7-
v>EPA
o. /
United States
Environmental Protection
Agency
Office of Policy Analysis
Office of Policy, Planning
and Evaluation
February, 1987
Unfinished Business:
A Comparative Assessment
of Environmental Problems
Appendix III
Ecological Risk
Work Group
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COMPARATIVE ECOLOGICAL RISK
A REPORT OF THE ECOLOGICAL
RISK WORKGROUP
FEBRUARY 1987
0.S. Environmental Protection Agency
^ffiS
Chicago, IL 60604-3590
U.S. ENVIRONMENTAL PROTECTION AGENCY
Washington, D.C. 20460
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ACKNOWLEDGEMENT
The followinq members of the Ecoloaical Risk Workgroup,
representing various organizational components of EPA, were
the principal contributors to the development of this report,
Rebecca Hanmer (Chairperson)
Dennis Athayde
Robert Bastian
*Jay Benforado
*Peter Caulkins
Wendy Blake-Coleman
*David Davis
Robert Davis
Greene Jones
Charles Delos
James Gilford
*Charles Gregg
Norbert Jaworski
Debora Martin
Brian McLean
Gregory Peck
James Plafkin
*Michael Slimak
James Weigold
Robert Zeller
*Writers and Editors
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TABLE OF CONTENTS
INTRODUCTION
PART I RANKING OF PROBLEMS; CONCLUSIONS AND
RECOMMENDATIONS
PART II APPROACH AND METHODS
DEVELOPMENT OF A RANKING METHODOLOGY
APPLICATION OF THE RANKING METHODOLOGY
PART III OBSERVATIONS AND COMMENTS
THE ENVIRONMENTAL CONTEXT
THE INSTITUTIONAL CONTEXT
METHODOLOGICAL PROBLEMS
PART IV APPENDICES
- REPORT OF THE EXPERT PANEL CONVENED BY
THE CORNELL ECOSYSTEMS RESEARCH CENTER
- INDIVIDUAL PAPERS DESCRIBING THE PROBLEMS
ADDRESSED BY THE ECOLOGICAL RISK
WORKGROUP
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INTRODUCTION
The Comparative Risk Project was formally initiated in
May 1986, following several months of planning and organizational
activity. Its objective was to estimate and rank current
environmental risk under existing levels of control for the
purpose of assisting EPA in setting program and budget priorities.
Four subordinate workgroups were chartered to deal with cancer
risks, noncancer health risks, welfare effects and ecological
effects. Each workgroup was to address, evaluate, and to the
extent possible rank the risks presented by 31 environmental
problems which EPA has some responsibility and authority to
control. This report presents the efforts and conclusions of
the Ecological Risk Workgroup.
We believe that our task was guite different from the tasks
of the other workgroups. While not necessarily more difficult,
it was more complex in several respects. The risks we evalua-
ted are not risks to a single species, man, nor to interests
that can be valued in dollars. They are risks of damage to
entire ecological systems, to geographical regions, and to the
biosphere itself. Ecological systems are complicated entities
composed of multiple plant and animal populations and the associ-
ated physical environment, and contain a host of internal
relationships. The severity of risk to ecosystems due to chemi-
cal and physical stresses seldom can be measured just by the
weakening or destruction of a species, or even by the elimination
or weakening of an individual relationship; severity of risk is
measured by changes in the basic characteristics of the system as
a whole. In general, we evaluated these effects by estimating
interference with the normal structure and functioning of ecologi-
cal systems, and the period of time they typically reguire to
recover from environmental stress. Furthermore, there are many,
very different ecosystem types, and they respond differently to the
stresses we evaluated; some are relatively strong and stable in
reacting to the same stress agents that produce severe reactions in
other ecosystems.
We believe that readers will be helped by some brief back-
ground on ecosystems, and thus how damage to those systems may
occur. Ecosystems are complex combinations of plants and animals
interacting with each other and with their physical environment.
These systems manifest structural and functional patterns; they
obtain the energy and raw materials necessary for growth, mainte-
nance and reproduction from the physical environment, and from
living parts of the system. All living organisms absorb, transform
and circulate materials and energy through the ecosystem.
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In a broad sense, ecosystems can range in size from a drop of
water to the entire biosphere. Ecosystems are biologically and
physically different from one another with organisms specially
adapted to their particular environments. Regardless of size
of an ecosystem, all components of ecosystems operate as parts
of the whole ecosystem.
Theoretically, ecosystems and the internal interactions in
the ecosystem among plants, animals and the physical environment
tend to attain stability over time. Thus the structural and func-
tional properties of ecosystems should remain relatively unchanged
over long periods of time. Actually, ecosystems exhibit varying
degrees of natural fluctuation around an environmentally determined
eguilibrium point. Mechanisms for stability operate at many
levels within ecosystems to maintain this dynamic balance. It is
through these mechanisms that ecosystems derive their capacity to
accommodate anthropogenic as well as natural disturbances.
Ecosystems can nevertheless be delicate. Modify the particu-
lar mechanisms for stability that keep the system stable, and the
ecological balance changes. Interdependency in an ecosystem can
mean that the decline of one species can potentially affect the
entire system, though freguentiy one species can be substituted
for another in an ecosystem without seriously affecting the eco-
system as a whole. Disruptions to ecosystems have been compared
to the ripple effect that occurs when a stone has been thrown into
a pond. Much of ecology is an attempt to ascertain the conseguence
of each of these ripples.
Traditional toxicological approaches to assessing risk to
individual species are not very useful in evaluating the likely
response of ecosystems to anthropogenic disturbance. (Thev would
not even be relevant in evaluating physical alteration of habitat, as
distinct from chemical stress.) The results of tests on
individuals or single species freguentiy cannot be directly trans-
lated into effects on populations in natural communities, let alone
overall impacts on ecosystems, with their large numbers of living
and non-living components and networks of interrelationships. What
is needed to assess ecological risks is evidence as to how whole
natural systems react to stresses. Such system-level studies are
freguentiy not available. It is within this context that we
have done our best to assess risk to ecological systems.
In this report, we have used the term "risk assessment" to
denote the process we employed in ranking the problems or to
characterize the methods used to estimate ecological effects. We
have used this language because it is the common currency of the
larger Comparative Risk Project, and it serves as a convenient
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shorthand descriptor. It is critical, however, for the reader to
keep in mind that the phrase has a different operational meaning
in our context. Specifically, it should not be confused with
common useage in evaluating human health response to toxic substan-
ces, where risk assessment has come to be widely perceived as a
highly quantitative, sophisticated, analytic process. Risks are
often expressed as the probability of occurrence for an event of
interest, such as contracting cancer within a lifetime. In the
context of our efforts, the term has a meaning much closer to that
of the term "environmental impact assessment", which often involves
assessments of exposure potentials and effects, and may involve
predictions, but only rarely is quantitative and almost never
probabilistic.
Nor does the workgroup claim to have conducted this assess-
ment as a traditional scientific analysis with its attendant data
quality, reproduceability, documentation, and other requirements.
Rather, the assessment was conducted as a consensus building process
relying on available data and group debate, and involving much
individual judgment. This is not to imply, however, that the
process lacked objectivity or rigor — both of which are attainable
in a consensual process. In light of data limitations, one conse-
quence of this approach is that visibility of a particular problem
or issue carries a great deal of weight, and visible issues may
tend to "float to the top" while less visible matters may remain
unaddressed. However, we believe that a more "scientific" analy-
sis would not be likely to change the results of our ranking
substantially (given the same set and definition of problems). If
the results were to change, it would probably be at the margin or
among the lower ranked problems.
As noted, the workgroup experienced difficulty in acquiring
data. This resulted partly from the difficulty of bringing data
together in the time available, and partly from the fact that ade-
quate data do not exist for many of the problem areas.
We believe, as indicated above, that the evaluations are
substantially sound. This was largely due to the recurring, intense
effort of many of the members of the workgroup in many meetings. The
workgroup was fortunate in having many members with substantive
background and training in ecology to back up broad experience and
personal knowledge about pollutant releases and ecological responses
across the Agency's programs. We also acknowledge with gratitude
the great assistance we received from the expert panel described
later in this report. Thus, while we expect that better data and
more refined method can lead to more confidence, we believe that the
conclusions presented here can be usefully applied in determining
agency priorities.
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Organization of Report
The primary responsibility of the work group was to rank
specified environmental problems according to ecological risk;
the results are summarized in Part I. Also contained in Part I
are certain general conclusions the workgroup reached on ecological
risks and how EPA addresses them, together with related recommenda-
tions.
Part II of the report describes in more detail the workgroup's
approach and methods used to develop the rankings. Part II also
desribes the assistance provided us by the expert panel of scien-
tists convened by the Cornell Ecosystems Research Center.
Part III includes comments and observations on ecological
risk and its priority in EPA, and describes in more detail the
difficulties in ranking ecological risks.
Part IV is an appendix containing the full report of the panel
of experts convened by the Cornell Ecosystems Research Center, and
the papers on individual problems which we used in developing the
rankings.
The members of the workgroup encourage a careful reading of all
parts of this report.
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PART I
RANKING OF PROBLEMS; CONCLUSIONS AND RECOMMENDATIONS
Over the course of several months, the workgroup conduc-
ted several successive rankings of the environmental problems,
and contemporaneously developed and refined its methodology
for evaluating them — the latter with the notable contribu-
tion of the expert panel convened by the Cornell Ecosystems
Research Center. Part I contains a brief description of
the methodology and its development; our rankings and the
basis for ranking position; and our conclusions and recommen-
dations on several issues and concerns that arose in the
course of our conduct of the ranking exercise.
RANKING OF PROBLEMS
Approach and Methodology
Here is how the workgroup approached its task of ranking
the relative ecological risk of a set of environmental
problems.
0 We modified the initial list of environmental problems
by dropping five which presented little or no ecological
risk (e.g., indoor air pollution); by combining others where
we felt it more useful for assessing ecological risk; and by
redefining others to account better for ecological risk.
We ended up with 22 problems. Our modification of the list
is detailed in Part II, and the modified list is Table 3.
We note that the original list (as well as our modified
list) both include disparate and overlapping environmental
problems of different magnitudes; this tends to bias the
rankings.
0 For purposes of evaluating ecological risk, in our
first ranking we developed nineteen categories of ecosystems
and other objects of ecological concern. Subseguently,
following the workshop held by the expert panel, we decided
to use the panel's reasonably similar breakout into sixteen
ecosystems of concern (four freshwater, three marine and
estuarine, four wetland and five terrestrial). (See Part
II)
0 The expert panel, in evaluating potential risk to
ecosystems, broke out the types of stresses associated
with the problems into 26 airborne, waterborne, and other
"stress agents" (e.g., waterborne toxic organics, gaseous
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phytotoxicants, radionuclides). We decided this was a
valuable perspective and used these stress agent categories
in our approach to ranking problems. (see Part II)
0 The panel also characterized these stress agents as
to scale of potential impact — whether the stress agent's
impacts would be limited to local ecosystems, or would affect
broader geographical regions or the entire biosphere. We
too applied this scalar concept in our ranking. We did not
attempt to agree on a precise definition of "regional" and
"local" (i.e., we did not use a 50-mile radius or other
specific measure of scale as defining the boundary between local
and regional).
0 To evaluate and rank ecological impacts deriving from
each of the 22 environmental problem areas (as distinct from
potential impact from a particular stress agent, which may
result from several problem areas), we needed problem-related
information concerning sources and emissions, and especially
concerning exposures (including geographical extent, location,
intensity, freguency and the like). For this purpose, problem
papers were prepared for each of the twenty-two problems
(See Part IV). We used the information and judgments in
these papers, as well as the collective knowledge of the
workgroup. As noted elsewhere, our information was weak in
many problem areas.
0 To assess the risk to ecosystems, the workgroup
considered basic changes in the structure of the ecosystems
and in their functions as indicators of serious impact. The
workgroup also took into account the reversibility of the
impact, and the time it would take the ecosystem to recover
when the stresses were removed. For many reasons, we conclu-
ded we could not use a prescriptive or quantitative approach
in taking these factors into account.
0 We gave some effort to whether it would be possible
and useful to rank ecosystems according to their inherent
vulnerability to damage from environmental stresses. We
concluded generally that this was not a good approach. Many
(perhaps most) ecosystems react differently to different
kinds of stresses. Wetlands, for instance, because of their
natural assimilative capacity, appear to be relatively less
vulnerable to chemical pollution than lakes or streams;
however, they are extremely vulnerable to physical altera-
tion or destruction.
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0 In sum, then, the workgroup evaluated and tried to
rank the ecological risk posed by 22 environmental problems
by estimating the impact of the problems on many different
kinds of ecosystems as well as on broader geographical regions
and on the biosphere. The impacts estimated are those that
occur under current conditions of control as a result of
exposure to the stress agents produced by the problem sources.
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RANKING RESULTS
Table 1 summarizes the rankinq of 19 environmental problems
in terms of ecological risks. These rankings represent a
consensus (if not unanimity in every case) of the workgroup.
We assigned the problems to six rank groups, with ecological
risk judged to be highest in rank group one, descending to
least in rank group six. Problems are not ranked within the
rank groups. Three problems were not ranked for lack of
reasonable certainty.
Table 2 arrays the ranking results in a matrix according
to geographic scale of impact — local, regional, and
biospheric. As shown in this matrix, environmental stresses
occurring at larger scales tend to be of greater concern. This
is true for both ecological and control reasons. Mitigation
or amelioration of large-scale ecological impacts is usually
difficult. Even low-level impacts that affect large areas
can be difficult to detect and trace back to a cause, thus
substantially increasing the time before applying controls.
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Table 1
Summary Ranking of Ecological Risks
Rank Environmental
Problem
Rationale for Ranking Position^
Stratospheric ozone
depletion (7)
C02
warming (8)
Intensity of impact; High (can
severely damage all natural systems,
particularly primary productivity).
Scale of impact; Biospheric
Ecosystem recovery; Recovery period
extremely long; impacts may be
irreversible.
Control; Effective controls require
coordinated, international effort
that will be very difficult to
obtain.
Uncertainty; Effects of ozone
depletion uncertain; ecological
response to global warming is well
characterized. Rate and timing
of the problem is uncertain.
Physical alteration
of aguatic habitats
(13/14)
Mining, gas, oil
extraction and
processina wastes
(20)
Physical risks from problems #13/14
and #20 are similar, except #20 in-
cludes terrestrial impacts.
| Intensity of impact; High (can
both degrade and completely
destroy ecosystem structure and
functions). Mining poses severe
impacts on water ecosystems.
Scale of impact; Local to regional.
Ecosystem recovery; Physical impacts
are generally irreversible.
Control; Low degree of controll-
ability.
Uncertainty; High degree of cer-
tainty associated with effects.
Criteria air
pollutants (1)
Point-source
discharges (9/10)
Nonpoi nt-source
discharges and
in-place toxics in
sediment (11)
Pesticides (25/27)
While problems #1, #9/10, 11, and
#25-27 do not share common charac-
teristics, they are rank-grouped to-
gether.
Intensity of impact; High (tend to
directly affect ecosystem functions
and indirectly affect ecosystem
structure).
Scale of impact; Local and regional.
Ecosystem recovery; Impacts are
generally reversible.
Control; Degree of control varies
among the problems in this rank
group; more controllable than rank
group #1.
Uncertainty; Some uncertainty, but
much is known about these effects.
1 Problems are presented in numerical order within each category
of rank; no ranking inference should be made within these categories.
The numbers in parentheses following the problems are those used in
the Comparative Risk Project listing.
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Table 1 (Cont.)
Summary Rankinq of Ecological Risks
Rank Environmental
Problem
Rationale for Rankinq Position^
Toxic air pollutants
(2)
Intensity of impact; Medium. Grow-
ing evidence to indicate that toxic
air pollutants responsible
for ecological damage.
Scale of impact; Local to regional .
Ecosystem recovery; Unknown,.
Control; Unknown, but likely to be
difficult
Uncertainty;
Substantial.
Contaminated sludge
(12)
Inactive hazardous
waste sites (17)
Municipal waste
sites (18)
Industrial non-
hazardous waste sites
(19)
Accidental Releases
of Toxics
(21)
Oil spills (22)
Other ground water
contamination
(24)
These problems overall have localized
releases and effects
Intensity of impacts; Medium (many
sources; impacts generally low, but
can be high locally).
Ecosystem recovery; Uncertain.
Control; Variable.
Uncertainty; Moderate
Radiation other
than radon (6)
Active hazardous
waste sites (16)
Underground Storage
tanks (23)
These problems are characterized
by few large releases, a high
degree of control for #6 and #16.
Intensity of Impacts; usually low
though could be moderate to severe
locally in unusual circumstances.
Scale of Impact; local
Ecosystem recovery; uncertain
Uncertainty; moderate
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Table 2
Scale of Ecological Risks
BIOSPHERE
REGIONAL
LOCAL
HIGH
MEDIUM
LOW
Stratospheric ozone
depletion (7)
CO2 and global
warminq (8)
Criteria air pollutants (1)
Point-source discharges (9/10)
Nonpoint-source discharges (11)
Physical alteration of aquatic
habitats (13/14), Mining (20),
Pesticides (25-27)
| Toxic air pollutants (2/3)
Contaminated sludge (12)
Inactive hazardous waste
sites (17)
Municipal waste sites
(18)
Industrial waste sites
(19)
Accidental release of
toxics (21)
Oil spills
(22)
Other ground water
contamination
(24)
Radiation (6)
Active hazardous waste
sites (16)
Underground storage
tanks (23)
See footnote to Table 1
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BASIS FOR RANKING POSITION
Summarized below are the primary reasons for the ranking
of environmental problems shown on Tables 1 and 2. The
background papers on individual environmental problems in
Part IV should be consulted for information used by the workgroup
in deriving the rankings. The numbers in parentheses refer to
the problem numbers originally assigned by the Comparative
Risk Project.
Stratospheric Ozone Depletion (7)
This problem affects all ecosystems, many in a profound way.
Because the ozone layer shields the earth's surface from
damaging ultraviolet radiation, ozone depletion could reduce
basic ecological processes such as primary productivity. The
effect would likely be extreme in many ecosystems (e.g.,
destruction of the phytoplankton that exist in the surface
layer of the oceans). The severity of the potential ecological
impacts that could result from increased UV radiation, the
global scale of many of the impacts, and their irreversibility
more than offset major scientific uncertainties, and result in
ranking in the highest risk group.
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CO? and Global Warming (8)
As with stratospheric ozone depletion, this problem has
a very hiqh impact on ecosystems. Industrial-related air
emissions, combustion of fossil fuels, deforestation and
other releases of CC>2 may cause qlobal temperatures to
increase 1.5° - 4.5° C over the next 50-75 years. Such a
rapid change would be unprecedented. World-wide global.
warming would raise the sea level, significantly alter the
hydrological cycle and have a major impact on coastal estuaries
and tidal wetlands. Global warming is also likely to alter
significantly the composition of biomass, especially biomass
produced in terrestrial systems. The global extent and
irreversible nature of climate alteration, as well as the
ecological conseguences and difficulty of control, result in
ranking in the highest risk group.
Physical Alteration of Aguatic habitats (13/14)
Physical impacts on aguatic systems result from a
diversity of human activities such as dredging and filling,
channelization, drainage, impoundments, mining, shoreline
stabilization, and silvicultural and agricultural activities.
These physical insults affect marine, estuarine and freshwater
systems by causing direct loss or alteration of habitat,
adding suspended matter to the water column, modifying
hydrology, and changing ambient water parameters. The threat
to wetlands as well as other aguatic systems is very high,
and is both local and regional in nature. (Note that physical
alterations to terrestrial ecosystems are not included in
this problem assessment.)
Mining (20)
The ecological impacts of resource extraction are felt
in all major ecological groupings. In addition to physical
alteration, the dominant stress agents are: acid mine drainage,
toxic inorganics, nutrients, turbidity, oils, solids and
groundwater contamination. Acid mine drainage and toxic
inorganics, which substantially impact freshwater and terres-
trial systems, are of only moderate importance in wetlands
and estuaries. Nutrients have high impacts in freshwater
systems, moderate to low impact in other systems. Habitat
alteration is serious in several types of ecosystems. The
risk from mining may be local to regional in scale, and the
overall problem is ranked high.
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Criteria Air Pollutants (1)
The most prominent stress elements of this problem are acid
deposition and ozone (in the troposphere, not the stratosphere).
The impacts of ozone on forests and natural ecosystems are
long lastinq. Acid deposition affects ecosystems where the
buffering capacity of soil and water is low, especially in
areas of the upper Midwest, the Northeast, Southeast and some
areas in the Western mountains. Because of the very high
level of emissions, the regional extent of potential impacts,
the degree of effectiveness of current controls and the signi-
ficance of observed effects, this problem ranked high.
Point-Source Discharges (9/10)
Over 65,000 facilities discharge pollutants directly into
the Nation's surface waters. Of these, about 39,000 are impor-
tant sources of both conventional (e.g., solids and biochemical
oxygen demand) and toxic pollutants. Most point sources are
located in the more heavily populated and industrialized regions
of the U.S. Virtually all of the water-borne stress agents
identified by the expert panel emanate in point source dischar-
ges. They discharge more toxics than sources in any other
problem and are major contributors to loadings of BOD, solids,
nutrients and chlorine. These releases have resulted in a
deterioration of water guality which seriously affects aguatic
ecosystems. Over 40% of the assessed stream miles in the U.S.
with documented impairments are impacted by point sources, as
are half of the impacted estuaries and coastal waters. This
problem ranks high because of extent, seriousness and scale of
impact.
Nonpoint-Source Discharges (and Sediment bound Toxics) (11)
Nonpoint-source pollution results from activities on
the terrestrial environment. Rainfall runoff carries pollution
into surface waters. Major sources are agriculture (sediment
and chemicals), silviculture (sediment), construction (sediment),
urban environments (sediment and chemicals), resource extrac-
tion (sediment) and hydrologic modification. The problem is
widespread. Over 50% of the nation's lakes that have been
assessed and almost 40% of the assessed river miles are impacted
by nonpoint-source pollution. This problem ranks high by
reason of the extent, scale and significance of its damage to
aguatic ecosystems and current inadeguate control.
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Pesticides (25-27)
About 3.5 billion pounds of formulated pesticide products
are used each year —79% by agriculture, 15% by industry and
6% by households. Pesticides are designed to kill living
organisms, and unintended exposure to them can be very destruc-
tive. Most agricultural production is treated with pesticides.
Crops treated with pesticides are grown in the vicinity of
most kinds of ecosystems. Aguatic ecosystems receive pesti-
cides directly and through agricultural runoff. Freshwater
systems ultimately lead to coastal and estuarine systems,
which also receive pesticides directly. Fish and wildlife
are exposed to pesticides through inhalation, ingestion, and
dermal absorption. Residues on food — plants, seeds, insects
and water—in their habitat result in direct exposure.
Certain pesticides bioaccumulate and contaminate food chains.
Extent of the problem, severe impact on ecosystems and level
of current control contribute to a high ranking.
Toxic Air Pollutants (2)
Sources of toxic air pollutants are widely varied and
include traditional air pollutant sources such as emissions
from chemical plants, motor vehicles and metallurgical
processes, as well as non-traditional sources such as sewage
treatment plants. Sources of ecosystem exposure to toxic air
pollutants range from industrial emissions to the more routine
release of chemicals into the atmosphere as part of the
normal operation of countless human activities. Atmospheric
loading of toxic pollutants to the Great lakes appears to be
a major pathway, but the details are not well understood.
Since most of the data available on toxic air pollutants were
collected regarding human health concerns, the effect of
toxic air pollutants on ecosystems is not well characterized.
Contaminated Sludge (12)
The disposal of contaminated sludge is unlikely to result
in extensive damage to natural ecosystems where current and
expected control programs are properly implemented. However,
since contaminated sludges are clearly a potentially significant
source of BOD, solids, nutrients, toxic inorganics and
organics, and pathoaens, if the EPA permitting and enforcement
efforts that are currently in place and expected in the future
are not carried out, significant local ecological risks are
likely to occur.
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Inactive Hazardous Waste Sites (17)
A variety of contaminants at abandoned or inactive waste
sites can have localized effects on ecosystems. Information
from one survey shows ecosystem injury at 270 sites. Another
estimate is that about 6% of sites are likely to cause signi-
ficant natural resource impacts, including damage to surface
waters, wetlands, fisheries, and other impacts. It is diffi-
cult, however, to characterize potential ecological effects
at superfund sites because of lack of data.
Municipal Nonhazardous Waste Sites (18) and
Industrial Nonhazardous Waste Sites (19)
These two problems are summarized together, although
the types of sources are somewhat different. Chemicals from
these waste sites may contribute directly and indirectly to
the degradation of surrounding ecosystems primarily via
surface water runoff and air volatilization routes. They
can enter surface waters indirectly via ground water. While
these waste sites exert only local impacts on ecosystems,
their sheer numbers (over 16,000 municipal landfills and
almost 200,000 industrial disposal sites) produced the medium
ranking.
Accidental Release of Toxic Chemicals and Oil Spills (21 and 22)
These two similar problems are both rated medium., Oil
spills are freguent and can have spectacular conseguences if
the discharge is of sufficient magnitude, but typically
spills are small and occur in areas where there is sufficient
dilution to result in only a short-term impact. Toxic chemical
releases, such as railroad tank cars overturning and spilling
into streams, are perhaps more freguent, but the guantities
of these spills are typically less than from oil spills.
Chemical spills especially ift small streams can cause signifi-
cant effects on stream ecosystems, but these are usually of
short duration.
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Other Sources of Ground Water Contamination (24)
The overall potential for ecological risk is substantial
because of the large number of sources and the lack of
controls for many of them. This threat is diminished because
ecological impacts occur only when groundwater contaminated
by the various sources is discharged from aguifers in suffi-
cient volume and concentration to affect the receiving aguatic
or wetland ecosystems. Additionally, the filtering properties
of soils and the dilution and dispersion processes of streams
and other aguatic systems reduces ecological risk. The
large number of sources, plus the lack of control for many
sources, resulted in a medium ranking.
Radiation Other Than Radon (6)
Active Hazardous Waste Sites (16)
Underground Storage Tanks (23)
These problems were ranked low for a number of reasons.
Active hazardous waste sites are probably adeguately control-
ling releases so as to protect natural ecosystems. Anthropo-
genic radiation is localized or adeguately controlled, effects
on ecosystems are rare, and the likelihood of a catastrophic
event that would cause serious ecological damage is consi-
dered to be low. Underground storage tanks contain hazardous
chemicals as well as petroleum products, and there are
thousands around, but the release of contamination through
groundwater, largely in urbanized environments, means rela-
tively low and localized impacts on ecosystems.
New Toxic Chemicals (28)
Biotechnology (29)
Discarded Plastics (30)
Because of uncertainty, the workgroup did not rank new
toxic chemicals, biotechnology, and discarded plastics in
the marine environment.
Biotechnology is a new technology. Products of recombi-
nent DNA that EPA has evaluated thus far present very little
risk to ecosystems. However, biotechnology could signifi-
cantly harm ecological systems if bioengineered organisms
that would have a competitive advantage in the environment
were inadeguately controlled and released to the environment.
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The ecoloqical risk of new toxic chemicals also cannot
be ranked because the extent of current control is not known.
If EPA's process for preinanufacture review of new chemicals
is working, they should have only a small ecological impact,
since the chemicals would be regulated before manufacturing.
The potential for environmental releases and damage cannot,
however, be determined with any great certainty from the
information contained in premanufacture submissions. Once
EPA lists a chemical, manufacturers can produce it in any
guantities, and for different uses, unless EPA promulgates
a "significant new use" rule. In general, new toxic chemicals
can have the same potential for widespread release as similiar
existing industrial chemicals.
The problem of discarded plastics - and in particular,
plastics in the marine nevironment - is believed to be
significant in terms of wildlife killed (e.g., fish and
dolphins), but our information on the extent of effects on
populations and on marine ecosystems is insufficient to rank
this problem.
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CONCLUSIONS AND RECOMMENDATIONS
During the course of its evaluation of ecological risk and
ranking of problems, the workgroup developed a number of percep-
tions about the nature and significance of certain ecological
problems, the extent of the Agency's emphasis on those problems,
and its capacity to deal with them. (See Part III for extensive
discussion of these matters.) In the following section the work-
group offers some conclusions and recommendations that go beyond
the direct charge to rank environmental problems.
Two predominant conclusions emerged:
Physical habitat alteration is the stress that has the
greatest adverse impact on ecosystems; and
EPA's capability to address ecological impacts
is inadeguate to support effective action to protect the
natural environment.
Habitat Alteration
Physical alteration of aguatic habitats was ranked in the
second highest risk group, and alteration or destruction of habi-
tat was a major basis for ranking global warming and mining high.
Many activities for which EPA does not have responsibility produce
extensive habitat alterations and loss. The workgroup believes
that physical alteration or destruction of natural communities —
both aguatic and terrestrial — is the most significant threat
to overall environmental guality that we face now and in the
future. While much of the popular coverage of this problem has
focussed on other parts of the world (for example, tropical
deforestation), the problem is no less significant for the United
States. Both the causes and the costs of significant habitat
alteration are many and pervasive. Among the more imnortant and
visible effects are biotic impoverishment, loss of resource and
economic values, loss of recreational potential, and the loss or
alteration of major components of biogeochemical cycles and proces-
ses, ranging from loss of assimilative capacity of aguatic systems
in ameliorating pollution to major changes in the global carbon
cycle and attendant changes in atmospheric processes. Although
EPA's authorities and tools are limited in this area, we can do
more than we are now doing.
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Accordingly, we recommend that the Agency conduct a compre-
hensive assessment of our authorities, activities, and capabilities
in the area of habitat protection. Where we already have signifi-
cant authorities and activities, we should determine whether to
enhance our efforts by the addition of resources, program or proce-
dural changes, increased research, greater work with other resource
management agencies or other means. Examples of areas of current
activity include water guality standards (particularly the anti-
degradation provisions), construction of sewage treatment plants,
regulation of mining and other mineral or fossil fuel extraction,
siting of solid/hazardous waste site management facilities, EPA
compliance with the National Environmental Policy Act and related
statutes/directives (e.g., Floodplain Management Executive
Order and Endangered Species Act), and EPA's responsibilities
for reviewing the actions of other agencies under section 309 of
the Clean Air Act. Where our authorities are less, we should
raise attention to habitat protection in our ongoing program
planning and decision-making, and consider steps to foster habitat
protection. We also recommend that EPA undertake a comprehensive
study, in cooperation with other agencies with responsibilities
for protecting ecological values, to describe their authorities
and programs for protecting ecological systems and the natural
environment from environmental stresses, with special attention
to the protection of habitat from alteration or destruction.
This study should look at both U.S. and global sources of ecological
stresses and locations of ecological systems impacted. It should
direct attention to those programs where EPA could assist other
agencies in carrying out their responsibilities. The product of
this study could help EPA to decide whether to expand or redirect
its own programs to address particular problems, or to work in
support of other agencies' programs dealing with them.
EPA's Ecological Capabilities
Many difficult methodological problems were encountered by
the workgroup in evaluating ecological risk over the course
of this project. EPA does not, in fact, have any generally accep-
ted methodology for assessing ecological risk. The workgroup
believes that the unavailability of methods to assess ecological
risk and the overall weakness of the data base for evaluation are
a reflection of inadeguate attention to ecological problems throug-
hout the Agency as well as of the inherent difficulty of evaluating
ecological risks.
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We recommend that the Agency, as soon as possible, develop and
issue interim guidelines for evaluating ecological risk for use by
program and regional offices. The experience of the workgroup,
together with currently available material developed by ORD, the
program offices, and organizations outside EPA, provide a good
foundation for describing one or more practical methods for use in
evaluating ecological risk. Such methods can serve until such
time (probably several years off) that elegant, "final" methodolo-
gies can be prepared, reviewed and published. This recommendation
does not aim at production of guantitative "risk assessment guide-
lines", as that term is perceived in EPA in connection with human
health risk assessment, but at methods of reasonable intellectual
rigor that will predict or estimate impacts gualitatively. We
believe that interim guidelines for evaluating ecological risk
could be prepared and issued in twelve months. The interim guide-
lines should be accompanied by a reference compendium of existing
methods, models, guidance, etc. for immediate, supplementary use.
We recommend that a strong effort be made to expand and
strengthen collection of data relating to the assessment of ecolo-
gical risk. Monitoring activities should focus on acguiring
more and better data on the intensity, geographical distribution
and location, and time periods of exposures to ecological stress
agents, and data indicating the response (bioeffects) of ecological
communities to those stresses. These individual program efforts
should be coordinated not only within EPA, but across other
Federal Agencies.
We recommend that a number of activities to support individuals
and programs engaged in ecological risk assessment be initiated or
strengthened;
(1) EPA should assemble and distribute standardized
descriptive information on environmental communities
and ecosystems in the U.S., including their vulnerability
to various environmental stresses. (Example: Aguatic
ecoregion atlases under preparation at the Corvallis
Laboratory). This should be accompanied by a desk
handbook of general information on ecosystems, reference
to more detailed sources, etc.
(2) The EPA headguarters Library collection on ecology and
natural history is deficient (particularly in comparison
with human health and engineering materials), and should
be upgraded (for instance, to include free government
publications such as the community/estuarine profile
series of the United States Fish and Wildlife Service).
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(3) Opportunities for basic training in ecology for EPA
employees trained in other professional or scientific
disciplines should be developed and made available,
perhaps through brief courses under the EPA Institute.
(4) Ways to facilitate better communication among EPA staff
with responsibilities for ecological risk assessment and
senior management should be improved so that professional
information and current experience can be exchanged and
made available to a wider audience. One method would be
a seminar series; a second would be a low budget newsletter.
We recommend that EPA review and amplify its current research
and development program for assessing ecological risk. A deeper
understanding of ecological systems and how stresses impact them,
as well as better technigues for evaluating ecological risk, are
needed. Our needs include:
Indicators of ecological stress;
Models for predicting or evaluating
ecological response to stress;
Methods for assessing the relative importance
of various stresses and impacts; and
Methods for monitoring the health and response
of ecological systems and communities.
In carrying out this effort, EPA should both employ its existing
research laboratories, and expand support for organizations such
as the Cornell Ecosystems Research Center.
We recommend that the Risk Assessment Council initiate, and
devote an increasing amount of its effort to, the planning,
sponsorship and review of activities relating to the evaluation
of ecological risk. The Risk Assessment Council should assume
the same responsibility for assuring the availability of guide-
lines for evaluating ecological risk as it does for guidelines
for evaluating human health risk. The membership and staff of
the Risk Assessment Council should be adjusted as necessary
to reflect this balance.
We recommend that across its full range of programs EPA give
substantially greater attention to ecological risks and their
control in its planning, priority setting and decision-making
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activities. EPA is not currently using its authorities for
ecological protection to their fullest or best advantage.
Efforts by EPA to protect threatened ecosystems or restore
damaged ecosystems are often capable of producing observable,
even reasonable, results.
(1) Wherever there exists the appearance of significant
incongruity between evaluations of ecological risk
and agency programs that can address those risks, an
examination of programs should be made to determine
the reasons for the incongruity and to adjust priority
and program content appropriately.
(2) Revision and initiation of ecological protection
activities should focus particularly on those
situations where "marginal utility" appears to be the
greatest. In particular, EPA should target its resources
and controls toward those problems in which environmental
values are particularly significant and where the risks
that can be avoided represent serious damage or destruction,
We further recommend that EPA periodically conduct thorough, compre-
hensive evaluations of ecological risk, employing the latest evalua-
tion methodology and technigues. A recurring comprehensive focus
on ecological problems will expand our understanding of their
scope and significance. ORD should perform a stronger role, in
cooperation with the program offices.
Recommendations affecting specific problems
Stratospheric Ozone Depletion (7)
Global Warming (8)
The ecological risks of stratospheric ozone depletion and global
warming due to increasing releases of CC>2 and other compounds were
ranked highest because of their global scale, severe damage to all
ecosystems, and irreversibility — problems of a different kind and
vast scale, as compared to other problems we considered. Moreover,
they are the least amenable to remedy, given their complexity
and pervasiveness, and the difficulty of implementing controls.
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In liqht of the extremely critical nature of these problems,
it is imperative that EPA act quickly and decisively. Accordingly,
we recommend that, building on its current activity,
(1) EPA review, summarize and evaluate information currently
available and investigations underway within and outside
EPA concerning the impact of ultraviolet radiation
(UV-B) on natural ecosystems (giving special attention
to UV-B impacts on the productivity of marine and freshwater
systems); determine what further investigations EPA should
sponsor to elucidate these impacts; and incorporate
statements concerning them in EPA's public communications
on the risk deriving from stratospheric ozone depletion;"
and
(2) The reports and research plans now being formulated for
global warming give appropriate coverage and priority to
ecological effects; that a comprehensive action strategy
provide for protection of ecological values; and guidance
be developed for the incorporation of global warming
effects in environmental impact assessment.
Pesticides (25/27)
The use of pesticides presents one of the greatest toxic
chemical threats to terrestrial ecosystems. The workgroup
supports continuing development of ecological risk assessment
tools; use of FIFRA to obtain data regarding the ecological risk
of pesticides; and reduction of risks to ecosystems by eliminating
or restricting those pesticides which pose an unacceptable risk
to ecosystems.
Discarded Plastics (30)
A considerable amount is known about kills of fish and other
organisms caused by non-degradable plastics (e.g., plastic netting
and plastic used to connect six-packs of beverages). Substitute
materials appear readily available. EPA should consider development
of a regulation under TSCA (and other available authority) to control
or prohibit use of non-degradable plastics in products that are used
or become waste in the marine environment.
Criteria Air Pollutants (1)
Regional concentrations of criteria pollutants such as sulfur
oxides and ozone adversely affect ecological systems. For example,
ozone causes a continuum of effects at various levels of organization
within plants from the cell to the ecosystem. These effects on plant
health and productivity ultimately have conseguences for an entire
-------
ecosystem. Ecosystem effects may be reflected in species (plant
and wildlife) diversification impacts, increased soil erosion,
or decreased capacity for watersheds. This potential chanqe in
the stability of ecosystems deserves more emphasis in research
that could support secondary standards.
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Part II
APPROACH AND METHODS
This part describes the approach used by the work
group in developing ecological risk rankings for a revised
list of environmental problems. The work group set out to
develop a pragmatic method to use for comparing the magnitude
of ecological risks. Members of the work group were chosen
either for their ecological background and training or for
their overall knowledge of the environmental problems within
EPA's program areas. Through an iterative process involving
many meetings, preparation of background papers, and assis-
tance from a group of academic scientists, the work aroup
evaluated the environmental problems from an ecological
perspective and formed a consensus on the significance of
ecological impacts for each problem area.
DEVELOPMENT OF A RANKING METHODOLOGY
Most approaches to risk assessment stress method and
procedure, in part because methods and procedures are viewed
as insurance against the limitations of human judgement. A
guantitative method-oriented approach works well within the
context of a well-defined model of a problem. Results derived
from the model are interpreted as conclusions about the
problem itself.
This approach does not work so well for ill-defined
and poorly understood problems for which generally accepted
models and adeauate data do not exist. The task of performing
a comparative ecological risk assessment across 31 broadly
defined "environmental problems" and a number of structurally
and functionally different ecosystems exemplifies a situation
where approaches relying less on detailed, guantitative
method must play a central role.
In these circumstances, the ecological risk workgroup conduc-
ted an initial assessment. This was fallowed by analyses and
refinement of our methodoloaical approach and preparation of
material to define the environmental problems. This resulted
in the approach and information used by the workgroup in its
ultimate ranking of problems.
Initial Assessment
Our initial task was to define a set of ecosystems on which
to focus the evaluation. While evaluating only a few ecosystem
categories would most likely result in missing important conse-
guences and distinctions, broadening the ecosystem categories
too far would make the assessment unwieldy, and complicated by
lack of data. The work group decided initially upon the following
categories of ecosystems:
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1. Marine and estuarine systems
a. deep ocean
b. shallow coastal waters
c. estuaries
d. tidal wetlands
2. Freshwater systems
a. cold water streams
b. warm water streams
c. lakes
d. wetlands
3. Terrestrial systems
a. arctic and alpine tundra
b. boreal coniferous forests
c. eastern deciduous forests
d. grasslands
e. hot deserts
f. subalpine coniferous forest (excludes boreal)
q. broad-leaved evergreen and subtropical forests
h. other
- western riparian zones
barrier islands
coastal dune-scrub
4. Special ecological areas/factors
a. soil - structure and microbiota
b. highly vulnerable animals, such as top
predators, marine mammals, relict populations
(e.g., fishes of desert springs)
c. migratory birds
A second task was to review the list of 31 environmental
problems to screen out, redefine or combine them where it would be
likely to sharpen the results of our evaluation. The following
changes were made:
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^ Problems #4 (Radon - indoor air pollution only)/
#5 (Indoor air pollution other than radon),
115 (Drinking water at the tap), #26 (Pesticide risk
to applicators), and #31 (Worker exposure to chemicals)
were eliminated from consideration because by definition
they were limited to health effects or the indoor
environment.
o Problems #13 (To estuaries near coastal waters and
oceans from all sources) and #14 (To wetlands from
all sources) are ecosystem categories, rather than
sources of pollutants. Both are included in the
ecosystems to be considered by the workgroup. Problem
#13/14 was redefined as dredging, filling,
channelization, and other physical modification of
aquatic systems. (Note: As a result of this redefini-
tion and neglect to provide elsewhere, we did not
rank the ecological effects associated with ocean
dumping or ocean incineration.)
o Problem #20 (Mining wastes) was expanded so as to include
not only the disposal of mining wastes, but also any
ecological impacts stemming from extraction of
mineral resources and their beneficiation (including
oil and gas).
o Problem #11 (Nonpoint-source discharges to surface
water) was expanded to include in-place toxicants in
the sediment.
o Problem #30 (Consumer product exposure) was in our
evaluation limited to ecological effects of discarded
plastic materials in the marine environment.
o Problems #2 and #3 were combined, as were #9 and
#10, and #25 and #27.
As a result of these revisions, the number of environmental
problems we considered was reduced from 31 to 22. A complete
list of the modified problems addressed by the workgroup is
shown in Table 3.
Using these problems and the ecosystem categorization above,
the work group conducted a preliminary subjective assessment
of each problem on an ecosystem-by-ecosystem basis, ranking
the problems as high, medium or low. The general criteria
used for this ranking follow.
1. direct physical destruction or major alteration;
2. changes in community structure/function;
3. changes in species richness and diversity;
4. threats to/loss of rare or endangered species;
5. localized versus national scale of impacts.
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Table 3
Modified List of Environmental Problems
1. Criteria air pollutants from mobile and stationary sources
— includes acid precipitation
2/3. Hazardous/toxic air pollutants and other pollutants
such as fluorides and total reduced sulfur
6. Radiation - Other than radon
7. Substances suspected of depletinq stratospheric ozone
layer (e.q., chlorofluorocarbons)
8. CC>2 and global warming
9/10. Direct and indirect point-source discharges to surface
waters (e.g., from POTWs, industrial dischargers)
11. Monpoint-source discharges to surface water, plus in place
toxics in sediment
12. Contaminated sludge - includes municipal and scrubber sludges
13/14. Physical alteration of aguatic habitat
16. Active hazardous waste sites - includes hazardous waste
tanks
17. Inactive hazardous waste sites - Superfund
18. Municipal nonhazardous waste sites
19. Industrial nonhazardous waste sites
20. Mining wastes and extraction
21. Accidental releases of toxics - to all media
22. Accidental oil spills
23. Releases from underground storaae tanks - includes product
and petroleum tanks, above ground and underground
24. Other groundwater contamination - includes septic tanks,
road salt, injection wells, etc.
25/27. Pesticide residues on food eaten by humans or wildlife; and
other pesticide risks - includes leaching and runoff,
deposition from spraying
28. New toxic chemicals
29. Biotechnology
30. Consumer products - limited to plastic material
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The general purpose of this initial assessment was to
test the feasibility and practicality of the overall approach,
to determine if the ecosystem categories and criteria were
meaningful, and to gain insight into the ranking process in
order to determine how best to focus the group's efforts.
The results shown in Table 4 reflect judgments based on
information generated in the assessment process, as well as
information from individual experience. Readers will note
that considerable change took place between this initial
assessment and the final ranking shown in Table 1.
Following the preliminary assessment, the work group
undertook to develop background papers describing the environ-
mental problems, as well as impacts of the problems on
ecosystems. We arranged for an outside panel of ecological
experts to comment on the workgroup's approach and indepen-
dently assess the environmental problems. We worked on
developing a more systematic ranking scheme. We also
explored the possibility of determining the relative ability
of different ecosystems to resist structural and functional
displacement and to recover from damage. We concluded that
it was not feasible to evaluate an ecosystem's vulnerability
independent of pollutant stresses.
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Table 4
Preliminary Assessment by EPA Work Group
of Problems by Ecosystems
Key;
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= no effect
= unknown
= low
= medium
= high
= not rated)
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1 1 1 1 1 1
1 1 1 1 1 1 II 1 1 1 1 1 1
1 Criteria air
pollutants
2/3 Hazardous/toxic
air pollulants
6 Radiation - other
than radon
7 Ozone depletion
8 CO2/global warming
9/10 Point sources
to surface water
11 Nonpoint sources
to surface water
12 Contaminated Sludge
13/14 Physical
alteration-aquatic
16 Active hazardous
waste sites
17 Inactive hazard-
ous waste sites
18 Municipal nonhaz-
ardous waste sites
19 Industrial nonhaz-
ardous waste sites
20 Mining
21 Accidental release
of toxics
22 Oil spills
23 Releases from
storage tanks
24 Other ground water
contamination
25-27 Pesticides
28 New toxic
chemicals
29 Biotechnology
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Assistance from a Panel of Scientific Experts
At our request, the Ecosystems Research Center at Cornell
University, an EPA Center of Excellence sponsored by the
Office of Research and Development, convened a panel of
ecological experts to conduct a two-day workshop and provide
us with an independent ranking of ecological risks. The
panel, which met at EPA headquarters on October 28-29, 1986,
consisted of 10 ecologists selected to represent the variety
of major ecosystem types in the United States. The list of
panel members appears in Table 5.
The primary objective of the panel was independently to
evaluate the potential of the environmental problems for
causing ecological damage. The panel initially addressed the
list of environmental problems as modified by the Ecological
Risk Workgroup. The panel discussed the limitations of both
problem categorization and the background information supplied
by the workgroup. The panel felt that the listed problems were
not of comparable categories, and that the problems, as defined,
were not primarily related to types of environmental stresses.
Individual categories often contained many different types of
environmental stresses.
To compare the ecological effects from the problem areas,
the panel concluded it would be necessary to both (1) evaluate
the potential ecological impacts from different environmental
stresses and (2) evaluate the contribution of various anthropo-
genic stresses with respect to their magnitude, frequency,
duration, form, and spatial distribution. Although the panel
felt they collectively had the expertise to perform the first
type of evaluation, they felt that they could not perform the
second type of evaluation. The draft background papers supplied
by the workgroup were not considered to be adequate to allow a
comprehensive understandinq of the contributions of stress
agents from the various environmental problem sources.
Thus, the panel decided to identify anthropogenic
stresses to ecological systems and to advise us on the potential
for ecological effects from each type of stress. The panel
began by identifying a comprehensive set of anthropogenic
stress agents, including those associated with the listed
environmental problems. The stress agents represented a full
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Table 5
Cornell Ecosystems Research Center
Panel of Experts
Dr. Mark A. Harwell, Ecosystems Research Center, Cornell
University, Ithaca, New York. (Chairperson)
Dr. Jim Detling, Natural Resource Ecology Laboratory, Colorado
State University, Fort Collins, Colorado.
Dr. Katherine Ewel, Institute of Food and Agricultural Sciences,
University of Florida, Gainesville, Florida.
Dr. Robert Friedman, Office of Technology Assessment, U.S.
Congress, Washington, D.C.
Dr. W. Frank Harris, Division of Biotic Systems and Resources,
U.S. National Science Foundation, Washington, D.C.
Dr. Robert Howarth, Section of Ecology and Systematics,
Ecosystems Research Center, Cornell University, Ithaca,
New York.
Dr. John R. Kelly, Ecosystems Research Center, Cornell
University, Ithaca, New York.
Dr. Michael Pilson, Marine Ecosystem Research Laboratory,
University of Rhode Island, Kingston, Rhode Island.
Dr. John Schalles, Department of Biology, Creighton University,
Omaha, Nebraska.
Dr. Richard Wiegert, Department of Zoology, University of
Georgia, Athens, Georgia.
Ms. Roxanne Marino, Section of Ecology and Systematics,
Ecosystems Research Center, Cornell University,
Ithaca, New York. (Workshop coordinator)
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i-anoe of ecological stresses, including some not presented
by the problems we addressed. These stress agents appear in
Table 6, as well as in the panel's full report which appears
as an appendix in Part IV.
The panel selected a set of types of ecosystems to
consider for potential effects associated with each stress.
The criteria for ecosystem selection were (1) to have as few
categories as possible, while maintaining sufficient resolu-
tion so that differential ecological response could be assigned,
and (2) to develop categories that nonspecialists would
readily recognize. The list of ecosystems is presented in
the panel's report and in modified form in Table 6. (This
categorization of ecosystems is guite similar to, but different
in many respects from, the categorization we used in our
initial assessment.) The panel also separated the scale of
ecological effect associated with the stress agents into
three levels, biosphere, regional and local ecosystems.
The panel then evaluated the potential of each anthropo-
genic stress for damaging each ecosystem, and the intensity
of the potential damages. As stated above, they did not
assess how extensively each stress is currently harming each
ecosystem. With this approach the Panel was not limited by
the insufficient information provided concerning sources and
exposures. Estimating actual rather than potential effects
would depend on the nature, intensity, duration, and freguencv
of the stresses actually applied to each ecosystem. The
approach also allowed the panel's results to remain applicable,
even as changes occur in the future in the anthropogenic
sources and conseguent exposures. Table 6 is an abbreviated
and reformatted version of the expert panel's consensus as
to the potential ecological effects of stress agents on
ecosystems. For the panel's own detailed statement of its con-
clusions as presented to us, together with explanatory notes,
see pages 19-30 of the panel's report.
While the panel did not address the relative risk of a
particular environmental problem, they did identify the most
important environmental stresses at the biosphere, regional
and local scales, together with an indication of the problem
areas associated with these stresses. Table 7 of this report,
taken directly from the panel report, presents this information.
For example, they considered toxic organic chemicals transported
through surface water systems as of high ecological importance
at the local ecosystem level, and noted that this stress
could result from industrial effluents, nonpoint-source
runoff, waste disposal sites, and other problem sources.
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Table 6
EPA Summary of
Expert Panel's Rankinq of Stress Agents by Impact on Ecosystems
ECOSYSTEMS:
STRESS AGENTS;
Water Sources;
BOD
toxic organics
pesticides, herbicides
chlorination products
toxic inorganics
nutrients
microbes
turbidity
acids
oil & petroleum products
thermal pollution
entrainment and
impingement
Lakes
Streams
Wetlands
- isolated
Wetlands
— Freshwater-
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M
1
He
m-h
He
m-h
H?
m-h
M?
m-h
M-H
1-m
~
L
1
RC
m
-
Me
1-m
- flowing
Wetlands
- saltwater
Estuaries
Near-coastal
Marine
Open
and
Ocean
Coniferous Forest
Estuarine
M
1
He
m-h
He
m-h
H?
m-h
M?
m-h
M?
1-m
—
L
1
He
m
M
m
Me
1-m
"
M
1
He
m-h
He
m-h
R?
m-h
M?
m-h
Me
1-m
—
L
1
"~
M
m
Me
1-m
"™
He
1-m
He
m-h
He
m-h
H?
m-h
H?
m-h
He
1
—
Me
1
L
H?
1-m
Me
1-m
7
L
Me
m-h
Me
m-h
M?
m-h
L?
m-h
Me
1
He
1-m
~
H?
1-m
™
^
^~
?
?
7
?
™
—
~
—
7
~
••
Deciduous Forest
— Te
Grassland
| Desert/Semi-arid
1
jrrestri<
1
No
Alpine/Tundra
al —
Ecolog ical
Effect
Key;
X-
x
X
x-
-Intensity of ecological effect that potentially could occur.
H = High
M = Medium
L = Low
- = No ecological effect
c = Certain or probable ecological response
? = Uncertain ecological prediction because of insufficient
understanding or because of infrequent ecological response
-Time of Ecosystem Recovery once the stress is removed.
1 = years (0-10 years)
m = decades (10-100 years)
h = centuries (100-1000 years)
i = indefinite ( more than 1000 years)
"FOOTNOTE CONTINUED ON NEXT PAGE
-------
Table 6 (Continued)
ECOSYSTEMS;
Lakes
Streams
| Wetlands - isolated
Wetlands - flowing
Wetlands - saltwater
Estuaries
| Near-coastal
-Freshwater | Open Ocean
STRESS AGENTS;
Air Sources;
gaseous phytotoxicants
acid deposition
air deposition of
toxics
greenhouse gases
ozone-depleting gases
Terrestrial Sources;
pesticides & herbicides
solid matter
toxic organics &
inorganics
microbes
Other Environmental
Problems;
radionuclides
habitat alteration
introduced species
b iotechnology
groundwater
contamination
-
L-H
m
L
h
He
h-i
H?
-
L-H
1-m
L
h
He
h-i
H?
7
— M
— m
-
He
h-i
H?
Coniferous Forest
Marine and
7
-
-
He
h-i
H?
Es1
?
-
-
He
h-i
H?
:uar:
-
L
m
7
He
h-i
H?
.ne —
-
7
7
He
h-i
H?
-
7
7
?
H?
Deciduous Fore
— Te
He
m
He
m
7
He
h-i
H?
Grassland
jrres
He
m
He
m
7
He
h-i
H?
Desert
1 Al
! 1
s trial
1 1
L
1
L?
1
7
He
h-i
H?
L
m
-
7
He
h-i
H?
H?
m
L?
m
7
He
h-i
H?
Alpine/Tundra
—
He
H?
?
'
—
He
H?
?
'
—
He
H?
7
?
—
He
H?
?
'
—
He
H?
7
?
—
He
H?
?
7
-
Lc
H?
7
"™
—
~™
~"
7
™~
™
He
H?
7
^
—
He
H?
7
^
—
He
H?
7
^
-"
He
H?
?
•M
—
He
H?
?
""*
The ecosystem groupings "lakes", "streams" and freshwater "wetlands - isolated"
represent both "buffered" and "unbuffered" categories used by the expert
panel. This accounts for the two different potential risks shown for those
groupings for the stress agents "nutrients" and "acid deposition."
-------
TABLE 7
Scale of potential ecological effects
High ecological
importance
biosphere
• global climate changes
from greenhouse gases (8)
regional
• regionally transported
gaseous toxicants (1)
• acid deposition (1)
' habitat alteration
(13-14)
ecosystem
• locally transported
gaseous toxicants (1,2)
• toxics in surface water
(9,10,11,12,21,22,28)
• pesticides, herbicides (25)
•nutrients (9,10,11)
• acid inputs to surface waters (9,10,20)
•oil (9,10,11,20,22)
• habitat alteration (13-14,20)
Medium
ecological
importance
•oil (9,10,11,20,22)
• toxics in water
(9,10,11,16,17,28)
• herbicides, pesticides (27)
• B.O.D. (9,10)
turbidity (11,20)
Unknown but
potentially very
important
• uv-B from ozone depletion (7) • biotechnology (29)
1 groundwater contamination
(12,16,17,18,19,20,23,24)
'Chlorination(9,10)
-------
APPLICATION OF THE RANKING METHODOLOGY
Following the panel evaluation, the workgroup conducted
its independent risk assessment of 22 problems, employing much
of the panel approach.
Each of the environmental problems was assigned to a work
group member or other person, usually someone representing the
relevant EPA program office. Following a basic outline, each
writer was to prepare a background paper that discussed the
ecosystem risks imposed by the assigned environmental problem.
The papers were to emphasize sources, exposure levels and
risk, both to allow an evaluation of risk and to provide support
for the ranking of the problem. Specifically, the writers
were directed to:
o Use the same stress agents and ecosystems
as the expert panel did;
o Describe the assigned problem's sources and the
exposures created by those sources, and estimate the
problem's geographic scale (biospheric, regional, or
local);
o Assess the ecological impacts of the stresses, including
the ability of ecosystems to recover once the stress
are removed; (while writers and workgroup members
were not reguired to accept the panel's evaluation of
the potential damage from individual stresses to
individual ecosystems, the panel's evaluation was
given great weight).
0 Note the degree that the problem is currently control-
led, and the expected level of control in the near
future;
o Characterize the guality of available information; and
o Provide an evaluation of the overall importance of
the environmental problem.
The workgroup members were asked to review these
problem papers and, using the same basic approach as in the
problem papers, to provide an aggregate personal ranking
for each of the problems. They were urged to base their
ranking on information contained in the background papers —
as opposed to their personal perceptions. The workgroup
-------
members were provided a blank form that allowed them to
develop an aggregate rank based on rankings for each
ecosystem. There were no prescriptive instructions on how
to assess the seriousness of damage to ecosystems, but members
were urged to consider changes in ecosystem structure and
function, and time for recovery after removal of stress.
The workgroup met on December 1, 1986, to develop a
final consensus ranking. Most individual members' aggregate
rankings used a subjective analysis of the information in
the background papers, as well as personal knowledge. The
information used to develop the background papers was highly
variable, resulting in rankings being made on a somewhat
unegual data base.
The individual members' rankings of each problem were
then tabulated according to an overall classification of the
problem as high, medium or low. The workgroup rankings
were determined by simple cluster analysis of individual
members' rankings, done by visual inspection. While indivi-
dual members' evaluations of risk from a problem to a particu-
lar ecosystem varied somewhat, there was good agreement as
to the overall high, medium or low level of risk presented
by the problems. The workgroup members then discussed the
results of the cluster analysis and reached a consensus
ranking, shown in Table 1.
The work group also arrayed the high-medium-low ranking
of environmental problems according to the geographic scale
of impact — local, regional and biospheric. This three-by-
three matrix is shown in Tab'e 2. The work group found it
more difficult to reach a consensus regarding the scale of
impact.
After classifying the problems into high, medium, or low
categories and establishing geographic impact scales, the
workgroup tried to rank the problems within the high, medium
and low categories. This proved to be very difficult, primarily
because of insufficient information. The workgroup did,
nevertheless, group the eight problems in the high category
into three rank groupings, and the eight problems in the medium
category into two rank groupings, as shown in Table 1.
As indicated previously, three problems - new toxic
chemicals, biotechnology and discarded plastics - were not
ranked due primarily to uncertainty about the risk presented.
As noted above, ocean dumping and incineration were inadver-
tently omitted from evaluation and ranking.
-------
Part III
OBSERVATIONS AND COMMENTS
This project was designed and carried out to meet
specified institutional objectives and needs. As a necessary
condition of achievinq those objectives, a number of constraints
or limitations were imposed on the workgroup; these have been
described and discussed in previous portions of this report.
In order to fully understand and evaluate the scope and
importance of the environmental impacts considered in this
report, it is critical to understand the larger environmental
context in which these impacts occur and the institutional
context which shapes and limits EPA's response to them.
These two areas are explored in some detail below, along
with a number of comments on methodological problems associa-
ted with ranking ecological effects.
THE ENVIRONMENTAL CONTEXT
The stresses and problems this workgroup evaluated do
not affect ecosystems one at a time nor within the neat
categories to which we have assigned them. Moreover, we have
not dealt with all classes or types of stresses to which
these systems are being subjected.
Perhaps the single most important stress, which tends to
eclipse most of the others for most ecosystems, is the
alteration — including outright destruction — of habitat.
In this evaluation, we considered only a limited subset of
this principal threat — namely, the physical alteration of
aguatic habitat and, to a lesser and indirect extent, the
impacts that sea level rise, siting of various waste management
facilities, and mining have on habitat. Conspicuously absent
from this list are th~ widespread and growing physical impacts
of agricultural conversion, silvicultural practices and
conversion of mixed mature stands to monocultures, grazing,
consumptive removal of surface and ground water, human foot
traffic (e.g., hiking trails in fragile alpine areas), general
human disturbance and noise, and the construction of highways,
housing, factories, shopping centers, and many other structures.
Not only do these direct physical assaults modify or
destroy habitat outright, they also tend to make natural
communities much more susceptible to stresses engendered by
the environmental problems that we evaluated. We know, for
example, that fragmented or structurally impaired natural
communities lose elasticity and/or resilience and are,
therefore, considerably more vulnerable to the effects of
toxic pollutants.
-------
Conversely, we also know that ecosystems stressed by
pollution are far more vulnerable to the adverse consequences
of climatic changes, pests, or the introduction of exotic
species. In each of these cases, the reasons for this
increased vulnerability are fairly well understood. Natural
communities have evolved in intimate relationship with their
abiotic environment — soils, water, and climate — and have
developed complex structural and functional characteristics,
such as biogeochemical cycles and food webs that both sustain
and define them. Any changes in structure or function due to
an external stress upsets the delicate equilibrium inherent
in the ecosystem, leading either to increased vulnerability to
other stresses or to a shift to a new equilibrium state, or both,
Such impacts may interact additively, synergistically,
or antagonistically, but our knowledge in this area is so
limited as to generally preclude prediction. The results,
however, are more predictable — depletion of genetic pools,
change to another community type (usually a less complex,
more impoverished one), loss of substrate, and significant
changes in hydrologic cycles, to name a few. Thus, it is
critical that we not only keep in mind this larger context as
we discuss particular environmental problems, but also that
we support those programs of other agencies and levels of
government that address the problems that we cannot.
THE INSTITUTIONAL CONTEXT
EPA in practice is much more a "pollution control"
agency than an "environmental protection" agency. EPA does
not place much emphasis on some of the types of impacts
considered by this work group. (A few notable exceptions
are to be found in the programs focusing on wetlands, pesti-
cides, and water guality.) Recognizing this reality is
critical to fully understanding the results of this effort,
since it limits both the data and information necessary for
conducting this assessment and EPA's capability to respond
to the environmental problems identified.
This situation is not too surprising when one considers
the historical roots of EPA and its authorities. In the
immediate wake of Earth Day (April 1, 1970), when this agency
was formed, the principal popular and political impetus for
its creation was the alarming recognition of the impact of
toxic chemicals on our environment as detailed in Rachel
Carson's Silent Spring. Perhaps of equal importance is the
fact that the primary responsibilities for protecting
fish, wildlife, forests, and other natural resources were
already vested in other agencies, notably the Departments of
Interior and Agriculture. Even in the 1970 reorganization,
-------
<-he President and Congress chose to place a numnber of
environmental protection responsibilities not in EPA, but in
NOAA, an arm of the Department of Commerce. The result was
that EPA's initial set of responsibilities was somewhat biased
toward the public health side of the spectrum, though significant
environmental responsibilities are found in some of our
legislation, particularly the water and pesticides laws, and
are embodied in the mandates of others.
As new issues emerged and the Congress responded with
legislation, the shift away from environmental (i.e., natural
ecosystem) emphasis and toward public health protection
intensified (with the notable exception of the surface water
protection programs). By the early 1980's, it had reached the
point that nonhuman health concerns were openly given little
regard. While this attitude was far from universal within
EPA, it was sufficiently dominant to influence both policy and
program development, and it had a clear impact on staff recruit-
ment. Thus, we find ourselves now with an institutional "culture1
that subordinates true environmental issues to a poor second,
which in a climate of resource constraint freguently eguates to
simply "falling off the list" completely. Of probably more far-
reaching conseguence, however, has been the impact of this bias
on a variety of EPA activities. Today we find ourselves with a
rudimentary data base on actual environmental effects (or
even ambient conditions), and we lack the tools and methods
needed both to assess environmental effects and to evaluate
their conseguences.
In the last several years some reversal of this overall
trend has been seen, tangible examples being the formation of
the Offices of Marine and Estuarine Protection and Wetlands
Protection. The change has been attributed to a variety of
factors, including the interests of current top management, the
emergence of new issues with predominately environmental
conseguences (for examples, forest decline and the effects of
acid deposition on lake fauna), and some popular "rediscovery"
of certain issues, such as biotic impoverishment and the
threatened loss of entire ecosystems.
Thus, although the effects of this historical bias are
probably not permanent, they certainly affect current EPA
priority-setting and policy formulation. This was evidenced,
for example, by this workgroup's difficulty in locating both
data and expertise within EPA for carrying out the evaluation
of ecological risk.
