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(W/MF165) Mobilisation of PCB during winter emaciation of anadromous Arctic charr: tissue re-distribution and biological responses. Jørgensen, Even1, Foshaug, Hanne2, Burkow, Ivan2, Jobling, Malcolm3, 1 2 3 ABSTRACT- The migratory life strategy of the anadromous Arctic charr (Salvelinus alpinus) is characterised by substantial growth and lipid deposition during the short summer residence in seawater, and a subsequent depletion of the body lipid stores during over-wintering in freshwater. It is generally known that lipid mobilisation may lead to a redistribution of deposited POPs from adipose tissues toward vital organs (e.g. brain) and hence carry a risk of increased pollutant-associated stress. In order to study these processes in fish under ecologically relevant conditions the following experiment has been conducted: Wild, anadromous charr were captured at return from seawater in July and contaminated with PCB (0, 0.1, 10 and 50 mg/kg fish). Thereafter the fish were transferred to indoor tanks where they were held without being fed at natural light and temperature conditions throughout the winter. Then fish were sacrificed in October, February and May for analyses of lipid mobilisation and tissue distribution of PCB, and dose-related hepatic cytochrome CYP1A responses. The results showed that there were a strong increase in liver and brain concentrations of PCB throughout the winter, indicating an enhanced toxic potential of deposited PCBs along with lipid mobilisation. An enhanced biological response to PCB was also evidenced by the finding of a strong potentiation of hepatic CYP1A responses to PCB throughout the winter. These processes must be taken into account when designing projects aimed at ecotoxicological testing of wild fish, and when using the CYP1A activity as a biomarker in environmental monitoring. Key words: Arctic charr, PCB, emaciation, toxicokinetics |
