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CRITICAL BODY RESIDUES FOR FRESHWATER AND SALTWATER AMPHIPODS EXPOSED TO SEDIMENT CONTAINING A MIXTURE OF HIGH KOW PAHS
Citation:
Spehar, R L., D. R. Mount, M. K. Lukasewycz, V R. Mattson, E N. Leonard, L P. Burkhard, R M. Burgess, J R. Serbst, AND W J. Berry. CRITICAL BODY RESIDUES FOR FRESHWATER AND SALTWATER AMPHIPODS EXPOSED TO SEDIMENT CONTAINING A MIXTURE OF HIGH KOW PAHS. Presented at SETAC 8th Annual Meeting, Bloomington, MN, April 13-14, 2000.
Description:
Sediments were spiked with a mixture of 13 high log Kow (5.4-6.8) PAH compounds to determine critical body residues (CBR) in Hyalella azteca and Leptocheirus plumulosus. Hyalella were exposed for 28 d in a intermittent flow test and for 10 d in a static test to compare PAH uptake under both exposure methods. A 10 d static test with Leptocheirus also was conducted so that CBRs for each species could be compared under similar test conditions. Exposure concentrations of 4.2, 2.7, 1.6, 0.8, 0.4, 0.2 and 0.1 toxic units (TUs) for Hyalella were projected from the equilibrium partitioning (EqP) and narcosis models. In the intermittent-flow exposure with Hyalella, measured pore water concentrations on day 0 were similar to predicted values for each compound but toxicity and whole body residues after 10 and 28 d were less than predicted from sediment concentrations for all but two compounds suggesting that metabolism occurred. Significant mortality and growth effects in this test occurred at 20-35 umol/g lipid, values close to literature values of 30-60 umol/g lipid. In static tests, greater toxicity occurred to Hyalella suggesting that there was greater exposure than in the intermittent-flow test. Significant mortality (56-63%) was observed in both species after 10 d at 1 TU indicating that these compounds were nearly strictly additive, as was predicted by narcosis modeling. Results are discussed in the context of using EqP and narcosis modeling for assessing the risk of PAH mixtures including those with high Kow.