Hydrochemical character, water quality, and health risk assessment of shallow groundwater in the southern area of Chengdu city

Identifying the hydrochemical components and quality characteristics is a crucial precondition for the scientific utilization of groundwater resources. This paper comprehensively utilized hydrohemical methods, entropy-weighted water quality index (EWQI) and human health risk assessment model to study the groundwater in southern Chengdu. aiming to provide scientific references for the prevention and control of groundwater pollution and the construction of ecological civilization in the Chengdu-Chongqing Economic Circle. The results showed that the average values of pH and TDS of the groundwater were 7.24 mg·L−1 and 680.20 mg·L−1, respectively. The hydrochemical type was dominant by the HCO3-Ca type. The hydrochemical processes were mainly controlled by the weathering and dissolution of silicate and carbonate minerals, as well as the influence of anthropogenic activities. The entropy weight water quality index (EWQI) of groundwater ranged from 7.11 to 181.94, with a mean value of 51.30. The best groundwater quality was observed in the southwestern part. The mean values of potential non-carcinogenic risk for children and adults were 0.72 and 0.57, respectively, with the exceedances of 30.56% and 13.89%. Children faced a higher health risk, and the health risk values in the eastern part exceeds the limit seriously.