United States
Environmental Protection
Agency
Office of Policy Analysis
Office of Policy, Planning,
and Evaluation
Washington, D.C. 20460
EPA-230-03-89-046
June 1989
&EPA Summary of Ecological Risks,
Assessment Methods, and Risk
Management Decisions in
Superfund and RCRA
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EPA-230-03-89-046
SUMMARY OF ECOLOGICAL RISKS,
ASSESSMENT METHODS, AND
RISK MANAGEMENT DECISIONS
IN SUPERFUND AND RCRA
Office of Policy Analysis
Office of Policy, Planning, and Evaluation
U.S. Environmental Protection Agency
Washington, D.C.
June 1989
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ACKNOWLEDGEMENTS
This document was developed by EPA's Office of Policy Analysis (OPA) within the
Office of Policy, Planning, and Evaluation. Dr. Craig Zamuda was the EPA project director,
with support provided by Dr. Dexter Hinckley, Mr. Mike Cox, and Mr. Ron Benioff.
ICF Incorporated assisted OPA in development of this document. The ICF project
team was directed by Steve Wyngarden, Bill Ward, Bob Hegner, and Joanne Colt, and included
Margaret McVey, Scott Redman, Simon Heart, Charles Chappell, Andrea McLaughlin, Michael
Troyer, Laura Boccuti, Steve Heurung, Baxter Jones, and Randy Freed.
The authors of this document wish to acknowledge, with appreciation, the inputs,
cooperation, and review provided by the many other people who contributed to the project.
This includes numerous individuals within the Department of the Interior (Fish and Wildlife
Service and Office of Environmental Project Review), the National Oceanic and Atmospheric
Administration, all ten EPA Regions, EPA Laboratories, EPA Headquarters, and several State
organizations.
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TABLE OF CONTENTS
Page
OVERVIEW OF REPORT i
PARTI: SUPERFUND
1. INTRODUCTION M
2. STUDY APPROACH 1-2
3. NATURE AND EXTENT OF ECOLOGICAL RISKS . 1-4
3.1 Nature of Threats at Superfund Sites 1-4
3.2 Extent of Threats at Superfund Sites 1-7
3.3 Analysis of Trends 1-7
3.4 Generalizations Concerning the Significance of Threats 1-14
4. ECOLOGICAL RISK ASSESSMENT METHODS 1-19
4.1 Screening-Level Analyses 1-19
4.2 Approaches for Characterizing Actual Impacts 1-20
4.3 Approaches for Characterizing Potential Impacts 1-25
5. SUPERFUND ECOLOGICAL RISK MANAGEMENT ISSUES . . . 1-32
5.1 When and How Ecological Risks are Considered 1-32
5.2 Biological Technical Assistance Groups 1-34
5.3 Ecological Risk Management Issues and Impediments 1-34
6. SUPERFUND PROGRAM IMPLICATIONS AND
OPPORTUNITIES 1-37
6.1 Implications 1-37
6.2 Opportunities for Further Study and Program Improvements .... 1-38
PART II: RCRA
1. INTRODUCTION II-l
2. STUDY APPROACH II-3
2.1 Information Sources Used II-3
2.2 Interviews with EPA Regional and State RCRA Professionals . . . II-3
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TABLE OF CONTENTS (continued)
Page
3. NATURE AND EXTENT OF ECOLOGICAL RISKS II-5
3.1 Extent of Ecological Threats at RCRA Facilities II-5
3.2 Nature of Ecological Threats at RCRA Facilities II-5
3.3 Conclusions II-S
4. ECOLOGICAL RISK ASSESSMENT METHODS 11-10
4.1 Rulemaking Analyses 11-10
4.2 Site-Specific Analyses 11-12
4.3 Conclusions 11-14
5. RCRA ECOLOGICAL RISK MANAGEMENT ISSUES 11-17
5.1 Review of RIAs 11-17
5.2 Site-Specific Decisions 11-17
5.3 Conclusions 11-18
6. ECOLOGICAL RISK ASSESSMENT AND MANAGEMENT
NEEDS FOR THE RCRA PROGRAM 11-19
6.1 General Needs 11-19
6.2 Subtitle C Facility Permitting, Corrective Action, and
Closure Needs 11-20
6.3 Regulatory Analysis Needs 11-22
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OVERVIEW OF REPORT
This report summarizes a study conducted by the Office of Policy Analysis/Office of Policy,
Planning, and Evaluation (OPA/OPPE) of the U.S. Environmental Protection Agency (EPA)
concerning the nature and extent, assessment methods, and management issues relating to
ecological damages and risks at Superfund sites and RCRA facilities.7 More detailed reports,
which should be consulted for a complete description of the study, have also been prepared by
OP A. These reports are as follows:
"The Nature and Extent of Ecological Risks at Superfund Sites and
RCRA Facilities," EPA-230-03-89-043 (June 1989).
"Ecological Risk Assessment Methods: A Review and Evaluation of
Past Practices in the Superfund and RCRA Programs," EPA-230-03-89-
044 (June 1989).
"Ecological Risk Management in the Superfund and RCRA Programs,"
EPA-230-03-89-045 (June 1989).
This summary report is organized in two parts. Part I highlights the key OPA study
findings with regard to the Superfund program and discusses their overall implications. Part JJ
of this report describes the key findings and implications concerning the RCRA program.
Readers should refer to the three more detailed reports listed above for additional information
on the study methods and findings and for full reference lists (only key references are cited in
this summary report).
1 In this report, the term ecological "threat" is used to refer collectively to both observed
and predicted impacts. As used in this report, the term "damage" refers to observed impacts
only, and the term "risk" generally refers to predicted impacts.
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PART I: SUPERFUND
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1-1
1. INTRODUCTION
In developing and implementing programs under the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA, or Superfund), EPA has focused
primarily on analysis and mitigation of human health risks. In general, less emphasis has been
placed on analysis and mitigation of ecological threats at Superfund sites.
This program emphasis has resulted partly because of the general absence of
standardized EPA policy and guidance in the areas of ecological assessment methods and
ecological risk management under Superfund. As an initial step in investigating issues related
to ecological threats at Superfund sites, EPA's Office of Policy Analysis (OPA) has conducted a
study of three broad topics: (1) the nature and extent of ecological threats at Superfund sites;
(2) the ecological assessment methods that have been used in the Superfund program; and (3)
the extent to which ecological concerns have been used as a basis for decision making (i.e.,
ecological risk management) at Superfund sites.
This part of the summary report is organized into five main sections. In Section 2, the
study approach and key information sources upon which the analysis is based are briefly
described. Sections 3, 4, and 5 summarize results from the studies of the nature and extent of
ecological threats, ecological assessment methods, and ecological risk management issues in the
Superfund program, respectively. Finally, Section 6 discusses the implications of these results,
opportunities for program improvements, and needs for further study.
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1-2
2. STUDY APPROACH
As mentioned in the introduction to this part, the study was conducted by analyzing
three related topics: the nature and extent of ecological threats, ecological assessment methods,
and ecological management issues at Superfund sites. These topics were analyzed based on
information obtained from a telephone survey, personal interviews, and a review of Superfund
site documentation and other relevant reports.
A telephone survey was conducted to ask people in government agencies questions
related to ecological threats at Superfund sites. In particular, interviewees were asked to
identify sites with known or suspected ecological threats, describe methods used to assess those
threats, and describe how and to what extent ecological threat information has been used in
selecting Superfund site remedies. More than 50 people were called, including representatives
of EPA Headquarters and Regions, the Department of the Interior (DOI), the National
Oceanic and Atmospheric Administration (NOAA), and state Superfund offices. In some cases,
follow-up meetings were held with representatives from these organizations.
Several non-site-specific documents were reviewed for ecological threat information
related to Superfund sites. Particular references that were reviewed include:
a draft interim final version of the "Risk Assessment Guidance for
Superfund Environmental Evaluation Manual," being prepared
by EPA's Office of Solid Waste and Emergency Response
(OSWER);
draft "Guidance for Conducting Remedial Investigations and Feasibility Studies
Under CERCLA" prepared by the Office of Emergency and Remedial Response
(OERR);
OERR's draft "CERCLA Compliance With Other Laws Manual;"
"Interim Final Guidance on Preparing Superfund Decision Documents: The
Proposed Plan and Record of Decision" being prepared by OERR;
a report by EPA's Office of Policy, Planning and Evaluation (OPPE) entitled
"Unfinished Business: A Comparative Assessment of Environmental Problems;"
a critique of the Superfund program entitled "Right Train, Wrong Track: Failed
Leadership in the Superfund Program" by the Environmental Defense Fund and
others; and
a report entitled "Are We Cleaning Up? 10 Superfund Case Studies" prepared
by the Office of Technology Assessment.
Based on the telephone survey and review of written documentation, approximately 250
Superfund sites were identified as potentially posing some level of ecological threat. Of these
250 sites, site-specific reports were reviewed in detail for ecological threat information for a
sample of 52 sites. The 52-site sample was selected based primarily on the quantity and
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1-3
apparent quality of relevant documentation available for each site.2 The primary site-specific
reports reviewed were remedial investigations (RIs), feasibility studies (FSs), records of decision
(RODs), and ecological assessment reports, when available.
An unavoidable limitation in the approach is that almost all of the information obtained
and reviewed for the study pertains to National Priorities List (NPL) sites. Very few removal
and non-NPL sites were examined because limited documentation was available that describes
ecological issues at these kinds of sites.
2 Although all candidate sites were identified by at least one source as having known or
suspected ecological threats, most of the 250 sites had insufficient documentation to allow in-
depth review and thus were necessarily excluded from the smaller subsample.
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1-4
3. NATURE AND EXTENT OF ECOLOGICAL RISKS
Detailed results of the study characterizing ecological risks at Superfund sites are
presented in OPA's report entitled "The Nature and Extent of Ecological Risks at Superfund
Sites and RCRA Facilities," EPA-230-03-89-043, dated June 1989. This section summarizes key
findings from that report. Section 3.1 summarizes the nature of ecological threats at a sample
of 52 NPL sites; the extent of threats across this sample is summarized in Section 3.2. Section
3.3 describes how the ecological threats appear to be associated with certain factors and, in
Section 3.4, generalizations concerning the significance of these threats are discussed.
3.1 Nature of Threats at Superfund Sites
Exhibit 1-1 shows the general types of ecosystems affected and environmental media
contaminated at the 52 NPL sites examined. Based on the site documentation reviewed, almost
90 percent of the sites in this sample pose a threat to freshwater ecosystems. Threats to
terrestrial ecosystems have been observed or projected less frequently (at slightly less than 50
percent of the sites). This may be more a function of the extent to which terrestrial effects
were investigated at sites rather than a true indication of the frequency of these effects
(terrestrial effects generally were analyzed less rigorously than aquatic effects in the reports
reviewed).5 Soil, ground water, surface water, and surface water sediments were all frequently
observed to be contaminated at the sample sites.
Exhibit 1-2 identifies the biota that were observed or projected to be contaminated at
the sample sites, as well as the observed or projected effects caused by this contamination. As
shown, the biota most frequently observed to be contaminated are fish, vegetation, and aquatic
invertebrates; although few field monitoring data were reported, birds and mammals were
projected to be contaminated at a large portion of the sites. For example, fish or aquatic
invertebrates were observed to be contaminated at roughly 60 percent of the sites, while birds
or mammals were projected to be contaminated at approximately 70 percent of the sites. A
variety of toxic effects to aquatic fauna were observed at approximately 25 percent of the sites
and projected at another 45 percent. In addition, fish kills were reported at almost 8 percent
of the sites, bioaccumulation within the food chain was observed or projected at 54 percent of
the sites, and decreased species diversity was observed or projected at 21 percent of the sites.
When noted, adverse terrestrial effects usually took the form of damaged or killed vegetation,
loss of habitat, contamination or loss of food sources, and projected toxic effects to birds and
mammals.
3 In general, EPA has focused principally on the study of aquatic ecological damages and
risks, leading to the development of expertise, criteria, and policy in that area. Because of this
internal expertise, surface water problems may have received more consideration than possible
terrestrial impacts.
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1-7
3.2 Extent of Threats at Superfund Sites
The reports reviewed for this study contained limited quantitative information on the
extent of ecological threats, and most of the information that was available was limited to only
a few sites. In particular, quantitative estimates of ecological risk (i.e., predicted impacts) were
almost non-existent. Available information for the sample sites is summarized in Exhibit 1-3.
When available, information on both the areal extent and magnitude of contamination and
effects is provided.
The extent of threats varies widely across the sample, both in terms of the area affected
and magnitude of impact. Based on the site documentation reviewed, there are five sites
(approximately 10 percent of the sample) that appear to present relatively severe ecological
threats, characterized by high levels of environmental contamination spread over relatively large
areas with large populations of organisms that are (or could be) exposed. There is an equal
number that appears to present relatively minor threats, generally characterized by low levels of
environmental contamination confined to small areas and relatively small numbers of potential
ecological receptors. Therefore, based on the documentation reviewed, the majority (roughly 80
percent) of the sites can be categorized as relatively moderate in terms of ecological threats. It
is important to clarify that many of the sites grouped into this "moderate" category have
resulted in adverse effects and even death to some biota, or have caused environmental
contamination that is likely to cause adverse effects to biota. However, the threats at the
majority of these sites were categorized as moderate, for the purpose of relative ranking only,
mainly because: (1) the area affected generally appears to be small to moderate in size and the
biota affected generally appear to be limited to organisms close to the site; and/or (2)
contaminant levels appear to be below acutely toxic levels in most areas and the potential for
effects of chronic exposures at these sites is not well understood.
3.3 Analysis of Trends
Available data for the 52 sample sites suggest that a wide variety of waste types and
constituents are contributing to ecological threats at Superfund sites. As shown in Exhibit 1-4,
the most frequently occurring waste type in the sample (present at roughly a third of the sites)
is municipal/commercial/industrial waste commingled in a landfill, with the specific components
and sources of these wastes often being unknown. The relative high frequency of this waste
mixture illustrates the point that mixtures of several different chemicals, rather than just one or
two, are probably contributing to ecological threats at most sites. Exhibit 1-5 identifies the
principal contaminants observed at the 52 sample sites. The most frequently encountered
inorganics in the sample are lead, cadmium, arsenic, chromium, and zinc; the most frequently
encountered organics are volatile organic compounds (e.g., benzene, toluene, trichloroethylene),
PCBs, and polynuclear aromatic hydrocarbons (e.g., naphthalene, benzo(a)pyrene). Because of
limitations in the available site information, it was not possible to determine the substances
responsible for most of the ecological threats.
