Bone Sharon E, Charette Matthew A, Lamborg Carl H, Gonneea Meagan Eagle
Woods Hole Oceanographic Institution, Department of Marine Chemistry and Geochemistry, Woods Hole, Massachusetts 02543, USA.
Environ Sci Technol. 2007 May 1;41(9):3090-5. doi: 10.1021/es0622453.
We measured the mercury (Hg) in groundwater, aquifer sediments, and surface water in Waquoit Bay (Massachusetts) and found that this toxic metal (range: <3.2-262 pM) was being released within the subterranean estuary, with similarly high levels (range: 18-256 pM) found in the surface waters of the bay. None of the dissolved species (DOC, chloride, and Fe) normally observed to influence Hg partitioning correlated well with the observed Hg concentrations. It was hypothesized that this was in part due to the variable loading in time and space of Hg onto the aquifer sands in combination with the seasonality of groundwater flow through the aquifer. Aquifer sediment samples from the study site ranged from <1 to 12.5 pmol of Hg/g of sediment, suggesting log Kd values on the order of 1. We hypothesize that this was due to the low organic carbon content typical of the aquifer sediments. Last, itwas estimated that submarine groundwater discharge supplied 0.47-1.9 nmol of Hg m(-2) day(-1) to the bay, which is an order of magnitude higher than the atmospheric deposition rate for the northeastern U.S.
我们测量了马萨诸塞州瓦夸特湾地下水中、含水层沉积物和地表水中的汞（Hg），发现这种有毒金属（范围：<3.2 - 262皮摩尔）正在地下河口释放，海湾地表水中也发现了类似的高含量（范围：18 - 256皮摩尔）。通常观察到的影响汞分配的溶解物质（溶解性有机碳、氯化物和铁）与观测到的汞浓度均无良好的相关性。据推测，部分原因是汞在含水层砂层上的时空加载变化，以及地下水通过含水层的季节性流动。研究地点的含水层沉积物样本中汞含量范围为<1至12.5皮摩尔/克沉积物，表明分配系数（Kd）值约为1。我们推测这是由于含水层沉积物中典型的低有机碳含量所致。最后，据估计，海底地下水排放向海湾提供了0.47 - 1.9纳摩尔汞/平方米·天，这比美国东北部的大气沉降速率高一个数量级。
