United States
Environmental Protection
Agency
Environmental Research
Laboratory
Corvallis OR 97330
EPA-600/7-78-108
June 1978
&EHV
Research and Development
Environmental
Effects of
Increased Coal
Utilization:
Ecological Effects
of Gaseous
Emissions From
Coal Combustion
Interagency
Energy/Environment
R&D Program
Report
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are
1 Environmental Health Effects Research
2 Environmental Protection Technology
3 Ecological Research
4 Environmental Monitoring
5 Socioeconomic Environmental Studies
6 Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8 'Special" Reports
9 Miscellaneous Reports
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series Reports in this series result from the
effort funded under the 17-agency Federal Energy/Environment Research and
Development Program These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems The goal of the Program is to assure the rapid development of domestic
energy supplies in an environmentally-compatible manner by providing the nec-
essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects, assessments of, and development of, control technologies for energy
systems, and integrated assessments of a wide range of energy-related environ-
mental issues.
This document is available to the public through the National Technical Informa-
tion Service, Springfield. Virginia 22161
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EPA-600/7-78-108
June 1978
ENVIRONMENTAL EFFECTS OF INCREASED COAL UTILIZATION:
ECOLOGICAL EFFECTS OF GASEOUS EMISSIONS FROM COAL COMBUSTION
Edited by:
Norman R. Glass
Corvallis Environmental Research Laboratory
Corvallis, OR 97330
U. S. Environmental Protection Agency
Office of Health and Ecological Effects
Office of Research and Development
Washington, DC 20460
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DISCLAIMER
This report has been reviewed by the Corvallis Environmental Research
Laboratory, U. S. Environmental Protection Agency, and approved for publi-
cation. Mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
ii
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FOREWORD
Effective regulatory and enforcement actions by the Environmental Pro-
tection Agency would be virtually impossible without sound scientific data on
pollutants and their impact on environmental stability and human health.
Responsibility for building this data base has been assigned to EPA's Office
of Research and Development and its 15 major field installations, one of
which is the Corvallis Environmental Research Laboratory (CERL).
The primary mission of the Corvallis Laboratory is research on the
effects of environmental pollutants on terrestrial, freshwater, and marine
ecosystems; the behavior, effects and control of pollutants in lake systems;
and the development of predictive models on the movement of pollutants in the
biosphere.
This report further contributes to the knowledge of the EPA and will
serve to provide ecological effects information on which policy and possible
regulatory decisions can be based.
in
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ABSTRACT
This report is provided for the "Health and Environmental Effects of
Coal Utilization" Committee (Dr. David Rail. Chairman) which was created by
the request of the Department of Energy in response to the President's Environ-
mental Message. The paper is limited to an evaluation of the ecological and
environmental effects of gaseous emissions and aerosols of various types
which result from coal combustion. Throughout the report we will be dealing
with NO , SO , fine particulate, photochemical oxidant and acid precipitation
as these pollutants affect natural and managed resources and ecosystems.
In addition, synergistic effects involving two or more pollutants are
evaluated as well as ecosystem level effects of gaseous pollutants. Also, we
briefly summarize the effects on materials and atmospheric visibility of
increased coal combustion.
The ordering of pollutants into the categories mentioned above has been
done for the following reason. NO , SO and fine particulate are all primary
emissions which are proximate to tne pofter plant. Oxidant and acid precipi-
tation are pollutants which generally develop at distances from the power
plant itself and are involved in a long-range transport. Interactions or
synergistic effects as well as the ecosystem level effects involve the whole
system concept of evaluating the effects of air pollution and, hence, build
upon the information developed in the earlier sections on NO , SO etc. The
sequence in which these materials are dealt with is determined byxthe distance
from the source as well as the degree of atmospheric transport and transforma-
tion that the materials must undergo. Finally, the order in which pollutant
groups are dealt with reflects the progression of evaluating single pollutant
exposures and ends in evaluation of more complex or combined effects.
To the extent that they can be determined within acceptable limits, the
economic implications of ecological effects are identified. In addition, the
reliability of the data base upon which conclusions or estimates are made is
evaluated to the degree possible. Both the short-term, high concentration,
acute effects as well as low level concentration, chronic effects are ad-
dressed to the maximum possible extent. Aquatic and terrestrial effects are
distinguished where the pollutants in question are clearly problems in both
media. For example, since acid rain affects both air and water processes, we
have a separate discussion of the aquatic impact of acid rainfall. However,
most of the other pollutants, with the exception of fine particulate and fly
ash, do not have a significant aquatic component and will, therefore, not be
dealt with in the aquatic medium.
IV
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In order to assure that this report is on comparable grounds with the
health effects of increased coal combustion as well as other related papers
on increasing coal utilization, we have adopted the MITRE report (see Figure
1) as the starting point, or reference, for the levels of various pollutants
which can be expected nationwide in 1985 and in the year 2000 in the U.S.
both pre National Energy Plan (NEP) and assuming the National Energy Plan
scenario. In addition, this starting point assumed that new source perfor-
mance standards will be met by existing power plants as well as power plants
under construction and that best available control technology will be used in
retrofitting existing plants and in new power plant construction. Both of
these assumptions can be seriously questioned. However, in the interest of
using a uniform starting point, we have decided to use the MITRE data as the
basis. (MITRE 1977, page 51). See Figure 1.
According to the estimates in the Mitre Corporation Report (MITRE,
1977), in both the National Energy Plan (NEP) and Pre-NEP scenarios, sulfur
oxide (SO ) emissions and nitrogen oxide (NO ) emissions are projected to be
higher in 1985 and 2000 than in 1975 — SO Sbout 12 percent higher and NO
about 61 percent higher. Since SO and NO are major contributors to acidx
precipitation, substantial increases in to£al acid deposition can be expected
in the nation as a whole. At present, acid precipitation is most abundant in
the North Central and Northeastern States. Total SO and NO emissions are
projected to remain high in these regions while increasing relatively more in
the western than in the eastern regions of the country. The West's share of
SO emissions increases ,from 22 to 29 percent while NO emissions increase
from 31 to 39 percent. This means that the generally westward and southward
spread of acid precipitation detected between 1955 and 1973 (see Figure 2)
will continue. Considering that the U.S. is dominated by prevailing westerly
winds, this means that total acid deposition in the eastern parts of the U.S.
will probably increase still further.
As the MITRE Report indicates (p. 14): "In terms of gross emissions of
particulates, SO and NO , coal is the least desirable fuel for utilities and
industrial boilers. Thexheavy reliance on coal postulated in the NEP could
have substantial adverse impacts on air quality in the absence of adequate
control measures." Thus, any increase in combustion of coal relative to
other fuels will tend to increase the seriousness of the acid rain problem
unless total emissions are controlled.
A variety of ecological processes are affected and altered by air pollu-
tion, both gaseous and airborne particulates as well as aerosols. Such
processes as community succession and retrogression, nutrient biogeochemical
cycling, photosynthetic activity, primary and secondary productivity, species
diversity and community stability, community respiration, dominant or abun-
dance of key species within a community, and a variety of other attributes
and processes may all be affected by pollutants (cf. Glass and Tingey, 1975;
Dochinger and Seliga, 1976a, 1976b; Glass, et^ aJL 1977 for more complete
discussion, literature review and citations). These ecological processes may
be mediated or caused by alteration in a number of physiological processes or
mechanisms or by population changes which may occur in the dominant or
otherwise important species in a particular ecosystem.
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HYDROCARBONS CARBON MONOXIDES PARTICULATES SULFUR
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OXIDES NITROGEN OXIDES
AIR RESIDUALS LEVELS FOR 1985, 2000 RELATIVE TO 1975
Figure 1
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Estimates of the public welfare (non health-related) cost of air pollu-
tants range from several hundred million dollars per year to $1.7 billion
dollars per year. In general, these estimates include only those relatively
easily measured considerations such as the known losses to cultivated crops
from acute air pollution episodes or the cost of frequent repainting required
as a result of air pollution (Waddell, 1974). No substantial nationwide
estimates of losses to forest productivity, natural ecosystem productivity
which is tapped by domestic grazing animals and wildlife, and other signifi-
cant dollar losses are available. This is partly due to the fact that such
measurements are very difficult to make. However, the dollar losses which
have been put forward as the consequence of air pollution damage are generally
considered to be underestimates. In particular, dollar losses incurred from
long-term, chronic, low-level exposure of crops, forests, and natural ecosys-
tems to air pollutants remain viturally unmeasured nationwide.
Average pH of annual precipitation
1955-56
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CONTENTS
Abstract iv
Acknowledgements x
Ecological Effects of the Oxides of Sulfur Complex 1
Ecological Effects of the Oxides of Nitrogen Complex 5
Ecological Effects of the Particulate Complex 11
Ecological Effects of the Photochemical Oxidant Complex 15
Ecological Effects of Acid Precipitation 19
Biotic and Abiotic Interactions 24
i
Ecosystem Impacts 27
Effects on Materials 33
Effects on Visibility 36
References 39
IX
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ACKNOWLEDGEMENTS
The original draft of this paper was prepared by the following scientists
from within and outside the EPA.
Ellis Cowling - North Carolina State University, Raleigh, NC
Thomas Ellestad - Environmental Protection Agency, Research Triangle
Park, NC
Norman Glass - Environmental Protection Agency, Corvallis, OR
Gene Likens - Cornell University, Ithaca, NY
David MacLean - Boyce Thompson Institute for Plant Research,
Yonkers, NY
Delbert McCune - Boyce Thompson Institute for Plant Research,
Yonkers, NY
Paul Miller - US Forest Service, Riverside, CA
William Smith - Yale University, New Haven, CT
An extensive review of the original paper was conducted by a second,
independent group of scientists named below.
Robert Charlson - University of Washington, Seattle, WA
Leon Dochinger - US Forest Service, Delaware, OH
Walter Heck - USDA, Raleigh, NC
Stephen Hoffman - TRC, Wetherfield, CN
Orie Loucks - University of Wisconsin, Madison, WN
J. Frank McCormick - University of Tennessee, Knoxville, TN
Lars Overrein - Institute of Air Research, Oslo, Norway
Duncan Patten - Arizona State University, Temple, AZ
Eric Preston - EPA, Corvallis, OR
O.C. Taylor - University of California, Riverside, CA
David Tingey - EPA, Corvallis, OR
Leonard Weinstein - Boyce Thompson Institute, Yonkers, NY
Assistance rendered by all of the above is gratefully acknowledged.
Norman R. Glass
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ECOLOGICAL EFFECTS OF THE OXIDES OF SULFUR COMPLEX
Airborne oxides of sulfur are emitted primarily from combustion of
fossil-fuels, but other important sources include smelting of ores, pro-
duction of sulfuric acid, and other industrial processes. Two basic approach-
es have been used to study the effects of sulfur oxides. One has been to
monitor their occurrence at different sites around a source and determine
what environmental changes are associated with these exposures. The other
has been to expose plants or other receptors to known dosages under controlled
conditons and thereby derive a dose-response relationship and the effects of
various factors upon it. The goals of all these studies have been to develop
methods for the identification and estimation of the effects of air-borne
sulfur oxides, to understand their mode of action, and provide adequate
criteria for air quality standards. An understanding of the effects of SO
in the biosphere must consider that they are phytotoxic, interact with other
pollutants, and that sulfur in proper amounts is essential for all organisms.
Effects of Sulfur Oxides
Vegetation
Sulfur dioxide penetrates the leaf through stomates. In the aqueous
phases of the foliar tissue it forms bisulfite or sulfite ions, which are
then oxidized to sulfate. The sulfur derived from S02 enters the sulfur
pool, is converted to sulfur-containing compounds, is translocated throughout
the plant, and ultimately passes to the soil through exudation from roots,
elution from leaves, or leaching from litter. Sulfur may also be released
directly to the atmosphere from the leaf by the light-mediated conversion to
H2S (de Cormis, 1969).
The reactions of sulfite or its oxidation products with membranes,
enzymes, or other cellular components can produce altered metabolic functions
and changes in the ultrastructure of the cells. If sufficiently great in
rate or extent of occurrence, these changes lead to a loss of chlorophyll,
disruption, or death of the cell. The effects of sulfur dioxide at the
cetlular level may also be manifested as a decrease or increase in stomatal
aperture. Through the death or disfunction of foliar tissue or the inhibi-
tion of gaseous exchange, photosynthetic fixation of C02 by the plant is
reduced, permanently or temporarily. The gradual accumulation of sulfate in
the foliar tissue may reach toxic levels and lead to injury or premature
senescence and defoliation. The net effect of reduced photosynthesis is
altered growth and reproduction. Changes in the inorganic and organic
constitutents of foliage have also been noted (EPA, 1973; Rennie and Hal stead,
1977).
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Many factors are known to affect the response of plants to atmospheric
sulfur dioxide. The major biological factors known to affect tolerance to
S02 are species, genetic background, and a stage of development. For crop
species, the median tolerances span a 10- to 20-fold range of dosages, and
the same range of tolerance may be present in natural populations. There is
also considerable variation within any one species, and cultivars of certain
crops or selections of forest trees have been rated with respect to S02
tolerance. When leaves are fully-developed they appear to be most susceptible
to injury by S02; the foliage of conifers and evergreens appears to be most
tolerant during winter and periods of low temperature that depress metabolic
activity. Moreover, the effects of foliar injury on yield appear to be
greatest at one stage of development in the plant for crops such as beet,
cotton, or soybean (Van Haut and Stratmann, 1970).
Environmental factors significantly affect S02 tolerance and plants are
most susceptible when exposures occur at temperatures above 5-6°C, relative
humidities above 75%, in periods of higher light intensity, and with adequate
soil moisture: i.e., under conditions that most favor gaseous exchange by
the foliage. Adequate supply of mineral nutrients, particularly rritrogen and
to some extent phosphorus, calcium, and potassium, tends to increase the
tolerance of trees and crops to S02.
Taking into account both biologic and environmental factors, the degree
of risk of S02 to various kinds of cropland use have been estimated: coni-
fers, pome fruits, and berries are at greatest risk whereas cole crops,
potato, beet, and some ornamentals are at least risk (Guderian, 1977).
Animals
Toxicology studies of sulfur oxides in laboratory animals indicate that
sulfuric acid aerosol is more toxic than gaseous S02 (HEW, 1970). A consi-
deration of more recent data (summarized in EPRI, 1976) indicates that acute
exposures of mammalian systems to S02 require higher dosages to produce
deleterious effects than are necessary for the production of acute adverse
effects in vegetation. An indirect action of S02, through a change in the
suitability of plant, litter, or soil as a habitat, may be of more signifi-
cance than a direct effect on invertebrates and microfauna (Halstead and
Rennie, 1977). The same may also be true for vertebrates.
