e a s o n , t h e F e d e r a l M i n i s t e r of t h e I n t e r i o r h a s made funds a v a i l a b l e amounting t o a t o t a l of Deutschmark 5.1 m i l l i o n f o r t h e f u n d i n g of r e s e a r c h p r o j e c t s s i n c e 1983. Here, t h e i n v e s t i g a t i o n of impacts of a c i d i f y i n g s u b s t a n c e s on t h e q u a l i t y o f ground and s u r f a c e waters i s of major importance. The e v a l u a t i o n of t h e r e s u l t s by u s i n g uniform methods as w e l l as monitoring i n s p e c i a l a r e a s are o f primary importance. S t a r t i n g i n 1986 €Re F e d e r a l Republic of Germany w i l l t a k e p a r t i n t h e ECE monitoring programme of a c i d i f i e d w a t e r s due t o a i r pollutants. I n t h e F e d e r a l Republic of Germany forest damages are e s t i m a t e d t o a t l e a s t 1 B i l l i o n Deutsch-Mark per y e a r ; damages t o b u i l d i n g s and o t h e r m a t e r i a l s , h i s t o r i c a l monuments a s w e l l as on s t a i n e d

-

g l a s s windows may come up t o

n e a r l y 3 B i l l i o n Deutsch-Mark per y e a r . I n a r e c e n t s t u d y a p r e d i c t i o n was made t o c a l c u l a t e f u t u r e c o s t s . The f o r e c a s t assumes i n Europe a r e d u c t i o n of s u l p h u r d i o x i d e d e p o s i t i o n by 40 $ and a n i t r o g e n d i o x i d e d e p o s i t i o n by 30 % b e f o r e 1996. Even under t h i s

450

improved c o n d i t i o n s t h e f o r e c a s t estimates y e a r l y c o s t s by damages t o fo-

rests t o around 2 B i l l i o n Deutsch-Mark p e r y e a r , caused by s t i l l i n c r e a s i n g f o r e s t damages. F o r e s t damages are a n i n d i c a t o r i n o u r t i m e f o r t h e n e g l e c t i n t h e p a s t . A l l i n d u s t r i a l i z e d n a t i o n s have experienced a comparable development throughout t h e c e n t u r y i n terms o f a n almost s t e a d y growth i n a i r p o l l u t i o n , It i s o n l y now, t h a t t h i s development is i n d i c a t i n g a r e v e r s e t r e n d . And w e c a l l on a l l c o u n t r i e s , i n t h e i r common i n t e r e s t , t o t a k e f u r t h e r c o o p e r a t i v e and effect i v e measures t o reduce emissions and c o n s i d e r a b l y lower t h e e x p o r t and import of a i r p o l l u t a n t s . Alongside t h e a i r q u a l i t y p r o t e c t i o n p o l i c y w i t h i n t h e European Commu-

nities, t h e r e f o r e , t h e government of t h e F e d e r a l Republic of Germany cons i d e r s t h e implementation o f t h e Convention of 1979 on t h e Long-Range Transboundary a i r p o l l u t i o n t o be o f utmost importance. I n r e c e n t y e a r s , my government has i n t r o d u c e d a number of p r a c t i c a l measures on a n a t i o n a l l e v e l aimed a t t h e improvement of our own environment and d i s p l a y i n g a concern for t h e environment of our European neighbours. The key element of our measures is t h e mandatory r e t r o f i t t i n g of e x i s t i n g large-scale

f u r n a c e s w i t h f l u e g a s t r e a t m e n t equipment w i t h i n s t i p u l a t e d

s h o r t p e r i o d s of time.

y .

I n d u s t r y has a l r e a d y s t a r t e d r e t r o f i t t i n g and modernization; i n p a r t i c u l a r t h e e l e c t r i c i t y g e n e r a t i n g i n d u s t r y h a s a l r e a d y s t a r t e d t o equip e x i s t i n g power p l a n t s w i t h new f l u e g a s c l e a n i n g f a c i l i t i e s . The A s s o c i a t i o n of German E l e c t r i c i t y S u p p l i e r s informed us t h a t a l r e a d y a t t h e end of 1985 one t h i r d of t h o s e power p l a n t s t h a t are s u b j e c t t o r e t r o f i t t i n g was equipped with f l u e gas desulphurization. According t o l a t e s t p l a n s , 80 $ o f e x i s t i n g c o a l and o i l f i r e d power p l a n t s of t h e p u b l i c e l e c t r i c i t y supply w i l l be f i t t e d w i t h f l u e gas desulphuriz a t i o n p l a n t s o v e r t h e n e x t y e a r s . The remaining 20 $ w i l l be c l o s e d down by 1993 a t t h e l a t e s t . E x t e n s i v e r e t r o f i t t i n g of a l l o l d i n d u s t r i a l p l a n t s i s a l s o being c a r r i e d o u t .

451

A t t h e same time f o r a l l i n d u s t r i a l p l a n t s emission s t a n d a r d s

f o r sulphurdioxide an nitrogenoxides

- have

-

also those

been t i g h t e n e d up i n accordance

w i t h t h e l a t e s t s t a t e o f technology. These emission r e d u c t i o n measures a r e supplemented by t h e Intended r e d u c t i o n o f s u l p h u r i n l i g h t f u e l o i l as w e l l

as by t h e s u c c e s s f u l i n t r o d u c t i o n of t h e low-pollution c a r s , esp. by t a x r e d u c t i o n measures. I n consequence t o t h e s e and o t h e r r e g u l a t o r y measures a d e c r e a s e of n a t i o n a l sulphurdioxide-emissions from t h e p r e s e n t approximately 3 m i l l i o n t o n s per y e a r t o 1.6 m i l l i o n t o n s i n 1988 and f i n a l l y t o l e s s t h a n 1.2 m i l l i o n t o n s per y e a r i n 1993 is expected. We t h u s will be more t h a n f u l f i l l i n g o u r commitment t o t h e H e l s i n k i P r o t o c o l on t h e r e d u c t i o n o f s u l p h u r emission i n

terms o f both t i m e and r e d u c t i o n rate. N a t i o n a l nitrogenoxides-emissions are expected t o have decreased by 1993 as follows:

from approximately 3.1 m i l l i o n t o n s i n 1982 t o less than 2.5

m i l l i o n t o n s by 1988, and e v e n t u a l l y t o less t h a n 1.6 m i l l i o n t o n s by 1993. The f i r s t l a r g e - s c a l e f a c i l i t y f o r a c a t a l y t i c NOx r e d u c t i o n s t a r t e d ope-

ration a t a power p l a n t a t t h e end of 1985. N a t i o n a l organic-compounds emissions are e s t i m a t e d t o have decreased by t h e middle of t h e n i n e t i e s a s follows: from a maximum of 1.8 m i l l i o n t o n s p e r y e a r i n 1978 t o 1.6 m i l l i o n t o n s a t t h e p r e s e n t time, t o approximately 0.9 m i l l i o n tons per year i n t h e n i n e t i e s . A c a l c u l a t i o n of t h e d e c r e a s e of a c i d d e p o s i t i o n as a r e s u l t of emission

r e d u c t i o n measures i s p o s s i b l e , i f t r a n s p o r t a t i o n and t r a n s f o r m a t i o n proc e s s e s are modelled. It i s estimated t h a t a 50 percent r e d u c t i o n of sulphurd i o x i d e emission i n t h e F e d e r a l Republic of Germany w i l l l e a d t o t h e f o l l o w i n g d e c r e a s e of s u l p h u r d e p o s i t i o n :

a r e d u c t i o n from t h e p r e s e n t

35 mg p e r s q u a r e meter p e r day t o 25 mg i n h e a v i l y p o l l u t e d areas, and from p r e s e n t 12 mg t o 9.5 mg o f s u l p h u r per s q u a r e meter per day i n less p o l l u t e d r u r a l areas. I n l a r g e areas of C e n t r a l Europe s u l p h u r d e p o s i t i o n s t i l l amounts t o 12 mg per s q u a r e meter p e r day o r even more. T h i s is d e f i n i t i v e l y t o o high. A t a

r a t e o f less t h a n 4 mg p e r s q u a r e meter p e r day only,one can assume t h a t no long-term effects on, f o r example, l a k e s will occur. T h i s d e p o s i t i o n r a t e can o n l y be achieved by i n t e r n a t i o n a l measures.

452

It is

o

t h e r e f o r e important t h a t

t h e s u l p h u r p r o t o c o l r a p i d l y becomes e f f e c t i v e and is implemented accordingly

o

more s t a t e s s i g n t h e p r o t o c o l and

o

t h a t , as a f u r t h e r development of t h e p r o t o c o l , f u r t h e r r e d u c t i o n s of s u l p h u r e m i s s i o n s are made w i t h i n a s h o r t t i m e .

A t t h i s s t a g e o f my remarks I should l i k e t o r e i t e r a t e t h e a p p e a l which we

made a t H e l s i n k i last J u l y . We r e q u e s t e d t h a t r e d u c t i o n measures on t h e second p r i o r i t y p o l l u t a n t ,

t h e nitrogenoxides,

be t r e a t e d w i t h t h e same

r e s o l u t i o n as i n t h e case of sulphur. I am convinced t h a t we cannot a f f o r d t o postpone t h i s u r g e n t problem much l o n g e r without r u n n i n g t h e r i s k of having t o cme t o terms w i t h i r r e m e d i a l longer-term damages through a c i d i f i c t i o n and photo-oxidants. As a first s t e p , a Working Group on NOx was e s t a b l i s h e d i n J u l y 1985 i n

H e l s i n k i . T h i s p a n e l has t h e m a n d a t e t o work o u t a b a s i s f o r a p p r o p r i a t e measures and make p r o p o s a l s f o r t h e r e d u c t i o n of nitrogenoxides-emissions. This reporting period is

t o be contained w i t h i n as

s h o r t a p e r i o d as

p o s s i b l e t o f a c i l i t a t e a r a p i d agreement on a NOx P r o t o c o l . The government of t h e F e d e r a l Republic of Germany l e n d s i t s f u l l s u p p o r t t o any a c t i v i t y designed t o speed up t h i s p r o c e s s . A t t h e first meeting of t h e NO

X

Working Group l a s t y e a r t h e d e l e g a t i o n from my c o u n t r y a l r e a d y proposed

p o s s i b l e c o n s t i t u e n t elements f o r such a P r o t o c o l .

We are f u r t h e r m o r e o f t h e opinion t h a t i n view o f dangers and damages caused by photo-oxidants a r e d u c t i o n of hydrocarbon emissions should be agreed upon a l s soon as p o s s i b l e . I n t h i s connection l e t me refer t o t h e d e c l a r a t i o n pronounced l a s t February

a t S a a s Fee. The environment m i n i s t e r s o f eleven states made t h e p a r t i c u l a r , u r g e n t r e q u e s t t h a t t h e c o n t r a c t i n g p a r t i e s s t a r t n e g o t i a t i o n s as e a r l y a s t h i s year on a P r o t o c o l concerning t h e r e d u c t i o n of n i t r o g e n o x i d e s and hydrocarbons-emissions.

I t i s furthermore r e q u e s t e d t o make binding pro-

453 v i s i o n s under i n t e r n a t i o n a l law a t an e a r l y d a t e f o r t h e d r a s t i c r e d u c t i o n

of t h e s e em i s s io n s w i t h i n a c e r t a i n p e r i o d of time; b e s t a v a i l a b l e r e d u c t i o n t e c h n o l o g i e s s h o u ld s e r v e as a g u i d i n g p r i n c i p l e . I t r u s t t h a t on t h e b a s i s of b o t h t h e outcome of t h i s co n f er en ce h e r e i n

Amsterdam and t h e work of t h e NOx Working Group t h e Ex ecu t i v e Body o f t h e ECE-Convention w i l l t a k e t h e n e c e s s a r y s t e p s .

