title: Circumpolar contaminant concentrations in polar bears (Ursus maritimus) and potential population-level effects.
abstract: Polar bears (Ursus maritimus) currently receive much attention in the context of global climate change. However, there are other stressors that might threaten the viability of polar bear populations as well, such as exposure to anthropogenic pollutants. Lipophilic organic compounds bio-accumulate and bio-magnify in the food chain, leading to high concentrations at the level of top-predators. In Arctic wildlife, including the polar bear, various adverse health effects have been related to internal concentrations of commercially used anthropogenic chemicals like PCB and DDT. The extent to which these individual health effects are associated to population-level effects is, however, unknown. In this study we assembled data on adipose tissue concentrations of ∑PCB, ∑DDT, dieldrin and ∑PBDE in individual polar bears from peer-reviewed scientific literature. Data were available for 14 out of the 19 subpopulations. We found that internal concentrations of these contaminants exceed threshold values for adverse individual health effects in several subpopulations. In an exploratory regression analysis we identified a clear negative correlation between polar bear population density and sub-population specific contaminant concentrations in adipose tissue. The results suggest that adverse health effects of contaminants in individual polar bears may scale up to population-level consequences. Our study highlights the need to consider contaminant exposure along with other threats in polar bear population viability analyses.
authors.affiliation: Department of Environmental Science, Institute for Water and Wetland Research (IWWR), Radboud University (RU), NL-6500 GL Nijmegen, The Netherlands; Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 7608 PB Wageningen, The Netherlands. Electronic address: Rascha.nuijten@gmail.com.
authors.forename: R J M
authors.initials: RJM
authors.lastname: Nuijten
authors.affiliation: Department of Environmental Science, Institute for Water and Wetland Research (IWWR), Radboud University (RU), NL-6500 GL Nijmegen, The Netherlands.
authors.forename: A J
authors.initials: AJ
authors.lastname: Hendriks
authors.affiliation: Department of Biology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway; Department of Arctic Technology, The University Centre in Svalbard, Longyearbyen, Norway.
authors.forename: B M
authors.initials: BM
authors.lastname: Jenssen
authors.affiliation: Department of Environmental Science, Institute for Water and Wetland Research (IWWR), Radboud University (RU), NL-6500 GL Nijmegen, The Netherlands; PBL Netherlands Environmental Assessment Agency, PO Box 303, 3720 AH Bilthoven, The Netherlands.
authors.forename: A M
authors.initials: AM
authors.lastname: Schipper
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry*; D000818:Animals; D001110:Arctic Regions; D003634:DDT / Q000032:analysis; D004026:Dieldrin / Q000032:analysis; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis*; D005260:Female; D055768:Halogenated Diphenyl Ethers / Q000032:analysis; D011078:Polychlorinated Biphenyls / Q000032:analysis; D011156:Population Density; D001503:Ursidae
chemical_list: D004785:Environmental Pollutants; D055768:Halogenated Diphenyl Ethers; C086401:pentabromodiphenyl ether; D003634:DDT; D011078:Polychlorinated Biphenyls; D004026:Dieldrin
keywords: Arctic; Bioaccumulation; DDT; Dieldrin; PBDE; PCB; Polar bear; Pollution; Population effects; Ursus maritimus