Hydrogeochemistry and human health risks of groundwater fluoride in Jinhuiqu irrigation district of Wei river basin, China

This study was carried out to investigate the hydrogeochemistry and spatial distribution of groundwater fluoride in Jinghuiqu irrigation district of China and to identify the hydrogeochemical processes and factors that control fluoride concentration. Water quality was assessed by comparing with the Chinese national groundwater quality guidelines and World Health Organization (WHO) guidelines for drinking water quality. Human health risks of fluoride were also quantified based on the US Environmental Protection of Agency (USEPA) model. The results show that groundwater in the study area is hard and slightly alkaline. The groundwater quality is generally very poor with excessive TDS, TH, Na+, SO42- and F- at some locations. The fluoride concentration in the groundwater samples ranges from 0.34 to 2.55 mg/L with an average of 1.08 mg/L, and 15.2% of the samples containing fluoride exceed the WHO guidelines of 1.5 mg/L for drinking water. High-fluoride groundwater mainly distributes in the southeast of the study area. The trend of fluoride concentration is consistent with the flow direction of groundwater. Groundwater fluoride mainly originates from natural sources and is controlled by hydrogeochemical factors such as alkaline environment, ion exchange, dissolution and precipitation of minerals. Health risk assessment results show that the non-carcinogenic risk for children is higher than that for adults and the health impact on adults is ignorable. The results of this study may help to set up suitable management strategies to guarantee water supply and health safety for local residents.