455

T. Schneider (Editor)/Acidificationand its Policy Implications Elsevier Science PublishersB.V., Amsterdam - Printed in The Netherlands

PRESENTATION BY THE DELEGATION OF TURKEY

Mr.Chairman, first of all on behalf of my delegation I would express our

thanks to

like

to

the host country for this meeting and for the

excellent way in which it has been organized. The Dutch Government has taken this very positive initiative to convene this

Conference which gives us the opportunity to discuss one of the main

problems of air pollution. I would also like to express my gratitude to the ECE that has provided its cooperation in organizing this Conference. We realize that this Conference is an excellent opportunity to

discuss

possible ways and means to strengthen our efforts to combat acid rain. During the last couple of years environmental problems have been surging and

consciousness of

the general public increased very fast in

Turkey. However, our environmental problems are those

rather

different from

in Central and Western Europe, and mainly result from regionally

unbalanced industrialization and rapid urbanization. Air pollution in Turkey is not a wide-spread phenomenon but

poses

mainly local problems in certain cities and zones. "Basic Targets and Strategy of the Fifth Five Year Development Plan (1985-1989)" aims at handling environmental problems in a comprehensive and coordinated way to prevent deterioration and to secure the

development of

natural and man-made environment. According to this Plan, measures will be adopted to remove or reduce to a minimum the

factors that particularly

cause air and water pollution. For the sake of protecting the human health and living beings it also says that programmes and projects will rapidly be drawn up

and put into execution on priority in locations where pollution

and destruction are dense. On the other hand, during the Fifth Plan Period part of

the energy

demand will be met by natural gas and geothermal resources and also supply of additional energy provision will be targeted through the natural gas extraction projects from the neighbouring countries. In addition to the above provisions, the Government Programme considers the

air pollution problem as a combined approach of short and long term

measures. According to this program necessary and urgent measures will be taken in Ankara and the other cities which have air pollution problems. For this purpose, provisions will be made to supply sufficient amounts of

fuel

456

of high quality and studies on projects to bring comprehensive solutions to the problem will be started, also options for central heating in the cities with

dense

air pollution problems and measures to decrease the population

density of the urban settlements will be considered. In our country the share of fossil fuels, which sources of

is

one

of

the main

air pollution, is 66% in the total primary energy production,

and 74% in the total energy consumption. Lignities which greatest reserve

comprise the

in relation to other fuel sources make up for 17% o f our

total consumption. The ash rate of our lignities, as a whole is 10-50% and their total sulphur 1-5%. Approximately 43.5% of the final energy consumption is used

in the

housing sector, 31% in industry and 5.6% in the transportation sector. But it should be noted that this consumption is not

totally utilized energy;

the rate of utilized energy which is approximately 45% in Western Europe is estimated to be lower in our country. In Turkey 46.6% of total energy produced

is

thermal

energy

and

53%

comes from lignite and charcoal. Forests in Turkey are generally located far from the and

the

settlements areas. Because of

industrial sites

the climatic conditions damages

caused by the forest fires, insects and fungi are much more important thant the

air pollution in the short range. But it is obvious that as the number

of industries and power plants increases with time, the

level of damage

will increase widely unless otherwise necessary measures are taken. There have been several studies about the impact of

air pollution on

forests caused by Murgul Copper works, Emet Borax Mine Works and Karadeniz Copper Works in Artvin discharges approximately 30.000 year, SO2

emissions from both

tons

of

SO2

per

factories are converted to H2S04 by the

increase of relative humidity in the atmosphere from time to time, and this phenomenon causes the acid precipitation, which damages broad leaved plants and corrodes the

furniture and other materials, and results in huge

economic losses. It has been determined that

these emissions damage

especially plants like tobacco, corn and spinach, fruits like peach, apple and

tomato, and decrease their fertility and also damage by acidification

caused crops to be burned and plowed under. Also villagers who

it

is noted

that

the

live within 1 km distance from the two factories, have got

the compensation up to 100.000.000TL in certain years. But to prevent the damage caused by these plants to the environment, a

457

sulphuric acid plant i s almost completed. The attempts to establish a pollution monitoring network throughout Turkey

are being

continued in order to prevent pollution. For the time

being there are 16 monitoring stations in Ankara today where the pollution is very high and 14 in other cities. As a part of the pollution combatting strategy, energy conservation measures play

an important role for the countries with limited sources of

energy for this purpose. To

decrease

fuel consumption by

adequate

insulation of buildings an amendment was made in the Building Regulation and heat insulations were made

compulsory for all new buildings after

January 1983. Finally, we think that conservation and improvement of environment can only be achieved through close international cooperation and therefore this Conference should be a great contribution to provide political support in this respect.

the necessary

T. Schneider (Editor)/Acidificationand its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

459

A I R POLLUTION CONTROL POLICY AND RESEARCH I N AUSTRIA R. ORTHOFER A u s t r i a n Research Center, A-2444 S e i b e r s d o r f ( A u s t r i a ) Present Address: Federal M i n i s t e r y o f H e a l t h and Environment, A-1031 Vienna ( A u s t r i a )

ABSTRACT The main goal o f t h e A u s t r i a n p o l l u t i o n c o n t r o l p o l i c y i s t h e r e d u c t i o n o f a l l r e l e v a n t emissions t o t h e lowest p o s s i b l e l e v e l which can be reached by advanced technologies. Generally, a i r q u a l i t y i s t r i e d t o be improved by Emission Standards r a t h e r than Ambient A i r Q u a l i t y Standards. The emissions o f SO have been reduced by almost 50 % from 1980 t o 1984. U n t i l 1995 a 70 % redu&ion based on t h e 1980 emissions i s p r o j e c t e d . Measures t o reduce NO have been taken o n l y r e c e n t l y and have n o t y e t shown considerable e f f e c t . 30 % r e d u c t i o n i s t h e t a r g e t f o r 1995. The A u s t r i a n government considers s t r i n g e n t emission standards f o r motor v e h i c l e s t h e most e f f e c t i v e measures t o reduce NO , hydrocarbons and carbon monoxide. Therefore, from January 1987 ( f o r l a r g e c a f s ) and from 1988 ( f o r small c a r s ) t h e U.S. 1983 emissions standards f o r passenger c a r s a r e mandatory, which a t present can be reached o n l y w i t h c a t a l y t i c converters. The supply o f l e a d - f r e e gasoline a t a l l gas s t a t i o n s w i t h c o m p e t i t i v e p r i c e s has been r e g u l a t e d by law. Research i n t h e f i e l d o f a i r p o l l u t i o n e f f e c t s on t h e environment i n c l u d e s a program e s p e c i a l l y aimed a t t h e problems connected w i t h f o r e s t damages. I t i s funded w i t h about 120 Mio. A.S./yr, o f which 213 goes t o damage m o n i t o r i n g . INTRODUCTION The A u s t r i a n government i s very concerned about t h e present environmental p o l l u t i o n . I n r e s p e c t t o a i r p o l l u t i o n t h i s concern i s n o t o n l y about a c i d i f y i n g pollutants, but a l l a i r pollutants: SO2.

n i t r o g e n oxides, carbon monoxide, anthropogenic hydrocarbons, heavy metals

and l a s t b u t n o t l e a s t : i n t h e f u t u r e s u r e l y an emphasis w i l l be p u t on the problems connected w i t h t h e c o n t r o l l e d o r u n c o n t r o l l e d r e l e a s e o f r a d i a t i o n o r r a d i a t i o n e m i t t i n g isotopes. A u s t r i a considers a i r p o l l u t i o n as t h e main and primary source o f f o r e s t d e s t r u c t i o n and as a c o n t r i b u t i n g f a c t o r t o t h e p o l l u t i o n o f s o i l and water. With some l u c k as most o f t h e s o i l s and waters a r e w e l l b u f f e r e d , A u s t r i a has n o t had many problems w i t h t h e a c i d i f i c a t i o n o f lakes and streams l i k e some c o u n t r i e s i n Northern Europe. On t h e o t h e r hand t h e r e are g r e a t problems i n A u s t r i a w i t h t h e r a p i d growing

460 f o r e s t damages caused by a i r p o l l u t a n t s . A u s t r i a i s very r i c h i n f o r e s t s : about 30 % o f t h e A u s t r i a n s u r f a c e i s covered w i t h f o r e s t s . The l a s t annual survey i n 1985 showed about 1/3 o f t h e A u s t r i a n f o r e s t s w i t h v i s i b l e damage, 5 % o f t h e f o r e s t s seemed t o be h e a v i l y damaged. As v i s i b l e damage i s o n l y t h e l a s t s i g n o f the negative e f f e c t s o f a i r pollution, the f i g u r e o f affected forests i n Austria must be considered much h i g h e r . About h a l f o f t h e f o r e s t damage, e s p e c i a l l y i n mountain v a l l e y s , seems t o be caused by home-made a i r p o l l u t i o n , m o s t l y by SO2. But t h e o t h e r h a l f o f t h e damage i s caused by l o n g range t r a n s p o r t o f a i r p o l l u t a n t s from c o u n t r i e s i n the n o r t h and west o f A u s t r i a , m a i n l y by photooxidants i n combination w i t h SO2 and/or n i t r o g e n oxides. From t h e present knowledge i t i s concluded t h a t t h e damages a r e r e s u l t of d i r e c t damage by a i r p o l l u t i o n r a t h e r than by f o r e s t s o i l a c i d i f i c a t i o n , although considerable s o i l a c i d i f i c a t i o n can be n o t i c e d . Anyway, i n t h e l o n g term, s o i l a c i d i f i c a t i o n and s o i l t o x i f i c a t i o n i s considered t o be a l a r g e environmental t h r e a t . One o t h e r concern o f t h e A u s t r i a n government i s t o keep our atmosphere g e n e r a l l y c l e a n and s t a b l e . U n t i l now t h e r e i s n o t very much known about t h e atmospheric chemical and p h y s i c a l e q u i l i b r i u m and i t s e f f e c t s on t h e environment i n t h e l o n g term. Being aware t h a t environmental p o l l u t i o n - l i k e environmental media

-

knows

no n a t i o n a l borders, A u s t r i a considers i t s e l f among t h e most a c t i v e advocates of c l o s e m u l t i l a t e r a l and b i l a t e r a l co-operation i n t h e f i e l d o f environmental p r o t e c t i o n . This i s why A u s t r i a a l s o considers t h e ECE-Convention on Long-Range Transboundary A i r P o l l u t i o n as an i n s t r u m e n t o f major importance f o r i n t e r n a t i o n a l cooperation i n t h e f i e l d o f a i r management. A u s t r i a has signed t h e S02-Protocol t o t h i s Convention, which binds t h e C o n t r a c t i n g P a r t i e s t o reduce S02-emissions by 30 % t i l l 1993 on t h e b a s i s o f 1980. I n 1985 A u s t r i a had reached a l r e a d y a 50 % r e d u c t i o n o f S02-emissions compared t o 1980 and now a c t i v e l y promotes t h e speedy implementation of t h e n e g o t i a t i o n s concerning a NOx-Protocol of s i m i l a r form. NATIONAL POLICIES Strategy The main goal i s t o reduce t h e emissions o f a i r p o l l u t a n t s t o a l e v e l as low as p o s s i b l e which can be reached by advanced technologies, regardless o f t h e emissions being s c i e n t i f i c a l l y proved t o cause damage o r n o t . Generally, a i r q u a l i t y i s t r i e d t o be improved by Emission Standards r a t h e r than Ambient A i r Q u a l i t y Standards. For instance, i n t h e a i r p o l l u t i o n sector, a

46 1

new law i s t o become e f f e c t i v e soon, which demands, t h a t l a r g e p o l l u t i o n sources have t o c o n t i n u o u s l y adopt t h e l a t e s t a v a i l a b l e proven technology r e g a r d l e s s o f t h e emission standards allowed f o r t h e source i n t h e f i r s t place. These r e g u l a t i o n s a l s o apply on o l d p l a n t s .

E m i s s i on r e d u c t i o n s The f o l l o w i n g t a b l e shows t h e emission l e v e l s o f 1980 and 1984 ( d a t a i n 1000 tons/year): 1980

co C H

b

X Y

P a r t i c.

354

180

21 6

21 6

1070

1045

121

119

48

50

Pb

C

1984

0,9

0,3

as NO Data f o r combustion sources o n l y . Rough estimates f o r a l l anthropogenic C H -emissions i n 1985 range from 250.000 - 350.000 to&. Data f o r 1985

Sulfur dioxide.

A u s t r i a reduced SO2-emissions from about 354.000 t o / y r i n

1980 t o about 180.000 t o l y e a r i n 1984 o r almost 50 %. U n t i l 1995 a f u r t h e r r e d u c t i o n o f S02-emissions t o about 100.000 t o / y r i s p r o j e c t e d . This w i l l be a

70 % r e d u c t i o n from t h e 1980 f i g u r e s . This was achieved m a i n l y by f u e l s w i t c h i n g from heavy f u e l o i l t o n a t u r a l gas, by f u e l o i l d e s u l f u r i z a t i o n and by f l u e gas d e s u l f u r i z a t i o n i n most o f t h e thermal power p l a n t s . S u l f u r c o n t e n t standards i n f u e l o i l have been lowered between 1982 and 1984: f o r heating o i l

from 0,5 % t o 0,3 %

for l i g h t fuel o i l

from 1,5 % t o 0,5 %

f o r medium f u e l o i l

from 2,5 % t o 1,0 %

f o r heavy f u e l o i l

from 3,5 % t o 2,0 %

A f u r t h e r l o w e r i n g o f these standards i s c u r r e n t l y under review, subject t o t e c h n i c a l f e a s i b i l i t y . More than 20 % o f t h e heavy f u e l o i l o f f e r e d a t present has a s u l f u r c o n t e n t o f o n l y 1 %. N i t r o g e n oxides, hydrocarbons, carbon monoxide.

Measures t o reduce NOx have

been taken o n l y r e c e n t l y and have n o t y e t shown considerable e f f e c t . The present

462 t a r g e t i s a r e d u c t i o n o f a t l e a s t 30 56 by 1995.

By law a l l new thermal power s t a t i o n s have s t r i n g e n t emission l i m i t s and are f i t t e d w i t h S.elective C a t a l y t i c Reduction u n i t s . Some o l d p l a n t s are being r e t r o f i t t e d w i t h SCR-units, too. The A u s t r i a n Government considers s t r i n g e n t emission standards f o r motor v e h i c l e s t h e most e f f e c i v e measures t o reduce NOx,

hydrocarbons and carbon

monoxide. A remarkable r e d u c t i o n o f atmospheric p o l l u t a n t s w i l l be reached by a whole package o f measures: A l l d i e s e l - c a r s l i c e n s e d s i n c e January 1986 have t o comply w i t h t h e US-83 standards. A l l newly l i c e n s e d g a s o l i n e - d r i v e n c a r s above 1,5 1 w i l l have t o meet t h e s t r i c t US-83 standards as o f 1987 and a l l c a r s w i l l have t o meet these standards as o f 1988. A t present these standards can be reached o n l y by automobiles equipped w i t h c a t a l y t i c converters, which reduce emissions from automobiles f o r about 90 %. For t h e n e x t 10-15 years t h e r e w i l l be no a l t e r n a t i v e t o t h e c a t a l y t i c c o n v e r t e r , b u t every technology which f i t s t h e standards i s accepted. Diesel c a r s are n o t regarded as an a l t e r n a t i v e t o t h e automobile emission problem. With s u i t a b l e t e c h n i c a l s o l u t i o n s being developed, some s t r i n g e n t measures w i l l be set f o r diesel cars

too.

