Fluorine sorption by soils developed from various parent materials in Galicia (NW Spain)

► Most Galician natural soils are acid and show a high F sorption. ► F sorption by natural Galician soils fitted both Langmuir and Freundlich isotherms. ► A horizons sorbed generally more fluoride than B horizons. ► Non-crystalline materials were the main responsible for F sorption in Galician soils. ► The risk of fluoride phytotoxicity increased above pH 6.