As shown in Exhibit 1-6, the most common types of waste management practices
resulting in releases at the 52 sites are landfills/dumps and surface impoundments, which
together account for roughly 80 percent of the sample. Of the sites with a landfill and/or
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EXHIBIT 1-3
EXTENT OF ECOLOGICAL IMPACTS IN THE 52-SITE SAMPLE
Category of Impact
Number Cumulative Areal
of Sites With Extent at Sites
Information on Extent a/ With Information
Contaminants/Magnitude b/
Surface Water Contamination
Contamination of Surface Water
Sediments
Soil Contamination
15
Fish Kills
209 stream
miles; and
3,954 acres
209 stream
miles; and
3,937 acres
2,240 acres
27 stream
miles
i Concentrations of 8 metals, PCBs, and
pentachlorophenol exceed AWQC 1.5 to 414,000 times.
i Observed contaminants include 7 metals, PCBs, and
asbestos.
i Concentrations frequently exceed background levels,
ranging from 15 to 820 times.
i Amounts of 4 metals and PCBs in sediments range from
10 pounds to 229 metric tons per site.
i Observed contaminants include 6 metals, asbestos, PCBs,
phenols, nitroaromatics, and other organics.
i Concentrations frequently exceed background levels,
ranging from 3 to 2,600 times.
i Volumes of contaminated soil range from 17,000 to
535,000 cubic yards per site.
i Severity of observed fish kills ranges from 100% to 10%
for affected areas.
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EXHIBIT 1-3 (continued)
EXTENT OF ECOLOGICAL IMPACTS IN THE 52-SITE SAMPLE
Number Cumulative Areal
of Sites With Extent at Sites
Category of Impact Information on Extent a/ With Information Contaminants/Magnitude b/
Defoliation 5 2,014 acres Observed contaminants include 3 metals and
pentachlorophenol.
Contamination/Degradation of 5 324 acres Observed contaminants include 2 metals, oils, and PCBs.
Wetlands/Marshes
Concentrations in sediments frequently exceed background
levels.
a/ Explicit information was provided on the areal extent or magnitude of contamination for 28 of the 52 sites in the sample; information from only those
28 sites is included in this exhibit.
b/ Indicates degree to which contaminant levels exceed criteria such as EPA's ambient water quality criteria (AWQC). Information on the exceedance of
criteria is not provided for soil and sediment contamination because generally applicable criteria for these media do not exist.
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1-12
EXHIBIT 1-6
FREQUENCY OF WASTE MANAGEMENT PRACTICES AND
ENVIRONMENTAL SETTINGS IN THE 52-SITE SAMPLE
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1-13
EXHIBIT 1-6 (continued)
FREQUENCY OF WASTE MANAGEMENT PRACTICES AND
ENVIRONMENTAL SETTINGS IN THE 52-SITE SAMPLE
FOOTNOTES
a/ While several of the sites employed more than one waste management practice, these
are the practices that were principally implicated as the sources of hazardous substance releases.
b/ Site environments were classified as generally rural if surrounding land uses are
described in reports as being predominantly agricultural, rural, residential, or light industrial in
combination with one or more of the preceding land uses. Site environments were classified as
generally urban if surrounding land uses were described as commercial and/or industrial.
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1-14
surface impoundment, the most commonly observed waste migration pathway affecting ecological
resources is seepage into ground water that in turn discharges to surface water (observed at
almost 65 percent of these sites). However, at most sites multiple release and migration
pathways from multiple sources were either observed or projected (e.g., runoff, erosion, direct
discharges).
In terms of environmental setting characteristics, the factor that appears to have the
greatest bearing on reported ecological threats is the proximity of the site to surface water (see
Exhibit 6). Almost 90 percent of the sites in the sample are either adjacent to or near
(generally within one or two miles) a surface water body, and roughly 60 percent are near a
wetland, swamp, or marsh. In addition, almost 40 percent of the sites were noted to have
surface water onsite, most commonly drainage ditches or small creeks that appear to act as
conduits for waste constituent migration, as well as habitat for aquatic receptors.
3.4 Generalizations Concerning the Significance of Threats
It is difficult to draw firm conclusions about the overall extent and significance of
ecological threats at Superfund sites because of: (1) major limitations in the available ecological
data (even for the 52 sample sites selected in part because they had the most information);
(2) a lack of ecological toxicity reference levels (i.e., "benchmarks") for many substances;
(3) scientific uncertainties about the response of ecosystems to chemical contamination; and
(4) a lack of Superfund policy on what constitutes a "significant" ecological threat.
Nevertheless, generalizations can be made concerning the following four aspects that relate to
the significance of ecological effects: the intensity of the effects, the duration of the effects,
the extent to which unique or particularly valuable resources are threatened, and the overall
context of the threats (i.e., whether they are local, regional, national, or global). Section 3.4.1
provides generalizations across the 52 sites studied in this project, and Section 3.4.2 discusses
generalizations across all Superfund sites.
3.4.1 Generalizations Across Sample of 52 Sites
The adverse ecological effects at Superfund sites can be very intense, including death to
aquatic and terrestrial organisms and complete devastation of habitat. Almost all of the sites in
the sample have contaminants present that are acutely toxic to aquatic organisms when present
in sufficient concentrations. In the sample studied, however, very intense (or acute) effects
were observed or projected at only a small fraction of the sites or appeared to be limited to
small areas. Most sites appear to present more of a long-term threat that to date has not
resulted in adverse effects that are easy to detect.
Based solely on the types of contaminants observed, it appears that ecological exposures
and adverse effects caused by contamination at the sample sites could persist for long periods of
time if no response action were taken. Most of the sites are contaminated with chemicals that
are persistent and bioaccumulative (e.g., PAHs, PCBs, lead, cadmium).
Ecological threats may be considered by some to be more significant if the resources at
risk are particularly valuable (i.e., unique, vulnerable, commercially significant, or recreationally
important). In that regard, Exhibit 1-7 identifies certain "sensitive or special" environments that
are or may be contaminated in the 52-site sample. Almost 60 percent of the sample sites
appear to be threatening wetland/marsh/swamp systems, and 25 percent may be threatening
endangered species or their habitats. In addition, roughly 10 percent of the sites are located in
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1-15
EXHIBIT 1-7
OBSERVED OR PROJECTED CONTAMINATION OF
SENSITIVE/SPECIAL ENVIRONMENTS IN THE 52-SITE SAMPLE
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Other
Environment Type
a/ This category includes state parks, lakes adjacent to parks, and nature study areas.
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1-16
or near wildlife refuges, and approximately 7 percent are possibly threatening aquatic habitat
noted in the site reports to be sensitive spawning areas for fish. The commercial resources that
appear to be at highest risk are fish and shellfish: approximately 17 percent of the sites noted
observed or projected threats to fish or shellfish that appear commercially significant. Very few
data are available on the recreational value of the resources potentially affected, except that
roughly seven percent of the sites may have contaminated areas likely to be used for
recreational purposes (e.g., state parks, lakes adjacent to parks, and nature study areas).
Virtually all of the sample sites individually pose ecological threats that are local in
nature. Only one site conceivably could cause adverse effects on a regional level. However,
the threats at individual sites must be considered along with the fact that there is a large
number of Superfund sites in order to assess the aggregate national extent of ecological threat.
3.4.2 Generalizations Across All Superfund Sites
The sample of 52 sites studied in this analysis may not be representative of all
Superfund sites, and it certainly was not a statistically based sample of the site universe.4 The
sample was drawn from a limited set of selectively identified sites, and probably is biased toward
sites with more obvious ecological threats (i.e., when compared to the universe of all sites, the
sample of 52 is likely to contain a larger fraction of sites with more obvious ecological threats
because they were recognized and investigated). The sample may also be biased toward sites
with more severe ecological threats, although that is less certain. Furthermore, the
representativeness of the sample results is uncertain given the fact that comprehensive efforts to
identify sites where ecological threats exist generally have not been made prior to this study.
For these reasons, statistically valid extrapolations of the sample results to the general
population of Superfund sites are not possible.
Simply for the purpose of illustration, however, the sample results can be generalized
over the entire Superfund site universe if it is assumed that the 52 sample sites examined here
are representative of sites having the potential for significant ecological threats. Using
information collected for this study, a very rough, preliminary estimate of the number of NPL
sites that have the potential for significant ecological impacts or risks would be between 220
and 420 sites (between approximately 18 percent and 35 percent of all sites either on or
proposed for the NPL).5 Furthermore, there is little reason to believe that non-NPL sites pose
less of an ecological threat than NPL sites. Therefore, if it is assumed that the estimated
percentage of NPL sites potentially posing significant ecological threats is valid for the 15,000
or so sites currently listed in CERCLIS as candidates for further investigation (i.e., roughly
16,000 of the 31,000 sites in CERCLIS will not undergo further investigation because they have
been categorized as "no further response action planned"), the total number of Superfund sites
with the potential for significant ecological threats would be between 2,700 and 5,300. The
total number of sites currently exhibiting relatively severe ecological effects is probably much
smaller.
4 At this time, a retrospective analysis of a statistically drawn sample would have limited
value because of severe ecological data limitations for the sites.
5 See OPA's report on the nature and extent of ecological risks at Superfund sites and
RCRA facilities (EPA-230-03-S9-043) for complete details on these illustrative numerical
generalizations.
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1-17
If it is assumed that the 52 sample sites examined here are representative of sites having
the potential for significant ecological threats, the characterization of ecological threats at the
sample sites would illustrate the nature of threats that may occur at all Superfund sites having
the potential for significant ecological threats. In order to make quantitative projections about
the extent of ecological threats across all Superfund sites, one would have to further assume
that: (1) the subset of 28 sample sites for which data are available on the extent of threats is
also representative; (2) available data on the extent of ecological threats are complete and
accurate; and (3) the above estimates of the total number of sites with the potential for
significant ecological threats are accurate. If these assumptions are valid and if the results for
the 52 sites are extrapolated over the upper bound of 5,300 sites with the potential for
significant threats, the total national extent of ecological impacts caused by Superfund sites
would include surface water contamination in as many as 12,000 stream miles, up to 8,000
stream miles of contamination of surface water sediments, as many as 64,000 acres of soil
contamination, fish kills in up to 1,700 stream miles, defoliation over 22,000 acres, and
contamination of up to 22,000 acres of wetlands and marshes (see detailed report on the nature
and extent of ecological risks at Superfund sites for more specifics on the derivation of these
numbers).
To help put these estimates in perspective, Keup (1985)6 estimates that there are
approximately 3,250,000 total stream miles in the U.S. The rough estimates given above for
surface water and surface water sediment contamination caused by Superfund sites are less than
0.5 percent of the nation's stream miles. According to EPA (1987),7 it is suspected that severe
contamination of sediments with toxicants released from all sources might exist in perhaps 1
percent of the nation's stream miles (not counting possible sediment contamination in the
nation's lakes, estuaries, or marine areas). The estimate given above for fish kills caused by
Superfund sites is less than 0.1 percent of the nation's stream miles. For comparison, EPA and
the Fish and Wildlife Service (1984)s have estimated that fish kills caused by all sources have
occurred in 15 percent of the nation's stream miles and that toxic substances from all sources
have adversely affected fish in roughly 10 percent of the nation's stream miles (not counting
fish kills or toxic substance contamination that may have occurred in estuaries, coastal waters,
wetlands, or the Great Lakes). Moreover, the rough estimate given above for the number of
acres of wetlands and marshes contaminated by Superfund sites represents less than 0.03
percent of the nation's total inventory of wetlands in the 1970's in the 48 conterminous United
States.9 Roughly 20 times more wetlands are lost each year as a result of all other stresses/0
with agriculture and development alone resulting in an annual loss of roughly 10 times more
6 Keup, 1985, "Flowing Water Resources," Water Resources Bulletin, American Water
Resources Association, Vol. 21, No. 2, April.
7 EPA, 1987, "Unfinished Business: A Comparative Assessment of Environmental Problems
- Appendix III," Ecological Risk Work Group, February.
8 EPA and Fish and Wildlife Service, 1984, "1982 National Fisheries Survey Volume I
Technical Report: Initial Findings," FWS/OBS-84-06.
9 Fish and Wildlife Service, 1983, "Status and Trends of Wetlands and Deepwater Habitats
in the Conterminous United States, 1950's to 1970's," April.
10
Ibid.
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1-18
wetlands than predicted to be contaminated by Superfund sites.77 Assuming these estimates are
valid, therefore, the relative contribution of Superfund sites to the nation's ecological impacts
appears moderate to small. This conclusion generally is supported by other EPA studies.72
Clearly, these numerical extrapolations are highly uncertain; they are provided only to
illustrate the possible extent of the problem, and as a quantitative point of departure to be
refined in future studies.
77 EPA, Office of Solid Waste, 1988, "Final Regulatory Impact Assessment/Background
Information Document - Wetlands."
72 EPA, 1987, "Unfinished Business: A Comparative Assessment of Environmental
Problems - Appendix III," Ecological Risk Work Group, February.
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1-19
4. ECOLOGICAL RISK ASSESSMENT METHODS
OPA's report reviewing ecological assessment methods in OSWER is titled "Ecological
Risk Assessment Methods: A Review and Evaluation of Past Practices in the Superfund and
RCRA Programs," EPA-230-03-89-044 (June 1989). That report focuses on major approaches
that have been used for characterizing impacts and risks rather than on a detailed analysis of
specific elements of these approaches. Each major methodological approach is evaluated in
terms of the ecological assumptions inherent in the approach, the types of ecological impacts it
can and cannot characterize, its main limitations, and its utility for risk management. In
addition, assessment approaches are analyzed in terms of the relative level of effort required
versus the type and quality of information yielded by that effort. This section summarizes key
findings related to Superfund sites from the detailed methods review report.
In general, the methods used to characterize ecological impacts at Superfund sites can
be divided into three broad categories: (1) screening-level methods for (a) determining the
overall nature and extent of ecological impacts associated with a number of diverse problem
areas, including Superfund sites, and (b) establishing remedial priorities at hazardous waste sites;
(2) methods for characterizing actual ecological impacts (i.e., those that have been measured or
observed) resulting from the release of chemicals at specific sites; and (3) methods for
characterizing potential ecological impacts (i.e., those that have not been measured or observed,
but are predicted) that might result from the release of chemicals at specific sites. Actual
impacts have been distinguished from potential impacts because the methods and data used to
characterize the two types of impacts differ markedly. Characterization of actual impacts
requires some type of survey or sampling of the condition of ecological receptors at and near a
site. Characterization of potential impacts is more predictive hi nature and requires information
on chemical hazard, exposure potential, and exposure-response relationships for the ecological
receptors. These three categories of methods are described and evaluated briefly in the
following subsections.
