Groundwater hydrochemical characteristics and health risk assessment in the plain area of Yuncheng Basin

To elucidate the hydrochemical characteristics and associated health risks of groundwater in the Yuncheng Basin, this study employed a range of methodologies, including statistical analysis, Piper diagrams, Gibbs diagrams, ion ratios, and factor analysis. Additionally, the Monte Carlo method was utilized to assess potential risks related to nitrate (NO3−) contamination of the groundwater. The findings revealed that the groundwater in the study area is generally weakly alkaline, with sodium ions (Na+) and bicarbonate ions (HCO3−) as the predominant cation and anion, respectively, and that the primary water chemistry type is HCO3–Na. The groundwater chemistry is primarily influenced by rock weathering and cation exchange processes, with 16% of sampling points exhibiting significant anthropogenic impacts. The health risk assessment indicated that 12% of the groundwater samples were unsuitable for drinking during the sampling period. Moreover, the Monte Carlo simulation results suggested that non-carcinogenic health risks are 1.12 times higher for children than for adults, with nitrate concentration being the principal factor influencing health risks, followed by exposure frequency. Monitoring fertilization and pesticide application in agricultural practices to mitigate non-point source pollution is critical.