-------
It can be argued, perhaps, that this situation may
not actually be a problem, given the responsibilities
and capabilities of other agencies. If other federal agencies
have the primary responsibilities for protecting natural
resources, including flora and fauna, why is it critical that
EPA play a major role in these areas? We believe that there
are important reasons for EPA to strengthen its capability
to protect environmental values other than human health.
First, EPA does have a number of direct statutory
responsibilities in this regard. In fact, all of EPA's major
statutes, except the Safe Drinking Water Act, reguire EPA
in some fashion to take into account pollution effects other
than those to humans. In some cases, this may be a very
direct and explicit responsibility, such as in section 404 of
the Clean Water Act (wetlands protection) or Title I of the
Marine Protection, Research and Sanctuaries Act (ocean dumping).
In others, it may be much less direct and of obviously lower
Congressional priority, such as the national Secondary Ambient
Air Quality Standards. Moreover, in most of its activities,
EPA like any other Federal agency must comply with a number
of externally administered statutes or directives that
emphasize protecting the natural environment. These include
the Endangered Species Act, the National Environmental Policy
Act, and the Executive Orders on Wetlands Protection (E.O.
11990) and Floodplain Management (E.O. 11988).
These responsibilities have not been, and cannot be,
delegated to any other agency. More important, they are not
generally duplicative of the environmental protection
responsibilities of other agencies, since they focus on the
protection of the environment primarily from chemical pollution,
as opposed to physical manipulation or destruction. Because
of the breadth of sources, pollutants, exposure pathways, and
ecosystems involved, it is necessary for EPA to maintain a
broad expertise and capability to deal with environmental
processes and effects in natural communities.
Second, even in those areas where another agency is
assigned the primary role of protecting the environment, EPA
can and frequently does play an important supporting role to
the other agency. This support can take a variety of forms,
such as assisting the Department of Agriculture in developing
an integrated pest management program for the national forests
or rangeland, and in developing regulations to implement the
conservation programs of the "Farm Bill" (i.e., the conservation
-------
reserve, "sodbuster," and "swampbuster" programs); working
with NOAA in establishing marine monitoring and research
programs; and reviewing a variety of other agency programs
and activities and helping them formulate less environmentally
damaging alternatives. These may include highways (DOT),
surface mining (DOI), water resource development (Corps of
Engineers, USDA/SCS, DOI/Bureau of Reclamation), deep sea
mining (NOAA), hydroelectric power development (FERC), and
fossil and nuclear energy development (DOE, NRC).
In each of these examples, EPA's important supportina
role is based upon its knowledge and expertise in pollution
control as applied to natural ecosystems. Not only is our
pollution - related expertise necessary to the other agencies
in meeting their objectives, but also their expertise and
actions help us meet our own broad mandates for protecting
the whole environment.
METHODOLOGICAL PROBLEMS
As indicated previously in this report, the work group
encountered a number of difficult methodological problems.
Some of the problems reflect the very complex nature of
evaluating ecosystems, but other problems result from
insufficient emphasis throughout the Agency on ecological
matters. Summarized below are some of the more critical
problems the work group had to deal with.
No Established Methodology Exists for Evaluating Ecological
Risks
Most Agency risk assessment activities have dealt with
human cancer or other human health problems. This focus on
human health, especially on a single disease endpoint (cancer
in humans), as well as the focus on the impacts of individual
chemicals, facilitated development of guantitative human
health risk assessment capabilities. The ecological sciences
have not produced — and may never produce - similar guanti-
tative endpoints.
Ecological risk assessment is emerging as an approach to
analyzing environmental problems. However, it is in a concep-
tual stage and has not produced the needed methods, models,
and data bases for routine use. Trying to assess ecological
effects by using methods that were developed to address
human health impacts (i.e., hazard x exposure = risk) is a
reasonable conceptual approach but not an easy task. The
earlier approach to impact assessment is less formalized
and generally does not use probabilistic, guantitative methods.
Instead, likely or possible impacts are characterized in
gualitative terms, based on professional scientific judgement.
-------
Ecosystem Science is Complex and Predictive Tools are not
Available
Although scientific understanding of ecosystem science
has grown considerably in the past few decades, this body of
knowledge is not sufficient to be assembled and "scaled up"
for this project. Ecosystem science is truly an integrative
discipline that is based on understanding of component disci-
plines (chemistry, physics, biology, etc.). Its relatively
recent origin explains why ecosystem science is still at a
descriptive stage and has not yet produced a body of generali-
zable facts. Much is known about individual ecological
impact on sites that have been well studied, but such results
cannot be generalized. Results from one study at a particular
site can not be extrapolated to other sites because under-
standing at the ecosystem level is just too limited.
The complexity of ecological interactions poses a
substantial obstacle to predicting with much certainty the
results of specific impacts. This complexity involves the
dynamics of each plant and animal population, the
relationships among populations in the plant-animal communities,
and the interactions of the biota with the abiotic environment.
Ecological processes, such as nutrient cycling, are often
poorly understood. The complexity of ecosystem science has
resulted in a substantial use of scientific judgement to
complete this assessment. This violates, to some degree,
the intent of strict risk assessment, which is to document
the assumptions and data that were used to reach conclusions.
Ecological Risks are Difficult to Define
Ecological risks cannot be characterized using
common, easily understood measures, such as mortality (used for
cancer risk) or economic terms (used for welfare risks). The
broad concept of "ecological integrity" (protecting existing
conditions) is too general to apply.
In the absence of standard measures of ecosystem "health"
(e.g., measures that are eguivalent to diagnosing human
disease — fever, white blood cell count, etc.), a confusing
diversity of endpoints have been suggested. The confusion
derives, in part, from the fact that the ecological attributes
for which public protection is to be provided have not been
chosen. Also, scientists have not documented adeguately
the values of ecological systems and functions. The "fisha-
ble" goal that the Clean Water Act supplies for the Nation's
surface waters is an example, albeit a limited one, of an
environmental endpoint in current use.
-------
Scientific Uncertainties are Inherent in Ecological
Risk Assessment
Considerable uncertainty exists in most aspects of
ecological risk assessments. This includes: (1) identifying
the appropriate component stress agents for each environmental
problem; (2) characterizing the sources, emissions, and
anticipated regulatory controls; (3) describing the movement
and transformation of the stress agents in the environment
and their ultimate fate; (4) assessing ecological effects in
a comprehensive manner (i.e., direct and indirect effects at
various levels of ecological organization — population,
community/ and ecosystem — and spatial and temporal scales);
and, (5) estimating the reversibility of impacts in terms of
how guickly or whether ecosystem recovery occurs.
Some of those uncertainties are similar to those operative
in assessing human health risks (e.g., exposure assessment models)
Some are more difficult, such as understanding
ecological effects.
Estimating the Exposure of Ecosystems to Stress Agents
is Particularly Difficult
As in assessing human health risk, exposure to hazard
rather than the hazard itself often controls the final
ecological risk estimates. Thus, if exposure is low, potential
damage may not occur. Because humans are point-source
receptors, estimating how extensively they are exposed to
hazards is easier than for ecosystems that may cover large
geographic areas. The large size of ecosystems, as well as
their heterogeneous characteristics, also mean that exposures
can be guite variable spatially, making assessment even more
difficult. Also, most ecosystems are composed of many
populations of organisms that have differing sensitivities to
impacts, so that understanding the exposure to specific parts
of the system (e.g., benthic organisms or predators) may be
important. Overall, estimating ecosystem exposure is extremely
difficult for most of the environmental problems and is a
significant cause of risk assessment uncertainty.
Ecological Risk Information is Limited
Because there is no standardized ecological risk assess-
ment methodology, it is not clear what data and information
are needed to analyze risks to ecosystems in a consistent
manner. Information that does exist is difficult to access
because it is normally not assembled in ways that make it
readily available and usable. Using data collected
for different purposes (e.g., laboratory toxicological data
or urban monitoring data) poses additional problems. Most
-------
environmental information has not been collected and
analyzed in a manner that facilitates (or even permits)
analysis of ecological risks (e.g., most monitoring efforts
have not been designed to determine exposure to natural
ecosystems).
The List of Environmental Problems is Unsuitable for Assessing
Ecological Risk
The 31 environmental problems employed in the
Comparative Risk Project reflect EPA's current priorities and
represent existing EPA programs. Although EPA's statutory
responsibility in these areas typically includes protection
of both human health and the environment, the EPA regulatory
programs (and thus the problem areas of this project) are
oriented disproportionately toward human health concerns.
The outcome of ranking ecological risks depends on which
problems are considered and how they are described and grouped.
A few examples illustrate this point:
o Several major ecological risks are not included on
the list because EPA does not have direct statutory
authority. (For example, conversion of natural eco-
systems through urbanization and agricultural
development, timber harvesting policies in National
Forests, marine mammal hunting, and introduction of
exotic species were not on the list.)
o The size of a risk category tends to affect its ranking.
Land-based waste disposal is very finely subdivided
into two kinds of Subtitle n landfills, Subtitle C
landfills, and abandoned and uncontrolled landfills;
this tends to lower each individual rank. On the
opposite extreme, all toxic air pollutants make up
an extremely broad category.
The National Focus of the Project Overshadows Global and Local
Perspectives
Damage may occur at various levels of ecological
organization, ranging from harm to plants and animals, to
global, biospheric changes. The Comparative Risk Projects's
national assessment takes a medium-level cut at the
problem and tends to miss the smaller-scale and larger-
scale problems. Local impacts, such as loss of endangered
species, can be significant; and so can large-scale
impacts, such as loss of global genetic diversity. While
-------
the national approach is useful for the purposes of this
exercise and makes sense for certain categories of risk
(e.g., consideration of only health and welfare in the United
States) it does not for some kinds of ecological risks, such
as those that transcend political boundaries (e.g., migratory
birds and fish, impacts to the oceans, atmospheric alteration)
A few examples of the conseguence of the national-level
assessment are:
o Impacts on the ocean ecosystem tend to be ranked
low if only U.S. sources are considered. (As
noted above, the workgroup did not evaluate the
impacts of ocean disposal.)
o Habitat alteration that is occurring throughout the
world and the related loss of genetic diversity were
not considered.
o The only global issues evaluated were atmospheric -
- stratospheric ozone depletion and global warming —
and the issue of U.S. sources versus global sources
was not adeguately treated.
-------
Part IV
Appendix A: "Ecosystems Research Center Workshop on
Ecological Effects From Environmental
Stresses", Cornell University, Dec. 1986
Appendix B: Background Papers for each environmental
problem
-------
Appendix A
-------
Ecosystems Research Center
Workshop on Ecological Effects from Environmental Stresses
A Contribution to the EPA Comparative Risk Project's Ecological Risk Workgroup
December 1986
Mark A. Harwell
John R. Kelly
Ecosystems Research Center
Cornell University
Ithaca, New York 14853
-------
Preface
The U.S. Environmental Protection Agency (EPA) is conducting a Comparative Risk
Project, an ad hoc, intra-agency effort seeking to examine the full gamut of environmental
risks associated with potential impacts on human health and welfare interests as well as on
ecological systems. An important facet of the project has been the examination of a
common list of environmental problem areas by each of the groups interested in specific
types of effects. One component of the project has been to focus on ecological issues
within the Ecological Risk Workgroup - a group of EPA staff who examined the list of
environmental problem areas, estimated the ecological effects of each on a set of ecosystem
categories, and ranked the problems with respect to the magnitude of estimated current or
projected ecological effects. This EPA group decided to seek outside expertise to conduct
an independent evaluation of the potential ecological effects, comment on the ranking
scheme and methodology developed by the EPA group, and provide additional comment on
the role EPA should play in addressing important ecological issues.
The Ecosystems Research Center (ERC) at Cornell University, an EPA Center of
Excellence for ecological research, was asked to assemble such a group of experts in a
workshop. This workshop was held at EPA headquarters on 28-29 October 1986, and
consisted of 10 scientists, selected to represent the variety of major ecosystem types in the
United States, and whose expertise includes ecosystems-level stress ecology. (See
Appendix B for the list of participants.) The results of the workshop deliberations are
presented in this report, which reflects the consensus of the participants.
This publication is ERC-140 of the Ecosystems Research Center (ERC), Cornell
University, and was supported by the U.S. Environmental Protection Agency Cooperative
Agreement Number CR-812685. Additional funding was provided by Cornell University.
The work and conclusions published herein represent the views of the authors, and do not
necessarily represent the opinions, policies, or recommendations of the U.S.
Environmental Protection Agency.
-------
Background
The U.S. Environmental Protection Agency (EPA) has underway an ad hoc, intra-agency
effort to examine the variety of environmental problems under EPA purview facing the
United States with respect to different endpoints of concern, specifically human cancer
risks, human non-cancer health risks, welfare effects, and ecological effects. This activity
is under the aegis of the Comparative Risk Project, and each category of risk is being
evaluated by a separate subgroup of the project looking at a common list of environmental
problems. The list of environmental problems was developed by the Comparative Risk
Project into the thirty-one categories presented in Table 1.
The particular focus pertinent to this report is on the activities of the EPA Ecological Risk
Workgroup, which consists of EPA staff representing a variety of offices in the Agency.
That group slightly altered the list of thirty-one by: a) combining items 9 and 10 to include
both direct and indirect point-sources into surface waters; b) combining items 25 and 27 to
include all risks from pesticides to the environment; c) redefining items 13 and 14 to
constitute any direct physical alteration to surface water systems (e.g., dredging and
filling); d) expanding item 11 to include in-place toxics in sediments of surface water
systems; e) expanding item 20 to include all effects associated with resource extraction; and
f) eliminating items 4,5,15,26,30, and 3.1 as having no relevance for ecological effects.
The resulting list of environmental problems (see Table 5) was examined by the EPA
Ecological Risk Workgroup for effects on ecological systems. A classification scheme for
ecosystems was prepared, consisting of fifteen ecosystem types for marine, estuarine,
freshwater, and terrestrial ecosystems, plus four additional categories for special issues.
The group assigned a qualitative score for estimated effects from each of the environmental
problem areas on each of the ecosystem categories; the resulting matrix is included as
Appendix A. The EPA group also prepared a set of position papers on most of the
environmental problem areas, each consisting of a few-page description of the nature of the
problem and some comment on the ecological risks associated with it.
The EPA Ecological Risk Workgroup decided to enlist outside expertise to assist the
evaluation of the ecological risks from the environmental problem areas. The Ecosystems
Research Center (ERC) at Cornell University was asked to assemble a group of scientists
representing expertise in a wide variety of ecosystem types in order to: a) perform an
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Table 1
EPA Comparative Risk Project List of Environmental Problems
1.) Criteria air pollutants from mobile and stationary sources - includes acid precipitation
2.) Hazardous/toxic air pollutants
3.) Other air pollutants - e.g., fluorides, total reduced sulfur
4.) Radon - indoor pollution only
5.) Indoor air pollution - other than radon
6.) Radiation - other than radon
7.) Substances suspected of depleting stratospheric ozone layer - e.g., chlorofluorocarbons
8.) CC>2 and global wanning
9.) Direct point-source discharges to surface water - e.g., industrial sources
10.) Indirect point-source discharges to surface water - e.g., POTW's
11.) Non-point source discharges to surface water
12.) Contaminated sludge - includes municipal and scrubber sludges
13.) Inputs to estuaries, coastal waters, and oceans from all sources
14.) Inputs to wetlands from all sources
15.) Drinking water at the tap - including chemicals, lead from pipes, biological
contaminants, radiation, etc.
16.) Active hazardous waste sites - includes inputs to groundwater and other media
17.) Inactive hazardous waste sites - Superfund; inputs to groundwater and other media
18.) Municipal non-hazardous waste sites - inputs to groundwater and other media
19.) Industrial non-hazardous waste sites - inputs to groundwater and other media
20.) Mining wastes - e.g., oil and gas extraction wastes
21.) Accidental releases of toxics - all media
22.) Accidental oil spills
23.) Releases from storage tanks - includes aboveground and underground storage
24.) Other groundwater contamination - includes septic tanks, road salt, injection wells
25.) Pesticide residues on food eaten by humans or wildlife
26.) Application of pesticides - includes risk to pesticide workers as well as consumers
who apply pesticides
27.) Other pesticide risks - including leaching and runoff of pesticides and agricultural
chemicals, air deposition from spraying, etc.
28.) New toxic chemicals
29.) Biotechnology
30.) Consumer product exposure
31.) Worker exposure to chemicals
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independent evaluation of the potential for ecological effects from each environmental
problem; b) critique the methodology and results of the EPA Ecological Risk Workgroup to
date in its ecological risk assessments; and c) provide additional comment on the role EPA
should play in addressing ecologically important problems that currently are not a major
activity within EPA. The EPA group provided the outside experts with the initial EPA
ranking of the environmental risks and with copies of the draft position papers covering
environmental problem areas 1, 2, 3, 6, 7, 8, 9/10, 11, 12, 13/14, 16, 18, 19, 20, 24,
25/27,28, and 29.
The ERC workshop group met at EPA headquarters on 28-29 October 1986; the agenda
and list of participants are included in Appendix B. The first half-day session was left to
the EPA group to overview the environmental problem areas, and to present its
methodology and results to date; then the outside expert group met for one and one-half
days to conduct its evaluations. Consensus was reached among all of the workshop
participants on the approach to be used and on the specific ecological evaluations. The
present report reflects that consensus.
Approach
The primary objective of the workshop was to perform an independent evaluation of the
environmental problem areas with respect to then- potential for ecological effects.
Consequently, initial attention was given to the list of environmental problem areas
provided by EPA. The workshop was asked to address that specific list in order for its
results to be comparable with other evaluations within the Comparative Risk Project. Much
discussion focused on the limitations of the list and of the background information supplied
to the workshop participants. Specifically, it was clear to the workshop group that the
listed problem areas are not categorized in parallel, and that the criteria for selecting the
items on the list were not primarily related to potential types of environmental stresses.
Consequently, individual categories often contained many different types of environmental
stresses. For example, category 1 includes "criteria pollutants", those pollutants identified
hi the Clean Air Act for which National Ambient Air Quality Standards are required (SO2,
NOX, O3, CO, Pb, and particulates). The types of ecological stresses associated with this
single category vary widely, from local-scale deposition of a heavy metal whose primary
concern is for ecological routes to humans, to the transboundary-scale problem of acid
deposition, which has the potential for significant ecological effects on freshwater and
terrestrial ecosystems involving pH stress, aluminum toxicity, enhanced susceptibility to
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disease and pest infestations, differential effects on competitive interactions in ecological
communities, and so on. On the other hand, many classes of environmental stresses from
anthropogenic activities were categorized into more than one environmental problem area.
For example, the potential ecological impacts from xenobiotic organic chemicals that are
toxic to biota could be associated with the EPA-listed items 1, 2, 3, 9/10, 11, 12, 16, 18,
19, 20, 21, 22, 23, 24, 25/27, and 28.
The difficulty this situation presented for the ecological workshop participants was that
evaluating the relative potential ecological effects from the EPA list of problem areas would
require both: a) an evaluation of the relative ecological impacts from different
environmental stresses, and b) an evaluation of the relative contribution of each stress from
the various sources (problem areas) with respect to the magnitude, frequency, duration,
form, and spatial distribution of the anthropogenic inputs into the environment. Whereas
the workshop participants felt they collectively have the expertise to estimate ecological
effects from a variety of ecological stresses (item a), they did not feel competent to evaluate
the specific relative contribution of the anthropogenic sources into the environment (item
b), and could not fully utilize the briefing materials provided by EPA. Related to item (b),
the consensus of the participants was that whereas they received an understanding of the
breadth of environmental problems in the United States facing the EPA, they did not gain a
sufficiently complete understanding of the relative importances across various sources of
environmental problems.
Consequently, the workshop participants decided it was not possible to rank the EPA list of
environmental problem areas directly without much greater information on sources, but,
rather, to focus on item (a), drawing upon their expertise to identify the full range of
anthropogenic stresses on ecological systems and to estimate the potential for ecological
effects from each type of stress. The task of Unking this evaluation back to the initial list of
thirty-one problem areas is left to a longer, more concerted research effort in the future.
The workshop participants began from the EPA list as modified by the EPA Ecological
Risk Workgroup (Table 5), by identifying the specific types of ecological stresses
associated with each item on the EPA list. In addition, a few potential environmental
stresses were identified by the ecological workshop participants that were not incorporated
in the EPA environmental problems list; these stresses were added to make the final set of
stresses more comprehensive and not necessarily limited to activities currently under the
purview of EPA. The stress types were categorized by the agent of introduction into the
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environment (e.g., anthropogenic stresses transported by the atmosphere, inputs
transported by surface water systems, etc.). The set of ecological stresses developed by
the workshop is presented in Table 2. It should be noted that the categories of stresses are
still not fully parallel, and multiple scales of effects often remain associated with a single
stress category, as discussed previously with respect to the EPA-generated list.
Nevertheless, each category of ecological stresses was selected to represent a common
mode of exposure and type of ecological response.
The next step was to select the particular types of ecosystems to consider for potential
effects associated with each stress. The criteria for developing the ecosystem categories list
were: a) to have as few categories as possible while maintaining sufficient resolution so that
differential ecological responses could be assigned, and b) to develop categories that would
be readily recognizable by non-specialists. The resultant classification (Table 3) is quite
similar to the initial list prepared by the EPA Ecological Risk Workgroup, even though the
outside expert group did not use the EPA list as a point of departure. The ecosystem
categories differ considerably in the level of detail; in some cases, the characteristics
determining ecological responses can be readily identified. For example, for freshwater
ecosystems, strong positive correlations generally exist between acid-neutralizing capacity
(buffering) and the levels of total alkalinity and limiting nutrients; these in turn determine
the sensitivity of the ecosystem to various stresses. Similarly, a distinction between
isolated and flow-dominated freshwater wetlands was deemed appropriate, because of
well-recognized differences in the hydrologies, loading pathways, and internal properties
of these ecosystems; isolated wetlands tend to be less productive, with lower nutrient
loadings, less mixing, greater benthic stagnation, and higher levels of phytotoxic, reduced
compounds (e.g., hydrogen sulfide) in sediments. It was agreed by the workshop
participants that future efforts should concentrate on searching for alternate methods for
classifying ecosystems, including an effort at a functional characterization which could
incorporate more fully current ecological understanding in designing an ecosystem
categorization and which would more readily allow for site-specific factors that could alter
the projected stress-response relationships.
Once these categories were agreed upon, the workshop participants considered each
anthropogenic stress with respect to the potential for ecological effects on each ecosystem
type. The approach was to consider the qualities of each ecosystem as a basis for
estimating the nature and extent of potential effects if exposure by the ecosystem to the
particular stress were to occur. Such a hypothetical approach allowed the workshop not to
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be unduly limited by an insufficient information base and understanding by the participruits
concerning the nature of anthropogenic sources. In some cases, the participants felt
confident to take source information into consideration in estimating potential ecological
effects from particular stresses, but in most cases that was not feasible. Consequently, the
resulting assessment is best characterized as representing potential ecological effects rather
than reflecting the extant state of the environment. A comprehensive assessment of the
ecological risks and damages of anthropogenic activities in the United States would require
a much larger effort and much more extensive information base than available here.
Nevertheless, the accuracy of the ecological effects projections will improve significantly
with increased understanding of the nature and extent of each anthropogenic stress.
Potential ecological effects were estimated first with respect to the scale at which impacts
would likely occur: at the biosphere level, at regional (i.e., transboundary, landscape)
scales, or only at localized ecosystem levels. A nested scheme was developed, such that an
ecological effect expected to occur at the biosphere level, e.g., associated with climatic
change issues, would also be expressed as ecological effects at the regional or local
ecosystem levels. Consequently, each stress was considered for its specific effect at the
ecosystem level using the following factors:
1) the potential intensity of ecological effects, evaluated as high, medium, low, or no
effect;
2) the nature of the ecological effect, specifically: a) affecting the biotic community
structure, such as alterations in the trophic structure, species diversity or richness,
or other community-level indicators of disturbance; b) affecting ecological
processes, such as primary production, rates of nutrient cycling, decomposition
rates, etc.; c) affecting particular species of direct importance to humans, such as
for aesthetic or economic reasons, or affecting endangered or threatened species;
and d) the potential for the ecosystem to function as a vector for routes of exposure
to humans of chemicals or organisms having potential health-effects concerns;
3) the degree of certainty associated with the projections, differentiating those
circumstances where the data and understanding are sufficient for certain or
probable projections to be made versus the situation of either poorly understood
stress-response relationships or of highly infrequent occurrence of adverse
responses; and
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4) the probable time scale for recovery to occur following cessation of the stress,
estimated as years, decades, centuries, or indefinite time for recovery.
Each of these estimations was based on the collective expertise of the ecological workshop
participants, and, thus, relies on the scientific judgment of the participants rather than on
actual analyses. Now that the framework for this cross-ecosystem stress evaluation has
been established, however, it should be straightforward to extend the ecological risk
assignment to include more rigorous analyses and extrapolations from case studies and
experimental evidence. Clearly, there was insufficient time at the two-day workshop to
undertake that effort, and a continuing research activity would be needed to effect it. The
group consensus was that a continuing, second-order effort at refinement by this or a
similar group of ecologists is a high priority.
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Table 2
ERC Ecological Workshop List of Anthropogenic Ecological Stresses
Stress agents:
Air sources (anthropogenic stresses transported through the atmosphere):
• gaseous phytotoxicants - includes ozone, SC>2, NOX, etc.
• acid deposition
• air deposition of toxics - includes aerial transport of metals and volatile organics, such
as PAHs, PCBs, etc.; particularly important near urban areas from automobile
exhaust, fossil fuel combustion, etc.
• greenhouse gases - includes gases that can lead to climatic alterations through changing
the solar energy balance or the atmosphere, including CO2, N2O, CH4, CFCs, and
other gases.
• ozone-depleting gases - includes gases such as CFCs that can reduce stratospheric
ozone and consequently result in increased levels of UV-B radiation.
Water sources (anthropogenic stresses transported through surface water systems):
• B.O.D. - biological (biochemical) oxygen demand.
• toxic organics - toxic organic chemicals from anthropogenic sources; includes PCBs,
kepone, PAHs, etc.; in dissolved and paniculate states; does not include pesticides and
herbicides.
• pesticides and herbicides - includes agricultural biocides that are exported from target
agroecosystems through surface water systems.
• chlorination products - includes inorganic chlorine plus organochlorine by-products
associated with wastewater treatment.
• toxic inorganics - includes water-borne sources of lead, mercury, copper, cadmium,
cyanide, arsenic, selenium, other metals, etc.; does not include acid effects.
• nutrients - nitrogen and phosphorus.
• microbes - human pathogens.
• turbidity- includes only physical effects of particles in surface water systems.
• acids - only includes effects from lowered pH in surface waters; sources include acid
mine drainage and industrial effluents.
• oil and petroleum products - includes chronic effects and accidental spills.
• thermal pollution - especially significant source is nuclear power plants; thermal inputs
also from other power plants and industry.
• entrainment and impingement - physical effects on individual organisms as taken from
aquatic ecosystems into cooling systems of power plants and other industry.
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Terrestrial sources (anthropogenic stresses applied directly to terrestrial systems):
• pesticides and herbicides - applications directly to terrestrial ecosystems or by drift
from agricultural applications; transport by surface and groundwater systems
considered elsewhere.
• solid matter - includes physical effects only (i.e., not chemical effects) from mine
spoils, fly ash, solid waste, sludge, etc.
• toxic organics and inorganics - includes metals and organic wastes dumped directly
onto land; transport by surface and groundwater systems considered elsewhere.
• microbes - human pathogens in sludge.
Other environmental problems
• radionuclides - inputs to air, water, and terrestrial systems of radioactive chemicals.
• habitat alteration - includes any direct physical alteration to habitats.
• introduced species - deliberate or inadvertent introduction by humans of natural species
novel to a particular environment.
• biotechnology - accidental or deliberate releases of engineered organisms into the
environment
• groundwater contamination - includes all contaminants entering groundwater systems,
such as metals, toxic organics, toxic inorganics, pesticides, herbicides, radionuclides,
and microbes.
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Table 3
ERC Ecological Workshop List of Ecosystem Categories
Freshwater ecosystems
• buffered lakes
• unbuffered lakes
• buffered streams
• unbuffered streams
Marine and estuarine ecosystems
• coastal ecosystems
• open ocean ecosystems
• estuaries
Terrestrial ecosystems
• coniferous forests
• deciduous forests
• grassland ecosystems
• desert and semi-arid ecosystems
• alpine and tundra ecosystems
Wetland ecosystems
• buffered freshwater isolated wetlands
• unbuffered freshwater isolated wetlands
• freshwater flowing wetlands
• saltwater wetlands
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Results and Discussion
Ecological Effects Evaluations
The results of the workshop deliberations were collated into a matrix (Table 4), which
indicates the variety of ecosystem types considered, the variety of anthropogenic stresses
considered, the potential intensity of each ecological effect, and the prospects for recovery,
with annotation to discuss particular qualifications concerning the effects projections. It is
difficult to capture the full range of discussions and deliberations that led to characterization
of each cell in this matrix; the, footnotes for each cell reflect the discussions, but
considerably more depth was associated with the discussions at the workshop for each
evaluation. The matrix was developed by examining a single stress with respect to its
potential effects across ecosystem types; because of insufficient time, little attention was
given to comparisons of a single ecosystem category with respect to relative potential
effects from different stresses. Consequently, the matrix is most reliable for comparisons
along each matrix row, and comparisons down columns are less reliable.
The workshop participants discussed how each stress agent related to the original EPA list
of tnirty-one problem areas. As mentioned previously, the consensus was that an
insufficient basis was available for the workshop to rank those environmental problem
areas directly; however, the workshop was able to identify provisionally which ecological
stresses would potentially be associated with each environmental problem area. Another
matrix was prepared to assist in making the translation between the two lists, presented as
Table 5. Note, however, that the relative contribution by different environmental problem
areas (sources) to each ecological stress was not evaluated and cannot be inferred from the
matrix in Table 5.
However, the workshop participants felt that, whereas there was insufficient information to
evaluate in detail the source aspects of human effects on the environment, they did have
some knowledge concerning source terms and felt capable to begin to prioritize across the
variety of ecological stresses. Consequently, an initial attempt was made to identify the
priority environmental issues facing the United States currently or in the foreseeable future.
This estimation was based on subjective judgment of the participants to provide some
guidance to EPA with respect to the ecologically most important issues requiring attention.
One difficulty arose in preparing this priorities list, specifically that the environmental
stresses considered by the workshop and the environmental problem areas defined by EPA
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may affect the environment at widely differing scales, ranging from very localized
concerns, such as associated with inactive hazardous waste sites regulated under
Superfund, to very large-scale concerns, such as global-scale alterations in the climate
resulting from anthropogenic inputs of greenhouse gases into the atmosphere. Assigning a
relative importance to such widely differing scales of effects is not strictly a scientific issue,
but, rather, requires societal judgment of relative importances. For example, associated
with such judgments across scales are issues of: 1) the certainty or uncertainty of causal
relationships, including the projected intensity, timing, and duration of effect; and 2) the
relative ability to establish scientific certainty across scales relative to the probable
occurrence and time frame of the effect, given the continuance of the stress. These types of
issues could not be explored in the brief workshop period, and a single ranking across
scales was not attempted. Consequently, the workshop participants separately prioritized
ecological stresses at the three scales, i.e., biosphere, regional or landscape level, and local
or ecosystem level. The workshop identified those issues of greatest ecological concern at
each scale, defined with respect to the potential intensity of the effect, the nature of the
ecological response, the prospects for recovery, the nature of the anthropogenic source,
and prospects for mitigation or amelioration of adverse effects. Other issues of great
uncertainty, but of potentially great impact, were also highlighted by the workshop.
Finally, the numbered items in EPA's environmental problem areas list (as modified) that
might be associated with the priority ecological stresses were identified; again, however,
the relative contribution from each source to the overall potential ecological effect was not
considered. The results from this prioritization exercise are presented in Table 6.
Comments on EPA Approach
The ERC Ecological Effects Workshop participants also discussed the methodology and
results of the EPA Ecological Risk Workgroup, although much less attention was given to
this task than to the ecological effects evaluations. The EPA approach of examining
potential environmental effects across ecosystems and across environmental problem areas
is to be commended as a logical approach to make explicit the assumptions and estimations
upon which EPA priorities are established and to identify environmental concerns that may
be experiencing insufficient attention at present. Comparing human health, welfare, and
ecological risks through examination of a common list of environmental problem areas also
seems appropriate as a way to make explicit to managers the disparate issues that need to be
considered in environmental decision making. Taking the process the next step, i.e.,
assigning relative importances to the disparate types of risks, however, should not be done
by a formalized methodology, and the current EPA approach, to rely on the considered
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judgment of senior management whose responsibilities are to make those difficult choices,
is required.
The specific environmental problem areas examined in the Comparative Risk Project,
however, were not selected solely based on considerations of ecological and human effects;
in particular, the EPA list is highly non-parallel in its structure and includes items of
relevance to administrative, organizational, or political issues. This significantly
complicates the task of performing comparative risk assessments. Translating the itemized
problem areas into specific stresses that can be properly evaluated requires substantial
information concerning the sources of anthropogenic stresses. Comprehensive source
characterization would include information on the intensity, duration, and spatial extent and
distribution of the stress relative to the distribution and differential sensitivities of
ecosystems exposed to the stress. Lack of sufficient information concerning such sources
was a significant handicap to the ecological effects workshop, and it would seem that
similar problems would apply to examination of other types of risks.
A second problem with the EPA approach is the mixing of risks that occur at tremendously
differing scales of exposure and effects. As discussed previously, comparing effects on
very localized systems with effects that can transcend national boundaries is difficult and
involves issues other than strictly scientific ones. For instance, the large funding provided
by Congress for Superfund activities reflects the important political constituency there is in
the United States for concerns about possible abandoned toxic waste sites in the districts of
virtually every Congressperson. By contrast, it is more difficult to identify the political
constituency for concern about hypothetical global problems projected to be manifested in
the next several decades, such as increases in UV-B from stratospheric ozone depletion.
Weighting local concerns for environmental problems with immediate time frames versus
national concerns for environmental problems with very long time frames (by human
standards) requires appropriate societal inputs and judgment
Nevertheless, it is the consensus of the ecological experts that environmental stresses
occurring at larger scales are intrinsically of greater ecological concern because: a) such
stresses transcend ecological boundaries, exposing resistant and sensitive ecosystems alike,
making the potential ecological effects more consequential; b) larger-scale ecological
disturbances require greater times for recovery processes and have decreased chances of
eventual recovery at all; c) there is a greatly decreased opportunity for mitigation or
amelioration of large-scale ecological effects; d) smaller-scale effects, such as at the local
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ecosystem level, are concomitant with the larger-scale stresses; e) the time constants for
delays in ecological effects are increased at larger scales, substantially decreasing the
opportunities for useful information feedbacks from demonstrated ecological effects to
appropriate management actions; e) larger-scale ecological stresses are more likely to have
synergistic effects with other stresses, and the potential for subtle indirect effects may be
enhanced; consequently, there is increased probability of surprise effects that become
recognized not through predictions, but only after they occur, making regulation difficult or
impossible; f) large-scale stresses transcend national boundaries, making them more
difficult to manage and regulate effectively; and g) larger-scale anthropogenic stresses on
the environment export the ecological risk far from the activities and sources of origination,
potentially affecting ecosystems and human populations that are passive victims of others.
The workshop participants expressed concern at one aspect of the methodology initially
considered by the EPA Ecological Risk Workgroup. In particular, a draft report was
provided to the workshop concerning an attempt to classify ecosystems with respect to their
"inertia", "elasticity", and "resiliency". Two major difficulties occur with the approach as
presented by EPA: a) The definitions given for these concepts, as measures of ecological
response to stress, do not reflect the terms or concepts commonly in use in stress ecology;
consequently, considerable confusion results from the assignment of values for each term
for each ecosystem type; b) Ecosystems cannot be categorized for their stress-response
characteristics independently from consideration of specific stresses. This follows for
several ecological reasons, including the nature of the stress regime under which a
particular ecosystem type has developed over evolutionary times. For example, a tropical
rain forest is very capable of accommodating the ecological perturbation of a species
introduction, because the ecological community structure is so complex; on the other hand,
the tropical rain forest is very vulnerable to effects of clear-cutting or fires, because so
much of the bioavailable nutrients are in living biomass and so little is stored in soil
systems; by contrast, a grassland is well adapted to occurrences of fires at particular
frequencies, but very sensitive to introduction of an over-grazing species. Many other
ecological examples could be illustrated. Consequently, the EPA group's efforts to classify
ecosystem types as being very vulnerable, moderately vulnerable, or not very vulnerable,
and to assign ecosystem types to a plot of elasticity versus resiliency, without specifying
the nature of the stress, are ecologically inappropriate. The ecological effects workshop
was informed that this approach had been abandoned by EPA; we here wish to reiterate the
need to do so.
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The workshop participants did not evaluate in detail the initial rankings performed by the
EPA Ecological Risk Workgroup. However, there is concern among the ecological experts
that too great an emphasis was given to certain locally important issues, especially potential
ecological effects from mining operations, at the expense of insufficient emphasis on
larger-scale issues, such as climate alteration and UV-B enhancement. Concern was also
expressed about the intent to collapse the EPA ranking matrix to a single value assigned for
each environmental problem area. The problems discussed above suggested to the
workshop participants that the initial EPA rankings for each cell in the matrix require much
more explicit consideration of issues of the scale of inputs, scale of effects, qualitative
nature of effects, and relative contributions from each problem area, in order for the
rankings to be sufficiently defensible. Adding the effect of aggregation of the rows and
columns of the matrix into a single prioritization for the listed environmental problem areas
considerably exacerbates the lack of defensibility and reproducibility of results.
The final comment from the workshop participants concerns important environmental
issues for which EPA has little or no role in management and protection. The workshop,
in its preparation of the list of priorities for ecological stresses (Table 6), recognized three
broad categories of primary concern: a) anthropogenic disturbances to the global
atmosphere (e.g., greenhouse and ozone-depleting gases); b) anthropogenic inputs of toxic
organic and inorganic chemicals; and c) physical alteration of habitats of ecosystems. It is
the third category that has the least activity by EPA, primarily for reasons of maintaining
land use and water resource management functions at the state level, following a long-
standing legal policy in the U.S. and as explicitly directed by the statements of purpose of
the Clean Water Act, the Clean Air Act, etc. However, the workshop participants were
asked not to restrict their deliberations to EPA-managed or regulated environmental
problems. Further, it was clear, from the presentations of the potential ecological impacts
from habitat destruction associated with mining operations and with a variety of sources of
physical disruption to coastal and wetland systems, that EPA recognizes the potential for
very significant and long-lived adverse ecological consequences from physical habitat
disturbances; yet, the area of land subject to disruptions from mining alterations is small
compared to the area of terrestrial, wetland, and aquatic systems subject to severe habitat
alteration through conversion to agricultural uses, urbanization, highway construction,
channelization, damming, and similar activities.
The ecological effects workshop was not charged with recommending legislative
amendments or initiatives to effect specific new regulatory functions by EPA. However,
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from an ecological perspective, we can state that, if special ecological concern is recognized
for the potential effects of habitat alteration, which is appropriate to do, then it needs to be
put into the context of the full range of human activities, not just that subset of activities that
currently are under purview of EPA. If the goal is to advance the quality of the national
environment through regulation and management of human activities, then one of the most
important stresses to regulate is direct alteration of habitat, and this stress is intimately
linked to land-use policies.
We believe an ecological basis for evaluating specific ecosystems' responses to specific
stresses is provided by the deliberations of the ecological effects workshop. But fully
incorporating these inputs into an overall environmental risk assessment could not be done
in the time allocated for the exercise thus far. It is the consensus of the workshop
participants that a continuing effort would very likely be successful in advancing the
scientific basis for ecological risk assessment based on the framework developed at the
workshop. Such a continuation project should involve: a) development of an improved
methodology for assessing potential ecological effects from stress, rather than relying on an
ad hoc methodology rushed together in a two-day workshop; b) considerable attention to
relating the anthropogenic source terms to the variety of ecological stresses experienced by
the environment; c) examination of specific ecological effects from case studies through a
concerted cross-ecosystems analysis of stress-responses; and d) continued involvement of
the same set of ecological experts, convened periodically to improve the ecological effects
evaluations as new information and methodologies become available.
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Table 4
ERG Workshop - Ecological Effects Matrix
Note: The ecological effects matrix represents the consensus of the workshop participants
concerning the potential ecological effects from the various stresses listed. Actual effects
experienced by ecosystems would depend on the nature, intensity, duration, and frequency
of the stress as applied to each ecosystem. The stress agents listed were selected to
represent the full range of ecological stresses that could exist among the EPA thirty-one
environmental problem areas. A separate matrix relating the two lists has been prepared
(Table 5), but the relative contribution of a particular stress agent from a particular
environmental problem area was not addressed by the workshop group. Thus, the group
considered the potential ecological effects from toxic organic chemicals transported through
surface water systems, as an example, but that same stress could result from industrial
effluents, non-point source run-off into streams, municipal or industrial active waste sites,
Superfund sites, accidental spills, or other sources.
The ecological effects matrix indicates the potential scale of effect, specifically biosphere,
regional, or local ecosystem levels, for each of the stress agents. Details of ecosystem-
level effects are then provided, using the scheme as illustrated by the following cell:
He
cen-ind
b,p,s
7
Where:
• Upper left - Intensity of ecological effect that potentially could occur from the listed stress
agent, plus an indication of the certainty of the projection.
H - High ecological effect
M - Medium ecological effect
L - Low ecological effect
• - No ecological effect expected
c - certain or probable ecological response expected
? - uncertain ecological prediction because of insufficient ecological understanding
or because of infrequent ecological response. Note: this designation does not
necessarily suggest a lack of probable effects, but often suggests an inability of
the participants to comment on the likely nature or intensity of effects
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• Upper right-Type of ecological response
b - potential effects on biotic community structure
p - potential effects on ecological processes
s - potential effects on species of particular importance to humans, specifically
economic, aesthetic, or endangered species
h - concern for the ecosystem as a potential route to humans for health-effects
stresses
• Lower left - Time to recovery of the ecosystem once the stress is removed
yr - years', 0-10 years
dec - decades', 10-100 years
cen - centuries', 100-1000 years
ind - indefinite-, > 1000 years
• Lower right - Footnote number.
20
-------
r\3
ecosystems »»
stress agents:
air sources
gaseous phytotoxicants
scale of effect
bioiphere regional ecosystem
H H
freshwater ecosystems
buffered lakes
-
unbuffered lakes
-
buffered streams
-
unbuffered streams
-
acid deposition
H H
L
dec 1
He b.p.s
dec 1
L
yr-dec 1
He b.p.s
yr-dec 1
air deposition of toxics
?
greenhouse gases
H H H
6. 7 7
L
cen 4
L
cen 4
L
cen 4
L
cen 4
He b.p.s
cen-ind 7
He b.p.s
cen-ind 7
He b.p.s
cen-ind 7
He b.p.s
cen-ind 7
ozone-depleting gases
H? H? H?
8 9
H?
9
H?
9
H?
9
H?
9
water sources
B.O.D
H
toxic organics
M H
He b.p.s
yr-dec
He b.p.s
yr-dec
He b.p.s
yr
He b.p.s
yr
He b.p.s.h
dec-cen 10
He b.p.s.h
dec-cen 10
He b.p.s.h
dec-cen 10
He b.p.s.h
dec-cen 10
pesticides, herbicides
M H
He b.p.s.h
dec-cen 10
He b.p.s.h
dec-cen 10
He b.p.s.h
dec-cen 10
He b.p.s.h
dec-cen 10
chlorination products
M H
toxic inorganics
M H
H? b.p.s
dec-cen 10
H? b.p.s
dec-cen 10
H? b.p.s
dec-cen 10
H? b.p.s
dec-cen 10
He b.p.s.h
dec-cen 12
He b.p.s.h
dec-cen 12
He b.p.s.h
dec-cen 12
He b.p.s.h
dec-cen 12
nutrients
M H
Me b.p.s
yr-dec 14
He b.p.s
yr-dec 14
Lc
yr 14
Me b.p.s
yr 14
microbes
16
h
16
h
16
h
16
h
16
turbidity
H
Lc b.p.s I 1 Lc b.p.s I I He b,p,s
yr 17 1 1 yr 17 I | yr 18
He b.p.s
yr 18
acids
H
oil and petroleum products
M H
He b.p.s
dec
He b.p.s
dec
He b.p.s
dec
He b.p.s
dec
H? b.p.s
yr-dec 23
H? b.p.s
yr-dec 23
H? b.p.s
yr-dec 23
H? b.p.s
yr-dec 23
thermal pollution
M
Me b.p.s.h
yr-dec 22
Me b.p.s.h
yr-dec 22
Me b.p.s.h
yr-dec 22
Me b.p.s.h
yr-dec 22
enlrainment and impingement) ?
? s
? s
? s
? s
-------
ro
ro
ecosystems »»
stress agents:
terrestrial sources
pesticides and herbicides
scale of effect
biosfhtrt regional ecosystem
?
24
solid matter
L
toxic organics and inorganics
1
24
freshwater ecosystems
buffered lakes
? b.p.s.h
25
28
28
microbes
?
24
other environmental problems
radionuclides
« • •
29 29, 30
habitat alteration
H H
introduced species
H H
40 40
28
h
29, 30
He b.p.s
yr-ind 31
H? b.p.s
40
biotechnology
? ? ?
42 42 42
gronndwater contamination
? ?
43 43
? b.p.s.h
42
? h
43
unbuffered lakes
? b.p.s.h
25
28
buffered streams
? b.p.s.h
25
28
28 II 28
28
h
29, 30
He b.p.s
yr-ind 31
H? b.p.s
40
? b.p.s.h
42
? h
43
28
h
29, 30
He b.p.s
yr-ind 32
H? b.p.j
40
? b.p.s.h
42
? h
43
unbuffered streams
? b.p.s.h
25
28
28
28
h
29, 30
He b.p.s
yr-ind 32
H? b.p.s
40
? b.p.s.h
42
? h
43
-------
ecosystems »»
ftress igents:
air source!
gaseous phytotoxicanti
marine and estuarine ecosystems
coastal
•
open ocean
•
estuaries
•
terrestrial ecosystems
coniferous form
He b.p.s
dec
deciduous forest
He b.p.s
dec
grassland
L
yr
deserlt semi-arid
L
dec
alpine/tundra
H? b.p.s
dec
ro
acid deposition
air deposition of toxics
greenhouse gases
ozone-depleting gases
water sources
B.O.D
toxic organics
pesticides, herbicides
chlorination products
toxic inorganics
nutrients
microbes
turbidity
acids
oil and products
thermal pollution
? s
2
?
5
He b.p.s
cen-ind 7
H?
9
L
Me b.p.s. h
dec-cen 10
Me b.p.s.h
dec-cen 10
M? b.p.s
dec-cen 10
L?
dec-cea 13
Me b.p.s
yr 14
h
16
He b.p.s
yr-dec 19
-
H? b.p.s
yr-dec 23
-
? s
2
?
5
T
H?
9
-
?
?
T
?
-
' ,'.
-
-
7
-
L s
dec 2
7
5
He b.p.s
cen-ind 7
H?
9
He b.p.s
yr-dec
He b.p.s.h
dec-cen 10
He b.p.s.h
dec-cen 10
H? b.p.s
dec-cen 10
H? b.p.s.h
dec-cen 13
He b.p.s
yr 14. 15
' ,'.
Me b.p.s
yr 20
L
21
H? b.p.s
yr-dec 23
Me b.p.s.h
yr-dec 22
He b.p.s
dec
?
4. 5
He b.p.s
cen-ind 7
H?
9
' 1
11
11
11
11
11
h
16
11
11
-
11
He b.p.s
dec
?
4. 5
He b.p.s
cen-ind 7
H?
9
1 ' '
11
11
11
" n
11
h
16
11
11
-
11
L?
yr
?
4. 5
He b.p.s
:en-ind 7
H?
9
-
11
11
11
' ,-,
11
h
16
11
' n
-
11
-
T
4. 5
He b.p.s
cen-ind 7
H?
9
-
11
11
11
' n
' „
• r.
n
- ,-,
-
n
<
L?
dec
?
4. 5
He b.p.s
:en-ind 7
H?
9
-
11
11
11
11
' „
' ,'«
11
' ,',
He b.p.s
lec-cen 23
11
lentrainment
J I
JL
-------
ecosystems »»
stress agents:
terrestrial sources
pesticides and herbicides
marine and estuarine ecosystems
coastal
? b.p.s.h
25
open ocean
-
estuaries
? b.p.s.h
25
terrestrial ecosystems
coniferous forest
? s,h
26
deciduous forest
? s,h
26
grassland
? s,h
26
desertl semi-arid
? s,h
26
alpine/tundra
? s,h
26
ro
-P*
solid matter
toxic chemicals
microbes
-
-
28
1
?
?
1
•>
-
-
28
-
-
28
other environmental problems
radionuclides
habitat alteration
h
29, 30
h
29, 30
h
29, 30
Le
vr-ind 33
-
He b.p.s
vr-ind 34
introduced species
H? b.p.s
40
41
H? b.p.s
40
biotechnology
groundwater contaminatioi
? b.p.s.h
42
? b.p.s.h
42
? b,p,s,h
42
-
-
? h
43
1 h
24
? h
24
? h
24
? h
24
? h
24
? h
24
? h
24
? h
24
h
29^ 30
h
29, 30
-
29, 30
? h
24
? h
24
h
29, 30
h
29, 30
He b,p,s
yr-ind 35
He b,p,s
yr-ind 35
He b.p.s
yr-ind 36
He b,p,s
yr-ind 37
1 He b.p.s
lyr-ind 38
H? b.p.s
40
H? b.p.s
40
? b,p,s,h
42
? b.p.s.h
42
H? b.p.s
40
H? b.p.s
40
H? b.p.s
40
1? b.p.s.h
42
? b.p.s.h
42
? b.p.s.h
42
h
44
h
44
h
44
h
44
h
44
-------
ecosystems »»
stress agents:
air sources
gaseous phytotoxicants
wetland ecosystems
freshwater - isolated
buffered
?
unbuffered
?
freshwater -flow ing
saltwater
'
ro
en
acid deposition
-
M?
dec 3
-
-
air deposition of toxics
-
-
-
-
greenhouse gases
He b,p,$
cen-ind 7
He b.p.s
cen-ind 7
He b.p.s
cen-ind 7
He b.p.s
cen-ind 7
ozone-depleting gases
H?
9
H?
9
H?
9
H?
9
water sources
B.O.D
M
yr
M
vr
M
yr
M
yr
toxic organics
He b.p.s.h
dec-cen 10
He b.p.s.h
dec-cen 10
He. b.p.s.h
dec-cen 10
He b.p.s.h
dec-cen 10
pesticides, herbicides
He b.p.s.h 1 1 He b.p.s.h 1 1 He b.p.s.h
dec-cen 10 I 1 dec-cen 10 I I dec-cen 10
He b.p.s.h
dec-cen 10
chlorination products
H? b.p.s
dec-cen 10
toxic inorganics
M?
dec-cen
H? b.p.s
dec-cen 10
H? b.p.s
dec-cen 10
H? b.p.i
dec-cen 10
M?
dec-cen
M? II MT
dec-cen 1 1 dec-cen
nutrients
Me 1 1 H? b.p.s
yr-dec 14 I I yr-dec 14
M?
yr-dec 14
Me
yr-dec 14
microbes
h
16
turbidity
L
yr
h
16
h
16
h
16
L
yr
L
yr
Me D.p.s
yr
acids
He b.p.s
dec
He b.p.s
dec
He b.p.s II -
dec II
oil a>id products
-
-
M b.p.s
dec
M b.p.s
dec
thermal pollution
Me b.p.s.h
yr-dec 22
Me b.p.s.h
yr-dec 22
Me b.p.s.h
yr-dec 22
Me b.p.s.h
yr-dec 22
[enlrainment
-
-
-
-------
ro
ecosystems »»
itrcs* agents:
terrtstrial sources
pesticides and herbicides
wetland ecosystems
freshwater - isolated
bitfered
? b.p.s.h
27
unbuffered
? b.p.s.h
27
freshwater -flowing
? b.p.s.h
27
saltwater
1 b.p.s.h
27
solid matter
28
toxic chemicals
h
28
microbes
h
28
other environmental problems
radionuclides
habitat alteration
h
29, 30
28
h
28
h
28
h
29, 30
He b.p.s
yr-ind 39
introduced species
biotechnology
H? b.p.s
40
? b.p.s.h
42
groundwater contamination
? h
43
He b.p.s
yr-ind 39
H? b.p.s
40
? b.p.s.h
42
? h
43
28
h
28
h
28
28
h
28
h 1
29. 30 1
h
28
h
29, 30
He b.p.s
yr-ind 39
H? b.p.s
40
? b.p.s.h
42
? h
43
He b.p.s
vr-ind 39
H? b.p.s
40
? b.p.s.h
42
? h
43
-------
Table 4 Footnotes:
1.) Recovery time linked to residence time, watershed source time, and biotic and sediment
memory.
2.) Potential effects on anadromous fish populations, especially on early stages in life
cycles.
3.) Potential effects on waterfowl populations resulting from effects on food resources.
4.) A primary concern is Pb from automobile exhaust; also potential ecological effects
from Hg and certain toxic organics.
5.) Currently at global level are demonstrated changes in background levels of Pb and
other metals plus detectable amounts of xenobiotic organics; effects on ecosystems
unknown.
6.) Ecological effects are certain to occur because the stress will be severe, even if all
sources of greenhouse gases are immediately eliminated; timing of effects will be
delayed.
7.) Scenario considered: 3-4'C increase globally and 25-40% reduction in precipitation;
greater effects at higher latitudes; ecological effects are certain to occur because of the
magnitude of the stress, but specific ecological responses are uncertain.
8.) EPA scenario of UV-B increase by 20% by the year 2050 because of catalytic effect of
CFCs on stratospheric ozone; more recent projections, based on ozone holes over
Antarctica and perhaps the Arctic plus new data from Switzerland suggest UV-B
increases may be more severe than this scenario.
9.) Effects from increased UV-B levels are almost certain to occur for all ecosystem types,
but specific ecological responses uncertain.
10.) Intensity and duration of ecological effect function of toxicity, persistence, fate-and-
transport, partitioning, and bioaccumulation of the chemical in the ecosystem.
11.) Effects from aerial, terrestrial, and groundwater inputs are considered separately;
thus, because of the way the sources are defined, these water sources are not stress
agents for these ecosystems.
12.) Buffered aquatic ecosystems somewhat less sensitive than unbuffered ecosystems,
but potential ecological effects still high.
13.) Metals persist in sediments, but metal toxicity tends to be less than organic toxicity,
metals may be less bioavailable, and metal bioaccumulation is less likely to occur as
the toxin is transferred through trophic chains.
14.) Responses to nutrient additions are a function of nutrient status of the ecosystem plus
the ratio of N:P in the inputs
27
-------
15.) Water residence time and the relative contribution of riverine water to the estuary are
important factors in determining ecological effects.
16.) No ecological effects from these pathogens are likely; concern is for the ecosystem as
a route for exposure to humans.
17.) Effects on aquatic ecosystems primarily result from reduced sunlight throughout the
water column.
18.) Ecological effects are primarily from smothering of benthos.
19.) Ecological effects can be very significant for coral reef ecosystems and shallow
macrophyte communities; effect on coastal ecosystems is a function of water depth,
distance from source, and current velocities.
20.) Level of ecological effect related to natural turbidity levels.
21.) Ecological effects on estuaries are very localized; acid swamp drainage in North
Carolina has shown estuarine damage.
22.) Ecological effects are highly localized, and vary with season and latitude; elevated
water temperature may enhance the spread of human pathogens.
23.) Source includes both chronic releases and accidental spills of petroleum products into
the environment. Ecological effects from chronic inputs are not well known; effects
from spills are highly variable; the type of oil spilled is important to determining
ecological effects; recovery time may vary with type and duration of exposure.
24.) Effects on ecosystems are very localized.
25.) Direct drift from agricultural applications is the only source considered; exposures to
agricultural biocides transported through atmospheric, surface water, or groundwater
systems are considered elsewhere.
26.) Ecological effects from drift are uncertain, but likely to be localized, with important
ecological effects primarily involving biocides affecting non-target organisms; also of
concern, route to humans.
27.) The primary source is for insect control.
28.) Effects from leachate are considered elsewhere, associated with water and
groundwater sources.
29.) There are no demonstrated ecological effects from routine emissions; ecological
concern is limited to route to humans.
30.) Very locally, accidental releases can result in ecologically significant doses (e.g.,
Chernobyl).
28
-------
31.) Examples of physical habitat alteration for lake ecosystems are filling and dredging,
shoreline construction, and sedimentation.
32.) Examples of physical habitat alteration for stream ecosystems are channelization,
dredging, filling, shoreline construction, changes to watersheds, and changes to the
hydrologic regime.
33.) Localized ecological effects can occur, such as from causeway construction, sand and
gravel mining, or loss of sediment load from upstream dams.
34.) Examples of physical habitat alteration for estuarine ecosystems include dredging and
filling, upstream dam construction, shoreline stabilization, and changes to the
watershed.
35.) Examples of physical habitat alteration for forest ecosystems include silviculture,
mining, conversion to agriculture, urbanization, highway construction, and flooding
from dams.
36.) Examples of physical habitat alteration for grassland ecosystems include irrigation and
conversion to agriculture, mining, urbanization, and highway construction.
37.) Examples of physical habitat alteration for arid and semi-arid ecosystems are irrigation
and conversion to agriculture, urbanization, mining, and highway construction.
38.) Examples of physical habitat alteration for alpine and tundra ecosystems are pipeline
construction, mining, oil exploration, and highway construction.
39.) Examples of physical habitat alteration for wetland ecosystems are dredging and
filling, water diversion, phosphate mining, conversion to agriculture, and
urbanization.
40.) Species introductions occur frequently, usually with little ecological consequences;
however, infrequently such introductions result in serious ecological effects;
examples include gypsy moth infestations of forests, loss of complete populations of
important tree species from chestnut blight and Dutch Elm disease, invasions of fire
ants in the Southeastern U.S., outbreaks of starling populations, overgrazing by
domestic animals, etc.
41.) Introductions into the open ocean are only a problem for continuous introductions,
such as following construction of a sea-level canal between the Atlantic and Pacific
Oceans.
42.) There is a remote likelihood of establishment in the open environment of engineered
organisms accidentally released from laboratories, but much higher probability of
successful establishment of deliberate releases of organisms designed to survive in
the environment; low probability of ecological effects of deliberate releases, but
potential for extremely significant consequences affecting natural microbial species
and critical ecosystem processes.
29
-------
43.) Ecological effects are limited to localized areas of groundwater reaching surface water
systems; even then, ecological effects are highly unlikely unless groundwater is the
major source to the aquatic system; the primary concern is route to humans.
44.) Potential route to humans is uptake of contaminated groundwater through the deep
root systems of trees, and subsequently entering food chains.
30
-------
Table 5
ERG Ecological Effects Workshop
Matrix Relating Ecological Stresses with EPA List
of Environmental Problems
The list of ecological stresses prepared by the ecological effects workshop is related in this
matrix to the potential sources for each stress from the list of environmental problem areas
prepared by EPA. The relative contribution of each source to each stress cannot be inferred
from this matrix, nor can the number of entries in a column be used to infer any comment
about the significance or magnitude of the source. The matrix is intended to assist EPA in
its next step in the evaluation process, specifically focusing on the anthropogenic source
terms to characterize much more fully the relative magnitude, spatial extent, frequency of
occurrence, and other issues concerning importance of each source. Once that source
characterization process is accomplished, the ecological effects detailed in Table 4 can be
related to the environmental problem areas identified by EPA.
31
-------
ERC Workshop x-Matrix
environmental problem areas »»
stress agents:
air sources
gaseous phytotoxicants
acid deposition
air deposition of organics and metals
greenhouse gases
ozone-depleting gases
water sources
BOD
toxic organics
pesticides, herbicides
chlorination products
toxic inorganics
nutrients
microbes
turbidity
acids
thermal pollution
entrainment and impingement
oil and petroleum products
terrestrial sources
pesticides and herbicides
solid matter - sludge, mine spoils, etc
toxic organics and inorganics
microbes
other environmental problems
rad ion u did es
habitat alteration
introduced species
biotechnology
groundwater contamination
1
•
•
•
2
•
•
•
3
*
4
5
6
•
7
•
8
•
9/10
*
•
•
•
•
•
•
•
•
•
11
•
•
•
•
•
•
12
•
•
•
•
•
•
•
•
•
13/14
•
15
16
•
•
•
17
•
•
•
18
•
•
•
19
•
•
•
NOTE: This matrix is to indicate potential sources for the ecological stress agents from among the EPA
list of 31 environmental problem areas. The magnitude of sources, relative contribution to the stresses,
and ecological importance of each environmental problem area cannot be inferred from this matrix.
co
ro
-------
ERC Workshop x-Matrix
20
•
•
•
•
•
•
•
•
•
•
21
•
•
•
•
•
•
•
•
22
•
•
•
23
•
24
•
25/27
•
•
•
26
28
•
•
•
•
•
29
•
30
31
not listed
•
•
•
•
««enviromnental problem areas
stress agents:
air sources
gaseous phytotoxicants
acid deposition
air deposition of organics and metals
greenhouse gases
ozone-depleting gases
water sources
BOD
toxic organics
pesticides, herbicides
chlorination products
toxic inorganics
nutrients
microbes
turbidity
acids
thermal pollution
entrainment and impingement
oil
terrestrial sources
pesticides and herbicides
solid matter - sludge, mine spoils, etc
toxic organics and inorganics
microbes
other environmental problems
radionuclides
habitat alteration
introduced species
biotechnology
groundwater contamination
CO
CO
-------
Table 5
Key for Modified List of Environmental Problems
1.) Criteria air pollutants from mobile and stationary sources - includes acid precipitation
2.) Hazardous/toxic air pollutants
3.) Other air pollutants - e.g., fluorides, total reduced sulfur
4.) Radon - indoor pollution only - NOT CONSIDERED BY ECOLOGICAL
WORKSHOP
5.) Indoor air pollution - other than radon - NOT CONSIDERED BY ECOLOGICAL
WORKSHOP
6.) Radiation - other than radon
7.) Substances suspected of depleting stratospheric ozone layer - e.g., chlorofluorocarbons
8.) CO2 and global warming
9 and 10.) Direct and indirect point-source discharges to surface water - e.g., industrial
sources, POTWs
11.) Non-point source discharges to surface water plus in-place toxics in sediments
12.) Contaminated sludge - includes municipal and scrubber sludges
13. and 14.) Physical alteration of aquatic habitats - e.g., dredge and fill
15.) Drinking water at the tap - including chemicals, lead from pipes, biological
contaminants, radiation, etc. - NOT CONSIDERED BY ECOLOGICAL
WORKSHOP
16.) Active hazardous waste sites - includes hazardous waste tanks; inputs to groundwater
and other media
17.) Inactive hazardous waste sites - Superfund; inputs to groundwater and other media
18.) Municipal non-hazardous waste sites - inputs to groundwater and other media
19.) Industrial non-hazardous waste sites - inputs to groundwater and other media
20.) Mining wastes - e.g., oil and gas extraction wastes
21.) Accidental releases of toxics - all media
34
-------
22.) Accidental oil spills
23.) Releases from storage tanks - includes product and petroleum tanks; aboveground and
underground
24.) Other groundwater contamination - includes septic tanks, road salt, injection wells,
etc.
25. and 27.) Pesticide residues on food eaten by humans or wildlife and other pesticide
risks - including leaching and runoff of pesticides and agricultural chemicals, air
deposition from spraying, etc.
