ZINC, CADMIUM, MERCURY AND SELENIUM IN POLAR BEARS (URSUS-MARITIMUS) FROM CENTRAL EAST GREENLAND

Citation
R. Dietz et al., ZINC, CADMIUM, MERCURY AND SELENIUM IN POLAR BEARS (URSUS-MARITIMUS) FROM CENTRAL EAST GREENLAND, Polar biology, 15(3), 1995, pp. 175-185
Citations number
56
Categorie Soggetti
Ecology,Biology
Journal title
ISSN journal
07224060
Volume
15
Issue
3
Year of publication
1995
Pages
175 - 185
Database
ISI
SICI code
0722-4060(1995)15:3<175:ZCMASI>2.0.ZU;2-7
Abstract
Muscle, liver, and kidney tissues from 38 polar bears (Ursus maritimus ) caught in the Scoresby Sound area, Central East Greenland, were anal ysed for zinc, cadmium, mercury and selenium. In general, cadmium conc entrations were low in muscle, liver and kidney tissue, with geometric means (g.m.) of 0.022 (range: < 0.015-0.085), 0.841 (range: 0.092-3.2 9) and 13.1 (range: 1.04-115) mu g Cd/g wet weight (ww) respectively. This finding can be explained by low cadmium levels in the blubber of ringed seals. The concentration of mercury in muscle tissue was low (g .m. 0.071; range: 0.039-0.193 mu g Hg/g ww), whereas concentrations in liver and kidney tissue were relatively high (liver: g.m. 7.87; range : 1.35-24.8 mu g Hg/g ww, and kidney: g.m. 15.2; range: 1.59-66.6 mu g Hg/g ww). Mercury and cadmium were positively correlated with age in liver and kidney. Zinc was positively correlated with age in kidney, a nd selenium was correlated with age in liver. Contrary to other marine mammals, polar bears had higher mercury levels in the kidneys than in the liver. In all three tissues polar bears had significantly lower c admium levels than ringed seals from the same area. Mercury levels wer e likewise significantly lower in the muscle tissue of polar bears tha n in ringed seals, whereas levels in the liver and kidney were signifi cantly higher. The previous geographic trend for cadmium and mercury f ound in Canadian polar bears could be extended to cover East Greenland as well. Hence cadmium levels were higher in Greenland than in Canada , while the opposite was the case for mercury. Greenland polar bears h ad higher mercury and cadmium contents in livers and kidneys than pola r bears from Svalbard. The mercury levels in muscle and liver tissue f rom polar bears from East Greenland were twice as high as found in bea rs from western Alaska, but half the levels found in northern Alaska. Cadmium and zinc were partially correlated in kidney tissue, and this was found for mercury and selenium as well. Cadmium and zinc showed mo lar ratios close to unity with the highest concentrations occurring in kidney tissue, while the levels of zinc exceeded cadmium in muscle an d liver tissue by up to several decades. Mercury and selenium showed m olar ratios close to unity in liver and kidneys.