4.1 Screening-Level Analyses
Two types of screening-level analyses have included, or are being used at, Superfund
sites: analyses for establishing policy and regulatory priorities, and the Hazard Ranking System
(HRS). Each of these types of analyses is described and evaluated briefly in a following
subsection.
4.1.1 Analyses for Establishing Policy and Regulatory Priorities
Description. The purpose of these screening-level analyses is to provide a broad
overview of the nature and extent of ecological impacts associated with diverse problem areas,
different types of facilities, or various waste management practices. The primary type of priority
analysis that included Superfund sites is a comparative risk study.
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1-20
Three EPA comparative risk studies that were reviewed75 included a screening-level
evaluation of ecological threats posed by Superfund sites. In these studies, the relative
ecological impacts associated with diverse problem areas, including Superfund sites, were
assessed and ranked. Information on exposure levels and/or potential, types and societal value
of ecological receptors, hazards of constituents to receptors, and the areal extent and
reversibility of potential impacts was combined using professional judgment to derive a semi-
quantitative relative risk ranking for each problem area.
Evaluation. Comparative risk estimation can provide a nationwide overview of the
ecological hazards and/or impacts associated with Superfund sites relative to other problem
areas being analyzed. Comparative risk estimation cannot be used to establish remedial
priorities within the Superfund program itself. Such priorities are established with the HRS
(see section 4.1.2). The ranking procedure can be based on potential impacts, potential impacts
and likelihood of exposure, and/or actual impacts resulting from known levels of exposure.
Information on known impacts provides a better evaluation of the current extent of ecological
problems, while information on potential impacts provides a better evaluation of the extent of
possible future ecological problems (or uninvestigated current problems). Comparative risk
estimation does not provide new information about ecological impacts or quantitative estimates
of ecological risks.
4.1.2 Analyses for Establishing Superfund Remedial Priorities
Description. The Superfund program uses the HRS as a screening-level device for
establishing remedial priorities at hazardous waste sites. The HRS score is used to determine
whether a site is placed on the National Priorities List (NPL) and thus eligible for Superfund-
financed remediation. The HRS is a scoring system that evaluates factors (e.g., toxicity of
substances, number and type of potential receptors) that are indicators of the risks to human
health or the environment associated with a given site.
Evaluation. An evaluation of the HRS was beyond the scope of this project. Both the
current HRS and the proposed revisions to the HRS (53 FR 51962, December 23, 1988)
consider ecological risks to a specified list of "sensitive environments," but in both models
human health risks are weighted more heavily than ecological risks. Under the current HRS, a
site cannot be listed on the NPL solely on the basis of ecological concerns, although such
concerns can contribute to NPL listing. The final form of the revised HRS will not be
available until early 1990. Although it will expand the consideration of ecological concerns, the
extent to which this will affect NPL listing cannot be determined at present.
4.2 Approaches for Characterizing Actual Impacts
Description. At the 52 Superfund sites reviewed in this study, three main approaches
were used to characterize actual ecological impacts: evaluation of biotic community structure,
analysis of the morphological and/or physiological condition of individual organisms, and
13 EPA/OSWER, draft report, "Ecological Risk Characterization Methodology" (April
1988); EPA/OPPE, final report, "Unfinished Business: A Comparative Assessment of
Environmental Problems" (February 1987); and ICF Incorporated, draft report, "Regional and
State Comparative Risk Project: Approaches for Ranking Based on Ecological Risk/Impact"
(December 1987).
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1-21
comparison of measured contaminant concentrations to ecological benchmark levels^4 (see
Exhibit 1-8).
In the first approach, biotic community structure was compared in ecosystems exposed to
site contaminants and in nearby reference ecosystems. Measures of community structure
included species diversity or evenness indices, the presence of "indicator" species associated with
stressed ecosystems, a qualitative description of the community, and stressed or absent
vegetation. The techniques used most commonly to evaluate community structure were
systematic, quantitative field sampling or qualitative surveys, although aerial photography was
used at a few sites. Evaluations of this type focused on four major taxonomic groups or
organisms: terrestrial plants, vertebrates (e.g., fish, mammals, birds), benthic macroinvertebrates,
and shellfish.
A second approach used to characterize actual impacts was to compare the physiological
and/or morphological condition of individual organisms inhabiting the exposed ecosystem to
those in a reference area. The most common technique for making this comparison, used at
nearly all sites, was to collect organisms directly from the exposed ecosystem and from the
reference ecosystem and to examine the collected specimens. The most common endpoint used
to evaluate the condition of these specimens was tissue residue levels of contaminants, although
strictly speaking, elevated tissue residue levels do not indicate the presence of adverse biological
effects unless coupled with independent evidence of such effects. At some sites, additional
evaluation using histopathology or necropsy was conducted to measure the incidence of tumors,
lesions, developmental abnormalities, and other morphological or physiological symptoms of
stress. Evaluations focused generally on the taxonomic groups most likely to be exposed to site
contaminants.
A third approach for characterizing actual impacts was to compare measured
concentrations of contaminants in environmental media to ecological benchmark levels to
determine whether contaminant concentrations had reached a level likely to result in adverse
ecological effects. This approach was used most commonly for aquatic or wetland ecosystems,
and usually no specific organisms or endpoints of concern were identified.
Evaluation. Exhibit 1-9 provides a summary evaluation of the main approaches and
techniques used to characterize actual ecological impacts at Superfund sites. A qualitative
survey of biotic community structure can detect large, readily apparent impacts to exposed
ecosystems, including the presence or absence of indicator species. It also can be used to
determine the areal extent of such impacts. However, community-level impacts that are more
difficult to observe and impacts to populations or individual organisms generally will not be
detected with this approach. Severity of impacts is difficult to determine with this technique
unless it is extreme.
A quantitative measure of biotic community structure can detect less noticeable
alterations in community structure. Hence, sites at which community-level impacts are not
readily apparent might be identified with this approach. This approach also can provide a
numerical measure of the severity of impacts, although it is difficult to evaluate the ecological
14 Although comparing measured contaminant concentrations to ecological benchmarks is
not a valid measure of actual ecological impacts, it was used as a surrogate measure of actual
impacts at 17 of the Superfund sites reviewed.
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EXHIBIT 1-8
APPROACHES, TECHNIQUES, AND ENDPOINTS USED TO
CHARACTERIZE ACTUAL IMPACTS AT SUPERFUND SITES
Approaches
Techniques
Endpoints
Evaluation of Biotic
Community Structure
Evaluation of Individual
Morphology or Physiology
Comparison of Contaminant
Concentrations to Ecological
Benchmarks a/
Quantitative Sampling
Qualitative Surveys
Aerial Photography
- Field Sampling
- Histopathology, Necropsy
- Records of Mortality
- Detailed Field Studies
- Field Sampling
Diversity Indices
Indicator Species
Description of Community
Absent/Stressed Vegetation
Tissue Residue Levels
Disease/Abnormalities
Reproduction
Contaminated Media
Hazard Quotients
a/ Although this approach does not establish the existence of actual ecological impacts, it was used as
a surrogate measure of actual impacts at 17 of the sites examined.
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EXHIBIT 1-9
SUMMARY EVALUATION OF APPROACHES AND TECHNIQUES USED TO CHARACTERIZE ACTUAL IMPACTS AT SUPERFUND SITES
Approach or Technique Information Provided by
This Approach or Technique
Information Not Provided by
This Approach or Technique
Information Gained by Adding
This Approach or Technique
Evaluation of Biotic Community Structure
Qualitative Surveys
Identification of large,
readily apparent impacts
Areal extent of impacts
Identification of subtle
impacts
Impacts to individuals
or populations
Severity of impacts
(unless extreme)
Identification of sites with major
impacts to biotic communities
Quantitative Measures
Quantification of small,
subtle impacts
Severity of impacts
Areal extent of impacts
Impacts to individuals
or populations
Identification of sites with minor
impacts to biotic communities
Evaluation of Individual Morphology or Physiology
Examination of Specimens Direct evidence of injury
to individual organisms
Areal extent or magnitude
of impacts
Impacts to populations,
communities or the ecosystem
Identification of sites with major
impacts to individual organisms
-------
EXHIBIT 1-9 (continued)
SUMMARY EVALUATION OF APPROACHES AND TECHNIQUES USED TO CHARACTERIZE ACTUAL IMPACTS AT SUPERFUND SITES
Approach or Technique Information Provided by
This Approach or Technique
Information Not Provided by
This Approach or Technique
Information Gained by Adding
This Approach or Technique
Comparison of Measured Contaminant Concentrations to Ecological Benchmarks
Field Sampling
Nature and areal extent of
contamination/contamination
above benchmarks
Direct evidence of actual
impacts
Identification of exposure
pathways
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1-25
significance of a particular change in a community diversity or evenness index. Areal extent of
impacts can be determined by field sampling or, in some situations, by use of aerial
photography. The quality of information provided by quantitative measures of community
structure depends considerably on the scope and intensity of the sampling effort. Moreover,
the effectiveness of quantitative measures of community structure in characterizing actual
impacts depends largely on how well the ecological significance of any observed change in
community structure can be documented. For most quantitative metrics, there is no scientific
consensus on what constitutes an ecologically significant change, and a change considered
significant for one ecosystem might not be considered so for another.
Evaluation of the morphological or physiological condition of individual organisms
provides direct evidence of whether or not actual impacts have occurred in the organisms of
concern, and sufficient sampling can delineate the areal extent or magnitude (e.g., number of
individuals or size of population affected) of such impacts. Impacts can be evaluated with a
variety of techniques; the appropriate technique(s) for a given site will be determined to a large
extent by the particular contaminants present at the site. Use of this approach can identify
sites at which impacts to individual organisms have occurred even when community structure is
not affected significantly (or the ecological significance of any observed change in community
structure cannot be determined).
Evaluation of the morphological or physiological condition of individual organisms and
evaluation of community structure represent two different and somewhat complementary
approaches for characterizing actual impacts. Evaluation of community structure provides little
information about individual organisms within that community. Similarly, evaluation of the
morphological or physiological condition of individual organisms provides little information about
communities within the ecosystem. If there is little reason to expect one type of effect more
than the other at a given site, use of both approaches together will identify sites at which
effects on one or the other level might be overlooked. Neither of the above approaches
characterizes impacts to biotic populations. Relatively intensive field studies generally are
required for most population-level measures (e.g., density, age structure, survivorship,
reproductive rate). Historical records of fish kills were used as evidence of population-level
impacts at four Superfund sites, but no field population studies were conducted at the sites
reviewed.
Comparison of measured media contamination levels to ecological benchmarks is not a
valid approach for characterizing actual impacts. Evidence of concentrations of contaminants
above benchmark levels confirms the presence of an exposure pathway and the likely magnitude
of exposure but does not establish the existence of actual ecological impacts. Such evidence
might be considered a surrogate measure of actual impacts but is a more valid measure of
potential ecological impacts (see Section 4.3). At the sites where it was used as a surrogate for
actual impacts, this approach served mainly to document the nature and areal extent of
contamination.
4.3 Approaches for Characterizing Potential Impacts
Description. Four main approaches were used at the 52 Superfund sites reviewed in
this study to characterize potential ecological impacts: comparison of measured and/or
projected environmental concentrations of contaminants to ecological benchmark levels (i.e., the
quotient method), evaluation of potential impacts from estimates of exposure potential,
evaluation of potential impacts from estimates of hazard potential based on toxicity tests, and
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1-26
quantitative risk modeling (see Exhibit 1-10). In the first approach, measured and/or projected
concentrations of contaminants in environmental media or biota were compared to ecological
benchmark levels derived from toxicity studies on laboratory organisms. This approach was
applied most commonly to aquatic or wetland ecosystems. Ecological benchmarks used most
frequently were EPA's ambient water quality criteria (AWQC) and state water quality standards.
At some sites, additional benchmarks for contaminants in soil, sediments, or biota were derived
from chronic lowest-observed-effect levels (LOELs), chronic no-observed-effect levels (NOELs),
and acute LC50s or dietary LD50s.75 At most sites, the specific ecological endpoints being
assessed for potential impact were not identified in the documentation, although AWQC are
based on population-level effects. At sites where endpoints were specified, population-level
endpoints in vertebrates and invertebrates (e.g., excess mortality, depressed reproduction) were
the endpoints selected most frequently.
A second approach used to characterize potential ecological impacts consisted of a
quantitative or qualitative estimate of exposure potential, a qualitative description of the types
of ecological receptors likely to be exposed, and a qualitative discussion of the types of impacts
that might occur in those receptors. This approach was applied most commonly to terrestrial
ecosystems and wetlands. In this approach, no ecological benchmark is used to determine an
exposure level of concern. At most sites, no specific ecological endpoints were identified in the
documentation. At sites where endpoints were specified, excess mortality and depressed
reproduction in birds, mammals, and plants were the endpoints selected most frequently.
A third approach for characterizing potential ecological impacts was to evaluate hazard
potential, as determined by toxicity tests (i.e., exposing organisms to contaminated media in situ
or in a controlled laboratory setting). At the sample sites, toxicity tests were conducted using
sediments, leachate, and/or surface water. Organisms used in the toxicity tests included fish,
shellfish, daphnids, and bacteria. Endpoints used were either at the population level (e.g.,excess
mortality, depressed reproduction) or at the individual level (e.g., tissue residue levels). At the
sites reviewed, this approach was used exclusively for aquatic ecosystems or the aquatic
components of wetlands, although it also is applicable to terrestrial ecosystems.
A final approach used to characterize potential impacts (used only at one sample site)
was a mathematical model to evaluate the likelihood of a significant impact to the ecosystem
(i.e., catastrophic failure of fish reproduction) using an assumed food web, exposure/intake
assumptions, bioconcentration factors, and exposure/response information.
Evaluation. Exhibit I-11 provides a summary evaluation of the approaches used to
characterize potential ecological impacts at Superfund sites. Comparison of measured and/or
projected environmental concentrations of contaminants to ecological benchmarks provides
dichotomous (yes/no) information on whether adverse ecological impacts are likely. This
approach provides little information about the severity of effects if benchmark concentrations
are exceeded, although higher ratios in general will be correlated with more severe impacts.
This approach also provides little information on the effects resulting from exposure of biotic
receptors to multiple contaminants. Numerous specific techniques can be followed within this
general approach, and each provides different types of information. Evaluating measured
contaminant concentrations in environmental media provides information about potential
impacts resulting from exposures via direct contact with such media. Modeling contaminant
15
The concentration (LC50) or dietary dose (LD50) lethal to half the exposed organisms.
