Geographical trends in levels of
PCB
10 (sum of 10 majorcongeners), hexachlorocyclohexanes (HCH),
DDT (sumof DDT-related compounds), and other persistent organochlorines (OCs) in ringed seal blubber were examinedat 13 sampling locations in the Arctic over 175 deg longitudefrom northern Canada to the South Kara Sea (YeniseyGulf) in Russia. Concentrations of OCs were adjusted, usinganalysis of covariance, for effects of the covariates, sex,age, and blubber thickness. Adjusted mean concentrationsof
PCB
10 and
DDT were significantly higher in thesamples from the Yenisey Gulf in the Russian Arctic,Svalbard, and East Greenland than in west Greenland orthe Canadian Arctic.
PCB
10 and
DDT in Yenisey Gulf sampleswere 8× and 6× higher, respectively, than the averagein levels from four Canadian locations.
PCB
10 and
DDTmeans declined significantly with increasing westerlylongitude (
r 2 = 0.75 and 0.73, respectively).
HCH levelsfor sites in the Canadian Arctic were significantly higher thanthose from west Greenland (Qeqertarsuaq), east Greenland(Ittoqqortoormiit), and Svalbard and increased significantlyfrom east to west. The geographical trend
HCH is in generalagreement with observed trends of HCH in seawaterwhere higher levels have been found in the Canadian Arctic.Higher proportions of more recalcitrant hexa- andpentachloro-PCB congeners were observed in seal blubbersamples in the European/Russian Arctic. The continueduse of PCBs in electrical equipment and other applicationsin Russia is a likely source of the more highly chlorinatedcongeners.