**1. Introduction**

Groundwater is an indispensable part of human living space and the hydrological cycle, providing high-quality freshwater resources for human beings. It is important for domestic, industrial, and agricultural use globally [1–4]. For drinking purposes, approximately one-third of the world's population rely on groundwater as a water source [5–7]. Especially in arid and semi-arid areas where the precipitation is scarce and the surface water sources are limited, groundwater has become the main water source, or even the only one [2,8]. As the most important water source for human survival, groundwater quality is vital to human health. However, with the continuous population growth and rapid economic development, groundwater pollution has become an urgent problem endangering public health and has put pressure on groundwater resources worldwide [9,10]. For example, studies have shown that 2 types of birth defects and 15 types of cancer may be related to long-term exposure to NO<sup>3</sup> − contaminated groundwater [11–13]. Even at the same groundwater NO<sup>3</sup> − concentration, children and infants have greater health risks than adults, especially infants prone to a disease known as "blue baby syndrome", i.e., methemoglobinemia [14,15]. Fluoride is a major pollutant in groundwater on a global scale as about 260 million people suffer from endemic fluorosis and other diseases due to the intake of high fluoride in groundwater [16,17]. Potentially toxic elements (PTEs) in groundwater can cumulate in the human body throughout almost the human lifespan and cause many diseases, a matter of great concern for the past several years [18–21]. Anthropogenic sources of groundwater pollutants include fertilization, livestock waste, domestic sewage, landfill, metal industry, mining, and other industrial activities. Processes controlling concentrations

**Citation:** Li, J.; Sun, C.; Chen, W.; Zhang, Q.; Zhou, S.; Lin, R.; Wang, Y. Groundwater Quality and Associated Human Health Risk in a Typical Basin of the Eastern Chinese Loess Plateau. *Water* **2022**, *14*, 1371. https://doi.org/10.3390/w14091371

Academic Editors: Jianhua Wu, Peiyue Li and Saurabh Shukla

Received: 25 March 2022 Accepted: 16 April 2022 Published: 22 April 2022

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of physicochemical parameters in groundwater are mainly the mineral dissolution, sorption and desorption processes, ion exchange, reduction and oxidation processes, and chemical weathering [22–26].

Groundwater environment assessment is the basis of sustainable utilization of regional groundwater resources and is of great significance to ecological environment protection. Various scientific approaches have been introduced to assess groundwater quality. Some of these methods include set pair analysis [27], hierarchical analysis [28], matter-element extension analysis [29], fuzzy comprehensive assessment method [2], and water quality index (WQI) [6,8]. The WQI is an efficient tool to access water quality and its suitability for drinking purposes. It was first developed by Horton [30] and since has been widely used in numerous water quality assessment works [31–35]. Varol and Davraz [6] used WQI and multivariate analysis to evaluate groundwater quality and its suitability for drinking and agricultural uses in the Tefenni plain, Turkey. Using an improved water quality index, Zhang et al. [36] considered that groundwater will be affected by the geological environment and human factors during the flow process in Guanzhong Basin, China. In recent years, groundwater quality assessment and spatial analysis based on combining Geographic Information System (GIS) with WQI methods have proven to be a powerful tool for spatial information management of groundwater resources [37–39].

Many scholars have also carried out human health risk assessments (HHRA) to directly and quantitatively reflect the negative health impacts of polluted water on human beings. This method has been widely used in the evaluation of different water bodies, such as rivers [40,41], lakes [42], and wetlands [43], which provide useful insight to ensure human health. For groundwater, Guo et al. [44] found that groundwater arsenic pollution caused by landfill leachate leakage poses unacceptable carcinogenic risks to people of all ages. Farmers continually applying fertilizers during the period between the rainy and dry season leads to the mobilization of NO<sup>3</sup> − and PTEs from cultivated soils to groundwater under favoring geochemical conditions in the dry season. Therefore, the non-carcinogenic risk in the dry season is higher than in the rainy season [1,45–48]. Kaur et al. [12] suggested that the hazard quotient values determined by deterministic and probabilistic approaches were nearly identical, and groundwater in most of the Panipat district in India is not suitable for direct drinking purposes.

The Chinese Loess Plateau (CLP) is a cradle of human civilization, where the groundwater plays an important role in the residents' lives and industrial and agricultural production. Due to the arid climate and increasing human activities, there is a serious shortage of water resources and a significant decline in water quality in the CLP [40]. Recently, health risks due to different water pollutants have been assessed on the CLP, such as fluoride [16], nitrogen [49], and arsenic [50]. However, these studies were mainly concentrated in the middle of the CLP. As for the Eastern Chinese Loess Plateau (Shanxi Province), the status of the groundwater environment and the threat of pollutants to human health are still unclear.

Therefore, this study was carried out to evaluate the quality and human health risks concerning groundwater in the Linfen Basin, a typical basin on the Eastern Chinese Loess Plateau. The objects of this study are (1) to analyze the hydrochemical characteristics of groundwater, (2) to evaluate groundwater quality using WQI, and (3) to assess the health risks of F−, nitrogen, and PTEs (Fe, Mn, Hg, As, Cd, Cr6+ and Pb) to adults and children through drinking water intake and dermal contact. A spatial distribution map of groundwater quality and health risks in the study area was produced using Inverse distance weight (IDW) interpolation in GIS. This study can provide meaningful support for local governments in groundwater quality protection and groundwater resource management.
