Distribution and Geochemical Evolution of Fluoride in Groundwater of Taiyuan Basin, China

Hydrogeochemistry data were utilized to understand origin, distribution, and geochemical evolution of the high-fluoride groundwater in Taiyuan basin, China. In the study area, the spatial distribution of the high fluoride groundwater are strictly controlled by the host rock and geomorphic conditions. Three kinds of groundwater with the F^- concentration of < 1.5 mg/1,1.5~2 mg/1 and >2 mg/1 are located in the north of the basin with underlying limestone, in the mountain front pluvial fan of the southeastern basin with underlying sandstone of Permian and Carboniferous, and in the depressions of the central parts of the basin, respectively. The high fluoride groundwater mostly have the high values of TDS, and its values of pH ranges from 7.2 ~ 8.4. The most common water types of the high fluoride groundwater are Na·Ca-HCO₃ and Na·Mg-HCO₃. The geochemical mode reveals that the high fluoride groundwater behaves two kinds of the mechanism of hydrogeochemical evolution, namely the dissolution of the fluorine minerals, and the evaporation effect of the shallow groundwater.