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-accu...

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Bibliographic Details
Published in:Environmental Research
Main Authors: Nuijten, R.J.M., Hendriks, A.J., Jenssen, B.M., Schipper, A.M.
Format: Article in Journal/Newspaper
Language:English
Published: 2016
Subjects:
Polar bear
Ursus maritimus
Population effects
Pollution
Bioaccumulation
Arctic
PCB
DDT
Dieldrin
PBDE
international
Climate change
Online Access:https://pure.knaw.nl/portal/en/publications/c785fa50-1d96-4aa0-beac-125ee92f32b5
https://doi.org/10.1016/j.envres.2016.07.021
https://hdl.handle.net/20.500.11755/c785fa50-1d96-4aa0-beac-125ee92f32b5
Description
Summary: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.

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