Hydrochemical insights, water quality, and human health risk assessment of groundwater in a coastal area of southeastern China.

Groundwater is a vital water supply worldwide, but its quality has gradually deteriorated with the development of society. In this study, a total of 40 groundwater samples were collected during the pre- and post-monsoon to analyze the hydrochemical process and assess the groundwater quality and human health risks in a coastal area of southeastern China. The results showed that the concentrations of major ions were in the order of Ca > Mg > Na > K and HCO > SO > Cl > NO > F during the pre- and post-monsoon periods. A slight increase was observed during the post-monsoon period. The Piper diagram suggested that the hydrochemical type of groundwater was predominantly HCO-Ca. Principal component analysis (PCA), ionic ratios, and saturation index (SI) determined that the water-rock interactions involving silicate and carbonate minerals played a significant role in the hydrochemical process. The results of the entropy-weighted water quality index (EWQI) and irrigation water quality index (IWQI) evaluations revealed that the general qualities of groundwater were suitable for both drinking and irrigation purposes. However, the excesses of NO and SO were observed locally. Human health risk assessment concluded that groundwater posed a low risk to human health, and infants faced higher risk compared with adults. The study would provide valuable information for groundwater environmental protection.