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Site Remediation News
January 1997 (Vol 9 No 1) - Article 05

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Ecological Risk Assessment In NJDEP's Site Remediation Program: Conducting A Baseline Ecological Evaluation
By: Nancy Hamill, Research Scientist and
Edward Demarest, Ph.D., Research Scientist
Division of Publicly Funded Site Remediation
Hazardous Site Science Element
Bureau of Environmental Evaluation and Risk Assessment

Ecological evaluations and risk assessments are conducted at contaminated sites (1) to address actual impacts or the potential for adverse ecological effects resulting from site-related contamination, (2) to evaluate the effects of alternative remediation strategies, and (3) to establish clean-up levels for the selected remedy that protect ecological receptors.

Ecological risk assessments have been performed for National Priorities List (NPL) sites since the early 1990s pursuant to National Contingency Plan (NCP) requirements. With the passage of P.L. 1993, c.139 which includes the Industrial Site Recovery Act (ISRA) (N.J.S.A. 13:1K-6) and the Hazardous Site Remediation Act (N.J.S.A. 58:10B), ecosystem protection has been integrated with current Site Remediation Program (SRP) initiatives directed toward the protection of human health; together they form the basis of remedial decisions for all sites under its jurisdiction. P.L. 1993, c.139 established an "Environment Advisory Task Force" that will consist of scientists and others from industry, academia, public interest groups, and government. The Task Force is charged with making recommendations to the Department on the feasibility, development, and application of ecologically-based remediation standards. Until such recommendations are available, N.J.S.A. 58:10B directs that the Department shall determine the need for and application of remediation standards to protect the environment on a case-by-case basis in accordance with USEPA regulations and guidances. SRP's initiatives in ecological evaluation and risk assessment are coordinated through the Bureau of Evaluation and Risk Assessment (BEERA), Environmental Toxicology and Risk Assessment Section (ETRA).

A tiered approach for conducting of ecological evaluations and ecological risk assessments has been developed by the SRP. Tier I, the Baseline Ecological Evaluation (BEE), has proved to be an efficient and cost-effective screening process and is required for all SRP sites. A BEE assures that all sites are addressed for potential ecological effects early in the remedial process; sites without ecological concern are quickly eliminated from further, more rigorous site-specific investigation. Only those sites that present the potential for adverse ecological effects are retained for further investigation and/or risk assessment at the Tier II level. It is at the Tier II level that definitive estimates of risk and the basis for determining clean-up goals are provided.

While a BEE must be performed, evaluators are to use best professional judgment based on USEPA guidance. The purpose of this article is to provide further guidance on how to perform a BEE and to provide direction on the format and content of the final report delivered to the SRP.

The objective of the Baseline Ecological Evaluation is to examine the site for the co-occurrence of (1) contaminants of potential ecological concern, (2) environmentally sensitive areas, and (3) a chemical migration pathway to these sensitive areas. The intent is to use existing site documents, existing analytical data, and the results of a qualitative site visit to document these conditions in a brief report submitted as part of the Site Investigation (SI) report or as a stand-alone document if conducted outside of the SI. A work plan is not required for Tier I investigations. The BEE report should include, but is not limited to, the following information:

1. Contaminants of Potential Ecological Concern (COPEC)

Analytical data must be presented in a tabular format according to media and chemical fraction. Sample quantitative limits and data qualifiers should be included. If an adequate number of samples were taken and it is appropriate for the area of concern, the arithmetic mean, maximum concentration detected, 95 percent upper confidence limit, concentration range, and frequency of detection should be included. It is important to report measurement of parameters affecting toxicity to biota (e.g., total organic carbon, particle grain size, alkalinity, hardness) was well as standard field parameters (e.g., temperature, pH, dissolved oxygen). No potential COPEC should be excluded from consideration without proper justifica-tion pursuant to USEPA guidance. Maximum measured contaminant concentrations are to be compared to ecotoxicologically-based benchmarks, or screening values, using a "weight of evidence" approach. If the measured concentration exceeds the benchmark, further assessment may be warranted since the potential for adverse ecological effects is indicated. For contaminants typically considered to biomagnify, concentrations below the screening values do not necessarily negate the potential for adverse effects; these should be evaluated on a case-by-case basis. SRP currently recommends the media-specific screen-ing values from the following references:

a. Surface Water

  • New Jersey Surface Water Quality Standards, N.J.A.C.7:9B

  • Federal Ambient Water Quality Criteria for Acute/Chronic Aquatic Life Protection, 40 CFR Part 131

b. Sediment

  • "Guidelines for the protection and management of aquatic sediment quality in Ontario," Ontario Ministry of the Environment, ISBN 0-7729-9248-7, 1993, Persaud, D., R. Jaagumagi, and A. Hayton. (Fresh water sediments)

  • "Incidence of adverse biological effects within ranges of chemical concentrations in marine and estuarine sediments,&qyuot; Environmental Management 19:81-97, 1995, Long, E.R., D.D. MacDonald, S.I. Smith, and F.D. Calder. (Estuarine and marine sediments)

  • "Briefing Report to the EPA Science Advisory Board on the Equilibrium Partitioning Approach to Generate Sediment Quality Criteria," EPA 440/5-89-002.

c. Soil

The scientific literature and various ecotoxicological databases should be consulted. Suggested references include:

  • "Contaminant Hazard Reviews," Fish and Wildlife Service, U.S. Department of the Interior, various publication dates, Eisler, R.

  • "Toxicological Benchmarks for Wildlife: 1994," Oak Ridge National Laboratory, Oak Ridge, TN, Opresko, D.M., B.E. Sample, and G.W. Suter.

  • "Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Terrestrial Plants: 1994 Revision," Oak Ridge National Laboratory, Oak Ridge, TN, Will, M.E., and G.W. Suter.

Note that all benchmark values are intended to be used for screening purposes only and must not be considered as regulatory criteria or site-specific cleanup numbers. Any screening values used should be presented alongside analytical summary data in tabular format.

2. Environmentally Sensitive Areas

Environmentally sensitive areas are thoroughly described in N.J.A.C. 7:1E-4.10. If present on-site, adjacent to the site, or under the influence of the site in any manner, these areas should be briefly described in the BEE report. Included should be a qualitative description of land use and major ecological habitat types, including natural and manmade areas (e.g., forested wetland, old field, waste lagoons, wildlife refuge). A map indicating sensitive area boundaries and an estimation of area covered by these habitat types, etc., should be provided. More comprehensive habitat and wildlife (plant and animal) surveys are usually reserved for the Tier II process.

3. Contaminant Migration Pathways to Environmentally Sensitive Areas

The potential for contaminants to migrate from the source to receptors must be evaluated during a site visit and documented in the BEE report. The text should include a description of potential chemical migration pathways. For example, surface impoundments may affect a receptor via direct exposure, they may contaminate groundwater that then discharges to a surface water body, and they may contaminate surrounding soil or surface water bodies via overflow and overland transport. It is appropriate to include a qualitative comparison of contaminants in various media with known site-related contamination.

A "Results and Discussion" section should summarize and interpret findings of the evaluation and present a reasonable decision regarding the need for further studies, based on technical information and best professional judgment. For example, a slight exceedance of a conservative screening value for one compound in one media would likely not warrant further investigation.

In summary, the BEE is a streamlined evaluation conducted with limited data using conservative assumptions for parameters where site-specific data are lacking. While the results of the BEE may overestimate actual risk, a "no further action" decision can be supported without additional investigation. If the results of the BEE indicate the realistic potential for ecological risk at the site, the appropriate conclusion will be that further site-specific investigation is needed at the Tier II level, which must be conducted in strict accordance with USEPA guidance ("Risk Assessment Guidance for Superfund, Volume II, Environmental Evaluation Manual," EPA/540/1-89/001, and the associated supplementary guidance "Ecological Update Series"). For further information, please contact the Bureau of Environmental Evaluation and Risk Assessment, Environmental Toxicology and Risk Assessment Unit, at 609/633-1348.

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Last revision: 2 Sept 97