26.) Application of pesticides - includes risk to pesticide workers as well as consumers
who apply pesticides - NOT CONSIDERED BY ECOLOGICAL WORKSHOP
28.) New toxic chemicals
29.) Biotechnology
30.) Consumer product exposure - NOT CONSIDERED BY ECOLOGICAL
WORKSHOP
31.) Worker exposure to chemicals - NOT CONSIDERED BY ECOLOGICAL
WORKSHOP
35
-------
Table 6
ERC Ecological Effects Workshop
Environmental Stresses Priorities List
The ecological effects workshop identified the potential effects on various ecosystems from
a number of stress agents. These stresses do not correspond directly to EPA's list of 31
environmental problem areas (sources), but, rather, require translation through
understanding the relative contributions of each source to each stress type. Insufficient
information was available to the workshop group to do that translation; however, the group
did identify the most important environmental stresses at the biosphere, regional, and local
scales. As in Table 4, these scales are nested; i.e, a major effect at a higher scale implies
effects also at the lower scales (e.g., a high effect on the biosphere will include potentially
high effects on regional and local scales). These priority stresses are listed here, along with
the numbers of the associated sources as listed on EPA's list. No inference can be made
concerning priorities for the EPA-listed sources, however. For example, toxic organics in
surface water systems was identified as a major concern at the local ecosystem level, but
those chemicals could have come from listed items 9,10,11,12,21,22, or 28; the relative
contribution of these sources is unknown to the workshop group.
36
-------
Scale of potential ecological effects
High ecological
importance
biosphere
• global climate changes
from greenhouse gases (8)
regional
• regionally transported
gaseous toxicants (1)
• acid deposition (1)
• habitat alteration
(13-14)
ecosystem
• locally transported
gaseous toxicants (1,2)
• toxics in surface water
(9,10,11,12,21,22,28)
• pesticides, herbicides (25)
•nutrients (9,10,11)
• acid inputs to surface waters (9,10,20)
•oil(9,10,ll,20,22)
• habitat alteration (13-14,20)
Medium
ecological
importance
oil (9,10,11,20,22)
toxics in water
(9,10,11,16,17,28)
herbicides, pesticides (27)
B.O.D. (9,10)
turbidity (11,20)
Unknown but
potentially very
important
• uv-B from ozone depletion (7) • biotechnology (29)
' groundwater contamination
(12,16,17,18,19,20,23,24)
chlorination (9,10)
-------
Appendix A
EPA Ecological Risk Workgroup Initial Ranking
The EPA Ecological Risk Workgroup prepared an initial ranking of the EPA list of
environmental problems (as modified; see Table 5) with respect to estimated ecological
effects on a set of ecosystem categories prepared by the EPA Workgroup. This matrix is
presented here. The column labeled "Initial Overall Ranking" was prepared prior to and
independently from the rest of the matrix; consequently, it is not intended to be an
aggregation across rows in the ranking matrix. The EPA ranking scheme was not
considered by the Ecological Effects Workshop when it prepared its effects matrix (Table
4).
38
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EPA Ecological Risk Workgroup Ranking
EPA
E*v
Probltm
deep
ocean
Marine A Estuarini Ecosystems
coastal estuaries tidal
wetlands
cold warm
streams streams
Freikwater Ecosystems
lakes wetlands
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
.
L
L
M
L
M
L
L
L
L
H
H
L
L
.... ....
.
M L
M
M
M
M
L M
M
U
.
H
H
H
H
L
H
U
.
H
H
H
H
L
H
V
.
U
H
H
H
L
H
U
.
U
H
H
H
L
H
U
L
U
H
H
H
L
M
U
.
U
H
H
H
M
H
L
L
L
U L
L H
L
L M
.
.
.
L
M
L
L
H
L
H
.
L
H
L
M
M
M
H
L
H
L
L
H
L
M
L
L
H
H
L
L
L
H
L
M
L
L
H
H
L
L
L
H
L
H
L
L
L
M
L
L
M
H
L
M
M
M
H
L
L
L
M
H
.
U U
L
U
L
U
M
U
M
U
U
U
.
U
CO
IO
KEY:
U
L
M
H
no effect
unknown
low
medlu m
high
(blank) not rated
-------
EPA Ecological Risk Workgroup Ranking
EPA
Enriroinntalal
Prabltm tundra
Ttrrettrial Etoiyittm*
boreal deciduous grass- deserts subalplne tropical special
forest forest land forest forest zones
• oil
Special Ftaturtt
vulnerable
species
Initial
Ovtrall
migratory Ranking
birds
1
2
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
U
L
m
u
.
u
.
_
_
.
.
_
m
L
H
H
U
u
.
u
u
.
u
H
L
„
u
.
u
.
.
»
L
.
»
L
L
L
H
.
.
_
U
H
U
U
M
L
L
L
.
U
.
.
.
L
.
,
L
L
L
H
.
.
„
U
H
U
U
L
L
.
U
.
U
.
.
.
M
.
.
L
L
L
H
.
.
.
U
H
U
U
L
L
.
L
.
U
.
.
.
.
.
_
L
L
L
H
.
.
_
U
H
U
U
M
L
L
L
.
U
.
.
.
L
.
.
L
L
L
H
.
.
.
U
H
U
U
L
L
L
U
.
U
.
.
.
L
.
.
L
L
L
H
.
.
.
U
H
U
U
.
L
.
.
U
U
u
u
u
u
u
u
L
L
L
H
L
U
.
L
H
U
U
H
L
.
L
.
U
.
.
.
L
L
L
L
H
L
.
L
L
H
.
U
L
M
.
.
.
U
H
H
H
L
L
L
L
H
L
M
.
L
H
U
U
.
M
.
.
.
U
L
L
L
-
.
.
.
H
-
M
.
.
H
U
U
H
H
H
L
L
M
H
H
H
H
H
L
M-H
M
M
H
H
M
L
M
H
M
M
KEY:
.
u
L
M
H
(blank)
no effect
unknown
low
medium
high
not rated
-------
Appendix B
ERC Workshop on Ranking of Environmental Problems
Agenda
Tuesday, 28 October 1986
0900 Convene Joint Session of Outside Expert Group plus I
Ecological Risk Workgroup
0900-0915 Objectives of Workshop -Harwell
0915 -1200 Background briefings by EPA personnel
• Overview of Comparative Risk Project
• Previous work by Ecological Risk Workgroup
• Overview of Environmental Problems List
Discussions
• Critique of previous EPA work
1200 -1330 Lunch
1330 - 1800 Discussions within Outside Expert Group
Agreement on methodology to be used
Refinement of environmental problems list
Agreement on ecosystem categories
Agreement on criteria for ecological effects
evening informal discussions to continue in small groups at and after dinner
Wednesday, 29 October 1986
0900 -1200 Continuation of discussions within Outside Expert Group
• Develop environmental stress/ecosystem effects matrix
• Assign relative ranking for environmental problems list
1200 - 1330 Lunch
1330 -1530 Continuation of discussions within Outside Expert Group
• Finalize rankings
• Discuss EPA role re most important environmental problems
1530 -1700 Joint Session of Outside Expert Group plus EPA Ecological Risk
Workgroup
• Report on consensus of Outside Expert Group
1700 Adjourn
41
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ERC Ecological Effects Workshop
Attendees
Dr. Mark A. Harwell, Ecosystems Research Center, Cornell University, Ithaca,
New York - Chairperson
Dr. Jim Detling, Natural Resource Ecology Laboratory, Colorado State
University, Ft Collins, Colorado
Dr. Katherine Ewel, Department of Forestry, University of Florida, Gainesville,
Florida
Dr. Robert Friedman, Office of Technology Assessment, U.S. Congress,
Washington, D.C.
Dr. W. Frank Harris, Division of Biotic Systems and Resources, U.S. National
Science Foundation, Washington, D.C.
Dr. Robert Howarth, Section of Ecology and Systematics and Ecosystems
Research Center, Cornell University, Ithaca, New York
Dr. John R. Kelly, Ecosystems Research Center, Cornell University, Ithaca,
New York
Dr. Michael Pilson, Marine Ecosystem Research Laboratory, University of
Rhode Island, Kingston, Rhode Island
Dr. John Schalles, Department of Biology, Creighton University, Omaha,
Nebraska
Dr. Richard Wiegert, Department of Zoology, University of Georgia, Athens,
Georgia
Ms. Roxanne Marino, Section of Ecology and Systematics and Ecosystems
Research Center, Cornell University, Ithaca, New York - rapporteur
42
-------
Appendix B
-------
Background Papers for Environmental Problems
1. Criteria air pollutants from mobile and stationary sources
— include acid precipitation
2. Hazardous/toxic air pollutants
6. Radiation - Other than radon
7. Substances suspected of depleting stratospheric ozone layer
(e.g., chlorofluorocarbons)
8. C(>2 and global warming
9/10. Direct and indirect point-source discharges to surface
waters (e.g., POTWs, industrial discharges)
11. Nonpoint-source discharges to surface water, plus in place
toxics in sediment
12. Contaminated sludge - includes municipal and scrubber
sludges
13/14. Physical alteration of aquatic habitat (e.g., dredge and
fill)
16. Active hazardous waste sites - includes hazardous waste
tanks
17. Inactive hazardous waste sites - Superfund
18. Municipal nonhazardous waste sites
19. Industrial nonhazardous waste sites
20. Mining wastes (e.g., coal, oil and gas)
21. Accidental releases of toxics - to all media
22. Accidental oil spills
23. Releases from underground storage tanks - includes product
and petroleum tanks; above ground and underground
24. Other groundwater contamination - includes septic tanks,
road salt, injection wells
-------
-2-
25/27. Pesticide residues on food eaten by humans or wildlife;
other pesticide risks - includes leaching and runoff of
agricultural chemicals, air deposition of spraying
28. New toxic chemicals
29. Biotechnology
30. Consumer product exposure - limited to ecological effects
of plastic material
-------
OAQPS: 11/86
OZONE AND ACID DEPOSITION: ECOSYSTEMS EFFECTS
I. Overview
Based on the most recent scientific assessment of ozone and Its Impacts
on forests and natural ecosystems prepared by EPA's Office of Research and
Development and reviewed and accepted by the Agency's Science Advisory
Board, significant potential and existing effects are associated with
stress due to ozone. Ozone, the most pervasive air pollution problem 1n
the United States, 1s generally considered the most phytotoxlc air pollutant
adversely affecting vegetation 1n blotlc ecosystems. Stresses placed on
biota and the ecosystems of which they are a part can produce changes that
are long lasting and that may be Irreversible. Ozone 1s the product of the
photochemical reaction of precursor pollutants, mainly volatile organic
compounds (VOC) and oxides of nitrogen (NOX). These precursors are emitted
by thousands of sources distributed across the country.
Although the available data on add deposition effects is more uncertain
than that for ozone, there 1s evidence of damage to ecological systems,
particularly aquatic systems. The acid deposition stress agents (compounds
of sulfur and nitrogen) are emitted in large quantities 1n the United States
and Canada, and can be transported for hundreds of miles. Ecosystems in
areas where the buffering capacity of soil and water 1s low are particularly
susceptible. These areas Include the upper Midwest, the Northeast,
Southeast, and some areas in the Western mountains. About 10 percent of
the lakes in these areas have pH levels less than 5.0.
Because of the very high level of emissions, the broad geographic
coverage of potential Impacts, and the significance of observed effects
(particularly for ozone), criteria air pollutants (viz. phytotojc and
acid deposition) should be ranked as having high ecological risk.
-------
n. OZONE
Sources of Stress
Photochemical production of ozone depends both on the presence of
precursors, volatile organic compounds (VOCs) and nitrogen oxides (NOX),
emitted by manmade and by natural sources; and on suitable conditions of
sunlight, temperature, and other meteorological factors. Because of the
Intervening requirement for meteorological conditions conducive to the
photochemical generation of ozone, emission Inventories are not as direct
predictors of ambient concentrations of secondary pollutants such as ozone
and other oxldants as they are for primary pollutants.
Emissions of manmade VOCs (excluding several relatively unreactive
compounds such as methane) in the United States have been estimated at
19.9 teragrams per year (Tg/yr) for 1983 (U.S. Environmental Protection
Agency, 1984). Retrospective estimates show that manmade VOC emissions
rose from about 18.5 Tg/yr 1n 1940 to about 27.1 Tg/yr 1n 1970 (U.S.
Environmental Protection Agency, 1986). An examination of trends 1n manmade
VOC emissions for 1970 through 1983 shows that the annual emission rate for
manmade VOCs decreased some 26 percent during this period. The main sources
nationwide are larger Industrial processes, which emit a wide variety of
VOCs, such as chemical solvents; moderate to small processes, such as dry
cleaning; and transportation, which Includes the emission of VOCs from
gasoline handling as well as 1n gasoline combustion products. Estimates of
blogenlc emissions of organic compounds 1n the United States are highly
Inferential but data suggest that the yearly rate 1s the same order of
magnitude as manmade emissions. Most of the blogenlc emissions actually
occur during the growing season, however, and the kinds of compounds emitted
are different from those arising from manmade sources.
-------
Effects
The responses to ozone of Individual species and subspecies of herbaceous
and woody vegetation are well documented. They include (1) injury to
foliage, (2) reductions in growth, (3) losses in yield, (4) alterations in
reproductive capacity, and (5) alterations in susceptibility to pests and
pathogens, especially "stress pathogens" (National Research Council, 1977;
U.S. Environmental Protection Agency, Criteria Documents 1978, 1986).
Evidence indicates that any impact of ozone on ecosystems will depend
on the responses to ozone of the producer community. Producer species (trees
and other green plants) are of particular importance in maintaining the
integrity of an ecosystem, since producers are the source, via photosynthesis,
of all new organic matter (energy/food) added to an ecosystem. Any significant
alterations in producers, whether induced by ozone or other stress, can
potentially affect the consumer and decomposer populations of the ecosystem,
and can set the stage for changes in community structure by influencing the
nature and direction of successional changes with possibly irreversible
consequences.
There are a substantial number of studies documenting adverse impacts
from ozone and other air pollutants on the ecosystem and its biotic components.
Tables 1 and 2, taken from the U.S. EPA 1986 ozone criteria document, summarize
a number of these studies associated with ozone damage to vegetation.
Ozone-induced effects on the growth of trees has been clearly demonstrated
in controlled studies. For example, Kress and Skelly (1982) showed the
following reductions in growth in height in seedlings exposed to ozone for
6 hr/day for 28 days: American sycamore, 9 percent (0.05 ppm 03); sweetgum,
29 percent (0.10 ppm 03); green ash, 24 percent (0.10 ppm); willow oak,
-------
19 percent (0.15 ppm 03); and sugar maple, 25 percent (0.15 ppm). Similar
results have been obtained for other tree species by other Investigators.
Exposures of trees and other producers to ozone have been shown to
reduce photosynthesis In numerous studies and to alter carbohydrate alloca-
tion, expecially the partitioning of photosynthate between roots and tops.
Krause et al. (1984) have associated growth reductions 1n ozone-exposed
seedlings with foliar leaching. All three of these effects have been
postulated as mechanisms of the reduced growth seen 1n ozone-exposed
vegetation.
Reductions 1n the growth of annual rings observed 1n ponderosa,
Jeffrey, and eastern white pine have been attributed to the exposure of
the trees to 03 over a period of 10 to 20 years. Decline and dleback of
red spruce 1n the northeastern United States and reduced growth rates of
red spruce, balsam fir, and Fraser fir 1n central West Virginia and western
Virginia also have been attributed to stresses, to which air pollution 1s
a possible contributor, that began at least 20 years ago.
Evidence for the effects of ozone on other ecosystem components
Indicates that most are Indirect, occurring chiefly as a result of the
direct effects of ozone on trees and other producers. Significant
alterations 1n producer species can change the ability of a species to
compete and thus can Influence the nature and direction of successional
changes in the ecosystem.
Treshow and Stewart (1973) conducted one of the few studies concerned
with the Impact of air pollution on native herbaceous species in natural
plant communities. The aim of the study was to determine the concentration
-------
of ozone necessary to cause foliar Injury to the most prelevant species in
some of the Intermountain grassland, oak, aspen, and conifer communities.
Seventy common plant species 1nd1genuous to those communities were fumigated
with ozone to establish sensitivity.
In the aspen community, the most dramatic example was aspen (Populus
tremuloides (Michx.) Itself. A single 2-hour exposure to 0.15 ppm ozone
caused severe symptoms on 30 percent of the foliage. Because white fir
seedlings require aspen shade for optimal juvenile growth, the authors
suggested that significant losses in aspen populations might restrict
white fir development and later forest succession; conversion to
grasslands could occur. It was apparent that in a natural community
exposed to ozone, the tolerant species would soon become the dominants.
The authors concluded that ozone must be considered a significant
environmental parameter that influences the composition, diversity, and
stability of natural plant communities and that it "may ultimately play
a major role in plant succession and dominance".
One of the most thoroughly studied ecosystems 1n the United States is
the mixed-conifer forest ecosystem in the San Bernardino Mountains of
southern California. Sensitive plant species there began showing injury in
the early 1950's, and the source of the Injury was Identified as oxidants
(ozone). In an inventory begun in 1968, Miller found that sensitive ponderosa
and Jeffrey pines were being selectively removed by oxidant air pollution.
Mortality of 8 and 10 percent was found in two respective populations of
ponderosa pine studied between 1968 and 1972. Monitoring in that period
showed ozone concentrations >0.08 ppm for ^1300 hours, with concentrations
-------
rarely decreasing below 0.05 ppm at night near the crest of the mountain
slope (Miller, 1973).
In a subsequent interdisciplinary study (1973 through 1978), biotic
and abiotic components and ecosystem processes were examined.. The eco-
system components most directly affected were various tree species, the
fungal micro-flora of needles, and foliose lichens on the bark of trees.
Foliar injury on sensitive ponderosa and Jeffrey pine was observed when
the 24-hr average ozone concentrations were 0.05 to 0.06 ppm., Injury,
decline, and death of these species were associated with the major eco-
system changes observed (Miller et al., 1982).
Changes in the energy available to trees can influence biotic
interactions, so that weakened trees are more susceptible to attack by
predators such as bark beetles and to pathogens such as root rot fungi
(Stark and Cobb, 1969). Studies show that fewer western pine beetles
were required to kill weakened trees; and stressed pines became more
susceptible to root rot fungi and showed a decrease in mycorrhizal
rootlets and their replacement by saprophytic fungi.
Studies show accelerated rates of mortality of ponderosa and Jeffrey
pine in the forest overstory, resulting from 03 injury, root rot, and pine
beetle attack. In some cases, removal by fire can change the basic
structure of the forest ecosystem by causing replacement of the dominant
conifers with self-perpetuating, fire-adapted, 03-tolerant shrub and oak
species, which are considered less beneficial than the former pine forest
and which inhibit re-establishment of conifers.
-------
The National Park Service (1985) has recently reported ozone-induced
injury to vegetation in the Santa Monica Mountains National Recreational
Area, the Sequoia and Kings Canyon National Parks, Indiana Dunes National
Lakeshore, Great Smoky Mountains National Park, and the Congaree Swamp
National Monument.
Extent of Impact
In Table 3, 1983 ozone concentrations for Standard Metropolitan
Statistical Areas (SMSAs) having populations ^1 million are given by
geographic area, demarcated according to United States Census divisions
and regions (U.S. Department of Commerce, 1982). The second-highest
concentrations among daily maximum 1-hour values measured in 1983 in the
38 SMSAs having populations of at least 1 million ranged from 0.10 ppm in
the Ft. Lauderdale, Florida; Philadelphia, Pennsylvania; and Seattle,
Washington, areas to 0.37 ppm in the Los Angeles-Long Beach, California,
area. The second-highest value among daily maximum 1-hour ozone concentra-
tions for 35 of the 38 SMSAs in Table 3 equaled or exceeded 0.12 ppm.
A pattern of concern in assessing responses to ozone in human
populations and in vegetation is the occurrence of repeated or prolonged
multiday periods when the ozone concentrations in ambient air are in the
range of those known to elicit responses. In addition, the number of days
of respite between such multiple-day periods of high ozone is of possible
consequence. Data show that repeated, consecutive-day exposures to or respites
from specified concentrations are location-specific. At a site in Dallas,
Texas, for example, daily maximum 1-hour concentrations were >_ 0.06 ppm
for 2 to 7 days in a row 37 times in a 3-year period (1979 through 1981).
-------
8
A concentration of >^ 0.18 ppm was recorded at that site on only 2 single
days, however, and no multiple-day recurrences of that concentrations
or greater were recorded over the 3-year period. At a site in Pasadena,
California, daily maximum 1-hour concentrations >_ 0.18 ppm recurred on
2 to 7 consecutive days 33 times 1n that same 3-year period (1979 through
1981) and occurred, as well, on 21 separate days. These and other data
demonstrate the occurrence in some urban areas of multiple-day potential
exposures to relatively high concentrations of ozone.
Few nonurban areas have been routinely monitored for ozone concen-
trations. Consequently, the aerometric data base for nonurban areas is
considerably less substantial than for urban areas. Data are available,
however, from two special-purpose networks, the National A1r Pollution
Background Network (NAPBN) and the Sulfate Regional Experimental network
(SURE). Data on maximum 1-hour concentrations and arithmetic mean 1-hour
concentrations reveal that maximum 1-hour concentrations at nonurban sites
classified as rural can sometimes exceed the concentrations observed at
sites classified as suburban. For example, maximum 1-hour ozone concentrations
measured in 1980 at Klsatchie National Forest (NF), Louisiana; Custer NF,
Montana; and Green Mt. NF, Vermont, were 0.105, 0.070, and 0.115 ppm,
respectively. For four nonurban (rural) sites in the SURE study, maximum
1-hour ozone concentrations were 0.106, 0.107, 0.117, and 0.153. At the
five nonurban (suburban) sites of the SURE study, maximum concentrations
were 0.077, 0.099, 0.099, 0.080, and 0.118 ppm, respectively.
Ranges of concentrations and the maximum 1-hour concentrations at some of
the NAPBN and SURE sites show the probable Influence of ozone transported
from urban areas. In one documented case, for example, a 1-hour peak ozone
-------
concentration of 0.125 ppm at a NAPBN site 1n Mark Twain National Forest,
Missouri, was measured during passage of an air mass whose trajectory was
calculated to have Included Detroit, Cincinnati, and Louisville in the
preceding hours.
The data corroborate the conclusion given 1n the 1978 criteria document
(U.S. Environmental Protection Agency, 1978) regarding urban-nonurban and
urban-suburban gradients; I.e., nonurban areas may sometimes sustain higher
peak ozone concentrations than those found 1n urban areas.
Future Trends
Recent air quality data (1982-1984) indicte that 73 urban areas have
recorded violations of the national ambient air quality standards. These
areas stretch from coast to coast and border to border. Although there 1s
limited data, 1t is reasonable to assume that ozone levels are high (in
terms of the effects discussed above) 1n extensive rural areas as well,
particularly in the eastern half of the country. Moreover, based on rough
screening models, the number of urban nonattainment areas 1s expected to
decrease slightly during the next decade and then climb again toward the
turn of the century. A comprehensive ozone attainment strategy is now under
development in the Agency aimed at arresting this predicted trend. However,
the task will be extremely difficult and costly, inasmuch as most of the
"easy" sources to control (refineries, chemical plants, automobiles, etc.)
have already been regulated.
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10
III. ACID DEPOSITION
Sources of Stress
The primary materials of concern to terrestrial and aquatic ecosystems
are compounds of sulfur and nitrogen. In soil and water systems, both
anthropogenically derived and naturally derived sulfur compounds are important;
the percentages cannot be readily established. However, biological production
of nitrogen compounds may about equal that from anthropogenic sources in many
soil and water systems. For the eastern United States, anthropogenic sources
account for at least 90 percent of the sulfur compounds found in air and at
least 80 percent of the nitrogen compounds (ammonia and its salts, and nitrogen
oxides). Table 4 lists the major sources and their emissions. Figure 1
shows the distribution of S0£ emissions by State. Emissions of S02 and NOX can
be considered to be continuous.
A source close to a sensitive region will contribute relatively larger
amounts of sulfur or nitrogen than will a source farther away. Prevailing
weather patterns exist, at least in broad terms; on the average the wind
blows more often from the Southwest to the Northeast. Hence, sources upwind
will contribute relatively more to deposition in sensitive regions than
sources downwind from them. Furthermore, sources with tall stacks will have
a somewhat greater proportion of their emissions transported long distances.
These patterns have particular importance for receptor's in the Northeast.
Sulfur enters a soil system through several pathways: mineral weathering,
precipitation, dry deposition on the soil, washout of material dry deposited
on other surfaces (the forest canopy, for instance), and the fall and
decomposition of biologicat material that has taken up sulfur either from the
soil or the air. Adsorption of most sulfate deposited on soils can continue
as long as several decades especially in the Ultisols of the Southeast. Much
-------
11
of the organically-bound sulfur in soils'has accumulated over the centuries.
By 1950 in the eastern United States sulfur compounds in the air were already
at least 80 percent anthropogenically derived; even in soils with high adsorption
of sulfate, there will be a substantial excess flow of sulfur over that to be
expected with only naturally derived inputs.
Sulfur enters aquatic systems through all the same pathways it enters
soils; in addition, water passing through soils may account for much of the
sulfur entering an aquatic system. Like the soil system, the reservior of
water and sediments can also store sulfur. Because the average residence
time for water is seldom longer than a decade, in most lakes only the sediments
provide significant sulfur storage.
The case of nitrogen compounds is in one respect simpler, because nitrogen
adsorption does not appear significant in soils. Complications arise, however,
because there are two important families of nitrogen compounds, ammonia with
its salts, and nitrogen oxides. Biological activity can affect either family
and convert between them, and nitrogen is frequently the limiting nutrient
for many ecosystems. Furthermore, the biological process of nitrogen fixation
of nitrogen gas from the air can act as another source of nitrogen compounds for
soil and aquatic systems. Deposition of nitrogen compounds from the atmosphere
(primarily anthropogenically derived in the eastern United States) dominates
biological nitrogen fixation.
Effects
Some lakes and streams have been made sufficiently acidic that their
fish populations have been lost. The earliest concerns about acid deposition
in Europe and in North America were about harmful effects on aquatic systems.
Although numerous difficulties deter obtaining reliable historical data on
aquatic chemistry, enough studies have been done at enough different locations
-------
12
to provide a clear scientific consensus. The pH or alkalinity declines
(specifically, acid neutralizing capacity, ANC) have occurred in some surface
waters over broadly distributed regions in Europe and North America; the only
plausible explanation for these changes is acid deposition from anthropogenic
sources.
Lakes with ANC less than zero and pH less than five are classified as
acidic. The results of a recent eastern lake survey indicate that the largest
estimated number of lakes with pH less than five are in the Adirondacks,
Michigan's Upper Peninsula, and Florida. Other potentially sensitive areas
contain few lakes with pH less than five. The largest estimated number of
lakes with ANC less than zero are in the same regions. The overall estimated
percentages of lakes in these regions with pH less than five are: Adirondacks,
10 percent; Michigan's Upper Peninsula, 9 percent; and Florida, 12 percent.
These percentages are smaller when expressed on a lake area basis.
Acidic deposition also might be implicated 1n recently reported regional
forest declines. Over broad areas of the eastern United States and northern
Europe substantial declines in coniferous forest growth and diebacks of forest
areas have been observed. The declines or dieback appeared approximately 25
years ago, a period of time when emissions of acid precursors Increased
substantially. A number of mechanisms have been proposed relating forest
declines to acidic deposition; however, more detailed observations attempting
to establish the connection between declines and deposition have provided
mixed evidence. Some support but also some contrary evidence exists for each
mechanism.
Extent of Impact
For acid deposition to cause adverse effects it 1s necessary both that
the environmental system of concern be sensitive to deposition and that it
-------
13
actually receive substantial amounts of deposition. Except for comparatively
small areas, 1t appears that the combination of sensitivity and high deposition
1s found primarily 1n the northeastern and southeastern United States,
especially In mountainous areas.
The environmental systems of most concern are aquatic systems—lakes and
streams—and forests. An aquatic system appears to be vulnerable to add
deposition If It can provide only a limited amount basic cations and 1f the
terrestrial system within the watershed passes sulfur and/or nitrogen compounds
through while adding only a limited amount of basic cations. High mountain
terrain, where there are steep slopes and very little soil, passes sulfur and
nitrogen compounds essentially unaltered. The same 1s true of areas where
the predominant soil type is Spodosol*—acid soils that provide limited amounts
of basic material and do not adsorb sulfate. Spodosols are the predominant
soil type over much of the northeastern United States.
Other soil types in which future effects on aquatic systems may occur
are Ultisols together with certain Inceptisols. These also do not provide
many basic cations; however, they do adsorb sulfate, thus slowing the response
of the aquatic system to increased acid deposition. These soils predominate
in the Southeast, and it is quite possible that at many locations the time
before response would be between one and several decades. Since deposition
1n the southeast probably increased one to two decades ago, these soil regions
might be the locations where new adverse effects would be seen in the
relatively near future.
*Spodosol, Ultisol and Inceptisol are soil classifications, varying 1n several
characteristics, one being natural ac1dity--Spodosols are the most add of
the three.
-------
14
Figure 2 shows the wet deposition pH contours superimposed upon the
terrain and soil regions of concern; Figure 3 shows the deposition contours
superimposed upon regions where extensive areas of low surface water alkalinity
are found (portions of the regions identified as < 200 ueq 1~1).
Diebacks and declines have been observed in high elevation conifer
forests in the Northeast; however, this may relfect more the distribution of
observations than the actual distribution of Impacted forests. Figure 4
shows the deposition contours and the distribution of high-elevation coniferous
forests. To the extent that acidic deposition were to affect forests through
changes 1n aluminum mobilization in soils, the most sensitive regions would
be those having vulnerable trees where Spodosols predominate, with future
Impacts possible in Ultisol and Inceptisol regions. To the extent that
acidic deposition directly affects foliage, the most sensitive regions would
be found where deposition is heavy and vulnerable species of trees exist.
Neither effect may prove to be Important.
Future Trends
In the absence of new efforts at regulating the emissions of acid
precursors, the best prediction appears to be that sulfur emissions will
remain relatively constant in the next decade, while nitrogen oxide emissions
will increase slightly both regionally and nationally. Total emissions of
acid precursors are unlikely to change more than 10 percent. The prediction
1s based on continuing implementation of new source performance standards which
will tend gradually to reduce emissions as new sources replace old ones, and
a moderate increase in economic activity, which will tend to increase emissions.
If emissions were to remain within 10 percent of their present values,
then deposition amounts also would, although there might be some regional
-------
15
differences as patterns of emissions change. Thus deposition would be more
likely to decline slightly in the Northeast and to increase slightly in the
Southeast judging from emissions trends in the recent past. Changes of
10 percent or less 1n average deposition are smaller than the year to year
fluctuations 1n deposition amounts and thus would not likely produce noticeable
changes In the response of either aquatic systems or forests.
The real question is whether future harm would show up as a result of
the accumulation of acidifying substances at present levels of deposition.
For the case of aquatic systems the most important storage mechanism appears
to be sulfate adsorption in soils; this would likely be important only in the
Southeast. Thus, a continuation of deposition in today's amount would not
likely change by very much the numbers of Northeastern lakes or streams
adversely affected, though some future change 1n Individual lakes or streams,
perhaps as a result of episodic fluctuations In deposition, could not be ruled
out. In the Southeast it 1s possible that more lakes and streams would be
adversely affected as the accumulation of sulfate made adsorption less of a
barrier to the passage of sulfate into the aquatic system.
Because the mechanisms, if any, through which acid deposition might harm
forests are not understood, and, 1n particular, forest response times are not
known, it is Impossible to say at present whether continued deposition would
produce any adverse effects. Since forest growing times are as long or longer
than the two decades or so that deposition has approximated Us present
values, accumulating damage would have to be considered possible.
-------
16
REFERENCES
U.S. Environmental Protection Agency. (1978) A1r quality criteria for ozone
and other photochemical oxidants. Research Triangle Park, NC: U.S.
Environmental Protection Agency, Environmental Criteria and Assessment
Office; EPA report no. EPA-600/8-78-004.
U.S. Environmental Protection Agency. (1986) A1r quality criteria for ozone
and other photochemical oxidants. Research Triangle Park, NC: U.S.
Environmental Protection Agency, Environmental Criteria and Assessment
Office; EPA report no. EPA-600/8-84-020a.F.
U.S. Environmental Protection Agency. (1986) Add Deposition Research Program,
Office of Add Deposition, Environmental Monitoring, and Quality Assurance.
Prepared by ICAIR Life Systems, Inc; Contract Number 68-02-4193.
U.S. Environmental Protection Agency. (1985) The Add Deposition
Phenomenon and Its Effects; Critical Assessment Document, Office
of Acid Deposition, Environmental Monitoring and Quality Assurance.
EPA Report no. EPA-600/8-85/001.
-------
TABLC 1. FOUAR INJURY RESPONSE OF VARIOUS HAW STECIES TO OZONE AND OZONE PLUS SULFUR DIOXIDE*
Species
*p!t
(Vance Dell*
clous)
(loperlal
Nclntesh)
(Golden
Delicious)
Crept
(Ivts)
(Delaware)
Radish
cucuaber
Soybean
•egonla
(Schwaban*
land Red)
(Wlsper Ml*
rink)
IFanttsy)
(Renaissance)
(Twra)
ret
Concentration",
pp« Exoosure
0, SO, duration
1.48 8.48 0,-4 hr/day.
1 tine
SO.-4 hr/day.
1 tine
8.48 8.48 8,-4 hr/day.
1 tlM
SO,-4 hr/day
8. IS 8.U 9ft hr/day.
Sdays
SO,-4 hr/day.
S days
8. 29 8.50 0,-4 hr/day
every i days,
4 tines
SO,-4 hr/day
every C days
8.13 8.48 8,-4 hr,
1 tine
SO,-4 hr,
1 tine
Response Foliar Injury, X
Foliar
Injury
Foliar
Injury
Foliar
Injury
Foliar
Injury
Foliar
s
30
27
27
1
13
27
10
54
2S
2
IS
8
0
"*'
9
19
10
1
1
9
9
2
1
•
8
8
0
**jr*
22
19
47
4
30
S4
8
S7
S8
13
18
12
32
Interaction' Monitoring
affect Mthod*
-f
•17
•27
2
2
li
18
•18
11
32
11
3
4
32
8,-Mest
Mter
SOfNot
given
O.-Nast Mter
S0.-Hot
given
0, -UV
Deslbl
S0.-Conduc-
tlvlty
0,-ChenllMl-
nescence
S0,-F1aw
pnotonetry
OrChMllua)!-
nescence
S0,-Therw
electron
(SO,)
Calibration Funlgatlon
Mthod facility
II Controlled
cheaters
NrMatlon
tutes
Kl Controlled^
*9WtW%fMI WWf^WWfl%
tubes chanters
Nat given Exposure
chanters
Not given In envlratr
Mntally
controlled
roon
Nanltor CSTR In
Labs greenhouse
Calibrator
Rl rie»1g1as
chanter
Gas-phase
tltratlon
Reference
Sherti tt al.
(1900a)
Sherti at al.
(19BOb)
0vC Rwv vOM OTJ8JI
Hofstra
(1979)
Relnert end
Melton
(1980)
Olsiyk and
Tlbblts
(1981)
Nhere cotuan entry Is blank. Inforvatlon Is the sine as above.
Concentrations of each gas were the sane Mhen glvm together as when given singly.
cfhe "Interaction effect" Is the effect fro* the coobtnatlon of 0, and SO, •Inus the Individual effects of 0, and SO,
-------
TABU 1. GROWTH RESPONSE OF VMIOUS PLANT SPECIES TO OZONE M0 OZONE PLUS SULFUR DIOXIDE
oo
Species
Radish
(Cherry
Belle)
Alfalfa
(Vernal)
Soybean
(6are)
dVyDViam
(Dare)
Tobacco
(Oe1-W»)
Concentration*,
ppe) Exoosurt
o, so, duration
0.05 0.05 1 hr/day,
5 days/wk,
5 wks
0.05 0.05 0 hr/day,
5 days/wk
12 wk
0.05 0.05 7 hr/day,
5 days/wk
3 wk
0.10 1.10 7 hr/day,
5 days/wk,
until harvest
0.05 0.05 7 hr/day.
5 days/wk,
4 wk
Yield. X reduction
fro* control
(negative unless
Response otherwise noted)
Top dry wt
Root dry wt
Tap dry wt
Root dry wt
Top fresh wt
Root fresh wt
Top fresh wt
Seedwt
Leaf dry wt
ft
50
12
22
2
3
85
54
1
«*'
17
26
29
*5
0
•3
4
14
55
18
24
12
24
52
13
30
Interaction" Monitoring
effect Method
0
-12
-20
-27
15
21
-10
5
15
0,-Nast
•eter
S0,-Conduc-
tfvtty
0,-Nast
•eter
S0.-Conduc-
tivlty
0,-Mast
•eter
S0,-Conduc-
tivlty
0,-Nast
•eter
SO.-FlaM
pnoloaetry
0,-Nast
•eter
S0.-Conduc-
tlvlty
Calibration
•ethod
Rl
CeltH-
•etrlc
Rl
Colerl-
•etrlc
II
Color!-
•etrlc
Rl
Nat given
Rl
Colorl-
•etric
Fuaigation
facility
Chaabers
In green-
house
Chaabers
in green-
house
Chaabers
In yi een*
house
Field
chaaben
Chaabers
la* «aenaia»i»
in tji evil
house
Reference
Tlngev
et al.
(1971a)
Tlnoey and
Re inert
(1975)
Tlnoey
et al.
(1973c)
Heagle
et al.
(1974)
Tlnoey and
Re Inert
(1975)
Concentrations of each gas were the sane when given together as
*Tht •interaction affect* Is the effect fraa the coablnatlon of 0,
given singly.
I SO, •Inns tht Individual tf facts tf 0, and SO,
-------
rJ
"ts
is
J
I*
I-
II
t?l
a
»
a
k
!
c
•-« k I
<-> • I
•8 ee»
e *-H
IIS
fc?
A **
lift
n f II *
£= i *= *
5 R
is c at
s ass *
a * 5
a a
s a
i i t
z c sz
it
5s
i.
o
«
at 9t at at it
C JC
822 aaa
a&s SRR c
$
•II
\ I 4« 7 I 8S? L ..^
!?! |I I ; gg? :* -.-
gzfe « fc I SSs 5s §&i
i f
4 £
i j
8 -
| J
111
ii!
Hi
19
-------
TABLE 2 EFFECTS OF LONG-TERN, CONTROLLEO EXPOSURES ON GROWTH, YIELD
AND FOLIAR INJURY IN SELECTED PLANTS*
Plant species
Ozone
concentration,
(PP»)
Exposure tlM
Plant response, % reduction
froa control
Lesvta, duckweed
Carnation
Geranium
Petunia
Polnsettta
Radish
Beet, garden
Bean, cultlvar
Pinto
Bean, cultlvar
Pinto
Bean, cultlvar
Pinto
Bean, cultlvar
Pinto
196 (0.10)
98-177 (0.05-0.09)
137-196 (0.07-0.10)
98-137 (0.05-0.07)
196-23S (0.10-0.12)
98 (0.05)
98 (0.05)
392 (0.20)
255 (0.13)
290 (0.15)
490 (0.25)
686 (0.35)
290 (0.15)
290 (0.15)
290 (0.15)
290 (0.15)
440 (0.225)
440 (0.225)
588 (0.30)
5/day, 14 days
24/day, 90 days
9.5/day, 90 days
24/day. 53 days
6/day, 5 days/week,
10 weeks
8/day, 5 days/week,
5 weeks
8/day, 5 days/week
(•Ixture of Oj and S0t
for saae periods)
3/day, 38 days
8/day, 28 days
2/day, 63 days
2/day, 63 days
2/day, 63 days
2/day, 14 days
3/day, 14 days
4/day, 14 days
6/day, 14 days
2/day, 14 days
4/day, 14 days
I/day, 14 days
100, flowering; 36, flowering
(1 wk after exposure completed)
50, frond doubling rate
50, flowering (reduced vegetative
growth)
50, flowering (shorter flower
lasting t1«e, reduced vegetative
growth)
30, flower fresh wt
39, bract size
54, root fresh wt
20, leaf fresh wt
63, root fresh wt
22, leaf fresh wt
SO, top dry wt
79. top fresh wt
73, root fresh wt
70, height
33. plant wt; 46, pod fresh wt
95, plant dry wt; 99, pod fresh wt
97, plant dry wt; 100, pod fresh wt
8, leaf dry wt
8, leaf dry wt
23, leaf dry wt (data available on
whole plants, roots, leaves, Injury,
and three levels of soil snlsture
stress)
49, leaf dry wt
44. leaf dry wt
68. leaf dry wt (data available on
whole plants, roots, leaves, Injury,
and three levels of soil Moisture
stress)
40, leaf dry wt
-------
TABLE 2. (cont'd).
EFFECTS OF LONG-TERN. CONTROLLED OZONE EXPOSURES ON GROWTH, YIELD
AND FOLIAR INJURY IN SELECTED PLANTS*
N>
Plant species
ToMto
Com, sweet,
cultlvar Golden
Jubilee
Wheat, cultlvar
Arthur 71
SOyDvMI
Soybean
Alfalfa
Grass broM
Alfalfa**
•
A1fa1fab
Alfalfa
Pint, eastern
white
Ozone
concentration,
ug/M3 (DDK)
588 (0.30)
392 (0.20)
686 (0.35)
392 (0.20)
686 (0.35)
392 (0.20)
98 (0.05)
196 (0.10)
196 (0.10)
290 (0.15)
390 (0.20)
290-647
(0.15-0.33)(var1ed)
196 (0.10)
98 (0.05)
98 (0.05)
196 (0.10)
Exposure t1*e
3/day, 14 days
2.5/day, 3 days/week
14 weeks
2.5/day, 3 days/week.
14 weeks
3/day, 3 days/week
till harvest
3/day, 3 days/week
till harvest
4/day, 7 days
(anthesls)
8/day, 5 days/week
3 weeks
8/day, 5 days/week
(Mixture of Os and SOj
for saMe periods)
8/day, 5 days/week
3 weeks
2/day, 21 days
2/day, 21 days
2 day, 21 days
4/day, 5 days/week
growing season
6/day, 70 days
7/day, 68 days
8/day, 5 days/week
12 weeks
4/day, 5 days/week
4 weeks (Mixture of Os
and S0f for same periods)
Plant response, X reduction
f roM control
76, leaf dry wt
1, yield; 32 top dry wt; 11,
root dry wt
45, yield; 72, top dry wt; 59.
root dry wt
13, kernel dry wt; 20, top dry wt;
24, root dry wt
20, kernel dry wt; 48, top dry wt;
54, root dry wt
30, yield
13, foliar Injury
16, foliar Injury
20, root dry wt
21, top dry wt
9, root dry wt
16, top dry wt
26, top dry wt
39, top dry wt
83, bloawss
4, top dry wt, harvest 1
20, top dry wt, harvest 2
50, top dry wt, harvest 3
30, top dry wt, harvest 1
50, top dry wt, harvest 2
18, top dry wt
3, needle Mottle
(over 2-3 days of exposure)
16, needle Mottle
-------
TABLE 2. (cont'd). EFFECTS OF LONG-TERM. CONTROLLED OZONE EXPOSURES ON GROWTH, YIELD
AND FOLIAR INJURY IN SELECTED PLANTS*
ts>
Plant species
Pine, ponderosa
Pine, ponderosa
Poplar, yellow
Maple, silver
Ash, white
Sycamore
Maple, sugar
vOtft 9
cultlvar Golden
M1dgetc
Pine, ponderosa''
P1ne, western
white6
Soybean, cultlvar
Dareb
Poplar, hybrid
Ozone
concentration,
(ppM)
Exposure tine
Plant response, % reduction
from control
290 (0.15)
290 (0.15)
290 (0.15)
290 (0.15)
588 (0.30)
588 (0.30)
588 (0.30)
880-588 (0.30)
588-880 (0.45)
588 (0.30)
588 (0.30)
588 (0.30)
588 (0.30)
98 (0.05)
196 (0.10)
196 (0.10)
196 (0.10)
98 (0.05)
196 (0.10)
290 (0.15)
9/day, 10 days
9/day, 20 days
9/day, 30 days
9/day, 60 days
9/day, 10 days
9/day, 20 days
9/day, 30 days
9/day, 30 days
9/day, 30 days
13 weeks
8/day, 5 days/week
13 weeks
8/day, 5 days/week
13 weeks
8/day, 5 days/week
13 weeks
8/day, 5 days/week
13 weeks
6/day, 64 days
6/day, 64 days
6/day, 126 days
6/day, 126 days
6/day, 133 days
6/dsy, 133 days
B/day, 5 days/week
6 weeks
4, photosynthesis
25, photosynthesis
25, photosynthesis
34, photosynthesis
12, photosynthesis
50, photosynthesis
72, photosynthesis
85, photosynthesis
82, leaf drop; 0, height
SO, leaf drop; 78, height
66, leaf drop; 0, height
0, leaf drop; 22, height
28, leaf drop; 64, height
9, kernel dry wt; 14, Injury
(12, avg. 4 yield responses)
45, 25. 35 for saaw responses
12, root length
21, stem dry wt; 26, root dry wt
13, foliage dry wt
9, stew dry wt
3, seed yield; 22, plant fresh wtt;
19, Injury, defoliation, no reduc-
tion In growth or yield
55, 65. 37 for same responses
50, shoot dry wt; 56, leaf dry wt; ;
47, root dry wt
•Modified from National Research Council (1977); cited In U.S. Environmental Protection Agency (1978).
Studies conducted under field conditions, except that plants were enclosed to ensure controlled pollutant doses.
Plants grown under conditions waking then More sensitive.
-------
TABLE 3. SECOND-HIGHEST OZONE CONCENTRATIONS AMONG DAILY MAXIMUM 1-hr
VALUES IN 1983 IN STANDARD METROPOLITAN STATISTICAL AREAS WITH POPULATIONS
> 1 MILLION, GIVEN BY CENSUS DIVISIONS AND REGIONS8
Division
and region
SMSA
SMSA
population,
Millions
Second-highest
1983 03
concn, , ppm
Northeast
New England
Boston, MA
Middle Atlantic Buffalo, NY
Nassau-Suffolk, NY
Newark, NJ
New York, NY/NJ
Philadelphia, PA/NJ
Pittsburgh, PA
South
South Atlantic
South
West South
Central
North Central
East North
Central
West North
Central
Atlanta, GA
Baltimore, MD
Ft. Lauderdale-Hollywood, FL
Miami, FL
Tampa-St. Petersburg, FL
Washington, DC/MD/VA
Dallas-Ft. Worth, TX
Houston, TX
New Orleans, LA
San Antonio, TX
Chicago, IL
Detroit, MI
Cleveland, OH
Cincinnati, OH/KY/IN
Milwaukee, WI
Indianapolis, IN
Columbus, OH
St. Louis. MO/IL
Minneapolis-St. Paul, MN/WI
Kansas City, MO/KS
>2
1 to <2
>2
1 to <2
>2
>2
>2
>2
>2
1 to <2
1 to <2
1 to <2
>2
>2
>2
1 to <2
1 to <2
>2
>2
1 to <2
1 to <2
1 to <2
1 to <2
1 to <2
>2
>2
1 to <2
0.18
0.12
0.17
0.25
0.19
0.10
0.14
0.17
0.19
0.10
0.12
0.14
0.17
0.16
0.28
0.12
0.12
0.17
0.17
0.15
0.15
0.18
0.14
0.12
0.18
0.13
0.13
-------
TABLE 3. (cont'd). SECOND-HIGHEST OZONE CONCENTRATIONS AMONG DAILY MAXIMUM
1-hr VALUES IN 1983 IN STANDARD METROPOLITAN STATISTICAL AREAS
WITH > 1 MILLION, GIVEN BY CENSUS DIVISIONS AND REGIONS3
Division
and region
West
Mountain
Pacific
SMSA
Denver-Boulder, CO
Phoenix, AZ
Los Angeles-Long Beach, CA
San Francisco-Oakland, CA
Anaheim-Santa Ana-
Garden Grove, CA
San Diego, CA
Seattle-Everett, WA
Riverside-San Bernardino-
Ontario, CA
San Jose, CA
Portland, OR/WA
Sacramento, CA
SMSA Second- highest
population, 1983 03
•11 lions concn. , ppm
1 to <2
1 to <2
>2
>2
1 to <2
1 to <2
1 to <2
1 to <2
1 to <2
1 to <2
1 to <2
0.14
0.16
0.37
0.17
0.28
0.20
0.10
0.34
0.16
0.12
0.15
Standard Metropolitan Statistical Areas and geographic divisions and regions
as defined by Statistical Abstract of the United States (U.S. Department of
Commerce, 1982).
-------
TABLE 4, NATIONAL U.S. CURRENT AND PROJECTED S02 AND NOX
EMISSIONS (Tg yr-l)»
Current
1980
1.
2.
3.
4.
5.
6.
Source category
Electric utilities
Industrial boilers and
process heaters
Nonferrous smelters
Residential /commercial
Other industrial
processes
Transportation
TOTALS
S02
15.0
2.4
1.4
0.8
2.9
0.8
24.1
NOX
5.6
3.5
0.7
0.7
8.5
19.0
Projected
1990
S02 NOX
15.9 7.2
3.4 3.0
0.5
1.0 0.7
1.2 0.8
0.8 7.8
22.8 19.5
Projected
2000
S02
16.2
6.5
0.5
0.9
1.5
1.0
26.6
NOx
8.7
4.0
0.6
1.1
9.7
24.1
aSummarized from U.S./Canada Work Group 3B Draft Report (1982).
25
-------
50 x 106 kgyr"1
>50 s 250 x 106 kgyr"1
> 250 s 1000 x 106 kg yr*1
> 1000 x 106 kg yr"1
Figure 1. Annual 1980 emissions of S0£ by state. Data are from
Toothman et al. (1964).
26
-------
Spodosols
Ultisols
Inceptisols
Select Alflsols
A] Mountainous Regions
Figure 2. pH contour lines and soil regions of concern in the
United States.
27
-------
<200 peq JT1
200 - 399 Meq A'1
400 - 599 peq r1
Figure 3. pH contour lines and low alkalinity surface waters
in the United States.
-------
»*
Figure 4. pH contour lines and high-elevation forests in
the United States.
29
-------
DRAFT
11-24-86
TOXIC AIR POLLUTANTS:
A PRELIMINARY ASSESSMENT OF ECOLOGICAL RISKS
I. OVERVIEW
Definition. Toxic air pollutants can be defined generally as virtually
any substance released into the air media that may pose unreasonable risk
to human health and the environment. By such a broad definition, toxic
air pollutants include air quality criteria pollutants (i.e., sulfer
oxides, ozone, particulate matter, carbon monoxide, nitrogem oxides, and
lead) that are separately regulated under the Clean Air Act. For this
analysis, criteria air pollutants from mobile and stationary sources,
acid precipitation, are excluded from this analysis, because they are
addressed as a separate environmental problem area*. Additionally,
indoor air pollution, although a major concern in terms of human health
risks, is not addressed in this paper because it does not appear to pose
significant risks to ecosystems.
Background. A significant problem in assessing ecologcal risks is
that the air toxics problem has been defined within the Agency in terms of
potential human health problems2. The Congress, EPA and the public have
focused almost exclusively on human health concerns, as evidenced by the
increased recent attention to accidental releases^ and indoor air quality4.
Ecological effects are usually not considered or only given perfunctory
mention.
The diversity and large number of toxic air pollutants, together
with a lack of information and understanding of sources, ecosystem exposure
patterns and ecological responses, preclude a reliable assessment of the
nature and magnitude of the ecological risks. This paper presents an
overview of available information that relates toxic air pollutants to
ecological risks, but the great scientific uncertainties must be emphasized.
The findings should be considered with caution, because our understanding
of this issue will certainly change as available information grows.
1 Note: There is an overlap between criteria pollutants and toxic air
pollutants. For example, control programs designed to reduce criteria
pollutant emissions probably achieve considerable reduction is toxic
air pollutants. Also, some toxic air pollutants contribute to criteria
pollutant loadings (e.g., VOCs that are ozone precursors).
2 EPA Air Toxics Strategic Planning Initiative: Problem Assessment and Goal
Options Summary, July 1986; June 11, 1985 Statement on Air Toxics by
Lee Thomas before the House Committee on Energy and Commerce, Subcommittee
on Health and the Environment; EPA Air Toxics Strategy Document.
^ For example, Title III of the Superfund Amendments and Reauthorization
Act (SARA) gives EPA authority relating to emergency planning, emergency
notification, community right-to-know reporting of chemicals, and
emission inventory.
4 For example, SARA authorizes a research program on radon gas and indoor
air quality that will include characterization of sources, human health
effects, and control technology.
-------
-2-
II. DESCRIPTION OF SOURCES, RELEASES, CONTROLS AND EXPOSURES
The diversity and complexity of toxic air pollutant sources and
releases is apparent fron the the following categorization scheme:
Total Toxic Air Pollutant Endsions
Conventional Releases
Short-Term Releases
Routine Releases
Accidental Releases
Process
Emissions
Fugitive
Emissions
Intermittent
(Expected,
Limited,
Scheduled)
o Startup
o Shutdown
o Mainte-
nance
Intermittent
(Expected,
Limited,
Not Scheduled)
o Transient
o Upset
'Catastrophic
(Unexpected
Major Failure,
Not Scheduled)
o Processes or
Controls Fail
o Uncontrollable*
o Controllable**
* e.g., Explosion of a storage tank
** e.g., Tank ruptures and released toxicants are torched (burned off)
Routine releases are defined as those emissions to ambient air
that occur as part of the usual or expected operations of human activities,
such as the normal operation of an industrial process. Some of the most
pervasive sources of routine releases are stationary and mobile combustion
sources found throughout the country, but are concentrated in urban areas.
Accidental releases are those discharges that come from unplanned and
unexpected discharges to ambient air, such as a storage tank rupture,
process upset, or transportation accident.
Accidental releases tend to cause acute exposures. Routine releases
may involve both acute and chronic exposures, depending on the quantity
and duration of the material released and its toxicity.
Sources and Releases. The sources of toxic air pollutants are widely
varied and include traditional air pollutant sources such as emissions
from chemical plants, motor vehicles and metallurgical processes, as well
as nontraditional sources such as sewage treatment plants. A detailed
description of total toxic air pollutant emissions is not is not available.
Further, the existing lists of toxic air pollutants are based on human
health concerns and, although a large number of these compounds may also
pose ecological risks, a list prepared for ecosystem protection would be
somewhat different.
-------
-3-
In the absence of a list of toxic air pollutant sources, some examples
of kinds of sources roust suffice for source characterization:
o Petroleum handling, including over one million underground storage
tanks (UST) that store petroleum, and 50,000 USTs that store chemicals
— unknown quantity of VOCs released.
o 165,000 industrial boilers and over one million furnaces and boilers
that heat buildings — 500 million gallons of used oil is recycled
as fuel each year; used oil typically contains elevated levels of
toxic metals such as arsenic, cadmium, and chromium, and organics such as
BaP and PCBs, which are released to the air.
o 15,000 drycleaners
o 50,000 vapor degreasers that use solvents
o 175,000 coimercial pesticide appliers and about one million private
certified pesticide applicators (fanners)
o Wastewater treatment — 15,000 municipal and 20,000 industrial
o Superfund sites — 109 sites have been placed on the NPL due to high
air sources (43 for particulate, heavy metal, or radium releases; and
67 for VOC emissions).
o Municipal landfills — speculation that emissions may be high in seme
cases due to decomposing plastics, discarded solvents, and mobilization
of VDCs to the atmosphere by methane gas.
o Municipal waste incinerators — preliminary estimates of high emissions of
metals and organic compounds at poorly run facilities.
o Drinking water treatment plants — aeration is used to remove VDCs
from water.
o Coal-fired electric power plants — estimated annual release of
polycyclic aromatic hydrocarbons (PAH's) of 46,000 metric tons.
o RCRA treatment storage and disposal facilities that handle hazardous
wastes — the emission sources for VDCs and particulate matter are
numerous, including tanks, impoundments, waste piles, landfills, land
treatment operations, equipment leaks, spills, drum storage, process
vents, etc. These sources emit an estimated 3 million metric tons of
VOCs annually.
In summary, a wide variety of toxic air pollutant sources may contribute
to ecological risk. These include, but are not limited to: road vehicles;
combustion of coal and oil, woodstoves; metallurgical industries; chemical
production and manufacturing; gasoline marketing; solvent useage, and
waste oil disposal. The relative importance of each is not known. Both
point sources (major industrial sources) and area sources (smaller sources
that may be wide spread accross a given area, such as solvent useage,
motor vehicles, woodstoves) are likely contributors.
-------
-4-
Stress Agents. The principal stress agents for ecological effects
have not been identified. An EPA study of human cancer risks from air
toxics5 concluded that the following pollutants may be important contributors
to aggregrate cancer incidence from air toxics: metals, asbestos, products
of incomplete combustion6, formaldehyde, benzene, ethylene oxide, gasoline
vapors, and chlorinated organic compounds. Persistent compounds such as
metals, PCBs and TCDD may be special importance ecologically because of
foodchain effects.
Not surprisingly, trying to crosswalk specific stress agents and
sources is extrardinarily complex. The source breakdown for several
pollutants is provided below as an illustration:
Pollutant Sources
Arsenic Combustion sources such as waste oil burning, coal-fired
utility boilers, wood smoke, smelters, glass manufacturing
Benzene Road vehicles, gasoline marketing, pertoleum refining
Chloroform Solvent usage, water treatment
Chromium Waste oil burning, steel manufacturing, refractory
manufacturing, metals manufacturing, combustion
PICs Burning of wood and coal in small combustion units,
coke operations, internal combustion engine
In terms of the "stress agents" identified by the Cornell Ecosystem
Research Center, toxic air pollutants were identified as "air deposition
of toxics." The Cornell panel of of experts defined this category to
include aerial transport of metals and VOCs, such as PAHs and PCBs, and
felt that is particularly important near urban areas due to automobile
exhaust, fossil fuel combustion, and other urban sources. However, the
Cornell panel may not have been aware of the full magnitude and nature of
sources of toxic air pollutants.
Ecosystem Exposure. Ecosystem exposure to toxic air pollutants
range from catastrophic industrial accidents (e.g., Union Carbide in
Bnopal, India) to the more routine release of chemicals into the atmosphere
as part of the normal operation of countless human activities. Accidental
releases have emerged as a major issue in terms of protecting human health,
5 EPA. The Air Toxic Problem in the United States: An Analysis of Cancer
Risks for Selected Pollutants (called the "Six Month Study" because of
its original intended duration), May 1986. EPA 450/1-85-001. This
study is probably the most comprehensive attempt to date to assemble
and analyse available data on air toxics, and was used extensively to
prepare this paper.
^ "Products of incomplete combustion" (PICs) refers to a large and ill-defined
group of compounds, probably consisting primarily of polynuclear organics.
-------
-5-
but has not been analysed in terms of ecological risks. In fact, a recent
EPA report7 indicates that in over 90% of the accidental releases accidents
reported in the United States between 1981 and 1985, the ecological
consequences are listed as unknown. There are some factors that decrease
the importance of chemical accident, from an ecotoxicological viewpoint
(e.g., many accidents are in-plant occurences, and unless very large will
not reach ecosystems). However, large releases and transportation accidents
may result in greater ecosystem exposure
Routine releases to ecosystems has emerged as potentially significant
at some locations. For example, atmospheric loading of toxic pollutants
to the Great Lakes appears to be a major pathway, but the details are unknown.
Exposures to point sources are most easily identified (e.g., downwind
from a smelter), but the current state of our understanding is insufficient
to adequately predict overall ecosystem exposures to Toxic air pollutants.
Ambient air quality and atmospheric deposition information is scarce,
and is generally biased toward urban areas, but high geographic variability
of toxic air pollutants is likely. Concentrations will be highest adjecent
to sources, which generally means in and near urbanized areas. However, the
transport of air toxics for long distances does occur — emissions disperse
rapidly downwind to affect areas not in the immediate vicinity of the
source.
Overall, the geographic scale of air toxic exposure on ecosystems is
not known because of the complexity of sources and pollutants, incomplete
understanding of transport processes, and the paucity of monitoring data
from natural ecosystems. Inputs.to ecosytems that are remote from
urban sources do occur, but too little is known to make generalizations.
A further complication is atmospheric transformation of toxic
precursors during transport. EPA has done a preliminary assessment8 of
chemical reactions (e.g., photooxidation) in the atmosphere that can form
toxic compounds or increase the potency of emitted pollutants (ozone is
the prime example of this phenomenon), but existing knowledge and
exposure models cannot account for toxic compounds that may be formed or
destroyed in the atmposhere.
Impacts. Ecological impacts are possible for all ecosystem types
from toxic air pollutants. A sizable body of scientific literature
exists on air pollution damage to terrestrial vegetation, due largely to
economic concerns about losses of agricultural crops and forests, and so
forth. Emphasis has been on gaseous pollutants such as photochemical
oxidants (e.g., ozone, nitrogen oxides, etc.) and sulfer dioxide. Atmos-
pheric inputs to lakes have been documented, and impacts can be expected.
However, a lack of information on both field exposures and toxicological
effects preclude a good understanding and quantification of ecological
impacts for any ecosystem types.
7 EPA 560/5-85-029
8 Production of Hazardous Pollutants through Atmospheric Transformations.
EPA office of REsearch and Development. June, 1984.
-------
The biological impacts of toxic air pollutants have been studied in some
detail through laboratory bioassays.9 Although it is not possible to
extrapolate thse laboratory results to the field effects, it appears that
the polynuclear aromatic hydrocarbons (PAHs), nitro compounds, and
halogenated compounds are potentially harmful groups. Persistent compounds
such as metals, accumulate in an ecosystem may also be considered as a
potentially harmful group.
The difficulty of assessing and predicting impacts from toxic air
pollutants is illustrated in the dieback of german forests. Over recent
years, symptoms of a new kind of damage, which includes premature tree
defoliation leading to death, has appeared in a number of tree species in
West Germany. The problem began in the 1970"s when it was restucted to
high altitudes and older trees and became more serious after 1976. It is
believed that some kind of atmospheric pollution is involved. Initially,
it was argued that accumulated effects of increased acidity of precipitation
altered soil chemistry and damaged the trees cost systems. More recently,
many doubts have been expressed about this hypothesis and ozone has been
proposed as the responsible stress agent. However, scientific opinion is
increasingly moving toward the view that there is no single, simple cause.
The ecosystem-level effect may result from complex interactions between
more than one toxic air pollutant and other environmental stresses.
Controls. Toxic compounds are emitted into the atmosphere fram many
sources that are controlled for CAA criteria pollutants. Metals and
polynuclear compounds usually are emitted as particulate matter and most
of the VOCs as ozone precursors. As such, they are regulated indirectly
under the CAA through State Implementation Plans (SIPs), New Source
Performance Standards (NSPS), and Title II for motor vehicles. Also,
there are economic reasons for private-sector control of emission for
some volatile compounds, such as solvents.
Several EPA studies10,11 have evaluated the effects of these indirect
controls on toxic air pollutants and made the following conclusions. Control
of metals from point sources is generally high, ranging from 80-98%. For
point-source emissions of organics, percentage controls range from
30-90%. To examine area sources and motor vehicles, air quality trends
rather than control regulations have been evaluated. Generally, heavy-
metal reductions of 30-70% have been observed since the 1960s. In addition,
SIPs and NSPS are credited with reducing emissions of 15 chemicals from the
the chemical industry by 10-80%, and 8 solvents by 30% nationwide. Motor
vehicle controls now remove up to 90% of some potentially toxic compounds
from exhaust gases.
9 Graedel, T.E., D.T. Hawkins and L.D. Claxton. 1986
Handbook of Atmospheric Compounds; Sources, occurrence, and Bioassay.
Acodemic Press.
10 EPA. Characterization of Available Nationwide Air Toxics Emissions Data.
Unpublished report by Tom Lahre. June, 1984.
11 PA. Estimation of Cancer Incidence Cases for Selected Toxic Air
Pollutants Using Ambient Air Pollution Data, 1970 vs. 1980. Unpublished
report by W. F. Hunt et al. April, 1985.
-------
—7—
Even from these cursory analyses, it is apparent that indirect
controls can be very significant in reducing emissions of toxic air
pollutants. At this time, controls for criteria pollutants for exceed
the impact of Section 112 regulations. Finally, since sources are already
being controlled by criteria pollutant programs, the remaining emissions
will probably be more difficult to control.
Information Availability and Quality. Major weaknesses and gaps
characterize the base of information on toxic air pollutants. The few
air toxics emission inventories that are available generally show
inconsistencies and anomalies, the air quality data that exists is
inadequate to develop ecosystem exposure estimates, and few compounds
have been tested for ecotoxicological effects. The data limitations
preclude performing any type of comprehensive assessment of ecological
risks.
