Acid Rain: A review of the phenomenon in the EEC and Europe

157 Pages·1983·10.645 MB·English

St. (Iollege
!I~ar~'s
1ibrar~
ACID RAIN
Ar eview of the phenomenon in the EEC and Europe
Ar eport prepared. for the
Commission of the European Communities,
Directorote·Generol for Environment
Consumer Protection and Nuclear Safety
by
ENVIRONMENTAl RESOURCES LIMITED
Groham& Trotman
for the Commission of the European Communities
Published in 1983 by
Graham & Trotman Limited
Sterling House, 66 Wilton Road
London SW1 V 1DE, United Kingdom
for the Commission of the European Communities,
Directorate-General Information Market and Innovation
EUR.8684
© ECSC, EEC, EAEC, Brussels and Luxembourg, 1983
Softcover reprint of the hardcover 1s t edition 1983
ISBN-13:978-94-011-5938-8 e-ISBN-13:978-94-011-5936-4
001: 10.1007/978-94-011-5936-4
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iii.
CONTENTS
page no.
SUMMARY vii
1. INTRODUCTION 1
1 • 1 Aim of the Report
1 .2 Definition and Scope of the Phenomenon
1.3 Acknowledgements 2
FINDINGS AND CONCLUSIONS 3
2. APPARENT EFFECTS 23
2. 1 Scope 23
2.2 Trees 23
2.3. Crops 24
2.4 Other Terrestrial Flora and Fauna 24
2.5 Fish and Other Aquatic Flora and Fauna 25
2.6 Buildings 26
2.7 Health 26
3. EMISSIONS AND PHYSICAL TRANSPORT 29
3.1 Introduction 29
3.2 Forecast of Sulphurous Fuels Emissions 29
3.3 NOx Emissions 32
(i~ Implications for any Future Control Policy 33
3.5 Physical Transport 33
3.6 The Effect of Emission Height 36
3.7 National Sulphur Budgets 38
4. CHEMICAL TRANSFORMATION AND DEPOSITION 41
4.1 Introduction 41
4.2 Uncertainty concerning Mechanisms of Conversion 41
4.3 Chemical Tranformation of S02 and NOx 42
4.4 Deposition of sax and Nitrates 48
4.5 Ozone 57
iv.
CONTENTS (continued)
paqe no.
5. BIOLOGICAL AND BIOCHEMICAL MECHANISMS CAUSING CHANGE
AND POSSIBLE DAMAGE TO TERRESTRIAL ECOSYSTEMS 61
5.1 The Importance of Different Pollutants 61
5.2 Direct Damage Mechanisms 62
5.3 Form of Acid Pollutants contributing to Indirect Changes
in Ecosystems 64
5.4 The Causes of Soil Acidification 65
5.5 The Mechanisms and Effects of Soil Acidification 67
5.6 Effects on Soil 70
5.7 Effects on Soil Biota 70
5.8 Heavy Metal Mobilisation 71
5.9 Extent of Soil Acidification caused by Acid Precipitation
in Europe and its Significance for Plant and Tree Growth 71
6. DAMAGE TO TREES 73
6.1 Form and Incidence of Tree Damage in Europe 73
6.2 Forest Damage in Germany 75
6.3 Mechanisms of Forest Damage by Air Pollutants 78
6.4 Conclusions 80
7. DAMAGE TO CROPS AND O'rBER PLANTS 83
7.1 Observed Damage 83
7.2 Direct Effects 84
7.3 Indirect Effects on Agriculture of Acid Precipitation 86
7.4 Conclusions 87
8. EFFECTS ON AQUATIC ECOSYSTEMS AND FISH 89
8.1 Acid Deposition 89
8.2 Evidence of Water Acidification 89
8.3 Acid Inputs to Surface and Ground Water 93
8.4 The Process of Water Acidification 96
8.5 The Decline in Fish Populations 99
8.6 Causes of Fish Damage 101
8.7 Damage to Other Aquatic Biota 103
8.8 The Relationship of Fish Status to Acid Input by
Precipitation 105
v.
CONTENTS (continued)
paqe no.
9. THE MECHANISM OF DAMAGE TO BUILDINGS 113
9.1 Introduction 113
9.2 Agents of Corrosion 113
9.3 The Mechanism of Corrosion 114
9.4 Evidence of Corrosion 115
10. THE IMPACT ON HEALTH 119
10. 1 The Potential Threat 119
10.2 Metal Concentrations in Drinking Water 119
10.3 Evidence of Health Effects 121
11. COSTS AND BENEFITS OF ACID EMISSION CONTROL STRATEGIES 123
11. 1 The Application of Cost/Benefit Analysis 123
11 .2 Damage Costs and Potential Benefits of Control 126
11.3 Emission Control Costs 132
11.4 Lime Addition to Lakes 139
11.5 Comparison of Costs of Control and Economic Benefits
of Control Strategies 140
11.6 Future Research and Control Action 142
REFERENCES 145
vii.
SUMMARY
The report examines the extent of environmental damage in the Community and
in certain other European countries that may be attributable to acid
pollutant emissions within Member States. The study assesses the evidence
for possible causal effects and considers the physical, chemical and
biological processes which have been suggested as damage mechanisms.
Concern in Europe has grown in the past few years as a result of observed
damage to forests found principally in central and southern Germany, and
also because of the loss of fish populations in the lakes of parts of south
west Norway and Sweden. More recently, a few lakes, rivers and streams in
Scotland, England and Wales, with geological and upper river catchments
similar in character to those areas of Scandinavia referred to, have also
reported absence or death of fish. Acid precipitation is considered a
possible contributory cause. Loss of needles from pine trees has also been
found in other areas of the Community. Less well appreciated is the
existence of damage to building materials, caused by short range acid
pollutant effects and the possibility under certain conditions that yields
of some crops and vegetables are affected by the dry deposition of acid
pollutants and their derivative products.
