| Abstract
| - We hypothesized that depleted fat reserves in grizzlybears (Ursus arctos horribilis) following annual hibernationwould reveal increases in persistent organic pollutant(POP) concentrations compared to those present in thefall. We obtained fat and hair from British Columbia grizzlybears in early spring 2004 to compare with those collectedin fall 2003, with the two tissue types providing contaminantand dietary information, respectively. By correcting for theindividual feeding habits of grizzlies using a stable isotope-based approach, we found that polychlorinated biphenyls(ΣPCBs) increased by 2.21×, polybrominated diphenylethers(ΣPBDEs) increased by 1.58×, and chlordanes (ΣCHL) by1.49× in fat following hibernation. Interestingly, individualPOPs elicited a wide range of hibernation-associatedconcentration effects (e.g., CB-153, 2.25× vs CB-169, 0.00×),resulting in POP pattern convergence in a PCA model oftwo distinct fall feeding groups (salmon-eating vs non-salmon-eating) into a single spring (post-hibernation) group. Ourresults suggest that diet dictates contaminant patterns duringa feeding phase, while metabolism drives patternsduring a fasting phase. This work suggests a duality of POP-associated health risks to hibernating grizzly bears: (1)increased concentrations of some POPs during hibernation;and (2) a potentially prolonged accumulation of water-soluble, highly reactive POP metabolites, since grizzly bearsdo not excrete during hibernation.
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