-------
Figure 1. Proposed Ranking of Ecological Risks from
Toxic Air Pollutants
CM
iH
co
4J
M-l
0)
4-1
C
M
Ecosystems
Freshwater
Marine and estuarine
Terrestrial
Wetland
Buffered lakes
Unbuffered lakes
Buffered streams
Unbuffered streams
Coastal
Open ocean
Estuaries
Coniferous forest
Deciduous forest
Grassland
Desert/Semi-arid
Alpine/Tundra
Freshwater - isolated
Freshwater - flowing
Saltwater
2
r i
s
•H
81
<0 .v
•P W
L
L
L
L
?
?
?
?
?
?
?
?
M
-
—
H
M
H
H
?
?
?
?
?
?
?
?
M
M
M
M
M
L
H
M
M
M
M
L
M
M
M
M
M
M
M
?
?
?
?
?
?
?
?
—
—
-
12 The significance of ecological effects of toxic air pollutants that reach
a particular ecosystem type (? = unoerain because of insufficient
ecological understanding).
" The time required for ecosystem recovery after an impact (L = 1 year;
M = 10 years; H = 100 or more years)
14 At a national scale, the expected exposure of different ecosiystems to
toxic air pollutants
-------
Problem *6 Badioactivity - Other Than Radon
Introduction
The activities of nan have increased exposure of the
ecosystem to radiation in two vays. The first is by alteration
of the distribution of naturally occurring radioactive
material. Thus, activities such as mining, industrial
processing of raw materials, and use of contaminated products
can uncover and concentrate previously sequestered
radioactivity. The second is through applications -of nuclear
technology which produce radioactive material. Thus, nuclear
reactors and particle accelerators can increase the abundance of
radioisotopes in the ecosystem or create radioisotopes which did
not previously exist.
I. Sources. Releases, and Responses
The sources of increased exposure within the environment
are widespread although some types of activity may be localized
to certain areas. For example, nuclear reactors are located in
nearly every state while uranium mining is confined primarily to
the west. The impact of these sources may also be widespread
due to releases to the atmosphere or to bodies of water.
Because much of the technology is of recent origin, the overall
impact is difficult to quantify due both to the relatively small
amounts of material and to lack of closure of the technological
cycle.
While radiation is known to be carcinogenic, mutagenic. and
teratogenic. much of the data obtained is from acute exposures
at high radiation levels. The effects of low level, long term
exposures are not well known. In addition, most of the
information obtained has been oriented toward human health
effects with less emphasis placed on other aspects of the
ecosystem.
II. Sources
Naturally Occurring Radioactivity
Any description of the sources of radioactivity should be
prefaced with the observation that radioactive material is
ubiquitous in the environment. Naturally occurring isotopes
such as hydrogen-3. carbon-14. and potassium-40. have been an
integral part of the ecology of the planet since its formation.
There are also four primordial radioactive series. The term
series connotes a chain of radioisotopes which sequentially
decay until a non-radioactive isotope is reached. For example.
the uranium series begins with uranium-238 which decays into
thorium-234 which decays into protactinium-234. Each decay
-------
-2-
is accompanied by the emission of radioactivity and there
are about thirteen decays in the chain, ending with the
stable (non-radioactive) isotope lead-206. Each secies is
characterized by a radionuclide with long half-life (the time
required for one half of the initial isotope to undergo decay).
in the millions to billions of years. The most abundant is the
thorium series (thorium-232. 14 billion years) followed closely
by the uranium series (uranium-238. 4.5 billion years). The
actinium series (uranium-235. 0.7 billion years) is much less
abundant in nature and the neptunium series (neptunicum-237. 2.1
million years) did not exist in recent times until recreated by
modern nuclear technology. Other radioisotopes. e.g..
hydrogen-3 and carbon-14. which occur in nature are also
produced in nuclear applications.
Anthropogenic Effects on Environmental Radioactivity
As noted, anthopogenically induced changes in the radiation
environment may be divided into those resulting from alteration
in the distribution of naturally occurring radioactivity and
those resulting from applications of nuclear technology. The
first category would include mining, milling, and other
industrial processes. The second category would include nuclear
reactors, including post-irradiation operations in the nuclear
fuel cycle, and particle accelerators. A discussion of each
category is given below and major sources in each summarized in
Table 1.
In the first category, increased exposure of the ecosystem
is due primarily to the collection or concentration of ores
containing radioactive materials. A prime example is the mining
and processing of uranium for use in the nuclear fuel cycle.
The mining process can expose and concentrate radioactive
materials and release it into the environment via wastewater
streams and the release of radioactive gases, notably radon.
whose decay products are also radioactive. The next step in the
cycle is milling of the ore. The uranium is removed and the
residue, including radium, placed in tailings piles. The
refined uranium is then sent to a diffusion plant where some of
it is enriched in the fissionable uranium-235 isotope. The
residual uranium, termed depleted, may be stored or used for
other purposes. The enriched uranium is sent to a fabrication
plant to be made into fuel rods for nuclear reactors. During
each phase of the processing, there is a potential for release
of radioactivity into the environment.
Due to the ubiquitous nature of the primordial series.
other industrial processes also contribute to the redistribution
of radioactivity in the environment. Thus, any mining operation
may transfer radioactive materials to the surface via mine
spoils or water discharges. Phosphate ores may contain
-------
-3-
Table 1
SuBBary of Dose Data froa All Source*
SOURCE
Aablent Ionising Radiation
CoeBlc radiation
Ionising component
Neutron component
Worldwide radioactivity
TrltluB
Carbon-14
Rrypton-85
Terrestrial radiation
Potaaslun-40
TrltluB
Carbon-14
RubldluB-87
FolonluB-210
Radon-222
Technologically Enhanced Natural
Radiation
Ore Blnlng and Billing
Uraolun Bill tailing*
Phosphate Blnlnlng and processing
ThoriuB a In Ing and Billing
Radon la potable water supplies
Radon In natural gaa
Radon in liquified petroleum gaa
Radon la Bine*
Radon daughter cxpoaure In
natural caves
Radon and geothermal energy production
Radioactivity In construction material
Medical Radiation
X radiation
Radlopharmaceutlctla
Occupational and Industrial Radiation
•UR
PUR
All occupation*
Consumer Product*
TV
Timepiece*
Nonlonislng Electromagnetic Radiation
•roadcaat tower* and airport radara
All sources
EXTERNAL INTERNAL
Individual
doaa
(orcB/y)
_
40.9-45
28-33.3
0.33-6.8
-
*
4x10 *
30-95
17
-
-
.
•13
"
—
_
-
-
-
-
_
-
-
_
-
-
Individual
doaa
(«a./y)
r20
C1230
C1080
"0.80
Y0. 02 5-0. 043
-
Population
doae
(per*on-reB/y)
9.7x10*
9.7x10*
9.2x10*
4.9xl05
-
-
80
-
-
.
-
.
-
-
-
_
-
-
-
-
.
-
.
»
.
-
Population
doae
(person-ram/y)
_
-
_
_
-
6100
6100
Individual Expoaure
(uW/ca2)
Individual
doaa
(Brem/y)
—
-
-
-
0.04
1.0
-
18-25
16-19
4x10"'
1.0
0.6
2-3
3.0
—
_
C140-14000
-
-
A
*54
0.9-4.0
.
w
-
-
Individual
doaa
(BTCB/y)
—
-
—
_
-
„
-
Population
doae
(pcrson-ram/y)
»
_ i
-
-
9.2x10
•
-
-
-
-
-
.
-
—
*
2.73x10*
_
*2. 5-70000
-
-
e
2.73x10
30000
-
•
.
-
Population
doae
(peraon-ram/y)
—
*3.3xl06
^
—
-
^
-
10
O.l-l
-------
-4-
Table 1 Cont'd
Susjury of Doae Data fro*, All Sources (Continued)
SOURCE
Fallout
Uranium Fuel Cycle
Mining, and •illlnc
Fuel enrichment
Fuel fabrication
Power raactora BUR
PUR
Research reactors
Transportation -
Xuclear power Industry
Radiolsotopea
Reproceaslns and spent fuel atoraie
Radioactive mate dlapoaal
Federal Facilities
CRDA
Department of Defenae
Accelerators
Rad lophamaceut icals-pr oduct Ion and
Dlapoaal
EXTERNAL
Individual
doaa
(«./y)
f 2
^
"0.17
.
•54 ...
* 1 •**
-
-
-
'5.8
•
•lJ-320
0.01
•0.04-4
0.2
Population
doae
(iterson-reWy)
-
2014
14
.
"1552
" 155
-
0 100
0 170
' 23
•
l.M
-l.M
-
0.42-65
*0.083
INTER.NAL
Individual
doae
(•re»/y)
-
*4.SxlO'2
*4. 3-8,0
"2X10'-1
_
-
-
-
-
-
—
_
-
-
.
Population
dost
(person-rea/y)
-
—
2.5
k j
_
-
-
-
-
-
—
.
-
-
.
a Uraniia-238 series
b Thoriia-232 series
c Lung dose
d Lung-re»/y
e Trachea-bronchial dose
f SO year dose connitment divided by SO
g Average individual lung dose vithin 80 kn
h Maximum potential exposure
i Maximum potential exposure to lung
j Cumulative exposure vithin 40 «ile radius
k Average individual lung dose vithin 80 km
m Fence line boundary dose
n Vithin a radius of 80 km
o Estimated for the year 1973
p For NFS
q Based upon data from S institutions
r Mllllrads/y
s Estimated 1980 dose
t Average occupational exposure/y
u Average exposure for all occupations & 3.7 radiation workers/1000 persons in United States
v 5 cm from TV set; units of mR/h
- • Ho dose data available
-------
-5-
radionuclides. usually in the uranium secies, and agricultural
uses can result in runoff. Thorium has varied industrial uses.
Historically, radium has been used for industrial and medical
purposes and residual contamination is not uncommon. The major
features of contamination by naturally occurring radioactivity
are the low specific activity and widespread distribution.
In the second category, that involving the application of
nuclear technology, the potential impact on the environment is
characterized by the production of concentrated, high specific
activity materials. A prime example of this is the nuclear fuel
cycle. The fuel rods mentioned above are placed into nuclear
reactors and the uranium induced to fission. The fission
process creates large, concentrated amounts of radioisotopes.
In normal operations, small amounts of these radioactive
materials may be released into the atmosphere or into
surrounding waters. Pollution control measures remove some of
this material which is disposed of as low level waste.
Catastrophic failure of a reactor may. of course, release
substantial amounts of radioactivity. The fuel rods must be
replaced periodically and since these "spent" rods are highly
radioactive, they must be cooled for long periods of time in
order to prevent their melting. In some instances, the spent
fuel is reprocessed to remove useful isotopes and the residue
disposed of as high level waste. Most of the commercial spent
fuel in this country will be disposed of. intact, as high level
waste.
The production of radioisotopes may also be accomplished in
particle accelerators. While the quantities involved are
smaller than in the reactor, substantial amounts of specific
isotopes may be produced for industrial and medical use. While
such material is normally tracked carefully, inadvertent
releases to the environment are not unknown. By contrast with
the naturally occurring series, the major aspect of nuclear
technology applications is the localized occurance of high
specific activity material.
Releases
Due to the complexity of the releases from various sources;
it is difficult to characterize them in readily understandable
form. That is. while detailed descriptions of the radioactive
material released in different operations are available, the
large numbers of radioisotopes involved tend to obscure their
overall impact. A more suitable measure of potential exposure
is the average radiation dose (the energy deposited per unit
mass of tissue) from each type of operation. Table 1 shows the
average annual external and internal doses expected for the
industrial sources listed. These doses are calculated for
humans - the dosimetry for most other flora and fauna is not
-------
-6-
well established - but are indicative of the relative magnitudes
of the impact on other parts of the environment. Radiation
doses are usually stated in terms of roentgens and rem - both a
measure of the energy deposited per unit mass of the receptor.
Multiples used in Table 1 and in the discussion below are milli
(1/1000). and kilo (1000) rad or rem.
Ecological Risk
One would expect two major types of radiation effects at
the community level (community being a natural grouping of
vegetation and animals). There should be an increase in the
frequency of deleterious mutations and cancer and a decrease in
the survival and vigor of the irradiated organisms - both of
which are very dose dependent. However, despite the increase in
mutations following acute or short term irradiation, the overall
genetic consequences may be of lesser importance than the acute
effects on the organisms. Most mutants would be similar to
those that occur spontaneously and would not be new to the
population. They would be present in increased numbers. If the
radiation exposure is of limited duration such that it does not
produce a long term change in the mutation rate (and if breeding
is at random, and if selective forces within the ecosystem are
not changed), then the incidence of a given mutant gene should
become stabilized at the level determined by the pressures of
natural selection, like that of any spontaneous mutation. There
should be no long term major increase in mutations. However.
with continuing or chronic irradiation, the increased incidence
of mutant genes could be sustained in the population.
In the US. exposures, absorbed doses, and dose equivalents
have historically been expressed in units of Roentgen (R). rad.
or rem respectively. Roentgen is a unit of exposure for x-rays;
a one rad absorbed dose in small animals, up to dog size, and
equivalent to 0.5 to 0.7 rad in large animals. Rad is a unit of
absorbed dose; a 1 rad absorbed dose is equivalent to a 1 rem
dose equivalent for x-rays and gamma rays and equivalent to 10
to 20 rem for alpha particles. Rem is a unit of radiation dose
equivalent that is. 1 rem of any type of ionizing radiation
yield the same long term effects.
Acute Exposure
It is likely that the major effect on a community is
related to the survival and vigor of the irradiated organisms.
Based on laboratory experiments, the radiosensitivities of the
various populations in a community are roughly: lethal exposure
for most mammals 200 R to 1000 R. fishes 1000 R to 10 kR; marine
animals 1000 R to 70 kR; insects 1000 R to 100 kR; flowering
plants 1000 R to 150 kR: and microorganisms between a few kR and
a million R (Vo81. IAEA73. Ne71. An86).
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— 7—
On land, the animals and motile insects ace dependent on
the plants, thus the/ will move into oc out of an acea as the
population of plants changes. Therefore, unless the mobility
oc availability of the animals is cestcicted naturally oc
artificially, most changes in communities ace associated with
altecations in the plant population. It has been determined
that herbaceous species ace moce cadiocesistant than woody
species and that dormant plants ace appreciably more resistant
than the same plants when actively growing. In addition, the
cadiosensitivity of a plant species has been shown to be celated
to the intecphase chromosome volume of the mecistematic cells
(Sp65).
In genecal. the gymnospecms have much highec chromosome
volumes and therefore, presumably are more radiosensitive than
the angiosperms. In other words, "pine-type" forests would be
more sensitive than deciduous or "hardwood" forests - LD100
values range from 500 R to 13 kR respectively (Ne7l).
Low exposures nay inhibit growth and reproductive capacity
of sensitive species temporarily but recovery should be rapid
and there should be no change in the composition of the plants.
It is possible that secondary damage could occur from
radioresistant-opportunistic insects or microorganisms but even
this effect would be short lived and the damage minor.
Excluding severe effects produced by massive exposures
sufficient to reduce the capacity of the site foe supporting
life, thece should be established an ocdecly succession leading
to an ecosystem basically similac to the system damaged.
These acute effects estimates ace included only to assure
completeness in the review of possible effects. Radiation
exposures in the environment of such magnitude are not expected.
bar major nuclear accident or nuclear war.
Chronic Exposure
Although there is a fair amount of data on the acute
effects of high levels of radiation on components of ecosystems
less is known of chronic effects.
Mutation rates in plants of 10~7 to 10~9 per rad per
locus; in insects of 10~6 to 10~8 per rad per locus and in
mammals of 10~6 to 10~8 per rad per locus have been reported
(UNSCEAR 72.77). The French have reported that the dose
response for genetic effects in some terrestcial plants is
lineac fcom background levels (10 iirad per hour) to about
10.000 iirad per hour. Mutation rates increased 10~7 to
10~8 per iirad/hr increase in exposure (De80).
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-8-
Impairment of reproductive and developmental functions
and genetic integrity have been observed in snail and fish
populations at exposure levels of less than 1 rad/day
(B166a. 66b. Hy80. Do64). However, other effects that might
be considered, hormesis have been noted starting at about 0.5
rad/day (Do64. Wi7l).
Ectoparasites have been more numerous on rodents and
lizards exposed to elevated levels of chronic radiation than on
controls in the desert ecosystem at the Nevada Test Site
(A162a. 62b). Ectoparasites on birds and mammals have been more
numerous in high natural radiation areas than in background
radiation areas in Northern taiga zones in Russia (Ma67).
The life span of pocket mice living in a radiation field of
1 to 2 rad/day was shorter than in control areas (Fr69. Fr70)
and some female lizards became sterile (Fr70). Degenerative
changes, reproductive and developmental problems have been
reported in animals in high natural background areas compared to
normal areas. These changes occurred not only in animals in
intimate contact with the soil. ie.. burrowing mammals, but also
in carnivores and birds with less intimate ground contact
(Ma67). Hovever. the possible contribution of radon daughters
to burrowing animal exposure was not evaluated. Thus, it
appears, in addition to the genetic and carcinogenic effects.
one would expect other detriment may occur in individuals in the
ecosystem exposed to ionizing radiation.
As noted earlier sources of increased radiation exposure in
the environment include: normal releases from nuclear reactors.
disposal of low level radioactive wastes, disposal of mine
spoils and mill tailings, disposal of soil contaminated with
natural radioisotopes. etc. Estimates of doses to various
components of the ecosystem are not available for most sources.
However, doses due to water discharges from some nuclear
reactors have been estimated. The estimates of maximum
radiation doses to biota in the vicinity of various reactors
range from 8 to 15.000 mrad/year for freshwater and marine
plants; 1 to 6100 mrad/yr in mollusks and crustaceans; 1 to 1800
mrad/yr in fin fish and 3 to 62000 mrad/yr in muskrats.
waterfowl and shore birds (Ka73).
Even though estimated detriment to individuals or
populations could be calculated, there are no criteria against
which to measure the estimated detriment. There is no criterion
to decide at what level of mutation load the situation should be
considered serious; no criterion for assessing what species or
diversification of species is considered good or bad. or what
the changes would mean; no criterion for how large an area must
be affected before it is worrisome, etc. The same is true for
carcinogenesis. reproductive and developmental impairment or any
other detriment.
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-9-
Likewise if reduced immuno-competency is indicated.
suggesting increased risk of zoonotic and/or indigenous disease.
at what level does this effect become important?
Until some criteria of impact are developed the expected
effect of radiation on ecosystems should be considered
undefined. While the effect has historically been considered
minimal and emphasis has been on pathways through ecosystems
that might effect man. radiation does have the potential of
causing disruption in ecosystems. The magnitude of disruption
would be expected to be related to the level and duration of
exposure. If there were criteria for evaluating severity it
might be possible to determine the grading of radiation sources
more exactly.
To the extent to which the question of the potential
ecological impact of various radiation sources has been examined
in the United States, there do not seem to be any ecological
disruptions. There may be areas of high background exposure but
these will usually be associated with high radon areas and are
expected to involve relatively small areas.Likewise reactor
liquid discharges, tailings piles, mine spoils and overburdens.
contaminated areas, etc. involve only small areas of land.
Possible ocean dumping of radioactive materials is a source of
potential impact which should be considered more seriously.
"Conventional wisdom" has been - if man is protected the
environment is protected. While this appears to be true it
would be nice to have ecological evaluation criteria to prove or
disprove this "wisdom".
III. Assessment
Overall, the impact of anthropogenic radioactivity would
appear to be minimal. Most potential sources are already
closely controlled and monitored. The current contribution from
human activities to the total radiation environment is small.
If the non-anthropogenic radiation dose is taken to be about 200
mrem per year, then fallout is approximately 10 percent of that
with nuclear activities adding another 1 percent. This
conclusion must be conditioned by the knowledge that the long
term effects of low level radiation are not well known and that
severe accidental releases may have large local consequences
coupled with more extensive, but lesser, global effects. At
present, however, this ecological problem should be rated as low.
-------
REFERENCES
A162d
-10-
Allred. D.M. and Beck. D.E. Ecological
Distribution of Mites on Lizards at the Nevada
Atomic Test Site. Herpetol. 18.:47-51 (1962).
A162b
Allred. D.M. Mites on Squirrels at the Nevada
Atomic Test Site. J. Parasitol. 48.:817 (1962)
An86
Anderson. S.L. and Harrison. F.L. Effects of
Radiation on Aquatic Organisms and Radiobioloqical
Methodologies for Effects Assessment.
EPA 520/1-85-016. US Environmental Protection
Agency. Washington. D.C. 1986.
B166a
Blaylock. B.C. Chromosomal Polymorphism in
Irradiated Natural Populations of Chironomus.
Genetics. 53.: 131 (1966).
B166b
Blaylock. B.C. Cytogenetic Study of a Natural
Population of Chironomus Inhabiting an Area
Contaminated by Radioactive Waste, pp. 835-846 in
Proc. Svmp.. Disposal of Radioactive Wastes into
Seas. Oceans, and Surface Waters. International
Atomic Energy Agency. Vienna. 1966.
De80
Delpoux. M.. Fabrics. M.. Faure. F.. Dulieu. H..
Leonard. A. and Dalebroux. M. Study of Genetic
Effects in Plants Induced by Natural Radioactivity
in Southwest France, pp. 1072-1076 in Natural
Radiation Environment III. Vol 2. CONF. 780422.
T.F. Gesell and W.M. Lowder. editors. US
Department of Energy. Washington. D.C.. 1980.
Do64
Donaldson. L.R. and Bonham. K. Effects of
Low-Level Chronic Irradiation of Chinook and Coho
Salmon Eggs and Alevirs. Trans. Am. Fish. Soc..
93:333 1964.
Fr69
French. N.R.. Maza. B.G. and Kaaz. K.W. Mortality
Rates in Irradiated Rodent Populations, pp. 46-52.
in Symposium on Radioecoloqy. CONF. 670503.
D.J. Nelson and F.C. Evans, editors. US Atomic
Energy Commission. Washington. D.C.. 1969.
-------
Ft70
-11-
Ftench. N.R.. Chronic Low-Level Gamma Irradiation
of a Desert Ecosystem for Five Years, pp. 1151-
1167; in Proc. Symp. International de
Radioecoloqie Cadarache. France. CONF. 690918. A.
Grauby. editor. US Atomic Energy Commission. Oak
Ridge. TN.. 1970.
Hy80
Hyods-Taguchi. Y.. Effects of Chronic
Y-Irradiation on Spermatogenesis in the Fish
Oryzias Latipes. with Special Reference to
Regeneration of Testicular Stem Cells, pp. 91-104.
in Radiation Effects on Aquatic Organisms. N.
Egami. Editor. (Japan Scientific Societies Press.
Tokyo: University Park Press. Baltimore. Nd.) 1980.
IAEA73
Environmental Behavior of Radionuclides Released
in the Nuclear Industry. Proceedings of a
Symposium organized by the IAEA, the OECD Nuclear
Energy Agency and the World Health Organization.
May 14-18. 1973
Ka73
Kaye. S.V. Assessing Potential Radiological
Impacts to Aquatic Biota in Response to the
National Environmental Policy Act (NEPA). pp.
649-661. in Environmental Behavior of
Radionuclides Released in the Nuclear Industry.
International Atomic Energy Agency. Vienna. 1973.
Ma 6 7
Ne71
Haslov. V.I.. Maslova. K.I. and Verkhouskaya. I.N.
Characteristics of the Radioecological Groups of
Mammals and Birds of Biogeocoenoses with High
Natural Radiation, pp. 561-571 in Radioecological
Concentration Processes. B. Aberg and F.P.
Hungate. editors. Pergamon Press. New York. 1967.
Radionuclides in Ecosystems. Proceedings of the
Third National Symposium on Radioecology May
10-12. (1971); Oak Ridge. TN.. Vol I and 2.
D.T. Nelson, editor. US AEC CONF-710501-P1&P2.
1971.
Sp65
Sparrow. A.H.. Relationship Between Chromosome
Volume and Radiosensitivity in Plant Cells;
pp. 199-222. in Cellular Radiation Biology.
Williams & Wilkins Co.. Baltimore. MD. (1965).
-------
-12-
Vo81 Natural Radiation Environment. Proceedings of the
Second Special Symposum on Natural Radiation
Environment; Jan. 19-23. 1981. Ed. by K.6. Vohra.
U.C. Mishra. K.C. Filial & S. Sadasivau.
John Wiley & Sons. 1982
Wi71 Williams. B.. and Murdock. M.B.. The Effects of
Contineous Low-Level Gamma Radiation on Estuarne
Microcosms pp. 1213-1221 Proc. of Third Nat'l.
Symposium on Radioecology. Vol. 2. CONF. 710501.
US Atomic Energy Commission. Oak Ridge. TN. 1971.
Wo77 Woodhead. D.S. The Effects of Chronic Irradiation
on the Breeding Performance of the Guppy. Poecilia
reticulata (Ostcichthys: Teleostei). Int. J.
Radiat. Biol. 32.:!. (1977)
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Problem 7. Stratospheric Ozone Depletion
OVERVIEW
Human activites are increasing the global atmospheric
concentrations of chlorofluorocarbons (CFCs), carbon dioxide,
methane, and several other trace gases. A growing body of
scientific evidence suggests that increasing concentrations of
these gases may deplete the stratospheric ozone layer, which
shields the earth from harmful ultraviolet radiation (UV-B).
Increases in UV-B could adversely affect terrestical and aquatic
ecosystems. Additional stresses could result from the links
between trace gas concentrations, changes in stratospheric
structure, and global climate change (see Problem # 8).
SOURCES AND QUANTITIES OF POLLUTANTS RELEASED
The main anthropogenic cause of ozone depletion is
attributed to CFCs, a family of compounds used worldwide as
aerosol propellants, foam blowing agents, refrigerants, and
solvents. World production of CFC-11 and CFC-12, the most
commonly used CFCs, was 703 million kilograms in 1985, up from
695 million kilograms in 1984. In developed countries, historical
use of CFCs has kept pace with economic growth — annual changes
in CFC use have averaged approximately twice the growth rate of
GNP. other CFCs, particularly CFC-113, which is used in the
electronics industry, have grown much faster. CFCs persist in the
atmosphere. The lifetimes of CFC-11 and CFC-12 are 75 years and
150 years. Virtually all CFCs manufactured are eventually
released to the atmosphere.
ECOLOGICAL EFFECTS AND ASSESSMENT
Recent modelling results show that if CFCs and other trace
gases grow at recent rates, global average ozone depletion could
reach 6.5 percent by the year 2030. However, depletion would vary
by season and latitude. Regions such as the Northern U.S. and
Northern Europe would experience significantly higher depletion.
At 60 degrees North, depletion could reach 16 percent in Spring.
Even with constant CFC emissions, annual average depletion would
reach 8 percent in the high Northen latitudes. A one percent
depletion of ozone leads to roughly a two percent increase in
harmful UV-B radiation.
Increases in UV-B would affect both aquatic and terrestial
ecosystems. The aquatic resources most affected by UV-B would be
phytoplankton and larvae of several fish species, particularly
crabs, fish, and anchovies. Of the more than two hundred
terrestial plants that have been tested in the laboratory, two-
thirds have reacted adversely to increased UV-B. These and other
far more limited field tests suggest that some cultivars may be
more susceptible to UV-B damage than others. For both aquatic and
terrestial ecosystems, both the productivity of particular
species and the competitive balances among different species
would be affected.
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Problem f7 Stratospheric Ozone Depletion
Human activities are increasing the worldwide atmospheric
concentrations of chlorofluorocarbons, carbon, dioxide, methane,
and several other gases. A growing body of scientific evidence
suggests that if these>trends continue, stratospheric ozone may
decline and global temparature may rise. Because the ozone layer
shields the earth's surface'from damaging ultraviolet radiation
(UV) future depletion could increase the incidence of skin cancer
and other diseases, reduce crop yields, damage materials, and
place additional stress on aquatic plants and animals. This
additional stress would result in part because some of the same
trace gases which affect stratospheric ozone are also "greenhouse"
gases linked with a rapid global warming (see problem |8 - CC>2
and Global Warming) .
Atmospheric Processes
The ozone in the upper part of the atmosphere—known as the
stratosphere—is created by ultraviolet radiation. Ordinary oxygen
(02) is continuously converted to ozone (03) and back to 02 by
numerous photochemical reactions that take place in the stratosphere
as Stordal and Isaksen (1986) describe. Chlorofluorocarbons and
other gases released by human activities could alter the current
balance of creative and destructive processes. Because CFCs are
very stable compounds, they do not break up in the lower atmosphere
(known as the troposphere). Instead, they slowly migrate to the
stratosphere, where ultraviolet radiation breaks them down,
releasing chlorine.
Chlorine acts as a catalyst to destroy ozone; it promotes
reactions that destroy ozone without being consumed. A chorine
(Cl) atom reacts with ozone (63) to form CIO and 02« The CIO
later reacts with another 03 to form two molecules of 02» which
releases the chlorine atom. Thus, two molecules of ozone are
converted to three molecules of ordinary oxygen, and the chlorine
is once again free to start the process. A single chlorine atom
can destroy thousands of ozone molecules. Eventually, it returns
to the troposphere, where it is rained out as hydrochloric acid.
Atmospheric models are utilized to examine possible future changes
to the ozone layer from increased atmospheric concentrations of
CFCs and other gases .
At a recent conference sponsored by EPA and UNEP, Stordal
and Isakson presented results of possible ozone depletion over
time, using their two-dimesional atmospheric chemistry model.
Unlike one-dimensional models which provide changes in ozone in the
global average, this model calculates changes for specific latitudes
-------
-2-
and seasons. Hie results show that if concentrations of the
relevant trace gases grow at recent levels, global average ozone
depletion by 2030 would be 6.5 percent. However, countries in
the higher latitudes (60°N) would experience 16 percent depletion
during spring. Even in the case of constant CFC emissions, where
global average depletion would be 2 percent by 2030, average
depletion would be 8 percent in the high northern latitudes.
Watson (1986) presents evidence that ozone has been
changing recently more than atmospheric models had predicted.
The ozone over Antarctica during the month of October appears to
have declined over 40 percent in the last six to eight years.
Watson also discusses observations from ozone monitors that
suggest a 2 to 3 percent worldwide reduction in ozone in the
upper portion of the stratosphere (thirty to forty kilometers
above the surface), which is consistent with model predictions.
Whether or not these changes are directly related to CFCs has not
been scientifically established to date.
Sources and Quantities Released
The major anthropogenic cause of ozone depletion is attributed
to chlorofluorocarbons (CFC) a family of compounds used world
wide for aerosol propellants, rigid foams, flexible foams, refri-
geration, air conditioning and industrial cleaning. Production
of CFC 11 and 12, the most commonly used CFCs was 703,200 metric
tons in 1985, up from 694,500 metric tons in 1984. The yearly
increase in world production averages about 2 to 3% per year and
has increased at this level since production began in the 1950s.
Lifetime persistence in the atmosphere for CFC 11 is 75 years,
and for CFC 12 is 110 years. Virtually all CFC's manufactured
eventually are released into the atmosphere.
Affects on Aquatic Organisms
Aquatic plants would likely be adversely affected by increased
ultraviolet radiation. Wbrrest; (1986) points out that most of
these plants, which are drifters (phytophlankton), spend much of
their time near the surface of the water (the euphotic zone) and
are therefore exposed to ultraviolet radiation. A reduction in
their productivities would be important because these plants
directly aSid indirectly provide the food for almost all fish.
Although these plants might move deeper to avoid UV-B radiation,
such shifts would reduce their photosynthetic productivity.
Furthermore, the larvae of many higher order fish which are found
in the euphotic zone would be directly affected, including crabs,
shrimp, and anchovies. Worrest points out that fish account for
18 percent of the animal protein that people around the world
consume, and 40 percent of the protein consumed in Asia.
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-3-
An important question is the extent to which current UV-B
levels are a constraint on aquatic organisms. Calkins and
Keller (1984) conclude that some species are already exposed to
as much UV-B as they can tolerate. Thomson (1986) shows that a
10 precent decrease in ozone could increase the number of abnormal
larvae as much as 18 percent. In a study of anchovies, a 20
percent increase in UV-B radiation over a 15-day period caused
the loss of all the larvae within a 10-meter mixed layer in April
and August. Increased UV-B radiation could not only have serious
direct effects on aquatic organisms but also serious indirect
effects as significant reductions in the populations of lower
trophic level organisms alters the competitive balance of organisms
at higher tropic levels. Serious changes in community structure
and function could result. This impact would be global in scope,
continuous and irreversible.
Effects on Plants
The effects of increased exposure to UV-B radiation on plants
has been a primary area of research for nearly a decade. Teramura
(1986) reports that of the two hundred plants tested for their
sensitivity to UV-B radiation, over two-thirds reacted adversely;
peas, beans, squash, melons, and cabbage appear to be the most
sensitive. Given the complexities in this area of research, he
warns that these results may be misleading. For example, most
experiments have been in growth chambers. Studies of plants in the
field have shown them to be less sensitive to UV-B.
Bjorn (1986) examines the mechanisms by which plant
damage occurs. His research relates specific wavelengths with
those aspects of plant growth thatvmight be susceptible, including
the destruction of chloroplast, DNA, or enzymes necessary for
photosynthesis. Increased UV-B radiation could substantially
alter the competitive balance favoring vegetation that is less
sensitive to UV-B radiation, which would come to dominate.
Serious changes in community structure and function would likely
result. This potential impact would be global in scope, and
continuous.
CLIMATE CHANGE
The Greenhouse Effect
Concern about a possible global warming focuses largely on
the same gases that may modify the stratospheric ozo>ne : carbon
dioxide, methane, CFCs, and nitrous oxide. The report of a recent
conference convened by UNEP, the World Meteorological Organization,
and the International Council of Scientific Unions concluded that
if current trends in the emissions of these gases continue, the
-------
earth could warm a few degrees (C) in the next fifty years (Villach
1985). In the next century, the planet could warm as much as five
degrees (NAS 1983), which would leave the planet warmer than at
any time in the last two million years. For a complete discussion
of the global warming impacts on ecosystems, see problem 18, "CC«2
and global warming".
Controllability
Because there are time lags of decades between changes in
emission rates, atmospheric concentrations, and changes in ozone,
the types of management strategies must be different from those
that are appropriate for controlling, for example, particulate
pollution, where the problem goes away as soon as emissions are
halted. CFC emissions would have to be cut 80 percent simply to
keep atmospheric concentrations from increasing. Considerable
reduction in CFCs are possible through existing technologies
including: carbon absorption, reduced leakage, and substitute
products and chemicals. Moreover, the production of more beniqn
CFCs may be possible within the next decade.
Assessment
Doniger and Wirth, from the Natural Resources Defense Council
(U.S.), argue that the current uncertainties are no longer a
reason to wait for additional information: "With the stakes so
high, uncertaintly is an even more powerful argument for taking
early action." These authors conclude that sharp reductions in
CFCs are necessary, pointing out that even with a production cap,
atmospheric concentrations of these gases will continue to grow.
Therefore, Doniger and Wirth propose an 80 percent cut in production
over the next five years for CFCs 11 and 12, the halons, and
perhaps some other compounds, with a complete phaseout in the
next decade.
Gus Speth, president of the World Resources Institute,
recommends a production cap for chlorofluorocarbons and agrees
with Topping that environmental impact statements for projects
that could contribute to ozone modification should consider these
impacts.
The severity of the potential ecological impacts that could
result from increased UV-B radiation, the global scale of such
impacts and their irreversibility more than offsets the associated
uncertainties. This environmental problem is global in scale,
and its intensity of impact on ecosystems is potentially very high.
-------
References
Calkins, J., and C.I. Keller (1984) "Solar UV and its Impact
on Microorganisms in Aquatic Ecosystems", prepared for the
U.S. EPA.
Stordal, Frode and Ivan Isakser; "Ozone Perturbations Due to
Increases in N2O, CH4 and Chlorocarbons: Two-dimensional
Time Dependent Calculations" in Effects of Changes in
Stratospheric Ozone and Global Climate, Vol. I Overview,
U.S. EPA, August 1986.
Teramura, A.H. (1986) "Overview of Our Current State of
Knowledge of UV Effects on Plants", in EPA (1986), Effects
of Changes in Stratospheric Ozone and Global Climate.
Volume I: Overview, U.S. EPA, Washington, D.C.
Thomson, B.E.; " ", in Effects of Changes in
Stratospheric Ozone and Global Climate, Vol. II; forthcoming
Villach, (1985) International assessment of the role of
carbon dioxide and of other greenhouse gases in climate
variations and associated impacts. Conference Statement.
Geneva: United Nations Environment Program.
Watson, Robert; "Atmospheric Ozone" in Effects of Change in
Stratospheric Ozone and Global Climate, Vol. I; Overview,
U.S. EPA, August 1986.
Worrest, R.C. (1986) "The Effect of Solar UV-B Radiation on
Aquatic Systems: An Overview", in EPA (1986), Effects of
Changes in Stratospheric Ozone and Global Climate,. Volume I;
Overview, U.S. EPA, Washington, D.C.
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Problem 8. C02 and Global Warming
OVERVIEW
In recent decades, the concentrations of greenhouse gases
have been increasing. Since the industrial revolution, the
combustion of fossil fuels, deforestation, and other
anthropogenic influences have released enough CO2 into the
atmosphere for concentrations to rise 20 percent since the late
19th century — 8 percent since 1958. An international conference
of scientists and policymakers recently convened in Villach
Austria and concluded that by the year 2030, increases in C02 and
other greenhouse gases, particularly chlorofluorocarbons (CFCs),
methane, and nitrous oxide, would ensure a global temperature
increase of 1.5 to 4.5 degrees Centigrade. An increase of this
size and speed is unprecented in human history.
CONCENTRATIONS OF POLLUTANTS RELEASED
Increases in future C02 emissions are expected as future
economic and population growth contribute to increased fossil
fuel combustion and deforestation. An analysis prepared for the
National Academy of Sciences projects that by the year 2065,
atmospheric C02 concentrations will have reached twice the pre-
industrial level. The concentrations of other greenhouse gases
are also increasing: CFC-11 and CFC-12 at 5 percent per year,
methane at 1 percent per year, and nitrous oxide at 0.2 percent
per year. As with CO,, emissions are related to population and
economic growth, ana future increases are likely.
ECOLOGICAL EFFECTS AND ASSESSMENT
A change in global climate of the size and speed forseen at
the Villach Conference would have major implications for
ecosystems. One of the most widely recognized consequences would
be a rise in sea level resulting from thermal expansion of the
oceans, and changes in ice fields. By the year 2100, a rise in
sea level of 90 to 170 centimeters is likely. Such an increase
would innundate low-lying areas, destroy coastal marshes and
swamps, erode shorelines, exacerbate coastal flooding, and
increase the salinity of rivers, bays and aquifiers.
Changes in temperature and key hydrological variables such
as precipitation, evaporation, soil mositure and runoff would
have serious implication for terrestial ecosystems. Changes in
net biomass and biomass composition are also likely.
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Problem 18- CO? and Global Warming
In recent decades, the concentrations of greenhouse gases
have been increasing. Since the beginning of the industrial
revolution, the combustion of fossil fuels, deforestation, and
a few other activities have released enough CC>2 to raise
atmospheric concentrations by 20 percent; concentrations have
risen 8 percent since 1958 (Keeling, Bacastow, and Whorf 1982).
More recently, Ramanathan et al. (1985) examined the greenhouse
gases other than C02 (such as methane, CFCs, and nitrous oxide),
and concluded that these other gases are likely to double the
warming caused by C02 alone. Using these results, the Villach
Conference estimated that an "effective doubling" of COo is
likely by 2030.
This increase will cause global temperatures to increase
1.5°-4.5°C over the next 50-75 years. Such a rapid climate
change is unprecedented. The magnitude of change is roughly
equivalent to the difference between the last Ice Age (18,000
years ago) and today.
Sources and Quantities Released
The total quantity of CC>2 emitted is calculated as the
product of fuel used in each time period and CC>2 emitted per
unit quantity of each fuel. The following CC>2 (carbon)
emission coefficients are employed (Edmonds and Reilly,, 1983a):
COa Emissions (Terragrams of Carbon/EJ)
Fuel Preparation Combustion Total
Conventional Oil — 19.7 19.7
Unconventional Oil 27.9 19.7 47.6
(Shale Oil)
Gas — 13.8 13.8
Coal ~ 23.9 23.9
Synthetic Oil 18.9 19.7 38.6
(from coal)
Synthetic Gas 26.9 13.9 40.7
(from coal)
All other fuels are assumed to contribute no C02 to the
atmosphere.
-------
The amount of CO2 in the atmosphere has been steadily
increasing for several decades as indicated by the graph on the
next page.
Nitrous oxide (N2O) emissions result primarily from combus-
tion of fossil fuels and biological dentrif ication processes in
soil. By increasing the use of nitrogen fertilizers and by
adding nitrogen-rich sewage to water bodies, we are indirectly
adding nitrous oxide to the atmosphere. Measurements of N2O
concentrations from 1970 to 1980 show an increase of 6 parts per
billion (ppb) to a level of 295 ppb (Lacis, 1981). Estimates
suggest that a doubling of nitrous oxide would directly increase
temperature by 0.30-0.44°C (Conner and Ramanathan, 1980; Wang
and Sze , 1980). In addition, increases in N2O may indirectly
contribute to an even greater warming. Wang and Sze have calcu-
lated that the resulting indirect greenhouse warming could raise
temperature another 0.18°C for a total increase of 0.48-0.62°C
due to a doubling of N20.
As more fossil fuels are used, ^O emissions are likely to
increase. Also as greater demands are placed on world food
supplies, increased use of nitrous oxide-producing fertilizers
is likely. However, because the natural sources and sinks of
this trace gas are not well understood, more research is required
before reliable projections can be made of future levels.
METHANE
Methane (CH4), is a second important trace greenhouse gas.
The known sources of CH4 are anaerobic fermentation in rice
fields and swamps, and enteric fermentation from termites, cows,
and other animals. As the need for food from livestock and
rice fields increases over time, atmospheric levels of CH4 are
likely to increase. In addition, increases in carbon monoxide
(from fuel combustion) in the troposhere lowers the concentration
which destroys methane. Based on current estimates of a 2 percent
per year increase in concentration, by the middle of the next
century CH4 could increase global warming by about 0.2-0.3°C
(Lacis, 1981).
Future increases in methane could, however, be far higher
than the estimated 2 percent per year of the recent past. As
the earth warms, extensive peat bogs containing as much as
2000 gigations of CH4 in the form of methane hydrates now
frozen in northern latitudes may thaw, releasing considerable
quantities of this gas into the atmosphere. While much of
-------
MONTHLY ATMOSPHERIC CARBON DIOXIDE CONCENTRATION AT MAUNA
LOA OBSERVATORY*
340
336
332
328
324
320
316
312
I I I I
J 1
1 I I I
1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980
*Seasonal effects have been normalized.
Source: CEQ (1981), based on data derived from Keeling, Scripps
Institute of Oceanography.
-------
this methane is buried 250-1,000 meters under the ground and
therefore, unlikely to be released for several centuries, a
contribution of eight gigatons per year from methane hydrates
under shallow water is possible within the next 100 years
(Bell, 1982).
For quantitative information on CFCs, see problem #7
"Stratospheric Ozone Depletion."
Effects on Fresh Water Resources - Lakes, Rivers and Wetlands
There is evidence that climate change since the last Ice
Age 18,000 years B.P. has significantly altered the location
of lakes although the extent of present day lakes is broadly
comparable with 18,000 years B.P. For example, there is
evidence indicating the existence of many lakes and swamps
in the Sahara, Arabian and Thor Deserts around 9-8,000 years
B.P.
The inextricable linkages between the water cycle and
climate insure that potential future climate change will
significantly alter hydrological processes throughout the
world. All natural hydrological processes — precipitation,
infiltration, storage and movement of soil moisture, surface
and subsurface runoff, recharge of groundwater and evapor-
ranspiration — will change if climate changes.
As a result of changes in key hydrological variables such
as precipitation, evaporation, soil moisture and runoff;
climate change is expected to have significant effects on
water availability. Early hydrological impact studies provide
evidence that relatively small changes in precipitation and
evaporation patterns might result in significant, perhaps
critical, changes in water availability. For many aspects
of water resources — including human consumption, agricultural
water supply, flooding and drought management, groundwater use
and recharge and reservoir design and operation—these hydro-
logic changes will have serious implications.
Despite significant differences among climate change
scenarios, a consistent finding among hydrologic impact studies
is the prediction of a reduction in summer soil moisture and
the timing and magnitude of runoff. Winter runoff is expected
to increase and summer runoff may decrease.
-------
Effects on Coastal Estuaries and Tidal Wetlands
One of the most widely recognized consequences of a global
warming would be a rise in sea level. As Titus (Volume 1) notes,
global temperatures and sea level have fluctuated over periods of
one hundred thousand years, with temperatures during ice ages
being three to five degrees (C) lower and sea level over one
hundred meters lower than today. By contrast, the last inter-
glacial period (one hundred thousand years ago) was one or two
degrees warmer than today, and sea level was five to seven meters
higher.
The projected global warming could raise sea level by heating
and thereby expanding ocean water, melting mountain glaciers, and
by causing polar glaciers in Greenland and Antarctica to melt and
possibly slide into the oceans. Thomas (Volume 4) presents new
calculations of the possible contribution of Antarctica and
combines them with previous estimates for the other sources,
projecting that a worldwide rise in sea level of 90 to 170
centimeters by the year 2100 with 110 centimeters most likely.
The projected rise in sea level would inundate low-lying areas,
destroy coastal marshes and swamps, erode shorelines, exacerbate
coastal flooding, and increase the salinity of rivers, bays,
and aquifers.
Park et al. (Volume 4) focus on the expected drowning of
coastal wetlands in the United States. Using a computer model
of over 50 sites, they project that 40-75 percent of existing
U.S. coastal wetlands could be lost by 2100. Although these
losses could be reduced to 20-55 percent if new wetlands form
inland as sea level rises, the necessary wetland creation
would require existing developed areas to be vacated as sea
level rises, even though property owners would frequently
perfer to construct bulkheads to protect their property. Because
coastal wetlands are important for many commerically important
seafood species, as well as birds and furbearing animals, Park
et al. conclude that even a one-meter rise in sea level would
have major impacts on the coastal environment.
DeSylva (Volume 4) also examines the environmental impli-
cations of sea level rise, noting that in addition to wetlands
being flooded, estuarine salinity would increase. Because 66
to 90 percent of U.S. fisheries depend on estuaries, he writes
that these impacts could be important. He also suggests that
coral reefs could become vulnerable because of sea level rise,
increased temperatures, and the decrease in the pH (increased
acidity) of the ocean.
-------
Effects on Terrestrial System
The greenhouse warming could affect agriculture by altering
water availability, length of growing season, and the number of
extremely hot days. Global climate change would also likely
alter the composition of biomass significantly. Solomon predicts
a net decline in forest biomass of 10% (11 MT/HA). A potential
shift of the lobolly Pine region is also pred icted.
Predicted decreases in summer soil moisture and increases
in the frequency of prolonged high temperature events would
likely have significant impacts on the vegetation especially
those in marginal lands. The main effects likely to occur
will be physical impacts from changes in thermal regimes,
moisture stress, and levels and timings of pest infestation.
Controllability
Because there are time lags of decades between changes in
emission rates, atmospheric concentrations, and changes in ozone,
the types of management strategies must be different from those
that are appropriate for controlling, for example, particulate
pollution, where the problem goes away as soon as emissions are
halted. A worldwide ban on coal instituted by 2000 would reduce
temperature change for 2100 by 30% (5°C to 3.5°C). Together, a
ban on shale oil and coal would reduce the projected warming in
2100 from 5°C to 2.5°C. Reductions in CFCs would also substantially
decrease the projected warming.
Although society is probably locked into a 2°C warming due to
past emissions and expected emissions in the next decade, it is
not too late to prevent the more disruptive 5° warming. Because
of the time lag, however, the difficult and complex international
options for limiting the warming must be developed soon if they
are to be effective.
Assessment
The severity of the potential ecological impacts that could
result from such unprecedented rate of global warming, the global
scale of such impacts and their irreversibility warrants serious
attention despite the substantial uncertainties that exist
regarding the timing of the climate changes and their specific
regional and ecological impacts.
-------
References
Bell, P.; "Methane Hydrate and the Carbon Dioxide Question" in
Clark (ed.)f Carbon Dioxide Review 1982, New York:
Oxford University Press.
Donner L, and V. Ramanathan (1980) "Methane and Nitrous Oxide:
Their Effects in Terrestrial Climate", J.J. Atmospheric
Science, 37, 119.
Edmonds J. and J. Reilly (1983) "A Long Term Global Energy
Economic Model of Carbon Dioxide Release from Fossil
Fuel Use", Energy Economics, 5, 74.
Keeling, C.D. , R.B. Bacastow and T.P. Whorf (1982) Measurement
of the concentration of carbon dioxide at Mauna Loa,
Hawaii, Carbon Dioxide Review, ed . by W. Clark. New York:
Oxford University Press.
Ramanathan, V., R. Cicerone, H. Singh and T. Kiehl; (1985),
Trace gas trends and their potential role in climate
change. J . Geophep . Res . 90:5547-66.
Titus, J. "The Causes and Effets of Sea Level Rise" in Effects
of Changes in Stratospheric Ozone and Global Climate
U.S. EPA, August 1986.
Wang, W. , and N. Sze (1980), "Coupled Effects of Atmospheric
N20 and 03 in the Earth Climate", Nature 286, 589.
-------
JMN-796?
Problem Sources 9 and 10: Direct and Indirect Point Source
Discharges to Surface Waters
Stress Agents
Permitted dischargers to surface waters are collectively the
largest source of priority pollutants (organic and inorganic
toxicants) being released to the ambient environment. They are
also major sources of both conventional pollutants (BOD and TSS),
and important nonconventional pollutants such as chlorine and ammonia.
Sources
Approximately 65,000 point sources are permitted to discharge
pollutants directly into U.S. waters. Most of these sources are
clustered around industrialized population centers in the East
and in aggregate constitute a regional problem for this half of
the country. Because aquatic resources are limited and industrial
development less concentrated west of the Mississippi, problems
caused by point sources tend to be somewhat more localized in
this region.
Exposures and Impacts
Rough modelling projections of potential ecological impacts
from point sources estimate that over 50% of the stream reaches
receiving permitted discharges could be deleteriously affected
by toxic and/or conventional pollutants. Of the lotic and
estuarine waters that have actually been assessed, 40-50% of the
impacts are considered due to point sources; impacts to lentic
systems are more commonly caused by nonpoint sources.
Current Controls
Most current discharge limits are technology-based rather
than water quality-based. Technology-based controls consider the
economic feasibility of significantly improving treatment on a
national rather than a local scale, and therefore may not be
protective of a particular waterbody. Site-specific water quality-
based controls are meant to be implemented where additional
controls are needed; they are relatively difficult to develop and
administer, however, and are not likely to be in place for 5 to
10 years.
Data Quality
Although massive quantities of data are available on
chemical effluent and ambient water quality, information on the
actual ecological status of aquatic receiving systems is often
lacking or inaccessible, and therefore site-specific conclusions
should not be drawn. However, at the level of organization most
relevant to this project - the national level- the existing data
-------
are clearly sufficiently to establish point sources dischargers
as a major source of both potential and real impact to aquatic
ecosystems.
Overall Importance
As the primary source of toxic pollutants and a major
contributor of numerous other stress agents to aquatic systems,
point source discharges have an extremely high potential for
causing profound and widespread impacts. From an ecological
perspective, point source discharges should be one of the highest
priority problem areas.
-------
Problem Sources 9 and 10: Direct and Indirect Point
Source Discharges to Surface Waters
I. INTRODUCTION
Approximately 65,000 waste treatment facilities are permitted
to discharge pollutants directly into the nation's navigable
surface waters. Of these, roughly 39,000 have been categorically
identified as important sources of both conventional (e.g., BOD,
TSS) and toxic pollutants; 24,000 industrial plants and 15,000
POTWs (Table 1). About 17 percent of the POTWs receive significant
inputs from the categorical industries (indirect discharges) and
are, therefore, of particular concern as potential sources of impact
to aquatic ecosystems.
Most point sources are located in the more heavily populated
and industrialized regions of the U.S. Figure 1 shows the
geographic distribution of the 7,000 largest permitted dischargers;
3,200 industrial plants and 3,800 POTWs. These dischargers are
most densely clustered in the midwest and eastern regions of the
country where human populations and industrial development have
been historically dependent upon abundant aquatic resources.
The figure clearly illustrates the profound potential for regional
as well as localized impacts from permitted point sources.
As presently regulated, point source controls are implemented
through a system of permits (NPDES) which do allow the discharge
of both conventional and hazardous materials, but place limits on
the amount and concentrations that may be released. Discharge
requirements have historically focused on limiting conventional
pollutants, and although emphasis has shifted to controlling
toxics in the last ten years, most current requirements are
technology-based rather than water quality-based. Technology-based
controls consider the economic feasibility of significantly
improving treatment on a national rather than a local scale and
are not specifically designed to protect any given waterbody.
Where dischargers are closely clustered or receiving system
dilution is low, there remains a significant likelihood of
impact, even with full implementation of Best Available Treatment
(which is far from complete) and perfect compliance (which is
far from true).
Fully regulated discharges are not the only point sources of
concern. Regular but unpermitted discharges may be significant
in some areas (GAO, 1983), and illegal releases of acutely toxic
wastes into aquatic systems may be more common than previously
believed (TSD, 1985). Combined sewer overflows and storage
impoundments also sporadically release discharges that can cause
severe impacts in certain areas.
-------
II. Sources, Stress Agents, and Exposures
•
Sources
The point source discharge categories considered of primary
national importance are listed in Table 1. These categories
have been identified as the major dischargers of priority organic
and inorganic toxics as well as conventional pollutants. Most
of these industries have in-pipe pollutant concentrations that
are several times the ambient water quality criteria, and therefore
have the potential to cause major impacts, depending on the
specific discharge situation. As a single .categorical source,
POTWs are clearly of primary importance in terms of numbers and
post-BAT loadings of both conventionals and toxics. It should be
noted that a significant proportion of the total toxics loads
discharged from POTWs is contributed by industrial indirect
dischargers (13% of all organics and 52% of all inorganics; see
Table 2 and "Note", Table 1). This is particularly significant,
considering only 17% of the POTWs receive indirect industrial
discharges.
Stress Agents
Virtually all of the stress agents identified by the Cornell
Workgroup eminate in quantity from point source dischargers.
Point sources unquestionably discharge more toxics than any other
source and are major contributors to national loadings of BOD,
solids, nutrients and chlorine. POTWs are also major dischargers
of ammonia which is a potent toxicant to aquatic animals and a
source of nitrogenous nutrients to aquatic plants. (Also see
Cornell Workshop draft report and Attachment A for brief discussion
of stress agents and their general effects on ecosystems)
Exposures
The total number of river reaches receiving major industrial
and POTW discharges in each of the nation's 18 hydrologic regions
(Figure 2) is provided in Table 3. These data indicate that
approximately 16% of all the nation's "river" reaches and 26% of
the "river" miles receive at least one major discharge and that
most of these are located in the eastern regions of the U.S.
Table 4 provides a similar breakdown for just the POTWs, both
those with indirect industrial inputs and those without.
Unfortunately, this summary does not permit precise character-
ization of the particular type of aquatic system receiving the
discharge i.e., buffered vs. unbuffered stream, coastal vs.
estuarine system. However, certain gross generalizations are
possible:
1) Point source dischargers are very densely clustered in the
northeast where aquatic systems are poorly buffered and therefore
more sensitive to impact.
2) Point sources are clustered near the mouths of rivers where
they are likely to impact bays and estuaries.
-------
3) POTWs are more evenly distributed across the country than
industrial facilities; therefore impacts from POTW-related
pollutants (BOD, TSS, chlorine, ammonia) may be of greater concern
to the western regions than priority pollutants.
III. Ecological Effects
Predicted Impacts
An earlier issue paper (Attachment A) described the general
ecological effects caused by the aforementioned stress agents,
most of which are generated by point source dischargers to surface
waters. In order to generically assess the potential for ecological
impact from point sources after full implementation of BAT, a
national dilution analysis was performed. The objective of the
analysis was to: 1) predict instream concentrations for BOD and
selected organic and inorganic pollutants on a reach-by-reach
basis and 2) compare these projected concentrations with estimated
effects criteria. Table 5 summarizes the results from the analysis
based on 21,000 facilities (vs. a total of 39,000), for which
sufficient data is available. Of the reaches receiving these
point source discharges (14% of the nation's total), approximately
57% are projected to exceed one or more of the toxic "criteria"
under low flow conditions (11% at mean flow). In addition, 29%
of these reaches could be impacted by BOD loadings, even if
nonpoint sources, probably the primary contributors of BOD, are
completely ignored.
Direct Assessments
Preliminary analysis of 1986 State 305(b) reports provides
data from direct observations of ambient water quality conditions.
Forty States have provided information on approximately 22% of
the nation's waters - primarily those that actually receive
permitted discharges.
1. Rivers and streams: of the 328,000 miles assessed, 28%
do not fully support designated uses; of these, 41% are
impaired by point sources.
2. Lakes: 25% of the lake acres assessed do not fully
support designated uses; of these, 15% are primarily
impaired by point sources.
3. Estuaries: of the 2 million square miles assessed, 16%
do not fully support designated uses; of these 49% are
primarily impaired by point sources.
4. Coastal waters: only 1,500 miles of coastline were
assessed (2 States); of these 11% were found impaired
and 58% by point sources.
-------
IV. Evaluation
As the single largest source of toxics (including chlori-
nation products and ammonia) and a primary contributor of BOD,
solids, nutrients, and thermal pollution, point dischargers pose
an immediate and widespread threat to the nation's surface waters.
Although pollutant loadings have been drastically reduced (relative
to raw waste waters) with the promulgation of technology-based
treatment requirements, significant impacts are still likely
where dischargers are clustered and/or receiving systems provide
limited dilution. This situation is most likely to occur near
industrialized population centers. These are commonly located on
major inland waterways or near coastal estuaries, but may also
occur near smaller aquatic systems along important overland
transportation routes or material resource centers. Thus the
question is not so much "if" the impacts to aquatic systems are
significant, but instead "where" will these impacts actually
occur and how can the necessary water quality-based controls be
put in place.
The source data and direct observations provided in this
paper essentially confirm the likelihood of impacts predicted by
the Cornell Workgroup (Figure 3). In addition, these data
indicate that potential impacts associated with point source
discharges may be of "high" magnitude on a regional as well as a
local scale, at least for the eastern half of the country.
Focus should be placed on point discharges as the major source
of ecologically important toxics and second only to nonpoint
sources with respect to BOD and solids loadings.
-------
-------
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-------
TABLE 1
SUMMARY OF TOTAL POLLUTANT LOADIN6S
BY INDUSTRIAL CATEGORY
NATIONWIDE
! INDUSTRIAL INFORMATION
1
1
!
! INDUSTRY
! NAME
} sasssssssssssssssssssssssss
{ALUMINUM FORMING
I BUTTERY MANUFACTURING
!COAL MINING
ICOIL COATING
{COPPER FORMING
i ELECTRICAL
{FOUNDRIES
! INORGANIC CHEMICALS
{IRON t STEEL
{LEATHER TANNING
{METAL FINISHING
{NONFERROUS METALS
{NONFERROUS METALS FORMING
!ORE MINING
iORGANICS/PISF - U
{PESTICIDES
{PETROLEUM REFINING
{PHARMACEUTICALS
{PLASTICS HOLDING t FORMING
{PORCELAIN ENAMELING
tNnVS-M
! PULP I PAPER
iTEITILES
IOIMER
i ••••!!• IlliaMTMM
NUMBER
OF PLANTS
42
IS
10,375
36
37
84
301
149
738
17
2,800
112
51
515
304
42
164
83
810
28
15,342
355
229
6,602
PROCESS
FUNS
(1000 6PD)
7,258
111
6,417,045
1,132
2,231
12,806
7,019
166,098
1,497,651
4,160
365,865
8.671
358
1,359,000
387,000
4,570
312,000
11,074
88,476
1,784
26,762,000
3,746,444
177,682
~~
! TOTAL SUSPENDED SOLIDS
1
: AVG
{CONCENTRATION
{ Ing/1)
12,000
12,000
31,222
12,000
12,000
12,000
3,365
43,924
10,859
56,000
17,800
2,750
8,405
8,451
102,563
—
26,100
107,000
4,866
12,000
32,485
28,445
49, 124
~~
TOTAL
LOADING
(Ibs/dl
727
11
1,672,004
113
223
1,282
197
60,883
135,470
1,944
54,348
199
IB
95,845
331,211
—
67,957
9,868
3,593
179
7,254,450
889,338
72,842
"
{ BIOCHEMICAL OXYGEN DEMAND
1
t
{ AV6
{CONCENTRATION
{ (ug/1)
~
—
—
—
—
—
—
—
—
33,800
—
—
—
—
57,720
—
13,500
83,000
3,527
—
33,433
17,327
22,439
~~
TOTAL
LOADING
Ubs/d)
—
—
—
—
—
—
—
—
—
1,173
—
—
—
—
186,397
—
35,150
7,670
2,604
—
7,466,130
541,732
33,273
~
{ PRIORITY ORGANIC POLLUTANTS
!
! AVG TTO
{ CONCENTRATION
! («g/l>
5
—
2
39
592
703
364
—
21
168
53
48
—
—
140
—
39
680
168
—
115
103
466
" »~
TOTAL TTO
LOADING
(Ibs/d)
0
—
133
0
11
75
21
—
262
6
163
3
—
—
453
—
103
63
124
—
25,720
3,355
691
- ~-~
! PRIORITY INORGANIC POLLUTANTS
1
{ AVG TTI
! CONCENTRATION
! (ug/1)
1,039
1,705
138
926
1,842
1,418
1,089
500
204
1,930
2,147
1,696
926
1,112
101
—
306
760
129
2,077
101
261
970
.
TOTAL TTI
LOADING
Ubs/d I
63
2
7,401
7
34
152
64
767
2,551
67
6,555
132
2
12,616
327
—
7%
70
95
31
22,557
8,166
1,438
_
TOTALSi
39,231
10,652,722
8,274,129
31,182
63.893
SOURCES Indmtry Status Sheet Reoort (ISS).
NOTE: ISS flows and concentrations are based on aoplicable BPT, BCT, BAT, and secondary treatment regulations.
NOTE: Information unavailable for other industrial categories at this time.
NOTE: TTO - TOTAL TOXIC OR6ANICS: TTI - TOTAL TOXIC INORGANICS
- - INFORMATION UNAVAILABLE FRON ISS OR DEVELOPMENT DOCUMENTS
»t - POTH plant flon and number information is fron the 19B4 Needs study.
Total priority pollutant loadings are average values of accliiiated and unacclimated median loading values obtained fro* The Domestic Sewage Study.
Total TSS and BOD loadings are from the 1964 Needs study.
tt - Based on ITD information (September 1986).
-------
TABLE 2
SUMMARY OF TOTAL POLLUTANT
BY INDUSTRIflL CATEGORY FOR INDI
NATIONWIDE
LOADINGS
RECT DISCHARGERS
INDUSTRIflL INFORMATION
INDUSTRY NUMBER
NAME OF PLANTS
ALUMINUM FORMING
BATTERY MANUFACTURING
COAL MINING
COIL COATING
COPPER FORMING
ELECTRICAL
FOUNDRIES
INORGANIC CHEMICALS
IRON 1 STEEL
LEATHER TANNING
METAL FINISHING
NONFERROUS METALS
NONFERROUS METALS FORMING
ORE MINING
ORGANICS/PISF - «
PESTICIDES
PETROLEUM REFINING
PHflRMACEUTICALS
PLASTICS MOLDING 1 FORMING
PORCELAIN ENAMELING
PULP 1 PAPER
TEXTILES
64
126
0
119
45
265
499
38
160
141
7,500
115
151
0
366
39
47
388
1,145
50
261
974
Bs=s=s=ss==
! TOTAL SUSPENDED SOLIDS ! BIOCHEMICAL OXYGEN DEMAND ! PRIORITY ORGANIC POLLUTANTS ! PRIORITY INORGANIC POLLUTANTS
PROCESS ! AVG TOTAL ! AVG TOTAL ! AVG TTO TOTAL TTO ! AVG TTI TOTAL TTI
FLOWS (CONCENTRATION LOADING {CONCENTRATION LOADING ! CONCENTRATION LOADING ! CONCENTRATION LOADING
(1000 6PD) ! (ug/1) llbs/d) !