The supply o f l e a d - f r e e g a s o l i n e as t h e p r e r e q u i s i t e f o r t h e i n t r o d u c t i o n o f t h e c a t a l y t i c c o n v e r t e r s has been r e g u l a t e d by law i n 1985; as a r e s u l t , every gas s t a t i o n s u p p l i e s r e g u l a r l e a d - f r e e gasoline. To achieve c o m p e t i t i v e p r i c e s , t a x e s on g a s o l i n e have been s h i f t e d f r o m r e g u l a r unleaded t o premium leaded g a s o l i n e . So unleaded gas i s about 5 % cheaper than leaded gas. Emissions from a l l l i c e n s e d automobiles a r e s u b j e c t t o a y e a r l y c o n t r o l . As f a r as speed l i m i t s are concerned t h e o p i n i o n o f t h e A u s t r i a n goverment i s t o e n f o r c e t h e e x i s t i n g speed l i m i t s o f 100/130 km/h r a t h e r than imposing lower speed l i m i t s w i t h o n l y l i t t l e enforcement, although on t h e l e v e l o f l o c a l s t a t e government lower speed l i m i t s have been s e t .

RESEARCH A l o t o f research i s c a r r i e d o u t in t h e f i e l d o f a i r p o l l u t i o n e f f e c t s on the environment, b u t i t i s n o t l i t e r a l l y named as A c i d i f i c a t i o n Research. A u s t r i a n research covers a i r q u a l i t y and d e p o s i t i o n m o n i t o r i n g , i n t e r n a t i o n a l a i r p o l l u t a n t s t r a n s p o r t research programs (EMEP, EUROTRAC), basic research on atmospheric chemistry, s t u d i e s o f environmental and h e a l t h e f f e c t s o f a i r p o l l u t a n t s as w e l l as h a n d l i n g and e v a l u a t i o n o f environmental data. A s p e c i a l coordinated program which s t a r t e d i n 1984 i s aimed a t t h e problems o f t h e d y i n g f o r e s t s . It i s c a l l e d "The Research I n i t i a t i v e Against t h e 'Waldsterben-

'I.

463

This research program i s conducted by t h e 3 competent M i n i s t e r i e s : While t h e Federal M i n i s t e r y o f A g r i c u l t u r e and S i l v i c u l t u r e i s responsible f o r p r a c t i c a l themes l i k e damage m o n i t o r i n g o r t h e management o f a f f e c t e d f o r e s t s , t h e Federal M i n i s t e r y o f H e a l t h and Environment i s r e s p o n s i b l e f o r a i r m o n i t o r i n g i n c l u d i n g t h e EMEP-stations and t h e M i n i s t e r y o f Science and Research leads t h e s c i e n t i f i c program; t h i s i s m o s t l y d i r e c t e d a t t h e d i a g n o s i s and t h e a n a l y s i s o f t h e causes

o f t h e f o r e s t dieback. The whole program Mio. A.S./yr,

-

planned f o r 5 y e a r s

-

i s beeing funded w i t h about 120

most o f i t goes t o damage m o n i t o r i n g . S c i e n t i f i c research i s

funded w i t h about 30 Mio. A.S./yr.

I t i s c l e a r , t h a t a small c o u n t r y l i k e

A u s t r i a p e r s o n a l l y and f i n a n c i a l l y cannot conduct research i n a l l r e l e v a n t f i e l d s o f t h e f o r e s t damage science. Therefore t h e program concentrates on s p e c i f i c t o p i c s , which are t y p i c a l f o r t h e A u s t r i a n s i t u a t i o n o r which are n o t done somewhere e l s e . For t h i s reason t h e r e i s a h i g h i n t e r e s t t o c o o r d i n a t e research w i t h a l l i n t e r e s t e d and i n v o l v e d c o u n t r i e s so d u p l i c a t e d e f f o r t c o u l d be minimized. A s a research s t r a t e g y a l l research work i s concentrated on o n l y a very few

s i t e s . On 3 research l o c a t i o n s (one i n t h e northwest o f A u s t r i a near t h e German and Czechoslovakian border; one i n a S02-loaded mountain v a l l e y ; one i n t h e e a s t e r n "Wienerwald") s c i e n t i s t s study a v e r y few t r e e s thoroughly from a m u l t i d i s c i p l i n a r y aspect. I n a d d i t i o n t o these s c i e n t i f i c research e f f o r t s a t e c h n i c a l research i n i t i a t i v e w i l l be s t a r t e d i n 1986 w i t h t h e aim o f t h e development o f new emission c o n t r o l technologies. The f u n d i n g w i l l be about 200 Mio A.S. years.

for 5

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V.. Amsterdam - Printed in The Netherlands

LIECHTENSTEIN

465

Dr. Felix Nascher

Policies concerning acidification and national research programmes related to those policies Healthy forests are of existential importance for the survival of the population in the alpine country of Liechtenstein. That is why, within the frame of the current "Healthy Forest" (GEWA) programme o f investigation, extending over the years 1984 - 1990 the Government instructed the State Forestry Office in November

-

1983,

to keep a continuous record o f the effects o f air pollution on the state of health of the entire Liechtenstein forest, to evaluate these records and to state in advance whether there is a possibility increased danger of infestation by secondary pests;

-

of an

to analyse the significance of air pollution with respect to damage to the forest and to propose measures for reducing air pollution which would be effective as far as the forest is concerned;

-

t o investigate the condition and the changes in condition of the forest

soil, to evaluate these changes and to create the preconditions, related to the knowledge available, f o r the specialized surface protection of severely damaged forest sites. Since that time in a 10-point-programme the following data are collected in order to determine the extent and progress o f the damage: 1)

-

At commune level yearly data collecting by questionnaires concerning the forest damage situation by the Local Forest Authority;

2)

-

six-monthly damage response of individually marked trees in permanently observed surfaces in order objectively to evaluate the development and the rate o f advance of phytophathological events;

3)

-

periodic survey of forest damage in a country-wide, permanent random sample network with simultaneous survey of forest inventory data;

466 4)

-

periodic country-wide survey and evaluation of forest damage with infra-red colour photographs taken from the air in the scale

1 5)

-

: 10'000;

yearly survey and evaluation of forest damage on a selected area in order objectively to know the development of the forest damage with infra-red photographs taken from the air in the scale 1 : 3 ' 0 0 0 ;

6)

-

annually recording of the sulphur content of spruce needles since 1 9 7 3 , by means of a country-wide, permanent network of random tests;

7)

-

periodic soil analysis by means of a country-wide, permanent network of random tests (macroelements, essential micronutrients, trace and heavy metals (essential and toxic elements), etc., analysed in at least two extracts: water soluble and exchangeable); physical parameters; organic matter; availability of nutrients. Analysis of residues after use of herbicides and pesticides;

8 ) - measurement o f air pollution by means of a permanent measuring station

and a mobile measuring station in selected areas

o f the Liechtenstein forest, always during the course of a year. Besides meteorological data the following values are recorded: SO2, NO, NO2, CO, 03, suspended dust (total dust quantity - PB lead and Cd) also deposited dust (total dust quantity Pb and Ed). The pH value, ammonium, K , Ca and Mg as cations, sulphate, nitrate and chloride as anions are determined from acid rain;

-

9)

-

periodical examination of the livers and kidneys of mice, hare, roe deer and chamois with reference to Pb and Cd;

10)

-

various other investigations.

The results accumulated so far within the scope of this programme caused a number of countermeasures to be introduced, with shortterm o r lono-term effects. And although they are similar to the ones, my friend from Switzerland has spoken about, I repeat some of them again, because it is so refreshing to hear about progress in the environmental field:

467

-

The putting into force of a new clean-air law in Parliament, in the autumn of 1985, as an effective weapon in the fight against air pollution on a broad basis. The limit values going to be determined by ordinance, for emissions as well as f o r immissions, aim to be the strictest standards valid in Europe;

-

the prohibition since the 1.1.1986, o f the u s e of "heavy" and "medium" grade oil for heating o r industrial purposes:The sulfur content of the oil used now has to be below 0 . 3 %, s o SO -emissions have been reduced 2

more than 50 X in a few years;

-

the installation of a country-wide supply grid for natural gas, for the larger business and industrial premises by the end of 1986, in the first instance ;

-

-

the complete tax exemption f o r all motor vehicles equipped with three-way catalytic converters till 1989; the availability

of

lead-free petrol at more than 95 % of all petrol

stations at a comparably lower price;

-

the general introduction of speed limits of 50 km/h in built up areas and 80 km/h elsewhere from 1.1.1985;

-

the introduction and application o f U S 8 3 exhaust-gas standards by the for private cars and by the 1.10.1988 f o r light commercial vehicles (delivery vans, small buses);

1.10.1987

-

-

the ratification of the ECE-UNO Agreement dated the 13th November, 1979, concerning long-range transfrontier air pollution and within the frame of this Agreement; from autumn 1986 participation in the programme concerned with co-operation in the measurement and evaluation of the long-range transmission of air polluting substances in Europe (EMEP), also

-

the signing and ratification of the declaration of intent dated the 9th July, 1985, in Helsinki, concerning the reduction in the emission of sulphur by 30 5 (related to 1980) by 1993/95.

468

-

The obligatory annual carrying out of exhaust-gas checks since 1986;

-

the considerable reduction in public transport fares and the availability of cheap season tickets;

-

the holding of two motor-vehicle-free sundays in April and September, 1985 in order to enlarge the public awareness for air pollution problems;

- the information and advice to the public;

-

the promotion of effective refuse-disposal planning (sorting/composting) in order to minimize waste-combustions problems;

-

the introduction of exhaust-gas regulations for heavy vehicles (lorries, articulated lorries, coaches and caravans) and also introduction of stricter standards for motorcycles and mopeds are visualized for the 1.10.1987 in a 1st stage.

Whereas, owing to the introduction of a number of measures, the emission of SO has declined noticeably since the beginning of the nineteen-eighties, 2

the concentrations of NO and hydrocarbons remain unchanged. Accordingly, ozone's outstanding significance as an air pollutant at the present time will increase. Government measures must therefore be aimed primarily towards the drastic reduction of NOx and hydrocarbon emissions. As we try to do our homework as well and as fast as possible as regards taking countermeasures against air pollution, we expect the same from all

the other countries. Air is our common resourceand that means, that nobody can claim justification to live at the costs o f his neighbour o r the future generations. And with cordial thanks to the hosting country for having organized this important conference I like to come to an end by saying that the common ressource I' air" needs common action. And as the state of air pollution presents itself now, immediate and incisive action is necessary.

471

T. Schneider (Editor)/Acidification and its Policy Implications Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands

FINAL REMARKS

OR. P. WINSEMIUS M i n i s t e r o f Housing, Physical Planning and Environment

M r . Chairman, esteemed delegates, l a d i e s and gentlemen, I n Munich, when I o f f e r e d t h e Netherlands as h o s t o f t h e f i r s t conference, I was aware t h a t I was t a k i n g on a b i g j o b , A t t h a t time, i t was n o t p o s s i b l e t o oversee whether a Conference where research was discussed i n t h e presence o f p o l i c y makers c o u l d d e l i v e r what we expected. Then, a t t h e s t a r t o f t h i s Conference,

I posed a number o f questions. The answers t o those questions

- o r t h e l a c k o f answers- w i l l show what t h e o u t p u t o f t h i s Conference i s . The e x t e n t t o which p o l i c y and t h e development o f p o l i c y have been f u r t h e r strengthened and whether o r n o t p o l i c y i s moving i n t h e r i g h t d i r e c t i o n , are o f primary importance t o me and t o t h e Executive Body. More than twenty speakers

have presented an overview o f t h e s t a t e - o f -

t h e - a r t i n t h e v a r i o u s t o p i c s . I t i s c l e a r t h a t i n s i g h t s converge regarding t h e d i f f e r e n t aspects o f a c i d i f i c a t i o n . Only very s u b s t a n t i a l r e d u c t i o n s i n a i r p o l l u t i o n can s t o p i n j u r y t o f o r e s t s , lakes, monuments, archives, and

SO

forth. The need t o strenghten i n t e r n a t i o n a l c o o r d i n a t i o n o f research has come c l e a r l y t o t h e f o r e d u r i n g t h e Conference. Several examples o f b i l a t e r a l and international

research have a l s o been presented.

F u r t h e r , i t has become i s a need f o r q u a n t i f i e d estimates o f f i n a n c i a l damage i n apparent t h a t t h e r e a d d i t i o n t o more i n f o r m a t i o n about t h e e x t e n t o f the various phenomena.

As f a r as t h e c o n t e n t o f t h e research i s concerned, more a t t e n t i o n i s hydrocarbons, and ozone, i n a d d i t i o n t o SO2, and f o r t h e complex processes i n t h e s o i l , whether o r n o t i n t h e framework o f t h e s o - c a l l e d ' i n t e g r a l m o n i t o r i n g ' .

emerging f o r the s i g n i f i c a n c e o f NO,

A d i r e c t i o n i n t h e research t h a t i s developing s t r o n g l y -and t h a t can certainly contribute effectively-

i s t h e use o f models.

Q u a n t i f y i n g and

47 2 s i m u l a t i n g t h e a c i d i f i c a t i o n phenomenon w i l l p r o v i d e i n s i g h t i n t o whether o r n o t we a r e headed i n t h e r i g h t d i r e c t i o n w i t h i n t e r n a t i o n a l measures. With these p o i n t s , t h e Conference has provided i n f o r m a t i o n about how and i n what d i r e c t i o n research i s developing. More c e r t a i n t y about t h e r e l a t i o n s h i p between cause and e f f e c t has been o b t a i n e d a t t h i s Conference.

