Department of Biology, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
St. Lawrence River Institute of Environmental Sciences, Cornwall, Ontario K6H 4Z1, Canada.
Sci Total Environ. 2014 Dec 1;500-501:131-8. doi: 10.1016/j.scitotenv.2014.08.080. Epub 2014 Sep 15.
A dynamic mass balance model was developed for the St. Lawrence River near Cornwall, Ontario that predicts and hindcasts mercury concentrations and fluxes in three forms, elemental Hg (Hg(0)), divalent mercury (Hg(2+)), and methyl mercury (MeHg), in a six compartment environment (air, water, porewater, sediment, periphyton, and benthic invertebrates). Our objective was to construct a dynamic mass balance model for mercury in the St. Lawrence River near Cornwall, Ontario based on the framework and results of a steady-state mass balance model developed previously for this site. The second objective was to estimate industrial mercury emissions based on mercury residues deposited in sediments prior to 1970, the year when regulations were implemented to reduce mercury pollution in the environment. We compiled mercury concentrations, fluxes, and transformation rates from previous studies completed in this section of the river (area of approximately 100km(2)) to develop the model. Estimated mercury concentrations in all media were similar to measured data (R(2)=0.99), with only minor exceptions, providing a satisfactory overall description of the mercury loadings and transformation rates of the different mercury species. The estimated historical emissions prior to 1970 from local industries along the Cornwall waterfront were approximately 400kgyear(-1). A storm sewer discharge of 5000m(3)/day resulted in a significant increase in mercury concentrations, particularly in sediment (617ngg(-1) to 624ngg(-1); p=0.004). Model results suggest that discharges of mercury from sources such as local industries and storm sewers have an impact on mercury in media such as sediment and water. This model should provide a basis for predicting and hindcasting mercury concentrations in other river environments as well, because it considers three distinct forms of mercury, and contains environmental media common to all rivers, including some (e.g. periphyton) not typically included in previous mercury models.
我们开发了一个动态质量平衡模型，用于安大略省康沃尔附近的圣劳伦斯河，该模型预测和回溯三种形态的汞浓度和通量，即元素汞（Hg(0)）、二价汞（Hg(2+)）和甲基汞（MeHg），在一个六分区环境（空气、水、孔隙水、沉积物、周丛生物和底栖无脊椎动物）中。我们的目标是基于先前为该地点开发的稳态质量平衡模型的框架和结果，为安大略省康沃尔附近的圣劳伦斯河建立一个汞的动态质量平衡模型。第二个目标是根据 1970 年以前沉积在沉积物中的汞残留物来估计工业汞排放量，1970 年实施了减少环境汞污染的法规。我们从该河流段（面积约 100km(2))先前完成的研究中汇编了汞浓度、通量和转化速率，以开发模型。所有介质中的估计汞浓度与测量数据相似（R(2)=0.99)，只有少数例外，总体上对不同汞物种的汞负荷和转化速率进行了满意的描述。1970 年以前当地工业沿康沃尔滨水区的历史排放量估计约为 400kgyear(-1)。每天 5000m(3)/天的雨水下水道排放导致汞浓度显著增加，特别是在沉积物中（617ngg(-1)至 624ngg(-1)；p=0.004)。模型结果表明，来自当地工业和雨水下水道等来源的汞排放对沉积物和水等介质中的汞有影响。由于该模型考虑了三种不同形态的汞，并且包含了所有河流共有的环境介质，包括一些（例如周丛生物）以前的汞模型中通常不包括的介质，因此该模型应该为预测和回溯其他河流环境中的汞浓度提供基础。