-------
EXHIBIT MO
APPROACHES, TECHNIQUES, AND ENDPOINTS USED TO
CHARACTERIZE POTENTIAL IMPACTS AT SUPERFUND SITES
Approaches
Techniques
Endpoints
Comparison of Measured and/or
Projected Contaminant Concentra-
tions to Ecological Benchmarks
Estimate of Exposure
Potential (No Benchmarks)
Measured Concentrations
Projected Concentrations
Measured Concentrations
Projected Concentrations
Qualitative Evaluation
Mortality
Reproduction
Growth
Community Structure
Mortality
Reproduction
Growth
Community Structure
Estimate of Hazard Potential
(Media Toxicity Tests)
Laboratory Toxicity Tests
In situ Toxicity Tests
Mortality
Reproduction
Growth
Tissue Residue Levels
Quantitative Risk Modeling
- Fault-Tree Analysis a/
Fish Reproductive
Failure
a/ The specific model used was not described in detail in the available documents.
-------
EXHIBIT Ml
SUMMARY EVALUATION OF APPROACHES USED TO CHARACTERIZE POTENTIAL IMPACTS AT SUPERFUND SITES
Approach
Information Provided by
This Approach
Information Not Provided by
This Approach
Information Gained by
Adding This Approach
Comparison of Measured and/or
Projected Contaminant Concen-
trations to Ecological Benchmarks
Yes/no information as to
whether impacts are likely
Impacts resulting from direct
exposures to contaminated media
and indirect exposures via food
chains
Quantitative measure of
severity of impacts if
benchmarks are exceeded
Impacts to communities or
the ecosystem (unless bench-
marks specifically account
for these)
Ecologically based cleanup criteria for
single contaminants
Estimate of Exposure
Potential
Estimate of Hazard Potential
(Media Toxicity Tests)
Types of ecosystems and
receptors potentially
exposed to contaminants
Quantification of likelihood
and severity of impacts to
exposed populations of test
organims
Identification of hazards
to site-specific populations
Areal extent of impacts
(if media tested at suffi-
cient number of locations)
Likelihood or severity
of potential impacts
Impacts to communities or
the ecosystem
Identification of sites with potential
ecological impacts
Identification of potential
exposure pathways
Ecologically based cleanup criteria for
mixtures of contaminants
Ecologically based cleanup criteria for
contaminants in soils and sediments
-------
EXHIBIT Ml (continued)
SUMMARY EVALUATION OF APPROACHES USED TO CHARACTERIZE POTENTIAL IMPACTS AT SUPERFUND SITES
Approach
Information Provided by
This Approach
Information Not Provided by
This Approach
Information Gained by
Adding This Approach
Quantitative Risk
Modeling
Likelihood of specific impacts
to individual organisms,
populations, communities, or
the ecosystem
Severity of impacts
Areal extent of impacts
not known3'
Quantification of ecological risks for
risk management decisions
to
- The specific model used was not described in detail in the available documents.
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1-30
concentrations at various trophic levels in a food chain provides information about impacts
resulting from indirect exposures. Evaluations of this type could be limited to substances with
widely accepted ecological criteria (e.g., AWQC), or they could include additional substances
with site-specific benchmarks derived from other toxicity data. Also, evaluations of this type
could consider each substance singly, or could incorporate hazard indices to evaluate potential
effects from exposure to multiple chemicals. As more of the above techniques are incorporated
into an evaluation, the likelihood of detecting potential ecological impacts at a site will increase.
A qualitative evaluation of exposure potential provides information on the types of
ecosystems and organisms that might be exposed to site contaminants and the possible types of
impacts that might result, but it does not provide any information on the likelihood, severity, or
ecological significance of such impacts.
Toxicity tests of environmental media provide information on the likelihood and severity
of particular adverse effects to populations of test organisms exposed to site contaminants. The
results from toxicity tests also can be used to evaluate hazards to site-specific organisms if the
test organisms are valid surrogates (e.g., they are particularly sensitive to site-specific
contaminants). Toxicity tests are particularly useful for identifying hazardous conditions at sites
with complex mixtures of chemicals and at sites where contaminants are present in media for
which no widely accepted benchmarks exist (e.g., soils, sediments). In principle, toxicity tests
can indicate the relative severity of potential impacts. For example, the dilution at which an
aquatic sample is lethal to 50 percent of the test organisms is an inverse measure of relative
severity. Such information can be used to identify levels of concern for toxicity test results, as
has been done for the NPDES permitting program (see Section 5.3). At the Superfund sites
reviewed, levels of concern for toxicity test results were not identified.
Use of toxicity tests is an approach that is complementary to comparison of
environmental concentrations of contaminants to ecological benchmarks, because the two
approaches identify different aspects of potential ecological impact. The former approach
evaluates the bioavailability of and hazards associated with particular mixtures of substances at a
site, while the latter approach evaluates the potential impacts associated with specific
contaminants of concern. Hence, use of both approaches at a particular site will increase the
likelihood of identifying potential ecological impacts. At present, comparison of environmental
concentrations of contaminants to ecological benchmarks can aid directly in the selection of a
mitigative remedy because most remedies are chemical-concentration specific (e.g., removal of
all soil with concentrations of PCBs above 50 ppm). In principle, toxicty tests also can be used
to select a mitigative remedy (e.g., removal of all soil toxic to more than 10 percent of the test
organisms), but in practice a prohibitively large number of toxicity tests might be required (e.g.,
to define the three-dimensional boundaries of the area to be remediated).
Quantitative risk modeling provides a specific probabilistic prediction of the likelihood of
a particular adverse effect in a given ecosystem. At present, there are few if any widely
accepted ecosystem risk assessment models. It might be possible to develop generalized models
for certain contamination scenarios so that only minor adaptations of the model to site-specific
conditions would be required. In most cases, however, it probably would be necessary to
develop models on a site-specific basis, an expensive and time-consuming effort. However,
quantitative risk modeling probably is the only way to quantitatively evaluate risks to a specific
element of an ecosystem (e.g., a commercial fishery) that is of concern at a particular site.
Numerous widely accepted release, transport, and fate models are available at present and could
be applied to a variety of terrestrial and aquatic systems to quantify exposure, chemical
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1-31
persistence, and other key risk assessment elements. These models, if incorporated into a tiered
and integrated modeling/data collection and analysis process, could provide more accurate risk
estimates in a resource-efficient manner. Exposure models were used at some of the sites
reviewed, primarily to estimate chemical concentrations in specific media and biota.
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5. SUPERFUND ECOLOGICAL RISK MANAGEMENT ISSUES
This section summarizes OPA's report entitled "Ecological Risk Management in the
Superfund and RCRA Programs," EPA-230-03-89-045 (June 1989). Section 5.1 identifies when
and describes how ecological risks are considered in the Superfund program, focusing primarily
on the remedial response part of the program. In Section 5.2, ecological risk management in
the context of the Regional biological technical assistance groups is briefly described. Finally,
Section 5.3 discusses several issues and problems that might impede effective ecological risk
management under Superfund.
5.1 When and How Ecological Risks Are Considered
Ecological risk management occurs principally at two points in the Superfund remedial
response process. The first is the determination of whether to place sites on the National
Priorities List (NPL), and the second is in the development and selection of remedies for
individual sites during the remedial investigation/feasibility study (RI/FS).
In most cases, the decision to place a site on the NPL is based on its Hazard Ranking
System (HRS) score. The inclusion of ecological factors hi the current HRS is limited;
ecological hazard is scored simply in terms of the distance from a site to the nearest "sensitive
environment." Under the current HRS scoring algorithm, NPL listing is impossible for sites
where ecological risks are the sole concern. Obviously, sites that score just below the NPL
listing threshold based on human health concerns can be pushed past the threshold based on
ecological concerns, but ecological risk is not the driving factor. Because Superfund remedial
action is less likely to occur at a site if it is not listed on the NPL, this is a crucial decision
point in the Superfund program, and one in which ecological risk is not an important
consideration. The proposed revisions to the HRS (53 Fed. Reg. 51962, December 23, 1988)
would expand the consideration of ecological concerns, but at this time it is uncertain to what
extent the revisions will affect site placement on the NPL.
The selection of a remedial action for a Superfund site is the most important ecological
risk management event for sites that have been placed on the NPL. To determine the extent
to which ecological concerns influenced remedy selection in the past, 20 records of decision
(RODs; Superfund program documents that explain the remedy selection decision for specific
sites) for sites exhibiting potential ecological problems were reviewed. Based on information in
the RODs, ecological concerns did not significantly affect remedy selection at almost half of
these sites. However, Agency representatives familiar with ongoing activities at Superfund sites
indicate that ecological threats are being considered in remedy selection more frequently now
than in the past. Based on the review of RODs and conversations with Superfund program
officials, ecological risk information is being incorporated into remedial site decision making in
several different ways, including those listed below.
Ecological toxicity testing and field surveys have been used in
conjunction with chemical testing (e.g., sampling and analysis of
sediments) as a basis for determining the need for remedial action,
or for identifying the portions of a site that require cleanup. For
example, at the Vineland Chemical site in New Jersey, a benthic
survey was used to determine which areas of a contaminated
stream showed evidence of ecological impacts and therefore
required remediation. Toxicity testing on sediment samples was
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1-33
used to correlate effects in the benthic population with laboratory-
controlled studies on benthic invertebrates. A similar approach is
being used as a basis for delineating the portion of the site
requiring remediation at Clear Creek, Colorado.
Performance goals, or target cleanup levels, for remedial actions
have been set at concentrations intended to be protective of
ecological receptors. For example, at the Marathon Battery site
in New York, a site-specific remediation level of cadmium in
marsh sediments was selected to protect against the threat to the
environment. At the Outboard Marine site in Illinois, the
selected remedial action involves the cleanup of sediments to a
level designed to ensure that water column concentrations of
PCBs would not exceed the chronic AWQC.
Effluent standards for ground-water treatment system effluents
have been set at ecologically protective levels. For example, at
the Geiger site in South Carolina, ground-water cleanup levels
were driven by ecological considerations, and effluent limits for a
ground-water treatment system are to be based in part on
bioassays.
Ecological considerations have led to the elimination of remedial
alternatives judged to have unacceptable ecological impacts. For
example, at the Mowbray site in Alabama, onsite encapsulation of
contaminated soils was rejected as a remedial action because it
would limit the ability of the site to be revegetated. Similarly,
stabilization/solidification of contaminated soils was rejected
because it would result in "permanent loss of wetland resources in
areas where soils are solidified."
At some sites, a remedial action has been selected even though site managers know that
it will not comply with ecologically based applicable or relevant and appropriate requirements
(ARARs). This has been justified in some cases based on the fund balancing provision of the
National Contingency Plan (NCP) (40 CFR 300.68(i)(l)). This provision allows EPA to choose
a remedy that does not meet ARARs when the need for ARARs compliance is outweighed by
the need for action at other sites, given the total amount of Superfund resources. For example,
the selected remedy at the Iron Mountain Mine in Redding, California, is capping the mine to
reduce infiltration of clean water, diverting runon, and assessing the feasibility of using concrete
to reduce acid drainage. This remedy will not reduce metals in adjacent surface water to levels
below the AWQC, nor will it necessarily protect the winter run of an endangered species of
salmon. A more expensive remedial alternative (removal of waste rock, tailings piles, and
sediments) that could have met ARARs was rejected as too costly ($1.4 billion) under the fund
balancing provision of the NCP.
Ecological concerns have also entered the remedy selection process in a number of
other ways, such as the imposition of requirements to continue environmental monitoring after
a remedial action to assure ecological protection, the selection of remedial actions to protect
recreational uses of natural resources, and decisions to defer remedial actions until more
detailed ecological data are available. Additional site-specific examples of how ecological
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concerns are being considered at Superfund sites are provided in OPA's detailed report on
ecological risk management.
5.2 Biological Technical Assistance Groups
In some EPA Regions, biological technical assistance groups have been formed to assist
Superfund remedial project managers in making sure that site response actions fully consider
ecological concerns. EPA Region 3 has had such a group for approximately four years, a group
has been operating for longer than a year in Region 2, and groups have been formed in
Regions 1, 4, and 10. Regions 5, 6, and 9 are well along in developing biological technical
assistance groups, and Region 8 is beginning to address how a group will be utilized if it were
organized. These groups have been supported through the Emergency Response Division and
the Hazardous Site Evaluation Division for over two years.
The biological technical assistance groups serve four main functions: (1) provide a
forum for communication; (2) identify ecological concerns; (3) determine data needs; and (4)
make recommendations. To help ensure effective communication, the groups consist of officials
not only from EPA, but also from other agencies that are natural resource trustees under
Superfund (e.g., the Department of the Interior, the National Oceanic and Atmospheric
Administration, states). The types of ecological concerns identified by the group include any
natural resources that may be affected by the site, the contaminants of ecological concern, and
the pathways by which contaminants may migrate to ecological receptors. The data needs
identified by the groups usually pertain to the extent and character of contamination in specific
areas, media, and pathways. Group recommendations to site managers consist primarily of
instructions to use particular ecological endpoints and assessment methods to satisfy data needs.
These recommendations often are phrased in terms of suggested monitoring activities, sampling
plans, and other analytical techniques. Recommendations also can identify ARARs, as well as
some of the beneficial and detrimental aspects of possible remedial alternatives.
The growing use of biological technical assistance groups in EPA Regional offices has
improved the consideration of ecological problems at NPL sites and should bring even more
improvement in the future. However, such groups do not exist in all Regions and, in the
Regions where biological technical assistance groups do exist, the useful guidance provided from
these groups still suffers from limits on available resources, personnel, and standards.
5.3 Ecological Risk Management Issues and Impediments
Important ecological risk management issues and impediments identified in this study are
briefly described below.
Limitations in Policy and Guidance. The most frequently cited cause for the lack of
effective ecological risk management is the absence of clear policy and guidance that articulate
the extent to which ecological data should be collected and used in the remedy selection
process. The absence of policy and guidance in many cases is due to a lack of appropriate
scientific knowledge and data, and additional fundamental research addressing these data gaps
clearly is needed. Although the difficulty of developing such policy and guidance in the face of
existing scientific uncertainties is widely recognized, some policy decisions could be reached
given current knowledge and data. For example, one of the most fundamental risk management
issues is the selection of appropriate biotic receptors and ecological effects to evaluate. There
is a virtually infinite number of combinations of receptors and effects that can be considered at
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a site. However, there currently is no policy or guidance for Superfund managers on which
receptors and endpoints should be assigned priority in terms of evaluating and minimizing
effects (e.g., Should impacts directly related to human health concerns or involving species with
economic value be given priority?). Given current ecological knowledge, it should be possible
to identify a set of receptors, endpoints, and levels of concern to be assigned priority at
Superfund sites. In addition, limited policy and guidance exists on how to interpret ecological
survey and toxicity test results/6 Therefore, even when extensive ecological assessments are
conducted, site managers have virtually no basis for judging the acceptability of ecological
damages and risks, or determining "how clean is clean." OSWER's "Risk Assessment Guidance
for Superfund -- Environmental Evaluation Manual" (Draft Interim Final, March 1989) should
supply useful guidance in these areas by providing an overview of topics to be considered, as
well as an excellent primer on ecology and ecological impacts. A recent memorandum (dated
December 29, 1988) from the Directors of OERR and the Office of Waste Programs
Enforcement to Regional Division Directors also provides a useful statement of policy
concerning the need to evaluate ecological issues in Superfund remedial actions and removals.