Several speakers have r e p o r t e d t h a t ,

where

emission l i m i t i n g measures have reduced t h e sulphur burden i n some regions i n Canada and Sweden, recovery o f f o r e s t s and lakes has a l s o indeed taken place, be i t t o a l i m i t e d degree. I t can be hoped t h a t f u r t h e r r e d u c t i o n s w i l l also produce t h e d e s i r e d f u r t h e r improvements. sign,

This i s i n i t s e l f an encouraging

i n d i c a t i n g t h a t progress i n recovery i n a f a i r l y s h o r t time i s n o t

impossible. A c t u a l recovery i s r e l a t i v e l y so small and i n s i g n i f i c a n t n e x t t o t h e f u r t h e r damage t o f o r e s t s , lakes, e t c . elsewhere, t h a t we cannot y e t f e e l t o o encouraged about it. The r o l e o f NO,

b u t e s p e c i a l l y o f ozone and photo-oxidants,

emphasized by v a r i o u s speakers. n o t s o l v e t h e problem.

It i s c l e a r t h a t o n l y c o n t r o l l i n g SO2 w i l l

It i s evident t h a t

a t t e n t i o n f o r NOx and hydrocarbons.

U.S.S.R.

has been

there w i l l

I n addition,

a l s o have t o be

o u r colleagues from the

have a l s o requested a t t e n t i o n f o r the problem of p e s t i c i d e s as an

i m p o r t a n t element i n environmental p o l l u t i o n . We have a l s o found some answers t o t h e q u e s t i o n o f t h e tempo w i t h which the effects strike.

They a r e n o t a b s o l u t e l y accurate,

b u t i t i s nevertheless

c l e a r t h a t t h e tempo i s f a s t and probably f a s t e r than t h e tempo w i t h which we a r e c u r r e n t l y reducing a c i d i f i c a t i o n .

T h i s i s e v i d e n t from t h e e x t e n t o f

e f f e c t s on f o r e s t s , water, d r i n k i n g water, The

c u l t u r a l p r o p e r t y and m a t e r i a l s .

I I A S A model development i s a l s o an i n t e r e s t i n g i n d i c a t i o n .

With the

S02-reduction c u r r e n t l y intended by t h e c o u n t r i e s -on average, a 25 percent r e d u c t i o n i n Europe- a c i d i f i c a t i o n of v u l n e r a b l e s o i l s w i l l s t i l l continue i n l a r g e p a r t s of Europe. That means t h a t f u r t h e r SO2 r e d u c t i o n i s necessary. Therefore, we w i l l have t o increase o u r tempo. Few c o n c r e t e l i m i t s have been marked o u t f o r t h e l e v e l s o f these substances a t which p o s s i b l e e f f e c t s appear

and t h e l e v e l s t h a t a r e acceptable. Figures

have been named f o r n i t r o g e n t h a t a r e of t h e same o r d e r o f magnitude as those mentioned

i n m.y

opening address.

T h i s agreement i s ,

incidentally,

not

s u r p r i s i n g , s i n c e a Dutch speaker was involved. B u t I s t i l l want t o emphasize

473 t h a t i t i s very important t h a t these l i m i t s be indicated, determine how f a r we need t o go w i t h c o n t r o l .

so t h a t we can

I advocate focussing more

research on t h i s issue. The Canadian and Swedish i n f o r m a t i o n already mentioned shows t h a t recovery o f damaged ecosystems i s p o s s i b l e i n some cases. As I s a i d before, SO2 w i l l have t o be reduced more than i t i s now and NOx and hydrocarbons w i l l a l s o have t o be tackled. As f a r as our c u l t u r a l monuments are concerned, we have t o s t a t e t h a t no r e a l recovery i s possible. Restoration i s p o s s i b l e t o a c e r t a i n degree,

b u t i n v o l v e s h i g h costs.

A delayed e f f e c t a l s o occurs i n

c u l t u r a l monuments, however, so t h a t t h e r e i s already a l o t o f f u t u r e damage s t o r e d i n t h e monuments. Temporary management measures a r e c e r t a i n l y desirable, b u t they c o s t a l o t o f money and are n o t always possible. During the Conference, has come t o t h e f o r e t h a t

'liming'

f o r example, i t

o f a c i d i f i e d lakes does n o t o f f e r a

general s o l u t i o n . Aluminium t o x i c i t y i s t h e worst e f f e c t i n a c i d i f i e d surface waters. Liming o f some 4000 Swedish lakes proved t o be successful, b u t has t o be repeated every t h r e e t o f i v e years. Ifaluminium concentrations are high, l i m i n g does n o t r e s u l t i n b e t t e r c o n d i t i o n s f o r f i s h . The damage t o a g r i c u l t u r e from a i r p o l l u t i o n t h a t I mentioned a t the s t a r t o f the Conference, i s confirmed by numbers from the U.S. Even higher damage percentages -namely 10 percent- are being mentioned and damage o f several b i l l i o n s o f d o l l a r s p e r year. Damage is a l s o reported by t h e Soviet Union. I n c e r t a i n cases, even much higher damage percentages f o r a g r i c u l t u r a l crops have been reported. Models do n o t solve our problem. They can c l a r i f y the problem and a l s o play a r o l e i n q u a n t i f y i n g t h e u n c e r t a i n t y . The development o f t h e a c i d i f i c a t i o n model by I I A S A , based on the EMEP-model adhered t o by Eastern and Western Europe together, has given us an idea o f the s i g n i f i c a n c e o f t h e SO2 c o n t r o l c u r r e n t l y intended by the countries.

I t i s u s e f u l t o have t h i s i n d i c a t i o n

from t h e model, even though i t i s bad news. It i s possible t h a t t h e development launched by PHOXA (West Germany and the Netherlands) can provide s i m i l a r i n f o r m a t i o n about NOx, ozone and hydrocarbons i n t h e f u t u r e . When I see these answers t o t h e questions I posed, Conference has been c o s t - e f f e c t i v e

,

I think that this

even though n o t everything has been

answered conclusively. This, together w i t h the u s e f u l contact between science

474 and p o l i c y , makes me b e l i e v e t h a t a r e p e t i t i o n o f t h i s Conference once every two o r t h r e e years can p r o v i d e meaningful support f o r t h e Executive Body. We need i n f o r m a t i o n t o prevent experimenting w i t h nature. On t h a t p o i n t I agree h e a r t i l y w i t h Professor Kuenen.

J u s t as I agree w i t h him concerning

s a f e t y f a c t o r s . An engineer c a l c u l a t e s t h e necessary strenghth o f a b r i d g e and then b u i l d s i n a s a f e t y f a c t o r o f t h r e e t o f i v e . We a l s o t r y t o make t h a t c a l c u l a t i o n f o r t h e environment,

b u t use a s a f e t y f a c t o r l e s s than one

because more does n o t seem f e a s i b l e . I n c i d e n t a l l y , i n choosing Professor Kuenen t o be Chairman o f t h e Bureau, a very h i g h s a f e t y f a c t o r has been a p p l i e d t o t h i s Conference.

I am very

g r a t e f u l t o him f o r being w i l l i n g t o do t h i s . The Dutch p a r t i c i p a n t s were a1 ready f a m i l i a r w i t h Professor Kuenen's e x c e l l e n t l e a d e r s h i p , b u t now our f o r e i g n guests have a l s o become acqc;ainted w i t h i t . He has ensured t h a t the Bureau, i n good cooperation, a r r i v e d a t conclusions and recommendations w i t h which we can j o i n t l y go f u r t h e r i n t h e ECE.

475 NATIONAL DELEGATIONS Austria R. O r t h o f e r A u s t r i a n Research C e n t r e S e i b e r s d o r f 2444 SEIBERSDORF t e l . : (2254) 800 t e l e x : 014/353 Be1 g i um T.de R i j c k M i n i s t r y o f P u b l i c H e a l t h an Environment Vesal i u s Gebouw 1010 BRUSSELS t e l . : 02-2104872 t e l e x : 25768 mvgspf b H. Peperst r a e t e M i n i s t e r i e L e e f m i l i e u en M a a t s c h a p p e l i j k e Emancipatie W e t s t r a a t 56 1040 BRUSSELS t e l . : 32-2304925 Canada Mrs.J.Reid A t m o s p h e r i c Envi ronment S e r v i c e 4905 D u f f e r i n S t r e e t DOWNSV IEW Onta r io T.Brydges Atmospheric Environment S e r v i c e 4905 D u f f e r i n S t r e e t DOWNSVIEW O n t a r i o H.Martin Atmospheric Environment S e r v i c e 4905 D u f f e r i n S t r e e t DOWNSVIEW O n t a r i o Czechosl ova k i a

J .Mate r na lyskumny Ustav CS-255 01 AZBRASLVA S t r n a d y 167 t e i . : 42-547842-7

476 Denmark P. 6. Suh r M i n i s t ry o f Environment 29, Strandgade OK-1401 COPENHAGEN K t e l . : 45 1 57 83 10 t e l e x : 31209

J. Fenger

N a t i o n a l Agency of Environmental P r o t e c t i o n

OK-4000 ROSKILOE t e l . : 02 37 11 37 t e l e x : 43116

Mrs.M.Jensen N a t i o n a l Agency o f Environmental P r o t e c t i o n OQ, Strandgade DK-1401 COPENHAGEN K t e l . : 01-5783010 t e l e x : 31209 Federal Republic o f Germany G.Feldhaus Bundesministerium des Innern Graurheindorfer Strasse 198 D-5300 BONN 1 t e l . : 0228-681 4561 t e l e x : 886896 H.Herbsleb Bundesministerium f u r Ernahrung, L a n d w i r t s c h a f t und Forsten Rochurstrasse 1 0-5300 BONN 1 t e l . : 0228-5293880 t e l e x : 886844 H.D.Gregor Umwel tbundesamt B i smarckpl a t z 1 D-1000 BERLIN t e l . : 030-8903-534 6. Rami Bundesministerium fur Forschung und Technik Heinemann Strasse 2 0-5300 BONN 2 t e l . : 0228-59-3147 t e l e x : 885674 J.SchmBlling Umweltbundesamt B i smarckpl a t z 1 D-1000 BERLIN 33 t e l . : 030-8903-277

477 A.Tabat Bundesministerium fur W i r t s c h a f t BONN H. Vygen Bundesministerium des Innern Graurheindorfer Strasse 198 D-5300 BONN 1 t e l . : 0228-68i 3605 t e l e x : 886896 E.Weber Bundesministerium des lnnern Graurheindorfer Strasse 198 D-5300 BONN 1 t e l . : 0228-681 4193 t e l e x : 886896 Finland L. Tarast i M i n i s t r - y o f t h e Environment Box 306 00531 HELSINKI t e l . : 358-0-1605503 t e l e x : ymin s f 123717 A.Estlander M i n i s t r y o f t h e Environment Box 306

00531 HELSINKI

t e l . : 358-0-7726380 t e l e x : ymin s f 123717 G.Nordlund F i n n i s h Meteorological I n s t i t u t e P.O.Box 503 SF-00101 HELSINKI t e l . : 7581350 t e l e x : 124436 e f k l s f France J.M. Lecl use M i n i s t e r e de 1 'Envi ronnement 14, Boulevard du General L e c l e r c 92524 NEUILLY SUR SEINE CEDEX t e l : 47-58-12-123177 t e l e x : d e n v i r 620602 f

478 Hungary L. Szabo N a t i o n a l A u t h o r i t y f o r Environment and Nature Conservation V.Arany J.U. 25 OKTH BUDAPEST t e l : 327-579 t e l e x : 227607 o k t h h

.

Mrs.M.M.Denes Ministry o f Industry M a t i r o k u t j a 85 1024 BUDAPEST t e l . : 568-591 t e l e x : 226376 Italy F.Anfuso Ministero per 1'Ecologia Piazza Venezia 11 ROME t e l : 6786293

.

D. Camuff o C o n s i g l i o Nazionale d. Ricerche C.N.R., Corso S t a t i U n i t i 4 1-35020 PADOVA t e l : 491845375 t e l e x : 430302 c n r pd 1

.

.

L Se 1 1e r M i n i s t e r o d e l l a Santa Via L i s z t 34 ROME t e l : 5916941

.

A.Senni Ministero per 1 'Ecologia Piazza Venezia 11 ROME t e l : 6786293

.

I r e 1 and N.Cal1 an Department o f Environment Custom House DUBLIN 1 t e l : (01)-793377 t e l e x : 31014

.

479

.

E A. Ma r k e y Department of Environment Custom House DUBLIN 1 t e l : (01)-793377 t e l e x : 31014

.

Liechtenstein F.Nlscher Landesforstamt FL-9490 VADUZ t e l : 075166277 t e l e x : 889290

.

Luxembourg-

A. Schi 1t z A d m i n i s t r a t i o n des Eaux e t F o r 6 t s B.P. 411 LUXEMBOURG t e l . : 29354 Nether1 ands, The

..

P J Ver k e r k M i n i s t r y o f Housing, Physical Planning and Environment P.O.Box 450 2260 MB LEIDSCHENDAM t e l : 070-209370 t e l e x : 76684

.

B.J.M.van der Aart N a t i o n a l Council f o r A g r i c u l t u r a l Research P.0.Box 407 6700 AK WAGENINGEN t e l : 08370-19066

.

