Human and Ecological Risk Assessment - Earthjustice

Appendix HEcological Benchmarkshave confirmed that amphibians are among the most sensitive taxa to metals found in CCW, andselenium appears to be a significant stressor in CCW disposal scenarios. The endpointsconsidered in these studies were related to population sustainability and, consequently, are highlyrelevant to ecological risk assessment. However, these field studies were confounded by the factthat wildlife were exposed to multiple chemical pollutants (including radionuclides) and, as aresult, acute effects data on individual metals remain the most appropriate source for quantitativebenchmarks to assess the potential for adverse effects in amphibians.Sediment Community BenchmarksFor the sediment community, benchmarks were selected based on a complete assessmentof several sources proposing sediment benchmark values. Primary sources evaluated fordeveloping sediment community benchmarks are shown in Table H-2.Table H-2. Primary Sources Evaluated for Developing Sediment Community BenchmarksLong, E.R., and L.G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed ContaminantsTested in the National Status and Trends Program. Technical Memorandum NOS OMA 52. National Oceanicand Atmospheric Administration (NOAA), Washington, DC.Jones, D.S., G.W. Suter, II, and R.N. Hull. 1997. Toxicological Benchmarks for Screening Contaminants ofPotential Concern for Effects on Sediment-Associated Biota: 1997 Revision. Oak Ridge National Laboratory, OakRidge, TN.U.S. EPA (Environmental Protection Agency). 1997. Protocol for Screening Level Ecological Risk Assessment atHazardous Waste Combustion Facilities. Internal Review Draft, February 28. Office of Solid Waste,Washington, DC.U.S. EPA (Environmental Protection Agency). 1995. Technical Support Document for the Hazardous WasteIdentification Rule: Risk Assessment for Human and Ecological Receptors. Office of Solid Waste, Washington,DC.MacDonald, D.D. 1994. Approach to the Assessment of Sediment Quality in Florida Coastal Waters. Volume 1.Florida Department of Environmental Protection, Tallahassee, FL.Algae and Aquatic Plant BenchmarksFor algae and aquatic plants, adverse effects concentrations were identified in the openliterature or from a data compilation presented in Toxicological Benchmarks for ScreeningPotential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision (Suter and Tsao,1996). For most contaminants, studies were not available for aquatic vascular plants, and lowesteffects concentrations were identified for algae. The benchmark for algae and aquatic plants wasbased on (1) an LOEC for vascular aquatic plants or (2) an effective concentration (ECxx) for aspecies of freshwater algae, frequently a species of green algae (e.g., Selenastrumcapricornutum). Because of the lack of data for this receptor group and the differences betweenvascular aquatic plants and algae sensitivity, the lowest value of those identified was usuallychosen.April 2010–Draft EPA document. H-3