气候变化领域集成服务门户

Temporal trends of persistent organic pollutants (POPs: PCBs, OH-PCBs, p,p'-DDE, HCB, beta-HCH, oxychlordane, BDE-47, and 153) in relation to changes in feeding habits and body condition in adult female polar bears (Ursus maritimus) from the Barents Sea subpopulation were examined over 20 years (1997-2017). All 306 samples were collected in the spring (April). Both stable isotope values of nitrogen (delta N-15) and carbon (delta C-13) from red blood cells declined over time, with a steeper trend for delta C-13 between 2012 and 2017, indicating a decreasing intake of marine and high trophic level prey items. Body condition, based on morphometric measurements, had a nonsignificant decreasing tendency between 1997 and 2005, and increased significantly between 2005 and 2017. Plasma concentrations of BDE-153 and beta-HCH did not significantly change over time, whereas concentrations of Sigma 4PCB, Sigma 5OH-PCB, BDE-47, and oxychlordane declined linearly. of p,p'-DDE and HCB, however, declined until 2012 and 2009, respectively, and increased thereafter. Changes in feeding habits and body condition did not significantly affect POP trends. The study indicates that changes in diet and body condition were not the primary driver of POPs in polar bears, but were controlled in large part by primary and/or secondary emissions of POPs.