Some heavy metals, essential elements, and chlorinated hydrocarbons in polar bear ( Ursus maritimus) at Svalbard

Abstract

During the period 1978–1989, samples of liver, kidney and subcutaneous fat from 24 polar bears, Ursus maritimus, from Svalbard were analysed for mercury, cadmium, lead, copper, zinc, selenium, arsenic, HCB, DDE, PCBs (as Aroclor 1260 R or Phenoclor DP6 R). In a selected number of liver (seven) and fat (three) samples, the composition of individual PCB congeners was studied by comparison with 23 individual PCB congeners (IUPAC nos 28, 52, 74, 101, 99, 110, 149, 118, 114, 105, 153, 141, 138, 187, 128, 183, 156, 157, 180, 170, 194, 206 and 209). In the seven liver samples, the concentrations of o, p′-and p, p′-isomers of DDT, TDE, DDE, α-, β- and γ-HCH, oxychlordane, heptachlor, heptachlorepoxide, aldrin and dieldrin were also determined. The hepatic concentrations of mercury, cadmium and lead in animals of all ages were 0·4–6·0, <0·1–1·2, and <0·5–1·6 μg g −1, respectively. This indicates a moderate exposure. Concentrations of mercury and selenium were correlated ( r = 0·80). The levels of copper and zinc represented normal physiological concentrations. The concentrations of HCB, DDE and PCBs in fat were <0·05–1·5, <0·1–3·4 and 2·9–90 μg g −1, respectively. The corresponding results for liver were <0·01–0·11, <0·1–0·5 and 0·1–78 μg g −1, respectively. Six PCB congeners, PCB-99, −153, −138, −180, −170, and, −194 accounted for about 99 and 87% of the total PCB content (sum of the 12 congeners, nos. 28, 99, 153, 138, 128 + 187, 156, 157, 180, 170, 194, 206 and 209) in liver and fat, respectively. PCB-153 represented 37±3 and 30±16% of the sum PCB (sum of 12 congeners) in liver and fat, respectively. The range of the hepatic concentration of oxychlordane was 5–19 μg g −1. Quantifiable concentrations of heptachlor, heptachlorepoxide, β-HCH and dieldrin were also found in all the liver samples analysed. Low concentrations of p, p′- and o, p′-DDT were found in two of seven liver and two of two fat samples. Comparisons are made with investigations from Canada and Greenland. Possible effects of PCBs, especially on reproduction, cannot be excluded. Ringed seal, Foca hispida, and to some extent bearded seal, Erignathus barbatus, are the main food of the polar bear. It is therefore likely that the exposure to environmental pollutants occurs via the consumption of these two species.