However, neither the recently published manual nor the policy statement provides complete
answers to the kinds of questions outlined above.
A Lack of Ecological Threat Criteria. Within the Superfund program, the only widely
used criteria for identifying and evaluating contaminant levels in the environment that are of
ecological concern are the AWQC. Unfortunately, chronic AWQC (which are often more
relevant to Superfund sites than acute criteria) or EPA-identified chronic LOELs (identified by
EPA when data are insufficient to support a chronic AWQC) are available for fewer than 40
percent of the substances found most frequently in high concentrations at Superfund sites.
Human health protection criteria are available for a larger number of substances; however,
these criteria often are not protective for ecological receptors. For example, approximately 50
percent of the drinking water maximum contaminant levels (MCLs) are higher than ecological
reference concentrations. Cleanup levels based on MCLs for these contaminants may not be
protective of aquatic life. In addition to this lack of criteria for evaluating threats to aquatic
organisms, even fewer criteria or toxicity data exist for evaluating potential impacts to terrestrial
organisms, and there are no widely accepted criteria for evaluating the significance of soil
contamination. Criteria for evaluating surface water sediment contamination also are very
sparse: EPA recently has developed a method for determining ecologically based sediment
criteria for organic compounds (and has developed interim criteria for 12 organic compounds),
but is just starting to develop a method for determining sediment criteria for heavy metals.
A Lack of Site-Specific Ecological Data. Partly because of the lack of policy and
criteria noted above, it appears that site managers often have insufficient ecological data for
their sites on which to make a sound decision. Information obtained from the review of
assessment methods (see Section 4) and from telephone interviewees indicates that ecological
assessments are often qualitative rather than quantitative, limited in scope, and not uniform
from site to site.
16 Guidance for denoting levels of concern for toxicity tests has been developed for the
NPDES permitting process. (See two EPA Office of Water reports; one entitled "Technical
Support Document for Water Quality-Based Toxics Control," September 1985, EPA-440/4-85-
032; the other titled "Permit Writer's Guide to Water Quality-Based Permitting for Toxic
Pollutants," July 1987, EPA-440/4-87-005.)
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A Lack of Resources. Because of the lack of funds and personnel committed to
ecological assessments, Superfund site managers are forced to set priorities for addressing
ecological concerns, both within and among sites. Priority-setting requires resolution of a host
of tradeoff issues. For example, when should ecological concerns be incorporated into cleanup
decisions, and what is the appropriate balance between the use of resources for protecting
human health versus the environment? In the process of ranking sites or selecting remedial
actions for specific sites, which ecological impacts should be given priority? What is the
appropriate decision process for choosing between the need for immediate cleanup at a site and
the need for thorough and time-consuming evaluation of ecological threats posed by a site?
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6. SUPERFUND PROGRAM IMPLICATIONS AND OPPORTUNITIES
Section 6.1 summarizes and discusses implications of the findings presented in Sections
3, 4, and 5. In Section 6.2, opportunities for further study and program improvements are
identified and briefly discussed.
6.1 Implications
Based on the information summarized in Section 3, one cannot conclude that ecological
threats at Superfund sites are negligible. Of the 52 sample sites examined in this study, virtually
all are contaminated with persistent and bioaccumulative chemicals that may present long-term
threats if not cleaned up; slightly more than half appear to be threatening unique, vulnerable,
commercially important, or recreationally important resources; and roughly 10 percent appear to
present locally severe ecological threats. Moreover, at most sites the extent and significance of
terrestrial effects, ecosystem-level effects, and effects of chronic exposures are not well
characterized. Considering the sites reviewed in this study, and the large number of all
Superfund sites estimated to have the potential for significant ecological threats, Superfund sites
collectively may present an important ecological problem that the Office of Solid Waste and
Emergency Response has responsibility and authority to control.
The ecological assessment methods identified in this review varied considerably among
sites in approach, level of effort, and how data were utilized, presented, and evaluated. This
variability appeared to result primarily from a lack of policy and guidance rather than a lack of
ecological expertise among Superfund professionals. In particular, there is limited or no
guidance for: selecting the appropriate contaminants, receptors, and ecological endpoints of
concern; choosing background values and/or reference sampling locations; selecting an
appropriate approach and level of effort for a given site; and interpreting survey and toxicity
test results. In addition, criteria for identifying and evaluating site contamination often are
lacking, and there is no general guidance on how to use available toxicity data in lieu of such
criteria. Without clear policy and guidance in key areas, evaluations of ecological threats will
continue to be inconsistent, may overlook significant ecological impacts or risks, and may not
provide information useful for the purpose of risk management decisions.
Given the limited ecological policy, guidance, and criteria available at the present time,
it appears that Superfund site managers are forced to make ecological risk management
decisions in the face of considerable uncertainty. At a minimum, this situation creates the
potential for decisions to be inconsistent among sites, a problem that may increase in
significance in the future due to the increased emphasis being placed on conducting ecological
assessments and the limitations in current Agency or program guidance on how to interpret the
findings from such investigations. The lack of sufficient policy and guidance also may result in
inadequate ecological management decisions, in the sense that opportunities for ecological
protection or enhancement may be lost or that ecologically detrimental remedies may be
selected. However, the most widespread effect of the lack of sufficient policy and guidance
appears to be a general absence of systematic, detailed consideration of ecological threats in
decisionmaking. In the current absence of clear policy and guidance, and in the remaining
Regions where biological technical assistance groups do not exist to provide support, decisions
to remedy environmental problems at a site sometimes have been criticized as reflecting the
manager's personal values and beliefs rather than EPA policy.
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6.2 Opportunities for Further Study and Program Improvements
If EPA determines that more systematic inclusion of information on ecological threats is
warranted for Superfund risk management decisions, moderate investment of resources in
developing policy and guidance, modifying and standardizing current approaches, and further
development of promising assessment methods will improve the consistency, accuracy, and
comprehensiveness of ecological assessments and ecological risk management at Superfund sites.
The paragraphs that follow identify and briefly describe a few opportunities for further study
and program improvements.
Develop Clear Directions for Including Ecological Risk Considerations in Superfund
Site-Specific Decision Making. OSWER's Risk Assessment Guidance for Superfund --
Environmental Evaluation Manual will help emphasize the role of ecological assessment in the
Superfund program. Similarly, a recent memorandum (dated December 29, 1988) from the
Directors of OERR and the Office of Waste Programs Enforcement to Regional Division
Directors provides a general policy statement on the need for effective environmental
evaluation in all Superfund remedial actions and removals. Neither the Environmental
Evaluation Manual nor the December 29 memorandum, however, provide clear guidance for
site managers on how to interpret and use results from ecological assessments. The proposed
revision to the National Contingency Plan provides fairly explicit guidance on remediation goals
to address human health risks, including ranges of "acceptable" risk, but it is vague in defining
protectiveness in terms of ecological threats (except for the directive to meet applicable or
relevant and appropriate requirements). Thus, specific guidance is needed for determining "how
clean is clean," and for determining when an ecological threat is "significant" and thus worthy of
a Superfund response. Although it may be difficult to define significant effects in quantitative
terms (e.g., number of acres contaminated, magnitude of exceedance of AWQC, number of
organisms potentially affected), qualitative criteria or factors to consider when judging
significance should be developed at a minimum. For example, the Council on Environmental
Quality's regulations for implementing the National Environmental Policy Act define
"significantly" in qualitative terms by discussing factors related to the context and intensity of an
effect (see 40 CFR §1508.27). Guidance in this area should clarify whether determinations of
the significance of ecological threats should be made on a program-wide or site-specific basis, or
both. Such guidance would be useful in implementing essentially all Superfund programs and
activities.
Assist in the Development of Ecological Protection Criteria and Advisories. There
currently are few ecological toxicity benchmarks to use in evaluating site contamination. For
example, EPA chronic AWQC are available for fewer than 20 percent of the substances found
most frequently in high concentrations at Superfund sites, making the characterization and
management of risks to aquatic organisms at these sites extremely difficult. In view of the need
for AWQC, but also in view of reduced budget allocations for the development of these
criteria, EPA's Office of Water Regulations and Standards (OWRS) initiated an Ambient Water
Quality Advisory (AWQA) program in 1986. The purpose of this program is to develop
AWQAs that are analogous to the chronic AWQC, but which are based on more limited
toxicity data and thus may be established more quickly. OSWER could assist OWRS in the
identification of substances that are of particular ecological concern at Superfund sites by
providing OWRS with a list of priority substances or groups of substances found most
frequently at high concentrations. The opportunity also exists for OSWER to support
development of generic risk-based benchmarks for ecological receptors, analogous to EPA's
reference doses used in the assessment of noncarcinogenic human health risks. Such ecological
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protection benchmarks could serve as Agency-approved, core values that could be adjusted as
needed to fit the needs of specific EPA programs. The development or expansion of ecological
benchmarks would be useful for the removal program, conducting pre-remedial activities,
selecting remedial actions, and implementing remedial actions.
Develop Guidance for Receptor Characterization. Characterization of actual and
potential ecological impacts at Superfund sites would be made more accurate, consistent, and
comprehensive by delineating a standard set of organisms and endpoints for evaluating threats
in particular ecosystems caused by particular substances. Along with this guidance, it would be
useful to develop a standard set of exposure/intake assumptions for the selected organisms,
guidance in interpreting the ecological significance of observed changes in the endpoints, and
clarification on whether the selection of appropriate receptors and endpoints should be based
on a program-wide or site-specific basis. Such guidance is particularly important to the remedial
action selection phase of the Superfund program.
Develop Guidance for Assessing Threats to Terrestrial Ecosystems. Threats to
terrestrial ecosystems also appear to be a high priority ecological problem in the Superfund
program, mainly because such a threat exists at many sites (virtually all of the sites reviewed in
this study have soil contamination) and because the exact nature and extent of terrestrial
impacts often are not well understood. There are currently no EPA criteria for the protection
of terrestrial life, although in some cases site-specific criteria have been developed on an ad hoc
basis. Although several factors will make it difficult to develop such criteria in the near future,
guidance for assessing terrestrial threats could facilitate protection in lieu of official criteria. In
particular, it would be useful to develop guidance for selecting terrestrial organisms and
endpoints to study and a standard set of exposure/intake assumptions for these organisms. A
compilation of information on critical parameters of physiology, metabolism, and natural history
for these species would facilitate quantitative estimates of exposures. It also would be useful to
develop guidance on methods to predict chronic no-effect levels in terrestrial organisms from
acute or chronic toxicity data for laboratory animals and agricultural crops. Such guidance
would be most useful for the remedial action evaluation and selection phase of the Superfund
program.
Establish Guidance for Addressing Contaminated Surface Water Sediments.
Contamination of surface water sediments appears to be a high priority ecological problem at
Superfund sites because such contamination: (1) exists at a large number of sites and is
sometimes spread over large areas, as evidenced in the 52-site sample analyzed for this study;
(2) may persist for extended periods; and (3) has the potential to affect commercially and/or
recreationally important species (i.e., shellfish and fish). Sediment contamination also presents
the problem of being difficult to remedy, as cleanup measures such as dredging may be equally
or more disruptive to aquatic ecosystems. EPA has recently developed a method for
determining ecologically based sediment criteria for organic compounds, and has developed
interim criteria for 12 organic compounds. However, EPA is just now starting to develop an
approach for determining ecologically based sediment criteria for heavy metals. Therefore,
there are very few widely accepted criteria for evaluating surface water sediment contamination,
no official guidance on how to use available AWQC or toxicity data for assessing sediment
contamination in lieu of widely accepted criteria, and no Superfund policy identifying
circumstances when it may be useful or necessary to remove contaminated sediments. Guidance
in this area is needed for implementing the removal program and essentially all phases of the
remedial program.
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Develop and Test An Ecological Threat Screening Model. Given the large number of
NPL and non-NPL sites that have the potential for significant ecological impacts, there appears
to be a real need for a rapid screening model separate from the HRS to identify and possibly
prioritize sites with the greatest potential for ecological impacts. An ecological threat screening
model also would be a useful tool for states to use in assessing and prioritizing Superfund sites
that are not eligible for federally funded response actions. Such a model could be intermediate
in detail and data input requirements between the HRS and the site screening model used by
the National Oceanic and Atmospheric Administration, and it could be designed exclusively to
evaluate ecological concerns. Once developed, an ecological threat screening model would be
most useful in the pre-remedial phase of the Superfund program.
Develop Guidance for Conducting and Implementing Toxicity Tests. Toxicity tests were
used at a number of Superfund sites to determine whether mixtures of contaminants in soils,
leachate, sediments, and the water column are potentially toxic to site-specific aquatic or
terrestrial organisms. Several standard toxicity test protocols exist, and others are under
development by EPA's laboratories. However, at no site reviewed was there a clear statement
as to what was considered a "significant" ecological hazard based on a media toxicity test result.
Characterizing ecological hazard based on media toxicity tests could be standardized by (1)
summarizing the types of media toxicity tests available, the species to which they can be applied,
the endpoints they measure, and the ecological significance of changes in those endpoints, and
(2) developing guidance for using toxicity test results to determine ecological benchmark levels,
and denoting levels of concern for each toxicity test. Such guidance has been developed for
the NPDES permitting process, and it could possibly be adopted directly by OSWER to
establish levels of concern and cleanup criteria for some aquatic ecosystems. Because media
toxicity tests are most likely to be conducted as part of the remedial program, guidance in this
area would be most useful for conducting pre-remedial activities, selecting remedial actions, and
implementing/completing remedial actions.
Establish a Formal Communications Network for Biological Technical Assistance Groups.
During discussions with personnel in EPA Region 3, the Region expressed an interest in
expanding the extent to which biological technical assistance groups and ecological experts in
other Regions share information, lessons learned, and experiences. EPA's Emergency Response
Team currently supports communications among biological technical assistance groups by, among
other activities, sponsoring a workshop to assist in the development of such groups and for
presentation of individual case studies. It would be useful to investigate the feasibility of a
formal communications network to complement these existing channels of communication and if
appropriate, an efficient and effective way to implement it. For example, it may be helpful to
compile and distribute a set of case studies of sites where certain assessment methods have
been used successfully in the past. This enhanced communication would be useful in
implementing all programs and activities under Superfund, but it would probably most facilitate
the remedial action selection process.
