PARENT SESSION
TA7 - Soil Toxicology and Risk Assessment
Chair: Efroymson , Rebecca1, 1 Oak Ridge National Laboratory, Oak Ridge, TN
Co-chair: Sample, Bradley2, 2 CH2M Hill/Sacramento, Sacramento, CA
8:00 AM to 12:00 PM - Tuesday, 19 November 2002
Room Ballroom A
(391) Benchmark values for deriving soil invertebrate Ecological Soil Screening Levels for antimony, barium, beryllium, manganese.
Checkai, Ronald*,1, Kuperman, Roman2, Simini, Michael2, Phillips, Carlton1, Speicher, Jason3, Barclift, David3, 1 U.S. Army Edgewood Chemical Biological Center, Aberdeen Proving Ground, MD, USA2 GEO-CENTERS, Inc., Aberdeen Proving Ground, MD, USA3 U.S. Navy Engineering Field Activity Northeast, Lester, PA, USA
ABSTRACT- The U.S. Environmental Protection Agency (USEPA) is developing Ecological Soil Screening Level (Eco-SSL) benchmarks for ecological risk assessment (ERA) of contaminants at Superfund sites. The Eco-SSL derivation process represents the collaborative effort of a multi-stakeholder workgroup consisting of USEPA, DoD (Army, Navy, Air Force), DOE, State, private industry, and academic participants. Eco-SSLs are ecotoxicity values that can be used routinely in screening-level ERA to identify those contaminants in soil that warrant additional evaluation in a baseline ERA, and to eliminate those that do not. Eco-SSLs are developed from literature values whenever sufficient quantity and quality of data exist. Insufficient data were available on the toxicity of antimony (Sb), barium (Ba), beryllium (Be), and manganese (Mn) to soil invertebrates, necessitating toxicity testing. Ecotoxicity tests were conducted under conditions maximizing compliance with Eco-SSL evaluation criteria, using a Sassafras sandy loam soil that supports relatively high bioavailability of Sb, Ba, Be, and Mn. Soils were amended with soluble metal salt, respectively, then aged/weathered to better reflect contaminant exposure at Superfund sites. Bioassays used include enchytraeid reproduction (ISO/16387:2001) measuring juvenile production by the potworm Enchytraeus crypticus, earthworm cocoon production (ISO/11268-2:1998) by Eisenia fetida, and collembola reproduction (ISO/11267:1998) measuring juvenile production by Folsomia candida. These tests measured the toxicity of soil contaminants to ecologically relevant test species during chronic assay of reproductive measurement endpoints. EC20 values (mg kg-1 for potworm / earthworm / collembola, respectively) were Sb (194 / 30 / 81), Ba (585 / 370 / 165), Be (45 / 52 / 28), and Mn (116 / 730 / 1200). Based on these data, draft-final Eco-SSL benchmarks (mg kg-1) for soil invertebrates are Sb (78), Ba (330), Be (40), and Mn (470). Results of these studies and resulting draft-final benchmarks will undergo quality control review by the Eco-SSL task group before inclusion in the Eco-SSL database.
Key words: Eco-SSL, soil toxicity, soil invertebrates, metals