Occurrence and Health Implication of Fluoride in Groundwater of Loess Aquifer in the Chinese Loess Plateau: A Case Study of Tongchuan, Northwest China

This study was carried out to delineate the occurrence and spatial distribution of groundwater fluoride in a loess area of China and to determine the geochemical and anthropogenic factors that influence its concentration. Water quality was assessed for drinking purpose by comparing with the national and WHO drinking water guidelines, and the impacts of fluoride on human health were also quantified using the health risk assessment model recommended by the USEPA. The results demonstrate that groundwater in the study area is slightly alkaline in nature, and its quality is generally good except slightly excessive TDS, TH, Na+, F-, and nitrate at some local locations. High-fluoride groundwater is mainly distributed in the southeast part of the study area, which is in accordance with the groundwater flow direction in this area. Groundwater fluoride is mainly of natural origin and is dominantly controlled by natural factors such as pH, specific hydrochemical environment, ion exchange, and saturation state of minerals. Fluoride contributes the most to the total health risk in the present study. Children are at higher health risk than adults in this area. Establishing central water supply system and rainwater harvesting system are suggested to guarantee safe drinking water supply in this area.