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(10-01) Effects of nutrients on PCB bioaccumulation for benthivorous fish. Moermond, Caroline*,1, Roozen, Frank1, Zwolsman, John2, Koelmans, Albert1, 1 Wageningen University, P.O.Box 8080, 6700 DD, Wageningen, The Netherlands2 RIZA, Dordrecht, The Netherlands ABSTRACT- In floodplain lakes, variation in nutrient loadings may influence both benthic and pelagic food web structures, which in turn may alter fate and availability of contaminants. Because of their feeding behaviour, benthivorous fish may be an important link between these benthic and pelagic foodwebs. For management purposes, it is important to know the extent at which contaminants are remobilized into (a)biotic compartments of floodplain lakes. The primary objective of this research was to assess the influence of nutrient additions on bioaccumulation of sediment-bound PCBs in benthivorous fish. The secondary objective was to evaluate the potential of labile PCB fractions in predicting PCB accumulation in benthivorous fish. To this end, accumulation experiments with carp (Cyprinus carpio) were performed in enclosures placed in a floodplain lake along the river Waal in the Netherlands. Results show that within the duration of the experiment, the carp have taken up a significant amount of PCBs. Bioaccumulation of PCBs by carp correlated significantly to total extractable PCB concentrations in sediments. However, accounting for labile fractions (through a Tenax ® extraction technique), caused significance levels to improve by at least a factor 50. Nutrient additions significantly affected the amount of PCBs taken up in the carp relative to the Tenax-extractable concentrations in sediment. When more nutrients were added, the relative amount of PCBs in carp increased. Calculations with benthic invertabrate PCB concentrations show that carp exposure to PCBs must have been both direct (through sediments and water) and indirect (through ingestion of benthic invertebrates). Although it is not possible to draw decisive conclusions, several explanations for the fact that higher nutrient additions increase the relative amount of PCBs in carp can be provided. Key words: pcb bioaccumulation, trophic state, fate, fish |