Investigate Mechanisms for Coordinating Ecological Evaluations in the Superfund and
RCRA Programs. With the growth of biological technical assistance groups and the recent (and
forthcoming) policy and guidance related to ecological assessments under Superfund, ecological
considerations are receiving increased attention within the Superfund program. There are
several areas of the RCRA program that also involve the evaluation of ecological issues, such
as the development of RCRA regulations, hazardous waste definition, permitting, and corrective
action (see Part II of this report for additional discussion of the RCRA program). In general,
it appears that ecological evaluations under RCRA are currently less formalized than under
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Superfund, and that certain programs under RCRA that involve the consideration of ecological
risk could benefit from increased coordination with the Superfund program. For example, the
RCRA corrective action program is just getting started, but eventually it will have to overcome
many of the same difficulties encountered in Superfund's program. EPA could identify the
potential difficulties that pertain to ecological analyses and provide a forum for the Superfund
experience to be conveyed to RCRA permit writers. EPA also could investigate the feasibility
of various policy or program implementation options to assure that ecological concerns are
being considered in a consistent manner across the Superfund and RCRA programs.
In conclusion, the extent to which ecological considerations are taken into account in
the Superfund program has increased significantly in the recent past, partly due to the
formation of regional biological technical assistance groups and the growing awareness of
ecological issues created by new EPA guidance and policy in this area. There are, however,
important areas for further program improvements to help assure that Superfund site responses
are appropriately protective of the environment as well as human health. The opportunities for
further study and program improvements listed above appear to be, based on the findings of
this study, areas of work that are needed and that would produce useful results.
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PART II: RCRA
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1. INTRODUCTION
This part of the report summarizes the U.S. Environmental Protection Agency/ Office of
Policy Analysis (EPA/OPA) assessment of the characterization and management of ecological
risks at facilities subject to the Resource Conservation and Recovery Act (RCRA). The OPA
ecological risk project was initiated to develop policy and guidance for ecological risk
assessment and management in RCRA. The goals of this project include:
improving ecological risk assessment and management in the
RCRA program,
improving the balance between human health and environmental
concerns in Agency decision-making,
encouraging consistency across programs,
developing capabilities to conduct efficient and cost-effective
ecological risk analyses tailored to program needs, and
improving understanding of ecosystem functions.
This summary is divided into six sections. First, this introduction contains an overview
of the four principal RCRA ecological risk issue areas examined during the course of the
project. Section 2 describes the sources of information used to develop the analyses. Sections
3, 4, and 5 present the conclusions reached during the examination of these issue areas with
regard to the nature and extent of ecological risks at RCRA facilities, the methods used to
evaluate ecological risk, and the management of ecological risk in the RCRA program,
respectively. Section 6 outlines ecological risk and management needs for the RCRA program.
Overview of the RCRA Ecological Risk Project
In response to increasing concern that EPA has focused insufficient attention on the
ecological threats posed at RCRA facilities, EPA undertook this project to enhance its
understanding of these ecological threats and to identify ecological risk assessment methods and
management issues. As part of the detailed reports cited at the beginning of this summary, the
Agency prepared separate analyses for each of three RCRA ecological risk issue areas:
Nature and Extent of Ecological Threats at RCRA Facilities --
This analysis provides a rough estimate of the extent of ecological
damage at RCRA facilities and describes examples of such
damage. The analysis focuses mainly on Subtitle C facilities, but
also discusses other practices subject to RCRA, such as municipal
and special waste facilities. Both predictive modeling to support
regulatory activity and site-specific ecological assessments of
RCRA facilities and activities were investigated in developing this
analysis.
RCRA Ecological Risk Assessment Methods ~ This analysis
summarizes and evaluates methods used to characterize ecological
impacts resulting from releases of hazardous constituents and
wastes at RCRA facilities. The analysis also assesses methods
used to evaluate ecological impacts addressed by rulemakings.
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RCRA Ecological Risk Management Issues -- This analysis
discusses the extent to which ecological concerns have been used
as a basis for decision making in the RCRA program. The
analysis focuses on both rulemaking and site-specific decisions.
These analyses are included as sections of the three reports cited in the overview section of this
summary.
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2. STUDY APPROACH
2.1 Information Sources Used
OPA directed its efforts toward gathering information from two primary sources. First,
OPA collected and reviewed program analysis and regulatory development documents discussing
ecological effects at RCRA facilities. Second, OPA contacted an extensive network of EPA
Regional and State RCRA professionals familiar with specific facilities to identify sites where
ecological threats had been characterized and used in the RCRA decision-making process.
OPA also collected and summarized documentation for facilities identified by these personnel.
2.2 Interviews with EPA Regional and State RCRA Professionals
OPA's interviews of 51 EPA Regional and State RCRA professionals provided
preliminary results about the nature and extent of site-specific ecological threats, ecological
impact assessment methods, and the use of ecological threat information in RCRA decision
making.
The EPA Regional and State professionals identified 52 RCRA
Subtitle C facilities with known, suspected, or potential ecological
damages. We were able to obtain documentation of the site
conditions and history for 16 of these 52 facilities.
Nearly 20 percent of the professionals responded to questions
concerning the use of ecological assessments in RCRA
investigations. The remaining interviewees were not sufficiently
familiar with the topic to offer their opinions. Those individuals
who did respond to the questions generally stated that ecological
threats at RCRA facilities are not commonly investigated or that
no standard methods exist to aid in the assessment of ecological
threats. Assessment methods mentioned by the professionals
included toxicity testing, observation of vegetative cover,
contaminant body burden, community structure, key species
biomonitoring, fish/shellfish kill observation, bioaccumulation, and
proximity of sensitive or endangered habitat.
In general, the interviewees stated that ecological threats at
RCRA facilities are given inadequate consideration. This
inadequacy was attributed to a lack of appropriate assessment
methods, a lack of guidance, the impression that ecological
concerns are "too big to deal with," program emphasis on human
health, and an inability to address terrestrial threats. Only one
interviewee suggested that current considerations of ecological
threats in RCRA were adequate.
The professionals identified a number of uses of ecological
information in RCRA decision making. Specific RCRA decisions
relying on ecological risk information, to a limited extent at least,
include Alternate Concentration Limit (ACL) determinations,
setting permit requirements (e.g., determining ground-water
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protection requirements on the basis of observed ecological body
burden data), determining appropriate cleanup levels, and siting
hazardous waste facilities. One interviewee stated that ecological
risk information had little or no role in RCRA decision making.
The primary barriers to using ecological information in RCRA
decision making include the infancy of the corrective action
program, program emphasis on human health, the lack of
ecological risk guidance for corrective action, the lack of support
for risk assessment, State restrictions for on-site investigations, and
the lack of resource commitment to ecological risk assessment.
The primary ecological risk assessment and management needs
identified by the interviewees included determining appropriate
protection levels, developing an understanding of and investigative
methods to assess terrestrial effects, providing guidance for
description of community structure and other ecological measures,
evaluating the effects of mixtures of contaminants in the
environment, and balancing program emphasis between protection
of human health and the environment.
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3. NATURE AND EXTENT OF ECOLOGICAL RISKS
The analysis of the nature and extent of ecological threats at RCRA facilities involved
an investigation of six RCRA program areas: Subtitle C, Municipal Subtitle D, Mining Waste,
Coal-Fired Utilities, Oil and Gas, and Smelting and Refining. OPA evaluated the extent of the
ecological threats at these facilities based on a variety of broad regulatory and policy analyses
conducted by the Office of Solid Waste and the EPA Regional Offices. OPA's examination of
the nature of these threats also included a review of various OSW studies, and was further
enhanced through the development and analysis of damage case studies developed for each
RCRA program area. Exhibit II-l illustrates the number and type of RCRA case studies that
OPA analyzed for this project.
3.1 Extent of Ecological Threats at RCRA Facilities
The extent of ecological threats at RCRA facilities has been generally described in
Regulatory Impact Analyses, Reports to Congress, Background Documents, and special reports
prepared by OSW and the Regions. Although few of these sources investigate the extent of
ecological impacts in great detail, they do provide some indication of the problem. For
example, hundreds of incidents of releases from Subtitle C and D land disposal facilities to soil,
ground water, surface water, and air have been identified during the last three years, and OSW
expects that cleanup of these media at thousands of RCRA Subtitle C TSDFs will be required.
Furthermore, roughly 11 million barrels of oil and gas drilling wastes are released annually from
over 9,000 spills. In addition, an estimated 26 percent of the active mining and 32 percent of
the coal-fired utility facilities are within 5 km of sensitive environmental areas. Seventy-eight
percent of the phosphate mines sampled were within 5 km of wetlands, and 60 percent of
mining waste management case studies reported effects on non-human biota. Although little is
presently known concerning the characteristics of ecological damage resulting from these
releases, waste management activities conducted under all of these RCRA program areas appear
to pose a substantial potential threat to the environment.
3.2 Nature of Ecological Threats at RCRA Facilities
The precise nature of the ecological threats at RCRA facilities is not well understood,
but OPA identified and analyzed a number of examples of observed and predicted ecological
damages at RCRA facilities. Exhibit n-2 presents a summary, prepared by OPA, of the
observed ecological threat characteristics of each RCRA program area in terms of the observed
ecological damages, waste management practices, environmental settings, and principal waste
types.
The severity of ecological threats depends on environmental setting (e.g., wetlands),
facility size (i.e., quantity of wastes released), toxicity characteristics of the constituents released,
and the nature of the release event itself (e.g., flooding or leaching to soil). The observed
ecological damages from these releases are both long- and short-term in nature, and include fish
kills, diseased benthic invertebrates or desecrated benthic habitats, chronic or behavioral effects
on aquatic and terrestrial plant and animal species, and reduced floral and faunal species
diversity. Other observed impacts include reduced productivity in wetland habitats and
increased contaminant body burdens in aquatic species. Concentrations in water and soil have
been observed to exceed water quality criteria or other measures of aquatic toxicity at a number
of sites, and sparse vegetation and contaminated soils are also reported at some facilities. In
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EXHIBIT H-l
RCRA CASE STUDIES EXAMINED BY OPA
Subtitle 0(1)
Mining (45)
Subtitle C(24)
Coal Utllltle* (5)
U
Smelting and
Refining (16)
J
OH and Gas (29)
a 16 of the 24 Subtitle C case studies were obtained through phone
interviews and meetings with personnel in Regions 3 and 4. These 16
facilities were screened from a total of 52 identified facilities that may
have been evaluated for ecological damage. The remaining 8 case studies are
derived from damage cases contained in Subtitle C Location Standards
Background Information Documents/RIAs.
b Obtained from an OSWER document, "Ecological Evaluation of a Municipal
Landfill in the Superfund Program," written by John Bascietto, OWPE (undated).
0 Selected from 68 damage cases presented in the SCS Summary of
Environmental Incidents. Selected sites have experienced contaminant releases
resulting in threats to terrestrial and aquatic plant and animal species.
d Selected from 61 damage cases presented in the Oil and Gas Report to
Congress. Selected sites contain documented evidence of ecological damage.
9 Obtained from 16 damage cases included in the Smelting and Refining
Report to Congress.
f Selected from 14 damage cases presented in the Coal Utilities Report to
Congress. Selected sites contain documented evidence of existing or potential
ecological damage.
-------
EXHIBIT II-2
OBSERVED ECOLOGICAL THREAT CHARACTERISTICS OF RCRA EROGBAH AREAS
Program Area
Subtitle C
Subtitle D
Mining
Oil and Gas
Coal-Fired
Utility
Smelting
and
Refining
Observed Ecological Damages
Mortality - fish and vegetation
kills
Decreased species richness and
diversity
Increased body burden of
toxicants
Decreased productivity
Altered life cycles
Habitat alteration
Impaired overall health and
fertility of freshwater and
estuarine fish and macro-
invertebrates
Potential for contamination to
all environmental media and
thus widespread effects to
terrestrial and aquatic species
Fish kills
Impairment and reduction in
bird, benthic and other aquatic
organisms population
Bioaccumulation in terrestrial
organisms
Chronic and acute damages
Fish kills, benthic
invertebrate population
reductions
Reduced fertility and growth in
aquatic species
Vegetation damage
Bioaccumulation
Alteration of community
structure
Fish kills
Eradication of bottom-dwelling
organisms and other aquatic and
terrestrial plant and animal
life
Chronic effects also likely
Chronic and acute damages to
aquatic organisms
Surface water contaminant
concentrations >400 times AWQC
Haste Management Practices
Landfills
Surface impoundments (unlined)
Container storage
Wastewater discharge
Haste piles
Uncontained disposal (e.g.,
dumping to surface waters) of
combustion fly ash
Storage in unlined landfills of
all municipal wastes
Tailings ponds
Waste storage piles
Haste hauling
Surface impoundment
Cyanide wash stored in drums
Drilling operations
Storage and disposal of
drilling wastes in faulty
surface impoundments
Injection or discharge of
process waters to ground
surface
Improper storage or mishandling
of waste sludges and fly ash
wastes
Illegal or improper dumping of
wastes
Failure of surface impoundments
On-site wastewater settling
ponds
Cryolite sludge lagoons
Storage and disposal of spent
potliners
Environmental Settings
Near surface waters
Wetlands
Special habitats (i.e.,
endangered and protected
species habitat, and wildlife
refuge)
Limited available data
13 percent of facilities in
100-year floodplain
6 percent in wetland areas
Hear surface waters
Near surface waters
Desert or tundra environment
Limited available data
Predominantly near surface
water bodies
Over 70 percent within 2,000
feet of surface water
Haste Types
Metals - Cr, As, Pb, Hg
Aromatic hydrocarbons
and substituted aromatic
compounds
Solvents
Other VOCs
Creosote
PCBs
Acids
Alkali
Pesticides
Particulates
BOD
Microbes
Heavy Metals
Pesticides
VOCs
PCDFs
PCDDs
Tailings, overburden,
leachate solution, and
mine water containing:
cyanide, arsenic,
copper, zinc, cadmium,
lead, cobalt, silver,
chromium, iron, TSS, pH
" Drilling muds,
production brines,
wastewater, and oil
field effluents and
fracturing fluids
containing: chlorides,
benzene, lead,
phenanthrene, barium,
arsenic, fluoride,
antimony
Fly ash wastes
containing heavy metals
(aluminum, arsenic,
barium, cadmium,
chromium, copper, lead,
mercury, selenium and
silicon)
Spent potliners,
cryolite slurries,
cryolite sludges, slags,
and process fluids
containing: zinc,
copper, cyanide, lead,
cadmium and fluoride
a
-------
II-8
addition, more specific measures of ecological impact, such as oyster mortality and impacts on
bird nesting behavior, are occasionally reported.
