Quantifying wet and dry atmospheric inputs of mercury to Manitoba Hydro reservoirs and watersheds

由于单位能源温室气体排放量较低，水力发电目前被吹捧为相对“绿色”。然而，水库建设还有许多其他环境影响，包括甲基汞(甲基汞；汞的一种有毒形式)在鱼类中的产生和生物积累。为了准确量化水库建设对汞生物地球化学循环的净影响，研究人员需要测量完整森林流域的大气汞负荷，并了解这些输入在洪水后如何变化。这些甲基汞和无机汞(II)的大气输入可以从水库输出的甲基汞和汞(II)中减去，以确定例如水库本身的甲基汞净生产量。我们建议的总体目标是量化进入马尼托巴省水库和流域的甲基汞和汞(II)的干湿大气输入。这将通过在马尼托巴省水力发电站启动湿沉积汞监测计划来实现，该计划将与在安大略省西北部实验湖地区收集的长期和不断扩大的湿沉积和干沉积数据集一起使用。我们的研究将使Manitoba Hydro能够更准确地量化和预测水库创建对汞的生物地球化学循环和鱼类中甲基汞的生物积累的净影响。这些信息还将使马尼托巴省水电公司能够准确地将其单位发电量的净汞“足迹”与北美燃煤发电的单位发电量进行比较，从而更好地解释水电生产的环境效益。我们的数据集还将有助于正在进行的研究，检查从马尼托巴省水电流域到哈德逊湾的汞净出口，在哈德逊湾，某些种类的海洋哺乳动物含有足够高的汞浓度，足以引起将其作为传统食物来源的原住民的关注。最后，我们建议的研究将通过新启动的加拿大环境部清洁空气监管议程(CARA)汞科学计划，帮助我们全面了解加拿大各地的汞沉积。

Hydroelectricity is currently touted as relatively "green" due to its low per unit energy greenhouse gas emissions. However, reservoir creation has many other environmental impacts, including the production and bioaccumulation of methylmercury (MeHg; a toxic form of Hg) into fish. To accurately quantify the net effect of reservoir creation on the biogeochemical cycling of Hg, researchers require measures of atmospheric loadings of Hg to intact forested watersheds, and an understanding of how these inputs change following flooding. These atmospheric inputs of MeHg and inorganic Hg(II) can then be subtracted from exports of MeHg and Hg(II) from reservoirs to determine, for example, the net production of MeHg within the reservoir itself. The overall objective of our proposal is to quantify wet and dry atmospheric inputs of MeHg and Hg(II) to Manitoba Hydro reservoirs and watersheds. This will be accomplished by initiating a wet deposition Hg monitoring program at a Manitoba Hydro generating station to be used in conjunction with a long-term and expanding dataset of wet and dry deposition being collected at the Experimental Lakes Area in northwestern Ontario. Our research will allow Manitoba Hydro to more accurately quantify and predicatively model the net impact of reservoir creation on the biogeochemical cycling of Hg and the bioaccumulation of MeHg in fish. Such information will also allow Manitoba Hydro to accurately compare its net Hg "footprint" per unit energy produced relative to that associated with burning coal in North America to produce an equivalent amount of electricity, and better explain the environmental benefits of hydroelectricity production. Our dataset will also contribute to ongoing studies examining the net export of Hg from Manitoba Hydro watersheds to Hudson Bay, where certain species of marine mammals contain high enough concentrations of Hg to be of concern to First Nations peoples using them as a traditional food source. Finally, our proposed research will contribute via the newly initiated Environment Canada Clean Air Regulatory Agenda (CARA) Mercury Science Program to our overall understanding of Hg deposition across Canada.