Soils
The interaction between soils and air-borne oxides of sulfur has received
relatively little attention. The two major effects of S02 pollution of the
soil are a decrease in pH and an increase in sulfate (Halstead and Rennie,
1977). A change in these two variables may then affect the structural and
microbial characteristics of the soil. In some systems where the soils are
sulfur deficient or where structure is improved by the addition of sulfur,
increased productivity may result. However, these circumstances are rela-
tively rare. When the rate of addition or the amount added is excessive,
changes in the composition, structure, and function may result. Any effect
of SO on vegetation will indirectly affect the soil. A reduction in vegeta-
tive canopy allows greater solar radiation to penetrate to the soil and the
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reduction in litter accumulation leads to greater extremes in temperature,
less retention of moisture, and a greatly altered microclimate in the upper
soil horizon.
Other Effects
Microorganisms are essential for the functioning of terrestrial and
aquatic ecosystems through their roles in primary production, nitrogen
fixation, and in decomposition processes. The impacts of air pollution on
these organisms have not been studied extensively. Recent work suggests that
adverse effects on photosynthetic carbon fixation can be induced in blue-
green algae by low concentrations of S02 (applied as bisulfite). Other types
of algae were relatively resistant. Respiration of bacteria and protozoa
indicated that these groups are also relatively tolerant (Wodzinski et al.,
1977).
Indirect Effects
Indirect effects of SO include changes in the occurrence of pathogens
and destructive insects. SO in combination with other gaseous and particu-
late pollution has resulted Tn additive, synergistic and antagonistic respon-
ses among certain insect pests and some pathogenic organisms, (see section
on interactions).
Tolerance to S02 in spruce has been associated with resistance to other
stresses (Guderian, 197)). Consequently, genetic shifts and changes in
community diversity may result from long-term exposures.
Magnitude of the Effect
Recent Canadian estimates(Rennie and Hal stead, 1977) of the magnitude of
the problem in Canada indicate that 6.5 x 106 metric tons of S02 are emitted
annually; areas affected adversely cover between 1.1 to 2.5 x 104 km2; and
direct economic losses to forestry lie between $1.2 and $2.8 x 106. A 1971
estimate (Benedict, et al. 1971) of the annual losses in the United States
owing to the effects of S02 on plants was $6.2 x 106; and pollution threatened
areas were estimated to total about 13% of the land area of the USA in which
57% of the national population resided.
Both of the above studies indicate that uncertainties are present in
their estimations as to the real extent and degree of economic effects.
Moreover, both are of the opinion that the values given may be underestimates.
Base'd upon projected small increases in SO emissions (Figure 1) there is
little likelihood of significantly increased effects on vegetation. However,
in areas directly influenced by SO emissions and/or in those areas where
there is at present small margin'of safety for vegetation injury the proba-
bility of increased risk to vegetation may be large.
Areas of Uncertainty
Perhaps one of the most uncertain and controversial problems is the
relation between exposure and effect. The occurrence of foliar injury and
aesthetic damage may largely be due to short-term, high-level exposures. At
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least three quantitative formulations have been given for liminal exposures
with time (duration of exposure) and dose-rate (atmospheric concentration) as
variables, with changes in concentration being relatively more important than
changes in time. One formulation also indicates the total dose needs to be
evaluated also with respect to the frequency of exposure (Male et a_K ,
1977). Effects on crop yield are not always related to foliar injury and the
chronic as well as acute exposures over the course of a growing season must
be weighed. For the estimation of adverse ecological effects, not only acute
and chronic exposures but also total sulfur input to the system, as estimated
by the annual mean loading, may be of significance.
Researchers need air-monitoring data that is sufficiently thorough to
indicate the functions and range of parameters that adequately describe
realistic exposures. It should be noted that the joint distribution of S02
and other air pollutants is also of concern. Furthermore, attention should
be given to the occurrence of H2S04 where meteorological conditions or cooling
tower drift may promote its near-site occurrence.
The biological data base should also be expanded to include more informa-
tion on the statistics that characterize the tolerance of natural populations,
especially those of more arid regions. Most of our knowledge is derived from
agricultural crops and species of temperate forests. This biological data
base should also be expanded by a further inventory of effects, particularly
at the ecosystem level which are of a cumulative and indirect nature, i.e.,
those that deal with the biotic interactions of pathogen or pest with host,
competition and selection in communities and populations, and biogeochemical
changes.
Particular attention should be given to the following problem areas:
(1) Dose-response: an acceptable model that relates these two variables
is still needed. Adaptation and further development of air-surface
transport models probably offer the most efficient route and best
means of incorporating the effects of biological and environmental
factors and transients. Further studies with controlled exposures
may be needed to estimate model parameters.
(2) Thresholds: there is a need to elucidate the mechanisms and capaci-
ties of micro-(metabolic) and mega-(bio-geochemical) systems to fix
atmospheric sulfur. Such knowledge is necessary not only to predict
maximum tolerable concentrations in the short-term but also sorptive
capacity of vegetative sinks for the long-term.
(3) Interactions: considerable work still needs to be done to give a
reasonable description of the interactive effects of two or more
pollutants in combination.
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ECOLOGICAL EFFECTS OF THE OXIDES OF NITROGEN COMPLEX
The combustion of fossil fuels produces oxides of nitrogen; higher
combustion efficiency results in increased production of this pollutant. The
increase in fossil fuel consumption necessary to meet future national energy
requirements, coupled with reductions in imported oil, increases in domestic
coal utilization, and improved combustion technology, will result in greater
emissions of nitrogen oxides (Figure 1).
Nitric oxide (NO) is the predominant oxide released in combustion. It
enters the photolytic cycle and is converted to nitrogen dioxide (N02) and
ultimately to other oxides of nitrogen. Of the various oxides of nitrogen,
only NO and N02, collectively referred to as NO , are recognized as important
air pollutants with respect to their potential adverse effects on living
systems.
The effects of NO is necessarily complex because nitrogen is an element
essential to all biological systems, it is toxic by itself, and it partici-
pates in the atmospheric formation of other air-borne pollutants.
Natural sources account for more than 90% of global oxides of nitrogen
(NRC, 1977) and the most abundant of them, nitrous oxide (N20). Anaerobic
bacterial action and chemical decomposition of nitrate are considered the
major natural sources of NO. Forest fires and other uncontrolled combustions
contribute only a small portion of atmospheric NO . However, even though
natural sources of NO are large compared with manmade sources, there are two
considerations which fiake manmade sources of critical importance. First,
nitrous oxide constitutes over half of the world wide naturally emitted NO
compounds, but it is not considered a pollutant because it is in low ambient
concentrations and does not appear to be involved in the nitrogen dioxide
photolytic (photochemical smog forming) cycle. Second, local concentrations
of manmade NO are often large compared with background ambient levels and
are involved as oxides precursors which enter into the photochemical reactions
leading to air pollution.
In 1970 the two major classes of man-made sources of NO , mobile and
stationary, contributed 51% and 46%, respectively, of the total NO emissions
in the United States. Nearly 80% of the mobile sources of N0x were from
motor vehicles. NO emissions from electric power generation alone could
increase from a 197$ base of 3.95 x 106 tons/year to 7.89 or 16.57 x 106
tons/year by 1990; the larger emission predicted assumes no enlargement in
nuclear plant capacity (U.S. Senate, Committee on Public Works, 1975).
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The occurrences of NO in concentrations that directly affect the most
susceptible components of terrestrial ecosystems (vegetation) are not the
result of emissions from mobile, or most stationary sources. Rather, direct
effects of NO , where they occur, are confined to localized areas near
industries that use or manufacture nitric acid, and are usually associated
with accidental acute exposure.
Effects of Nitrogen Oxides
Vegetation
Nitrogen oxides are significantly less phytotoxic than other constituents
of the photochemical oxidant complex, and their major importance in the
atmosphere with respect to vegetation injury is an indirect one: i.e.,
participation in photochemical reactions resulting in the production of
atmospheric oxidants, including both ozone and the peroxyacyl nitrates.
Two recent reviews (Maclean, 1975; NRC, 1977) presented an overall
synthesis of N02 induced effects in plants. Atmospheric N02 is absorbed by
plants primarily through stomata, whereupon it changes from a gaseous to an
aqueous form. It alters the pH of the cellular milieu and reacts with
cellular constituents leading to altered metabolism, ultrastructural changes,
reduced photosynthesis, and probably many other effects that have not been
observed or measured. These, in turn, lead to effects at progressively
higher levels of biological organization. Premature senescence, chlorosis,
necrosis, or abscission of leaves affect the entire plant causing reduced
growth or reproduction, and even death of individual plants or entire plant
communities.
Because of the relationship between the concentration of N02 and the
duration of exposure, there is no single threshold dose for an effect in
plants. Rather, threshold doses are usually described as functions of pollu-
tant concentration and exposure time (Figure 3). The threshold curves in
Figure 3 are approximations to indicate the N02 doses that result in: the
death of plants; foliar lesions; and metabolic or growth effects. At N02
concentrations below the threshold for metabolic and growth effects, vegeta-
tion can serve as a sink to remove N02 from the atmosphere (Hill, 1971), and
this absorbed N02 may be metabolized by the plant.
Animals
The aim of experimental exposures of animals to NO has been more to
elucidate potential hazards to human health than to detirmine effects on
animals per se. Experiments with animals that used extremely high concentra-
tions of N02 for short periods or lower concentrations for very long periods
have induced pulmonary and extrapulmonary effects and mortality. However,
prolonged exposure to N02 concentrations of up to 0.5 ppm did not affect
normal laboratory rats, mice, or rabbits (NRC, 1977). In short-term exposures
(1-hour) the mortality threshold for those animal species was 40 to 50 ppm
N02 (Mine et al. , 1970). However, there is no evidence that current levels
of atmospheric NO , even those that occur in large urban areas (e.g., Los
Angeles), have an effect on animal communities.
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Soils
Studies to assess the relation between atmospheric NO and effects on
soils are limited. Both NO and N02 react readily with soils and are usually
converted to nitrate, and sorption of large amounts of N02 under experimental
conditions decreases soil pH (Ghiorse and Alexander, 1976). Little is known
of the effects of NO on the microfauna and microflora of the soil. Although
these microorganismsxare critical to the balance in terrestrial ecosystems,
experimental evidence is limited to the responses of individual species
in vitro. These experiments have demonstrated that high concentrations of
NO affect growth or survival of individual microorganisms in defined media,
but effects at NO concentrations likely to be encountered in the ambient
atmosphere are unknown (NRC, 1977).
Other Effects
Because of the importance of microorganisms in primary production,
nitrogen fixation, and decomposition processes, a reduction in these activi-
ties by air pollution could have serious consequences in terrestrial and
aquatic ecosystems. Wodzinski et aK (1977) found profound effects on
photosynthetic carbon fixation in blue-green algae by exposure to low concen-
trations of N02 (applied as nitrite). Other types of algae were relatively
resistant, as was the rate of respiration in bacteria and protozoa.
Indirect Effects
Indirect effects would include the participation of NO in atmospheric
reactions leading to the production of other, more toxic photochemical
oxidants i.e. ozone and peroxyacyl nitrates and an increase in the rate of
transport or the amount of nitrogen passing through the ecosystem. An
example of indirect effects of NO is the combined influence of NO and one
or more other air pollutants when they occur simultaneously (See section on
Interactions).
Summary of Nitrogen Oxide Effects
1. Higher plants are the most susceptible receptors in the terrestrial
ecosystem.
2. The indirect effects of NO (i.e., its role in the formation of
ozone and peroxyacyl nitrates and the synergistic effects on plant
injury of low concentrations of N02 and sulfur dioxide mixtures)
are probably more important than direct effects.
3. N02 is more toxic than NO.
4. Limited studies with animals indicate that very high N02 concen-
trations are required for morbidity or mortality.
8
-------
5. Soils absorb NO , which is converted to nitrate, but effects of NO
on soil-borne microorganisms have not been investigated.
6. • As a component of acid precipitation, NO is part of a pollutant
complex which does exert substantial ecological impact as discussed
under the acid precipitation section of this report.
Magnitude of the Effect
Atmospheric NO is relatively unimportant in its direct effect on
ecosystems relative to other major pollutants. Concentrations of NO
necessary to affect susceptible members of the terrestrial ecosystemx(vegeta-
tion) are much greater than for sulfur dioxide and other photochemical
oxidants. Estimates of the economic impact of air pollutants on vegetation
(Benedict et al_. , 1971) did not include NO by itself; rather, it was com-
bined with ozone and peroxyacetyl nitrate.x
As noted above, injury to vegetation from atmospheric N02 is usually the
result of accidental releases or spills of NO and it is localized. Wide-
spread effects probably do not occur. For example, the average N02 concen-
trations in most major cities of the United States are well below the thresh-
old for effects on metabolism and growth of plants (Figure 3). The maximum
N02 concentrations recorded in Los Angeles (EPA, 1971) for an entire year
(1966) were only slightly higher than the thresholds for averaging times of
one day or less, and below the curve for longer sampling periods.
i
The real importance of NO , however, is probably its potential for
indirect effects on environmental quality. The synergistic effects on plant
injury of low concentrations of N02 and sulfur dioxide found in experimental
exposures, and role of NO in the production of photochemical smog and acid
precipitation are probably* where NO poses the greatest threats. Even though
NO emissions will increase substantially (Figure 1) one can not reliably
estimate any change in the direct or indirect effects, based on our limited
knowledge of NO effects.
Areas of Uncertainty
According to one estimate (MITRE, 1977), increases in nationwide emis-
sions of NO will be 61% higher in 1985-2000 than they were in 1975. At
local levels', near power plants for example, emissions will be even greater.
An understanding of the significance of an increase in N0x emissions can
best be realized by the development of models to predict the concentrations
and dispersal of NO around power plants. This kind of information is
necessary to designxfumigation experiments in which the exposure regimes can
be programmed to simulate those that are likely to occur. These models are
not yet available.
The direct effects of NO become more relevant as emissions increase.
Research should initially empfiasize effects on vegetation because of its
susceptibility relative to other classes of organisms. Since plants and
other organisms are relatively insensitive to NO, research should concentrate
-------
on N02. The gross effects of acute N02 exposures on metabolism, growth, and
yield of crop plants and population changes in natural plant communities are
unknown. The importance of soils and vegetation canopies as sinks for the
removal of NO and its metabolic role is not well understood. Thus the
possible effects of NO as a source of nitrogen in the biosphere have not
received serious attention.
