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3D - Exposure and effects of environmental contaminants in marine organisms (TU7/1) Comparing bioavailability and biotransformation of sediment-associated polycyclic aromatic hydrocarbons in a polychaete and an echinoderm. Selck, Henriette1, Palmqvist, Annemette1, Granberg, Maria2, Forbes, Valery1, 1 Dept. of Life Sciences and Chemistry, Roskilde University, Roskilde, Denmark2 Dept. of Marine Ecology, Göteborg University, KMRS, Fiskebäckskil, Sweden ABSTRACT- PAHs are widely distributed in the marine environment and have properties that make them likely to adsorb to organic matter, accumulate in sediment and to bioaccumulate. Due to their feeding strategy deposit-feeders may be exposed to high concentrations of sediment-associated contaminants and may, therefore, be important in facilitating the removal of organic contaminants from sediment. Once taken up by an organism the fate and effects of organic compounds are especially dependent on their susceptibility to biotransformation. We compared Flu uptake and biotransformation capability between a polychaete, Capitella sp. I, and an echinoderm, Amphiura filiformis, which both constitute a major food for demersal fish and other bottom feeders. Tissue homogenates were extracted into 4 fractions: parent Flu (untransformed), polar- (phase I products), aqueous- (phase II products) Flu metabolites, and tissue residue Flu (unextractable). The total Flu body-burden in A. filiformis (after 45 days) was very low compared to in Capitella sp. I (after 5 days) despite exposure to a similar sediment concentration (30 Key words: Bioaccumulation, PAH, Biotransformation, Benthos |
g Flu/g. dry wt. sed.). Overall, Capitella decreased the proportion of parent Flu, and increased the proportion of polar- and especially aqueous Flu-metabolites suggesting rapid biotransformation of Flu. Biotransformation was very limited in A. filiformis, where parent Flu by far contributed the largest fraction. We estimate that remobilization of sediment-associated Flu by A. filiformis would be ca. 0.029 mg total Flu equivalents m-2 y-1, and by Capitella sp. I ca. 5.64 mg Flu eq. m-2 y-1. These results highlight the importance of particle ingestion as a pathway whereby contaminants can enter benthic food webs.