Mrs .A. A. He1mers N a t i o n a l Council f o r A g r i c u l t u r a l Research P.0.Box 407 6700 AK WAGENINGEN t e l : 08370-19066

.

M. Hoevers M i n i s t r y o f Economic A f f a i r s P.0.Box 20101 2500 EC DEN HAAG t e l . : 070-797159

480 Mrs.R.W.Hommes RMNO Alyda van Spangensingel 31 3054 C V ROTTERDAM t e l . : 010-184344

W. Kakebeeke M i n i s t r y o f Housing, Physical Planning and Environment P.O.Box 450 2260 MB LEIDSCHENOAM t e l . : 070-209370 t e l e x : 76684

.

J Ka rr e s C e n t r a l e Raad voor de M i l i e u h y g i e n e P.0.Box 5306 2280 HH RIJSWIJK t e l : 071-948948

.

D. P i etermaat M i n i s t r y o f Economic A f f a i r s P.0.Box 20101 2500 EC DEN HAAG t e l . : 070-797159 J.J.de R u i t e r M i n i s t r y o f A g r i c u l t u r e and F i s h e r i e s P.O.Box 20401 2500 EK DEN HAAG t e l . : 070-793911 A.van der Schaaf M i n i s t r y o f Foreign A f f a i r s P. 0.Box- 20061 2500 EB DEN HAAG t e l . : 070-484992 T.Schneider National I n s t i t u t e o f P u b l i c Health and Environmental Hygiene P.0.Box 1 3720 BA BILTHOVEN t e l . : 030-742970 t e l e x : 47215 R.C.J.Smit M i n i s t r y o f Transport and Pub1 i c Works P.O.Box 20901 2500 EX DEN HAAG t e l . : 070-747091 t e l e x : 32562 A. J. W i ggers M i n i s t r y o f A g r i c u l t u r e and F i s h e r i e s P.0.Box 20401 2500 EK DEN HAAG t e l . : 070-793911

481 B.C.J.Zoeteman N a t i o n a l I n s t i t u t e o f P u b l i c Health and Environmental Hygiene P.O.Box 1 3720 BA BILTHOVEN t e l : 030-742045 t e l e x : 47215

.

.

F Zui dema

National Council f o r A g r i c u l t u r a l Research P.0.Box 407 6700 AK WAGENINGEN t e l : 08370-19066

.

.

S Zwerve r M i n i s t r y o f Housing, Physical Planning and Environment P.0.Box 450 2260 MB LEIDSCHENDAM t e l . : 070-209370 t e l e x : 76684 Norway J.Thompson M i n i s t ry o f t h e Envi ronment P.0.Box 8013 Dep. 0030 OSLO 1 t e l . : (02)117510 t e l e x : 78990 P.M.Bakken M i n i s t r y o f t h e Environment P.0.Box 8013 Dep. 0030 OSLO 1 t e l . : (02)117674 t e l e x : 78990

.

B Her s t ad M i n i s t r y o f t h e Environment P.O.Box 8013 Dep. 0030 OSLO 1

tel.:(02)117784

t e l e x : 78990

B. Kvaeven S t a t e P o l l u t i o n Control A u t h o r i t y P.0.Box 8100 Dep. 0032 OSLO 1 t e l . : 2-229810 t e l e x : 76684 Mrs.S.Ofstad M i n i s t r y o f t h e Environment P.0.Box 8013 Dep. 0030 OSLO 1 t e l . : (02)117674 t e l e x : 78990

482 P. T a l l eraas M i n i s t r y o f t h e Environment P.O.Box 8013 Oep. 0030 OSLO 1 t e l . : (02)117627 t e l e x : 78990 Pol and Z.Harabin Environment P r o t e c t i o n and Water Management O f f i c e u l . Wspolna 30 00-930 WARSZAWA 2.Krzeminski Environment P r o t e c t i o n and Water Management O f f i c e u l . Wspolna 30 00-930 WARSZAWA B.Mol s k i B o t a n i c a l Garden P o l i s h Academy o f Sciences u l . Orezna 11 a 02 938 WARSZAWA t e l . : 427914/421525

Spaln R. Mont oya Inst.Naciona1 para l a Conservacion de l a Naturalesa (ICONA) Gran v i a de San F r a n s i s c o 35 28005 MADRID t e l . : 0034(1)2650012 R. P i cazo Min.Obrus MADR I0

P u b l i c a s y Urbanism0

Sweden L. BjBrk bom M i n i s t r y For F o r e i g n A f f a i r s Box 16121 S-10323 STOCKHOLM t e l . : 08-7866000 t e l e x : 10590 A.Boheman M i n i s t ry o f Agri c u l t u r e Drottninggatan 21 S-10333 STOCKHOLM t e l : 08-7631000 t e l e x : 15681

.

483 U.von Brflmssen N a t i o n a l Environment P r o t e c t i o n Board Box 1302 S-17125 SOLNA t e l : 08-981800 t e l e x : 11131

.

W .Di ckson

N a t i o n a l Environment P r o t e c t i o n Board Box 1302 S-17125 SOLNA t e l : 08-981800 t e l e x : 11131

.

P. Grennfel t The Swedish I n s t i t u t e f o r Water and A i r P o l l u t i o n Research ( I V L ) Box 21060 S-10031 STOCKHOLM t e l : 08-249680 t e l e x : 15581

.

J.Ni 1sson N a t i o n a l Environment P r o t e c t i o n Board Box 1302 S-17125 SOLNA t e l . : 08-981800 t e l e x : 11131

.

G Per s son N a t i o n a l Environment P r o t e c t i o n Board Box 1302 S-17125 SOLNA t e l : 08-981800 t e l e x : 11131

.

S w i t z e r 1and

C. L e u t e r t Bundesamt fur Umweltschutz 3003 BERN t e l : 31-619312

.

A.Clerc Bundesamt fur Umweltschutz 3003 BERN t e l : 31-619312

.

C.Tranchet Bundesamt fur Forstwesen und Landschaftsschutz Postfach 187 CH-3001 BERN t e l : 031/618074

.

484 Turkey Mrs. N.Bi nboga General D i r e c t o r a t e o f Environment A t a t u r k B u l v a r i 143 B a k a n l i k l a r ANKARA t e l : 174455142

.

K.Ceyl an General D i r e c t o r a t e o f Environment A t a t u r k B u l v a r i 143 B a k a n l i k l a r ANKARA t e l : 174455142

.

U n i t e d Kingdom A.Apl i n g Department o f t h e Environment 43, Marsham S t r e e t LONDON s w i p ~ P Y t e l . : 0 1 212 4172 t e l e x : 22221

R. But 1 in

Department o f t h e Environment Bui 1d . Res E s t WATFORD WD2 7JR t e l . : 0927 374040

. .

A.M. Hough Atomic Energy Research Est. Env.,Med. Sciences, Room 8364 AERE HARWELL, O x f o r d s h i r e O X 1 1 ORA t e l . : 0235 834621 t e l e x : 83135 G.Jenkins Department o f t h e Envi ronment 43, Marsham S t r e e t LONDON SWlP 3PY t e l . : 0 1 212 6679 t e l e x : 22221

F. L a s t

I n s t i t u t e o f T e r r e s t r i a l Ecology Bush E s t a t e , P e n i c u i k MIDLOTHIAN EH26 OQB t e l . : 031 445 4343 J.Moss Department o f Energy Thames House South M i 11 bank LONDON SW1 t e l . : 0 1 211 5830

485 M.Turnbul1 Department o f t h e Envi ronment 43, Marsham S t r e e t LONDON SWlP 3PY t e l . : 01 212 5880 t e l e x : 22221 R.Wi l s o n

Department o f t h e Environment 43, Marsham S t r e e t LONDON SWlP 3PY t e l . : 01 212 6161 t e l e x : 22221 USA R. E. Benedi ck

U.S.

Department o f S t a t e WASHINGTON D.C. 20003 t e l . : 202-6474000

3.L.Kulp

N a t i o n a l A c i d P r e c i p i t a t i o n Assessment Programme 722, Jackson Place NW WASHINGTON DC 20506 t e l . : 202-395-5772 E.R.Wi

11 iams

U.S. Department o f S t a t e

WASHINGTON D.C. 20003 t e l . : 202-6474000

D.L.Winters U.S. Department o f S t a t e WASHINGTON D.C. 20003 t e l : 202-6474000

.

USSR -

A.Pressman I n s t i t u t e f o r A p p l i e d Geophysics G1 ebovskaya S t r e e t 20b MOSCOW t e l : 2520808 t e l e x : 07230 mcs-e o f msce-e

.

S.N.Semenov S t a t e Committee f o r Hydrometeorology 12, P a v l i k Morozov S t r e e t MOSCOW 123376 t e l : 2520808 t e l e x : 07230 mcs-e

.

486 Yugoslavia V.Djuri c i c Hidrometeorological I n s t i t u t e o f Croatia Gric 3 41000 ZAGREB t e l . : 421-222 t e l e x : 21356 P.Karani k i c Embassy o f t h e S o c i a l s t F e d e r a l R e p u b l i c o f Yuogoslavia i n The N e t h e r l a n d s Groot H e r t o g i n n e l aan 30 2517 EG DEN HAAG t e l . : 070-632397 M. S1 a v n i c h Fed. Hyd romet e o r o l og ica 1 I n st it ut e B i r c a n i nova 6 1100 BEOGRAD t e l . : (011)646-555 t e l e x : y u shmz 12937 V.Sojat Hidrometeorological I n s t i t u t e o f Croatia Gric 3 41000 ZAGREB t e l : 421-222 t e l e x : 21356

.

United Nations

-

Economic Commission f o r Europe

K.A.Sah1 g r e n Executive Secretary U.N.-E.C.E. P a l a i s des N a t i o n s CH-1211 GENEVA 10 t e l . : 346011 t e l ex : 289696 C.Lopez Polo U. N. -E.C. E. P a l a i s des N a t i o n s CH-1211 GENEVA 10 t e l . : 346011 t e l e x : 289696 J.Marcks von Wllrtemberg U.N.-E.C.E. P a l a i s des N a t i o n s CH-1211 GENEVA 10 t e l . : 346011 t e l e x : 289696

487 INTERNATIONAL ORGANISATIONS HAVING AN OBSERVER STATUS I N MEETINGS OF THE UNITED NATIONS ECONOMIC COMMISSION FOR EUROPE

-

Commission o f t h e European Communities V.Mand1 R u e l a L o i 200 1049 BRUSSELS Be1g i um t e l : 2351111

.

F. Kremer Rue de l a Loi 86-4/48 8-1049 BRUSSELS Be1 g i um t e l . : 02-2356780 t e l e x : comeu b 21877 Organisation f o r Economic Cooperation and Development P.Lieben 2, Rue AndrC Pascal 75775 P A R I S Cedex 16 France t e l : 45027628 t e l e x : 620160 ocde p a r i s

.

U n i t e d Nations Environmental Programme A. Ren1und Regional O f f i c e f o r Europe GENEVA Switzerland t e l e x : 2887 unep ch U n i t e d Nations I n d u s t r y Development Organisation Mr.Ciuca P.0.Box 300 A1400 VIENNA Austria t e l : 26313622 t e l e x : 135612

.

.

M r Ga 1achi P.O.Box 300 A1400 VIENNA Austria t e l : 26313622 t e l e x : 135612

.

488

.

M r Soare P.O.Box 300 A1400 VIENNA Austria t e l : 26313622 t e l e x : 135612

.

United Nations UNIPEDE A.Clarke CEGB, Laud Hse.Room 320 20, Newgate Street LONDON EClA 7AX England t e l . : 01-634-6822 t e l e x : 883141 World Meteorological Organisation

H.van Dop KNM I P.0.Box 201 3730 AE DE BILT The Netherlands t e l . : 03-766911 t e l e x : 47096

489 L I S T OF PARTICIPANTS

B.J.M.van der Aart Nat.Counci1 f o r Agr.Research P.0.Box 407 6700 AK WAGENINGEN The N e t h e r l a n d s te1.:08370-19066

Mrs.A. Abad P u e r t o l a s ENDESA, Terueal Power P l a n t P r i n c i p e de Vergara 187 28002 MADRID Spai n t e l . : 91-4167012 t e l e x : 22917

F. Anfuso M i n i s t e r 0 p e r 1 'Ecologia P i a z z a Venezia 11 ROME Italy t e l : 6786293

A. A p l i n g Department o f t h e Environment 43, Marsham S t r e e t LONDON SWlP 3PY England t e l . : 0 1 212 4172 t e l e x : 22221

.

W.G. A r k e l N e t h e r l a n d s Energy Res.Found. P.0.Box 1 1755 ZG PETTEN The N e t h e r l a n d s t e l . : 02246-4336 t e l e x : 57211 r e a c p n l

ECN

C.A. Aronds Hoogovens IJmuiden, Env.Contr.Dep P.O.3ox 10000 1970 CA I J M U I D E N The N e t h e r l ands t e l : 02510-95232 t e l e x : 35211 hovs n l

.

Mrs.E. B a b b i t t Am.Acad. o f A r t s and Sciences 33 Lee S t r e e t 3 CAMBRIDGE MA 02139 USA t e l . : 617 492-8800

N.S. Baer New York U n i v e r s i t y 14 East 7 8 t h S t r e e t NEW YORK NY 10021 USA t e l . : 212-772-5800

P.M. Bakken M i n i s t r y o f t h e Environment P.0.Box 8013 Dep. 0030 OSLO 1 Norway t e l . : (02)117674 t e l e x : 78990

Mrs.A. B a l l e s t r e m Kunst en Wetenschap P.0.Box 5132 1007 AC AMSTERDAM The N e t h e r l ands

J. B a r r o s o

C. B a t i s s e - B a z i n Les Amies de l a T e r r e 7, Rue de l a C a v a l e r r e 75015 P A R I S France

B. Beckers

R.E.