Laboratory exposures of animals should be carried out in parallel with
field investigations to assess effects on population dynamics, behavior, and
reproductive success. The effects of NO in combination with other gases and
metals is poorly defined (see section onxlnteractions).
10
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ECOLOGICAL EFFECTS OF THE PARTICULATE COMPLEX
Coal and oil fired electric power plants are among the largest anthropo-
genic point sources of participate matter. Adoption of electrostatic pre-
cipitation for up to 98 percent of the particulates produced by coal combus-
tion is rapidly reducing the particulate emissions from these sources. If
new plants continue to follow best available control technology (BACT), and
progress can be made in converting non-conforming plants to BACT, total par-
ticulates from power generation and heating could be reduced 30 percent or
more by 1985 (MITRE 1977), in spite of greatly expanded coal utilization.
The significance of the remaining particulates for visibility and biological
function is still a serious question because of our incomplete understanding
of particle chemistry, transport and interaction with the biota. Fortunately
several excellent reviews are available on selected aspects of this topic.
These include Berry and Wallace (1974), Vaughan et a_L (1975), Van Hook and
Schults (1977), and NRC (1977).
Size, Transport and Deposition
Particulate contaminants originating from coal combustion with best
available control technology are released into the atmosphere in sizes ranging
from 0.1 to 6 micrometers. In the absence of rainfall, size is of great
importance because of the potential that particles of this size will remain
airborne for days or weeks and be transported 100 to 1000 km. Other studies
have shown that less than 5 percent of the particulates from large power
generating facilities will reach the ground or be intercepted by vegetation
within a 20 km radius. These emissions, therefore must be viewed as a re-
gional or global problem.
The mechanics of deposition of particles on natural surfaces has been
gleaned from studies with particles ranging from 1 to 50 micrometers, as
reviewed by Chamberlain (1967) and Ingold (1971). Particulates can be
deposited on natural surfaces by three processes: The largest by sedimenta-
tion under the influence of gravity but little of this size remains under
BACT; impaction on obstacles to air flow (e.g., vegetation under the influence
of 'eddy currents); and deposition under the influence of precipitation. For
particles of the 0.1 to 3 micrometer size range, impaction is most important.
It occurs when air flows past an obstacle and the airstream divides, but
particles in the air tend to continue in a straight path due to their momentum
and strike the obstacle. The efficiency of collection via impaction increases
with decreasing diameter of the collection obstacle and increasing diameter
of the particle.
11
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Ingold (1971) presented data indicating that leaf petioles are consider-
able more efficient particulate impactors than either the twigs (stems) or
the leaves of plants. For particles of dimensions 1-5 micrometers, inter-
ception of fine hairs on vegetation is possibly the most efficient retentive
mechanism. The capturing efficiency of raindrops falls off very sharply for
particles of 5 urn or less. Participate removal by stomatal uptake has been
suggested (Jordan, 1975) and photographed by Helmke et al. (1976), but it is
infrequent. When it occurs, stomatal function fails.
Thus the surfaces of vegetation provide a major filtration and reaction
surface for the transfer of fine particulate pollutants from the atmosphere
to the biosphere. The capability of plants to act as a sink for air contami-
nants has been recently reviewed (Smith and Dochinger, 1976). The hypothesis
that plants are important particulate traps is supported by evidence obtained
from studies dealing with radioactive, trace element, pollen, spore, salt,
precipitation, dust and unspecified particles.
Effects of Fine Particulates and Areas of Uncertainty
The significance of fine particulates for plants and animals derives
from certain aspects of their physical presence and their chemical composi-
tion. Constituents with potential toxicity for plants include B, Cd, Co, Cr,
Cu, F, Ni, Tl, and V. Constituents important for animals include Be, Cd, F,
Hg, Ni, Sb, Se and Tl. The five trace elements with greatest potential for
adverse impaction on the terrestrial biota, ranked in descending order of
biological impact and research need include Cd, Ni, Tl, Cu and F (Van Hook
and Schults, 1977). Of particular interest is the evidence suggesting that
some trace elements are preferentially concentrated on the smallest particles
(Linton et al., 1976). Some elements also are present in the gas phase
(Natusch, 1975; Natusch and Wallace, 1974; Andren et aJL , 1975; Pellizzari et
al., 1975; Jones et al., 1976). While enrichment of particles appears to be
independent of plant operating conditions, stack gas temperature strongly
influences the distribution of elements between phases.
Recently, much more concern is being expressed about the potential
toxicity of polycyclic aromatic hydrocarbons (PAH) which are released in coal
combustion and can be condensed on the fine particulates. Studies in Norway
(Lunde et a_L , 1976) have shown significant quantities of these compounds on
particulates collected from regional air samples over southern Norway. Since
the PAH compounds are known to be active in metabolism (including enzyme
induction) and generate a wide range of metabolites, research is beginning to
focus on their "importance as carcinogenic agents for all animals breathing
fine particulates, and for aquatic organisms taking up these compounds from
the surrounding water (Lech and Melancom et al., 1977). Current research
indicates important effects induced in fish at dilutions of a few parts per
billion, well below levels observed in the Norwegian rain-water samples, but
the hazard for human use of the fish is still unknown. Since most particu-
lates in the future will be in the fine aerosol size, the 30 percent reduction
in tonnage of emissions given in Fig. 1 may or may not represent a reduction
in ecological hazard, depending on activity of these organic compounds.
12
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Evidence also is available to indicate that the soil component of
terrestrial ecosystems is an important sink for fine participates. Studies
of the ecology of soil ecosystems are concerned with the potential inter-
ference that the above trace elements can have on the metabolism of micro-
organisms, arthropods and other soil animals.
Many of these organisms are involved in organic matter decomposition or
mineralization. Subtle changes in these processes could have profound
effects on ecosystem function by altering the quality or quantity of nutrient
cycling (Bond et a_L , 1976; Lighthart and Bond, 1976).
Acute plant disease is infrequently ascribed to particulate contamina-
tion. Particulates, therefore, are generally not considered harmful to
vegetation (Jacobson and Hill, 1970; U.S.D.A. Forest Service, 1973). In
numerous and varied situations, however, particulates have been implicated in
subtle adverse vegetation effects (Lerman and Darley. 1975).
Still another consequence of fine particulates is the reduction in
photosynthesis occasioned by reduced light from atmospheric contamination
(Czaja, 1966; Darley, 1966; Treshow, 1970). Reduced photosynthesis due to
increased stomatal diffusion resistance caused by particulate plugging has
also been proposed (Ricks and Williams, 1974). Slight tissue burning appears
in electron micrographs of fly ash particles on leaves (Lech and Melancom,
1977), a suspected result of the organic compounds on the particles. Quanti-
tative estimates of the. importance of these effects are available.
Summary
1. The fine particulate materials emitted by coal-fired power genera-
ting plants using best available control technology can remain
airborne for a considerable period of time; probably less than 5
percent of these materials will reach the ground or be intercepted
by vegetation within a 20 km radius of the source.
2. Particles are deposited on natural surfaces by sedimentation,
impaction, and in precipitation.
3. Plants are important sinks for particulate pollutants and the fine
hairs present on the surface of plants are the most effective
interceptors of these particles.
. 4. Particles containing heavy metals, other elements, and polycyclic
organics may have adverse effects on terrestrial and aquatic biota.
5. The soil is also an important sink for fine particles and there is
concern that the contamination of soils with heavy metals could
alter the normal processes associated with microflora, microfauna
and nutrient recycling.
13
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6. Although fine particles are relatively non toxic to plants, fly ash
has been reported to induce foliar lesions and reduction in photo-
synthesis because of reduced light or interference with stomatal
function.
7. There are interrelationships between fine particles and the inci-
dence and severity of infestation by certain insects and mites (see
section on Interactions).
14
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ECOLOGICAL EFFECTS OF THE PHOTOCHEMICAL OXIDANT COMPLEX
Photochemical oxidants, namely ozone (03) and to a much lesser extent,
peroxyacyl nitrates (PANs), are the most damaging air pollutants affecting
agriculture and forestry in the USA (Jacobson, 1977). Of the homologous
family of PANs, peroxyacetyl nitrate (PAN) is most common in polluted atmos-
pheres. It is more phytotoxic than 03 but the ambient concentration of PAN
is much lower than 03 (Taylor, 1969). Formation of oxidants in the atmosphere
has a complex dependence on amount of primary precursors (nitrogen dioxide
and hydrocarbons) present, meteorological conditions and time of day (NAS,
1977). Therefore, it may be assumed that the substantial increase in nitro-
gen oxides (NO ) predicted for 1985 and 2000 (Figure 1) suggests a concomitant
increase in oxidants in coming years.
Plant Effects
Investigations in the early 1900's provided evidence that low concentra-
tions of ozone could produce foliar lesions but the first observation of
injury on field grown plants was reported in the early 1940's (Middleton et
al., 1950). The photochemical oxidants have constituted a chronic problem in
southern California for more than 30 years. The extent and severity of
losses to agricultural crops, exclusive of forests, native vegetation and
ornamental plantings, increased to $3 million in 1953 (Middleton et al.,
1956) and by the 1970's crop damage in the state had reached more than $55
million (Millecan, 1976). Millecan also reported that 18 different crops
could no longer be profitably grown in some areas of southern California. A
crop loss of $5 million was reported for Connecticut in 1953 (Heggestad,
1966).
Chronic oxidant injury to ponderosa (Pinus ponderosa Laws) and Jeffrey
pine (P. Jeffrey Griv. and Balf.), the dominant species comprising the mixed
conifer forest ecosystem in the San Bernardino (SBNF) and Angeles National
Forests (ANF), has been estimated using aerial photography. In the SBNF,
46,230 acres had heavy ozone type injury, 53,920 acres moderate injury and
60,800 acres light or no injury (WERT et aJL , 1971). Severity of injury to
ponderosa and Jeffrey pines at selected'plots in the SBNF generally increased
between 1973 and 1975 and the mortality rate was as high as 6-8% (Miller et
a_L , 1977).
Annual observations in the Cleveland National Forest of southern Cali-
fornia showed increased injury from 1974 to 1976 (U.S. Forest Service, 1977).
15
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A ground survey of parts of the Sequoia Natinal Forest (SNF) in 1974
revealed 24 locations where foliar symptoms of 03 were present on one or more
species (Williams et aJL , 1977). Oxidant injury to similar forest tree .
species has been identified in other locations in California (Miller and
Millecan, 1971) but the most important examples are in the ANF, SBNF and SNF.
In the eastern United States "Emergence tipburn" of eastern white pine
(P. strobus L.) is associated with elevated 03 (Berry and Ripperton, 1963).
Injury to new needles was induced in the field by 0.03 ppm 03 for 48 hours
and 0.07 ppm 03 for 4 hours (Costonis and Sinclair, 1969). Morris (1973)
found that 30% of the white pines in one area of Shenandoah Valley of Virginia
developed injury while 5% were considered severely affected.
More important in the east, however, is the widespread damage to a wide
variety of crops, particularly dry beans, grapes, potatoes, and tobacco.
Moderate damage is reported on these and some other crops almost every year
east of the Mississippi River and any increase in damage would have serious
consequences economically.
Sources of Oxidant Precursors
The urban source of primary pollutants was as far as 80 to 160 Km
upwind in each of the chronic oxidant injury incidents to forest vegetation
cited above. The afternoon onshore flow through the "reactor" (Southcoast
air basin) and upslope to the forested mountains is an example of a set of
terrain and meteorological conditions which produce adverse oxidant concen-
trations in the forest (Edinger, 1973). An area source the size of metropoli-
tan Los Angeles could cause ozone concentrations to exceed the federal
standard of 0.08 ppm at locations as far away as 250 Km (Blumenthal et al.,
1974) and the effect may carry over more than one day. At St. Louis the
federal standard was exceeded at distances as far as 150 Km downwind (White
et aj., 1977). In the midwestern and eastern United States, high ozone
concentrations in rural areas result from a high pressure system as it moves
from west to east. A large system with a radius of 375 Km or more with high
ozone may result as precursors are picked up over densely populated areas
during the west to east movement (Ripperton et aj., 1977).
Tesche, et aj. (1977) and Hegg et a_L (1977) concluded that no ozone was
synthesized in the "near field" (out to 90 Km) of plumes from coal or gas
fired plants but Davis et aJL , (1974) suggested that 03 synthesis did occur
close to such squrces. In either case the potential for increased 03
synthesis beyond the 90 Km point during the passage of a large high pressure
system (Ripperton et a_L , 1977) is a distinct possibility.
Effects On Other Organisms
Although ozone and PAN effects are best known on vascular plants, several
researchers have reported measurable effects of ozone at ambient concentra-
tions on various phases in the life cycle of pathogenic organisms (NAS Report,
1977). Ozone and mixtures of ozone with sulfur dioxide were shown by one
researcher to decrease the population of four nematodes associated with
soybean (NAS Report, 1977).
16
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Direct effects of ozone and PAN on arthropods have not been documented
but oxidant (ozone) injury to ponderosa pine was shown to predispose trees to
later invasion by pine bark beetles (Miller et aJL , 1977). The beetles
increased the rate of decline and may be considered the final cause of tree
death.
There is no documented evidence that free ranging mammals, birds and
reptiles are directly affected by 03 and PAN air pollutants but it is readily
apparent that severe injury to a wide variety of vascular plants may drasti-
cally alter food availability and cover for such animals.
No direct effect of oxidant pollutants on aquatic habitat and soils has
been established. Because of the strong oxidizing potential it has been
assumed that the oxidants react at the surface of the soil and bodies of
water and little if any penetration occurs. Soil and aquatic organisms are
thus assumed to be protected against direct impact from the oxidants.
Areas of Uncertainty
Areas of uncertainty which may have an important bearing on the effect
of photochemical oxidants on the ecosystem associated with the expansion of
coal utilization are:
(1) What added injurious effects will result from simultaneous occur-
rence of other pollutants emitted by coal combustion? What effect
will the projected increase in NO and decrease in hydrocarbon
(MITRE, 1977) have on ambient oxiaant levels? How will dose re-
sponse relationships be altered by increased levels of C02?
(2) What are the relative stabilities of organism populations in dif-
ferent types of ecosystems? Will changes due to air pollutants be
irreversible?
(3) Can criteria be developed to interpret or evaluate services rendered
by ecosystems in addition to the value of harvestable products?
Summary
One of the most threatening aspects of the photochemical oxidant problem
is the long range transport of plant damaging concentrations in urban plumes
even at present levels of precursor emissions. During periods of high mete-
orological potential for air pollution the elevated ozone concentrations
become a regional phenomenon in both the eastern and western United States.
