Water quality and health risk assessment of shallow groundwater in the southern margin of the Tarim Basin in Xinjiang, P. R. China

In this study, 266 shallow groundwater samples were collected, and pH, TH, TDS, concentrations of main cations (K+, Na+, Ca2+ and Mg2+), main anions (Cl−, SO42− and HCO3−), NO2-N, NO3-N, NH4-N, F−, As, Fe, Cu, Mn, Zn, Hg, Cr6+, Pb and Cd were analyzed to assess the quality and health risk of shallow groundwater in the southern margin of the Tarim Basin. Results showed that groundwater in the study area was weak alkaline with hydrochemistry type by SO4•Cl-Ca•Mg and SO4•Cl-Na primarily. Groundwater chemical characteristics were mainly affected by rock weathering and evaporation concentration. Groundwater in this area is unsafe for drinking due to poor water quality, which mainly affected by natural environment as well as industrial and agricultural activities. Total carcinogenic risk and total non-carcinogenic risk of shallow groundwater in the study area were high, which exceed acceptable health risk level. The order of non-carcinogenic health risks from high to low were Cr6+, Cd, F−, As, Cu, Fe, Pb, Hg, NO3-N, Mn, NO2-N, NH4-N, and Zn, and the order of carcinogenic health risks were Cr6+, Cd and As, among which Cr6+, Cd, F− and As were the main indicators of healthy risk management controls.