Transthyretin-Binding Activity of Contaminants in Blood from Polar Bear (Ursus maritimus) Cubs

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• 作者：Jenny Bytingsvik ; Eszter Simon ; Pim E. G. Leonards ; Marja Lamoree ; Elisabeth Lie ; Jon Aars ; Andrew E. Derocher ; 脴ystein Wiig ; Bj酶rn M. Jenssen ; Timo Hamers
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：May 7, 2013
• 年：2013
• 卷：47
• 期：9
• 页码：4778-4786
• 全文大小：431K
• 年卷期：v.47,no.9(May 7, 2013)
• ISSN：1520-5851

文摘

We determined the transthyretin (TTR)-binding activity of blood-accumulating contaminants in blood plasma samples of approximately 4-months-old polar bear (Ursus maritimus) cubs from Svalbard sampled in 1998 and 2008. The TTR-binding activity was measured as thyroxine (T4)-like equivalents (T4-EQ_Meas). Our findings show that the TTR-binding activity related to contaminant levels was significantly lower (45%) in 2008 than in 1998 (mean 卤 standard error of mean: 1998, 2265 卤 231 nM; 2008, 1258 卤 170 nM). Although we cannot exclude a potential influence of between-year differences in capture location and cub body mass, our findings most likely reflect reductions of TTR-binding contaminants or their precursors in the arctic environment (e.g., polychlorinated biphenyls [PCBs]). The measured TTR-binding activity correlated positively with the cubs鈥?plasma levels of hydroxylated PCBs (OH-PCBs). No such association was found between TTR-binding activity and the plasma levels of perfluoroalkyl substances (PFASs). The OH-PCBs explained 60 卤 7% and 54 卤 4% of the TTR-binding activity in 1998 and 2008, respectively, and PFASs explained 鈮?.2% both years. Still, almost half the TTR-binding activity could not be explained by the contaminants we examined. The considerable levels of TTR-binding contaminants warrant further effect directed analysis (EDA) to identify the contaminants responsible for the unexplained part of the observed TTR-binding activity.