College of Water Sciences, Beijing Normal University, Beijing 100875, China; College of Environment and Resources, Jilin University, Changchun 130021, China.
College of Environment and Resources, Jilin University, Changchun 130021, China.
J Environ Manage. 2015 Apr 1;152:109-19. doi: 10.1016/j.jenvman.2015.01.027. Epub 2015 Jan 21.
Taking an artificial groundwater recharge site in Shanghai, China as an example, this study employed a combination of laboratory experiment and numerical modeling to investigate the transport and transformation of major solutes, as well as the mechanism of associated water-rock interactions in groundwater during artificial groundwater recharge. The results revealed that: (1) Major ions in groundwater were mainly affected by mixing, ion exchanging (Ca(2+), Mg(2+), Na(+), K(+)), as well as dissolution of Calcite, Dolomite. Dissolution of carbonate minerals was not entirely dependent on the pattern of groundwater recharge, the reactivity of the source water itself as indicated by the sub-saturation with respect to the carbonate minerals is the primary factor. (2) Elemental dissolution of As, Cr and Fe occurred in aquifer was due to the transformation of subsurface environment from anaerobic to aerobic systems. Different to bank filtration recharge or pond recharge, the concentration of Fe near the recharge point was mainly controlled by oxidation dissolution of Siderite, which was followed by a release of As, Cr into groundwater. (3) Field modeling results revealed that the hydro chemical type of groundwater gradually changed from the initial Cl-HCO3-Na type to the Cl-HCO3-Na-Ca type during the recharge process, and its impact radius would reach roughly 800 m in one year. It indicated that the recharge pressure (approx. 0.45 Mpa) would enlarge the impact radius under deep well recharge conditions. According to different recharge modes, longer groundwater resident time will associate with minerals' fully reactions. Although the concentrations of major ions were changing during the artificial recharge process, it did not pose a negative impact on the environmental quality of groundwater. The result of trace elements indicated that controlling the environment factors (especially Eh, DO, flow rate) during the recharge was effective to reduce the potential threats to groundwater quality.
以中国上海的一个人工地下水补给点为例，本研究采用实验室实验和数值模拟相结合的方法，研究了在人工地下水补给过程中主要溶质的运移转化以及与之相关的水岩相互作用机制。结果表明：（1）地下水中的主要离子主要受混合、离子交换（Ca(2+)、Mg(2+)、Na(+)、K(+)）以及方解石、白云石的溶解影响。碳酸盐矿物的溶解并不完全取决于地下水补给的模式，源水本身的反应性，即相对于碳酸盐矿物的亚饱和状态，是主要因素。（2）含水层中方铅矿、铬和铁的元素溶解是由于地下环境从厌氧向需氧系统的转变。与河岸过滤补给或池塘补给不同，补给点附近铁的浓度主要受菱铁矿的氧化溶解控制，随后砷、铬被释放到地下水中。（3）现场模拟结果表明，在补给过程中，地下水的水化学类型逐渐从初始的 Cl-HCO3-Na 型转变为 Cl-HCO3-Na-Ca 型，其影响半径在一年内可达约 800 m。这表明在深井补给条件下，补给压力（约 0.45 MPa）会扩大影响半径。根据不同的补给模式，更长的地下水停留时间将与矿物的充分反应相关联。尽管人工补给过程中主要离子的浓度发生了变化，但这并没有对地下水的环境质量造成负面影响。微量元素的结果表明，在补给过程中控制环境因素（特别是 Eh、DO、流速）是有效降低对地下水质量潜在威胁的方法。