-------
TABLE 3
SUMMARY OF REACHES
RtttlVlNti POINT SUURCE-I DIRECT I DISCHARGES
BY HYDROL06IC REGION
NATIONWIDE
:32 fUtSOAf, NOVEMBER 18, 1906
tGlOM
01
OZ
03
04
05
06
07
08
09
10
11
12
13
14
IS
16
17
18
TOTAL NUMBER
OF REACHES
400
1.014
1,641
750
1,751
356
1,275
497
89
699
8? 7
641
75
101
51
38
638
249
s=rr =2
11,310
TOTAL
MILES
4,897
15.513
26,989
13,037
23,564
4,569
22.047
10,817
2,330
11,289
16,106
12,083
2,005
1,470
1,175
794
6,795
4,319
=s===zs
179,799
NUMBER OF REACHES
INDUSTRIAL ONLY
131
272
519
165
702
140
134
78
11
109
119
74
12
42
8
5
193
102
SS = = 3
2,816
INDUSTRIAL
MILES ONLY
1,382
3,741
6,464
2,301
7,544
1,673
1,961
1.156
225
1,593
1,753
1,198
312
706
205
122
1,836
1,712
35.884
NUMBER OF REACHES
POTW ONLY
120
378
727
286
475
110
823
265
63
514
547
429
53
48
36
27
322
85
sss = =
5,308
POTW
MILES ONLY
1.280
5,227
10,170
4,555
6.971
1,206
14,224
5,956
1,676
8,291
10,967
8,010
1,475
629
805
543
3,417
1,589
S====3
66,991
NUMBER OF REACHES
INO. ft POTW
149
334
595
299
574
106
318
154
15
76
161
138
a
11
7
6
123
62
B33S3
3,186
INO. I POTW
MILES
2,235
6,545
10.354
6,181
9,049
1,690
5,863
3,706
429
1.405
3,366
2,675
217
136
165
129
1,541
1,017
8S3SSB
56,923
SOURCE: IFO and REACH FII E
MO'li;: Sum of FntritfS Hay Not Equal Totals Due to Round-offs.
Total Number of Reaches in U.S. is 68,000.
Total Mileage of Reaches in U.S. is 700,000.
-------
TABLE 4
SUMMARY OF TO1HS RECEIV1UO INDUSTRIAL DI3CMAR6C3
NATIONWIDE
14:22 TUESDAY, NOVEMBER 16, 1966
REGION
01
02
01
04
OS
06
07
oe
09
10
It
12
I)
14
IS
16
17
18
NUMBER OF
rows
175
147
496
272
191
at
190
a6
13
121
121
11*
11
7
S
*
69
67
aaaaa
2,705
NUMBER OF
REACHES
110
256
406
219
262
74
321
66
It
115
166
97
9
7
S
6
64
68
•*••*
2,227
TOTAL
MILES
1,616
4.006
6,088
4.091
4,989
1.034
5.8S7
1,505
376
1.968
2,149
2,162
319
57
94
125
763
1,247
Baazaa
38,486
TOTAL
FICUIMGOI
911
1,358
1.277
1,190
1,569
tot
t.492
207
25
608
412
677
67
II
65
71
439
1,517
sacrss
17.178
TOTAL MCEOS
INDUSTRIAL FLOHIMGOI
222
591
414
760
141
70
525
74
4
141
84
107
7
I
8
12
108
342
• «C£9
3.829
SUMMARY OP POTNS RECEIVING NO INDUSTRIAL DISCHARGES
NATIONWIDE
iSION
01
02
ei
04
05
06
07
08
09
10
II
12
11
14
IS
16
17
16
NUHHIR op
rams
24t
1,217
1,644
791
1.666
214
1.516
610
95
678
940
1.174
76
72
58
37
522
167
»aaa:x
12,401
NUMBER OP
REACHES
166
644
1,084
475
926
166
971
397
71
SIS
647
522
56
55
41
29
411
104
seas*
7,100
TOTAL
MILES
2.666
10,386
17,416
9,164
14,109
2.297
17.545
9.291
1,920
6,520
11.161
10.097
1.457
716
9't2
604
4.669
1,959
aSSSZaS
126, 9K2
TOTAL
FLOMIKSO)
662
2.694
1,411
6.995
32.112
99
564
262
46
317
115
1.081
IS
29
162
150
611
1.116
tsarss
48,901
TOTAL NEEDS
INDUSTRIAL FLOMMGDI
-------
Table 5
Sunmary of Projected Exceedances of Criteria or Toxic Effects Levels Along Stream
Reaches at Two Flow Conditions with Inudstrial Direct Dischargers and POTWs
MEAN STREAM FLOW
LOW STREAM FLOW
# Of
Reaches
68,000
Miles on
Those Reaches
700,000
TOTAL IN U.S.
INDUSTRIAL (Only) 1,185 14,002
Inorganic Exceedances (Only) 578 7,547
Organic Exceedances (Only) 1 20
Inorganic & Organic Exceedances 45 509
BOD Exceedances 27 291
POTW (Only) 6,781 113,534
Inorganic Exceedances (Only) 2,617 45,330
Organic Exceeuances (only) 0 0
Inorganic & Organic Exceedances 1,135 21,239
BOD Exceedances 2,225 39,920
INDUSTRIAL & POTW 1,347 22,777
Inorganic Exceedances (Only) 668 11,773
Organic Exceedances (Only) 0 0
Inorganic & Organic Exceedances 220 3,933
BOD Exceedances 435 7,560
TOTALS
Reaches Analyzed 9,313 150,310
Inorganic Exceedances (Only) 3,863 64,650
Organic Exceedances (Only) 1 20
Inorganic & Organic Exceedances 1,400 25,681
BOD Exceedances 2,687 47,771
of Reaches
68,000
1,185
131
0
6
2
6,781
598
0
38
157
1,347
268
0
11
46
9,313
997
0
55
205
Miles on
Those Reaches
700,000
14,002
1,907
0
29
1
113,534
9,436
0
649
2,522
22,777
4,637
0
186
712
150,310
15,980
0
864
3,235
Pollutants examined with criteria or toxic effects levels
Inorganics Cadmiun (1.1 ug/1) , Copper (12 ug/1), Mercury (.012 ug/1),
Lead (3.2 ug/1), Zinc (47 ug/1) & Cjanide (5.2 ug/1)
Organics Bis(2-ethylhexyl) phthalate (3 ug/1) , pentachloropbcnol (PCPM3.2 ug/1)
BOD 10 mg/1
Number of Facilities in Analisis 20,993
-------
Attachment A
Introduction - The Perceived Problem
Roughly 65,000 permitted point sources (PCS) discharge
approximately 6.4 trillion gallons of effluent (Renfroe, 1978)
into the nation's surface waters every year even though many of
the aguatic systems that receive these process wastes afford
little dilution (40-60% of the stream reaches provide less than
10:1 dilution at low flow). And regulated discharges are not
the only concern. There is mounting evidence that impacts
caused by uncontrolled point sources (either non-compliant or
illegal discharges) are as important as impacts caused by normal
variations in effluent quality and stream flow (TSD, 1985).
Combined sewer overflows (CSO's) also sporatically discharge
large quantities of BOD, solids, and toxics that may severely
impact certain areas.
A. Pollutants Discharged from Point Sources and Their General
Effects
Pollutants of principal ecological concern can be grouped
into three broad categories: oxygen-demanding materials
(primarily organic nutrients) substances toxic to aquatic
life, and other chemical/physical water physical water
quality parameters (e.g., TSS).
1. Nutrients - Effects are typically characterized in
terms of BOD, P, and N loading.
Point sources, particularly POTWs, discharge organic
and inorganic nutrients than can disrupt the natural
trophic dynamics of an aquatic system. This metabolic
imbalance will typically cause a shift in community
structure from a relatively diverse biotic assemblage
characterized by "clean water" species to one dominated
by less desirable, "pollution tolerant" forms. In the
extreme case, biochemical breakdown of excess organic
material (either introduced or created from inorganic
nutrients through biological production) can reduce
dissolved oxygen to levels that are actually lethal to
higher aquatic organisms. Because natural biochemical
oxidation of organic nutrients is a relatively slow
process, the various impacts of pollution are typically
expressed at considerable distance from the point of discharge.
2. Toxic substances - Effects can be characterized by
exceedance of criteria derived from an array of single-
species bioassay tests.
Toxicants can affect aquatic communities by differentially
reducing or eliminating certain species populations.
Overall productivity is inevitably reduced and
alterations in competitive relationships are likely to
cause shifts in community structure. The actual magnitude
-------
and direction of such structural change is very
difficult to predict because of the large number of
toxic agents, the complexity of the mixtures actually
discharged, and the wide variation in sensitivities
among species. Toxic impacts are generally most severe
in the immediate vicinity of discharge where concentrations
are highest. Certain persistent toxicants may be
transported considerable distances however before they
are deposited and bioconcentrated into the food chain.
3. Conventional chemical/physical parameters - solids,
pH, temperature.
Suspended and settleable solids can affect aquatic
life directly through mechanical, abrasive action
(e.g., clogging gills, smothering eggs, and larvae) or
indirectly by either altering habitats, (e.g. blanketing
bottom substrates, spawing gravels etc.) or influencing
water quality (reducing light penetration, sorbing
cations, anions, organic compounds). Hydrogen ion
concentrations (pH) also profoundly affect the physiology
of aquatic organisms and the chemical/physical
suitability of their environment; ambient pH values
below 6.5 and above 9.0 are considered undesirable in
freshwater (Quality Criteria for Water, 1986). Finally,
temperature, one of the most important parameters
affecting animal physiology and water chemistry, can
cause ecological impacts when normal ambient levels
are either chronically altered or abruptly changed.
B. Ecosystems Affected
1. Marine Ecosystems - Because they are typically
better buffered than freshwater systems (more
dilution, greater hardness), marine systems are
usually more resistant to stress. However, they
are often slow to recover once damaged.
a. Deep ocean - By virtue of its capacity to
dilute foreign matter to inconsequential
concentrations, the risk of damage from point
source discharges was considered negligible.
b. Coastal waters - Resistance to impact is
relatively great due to high dilution and
intense physical mixing. Biological communities
of open coastlines are typically limited by
organic nutrients; they can be drastically
affected by any appreciable sewage inputs.
c. Estuaries - Geographically more confined and
enriched than open ocean or coastal zones,
estuaries are biologically far more productive
(per unit area). Many of the nation's largest
-------
population centers are located near the most
important estuariesf thus threatening them
with high concentrations of municipal and
industrial wastes. Large POTW discharges may
be located in such areas.
d. Tidal Wetlands - Wetlands function as filters
of inorganic and organic material and as such
serve to buffer adjacent aquatic systems.
They are dominated by higher plant forms which
provide both physical structure and functional
stability. Because of the resistance of these
higher plants to most toxics and excess
nutrients, wetland systems are comparatively
tolerant of chemical stress. But if the
physical integrity is damaged (e.g., toxic
contamination of the sediments or destruction
of the dominant macrophytes) the system may
never recover. Like estuaries/ tidal wetlands
are commonly located near population centers
and are frequently impacted.
2. Freshwater Ecosytems - These systems can be broadly
categorized as either lentic systems, standing waters
such as lakes and wetlands, or lotic systems, flowing
rivers and streams. "[Lakes]...are clearly less
suitable repositories for effluents than are rivers
which carry the offending matter away." (Hynes, 1971).
a. Cold water streams - A large proportion of the
nation's point source discharges are located on
these low order streams. They are classically
shallow, fast flowing, well oxygenated, and should
support highly desirable sport fisheries. They
are characterized by cobble/gravel riffles and
runs interspersed with occasional pool areas.
Biological communities are adapted to and limited
by the slow release of nutrients from allochthonous
organic matter i.e., gradual decomposition of
resistant forest materials washed into the streams.
These systems are likely to suffer major alterations
in community structure and function when subjected
to organic enrichment and/or DO depletion.
Furthermore, these low-volume systems typically
afford little dilution and are thus susceptible to
impact from toxic as well as organic loadings.
High current velocities and relatively inert bottom
substrates, however, help prevent build up of
persistent contaminants, thus promoting rapid/recovery
from toxic stress. Biological assemblages have many
-------
r-selected species which can quickly repopulate
defaunated areas and reestablish stable communities.
Warm water streams - These streams (rivers) occur
at lower altitudes/ have a lesser slope, a sluggish
flow, and bottom substrates composed of fine silts,
muds, and detritus. They generally have a much
larger volume then cold water streams and thus
greater assimilative capacity for discharged
wastes. The biological communities are adapted to
higher temperatures, lower DO levels, and greater
organic loadings than cold water biota.
A large proportion of the nation's population and
much of its industrial development has occurred
along these waterways and they have always been
subjected to massive inputs of nutrients and
toxics. They are also more susceptible than fast-
flowing streams to chronic contamination from
sedimenting, persistent pollutants.
Lakes - Lakes vary tremendously in their size,
origins, geology, and natural water quality. On a
geologic time scale they are comparatively
transitory, naturally becoming more "polluted" as
nutrients leached from the surrounding drainage
enter the lake. Nutrients are converted to organic
material within the lake itself and deposited in
bottom sediments. Eventually (>25,000 years), the
lake basin actually fills with organic material
and is transformed first to a wetland (bog) and
finally to a terrestrial system.
Input of significant amounts of organic nutrients
greatly accelerates the processes of lake
eutrophication and destruction. Furthermore,
lakes are particularly vulnerable to impacts from
persistent toxicants because slow turnover rates
cause them to act as despositional sinks for these
pollutants.
Freshwater wetlands - These systems typically
occur as marshes or swamps along high order streams
and rivers where low relief provides a broad flood
plain. Less frequently, wetlands represent the
final stages of lake succession. Like tidal
wetlands, these systems function as silt and
nutrient filters, buffering water quality in the
river while accomodating excess flow during flood
periods. As transition systems, they are subject
to inputs from both aquatic and terrestrial sources,
are relatively resistant to stress, but are slow
to recover particularly from physical alteration.
-------
FCHRISK NPS Summary
The major ecological risk from nonpoint sources is erosion. The primary
pollutant is sediment which erodes from the surface of the land and is trans-
ported to streams, reservoirs, estuaries, and eventually to the ocean by the
runoff from precipitation. Cropland is the chief source of sediment on a total
mass basis. The latest figures indicate this source accounts for 38* of the
total load annually. Pasture and range land contributes 25% while forests' share
is 5%. Construction contributes 4% and mining 1%. Natural background accounts
25%.
These sources contribute several pollutants in addition to sediment.
Agriculture contributes excess nutrients, pesticides, and bacteria. Mining,
runoff can be acidic, and from urban runoff we can expect heavy metals, and
other toxic pollutants in addition to some sediment. Organic wastes are trans-
ported much the same way as sediment and have essentially the same adverse ef-
fects as organic wastes of domestic and industrial orgin. Thermal pollution is
a concern from silviculture where removal of tree cover along stream banks
exposes the water to the suns' rays. While the contribution of sediment from
silviculture is low by comparision, it has a deleterious effect on
spawning beds in upstream reaches. Fine silt can and does smother these beds
rendering them useless. Other problems from excess sediment are silting of
reservoirs, clogging of shipping channels, and the deposition of toxic poll-
utants which are attached to the sediments.
-------
Problem 111
Nonpoint Sources and In-Place Pollutants
The work group modified the original problem definitions
to fold a problem of aquatic in-place (sediment) pollutants into
the problem of nonpoint sources. Because sediment contamination
may result from either point or nonpoint sources, and is different
in nature than a nonpoint source, it is simpler to discuss the
two parts of problem ill separately, as done in the following
papers.
-------
Narrative Description
Nonpoint Sources
To categorize nonpoint sources is not easy. As there are many. What
will be discussed in the paper is a set of sources, generally accepted by
those now directly involved in its control. This list is as follows: Agricul-
ture, Silviculture, Construction, Urban, Resource Extraction, Hydromodification.
It should be clear from this list that nonpoint sources occur everywhere. This
is as it should be, for it rains everywhere and rain and runoff water are mostly
responsible for the generation and transport of nonpoint source pollution to
water bodies.
The land surface of the U.S. is about 2.2 billion acres these acres can be
divided up by land use. In this way we may get a little perspective on the real
extent of some of these rather large sources. About 500 million acres are relat-
ed to agriculture, about 22 per cent of the U.S. then is devoted to this source.
The nation's forests account for 33 per cent of the U.S. One can readily see the
major sources. Urban for example covers 7 per cent of the land area, however,
the populations are quite dense in comparison.
-------
AGRICULTURE
The impact of agriculture on the nation's water resources is significant.
Farmland in grass, pasture, and cropland plus farmsteads and roads total over
950 million acres of land area in the United States, and is scattered across
the face of the land, intimately connecting with nearly all of the major water
sources. Cropland represents about 413 million acres of farmland, pastureland
accounts for an additional 133 million acres.
The major uses of water include industrial use, irrigation, public water
supplies, navigation, recreation, and rural domestic uses. The quantity of
water used for irrigation ranks second only to that for industrial use. Of
the estimated 339 billion gallons of water consumed daily in the United States
more than 35% is used for irrigation. The impact of the use of water for
irrigation is limited mostly to the 17 western states where about 35 million
acres of the total 39 million acres or irrigated land are situated.
The trend in agriculture is to employ modern technologies at ever
increasing levels of complexity involving the use of fertilizers, pesticides,
irrigation systems, and contained animal feedlots. A consequence of this trend
will be the increased potential for water pollution both in the surface water
and in the groundwater. Protecting water quality will become a major concern
for agriculture.
Sources of Pollution from Agriculture
The pollutants resulting from agricultural discharges include sediments,
salt loads, nutrients, pesticides, organic loads, and pathogens. Sediment
resulting from soil erosion is regarded as the largest pollutant that affects
water quality. Agricultural lands, particularly cropland, are large contribu-
tors of sediment. Holeman estimated the total erosion rate per year for the
contiguous United States to be over 4 billion tons, of what about 2 billion
tons washes into streams and 1 billion ton reaches tide waters. The national
conservation needs inventory of the Soil Conservation Service estimated in 1971
that the total sediment yield from cropland per year was more than 1 billion ton.
Thus, cropland is responsible for about 50% of the total sediment yield in
inland waterways. Only a fourth of the total yield travels to the ocean.
Sediment also carries with it significant quantities of plant nutrients, pesti-
cides, organic and inorganic matter, pathogens, and other water pollutants.
About 2 billion tons of livestock wastes are produced annually in the
United States. These fertilizers contain roughly 20% nitrogen, 5.2% phosphorus,
and 8.8% potassium. Farmers use about 75% of the fertilizer consumed in the
United States. The composition of plant nutrients in commercial fertilizers
applied in different states varies considerably. For example, in Nebraska,
the composition of commercial fertilizers consumed during 1970 averaged about
40% nitrogen, 5% phosphorus, and 3% potassium. For Iowa, these values were
approximately 27% nitrogen, 7% phosphorus, and 11% potassium.
Some of these nutrients are transported, together with naturally occurring
nutrient elements, to surface and groundwaters.
-------
-2-
Irrigated agriculture involves leaching and transport of dissolved minerals
in soils, and flushing the unwanted salts from the soil. About 60% of irrigation
water is lost by evapotranspiration, while the remainder is returned by surface
runoff and subsurface flow to surface waters and to groundwater storage. Ihe
return flows carry large quantities of minerals and degrade the water quality
of the receiving streams.
Pesticides are designed to be lethal to target organisms, and many are toxic
to nontarget organisms. Four major categories are important in agriculture:
insecticides, fungicides, herbicides, and rodenticides. Our records show
660 million pounds of pesticides applied in the United States annually, about
70% was for farm use and the remaining 30% for public and governmental use.
The threat from pesticides is pritarily due to their persistence in the
aquatic environment, where fish and other food chain organisms accumulate
pesticides and their metabolites or degradation products. This phenomenon of
biological magnification appears to be especially significant with the fat-
soluble pesticides.
Organic loads from agricultural activities include rural wastewaters,
animal wastes, crop residues, and food processing wastes. When these substances
are carried to a water body, they exert a high biochemical oxygen demand (BOD).
Agriculture wastes are a source of pathogens. Diseases may be transmitted
through soil, water, or air when these wastes come in contact with plants and
animals. Agricultural losses caused by infectious agents of livestock and
poultry have been substantial. Wadleigh has summarized the cases of diseases
transmitted by infectious agents and allergens affecting plants and animals
from agricultural wastes.
-------
Silviculture
Over one-third of the U.S. is covered with forests. Approximately 67%
of the forests are classified as commercial forests, totaling 500 million
acres, of which approximately 67 million acres are in private industrial owner-
ship, 100 million acres are in public ownership, and the rest in private, non-
industrial ownerships. Depending on natural and land use characteristics, these
lands may produce substantial quantities of pollutants to surface and under-
ground waters.
An established, well managed forest can be remarkably resistant to
emission of pollutants to the aquatic environment. Incident rainfall is
deprived of most of its erosive force by the tree cover, and rates of infiltra-
tion through ground cover and into subsurface soils are given often high enough
that intense rainfall can be accommodated without runoff and the accompanying
cary-off of silt by erosion. Such a forest has the attributes popularly decreed
to be necessary and desirable, as well as technically and economically sound.
Many forests do indeed possess such attributes, and are at the same time useful,
productive entities. Productivity can be maintained over the long term with
assistance from man, which necessarily includes harvest of trees. A silvicul-
tural cycle includes a relatively long period of growth which can be essentially
free of pollutional output, and a relatively short period of harvest and refore-
station, which, as a result of disturbance, can be a tine of high pDllutional
output.
The principal aspect of silviculture we are concerned with here is timber
harvesting. The nations' forests are basically the nations' watersheds, where
water first begins its journey to oceans. Water in the forests is usually of
high quality ami risk is small. Sediment and nutrients can be a problem from
harvesting if it is done improperly. One aspect that has received attention
in the past four or five years, is the resultant destruction of of fish habi-
tat fron sediment deposition. Fine-grained Sediment, settles in gravels of up-
stream reaches, below where timber harvesting is being practiced, usually in
the mountain where coldwater fish and annadramous fish spawn. The result is
reduction or destruction of in spawing sites.
Disturbances to the forest ccme from nature as well as from man. Disease,
insects, windstorms, droughts, and fires can devastate a forest, and degrade it
to a polluting condition. Silvicultural activities, which are generally con-
cerned with timber production, with prevention of natural devastation, and with
restoration to a state of health and productivity, consist of harvesting, refore-
station, growth promotion, disease prevention, fire fighting and fire prevention.
The principal sources of pollution from forests thus are disturbances caused
by man. The major types of pollutants from forestlands are sediment, organic
matter, applied forest chemicals (pesticides, fertilizers, fire retardants),
plant nutrients, and pathogens. Thermal effects on streams from solar radiation
associated with the reduction of shade from streamside vegetation are, in some
cases, pollutional.
-------
Urban
We probably know more about this source than all of the others. Runoff
from urban areas is a result of rainfall washing the streets, steel mills,
parking lots, etc. The effects of the stress agents are primarily to violate
water quality criteria. This is the most frequently encountered problem. In
certain causes the runoff will necessitate the closing of shell fish beds due
to the high bacteria counts in urban runoff. Copper is a stress aqent that is
lethal to lower forms of aquatic life at very low concentrations. As a result
our criteria is quite low and copper is ubiquitous in urban runoff and violations
occur most of the time. There is no evidence, however, of fish (large fish)
being killed from separate storm sewer discharges.
One problem froti separate storm sev/ers is that the are not always entirely
separate. There is a wide-spread unspoken problem with illegal connections.
These are sanitary connections, industrial connections, and comerical connec-
tions, that for one reason or another have been connected to the storm drains
instead of to the sanitary lines. The result is continous discharge of untreat-
ed waste. The cost to correct this problem is so high that it will probably be
the last thing done to clean up the environment. Example of cities that have
this problem are Baltimore, New Orleans, and Fort Worth. There are many others.
-------
Construction
The accelerated rise in the U.S. population through the year 2000 will
require the daily development of about 4,000 acres of land to accommodate
the expanded requirements for new housing and related services, transportation,
utilities, communications, and sewer and wastewater treatment networks—all of
which are construction oriented. Land areas sufficient to accomodate these new
operations must be found without limiting those land and water resources needed
to produce the food supplies essential to the sustenance of increased numbers
of plants, animals, and man. At the present time, more than two-thirds of the
U.S. population is located in urbanized areas covering 7% of the land area.
This source includes urban, rural, and other areas of construction. The
primary concern is site runoff and the resulting excess sediment loss. This
is another example of a land disturbance similar to silviculture and agricul-
ture. The difference is the length of time associated with the land exposed to
the elements. The loads are unusually high but do not last long, causing a
short term insult to the enivrorwent compared to ag or silvicultural sources.
Emphasis must be placed on the fact that environmental impacts of
construction must be assessed on a site-by-site basis. Construction activity
refers to major jobs, characterized in part as heavy (as in damsites and other
excavations), highway, housing developments, transmission and pipelines, dredg-
ing, and demolition operations—whether done in an urban or rural environment.
Construction practice refers to timber clearing, grubbing, and topsoil stripping;
rough grading, concrete, asphalt and other facility operations; waste disposal;
soil stabilization, fertilization, and revegetation; traffic control; pest con-
trol, and site restoration following construction. This term includes all job
operations that generate various types of water jpollutants by spillage, ero-
sion, sedimentation, and stormwate runoff.
-------
Hydromodification
This source involves channelization, dam construction, flood control, and
other water detention and/or drainage-related structures or operations. This
work is generally site specific and sometimes short term in nature, however, in
the use of channel dredging it is normally periodic in nature. As cities grow,
and highways grow rivers, in particular are affected by the construction of
bridge piers and abutments. There has been much channelization for drainage
control in urban areas and for agriculture. The primary effect is habitat
alteration which often causes serious problems.
In addition, when flow regimes of streams are altered, such as in dam
building, water flow regimes are changed remarkably which results in sedimenta-
tion problems in the reservoirs and d^wnstreanu Hydrt_nod differs from construc-
tion as it relates only to water bodies.
-------
Resource Extraction
For purpose of this assessment, energy resources from extraction were not
considered as this is being covered under a separate element. Mining activi-
ties in the U.S. have affected approximately 20 million acres of land accord-
ing to estimates by the U.S. Department of the Interior. By the year 2000
the Department estimates that 30 milion acres will be affected by mining
operations.
While the land area presently affected by mining represents only about
1 per cent of the U.S., the effects of mining upon water quality and quanity
are spread over large regions. The effects of mining include pollution of water
supplies with acid mine drainage, heavy metals, toxic substances, and sedLnent.
Nonpoint source pollution from mining operations arises because the
hydrology of surface and subsurface waters is altered when the earths' crust is
disturbed to gain access to minerals and minerals are exposed to oxidation. The
quality of this water very often deteriorates, and the quantity is redistributed
as a result of the mining operations. Water quality deteriorates when water sup-
plies are contaminated with soluble products present in or generated from mining
wastes. Water quantity is affected because natural drainage patterns for surface
and subsurface waters are altered.
-------
Completeness
of
Information
Agriculture
Silviculture
Urban
Resource Extractio
Construction
Hydromodification
Water
Quality
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Completeness
There is much information on nonpoint sources however, it is not all of
the useful type. There are whole areas where there is a real need for infor-
mation. There are areas of need we will never fill.
The different types of information are Tiyriad and as such are probably best
discussed in tabular form. The following chart lists the various nonpoint source
categories and the different types of information that we feel we need to control
nonpoint source pollution.
-------
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from those streams and lakes assessed. Many miles and lake acres were not assessed.
*** Note: Numbers from EPA-A30/9-73-01A-1073, "METHODS FOR IDENTIFYING AND EVALUATING NONPOINT SOURCES
OF POLLUTANTS".
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-------
URBAN
SOURCES :
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sewer discharge
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-------
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-------
Exposure
The exposure of receiving water to nonpoint source pollution is a direct
result of rainfall and the corresponding runoff. Therefore the exposures
are dependent on the runoff. This makes it easy to understand that exposures
of nonpoint source are of short duration, on the order of hours, and infrequent,
about once every three days. We have the necessary data on rainfall to determine
the long term frequency and duration as well as volume of events at 6000 sites
nationwide.
To date, only urban runoff has been analyzed using the rainfall, runoff
statistics. For other sources we must rely on substitute information. The
proceeding section, of this report, on sources lists areal extent and by use
of check marks indicate, to some degree, the exposure of source such as
agriculture, construction, hydromod, etc.
Because of relatively short duration of storm events, there is a lack
of sufficient time for the washed pollutants to do serious damage. In
addition, the events are infrequent enough so as to let the effected stream
recover before it rains again. While this is true for urban runoff, it is
not clear that this also applies to agriculture.
For as to be better able to assess exposure resulting from periodic storm
events, we will need new methodologies, more data on close-response for more
organisms. We have made an initial attempt at this for urban runoff. We found
that current water quality criteria was not sufficient for our purpose. We
developed our own and were thus able to develop a better understanding of the
runoff/receiving water effect phenomenon.
The following graph was developed from extensive data collection and
analysis and the use of special water quality criteria developed as part of the
NURP program. The graph allows us to present, on sheets of paper, the effects
of urban runoff in terms of frequency of violation of a criteria, frequency of
biological effects, and how much control may be needed to meet a given criteria.
-------
KtA.ilVJ.Nlj
General
A number of individual NURP projects examined the site-specific impacts of
urtow runoff on water quality for a variety of beneficial uses and receivmg
wacer types. These results provide important information on the extent to
which urban runoff constitutes a "problem" as well as "ground truth" measure-
ments against which more generalized techniques can be compared. Method-
ologies employed in these local studies vary and are described in the
individual project reports. Relevant site-specific project results are cited
in Chapter 9.
Receiving water impact analyses cannot be readily generalized because there
is a high degree of site-specificity to the important factors. The type of
beneficial use dictates the pollutants which a're of principal concern; the
type of water body (e.g., stream, lake, estuary) determines how receiving
water quality responds to loads; and physical characteristics (e.g., size,
geometry, flows) have a major influence on the magnitude of response to a
particular load.
Despite the inherent limitations of a set of generalized receiving water im-
pact analyses, a screening level analysis was considered a necessary element
for a nationwide assessment of the general significance of urban runoff in
terms of water quality problems, especially adverse effects on beneficial
uses. Accordingly, a set of analysis methodologies were adopted and utilized
as screening techniques for characterizing water quality effects of urban
runoff loads on receiving water bodies. A key requirement was to delineate
the severity of water quality problems by quantifying the magnitude, and in
the case of intermittent loads, the frequency of occurrence of water quality
impacts of significance. These procedures are identified and described
briefly below. Significant technical aspects are detailed further in the
supplementary NURP report which addresses the receiving water impact analysis
methodology.
It was not possible to perform a "National Assessment" in the usual sense of
the term. NURP has determined that it is not realistic (if the basis is
effect on beneficial use of a water body) to estimate the total number of
water quality problem situations in the nation which result from urban storm-
water runoff or the cost of control which would ultimately result. The
available analysis methods do permit an assessment of a different kind. NURP
applied the analysis procedures as a screening type analysis to define the
conditions under which problems of different types are likely or unlikely to
occur. From the results of these screening analyses, NURP has drawn infer-
ences and made general statements (Chapters 7 and 9) on the significance of
urban runoff. Where it has been possible or practical to do so, these
general screening analyses were applied to local situations which exist
within certain of the individual NURP projects. Comparisons were made
between specific water quality effects or broader conclusions relative to
problems derived from both local analysis and general screening methods.
Time Scales of Water Quality Impacts
There are three types of water quality impacts associated with urban runoff.
The first type is characterized by rapid, short-term changes in water quality
during and shortly after storm events. Examples of this water quality impact
include periodic dissolved oxygen depressions due to oxidation of contami-
nants, or short-term increases in the receiving water concentrations of one
-------
or more toxic contaminants. These short-term effects are believed to be an
important concern and were the prime focus of the NURP analysis.
Long-term water quality impacts, on the other hand, may be caused by contami-
nants associated with suspended solids that settle in receiving waters and by
nutrients which enter receiving water systems with long retention times. In
both instances, long-term water quality impacts are caused by increased resi-
dence times of pollutants in receiving waters. Other examples of the
long-term water quality impacts include depressed dissolved oxygen caused by
the oxidation of organics in bottom sediments, biological accumulation of
toxics as a result of up-take by organisms in the food chain, and increased
lake entrophication as a result of the recycling of nutrients contributed by
urban runoff discharges. The long-term water quality impacts of urban runoff
are manifested during critical periods normally considered in point source
pollution studies, such as summer, low stream flow conditions, and/or during
sensitive life cycle stages of organisms. Since long-term water quality
impacts occur during normal critical periods, it is necessary to distinguish
between the relative contribution of urban runoff and the contribution from
other sources, such as treatment plant discharges and other nonpoint sources.
A site-specific analysis is required to determine the impact of various types
of pollutants during critical periodsf and this aspect of urban runoff
effects was not addressed in detail in NURP.
A third type of receiving water impact is related to the quantity or physical
aspects of flow and includes short-term water quality effects caused by scour
and resuspension of pollutants previously deposited in the sediments. This
category of impact was not addressed by NURP, in general, although one
project provides some information.
As indicated previously, the first type of change in water quality associated
with discharges from urban runoff is characterized by short-term degradation
during and shortly after storm events. The rainfall process is highly vari-
able in both time and space. The intensity of rainfall at a location can
vary from minute to minute and from location to location. Phenomena which
are driven by rainfall such as urban runoff and associated pollutant loadings
are at least as variable. Short term measurements, on a time scale of
minutes, to define rainfall, the runoff flow hydrograph, and concentrations
of contaminants (pollutographs) feasibly can be taken at only a rather
limited number of locations. These measurements have usually been employed
in an attempt to refine or calibrate calculation procedures for estimating
runoff flows and loads. Most urban areas contain a network of drainage
systems which collect and discharge urban runoff into one or more receiving
water bodies. Since the rainfall, runoff, and pollutant loads vary in both
time and space, it is impossible to determine by calculation or measurement
the very short time scale (minute-to-minute) changes in water quality of a
receiving water and assign the changes to specific sources of runoff.
Although very short duration exposures (on the order of minutes) to very high
concentrations of toxics can produce environmental damage (mortality or sub-
lethal effects) to aquatic organisms, it is likely that exposures on the
order of hours have the highest possibility of causing adverse environmental
impacts. This results, in part, from the smoothing obtained by mixing
numerous sources which have high frequency (short-term) variability.
-------
In view of the above discussion, the time scale used by NURP for analysis of
short-term receiving water impacts is the rainfall event time scale which is
on the order of hours. To represent the average concentration of pollutants
in urban runoff produced during such an event, NURP used the event mean
concentration.
Criteria/Standards and Beneficial Use Effects
As discussed in previous chapters, three definitions have been adopted to
assess receiving water problems associated with urban runoff; (1) impairment
or denial of beneficial use, (2) violation of numerical criteria/standards,
and (3) local perception of a problem. The procedures and methods employed
in the NURP assessment focus on the first two problem definitions. A frame-
work for identifying target receiving water concentrations associated with
the criteria standards and beneficial use problems are provided below. The
third problem type, local perception of a problem and degree of concern
canr.ct be addressed! by these quantitative procedures.
The analysis methods employed make it possible to project water quality ef-
fects caused by intermittent, short-term urban runoff discharges. Where
appropriate, these effects are expressed in terms of the frequency at which a
pollutant concentration in the water body is equalled or exceeded. However,
if the basis for determining the significance of such water quality impacts
(and hence the need for control) is taken to be the effect such receiving
water concentrations have on the impairment or denial of a specific bene-
ficial use, then it is necessary to go one step further. A basis is required
for judging the degree to which a particular water quality impact constitutes
an impairment of a beneficial use. With intermittent pollutant discharges,
effects are variable and are best expressed in terms of a probability distri-
bution from which estimates can be made of the frequency with which effects
of various magnitude occur.
There is a rather broad consensus that existing water quality criteria, and
water uses based on such criteria, are most relevant when considered in terms
of continuous exposures (ambient conditions). Even where continuous dis-
charges are involved, there has been discussion and debate as to whether a
particular criterion should be interpreted as some appropriate "average" con-
dition or a "never-to-exceed" limit. The basic issue is whether the more
liberal interpretation will provide acceptable protection to the beneficial
use for which the criterion in question has been developed. The only reason
such distinctions become an issue is because the practical feasibility or
relative economics, or both, are sufficiently different that one is encour-
aged to question whether the more restrictive interpretation is overly (or
even excessively) conservative in terms of providing protection for the as-
sociated beneficial use.
The issue (i.e., whether traditional ambient criteria are excessively con-
servative measures of conditions which provide reasonable assurances of
protection for a beneficial use when exceeded only intermittently) is par-
ticularly appropriate in the case of urban storm runoff. Analysis of rain-
fall records for a wide distribution of locations in the nation indicates
that, even in the wetter parts of the country, urban runoff events occur only
-------
about 10 percent, of the time. There are regional and seasonal differences,
but typical "values for annual average storm characteristics in the eastern
half of the United States are:
Storm Duration
Interval Between
Storm Mid-Points
Average
(Hours)
6
80
Median
(Hours)
4.5
60
90th Percentile
(Hours)
15
200
These estimates are based on results from an analysis of long-term rainfall
records for 40 cities throughout the country. Median and 90th percentile
values are derived from data mean and variance based on a gamma distribution,
which has been shown to characterize the underlying distribution of storm
event parameters quite well.
In the semi-arid regions of the western half of the country, average storm
durations tend to be comparable to the above, but average intervals between
successive storms increase substantially (two to four fold) and ore highly
seasonal. With urban storm runoff, therefore, one is dealing with pollutant
discharges which occur over a period of a few hours every several days or
more or after long dry periods. In advective rivers and streams, the water
mass influenced by urban runoff tends to move downstream in relatively dis-
crete pulses. Because of the variability in the magnitude of the pollutant
loads from different storm events, only a small percentage of these pulses
have high pollutant concentrations.
There are currently no formal "wet weather" criteria and, thus, no generally
accepted way intermittent exposures having time scale characteristics typical
of urban runoff can be related to use impairment. In the belief that it
would be inappropriate to ignore such considerations in a general evaluation
of urban runoff, NURP has developed estimates for concentration levels which
result in adverse impacts on beneficial use when exposures occur intermit-
tently at intervals/durations typical of urban runoff. These "effects
levels" were used to interpret the significance of the variable, intermittent
water quality impacts of urban runoff. It should be understood that these
effects levels do not represent any formal position taken by EPA, but are
simply the most reasonable yardsticks available to meet the immediate needs
of the evaluation of urban runoff. As used in the screening analysis proce-
dures, alternative values for "effects levels" may be readily substituted
when either more accurate estimates can be made, or more (or less) conserva-
tive approaches are indicated in view of the importance of a particular water
body or beneficial use.
Table 5-1 summarizes information on water quality criteria for a number of
contaminants routinely found in urban storm runoff. The data presented
include:
- Water quality criteria for substances on EPA's priority pollut-
ant list (45 FR No. 79318, 11/28/80). These criteria provide
-------
TABLE 5-1. SUMMARY OF RECEIVING WATER TARGET CONCENTRATIONS USED IN
SCREENING ANALYSIS - TOXIC SUBSTANCES
(ALL CONCENTRATIONS IN MICROGRAMS/LITER,
Contaminant
Copper
Zinc
Lead
throw («3)
Chrome (««)
Cadmium
Nickel
Hater
Hardness
•9/1
(as Ca COj)
50
100
200
JOO
SO
too
200
300
SO
100
200
300
SO
100
300
SO
100
300
SO
100
300
Freshwater
Aquatic Life
24 Hour
S.6
s.e
S.6
S.6
47
47
47
47
0.7S
3.8
12. 5
SO.O
<««)
(C)
0.29
0.01
0.02
0.08
56
96
220
Max
12
22
42
62
180
321
S20
800
74
172
400
660
2,200
4,700
15 ,000
21.0
1.5
3.0
9.6
1.090
1.800
4.250
Saltwater
Aquatic life
24 Hour
4.0
4.0
4.0
4.0
58
58
SB
58
(25)
1C)
M.P.
18
4.S
7.1
Max
23
23
23
23
I/O
170
170
I/O
(670)
(A)
(10,300)
(A)
1260
S9.0
140.0
Human
Ingeslton
(1)
HP
M>
SO.O
170.00
SO.O
10
13.4
Estimated Effect Level
For Intermittent
Exposure
Thresh-
hold
20
3$
80
115
380
680
1.200
1.700
ISO
360
850
1.400
8.650
3
6.6
20
Significant
Mortality
SO - 90
90-150
1?0 - 350
26S - 500
870 - 3,200
1,550 - 4.500
2,750 - 8.000
3.850 - 11,000
350 - 3.200
820 • 7.500
1.950 - 17.850
3.100 - 29.000
7 - 160
IS - 350
4$ - 1,070
MOTES:
HP * No criteria proposed.
Sow tonic criteria are related to Total Hardness of receiving water. Mnere this applies, several values are shown. Other
values may be calculated fro* equations presented in EPA's Criteria DocuMiit (Federal Register. 45,231. November 28. 1980).
Mhere a single value is shown, water hardness does not influence toxic criteria.
Concentration valves shown within parentheses ( ) art not fomal criteria values. The> reflect cither chronic (C) or acute
(A) tux icily concentrations which the EPA toxic criteria document indicated have been observed. Values of this type were
reported where the data bask was insufficient (according to the formally adopted guidelines wMch wuie used 1n developing the
criteria) for EPA to develop 24 hour and Max values.
Mote (1): The "Hunan Ingestton* criteria developed by the EPA Toxic Criteria documents are indicated to relate to ancient
receiving water quality. The Drinking Water Criteria relate to finished water quality at the point ot delivery for
consumption.
Estimated Effects levels reflect estimates of the concentration levels which would Impair beneficial uses under the kind ol
exposure conditions which would be produced by Urban Runoff. They are an estimate of the relationship between continuous
exposure and intermittent, short duration exposures (several hours once every several days). Threshold concentrations are
those estimated to cause mortality of the most sensitive Individual ot the most sensitive species.
Significant Mortality concentrations are shown as a range which reflects 50 percent of the mo-it sensitive species and
mortality of the most sensitive Individual of the 25th percentile species sensitivity.
-------
an extensive set of numerical values derived from bioassay
studies.
- Estimates of "effects levels" which are suggested by NURP an-
alysis to be relevant for the intermittent exposures charac-
teristic of urban runoff.
By incorporating the numerical values for EPA's ambient water quality
criteria and the concentration levels suggested by NURP for intermittent
effects in the same table (or on the same graph in Chapter 7), a convenient,
concise comparison is provided of the practical implications of applying one
or the other as the yardstick for judging the protection or impairment of
water use. The two sets of numerical values thus provide measures for two of
the three options for defining a problem: violation of criteria or actual
impairment of a beneficial use.
Comparison of the pollutant concentrations in urban runoff showing the fre-
quency and magnitude of exceedance of ambient criteria and intermittent
effects levels provides a qualitative sense of the control requirements (and
implications regarding costs) attendant on the adoption of either problem
definition as the operative one.
Rivers and Streams
The approach adopted to quantify the water quality effects of urban runoff
for rivers and streams focuses on the inherent variability of the runoff
process. What occurs during an individual storm event is considered
secondary to the overall effect of a continuous spectrum of storms from very
small to very large. Of basic concern is the probability of occurrence of
water quality effects of some relevant magnitude.
To consider the intermittent and variable nature of urban runoff, a sto-
chastic approach was adopted. The method involves a direct calculation of
receiving water quality statistics using the statistical properties of the
urban runoff quality and other relevant variables. The approach uses a
relatively simple model of the physical behavior of the stream or river (as
compared to many of the deterministic simulation models). The results are
therefore an approximation, but appropriate as a screening tool.
The theoretical basis of the technique is quite powerful as it permits the
stochastic nature of runoff process to be explicitly considered., Application
is relatively straightforward, and the procedure is relevant to a wide
variety of cases. These attributes are particularly advantageous given the
national scope of the NURP assessment. The details of the stochastic method
are summarized and presented below.
Figure 5-2 contains an idealized representation of urban runoff discharges
entering a stream. The discharges usually enter the stream at several loca-
tions but are considered here to be adequately represented by an equivalent
discharge flow which enters the system at a single point.
Receiving water concentration (CO) is the resulting concentration after com-
plete mixing of the runoff and stream flows and is interpreted as the mean
-------
tM
00
URBAN RUNOFF
QR =FLOW
CR-CONCENTRATION
STREAM FLOW
UPSTREAM
QS=FLOW
CS =CONCENTRAT10N
DOWNSTREAM
(AFTER MIXING)
Q0= FLOW
CO = CONCENTRATION
Figure 5-2. Idealized Representation of Urban Runoff Discharges
Entering a Stream
stream concentration just downstream of all of the discharges as shown in
Figure 5-2. The four input variables considered are:
- Urban runoff flow (QR)
- Urban runoff concentration (CR)
- Stream flow (QS)
Stream concentration (CS)
Each is considered to be a stochastic random variable, which together combine
to determine downstream flow and concentration. In addition, all variables
are assumed to be independent, except urban runoff flow and streamflow where
correlation effects can be incorporated as warranted.
-------
PBKEOT Of STOM fVHTt EOIU1 TO 00 UO* TOM
1.1
Figure 7-4. Probability Distributions of Pollutant Concentrations
During Storm Runoff Periods
mum rant ttmmn -MO*
MM urn - IN
•UO RKUUKKE ItTFWU TUBS
Figure 7-5. Recurrence Intervals for Pollutant Concentrations
-------
AQUATIC IN-PLACE POLLUTANTS
(f ID
ABSTRACT
Pollutants now residing in aquatic sediments may originate
from sources currently operating and from past sources now
discontinued. Point and nonpoint sources, spills, and atmospheric
deposition, the major sources for water pollutants, are also the
major sources for sediment contaminants.
Accumulations of contaminated sediments usually occur in
areas having reduced current velocities, usually harbors, bays,
lakes, and impoundments. Contaminants of greatest concern are
usually metals, hydrophobic persistent organics, and the nutrient
phosphorus.
Sediments at a particular site may be a concern (a) because
ecological structure or function are believed to be impacted,
(b) because fish tissue residues are elevated to levels that are
believed to be hazardous to human health, or (c) simply because
contaminant concentrations in sediment seem unusually high.
The overall extent and severity of the problem are uncertain.
However, there are hundreds of sites with toxicant concentrations
at levels of concern to environmental scientists and managers, and
perhaps thousands of lakes and ponds with eutrophication exacerbated
by sediment phosphorus cycling.
DISCUSSION
Pollutants currently residing in aquatic systems may be
termed "in-place" pollutants. For a particular water body at a
particular time the quantity of a pollutant in-place is determined
by the past rates of (a) pollutant input to the system and
(b) pollutant depuration by the system.
Depuration processes act to reduce concentrations by
eliminating pollutant from the system. Physical processes (such
as downstream transport or burial under new sediment) transfer
material elsewhere. On the other hand, chemical processes (such
as biological degradation) change the identity and properties of
the material. Depuration rates are usually much slower for the
bottom sediments than for the overlying waters; consequently, the
term "in-place" is generally associated with sediment pollutants.
The sources of pollutants to aquatic sediments are the same
as those to surface waters: primarily point and nonpoint sources,
spills, and atmospheric inputs. As the Comparative Risk Project
is addressing the pollutant sources to water separately, it might
be assumed that the inclusion of in-place sediment pollutants as
an independent problem was intended to address existing sediment
-------
contamination caused by past sources now discontinued. (In such
case the regulatory choices would concern whether or not to
intervene to hasten depuration of the aquatic system.) For the
purposes of the Comparative Risk Project, however, it is not
possible on a nationwide basis to distinguish sediment contamination
problems on the of basis of whether or not their sources have
been discontinued. Consequently, the coverage of this paper
partially overlaps with other papers.
The ecological effects of sediment pollutants vary with
the type of pollutant as follows.
Oxygen demanding materials;
Biological oxidation of such material reduces dissolved
oxygen levels of the sediment interstitial (pore) water and the
overlying water column, possibly impairing aquatic organisms.
While dissolved oxygen problems are relatively common, sediment
oxygen demand is only one contributor. Low current velocities
and stratification promote sediment mediated dissolved oxygen
problems. Nevertheless, as the half-life for sediment oxygen
demand is probably relatively short, (perhaps measured in months),
residuals from discontinued sources are not thought to be a
problem.
Nutrients:
Lakes tend to trap the nutrient phosphorus released from
their watersheds. Abating nutrient sources to lakes having a
substantial history of algal nuisance generally will not solve
the problem, because the cycling of nutrients between sediments
and overlying waters will tend to support algal growth for many
years. Consequently, in-place nutrients are a significant problem
in many lakes and possibly some estuaries.
Toxicants;
Hydrophobic organics and metals tend to partition strongly
to sediment. Ecological impairment by accumulations of such
toxicants in bottom sediments is generally thought not to require
mediation by the overlying waters (although sediment interstitial
waters are suspected to play a key role). Benthic macroinvertebrates
and bottom feeding fish may receive the most immediate exposure,
although the resulting structural and functional changes or food
web contamination may affect other organisms as well.
Regulatory efforts to address sediment contamination by
toxicants are relatively recent. While field measurements of
some sediment contaminants have been made over many years, reliable
criteria for defining unacceptably high concentrations have not
been developed. Some of the possible approaches for deriving
criteria include: (a) comparison with "background" concentrations:
a simple, often-used, but arbitrary approach lacking any relation-
-------
ship with ecological effects; (b) bioassay: direct measurements
of sediment toxicity using single-species tests in the laboratory,
without reference to particular chemical agents; (c) field-based
criteria: maximum contaminant concentrations that biota have
been observed to tolerate in the field, based on biological and
chemical field measurements at many sites; (d) equilibrium
sediment-water partitioning: existing water quality criteria
applied to interstitial waters, assuming partitioning equilibrium.
The lack of established criteria for judging acceptable
degrees of sediment contamination hampers assessment of the
extent and severity of sediment contamination problems. Neverthe-
less, a nationwide survey of information on sediment contamination,
contracted by OWRS, produced a number of findings:
(a) There are hundreds of sites in the U.S. having sediment
contaminants at concentrations of concern to environmental
scientists and managers. The basis for concern varies.
At many sites all that is known is that the chemical
concentrations in sediment seem abnormally high. At other
sites contaminant concentrations in fish tissue are considered
hazardous to human consumers. At some sites ecological
effects have been found. [In-house analyses have found high
correlations between sediment contaminant levels and
macroinvertebrate diversity in widely differing rivers.]
(b) The magnitude of the problem in terms of areal extent and
severity cannot now be rigorously assessed and is highly
uncertain. Based on information available it was suspected
that severe problems might exist in perhaps 1% of the river
miles, 0.1% of the lake and estuary area, and 0.01% of the
offshore marine area. (The U.S. has 1,800,000 miles of
rivers, 62,000 square miles of lakes, and excluding Alaska
32,000 square miles of estuaries.)
(c) Municipal and industrial point sources, urban and agricultural
runoff, combined sewer overflows, spills, mine drainage,
and atmospheric deposition are frequently cited sources.
Many of the worst cases of sediment contamination are
associated with sources that have since been discontinued.
However, the overall importance of residuals from discontinued
sources is unknown.
(d) In addition to source locations, hydrological and benthal
characteristics affect geographical patterns of sediment
contamination. Fine grained particles with high surface-to-
volume ratios and/or high organic content readily sorb
hydrophobic pollutants. Contaminated sediments tend to
accumulate where sediment laden streams enter quiescent
waters. Harbor areas, both freshwater and marine, have
been impacted most severely, although problems have been
reported in all types of water bodies (streams, lakes,
estuaries, and coastal waters).
-------
(e) Sediment contaminants are most likely to be nonvolatile,
persistent, and hydrophobic. Metals are most frequently
cited as problems. PCBs, PAHs, and pesticides are also
frequently mentioned.
(f) The persistence of contaminated sediments is difficult to
predict; time frames are likely to be measured in years,
decades, or possibly centuries. Depuration processes include
downstream transport, burial, and chemical degradation. The
effectiveness of potential actions to speed cleansing of
sediments is likewise not well understood. Such actions may
include dredging of sediments for disposal elsewhere, or
in situ capping (burial).
The nationwide assessment gathered information on 155 sites.
A summary of eight representative sites, shown in the Table 1,
illustrates many of the variations in the nature of and knowledge
of the problems. Ecological effects are only one of the concerns.
Primary References
Lyman, W.J. et al. 1986. An overview of sediment quality
in the United States. EPA, OWRS. Draft.
McCarty, P.L. 1970. Chemistry of nitrogen and phosphorus in
water. J. AWWA, 62 (2): 127.
C. Delos 11/20/86
-------
Table 1: Summary information for 8 of 155 sites considered
in nationwide assessment.
Water Body
Boston
Harbor
Contaminants
PAHs
PCBs
coprostanol
South River Hg
VA
Jacksonville Metals
Port, PL
Origin of
Contaminants
Many point sources
Urban runoff
Sludge disposal
Sediment disposal
Ship traffic
Industrial
spill
None mentioned
Perceived
Impact
Structure
and health
of benthos
Fish tissue
exceeds FDA
action level
None mentioned
Bayou Casotte
MS
Capitol Lake
LA
Petroleum
hydrocarbons
PCBs
Industrial
spills
Industrial
point source
Spills
Runoff
None mentioned
Ecosystem
structure and
function
Lake Erie,
Western
L. Michigan,
Sheboygan
Harbor
Commencement
Bay
WA
Several
organics
PCBs
PCBs
PAHs
Other organics
Some metals
Unknown
Discontinued
industrial
source
Industrial
sources
None mentioned
Fish consumption
advisory
Fish tumors,
fish tissue
contamination
-------
RBastian3Feb87
SUBJECT: Summary of Contaminated Sludge/Ecological Risk Assessment
The sludges produced from many of the pollution control systems
designed to clean-up contaminated air, water or soil have been safely
recycled as soil conditioners, fill and construct ion materials .
However, disposal of the ever increasing volumes of ''contaminated
sludges'* produced as a byproduct of pollution control efforts can
pose a number of serious environmental risks unless adequate
precautions are taken to prevent contamination of ecosystems
associated with the receiving environment.
Some of the key factors in evaluating the potential ecological
risk associated with the disposal of contaminated sludge include the
following:
o The volumes of sludges are growing dramatically as a result of
increased pollution control activities
o Sludge quality is highly variable; some sludges may contain high
concentrations of a wide variety of toxic pollutants
o Effective enforcement of regulatory requirements at sludge
disposal sites is highly variable
o "While little data exists on the number or extent of ecological
problems which have occurred as a result of land disposal of
contaminated sludges, anecdotal accounts and concerns abound
o Much of the extensive literature available on the fate and impact
of individual chemicals that may be present in contaminated
sludges is based upon controlled lab studies and it very
difficult to translate lab measurements of effects upon
individuals to potential effects upon natural populations
o Only limited attempts have been taken to date to document direct
in-field impacts to natural ecosystems as a result of
contaminated sludge disposal projects
o Examples do exist of past contaminated waste disposal practices
creating serious threats to human health and incidents of
extensive ecosystem degradation
An attempt was made at rating the ecological risk associated with
the disposal of contaminated sludge under current plus reasonably
anticipated future regulatory programs. This effort suggests that the
disposal of contaminated sludge should not be expected to result in
extensive damage to natural ecosystems where reasonably anticipated
control programs are properly implemented. However, if the
permitting/monitoring/enforcement efforts that are currently in place
and anticpated to be implemented in the future are not carried out,
the improper disposal of contaminated sludges could lead to major
ecosystem damage.
-------
RBastian20Nov86
SUBJECT: Contaminated Sludge/Ecological Risk Assessment
I. Introduction to Problem
Pollution control systems are designed to clean-up contaminated
air, water, or soil. In most cases these systems not only produce
clean air, water, or soil, but also concentrate many of the
contaminants which have been removed into a residual "sludge." "While
the sludges produced from many of these treatment systems have been
safely recycled as soil conditioners, fill and construction materials,
disposal of "contaminated sludges" can pose a number of serious
environmental risks unless adequate precautions are taken to prevent
contamination of ecosystems associated with the receiving environment.
Current sludge disposal practices involve various forms of land
application, landfilling, incineration and ocean disposal - thus,
leading to the potential for interacting with both terrestrial and
aquatic ecosystems.
II. Detailed Description of Problem
SOURCES .... As noted in a recent OW cross-media analysis of sludge
management, the management of municipal and industrial sludge is a
growing problem. The sources involve over 15,000 municipal wastewater
treatment plants (which also serve at least 87,000 industrial
contributors), and over 38,000 industrial facilities nationwide.
Since 1972, municipal sludge has doubled in volume to over 7 million
dry metric tons annually. Another doubling of municipal sludge
quantities is expected by the year 2000 as a result of both the
construction of new publicly owned treatment works (POTWs) and the
addition of better treatment at some existing POTWs. In addition, the
.industrial sector produces an even larger volume of sludge from
industrial wastewater processing: 4 million dry metric tons of
hazardous sludges and 200 million dry metric tons of non-hazardous
sludges annually. When including the sludge volume generated from all
industrial pollution treatment, including scrubbing of furnace stacks
and other air emissions, the total amount of industrial pollution
treatment sludges are expected to reach more than 262 million tons
annually by 1987. (see Table 1)
EXPOSURES .... Sludge quality is highly variable. Some sludges are
relatively "clean" and can be used for beneficial purposes while other
sludges may contain high levels of toxic organic or inorganic chemical
pollutants, and/or pathogens. (see Table 3) The relatively clean
sludges are currently used or disposed of by landfilling; land
application to agricultural land, forests, mined lands, etc.; given
away or sold for use as soil conditioners; incinerated; disposed of
into the ocean through outfalls or by ocean dumping; o:r stored for
future use or disposal. Other sludges may contain high concentrations
of a wide variety of toxic pollutants: a number of industrial sludges
are listed hazardous wastes. The more contaminated sludges generally
are stored on-site or transported to hazardous waste treatment,
storage, or disposal facilities - often hazardous waste landfills,
lagoons, or incinerators. (see Table 2) Concern has been expressed
over the adequacy of such facilities to assimilate, contain or destroy
the contaminants present in these sludges so as to prevent their
escape into nearby environments.
-------
-2-
CQNTRQLS .... On paper, there are existing EPA regulations and
programs (and State programs) that could be expected to control nearly
all of the sludge use and disposal practices in one manner or another.
However, the regulation of sludge disposal management involves
provisions under many different laws (e.g., CffA, CAA, RCRA, MPRSA,
TSCA) and corresponding Agency programs. A recent OW cross-media
analysis of sludge management provided the following observations
concerning the Agency's current approach to regulating sludge
management practices:
o EPA's approach to sludge management is not one that has been
clearly laid out.
o The regulation of different sludges is inconsistent across the
vairous EPA media.
o The Agency may not be effectively regulating all industrial
sludges.
o Better information on the toxicology, treatability and generation
of specific pollutants is needed to determine which pollutants
to regulate in sludge.
o There is no new funding for sludge management and enforcement,
despite potential new burdens for some program activities.
The conclusions of the OW cross-media study included:
o The sludge problem is important and pervasive, and the municipal
sludge problem, in piaticular, is the subject of intense
Congressional and public interest.
o For the most part, Agency sludge management related program
activities are receiving adequate priority. The most
noteworthy exceptions are non-hazardous industrial sludge
management (where sludge volume is greatest but where attention
and funding are minimal) and State Programs.
STATUS OF AVATLABLE INFORMATION Information-wise, we are in
fairly good shape concerning information on the fate and effect of
only some of the many different chemical pollutants and pathogens
associated with sludges. Yet our overall information-base on
recommended municipal sludge management practices is quite good,
especially when compared with the available information associated
with the disposal of many of the industrial sludges that may contain
high concentrations of various toxic pollutants. 'While it is clear
that a better understanding of the fate and effect of all chemical
pollutants that may be present in municipal sludge would be helpful in
assuring adequate protection of public health and the environment, to
date few cases of significant environmental problems have been
documented as resulting from the reuse or disposal of municipal sludge
even when good management practices have not been followed. On the
other hand, a number of industrial sludges are listed hazardous wastes
and numerous Superfund sites have been listed as a result of past poor
industrial sludge disposal practices. Apparently as a result of the
Agency's focus on protecting human health, there appears to have been
only limited attempts taken to date to document direct in-field
impacts to natural ecosystems as a result of contaminated sludge
disposal practices. While elevated levels of toxic metals and organic
compounds have been documented as present in various plant and animal
tissues in flora and fauna present in or near certain sludge reuse and
disposal facilities, just what the longterm impacts of these increased
body burdens mean has not been determined or studied to any serious
extent.
-------
-3-
III. Evaluation of the Problem
Terrestrial and Freshwater Ecosystems
Impacts on terrestrial and affiliated freshwater ecosystems
resulting from land-based disposal or use of contaminated sludge are
quite distinct from those of ocean disposal. Because man is generally
in more direct contract with terrestrial ecosystems, the strategy for
waste disposal on land has traditionally been one of containment.
There has also been considerable use of land application systems
designed to both treat and recycle wastes of an acceptable quality in
a more dispersive manner in which the soil serves as a "living filter"
to help treat the waste while the waste serves as an organic nutrient
source or soil conditioner. In either case, however, concerns over
impacts from land-based treatment and disposal or application
practices are usually less focused on large-scale contamination of
natural resources or destruction of ecological systems within the
disposal site, but rather directed at the potential export of
contaminants to other ecological systems, contamination of surface-
and groundwater resources, secondary effects on valuable natural and
agricultural lands, and direct threats to human health.
Specific ecological (non-human) concerns for land disposal
include: (l) the transport of toxic organics and heavy metals through
surface and groundwaters or plant uptake by vegetation grown on
sludge-amended soils, with potential ecological effects, such as
contamination of animal foodchains; and (2) the export of nutrients,
toxic organics and heavy metals from land disposal sites (e.g., via
leachates or surface runoff) to non-target ecological systems, such as
nearby streams and wetlands, and the possible destruction of wildlife
habitats and unique ecosystems. Selection of land disposal sites,
therefore, must consider not only the hydrological and geological
suitability of the site for treatment, containment or recycling of
wastes, but also the resiliency of the ecosystem and adjacent
ecosystems to damage. Some of the engineering and environmental
considerations applicable to land disposal practices are presented in
Figure 1.
There are a large number of terrestrial sludge treatment and
disposal options currently in use, including both systems designed
primarily for waste disposal, such as landfills, deep well injection
systems, storage pits, ponds and lagoons, and high rate land
application systems; and others designed with recycling as a intergral
aspect of disposal. Treatment and recycling systems may involve, a
variety of managed natural or man-made "ecosystems" (e.g.,
agricultural lands, forests, disturbed lands, etc.). In many cases
the terrestrial ecosystems can serve as an integral part of waste
treatment and reuse systems rather than just a location for waste
disposal. In certain instances wastes can and have been effectively
used as a component of ecosystem management programs such as enhancing
the diversity and productivity of such areas as mine spoils and other
drastically disturbed lands (Benforado and Bastian, 1985; Bastian,
1982; Sopper et al., 1982; Schaller and Sutton, 1978).
-------
-4-
The major concerns in site selection for land disposal practices
are to ensure that: (1) ground-water and surface water resources in
and around the disposal site do not become contaminated beyond
acceptable levels; (2) land-use patterns are not compromised; (3)
unique ecosystems and habitats are preserved; and (4) soi1-amendments
do not result in transfer of contaminants to plants and animals and to
the human food chain (U.S. NRC, 1984a; U.S. EPA 1983, 1981).
Predictions of contaminant migration to groundwater and surface water
and to non-target ecosystems require an understanding of the processes
controlling transport, hydrodynamic dispersion, and the physical,
chemical, and biolgical reactions that affect contaminant
distributions at a given site for a given period of time (U.S. NRC,
1984c). Criteria used for the selection of a disposal containment
site, therefore, are such that the geologic, geochemical, and
hydrologic characteristics should isolate the wastes from the
biosphere for a long period of time. On the other hand, criteria for
recycling projects are generally more dependent upon limiting the
contaminant levels in the wastes involved and controlling loading
rates to what can be effectively treated and/or used by the natural or
man-made ecosystems involved.
