He Zhang, Jiangyulong Wang, Tao Cui
The assessment of nitrate pollution in groundwater is crucial for ensuring the safety of groundwater quality and related human health risks. This study conducted a comprehensive hydrogeochemical survey in an area strongly influenced by mining areas and human activities. A total of 236 groundwater samples were collected. The range of nitrate concentration was 0.020 mg/L to 658.0 mg/L, with 78.4% of the samples exceeding the recommended limit of 10 mg/L by the Chinese Guidelines. As the nitrate content increases, the chemical type of groundwater shifted from HCO₃-Ca type to ClCa type. The human input generated by residential land was the driving factor for nitrate enrichment and salinity increase. The calculation results of Entropy Weighted Water Quality Index (EWQI) showed a range of 4.9 to 650.8, with a mean of 41.6. Based on the current situation of land use, the causes of various excessive hydrochemical parameters were analyzed, and corresponding improvement suggestions were proposed for the local situation. The non-carcinogenic risk assessment indicated that the total risk range for infants was 0.0034 to 8.7 (mean 0.78), children ranged from 0.0021 to 5.4 (mean 0.48), adult females ranged from 0.0015 to 3.9 (mean 0.34), adult males ranged from 0.0018 to 4.6 (mean 0.41). The groundwater health risk of nitrate ranged from 0.0012 to 8.7, and the threat mainly came from oral ingestion of nitrates, with minors (infants, children) being more susceptible. The results can provide a scientific perspective for the sustainable development and utilization of groundwater resources and public health protection in adjacent mining areas.