Water Research Center, King Abdulaziz University (KAU), Post Box 80200, Jeddah, 21598, Saudi Arabia.
Water Technology Center, IARI, New Delhi, 110012, India.
Environ Sci Pollut Res Int. 2017 Sep;24(26):21459-21475. doi: 10.1007/s11356-017-9704-z. Epub 2017 Jul 26.
Groundwater samples were collected from 44 wells in the Ramganga Sub-Basin (RSB), India, and analysed for major ions, nutrients and trace metals. The primary goal of this study is to evaluate the hydrochemistry and to identify the geochemical processes that govern the water chemistry in the shallow and deep tube wells in the study area using geochemical methods. The knowledge of changes in hydrochemistry of the aquifers is important for both groundwater recharge and use in the region. This study found that there are substantial differences of water chemistry between shallow and deep wells. In the shallow wells, the average concentrations of total dissolved solid (TDS), Na, K, Ca, Mg, HCO, Cl, SO, NO, PO, F, Cu, Mn, Fe and Cr are twofold higher than the deep wells. The concentrations of dissolved silica in the groundwater do not vary with the depth, which implies that the variation in the water chemistry is not due to mineral dissolution alone. Major ion ratios and saturation indices suggest that the water chemistry is predominantly controlled by dissolution of carbonate minerals, silicate weathering and ion exchange reactions. Thermodynamic evaluation (ion activity ratios and stability filed diagrams) indicates that the kaolinite and gibbsite controlled the water chemistry in the both shallow and deep wells. In addition, the groundwater chemistry in the shallow wells is affected by the vertical infiltration of contaminated water from surface contamination sources and nitrification process. In the deep wells, absence of NO and low concentrations of Cl, SO, PO and F imply the role of regional flow and denitrification in the groundwater. Results concluded that proper management plan is necessary to protect the shallow aquifer in the RSB since shallow aquifer pumping is less expensive than the deeper one.
从印度拉姆根加子流域（RSB）的 44 口井中采集地下水样本，并分析主要离子、营养物质和痕量金属。本研究的主要目的是评估水化学，并使用地球化学方法识别控制研究区浅层和深层管井中水质的地球化学过程。了解含水层水化学的变化对于该地区的地下水补给和利用都很重要。本研究发现，浅层和深层水井的水质存在显著差异。在浅层水井中，总溶解固体（TDS）、Na、K、Ca、Mg、HCO、Cl、SO、NO、PO、F、Cu、Mn 和 Fe 的平均浓度是深层水井的两倍。地下水中溶解硅的浓度与深度无关，这意味着水化学的变化不是仅仅由于矿物溶解引起的。主要离子比值和饱和度指数表明，水化学主要受碳酸盐矿物溶解、硅酸盐风化和离子交换反应的控制。热力学评估（离子活度比和稳定场图）表明，高岭石和水铝石控制了浅层和深层水井的水化学。此外，浅层水井中的地下水化学受到地表污染来源的垂直渗透污染水和硝化作用的影响。在深层水井中，NO 的缺乏和 Cl、SO、PO 和 F 的低浓度表明了区域流动和地下水反硝化作用的作用。研究结果表明，由于浅层含水层的抽水量比深层含水层便宜，因此需要制定适当的管理计划来保护 RSB 的浅层含水层。