It is when these basic criteria for waste disposal and recycling
projects are not followed that ecosystem impacts are most likely to
occur. The long list of potential Superfund sites serves as a legacy
of bad waste disposal practices that have been practiced in the past.
Although limited, some data have been generated that suggest potential
ecological problems associated with such sites. The continuing
studies since 1979 of voles living near New York's imfamous Love Canal
in the City of Niagra Falls undertaken by John Christian and others
from SUNY-Binghamton have shown that voles living close to the waste
disposal site appear to have shorter life spans and suffer from
delayed maturation in males, reproductive problems in females, liver
damage when compared to animals living further away from the site.
While there are few data on the number or extent of ecological
problems which have occurred as a result of land disposal of
contaminated sludges, anecdotal accounts and concerns abound.
Situations where excessive loading rates or inappropriate disposal
site characterists may have led to sludge-borne contaminants in runoff
from fields or leachates from landfills reaching nearby surface
streams to cause fish kills or contaminate water supplies and
vegetation have been reported. While enhanced wi Idlife reproduction
and general ecosystem production rates often appear to increase on
well designed and operated sites, elevated levels of sludge-borne
contaminants in the blood stream and vital organs have been reported
in small mammals and other consumers of vegetation grown on sludge
amended sites (Cole et al, 1986; Page et al, 1983; Davis et al, 1983;
Sopper et al, 1982; Anderson et al, 1982; Bledsoe, 1981). Clearly,
increased vegetation uptake of many sludge-borne contaminants has been
demonstrated at many land disposal sites, as has elevated levels of
metals in certain body tissues by domestic animals either fed crops
grown on sludge amended fields or directly fed dried sludge as a part
of their feed ration (CAST, 1976; Bitton et al, 1980; Page et al,
1983; Page and Logan, 1986). But just what sub-lethal increases in
body burdens of such contaminants in wildlife which consume this
vegetation may mean over the long term to the ecosystem involved has
yet to be determined or even studied to any serious extent.
-------
-5-
Marine Ecosystems
The impacts of contaminated sludge or other waste disposal in the
marine environment is dependent on the composition and volume of
waste involved and on the dispersal and transport characteristics of
the site used for disposal. Contaminants of most concern to marine
ecosystems, such as pathogenic microorganisms, trace metals and toxic
organic compounds are associated primarily with particulate matter.
Transport of contaminants within coastal areas coincides with sediment
transport processes and, thus, such material tends to accumulate in
depositional areas. There have been numerous examples around the
world showing how sediment deposits in coastal areas reflect waste
disposal histories. The distribution, fate, and effects of wastes
disposed of in the ocean are governed by the physical, chemical, and
biological processes that generally reduce the concentration, alter
the chemical form and ultimately eliminate them from the water column.
Transfer of contaminants to marine biota and disturbance of ecological
systems for the most part are dependent on the availability and
persistence of contaminants in benthic ecosystems.
With the exception of extremely hazardous wastes, such as high
level radioactive wastes that may be containerized before disposal and
dredge material that may be contained in a submarine pit and capped,
the containment strategy generally employed as a basis for land
disposal practices is generally not feasible for disposal of most
wastes in the ocean. Resuspension and transport of materials by
bottom currents and degradation and recycling of materials in
biogeochemi cal cycles are natural dispersal mechanisms (see Figure 2).
Waste disposal in areas of restricted circulaiton, such as basins,
will possibly permit the buildup of biological systems that can
accelerate the decomposition of relatively non-toxic wastes in a
fashion analagous to composting on land, but this has not been well
studied.
In general, degradation of benthic habitats as a result of
waste disposal has usually been attributed to high levels of organic
enrichment in bottom sediments (Boesch, 1982; Pearson and Rosenberg,
1978). The delineation between observed benthic effects of waste
disposal at nondispersive sites and no observed effects at dispersive
sites suggests that wide dispersal may be not only the most feasible
disposal option but also the preferred one. However, unlike the
situation wi th land application practices, little effort has been
directed toward managing or stimulating the beneficial effects, such
as increased productivity (Ryther and Dunstan, 1971), that may result
from waste disposal in the marine environment.
Ecological concerns with contaminated sludge disposal in the ocean
include: (l) uptake and accumulation of chemical contaminants in
marine organisms to toxic levels, their effects on the survival and
reproduction of marine organisms and the resulting impact on marine
ecosystems, and (2) the release of biodegradable organic matter and
nutrients, which under quiescent conditions may result in localized
eutrophication, organic enrichment, and oxygen depletion (Capuzzo et
al., 1985). To minimize organic loading and accumulation of sludge
contaminants in marine organimsms, disposal of these wastes in the
ocean should occur in areas where horizontal dispersion distributes
the waste over a wide geographic area, this preventing overloading of
-------
-6-
natural microbial and biochemical processes, severe alterations in
macrobenthic communities, and accumulation of contaminants in the
benthos. Deep-water or offshore disposal of contaminated sludges
offers several advantages in meeting these criteria in comparison with
nearshore disposal - specifically, greater dilution and dispersion of
the wastes and reduced potential of contaminants being transferred
through the marine foodchain.
As with terrestrial systems, it is when these basic concepts for
ocean disposal are not followed that ecosystem impacts are most likely
to occur. While there are only a few examples of ocean disposal of
contaminated sludge and related wastes in the U.S. today, the impacts
of both current and past practices continue to face EPA as a
regulatory agency. Ocean disposal of sludge (and/or poorly treated
wastewater) thioxigh outfalls in Southern California, into Puget Sound,
and into Boston Harbor, and ocean dumping at the 12 mile site in the
New York Bight lead to dramatic changes in benthic communities,
including increases in total productivity and reductions in species
numbers (see Myers and Harding,1983; and especially Mearns and Young,
1983). Increases in benthic fish body-burdens of contaminants and
certain diseases such as fin erosion and skin tumors in these areas
have also been noted. Contaminated sediments from past industrial
discharges (in some cases with pollutant concentrations much higher
than most sludges produced today) have lead to closure of extensive
shellfish beds and Superfund site designations in Puget Sound and
Narragansett Bay. Consideration is still being given to the possible
designation of a portion of the Santa Monica Basin near Palos Verdes
Peninsula off Southern California due to high levels of DDT and PCB's
in bottom sediments which accumulated as a result of contaminated
industrial wastes being discharged through a municipal outfall in past
years .
Degree of Ecological Risk from Contaminated Sludge
Much of the extensive literature that is available on the fate and
impact of individual chemicals that may be present in contaminated
sludges is based upon controlled laboratory studies. And it must be
remembered that it is very difficult to translate lab measurements of
effects upon individuals to potential effects upon natural populations
since the latter are also influenced by interactions among population
members and with the physical environment (Levin et al, 1984).
However, at least in the case of sewage sludge, there has been a
considerable amount of field data collected on the fate of nutrients
and trace metals, and to a lesser extent toxic organic compounds and
pathogens, under a wide array of environmental conditions that can
help temper the conclusions that may be drawn from using only lab
data.
Table 4 summarizes the types of concerns for both ecological
damage and human health impacts that effective management of waste
(including contaminated sludge) systems should consider for a variety
of ecosystems. Such a framework may be useful in evaluating the
ecological concerns of cross ecosystem comparisons of contaminated
sludge disposal impacts. Our knowledge of the dynamics of these
ecosystems is by no means complete. Yet, we have sufficient knowledge
to make reasonable first-order predictions of the impacts of
-------
-7-
contaminated wastes on ecosystem processes to avoid serious threats to
human health, as resulted from mercury disposal in Minimata Bay, and
incidents of extensive ecosystem degradation. Consideration of these
ecological principles combined with engineering design for specific
waste disposal or reuse systems should become an integral component of
the decision making process for waste management.
Rating of ecological risk
An attempt at rating the ecological risk associated with the
disposal of contaminated sludge under current plus reasonably
anticipated future regulatory programs using the method adopted by the
workgroup follows:
Recommended
Rat ing
Freshwater ecosystems
o buffered & unbuffered lakes M
o buffered & unbuffered streams L
Marine and estuarine ecosystems
o coastal ecosystems M
o open ocean ecosystems L
o estuaries M
Terrestrial ecosystems
o coniferous & deciduous forests L
o grassland ecosystems M
o desert and semi-arid ecosystems L
o alpine and tundra ecosystems L
Wetland ecosystems
o buffered & unbuffered freshwater
isolated wetlands M
o freshwater flowing we tlands M
o saltwater wetlands L
This rating suggests that the disposal of contaminated sludge should
not be expected to result in extensive damage to natural ecosystems
where current plus reasonably anticipated control programs are
properly implemented. However, since contaminated sludges are clearly
a potentially significant source of BOD, solids, nutrients, toxic
inorganics and organics, and pathogens, if the permitting/monitoring/
enforcement efforts that are currently in place and anticipated to be
implemented in the future are not carried out, this rating could well
change dramatically and suggest that the disposal of contaminated
sludges could lead to major ecosystem damage.
-------
FOOTNOTE; For years extensive research was undertaken to study
radiatjor effects on ecosystems. As as a result there was extensive
literature generated on the responses of many species to various
levels and types of radiation exposure. In some cases large-scale
field studies were even undertaken (e.g., Hubbard Brook and Puerto
Rico studies as well as 1ongterm monitor ing of the Nevada and South
Pacific Test Sites). Yet, much of the research as well as our
regulatory considerations of the ecosystem effects associated with
radiation has been based on extrapolations from laboratory studies on
single organisms and populations - in spite of the known difficulties
in extrapolating from lab experiments to natural systems and the lack
of longterm observations on responses of natural ecosystems to chronic
low level irradiation - and field studies which support the suggestion
that extrapolation from lab results may overestimate the radio-
resistance of free ranging animal populations, probably as a result of
other sources of stress on these populations (see Gushing, 1976).
fNOTE; Much of the content of this draft paper was based upon a
paper, titled "Ecological and Human Health Criteria for Cross
Ecosystem Comparison of Impacts of Waste Management Pracitces"
prepared by Judith Capuzzo and John Teal from Woods Hole along with
Bob Bastian from EPA which was presented the NATO conference on
"Scientific Basis for the Role of the Oceans as a Waste Disposal
Option" held 24-30 April 1985 in Vi lamoura.Portugal]
-------
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-------
-10-
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-------
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-------
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-------
DUN '
03
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-------
Figure 2. Input and Crancport of wastes In Marine
ecosystea*. Frovt Farrington et al.
(1982). Artist. Kevin King (OCEANUS
Magazine).
-------
Table 1. Approximate Man of Sludge Generated by Pollution
Control Activities*
Total Sludge
Type of Sludge dMT/yrl
Air Pollution Control .
- electric utilities 50 x 1(K
- other : 43 x 10
Drinking Water Treatment0 4 x 10
6
Industrial Waste-water Treatment 16 x 10
Municipal Wastewater Treatment 7 x 10
based on data from JRB. Assoc. December 1983 Report to
U.S. EPA. ''Inventory of Air Pollution Control, Industrial
. Wastewater Treatment and Water Treatment Sludges'*
fly ash & scrubber sludges
. surface & groundwater
iron & steel, inorganic chemicals, food processing, and
pulp & paper manufacturing account for 90% of the total
Table 2. Current Disposal Practices for Sludges Generated by
Pollution Control Activities
Type of Sludge
Air Pollution Cont .
Drinking Water Trt.
Industrial Waste-
La coons
X
X
X
Land-
f i ll
X
X
X
Land
Appl .
X
X
D&M/
leu86
X
X
Ocean
Inc in • DI sp .
X x
water Trt.
Municipal Waste-
water Trt.
-------
Table 3. C.omnon Sludge Cons t i tut en t s'
Type of Sludge
Air Pol lut i on
Cont ro 1
Dr inking Wa t e r
Trea tment
I ndus trial
Wa s t ewa t e r
Mun i c ipa 1
Wa s t ewa t e r
Treatment
Convent i ona 1
Or panics
None
Low
Low-
High
High
Convent i ona 1
I no r t an i c s
High
High
Low-
High
Low-
High
Tox i c
Me t a 1 s
Med i urn
Low
Low-
High
Low-
High
Tox i c
Or P an i c s
None
Low
Low-
High
Low-
High
Nutrients
Low
Low
Low-
High
Low-
High
Ha za r dous
Waste
Rarely
No
Seve ra 1
Catagories
Listed
Rare ly
based on data from JRB, Assoc., December 1983, Report to U.S. EPA, ''Inventory, of Air
Pollution Control, Industrial Wastewater Treatment and Water Treatment Sludges'*
-------
T«liK-4. Kt-ul
i
2
2
3
3
3
3
1
0
3
3
3
•*
1
3
3
3
3
1
NOTES: Species Extinction: 3 - greatest concern.
Habitat Loss -loss of • significant portion of a habitat type: 1 - greatest concern.
Elevated Nutrients: 3 - highest probability of change to ecosystem.
Rccovcrablllty -ability of system to repair itself after input cease*: 3 • slowest
recovery, decade* to centuries; 1 • rapid recovery, year*.
Containment -ability of unmodified ayatern to restrict spread of input*: 3 •
greatest difficulty.
Remedial Action -ease with which we con repair doMge to ecosystem: 3 - greatest
difficulty.
Uncertainty: 3 - highest uncertainty.
Visibility: 3 - most visible.
Pathogen Route* to Society: 3 • highest probability of reaching society.
Toxicant Route* to Society: 3 • highest probability of reaching society.
. Disturbed Land* -land highly modified by human activity.
Remnants -isolated natural *pot* within developed or otherwise highly modified area.
-------
STATISTICS ON SEWAGE SLUDGE
• 15,300 POTWs generate 7.6 million dry metric tons of sewage
sludge per year (as compared to 204 million dry metric
tons of industrial sludges)
* Sewage sludge is disposed of as follows:
- 46.4% by landfilling and surface impoundments (1.5% by
mono-landfilling) (25% in 1976)
- 25.4% by land application including distribution and
marketing (25% in 1976)
- 20.3% by incineration (35% in 1976)
- 6.6% by ocean disposal (15% in 1976)
-------
COM>ARATIVE RISK ASSESSF€NT PROJECT
PHYSICAL ALTERATION OF AQUATIC HABITATS
I. Overview and General Conclusions
Problems #13 and #14 have been redefined by the Ecological Risk Work-
group Into a single new category; "Physical alteration of Aquatic Habitats."
Physical Impacts to aquatic systems result from activities such as dredge
and fill discharges, channelization, drainage, Impoundment, mining and
extraction, shoreline stabilization and silviculture and agriculture activi-
ties. Physical Impacts, Including direct, Indirect and cumulative effects,
are manifested in four general categories of the most damaging ecological
effects occurring 1n marine, estuarlne, and freshwater systems:
1. Physical Habitat Alteration or Loss,
2. Addition of Suspended Solids (Including turbidity and sedimentation
effects),
3. Modification of Water Levels, Flow Regimes, and Circulation Patterns,
and
4. Changes to Ambient Water Parameters (e.g., 03, C02 temperature,
light) that result from physical alteration of aquatic systems.
Several conclusions regarding physical Impacts to aquatic systems can
be made:
1. Habitat loss or alteration 1s the most significant ecological effect
associated with physical Impacts to aquatic systems.
2. Wetland systems, particularly Isolated, freshwater wetlands, represent
the aquatic system subject to the greatest risk from physical impacts.
Deep ocean systems are currently at least risk.
3. Ecological risk to rivers and streams from physical stresses 1s also
very high, but the threats appear to be more regional in nature, with
the West representing the highest risk region.
4. Among the geographic areas subject to the greatest risk from physical
Impacts to aquatic systems are the Bottomland Hardwood riparian
wetlands of the Southeast, Prairie Pothole wetlands of the Midwest,
and the tundra wetlands, rivers and near coastal zone of Alaska's
North Slope. The physical threat to Bottomland Hardwood wetlands and
Prairie Pothole wetlands 1s associated with agricultural conver-
sion through filling and drainage activities while the threat to
arctic Alaskan aquatic systems Is from construction fill and gravel
mining activities attendant to oil and gas exploration.
-------
-2-
5. The development and application of regulatory controls should recog-
nize that the effects associated with physical impacts to aquatic
systems frequently involve the total elimination of ecological
values and functions of a site and that these effects may be irre-
versible. As a result, regulation should focus on preservation of
remaining aquatic systems, particularly in areas where cumulative
losses are significant.
II. Description of Environmental Problem and Impacts
A. Sources of Problem and Stress Agents
The Ecological Risk Workgroup has redefined Environmental Problems #13
("To Estuaries, Coastal Waters, and Oceans from All Sources") and #14
("To Wetlands from All Sources") as a single new category; "Physical Altera-
tion of Aquatic Habitats." For the purpose of evaluating ecological risk,
this category is intended to cover those impacts that result from the follow-
ing activities in marine, estuan'ne, and freshwater aquatic systems:
0 Dredge Spoil Disposal
0 Filling (for the purpose of creating fastland or altering bottom
contours and depth)
0 Channelization (including deepening, straightening, bank reconfigura-
tion, levee construction, culverting)
0 Other Dredging
0 Drainage
0 Shoreline Stabilization (including bulkheading and beach nourishment)
0 Placement of Structures
0 Impoundment
0 Mining and Extraction (excluding waste disposal)
0 Silviculture and Agriculture Practices
-------
-3-
These activities represent the "sources" or "stress agents" that cause
the physical alteration of aquatic habitats. Each type of activity is
attended by an identifiable suite of physical impacts. In turn, each type
of physical impact can be shown to induce a derived set of biological
effects, occurring directly, indirectly, or cumulatively, and which are at
least generally predictable. The most damaging effects to marine, estuarine,
and freshwater aquatic systems are derived as a consequence of direct habitat
loss or alteration, addition of suspended solids (turbidity), modification
of water levels and flow regimes, and changes to ambient water conditions
such as temperature, light, pH, nutrients, oxygen and carbon dioxide.
Chemical Impacts on the aquatic environment from anthropogenically derived
pollutants including heavy metals, radioactive isotopes, and pesticides
will not be .considered under this category.
B. Overview of Physical Impacts
There are several generalizations regarding physical impacts to aquatic
systems that, if described at this point, should help in evaluating the nature
of stresses on aquatic habitats.
1. Aquatic systems are eyolutionarily adapted to the naturally prevail-
ing suite of environmental' conditions.As a result, aquatic systems adapted
to a very narrow range of conditions (e.g., salinity, temperature, oxygen)
tend to be the most susceptible to even small introduced changes. Moreover,
the most damaging Impacts to any type of aquatic system are typically asso-
ciated with activities that Induce major or prolonged alteration of environ-
mental norms.
2. Natural aquatic systems are balanced at some middle range with
respect to most environmental factors.Disturbance from this state may
occur through deviation at either extreme, i.e., through deficiency or
excess of a given factor.
3. Although the general effects of a given type of activity can be
predicted with a reasonable level of confidence, details will vary with
local circumstances.
4. The single most important impact of man's activities in aquatic
systems is habitat alteration.Habitat, broadly defined as "the place
where an organism lives," encompasses those ecological features of an
area upon which the organism (or population, or community) is dependent
for survival; without these features the organism cannot survive. The
habitat value of a particular area is related to the abundance and diver-
sity of these required ecological features (e.g., cover, food sources,
nesting sites, resting areas, nursery areas). Habitat requirements vary
widely from species to species and, in general, the more habitat require-
ments (I.e., features) provided by a particular area, the greater its
value and consequently, the more significant its loss.
-------
-4-
5. The three principal types of physical Impacts to aquatic resources
are: 1) Direct Effects, 2) Indirect Effects, and 3) Cumulative Effect's^
Direct effects are caused by specific activities and occur at the same place
and time as the activity. Indirect effects are impacts on an aquatic system
that are associated with a particular activity, but occur later in time or
are farther removed in distance. Cumulative impacts are the changes in an
aquatic system that are attributable to the collective effect of a number
of individual activities that are occurring concurrently or that may have
occurred in the past, or that may reasonably occur in the future.
C. Scope of Physical Impacts to Aquatic Systems If
1. Marine and Estuarine Systems
a. Open Ocean Ecosystems
The environmental impact on deep ocean aquatic resources from physical
stresses is currently considered negligible. The primary reason is that
there are few activities which generate physical impacts that are now
widely conducted by man in the deep ocean.
It is anticipated that as the need for mineral and energy resources
increases in this country, and as the capital and technology necessary to
exploit deep sea-bed resources become available, the threat to poorly
studied abyssal communities will increase. Although the most significant
physical threat appears to be associated with future mining and extraction
activities, other potential water column and benthic physical impacts are
associated with deep ocean disposal practices, increased sedimentation
from rivers (particularly on the West and Gulf coasts where the continental
shelf is most narrow), and military construction for defense and reconnais-
sance purposes.
Equilibrium conditions in the ocean, particularly at abyssal depths,
are virtually constant and communities adapted to these conditions (e.g.,
light pressure temperature, salinity), are susceptible to even small per-
turbations. Future planning for activities in the deep ocean should
recognize the vulnerability of this system to anthropogenic impacts.
b. Shallow Coastal Waters [Coastal Ecosystems]
For the purposes of this analysis, shallow coastal waters are defined
as the submerged margins of the continent extending from the mean low water
line of the coast seaward to the edge of the continental shelf (depth approxi-
mately 600 feet).
If For purposes of this paper, we did not strictly follow the ecosystems
categories established by the expert panel since we believe that they
are more properly suited to chemical (vs. physical) impacts. Where
differences exist, corresponding panel categories are cross-referenced
in brackets.
-------
-5-
The Department of Commerce has estimated that by the year 2000, the
United States may have more than a trillion dollars invested offshore,
primarily in shallow, coastal waters. Coastal waters are utilized by man
for the commercial and recreational harvest of marine fisheries and are
a valuable source of numerous other products including petroleum, natural
gas, sulphur, phosphates, shell, sand, and gravel, and they are important
in marine transportation.
The scope of activities being conducted in shallow coastal waters is
currently expanding as terrestrial sources of mineral and energy resources
are exhausted. The most significant physical impact associated with man's
activities in coastal waters is the loss or modification of marine habitat.
The impacts tend to be localized as a consequence of the fact that mineral
and energy resources of the sea-bed occur primarily in scattered, highly
localized deposits and structures on top of, and within, the sediments and
rocks of the ocean floor. Large scale economic exploitation has so far
been confined largely to the U.S. continental shelf in waters less than
350 feet deep and within 70 miles of the coastline. Most current and
near-future activities are proposed for the U.S. Gulf, West, and Alaskan
coasts.
Oil and gas represent more than 90 percent by value of all minerals
obtained from near-coastal waters and have the greatest potential for the
future. The coastal waters of single greatest interest for oil and gas
development in the U.S., and also among the most susceptible to physical
impacts, are the shallow waters of Alaska's Beaufort Sea. The most
economical approach to energy development in the Beaufort Involves con-
struction of gravel causeways in the shallow coastal waters to connect
artificial, gravel production islands with processing and transportation
facilities on land. Demonstrated impacts of this type of fill discharge
in the shallow Beaufort Sea Include modified circulation patterns, changes
in temperature and salinity patterns, and direct loss of habitat. This
construction is being shown to affect the migration patterns of numerous
anadramous fishes, and the ability of these species to reach Beaufort Sea
feeding and rearing areas. There is also concern regarding the effects
of causeways and artificial islands on Beaufort Sea whale populations.
c. Estuaries
An estuary is the expanded mouth of a river near its entrance to the
sea. The estuary extends upstream or landward to where ocean derived salts
measure approximately .5 ppt and seaward to an imaginary line closing the
mouth of a river, bay, or sound to the ocean. The estuary is subject to
the influence of both the river and the sea, with salinity conditions
ranging from nearly fresh to marine (and in some cases higher). Due to
their juxtaposition between fresh and marine systems, estuaries are dynamic
environments characterized by species adapted to wide ranges in ambient
conditions. However, the stresses on organisms imposed by "natural" fluc-
tuations in ambient conditions frequently make them extremely vulnerable
to anthropogenic stresses to which they are not adapted.
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-6-
By the year 2000, half of the estimated 312-milllon U.S. population
will live on five percent of the land area in three coastal urban belts:
the megalopolises of the Atlantic, the Pacific, and the Great Lakes. Along
with the people will come an intensification of competing demands for the
limited resources of the narrow, fragile coastal zone, including in par-
ticular the major coastal estuaries.
The scope of activities with potential physical impacts being conducted
in estuarine waters is broad focusing principally on commercial development,
port and harbor maintenance, stabilization activities and agriculture
(associated non-point discharge impacts). Each of the major Atlantic,
Pacific and Gulf coast estuaries is showing some degree of stress from
physical impacts associated with man's activities. However, the Chesapeake
estuary on the Atlantic coast and the San Francisco and Puget Sound estuaries
of the Pacific coast appear currently'to be among the most vulnerable to the
anthropogenic stress that is accompanying increased development and utiliza-
tion of these estuaries.
The following activities are the principal source of physical impacts
causing observed declines in living resources in these estuaries:
1. Increased eutrophication from nutrient sources (sewage plants,
agricultural runoff),
2. Disruption of estuarine food webs due to wetlands loss, increased
turbidity, and sedimentation associated with dredge and fill dis-
posal, and mining activities (sand, gravel, phosphates), and
3. Loss of estuarine habitat including seagrass beds and spawning,
rearing and feeding areas as a result of dredge and fill disposal,
shoreline stabilization, and development activities.
d. Tidal Wetlands [Saltwater Wetlands and Freshwater Flowing
Wetlands, in part]
Tidal wetlands are lands transitional between terrestrial and aquatic
systems that are subject to the ebb and flow of the tides. Tidal wetlands
are generally characterized by one or more of the following attributes:
1) at least periodically, the land supports predominantly hydrophytic
vegetation, 2) the substrate is predominantly undrained hydric soils,
3) the substrate is saturated with water at some time during the growing
season each year. Salinity characteristics range from freshwater tidal
wetlands (1 40 ppt)
tidal wetlands.
There is a wide range of activities impacting tidal wetlands including
modification for agriculture; channelization for flood control; filling for
housing, highways, industry and sanitary landfills; dredging for navigation
channels, harbors and marinas; impoundment construction; timber harvest;
peat mining; oil and gas extraction; phosphate mining and others.
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-7-
The USFWS estimates that over half of the original tidal wetlands in
the lower 48 States have been destroyed. 482,000 acres of tidal wetlands
were lost during the period of the mid-501s to the mid-70's. Of these
losses, approximately 56 percent resulted from dredging for marinas, canals
and port development; 22 percent resulted from urbanization; 14 percent
from the disposal of dredged material or from beach creation; 6 percent
from the natural or man-induced transition of saltwater wetlands to
freshwater wetlands; and 2 percent from agriculture.
While the national decline in tidal wetlands is dramatic, losses in
particular regions and States are more startling. For example, reductions
in Pacific flyway migratory waterfowl have been directly correlated to the
conversion of approximately 90 percent of California's wetlands. In certain
areas, coastal wetland loss-rates continue to be important despite more
protective State and Federal laws. It is estimated, for example, that
Louisiana continues to lose 25,000 acres of its tidal wetlands each year.
Despite historic losses of tidal wetlands in the United States, this
resource is still actively sought by developers for residential and resort
housing, marinas, and other development. The focus of the current and
near-future loss of coastal wetlands is in the States of California,
Florida, Louisiana, New Jersey and Texas (Texas is the only State that has
not enacted special laws to protect coastal wetlands). Outside of Louisiana,
coastal wetlands losses are directly related to population density. Urban-
ization has been responsible for over 90% of the loss directly attributed
to physical activities.
An additional regional-scale source of hydrologic modification of
coastal wetlands that is becoming a significant threat to wetlands in the
Southeast is impoundment of tidal marshes for duck hunting and aquaculture.
This situation represents a classic example of the conflict between pre-
serving public resource interests and protecting the rights of private
ownership. Hundreds of thousands of acres of tidal wetlands in the South-
east are in private ownership but protected under public trust. Landowners
are more frequently seeking to "manage" their property for greater return
without actually converting their wetlands to uplands. The solution for
the landowner is to dike the wetlands into large impoundments that can
be managed for hunting or aquaculture. The consequence is that thousands
of acres, approximately 75,000 acres in South Carolina alone, are under
threat of being impounded and isolated from the adjacent estuarine system.
State and Federal laws that protect wetlands are difficult to apply in
these situations because impoundments remain aquatic systems, albeit
with vastly different characteristics than the marshes they replace.
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-8-
EPA has identified three areas of information where more study is
necessary to ensure effective and consistent wetlands protection;
1) mitigation, 2) cumulative impacts resulting from previous wetland
losses, and 3) the contribution of wetlands in protecting water quality.
The consistent evaluation of cumulative wetland impacts is particularly
important because much of the current losses are occurring on a piecemeal
basis where individual, direct impacts are small.
Future regulatory management of wetlands should focus on integrating
available controls. Although Section 404 of the Clean Watger Act is
helpful in controlling some types of activities in wetlands, development
of water quality standards for wetlands, non-point source pollution con-
trols, and other regulatory controls that can be applied in an integrated
approach would contribute to more effective regulation of wetlands.
2. Freshwater Systems
a. Rivers and Streams [Buffered and Unbuffered Streams]
Rivers and streams are lotic freshwater systems with directional flow
and which drain water from the continent to the ocean. They are extremely
diverse ecosystems which are typically susceptible to even small environ-
mental perturbations, such as changes in turbidity, flow, temperature, light,
dissolved oxygen and substrate.
Man continues to physically modify and impact rivers and streams on a
national scale for flood control, transportation, urban construction, agri-
culture, recreation, hydroelectric power, water supply, mining activities,
and other purposes. Recognizing the functions and values of rivers and
streams for recreational and commercial purposes, local, State, and Federal
laws are becoming increasingly effective in protecting these systems. However,
in specific areas, conflicting regional needs are resulting in significant
hydrologic modifications of rivers and streams.
In the water-scarce West and Southwest, natural water courses are being
channelized, diverted, and impounded to satisfy agricultural and commercial
users to the detriment of the environment. Placer mining In Alaska and the
Northwest is being carried out in stream beds, flood plains, and river banks
in search of gold and other minerals. This type of hydraulic mining requires
enormous quantities of water for digging and processing (up to 32,000 gal/
cubic yard). These operations destroy stream beds and alluvial valley soils,
and produce tremendous quantities of gravels, sands, and fine silts, which
enter streams creating turbidity and sedimentation problems. Flood control/
irrigation/hydroelectric projects continue to eliminate riparian habitat,
increase water temperature and turbidity, and alter normal circulation
patterns. The Garrison Diversion Project in North Dakota, for example,
continues despite recognized regional concerns regarding loss of critical
riparian habitat.
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-9-
b. Lakes
Lakes are lentic systems characterized by a large open water (limnetic)
zone compared with the extent of the shallow water (littoral) zone. The
"producing" region in lakes (region where light energy is fixed by phyto-
plankton into food) is in the limnetic zone. Thus, it is this limnetic
zone and the nature of the bottom and its biota that are of the greatest
interest in assessing potential impacts to lake environments.
Most of the physical impacts to lakes result from modification of the
littoral zone. These activities Include bulkheading, filling for recrea-
tional and commercial purposes, shoreline stabilization, and agriculture
and silviculture practices occurring on the lake margin. Because the
critical region in lakes (limnetic zone) is generally not directly impacted
by these activities (although frequently numerous), the overall environ-
mental impact rating is considered medium (Impacts to the vegetated littoral
areas (i.e., wetlands) is properly considered in the next section).
The major environmental concern to lake environments results from
chemical and subsequent biological modification of lakes rather than from
physical impacts. This is particularly true for lakes in the Northeast
where the natural buffering capacity is being affected by acid rain. There
does not appear to be a significant large scale problem associated with
physical impacts to lakes in this country. However, in specific instances
where lake environments are being altered significantly by such activities
as dredge spoil disposal, filling, and other activities, it may represent
an important local problem, particularly where the littoral zone provides
important aquatic habitat.
c. Freshwater Wetlands (Non-Tidal) [Buffered and Unbuffered Freshwater
Isolated Wetlands and Freshwater
Flowing Wetlands, in part]
Freshwater wetlands are similar to tidal wetlands but most importantly
do not receive the energy subsidy associated with the ebb and flow of the
tides. Examples include riparian wetlands along the shores of rivers and
streams, swamps, bogs, pocosins and fens.
Perhaps the most significant, large-scale hydrologic modification
occurring in this country today is the physical alteration and loss of
Inland, freshwater wetlands. Historic and current loss rates are tremendous
and have produced significant adverse environmental impacts to many regions
of the U.S. Ninety-seven percent of all wetland losses have occurred in
freshwater wetlands. The USFWS estimates that 11 million acres of freshwater
wetlands were lost from the mid-50's through the mid-70's and that the loss
rate continues at approximately 350,000-400,000 acres per year. Agricultural
conversions involving drainage, clearing, land leveling, groundwater pumping
and surface water diversion were responsible for 80 percent of the observed
conversion. Of the remainder, 8 percent resulted from the construction of
Impoundments, 6 percent from urbanization, and 6 percent from other causes
such as mining, forestry, and road construction. Fifty-three percent of
these conversions occurred in forested areas, such as bottomlands.
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-10-
Losses of freshwater wetlands have been observed nationwide. Less
than 5% of Iowa's natural wetlands remain and over 90% of the critical
central flyway wetlands of Nebraska's Rainwater Basin have been destroyed.
Only 20% of the original bottomland hardwood forests in the Lower Mississippi
Alluvial Plain remain. Other States with less than half of their original
freshwater wetlands include Michigan, Minnesota, Louisiana, North Dakota,
Connecticut, Ohio, Indiana and Illinois.
The trend of freshwater wetlands losses continues despite recent State
and Federal laws that are designed primarily to protect coastal wetlands.
Bottomland Hardwood wetlands of the Lower Mississippi Alluvial Plain are
being converted at an estimated 165,000 acres per year. Louisiana is losing
its forested wetlands at a rate of 87,000 acres per year. Pocosin wetlands
of North Carolina are being destroyed at a rate of 44,000 acres a year and
prairie potholes of the upper midwest are being lost at nearly 33,000 acres
a year. In each case, the wetlands are being lost primarily for agricultural
purposes.
An additional area of concern regarding hydrological modification
of freshwater wetlands is in tundra wetlands of Alaska's North Slope.
These pristine, highly valuable wetlands cover an area the size of
California and serve as critical breeding grounds for numerous species
of waterfowl each year. Oil and gas development activities proliferating
on the North Slope represent a significant threat to this important wildlife
habitat. Gravel roads, drill pads, production facilities, pipelines,
housing, power stations and most other facilities constructed on the fragile
tundra require placement on gravel insulation 3-5 feet thick. The necessary
mining and fill activities associated with this construction represent a
significant threat to extremely vulnerable tundra wetland ecosystems.
While predicting the future of the Nation's freshwater wetlands is
extremely difficult and complex, an examination of recent trends in
population, agriculture, and wetland protection provides some insight
into what can be expected. Population growth and distribution and
agricultural development greatly affect land-use patterns which impact
wetlands. Government's wetland protection efforts are key to preserving
wetland functions and values for today's public and future generations.
3. Terrestrial Systems
Although, by definition, this "Environmental Problem" has been
effectively limited to aquatic systems, two important points must be
noted.
a. In the natural world there are generally no sharp boundaries
between aquatic and terrestrial ecosystems. In many, if not the majority
of, cases aquatic systems are closely linked to adjacent terrestrial systems
through food chains, chemical cycles, the movement of animals, etc. Accord-
ingly impacts on one may have significant, perhaps profound, impacts on the
other. As an example, the elimination through filling or draining of a
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-11-
small wetland or pond in an arid area would eliminate the only source of
water for many terrestrial birds and mammals and, hence, eliminate their
local populations. A more subtle example would be the impact on a brown
bear population of reduction or loss of appropriate salmon habitat in a
stream or river. These sorts of effects will generally be most pronounced
in areas where fresh water is limiting (e.g., western riparian, desert,
barrier islands) or where there is a high degree of interspersion between
aquatic and terrestrial habitats) (e.g., tundra, intertldal zone, bottom-
land hardwood forests).
b. Significant physical changes to aquatic systems may produce
important secondary or indirect physical impacts on adjacent terrestrial
areas. These include inundation (from impoundment), flooding (from stream
modification or wetlands loss), loss "of water supply (from filling of
wetlands serving as groundwater recharge areas or stream modification),
or changes in micro-or meso-climate (from elimination of wetlands and/or
lakes). Similarly, certain hydrologlcal modifications such as Impoundment
can induce major human development which can have substantial Impact on
terrestrial ecosystems.
D. EPA Regulatory and Other Authorities
1. Clean Water Act
a. Section 404. Requires permits for the discharge of dredged material
("spoil") or upland-derived fill. Does not directly control drainage, timber-
ing, or other agricultural activities except where there is incidental dis-
charge of dredge or fill material. Program 1s fairly effective in controlling
regulated activities, particularly in coastal areas. As much as 75% of U.S.
wetlands loss may be outside the reach of the program.
b. Water Quality Management/Nonpoint Source programs. Principally
state/local programs that range from advisory-financial support to true
regulatory programs. Such programs, when effectively implemented, can
provide an important handle on certain activities (through water quality
certification) and can help control nonpoint source pollution with its
direct (slltration) and Indirect (necessity for dredging) Impacts.
c. Estuaries Program. Through comprehensive planning and financial
support, this program may come to have a marked effect on hydro!ogical
modifications, at least In the Nation's major estuaries.
2. Marine Protection, Research & Sanctuaries Act
Title 1 requires permits for ocean dumping of any pollutant. This is
the only such requirement and provides an effective regulatory handle on
discharges that may significantly change bottom contours and perhaps
currents.
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-12-
3. Clean Air Act
Section 309 authorizes EPA to review and comment on all federal projects
and actions, Including environmental assessments/Impact statements, policies,
regulations, and program plans. Through this activity EPA can significantly
Influence a wide variety of federal activities that Involve hydro!ogic modifi-
cations. Such activities range from the construction of highways and housing
developments to land management on all federal lands (forests, parks, BLM
lands, etc.)
4. National Environmental Policy Act
NEPA requires EPA, like any other federal agency, to evaluate the
environmental impacts of its actions and to seek to reduce those impacts.
As the result of a number of statutory and judicial exemptions, NEPA is
applied rather narrowly within EPA, but for those activities where 1t Is
applied—principally construction grants for sewage treatment plants and
NPDES permits for new source industries—it plays an important role in
avoiding or minimizing physical impacts to aquatic systems.
IV. Evaluation of Problem
Table 1 (page 13) presents a matrix which assigns a risk assessment
rating by comparing the four generalized ecological impacts with each of
the seven classes of aquatic systems. The matrix is derived by fitting
the Information summarized in Sections II and III of this paper into the
"Ecological Risk Model" developed by the workgroup. A consideration of
the matrix can provide a series of general conclusions regarding the
risks from physical alteration of aquatic systems; these are presented
in Section I.
Gregory E. Peck
Office of Wetlands Protection
David 6. Davis
Office of Federal Activities
November 20, 1986
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-13-
TABLE 1
MATRIX FOR PHYSICAL AQUATIC IMPACTS
Physical Habitat
Loss or Alteration
Addition of
Suspended Solids
(Turbidity)
Modification of
Water Levels
and Flow Regimes
Changes to Ambient
Water Parameters
(e.g. 03, C02,
temperature, light)
as a result of
physical alteration
Marine & Estuarlne Systems
Deep
Ocean
-
-
-
-
Shallow
Coastal
Waters
MR
HN
MR
LR
Estuaries
-HR
MR
HR
HR
Tidal
Wetlands
HN
MR
HN
HN
Freshwater Systems
Rivers
and
Streams
HE
HN
HR
HR
Lakes
HE
,
ME
ME
Non-
Tidal
Wetlands
HN
MR
HN
HN
Overall Impact
Rating
-
MR
HR
HN
HR
ME
HN
E - Ecosystem-Wide effects
R = Region-Wide Effects
N - Nationwide Effects
SCALE - H - High
M - Medium
L * Low
- « Imperceptible Ecological Effect
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-14-
Appendix
Information Sources
1. Darnell, R. M., et. al., 1976, Impacts of Construction Activities
in Wetlands of th~e" United States, U.S.E.P.A., Ecological Research
Series #EPA-600/3-76-045, 393 p.
2. Tiner, R. W., 1984, Wetlands of the United States: Current Status
and Recent Trends, USFWS, 59 p.
3. Cowardin, L. M., et. *\_., 1979, Classification of Wetlands and
Deepwater Habitats of the United States, USFWS Biological Services
Program, FWS/OBS-79/31, 103 >.
4. Wetzel, R. 6., 1975, Limnology, W. B. Saunders Co., 743 p.
5. Wetlands: Their Use and Regulation, 1984, U.S. Congress, Office of
Technology Assessment, OTA-0-206, 208 p.
6. Adamus, P. R. and L. T. Stockwell, 1983, A method for Wetland
Functional Assessment, FHWA-IP-82-23, 176 p.
7. Oceanography, 1971, Scientific American, W. H. Freeman Co., 417 p.
8. Section 404(b)(l) Guidelines, December 24, 1980, USEPA, 40 CFR
Part 230, Federal Register, Vol. 45, No. 249, p. 85336.
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SUMMARY
Hazardous Waste Sites - Active
(Subtitle C Waste Management Facilities)
Sources; 2,863 Treatment and Disposal Facilities for
RCRA Hazardous Wastes including thermal
treatment units, land disposal units,
recycling units, and other chemical, bio-
logical, or physical treatment units.
Exposure; Routine releases of particulates, toxics,
and/or nutrients to air, surface water,
and/or soil over facility lifetime.
Location; Facilities are located in a variety of
environmental settings—this problem area
includes onsite units, as well as com-
mercial units.
Ecosystem
Impacts; Localized impacts, potentially reversible over
a 10 year period.
Controls; In place or planned.
Workgroup
Ranking; Low
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HAZARDOUS WASTE SITES - ACTIVE
(Subtitle C Waste Management Facilities)
I. Description of Sources
Chemicals (some considered "exotic") at Subtitle C Waste
Management facilities may contribute directly and indirectly
to the degradation of ecosystems. They can directly effect
an ecosystem by being discharged into surface water via
aqueous waste treatment facilities, air pollution control
devices on incinerators and distillation facilities, and
runoff. Indirectly, they can enter surface water via groundwater
flowing beneath land disposal facilities.
In addition, contamination of soils from point and area
source emissions at some facility locations may also adversely
affect vulnerable plant and animal habitats. This may also
result from spills occurring during product/waste transfer.
Two other "ecological" or welfare problem areas are important,
but not within the current scope of OPPE's Comparative Risk
Project: the net loss of available land, and the net loss of
available groundwater that may be associated with hazardous waste
management activities.
The releases discussed above can result from either
routine or non-routine activities at waste management facilities.
These releases could increase the concentrations of various
chemicals in water, in air, and on land to levels that threaten
the productivity of receiving ecosystems, increasing the risk
to vulnerable species.
-1-
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The market for waste management facilities exists in a variety
of locations, irrespective of environmental setting. When
these facilities are built, efforts are usually made to assure
that technology and operating requirements will prevent ground-
water contamination regardless of setting. Facilities are
currently operating in almost every type of setting. Thus,
releases from hazardous waste management facilities, both
commercial and onsite, may affect both buffered and unbuffered
lakes and streams, forests, grasslands, marine and estuarine
ecosystems, and in a few cases, desert and tundra environments.
Ecological effects may occur in natural regions (not EPA
regions) or be limited to specific ecosystems. Even a catas-
trophic event at a waste management facility would not be expected
to produce impacts that are biospheric, or global, in scale.
II. Detailed Description of Sources
There are 2,863 active hazardous waste management facilities,
excluding storage facilities. These facilities can be broken
down into four broad categories: thermal treatment facilities,
land disposal facilities, solvent recovery facilities, and
other types of treatment facilities. The chart on the next
page shows for each broad treatment category the number of
facilities in that category, the major stress agents produced,
the fate of releases, duration of exposure and frequency of
exposure.
-2-
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SUBTITLE C WASTE MANAGEMENT FACILITIES
Facility Type fFacilities
Thermal
Treatment 298
Land Disposal
433
Recycling 846
Treatment 1286
Fate of Releases
Major
Stress Agent Air | Surface Water | Soil*
Particulates XXX
Toxics XXX
Toxics XXX
Toxics XXX
Toxics XXX
Nutrients X
Duration of Frequency of
Potential Potential
Exposure Exposure
Facility Routine
Lifetime
Facility Routine
Lifetime
Facility Routine
Lifetime
Facility Routine
Lifetime
*From air deposition and spills
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III. Evaluation of Ecological Risk
At this point in time, it is impossible to calculate the
absolute ecological risk attributable to hazardous waste manage-
ment facilities. However, a high, medium, or low ranking can
be assigned by estimating if the major stress agents (toxics,
particulates, and nutrients) could affect each of several
ecosystems and how severe any of the impacts might be. The
scoring for Subtitle C waste management facilities is shown
here:
Subtitle C Waste Management Facilities
Major Stress Agents: Toxics, Particulates, Nutrients
Fate of Releases: Air, Surface Water, Soil
Recovery Time for Impacts: Decades
Controls: In Place or Planned
Ecosystem Impact
Buffered Lake Low
Unbuffered Lake*** Medium
Buffered Stream Low
Unbuffered Stream*** Medium
Coastal Low
Ocean N/A
Estuary Low
Coniferous Forest Low
Deciduous Forest*** Low
Grassland Low
Desert Low
Tundra*** Medium
Wetland - Freshwater,
Isolated, Buffered*** Low
Wetland - Freshwater,
Isolated, Unbuffered*** Medium
Wetland - Freshwater,
Flowing Low
Wetland - Saltwater Low
***Most severe around thermal treatment facilities
OVERALL RANKING: Low
-4-
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Environmental Problem: Superfund Sites (#17)
Potential ecological effects at Superfund sites are
difficult to characterize because of lack of information.
Virtually all of the chemicals frequently found at Superfund
sites have acute or chronic effects on aquatic orqanisms.
However, the concentrations at which these chemical are
likely to occur and the concentrations to which aquatic
organisms are likely to be exposed are not known for most
sites. The likely effects of the complex mixtures of chemi-
cals typically found at sites also are not known.
It is likely that some ecological effects occur at all
sites because of the type of chemicals present, though effects
at most sites probably are minor. Information from a small
survey indicates that effects significant enough to affect
commercial and recreational activities may be present at
about 70 sites and significant ecological injuries may be
present at another 200 sites. In the absence of cleanup
efforts, the environment could be affected for a long time
because of the size of the sources of contamination and
because many of the chemicals involved are persistent and
bioaccumulative.
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Environmental Problem: 17, Superfund Sites
I. Description of Sources
A variety of contaminants at abandoned waste sites could have localized
effects in ecosystems, especially if such contaminants migrate to surface
water bodies through surface water runoff or through discharge of contaminated
ground water into surface water. Effects could be regional in scope depending
on the quantity and toxicity of the contaminants and the migration of such
cantaminants in surface water systems.
The Superfund program has been oriented to assessing and dealing with
threats to human health. Little attention has as yet been paid to assessing
the environmental effects of contaminants at Superfund sites,. In view of
the paucity of data on the extent of environmental impacts, only general
information will be provided that may give some indication of the severity
of ecological effects from abandoned waste sites.
II. Detailed Description of Sources, Releases, and Exposures
Currently there are^888 sites on the National Priority List (NPL). About
75 percent of these sites involve ground water contamination and about 45
percent involve surface water contamination. (Contaminated groundwater may
affect surface water bodies if the ground water eventually discharges to it
in high enough concentrations.) Another 23,000 sites are on the CERCLIS list
and are undergoing preliminary screening. As much as a guarter of such sites
eventually could be classified as NPL sites.
An indication of the frequency with which certain chemicals are present
at sites is provided in the table below. The 30 most frequently observed
chemical are listed along with the percentage of sites at which they were
observed (the data are based on a survey of about 540 sites).
Most Frequently Observed Chemicals (preliminary)
Chemical Name
TCE
Lead
Toluene
Chromium & Compounds
Benzene
Chloroform
PCBs
Tetrachlorethene
Trichloroethane
Zinc & compounds
Arsenic
Cadmium
Phenal
Ethylbenzene
Xylene
Frequency Chemical Name Freguency
55% Dichloroethylene 19
51 Copper & Compounds 19
43 Methylene Chloride 17
38 Cyanides 14
38 l,lDichloroethene 14
32 Mercury 13
29 Dichchorethane 13
27 Vinyl Chloride 12
26 1,2Dichlorethane 12
25 Chlorobenzene 12
24 Nickel & Compounds 11
24 Carbon Tetrachloride 11
22 Pentachlorophenal 10
20 Napthalene 9
20 Methyl ethyl ketone 7
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-2-
Virtually all of these chemicals have acute or chronic effects on
aquatic organisms. However, the concentrations with which these chemicals
are likely to occur at sites and the concentrations to which aquatic orqanisms
are likely to be exposed are not known for most sites. (We have not attempted
to tabulate concentration and exposure data for those sites that have been
sampled extensively.) The data also indicate that multiple chemicals are
present at sites. The likely combined effects of mixtures of such compounds
simply are not known.
No comprehensive study of ecological impacts around Superfund sites has
yet been conducted. The program is only now beginning efforts to undertake
bioassay assessments. Such tests are being pursued at a small number of
sites (New Bedford Harbor, Commencement Bay, and OMC). However, a survey
was conducted by OPA to determine the potential for natural resources injurv
around NPL sites (277 sites were contained in the survey). Natural resource
injury was defined to exclude injuries to ground water, drinking water supplies,
and air but to include all other natural resources, including surface water,
wetlands, fisheries, biota, and wildlife.
Based on the survey results, about 6 percent of NPL sites are likely to
have significant natural resource injuries—commercial effects (primarily to
fisheries) or recreational effects large enough bring damage suits. Another
16 percent may have some possibility of injury to natural resources. The
frequency with which potential ecological injuries were mention for the
latter sites was as follows: surface water — 90%; wetland — 37%; fisheries
— 55%; and other (land, forests, endangered species, marine mammals, biota,
and wilderness) — 32%. About a third more sites with the potential for
natural resouce injury may come from non-NPL sites. Thus, about 70 sites
would have significant natural resource injuries and significant ecological
effects may be present at another 200 sites.
Some examples of sites at which there could be significant ecological
impacts are as follows:
CMC; Waukegan, IL. — substantial PCB contamination of harbor and
river leading to Lake Michigan;
GE; Hudson River — significant amounts of PCBs in river sediments;
Whitewood Creek, SD — aquatic damage due to metals contamination from
and Phelps Dodge, A2 mining wates;
Nashua,_NH — ground water contaminated with volatile organics
discharging into swamp and nearby river;
Mottalo, NH — swamps, creek and river adjacent to site
Waste Industries, SC — estuarine swamp land and nesting birds threatened
by leaking municipal waste site;
New Bedford, Habor — significant PCB contanination of harbor; and
Hyde Park Landfill — site contains over 1 ton of dioxins; low concen-
trations in ground water discharging to the
Niagra river and thence to Lake Ontario.
Unfortunately, studies are not available to assess the actual effects of
contamination on the ecology at these sites. For instance, in New Bedford
-------
Harbor high levels of PCBs have been found in the tissues' of marine organisms,
but no information is yet available on whether the community structure,
reproductive cycles of longevity of species has been affected.
III. Evaluation of the Problem
It is difficult to characterize potential ecological effects at Super-fund
sites because of the lack of data. Given the nature of the chemicals present
at such sites, it is likely that some ecological effects occur at all sites,
though at most sites they probably are minor. However, based on very prelim-
inary information effects significant enough to affect conmerical and recrea-
tional activities may be present at about 70 sites and significant ecological
injuries may be present at another 200 sites. Many of the chemicals involved
are persistent and bioaccumulative and could affect the environment for
extended periods of time.
Sources of information:
Putnam, Hayes & Partlett, Inc., Assessment of the Potential for Natural
Resource Claims at Hazardous Waste Sites, Sept. 1985
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SUMMARY
Jf
Municipal "Non -Hazardous" Waste Sites - Active
(Subtitle D Municipal Waste Management Facilities)
Sources:
Exposure;
Location:
Ecosystem
Impacts;
16,636 Treatment and Disposal Facilities for
RCRA "Non-Hazardous" Municipal Wastes including
thermal treatment units, landfills, surface impound-
ments and land application units.
Routine releases of particulates, toxics,
BOD, microbes, PCDFs, PCDDs, and/or nutrients to air,
surface water, and/or soil over facility lifetime.
Facilities are located in many locations, encompassing
many different environmental settings.
Localized impacts, potentially reversible over
a 10 year period.
Controls: Not much.
Workgroup
Ranking;
Medium
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MUNICIPAL "NON-HAZARDOUS" WASTE SITES - ACTIVE
(Subtitle D Municipal Waste Management Facilities)
I. Description of Sources
Chemicals from municipal waste management facilities may
contribute directly and indirectly to the degradation of
surrounding ecosystems primarily via surface water and air
routes. They can be directly discharged via surface water
runoff and through covolatilization during methane generation
and emission. Indirectly, they can enter surface water via
groundwater flowing beneath land disposal facilities.
Another potential problem area is the use of municipal
waste combustion fly ash for fill in surface water bodies.
It is not clear how often this takes place, but some ash has
been found to contain polychlorinated dibenzofurans and dioxins
(PCDFs and PCDDs). These substances are thought to be highly
toxic to aquatic life.
Two other "ecological" or welfare problem areas are
important, but not within the current scope of OPPE's Comparative
Risk Project: the net loss of available land and the net loss
of available groundwater that may be associated with waste
management activities.
The releases discussed here can result from routine activities
at municipal waste management facilities. These releases could
increase the concentrations of various chemicals in water and
-1-
-------
on land to levels that threaten the productivity of receiving
ecosystems, increasing the risk to vulnerable species.
Municipal waste management facilities of some type are located
in virtually every community in the nation, in every type of envi-
ronmental setting. When these facilities are built, efforts are
made to assure that technology and operating requirements will
prevent groundwater contamination regardless of setting. Facilities
are currently operating in almost every type of setting. Thus,
releases from municipal waste management facilities may affect
both buffered and unbuffered lakes and streams, forests, grass-
lands, marine and estuarine ecosystems, and in desert and tundra
environments.
Ecological effects may occur in natural regions (not EPA
administrative regions) or may be limited to specific ecosystems.
Even a catastrophic event at a waste management facility would
not be expected to produce impacts that are biospheric, or
global, in scale.
II. Detailed Description of Sources
There are 16,636 active municipal waste management facilities,
These facilities can be broken down into four broad categories:
landfills, surface impoundments, land application units, and
incinerators. The chart on the next page shows for each broad
treatment category the number of facilities in that category,
the major stress agents produced, the fate of releases, duration
of exposure and frequency of exposure.
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SUBTITLE D MUNICIPAL FACILITIES
Facility Type #Facilities
Landfills 9,280
Surface Im-
poundments 2,426
Land Applica-
tion Units 11,937
Incinerators 110
Major
i Stress Agents
BOD
Nutrients
Microbes
Toxics
BOD
Nutrients
Microbes
Toxics
BOD
Microbes
Toxics
Nutrients
Particulates
Toxics
PCDF,PCDD
Fate of Releases
Air | Surface Water | Soil
X
X
X
XX X
X
X
X
XX X
XX X*
XX X
XX X
XX X
Duration of Frequency of
Potential Potential
Exposure Exposure
Facility Routine
Lifetime
Facility Routine
Lifetime
Facility Routine
Lifetime
Facility Routine
Lifetime
*From direct application as opposed to air deposition and spills-.
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Ill. Evaluation of Ecological Risk
At this point in time, it is impossible to calculate the
absolute ecological risk attributable to municipal waste management
facilities. However, a high, medium or low ranking can be
assigned by estimating if the major stress agents (BOD, nutrients,
microbes, toxics, particulates, PCDFs and PCDDs) could affect
each of several ecosystems and how severe any of the impacts
might be. The scoring for Subtitle D municipal waste management
facilities is shown here:
Subtitle D Municipal Waste Management Facilities
Major Stress Agents: BOD, nutrients, microbes, toxics
particulates, PCDFs and PCDDs
Fate of Releases: Air, Surface Water, Soil
Recovery Time for Impacts: Years
Controls: Not Very Controlled
Ecosystem Impact
Buffered Lake Medium
Unbuffered Lake* Medium
Buffered Stream Medium
Unbuffered Stream* Medium
Coastal Low
Ocean N/A
Estuary Low
Coniferous Forest Low
Deciduous Forest* Medium
Grassland Medium
Desert Medium
Tundra* High
Wetland - Freshwater,
Isolated, Buffered* Medium
Wetland - Freshwater,
Isolated, Unbuffered* High
Wetland - Freshwater,
Flowing Low
Wetland - Saltwater Medium
*Most severe around municipal waste incinerators
OVERALL RANKING: Medium
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SUMMARY
Industrial "Non-Hazardous" Waste Sites - Active
(Subtitle D Industrial Waste Management Facilities)
Sources; 193,484 Treatment and Disposal Facilities for
RCRA "Non-Hazardous" Wastes including thermal
treatment units, landfills, surface impound-
ments and land application units.
Exposure; Routine releases of particulates, toxics,
BOD, and/or nutrients to air, surface water,
and/or soil over facility lifetime.
Location; Facilities are located in many locations,
encompassing many different environmental settings,
and many times several are located in the same
area.
Ecosystem
Impacts;
Workgroup
Ranking;
Localized impacts, potentially reversible over
a 10 year period.
Controls: Some
Medium
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INDUSTRIAL "NON-HAZARDOUS" WASTE SITES - ACTIVE
(Subtitle D Industrial Waste Management Facilities)
I. Description of Sources
Chemicals from non-hazardous industrial waste management
facilities may contribute directly and indirectly to the
degradation of surrounding ecosystems primarily via surface
water and air routes. They can be directly discharged from
the solid waste management unit and via surface runoff.
Indirectly, they enter surface water via groundwater flowing
beneath land disposal facilities.
In addition, contamination of soils from point and area
source air emissions at some facility locations may also adversely
affect vulnerable plant and animal habitats. This may also
result from spills occurring during product/waste transfer.
Two other "ecological" or welfare problem areas are
important, but not within the current scope of OPPE's
Comparative Risk Project: the net loss of available land and
the net loss of availabl-e groundwater that may result from
industrial waste management activities.
The releases discussed here can result from both routine
and non-routine activities at waste management facilities.
These releases could increase the concentrations of various
chemicals in water and on land to levels that threaten the
productivity of recieving ecosystems, increasing the risk to
vulnerable species.
Industrial waste management facilities exist at many
locations, irrespective of environmental setting. When
-------
facilities are built, it is hoped that efforts will be made to
assure that technology and operating requirements will prevent
groundwater contamination regardless of setting. Facilities
currently operate wherever industry operates, in almost every
type of setting. Thus, releases from industrial waste management
facilities may affect both buffered and unbuffered lakes and
streams, forests, grasslands, marine and estuaring ecosystems,
and in a few cases, desert and tundra environments.
Ecological effects may occur in natural regions (not EPA
administrative regions) or be limited to specific ecosystems.
Even a catastrophic event at a waste management facility would
not be expected to produce impacts that are biospheric, or
global, in scale.
II. Detailed Description of Sources
There are 193,484 active industrial waste management
facilities. These facilities can be broken down into four
broad categories: landfills, surface impoundments, land
application units, and incinerators. The chart on the next
page shows for each broad treatment category the number of
facilities in that category, the major stress agents produced,
the fate of releases, duration of exposure and frequency of
exposure.
-------
SUBTITLE D INDUSTRIAL FACILITIES
Facility Type fFacilities
Major
Stress Agents
Fate of Releases
Air | Surface Water | Soil
Duration Frequency
of of
Exposure Exposure
Landfill 7, 136
Surface 189, 396
Impoundments
Land Applica- 6,952
tion Units
Incinerators UNKNOWN
Toxics X
BOD
Nutrients
Toxics X
BOD
Nutrients
Toxics X
Toxics X
Particulates X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X*
X
X
Facility Routine
Lifetime
Facility Routine
Lifetime
Facility Routine
Lifetime
Facility Routine
Lifetime
*From direct application as opposed to air deposition or spills.
-------
Ill. Evaluation of Ecological Risk
At this point in time, it is impossible to calculate the
absolute ecological risk attributable to industrial waste manage-
ment facilities. However, a high, medium or low ranking can
be assigned by estimating if the major stress agents (BOD,
nutrients, toxics, particulates) could affect each of several
ecosystems and how severe any of the impacts might be. The
scoring for Subtitle D industrial waste management facilities
is shown here:
Subtitle D Industrial Waste Management Facilities
Major Stress Agents: BOD, nutrients, toxics, particulates,
Fate of Releases: Air, Surface Water, Soil
Recovery Time for Impacts: Years
Controls: Some Controls
Ecosystem Impact
Buffered Lake Low
Unbuffered Lake* Medium
Buffered Stream Low
Unbuffered Stream* Medium
Coastal Low
Ocean N/A
Estuary Low
Coniferous Forest Low
Deciduous Forest* Medium
Grassland Medium
Desert Low
Tundra* Low
Wetland - Freshwater,
Isolated, Buffered* Low
Wetland - Freshwater,
Isolated, Unbuffered* Medium
Wetland - Freshwater,
Flowing Low
Wetland - Saltwater Low
*Most severe around industrial waste incinerators
OVERALL RANKING: Medium
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Resource Extraction, Beneficiation and Wastes -^%&
Summary
Resource extraction has been ranked third along with the
general area of habitat modification. This is due not only to the
national distribution of the problems, but also the irreversible
qualities of disturbances and their associated pollutants .
Geographical Extent:
Acid mine drainage is a result of the oxidation of metalic
pyrites, which are compounds of sulfur and are ubiquitous as well
as highly reactive chemically. It is most widely spread in the
coal fields in the states east of the Mississippi. However, it is
not unknown in the mining areas of the Rockies and in California
and Alaska.
Oil and gas drilling has the greatest impact in the wetland
areas of the Gulf Coast states and in Alaska as well as along the
California coast. ' Some problems have also been recognized in land,
especially where salt discharges to streams and wetlands have
occurred in Appalachia. In addition, some hazardous wastes are
associated with oil and gas drilling operations.
Non-energy minerals extraction problems are identified with
copper mining in Arizona, Utah, and Montana. Iron mining also has
caused some problems, mainly in the Lake Superior area. Phosphorus
mining, mostly in Flordia (with a little in North Carolina and New
Jersey) is expected to disturb close to 20,000 areas within the
next 20 to 50 years.
Characteristics;
Acid mine drainage results in lowered pH of streams and high
levels of dissolved minerals, especially iron and managanese. In
addition, extraction, beneficiation, and reclamation result in the
release of suspended solids.
Oil and gas drilling result in drastic hydrologic disturbances
due to the canals and causeways that are build to access drilling
sites. Drilling also produces muds and rock fines that have water
pollutant impacts.
Non-energy minerals extraction generally is characterized by
habitat losses, air pollution, and the release of suspended and
dissolved solids to waterways. Waste byproducts are sometimes
-------
caustic, but are always voluminous, making disposal a landfill
problem of large magnitude in acreage alone.
Effects/Impacts;
Acid mine drainage impacts aquatic, wetland, and terrestrial
habitats. Few if any streams have returned to pre-mine quality
after mining is done, Wetlands and terrestrial habitats are both
chemically and physically altered by mining activities and also
never return to their pre-mine quality.
Oil and gas drilling results in the annual loss of about 50,000
acreas of coastal Wetlands. Runoff patterns are irreversibly
altered so that habitats are permanently changed. These losses are
a direct result of canal building and channelization. Dredge and
fill operations also release dissolved and suspended solids as
pollutants.
Non-energy minerals extraction involve the commitment of large
areas of land, usually terrestrial habitat, to mining and tailinge
disposal activities. In addition, beneficiation results in wide
areas imapcted by air emissions. Dissolved suspended solids are
the major water pollutants and cannot be completely controlled
under current technology, with the result that many thousands of
miles of streams and acreas of wetlands are permanently impacted.
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Abstract
The ecological impacts of resource extraction are felt in all four major
ecological systems enumerated by the ERG Workshop and the Ecological Effects
Matrix. Impacts are attributable to the nine major stress agents listed be-
low with variations among the ecosystems with regard to the stress agents.