D i reccao-Geral da Qua1idade Amb. Rua do Seculo 51-3 1 200 LISBON Portugal t e l . : 362751 t e l e x : 13322 dgambl p LISEC B O K R I J K 8-3600 GENK Be1 g i um t e l : 011/362791

.

Benedick

US Department of S t a t e

WASHINGTON OC 20003 USA t e l : 202-6474000

.

490

J .Bervaes

L. Bergman Stockholm School o f Economics Box 6501 S-11383 STOCKHOLM Sweden t e l . : 08-7360120

Zandstraat 9 5301 BT ZALTBOMMEL The Netherlands t e l : 04180-14493

U. Bieder Uni v e r s i t a t S t u t t g a r t 0-7000 STUTTGART 80 FRG t e l : 0711/6852388 t e l e x : 07255445

Binboga General D i r e c t o r a t e o f Envirnm. A t a t u r k B u l v a r i 143 Bakanl ik l a r ANKARA Turkey t e l . : 17 44 55/42 Mr5.N.

.

K. Bishop Uni v .of Cambridge ,Dep. Downing P1ace CAMBRIDGE CB2 3EN England t e l : 223-64416

.

o f Geogr.

. H. Blom N .V .KEMA P.O.Box 9035

6800 ET ARNHEM The Netherlands t e l : 085-562585 t e l e x : 45016 kema n l

.

W. Bleuten R i jksuniv.Utrecht ,Fysische Geogr. P.O;BOX 80.115 3508 TC UTRECHT The Netherlands t e l . : 030-532780 A.H. Blommers Geosens B.V. P.O.Box 12067 3004 GB ROTTERDAM The Netherlands t e l . : 010-378188 t e l e x : 25138 geo n l

B. Boehlen

A. Boheman Min.of A g r i c u l t u r e Drottninggatan 21 S-10333 STOCKHOLM Svreden t e l . : 08-7631000 t e l e x : 15681

L. Bjbrkbom Foreign A f f a i r s Box 16121 S-10323 STOCKHOLM Sweden t e l . : 08-7866000 t e l e x : 10590

M. Bovenkerk

N.van Breemen Agricultural University P.0.Box 37 6700 AA WAGENINGEN The Nether1ands t e l . : 08370-10930

A.H.M. Bresser Nat. I n s t .of Pub1 .H.and P.O.Box 1 3720 BA BILTHOVEN The Netherlands t e l . : (0)30-743108 t e l e x : 47215 r i v m n l

Bundesamt f.Lhnweltschutz 3003 BERN Switzerland t e l . : 31-619312

M i n.of

M i n .of Housi ng,Phys. P1 .and Env. P.0.Box 450 2260 MB LEIDSCHENDAM The Netherlands t e l . : 070-209367

Env.Hyg.

491

A. Broek P r o v i n c i a l Water A u t h o r i t i e s G a l i l e i l a a n 15 UTRECHT The Netherlands t e l . : 030-524111 t e l e x : 70306

U.von Brbmssen Nat.Environmenta1 Protec. Board Box 1302 S-17125 SOLNA Sweden t e l . : 08-981800 t e l e x : 11131

K. Brown C.E.G.B. Kel v i n Avenue LEATHERHEAD, Surrey KT22 7SE United Kingdom t e l . : (0)372 37488 t e l e x : 917388

N.A.J.H.C. Brllll Province o f Limburg Parkweg 32 6212 XN MAASTRICHT The Netherlands t e l . : 043-897604

T. Brydges Atmospheric Env.Service 4905 D u f f e r i n S t r e e t DOWNSV I EW Onta r i o Canada

P. B u i l t j e s MT-TNO Dep.of F l u i d Dynamics P.O.Box 342 7300 AH APELDOORN The Nether1 ands t e l . : 055-773344

J. Burgers

D.P. Burns USDA Forest Service 370, Breed Road BROOMALL Pennsylvania 19008 USA t e l . : 215-461-3008

R. B u t l i n Department o f Envi ronment B u i l d . Res. Est. WATFORD WO2 7JR England t e l . : 0927 374040

Mrs.L. B u t t e r w i c k Environmental Res.Limited 106, Gloucester Place LONDON England t e l . : 01.486.1211 t e l e x : 296359 e r l g

N. C a l l a n Department o f t h e Environment Custom House DUBLIN 1 I r e 1 and t e l . : (01)793377 t e l e x : 31014

0. Camuffo C o n s i g l i o Nazionale d. Ricerche C.N.R., Corso S t a t i U n i t i 4 1-35020 PADOVA Italy t e l . : 49/845375 t e l e x : 430302 c n r pd 1

Mrs.A. Cervera ASINEL Apartado 233 MOSTELOS (Madrid) Spain t e l . : 91-616 00 18 t e l e x : 48476

K. Ceylan General D i r e c t o r a t e o f Envi ronm. A t a t u r k B u l v a r i 143 B a k a n l i k l a r ANKARA Turkey t e l . : 18 64 93

Openbaar Lichaam Rijnmond P.0.Box 23073 3001 KB ROTTERDAM The Netherlands t e l . : 010-111320 t e l e x : 21121

492 M. Chadwick

B e i j e r Inst., Univ. o f York Heslington YORK Y O 1 5DD U n i t e d Kingdom t e l . : (904)59861 t e l e x : 57933 y o r k u l

R. C h a r t i e r U n i v e r s i t y o f Montreal R.R.l Laurel C.P. 141 (CTEE A r g e n t e u i l ) P.Quebec Canada JOT 1 Y O t e l : (514)343-7620

.

M r . Ciuca UNIDO P.0.Box 300 A1400 VIENNA Austria t e l . : 26313622 t e l e x : 135612

A. Clarke UNIPEDE 20 Newgate S t r e e t LONDON E C l A 7AX England t e l . : 01-634-6822 t e l e x : 883141

A. C l e r c Bundesamt fllr Umweltschutz 30003 BERN Switzerland t e l . : 31-619312

M.J. Cooke N a t i o n a l Coal Board Stoke Orchard CHELTENHAM Clos. GL52 4RZ England t e l . : (0242.67)3361 t e l e x : 43568 cbcre g

P. Cortes RBL "De Dorschkamp" P.O.Box 23 6700 AA WAGENINGEN The Netherlands t e l . : 08370-95311

H. Cortes S o r i a ENDESA, Envi ronment Department P r i n c i p e de Vergara, 187 28002 MADRID Spain t e l . : 91-4167012 t e l e x : 22917

A. Crane C.E.G.B. K e l v i n Avenue LEATHERHEAD, Surrey KT22 7SE U n i t e d Kingdom t e l . : (0)372 37488 t e l e x : 917388

H.L.M. Defoer Rijksm. h e t Catharijneconvent Nieuwe Gracht 63 3512 LG UTRECHT The Netherlands

Mrs.M.M. Denes Ministry o f Industry M a r t i r o k u t j a 85 1024 BUDAPEST Hun ga ry t e l : 568-591 t e l e x : 225376

W. Dickson Nat.Environmenta1 Protec. Board Box 1302 S-17125 SOLNA Sweden t e l : 08-981800 t e l e x : 11131

V. D j u r i c i c Hidromet. I n s t . o f C r o a t i a Gric 3 41000 ZAGREB Yugoslavia t e l . : 421-222 t e l e x : y u meteor 21356

W.van Doorn Oude Singe1 58 2312 RC LEIDEN The Nether1 ands t e l . : 071-122506

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493

J. Duysens

H.van Dop KNM I P.O.Box 201 3730 AE DE BILT The Netherlands t e l : 31-30-766911 t e l e x : 47096

IWACO P.0.Box 183 3000 AD ROTTERDAM The Netherlands t e l . : 010-241519

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N.O.van Egmond Nat.Inst.of Pub1 .H.and P.O.Box 1 3720 BA BILTHOVEN The Netherlands t e l . : (0)30-742025 t e l e x : 47215 r i v b h

Env.Hyg.

A.J. Elshout N.V. KEMA P.0.Box 9035 6800 ET ARNHEM The Netherl ands t e l . : 085-562381 t e l e x : 45016 kema n l

R.van Erpers Royaards N.V. KEMA P.0.80~ 9035 6800 ET ARNHEM The Netherlands t e l . : 085-562591 t e l e x : 45016

F. Esteban ASINEL Apartado Postal 233 MOSTOLES (Madrid) Spain t e l . : 91-616 00 18 t e l e x : 48476

A.

Estlander M i n i s t r y of t h e Environment Box 306 00531 HELSINKI Finland t e l . : 358-0-7726380 t e l e x : ymin s t 123717

P. Evers RBL "De Dorschkamp" P.0.Box 23 6700 AA WAGENINGEN The Netherlands t e l . : 08370-95347

J.F. Feenstra Free Univ., 1nst.Environm.Studies P.0.Box 7161 1007 MC AMSTERDAM The Netherl ands t e l . : (0)30-5483824

G. Feldhaus Bundesministerium des Innern Graurheindorfer Strasse 198 D-5300 BONN 1 FRG t e l . : 0228-681 4561 t e l e x : 889896

J. Fenger Nat .Agency o f Env.Protection OK-4000 ROSKILDE Denmark t e l . : 02 37 11 37 t e l e x : 43116

Mrs.A. Fraenkel UN-ECE observer GENEVA Switzerland t e l . : 968266

A.J. Frantzen KNMI P.0.Box 201 3730 AE DE BILT The Netherl ands t e l : 030-766911

Mrs.M. Fuchs Bur.of Nat.Affai r s Wash.D.C. P.O.Box 204 3500 AE UTRECHT The Netherl ands t e l . : 030-716162

.

494

Mr. Galachi UNIDO P.0.Box 300 A1400 VIENNA Austria t e l . : 26313622 t e l e x : 135612

A.J. G i j s w i jt SISWO P. 0. Box 19079 1000 GB AMSTERDAM The Netherl ands t e l . : 020-240075

J.A.N. Goncalves E l e c t r i c i d a d e de Portugal Av. E.V.A. 55, Room 9.04 1700 LISBON P o r t uga 1 t e l . : 809519

H.D. Gregor Umweltbundesamt Bismarckplatz 1 D-1000 BERLIN FRG t e l . : (030)8903 534

P. G r e n n f e l t Swedish 1nst.Water and A i r P o l l . Box 21060 S-10031 STOCKHOLM Sweden t e l : 08-249680 t e l e x : 15581

R. Guderian U n i v e r s i t y o f Essen U n i v e r s i t a t s s t r . 15 0-4300 ESSEN FRG t e l : 0201/ 183-2976

F.A.M.de

Haan University De D r e i j e n 3 6703 BC WAGENINGEN The Netherl ands t e l . : 08370-82151

S. Hagvar Norwegian F o r e s t Research I n s t . 1432 AS-NLH Norway t e l : 02-949697

J.van Ham TNO P.0.Box 186 2600 A0 DELFT The Netherlands t e l . : (0)15-569330 t e l e x : 38071

J. Hansen S t i c h t i n g Europoort/Botlek Bel. ‘s-Gravel andseweg 37-374 3125 BK SCHIEDAM The Netherl ands t e l . : 010-371066

Z. Harabin Env.Prot.and Water Manag.Office u l Wspolna 30 00-930 WARSZAWA Pol and

Mrs.A.A. Helmers Nat. Council f o r Agr.Res. P.0.Box 407 6700 AK WAGENINGEN The Netherlands t e l . : 08370-19066

H. Herbsleb Bundesm.f.Ernahrung,Landw.Forsten Rochursst r. 1 D 5300 BONN 1 FRG t e l . : 0228-5293880 t e l e x : 886844

B. Herstad M i n i s t r y o f t h e Environment P.0.Box 8013 Dep. 0030 OSLO 1 Norway t e l . : (02)117784 t e l e x : 78990

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A q i cul t u r a l

.

.

.

495

5. H i g l e r

Mrs.T. Heyse Greenpeace Be1 g i um Waversesteenweg 335 1040 BRUSSELS Be1g i um t e l . : 02/6478765 t e l e x : 24182

R. I . N . P.0.Box 46 3956 ZR LEERSUM The Netherlands t e l . : 03434-52941

M. Hoevers

R.C. Hol R ijksarchiefdienst Pr.Wil lem Alexanderhof 20 2595 BE DEN HAAG The Netherlands

Mrs.R.W. Hommes Vice Chairman RMNO Alyda van Spangensingel 31 3054 C V ROTTERDAM The Netherl ands t e l . : 010-184344

L. H o r d i j k I IASA A-2361 LAXENBURG Aust r i a t e l . : 02236-71521512 t e l e x : 079137 i i a s a

A.M. Hough Atomic Energy Research Est. Env.,Med.Sciences, Room 8364 AERE HARWELL, O x f o r d s h i r e O X 1 1 ORA England t e l . : 0235 834621 t e l e x : 83135

J.L. Innes F o r e s t r y Commission o f G r . B r i t a i n A l i c e H o l t Lodge Wrecclesham, FARNHAM Surrey England t e l . : 0420-22255

W.P.M.F. Ivens R i jksuniv.Utrecht, P.O.Box 80.115 3508 TC UTRECHT The Netherlands t e l . : 030-532780

G. Jenkins Department o f t h e Environment 43, Marsham S t r e e t LONOON S W l P 3PY England t e l . : 01 212 6679 t e l e x : 22221

Min.of Economic A f f a i r s P.O.Box 20101 2500 EC DEN HAAG The Netherl ands t e l . : 070-797159

Fysiche Geogr.

