PRELIMINARY-RESULTS OF FASTING ON THE KINETICS OF ORGANOCHLORINES IN POLAR BEARS (URSUS-MARITIMUS)

We determined concentrations of polychlorinated biphenyls (PCBs), chlo rdanes (CHLORs), chlorobenzenes (CBzs), hexachlorocyclohexanes (HCHs), and dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDD an d DDE) in the tissues of individual polar bears (Ursus maritimus) befo re and after a lengthy period of fasting. Polar bears are an ideal mod el for such studies. They undergo one of the most extreme fasts known for any mammal and are located at the top of a long food chain, thus b iomagnification of organochlorines (OC) is significant. Adipose tissue and milk were collected from different reproductive classes of adult females (solitary/pregnant, with cubs-of-the-year, with yearling cubs) and were analyzed for organochlorine content. As the fasting period p rogressed and adipose reserves decreased, concentrations of some organ ochlorines in the adipose tissue and milk increased on a lipid weight basis. The transfer of contaminants from mothers to offspring thus als o increases with duration of the fasting period. This phenomenon could adversely influence the survival and growth of cubs during the critic al early phase of their development.