Depth Stratification Leads to Distinct Zones of Manganese and Arsenic Contaminated Groundwater
Depth Stratification Leads to Distinct Zones of Manganese and Arsenic Contaminated Groundwater
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DOI：
10.1021/acs.est.7b01121
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发表时间：
2017-08-15
影响因子：
11.4
通讯作者：
Fendorf, Scott
中科院分区：
文献类型：
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作者：
Ying, Samantha C.;Schaefer, Michael V.;Fendorf, Scott
提供安全饮用水是一项全球性挑战，世界各地越来越多地使用地下水。然而，地质污染物限制了地下水在大多数大陆的大片地理区域内用于家庭目的的适用性。地下水中的地质污染物通常单独评估，但在这里，我们证明了需要评估多种污染物，以确保地下水是安全的人类消费和农业使用。我们收集了世界上三个含水层区域的地下水化学数据，据报道，这些含水层区域普遍存在砷和锰污染，包括美国的冰川含水层，孟加拉国境内的恒河-雅鲁藏布江-梅赫塔盆地和柬埔寨的湄公河三角洲，沿着中国长江流域的新取样威尔斯井。污染的威尔斯的比例增加了高达40%，在某些情况下，同时考虑As和Mn污染物。Wilcoxon秩和分析表明，在所有地区，锰污染始终发生在比砷污染的威尔斯井明显浅的深度。地下水中的砷浓度预测氧化还原指标（Eh和溶解氧），而锰显示没有显着的关系与任何参数。这些研究结果表明，安全的威尔斯的数量可能会大大高估，在某些地区时，锰污染不考虑和深度可作为一个区分变量，在努力预测区域地下水污染物的存在。
Providing access to safe drinking water is a global challenge, for which groundwater is increasingly being used throughout the world. However, geogenic contaminants limit the suitability of groundwater for domestic purposes over large geographic areas across most continents. Geogenic contaminants in groundwater are often evaluated individually, but here we demonstrate the need to evaluate multiple contaminants to ensure that groundwater is safe for human consumption and agricultural usage. We compiled groundwater chemical data from three aquifer regions across the world that have been reported to have widespread As and Mn contamination including the Glacial Aquifer in the U.S., the Ganges-Brahmaputra-Mehta Basin within Bangladesh, and the Mekong Delta in Cambodia, along with newly sampled wells in the Yangtze River Basin of China. The proportion of contaminated wells increase by up to 40% in some cases when both As and Mn contaminants are considered. Wilcoxon rank-sum analysis indicates that Mn contamination consistently occurs at significantly shallower depths than As contaminated wells in all regions. Arsenic concentrations in groundwater are well predicted by redox indicators (Eh and dissolved oxygen) whereas Mn shows no significant relationship with either parameter. These findings illustrate that the number of safe wells may be drastically overestimated in some regions when Mn contamination is not taken into account and that depth may be used as a distinguishing variable in efforts to predict the presence of groundwater contaminants regionally.