Hydrochemical characteristics and fluoride enrichment mechanisms of high-fluoride groundwater in a typical piedmont proluvial fan in Aksu area, Xinjiang, China

In inland arid regions, high fluoride concentrations are frequently reported in groundwater which is an important source of drinking water. Investigating its distribution, enrichment and controlling factors could provide insights for better understanding the geochemistry of high-fluoride groundwater, and are critical foundation to ensure the safety of water supply in inland arid regions. To delineate the distribution of high-fluoride groundwater, a comprehensive hydrogeochemical investigation has been conducted in a typical piedmont proluvial fan in Aksu area, Xinjiang, China. The relationship between fluoride concentration and various geochemical parameters has been analyzed for identifying the controlling processes of groundwater fluoride enrichment in this region. The results are: ①Fluoride concentrations in groundwater range from 0.8 to 6.1 mg/L, and 83% of the samples exceed the maximum limit of 1.0 mg/L set by the sanitary standards for drinking water (GB 5749-2006). ②The fluoride concentration was foun