Polischuk S C, Letcher R J, Norstrom R J, Ramsay M A
Department of Biology, University of Saskatchewan, Saskatoon, Canada.
Sci Total Environ. 1995 Jan 15;160-161:465-72. doi: 10.1016/0048-9697(95)04380-j.
We determined concentrations of polychlorinated biphenyls (PCBs), chlordanes (CHLORs), chlorobenzenes (CBzs), hexachlorocyclohexanes (HCHs), and dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDD and DDE) in the tissues of individual polar bears (Ursus maritimus) before and after a lengthy period of fasting. Polar bears are an ideal model for such studies. They undergo one of the most extreme fasts known for any mammal and are located at the top of a long food chain, thus biomagnification of organochlorines (OC) is significant. Adipose tissue and milk were collected from different reproductive classes of adult females (solitary/pregnant, with cubs-of-the-year, with yearling cubs) and were analyzed for organochlorine content. As the fasting period progressed and adipose reserves decreased, concentrations of some organochlorines in the adipose tissue and milk increased on a lipid weight basis. The transfer of contaminants from mothers to offspring thus also increases with duration of the fasting period. This phenomenon could adversely influence the survival and growth of cubs during the critical early phase of their development.
我们测定了在长时间禁食前后，个体北极熊（Ursus maritimus）组织中多氯联苯（PCBs）、氯丹（CHLORs）、氯苯（CBzs）、六氯环己烷（HCHs）、二氯二苯三氯乙烷（DDT）及其代谢物（DDD和DDE）的浓度。北极熊是此类研究的理想模型。它们经历了已知的任何哺乳动物中最极端的禁食之一，且位于长食物链的顶端，因此有机氯（OC）的生物放大作用显著。从成年雌性不同繁殖类别（独居/怀孕、带当年幼崽、带一岁幼崽）收集脂肪组织和乳汁，并分析其有机氯含量。随着禁食期的推进和脂肪储备的减少，脂肪组织和乳汁中某些有机氯的浓度以脂质重量计增加。污染物从母亲向后代的转移也随着禁食期的延长而增加。这种现象可能会在幼崽发育的关键早期阶段对其生存和生长产生不利影响。
