Kumar Manish, Das Aparna, Das Nilotpal, Goswami Ritusmita, Singh Umesh Kumar
Department of Environmental Science, Tezpur University, Napaam, 784-028 Assam, India.
Department of Environmental Science, Tezpur University, Napaam, 784-028 Assam, India.
Chemosphere. 2016 May;150:227-238. doi: 10.1016/j.chemosphere.2016.02.019. Epub 2016 Feb 21.
Considerable lacunae exists in As and F(-) co-contamination investigation in the Brahmaputra and Gangetic floodplains. Therefore we selected Diphu a township in the Karbi Plateau rising from the Brahmaputra floodplains for evaluation of As and F co-occurrence, correlation with coexisting ions of the aquifer system and elucidation of potential processes for releasing As and F(-) in the groundwater. Our initial appraisal used generic plots for identification of hydro geochemical processes and major water types. Subsequently, As and F(-) co-occurrence with pH, depth, HCO3(-), SO4(2-), Ca(2+) and Fe were probed for possible correlation followed by hierarchical cluster analyses to identify key processes for co-occurrence. Finally, saturation indices of groundwater minerals were calculated using MINTEQA2 to elucidate prospective As and F(-) release into groundwater. Results indicate F(-) and As presence in Ca-HCO3 rich water along with positive correlation between Ca(2+) and F(-) possibly due to limestone reserves in adjoining areas. Multivariate analyses suggest the presence of high concentrations of PO4(3-), and H4SiO4 either individually or in combination can enhance the mobility of both As and F(-) and possibly abet conditions conducive for co-contamination of aquifers. Initial release of As and F(-) from the parent rock seems driven by the anthropogenic activities while mobilization depends on chemical interactions and individual affinities of the elements. The results of speciation highlight further mobilization of As and F(-) into the groundwater which in turn require regular attention for sustainable management of scarce water resource present in the area.
在雅鲁藏布江和恒河泛滥平原的砷和氟共污染调查中存在相当大的空白。因此，我们选择了位于雅鲁藏布江泛滥平原上的卡尔比高原的迪普胡镇，以评估砷和氟的共存情况、与含水层系统共存离子的相关性，并阐明地下水中砷和氟释放的潜在过程。我们最初的评估使用了通用图表来识别水文地球化学过程和主要水型。随后，探究了砷和氟与pH值、深度、碳酸氢根离子、硫酸根离子、钙离子和铁的共存情况，以寻找可能的相关性，接着进行层次聚类分析以确定共存的关键过程。最后，使用MINTEQA2计算地下水矿物质的饱和指数，以阐明砷和氟向地下水中释放的可能性。结果表明，在富含钙-碳酸氢根的水中存在氟和砷，并且钙离子和氟之间呈正相关，这可能是由于相邻地区存在石灰岩储量。多变量分析表明，高浓度的磷酸根离子和硅酸单独或联合存在时，都可以提高砷和氟的迁移率，并可能助长有利于含水层共同污染的条件。母岩中砷和氟的初始释放似乎是由人为活动驱动的，而迁移则取决于元素的化学相互作用和个体亲和力。形态分析结果突出了砷和氟进一步向地下水中的迁移，这反过来需要对该地区稀缺水资源的可持续管理给予定期关注。
