College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, 266590, China.
College of Energy and Mining Engineering, Shandong University of Science and Technology, Qingdao, 266590, China.
Environ Geochem Health. 2022 Mar;44(3):961-977. doi: 10.1007/s10653-021-01011-z. Epub 2021 Jun 15.
In this study, the formation mechanism and water quality of groundwater in the northwest of Nansi Lake Catchment (NNLC) were analyzed through mathematical statistics, hydrochemical analysis and entropy weighted water quality index (EWQI), and the human health risk of nitrate was also evaluated. To this end, 89 wells in the NNLC were sampled, and the groundwater samples were divided into three groups (I, II, and III) according to cluster analysis results and spatial distribution. The main results are as follows: Topographically, Groups I, II, and III correspond to the alluvial plains, apron plain, and low hills and its front margin, respectively. According to the Piper diagram, the hydrochemical types of Groups I and II groundwater are Na-SO·Cl and Ca·Mg-HCO, respectively, and that of Group III is more concentrated, mostly corresponding to the Ca-HCO type. Hydrochemical analysis indicated that the development of groundwater hydrochemistry is mainly attributable to water-rock interactions, with the primary process being the dissolution of minerals such as calcite, dolomite, gypsum, and albite. Evaporation exhibited an increasing trend from the northeast to the southwest. Groups I and III presented obvious effects of human activities, with Group I showing sulfate pollution and Group III mainly showing nitrate pollution. Analysis of the characteristics and causes of the groundwater hydrochemistry revealed the proposed approach has excellent performance for classification in areas with complex hydrogeological conditions. The results of EWQI showed that the overall water quality was good, following the order Group III > Group II > Group I. The overall human health risk of nitrate in groundwater was low, but the risk was slightly higher for children than for adults. Therefore, the effects of nitrate contamination should be considered when exploiting hilly and peri-urban groundwater for drinking water.
本研究通过数理统计、水化学分析和熵权水质指数（EWQI），分析了南四湖流域西北部地下水的形成机制和水质，并评价了硝酸盐的人体健康风险。为此，采集了南四湖流域 89 口井的地下水样本，根据聚类分析结果和空间分布，将地下水样本分为三组（I、II 和 III）。主要结果如下：地形上，I、II 和 III 组分别对应于冲积平原、裙状平原和低山及其前缘。根据 Piper 图，I 组和 II 组地下水的水化学类型分别为 Na-SO·Cl 和 Ca·Mg-HCO，III 组则更为集中，主要对应于 Ca-HCO 型。水化学分析表明，地下水水化学的发展主要归因于水岩相互作用，主要过程是方解石、白云石、石膏和钠长石等矿物的溶解。蒸发作用从东北向西南呈增加趋势。I 组和 III 组表现出明显的人为活动影响，I 组表现出硫酸盐污染，III 组主要表现出硝酸盐污染。地下水水化学特征和成因分析表明，该方法在水文地质条件复杂的地区具有良好的分类效果。EWQI 分析结果表明，整体水质良好，顺序为 III 组>II 组>I 组。地下水硝酸盐的整体人体健康风险较低，但儿童的风险略高于成人。因此，在开采丘陵和城郊地区地下水作为饮用水时，应考虑硝酸盐污染的影响。
