Groundwater Quality Evaluation and Health Risk Assessment in the Yinchuan Region, Northwest China

Groundwater is an important resource for domestic and irrigation purposes in the Yinchuan Region, northwest China. However, the groundwater quality in this area is degrading because of human activities, and this adversely affects human health. In an effort to quantitatively describe the pollution status of groundwater and its influence on human health, comprehensive water quality index was used for drinking water quality assessment, and salinity-alkalinity method was applied to evaluate the irrigation water quality. Furthermore, the human health risk of the drinking groundwater has been evaluated with the model recommended by the United States Environmental Protection Agency. The results reveal that most of groundwater samples are suitable for irrigation except a few with high salinity and alkalinity. However, over 70 % of the phreatic water samples and nearly half of the confined water samples do not conform to the drinking water quality standard, and many parameters such as total dissolved solids, total hardness, and Na+ and SO42- exceed their limits. Noncarcinogenic risks of all collected water samples are relatively negligible. While carcinogenic risks in nearly 30 % of phreatic water samples and over 20 % of confined water samples surpass the acceptable level recommended by ICRP (5 x 10(-5) per year), Cr6+ is the main influencing factor on the risk. In addition, the study shows that the severe groundwater pollution in the study area is conjunctively caused by industry and agricultural activities. Therefore, effective measures must be implemented to prevent further deterioration of water quality and reduce the health risks for local residents.