Repeated episodes during 4 to 6 months of the year are sufficient to cause
obvious foliage injury, impaired photosynthesis and growth reductions of
sensitive species populations, in both agricultural and forest ecosystems.
During the last 20 to 30 years, the problem of elevated oxidant concentrations
has become a new stress in several ecosystems particularly in the Southwest.
17
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Energy policy options which have the potential for increasing NO
emissions will surely affect the extent and the intensity of photochemical
oxidant stress in ecosystems on both a local and regional scale. The kinds
and number of changes to be expected in the biotic communities comprising
affected ecosystems can only partially be anticipated with the present state
of knowledge and methodology. The "goods and services" formerly provided by
certain ecosystems may be in short supply or perhaps nearly eliminated. The
costs in time and energy required to attempt conversion back to a condition
that could accomodate former "demands" may be unacceptable even if methods
were identified and tested.
18
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ECOLOGICAL EFFECTS OF ACID PRECIPITATION
In addition to naturally occurring sulfur oxides and hydrogen sulfide,
atmospheric loads of sulfur which lead to acidic precipitation in various
regions are augmented by sulfur dioxide and particulate sulfate from a com-
bination of fossil fuel combustion and from industrial processes. Further,
nitrogen oxides also contribute to acid precipitation.
Sulfur and nitrogen compounds are removed from the atmosphere by two
processes; a) dry deposition including the absorption of S02 on exposed
surfaces and the sedimentation and impaction of particulars and b) wet
deposition in which sulfur compounds are frequently deposited as acid precip-
itation. Acidity of precipitation should be understood as a reflection not
only of the amounts of sulfuric, nitric, hydrochloric, and organic acids in
the Atmosphere, but also as a reflection of the balance between all the
cations and anions dissolved in precipitation. Some of these ions include
beneficial nutrients; other are injurious to plants and animals.
Dry deposition is' a continuous process depending mainly on the concentra-
tion of sulfur oxides near the ground, the yearly amounts deposited generally
decreasing with increasing distance from the source. Wet deposition is much
more variable being dependent both on the rainfall pattern and on the burden
of sulfur compounds within the mixing layer. It can be substantial in areas
exposed to precipitation from air which has passed large emission sources.
In cold climates air pollutants deposited during the winter usually accumulate
in the snow pack. When this melts, much of the pollutant load is released in
concentrated form with the first melt water. This may lead to sudden in-
creases of acidity in the watercourses and also to some extent in the soil.
Strong acids, such as sulfuric, nitric and hydrochloric acid, have
lowered the pH of rain and snow falling on much of eastern U.S. to between 3
and 5. Recent data indicate that in the U.S. there has been both a south-
westward and westward extension of the region of acid precipitation and an
intensification of acidity in the. northeastern region since the mid-1950's.
As shown earlier in Figure 2, precipitation in a large portion of the eastern
Un'ited States was less than pH 5.6 in 1955-56; the zone of greatest acidity
(lowest pH) was generally consistent with the zone where sulfur emissions
were high. By 1973, however, the region of low pH embraces most of the area
east of the Mississippi River.
Currently, the pH of precipitation in much of the northeastern U.S.
averages between 4.0 and 4.2 annually. But values between 2.1 and 3.6 have
been observed for individual storms at various locations (Likens and Bormann,
1974 and 1975; Likens, 1976) in most cases many hundreds of kilometers from
major sources of air pollution.
19
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Similar pH patterns have been reported in northwestern Europe. For
example, in Norway the maximum wet deposition of pollutants occurs in the
southern part of the country, and the mean pH is below 4..3.
Data from New York State and New England indicate that about 60 - 70% of
the acidity is due to sulfuric acid (Galloway et aj., 1976; Likens, 1976).
Along with the important role of sulfur in affecting acidity, studies in New
York State and New Hampshire indicate that the relative importance of nitric
acid has increased during the last 10 years (Likens, 1976).
Effects of acid precipitation on aquatic ecosystems
Freshwater bodies in many areas of eastern North America and northern
Europe, that today lie in and adjacent to the areas where precipitation is
most acid, are threatened by the continued deposition and further expansion
of acid precipitation. Many of these bodies of fresh water are poorly buf-
fered and vulnerable to acid inputs. These ecosystems appear destined to
suffer greater acidification and loss of fish populations. Equally as serious
as damage to fish are the less conspicuous effects of the acidification of
fresh water, including changes occurring in communities of aquatic organisms
such as microdecomposers, algae, aquatic macrophytes, zooplankton and zooben-
thos.
Unpolluted, soft water lakes are generally dilute solutions of Ca and Mg
bicarbonate. The bicarbonate system constitutes the main buffering system in
the water. Lakes in regions underlain by highly resistant, carbonate-poor
rocks have low buffer capacities, and are vulnerable to input of acid precip-
itation.
Large areas of the U.S. are underlain by granitic rock and are potential-
ly sensitive to acid precipitation, e.g. northeastern U.S. (e.g. Galloway and
Cowling, 1977). A major number of the lakes in Scandinavia fall within this
category, especially above the postglacial marine limit where the bedrock
over large areas is covered by only thin glacial deposits. A continuous
supply of acid substances to lakes and streams eventually leads to the deple-
tion and loss of the normal buffer system, pH falls to below 5.0 and sulfate
becomes the major anion. Such lakes have only minimal capacity to neutralize
additional inputs of acid; and new inputs of acid cause sharp drops in pH
(Gjessing et ah , 1976).
The acidification of thousands of lakes and rivers in southern Norway
and Sweden during the past two decades has been linked to acid from precipi-
tation (Dochinger and Seliga, 1976; Braekke, 1976; Wright and Ggessing, 1976;
Aimer et aj., 1974; Dickson, 1975). In turn, this increased acidity has
resulted in the decline of various species of fish, particularly trout and
salmon. The fish population in rivers and lakes in 20% of the area of south-
ern Norway have been affected by increasing acidity.
About 10,000 Swedish lakes are estimated to have been acidified to a pH
below 6.0 and 5,000 lakes to a pH of less that 5.0 (Dickson, 1975). Along
the west coast of Sweden, about 50% of the lakes have pH values of less than
20
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6.0 and pH has decreased as much as 1.8 units since the 1930's. Fish popula-
tions have been correspondingly decimated or seriously affected (Dickson,
The first reports in North America linking lake acidification and the
extinction of fish populations to acid precipitation were derived from studies
of lakes in the vicinity of Sudbury, Ontario. Populations of lake trout,
lake herring, white suckers and other species disappeared rapidly during the
1960's from a group of remote lakes in the LaCloche Mountain region, some 65
km distant from Sudbury. The rapid acidification and fish population extinc-
tion in this sensitive region was attributed to the spread of acid deposition
from the metal smelters in Sudbury, which were emitting 2.4 million metric
tons of sulfur dioxide annually and had recently increased stack height
significantly. Increases in acidity of more that one hundredfold in the past
decade were observed in some lakes, and of 150 lakes surveyed, 33 were clas-
sified as "critically acidic" (pH less that 4.5) and 37 were described as
"endangered" (pH 4.5 - 5.5). (Beamish, 1976).
Similar effects have been observed in the Adirondack Mountains in New
York. A recent survey found that 51% of the mountain lakes (217 lakes at an
elevation above 600 m) have pH values below 5.0; 90% of these lakes contain
no fish. In contrast, during the period 1927-37, only 4% of these lakes had
a pH under 5.0 or were devoid of fish (Schofield, 1976).
The gradual disappearance of fish usually is attributed to a failure of
recruitment, and acidiwater first affects fish egg and fry. In addition,
massive kills of salmon and trout have been observediduring snow-melt and
after heavy rain. Physiological studies strongly indicate that failure in
body salt regulation is the primary cause of fish death in acid water.
Therefore, the content of dissolved salts in the water influences the acid
tolerance, and field surveys show that the fish populations disappear at a
higher pH in lakes with extremely low ion content.
Other evidence indicates that not only are fish affected by acidifica-
tion, but that a variety of other aquatic organisms in the food web are
adversely altered (Dochinger and Seliga, 1976; Braekke, 1976; Hendrey et aj.,
1976). In general, algal communities in lakes with pH under 6.0 contain
fewer species, with a shift toward more acid-tolerant forms. In particular,
the chlorophyceae (green algae) are reduced in acid lakes. Some acid lakes
and streams contain greater amounts of benthic moss (Sphagnum) and attached
algae, and the growth of rooted plants is reduced. There is a tendency
toward fewer species of aquatic invertebrates both in the water column and in
sediments in acid lakes and streams. The rate of decomposition of organic
matter is reduced, with bacteria becoming less dominant relative to fungi.
Swedish workers have observed thick fungal felts over large areas of sedi-
ments in some acidified lakes. They concluded that decreased decomposition
of organic matter on the bottom of lakes, coupled with greater abundance of
submerged mosses and fungal mats, reduces nutrient cycling from the sediments.
This in turn leads to depletion of nutrients and reduced productivity in acid
lakes.
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Acid precipitation also causes other changes in lake-water chemistry as
well. Elevated concentrations of aluminum, manganese, zinc, cadmium, lead,
copper, and nickel have frequently been observed in acidified lakes (Wright
and Gjessing, 1976; Beamish, 1976; Dickson, 1975). The abnormally high
concentrations are apparently due in part to direct deposition with precipita-
tion as well as increased release (solubility) from the sediments in acidified
lakes (Dickson, 1975; Galloway et al_., 1976; Galloway and Likens, 1977).
These heavy metals may represent a major physiological stress for various
aquatic organisms.
Effects of acid precipitation in terrestrial ecosystems
In recent years concern has been expressed that forest growth may also
be affected far away from emission sources, where the concentration of acid
in air and precipitation is lower than where acute damage and visible symptoms
occur. The rate of forest growth has declined in southern Scandinavia and in
the northeastern U.S. between 1950 and 1970, but it is not possible to state
unequivocally that this decline is caused by acid precipitation (Abrahamsen
et aJL , 1976; Dochinger and Seliga, 1976; Tamm, 1976).
Terrestrial ecosystems are very complex, with numerous living and nonliv-
ing components. Since acid precipitation is only one of many environmental
stresses, its impact may enhance, be enhanced by, or be swamped by other
factors. Recent experiments indicate that acid precipitation can damage
foliage; accelerate cuticular erosion; alter responses to associated patho-
gens, symbionts, and saprophytes; affect the germination of conifer seeds and
the establishment of seedlings; affect the availability of nitrogen in the
soil, decrease soil respiration; and increase leaching of nutrient ions from
the soil (Abrahamsen et a_L , 1976; Malmer, 1976; Tamm, 1976).
Although many of these factors might be expected to adversely affect
tree growth, it has not yet been possible to demonstrate unambiguously de-
creased tree growth in the field. However, it is possible that acid damage
might have been partly offset by the nutritional benefits gained from nitrogen
compounds commonly occurring in acid precipitation. Changes already detected
in soil processes may as yet be too small to affect plant growth.
Forests are complex. It has been shown that the nature of throughfall
(rainfall reaching the forest floor without being intercepted by the crown
canopy) and stemflow (rainfall reaching the forest floor by draining down the
trunks of trees) is affected differently by different tree species. Thus the
composition of "precipitation" reaching soil, possibly affecting soil proces-
ses and transfers to freshwater systems, could be influenced by the nature of
the tree cover.
Observations of Acid Precipitation in the Western U.S.
Precipitation in much of the west is lower in acidity than is the case
in the eastern U.S. Local deposition of acid substance may tend to neutralize
excess alkalinity in some western soils. Long-distance transport and deposi-
tion, however, will tend to increase deposition of acid substances in both
the eastern states and in the west.
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In the western United States there is increasing evidence that acidic
precipitation exists both in the vicinity of major point sources and also in
and near large urban areas. In Pasadena, California measured values of pH in
rainfall during portions of 1976 and 1977 show a range of 2.7 to 5.4 with a
weighted mean value of 3.9 (Morgan and Liljestrand, pers. comm.). This is a
pattern of acidity which is commonplace in the eastern U.S. In the San
Francisco region, pH of rainfall has similarly been measured (McColl, pers.
comm.) and the indication is that the pH is below the C02 equilibrium value
of 5.7. McColl's data show that 80% of the samples taken have a measured pH
of less than 5.2 with a range of 4.8 to 5.6 and a mean pH of 4.9. The Seattle-
Tacoma area has likewise had an acidic precipitation measured at distances
from the major S02 sources at the Tacoma Smelter and nearby refineries.
SUMMARY
Anthropogenic emissions of sulfur and nitrogen oxides appear to be major
precursors of acid-forming anions in acid precipitation. Strong acids have
lowered the pH of precipitation in the eastern United States and in much of
northern Europe to between 3 and 5.
The most startling effects discovered so far of such air pollutants,
have appeared in relatively pristine, remote areas of Norway, Sweden and the
eastern U.S. and Canada.
It is virtually impossible to foresee all the ultimate consequences of
increasing emissions. The effects on terrestrial ecosystems are often subtle
and difficult to document over the short term. Adverse effects on aquatic
systems have been reported from several countries.
As we burn ever-greater quantities of fossil fuels, we can expect the
impact of these and related air pollutants on sensitive ecosystems to become
more serious even though their overall severity still has to be evaluated.
Effects of acid precipitation and pollution in general on natural ecosystems
should be considered from a broad perspective - not only as to the present
but also toward some time in the future when possible effects may be proved
beyond doubt to be cumulative and/or become irreversible, as well as intoler-
able from socioeconomic considerations.
The National Energy Plan calls for continuing increases in the combustion
of fossil fuels and consequently for continuing increases in total emissions
to the atmosphere. For this reason, it is essential that the United States
develop and maintain an adequate national network to measure the amount,
chemical form, and geographical distribution of the deposited material and
the biological consequences of that deposition in the various regions.
Development of such a network should be an integral part of the National
Energy Plan.
23
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BIOTIC AND ABIOTIC INTERACTIONS
Reactions of an organism to an air pollutant may be altered by the
presence of other pollutants which may alter the degree and incidence of
biotic stresses. Air pollutants do not occur alone in the atmosphere; rather
they are complex emissions containing a mixture of gases and particles.
Combustion of coal, for example, results not only in the emission of large
quantities of SO and NO , but also fluorides and metals, in gaseous and
particulate forms; hydrocarbons; carbon dioxide; and a melange of other
compounds. Depending upon meteorological considerations, these emissions can
merge with those from other point or area sources. When the mixtures come
into contact with a receptor, toxic components can alter the normal processes
or organisms: One can then ask the following questions: 1) do the individual
pollutants in this mixture act on the organism independently or does the
presence of one pollutant alter the susceptibility of the host to another?
