Toxicokinetics and Effects of PCBs in Arctic Fish: A Review of Studies on Arctic Charr

Abstract

In a series of environmentally realistic laboratory experiments, toxicokinetics and effects of polychlorinated biphenyls (PCBs) were studied in the Arctic charr (Salvelinus alpinus). Winter fasting and emaciation, which are common among Arctic charr living in high latitudes, resulted in a redistribution of the lipophilic PCBs from lipid-storing tissue such as the muscle, to vital organs that must be considered sensitive toward PCB (liver and brain). This redistribution was accompanied by a significant potentiation of the hepatic cytochrome P-450 (CYP) 1A biomarker response, from low activities in October (within those measured in uncontaminated charr) to a high, probably maximum, induction in May. Performance studies demonstrated a clear effect of environmentally realistic PCB levels on endocrine mechanisms, immune function, and seawater preadaptation (smoltification) in charr that had been feed deprived for several months after contamination with Aroclor 1254, whereas a high PCB dose exerted only minor, if any, effects in charr that had been fed after contamination. These results demonstrate that emaciation results in decreased dose-response relationships in fish, and indicate that arctic animals undergoing seasonal cycles of “fattening” and emaciation may be extra sensitive toward persistent, lipophilic organochlorines. Pilot studies on Arctic charr from Bjørnøya Island revealed marked CYP1A biomarker responses and an upregulation of genes involved in cellular homeostatic mechanisms in charr from Lake Ellasjøen (high PCB levels).

Thanks are extended to the staff at Talvik Research Station, and at Kårvik Research Station, for their skilled production of Arctic charr smolts and proper care of the fish during the experiments. We thank Judith Wolkers, Hans Wolkers, Jo Espen Tau Strand, and Steve Wiseman for help with analyses, and John Leatherland, who kindly provided us access to his laboratory for GH analyses. Thanks are also extended to Anita Evenseth and Guttorm Christensen for capturing fish for us at Bjørnøya. The study was supported by funding from the National Science Foundation, USA, project OPP-9908890; the Norwegian Research Council, projects 114263/72, 151462/720, 135388/730, and 135453/730; and the Natural Science and Engineering Research Council (NSERC), Canada, Discovery and Strategic grants. Any opinions, findings and conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

Notes

Skotvold, T., Wartena, E. M. M, Christensen, G. N., Fjeld, E., and Schlaback, M. 1999. Organochlorine contaminants in biota and sediment from lakes on Bear Island. Akvaplan niva report 510.1443.1.