MP6 Landscape-Scale Ecological Risk Assessment
Room 18A/B, Level 4
2:10 PM - 5:30 PM, Monday, 10 November 2003
Chair: Lapustka, Larry ,
(137) Ecological Risk Assessment of DDTs and PCBs at the Palos Verdes Shelf: Sediment and Fish.
Karen, D1, Byron, E1, Arenal, C1, Sample, B1, Hill, T2, Barackman, M2, 1 CH2M Hill, Sacramento, CA, USA2 CH2M Hill, Redding, CA, USA
ABSTRACT- The Palos Verdes Shelf (PVS) is an effluent-affected area of marine sediment off the Palos Verdes peninsula, extending from Point Fermin to Redondo Canyon along the coast of Los Angeles County in southern California. Contamination to the PVS area historically occurred through municipal and industrial effluent containing DDTs, PCBs, trace metals, and organic matter entering from various outfalls along the coast. For this ecological risk assessment, total DDT (tDDT) and total PCB (tPCB) concentrations in sediment, water, and fish tissue were used as exposure point concentrations (EPCs) to estimate risk. These data were compiled from multiple, independent sources that collected data between 1990 and 2003. These data were used to estimate risk to benthic invertebrates, demersal fish, and water-column fish. Risk was estimated for benthic invertebrates using bulk sediment and porewater exposure point concentrations as two lines of evidence. Gross exceedences over site-specific benchmarks as well as the proportion of sediment at the PVS exceeding benchmarks were used to describe risk to benthic invertebrates. Risk to demersal and water column fish was estimated using tissue concentrations and water column concentrations as two lines of evidence. Gross exceedences over tissue residue and water column (i.e. CCC) benchmarks and the proportion of tissue residues exceeding benchmarks at the PVS were used to describe risk to fish.
Key words: organochlorine, ecological risk, fish , sediment