2) do air pollutants alter the susceptibility of the receptor to pathogens?
and 3) do air pollutants alter the suitability of the receptor as a habitat
for destructive insects?
Effects on the Plant-Pollutant Interactions
Only limited studies have been conducted on the effects of pollutant
mixtures on biological systems. The majority of these studies have been
limited to effects (foliar injury, growth and yield) on plant systems (Krause,
1975; Krause and Kaiser, 1977; Reinert et al., 1975). Pollutant mixtures,
for example, S02+N02; S02+03; S02+HF; NO^+HT and S02+ metals, have been
studied. Three general types of plant effects have been reported: Synergism,
where the effects of the pollutant mixture were greater than would be expected
from the sum of the effects of individual pollutants; independence, where the
pollutants acted separately to produce their effect; and antagonism, where
the presence of one compound decreased the phytotoxicity of another.
The Magnitude of the Effect
The present data are inadequate to indicate the significance of pollutant
interactions in terms of their effects on foliar injury, growth, and yield.
However, mixtures of pollutants do exist in the environment and some level of
effects probably occurs. With the projected increases in SO , NO (Figure 1)
and probably HF, the likelihood of effects from these pollutant mixtures will
increase. It is also likely that there will be increased interaction of
effluents from power generation and pollutants from urban sources which could
increase the biological effects. But based on the limited data base, the
magnitude of these effects cannot be estimated.
24
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Diseases
The effect of air pollutants in the interactions among compartments of
the biotic environment has been recognized as a significant consequence of
air pollution and may be expressed, with respect to plant diseases, as making
the host a more or less suitable habitat for the pathogen.
Information on the effects of pollutants on the plant-pathogen relation-
ship has been based upon three types of evidence: 1) field observations; 2)
experimental exposure of the host-pathogen system; and 3) studies of the
toxicity of the pollutant and the pathogen alone. Field and laboratory
observations suggest that, in general, the presence of S02 results in a
decrease in the incidence and severity of fungus diseases (Heagle, 1973;
Weinstein et al., 1975). In some cases, where a fungus infection already
exists, susceptibility to S02 may be enhanced (Chiba and Tanaka, 1968).
In the case of ozone, its effect on plant pathogens depends upon the
time of exposure to the pollutant in relation to the time of inoculation. In
general, the presence of ozone-induced and severity of certain diseases, with
exposure to ozone after inoculation often results in a lesser incidence and
severity of disease. A considerable body of evidence also exists that sug-
gests that infection by a fungus confers a measure of resistance to subsequent
ozone exposure (Treshow, 1975; Heagle, 1973; Weber, 1977). Inhibition of
nematodes in soybean roots has also been reported after exposure of the plant
to Oa alone or in combination with S02 (Weber, 1977).
t
Insects
In several geographical areas, an increased incidence of insects in
natural vegetation is associated with injury due to air pollutants. The kind
of effect that occurs in the field depends upon the characteristics of the
pollutant(s), conditions of exposure, environment, and species of plant and
insect. There are two hypotheses to explain this effect: 1) pollutants
exert a direct toxic effect on the insects and 2) pollutants change the
susceptibility or attractiveness of the plant to the insect. Oxidant pollu-
tion injury has been shown to predispose ponderosa pine to invasion by western
and mountain pine beetles (NAS, 1977). Doane (1915) described many insects
in the plume zone of the Selby smelter in California but did not relate this
incidence and severity to the occurrence of S02-
The presence of airborne particulates is known to be related to the
incidence of outbreaks of certain destructive insects (Bartlett, 1951; Edmonds,
19-73).
Areas of Uncertainty
The mechanisms by which air pollution alters the relationships among
plants, insects, and pathogens is not understood except perhaps in the case
of invasion by bark beetles of trees weakened by oxidant pollution.
25
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One cannot assign any degree of confidence to interpretations of the
many and varied observations made in the field and under controlled laboratory
conditions until there is an understanding of certain mechanisms, some of
which are given below.
1) How is the response of an organism altered by the imposition
of two or more pollutants?
2) How does an air pollutant applied to the plant influence the
relationships between plant roots, and symbiotic microflora,
pathogenic microflora, or microfauna?
3) How does an air pollutant alter the plant as a less or more
suitable host for destructive insects?
4) How do air pollutants alter the relationship between destruc-
tive insects and their parasites and predators?
5) How do air pollutants alter the plant as a host for fungal,
bacterial, viral, and mycoplasmal pathogens?
26
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ECOSYSTEM IMPACTS
Natural terrestrial ecosystems are classified in terms of their dominant
life form, namely, deciduous and coniferous forest, chaparral, desert, grass-
land and tundra, etc. The relationship of the extent of 10 natural forest
ecosystems in the United States to an estimate of the meteorological potential
for air pollution episodes has been suggested in a recent review by Miller
and McBride (1975). See figure 4.
10
40
/-BOREAL FOREST ECOSYSTEM
2-LAKE STATES FOREST ECOSYSTEM
5-EASTERN DECIDUOUS FOREST ECOSYSTEM
4-SOUTHEASTERN PINE FOREST ECOSYSTEM
5-TROPICAL FOREST ECOSYSTEM
6-WESTERN MONTANE FOREST ECOSYSTEM
7-SUBALPINE FOREST ECOSYSTEM
fl-PACIFIC COAST FOREST ECOSYSTEM
9-CALIFORNIA WOODLAND
/0-SOUTHWESTERN WOODLAND
Figure 4. isopietns or total numbers ot forecast-days or mgn meteorological
potential in a five year period (Holzworth, 1972) compared with boundaries of
ftfrest ecosystems.
The unshaded intervening areas on the map include the other natural
ecosystems (grassland, desert and chaparral) and extensive areas classed as
agroecosystems. Aquatic ecosystems, including rivers, lakes, marshes, and
coastal marine ecosystems are distributed within and around each of the
terrestrial systems.
27
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The significance of the overall effects of sulfur oxides, photochemical
oxidants, particulates, and acid precipitation on these terrestrial and
aquatic ecosystems varies widely, depending both on the regional load of
emissions and the sensitivity of the plant and animal components of each
system. Thus the pattern of projected increases in some emissions by 1985,
and decreases in others can be expected to yield major differences in regional
ecosystems.
Plant Population Responses to Lowered Photosynthesis Rates
The most obvious effect of chronic pollutant exposure in a natural
ecosystem flows from the reduced growth rates of sensitive species, including
some dominants of the primary producer level (Woodwell, 1970; National Academy
of Sciences, 1977). The latter report reviews known and anticipated direct
and indirect effects of oxidants on populations at the producer, consumer and
decomposer trophic levels. A summary report for studies in the San Bernardino
National Forest was sponsored by the Environmental Protection Agency (Miller
et a_K , 1977) which details the impact of oxidants on a western forested
ecosystem.
The pollutants described in the previous sections generally constitute
new stresses to which existing species are not pre-adapted. As the pollution-
tolerant species increase their importance in the ecosystem, changes in
succession and diversity will result (Loucks, 1972; Glass and Tingey, 1975)
as well as altered rates of biogeochemical cycling and altered rates of
energy retention.
The overall result of these processes can be summarized briefly as
follows: 1) Biotic composition of the system will continue to change until
the mix of species best adapted to the new stress sources become the dominants.
2) Associated with these changes are shifts to (i) less carbon found in
biomass; (ii) larger R/P for the system as a whole and for the major species;
(iii) fewer species, and fewer individuals of species of relatively large
biomass; (iv) more short-lived, highly productive (r-adapted or weedy) species
(Odum, 1969).
Effects on the primary producer component can have other consequences.
Studies by Schwartz et al. (1977) have shown a 10 to 20% decrease in crude
protein matter digesTTbTTity levels in western wheatgrass exposed to chronic
low levels of SOa- Western wheatgrass is one of the dominant forage grasses
in the western-plains and a significant change in protein or digestibility
can have important consequences for consumer species (including domestic
livestock) dependent on it.
The overall significance of the plant injury process is usually inter-
preted in terms of effects on the ecosystem's standing stock, i.e., the
system's "free goods" (Westman, 1977). In effect, chronic iniury may con-
strain: 1) "the direct harvest of marketable products", or 2) "the use and
appreciation of ecosystems for recreation, aesthetic enjoyment, and study"
(Westman, 1977).
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Changes in Biogeochemical Cycles
The principal perturbation of biogeochemical cycles steming from in-
creased coal utilization is through the induction of acid rain. These effects
have been reviewed in detail in a previous section and are only recapitulated
briefly here. Analyses of forest growth in southern Sweden from 1896 to 1965
showed a 2 to 7% decrease in growth between 1950 and 1965. Johnsson and
Sundberg (1972) "found no good reason for attributing (this) reduction in
growth to any cause other than acidification." In addition to the effects on
growth, the acidification can inhibit decomposition of litter from the forest
floor (Abrahamsen et a_L , 1976).
A major influence, therefore, is that nutrients can be released due to a
decrease in standing crop of dead as well as living organic matter. Acceler-
ated leaching due to acid rain could remove the nutrients from the nutrient
pool to be bound in sediments of lakes and ocean. The smaller nutrient pool
could ultimately constrain the re-development of previous biomass levels
(Woodwell, 1970).
In addition to acid rain effects, however, biogeochemical cycles are
greatly modified by the direct addition of nutrients, especially nitrogen
(Likens et al., 1977). The balance between increased leaching and increased
nitrogen addTtions will vary regionally as the magnitude of the acid rain and
NO emissions vary.
^
Impacts on Terrestrial and Aquatic Ecosystem Carbon Flux
Nitrogen and sulfur oxide deposition from air pollution is presently of
sufficient magnitude to act as a major nutrient input and modifier of nutrient
cycling in terrestrial ecosystems. Depending on geographic location roughly
half of the inputs are dry deposited and half wet deposited. Possible long-
term responses may range from fertilization to increased successional rates
due to removal of nutrient constraints. Specific impacts are likely to be
affected to the extent that the system is nutrient deficient or the cycle is
modified to produce serious nutrient losses. The response observed at specific
sites will depend on local characteristics of the soils.
For aquatic ecosystems, the following step damage functions may be used
to describe general impacts associated with lake acidification (G.R. Hendrey
personal communication);
1. Long-term changes of less than 0.5 pH unit in the range 8.0 -
6.0 are likely to alter the biotic composition of fresh waters
to some degree. Probably no significant changes.
2. A decrease of 0.5 - 0.9 pH unit in the range 8.0-6.0 may
cause detectable alterations in community composition. Produc-
tivity of competing species will vary. Some species will be
eliminated.
29
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3. Decreasing pH from 6.0 to 5.5 will cause a reduction of species
numbers. Among remaining species, significant alterations in
ability to withstand stress will occur.
4. Below pH 5.0 - many species will be eliminated. Molluscs,
amphipods, most mayfly and many stonefly species. Several
tolerant invertebrates will become abundant. (Siolis,
notoneclan. corixials, chironomis).
5. Below pH 4.5, all of the above changes are exacerbated and all
fishes are eliminated.
Reductions in pH reduce bacterial activities and bacterial abundance/unit
organic matter. Also, phycomycetes replace bacteria as the dominant sapro-
trophs. Mineralization is greatly retarded and organic debris accumulates.
An additional influence of dry and wet deposition of oxides of sulfur
and nitrogen on aquatic ecosystems is the eutrophication that can result from
the input of these materials as nutrients in both freshwater and marine
systems. Most freshwater ecosystems are phosphorus limited, but some are
nitrogen limited, at least seasonally (Miller, et al., 1974; Schindler,
1977). Many marine and estuarine ecosystems are nTErogen limited (Ryther and
Dunstan, 1971). Increased deposition of nitrogen due to fossil fuel combus-
tion will generally not have large effects on lake productivity unless this
is accompanied by increased phosphorus loading or unless the lake is nitrogen
limited. However, because of ever increasing human population and consequent
increases in phosphorus output from sewage treatment plants, the potential
for nitrogen limited bodies of water will probably be greater in the future
than it is now. Oligotrophic lakes are likely to be the most vulnerable to
nutrient inputs from wet and dry deposition per unit of loading than are more
eutrophic lakes and can, therefore, be considered more sensitive.
Discussion of Overall Effects
The long-term consequences of stresses on ecosystems have been briefly
summarized by Loucks (1972). Analyses have now been completed that show the
results of whole-system upsets and the types of evidence needed to document
them. Harrison et ah (1970) used systems methods and the results of studies
of DDT effects on populations to examine whole ecosystem response characteris-
tics. These upsets may cause large-scale changes in population levels of
certain species and their replacement by other species, or their complete
elimination. Both studies indicate a trend toward simplification of the
system when placed under the stress of a contaminant, but the long-range
effects of such simplification cannot yet be fully evaluated.
Further work is needed on examples of potential ecosystem perturbations
on the role of native species diversity in maintaining the stability of these
systems and of the long-range effects of the trend toward simplification.
Although lichens and bryophytes have been regarded as very sensitive
components, initial effects may be manifest in the dominant and codominant
30
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trees as the canopy starts to decline in growth and vigor owing to its expo-
sure to a greater pollution flux. When exposures of sufficient magnitude
have occurred, successive layers of vegetation are removed resulting in its
most drastic effect, barren soil and erosion (Rennie and Halstead, 1977).
An approximate indication of the level of knowledge concerning important
processes common to the ecosystems shown in Figure 4 is shown in Table 1.
TABLE 1. ESTIMATES OF THE PRESENT BREADTH OF KNOWLEDGE CONCERNING
MAINLY POLLUTANT INDUCED PERTURBATIONS IN ECOSYSTEMS.
Changes Ecosystem
Forest
Grassland Conifer Deciduous Chaparral Desert
Primary Productivity + ++ + ? ?
Reproductive Capacity + +0 ? ?
t
Host-Parasite
Relationships 0 ++ + 00
Litter Decay 0 +0 00
Nutrient Storage + + ++ 00
Successional Patterns 0 + + ? ?
Animal Morbidity
and Mortality 0 ? 0 00
0 = no knowledge of effects
? = probable effects
+ .= limited knowledge
++ = substantial knowledge
Single and double plus signs have been assigned where first approximation
simulation models are now available to study the effects of chronic oxidant
exposure. Obviously, gaps in the table are more profound than apparent
knowledge.
