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(W/EH081) Age Class Effects on PCB Bioaccumulation in Fish from an Urban Tidal River. Doelling Brown, Paige1, Crimmins, Bernard1, Foster, Gregory1, Kelso, Donald1, Velinsky, David2, 1 2 ABSTRACT- Bioaccumulation rates of hydrophobic organic compounds such as polychlorinated biphenyls (PCBs) in aquatic foodwebs have been an issue of great interest in recent years. A number of models can predict tissue burdens in biota based on concentrations measured in abiotic compartments, trophic relationships, and partitioning constants. Many of these models estimate the loss terms for PCBs to be nearly zero in fish, as metabolic transformation and depuration rates are extremely low. Analysis of multiple age classes of fish from the Anacostia River, Washington DC, USA showed older fish were enriched in the high molecular weight congeners, suggesting a loss mechanism for low molecular weight PCBs. Whole body composites of fish from the Anacostia were analyzed for congener specific PCBs, which were quantified via a gas chromatograph equipped with an electron capture detector (GC-ECD). Homologues Cl6-Cl9 represented 38% of the tissue residues in sexually mature white perch (Morone americana), compared to 20% in the immature individuals. Lipid mobilization during spawning has been reported to transfer between 5 and 30% of the adult body burden to the egg mass, and it is possible the low molecular weight congeners represent a substantial portion of the transfer. The objective of this paper is to quantify that transfer for the white perch (Morone americana), the pumpkinseed (Lepomis gibbosus), and the spottail shiner (Notropis hudsonius), three species common in the mid-Atlantic estuaries of North America. Although tissue concentrations of PCBs generally increase with age, models and risk assessment based on total PCBs may underestimate the hazard posed by the enrichment of the high molecular weight congeners. Key words: fish, pcbs, bioaccumulation, congener distribution |