Stress Agents:
0 Acid Mine Drainage ° Solids
Mine spoil
0 Toxic Inorganic Chemicals Beneficiation & Refining Wastes
Use-Byproducts
0 Nutrients
0 Habitat Alteration
0 Turbidity Canals
Causeways
0 Oils Channelization & Dradging
Machinery ° Groundwater
Spills Disruption
Contamination
Impacts to Ecqsysterns,;
0 Acid mine drainage impacts freshwater, terrestrial, and wetland ecosystems,
but is of negligible importance in marine/estuarine systems.
0 Toxic inorganic chemicals are important in freshwater and terrestrial eco-
systems, but appear to be of only moderate importance in wetlands and marine,
and estuarine systems.
0 Nutrients have high impacts in freshwater systems, but are generally of
moderate importance in others.
0 Turbidity is mainly a problem in freshwater systems, but only of moderate
importance in marine/estuarine and, apparently, wetland habitats; it is of
negligible importance in terrestrial ecosystems.
0 Oils appear to be a major problem only in marine/estuarine systems.
0 Solids are a problem in freshwater, wetlands, and terrestrial systems, but
only of moderate importance in marine/estuarine systems.
0 Habitat modification is considered to be a serious matter in all systems.
0 Groundwater is seriously impacted only in freshwater and terrestrial sys-
tems and is moderately affected in wetland systems; it is neglibly impacted
in the marine/estuarine systems.
It is estimated that more than 15,000 NPDES permits and about 1000 CWA Sect.
10/404 dredge and fill permits, associated with resource extraction, are in effect.
-------
Introduction:
The United States is blessed with an abundance of natural resources which have
contributed to the Nation's economic well being. However, extraction, refinement and
consumption of these resources have also resulted in some of the most severe ecological
problems of the country. Ecological degradation resulting from resource extraction is
perhaps the most widespread form of pollution in an industrialized society. Extrac-
tion and processing of natural resources have resulted in millions of acres of surface
lands permanently scarred as well as disruption and degradation of surface and under-
ground hydrological resources. Since 1939, surface disruption for mining has affected
an area equal to 2/3 the size of Connecticut. Few activities of man have the potential
for adverse impacts to the ecosystem as that represented by resource extraction. The
following are three areas of major concern:
0 Air pollution from refining ores and crude oils.
0 Land scarred by mining and reclamation methods as well as from waste products
(tailings) from refinement.
0 Water pollution by dissolved and suspended solids from extraction, refining,
tailings disposal, and reclamation.
A wide range of aquatic, raarine/estuarine, and terrestrial ecological impacts
are still being identified. Habitat fragmentation caused by oil and gas extraction
in Alaska and the Gulf States is one example. Groundwater disruption and degradation
from resource extraction is also widespread.
In all examples of resource extraction, disturbance of the existing geological
equilibrium results in ecological impacts that are difficult to evaluate in terms of
long term costs. However, aggregate figures demonstrate lands lost to production,
terrestrial habitat, and miles of streams degraded. Full economic and ecological
analyses, however, have yet to be carried out.
Ta.ble 1: Summary Statistics on Resource Extraction.
Resource
Commodity
Category
Metals:
Non-metals :
Energy:
Coal:
Gas:
Oil:
Commodity
Surface*
1700
2680
482.7
Retrieved by Extraction
Method
Deep* Drilling/Pumping
88
78
301.2
19.0 million Cu. Ft.
24.5 million BB1 .
NPDES Permits
Coal:
Ore Mining:
Assoc. Ind.:
10,375
515
4288
Total
15,168
*Million Short Tons
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2
Energy Resources
Four states lead the Nation in oil and gas production:
1 Texas 3 Louisiana
2 Alaska A California
These four states produce more than three-quarters of the Nation's total. The
same four states rank in the top of gas-producing states, but produce only about
half of the total. Again, Texas ranks first, but in this case Louisiana is
second with California third and Alaska fourth.
The most productive coal Regions are III and VIII with levels of about 213
and 190 hundred million tons respectively per year. Region IV is third with an
annual production of about 170 million and Region V is fourth with a production of
about 110 million tons. Surface raining out-produces deep mining: about 480 million
tons come from surface mines while about 300 million tons are deep mined.
Non-energy Resources
The Minerals Yearbook covers all other mineable resources, but for our purposes
here we have limited our interest to copper, iron, and phosphorus. These appear to
be the most representative of the characteristic problems associated with mining.
Copper mines are located in 14 states with Arizona leading all in production
at 68% of the total. When added with the production of Utah, New Mexico, and Mon-
tana, 95% of the Nation's total is represented. Most of the production is from 25
surface mines (84%).
With regard for iron mining, 92% is from mines in the Lake Superior area, lo-
cated specifically in Minnesota, Michigan, and Wisconsin; thirteen mines are located
in Minnesota. Some production also takes place in California, Utah, Wyoming, and
Missouri.
Since 18 open pit phosphate mines are located in Florida, this state was exclu-
sively used for this discussion. North Carolina is the only other state with phos-
sphate rock mine of any size. Between them, they produce 87% of the Nation's total.
Impacts from mining and processing phosphate are found throughout the environmental
media. The ore is taken from surface mines as deep as 50 feet, covering thousands
of acres.
About 700,000 tons of peat are mined every year in the Nation, from nearly
100 active mines. The states leading in production are Michigan, Florida, Indiana,
and Illinois. Reed-sedge peat accounts for 61% of the total, with humus next at
20%. Hypnum and sphagnum are lowest at 5% and 3% respectively. The highest demands
for peat is for potting soil ingredient, soil conditioner, and general nursery uses.
Little if any is used as a source of energy, though that was considered several
years ago at the height of the energy crisis.
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F Igure 1
Natural gas and Petroleum fields and Peat lands
Natural gas
and petroleum
fields
More natural gas and oil are consumed
than any other fuel. CM accounts tor
roughly half ol aN energy used and natural
gas accounts for a fourth. Both are easy
to transport and are generally relatively
clean-burning fuels.
CM and natural gas fields are located
primarily in Texas. Oklahoma, and Loui-
siana and in the outer continental shelf of
the Atlantic. Gulf. Pacific, and Alaskan
coasts. In 1977. about 10% of oil produc-
tion was in the outer continental shelf.
In 1977. 2.5 million acres in the outer
continental shelf were offered for leasing.
Of that, oil companies have leased 1.1
million acres. In a lease sale, the Federal
Government sells into private ownershp
the right to explore, develop, and produce
oil and gas. The buyer then explores for oil
and gas. If any is found, the buyer pays a
royalty based on the amount produced.
-------
Figure- 2
Coal is the Nation's most abundant fossil
fuel, making up 95% of fossil fuel-re-
serves. Coal is also one of the most en-
vironmentally damaging fuels, emitting fine
particulates. hydrocarbons, nitrogen and
sulfur oxides, and trace metals when it
burns without control.
Anthracite is the hardest and has the
highest heat content of the coals Reserves
of bituminous coal are the most abundant.
Lignite and subbitummous coals are lowest
in sulfur content.
Coal reserves in the East are generally
deeper than those in the West, where they
can be surface mined. In the West, re-
clamation of disturbed land is made dif-
ficult by the shortage of water.
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Impact Evaluation
The work group decided upon a system for evaluating various problems based
upon the extent of impact. For example, ozone is considered to be a biosphere
problem (worldwide in impact) while a regional problem is considered to be one
where the impacts merly cross ecological boundaries and are not world-threatening.
The category of resource extraction is almost exclusively regional in nature.
Even when limited to a specific site, nearly all activities spill over into neigh-
boring environmental media.
Impacts are discussed in a general way, based upon the four major biomes as
determined by the Work Group. However, We think that impacts and stress agents
are often broader than the arbitrary categories and this constraint has limited
the final picture to some degree. For example, habitat fragmentation is a problem
in all categories of resource extraction and, though it is mentioned often in the
discussions below, it has broader implications as a stress agent than the some of
the other stress agents. In spite of this, we have remained within the boundaries
of the committee's rules, by including habitat fragmentation as part of the ecosystem
discussions.
Freshwater Ecosystems;
Both deep and surface coal mines have environmental implications that involve
impacts to aquatic ecosystems. Surface mining operations have a wider range of im-
pacts than ^eep raining, but the latter has impacts upon underground water patterns
and quality that is difficult to define and control. An example of this is found
in the anthracite area of Region III. The beds lie at a steep angle which, when
exposed for mining and left unreclaimed, results in conditions that allow water in-
filtration into the workings. This, in turn, results in continuous production and
"flushing out" of acid mine drainage. Potentially, a vast reservoir of low pH
water containing high quantities of TDS lies in the ground occupying the abandoned
workings. This water forms a "mine pool" that poses a threat to stream and river
ecosystems by acid water flowing from natural seeps and manmade boreholes with
polluted groundwater as the source.
The geochemistry of Appalach'ia contains large quantities of pyritic minerals
which oxidize into the chemicals that cause acid mine drainage. Over 10,000 miles
of streams continue to be degraded in Appalachia ( Environmental problems also
arise from processing and the by-products of associated operations). Tailings
from beneficiation plants contain toxic metals and compounds that are released
through the mechanism of acid dissolution. This is a wide spread problem in nearly
all coal mining areas east of the Mississippi and is not unknown in other areas
where pyritic forms of sulfur are located; metallic pyrites are .among the most
common minerals worldwide. Put simply, oxidation of pyritic minerals produces
sulfuric acid and a precipitate of iron hydroxide. The low pH is deadly to bio-
logical systems and the precipitate destroys benthic habitat.
The "area" mines of the midwest expose thousands of acres of coal and in doing
so act as a drain for aquifers that are the stabilizing factor in water table main-
tenance. The disrupted aquifers in the Midwest carry adverse implications for
streams, rivers, and lakes through alteration of groundwater as a source.
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In all mining and drilling extraction processes, geochemicals are produced
that, once exposed to the air, are readily oxidized, and become water soluble poll-
utants. Regulations currently require treatment for these waters prior to discharge
and as a result of this treatment, a sludge Is produced that requires disposal. It
is a relatively innocuous solid, but almost always poses a disposal problem to the
permittee. The regulatory aspects are discussed later in this presentation.
Gas and oil exploration and drilling are a cause of habitat fragmentation.
In the Gulf states, canals and channelized streams used for barging equipment and
product act as "funnels" for saltwater intrusion and the seaward translocation
of freshwater. They cause salinity and flow changes in the hydrologic regime that
impact resident populations of fish and fishfood organisms.
Marinje and Estuarine:
The marine and estuarine impacts of offshore drilling for gas and oil occur
throughout the water column and, in the event of spills, are widespread. However,
the greatest impacts of off-shore extraction are felt on the benthic and nektonic
populations. Heavy components of oil sink to the bottom, interfering with oxygen
exchange, while lighter fractions tend to remain in the surface waters. PAH's (poly-
cyclic aromat.ic hydrocarbons) in oils impact both surface and benthic organisms.
Examples of these compounds are benzo[a]anthracene, phenanthrene, and anthracene.
Their impacts are manifested by both inhibited and accelerated growth, interference
with photosynthesis, alteration of embryo development, altered osmoregulation,
carcinogenesis, rautagenesis, and teratogenesis. In addition, impact is also a re-
sult of rock cuttings and drilling muds whereby the ecosystem of both the water
column and benthos are impaired. The inputs are continuous and contain several
deleterious lubricant and cleansing compounds used in the drilling and extraction
processes.
Estuarine and close offshore drilling sites tend to exhibit a broader spectrum
of impacts than the marine environment. Near-shore zones in the Gulf are well known
for their ecological productivity as well as for their sensitivity to the foreign
chemicals produced in drilling operations. In Alaska, causeways that are extended
across the land and into the sea interrupt "corridors" that are used by anadromous
fish heading for fresh waters to spawn and also fragment the nesting and feeding
habitats of shore birds.
Wetlands;
While open water ecosystems are sensitive to drilling for oil and gas and to
oil spills, the on-shore exploration and extraction operations are the more damaging,
especially in the fresh and saltwater wetland areas of the Gulf states and Alaska.
Mining and recreational development of peat bogs is also of major importance re-
sulting in habitat fragmentation.
The major gas and oil areas of both Alaska and the Gulf states are located in
the extensive marshes of their coastal zones. These areas are among the most heavily
stressed of all the ecosystems. In addition, contaminated water from the excess
pumpage often contains hazardous substances and is discharged into the wetlands
along with other contaminants used to facilitate the drilling and pumping. In
some cases, they are disposed of through underground injection. (See also the
chapter on hazardous wastes.)
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Hydrologic changes associated with canals and channelized streams to accomodate
barges impact the marsh habitat. These changes result in stressed vegetation and
subsequent loss of the substrate maintenance capacity of the marsh plants. Erosion
follows, allowing shallow and increasingly large salt and brackish lakes to form.
They also allow for enhanced seaward flows of land runoff, carrying the nutrients to
sea rather than allowing them to be deposited in marshes where they normally end up.
Peat bogs also fall into the category of fragile lands that, once disturbed,
cannot be restored using currently available technology. Exploitation for their
resources always results in the complete destruction of the habitat. In addition,
they are often the preferred habitat of threatened and endangered species as well
as selective habitats. For example, peat bogs in Pennsylvania are important to
the black bear and peat mining followed by recreational development has had a severe
impact upon their populations. Peat bogs are especially attractive to them because
they offer both refuge and a good dependable food supply.
Sphagnum bogs are the source of peat and have shown promise in treating some
kinds of wastes. While their value and limitations in this regard are still being
evaluated, it is known that they are often unaffected by acid mine drainage and
even effectively treat it through both their chemical and biological systems.
In general, wetlands are adversely affected by disruption 6f the hydrologic
regime- as a result of resource extraction and can also be overwhelmed by excesses
of suspended and non-settleable solids. They can also be impacted by the discharges
that are in compliance with effluent guidlines. While investigation is still under-
way, it appears that the acidophilous plants have difficulty surviving discharges
of coal mining effluent in the 6 to 9 pH range.
Finally, wetlands are also adversely impacted by the brine effluents of wells
tapping resources below the geological salt zone. This is an especially serious
problem in the Allegheny Mountains of Pennsylvania.
Terrestrial;
In Alaska, roads and facilities constructed to accomodate the equipment needs
of the oil and gas industry disrupt the nesting and feeding ranges of migratory
waterfowl. Off-road vehicles used for transporting equipment compress the surface
with their tracks and disrupt vegetative continuity. The terrestrial ecosystem is
also disrupted by "reserve pits" where drilling wastes are stored. These pits leak
their holdings into the surface as well as ground water.
With respect to coal mining, long terra problems are caused by abandoned lands
of Appalachia where over 600,000 acres of abandoned surface mines are conservatively
estimated as still unreclaimed. In the West, lands left either scarred or stacked
high with the waste by-products of mining appear to be the problems of greatest con-
cern. Losses of land use are compounded by the toxic potential of the spoil. While
the toxicity of the spoil is low, the sheer size of these areas is so large that the
ecological impacts are large. A study of such an area in Utah will encompass an
area of about 200 square miles. Both the mining operation and its associated accumu-
lation of waste products are further examples of habitat loss and fragmentation.
Diversity and productivity are greatly reduced as a result of mining even when the
disturbed lands are restored.
-------
Table 2
Status of Land Disturbed by Surface Mining in the United States as of July 1, 1977 by States.3
Land Needing Reclamation (acres; dashes indicate none)
Reclamation not required
Reclamation required by law
by any law
State
Alabama
*Alaska
'Arizona
Arkansas . ...
Cal i fornia
Caribbean Area. .
Colorado
•Connecticut
Del aware
Florida
Georgia
Hawa i i
Illinois
Indiana . ...
I owa . .
Kansas
Kentucky
"Louisiana
Maine •
Maryl and . . .
•Massachusetts. .
Michi qan
Mi nnesota . . .
Mi ssi ssippi . .
Missouri
Montana
•Nebraska
•Nevada
•New Hampshire. .
•New Jersey
New Mexico
New Vork
North Carolina. .
North Dakota
Ohio
Okl ahoma
Pennsylvania
•Rhode Island...
South Carolina. .
South Dakota. . .
Tennessee . ...
Utah
Washington
West Virginia...
Wisconsin
Wyonti ng
TOTAL 1
Coal
mines
72,292
2,700
400
5,623
10
7,089
1,680
118,711
25,882
13,997
41,256
101,637
6,412
142
70,688
1,955
22
1.050
196.709
36.118
240,000
890
29,583
3,310
635
23,724
48
84,868
9,657
,097,088
Sand
and
gravel
16,611
4,300
6,400
21,483
7,970
2,550
8,334
16,740
2.912
11,162
3.353
15
5,100
20,330
11,875
10,147
11,150
980
37,324
28,833
7,430
32,041
39,424
30,047
45,066
4,473
4,655
17,969
1,221
12,725
24,610
11,860
30,917
11,908
2,010
22.621
6,659
3,521
11,000
2,592
9,065
10,153
4,950
152,457
3,999
3,877
3,788
9,701
4,554
41,607
3,673
799,042
Other
mined
areas
19,929
4,000
60.900
11,479
80,998
1,000
15,861
787
63
235,700
24,008
115
1,500
14,192
6,522
6,421
10,159
4,712
2,549
2', 0.7 5
1,181
10.330
23.422
44,801
7,821
28,187
18,340
4,029
2,555
417
5,570
1,806
19,251
4,792
200
18,923
14,105
17,568
20,500
2,128
5,259
2,305
37.104
4,414
2,078
1.251
8.174
995
7,555
12.376
830,407
Coal
mines
34,807
2,859
500
1,195
764
40,899
74,581
341
815
154,218
5,703
8,772
4.766
3,709
6,725
77,050
6,298
3
60,000
3,127
3,725
133
8,222
1.190
7.658
62,028
570,088
Sand
and
gravel
5,498
20
17,642
11,672
3.365
4.623
18,200
8.582
4.176
8.457
3.634
2,299
2,293
9,741
15,662
12,444
1.046
4.492
1,057
15,979
7,096
16,659
2,766
6,814
iS.OOO
4,395
6,826
810
6,289
4,637
377
3,929
11.822
11,884
7,665
257,851
Other
mined
areas
6,252
1,592
51,316
6.513
20.922
13,772
3,500
4,557
1,894
9,638
3,980
2,780
923
1,734
4,072
7,891
6,055
6,598
26,072
5.037
3,909
8,427
4,110
1,538
25,000
3.194
695
1,135
4,989
10,216
60
2,003
1.073
2,865
12,787
267,097
Land not
requiring
reclamation
85,673
4.000
121.800
9,449
59,061
710
14.023
4.590
1.498
61,266
23,247
2,500
88,860
64,711
10,519
20,117
154.495
10.467
6,794
19,824
11,750
27.600
66,919
14,415
22.051
12,528
11.005
1.953
547
8,263
2,207
18,477
7,000
38.595
190.578
16,255
7,387
250,000
3,470
9,815
7,149
104.596
48,456
7.521
1,536
70,060
10.245
137.105
21.605
5,511
1.898,203 5
Total
land
disturbed
241.062
15.000
189,500
52,505
217,497
4.260
64,687
22,117
4,473
332,415
71.447
130
30,800
296,131
189,641
59,520
91,109
421,121
50,340
40.9'18
52,025
54,121
110,322
162.102
68.202
141.272
53,334
33,003
5,729
13,689
38,443
46.733
89,661
34,705
48.580
530.967
86.311
36,831
621,500
6,062
28,597
30,972
146,506
256.330
31.555
7.928
112,977
42,253
235,180
85,516
113,697
,719.776
«_/ From USDA, 1980. Soil and Water Resource Conservation Act: Appraisal 80. Review Draft. Part I.
* No State law when survey completed; therefore, no reclamation by law.
-------
Severity Evaluation
The formula below has been used to evaluate the severity of "impact/risk"
associated with resource extraction and to arrive at a relative ranking of them:
Ge (I + F + D) = R
Ge is geographical extent: miles, acres, volumes, etc.
I is intensity: severity of impacts
F is frequency: coefficient of recurrence
D is duration: recovery time
R is Impact/Risk: factor applicable to effects
Since the impact/risk is felt by the biome and that biome can be viewed as
a geographical unit or area, all other factors (i.e., Intensity, "I", Frequency,
"F", and Duration, "D") affect it. Thus, mathematical manipulation produces a fac-
tor that is used to compare the impact/risk of the stress agents upon the biomes.
The variables were estimated for each stress agent's affect upon the biomes,
based upon the literature citations and the authors' judgements. The relative
rankings of the 14 stress agents in each of the four ecosystems are shown in Table
4 and graphically represented in Figure 1. The graphs are intended to'be relative
indices of the severity of stress agents within each biome. No pretense at scien-
tific precision is intended; rather, the graphical representation is meant to be
used as a qualitative ranking in understanding the relative importance of each
stress agent in each of the four ecosystems.
Furthermore, the impacts are evaluated for severity where they occur and not
judged for any comparative values with any other pollutants from the universe of
water pollution problems. For example, acid mine drainage impacts stand alone
for miles of streams impacted and no attempt was made to compare its severity with
that of pollution from urban runoff, solid wastes or any other covered by other
work group members.
Figure 3: Summary of impacts of stress agents upon ecosystems.
The fourteen categories on the abscissa correspond to the stress agents in
table four and are listed here for reference:
1 Acid Mine Drainage Solids
7 Mine Spoil
2 Toxic Inorganics 8 Beneficiation & Refining Wastes
9 Use-Byproducts
3 Nutrients
4 Turbidity Habitat Alteration
10 Canals
Oils 11 Causeways
5 Machinery 12 Dredging/Channelization
6 Spills
Groundwater
13 Disruption
14 Contamination
-------
Table 4
Summary of (macts on Ecosystems
Stress Agents
Fre« h w a s t er
BUFFERED UNBUFFERED BUFFERED UNBUFFERED
LAKES LAKES STREWS STREAMS
Marine/Estuarine
COASTAL OPEN ESTUARINE
DCEflN
Terrestrial
CONIFEROUS/ 6RASSLANDS DESERT/ ALPINE/
DECIDUOUS SEHI-flRID TUNDRA
FOREST
Acid Nine Drainage
Tone Inorganics
(heavy Mtalsl
Nutrients
Turbidity
Oils
Machinery
Spills
Solids
Mint Spoil
Bmficiation t
Refining Hastes
Use-Byproducts
Habitat Alteration
Canals
Causeways
Dredging/
Qianneliiation
BroundNater
Disruption
Contamination
AVERAGE
RAW
4
4
30
30
6
11
13
8
8
0
16
IB
0
0
11
39
33
30
18
5
5
7
7
4
0
16
16
0
0
14
75
75
55
55
10
12
75
30
27
70
7
70
50
35
50
75
60
55
55
6
24
65
28
28
0
7
55
50
35
42
0
27
27
27
'16
21
27
.10
10
56
52
56
3
3
26
0
6
6
6
3
10
0
0
28
0
0
0
0
0
5
3
27
27
27
IS
IS
0
30
27
44
44
44
0
0
23
65
65
20
0
6
6
75
52
39
75
0
60
75
75
47
45
45
12
33
3
3
60
30
30
30
0
0
30
22
26
0
12
12
0
11
12
15
15
0
0
0
0
11
11
a
9
18
10
0
20
20
11
24
11
45
45
45
7
7
21
-------
Tabte4 Cant
Wetlands
BUFFERED UNBUFFERED FREE SALTIMTER AVERAGE
Stress Agents
rm.iu ntrw vimnmyf
To»ic Inorganics
(heavy Mtals)
Nutrients
Turbidity
Oils
Machinery
Spills
Solids
Hint Spoil
Beneficiation 1
Refining Haste*
Use-Byproducts
Habitat Alteration
Canals
Causeways
Dredging/
Channelization
GroundMater
Disruption
Gontaunation
to
48
36
44
12
14
45
IS
15
45
45
60
33
33
60
44
36
44
12
14
60
60
30
60
60
60
7
7
60
44
36
40
10
10
75
26
26
60
60
60
7
7
0
6
0
s
3
6
0
0
35
0
0
0
0
0
33
34
26
26
9
12
35
22
21
32
23
36
IB
16
39 43 40 4 27
-------
FRESHWATER ECOSYSTEMS
so -
1 2 3 4 S 6 7 B 9 10 U 12 13 14
BUFFERED UNBUFFERED BUFFERED UNBUFFERED
LPKES LflKES STREflMS STREflWS
TERRESTRIAL ECOSYSTEMS
80 -
TO -
60 -
50 -
40 -
30 -
20 -
10 -
o -
: :
.
•
:H:
1
;
', '.
V
S
S
I,
TL *
it
i f
rJ
m
m
•
; {
'
a [
^
i '
•
^
•L
i
fj
,
| •
; •
; ; •
; -
1 '
•
>
;|
H
I
1
>
|
• -j
;L
1
a
« _
1
1
I 23456 7 8 9 10 11 12 13 14
CONIFEROUS/ GROSSLONDS DESERT/ OLP1NE/
DECIDUOUS SEMI-flRlD TUNDRfi
FOREST
MARINE & ESTUARINE ECOSYSTEMS
so -
fl
R... R
1 2 3 4 5 6 7 8 9 1O 11 12 13 14
V77X
ESTUAR1NE
CDflSTfiL
OPEN
OCEflN
WETLAfsID ECOSYSTEMS
ao
10 -
k;
k!
\
1 2 3 4 5 h 7 B 9 10 11 12 13 14
VA
BUFFERED UNBUcrERED F^£E SflLTtWTER
FLOWING
-------
In reading the graphs, the reader should beware that some assumptions and
arbitrary groupings were made in developing the categories. For example, the
category of mine spoil can also be viewed as acid spoil and includes:
o
acid mine drainage ° drastically changed runoff quantity & patterns
total dissolved solids ° unrelaimed culm or refuse piles
0 turbidity ° lands disturbed for support facilities
nutrients ° unsuccessfulr eclamation efforts
All of these adversely impact terrestrial ecosystems through depressed pH of
both surface and pore water of the soil, release of metals and nutrients, and depo-
sition of suspended solids carried by the changed runoff patterns. For this
reason, mine spoil as a stress agent invades the territory of other stress
agents. However, we do not feel this should lead the reader to conclude lesser
impacts from the other categories because they still stand on their own as
relatively serious problems.
In the category of habitat alteration, canals are differentiated from
channelized streams according to the traditional definitions. Canals are water-
ways that are created where none existed previously. Channelization refers to
streams that have been dredged to accomodate barge traffic that could not other-
wise negotiate the waterway. Both impact freshwater wetlands as well as the
marine/etuarine environments by virtue of creating a free exchange and enhanced
mixing of fresh and salt waters, equally impacting the ecological regime of each.
On first blush, some categories may appear to be skewed too high or too low;
however, this is due to the definitions used in setting up both the stress agents
and the environmental categories, making for some very broad categories and wide
ranging impacts. For example, the impact of habitat alteration on buffered streams
is high, according to our scheme, because a buffered stream includes streams with
a calcium carbonate equivalency of 20 mg/1 as well as some streams that may be pro-
tected from minimal pH changes by such naturally occuring organcic compounds as
as tannic acid. This scheme gives a spectrum of streams that includes the vast pro-
proportion of all streams. As a result, canals show a great deal of impacts to
buffered, but little to unbuffered streams. This phenomenon is also partially
attributable to the fact that, to our knowledge, unbuffered streams are located in
areas where canals are not feasible.
The reader will see that this scheme results in a means for evaluating stress
agents for their varied impacts among the four biomes. For example, number one,
acid mine drainage, shows moderate to high impacts in all by marine/estuarine.
Further selection can be made by noting that buffered and unbuffered streams
are more severely impacted than buffered lakes. The table below lists the four
biomes and their high impact stress agents.
Freshwater: acid mine drainage, toxic inorganics, mine spoil, canals, and dredging/
channelization.
MajrJjWe_st_uar_i_ne_: habitat alteration (canals, causeways & dredging/channelization)
Terrestrial: acid mine drainage, mine spoil, toxic inorganics, canals, groundwater
(disruption and contamination).
Wetlands: acid mine drainage, mine spoil, beneficiation wastes, canals, causeways,
and dredging/channelization.
-------
Regulations
Table 3, below, describes 6 Federal Acts that cover all parts of the four
ecosystems of interest. The responsibilities are fragmented among at least four
agencies, with divided regulatory authorities among many of them.
Table 3: Legislation:
ECOSYSTEMS
A
C
T
Clean Water Act:
402 (NPDES)
404 PERMITS
Clean Air Act
New Source Rev.
New Source Perf.
PSD
RCRA
SMCRA
Rivers & Harbors
Dredge & Fill
Protection
Permits (Dredge &
Fill)
Sanctuaries
Fresh-
water
Lakes &
Streams
X
X
X
X
X*
Marine/
Estuarine
Open
Ocean,
Coastal,
Estuarine
X
X
X
X
X
X
Terres-
trial
Forests,
Grass-
lands
Desert,
Alpine/
tundra
X
X
X
X
X
X
Wetlands
Fresh,
Free-
flowing
Saltwater
X
X
X
X
X*
* Covering waters declared to be navigable
A
G
E
N
C
Y
EPA/ States
COE/EPA
EPA/ States
•* H
EPA
OSM (USDI)
COE/EPA
COE/EPA
NMFS (NOAA)
Extraction wastes and beneficiation by-product disposal is also a major con-
cern. In the past, unwanted soil and rock have been left haphazardly stacked at
any convenient location out of the way. The Surface Mining Control and Reclamation
Act of '77 covers coal mining only, leaving controls on other mining (except uranium)
solely to state regulations.
Liquid wastes are usually dumped into waterways or evaporation ponds. Under-
ground injection into abandoned underground workings has also been widely used, the
subject has come to EPA's attention in the past few years and will undoubtedly under-
go further scrutiny, with this method of disposal of acid mine drainage treatment
plant waste receiving attention. All resource extraction methods should be looked
at for such geochemicals and, where necessary, regulatory programs be developed.
-------
Recommendations:
While it is apparent that a great deal of work on characterizing impacts to
the ecosystems for many stress agents, sufficient information is available to
make some strides towards tightened controls.
0 In the area of coal mining, EPA can initiate close cooperation with OSM to
include water quality benefits, where appropriate, to sites being reclaimed
using Abandoned Lands Funds. SMCRA has specified that funds are to be allo-
cated initially for correcting conditions where hazards to human health and
safety are imminent. In many cases, an incremental amount could secure con-
siderably greater benefits in water quality.
0 EPA should consider cooperation with OSM on the issue of permits consolidation.
Currently, individual permits are issues for SMCRA and NPDES . Considerable
overlap exists between the two that could be eliminated through consolidation.
In addition, a separate permit system covers the wetlands aspects. While
these concerns are often covered through the NPDES and the SMCRA permit
systems, raining operators often overlook the requirements of CWA Sect. 404.
0 The control of acid mine drainage still ranks as one of the major unresolved
problems. The status is that premine analyses commonly used is not wholly
reliable and the more reliable methods is both time consuming and costly.
In addition, postmining reclamation also has a sketchy record, resulting in
many closed mines contributing acid mine drainage through toe slope seeps.
Abandoned mines that remain unreclaimed are far and away the greatest sources
of acid mine drainage. EPA should reawaken interest in these issues and
resurrect past activities that were aimed at identifying and testing analy-
tical and treatment techniques.
0 Habitat fragmentation from oil and gas exploration and drilling should be
given closer attention by EPA than it currently receives. Both funding
and personnel resources are needed along with increased coordination with
the Corps of Engineers.
0 Many mining operations drastically alter or even destroy habitats of high
value. An example is the phosphorus mines of Florida. EPA should recognize
that a substantial effort is needed to develop mitigation and reclamation
techniques.
-------
Sources and Selected References
Alexander, M.H. 1983. Oil, Fish and Wildlife, and Wetlands ( A Review) North
eastern Environmental Science. 2:1:13-24.
Ambrose, Robert B., Jr. & D. Disney. 1986. The Computerized Ecological Risk
System (CERAS) — Functional Objectives and Prototype System. US EPA OR&D
Prepared for Exposure Evaluation Division; Office of Toxic Substances.
Biddinger, G. R. & S.P. Glass. 1984. The Importance of Trophic Transfer in Bio-
accumulation of Chemical Contaminants in Aquatic Ecosystem. Springer-Verlag.
Bosch, D.F. 1982. Proceedings of the Conference on Coastal Erosion and Wetlands
Modification in Louisiana: Causes, Consequences, and Options. Us F&WS, Bio-
logical Services. FWS/DBS-83/26.
Boulding, R. 1984. The Lost Harvest: A Study of the Surface Mining Act's Failure
to Reclaim Prime Farmland in the Midwest, in: The Illinois South Project.
Buc & Assoc. 1986. Locations of Mines and Factors Affecting Exposures. FR 51 No.
128:24501.
Charles River As.soc. 1986. Federal Non-EPA Regulations Addressing Mining Waste
Practices. FR/51 No. 128:24501.
DeLaune, R.D. et al. 1978. Sedimentation Rates Determined by 137Cs Dating in a
Rapidly Accreting Salt Marsh. Nature 275: 532-533.
Frontier Technical Assoc. 1986. Groundwater Monitoring Data on Ore Mining and
Milling Solid Waste Disposal.
Gagliano, S.M. 1981. Special Report on Marsh Deterioration and Land Loss in the
Deltic Plain of Coastal Louisiana.
Merrill, T.J. & K.V. Koski. 1979. Habitat Values of Coastal Wetlands For Pacific
Coast Salmonids. in: P.E. Gleeson, et. al. Wetland Functions and Values;
the State; £f Our Understanding. Amer. Water Resources Assoc. pp 256-266.
Neill, C. & S. Leibowitz. 1983. Modified Habitat Data for the Mississippi Deltaic
Plain and Chenier Plain Regions. Louisiana State Univ., Ctr. for Wetland Re-
sources, Baton Rouge.
Overton, J.A. 1984. Is America Rushing into Wilderness? American Mining Congress
Journal. 70:20.
Pursell, P. L. 1983. Problems with Determining Trends in Land Use Changes Following
Coal Mining in Illinois, in: Proceedings, Third Annual Conference, Better Recla-
mation with Trees. Purdue Univ.
Richardson R.V. & G.F. Nielsen. 1984. Keystone Coal Manual. McGraw-Hill
Mining Publications.
-------
Reisch, D.J. 1984. Fate and Effects of Pollutants. Jnl. WPCF. 56:6:758ff
Strauch, R. E. 1980. Risk Assessment as a Subjective Process.
. 1974. A Critical Assessment of Quantitative Methodology as a Policy
Analysis Tool. The Rand Corp., P-5282.
Stream Pollution By Coal Mine Drainage In Appalachia. 1969. USDI/FWPCA.
(out of Print)
US COE. 1984. Notice of Study Findings: Land Loss and Marsh Creation in the Lousiana
Coastal Area, Lousiana. US COE/New Orleans Dist.
US Dept. Of Energy. 1986. Natural Gas Monthly. Publ. No. DOE/EIA 0130
US Dept. Of Energy. 1985. Petroleum Supply Annual for 1985. Publ. No. DOE/EIA 0340.
US EPA. 1978. Central Florida Phosphate Industry Areavd.de Impact Assessment.
Vol. VIII. Alternative Effects Assessment p I47ff PB-296590/3
US EPA. 1985. Code of Federal Regulations: 40:257.Iff.
US EPA. 1986. Regulatory Determination for Wastes from the Extraction and Bene-
fi-ciation of Ores and Minerals. FR/51 No. 128:24496 (40 CFR Part 261).
USDI/BOM. 1981. Minerals Yearbook: Centennial Edition. Vol.1: Metals and
Minerals.
USDI. 1984. The Ecology of Delta Marshes of Coastal Lousiana: A Community Profile.
USDI/FWS & US DOD/COE. FWS/OBS - 84/09
USDI. 1967. Surface Mining and Our Environment: A Special Report to the Nation.
Varnasi, U. et al. 1985. Bioavailability and Biotransformation of Aromatic Hydro-
carbons in Benthic Organisms... Environmental Science and Technology.
19:9:836-841.
Mali, M.K. 1977. Energy and Coal Resources Development. Pergamon Press.
EPA Contacts:
Mr. Richard Sumner. Region X - Anchorage, Alaska Office (907) 271-5083
Ms. Barbara Keeler. Region VI - Regional Office (FTS) 729-6654
Mr. Rob Walline. Region VIII - Regional Office (FTS) 564-1596
Mr. Schregardus. Region V - Regional Office (FTS) 886-6760
-------
Environmental Problem: Accidental Releases — Toxics (#21)
Accidental releases of toxic chemicals occur during the
transport of chemicals or at production facilities. Trans-
port involves truck transport via highways, barqe transport
on inland waterways, pipeline transport, rail transport, and
tanker transport offshore and in large inland water bodies.
Releases of toxic chemicals occur in all media and involve a
wide range of chemicals.
Available data (which is acknowledged to understate
releases) indicate that there are about 2,000 accidental
releases of CERCLA listed chemicals per year, resulting in
an average of about 40 million pounds of releases per year.
(The number of releases is relatively similar from year to
year, but the guantity of releases varies considerably.)
About 12 percent of releases are to water. Of this, about
3.5 percent are to sewers (and may have subseguent effects
if POTWs cannot adeguately treat the released material),
about 1.5 percent are to the oceans, and about 8 percent are
to inland waterways.
Most accidental releases involve relatively small guan-
tities of material. But it is the infreguent, large guantity,
releases that dominate in terms of total material released
-- only 2.4 percent of the number of releases account for
over 90 percent of the guantity of material released. The
types of chemicals released in greatest guantities and high-
est freguencies are acids, bases, and non-persistent organics
(PCB releases are mostly to land).
Accidental releases of toxic substances are unlikely to
substantially affect terrestrial ecosystems, but they may
create significant localized effects of short duration to
freshwater ecosystems. Releases to marine, estuarine, and
wetland ecosystems are infreguent, but could result in signi-
ficant localized effects. There always exists the potential
that low probability events involving releases of large
volumes of highly toxic and persistent compounds coud result
in significant and persistent local and regional effects to
marine environments.
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Environmental Problem: 21, Accidental Releases — Toxics
I. Description of Sources
Accidental releases of toxic chemicals occur during the transport of
chemicals or at production facilities. Transport involves truck transport
via highways, barge transport on inland waterways, pipeline transport, rail
transport, and tanker transport offshore and in large inland water bodies.
Releases of toxic chemicals occur in all media and involve a wide range of
chemicals. Depending on the specific case, the effects of an accidental
release can vary from being minor, to causing significant short term, but no
long term, effects, to causing persistant and substantial damage. Substantial
ecological effects are more likely for spills into water because of the
potential for the spread of the chemicals and the difficulty of containinq
and removing or treating the released materials.
Accidental releases are infreguent, probabilistic events, which makes it
difficult to forsee whether accidents in the future will have severe environ-
mental conseguences, such as the recent disaster at Basel, Switzerland. The
approach followed here is to summarize reported information on the frequency,
general locations, and volume of releases and on the types of chemicals most
frequently released to develop a general indication of the likely severity of
ecological effects from releases of toxic chemicals.
II. Detailed -Description of Sources, Releases, and Exposures
The data1 in the table below indicate that there are about 2,000
accidental releases of CERCLA listed chemicals per year, resulting in an
average of about 40 million pounds of releases per year (the number of releases
is relatively similar from year to year, but the quantity of releases varies
considerably).
NRC Notifications of Releases of
CERCIA Chemicals
Year Number Qjantity
(million Ibs)
1982 1,664 10.7
1983 2,014 93.6
1984 1,991 11.1
1985E 2,523
Avg. 2,048 38.5
The data relied on are acknowledged to undereport the number of releases,
possibly by a factor of 2 or more, and the volume of releases. Most
releases are reported to some governmental authority, either at the local,
state, regional, or national level. Cleanup responses then usually are
initiated if needed. However, if releases are reported to agencies other
than the National Response Center (NPC), it is likely that the releases
are not included in the NRC data base referenced by this paper.
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-2-
Most of these releases are from fixed facilities and are restricted
to land, as shown below. Of the 12 percent of releases to water, about 3.5
percent are to sewers (and may have subsequent effects if POTWs cannot
adequately treat the released material), about 1.5 percent are to the
oceans, and about 8 percent are to inland waterways.
Percent Distribution Percent Distribution
of Number of Releases of Number of Releases
Mode 1982-85 by Mode Medium 1982-85 by Mode
Higway 7.9% Air 16.0%
Marine 1.2 Land 53.7
Pipeline 1.6 Water 12.0
Rail 13.3 Unknown 18.3
Offshore 0.2
Fixed Facility 75.9
and other
Accidental releases of toxic chemicals are probabilistic events.
Accidental releases typically involve relatively small quantities of
material, but it is the infrequent, larqe quantity releases that dominate
in terms of total material released* This is shown in the table below,
where only 2.4 percent of the number of releases account for over 90
percent of the quantity of material released.
Distribution of Number and Volume of
Pounds Releases, by Size of Release, 1982-84
Released Number Quantity
<10 9.9%
10-100 42.3 0.1%
100-1,000 19.6 0.3
1,000-10,000 16.0 2.4
10,000-100,000 9.7 12.8
100,000-1,000,000 2.1 22.5
>1,000,000 0.3 67.8
The types of toxic chemicals rleased in larqest quantities qenerally are
common production chemicals. In 1983, however, there were a number of larqe
volume spills that tend to skew the numbers (this is inherent in probabilistic
type releases). Provided below is information on the percentage volume releases
for chemicals released in greatest quantities and the frequency of releases for
the most frequently released chemicals.
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Chemical
Sulfuric Acid
Hydrochloric Acid
Sodium Hydroxide a
Caustic Soda Solutin a
Methyl Alchohol
Nitric Acid
Phosphoric Acid
Benzene
Ferric Chloride
PCBs
Toluene
Potassium Cyanide
Sodium Cyanide
Radioactive Material
Anhydrous Ammonia
Chlorine
Methyl Chloride
Vinyl Chloride
TOTAL
-3-
Percent Distribution of Volume of
Releases and of Frequency of Release
Volume of
1982 & 1984
20.6%
10.3
9.0
5.1
4.2
3.6
3.2
3.2
3.1
2.7
2.4
Top Ten
1982 to 1984
30.1%
3.0
3.7
3.3
1.1
17.7
16.7
3.9
2.3
1.7b
Frequency of
Ten, 1982 to
8.1%
4.0
2.3
2.1
1.5
35.6
6.0
6.2
2.6
1.6
Top
1985
64.4%
81.2%
70.0%
a Substances chemically identical; caustic soda is in solution.
b Mostly uranium mill tailings.
PCBs are reported spilled with the greatest freequency. About 90 percent
of these involve power companies and occur primarily as a result of equipment
failure and of maintenance activities. Most PCB releases, thus, would be
confined to land. They are expected to decline as the PCB phase out continues.
Releases of anhydrous ammonia, chlorine, methyl chloride and vinyl chloride
are reported frequently but do not account for a large volume of releases.
This is because the reportable guantities for these chemicals are set
very low— 100, 10, 1 and 1 pounds, respectively.2
Response actions are taken to address most spills, but the extent to
which releases of toxics are contained, removed from the environment, or
neutralized is unclear. Releases to the air cannot be addressed except
through removal of the source. However, such releases would likely have
only short term effects (if any) on ecological systems. Releases to land
generally can be contained and effectively remedied. Given that most releases
are from fixed facilities, important and sensitive land-based ecosystems
probably are not very often affected. Releases to marine environments are
the most problematic. The ability to remedy the spill will depend on a host
of factors specific to the incident. The conseguent effects of the residual
release on the aquatic environment will depend on the characteristics of the
2/ If a release exceeds the "reoortable guantity," the responsible party
is required to notify the NRC and report the release.
-------
chemical (persistance, bioaccumulative properties, and toxicity). We do not
have information to characterize the short and long term effects of releases
already experienced. However, given the types of chemicals released in
greatest quantities and highest frequencies — mostly acids, bases, and
non-persistant organics (PCB releases are mostly to land) — it would anpear
that most ecological impacts would be localized and of short duration. This
observation, of course, does not rule out the potential for a natural disaster
at a regional level from an accidental releases of large volumes of highly
toxic and persistant chemicals.
III. Evaluation of the Problem
The available information suggests that:
1) terrestrial ecosystems are unlikely to be substantially affected;
2) freshwater ecosystems are likely to have significant localized
effects from releases, but they are likely to be of short duration;
3) marine and estuarine systems are infrequently affected by releases;
4) wetland ecosystems could have significant localized effects
(probably of short duration) but releases to such systems occur
infrequently; and
5) there always exists the potential for highly significant and
persistant local and regional effects to marine environments from
low probability events involving releases of large volumes of
highly toxic and persistent compounds.
Sources of information:
U.S. Department of Transportation, Transportation System Center, Addendum,
Patterns and Trends for National Response Center Hazardous Releases,
July 1985.
U.S. Department of Transportation, Transportation System Center, Patterns
and Trends, National Response Center Data, 1982-1985 Update, with Quantities,
Injuries, and Fatalities, Mar-eh 1986.
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Environmental Problem: Accidental Releases — Oil (#22)
Accidental releases of oil occur during the transport of
oil in vessels, tank trucks, and pipelines; from marine- and
land-based transfer facilities; and from refinery, bulk
storage, and on- and offshore production facilities. Releases
of oil range from crude petroleum to gasoline and other
distillates. We focused only on releases to water, as it is
likely that ecological effects would be of larger scale and
more severe for aquatic rather than for terrestrial ecosystems.
On average, there are over 9,000 oil spills per year
resulting in releases of about 11 million gallons of oil.
Most reported spills are fairly small — over 90 percent of
spills for which the release volumes are reported are less
than 1,000 gallons. On the other hand, the relatively small
number of spills greater than 10,000 gallons, about 1.3 per-
cent of reported spills, account for over 80 percent of the
volume of- spills.
Although oil spills to water are freguent eve-nts, gener-
al-ly the amounts spilled or left unrecovered after cleanup
activities are small enough so that natural systems are not
significantly threatened. The very infrequent large size
spill in confined waters can cause significant short term
localized damage. However, even in such cases the combination
of cleansing processes of natural systems, weathering of
oil, and cleanup efforts have resulted in ecosystems recover-
ing relatively quickly.
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Environmental Problem: 22, Accidental Releases — Oil
I. Description of Sources
Accidental releases of oil occur during the transport of oil in vessels,
tanker trucks, and pipelines; from marine- and land-based transfer facilities;
and from refinery, bulk storage, and on-and offshore production facilities.
Releases of oil range from crude petrolium to gasoline and other distillates.
Releases can occur to all media, but the focus here is on releases to water,
as data are available to characterize releases to that medium and it is
likely that ecological effects would be of larger scale and more severe for
aguatic rather than terrestrial ecosystems.
II• Detailed Description of Sources, Releases, and Exposures
The data in the table below indicate that, on average, there are over
9,000 spills per year resulting in releases of about 11 million gallons of
^i 1 1
oil.
Number
10,990
9,194
8,820
8,612
9,208
Quantity
(000 gal.)
10,500
10,171
17,800
9,188
8,270
Number and Quantity of Oil Spills
1879 - 1983
Year
1979
1980
1981
1982
1983
Avg. 9,365 11,186
Most reported spills are fairly small — over 90 percent of spills for
which the releases volumes are reported are less than 1,000 gallons. On the
other hand, the relatively small number of spills greater than 10,000 gallons,
about 1.3 percent of reported spills, account for over 80 percent of the
volume of spills. This is shown in the table below. The data indicate that
it is the infrequent, large release event that dominates releases to the
environment.
Some small spills may not be reported. Many spills reported are from
unknown sources, are of unknown quantity, or are sheens that have been
observed.
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-2-
Distribution of the Number and
Quantity of Spills, by Spill Size
1982 and 1983g.
Spill Size Number Quantity
<10 39.5% 0.1%
10-99 36.5 0.9
100-999 16.8 3.6
1,000-10,000 5.8 13.3
10,000-100,000 1.1 21.3
100,000-1,000,000 0.2 35.9
>1,000,000 <0.1 25.0
a About 28 percnt of reported spills either are of unknown quantity or
are sheens. Such spills are not included in the above calculations.
The distribution of oil releases by type of product is shown in the
table below. Crude oil accounts for over 40 percent of releases and
diesel and fuel oil together account for about 30 percent. Average spill
sizes are similar for most products — about 1,000 gallons.
Distribution of Oil Spills by
Type of Product, 1982 and 1983
Product Number Quantity
Crude Oil 24.2% 41.6%
Gasoline 6.0 7.5
Other distillate 2.4 3.6
Solvents 0.6 0.4
Diesel oil 22.6 17.2
Fuel oil 5.2 11.3
Asphalt Aar/Pi tch 1.0 0.7
Animal/Veg. Oil 0.3 1.1
Waste Oil 8.0 6.6
Other oil 29.4 9.9
Over 70 percent of the quantity of oil spills occurs in inland areas as
opposed to coastal areas as shown below. The average spill size in inland
areas is about double that for coastal areas.
Distribution of Oil Spills by
General Areas, 1982 and 1983
General Area Number Quantity
Inland 41.3% 73.1%
Atlantic 20.3 4.8
Pacific 12.7 8.2
Gulf 24.4 12.6
Great Lakes 0.4 0.1
Other 0.7 1.2
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-3-
Within inland areas, most spills affect rivers, beaches, and non-
navigable waterbodies, as shown below.
Distribution of Spills in Inland
Areas, by Location, 1982 and 1983
Location Number Quant ity
Qpen internal waters 14.1% 10.8%
River chanels 46.3 45.1
Ports & harbors 10.5 2.9
Beaches & non-navig. 29.0 41.2
Spills in coastal areas are mainly in ports and harbors and in the
rivers connecting terminal facilities to harbors. The distribution of
spills by location for the combined coastal areas is shown below.
Distribution of Spills for the
Atlantic, Pacific, and Gulf Areas
by Location, 1982 and 1983
Location Number Quantity
River channels 25.0% 37.7%
Ports & harbors 30.4 35.0
Beaches & non-navig. 3.4 4.2
Shore - 3 MI 14.1 16.2
3-12-MI 9.8 4.0
High Seas 17.2 3.0
Most of the spills in river channels are on the east coast and most of
the spills in the 3-12Mi and high seas locations are in the Gulf coast area.
In summary, the information on releases indicates that: (1) there are
a substantial number of spills each year, but the bulk of these are under
1,000 gallons; (2) a relatively small number of large spills dominates the
volume of releases; (3) most releases are of crude oil and diesel and fuel
oils, (4) most releases are in inland areas; and (5) rivers, beaches, and
non-navigable waterways mostly are affected by spills in inland areas.
Assessing the likely environmental conseguences of future oils spills
is problematic because they are probalistic events. The impact in an
ecosystem would depend on many factors, such as the size of spill, the
product, location of the spill, and the ability to contain, collect or
disperse the spill. Spills would have the most severe impacts if: 2
0 The spill is in a confined, shallow water body and the volume of the
spill is large relative to the body of water;
2/ See McAuliffe, "Fate and Effects of an Oil Spill from Canadian West
Coast Offshore Exploration," in Offshore Hydrocarbon Exploration, West
Coast Offshore Exploration Environmental Assessment Panel, April 1986.
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-4-
0 the oil is a light, refined oil, such as home heating or diesel oil;
and
0 there is a high load of fine sediment in the water column.
Spills of this type are rare, but can significantly reduce populations
of benthic (bottom feeding) communities for years. However, even for these
kinds of spills (Torrey Canyon, Metula, and Amoco Cadiz) the shoreline plants
and animals have recovered over time. Spills of oil in lesser amounts, and
in unconfined waters have less severe short term impacts. Weathering of oil
and cleansing properties of natural systems in such circumstance generally
result in fast recoveries of those systems.
A series of case studies of spills is presented in the 1985 Oil Spill
Conference Report. They involve a near shore spill, a spill on arctic tundra,
a spill to an estuary, and spills to a freshwater river, wetland, and creek.
Short term damage was limited because of the nature of the systems and cleanup
responses. All systems recovered from the spills within a year or two.
III. Evaluation of the Problem
The information indicates .that oil spills to water are frecruent events.
But, generally, they are in amounts small enough, in combination with cleanup
activities, to not significantly threaten natural systems. The very infre-
quent event of a large size spill in confined waters can cause significant
short term localized damage. However, even in such cases the combination of
natural cleansing processes and cleanup efforts have resulted in ecosystems
recovering relatively guickly.
Sources of Information:
U.S. Department of Transportation, Polluting Incidents In and Around U.S.
Waters, Calendar Year 1987 and 1983.
American Petroleum Institute, Proceedings, 1985 Oil Spill Conference.
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FINAL DRAFT
11-21-86
RELEASES FROM UNDERGROUND STORAGE TANKS:
A PRELIMINARY ANALYSIS OF ECOLOGICAL RISKS
I OVERVIEW
This paper analyses the ecological risks associated with the storage
of petroleum and chemical products. The scope is restricted, however, to
underground storage tanks (UST), even though petroleum and chemical
products occur in other places across the country, including surface
tanks, pipelines, and transportation units (trucks, shipping rail), all
of which contribute to potential ecological risks. The papers focuses on
USTs because of the large number of reported releases from this source
and the lack of Agency attention to potential ecological risk.
This paper will describe sources, releases, types of products and
constituents, proposed regulations, and state-of-knowledge about ecosystem
esposure and impacts. The paper concludes that UST leaks can result in
significant local ecological risk if an ecosystem is exposed, but that
low risks are usually associated with leaking USTs because tanks are
typically located in disturbed settings and leak product does not reach
natural ecosystems. Consequently, despite a large number of leaking tanks,
from a national perspective, ecological risks are ranked as low.
II DESCRIPTION OF SOURCES, RELEASES, CONTROLS AND EXPOSURES
Sources. The proposed UST regulation will apply to an estimated 1.4
million tanks — over 95% (1,350,000) store petroleum products (half for
retail sales and half for industrial usage) and about 4% (54,000)
contain hazardous chemicals. An estimated 3 to 7 million tanks are
currently exempted from regulation. This paper will focus on tanks that
are to be regulated because of information availability.
Releases. The EPA Office of Underground Storage Tanks estimates that
the number of USTs that are currently leaking is between 10-25%. This
translates into 140,000-350,000 leaking tanks. Although industry-sponsored
studies suggest that there are very few leaking USTs, studies and anecdotal
reports from Federal, State and local governments indicate that a large
number of tanks are leaking. New York's Suffolk County instituted tank
testing requirements in 1980, and it appears that 20% of their 8,000 tanks
were leaking. Officials in Dade County, Florida, reported the presence
of petroleum in ground water at 10% of the tank sites where monitoring
wells were installed. In May, 1986, a report by OPTS1 estimated that 35%
of nonfarm USTs storing motor fuel were leaking under test conditions based
on a tank tightness tests of national sample.
Several EPA studies have addressed the nature and national scope of
the UST problem. The OPTS study estimated the average leak rate, under
test conditions, to be 0.3 gallons per hour, which could result in up to 2500
1 Underground Motor Fuel Storage Tanks; A National Survey. EPA 560/5-86-013.
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—2—
gallons per year. Another Agency study2 completed in July, 1986 compiled
information on 12,000 actual UST release incidents between 1970-1984
(three quarters of which occured after 1980). These results indicate
that 33% of the incidents involved releases of 100 gallons or less, about
50% were between 100 and 2500 gallons, and 12% were between 2500 and 10,000
gallons. Less than 5% were greater than 10,000 gallons.
Stress Agents. A wide range of commercial petroleum products are
produced from crude oil, including highly refined gasolines, fuel oils,
lubricants, solvents, liquified petroleum gases, building materials and
petroleum coke. Petroleum products that are stored in USTs in large
quantities are motor fuels (aviation gasoline, motor gasoline, diesel
fuel and jet fuel), heating oils (distillate fuel oil and residual fuel
oil), solvents, and automotive and industrial lubricants.
Petroleum is comprised of hundreds of compounds, primarily simple
saturated and unsaturated hydrocarbons. A wide variety of compounds are
added to enhance performance of the product or iitpart certain charac-
teristics. These additives are often very toxic, and some cases
carcinogenic. In terms of human health effects, benzene, toluene and
xylene are commonly used as surrogate stress agents because of their
human toxicity and mobility in the environment. Analogous surrogate
indicator compounds for ecological effects have not been identified.
About 480 of the 715 CERCLA hazardous substances may be stored in
USTs, but little information is available on what substances are actually
being stored and in what quantities. Preliminary information indicates
that six (low molecular weight organic) solvents — acetone, methanol,
toluene, xylene, methylene chloride and methyl ethyl ketone — account for
over 50% of UST chemical tanks and total volume. Pesticide formulations
and inorganic compounds are also stored in USTs, but insufficient
information exists to characterize this segment.
In terms of the "stress agents" identified by the Ecosystem Research
Center, "oil and petroleum products" are the primary agents from leaking
USTs. Petroleum UST leaks also contribute air emissions (i.e., "gaseous
phytotoxicants"). Stress agents from chemical-tank leaks could include
"gaseous phytotoxicants" to air; "toxic organics and toxic inorganics" to
water (as well as possibly others, such as "pesticides" and "acids"); and,
"toxic organics and inorganics" to terrestrial ecosystems.
Regulatory Control. Subtitle I of the Hazardous and Solid Waste
Amendments (HSWA) of 1984 established a comprehensive regulatory program
for "underground storage tanks." The statute defines an UST as any tank
(or combination of tanks) with at least 10% of its volume below the
ground, including piping, that holds a "regulated substance-1."
2 A regulated substances is defined as petroleum or substances defined as
hazardous under CERCLA, but excludes subtances regulated as a hazardous
waste under RCRA. The Agency currently regulates about 10,000 hazardous
waste tanks under RCRA.
3 EPA. Sumnary of State Reports on Releases from Underground Storage Tanks.
EPA/600/M-86/020. July, 1986.
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-3-
HSWA excludes from regulation a nurrber of USTs (e.g., smaller farm and
residential tanks storing motor fuel for non-commercial use; building
heating oil tanks; septic tanks; pipeline facilities; flow-through process
tanks; tanks directly related to oil and gas production; surface impround-
ments), and EPA is currently studying these excluded tanks to determine
if the regulated universe should be expanded. EPA is considering an UST
regulation with the following elements:
New Tanks: o Corrosion-protected single-walled tanks with
frequent-to-continuous leak detection
Existing Tanks: o Mandatory retirement or upgrade to new tank
standards within in years
o Periodic tank testing (or other leak detection
system) in interim (bare steel every three
years; corrosion-protected tanks every five
years)
Chemical Tanks: o Secondary containment for new tanks with variance
based on leak detectability of substance stored
o Mandatory retirement and leak detection for
existing tanks on same schedule as petroleum
tanks
Corrective
Action: o Site-by-site assessment approach
These new regulatory controls are expected to significantly reduce
the UST environmental problems. Secondary containment for new chemical
tanks may reduce the likelihood of releases to nearly zero. The corrosion
protection requirements and leak detection requirements for petroleum
tanks will significantly reduce the nunber of releases, as well as the
size of releases that do occur. Overall, the effect of new Federal
regulations, in concert with emerging state program capabilities, is
predicted4 to reduce the UST problem (i.e., using a surrogate measure —
"plume -acres avoided") by more that 90%. The leaks that do occur will
be assessed on a site-specific basis to determine appropriate cleanup
requirements.
For this analysis of ecological risks, it is reasonable to assume
that the baseline conditions take into account a 90% problem reduction
gained by anticipated future UST regulation.
Exposure. The geographical distribution of tanks correlates, at a
national scale, with human population density. Therefore, most tanks are
located in urban areas where the natural ecosystems have already been
4 Unpublished analysis by the EPA office of Underground Storage Tanks.
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-4-
significantly altered. Thus, UST leaks that result in exposure to
natural ecosystems are rare relative to the total number of leaks.
However, given the number of tanks and the high leak rate (up to 25%),
the cumulative ecosystem exposure nationwide could be significant.
A leaking UST can be considered to be a point-source discharge
having two different transport pathways — liquid and vapor. Discharges
are usually to the soil (but can be directly to groundwater where a tank
is located in groundwater) and contaminants can be transported to ground
water, surface water and the air.
In terms of the liquid phase, movement of the product is a function
of the quantity and physical properties (solubility, specific gravity,
viscosity, evaporation rate, etc.) of the contaminants and the environmental
conditions of the site (location of the ground water table, structure of
the subsurface soil and rock, proximity to surface water, etc.). Transport
of the contaminant in the unsaturated zone is characterized by vertical
flow driven by gravity and lateral speading. Because of viscosity
differences, heavy oils do not readily penetrate the soil, whereas lighter
products like gasoline move through the soil more quickly than water. In
general, the contaminant plume will take on a pear-shaped form as it
moves through the unsaturated zone, but the shape can be irregular. If
the plume reaches groundwater, dissolvable substances (e.g.,r benzene)
will enter the groundwater and be transported in the direction of the
groundwater flow. Enmiscible (nondissolvable) substances that are "lighter"
than water will build up as a floating plume on the ground water surface,
and denser immiscible substances will sink.
Much less is known about vapor-phase transport. A liquid contaminant
leaking from an UST will enter the vapor state (evaporate) according to
its vapor pressure, and will move predominately downward and horizontally.
Impacts. Few ecological impacts from leaking underground storage
tanks have been reported, but this may be due, in part, to tine lack of
proper examination. The OUST release incident survey^ showed that in most
cases health or environmental impact were not documented. Of those sites
that did report an impact, about 10% identified damage to the immediate
ecosystem in the form of damage to aquatic life, wildlife, plant life, or
crop loss, as follows:
Reported impacts No. Cases
Damage to aquatic life, wildlife, plants, crops
Contamination of drinking water supplies *
Contamination of other surface and ground waters
Human illness and death
Fire and explosion, and threat of fire and explosion
Other
Total
*Including private and public wells and potable surface waters
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-5-
UST releases, which include surface spills and subsurface leaks, are
reported to affect these media: soil (77%), ground water (53%), surface
water (22%), and air (16%) — note that several media can be affected by
a single release.
In many cases, the immediate zone around the storage tank assimilates
the release without offsite damage to the environment or human well being.
Although many factors affect the transport and fate of petroleum and
hazardous substances, most releases are confined to the soil in the
immediate area, which invaraibly has been altered previously by other
human activities. Furthermore, most releases to ground water are also
confined to a relatively small area (in some cases, however, contaminated
ground water, or release material itself, has entered terrestrial and
aquatic ecosystems. Significant ecological impacts are rare, and are a
largely a function of the volume and site-specific location of a release.
Although, impacts on ecosystems have been little noted, the long-term
imparts and the high frequency of low-level releases could have serious
impacts.
Although the leaking UST problem has emerged recently as an environmental
problem, a considerable body of knowledge exists about the impact of oil
pollution on marine and estuarine ecosystems. Severe localized damages -
such as immediate decimation of fishes, shellfish, worms, and seabirds at
the site of a spill have been well studied. Whereas immediate death to
marine birds often occurs as a result of damage to feathers and death to
fishes as a result of clogged gills, the toxic compounds in petroleum can
also result in more complex impacts, including nonlethal effects and
transport of toxicants through food chains. Long-term effects, such as
loss of reproductive capability in surviving mussels and alternative of
the feeding behavior of lobsters, have been shown to last for up to 10
years after an event. In addition, detergents used in clean-up operations
have also been shown to have toxic effects.
In water, most petroleum compounds evaporate, oxidize or degrade as
a result of bacterial action. Some dissolve, some settle or accumulate
tar balls, some become surface films and some enter organisms.
Biodegradation of Petroleum. Petroleum is a naturally occuring
substance, and as might be expected, many of its constituents can be
degraded by biological activity. In terrestrial ecosystems, degradation
in most prevalent in the unsaturated zone where conditions are most
favorable for micrcbial activity. Degradation is microoganism-specific
and dependent on available oxygen and other environmental factors at a
site.
The hydrocarbon fraction of petroleum products is most amenable to
bacterial action in favorable conditions, but the fate of petroleum
additives is less certain. Petroleum additives (e.g., anti-foam, anti-
knock, anti-corrosion, deicers, detergents, octane improvers, friction
rodifiers) are quite numerous, particularly for motor fuels, and can be
present at concentrations ranging from a few parts per million to as much
as 10% by volume. Many petroleum additives are hazardous substances and
-------
therfore their presence is important when addressing the evironmental
significance of UST leaks. Identifiable petroleum additives that are
also on the list of hazardous substances stored in UST's include
tetraethyl lead, ethylene dibromide, ethylene dichloride, dimethyl amine,
and methanol.