31
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During the last 20 to 30 years, the problem of elevated photochemical
oxidant concentrations has become a new stress in several ecosystems particu-
larly in the Southwest. Plant and animal communities in natural ecosystems
have evolved over thousands of years in the presence of periodic stresses
(droughts) and catastrophic events (fire). Over this time span, certain
species have developed successful mechanisms for survival so that successional
development toward a stable climax community may resume its course. In a
western mixed conifer forest ecosystem, when oxida'nt stress is superimposed
on the natural stresses (drought and fire) the course of developemnt in some
forest stands appears to be a rapid decline in the population of the most
fire tolerant species, ponderosa and Jeffrey pines. It is possible that
repeated fire events could inhibit the recovery of the stands because the
remaining oxidant tolerant but fire sensitive species may be nearly eliminated
in just a few decades. The former forest cover may yield to a less desirable
grass or shrub cover.
It is clear that oxidant pollution can affect ecosystems by adversely
influencing the nitrogen fixation process and in other ways as well (Taylor
and Miller, 1973; Miller and McBride, 1975). SO , as shown above, also
influences nitrogen fixation but, as with oxidant pollution, affects a number
of other ecosystem processes in addition.
Oxidant air pollution and SO emissions are the major air pollutants
from transportation-oriented and stationary sources, respectively. In the
western United States, the preponderant air pollution problem is associated
with oxidants. In the eastern United States, the dominating forms of air
pollution are SO , NO , and oxidant. Ecosystems in all parts of the country
are being affected in one way or another by these two types of air pollution
emissions due to long distance transport. The mechanisms whereby air pollu-
tants exert an impact on natural and man-made or managed ecosystems are
numerous, but most mechanisms are related to photosynthesis or changing
community structure and at this point are too poorly understood to make
definitive forecasts of consequences of increased coal utilization.
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EFFECTS ON MATERIALS
The damaging effects of air pollution on a wide variety of materials
have been recognized for many decades. Sulfur oxides, nitrogen oxides, and
particulate matter are the pollutants emitted by coal-burning facilities and
known to damage materials. Estimates indicate that sulfur oxides cause about
35 percent of the total damage to materials. For example, atmospheric S02
and its derivatives can 1) accelerate the corrosion rates of most ferrous
metals and some non-ferrous metals, mainly zinc galvanized products; 2)
reduce the durability of exterior paints containing calcium carbonate fillers;
3) attack and cause pitting in limestone, marble, mortar, and concrete build-
ing materials; 4) deteriorate cellulosic and some man-made textile fibers; 5)
produce color changes in some textile dyes; and 6) cause paper and leather
products to lose strength, a potentially serious problem for some urban
museums and libraries.
Oxides of nitrogen (mainly NOa) and subsequent reaction products (nitric
acid and nitrates) can cause certain textile dyes to fade and some textile
additives to yellow, deteriorate cellulosic fabrics, and accelerate stress
corrosion of certain metal alloys. In assessing NO damage to materials,
however, one must not lose sight of the role that NO plays in the photochem-
ical formation and buildup of ozone and other oxidants, as well as in the
photo-oxidation of SOa aerosols. These photochemical reaction products are
believed to cause more damage than those associated directly with NOX.
The most obvious effect of airborne particles is the soiling of property-
buildings, homes, automobiles, etc. Soiling generally produces a need for
more frequent cleaning and/or painting, thus resulting in an economic burden.
Certain kinds of particles can also cause direct chemical damage to materials
because of corrosive chemicals sorbed by the particulates. Sulfuric acid in
the form of liquid aerosols or attached to fly ash particulates is well known
to cause damage to paint and structural materials in the vicinity of some oil
and coal-fired power plants.
Meteorological factors strongly influence the rate that pollutants
damage materials. Important factors are relative humidity, temperature,
rainfall, sunlight and air movement. Relative humidity is the most important;
damage can be significantly greater in more humid (> 60% RH) areas than in
drier areas.
In attempting to estimate the cost of the material damage attributed to
air pollution, economists recognize the complexities of developing meaningful
cost figures mainly because information gaps exist in two broad areas: (1)
inadequate damage function or effects data on economically important material
33
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receptors, and (2) a general lack of information on the spatial and temporal
distribution of pollutant levels and receptor populations. Nevertheless, a
number of gross damage estimates have been made. Comparative studies made in
polluted and nonpolluted areas have highlighted the corrosion effects of
sulfur dioxide on materials. The role of acid precipitation has not yet been
clarified. In 1970 the annual costs per person of damage ascribable to the
main atmospheric sulfur pollutants were estimated to be about $7 and $4 in
the the USA and Sweden, respectively (Kucera, 1976). The most recent estimate
for material losses in 1970 (excluding soiling costs) was $1.7 billion per
year. This figure was largely arrived at by summing previous damage estimates
for specific material categories. A breakdown of this figure shows that $0.6
billion was attributed to SO , $0.9 billion to the combined effect of NO and
oxidants, and $0.2 billion to particulate matter. Paint and zinc (galvanized
products), mainly because of the large total surface area exposed to the
outdoors, are the most vulnerable materials from an economic standpoint.
However, certain test methods such' as painted panels and losses of textiles
may be excessive because physical damage functions are in error. Therefore,
economic losses may not be as high as the $1.7 billion.
Because of the information gaps, reliable estimates of the incremental
economic impact on materials resulting from increased consumption of coal
specifically is not possible. Gillette (who has written an assessment of the
costs of S02 damage to materials) estimates that a 10 percent increase in
overall levels of urban air pollution would probably increase the economic
material loss by 20-30 percent, whereas a 25 percent increase in air pollution
would probably more than double these losses.
Gillette (1975) points out, however, that any estimate must be qualified
because materials have pollutant threshold levels below which economic damage
does not occur. Threshold levels are based on the premise that, while some
materials may have an infinite life under ideal environmental conditions,
manufactured products have a finite expected service life mainly because of
obsolescence. If the actual use life of a product is less than its normal or
ordinary use life because of damage by pollution, an economic loss has occurred.
These losses are reflected in the market in the form of increased expenditures
for replacement or maintenance.
There are four areas in the economic functions which would add an error
margin of possibly a factor of 2 to 3 to existing estimates.
1. Present techniques do not reflect the introduction into the
market place of highly resistant materials (acrylics, other
polymers, self-weathering steels, aluminum clad steels).
2. Estimates assume that galvanized steels are left uncoated.
This is not the case. Therefore, the amount of surface which
is highly suspectible to damage is greatly reduced.
3. Many materials have use lives which are so short, that pollut-
ant damage has little effect on them. In some cases, the item
is used regardless of rusting as long as it functions.
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Present loss estimates assume that a substitute material costs
more than the original material, the cost differential is
attributed to pollution. Due to the increasing cost of labor,
materials are being sought which reduce maintenance, and at
the same time are resistant to pollutant attack. Savings
realized from lower maintenance should be deducted from the
costs charged to pollution.
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EFFECTS ON VISIBILITY
Visibility reduction is probably the most immediate and obvious effect
of air pollution, and is the best understood and most easily quantified
effect of pollution by fine particulate. Visibility can be simply defined as
the farthest distance at which an unaided human eye can see a black object
located at the horizon. In an atmosphere completely free of particulate
contaminants, the visibility is limited to about 200 km due to the scattering
of light by gases composing the atmosphere. In actuality aerosols exist
throughout the atmosphere and scatter additional light, reducing the visibil-
ity in some places to appreciably shorter distances. Visibilities in the
western United States often approach the limit of 200 km, and 100 km is
attained regularly in noncloudy, rural settings. Public Law 95-95 requiring
nondegradation of visibility in federal class I regions has elevated the
importance of this problem, mainly to protect scenic vistas. PL 95-95 also
protects class I areas from further ecological damage as well.
Our knowledge of the causes and characteristics of visibility reducing
aerosols has increased greatly in the past ten years. One of the most signif-
icant realizations has been that aerosols between the sizes of 0.1 and 1.0 urn
are responsible for a majority of the visibility reduction (Waggoner and
Charlson, 1977). This fact results from two phenomena: first, particles
smaller than 0.1 urn, though present in very high number, are very inefficient
in scattering light and thus contribute very little to visibility reduction;
second, particles larger than about 1.0 urn, are both inefficient in scattering
light, and usually exist in quite small numbers and contribute to only a
small fraction of the visibility reduction (except in dust storms and fog).
Thousands of measurements of atmospheric aerosol size distributions have
shown that on a mass, volume, or surface basis the aerosol exists in up to
three distinct size modes: nuclei (< 0.1 urn diameter), accumulation (0.1 urn
to 2.0 urn), and coarse particle (> 2.0 urn). The number of modes, mean diame-
ter, and the mass, volume, or surface in each mode depend upon the source and
history of the aerosol. Coarse particles consist of windblown dust, fly ash,
plant parts, powders from any grinding or pulverizing operation and activated
clouds and fog drops. They are removed by sedimentation and precipitation
and have little interaction with fine particles. The nuclei mode originates
mainly from the condensation of hot, supersaturated vapors during combustion
processes. It loses particles primarily by coagulation to larger sizes.
Accumulation mode particles are formed by the coagulation of smaller particles,
by the condensation of vapors onto existing smaller particles, and by the
chemical reaction of vapors with existing smaller particles. Coagulation is
not a major removal mechanism for aerosols of accumulation mode size because
of the rapid decrease on number concentration in that size range (Higgins,
1977).
36
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Because aerosols in the 0.1 to 1.0 urn range are responsible for most
visibility reduction and because fine particles tend to accumulate in that
same range, it follows that to control visibility reduction one must control
the entry of particles into the accumulation mode. The composition of accumu-
lation mode aerosol has therefore been the subject of much recent research.
Current evidence is that sulfate often accounts for about half of the accumu-
lation mode mass, for example in industrial regions. The most direct evidence
has been measurement of sulfur and sulfate by x-ray fluorescence and wet-
chemical methods (Stevens, 1978). Supporting evidence comes from the humidi-
fied nephelometer work of Waggoner, (Waggoner and Charlson, 1977) in which
water vapor is added to ambient aerosol and the light scattering is measured;
increases in light scattering characteristic of various sulfate aerosols were
found during field studies in Missouri, Michigan, and Arkansas (Weiss, 1977).
Further evidence is given by the regression analyses of Trijonis (Trijonis
and Yuan, 1977), Barone (Barone, In press), and Cass (Cass, 1976). Though
regressions do not necessarily imply cause-and-effect relationships, a lack
of correlation between visibility reduction and sulfate would imply no
cause-and-effect; in these studies definite correlations exist. Another
study implicating the visibility reduction sulfate link is Trijonis1 analysis
(Trijonis and Yuan, 1977) of the southwest U.S. copper strike of 1967-1968.
During the strike copper smelters were shut down for nine months and resulting
NASN sulfate levels were 38 to 76% below seasonal averages of surrounding
years. At the same time airport visibility measurements improved by 5 to
25%.
It is significant that simultaneous, direct measurements of optical and
concentration data agree, with a ratio of sulfate mass concentration to
extinctions of ca 0.1 g/m2. The simultaneous agreement of these two approaches
and with computations by Waggoner et a_L , 1976 lend credibility to all these
approaches.
The origin of anthropogenic sulfate in the accumulation mode is sulfur
dioxide which has been converted by any of several possible atmospheric
reactions. Recent regional-scale field studies by the U.S.E.P.A. indicate
that S02 to sulfate conversion rates in power plant plumes can account for
significant sulfate formation, as well as transport many hundreds of kilome-
ters downwind (Wilson, 1977). Thus, even if large sources of sulfur dioxide
were to be located in rural areas, urban as well as rural sulfate levels
could be expected to increase, accompanied by reduced visibility.
In regions prone to high relative humidities three phenomena may aggra-
vate.the sulfur dioxide-sulfate-visibility relationship. First, there is an
increased conversion rate of sulfur dioxide to sulfate, (Eggleton and Cox, In
press; Beilke and Gravenhorst, In press) thus, more net sulfate may be formic!
due to the reduced opportunity Tor S02 removal by dry deposition. Second,
the visibility reduction of a sulfate aerosol always increases as the relative
humidity increases because the particles grow in size (Covert, 1972). The
visibiltiy reduction of some sulfate species (acid sulfates, such as sulfuric
acid) increases smoothly with increasing humidity; other species (e.g. ammon-
ium sulfate) exhibit sudden particle size growth at certain humidities and
double or triple their visibility reduction above those humidities. Third,
37
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when particles of certain sulfate species (e.g. ammonium sulfate) have grown
suddenly because of sufficiently high humidity, they do not return to their
former size as the humidity falls below that same critical value (Yamamoto,
1975); thus, the visibility reduction persists until a lower humidity is
reached. However, the frequent existence of RH < 70% (below 70% these effects
become quantitatively unimportant) in areas such as most of the western half
of the U.S. allows useful simplification. Even at 80% RH, the effect is only
about a factor of two above low RH values.
The impact of increased coal usage on visibility thus depends on the
control of sulfur dioxide emissions. If sulfur dioxide emissions cannot be
kept at present-day values, rural and urban sulfate levels can be expected to
increase, with a further visibility reduction. The effects of further visi-
bility reduction fall into two broad categories: social-political effects
and climate modification. Social-political effects range from simple citizen
dissatisfaction to decrease in revenue and property values in area of scenic
attraction. Potential climatological effects include the reduction of solar
radiation for photosynthesis and energy production, heating or cooling of the
atmosphere resulting in changes in the length of growing seasons, and changing
precipitation levels (Higgins, 1977).
38
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REFERENCES
Abrahamsen, G., K. Bjor, Ro Horntvedt, and B. Tveite. 1976. Effects of acid
precipitation on coniferous forest, pp. 37-63 In: Research Report FR-6.
F.H. Braekke, ed. SNSF Project, NISK, As, Norway.
Aimer, B., C. Ekstrom, E. Hornstorm, and V. Miller. 1974. Effects of acid-
ification of Swedish lakes. Ambio 3, 30-36.
Andren, A.W., D.H. Klein, and Y. Talmi. 1975. Selenium in coal-fired stream
plant emission. Environ. Sci. Techno!. 9:856-858,
Bartlett, B.R. 1951. The action of certain "inert" dust materials on hymen-
optera. J. Econ. Entomol. 44:891-896.
Barone, J. Visibility Reduction Characteristic of Three Cities in California,
to be submitted to Atmospheric Environment. January, 1978.
' i
Beamish, R.J. 1976. Acidification of lakes in Canada by acid precipitation
and the resulting effects on fishes, pp. 479-498. In: Proc. The
First Internat. Symp. on Acid Precipitation and the Forest Ecosystem.
L.S. Dochinger and T.A. Seling, eds. U.S.D.A. Forest Service Gen. Tech.
Report NE-23.
Beilke, S. , and G. Gravenhorst. Heterogeneous SO-Oxidation in the Droplet
Phase, to be published in Atmospheric Environment, January, 1978.
