Hydrochemistry appraisal, quality assessment and health risk evaluation of shallow groundwater in the Mianyang area of Sichuan Basin, southwestern China

摘要

Sixty groundwater samples were collected from the Mianyang area in Sichuan Basin for hydrogeochemical analysis, quality assessment, and human health risk evaluation. Principal component analysis (PCA), ratios of major ions and geochemical modelling were used to investigate the factors regulating the hydrogeochemical compositions. Groundwater samples were of Ca-HCO3 type and the average cation and anion concentrations were in the order of Ca2+ Na+ Mg2+ K+ and HCO3- SO42- Cl- NO3- F-. The hydrogeochemical compositions were dominated by calcite dissolution, silicate dissolution, and ion exchange. NO3- contamination was identified and attributed to anthropogenic activities. 65% (39) of the water samples were suitable for human consumption based on the entropy-weighted water quality index (EWQI). The human health risk was evaluated by the US Environmental Protection Agency (USEPA) mathematical model. The hazard quotient of nitrate (HQ(Nitrate)) and total non-carcinogenic health risk (HITotal) values contended that non-carcinogenic health risk was greater in infants as compared to children and adults. Therefore, appropriate remediation for decreasing nitrate concentration in drinking water was recommended to prevent further health risk. This research can provide references to ensure groundwater security and realize effective management of groundwater in the Mianyang area and other similar regions worldwide.