title: PCBs and OH-PCBs in polar bear mother-cub pairs: a comparative study based on plasma levels in 1998 and 2008.
abstract: The aim of this study was to examine the plasma concentrations and prevalence of polychlorinated biphenyls (PCBs) and hydroxylated PCB-metabolites (OH-PCBs) in polar bear (Ursus maritimus) mothers (n=26) and their 4 months old cubs-of-the-year (n=38) from Svalbard to gain insight into the mother-cub transfer, biotransformation and to evaluate the health risk associated with the exposure to these contaminants. As samplings were performed in 1997/1998 and 2008, we further investigated the differences in levels and pattern of PCBs between the two sampling years. The plasma concentrations of Σ(21)PCBs (1997/1998: 5710 ± 3090 ng/g lipid weight [lw], 2008: 2560 ± 1500 ng/g lw) and Σ(6)OH-PCBs (1997/1998: 228 ± 60 ng/g wet weight [ww], 2008: 80 ± 38 ng/g ww) in mothers were significantly lower in 2008 compared to in 1997/1998. In cubs, the plasma concentrations of Σ(21)PCBs (1997/1998: 14680 ± 5350 ng/g lw, 2008: 6070 ± 2590 ng/g lw) and Σ(6)OH-PCBs (1997/1998: 98 ± 23 ng/g ww, 2008: 49 ± 21 ng/g ww) were also significantly lower in 2008 than in 1997/1998. Σ(21)PCBs in cubs was 2.7 ± 0.7 times higher than in their mothers. This is due to a significant maternal transfer of these contaminants. In contrast, Σ(6)OH-PCBs in cubs were approximately 0.53 ± 0.16 times the concentration in their mothers. This indicates a lower maternal transfer of OH-PCBs compared to PCBs. The majority of the metabolite/precursor-ratios were lower in cubs compared to mothers. This may indicate that cubs have a lower endogenous capacity to biotransform PCBs to OH-PCBs than polar bear mothers. Exposure to PCBs and OH-PCBs is a potential health risk for polar bears, and the levels of PCBs and OH-PCBs in cubs from 2008 were still above levels associated with health effects in humans and wildlife.
authors.affiliation: Norwegian University of Science and Technology (NTNU), Department of Biology, Høgskoleringen 5, NO-7491 Trondheim, Norway. jenny.bytingsvik@bio.ntnu.no
authors.forename: Jenny
authors.initials: J
authors.lastname: Bytingsvik
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lie
authors.forename: Jon
authors.initials: J
authors.lastname: Aars
authors.forename: Andrew E
authors.initials: AE
authors.lastname: Derocher
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Wiig
authors.forename: Bjørn M
authors.initials: BM
authors.lastname: Jenssen
mesh_terms: D000818:Animals; D000833:Animals, Suckling / Q000097:blood*; D004785:Environmental Pollutants / Q000097:blood*; D004787:Environmental Pollution / Q000706:statistics & numerical data; D005260:Female; D008297:Male; D011078:Polychlorinated Biphenyls / Q000097:blood*; D018709:Statistics, Nonparametric; D013538:Svalbard; D001503:Ursidae / Q000097:blood*
chemical_list: D004785:Environmental Pollutants; D011078:Polychlorinated Biphenyls