Environment Canada, National Wildlife Research Centre, Carleton University, Raven Road, Ottawa, Ontario, Canada K1A 0H3.
Environment Canada, National Wildlife Research Centre, Carleton University, Raven Road, Ottawa, Ontario, Canada K1A 0H3.
Sci Total Environ. 2015 Mar 15;509-510:67-90. doi: 10.1016/j.scitotenv.2014.05.133. Epub 2014 Jun 19.
This review summarizes data and information which have been generated on mercury (Hg) in the marine environment of the Canadian Arctic since the previous Canadian Arctic Contaminants Assessment Report (CACAR) was released in 2003. Much new information has been collected on Hg concentrations in marine water, snow and ice in the Canadian Arctic. The first measurements of methylation rates in Arctic seawater indicate that the water column is an important site for Hg methylation. Arctic marine waters were also found to be a substantial source of gaseous Hg to the atmosphere during the ice-free season. High Hg concentrations have been found in marine snow as a result of deposition following atmospheric mercury depletion events, although much of this Hg is photoreduced and re-emitted back to the atmosphere. The most extensive sampling of marine sediments in the Canadian Arctic was carried out in Hudson Bay where sediment total Hg (THg) concentrations were low compared with other marine regions in the circumpolar Arctic. Mass balance models have been developed to provide quantitative estimates of THg fluxes into and out of the Arctic Ocean and Hudson Bay. Several recent studies on Hg biomagnification have improved our understanding of trophic transfer of Hg through marine food webs. Over the past several decades, Hg concentrations have increased in some marine biota, while other populations showed no temporal change. Marine biota also exhibited considerable geographic variation in Hg concentrations with ringed seals, beluga and polar bears from the Beaufort Sea region having higher Hg concentrations compared with other parts of the Canadian Arctic. The drivers of these variable patterns of Hg bioaccumulation, both regionally and temporally, within the Canadian Arctic remain unclear. Further research is needed to identify the underlying processes including the interplay between biogeochemical and food web processes and climate change.
本综述总结了自 2003 年发布上次加拿大北极污染物评估报告 (CACAR) 以来，在加拿大北极海洋环境中生成的关于汞 (Hg) 的数据和信息。已经收集了大量关于加拿大北极海洋水中、雪和冰中 Hg 浓度的新信息。对北极海水中甲基化速率的首次测量表明，水柱是 Hg 甲基化的重要场所。在无冰季节，北极海洋水也是大气中气态 Hg 的重要来源。由于大气汞消耗事件后沉积，海洋雪中发现了高浓度的 Hg，但其中大部分 Hg 被光还原并重新释放回大气中。在哈德逊湾进行了加拿大北极地区最广泛的海洋沉积物采样，与环极北极地区的其他海洋区域相比，哈德逊湾的沉积物总汞 (THg) 浓度较低。已经开发了质量平衡模型，以提供 THg 通量进出北极海洋和哈德逊湾的定量估计。最近关于 Hg 生物放大的几项研究提高了我们对通过海洋食物网转移 Hg 的营养转移的理解。在过去几十年中，一些海洋生物群的 Hg 浓度增加，而其他种群没有时间变化。海洋生物群的 Hg 浓度也表现出相当大的地理变化，与来自波弗特海地区的环斑海豹、白鲸和北极熊相比，加拿大北极地区的其他地区的 Hg 浓度更高。这些 Hg 生物累积的区域和时间变化模式的驱动因素在加拿大北极地区仍不清楚。需要进一步研究以确定潜在的过程，包括生物地球化学和食物网过程以及气候变化之间的相互作用。