Ecological damage was most often caused by the improper disposal or storage of wastes
in unlined landfills or surface impoundments. Storage in waste piles and application of
wastewaters to the land have also been noted as significant sources of damage. Exhibit II-3
summarizes the predominant release/exposure pathways associated with Subtitle C damage cases.
Most ecological damage was characterized in aquatic ecosystems and included fish kills
and reduced community diversity and structure. It is not clear, however, whether most
ecological damage does actually occur in aquatic habitats, or is simply easier, and therefore
more common, to characterize impacts in this medium. Reported chronic terrestrial habitat
damage includes impaired health and fertility of plant and animal species. Exhibit II-4
illustrates the types of ecosystems most commonly threatened or damaged in the RCRA Subtitle
C case studies.
The contaminants associated with ecological damage include virtually all waste types
managed at RCRA facilities. For example, the heavy metal wastes found at large volume waste
facilities have been implicated in a number of damage cases.
3.3 Conclusions
Although this analysis of facility characteristics suggests some patterns concerning
practices, settings, and wastes that pose the most severe ecological threats, it is questionable
whether quantitative projections based on these results can be made for the RCRA facility
population as a whole. Such extrapolations are tenuous, mainly due to the limited nature of
the available data characterizing the RCRA facilities and the lack of representativeness (in a
statistical sense) of the sites examined. Sufficient data to characterize the nature and extent of
ecological impacts at RCRA facilities accurately are generally not available. Nonetheless,
perhaps the most significant conclusion to be drawn from this analysis is that the wide range of
hazardous and non-hazardous substances managed at RCRA facilities, the numerous release and
ecological exposure pathways, and the diverse nature of the observed ecological impacts indicate
that releases from these facilities have the potential to affect all environmental media and major
ecosystem types. Hence, releases in wetlands, floodplains, surface waters, or in ecologically vital
or sensitive habitats should be considered a potential source of ecological damage.
-------
EXHIBIT II-3
SUBTITLE C CASE STUDY RELEASE/
EXPOSURE PATHWAYS
EXHIBIT H-4
ECOLOGICAL SETTING OF SUBTITLE C
CASE STUDY FACILmES
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Release/Exposure Pathway
Ecological Setting
" Land disposal subsurface releases refers to leaching of wastes or constituents
from landfills, lagoons, pits, or ponds and subsequent migration to ecological receptors.
b Land disposal overland releases refers to runoff from landfills, lagoons, pits,
or ponds to ecological receptors.
c Direct discharge of wastes or wastewaters to ecosystems (usually surface
waters).
d Spills and land application refers to migration of spilled or land applied
wastes or constituents to ecological receptors.
e Other release/exposure pathways include volatilization and no release of
hazardous constituents.
-------
n-io
f'^
4. ECOLOGICAL RISK ASSESSMENT METHODS
OPA's review of ecological risk assessment methods focused on describing and
evaluating the broad approaches that have been used to characterize impacts at RCRA
facilities. OPA described and evaluated each major approach based on the types of ecological
impacts characterized, the success in measuring those impacts, the main limitations and
assumptions underlying the approach, and the types of information provided for risk
management. This section summarizes the assessment methods used in analyses supporting
RCRA rulemakings, as well as those methods used in characterizing specific RCRA facilities.
4.1 Rulemaking Analyses
EPA has relied on screening-level analyses of diverse problem areas, facility types, or
waste management practices for evaluating ecological impacts in RCRA policy and regulatory
studies. Screening level analyses include: (1) evaluation of the proximity of waste sites to
sensitive environments, (2) survey of damage case studies, (3) quantitative modeling of potential
impacts based on damage case studies, and (4) comparative risk estimation. Specific methods
utilizing a comparison of environmental concentrations of contaminants to ecological
benchmarks include: (1) computing a hazard index for multiple contaminants, and (2) modeling
ecosystem exposure-response. These six methods are summarized and evaluated in
Exhibit n-5.
In the first approach, the assessment consists of determining how many facilities are
located within, or in proximity to, environments that are ecologically critical or vulnerable, have
a particular cultural significance, or have been set aside for conservation. Information from
sources such as the Natural Heritage Program data base of sensitive or critical habitats is
typically used in these analyses. For example, the analysis of mining waste practices relied on
this approach.
Developing surveys of damage case studies involves identifying specific facilities where
damages have been noted, collecting and reviewing documentation for these facilities, and
combining the various damage case descriptions into one or more "typical" damage case
scenarios according to geographic area, specific waste types, affected media, and waste
management practices. Several RCRA analyses have relied on this case study approach,
including the Smelting and Refining and Oil and Gas Reports to Congress, and the Location
Standards Regulatory Impact Analysis (RIA).
The quantitative modeling used in support of rulemaking generally involves evaluating
potential ecological impacts that might result from "typical" damage case scenarios. In the
modeling approach used in the Draft Smelting and Refining Report to Congress reviewed by
OPA, EPA compared modeled concentrations of contaminants in receiving waters to ecological
benchmarks (i.e., ambient water quality criteria).
EPA has also used comparative risk estimation to rank the relative ecological impacts
associated with widely diverse facilities or problem areas. This approach derives a qualitative or
semi-quantitative relative risk ranking for each type of facility or problem area by assimilating
information on exposure levels and/or potential, types and societal value of ecological receptors,
hazards of constituents to receptors, and the areal extent and reversibility of potential impacts.
-------
EXHIBIT II-5
SUMMARY EVALUATION OF APPROACHES USED TO CHARACTERIZE POTENTIAL IMPACTS AT RCRA FACILITIES
Approach or Technique
Information Provided by
This Approach or Technique
Information Not Provided by
This Approach or Technique
Information Gained by Adding
This Approach or Technique
Qualitative Evaluation
of Exposure Potential
Contaminant Concentration
vs. Ecological Benchmark
Evaluation of Hazard
Potential (Media Toxicity
Tests)
Types of ecosystems and
receptors potentially
exposed to contaminants
Yes/no information as to
whether impacts are likely
Impacts resulting from direct
exposures to contaminated
media and indirect exposures
via food chains
Quantification of likelihood
and severity of impacts to
populations of test organisms
Identification of hazards to
site-specific populations
Areal extent of impacts (if
media tested at sufficient
number of locations)
Likelihood or severity
of potential impacts
Quantitative measure of
severity of impacts if
benchmarks are exceeded
Impacts to communities or
the ecosystem (unless
benchmarks specifically
account for these)
Impacts to communities or
the ecosystem
Identification of sites with
potential ecological impacts
Identification of potential
exposure pathways
Ecologically based cleanup criteria
for single contaminants
Ecologically based cleanup criteria
for mixtures of contaminants-/
Ecologically based cleanup criteria
for contaminants in soils and
sediments
4 NPDES permit guidelines (EPA/OW 1985, 1987) define bioassay-based cleanup criteria for some ecosystems.
-------
n-12
The Office of Solid Waste and Emergency Response and Regions I, El, and X have performed
such analyses.
4.2 Site-Specific Analyses
OPA's review of site-specific methodological approaches is based on a limited sample of
RCRA facilities. Only 16 RCRA facilities were documented by OPA as having undergone
ecological assessments beyond a screening level, and all of these facilities are regulated under
the Subtitle C program. Actual impacts were evaluated at nine of these 16 Subtitle C facilities,
and potential impacts were estimated at 11 facilities. The methods used for these RCRA
facilities are summarized below.
EPA has used three primary approaches to characterize actual ecological impacts at
specific RCRA facilities: (1) evaluation of biotic community structure, (2) analysis of the
morphological and/or physiological condition of individual organisms, and (3) comparison of
environmental concentrations of contaminants to ecological benchmark levels. These methods
were generally used in association with corrective action analyses. Exhibit EI-6 summarizes and
evaluates these methods.
Evaluations of biotic community structure have focused on species diversity indices for
benthic macroinvertebrates and fish in aquatic ecosystems and the absence of vegetation in
terrestrial ecosystems. Two major types of community structure evaluations include qualitative
surveys and quantitative measures. In general, qualitative surveys are low-effort techniques used
to document large, readily apparent changes in community structure, while quantitative
techniques (including indices of community structure and aerial photography) require more
detailed analyses offering greater ability to distinguish subtle impacts.
Analyses of the morphological and/or physiological condition of individual organisms
have concentrated on fish and shellfish in aquatic ecosystems and birds and plants in terrestrial
ecosystems. (Most of these analyses have focused on tissue residue levels, although, strictly
speaking, elevated tissue residue levels do not indicate the presence of adverse biological effects
unless coupled with independent evidence of such effects.) At one facility, investigators used
an histopathological examination to determine whether there was a greater incidence of
abnormalities in fish exposed to contaminants than in fish in a reference environment.
A final method used to characterize actual ecological impacts at RCRA sites involves
comparing environmental concentrations of contaminants to ecological benchmark levels derived
from toxicity tests on laboratory organisms. The purpose of this approach is to determine
whether contaminant concentrations have reached levels known to result in adverse effects in
the tested organisms. When the ecological benchmarks are designed to be protective of biota,
such as AWQC (the most frequently used ecological benchmarks), this comparison is a
surrogate measure of actual impacts. However, this approach serves mainly to document the
nature and extent of contamination at a site and does not establish the existence of actual
ecological impacts.
OPA has identified three main approaches used to characterize potential ecological
impacts at the RCRA facilities reviewed: (1) comparison of environmental concentrations of
contaminants to ecological benchmark levels, (2) qualitative evaluation of potential impacts from
-------
EXHIBIT II-6
SUMMARY EVALUATION OF APPROACHES AND TECHNIQUES USED TO CHARACTERIZE ACTUAL IMPACTS AT RCRA
FACILITIES
Approach or Technique
Information Provided by
This Approach or Technique
Information Not Provided by
This Approach or Technique
Information Gained by Adding
This Approach or Technique
Evaluation of Biotic Community Structure
Qualitative Survey
Identification of large,
readily-apparent impacts
Areal extent of impacts
Quantitative Measure
Quantification of small,
subtle impacts
Severity of impacts2/
Areal extent of impacts
Evaluation of Individual Morphology or Physiology
Examination of Specimens
Detailed Field Studies
Direct evidence of injury
to individual organisms
Areal extent or magnitude
of impacts
Quantification of small,
subtle impacts to
individuals or populations
Identification of subtle
impacts
Impacts to individuals or
or populations
Severity of impacts
(unless obvious)
Impacts to individuals
or populations
Impacts to populations,
communities or the ecosystem
Impacts to communities
or the ecosystem
Comparison of Contaminant Concentration to Ecological Benchmark
Field Sampling
Nature and areal extent of
contamination
Direct evidence of actual
impacts
Identification of sites with major
impacts to biotic communities
Identification of sites with minor
impacts to biotic communities
Identification of sites with major
impacts to individual organisms
Identification of sites with minor
impacts to individuals or
populations
Identification of exposure
pathways
^ The Ohio Environmental Protction Agency (Ohio EPA 1988) has developed guidelines that define severity of impacts for some ecosystems.
-------
11-14
estimates of exposure potential, and (3) qualitative evaluation of potential impacts from
estimates of hazard potential based on media bioassays. Exhibit II-7 summarizes and compares
these three approaches to characterizing potential impacts.
The first approach, also known as the quotient method, was used exclusively for aquatic
ecosystems. EPA's ambient water quality criteria were the most frequently-used ecological
benchmark; State standards and acute toxicity values (LC50s) also were used at some facilities.
EPA used qualitative evaluations of potential impacts for terrestrial ecosystems and the
terrestrial component of wetland ecosystems. These evaluations focused on acute mortality or
altered community structure resulting from estimated exposure potential for mammals, birds,
reptiles, and plants.
Investigators used media bioassays for fish, daphnids, and algae to evaluate hazards in a
freshwater and a wetland ecosystem. Specific hazards identified in the bioassays included acute
mortality and depressed reproduction.
43 Conclusions
The methods used to characterize ecological impacts identified in this review varied
considerably in approach, level of effort, and the manner of data utilization, presentation, and
evaluation. Exhibits II-8 and II-9 illustrate the types of ecological assessment methods used at
the 16 Subtitle C case study facilities to assess actual and potential ecological damages. The
variety of methods applied appears to result primarily from a lack of policy and guidance rather
than a lack of either appropriate methods or ecological expertise among the investigators.
Because there are no clear guidelines for conducting ecological assessments at RCRA facilities,
there is no established methodology for screening sites for potential ecological impacts and
assessing actual or potential impacts at particular sites. Moreover, there is no widely accepted
method for quantifying ecological risks at RCRA facilities for the purpose of risk management
decisions. Hence, an investment of resources to develop guidance, modify and standardize
current approaches, and further develop promising techniques and methods should improve the
consistency, accuracy, and comprehensiveness of ecological assessments at RCRA facilities. The
implications of OPA's findings about ecological assessment methods for the RCRA program are
discussed in Section 6 of this part of the report.
-------
EXHIBIT II-7
SUMMARY EVALUATION OF APPROACHES USED TO CHARACTERIZE ECOLOGICAL IMPACTS IN POLICY
AND REGULATORY STUDIES
Approach or Technique
Information Provided by
This Approach or Technique
Information Not Provided by
This Approach or Technique
Information Gained by Adding
This Approach or Technique
Screening-Level Analyses
Proximity of Waste Sites
to Sensitive Environments
Survey of Damage Case
Studies
Quantitative Modeling
Based on Damage Case
Studies
Comparative Risk
Estimation
Number of sites located in or in
close proximity to sensitive
environments
Types of impacts associated with
activities under review
Contaminants and settings
associated with impacts
Potential impacts associated with
activities under review
Types of contaminants and releases
associated with potential impacts
Estimate of relative ecological
risks/impacts associated with
problem areas under review
Types of impacts possible
Likelihood of impacts
Estimate of the extent of
actual impacts associated
with activities under review
Estimate of the extent of
potential ecological impacts
associated with activities
under review
New information about
ecological impacts
Quantitative estimates of
ecological risks
Screening-level identification of
types of sites with potential
for ecological impacts
Identification of types of facilities
and settings that have resulted in
the greatest amount of ecological
damage in the past or at present
Identification of types of facilities
that pose the greatest potential for
ecological impacts
Identification of problem areas that
pose the greatest (and least)
ecological risks
H
-------
EXHIBIT II-8
EXHIBIT H-9
METHODS USED TO ASSESS ACTUAL IMPACTS
AT RCRA FACILITIES
METHODS USED TO ASSESS POTENTIAL IMPACTS
AT RCRA FACILITIES
10
(A
0)
0>
(A
(0
O
"5 «
k.
