Environment Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON K1A 0H3, Canada.
Environment Canada, National Wildlife Research Centre, Carleton University, Ottawa, ON K1A 0H3, Canada.
Sci Total Environ. 2015 Mar 15;509-510:91-103. doi: 10.1016/j.scitotenv.2014.05.142. Epub 2014 Jun 14.
This review summarizes our current state of knowledge regarding the potential biological effects of mercury (Hg) exposure on fish and wildlife in the Canadian Arctic. Although Hg in most freshwater fish from northern Canada was not sufficiently elevated to be of concern, a few lakes in the Northwest Territories and Nunavut contained fish of certain species (e.g. northern pike, Arctic char) whose muscle Hg concentrations exceeded an estimated threshold range (0.5-1.0 μg g(-1) wet weight) within which adverse biological effects begin to occur. Marine fish species generally had substantially lower Hg concentrations than freshwater fish; but the Greenland shark, a long-lived predatory species, had mean muscle Hg concentrations exceeding the threshold range for possible effects on health or reproduction. An examination of recent egg Hg concentrations for marine birds from the Canadian Arctic indicated that mean Hg concentration in ivory gulls from Seymour Island fell within the threshold range associated with adverse effects on reproduction in birds. Mercury concentrations in brain tissue of beluga whales and polar bears were generally lower than levels associated with neurotoxicity in mammals, but were sometimes high enough to cause subtle neurochemical changes that can precede overt neurotoxicity. Harbour seals from western Hudson Bay had elevated mean liver Hg concentrations along with comparatively high muscle Hg concentrations indicating potential health effects from methylmercury (MeHg) exposure on this subpopulation. Because current information is generally insufficient to determine with confidence whether Hg exposure is impacting the health of specific fish or wildlife populations in the Canadian Arctic, biological effects studies should comprise a major focus of future Hg research in the Canadian Arctic. Additionally, studies on cellular interactions between Hg and selenium (Se) are required to better account for potential protective effects of Se on Hg toxicity, especially in large predatory Arctic fish, birds, and mammals.
这篇综述总结了我们目前对于汞（Hg）暴露对加拿大北极地区鱼类和野生动物潜在生物学影响的认识。尽管加拿大北部大多数淡水鱼中的 Hg 含量没有高到令人担忧的程度，但西北地区和努纳武特地区的一些湖泊中，某些鱼类（如北方梭鲈、北极茴鱼）的肌肉 Hg 浓度超过了估计的阈值范围（0.5-1.0μg g(-1)湿重），在此范围内，不良的生物学效应开始出现。海洋鱼类的 Hg 浓度通常低于淡水鱼类，但格陵兰鲨鱼是一种长寿的掠食性物种，其肌肉 Hg 浓度超过了可能对健康或生殖产生影响的阈值范围。对加拿大北极地区海洋鸟类最近的卵 Hg 浓度的检查表明，西摩岛象牙鸥的平均 Hg 浓度落在与鸟类生殖不良影响相关的阈值范围内。白鲸和北极熊脑组织中的 Hg 浓度通常低于与哺乳动物神经毒性相关的水平，但有时也足够高，导致潜在的神经化学变化，这些变化可能先于明显的神经毒性。哈德逊湾西部的港湾海豹的肝脏 Hg 浓度平均值较高，肌肉 Hg 浓度也相对较高，表明该亚群可能因甲基汞（MeHg）暴露而对健康产生影响。由于目前的信息通常不足以有把握地确定 Hg 暴露是否正在影响加拿大北极地区特定鱼类或野生动物种群的健康，因此生物效应研究应该成为加拿大北极地区未来 Hg 研究的主要重点。此外，还需要研究 Hg 与硒（Se）之间的细胞相互作用，以更好地说明 Se 对 Hg 毒性的潜在保护作用，特别是在大型北极掠食性鱼类、鸟类和哺乳动物中。