Mrs.M. Jensen Nat.Agency o f Env.Protection S t randgade 29 DK-1401 COPENHAGEN K Denmark t e l . : 01-5783010 t e l e x : 31209

F. Kafka I C I Europa Ltd. Everslaan 45 3078 EVERBERG Be1g i um t e l . : 02/758.9479 t e l e x : 26151 i c i e v b b

V.

L. K a i r i u k s t i s II A S A A-2361 LAXENBURG Aus t r ia t e l . : (2236) 715210 t e l e x : 079137 i i a s a a

Kaftanov

I IASA

A-2361 LAXENBURG Austria t e l . : 02236-71521 t e l e x : 079137

496 S. K a j i h a r a Environment Agency, Govern.Japan 1-2-2 Kasumigaseki , Chiyoda-ku TOKYO 100 Japan t e l : 03-580-2169 t e l e x : jpnea j33855

W. Kakebeeke Min.of Housing,Phys.Pl. P.0.Box 450 2260 MB LEIDSCHENDAM The Netherl ands t e l . : (0)70-209367 t e l e x : 32362

P. K a r a n i k i c Embassy Yugoslavia Groot H e r t o g i nnel aan 30 2517 EG DEN HAAG The Netherlands t e l . : 070-632397

J. Karres

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V. Keizer Min.of Housing, Phys.Pl. P.O.Box 450 2260 MB LEIDSCHENDAM The Netherlands t e l . : 070-209367

and Env.

Centr.Raad voor de M i l i e u h y g i e n e P.0.Box 5306 2280 HH R I J S W I K The Netherlands t e l . : 071-948948 and Env.

G. Klaassen University P.O.Box 7161 1007 MC AMSTERDAM The Netherl ands t e l e x : 10399 i n f v u n l

E. K l a t t e European Environmental Bureau Rue V a n t i e r 29 8-1040 BRUSSELS Be1 g i um t e l . : (2)6470199 t e l e x : bee 62720

T.E. Korkman M i n i s t r y o f t h e Environment Strandgade 29 1401 COPENHAGEN Denmark tel 0 1 578310 t e l e x : 31209 m i l s o e dk

F. Kremer

G. Krug Cons.ECE, F a c u l t e Sciences Agron. 5800 GEMBLOUX Be1 g i um t e l : 081/612958

C EC Rue de l a L o i 86-4/48 8-1049 BRUSSELS Be1 g i um t e l . : 02-2356780 t e l e x : comeu b 21877

.

2. Krzeminski

Env.Prot.and Water Manag. O f f i c e u l . Wspolna 30 00-930 WARSZAWA Pol and J.L. Kulp Nat .Acid Prec.Assessment 722 Jackson Place, NW WASHINGTON DC 20506 USA t e l . : 202-395-5772

.:

Prog.

D.J. Kuenen RMNO Huis t e Landelaan 492 2283 VJ RIJSWIJK The Netherl ands t e l . : 070-948942 J. K u y l e n s t i e r n a B i j e r Inst., Univ.of Hesl i n g t o n YORK Y O 1 5DD United Kingdom t e l . : (904)59861 t e l e x : 57933 y o r k u l

York

497

J. Kuyper S h e l l , Env.Affairs Coord. H o f p l e i n 20 3032 AC ROTTERDAM The Netherlands t e l . : 010-696709 t e l e x : 21049

B. Kvaeven S t a t e P o l l .Control P.0.Box 8100 Dep. 0032 OSLO 1 Norway t e l . : (02)229810 t e l e x : 76684

R. L a i k i n B e i j e r I n s t . Univ.of Hesl i n g t o n YORK Y O 1 5DD U n i t e d Kingdom t e l . : (904)59861 t e l e x : 57933 y o r k u l

P. Lammers Friends of t h e Earth I n t . AIRPLAN P.0.Box 17179 1001 JD AMSTERDAM The Nether1 ands t e l : 020-838955

York

R. L a n t i n g TNO D i v i s i o n o f Techn.for P.O.Box 217 2600 AE DELFT The Netherlands t e l . : 015-569330 t e l e x : 38071 zptno n l

Authority

.

SOC.

Mrs.E. Lap Min. o f Economic A f f a i r s P.O.Box 20101 2500 EC DEN HAAG The Netherlands t e l . : 070-796420

F. Last

J.M. Lecluse M i n i s t e r e de 1 'Environnement 14, Boulevard du General Leclerc 92524 NEUILLY SUR SEINE CEDEX France t e l . : 47-58-12-123177 t e l e x : d e n v i r 620602 f

G. L e u t e r t Bundesamt fllr Umweltschutz 3003 BERN Switzerland t e l . : 31-619312

P. Lieben OECD Environment D i r e c t o r a t e 2, Rue Andre Pascal 75775 P A R I S Cedex 16 France t e l . : 45027628 t e l e x : 620160 ocde p a r i s

M. Long BP I n t e r n a t i o n a l Ltd. Moor Lane LONDON ECZY 9BU U n i t e d Kingdom t e l . : 01 920 3878 t e l e x : 888811

C. Lopez Polo U.N., E.C.E. P a l a i s des Nations CH-1211 GENEVA 10 Switzerland t e l . : 346011 t e l e x : 289696

Mrs.D. Mackenzy New S c i e n t i s t s Magazi ne 2, Rue de l a L o i 1213 GENEVA Switzerland t e l . : 41.22.932484

E. Mackinlay CEC, DG XI-A3 Rue de l a L o i 200 1049 BRUSSELS Be1 g i um t e l : 02/2350529 t e l e x : 21877 comeu b

I n s t . o f T e r r e s t r i a l Ecology Bush Estate, Penicuik MIDLOTHIAN EH26 OQB Scot1 and t e l . : 031 445 4343

.

498 Mrs.P. Mak Min.of Housing, Phys.Pl. P.O.Box 450 2260 MB LEIDSCHENDAM The Netherlands t e l . : 070-209367

and Env.

H.C. Mangan E l e c t r i c i t y Supply Board 27, Lower F i t z w i l l i a m S t r e e t DUBLIN 2 Ire1 and t e l . : (010)-765831 t e l e x : E I 30229

V. Mandl C EC Rue de l a Loi 200 1049 BRUSSELS Be1 g i um t e l . : 2351111

J. Marcks von WUrtemberg

-

U.N. E.C.E. P a l a i s des Nations CH-1211 GENEVA Sw it z e r 1and t e l . : 346011 t e l ex : 289696

E.A. Markey Department o f Environment Custom House DUBLIN 1 I r e 1 and t e l . : (01)793377 t e l e x : 31014

H. M a r t i n Atmospheric Env.Service 4905 D u f f e r i n S t r e e t DOW N S V l EW Onta r i o Canada

J. Materna Vyskumny Ustav CS-255 01 ZBRASLAV Strnady 167 Czechoslovakia t e l . : 42-547842-7

P. Mathy CEC 200, Rue de l a Loi 6-1049 BRUSSELS Be1 gium tel 02/235.81.60 t e l e x : 21877 comeu b

A. van de Meer M i n.of A g r i c u l t u r e and F i s h e r i e s P.0.Box 20401 2500 EK DE3N HAAG The Nether1 and t e l . : 070-792793

K. M e i j e r Min.of Housing, Phys.Pl. P.O.Box 450 2260 MB LEIDJCHENDAM The Netherlands t e l . : 070-209367

H. Meinl D o r n i e r System P.O.Box 1360 0-7990 FRIEDRICHSHAFEN FRG t e l : 0745/84308 t e l e x : 734209-0

Mrs.H.de Meyer U n i v e r s i t y o f Ghent S t r o p s t r a a t 140 8-9000 GENT Be1 g i um t e l : 02/2359512

Mrs.H. Meyer RMNO Huis t e Landelaan 492 2283 VJ RIJSWIJK The Netherlands t e l . : 070-948942

B. Molski

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.:

and Env.

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B o t a n i c a l Garden P o l i s h Acad.Sci. u l . Orezna 11 a 02 938 WARSZAWA Pol and t e l . : 427914/421525

439

Montoya ICONA Gran v i a de San F r a n s i s c o 35 28005 MADRID Spain t e l . : 0034(1)2650012 R.

K. Mortensen

Nordic Council o f M i n i s t e r s P.0.Box 6753, St.Olars p l a s s N-0130 OSLO 1 Norway t e l . : 02-111052 t e l e x : 19546 n o r d s n

J. Moss Department o f Energy Thames House South, M i l l b a n k LONDON SW1 England t e l . : 0 1 211 5830

K. M y k k e l t v e l d t

F. N l s c h e r

F. Nieuwstadt

.

KNMI P.O.Box 201 3730 AE DE BILT The N e t h e r l a n d s t e l . : 030-766911

Landesforstamt FL-9490 VADUZ Liechtenstein t e l . : 075/66277 t e l e x : 889290

J. N i l s s o n Nat.Environmenta1 Box 1302 S-17125 SOLNA Sweden t e l : 08-981800 t e l e x : 11131

Norwegian Ass.Hunters and A n g l e r s P.0.Box 94 1364 HVALSTAD Norway t e l : 02-783860

P r o t e c . Board

.

L.L.M.van Nispen t o t Sevenaer R i j k s d i e n t Monumentenzory B r o e d e r p l e i n 41 3703 CD ZEIST The N e t h e r l a n d s

G. Nordlund Finnish Met.Institute P.O.Box 503 SF-00101 HELSINKI Finland t e l . : 7581350 t e l e x : 124436 e f k l s f

Mrs.S. O f s t a d M i n i s t r y o f t h e Environment P.0.Box 8013 Dep. 0030 OSLO 1 Norway t e l . : 02-117674 t e l e x : 78990

Drs.P. Okken ECN/ESC P.O.Box 1 1755 ZG PETTEN The N e t h e r l a n d s t e l : 02246-4339

Tineke 01 ij Nat.Inst.of Pub1 .H. P.0.Box 1 3720 BA BILTHOVEN The N e t h e r l a n d s t e l : 030-742916 t e l e x : 472155

.

.

Orthofer A u s t r i a n Res.Centre 2444 SEIBERSDORF Austria t e l . : (2254) 800 t e l e x : 014/353

R.

and Env.Hyy.

H. P e p e r s t r a e t e

Sei b e r s d o r f

M i n . L e e f m i l i e u en Maat.Emancip. W e t s t r a a t 56 1040 BRUSSELS Be1 g i urn t e l : 32-2304925

.

500

.

G. Persson Nat En v i ronmenta 1 Protec. Board Box 1302 S-17125 SOLNA Sweden t e l : 08-981800 t e l e x : 11131

Mrs.R. P e t e r s Staatsbosbeheer P.0.Box 20020 3526 LA UTRECHT The N e t h e r l ands t e l . : 010-852344

R. P i c a z o dg Medio Amb., MADRID Spain

D. P i e t e r m a a t Min.of Econ A f f a i r s P.0.Box 20101 2500 EC DEN HAAG The N e t h e r l a n d s t e l : 070-797159

.

Min.Publicas/Urb.

.

A.C. Posthumus Res.Inst. f o r P l a n t P r o t e c t i o n P.0.Box 9060 6700 GW WAGENINGEN The N e t h e r l ands t e l . : 08370-19151

M. Przyszwa

A. Pressman 1 n s t . f o r A p p l i e d Geophysics Glebovskaya S t r e e t 20b

MOSCOW USSR t e l : 2520808 t e l e x : 07230 mcs-e

.

I.van d e r P u t t e

Gaz de France 361, Avenue du Pdt. W i l s o n 93210 La P l a i n e S a i n t - D e n i s France t e l : (1)48238415 t e l e x : 620334f gazdetn

Adv.bur.Bongaerts,Kuyper,Huisw.

B. Rami Bundesm. f u r Forsch. und Techn. Heinemann S t r a s s e 2 0-5300 BONN 2 FRG t e l . : 0228/59-3147 t e l e x : 885674

Mrs.J. R e i d Atmospheric Env. S e r v i c e 4905 D u f f e r i n S t r e e t DOWNSVI EW Onta r io Canada

L i l y Rei j c h a r d Min.of Housing,Phys.Pl. P.O.Box 450 2260 MB LEIOSCHENDAM The N e t h e r l ands t e l : 070-20936 t e l e x : 32362

A. Renlund UNEP, Reg.Office f o r Europe GENEVA Switzerland t e l e x : 28877 unep ch

.

.

A.de Reydel l e t CITEPA-I.F.E. 3, Rue H e n r i Heine 75016 PARIS France t e l . : (1)45271288

and Env.

P.O.Box 93224 2509 AE DEN HAAG The N e t h e r l a n d s t e l : 070-471414

.

W.van R i e m s d i j k Agricultural University De D r e i j e n 3 6703 BC WAGENINGEN The N e t h e r l a n d s t e l . : 08370-83300

501 T.de R i j c k M i n i s t r y o f Publ .H. and Environm. Vesal i u s Gebouw 1010 BRUSSELS Be1 g i um t e l : 02/2104872 t e l e x : 25768 mvgspf b

J.J.de R u i t e r Min.of A g r i c u l t u r e and F i s h e r i e s P.0.Box 20401 2500 EK DEN HAAG The N e t h e r l ands t e l . : 070-793911

K.A. Sahl g r e n U.N., E.C.E. P a l a i s des N a t i o n s CH-1211 GENEVA 10 Switzerland t e l . : 346011 t e l e x : 289696

H. Sas

I n s t . f o r Env. and Syst. A n a l y s i s Emmastraat 16 1075 HT AMSTERDAM The N e t h e r l ands t e l . : 020-620696

A.van d e r Schaaf Min.of F o r e i g n A f f a i r s P.0.Box 20061 2500 EB DEN HAAG The N e t h e r l ands t e l . : 070-484992 t e l e x : 31326

G. Schenone ENEL C.R.T.N. Via R u b a t t i n o 54 20134 MILAN Italy t e l . : 02-88473035 t e l e x : 310496

Schiltz Adm.des Eaux e t F o r e t s B.P. 411 LUXEMBOURG Luxembourg t e l . : 29354

J. SchmOl 1 i n g

.

