Geographic variation of PCB congeners in polar bears (Ursus maritimus) from Svalbard east to the Chukchi Sea

We present data on geographic variation in polychlorinated biphenyl (PCB) c ongeners in adult female polar bears (Ursus maritimus) from Svalbard eastwa rd to the Chukchi Sea. Blood samples from 90 free-living polar bears were c ollected in 1987-1995. Six PCB congeners, penta to octa chlorinated (PCB-99 , -118, -153, -156, -180, -194), were selected for this study. Differences between areas were found in PCB levels and congener patterns. Bears from Fr anz Josef Land (11,194 ng/g lipid weight) and the Kara Sea (9,412 ng/g 1w) had similar Sigma PCB levels and were higher than all other populations (Sv albard 5,043 ng/g 1w, East Siberian Sea 3,564 ng/g 1w, Chukchi Sea 2,465 ng /g 1w). Svalbard PCB levels were higher than those from the Chukchi Sea. Ou r results, combined with earlier findings, indicate that polar bears from F ranz Josef Land and the Kara Sea have the highest PCB levels in the Arctic. Decreasing trends were seen eastwards and westwards from this region. Of t he congeners investigated in the present study, the lower chlorinated PCBs are increasing and the high chlorinated PCBs are decreasing from Svalbard e astward to the Chukchi Sea. Different pollution sources, compound transport patterns and regional prey differences could explain the variation in PCB congener levels and patterns between regions.