Chlorinated Hydrocarbon Contaminants in Polar Bears from Eastern Russia, North America, Greenland, and Svalbard: Biomonitoring of Arctic Pollution

Abstract

Adipose tissue samples from polar bears (Ursus maritimus) were obtained by necropsy or biopsy between the spring of 1989 to the spring of 1993 from Wrangel Island in Russia, most of the range of the bear in North America, eastern Greenland, and Svalbard. Samples were divided into 16 regions corresponding as much as possible to known stocks or management zones. Concentrations of dieldrin (DIEL), 4,4'-DDE (DDE), sum of 16 polychlorinated biphenyl congeners (sigma PCB), and sum of 11 chlordane-related compounds and metabolites (sigma CHL) were determined. In order to minimize the effect of age, only data for adults (320 bears age 5 years and older) was used to compare concentrations among regions. Concentrations of sigma PCB were 46% higher in adult males than females, and there was no significant trend with age. Concentrations of sigma CHL were 30% lower in adult males than females. Concentrations of sigma PCB, sigma CHL, and DDE in individual adult female bears were standardized to adult males using factors derived from the least-square means of each sex category, and geometric means of the standardized concentrations on a lipid weight basis were compared among regions. Median geometric mean standardized concentrations (lipid weight basis) and ranges among regions were as follows: sigma PCB, 5,942 (2,763-24,316) micrograms/kg; sigma CHL, 1,952 (727-4,632) micrograms/kg; DDE, 219 (52-560) micrograms/kg; DIEL, 157 (31-335) micrograms/kg. Geometric mean sigma PCB concentrations in bears from Svalbard, East Greenland, and the Arctic Ocean near Prince Patrick Island in Canada were similar (20,256-24,316 micrograms/kg) and significantly higher than most other areas. Atmospheric, oceanic, and ice transport, as well as ecological factors may contribute to these high concentrations of sigma PCB. sigma CHL was more uniformly distributed among regions than the other CHCs. Highest sigma CHL concentrations were found in southeastern Hudson Bay, which also had the highest DDE and DIEL concentrations. In general, concentrations of sigma CHL, DDE, and DIEL were higher in eastern than western regions, suggesting an influence of North American sources. Average sigma PCB concentrations in bears from the Canadian Arctic were similar to those in 1982-84, while average sigma CHL and DDE concentrations were 35-44% lower and DIEL was 90% lower. However, the significance of these temporal trends during the 1980s is not conclusive because of the problems of comparability of data.

Trends of polyfluoroalkyl compounds in marine biota and in humans

“…Furthermore, ringed seals are an important prey source for polar bears that have been shown to be the highest contaminated marine mammals. [77,81,82] Butt et al reported that mean concentrations were similar between ringed seal populations in the Canadian Arctic (11 locations, 10 liver samples per site). Concentrations of PFNA and PFUnDA generally ranged between 1 and 10 ng g À1 ww, whereas PFTriDA was less than 1 ng g À1 ww and PFOS concentrations were mainly between 10 and 40 ng g À1 ww.…”

Concentrations and patterns of organochlorine contaminants in white whales (Delphinapterus leucas) from Svalbard, Norway

“…et al, 1992a;Wolkers et al, 1998 and polar bears Ž . Norstrom et al, 1998 . The lack of relationship between body length and concentrations of different OC concentrations in this study is consistent with previous Ž studies of white whales Stern et al, 1994;Muir et .…”

“…Likewise, OC bur-Ž . dens in polar bears Ursus maritimus from Svalbard are higher than in their Canadian or Alaskan Ž counterparts Norheim et al, 1992;Kleivane et al, 1994;Bernhoft et al, 1997;Norstrom et al, . 1998 .…”

Chlorinated hydrocarbon contaminants and metabolites in polar bears (Ursus maritimus) from Alaska, Canada, East Greenland, and Svalbard: 1996−2002

“…as recently reviewed by Braune et al (2005-this issue) the polar bear serves as an ideal sentinel species for biomonitoring spatial and temporal trends of CHCs, such as chlordane (CHL)-related compounds and polychlorinated biphenyls (PCBs), as a result of its wide distribution throughout the Arctic and Subarctic and its key role as apex predator in the marine environment (de March et al, 1998;Muir et al, 1999;Muir and Norstrom, 2000;Fisk et al, 2003;AMAP, 2004). As described in Norstrom et al (1998), there are discrete populations of polar bears in the Canadian Arctic. Combined with knowledge of sea ice and land barriers, 12 polar bear management zones were defined.…”