Department of Biological Sciences, University of Alberta , Edmonton, Alberta T6G 2E9, Canada.
Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, University of Alberta , CW405, Biological Sciences Building, Edmonton, AB T6G 2E9, Canada.
Environ Sci Technol. 2016 May 17;50(10):5313-9. doi: 10.1021/acs.est.6b00483. Epub 2016 Apr 29.
Methylmercury is one of the more toxic forms of mercury (Hg), the biomagnification of which is prevalent in the Arctic where apex predators such as polar bears (Ursus maritimus) can carry high loads. The maternal transfer of contaminants to offspring is a concern, as offspring may be particularly sensitive to the effects of environmental pollutants during early development. However, few studies of polar bears report on Hg in dependent young. We examined hair total Hg (THg) concentrations in 24 polar bear family groups in western Hudson Bay: mother, cub-of-the-year (COY), yearling, and 2 year old. THg concentrations increased with bear age, with COYs having lower concentrations than other offspring groups (p ≤ 0.008). Using AICc-based regression models, we found maternal THg to be positively related to body condition and litter size, while overall offspring THg was positively related to maternal body condition in addition to being dependent on the sex and age of the offspring. COY THg concentrations were positively related to maternal THg while also depending on the sex of the offspring. Considering our results, future studies in polar bear ecotoxicology are encouraged to include offspring of different ages and sexes.
甲基汞是汞（Hg）的毒性更强的形态之一，在北极地区，汞的生物放大作用很普遍，那里的顶级捕食者如北极熊（Ursus maritimus）体内可能携带高浓度的汞。污染物通过母体向后代转移是一个令人担忧的问题，因为在早期发育过程中，后代可能特别容易受到环境污染物的影响。然而，很少有关于北极熊幼崽体内汞含量的研究报告。我们研究了哈德逊湾西部 24 个北极熊家庭群体的毛发总汞（THg）浓度：母熊、当年幼崽（COY）、一岁幼崽和两岁幼崽。THg 浓度随熊的年龄增长而增加，COY 的浓度低于其他后代群体（p≤0.008）。使用基于 AICc 的回归模型，我们发现母体 THg 与身体状况和产仔数呈正相关，而总体后代 THg 除了依赖于后代的性别和年龄外，还与母体身体状况呈正相关。COY 的 THg 浓度与母体 THg 呈正相关，同时也取决于后代的性别。考虑到我们的结果，鼓励未来在北极熊生态毒理学方面的研究纳入不同年龄和性别的后代。