A.

T. Schneider N a t . I n s t . o f Publ .H.and P.0.Box 1 3720 BA BILTHOVEN The N e t h e r l a n d s t e l . : (0)30-742970 t e l e x : 47215

lknwel tbundesamt

Bi smarckpl a t z 1 D-1000 BERLIN 33

.

FRG t e l : (030)8903-277 t e l e x : 183756 Env.Hyg.

Mrs.M. Schneider-Ferrageau de S t . h a n d Nassauplantsoen 7 3761 BH SOEST The N e t h e r l a n d s

P.K.van d e r S c h u i t R i j k s d i e n s t Monumentenzorg P.O.Box 1001 3700 BA ZEIST The N e t h e r l a n d s

Mrs.C.M. Schulte Fischedick Dep. o f Science Dynamics Nieuwe A c h t e r g r a c h t 166 1018 EV AMSTERDAM The N e t h e r l a n d s t e l . : 020-5223594

L. S e l l e r M i n i s t e r o d e l l a Santa Via L i s z t 34 ROME Italy t e l : 5916941

S.N. Semenov S t a t e Com.of Hydrometeorol ogy 12 P a v l i k Morozov S t r e e t MOSCOW- 123376 USSR t e l : 2520808 t e l e x : 07230 mcs-e

.

.

502 F. Shephard B r i t i s h Gas C o r p o r a t i o n Michael Road, Fulham LONDON SW6 2AD U n i t e d Kingdom t e l . : 01-736-334 t e l e x : 24670

A. Senni M i n i s t e r o p e r 1 ' Ecol o g i a P i a z z a Venezia 11 ROME Italy t e l . : 6786293

M. S l a v n i c h

Fed.Hydrometeorologica1 B i r c a n i nova 6 1100 BEOGRAD Yugoslavia t e l . : (011)646-555 t e l e x : y u shmz 12937

Inst.

R.C.J. Smit M i n i s t r y o f Transp.and Publ .Works P.0.Box 20901 2500 EX DEN HAAG The N e t h e r l a n d s t e l : 070-747091 t e l e x : 32562

.

Mr. Soare UNIDO P.O.Box 300 A1400 VIENNA Aust r ia t e l : 26313622 t e l e x : 135612

K. Sdderlund National Forest Service S t r a n d v e j e n 863 2930 KLAMPENBORG Denmark t e l . : 1.631166

V. S o j a t Hidromet. I n s t . o f C r o a t i a Gric 3 41000 ZAGREB Yugoslavia t e l . : 421-222 t e l e x : y u meteor 21356

J. Sousa E l e c t r i c i d a d e de P o r t u g a l Av.Julio Dinis, 9 1000 LISBON P o r t u ga 1 t e l . : 731544

O t t e l i e n van S t e e n i s Nat.Inst.of Publ .H.and P.O.Box 1 3720 BA BILTHOVEN The Nether1ands t e l . : (0)30-742970 t e l e x : 47215

P.B. Suhr M i n i s t r y o f Environment 29, Strandgade OK 1401 COPENHAGEN K Oenma r k t e l . : 45 1 57 83 10 t e l e x : 31209

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L. Szabo Nat.Aut.f.Env.Prot.and V.Arany J.u. 25 OKTH BUDAPEST H-1051 Hungary t e l . : 327-579 t e l e x : 227607 o k t h h

Env.Hyg.

Nat.Cons.

P. T a l l e r a a s M i n i s t r y o f t h e Environment P.0.Box 8013 Dep. 0030 OSLO 1 Norway t e l . : (02)117627 t e l e x : 78990

A. Tabat Bundesministerium f u r W i r t s c h a f t BONN FRG

L. T a r a s t i M i n i s t r y o f t h e Environment Box 306 00531 HELSINKI Finland t e l . : 358-0-1605503 t e l e x : y m i n s f 123717

503 Mrs.B. Thake Environmental Research L i m i t e d 106, 61 oucester P1ace LONDON England t e l . : 01.486.1211 t e l e x : 296359 e r l g

J. Thompson M i n i s t r y o f t h e Environment P.O.Box 8013 Dep. 0030 OSLO 1 Norway t e l . : (02)117510 t e l e x : 78990

J.L. T i m e r s AKZO N.V. P.O.Box 186 6800 LS ARNHEM The Netherl ands t e l : 085-663200 t e l e x : 45438

D. Tingey US Environmental P r o t e c t i o n Board 200 SW 35th S t r e e t CORVALLIS OR 97333 USA t e l : (503)757-4621

C. Tranchet

M.

.

.

Bundesamt f d r Forstw. und Lands. P.0.Box 1987 CH-3001 BERN Switzerland t e l : 031/618074

.

H. Turner Swiss Fed. 1nst.of

F o r e s t r y Res.

CH-8903 BIRMENSDORF

Switzerland t e l . : 0041-7392254 t e l e x : 827203 e a f v ch J.van der Vaart Min.of Housing,Phys.Pl. P.0.Box 450 2260 MB LEIDSCHENOAM The Netherl ands t e l : 070-209367

and Env.

.

Turnbull Department o f t h e Environment 43, Marsham S t r e e t LONDON SWlP 3PY England t e l . : 01 212 5880 t e l e x : 22221

A.A. 0.van KNMI

U1den

P.0.80X 201 3730 AE DE BILT The Netherlands t e l . : (030)766911 t e l e x : 47096 J.F.van de Vate Netherlands Energy Res.Found. P.0.Box 1 1755 ZG PETTEN The Netherl ands t e l . : 02246-4949 t e l e x : 57211 reacp n l

E.van Veen S h e l l I n t . Petroleum B.V. Carel van Bylandtlaan 30 DEN HAAG The Netherl ands t e l e x : 070-771787

J.A.van Veen Research I n s t i t u t e ITAL P.O.Box 48 6700 AA WAGENINGEN The Netherlands t e l : 08370-91216 t e l e x : 45856

Nel Venis

P. Verkerk Min.of Housing, Phys.Pl. P.0.Box 450 2260 MB LEIDSCHENDAM The Netherlands t e l : 070-209367 t e l e x : 32362

SCMO-TNO P.0.Box 186 2600 AD DELFT The Netherlands t e l . : 015-569330 t e l e x : 31453

ECN

.

.

and Env.

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H. Vygen Bundesministerium des Innern Graurheindorfer Strasse 198 0-5300 BONN 1 FRG t e l : 0228/681-3605 t e l e x : 886896

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J. Waller

R.H.

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E. Weber Bundesminsterium des Innern Graurheindorfer Strasse 198 D-5300 BONN FRG t e l . : 0228/681 4193 t e l e x : 886896

Mrs.G. Weber-Cooke B i j e r I n s t . Univ.of York Hesl ington YORK YO1 5DD U n i t e d Kingdom t e l . : (904)59861 t e l e x : 57922 y o r k u l

T. Whelan h b i o , Swedisch Royal Acad.of Box 50005 S-104 05 STOCKHOLM Sweden t e l : 8-15-04-30 t e l e x : 17073 royacad

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E.R. W i l l i a m s US Department o f S t a t e WASHINGTON DC 20003

R. Wilson Department o f t h e Envi ronment 43, Marsham S t r e e t LONDON SWlP 3PY England t e l . : 01 212 6161 t e l e x : 22221

.

.

USA

tel.:

202-6474000

.

Shell I n t . Petroleum B.V. Carel van B y l a n d t l a a n 30 DEN HAAG The Netherl ands t e l . : 070-773421

.

Sc.i

505 D.L. Winters US Department o f S t a t e WASH I NGTON DC 2 0 0 0 3 USA t e l . : 202-6474000

Mrs.A. Wright U n i v e r s i t y o f Ghent Rue Roger Abeels 9 1080 BRUSSELS Be1g i urn t e l : 2359512

A. Yde-Andersen Danish F o r e s t Experiment S t a t i o n Springforbivej 4 DK-2930 KLAMPENBORG Denmark t e l . : 01.630162

W. Z i j l s t r a VNO/NCW Lammenschanseweg 48 2313 DN LEIDEN The Netherlands t e l . : 071-130620

B.C.J. Zoeteman Nat. I n s t .of Pub1 .H. and Env.Hyg. P.0.Box 1 3720 BA BILTHOVEN The NetherTands t e l : (0)30-742045 t e l e x : 47215

F. Zuidema National Council f o r Agr.Research P.O.Box 407 6700 AK WAGENINGEN The Netherlands t e l . : 08370-19066

S. Zwerver Min.of Housing, Phys.Pl. P.0.Box 450 2260 MB LEIDSCHENDAM The Nether1 ands t e l . : 070-209360

A.F.M. Zwinkels Esso Nederland B.V. P.O.Box 7150 3000 HD ROTTERDAM The Netherlands t e l . : 010-874558

.

.

and Env.

507

ORGAN I ZATION Symposi um Chairman D.J.Kuenen National Advisory Committee

E. H.Adema J.Bervaes R.van Erpers Royaards J.van Ham W.J.Kakebeeke T.Schnei der J.F.van de Vate G. t i .Vonkeman F.B.de Walle A.J .Niggers S.Zwerver Organizing Committee T.Schneider, Chairman J. van Ham, Secretary W.J.Kakebeeke S.Zwerver Ladies Programme Mrs.M.Schneider-Ferrageau

de St.Amand

International Secretariat J.van Ham Registration and Information Centre Mrs.O.van Steenis

509

SUBJECT INDEX

Abatement options strategy Acid n e u t r a l i z i n g Capacity (ANC) Aircraft measurements Air Q u a l i t y Archives, Library, Museum model 1 ing standards A1 umi ni urn c r i t i c a l level dissolved inorganic toxicity Ammoni urn Aquatic ecosystem AQMS examples Archives Artificial rain Biological damage recovery Bridge damage

298 246, 295, 307 66, 147. 291 289 161 229 266 230 31

21 144 147

31, 69, 74, 147

31, 168 128 265 267 223 153

130 129 78

Canada Carbohydrate a1 1 ocation Cement

33, 126

Climatic f a c t o r s C l u b , 30%

235

Construction m a t e r i a l s

233, 241

Corrosion mechanism

a1

118

243 131 256

51 0 Cost- benef it a n a l y s i s

108

Cost sharing

110

C r i t i c a l 1oad

27, 148

aluminium

21

nitrogen

26

sulphur

24, 25

Cultural a r t if a c t s

77, 223

property

84, 187

Current reduction plans

299

Damage f u n c t i o n s

81

Data base

270, 310

Data comparison

312

D e c o m p o s i t i o n Rate

157

Deposition

235

dr Y pattern

29, 45, 236 30, 236, 301

Deterioration

190

Dissolution rate

73

Drinking water

149, 251

Drought

119

Ecological e f f e c t s

89, 146, 164

Economic a spec t s

78, 106

evaluation

324

losses Economic damage

86 2 44

Economic e f f e c t s e s t i m a t e s

59, 83

Effects (on)

317

forests

166, 321

l a k e s and streams

319

s o i 1s

320

EMEP

108

data

284, 297

model

285

Emission

298

control costs

108

c o n t r o l pol i c y

107, 111

reduction

127, 300

51 1

Enforcement Environmental economics Europe Exposure s t u d i e s Forest d e c l i n e distribution hypothesis USA Fresco Fresh water a c i d i f i c a t i o n

109 105 30, 45, 257, 298

55, 80, 241 29, 115 33 31 33 204 20

Ground water

65, 251, 255

His t o r i cal Background

126, 223

Impact Indoor climate outdoor p o l l u t i o n pol 1 ution Insects

234

225 207 82, 228 205

38

Land use Leaching Libraries Lichens Liming L i t t e r decomposition

312

Materials damage properties Mechanical abrasion M i crocl imate M i croflora Microphysical Processes Model

79

70, 181 223 147 27, 156 34

77, 81, 226 236

120 193

154 194 263

EMEP

284

performance RAINS

271 296

512 s i n g l e source

287

types use validation

308 266, 324 271, 289

Monuments Museums Mycorrhiza

189 223 154

National p o l i c i e s NH3 e f f e c t s

329

Nitrification Nitrogen deposition eutrophication in s o i l s saturation Nordic c o u n t r i e s Norway spruce NOx e f f e c t s Nutrient deficiencies

Ozone effects humidity and Pesticides Phosphorus depletion

168 73, 145 149 27 145 146 253 94, 166, 171 90, 167, 239 121 53, 91, 172 93 59 96 22, 47

Photosynthesis PHOXA Physiological e f f e c t s Pol i c y maker P r i v a t e wells Proton budget

308 174 324 253 143

Replacement Respiration

84 119

Scenari 0 ' s

298

comparison of Soi 1 acidification

299, 303

108, 172

142

51 3

biology chemistry

153 66, 7 1

fauna

155

PH

144

so2

dry deposition

effects Steel painted

90, 239, 299

29

165 242

Stress environmental Sugar maple d e c l i n e

322

Trajectory model Transport model Tree phys i 01 ogy response

281

125 131

309 32, 163 35, 118

Vegetation response

163

Weathering Water economy

72, 191

supply Wild l i f e

253

Yield l o s s

53, 57

Zinc

241

184 38

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