| Summary: | Groundwater is an important source of drinking water, particularly in arid regions. In this study, a total of 66 groundwater samples were collected from the phreatic aquifer in the Shizuishan area, a traditional irrigation region of Ningxia. The results showed that the TDS values were above the drinking water standards for nearly 50% of the groundwater samples. The ions followed the order of Na<sup>+</sup> > Ca<sup>2+</sup> > Mg<sup>2+</sup> > K<sup>+</sup> and SO<sub>4</sub><sup>2−</sup> > Cl<sup>−</sup> > HCO<sub>3</sub><sup>−</sup> in the groundwater. There were four dominant factors in controlling groundwater chemistry based on principal component analysis: the salinity factor, alkalinity factor, carbonate factor, and pollution factor. The high concentration of NH<sub>4</sub>-N in groundwater was attributed to agricultural activities, but the high NO<sub>3</sub>-N levels were mainly due to sewage or wastewater. F and As were derived from geogenic sources. Based on the result of the WQI assessment, about 40% of the samples in the central part of the study region showed unacceptable water quality for drinking, which was mainly associated with high NH<sub>4</sub>-N, TDS, and As concentrations. The total non-carcinogenic risks of drinking the groundwater were 0.05–10.62 for adults and 0.09–20.65 for children, respectively. The order of pollutants in the groundwater in terms of their hazard to residents was: As > F<sup>−</sup> > NO<sub>3</sub>-N > NH<sub>4</sub>-N. The carcinogenic risk values of As through oral ingestion for children and adults were 0–7.37 × 10<sup>−4</sup> and 0–1.89 × 10<sup>−4</sup>, respectively. Chronic exposure by oral ingestion presented as the main source of susceptibility to exposure to groundwater contaminants for children.
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