Possible immunotoxic effects of organochlorines in polar bears (Ursus maritimus) at Svalbard

Associations between immunoglobulin G (IgG) levels and the organochlorine c ontaminants (OCs) polychlorinated biphenyls (PCBs), chlordanes, 1,1-dichlor o-2,2-bis(4-chlorophenyl) ethylene (DDE), hexachlorobenzene (HCB), and hexa chlorocyclohexanes (HCHs) in blood plasma from polar bears caught at Svalba rd were determined. The blood samples were collected from free-living polar bears of different age and sex between 1991 and 1994. The IgC concentratio n increased with age and was significantly higher in males than in females, IgC war negatively correlated with Sigma PCB level and with three individu al PCB congeners, IUPAC numbers 99, 194, and 206. HCB was also negatively c orrelated with IgG. The significant negative OC correlation with IgG levels may indicate an immunotoxic effect.