Aqueous geochemistry of high-fluoride groundwater in Datong Basin, Northern China

► Geochemical mechanisms of high fluoride groundwater at Datong were investigated. ► High fluoride groundwater is of transitional hydrochemical types. ► pH alone seems not to be a dominant factor controlling F− enrichment. ► The hydrolysis of F-bearing minerals is the dominant process affecting F− levels. ► The evaporation to a moderate extent favors F− enrichment, but is limited.