Spatial groundwater quality and potential health risks due to nitrate ingestion through drinking water: A case study in Yan'an City on the Loess Plateau of northwest China

摘要

This research was carried out to delineate the spatial distribution of shallow groundwater quality in Yan'an City, an important cultural city on the Chinese Loess Plateau, and to estimate the health risks induced by nitrate exposure in drinking water in this city. For this study, 36 shallow groundwater samples were collected from shallow pumping wells/dug wells. The entropy-weighted water quality index (EWQI) was used to evaluate the overall groundwater quality, and the spatial distribution of the groundwater quality was discussed. The potential health hazards due to nitrate intake through drinking water were also assessed. The results of the study demonstrate that the main hydrochemical facies are governed by natural processes and anthropogenic activities. Over half of the groundwater samples require treatment of different degrees before being consumed. TH, TDS, SO42-, and NO3- are the most prevalent contaminants affecting the groundwater quality in this area. Poor-quality water is prevalent in the region along the main river. Residents in almost half of the study area face noncarcinogenic health risks with children being the more susceptible group to groundwater nitrate contamination. Reducing the concentration of NO3- in drinking water by regulating excessive fertilizer application and issuing regulations supervising the domestic sewage are important to reduce the health risks. Integrated management of groundwater and surface water as well as rainwater is recommended for the groundwater quality management.