Ill PROBLEM EVALUATION
Based on the information presented in this paper, Figure 1 contains
a proposed ranking of ecological effects from leaking USTs. The overall
ecosystem effects of leaking USTs is rated low for two reasons: most USTs
are located in or near severly disturbed or previously destroyed natural
areas; and, although leaks from both petroleum and chemical USTs can
result in significant local ecological effects if an ecosystem is exposed,
most releases (spills and tank system leaks) do not move very far from
the point of discharge and do not result in significant ecosystem exposure.
Exceptions do occur but are restricted to USTs in areas with a high
groundwater table or where surface waters are adjacent to releases. The
only documented ecological impacts are very local effects on adjacent
terrestrial systems and on aquatic systems (e.g., fish kills in streams).
The air-transport route for VOC's and the contribution to air quality
degradation have not been well characterized.
The regulatory controls that will be implemented over the next
decade, together with emerging problem awareness in state and local
governments, will significantly reduce the future potential for ecological
disturbance. The present regulatory focus addresses the potential impacts
on drinking water supplies, and the immediate threats of fire and explosion
from leaking USTs. Potential ecological risks will probably largely
be avoided as a indirect benefit of addressing the human health impacts.
-------
Figure 1. Proposed Ranking of Ecological Risks from Leaking
Underground Storage Tanks.
Ecosystems
Freshwater
Marine and estuarine
Terrestrial
Wetland
Buffered lakes
Unbuffered lakes
Buffered streams
Unbuffered streams
Coastal
Open ocean
Estuaries
Coniferous forest
Deciduous forest
Grassland
Desert/Semi-arid
Alpine/Tundra
Freshwater - isolated
Freshwater - flowing
Saltwater
0)
*
(0
o
-r-l
51
•3
m
4-3
.
in
H
H
H
H
H
L
H
_
-
—
-
H
M
M
M
M
M
M
M
M
L
M
H
M
M
M
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
?
L
L
L
L
L
.L
L
L
L
5 The significance of ecological effects of an UST release that occurs in
or reaches a particular ecosystem type.
6 The time required for ecosystem recovery after an UST release (L = 1 year;
M = 10 years; H « 100 or more years)
At a national scale, the expected exposure of different ecosystems to
UST releases.
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Other Sources of Ground-Water Contamination
Over 200 contaminants have been identified in ground water.
This contamination results from a wide variety of point and non
point sources that encompasses every day activities ranging from
waste disposal practices to road de-icing. Should ground water
contaminated by these sources discharge into an aquatic or wetland
ecosystem, there is the potential for organisms and chemical
processes to be affected. This paper discusses the ecological
risks posed by contaminated ground water.
For the purposes of this paper ten sources of contamination
have been grouped and identified as "other sources of ground-water
contamination". These categories are : septic tanks and cesspools,
class V injection wells, waste water spray irrigation, material
stockpiles, pipe lines, irrigation practices, non point discharges
to ground water, production wells, salt water intrusion, and oil
production holding ponds. Stress agents released from these "
other sources of contamination include: toxic organics, pesticides,
toxic inorganics, nutrients, microbes, acids, oil and petroleum
products. Specific contamination incidents,such as selenium
contamination from irrigation return flows at Kestersori Reservoir
have resulted in fish and water fowl deaths, genetic abnormalities
and reproductive problems verify the potential for severe local
effects.
These ten sources number in the millions and are distributed
throughout the United States. Therefore the potential for ground-
water contamination and subsequent ecological risk could be enor-
mous. This ecological risk is somewhat tempered because the
ecological impacts groundwater contamination are quite site and
time specific. Additionally, an impact can only occur if contam-
inated ground-water discharges into an ecosystem and if there is
a sufficient volume and concentration to impact the biological or
chemical components of the system. In general,only aquatic and
wetland ecosystems will be directly impacted from contaminated
ground water. Filtering properties of soil and the dilution and
dispersion properties of streams, lakes, and bays can also reduce
the ecological risk posed by contaminated ground water. Unfortun-
ately data does not exist to verify total number of incidents on
a regional, national, or global level making it impossible to
determine the actual versus potential risk is from these sources.
This environmental problem has been given an overall ecolog-
ical risk rating of medium. Even though the ecological impacts
from these sources are mainly at an ecosystem level the number of
such sources are large and therefore the potential risk is high.
A more complete data base detailing the level and location of
ground-water impacts is needed to verify the magnitude and extent
of the ecological risks from other sources.
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INTRODUCTION
Over 200 contaminants have been identified in ground water.
(Stone et al., 1984) These include a variety of metals, toxic
organics, toxic inorganics, pesticides, herbicides, radionuclides,
and microbes. Incidents of contamination have been documented in
every state, often occurring near industrialized, heavily populated
areas. Should contaminanted ground water be discharged into an
ecosystem, severe local impacts could occur.
Ground-water con 1-am in ants are released from a wide diversity
of point and non point sources. A 1984 OTA report "Protecting
Our Nation's Ground Water From Contamination" (Stone et al. 1984)
identified 33 major categories of ground-water contamination sources
For the purpose of the comparative risk study, ten categories of
ground-water contamination sources have been grouped together and
are identified as "other sources of ground-water contamination".
These are:
Se-ptic Tanks and Cesspools
Class V Injection Wells
Land application of nonhazardous waste and nonsludge material
(waste water-spray irrigation)
Material stockpiles (non waste)
Pipelines (hazardous and non hazardous waste)
Irrigation practices (irrigation return flows)
Nonpoint discharges to ground water(fertilizer application,
animal feeding operations, deicing salt applicaions,
urban runoff, etc.)
Production wells (oil and gas, geothermal and heat recovery
wells water supply wells, etc.)
Salt Water intrusion
Oil production holding ponds
-------
This list focuses on those sources which because of their
number, general locations, or the type of contaminants released
are likely to pose an ecological risk. These "other
sources of ground-water contamination" number in the millions and
are distributed though out the United States. Additionally, sources
are everyday practices such as road salting, fertilizer application
etc. Therefore, the potential for ground-water contamination and
subsequent ecological impact is enormous. It should be emphasized
however, that ecological impacts caused by ground water are very
site and time specific. Extent of impact is greatly influenced
by such factors as: contaminant concentration, volume of dicrVrge,
ar.d ]>to\iuiity o£ Uie source to the point of discharge.
The only time there will be an ecological impact from an
"other source of ground-water contamination" is when the contami-
nated ground water surfaces from an aguifer via a discharge
point. Thus even though ground water at a particular site may be
contaminated enough to pose human health risks if consumed, it
will not pose an ecological risk until it exits the aguifer in-to.
an -ecosystem, and plant and animal communities are exposed- to the
contaminants. The contaminated ground water can be considered
the stress agent which can cause several types of ecological
impacts including: changes in biotic community structure, changes
to ecological processes, and the elimination of species particularly
important to humans. Since aquatic and wetland ecosystems are
usually discharge areas, they are the ecosystems the most suscep-
table to impacts from contaminated ground-water.
Several examples of documented ecological impacts from "other sources
of ground-water contamination" are listed below: Nitrates from
both septic tanks and agrichemicals can cause eutrophication and
algal blooms in lakes. Brines discharged from oil operations
have resulted in numerous fish kills in Pa, W.V., N.Y. and several
midwestern states. An additional effect associated with brine
contamination is landscaring which results in the stunting and
death of trees and grasses along stream banks where ground water
is discharged. Finally selenium leached out of the soil by irriga-
tion return flows have resulted in waterfowl kills aad genectic
abnormalities.
No compilation of ecological impacts from ground
water contamination or an analysis of the national scope of such
incidents exists at this time. This problem may never be docu-
mented due to the prohibitive costs associated with collecting
such data.
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SOURCES, STRESS AGENTS AND EXPOSURES
SEPTIC SYSTEMS
Stress Agents - nutrients, toxic inorganics, microbes, toxic
organics.
Potential for Exposure - It has been estimated that there
are 22 million domestic domestic septage systems in the United
States. A 1983 report indicates that these systems release
between 820 and 1460 billion gallons of waste annually.lt is is
c... Iliad teJ iliaL 2'_>,GGC inclustriaJ scpLage systems discharge between
1.2-1.9 billion gallons of waste annually ( OTA 1984 ).
Geographic Variability - The highest regional densities of use
are in the eastern third of the country and along portions of the
west coast (OTA 1984 )
Ecosystem Exposures - streams, lakes, estuaries and wetlands,
freouency and duration unknown.
Controls - local ordinances and state laws: regulation is variable.
Information Completeness - poor
CLASS V INJECTION WELLS (only Class V wells are discussed because
of regulatory programs in place to prevent contamination from
Class I, II, III and IV wells.
Types - Drainage Wells (a.k.a. Dry Wells), Geothermal Reinjection
Wells, Domestic Waste Water Disposal Wells, Mineral and Fossil
Fuel Recovery Wells, Oil Field Production Waste Disposal Wells,
Industrial/Commerical Disposal Wells, Recharge Wells, and
miscellaneous wells.
Stress Agents - pesticides, herbicides, nutrients, microbes,
acids, oil and petroleum products, thermal pollution, toxic
organics and toxic inorganics.
Potential for Exposure - There were approximately 116,150 class
V wells in operation as of March 1986 ( EPA 1986). The ones with
most potential numerically and volumetrically to contaminate
ground water are drainage wells. The most common of these wells
are: agricultural drainage wells (950), storm water and industrial
drainage wells (54,000 combined) (EPA 1986).
Geographic Variability - Agricultural drainage wells are most
common in IA, ID, TX and CA. Industrial drainage wells are present
mainly in: NY and NJ, Storm water drainage wells are used most often
in the western states. They are most frequently found in Washington,
Oregon and Arizona.
Ecological Exposures - unknown
-------
Controls - a permit is authorized by rule. Generally there are
not specific requirements, but in individual cases where wells
impact a drinking water supply permit holders might be required to
monitor etc.
Information Completeness - poor
LAND APPLICATION (WASTE WATER)
Stress Agents - nutients and toxic inorganics (heavy metals)
Potential for Exposure - 485 POTWs using spray irrigation were
;,. operatior or u..:,...i. eonoU uc Lion in 1982 (OTA 13b4;
Geographic Variability - unknown
Ecological Exposures - unknown
Controls - In general no NPDES permits are required and this source
falls into a state's nondischarge category. Operators must meet
state requirements. For E.PA grant supported projects,- the owner
must del-ineate the boundary of system install monitoring wells,
and take samples to ensure no ground-water contamination as a
condition of the grant award.
Information Completeness - poor
MATERIAL STOCKPILES
Stress Agents - Descriptive material is rare. Toxic inorganicas.
Potential for Exposure - Approximately 700 million tons of the
3.4 billion tons of material produced annually are stockpiled.
Descriptive material is rare and was acquired for only coal pro-
duction. Coal stockpiles at utilities contained approximately
185 tons in 1980 (OTA 1984).
Geographic Variability - unknown
Ecological Exposures - unknown
Controls - none
Information Completeness - poor
PIPELINES
NON-WASTE
Stress Agents - oil and petroleum products, toxic inorganics,
and inorganic acids.
-------
Potential for Exposure - In 1976 approximately 175,000 miles of
pipeline carried 9.63 billion bbls of petroleum per year in the
USA. In 1981,239 pipeline failures were reported,with 214,384
bbls lost. Of these leaks crude oil was involved in 48.1% of
the failures. Gasoline in 19.3% of the failures, liquified
petroleum gas in 14.6% of the failures,natural liquid gas in 5%
of the failures, and fuel oil in 4.6% of the failures (OTA
1984)
Geographic Variability - unknown
Ecological Exposures - unknown
Controls - not regulated by EPA
Information Completeness - poor
NONPOINT SOURCES
IRRIGATION RETURN FLOWS
Stress Agents - salts, pesticides, herbicides, and nutrients
Potential for Exposure - 51 million acres were irrigated in
1978. Approximately 169 million acre-feet of water were used
for irrigation in 1980 (OTA 1984).
Geographic Variability - Irrigation is most common in the'
West, the Central and Southern Plains, Arkansas, and Florida
(OTA 1984)
Ecological Exposures - lakes, streams and wetland. Frequency
and duration of the exposure unknown.
Controls - none
Information Completeness - poor
FERTILIZER APPLICATION
Stress Agents - nutrients
Potential for Exposure - In 1982-83 farmers used 42.3 million
tons of commercial fertilzers. Fertilizers used in 1981-82
contained 11.1 million tons of nitrogen,4.8 million tons of
phosphates, and 5.6 million tons of potash. In 1978 approximately
229 million acres were treated with commercial fertilizers and
17 million acres were treated with lime (OTA 1984)
Geographic Variability - The five states using the most fer-
tilizer between 1981-1983 were: Illinois, Iowa, California,
Indiana, and Texas (OTA 1984).
Ecological Exposures - lakes, streams and wetland. Frequency
and duration of the exposure unknown.
-------
Controls - none
Information Completeness - poor
ANIMAL FEEDING OPERATIONS
Stress Agents - nutrients and microbes
Potential for Exposure - It is estimated that all livestock on
feedlots and farms produce 175 million dry tons of manure
annually and tha*. 9P* of il. is r^tiirncr". to the land ( OTA
19U4).
Geographic Variability - Feedlots are located primarily in the
Corn Belt and the High Plains (OTA 1984).
Ecological Exposures - lakes, streams and wetland. Frequency
and duration of the exposure unknown.
Con-trols - surface discharges NPDES, ground water unknown
Information Completeness - poor
DE-ICING SALTS APPLICATIONS
Stress Agents - salts and toxic inorganics
Potential for Exposure - In the winter of 1982-83 an average of
15.5 tons of dry salts and abrasives and 2.9 gallons of liqiud
salts were applied per lane per mile of road (OTA 1984).
Geographic Variability - Confined to the snow belt especially
the populous ares of the Northeast Midwest ( OTA 1984 ).
Ecological Exposures - lakes, streams and wetland. Frequency
and duration of the exposure unknown.
Controls - some states and locals regulate application rates
Information Completeness - poor
URBAN RUNOFF
Stress Agents - toxic inorganics and toxic organics, nutrients
microbes and petroleum products.
Potential for Exposure - 21.2 million urban acres contributed to
stormwater runoff in 1970.This figure is projected to increase to
32.6 million acres by the year 2000 (OTA 1984)
Geographic Variability - concentrated in urban areas
Ecological Exposures - lakes, streams and wetland. Frequency
and duration of the exposure unknown.
-------
Controls - new Federal regulation for industiral run off.
Local run off controlled by municipal ordinances.
Information Completeness - poor
PRODUCTION WELLS (Oil, geothermal and heat recovery, and water supply)
Stress Agents - toxic inorganics and toxic organics
Potential for Exposure - Approximately 548,000 oil wells
produced an estimated 3.1 billion bbls of crude oil in 1980.
More than 37C.HCC irrio?.«-icn wri.1" are used to supply approxi-
mately 126,QUO farms in the United States (OTA 19b4).
Geographic Variability - Oil wells are clustered in the Southwest,
Alaska, Louisiana, Wyoming, and the MidWest. Geothermal activi-
ties are primarily in the West and the heavily populated northern
states where the use of earthcoupled heat pumps is increasing.
It is estimated that the greatest number of water supply wells
are in the Southwest, the Central Plains,Idaho and Florida.
(OTA 1984) .
Ecological Exposures - unknown
Controls - state permits
Information Completeness - poor
SALT WATER INTRUSION (over drafting)
Stress Agents - salt
Potential for Exposure - Approximately 21 billion gallons of
ground water are withdrawn in excess of recharge capacity
daily. This is 26% of all ground water withdrawn (OTA 1984).
Geographic Variability - Excess overdraft occurs mainly in
coastal areas(California, Texas, Louisiana, Florida, and New
York), the Central Plains, and the Southwest (OTA 1984).
Ecological Exposures - unknown
Controls - Municipal caps on pumping rates
Information Completeness - poor
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EVALUATION
The overall potential ecological risk associated with "other
sources of ground-water contamination" is enormous because of the
large number of sources and the lack of strict regulatory programs
for many of them. This threat is somewhat tempered because
ecological impacts occur only when ground-water contaminated by
these sources is released from an aquifer in sufficient volume
and concentration to effect organisms or chemical processes.
Additionally, the filtering properties of soils and the dilution
and dispersion process of streams, estuaries, coastal waters and
lakes can also reduce ecological and risk posed by ground-water
contaminants. Finally, although ecological risk from contaminated
ground water can be guite high at the ecosystems level, data does
not exist which enables one to determine the total number of
incidents on a reqional, national or global level making it
impossible to verify what the actual risk is compared to potential
risk.
If all "other sources of ground-water contamination" are
combined, the stress agents released into aquatic and wetland
ecosystems consist of toxic organics, pesticides, toxic inorganics,
nutrients, microbes, acids, oil and petroleum products. All
these stress factors, with the exception of nutrients, have been
rated as having a high ecological e'ffect on all types of fresh-
water ecosystems and estuaries. These are the systems in which
you would expect the greatest risk from "other sources of ground-
water". For wetlands, Cornell rated these stress agents as
medium to high. Specific contamination incidents such as Kesterson
Reservoir, where irrigation return flow caused selenium to leach
into a wildlife refuge which resulted in waterfowl deaths and
genetic abnormalities, verify the severe local impact contaminated
ground water can have. BLM (1986) indicates that the potential
for 100's of such sites exist throughout the country. However,
one must also consider that septic tanks, the most common type of
other source of ground water contamination both in number and
discharge volume of release mainly nutrients which Cornell ranked
as causing medium risks to most ecosystems.
Based on Cornell's analysis of stress agents, the number and
distribution of sources, documented incidents and likelihood of
discharge to ecosystems. I ranked risk from "other sources of
ground-water contamination" as medium for all aquatic and wetland
ecosystems and estuaries. Coastal waters and terrestrial ecosystems
would be ranked low. The latter has been included as low because
contaminated springs could impact terrestrial animal populations
drinking the spring water.
I also suggest a medium overall rating because even though
the ecological impacts from this source are mainly at an ecosystem
level, data does not exist to determine the number of such local
incidents occurring nationally.
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BIOLIOGRAPHY TO DATE
ICF Incorporated 1986. Analysis of the Definition of Ecologically
vital Ground Water Under the Proposed Ground-Water Classification
Guidelines., Washington D.C.
Stone,Paula J., Joan Harn, Howard Levenson, Francine Rudoff 1984.
Protecting the Nation's Ground Water from Contamination. OTA.
Washington D.C.
-------
Pesticides: Comparative Ecological Risk
Part I
Approximately 50,000 pesticide products, derived from
about 600 basic chemical ingredients, are registered for use
by EPA. About 3.5 billion pounds of formulated pesticide
products (1.2 billion pounds of active ingredients) are used
each year - 79 percent by agriculture, 15 percent by industry,
and 6 percent by households. Farmers are the biggest users
of pesticides, accounting for about two-thirds of all
pesticides used.
As a class, pesticides are at the same time among the
most beneficial and the most hazardous of substances. Agri-
culture depends upon pesticide products to protect crops from
insects, mildew, plant disease, and other pests. Health
officials need them to control the spread of diseases carried
by mosguitoes and other insects. On the other hand, because
pesticides are designed to kill living organisms, unintended
exposure to them can be very destructive, especially to biotic
receptors (e.g., fish and wildlife) in the agroecosystem.
The agroecosystem (e.g., croplands, range and pasture
land, forested areas) is very important in that it produces
the bulk of the food used for human consumption and it also
produces the preponderance of our fish and wildlife (ODUM,
1971). The small field agricultural systems of the upper
Midwest and South, characterized by small agricultural fields
bordered by strips of brushy habitat, are ideal for "growing
wildlife" because of the larger amount of edge or ecotone
which is important for maintaining ecological diversity.
Thus, this agroecosystem is very important because it produces
our food and maintains to some extent, ecological diversity.
Unfortunately, the use of pesticides to increase food produc-
tion puts fish and wildlife at risk.
Most of the agroecosystem in the United States is
treated with pesticides at least once per growing season;
in many instances there are multiple applications throughout
the year. Pesticide-treated crops are grown in just about
all biomes: e.g., grain and alfalfa in deserts; gardens in
the tundra; lumber in boreal forests. The aguatic portion of
the agroecosystem is directly treated with pesticides (e.g.,
aguatic herbicides, mosguito larvicides) and also receives
agricultural runoff laden with pesticides. These freshwater
systems ultimately lead to coastal and estuarine systems which
can become contaminated with pesticides. In addition, coastal
and estuarine systems receive direct input from many uses of
pesticides (e.g., use of TBT in antifouling paints).
-------
Fish and wildlife are directly exposed to pesticides
through inhalation, ingestion, and dermal absorption. Residues
on food - plants, seeds, insects, earthworms, smaller organisms
and water - and in their habitat result in direct exposure to
pesticides. Certain pesticides bioaccumulate and contaminate
food chains.
These exposures lead to direct effects on nontarget
organisms. Acute poisonings lead to direct mortality or
cause a decreased ability to function leading to mortality
from some other cause (e.g., predation). Exposure can cause
chronic effects like decreasing the ability of an animal to
function normally (e.g., foraging behavior, breeding behavior,
thermoregulation) or cause reduced reproductive success.
Certain pesticides (e.g., herbicides and rodenticides) cause
habitat degradation via loss of the plant and animal food
base. These types of effects on individual organisms within
systems can cause effects on the system itself. These effects
can induce a reduction or alteration of species diversity,
impact on food chains which can alter energy flow and nutrient
cycling, reduce habitat quality and the alteration of physical
resources via degradation of air, water, and soil qualities,
and impact on the stability and resiliency of the agro-
ecosystem.
Part II
Source Terms
For water and terrestrial sources, the definition given
to the stress agent - pesticides and herbicides - has a sig-
nificant impact on whether a particular ecosystem is affected
by the stress agent from an ecological viewpoint.
Water Source
Pesticides and Herbicides include agricultural biocides
that are applied directly, exported (via surface water runoff),
and transported via drift from target agroecosystems.
OPP data (NPIRS) indicate that there are at least 121
pesticide active ingredients registered for direct application
to streams, lakes, ponds, estuaries, and coastal ecosystems.
The definition also does not address direct impact of pesti-
cides and herbicides to aquatic ecosystems due to drift from
terrestrial agroecosystems. OPP estimates that approximately
10 percent of the amount of a pesticide or herbicide applied
via air or mist blower ground equipment will reach adjacent
aquatic ecosystems (EPA-540/9-86-167, p. 20). The drift
source can have significant impact on the biota in the eco-
system (Nigg et al., 1984). Further, when pesticides and
herbicides are applied via air to forest ecosystems, there
-------
is an unavoidable direct application to aquatic ecosystems
such as small streams, ponds, and estuaries. Approximately
137 pesticide active ingredients are registered for applica-
tion to forest ecosystems (NPIRS).
Terrestrial Source
Pesticides and Herbicides include applications directly
to terrestrial ecosystems or by drift from agricultural appli-
cations; transport by surface and groundwater systems are
considered elsewhere.
The "agroecosystem" is an important ecosystem which can
be significantly affected, not only by land use changes, but
also by manipulation, e.g., the use of pesticides and herbi-
cides. "Perhaps no human activity has a more profound impact
on American wildlife than has agriculture. Today 20 percent
of the continental United States is in cropland, and another
25 percent is in pasture" (Wildlife and America 1978:89). "The
agricultural and forest industry is the largest modifier of the
lands and water that provide habitats for fish and wildlife.
The size, scope, and nature of agricultural practices such as
cultivating cropland, grazing rangeland, and harvesting forests
have profoundly affected the quality of these habitats (National
Research Council 1982:xv). Further, "Agricultural activities on
cropland,^rangeland, pasture, and forest land have been altering
wildlife habitat, in both positive and negative ways, through-
out America's history" (Ibid:3). "Croplands [are] the most
intensively managed of all agricultural lands and the most
ubiquitous habitat type . . . Even though croplands are no
longer pristine areas, however, all but the most intensively
manipulated are capable of supporting some wildlife" (Ibid:92).
Thus, the terrestrial agroecosystem today is very
important from an ecological viewpoint both from the fact
that cropland, pastures, and rangeland occupy a large percen-
tage of the U.S. land area, and from the fact that the agro-
ecosystem provides important habitat for the preponderance of
our wildlife species. Further, pesticides are used to the
greatest extent on this ecosystem. While approximately 33
pesticide and herbicide active ingredients are currently
registered and applied directly to rangelands, the large
majority of the 600 pesticide and herbicide active ingredi-
ents are registered for use and applied directly to croplands
(NPIRS). OPP also found that at least 137 pesticide and
herbicide active ingredients are applied directly to forest
ecosystems (NPIRS).
What does this say about the potential effects of
pesticides and herbicides on terrestrial ecosystems such as
the agroecosystem, forest, rangeland? Following are a few
case studies that show ecological effects on the biotic
-------
components of terrestrial ecosystems, specifically avifauna,
from pesticides. (1) Diazinon is a broad spectrum pesticide
used to control a variety of insects on a variety of sites
including agriculture, grassy areas such as golf courses and
sod farms, ornamental nurseries, around commercial establish-
ments, and homes and gardens. EPA received approximately
86 bird kill reports from at least 18 States. This included
data on the potential reduction of a local population of
Atlantic Brant Geese. Further, in consultation with the Fish
and Wildlife Services' Office of Endangered Species, EPA con-
cluded that two endangered species would likely be jeopardized
by the use of diazinon on grassy areas such as golf courses
and sod farms: the Hawaiian Goose (Branto sandvicensis) and
the Mohave Tui Chub (Gila ficolor Mohavensis). After careful
review by EPA, diazinon use on golf courses and sod farms was
cancelled by EPA on September 24, 1986 based on data that show
exposure to diazinon applied on these sites results in unrea-
sonable risk to birds. The Federal Insecticide, Fungicide,
and Rodenticide Act (FIFRA) Scientific Advisory i^anel supported
EPA's action [see the following EPA Documents: EPA Environmen-
tal News, September 24, 1986; FR Notice (OPP-30000/47A);
Diazinon Support Documents, OPP, December 1985]. (2) Field
data indicate that black-billed magpies (Pica pica) were killed
by the pesticide famphur used as a pour-on to control cattle
workers (Hypoderma sp). The magpie population decline that
occurred throughout most of the western pastureland areas was
temporarily correlated with the appearance of famphur as a
cattle grub treatment (Henny et al., 1985). (3) In 1975, vast
areas of New Brunswick (Canada) forests were sprayed with com-
binations of the pesticides phosphamidon, fenitrothion, amino-
carb, and trichlorofon to control spruce budworm. The direct
sprays to the upper canopy resulted in total bird mortality
of greater than 3 million. The dead birds represented
26 species in six families, with Parulidae being well repre-
sented since warblers numerically comprise 50 to 65 percent
of the avifauna complex of the forest stands sprayed. The
data support the conclusion that songbird populations were
adversely affected in the sprayed areas comprising approxi-
mately 2.7 million ha in New Brunswick alone (Pearce et al.,
1976). (4) EPA has recently initiated a Special Review of
the pesticide carbofuran in its granular formulation. Based
on a large volume of scientific data reviewed by the Agency,
EPA has concluded that granular carbofuran is highly toxic to
avian wildlife and its use results in significant fatalities
of many small species of birds and also secondar}' poisoning of
birds of prey. Carbofuran is a major pesticide used primarily
on corn. Annual domestic usage was estimated at 10 to 11 mil-
lion pounds active ingredient; approximately 60 percent used on
corn; 20 percent on sorghum; in 1982, approximately 82 million
acres were planted in corn for all purposes (USDA, 1983 Agri-
cultural Statistics). In addition, the Agency has supporting
data to conclude that the use of carbofuran can reasonably be
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anticipated to at least contribute to significant local,
regional, or national population reductions in some bird
species, especially birds of prey and endangered species [See
FR Notice (OPP-30000/48) Carbofuran; Special Review of Certain
Pesticide Products].
Summary
Based on the above information concerning the effects of
pesticides on the terrestrial ecosystem, OPP believes that
(1) agricultural land (including cropland, pasture, and range-
Ian dTsh^uTd~^be~TncTu"ded in any list of terrestrial ecosystems;
(2) the potential scale of effect and detail of terrestrial
ecosystem-level effects for pesticides and herbicides under
terrestrial sources is high; (3) ecological effects from direct
application and drift can be very significant over extensive
areas of forests, agricultural lands, and grasslands, with
important ecological effects primarily involving biocides
affecting nontarget organisms at the population level.
Effects at the community level are also possible.
Part III
Summary of Ecological Effects From Pesticides;
Ecosystems
A. Freshwater
Streams
- There are approximately 31 active ingredients
applied directly to streams for pest control and
stream management. These are highly toxic
pesticides.
- Streams will receive direct application of toxic
pesticides for forest sprays (approxiamtely 137
active ingredients).
- Significant runoff impact on streams from highly
toxic and somewhat persistent pesticides used on
agricultural crops, from grains, vegetables, fruits,
nuts, etc.
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Lakes
- Approximately 55 active ingredients are applied to
lakes for pest control and lake management. These
are highly toxic pesticides.
- Usually only small portions of the lakes are
treated.
- The runoff impact is similar to that for streams
except that the dilution factor is much greater
for lakes.
- Portions of lakes will receive direct sprays
(drift) from pesticide applications to forests.
B. Marine and Estuarine
Deep Oceans
- No direct pesticide applications.
- Direct discharge of some biocides from ships.
- Great dilution factor.
Coastal Waters
- Few direct pesticide applications (21 active
ingredients registered for application to beaches
moderately toxic).
- Direct discharge of highly toxic and relatively
toxic pesticides like TBT and Cu (antifouling
paint persistent, and cooling towers); PCP and
other biocides from cooling tower direct discharges;
offshore drilling and ship discharges of biocides.
- Presence of productive mollusc and fishery beds.
- Runoff from agricultural lands but filtered through
estuaries and tidal wetlands.
- Large dilution factor.
6
-------
Estuaries and Tidal Wetlands
- Direct application of highly toxic insecticides
and herbicides (35 active ingredients) for uses
like mosquito control, plant growth control.
- Direct discharge of pesticides from cooling towers,
antifouling paint use, wood preservatives, etc.;
pesticides like TBT, Cu, PCP are highly toxic to
persistent.
- Direct runoff of highly toxic and persistent
pesticides used on agricultural lands (e.g., rice,
soybeans, cotton, truck farms, etc.).
- The only difference between estuaries and tidal
wetlands might be their flushing rates with
estuaries having more and tidal wetlands less.
The difference is not considered significant in
this analyis.
C. Terrestrial
Agricultural Land
- Direct application of the most highly toxic and
persistent insecticides, herbicides, and fungicides,
- Multiple applications, especially during the
growing season(s).
- Primary hazard to terrestrial organisms (especially
birds); but runoff and drift poses a hazard to
aquatic organisms.
- The number of active ingredients would be greatest
in this category.
Deciduous and Coniferous Forests
- Direct application of highly toxic pesticides for
forest pest control.
- Both terrestrial (especially upper canopy) and
aquatic organisms (small streams) will be exposed.
-------
- Herbicides used in forest management practices.
- Approximately 137 pesticide active ingredients can
be applied to forests in general.
Grasslands (Nonagricultural)
- Direct application of highly toxic and somewhat
persistent insecticides and herbicides to control
pests.
- Usually no more than 1 to 2 applications per
treatment.
- About 33 active ingredients were found for direct
applications to rangelands alone.
- Primary concern is for terrestrial organisms.
- Runoff and spray drift will expose aquatic organisms.
Desert/Semiarid
- Few chemicals applied directly to deserts; some
for rangeland pest control would be also applied
to desert fringes; mostly herbicides.
- Little runoff.
- A lot of semi arid land irrigated and turned into
productive agricultural cropland and pasture. In
this case, comments on agricultural land would
apply here also.
Tundra
- Few direct pesticide applications.
- Exposure limited to aerial transport and some
limited runoff.
- Localized use of pesticides and herbicides.
D. Wetland
Wetlands
- Direct application of highly toxic insecticides
and herbicides for uses like mosquito control,
plant growth control.
8
-------
- Runoff and drift from agricultural pesticide use
which include highly toxic and persistent
insecticides, herbicides, and fungicides.
- Aquatic organisms will likely receive greatest
impact; some impact on terrestrial organisms.
- Moderate dilution.
Literature Citation, Data Sources
Council on Environmental Quality. (1978) Wildlife and America,
Howard P. Brokaw, Ed. 532 pp. U.S. Gov. Printing Office,
Washington, D.C.
Henny, C.J.; Blus, L.J.; Kolbe, E.J.; Fitzner, R.E. (1985)
Organic phosphate Insecticide (Famphur) Topically Applied
to Cattle Kills Magpies and Hawks. J. Wildl. Manage
49(3):648-658.
National Research Council. (1982) Impacts of Emerging
Agricultural Trends on Fish and Wildlife Habitat, National
Academy Press, Washington, D.C. 303p.
Nigg, H.L.; Stamper, J.H. Queen, R.M.; Knapp, J.L. (1984)
Fish Mortality Following Application of Phinthoate to
Florida Citrus. Bull. Environ. Contain. Toxicol. 32:587-
596.
NPIRS, National Pesticide Information Retrieval System.
Odum, E.P. (1971) Fundamentals of Ecology, Third Edition,
W.B. Saunders Company, Philadelphia, London, Toronto.
574 p.
Pearce, P.A.; Peakall, D.B.; Erskine, A.J. (1976) Impact on
Forest Birds of the 1975 Spruce Budworm Spray Operation in
New Brunswick. Progress Notes, No. 62, March 1976, Canadian
Wildlife Service, 7p.
U.S. EPA. (1986? June) Hazard Evaluation Division Standard
Evaluation Procedure - Ecological Risk Assessment. Office
of Pesticide Programs, Washington, D.C. 20460. EPA-540/9-
86-167.
USDA. (1983) Agricultural Statistics.
9
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ECOLOGICAL RISK WORKGROUP PROBLEM #28:NEW TOXIC CHEMICALS
More than seven thousand new chemicals have been developed for
industrial uses in the United States since 1979. At least half of them are
believed to be in production currently and available through regular
commercial markets. While manufacturing and processing procedures and use
and disposal practices associated with industrial chemicals result in
accidental as well as planned releases to the environment, less than 10
percent of those chemicals have been subjected to even minimal laboratory
testing to assess their toxicity to aquatic and terrestrial life.
While data on the subject have not been assembled, it appears that most
environmental releases of industrial chemicals from manufacturing and
processing operations occur through point source discharges to receiving
streams, directly or following some level of treatment in a POTW. Point
source discharges also appear to be the main origin of environmental
releases of industrial chemicals from use sites, although certain use and
disposal practices may result in some non-point source releases.
Atmospheric releases also are possible during manufacturing, processing,
use and disposal of volatile chemicals.
There is uncertainty involved in assessing the sites, amount, frequency
and duration of releases of new chemicals to the environment. Initial
release and exposure assesments performed during the evaluation of new
industrial chemicals under Section 5 of The Toxic Substances Control
Act (TSCA) are based on calculations and estimates made before
manufacturing of the chemicals is initiated. Monitoring data on releases
of new chemicals are not routinely required of manufacturers and users and
-------
usually are not available. The expense of environmental monitoring and the
lack of adequate detection methods contribute significantly to the absecnce
of such data, also.
New industrial chemicals which are toxic may pose a risk to both
terrestrial and aquatic life depending upon the time place, magnitude and
duration of the exposure. Since releases to receiving streams are a
standard practice in the manufacturing, processing and use of industrial
chemicals, aquatic life appears to be exposed much more frequently than
terrestrial life and over a larger geographical area. Data have not been
collected and analyzed, however, to support and better characterize the
temporal aspects and relative magnitude and frequency of terrestrial and
aquatic exposures to industrial chemicals.
The response of aquatic and terrestrial populations to exposure by a
toxic industrial chemical will vary depending on the toxicity of the
chemical, the nature, magnitude and duration of the exposure and the
physical and chemical conditons exisitng at the time. The response may be
direct or indirect. The exposure may cause acute mortality in all or a
portion of the population or community or it may cause reproductive
impairment or sublethal,but adverse effects, to exposed organisms.
Structural as well as functional units of the exposed ecosystems may be
damaged or destroyed,and that damage may be transient or permanent.
NEW TOXIC CHEMICAL SOURCES, RELEASES AND EXPOSURES
Sources and Releases
TSCA provides information on sources of new industrial chemicals, their
-------
416 now chemicals were reviewed by OTS. The annual production of
approximately 3 percent of those chemicals was estimated to be greater than
5 million kilograms. Production volumes between a million and 5 million
kilograms were calculated for 12 percent of the chemicals, 500,000 to one
million killorgrams for 8 percent, 100,000 to 500,000 kilograms for 22
percent, and 1,000 kilograms or less for 19 percent of the chemicals
reviewed.
Production volume information available for new chemicals at the time
of the Section 5 review, such as that just cited, is based on intended, not
actual, production figures and it may overestimate or underestimate
significantly the real production volumes. The difference between the
calculated and real production figures may in turn lead to significant
errors in the OTS exposure assessments. Nevertheless,unless specifically
notified to the contrary, manufacturers are not required to inform OTS of
subsequent changes in production volumes when manufacturing commences.
Industrial chemicals may be released to the environment from
manufacturing and processing facilities and use and disposal sites. Some
uses and certain disposal practices may result in releases from non-point
sources. Accidental releases from spills may also occur although spills are
not considered currrently by OTS in its environmental exposure assessments.
For the most part, however, it appears that most releases to the
environment will originate from point source discharges.
Exposures
The quantity of an industrial chemical reaching the environment depends
-------
on a number of variables, including manufacturing and processing practices,
treatment of the industrial discharge before release to a receiving stream
and the effectiveness of that treatment, the properties and characteristics
of the chemical and the volume of chemical being manufactured and
processed. Some or all of these parameters may vary from one chemical to
another.
A variety of other factors influence the nature of environmental
exposures which result when an industrial chemical is released to the
environment. Included among those factors are the temporal aspects of the
release, the persistence of the chemical, the frequency of the releases and
the properties of the chemical which affect its fate and movement once it
enters the environment. The accuracy of the environmental exposure
assessments for new industrial chemicals depends on the accuracy of the
information available concerning the expected releases and the fate of the
chemical in the environment.
Manufacturing and processing sites for any particular chemical usually
are limited to a few locations, frequently no more than one or two. The
site or sites at which a chemical is to be manufactured and processed are
identified during the Section 5 review, and in some instances, the use
sites are known as well. However, once the chemical passes the Section 5
review and is placed on the TSCA Inventory, it may then, unless otherwise
restricted, be manufactured and processed by anyone at other sites
throughout the country and in any quantity.
Many of the new industrial chemicals are intended for widespread use
and, to the extent they are used widely, they may be released to the
environment at a large number of sites. Many of the manufacturing,
processing, use and disposal sites may also release to the environment a
variety of other industrial chemicals, some of which may act in an additive
-------
manner with the new chemicals to increase the toxicity of one or both and
thus increase the potential for environmental damage to occur. At the
present time, the OTS exposure assessments do not consider the additivity
of other industrial chemicals entering the environment from the same or
other sites.
Since exposure information on industrial chemicals not yet in
production is based on calculations and estimates which are subject to
uncertainty and since monitoring data on most industrial chemicals are not
being developed voluntarily by manufacturers and processers, exposure
assessments for new industrial chemicals are, at best, subject to the same
uncertainty. Moreover, no mechanism is in place currently to verify the
accuracy of the conclusions of the Section 5 reviews regarding the
potential for adverse ecological effects.
Quality and Completeness of Information
Premarket testing of new industrial chemicals is not a routine
requirement in the U.S. Consequently, ecotoxicity data and exposure
information available for use in a Section 5 review for ecological effects
are extremely limited.
Ecotoxicity Data :
o Ecotoxicity data are available for less than 10 percent of
the new chemicals reviewed by OTS since 1979.
o Ecotoxicity data adequate for a reasoned ecological risk
assessment are available for less than 5 percent of the new industrial
chemicals introduced into U.S. markets since 1979.
o Quantitative structure activity relationship (QSAR) models
are available for estimating the minimum toxicity of approximately 30 to 40
-------
percent of the chemicals reviewed under Section 5, excluding polymers. If
the models are properly applied, the minimum to'xicity estimates are
suitable for screening evaluations but not for definitive ecological risk
assessments.
o QSAR models are available for estimating bioconcentration
factors for industrial chemicals. If the QSAR models are used properly, the
estimates they provide are generally good predictors of bioconcentration.
However the models cannot be applied to industrial chemicals which have
high octanol/water partition coefficients. Industrial chemicals having high
octanol/water coefficients frequently are of environmental concern because
of possible chronic toxicity and bioconcentration.
Exposure Data:
o Little if any environmental fate test data are available
for chemicals undergoing Section 5 reviews.
o Data bases and techniques are available for estimating many
environmental fate parameters on the basis of chemical and physical
properties. The accuarcy of these estimations, however, seldom are
verified.
o Release estimates include a number of uncertainties
resulting from the use of calculations in place of experimental data.
o Several models are available for assessing the potential
exposure of ecological systems to industrial chemicals. The outputs of the
models, however, are subject to the same uncertainties as the release
estimates.
Risk Assessments of New Chemicals:
-------
o Ecological risk assesments of new chemicals under Section 5
are based on the so-called "quotient method" which involves comparing the
estimated environmental concentration to a concentration of the chemical
estimated to cause a specific effect. The quotient method provides no
information regarding important indirect effects of chemicals on ecological
system. It also does not take into account other direct effect endpoints.
o Current ecological risk assessment methods do not provide a
range of options for risk management.
STATUS OF CURRENT AND REASONABLY PROJECTED CONTROLS
Controls to safeguard the environment against the adverse effects of
new industrial chemicals provided by Section 5 reviews are effective only
in those instances where there is enough information to adequately assess
the toxicity of the chemical and the nature of the releases to the
environment.New chemicals which have passed through the Section 5 review
and are placed on the TSCA Inventory without restrictions can then be
manufactured, processed, used and disposed of in any quantity, at any
location and by any manufacturer.
In 1986, for example, 118 chemicals suspected of being toxic to aquatic
life were dropped from further Section 5 review because premanufacture
production, processing and use information indicated that there would be no
environmental releases or that releases which might occur would not result
in environmental concentrations great enough to cause environmental damage.
However, because exposure estimates developed during the Section 5
review were based on specific conditions such as production and processing
methods, production volume, and use and disposal practices, any changes in
-------
those parameters could result in releases which would be damaging to the
environment.
Since new industrial chemicals which go on the TSCA Inventory without
restrictions are not routinely tracked, there is no opportunity to prevent
environmental damage resulting from changes in the exposure parameters.
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PROBLEM #28 : NEW TOXIC CHEMICALS
INFORMATION SOURCES
o Monthly PMN and TMEA Statistical Summary-Report for September 1986.
Premanufacture Notice Management Branch, Chemical Control Division.
o CBI PMN Statistics Report for 3rd Quarter of FY 85.
o Analysis of Withdrawn and Voluntarily Tested PMNs. Centaur
Associates, Inc. 1985.
o Analysis of TDIS Data on PMNs by Use, Chemical Function and
Production Volume. Centaur Associates, Inc. 1983.
o Chemical Control in the United States. Accomplishments Under the
Premanufacture Notice Management Program. Office of Toxic Substances
1987.
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EVALUATION OF PROBLEM : NEW TOXIC CHEMICALS.
STRESS AGENT SCALE OF EFFECT
BIO- REGION- ECO- BUFF.
(SOURCE) SPHERE AL SYSTEM LAKES
FRESHWATER ECOSYSTEMS
UNBUF. BUFF. UNBUFF
LAKES STREAM STREAM
AIR
WATER
TERRESTRIAL
OTHER
7
L
L
7
7
M
L
7
7
H
7
7
7
H
C
7
7
H
C
•p
7
H
C
•p
•p
H
C
•p
AIR ?
WATER L
TERRESTRIAL L.
OTHER ?
7
M
M
7
7
H
H
7
MARINE & ESTUARINE ECOSYSTEMS
COASTAL OPEN OCEAN ESTUARIES
M
M
7
H
H
•?
AIR L
WATER L
TERRESTRIAL ?
OTHER
L
L
7
L
L
TERRESTRIAL ECOSYSTEMS
CONIF. DECID. GRASS'LDS. DES./S.A. AL'P/T
AIR
WATER
TERRESTRIAL
OTHER
7
H
7
7
H
M
WETLAND ECOSYSTEMS
FRESHWATER SALT-
ISO ' L . /UNBUF . ISO'L./BUF. FLOWING WATEF
? ? 7 7 7
H H H H H
77 7 77
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Ecological Risk from Biotechnology^
Introduction
Included under the topic "biotechnology," as related to OPTS
issues, are microbial pesticides and genetically engineered
organisms. Microbial pesticides include bacteria, blue-green
algae, fungi, viruses and protozoa. Genetically engineered
organisms include organisms that are genetically modified to contain
genetic material from dissimilar source organisms.
EPA has chosen to focus, both under FIFRA and TSCA, on
microorganisms that are used in the environment, are pathogens, or
contain new combinations of traits (e.g. contain genetic material
from dissimilar sources or are nonindigenous to areas where release
and use is intended). EPA believes these categories have
sufficiently high potential for widespread exposure and adverse
effects or great uncertainty concerning potential effects as to
merit close regulation under OPTS statutes. Identifying these
subsets of biotechnological products is an attempt by EPA to
separate products on the basis of potential risk.
Uniqueness of Risk from Biotechnology Products
Traditionally, ecological risk assessment for most pesticides
and many toxic substances focuses on geographically defined areas of
use, exposed habitats and the potential for adverse effects to
organisms in the area.
Typically, crop sites and use areas have been used to identify
the application and exposure areas. Off-site transport is assumed
to occur via aerial drift, run-off, leaching and bioaccumulation.
In a few cases aerial drift has been obserrved to transport residues
many miles off-site. In the majority of cases however, ecological
effects have been considered more or less restricted to defined
areas of impact.
Pesticides and toxic substances derriving from biotechnology
pose a different sort of ecological hazard. This is primarily
due to their effects on organisms of specific taxonomy,
regardless of geographic location. For example, the risk from a
given engineered pathogen may be to all lepidopterans irrespective
of range because the pathogen is host-specific, capable of wide
distribution and not restricted to a specific eccosystem, life zone,
crop site or habitat. As such, risk must focus on organisms, entire
species, families, and higher taxonomic groupings. Risk assessment
predicated on these effects is a new undertaking by OPTS, and is
largely untried todate. Ecological effects due to biotechnologically
derrived products are unpredicable and potentially of global impact.
Traditional concepts of assessing hazard by ecosystem may not be
the most useful framework for assessing risks from these new products
New approaches should be sought and risk assessment should be
tailored to fit the new kinds of risks posed by biotechnology.
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-2-
Kature of Risk from Biotechnology Products
Latency of Adverse Effects
Certain bacteria, fungi, protozoa and viruses can require
a long incubation or latent period before pathogenic effects are
observed. Acute, short-term tozicity tests might not be sufficient
to detect these effects.
Environmental Releases
Although many microorganisms will be biologically contained
by inherent limitations on their growth and survival, some may
reproduce and increase in numbers in the environment beyond the amounts
originally released. Some will also have independent mobility, or
may spread beyond the area in which they are intended for use.
Nonindigenous Microorganisms
It is difficult to predict whether a nonindigenous
microorganism will be subject to the physical and biological controls
present in the environment where it is to be introduced. Examples of
nonindigenous microorganisms (pathogens) that have caused significant
adverse effects are chestnut blight fungus and Dutch elm disease fungus
Microorganisms with New Traits
Microorganisms with new trailts of characteristics may behave
in unpredicatable ways. Traits may be new to the organism (as a result
of genetic engineering) or traits may be new to the environment (as a
result of introduction of nonindigenous organisms). In either case
potential effects are highly unpredicable at present.
Some new traits may affect the microorganism's characteristics
of, for example, survivability, host range, substrate utilization,
competition with other organisms, or protein or polysaccharide
production. Potentially even relatively small changes in
characterises such as these may result in fundamental changes in
community composition, structure or function.
Risks to Nontarget Genetic Material
The function and behavior patterns of recombined genes is
poorly understood and unpredictable in some cases. There exists
the potential for genetic transfer to unintended recepients. The
environmental fate of genetically engineered organisms is not
clearly known, nor are the potential effects from competition with
native organisms.
-------
-3-
Evaluation of Risk
Risk nay range from zero, as when a microorganism pathogen
is short-lived and effective only against the target, to risks
of global eradication of an entire taxonomic group should a
genetically engineered organism escape it's intended use area and
function and be carried by specific hosts to all taxonomic group
members.
Thus far, reviews of small-scale field testing proposals
for genetically engineered microbial pesticides have emphasized
some questions that have not been as significant in the assessments
of naturally occuring microbial pesticides. For example, OPP has
identified potential risks associated with the transfer of inserted
genetic material to other organisms, the competitiveness of the
engineered organism compared to the parental organisms in the
environment, and the ability of.the engineered organism to become
•stablished in a new ecological niche and thereby pose a potential
adverse impact to the environment.
Risk evaluation for biotechnological products is in it's first
stages and is inherently filled with uncertainty and the need to
develop -new frameworks for evaluation. Old criteria may not be
applicable and new concepts for assessing risks to entire taxonomic
groups need to be developed. Much basic research in risk assessment
and risk management is needed in this area.
B ibliography
Federal Register, Thursday, June 26, 1986s 23321-23324
Ghassemi, M. et al. 1983. Environmental International. (9): 39-49.
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Ecoloqical Risk Workgroup
Problem #30: Plastic in the Marine Environment
Overview
Plastic has become a dominant ingredient in the composition
of modern household qoods, furnishings, packing materials, tools,
eguipment and machinery. Although plastic was invented only a
little more than 40 years ago, its presence, either as a raw
material or a manufactures product, is worldwide. Unfortunately
the features of plastic which make it so convenient and useful
also assure its persistence when released, lost or abandoned in
the environment.
Sources
While plastic material may o'rginate both 'on land and -at sea,
most of the plastic debris entering the marine environment is
believed to come from ocean sources such as shipping and
commercial fishing. Deliberate disposal at sea of plastic items
aopears to be one of the major sources of plastics entering the
marine environment. Another important source is commercial
fishing which introduces both domestic waste as well as plastic
fishing gear to the marine environment. Oil rigs and drilling
platforms are a third major source from which plastic debris
enter the ocean.
Land-based sources discharging plastics to marine
environments include industrial sites where plastics are
synthesized from petrochemicals or where plastic products are
manufactured. In metropolitan areas, primarily along the North
Atlantic coast, sewer systems combined with storm water runoff
systems contribute large amounts of plastic debris via outfalls
in marine areas. Municipal sewage sludge dumped in the ocean is
also a potential source of plastic debris.
The types of plastic debris found in the marine environment
includes both manufactured and raw plastic articles.
Manufactured articles are those which have been fabricated into
consumer products such as fishing gear, packing and packaging
materials, six-pack connectors, plastic sheeting bags, and
bottles. Raw plastics usually are in the form of small spherules
or beads, synthesized from petrochemicals and used to manufacture
-------
plastic products. Both manufactured and raw plastics enter the
marine environment by one or more routes - deliberate and
accidental discharge or dumping at specific sites, indiscriminate
but deliberate discharge or dumping in shipping canes, accidental
loss or deliberate abandonment of plastic material at sea.
Impact Responses
A growing body of evidence indicates that plastic items
discharged, lost or abandoned are adversely affecting the oceans
and marine life in a variety of ways.
The presence of plastics in the environment is a hazard to
marine life because of the potential for (1) entanglement or
entrapment and (2) ingestion of plastic materials which may be
toxic or cause physical blockage of the digestive system. Among
marine life which has suffered adverse effects from plastic
debris are several endangered and threatened species of marine
mammals, sea turtles, sea birds and marine fish. Certain
economic losses also are. associated with the presence of plastics
in the oceans including losses in commercial fisheries due to
"ghost fishing" or entrapment of fish by discarded commercial
fishing gear, cost of beach cleanup to remove plastic debris, and
aesthetic degradation of beach areas.
-------
Detailed Description of Sources, Releases and Exposures,
Sources;
Substances and quantities released -
The types of plastics found in the marine environment
include a broad ranqe of objects. Certain items can be traced to
a particular source while others may originate from several
different, and sometimes unidentifiable, sources. Whatever the
case, it is believed that most plastic debris in the marine
environment comes from ocean sources. Prominent amonq plastic
debris found in the marine environment are the following:
(1) Fishinq year
(a) nets - Most commercial fishinq nets in use today are
composed of synthetic fibers (vinylon, vinylidine, vinyl
chloride, polyethylene, polyester, polypropylenel) or
combinations of plastic fibers. Pieces of net released as a
result of damage to an intact net or discarded during, repair of
damaqed nets, or whole nets lost accidentally or deliberately
discarded at sea are found in the marine environment. Accurate
figures on the quantity of such debris, however, are not
available currently. There are, however, figures on the quantity
of plastic nettinq in use in some of the major commercial ocean
fisheries which provides an insiqht of the potential maqnitude of
the problem.
The total lenqth of all gill nets available to the 15 major
North Pacific gill net fisheries is 170, 466 km - if strunq end
to end, this is enouqh net to extend about four times the lenqth
of the equator. Commercial fisherman from Japan, Taiwan and
Korea, set out approximately 1,065,510 miles of drift net each
year. Japanese vessels fishinq for salmon in U.S. territorial
waters set out 2,580 kilometers of gill net each day.
Trawl nets, bag-shaped nets towed behind a vessel, are
believed to the second most commonly lost type of net.
Approximately 5,500 km of trawl net are used by the 12 major
foreign and domestic trawl fisheries in the North Pacific.
Desired observations of trawl net losses in 1984 revealed the
following: 322 commercial fishing vessels operating off Alaska
lost 65 nets or portions of nets in one year.
-------
Although there are no reliable estimates of the total
quantity of qill or trawl net lost or damaged, some relevant
observation has been recorded. A research vessel found 3,000 ra.
of lost qill net in the western North Pacific. In a 100 acre
plot of a major qill net fishinq qround off the New England
Coast, 10 lost qill net were found. Official records maintained
under the Fishermen's Vessel and Gear Damage Condensation Fund
list 525 gill nets, 50 feet or more in length, (30 miles) lost in
1985 and 320 (18.2 miles) in 1986. These records include only
nets lost in Federal waters.
(b ) Traps - plastic nettinq is used in the construction of
lobster, crab, and eel traps. In 1984. 2.5 million traps were
used in the New England lobster fishery; approximately 20% of
those were lost. Some 30,000 Kinq crab trap have been lost in
Alaskan waters since 1960. Along the West coast of Florida in
1984, over 25% of the 96,000 stone crab traps in use were lost.
(c) Plastic buoys and ropes - Plastic rope and buoys are put
to a variety of uses bv commercial and sports fisherman and in
various types of water recreation. There have been few attempts
to quantify the amount of rope or the number of buoys lost.
Files kept- by the Fisherman's Vessel and Gear Damage .Compensation
Fund suggests that large numbers of buoys and great quantities of
plastic rope are lost at sea. In the states of Washington and
Oregon a total of 1042 buoys and 465,906 feel of rope were
reported lost in 1985 alone. Crabbers use two to three buoys per
King crab trap; 30,00 King crab traps and at least twice that
many buovs have been lost in Alaska since 1960. Since 16,611
stone crab traps lost in the Gulf of Mexico represents a loss of
16,611 buovs and 157 miles of nylon rope.
d. Monofilament fishing line - large guantities of
monofilament fishinq line are lost or discarded overboard each
year. There are, however, no records to quantitate the maqnitude
of the problem.
e. Cargo Associated Wastes - Two items of debris orginating
from cargo shippingactivities which are known to affect the
marine environment are plastic strapping bands and large pieces
of plastic sheeting. Strapping materials are used extensively to
bind corrugated cartons containing fish, fishing nets beverage
containers and various other packing cartons. While there is no
information on the total length of strapping material produced
annually, it is believed to be considerable based on estimates of
the total amount sold in the U.S. (approximately 125 million
pounds).
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Larae sheets of plastic are used in carqo shipments to cover
items durinq transport and frequently are discarded. One pound
of this plastic sheetinq will cover 28 square feet of beach
area. Documentation is not available on the amount of plastic
sheet debris which is qenerated, althouqh plastic sheetinq has
been reported as the most abundant litter items found on at least
one seashore area examined.
f. Domestic Plastics - Plastic items used for domestic
purposes makes up a diverse cateqory of plastic found in the
marine environment. Included in this cateqory are larqe, sheets,
six-pack connectors, containers, bottles, tampon applicators and
pieces of styrofoam.
The presence of small plastic particles in the marine
environment has been documented numerous times. Included in this
cateqory are raw plastic pellets and fraqments or remanants of
manufactured plastic items. Both raw plastic pellets and plastic
fraqments have been found in hiqh concentrations (raw plastic
pellets - 34,000/Km2? and plastic fraqments - 305/Kilometer of
beach).
Location, size and number of sources
While the plastic debris found in the marine environment may
take in a broad array of items which may originate from land or
sea, it is believed that most of it comes from ocean sources.
The disposal of wastes by ocean sources is common because it is
"inexpensive" and convenient. The disposal of wastes from ocean
sources is believed to exceed 7 million meteric tons a year.
Commercial fishinq operations are a source of plastic debris in
the form of domestic wastes and fishinq qear. There are,
worldwide, 120,00 commercial fishinq vessels over five tons.
These ships qenerate about 340,00 metric tons of domestic wastes,
some part of which is plastic debris. In addition, the world's
commercial fishinq fleet qenerates annually a thousand metric
tons of plastic fishinq debris includinq nets, lines, buoys.
The world's merchant shipping fleet which consists of 71,00
ships (in 1979) disposes of approximately 11,00 metric tons of
plastic debris via domestic wastes each year, and an unknown
quantity of plastic debris amonq the 5.6 million metric tons of
carqo-waste. These merchant ships also are a source of raw
plastic pellets which are "lost" durinq loadinq or unloadinq or
which are used as packinq. Larqe passenqer vessels produce some
504 metric tons of plastic debris each year while the one million
recreational boats in the U.S., in marine waters, are the source
of 340 metric tons of plastic debris.
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There are approximately 175 off shore drilling rigs in U.S.
waters and these are the source of an underterrained amoumt of
plastic debris which enters the marine environment. The waste
plastic from these sources includes plastic sheeting, marking
buoys, plastic drums, computer write protection rings, drilling
pipe thread protectors, plastic ropes and filters.
Land-based sources of plastic wastes contributing to the
marine problem include industries which synthesize plastic and
manufacture plastic articles, wastewater treatment plants and
storm water runoff systems with outfalls in marine areas. Data
on the number of these sources and their locations have not been
assembled.
Current Controls
Legal authority exists pertaining to ocean dumping and
disposal of hazardous wastes, and regulating the taking of marine
mammals and fish. Much of it may be applicable to controlling
the kind of plastic de.bris -that results in entanglement of marine
org.anisms, but none of it addresses the issue specifically.
Included in the existing authority are laws that govern ocean
dumping, including dumping of plastics; pollution laws that
govern disposal of hazardous wastes and regulate water guality;
fish and wildlife conservation laws that regulate how fish and
marine animals may be taken by humans.
Relevant international authorities include the London
Dumping Convention, the MARPOL Protocol, the U.N. Regional Seas
Program, the United Nations Law of the Sea, and other agreements
similar in pattern to these major conventions. Each of these
authorities is aimed .at controlling dumping in the oceans.
Certain substances are prohibited expressly, and others are
permitted to be dumped under a regulatory scheme adopted by each
of the nations party to the agreements. The major concern in
relating these agreements to the entanglement issue is whether or
not dumping of plastics is covered under the prohibitions. The
key issue in using the London Dumping Convention to control
dumping of nets is whether or not a net is discarded
purposefully, or incidentally in the course of normal fishing
operations. The MARPOL Protocol, on the other hand, does
expressly denote fishing nets among prohibited disposals, and
additionally covers accidental disposals. However, Annex V,
which contains the language relevant to plastics, must be
ratified by at least 15 nations whose fleets jointly constitute
50 percent of the gross tonnage of the world's shipping. To
date, 14 nations have ratified the Annex, but their combined
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tonnaqe falls short of the requirement. The U.S. has not
ratified the Optional Annex V. A major concern with all these
aqreeraents is that enforcement is difficult and left to the
discretion of each signatory nation.
U.S. domestic legislation governing ocean or inland dumping
is typified by the Rivers and Harbors Act of 1899/ the Act to
Prevent Pollution from Ships, the Marine Protection, Research and
Sanctuaries Act (MPRSA), and the Clean Water Act. In addition to
these major authories, there are several other laws which may be
applicable in narrow circumstances. Pertinent considerations in
determinq whether these laws are applicable to entanglement
include the extent of their jurisdication, and whether or not
plastics are covered substances under the definitions of each
law. The major aurthority is the MPRSA or "Ocean Dumping Act."
However, its applicability may be limited in that it regulates
transportation for the purpose of dumping, rather than dumping
itself. The second type of authority, aimed at land-based
disposals, can be found in the Resource Conservation and Recovery
\ct'f which regulates disposal of.solid waste and prohibits
dumpinq of hazardous waste. The key question with regard to
plastics and entanglements is whether netting and other plastic
debris can be defined as "hazardous" under the law. The final
group of U.S. authorities examined is wildlife conservation
law. Under these laws, such as the Marine Mammal Protection Act,
the Endangered Species Act, the Migratory Bird Treaty Act, and
the Fishery Conservation and Management Act, it is the taking of
marine mammals and birds that is prohibited, rather than the
disposal of materials that lead to entanglement. Under each of
these authorities, entanglement would constitute a violation as
an illegal "takinq." As with other legislation, enforcement is
difficult, since the prohibited activity takes place at sea.
Each of the states has enacted legislation on the state
level to implement federal pollution control laws such as the
Clean Water Act and the Resource Conservation and Recovery Act.
The provisions of these laws are substantially the same as the
federal law, though may be more restrictive. In addition, a
series of laws known as "bottle bills" can be viewed as a
solution to one segment of the entanglement problem. These laws
in may states prohibit the sale and distribution of beverage
containers that are connected by plastic rings or-similar devices
unless the connectors are bio- or photodegradable.
There are very few existing programs that address, or have
the potential to address, the problems of plastic marine debris,
even in areas where the problems are significant. The only
federal agency that has a program specifically relating to
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entanglement is the National Marine Fisheries Service. Some
existing federal programs, such as the National Sea Grant College
Program, and the Chesapeake Bay program which resulted from a 5-
year EPA study, are potentially relevant to the problem of
plastic marine debris. Some states have programs that relate
directly to legislation, for example beach cleanup programs and
recycling programs. A limited number of private entities,
including corporate and non-profit organizations, have specific
programs relating to entanlgment or other aspects of marine
debris.
Availability and Quality of Information
Evidence is emerging that the disposal of plastic debris in
the marine environment is a serious problem for a number of
species and for communities and user groups that depend on the
marine environment. Even when the information is anecdotal, as
it is in many cases, a synthesis of such anecdotal reports
suggests that the biological and economic impacts may be
significant.
The major sources of plastic debris in the marine
environment have been identified. Unfortunately, there have been
few directed studies concentrating on particular regions or
particular populations of animals.
Management agencies, at the federal, state and local levels,
are not yet fully aware of the magnitude of this issue, and have
not directed their efforts toward investigating the biological
and economic impacts associated with marine plastic debris and
conseguentially relatively little data has been compiled or
evaluated.
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Problem #30
Evaluation of Problem
Ecosystems
Freshwater
Marine and Estuarine
Terrestrial
Wetland
Buffered Lakes
Unbuffered Lakes
Buffered Streams
Unbuffered Stream
Coastal
Open Ocean
'Estuaries
Coniferous Forest
tfeciduous Forest
Grassland
Desert/Semi-Ar id
Alpine/Tundra
Freshwater-i solated
Freshwater-flowing
Saltwater
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(1) Significance of ecological effects of plastic debris discarded, lost or abandoned.
(2) Documented presence of considerable guantities of plastic debris.
(?) (? = uncertain because of insufficient knowledge.)
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Reference
Center For Environmental Education - 1986. Use and Disposal of
Nondegradable Plasticsin the Marine and Great Lakes
Environments. (Draft - July 1, 1986).
(Major review of literature on plastics in the environment
with an extensive list of references.)
fcU.S. GOVERNMENT PRINTING OFFICEl t987-716'002/60580
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