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DEVELOPING SOIL SCREENING LEVELS FOR SOIL INVERTEBRATES AND PLANTS
Citation:
Checkai, R. T., M. Swindoll, S. Ells, C. Falco, S C. Foster, D. Gannon, L. A. Kapustka, R. G. Kuperman, R. Lee, C L. Russom, J. Speicher, G. Stephenson, AND R. S. Wentsel. DEVELOPING SOIL SCREENING LEVELS FOR SOIL INVERTEBRATES AND PLANTS. Presented at Society for Risk Analysis Annual Meeting, Arlington, VA, December 3-6, 2000.
Description:
U.S. Environmental Protection Agency (USEPA), as part of a collaborative effort among USEPA, DoD, DOE, states, universities and industry, is developing Ecological Screening Levels (Eco-SSLs) for approximately 24 of the most common contaminants founrd at Superfund sites. Eco-SSLs serve as a tool to identify soil contaminant levels that warrant further site assessment, and to eliminate those that do not. As part of this effort, a process for deriving Eco-SSLs using data from ecotoxicity studies on soil invertebrates and plants has been developed. The multi-step process begins with a thorough literature search and retrieval effort based on key words. Retrieved papers are screened using eight "acceptance" criteria, designed to identify studies having appropriate information and sufficient detail to facilitate inter-study comparisons. A study must meet all acceptance criteria to be included in the data set. Acceptable papers are then scored accordding to nine technical "evaluation" criteria. For each criterion, the study is scored 0, 1 or 2 based on degree of agreement with each individual criterion. Studies with total scores of >10 out of the possible 18 are considered of sufficient quality for deriving an Eco-SSL. Toxicity data from these studies are ranked by both treatment effects (e.g., reproduction, growth, etc.) and toxicity parameter (e.g. NOEC, EC10, etc.), and assigned a confidence level (A-D). Acute effects data are not considered appropriate for deriving an Eco-SSL. Finally, an Eco-SSL is derived by calculating the geometric mean of the chronic effects data rated at the highest confidence level (e.g., A, B) for which there is a sufficient number of data points (N>3). The Eco-SSLs and a technical discussion for each of these soil contaminants and receptors are being developed for an USEPA Superfund Guidance document. The technical discussions compare Eco-SSLs to background concentrations across the USA, and nutrient requirements when appropriate. Technical discussions also address bioavailability issues, ecotoxicity issues (mode of action), assessment of the data used to derive each Eco-SSL, and the utilization of the Eco-SSLs to screen COPCs at Superfund sites during initial stages of Ecological Risk Assessment. The Eco-SSL effort includes a QA/QC review to ensure the appropriateness and accuracy of the Eco-SSL derivation process.