Health-risk assessment and distribution characteristics of fluoride in groundwater in six basins of Shanxi Province, Middle China

High-fluoride (F) pollution is an environmental problem that severely affects the growth of human beings, animals and plants. High-fluoride groundwater severely harms the health of Shanxi residents and leads to frequent endemic diseases. This study aims to analyze the differences and possible health risks of fluoride among six basins in Shanxi Province, North China, using 338 groundwater samples collected from wells, infer the main sources of fluoride in the groundwater, and provide valuable suggestions for fluoride contamination in regional groundwater. The results revealed that F in the Yuncheng basin had the highest health risk. In addition to the Changzhi basin, the groundwater at the sampling points in other basins had adverse effects on human health. The main source of fluoride in groundwater is the dissolution of fluoride-containing minerals, which has little to do with human activities. The groundwater in Shanxi Province tends to be alkaline, and the fluorite saturation index is less than 0 in most circumstances, indicating that fluorite is in an unsaturated state, and fluoride will continue to dissolve into groundwater under suitable conditions. Clustering analysis shows that the high-fluoride areas are mainly distributed in the Yuncheng basin and the southern part of the Xinzhou basin. Fluoride-rich groundwater in a basin often exists only in a certain area, and the distribution of confined water and unconfined water in high-fluoride areas is different. Fluoride contamination in the Changzhi basin is not severe. For the high-fluoride areas in the Datong basin, Xinzhou basin, Taiyuan basin and Linfen basin, utilizing water from other areas or exploiting groundwater from other aquifers to diminish the harm of high-fluoride groundwater intake for a long period is suggested. For the Yuncheng basin, adopting membrane-based processes or variable temperature drop fluoride technology to make groundwater contaminated by excessive fluoride potable is recommended.