Benedict, H.M., C.J. Miller, and R.E. Olson. 1971. Economic Impact of Air
Pollutants on Plants in the United States. Final Report on Project LSD-
1056. Stanford Research Institute, Menlo Park, CA. 77 pp.
Berry, C.R., and L.A. Ripperton. 1963. Ozone, A Possible Cause of White Pine
Emergence Tipburn. Phytopathology 53:552-557.
Berry, W.L., and A. Wallace. 1974. Trace elements in the environment - their
role and potential toxicity as related to fossil fuels. A preliminary
study. UCLA 12-946. Univ. Calif., Los Angeles.
Blumenthal, D.L., W.H. White, R.L. Peace, and T.B. Smith. 1974. Determina-
tion of the feasibility of the long-range transport of ozone or ozone
precursors. U.S. EPA-450/3-74-061 92 pp.
Bond, H., B. Lighthart, R. Shimabuku, and L. Russell. 1976. Some Effects of
Cadmium On Coniferous Soil and Litter Microcosms. Soil Sci. 121(5):
278-287.
39
-------
Braekke, F.H. 1976. Impact of acid precipitation of forest and freshwater
ecosystems in Norway. Research Report No. 6. Acid Precipitation on
forests and fish. Aas, Norway, lllp.
Cass, G.R. 1976. The Relationship Between Sulfate Air Quality and Visibility
as Los Angeles, EQL Memo #18, Pasadena: California Institute of
Technology.
Chamberlain, A.C. 1967. Deposition of particles to natural surfaces. In:
Airborne Microbes. 17th Symposium Soc. of Gen. Microb. Ed: Gregory,
Monteith. Cambridge Press, London, pp. 138-164.
Chiba, 0., and K. Tanaka. 1968. The effect of sulfur dioxide on the develop-
ment of pine needle blight caused by Rhizosphaera (1). J. Jap. Forestry
Soc. 50: 135-139.
Cogbill, C.V., and G.E. Likens. 1974. Acid precipitation in northwestern
United States. Water Resources Research 10: 1133-1137.
Costonis, A.C., and W.A. Sinclair. 1969. Relationships of atmospheric ozone
to needle blight of eastern white pine. Phytopathology 59: 1566-1574.
Covert, D.S. 1972. A Study of the Relationship of Chemical Composition and
Humidity to Light Scattering by Aerosols. J. Applied Meteorology, II,
pp. 968-976.
Crecelius, E.A., L.A. Rancitelli, K.A. Abel, R.L. McKeever, and S.R. Garcia.
1977. Air Quality and Power Plant Effluents Report. Col strip Midyear
Report. PNW. Richland, WA. 14 pp.
Czaja, A.T. 1966. The effect of dust, especially cement dust, upon plants.
Agnew. Bot. 40: 106-120.
Darley, E.F. 1966. Studies on the effect of cement kiln dust on vegetation.
J. Air Pollut. Contr. Assoc. 16:L 145-150.
Davis, D.D., G. Smith, and G. Glauber. 1974. Trace gas analysis of power
plant plumes via aircraft measurement: 03, NO , S02 chemistry. Science
186: 733-736. X
de Cormis, L. 1969. Quelques aspects de 1'absorption du soufre par les
plantes soumises a une atmosphere contenant du S02. Proc. Eur. Congr.
Air Pollut., 1st, 1968, pp. 75-78.
Dickson, W. 1975. Institute of Freshwater Research, Drottningholm, Sweden,
Report No. 54, 8.
Doane, R.W. 1915. Insect pests in the Selby smoke zone. Bull, U.S. Bur.
Mines No. 98. pp. 428-521.
40
-------
Dochinger, L.S. and T.A. Seliga. 1976a. Proceedings First International
Symposium on Acid Precipitation and the Forest Ecosystem. USDA Forest
Service, Gen. Tech. Rept. NE-23, Northeast. For. Exp. Sta., Upper Darby,
Pa. 1079 pp.
Dochinger, L.S., and T.A. Seliga. 1976b. Workshop report on acid precipita-
tion and the forest ecosystem. USDA Forest Service, Gen. Tech. Rept.
NE-26 Northeast. For. Exp. Sta., Upper Darby, Pa. 18 pp.
Edinger, J.G. 1973. Vertical distribution of photochemical smog in the Los
Angeles basin. Environ. Sci. Technol. 7:247-252.
Edmonds, G.F., Jr. 1973. Ecology of the black pineleaf scale (Homoptera:
Diaspididae). Environ. Entomol. 2:765-777.
Eggleton, A.E.J., and R.A. Cox. Homogeneous Oxidation of Sulphur Compounds in
the Atmosphere, to be published in Atmospheric Environment, January,
1978.
EPA. 1971. Air Quality Criteria for Nitrogen Oxides. Air Pollution Control
Office Pub. No. AP-84, Washington, D.C.
EPA. 1973. Effects of Sulfur Oxides in the Atmosphere on Vegetation. EPA
Ecological Research Series. EPA-R3-73-030. September 1973. 43 pp.
EPRI. 1976. Sulfur Oxides: Current Status of Knowledge. EPRI Research
Project 681-1, Final Report, December 1976.
Galloway, J.N., and E. Cowling. 1977. The effects of acid precipitation on
aquatic and terrestrial ecosystems: A proposed precipitation chemistry
network. J. Air Pollut. Control Assoc. (In Press)
Galloway, J.N., and G.E. Likens. 1977. Atmospheric enhancement of metal
deposition in Adirondack lake sediments. Research Project Tech. Comple-
tion Report, Project No. A-067-NY, Report to the Office of Water Resour-
ces Research, Department of the Interior, Washington, D.C. July 1977.
40 pp.
Galloway, J.N., G.E. Likens, and E.S. Edgerton. 1976. Acid precipitation in
the northeastern United States: pH and acidity. Science 194:722-724.
Galloway, J.N., C.L. Schofield, E. Yost, and G.E. Likens. 1976. Influences
-of acid precipitation on the water and sediment geochemistry of Adirondack
mountain lakes. Abstracts of Papers Submitted for the 39th Annual
Meeting of the American Society of Limnology and Oceanography. Savannah,
Georgia.
Ghiorse, W.C., and M. Alexander. 1976. Effect of microorganisms on the
sorption and fate of sulfur dioxide and nitrogen dioxide in soil. J.
Environ. Qual. 5:227-230.
41
-------
Gillette, Donald G. 1975. Sulfur Dioxide and Material Damage. APCA Journal,
Vol. 25, No. 12:1238-1243 (revision of paper N 74-170, APCA, 1974).
Gjessing, E.T., A. Henriksen, M. Johannessen, and R.F. Wright. 1976. Impact
of Acid Precipitation on Forest and Freshwater Ecosystems in Norway.
SNSF Project Report FR 6/76, Aas-NLH, Norway.
Glass, N.R. , A.S. Lefohn, D.E. Weber, and K.A. Buell. 1977. The Need for
Flue Gas Desulfurization (FGD): Ecological Effects of Air Pollutants.
In: The Status of Flue Gas Desulfurization Applications in the United
States: A Technology Assessment. Federal Power Commission Report.
July 1977. pp. 11-52 - 11-72.
Glass, N.R. , and D. Tingey. 1975. Effects of Air Pollution on Ecological
Processes. In: Radiation Research: Biomedical, Chemical, and Physical
Perspectives. Ed. Nygaard, Adler, and Sinclair. Academic Press.
Guderian, R. 1977. Air Pollution: Phytotoxicity of Acidic Gases and Its
Significance in Air Pollution Control. Ecological Studies Ser. 22
Springer-Verlag, New York. 127 pp.
Halstead, R.L., and P.J. Rennie. 1977. The effects of sulphur on soils in
Canada, p. 181-219. In: Sulphur and Its Inorganic Derivatives in the
Canadian Environment. National Research Council, Environmental Secretar-
iat, Publication No. NRCC 15015. Ottawa.
Harrison, H.L., O.L. Loucks, J.W. Mitchell, D.F. Parkhurst, C.R. Tracy, D.G.
Walts, and V.J. Yamacone Jr. 1970. Systems Studies of DDT Transport.
Science 1970:503-508.
Heagle, A.S. 1973. Interactions between air pollutants and plant parasites.
Ann. Rev. Phytopath. 11:365-388.
Heggestad, H.E. 1966. Ozone as a tobacco toxicant. J. Air Poll. Cont.
Assoc. 11:691-694.
Hegg, D., P.V. Hobbs, L.F. Radke and H. Harrison. 1977. Ozone and nitrogen
oxides in power plant plumes. Intern. Conf. on Photochem. Ox. Pollut.
and Control, Proceed. I: 173-183.
Helmke, P.A., E.M. Larsen, W.P. Robarge, R.D. Koons, J. Thresher, and M.
Schoenfield. 1976. Trace Elements. In: Documentation of Environmental
Change Related to the Columbia Electric Generating Station. 9th Semian-
nual Rept., pp. 171-183. IES Rept. No. 69. Univ. Wise.
Helmke, P.A., W. Robarge, M. Schoenfield, and John Thresher. 1977. Trace
Elements. In: Documentation of Environmental Change Related to the
Columbia Generating Station. Tenth Semiannual Report, pp. 232-237. IES
Report 82. University of Wisconsin.
42
-------
Hendrey, G.R., K. Baalsrud, T.S. Traaen, M. Laake, and G. Raddum. 1976.
Acid precipitation: some hydrogeological changes. Ambio 5(5-6):224-
227.
HEW. 1970. Air Quality Criteria for Sulfur Oxides, U.S. Dept. HEW., NAPCA
Publication No. A-50.
Higgins, I.T.T. 1977. Airborne Particles, Washington, D.C.: National
Academy of Sciences.
Hill, A.C. 1971. Vegetation: A sink for atmospheric pollutants. J. Air
Poll. Contr. Assoc. 21:341-346.
Hine, C.H., D. Meyers, and R.W. Wright. 1970. Pulmonary changes in animals
exposed to nitrogen dioxide, effects of acute exposures. Toxicol. Appl.
Pharmacol. 16:201-213.
Holzworth, G.C. 1972. Mixing ir-ight, wind speed, and potential for urban
air pollution throughout the contiguous United States. EPA Publ. AP-
101.
Ingold, C.T. 1971. Fungal spores. Clarendon Press. Oxford, 302. pp.
Jacobson, J.S. 1977. The effects of photochemical oxidants on vegetation.
VDI - Bericht NR. 270:163-173.
Jacobson, J.S., and A.C. Hill. 1970. Recognition of Air Pollution Injury to
Vegetation: A Pictorial Atlas. Air Pollut. Cont. Assoc., Pittsburg,
Pa.
Jones, P.W., R.D. Giammar, P.E. Strip, andT.B. Stanford. 1976. Efficient
collection of polycyclic organic compounds from combustion effluents.
Environ. Sci. Technol. 10:806-810.
Johnsson, B., and R. Sundberg. 1972. Has the acidification by atmospheric
pollution caused a growth reduction in Swedish forests? Research Note
No. 20. Department of Forest Yield Research, Royal College of Forestry,
Stockholm, Sweden. 48 pp.
Jordan, M.J. 1975. Effects of zinc smelter emissions and fire on a chestnut-
oak woodland. Ecology 56:78-91.
Krause, G.H.M. 1975. Phytotoxische wechsel wirkungen zuischen schweteldiox-
ide and den schwermetallen zink and cadmium. Schriftenriehe Landes.
Immiss Bodennutz. 34:86-91.
Krause, G.H.M., and H. Kaiser. 1977. Plant responses to heavy metals and
sulfur dioxide. Environ. Pollution. 12:63-71.
Kucera, V. 1976. Effects of sulfur dioxide and acid precipitation on metals
and anti-rust painted steel. Ambio 5(5-6):243-248.
43
-------
Lech, J.J., and M. Melancom. 1977. Hazardous Chemicals in Fish. In:
Documentation of Environmental Change Related to the Columbia Generating
Station. Tenth Semiannual Report, pp. 132-142. IES Report 82. Univer-
sity of Wisconsin.
Lerman, S.L., and E.F. Darley. 1975. Particulates. In: Responses of
Plants to Air Pollution. J.B. Mudd and T.T. Kozlowski, eds. Academic
Press, N.Y. pp. 141-158.
Lighthart, B., and H. Bond. 1976. Design and Preliminary Results of Soil
Litter Microcosms. Int. J. Env. St. 10:51-58.
Likens, G.E., 1976. Acid precipitation. Chemical and Engineering News.
54:29-44.
Likens, G.E., and F.H. Bormann. 1974. Acid Rain: a serious regional environ-
mental problem. Science 184:1176-1179.
Likens, G.E. and F.H. Bormann. 1975. Acidity in rainwater: Has an explana-
tion been presented? Science 188:957-958.
Likens, G.E., F.H. Borman, R.S. Pierce, J.S. Eaton, and N.M. Johnson. 1977.
Biogeochemistry of a forested ecosystem. Springer-Verlag, New York.
Linton, R.W., A. Loh, and D.F.S. Natusch. 1976. Surface predominance of
trace elements in airborne particles. Science 191:852-854.
Loucks, O.L. 1972. Contaminants and Recycling in Relation to Biogeochemical
Cycles. In: Challenging Biological Problems. I.A. Behnke ,ed. Oxford
Univ. Press. New York.
Lunde, G. 1976. Long-range Aerial Transmission of Organic Micropollutants.
Ambio. 5:207-208.
Lunde, G., J. Gether, N. Gjos, and M.B.S. Lande. 1976. Organic Micropollu-
tants in Precipitation in Norway. SNSF Project, Norwegian Central Inst.
for Industrial Research. Fagrapport 9. Oslo.
MacLean, D.C. 1975. Stickstoffoxide als phytotoxische Luftverunreinigungen.
Staub-Reinhalt. Luft. 35:205-210.
*
Male, L.M., J. Van Sickle, and R. Wilhour. 1977. Time Series Experiments:
Experimental Methods for studying plant growth responses to air pollution.
^n Press. EPA Ecological Research Series.
Malmer, Nils. 1976. Acid precipitation: Chemical changes in the soil.
Ambio 5:231-234.
McColl, John. Department of Soils, University of California, Berkeley,
California.
44
-------
Middleton, J.T., J.B. Kendrick Jr., and H.W. Schwalm. 1950. Injury to
herbaceous plants by smog or air pollution. Plant Disease Reporter.
34:3451252.
Middleton, J.T. , L.D. Emik, and O.C. Taylor. 1956. Air quality criteria and
standards for agriculture. J. Air Pollution Control Assoc. 15:476-480.
