Christensen Jennie R, MacDuffee Misty, Yunker Mark B, Ross Peter S
Institute of Ocean Sciences, Fisheries and Oceans Canada, Sidney, British Columbia V8L 4B2, Canada.
Environ Sci Technol. 2007 Mar 15;41(6):1834-40. doi: 10.1021/es0626335.
We hypothesized that depleted fat reserves in grizzly bears (Ursus arctos horribilis) following annual hibernation would reveal increases in persistent organic pollutant (POP) concentrations compared to those present in the fall. We obtained fat and hair from British Columbia grizzly bears in early spring 2004 to compare with those collected in fall 2003, with the two tissue types providing contaminant and dietary information, respectively. By correcting for the individual feeding habits of grizzlies using a stable isotope-based approach, we found that polychlorinated biphenyls (sigmaPCBs) increased by 2.21x, polybrominated diphenylethers (sigmaPBDEs) increased by 1.58x, and chlordanes (sigmaCHL) by 1.49x in fat following hibernation. Interestingly, individual POPs elicited a wide range of hibernation-associated concentration effects (e.g., CB-153, 2.25x vs CB-169, 0.00x), resulting in POP pattern convergence in a PCA model of two distinct fall feeding groups (salmon-eating vs non-salmon-eating) into a single spring (post-hibernation) group. Our results suggest that diet dictates contaminant patterns during a feeding phase, while metabolism drives patterns during 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 bears do not excrete during hibernation.
我们假设，与秋季相比，灰熊（棕熊）每年冬眠后脂肪储备减少，会导致持久性有机污染物（POP）浓度增加。2004年早春，我们从不列颠哥伦比亚省的灰熊身上获取了脂肪和毛发样本，与2003年秋季采集的样本进行比较，这两种组织类型分别提供了污染物和饮食信息。通过使用基于稳定同位素的方法校正灰熊的个体饮食习惯，我们发现冬眠后脂肪中的多氯联苯（ΣPCBs）增加了2.21倍，多溴二苯醚（ΣPBDEs）增加了1.58倍，氯丹（ΣCHL）增加了1.49倍。有趣的是，个体POPs引发了一系列与冬眠相关的浓度效应（例如，CB - 153增加2.25倍，而CB - 169增加0倍），导致在主成分分析模型中，两个不同秋季摄食组（食鲑鱼组与非食鲑鱼组）的POP模式在春季（冬眠后）合并为一个单一的组。我们的结果表明，饮食决定摄食阶段的污染物模式，而新陈代谢则驱动禁食阶段的模式。这项研究表明，POP对冬眠灰熊的健康风险具有双重性：（1）冬眠期间某些POPs浓度增加；（2）由于灰熊在冬眠期间不排泄，水溶性、高反应性POP代谢物可能会长期积累。