0)
3 2
US
10
(A
0)
(0
(0
o
0)
.n
Blotlc Individual F'»ld
Community Morphology or Population
Structure Physiology StudU*
Other
W
H-1
ON
Contaminant Eitlmat* of Estlmit* of
Concentration* Hazard Potential Exposure
va. Ecological Potential
Benchmarks
Methods Used
Methods Used
-------
11-17
5. RCRA ECOLOGICAL RISK MANAGEMENT ISSUES
The Office of Policy Analysis investigated the use of ecological impact and risk
assessment information to support rulemaking activities and site-specific decision making. OPA
reviewed eight RIAs to assess the use of ecological information in the rulemaking process:
Subtitle D Criteria Revisions RIA;
Corrective Action RIA;
Land Disposal Restrictions for Solvent Wastes RIA;
Small Quantity Generator Rule RIA;
Location Standards RIAs (including floodplains and wetlands
background documents);
Smelting and Refining RIA;
Mining Waste RIA; and
Oil and Gas RIA.
Each of these RIAs was prepared within the last several years and, therefore, provides a good
indication of the type of information currently being collected and evaluated by OSW in the
RCRA rulemaking process. OPA also evaluated site-specific decision making in the RCRA
program in four broad areas: hazardous waste definition determinations, Subtitle C permitting,
Subpart F corrective action, and Subpart S corrective action. Documentation for specific
RCRA sites involved in one or more of these processes served as the basis for the analysis of
site-specific decision making. Based upon a review of this RIA and facility documentation,
OPA sought to determine how ecological risk information is currently being used to support
decisions in the RCRA program and to identify approaches for improving the use of such
impact information.
5.1 Review of RIAs
The RIAs indicate that most RCRA rulemakings are justified in terms of their benefits
to human health, rather than protection of the environment. This conclusion is supported by a
review of Federal Register notices for rulemakings from 1979 to the present, which indicates
that the threat of ecological damage is rarely used as the primary basis of support for rules
affecting RCRA facilities. Although some actions are based on a combination of ecological and
human health risks, they usually rely on human health risk assessments for any quantitative
determinations and discuss ecological benefits in a qualitative or descriptive fashion.
5.2 Site-Specific Decisions
With regard to site-specific decisions, OSW is engaged in a growing number of waste
definition, permitting, and corrective action decisions that may involve ecological impacts.
Under the hazardous waste definition process, ecological concerns are generally not
considered because the criteria for listing hazardous waste (at 40 CFR 261.11) focus exclusively
on physical and chemical waste characteristics and toxic effects to humans. However, the
criteria do provide an indirect means by which a waste can be listed for ecological concerns; a
waste can be listed if it contains any of the constituents in Appendix VIE, some of which are
included because they are toxic to environmental receptors. In practice, however, the listing
rationale for individual hazardous waste streams are virtually always based upon human health
endpoints.
-------
n-is
The extent to which ecological threats are addressed in permitting decisions depends
largely on the status of the facility seeking a permit. Under current permitting practices,
ecological information is not requested from the owner or operator of most facilities. Such
information is deemed unnecessary because the permitting standards are designed to ensure that
facilities do not release hazardous wastes or constituents to the environment, thereby protecting
surrounding ecosystems. Nonetheless, certain types of facilities do experience permitted releases
to the environment, such as air emissions from thermal treatment facilities or incinerators.
Ecological concerns are addressed consistently only when past releases or impacts are observed
at a facility seeking a permit or permit modification. The ecological evaluations performed at
such facilities, therefore, are generally for the purpose of evaluating the level of cleanup
required to address a past release, rather than the controls needed to prevent future damage.
Corrective action for releases of hazardous constituents at RCRA facilities is currently
addressed under Part 264, Subpart F. Corrective action under Subpart F is triggered when
constituent concentrations in ground water exceed background concentrations or MCLs. There
is little opportunity for any type of ecological (or human health) risk assessment or management
in this process. Ecological receptors are implicitly protected by requiring cleanup when
background levels are exceeded. The exception is for the handful of constituents with MCLs;
approximately 50 percent of the MCLs are higher than ecological reference concentrations and
thus may not be protective of aquatic life. In addition, however, the ACL process provides an
important regulatory tool within the RCRA program to implement ecological risk management.
Facility owner/operators may petition for ACLs for specific constituents. These ACLs would
then serve as the target level for cleanup of the constituent in ground water. The guidance
and regulations for the ACL process clearly require that ecological impacts, as well as human
health impacts, must be considered when setting ACLs. In fact, petitioners often base their
requested ACLs on ecological toxicity data for the constituents in question because
environmental exposures are more likely than human exposures in most facility settings.
Under HSWA, the Agency is developing a new approach to corrective action to address
hazardous constituent releases from all solid waste management units to all environmental
media. Under this new approach, implemented in the pending Subpart S corrective action
regulations, all RCRA Subtitle C facilities will undergo a RCRA Facility Assessment (RFA) to
identify past releases. If releases are discovered, the facility may undergo a RCRA Facility
Investigation (RFI) to characterize the release. If the impacts of the release are significant, the
owner/operator must conduct a Corrective Measures Study (CMS) to identify an appropriate
cleanup alternative.
5.3 Conclusions
OPA's analysis indicates that, in general1, ecological concerns have not played a
significant role in past regulatory development or site-specific decision making in the RCRA
program. RCRA program needs associated with incorporating ecological considerations in the
decision-making process are discussed in Section 6 of this part of the report.
-------
n-i9
6. ECOLOGICAL RISK ASSESSMENT AND MANAGEMENT NEEDS FOR THE RCRA
PROGRAM
This section outlines the various ecological risk assessment and management needs for
the RCRA program identified by OPA in the preceding analyses. OPA has identified policy,
guidance, methods, data, and training/expertise needs that apply to the RCRA program in
general as well as specific RCRA program areas. The general RCRA needs apply to all major
areas of the RCRA program, including corrective action activities and ACL petitions; Subtitle C
permitting activities; listing, delisting, and hazardous waste identification; special waste programs;
and regulatory analysis. Following the discussion of general needs, we present specific needs
for Subtitle C facility permitting, corrective action, and closure; regulatory analysis; hazardous
waste listing/delisting; special waste programs; and the Subtitle D program.
6.1 General Needs
Although the Agency is mandated under RCRA to protect human health and the
environment, it has not described the manner in which environmental impacts should be
identified and addressed. Resolution of four major policy and guidance issues would clarify the
role of ecological damage information in RCRA:
Identify the ecological endpoints of concern and levels of
ecological impact that warrant Agency action (i.e., the damage
level that constitutes a "significant effect");
Address the manner in which actions to minimize human and
ecological impacts should be balanced;
Provide direction on when ecological threats must be considered
and the appropriate scope and level of effort of ecological risk
analyses; and
Develop procedures for involving personnel from other agencies
or EPA Program Offices who possess specific ecological
assessment expertise in the RCRA ecological risk decision-making
process.
In light of the difficulties and importance of accurately determining the severity of
ecological impacts through evaluations of exposure levels and toxicity of specific constituents,
there is a need for the development of standard qualitative and quantitative methods for
measuring ecological damage. Five specific methods development needs are listed below:
« Create site screening methods to quickly and inexpensively gather
information on the areal extent and reversibility of ecological
damage at a site by using commonly available toxicity data and
benchmarks;
Develop methods for using and interpreting qualitative measures
of ecological damage resulting from releases of single and multiple
chemicals;
-------
H-20
Develop a standard set of organisms and endpoints for evaluating
impacts in particular ecosystems and for particular substances and
develop procedures for measuring and interpreting the ecological
significance of observed changes in these endpoints;
Develop methods for determining standard uptake/exposure levels
for different ecological receptors to hazardous substances in
different environments; and
Establish standard procedures for developing and applying acute and chronic
ambient water quality criteria for the protection of freshwater and marine life.
Due to the variety of ecological receptors, hazardous constituents, and environmental
settings that must be considered in ecological assessments, the data requirements to support
such assessments can be extensive. OPA has identified four primary ecological risk assessment
data needs:
Develop a queriable data base containing peer-reviewed ecological
toxicity data and information;
Adopt a list of ecological toxicity thresholds for key RCRA
constituents and for different species and environments;
Compile existing information and data bases describing habitat and
species information into a queriable data base; and
Communicate organism- and chemical-specific data needs to other
programs, offices, and agencies to focus research on chemicals and
organisms most useful to the RCRA program.
With regard to the training/expertise needs of the OSWER ecological risk assessment
and management program, OPA identified three basic needs:
Create bioassessment groups in Headquarters and Regions to
serve as nuclei for ecological assessment expertise;
Improve cooperation/integration with other State and Federal
Agencies and EPA Offices to gain access to ecological assessment
expertise; and
Institute training for current personnel and hire additional staff
trained in ecological assessment techniques.
In addition to these general RCRA program needs, more program-specific needs are
outlined below.
6.2 Subtitle C Facility Permitting, Corrective Action, and Closure Needs
Ecological risk considerations in RCRA Subtitle.C permitting, corrective action, and
closure can be improved by:
-------
H-21
Consistently gathering ecological impact data;
Setting constituent concentration action levels at thresholds that
are protective of human health and ecological receptors;
Relying on ecological assessment expertise early enough in the
decision-making process to characterize ecological threats
accurately; and
Developing approaches for expanding or modifying cleanups or
remedial actions to mitigate ecological (and human health)
impacts, and procedures for verifying this mitigation;
OPA has identified several needs for ecological risk management in the proposed
Subpart S corrective action program. Resolution of these major policy and/or guidance issues
would clarify the role of ecological threat information in Subpart S corrective action.
Policy and/or guidance for incorporating ecological risk
information when setting priorities for RFIs. Given the limited
resources available to the Regions and States and the large
number of sites with past releases that will require RFIs, the
Regions must set priorities. As a result, the Regions are
developing their own priority setting schemes.
Policy and/or guidance for collecting information appropriate for
ecological risk assessment during the RFI, when most of the
detailed information for use in decision making concerning
corrective action is collected. Only a handful of RFIs have been
completed at RCRA facilities, and it is therefore difficult to assess
the extent to which ecological concerns are addressed.
Policy and/or guidance for utilizing ecological risk information in
determining when corrective actions should be conducted. Under
the pending draft Subpart S rules, corrective action is triggered if
pollutant concentrations in air, water, and/or soil exceed action
levels that are identified for several constituents. These action
levels are based primarily on human health risk. Cleanup levels
are also based on human risk assessment. Damage to ecosystems
may serve as sufficient reason to trigger corrective action, but this
decision is left to the discretion of the permit writer.
Policy and/or guidance for considering ecological concerns in the
CMS. At present very few facilities have reached this point in
the process. As a result, it is difficult to assess the extent to
which ecological risk management will occur in the selection of
corrective measures.
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6.3 Regulatory Analysis Needs
The consideration of ecological concerns in RCRA rulemakings could be enhanced
through developing the following:
clear statements of policy requiring the analysis of ecological
impacts hi benefits and impacts assessments;
protocols for incorporating qualitative measures of ecological
impacts in rulemaking decisions;
guidance and methods for improving the quantitative measurement
of ecological impacts; and
clear identification of the threshold levels of ecological impacts
that warrant rulemaking action.
An important reason for the lack of rigorous ecological risk assessment to support
rulemaking decisions appears to be the absence of a resource commitment to develop methods
for quantifying and valuing ecological damages on the national level. Although EPA has
described the types of ecological impacts that occur at RCRA sites through case studies, this
largely descriptive information cannot readily be assimilated and weighed in the decision-making
process.
6.3.1 Hazardous Waste Listing and Delisting
The Listing program identifies wastes and waste constituents which are hazardous to
either human health or the environment. Any waste or waste constituent identified as
hazardous is subject to regulation under RCRA. RCRA listings apply to specific or non-
specific processes, or specific wastestreams. Individual wastestreams may vary, however,
depending on raw materials, industrial processes, and other factors. Thus, while a waste that is
described in 40 CFR §261.31, 261.32, and 261.33 generally is hazardous, a specific waste from
an individual facility meeting the listing description may not be. For this reason, 40 CFR
§260.20 and §260.22 provide an exclusion procedure, allowing persons to demonstrate that a
specific waste from a particular generating facility should not be regulated as a hazardous waste.
Delisting petitions are submitted to the Agency for evaluation in order to demonstrate whether
the wastestream or waste constituent meets the criteria of the RCRA listing.
The consideration of ecological risk in the RCRA listing and delisting programs can be
improved by the following:
Developing a policy requiring the consideration of ecological
toxicity data for constituents in the listing and delisting process;
Collecting data or information describing ecological damage from
management of the waste constituent during the listing process,
rather than simply focusing on human health damage;
Providing access to ecological assessment personnel during the listing process;
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Developing guidance to petitioners describing the type of
ecological impact data to be reported in delisting petitions;
Expanding the Vertical and Horizontal Spread (VHS) modeling
approach for evaluating delisting petitions to consider exposures
other than through the consumption of contaminated drinking
water;
Evaluating predicted downgradient wastestream concentrations
using ecological criteria, as well as human health criteria.
63.2 Special Wastes
Under RCRA, certain special or large volume wastes are specifically exempted from
Subtitle C management requirements. These wastes include mining, utility, and oil and gas
extraction residues. Because many of these special wastes are generated in rural areas,
ecological impacts at these sites may be a significant concern. However, because these sites are
not presently required to obtain operating permits under RCRA, data describing ecological
impacts at these sites are scarce.
Managing and assessing ecological risks at special waste sites could be improved by the
following:
Expanding ongoing programs to collect data characterizing the
ecological impacts at special waste sites to support policy and
rulemaking development;
Developing requirements mandating the submission of ecological
impact monitoring data by site owners and operators;
Determining ecological impact threshold levels for constituents
that are primarily found at special waste sites (e.g., chloride); and
Investigating the need for siting criteria or facility technical
standards to limit ecological degradation at special waste sites.
633 Subtitle D Waste Facilities
Program needs specific to the Subtitle D program, which can improve the analysis of
ecological risk, include the following:
Investigate or evaluate the potential applications of biological
standards, biological monitoring, or other innovative approaches at
Subtitle D facilities, in addition to ongoing ground-water and soil
monitoring activities;
Establish a data base to track ecological monitoring data for
Subtitle D facilities to support policy development and regulatory
activities;
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Review and, if necessary, develop ecological impact thresholds for
regulatory action for relevant constituents of concern at Subtitle
D facilities (e.g., BOD);
Investigate the need for additional or revised siting criteria or
facility technical standards to limit ecological degradation at
Subtitle D facilities.
In sum, the program needs OPA has described above represent activities that can
improve the collection and management of ecological impact and threat information in the
RCRA program.
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