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SURVEY OF METHODOLOGIES FOR DEVELOPING MEDIA SCREENING VALUES FOR ECOLOGICAL RISK ASSESSMENT
Citation:
Barron, M. AND S. Wharton. SURVEY OF METHODOLOGIES FOR DEVELOPING MEDIA SCREENING VALUES FOR ECOLOGICAL RISK ASSESSMENT. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY (1(4)):320-332, (2005).
Impact/Purpose:
To summarize methodologies of fourteen compilations of screening values commonly used by ecological risk assessors
Description:
Barron, Mace G. and Steve Wharton. Submitted. Survey of Methodologies for Developing Media Screening Values for Ecological Risk Assessment. Environ. Toxicol. Chem. 44 p. (ERL,GB 1200).
Concurrent with the increase in the number of ecological risk assessments over the past decade has been a proliferation of published compilations of ecological screening values (SVs) and the methodologies used in their derivation. This review summarizes methodologies of fourteen SV compilations that have been commonly used by ecological risk assessors to develop media-specific screening values. The reviewed SV methodologies included compilations from the States of Oregon, Texas, and New York, national program and regional offices of the U.S.Environmental Protection Agency (USEPA), the National Oceanographic and Atmospheric Administration, Oak Ridge National Laboratory (ORNL), Canada, the Netherlands, and Australia. Surface water SVs were primarily derived for the protection of aquatic organisms using two general approaches: (1) a statistical assessment of toxicity values by species groupings such as Ambient Water Quality Criteria, or (2) extrapolation of lowest observed adverse effect level determined from limited toxicity data using an uncertainty factor. Surface water SVs in several compilations were also based on toxicity to wildlife from drinking water exposure or chemical accumulation in aquatic prey. Sediment SVs were primarily derived for the protection of benthic invertebrates using two general approaches: (1) statistical interpretations of databases on the incidence of biological effects and chemical concentrations in sediment or (2) equilibrium partitioning derived values based on the surface water SV. Sediment SVs in only a few compilations were also based on toxicity to wildlife from chemical accumulation in aquatic prey. Soil SVs were derived using a diversity of approaches and were usually based on the lowest value determined from soil toxicity to terrestrial plants, invertebrates, wildlife, and sometimes microbes. Soil SVs based on toxicity to wildlife were determined from modeled incidental soil ingestion or chemical accumulation in terrestrial organisms. The majority of the reviewed SV compilations were secondary sources of values obtained from a relatively few compilations with independently derived values. The technical basis for SV derivation varied substantially and were generally complex. The SV compilations with a substantial number of independently derived values included the Netherlands Maximum Permissible Concentrations, Canadian Environmental Quality Guidelines, ORNL Preliminary Remediation Goals, and the USEPA Region V Ecological Screening Levels. Ambient Water Quality Criteria and the ecological soil screening levels were independently derived but are comprised of relatively few SVs (9 to 38). Ecological risk practitioners are advised to carefully evaluate the degree of independence of the SVs, the congruence of the basis for the SV with the questions encompassed in the risk assessment, and current revision status of the compilation.