Organohalogen concentrations and a gross and histologic assessment of multiple organ systems in East Greenland polar bears (Ursus maritimus)

To investigate the relation between biological parameters, not earlier investigated in the polar bear, and organohalogen pollution in East Greenland polar bears, we initiated a sampling of adipose tissue, internal organs and skulls from more than 100 free-ranging polar bears killed by local subsistence hunters from Central East Greenland (69 ̊00’N to 74 ̊00’N) during 1999-2002. The present thesis exposes the first and most important results from this large multidisciplinary study of this material, and evaluates the possible connection between the relatively high levels of organohalogens in the adipose tissue and pathological changes in skulls and internal organs. Our results suggested a decrease in adipose tissue concentrations of organohalogens in East Greenland polar bears from 1990 to 1999-2001. Two of the biological effect parameters (FA and enlarged clitoris) did not indicate a link to the relatively high levels of organohalogens. But, there was indications of strong relationships between various organohalogen compounds and skull mineral density indicating disruption of the bone mineral composition. The histopathological changes found in liverand kidney tissue were a result of ageing, infectious agents, season and meaby chronic exposure to organohalogens. These result fill out an existing knowledge gap in potential effects of environmental, organic contaminants on fluctuating asymmetry, bone mineral density and functional anatomy (histology) in the polar bear. In addition, the results may have a large social importance for Inuits as well.