Geographical trends in levels of ΣPCB10 (sum of 10 major
congeners), hexachlorocyclohexanes (HCH), ΣDDT (sum
of DDT-related compounds), and other persistent organochlorines (OCs) in ringed seal blubber were examined
at 13 sampling locations in the Arctic over 175 deg longitude
from northern Canada to the South Kara Sea (Yenisey
Gulf) in Russia. Concentrations of OCs were adjusted, using
analysis of covariance, for effects of the covariates, sex,
age, and blubber thickness. Adjusted mean concentrations
of ΣPCB10 and ΣDDT were significantly higher in the
samples from the Yenisey Gulf in the Russian Arctic,
Svalbard, and East Greenland than in west Greenland or
the Canadian Arctic. ΣPCB10 and ΣDDT in Yenisey Gulf samples
were 8× and 6× higher, respectively, than the average
in levels from four Canadian locations. ΣPCB10 and ΣDDT
means declined significantly with increasing westerly
longitude (r
2 = 0.75 and 0.73, respectively). ΣHCH levels
for sites in the Canadian Arctic were significantly higher than
those from west Greenland (Qeqertarsuaq), east Greenland
(Ittoqqortoormiit), and Svalbard and increased significantly
from east to west. The geographical trend ΣHCH is in general
agreement with observed trends of HCH in seawater
where higher levels have been found in the Canadian Arctic.
Higher proportions of more recalcitrant hexa- and
pentachloro-PCB congeners were observed in seal blubber
samples in the European/Russian Arctic. The continued
use of PCBs in electrical equipment and other applications
in Russia is a likely source of the more highly chlorinated
congeners.
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