Historically most attention has focused on S02, and its oxidised 'wet'
form, sulphuric acid. Overall emissions of S02 in the Community have
declined in the last ten years and this trend may well continue. Without
further abatement measures, this decline is not likely to be more than 15%
by 2000. Recent investigations in Europe and work in the USA suggest that
NOx emissions, which arise from both stationary and vehicle fossil fuel
combustion and which are on a rising trend, may also contribute signifi
cantly to plant and tree damage. In particular ozone, of which NOx is a
chemical precursor, can, at certain concentrations under summer climate
conditions, cause damage or yield effects to some trees and plants,
possibly in conjunction with S02 and NOx'
However, it has not been unequivocably established that these environmental
impacts are caused by acid pollutant emissions, nor is the relative
importance of other factors properly identified. Also considerable further
investigations are required to understand the mechanisms involved.
Nevertheless circumstantial evidence would suggest that acid emissions and
their subsequent chemical transformation and precipitation are at least a
partial contributory cause to these observed effects and may be giving rise
to as yet unidentified impacts, some of which could be irreversible.
The costs of S02 and NOx emissions control are considerable. They also
increase on an upward rising curve in relation to the amount of S02 and NOx
removed. The benefits of control measures are currently impossible to
assess with accuracy, and in any case some effects cannot be readily
evaluated in economic terms. In considering any future control strategies,
it should be recognised that the relative costs and benefits certainly vary
from one Member State to another, and that, for some countries, trans
boundary effects are probably also a significant factor.
1.
1. INTRODUCTION
1.1 Aim of the Report
The aim of this study is to report on and evaluate:
the extent of environmental damage claimed to arise from
precipitation of acid pollutants;
the physical, chemical and biochemical mechanisms by
which acid pollutant emissions can cause environmental
change;
the trends in emissions and deposition of acid
pollutants and their derivatives.
ERL has also been asked to consider the costs and possible
benefits of alternative emission control options with the aim of
limiting any effect, and to suggest areas where further research
work is needed.
1.2 Definition and Scope of the Phenonmenon
1.2.1 Long range vis-a-vis local effects
Emissions of air pollutants can give rise to local, regionaland
international impact depending on the particular circumstances.
We have interpreted our brief to be concerned principally with
long-range rather-than local effects, in other words impacts
which result in many cases after pollutants have been mixed in
the turbulent 'mixing layer' of the atmosphere and which
therefore cannot be attributed to any particular local source.
In these situations the pollutants are generally (but not always)
more dispersed and of lower concentrations than would be the case
with ground level concentrations (emissions) resulting from local
source(s).
Nevertheless Section 9 of the report does examine the impact on
buildings of acid pollutants, since in many urban environments
this damage can be quite widespread. Also the report does
consider the importance of distance from sources as a factor in
influencing the likely type of pollutant which may cause damage,
its deposition level and resultant impact. On the other hand
respiratory health effects caused by high urban S02 with
particulate concentrations was considered not to be part of the
'acid rain' phenomenon.
1.2.2 Geographical scope
The focus of this study has inevitably been on the acid rain
phenomenon in the context of Europe, but it is not limited to the
European Community since emissions arising from within the Member
States have an effect beyond it, and vice versa. However, the
occurrence of acid rain in North America means that many of
2.
the cause and effect relationships observed there are of
relevance to further understanding of the phenomenon in Europe.
North American experience will therefore be referred to at
appropriate points during the course of the report.
1.3 Acknowledgements
During the course of its investigations ERL has received an
enormous amount of assistance in the way of information, advice
and comment from a large number of experts in government and
industrial organisations, and academic research workers in
several EEC Member States, and in North America. We would like
to record our sincere thanks for this generous assistance.
3.
FINDINGS AND CONCLUSIONS
1. WHAT IS ACID RAIN?
In a strict definition, acid rain refers to the wet precipitation
of pollutants S02/S03 and N02/HN03, which have dissolved in cloud
and rain droplets to form sulphuric and nitric acids. However,
the term has come to be more generally applied to include dry
precipitation of the gaseous pollutants and their gaseous and
particulate derivatives.
This study also includes an examination of the role and possible
ecological effects of ozone, a so called photo-oxidant (not
acidic), of which the gaseous pollutant NOx is an important
precursor. Thus effects covered under the heading of acid
precipitation include those possibly caused by ozone.
2. WHAT IS THE EXTENT OF ENVIRONMENTAL DAMAGE CAUSED BY ACID
PRECIPITATION?
In Table 1 below, we summarise the effects believed to be caused
by acid precipitation and where they have been observed, indica
ting the certainty with which such effects have been established
- see also Section 2.
Table 1
SUMMARY OF EFFECTS REPORTED TO BE CAUSED BY ACID PRECIPITATION
ESTABLISHED PROBABLE POSSIBLE
FORESTS
- acute visible Pine/spruce Pine/spruce
damage California/ FR Germany
Virginia USA, and Poland
Canada, GDR and
I - Czechoslovakia
growth(1)/ Certain pine and
! chronic effects spruce species
in areas of
FR Germany,
Netherlands,
France,
E coast USA and
Canada
CROPS/VEGETABLES
- acute damage Tobacco
southern USA.
- growth effect(2) Principally Certain crops
chronic damage winter wheat, root vegetables/
soya, maize, grass species and
peanut, radish grapes in certain
and grapes, areas of
throughout continental Europe
parts of USA and UK
contl.nued/ •••