The main objective of the study is to evaluate the hydrogeochemical processes and potential health risk assessment for humans in groundwater of Maputaland coastal aquifer, South Africa. In this study, 53 and 42 groundwater samples were collected from bore wells during 2018 and 2019 and were analysed for major ions, minor ions, nutrients and trace metals. Na–Cl water type was dominant in groundwater followed by Ca–HCO₃. Cross plots revealed that ion exchange, reverse ion exchange, silicate weathering, seawater mixing and anthropogenic inputs from agricultural activities govern the groundwater chemistry. GIS methods were adopted to produce spatial distribution maps of major ions through which locations of groundwater contamination and the intensity of hydrogeochemical processes were identified. Mean concentration of trace metals were in the order: Zn > Li > Al > Fe > Mn > Cu > Pb > As > Co > Cd in 2018, Fe > Zn > Mn > Sr > B > Pb > Cu > Co > Cr > Cd > Ag > Al > Ni in 2019. Most of the trace metals were found to be within the WHO standards for drinking water except Cd, Zn, Pb, Mn, Al and Fe. Health risk assessment of trace metals in groundwater via ingestion and dermal absorption pathways were carried out. Hazard Quotients (HQs) and Hazard Index (HI) of all trace metals were below 1, except HQ_ingestion and HI for Co and Pb which were greater than 1 in children. This suggests that these metals pose adverse risks to local people, and children were more sensitive to risks than adults. HI values for adults and children were medium indicating high risk. This is the first baseline study conducted in the study area which identifies the chemical characterization and the potential health risk due to trace metals contamination.

中文翻译：

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地下水中的水文地球化学过程和微量金属污染：对南非马普塔兰沿海含水层中人类健康的影响

这项研究的主要目的是评估南非Maputaland沿海含水层中地下水的水文地球化学过程和对人类的潜在健康风险评估。在这项研究中，在2018年和2019年从钻孔中收集了53和42个地下水样本，并对其中的主要离子，次要离子，养分和微量金属进行了分析。Na–Cl水类型在地下水中占主导地位，其次是Ca–HCO ₃。交叉图显示，离子交换，反向离子交换，硅酸盐风化，海水混合和农业活动的人为输入控制着地下水的化学作用。采用GIS方法生成主要离子的空间分布图，通过该图可以确定地下水污染的位置和水文地球化学过程的强度。痕量金属的平均浓度依次为：2018年Zn> Li> Al> Fe> Mn> Cu> Pb> As> Co> Cd，Fe> Zn> Mn> Sr> B> Pb> Cu> Co> Cr> Cd> Ag> Al>Ni。2019年，发现大多数痕量金属均在WHO饮用水标准之内，但Cd，Zn，Pb，Mn，Al和Fe除外。通过摄入和皮肤吸收途径对地下水中的痕量金属进行健康风险评估。除HQ外，所有痕量金属的危害商（HQs）和危害指数（HI）均低于1儿童的Co和Pb_摄入和HI大于1。这表明这些金属对当地居民构成了不利风险，儿童对风险的敏感性比成人高。成人和儿童的HI值处于中等水平，表明高风险。这是在研究区域进行的第一项基线研究，该研究确定了由于痕量金属污染而引起的化学特性和潜在的健康风险。