ИСТИНА

Being at the top of the marine food chain, Arctic foxes tend to accumulate considerable amounts of persistent organic pollutants (POPs) due to biomagnification. The Mednyi Island (area: 186 sq. km) in the Bering Sea is at present uninhabited, although there existed a village until 1970. Arctic foxes of the Mednyi Island belong to an endangered subspecies (Vulpes lagopus semenovi) and form an isolated insular population. Their diet largely consists of fulmars (Fulmarus glacialis) and their eggs. We were interested in determining the levels of selected POPs in the fauna of this remote island in the absence of local pollution sources. The levels of polychlorodibenzodioxins/furans (PCDD/PCDFs) and dioxin-like polychlorobiphenyls (dl-PCBs) were measured in the livers of Arctic foxes (n = 2) and fulmars (n = 5) collected on the Mednyi Island. The PCDD/DF levels (pg/g TEQ w/w) were 57.9 ± 8.9 (in fulmar livers), 152.0 (adult male fox) and 736.5 (adult female fox). The contribution of dl-PCBs to the total TEQ sum was ca. 8%. The main PCDD/PCDF congener that contributed the most to the sum TEQ in all cases was 2,3,4,7,8-pentaCDF (50 – 70% of the total TEQ). The only other significant congeners in fox livers were hexaCDFs, whereas in fulmar livers 1,2,3,7,8-pentaCDD contributed up to 30% of total TEQ. In general, the congener concentration profiles for Arctic foxes and fulmars were similar to each other. This confirms the biomagnification hypothesis of PCDD/DFs accumulation, although 1,2,3,7,8-pentaCDD seems to be efficiently metabolized by the Arctic fox liver. Previously, dioxin levels were reported in fulmar livers from the Canadian Arctic. The total TEQ was 138 ± 19 pg/g w/w, of which ca. 80% contributed pentaCDFs (Braune et al., 2010). A comparison with our data suggests that the Mednyi Island may be less polluted than other Arctic areas, but the congener profiles indicate the global nature of pollution, in particular due to pentaCDFs.