Millecan, A.A. 1976. A survey and assessment of air pollution damage to
California vegetation 1970 through 1974. State of California, Department
of Food and Agriculture, Sacramento: 48 pp.
Miller, P.R., and A.A. Millecan. 1971. Extent of oxidant air pollution
damage to some pines and other conifers in California. Plant Diseases
Report 55:555-559.
Miller, P.R. 1973. Oxidant-induced community change in a mixed conifer
forest. Adv. Chem. Ser. 122:101-117.
Miller, P.R., and S. Rich. 1968. Ozone damage on apples. Plant Disease
Reporter 52:730-731.
Miller, P.R., and J.R., McBride. 1975. Effects of air pollutants on forest.
In: Responses of Plants to Air Pollution. J.B. Mudd, ed. Adademic
Press, pp. 195-235.
I
Miller, P.R., R.N. Kickert, O.C. Taylor, R.J. Arkeley, F.W. Cobb, Jr., D.L.
Dahlsten, P.J. Gersper, R.F. Luch, J.R. McBride, J.R. Partneter, Jr.,
J.M. Wenz, M. White and W.W. Wilcox. 1977. Photochemical oxidant air
pollutant effects on a mixed conifer forest ecosystem - A progress
report. U.S. Environmental Research Laboratory, 338 pp.
Miller, W.E., T.E. Maloney, and J.C. Greene. 1974. Algal productivity in 49
lake waters as determined by algal assays. Water Research, Vol. 8:667-
679.
Morgan, J., and Liljestrand. 1977. Personal communication with N. Glass.
Morris, C.L. 1973. Ozone damage to eastern white pine in West Virginia.
Virginia Div. Forest, Forest pest Survey.
MITRE CORPORATION. 1977. Annual environment analysis report: An environmen-
•tal analysis of energy technologies using the assumptions of the National
Energy Plan. Volume I. Technical Summary. Mitre Corporation Report
MTR-7626. Washington, D.C. 91 pp.
National Academy of Sciences. 1977. Airborne particles. NRC. Washington,
D.C.
National Academy of Sciences. 1977. Medical and Biological Effects of
Environmental Pollutants: Nitrogen Oxides. NRC. Washington, D.C.
45
-------
National Academy of Sciences. 1977. Ozone and other photochemical oxidants.
NRC. Washington, D.C.
Natusch, D.F.S. 1975. Characterization of atmospheric pollutants from power
plants. Proc. 2nd Federal Conf. on the Great Lakes. J.S. Marshall,
ed. pp. 114-129.
Natusch, D.F.S., J.R. Wallace, and C.A. Evans. 1974. Toxic trace elements:
Preferential concentrations in respirable particles. Science 183:202-
204.
Natusch, D.F.S. and J.R. Wallace. 1974. Urban aerosol toxicity: The influ-
ence of particle size. Science 186: 695-699.
Odum, E.P. 1969. Strategy of Ecosystem Development. Science 164: 262-270.
Pellizzari, E.D., J.E. Bunch, B.H. Carpenter, and E. Sawick. 1975. Collec-
tion and analysis of trace organic vapor pollutants in ambient atmo-
spheres. Environ. Sci. Technol. 9: 552-555.
Reinert, R.A., A.S. Heagle, and W.W. Heck. 1975. Plant responses to pollu-
tant combinations. In: Responses of Plants to Air Pollution. J.B.
Mudd and T.T Kozlowski, eds. Academic Press, N.Y. pp. 159-177.
Rennie, P.J., and R.L. Halstead. 1977. The effects of sulphur on plants in
Canada, p. 69-179. In: Sulphur and Its Inorganic Derivatives in the
Canadian Environment. National Research Council, Environmental Secretar-
iat, Publication No. NRCC 15015. Ottawa.
Ricks, G.R., and R.J.H. Williams. 1974. Effects of atmospheric pollution on
deciduous woodland. 2. Effects of particulate matter upon stomatal
diffusion resistance in leaves of Quercus patraea (Matt.) Liebe. Environ.
Pollut. 6: 87-109.
Ripperton, L.A., J.J.B. Worth, F.M. Vukovich, and C.E. Decker. 1977. Research
Triangle Institute studies of high ozone concentrations in nonurban areas.
Internat. Conf. on Photochem. Ox. Pollution and Control. I: 413-424.
Ryther, J.H., and W.M. Dunstan. 1971. Nitrogen, phosphorus, and eutrophica-
tion in the coastal marine environment. Science, Vol. 171: 1008-1013.
Schindler, D.W. 1977. Evolution of phosphorus limitation in lakes. Science,
Vol. 195: 260-262.
Schofield, C.C. 1976. Acid precipitation: Effects on Fish. Ambio 5(5-6):
228-230.
Schwartz, C.C., W. K. Lauenroth, and R.K. Heitschmidt. 1977. Effects of
controlled levels of sulfur dioxide on the nutrient quality of western
wheat grass and prairie June grass. In Press. Colorado State Univ.
46
-------
Smith, W.H., and L.S. Dochinger. 1976. Capability of metropolitan trees to
reduce atmospheric contaminants. In: Proceedings, Better Trees for
Metropolitan Landscapes, H. Gerhold, F. Santamor and S. Little, eds.,
U.S.D.A., Forest Service, Gen. Tech. Report, NE-23, Upper Darby, Pa.,
pp. 49-59.
SNSF Project. 1977. SNSF project ~ Condensed Program 1977-79. SNSF project,
Norwegian Forest Research Institute, Aas,Norway, 16 pp.
Stevens, R.K. Sampling and analysis of atmospheric sulfates and related
species, to be published in Atmospheric Environment, January, 1978.
Tamm, C.O., and E.B. Cowling. 1976. Acidic precipitation and forest vegeta-
tion, pp. 845-855. In Proc. First Intern. Symp. on Acid Precipitation
and the Forest Ecosystem. U.S.D.A. Forest Service, Gen. Tech. Rept.
NE-23. Upper Darby, Pa.
Tamm, C.O., G. Wiklander, and B. Popovic. 1976. Effects of applications of
sulfuric acid to poor pine forests, pp. 1012-1024. In: Proc. First
International Symposium on Acid Precipitation and the Forest Ecosystem.
L.S. Dochinger and T.A. Seliga, eds. USDA Forest Service Gen. Tech.
Rept. NE-23. Upper Darby, Pa.
Tamm, C.O. 1976. Acid precipitation: Biological effects in soil and on
forest vegetation. , Ambio 5: 235-238.
Taylor, O.C. 1969. Importance of peroxyacetyl nitrate (PAN) as a phytotoxic
air pollutant. J. Air Pollut. Control Assoc. 19: 347-351.
Taylor, O.C., and P.R. Miller. 1973. Modelling the oxidant air pollutant
impact on a forest ecosystem. Calif. Air Environment 4(1): 1-3.
Tesche, T.W., J.A. Ogren, and D.L. Blumenthal. 1977. Ozone concentrations
in power plant plumes: comparison of models and sampling data. Proc.
Int. Conf. Photochemical Oxidant Pollution and Its Control. I: 157-172.
Tingey, D.T., R.A. Reinert, J.A. Dunning, and W.W. Heck. 1971. Vegetation
injury from the interaction of nitrogen dioxide and sulfur dioxide.
Phytopathology 61: 1506-1511.
Treshow, M. 1970. Environment and Plant Response. McGraw-Hill Book Co.,
- N.Y., pp. 269-373.
Treshow, N. 1975. Interaction of air pollutants and plant disease, pp.
307-334. In: Responses of Plants to Air Pollution. J.B. Mudd and T.T.
Kozlowski, eds. Academic Press, NY. 383 pp.
Trijonis, J., and K. Yuan. Visibility in the southwest. TSC-PD-B562-1, Santa
Monica, Ca: Technology Service Corp., 1977.
47
-------
USDA, Forest Service. 1977. File report of 1974 to 1976 surveys for oxidant
injury in the Sequoia National Forest. Forest Pest Management, San
Francisco, Region 5.
USDA, Forest Service. 1973. Air pollution damages trees. Northeastern
Forest Exp. Sta., Upper Darby,Pa., 32 pp.
U.S. Senate, Committee on Public Works. 1975. Air quality and stationary
source emission control. Serial No. 94-4. Washington, D.C.
Van Haut, H., and H. Stratmann. 1970. Farbtafel atlas uber Schwefeldioxid
Wirkungen an Pflanzen. Verlag W. Girardet., Essen. 206 pp.
Van Hook, R.I., and W.D. Schults. 1977. Effects of trace contaminants from
coal combustion. Proc. Workshop Aug. 2-6, 1976, Knoxville, Tennessee.
Energy Research and Development Administration, Washington, D.C. ERDA
77-64, 79 pp.
Vaughan, B.E., K.H. Abel, D.A. Cataldo, J.M. Hales, C.E. Hand, L.A. Rancitelli,
R.C. Routon, R.E. Wildung, and E.G. Wolfe. 1975. Review of potential
impact on health and environmental quality from metals entering the
environment as a result of coal utilization. A Battelle Energy Program
Report. Battelle Memorial Institute, Richland, Washington, 75 pp.
Waddell; I.E. 1974. The Economic Damage of Air Pollution. EPA-600/5-74-
012. U.S. Environmental Protection Agency, Washington Environmental
Research Center.
Waggoner, A.P., and R.J. Charlson. Aerosol Characteristics and Visibility.
EPA-600/3-77-072. USEPA Research Triangle Park, NC, 11977.
Waggoner, A.P., A.J. Vanderpol, R.J. Charlson, S. Larsen, L. Granat, and C.
Tragardh. 1976. Sulfate-light scattering ratio as an index of the role
of sulfur in tropospheric optics. Nature 261: 120-122.
Weber, D.E. 1977. The effects of ozone on plant parasitic nematodes and
certain plant microorganism interactions. Proc. Int. Conf. Photochemical
Oxidant Pollution and Its Control. USEPA. Ecological Research Series
EPA-600/3-77-001B. pp. 621-631.
Weinstein, L.H., D.C. McCune, A.L. Aluisis, and P. Van Lenken. 1975. The
effect of sulphur dioxide on the incidence and severity of bean rust and
early blight of tomato. Environ. Pollut. 9: 145-155.
Weiss, R.E. 1977. Sulfate Aerosol: Its geographical extent in the midwest-
ern and southern United States. Science: 195, pp. 979-981.
Wert, S.L., K.A. Zealear, and R.C. Heller. 1971. Air pollution impact on
the Angeles National Forest. File Report, 4600 Series USDA, Forest
Service, PSW, Berkeley, CA, 1971.
48
-------
Westman, W.E. 1977. How much are natures services worth? Science 197: 960-
964.
White, W.H., D.L. Blumenthal, J.A. Anderson, R.B. Husar, and W. E. Wilson, Jr.
1977. Ozone formation in the St. Louis plume, Internat. Conf. on photo-
chemical Ox. Pollut. and Control, Proceed. I: 237-248.
Williams, W.T., M. Brady, and S.C. Willison. 1977. Air pollution damage to
the forests of the Sierra Nevada Mountains of California. J. Air Pollut.
Control Assoc. 27: 230-234.
Wilson, W.E. 1977. Sulfates in the Atmosphere, EPA 600/7-77-021, USEPA
Research Triangle Park, NC.
Wodzinski, R.S., D.P. Labeda, and M. Alexander. 1977. Toxicity of S02 and
NO : selective inhibition of blue-green algae by bisulfite and nitrite.
J.xAir Poll. Control Assoc. 27: 891-893.
Woodwell, G.M. 1970. Effects of pollution on the structure and physiology
of ecosystems. Science 168:429-433.
Wright, R.F., and E.T. Gjessing. 1976. Acid precipitation: changes in the
chemical composition of lakes. Ambio 5(5-6): 219-223.
Yamamoto, K. 1975. The relationship Between Relative Humidity and Mass of
Deliquescent Aerosols. Master's Thesis, Washington University, St.
Louis.
49
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1 REPORT NO
EPA-600/7-78-108
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Environmental Effects of Increased Coal Utilization:
Ecological Effects of Gaseous Emissions from Coal
5. REPORT DATE
June 1978
6. PERFORMING ORGANIZATION CODE
7. A
8. PERFORMING ORGANIZATION REPORT NO.
Norman R. Glass, Editor
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Corvallis Environmental Research Laboratory
200 SW 35th Street, Corvallis, OR 97330
10. PROGRAM ELEMENT NO.
1NE625
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
Office of Health and Ecological Effects
Office of Research and Development
Environmental Protection Agency
Washington, DC 20460
13. TYPE OF REPORT AND PERIOD COVERED
final
14. SPONSORING AGENCY CODE
EPA/600/02
15. SUPPLEMENTARY NOTES
The attached report is part of an interagency committee report prepared at the re-
quest of the DOE in response to the President's Environmental Message.
BSTRACT
s report is provided for the "Health and Environmental Effects of Coal Utilization"
Committee (Dr. David Rail, Chairman) which was created by the request of the DOE in
response to the President's Environmental Message. It evaluates ecological and environ
mental effects of gaseous emissions and aerosols of various types which result from coa
combustion. The report deals with NOX, SOX. fine particulate, photochemical oxidant
and acid precipitation as these pollutants affect natural and managed resources and
ecosystems.
The economic implications of ecological effects are identified within acceptable limi
In addition, the reliability of the data base upon which conclusions or estimates are
made is evaluated to the degree possible. Aquatic and terrestrial effects are dis-
tinguished where the pollutants in question are clearly problems in both media.
Sulfur oxide (SOX) emissions and nitrogen oxide (NO ) emissions are projected to be
higher in 1985 and 2000 than in 1975. Since SOX and NOX are major contributors to acid
precipitation, substantial increases in total acid deposition can be expected in the
nation as a whole. At present, acid precipitation is most abundant in the North Central
and Northeastern States.
Estimates of the non health-related cost of air pollutants range from several hundred
million dollars per year to $1.7 billion dollars per year. In general, these estimates
include only those relatively easily measured considerations such as crop losses result-
frnm amt-p pollution episodes or cost of frequent repainting a<; a rpsult- nf air --•"••• *---
17. KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
COSATI Field/Group
coal use-environmental effects
acid precipitation
04/B
06/F
18. DISTRIBUTION STATEMENT
release unlimited
19. SECURITY CLASS (This Report)
non-classified
21. NO. OF PAGES
60
20. SECURITY CLASS (Thispage)
non-classified
22. PRICE
EPA Form 2220-1 (R«v. 4-77) PREVIOUS EDITION is OBSOLETE
50
ft U S. GOVERNMENT POINTING OFFICE: 1970-797.307/196 REGION 10
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