Abstract

The characteristics of hydrogeochemistryand fluorine distribution in drinking groundwater from limestone and granite were studied in the Keumsan-Wanju area, where major important fluorite-deposits are distributed. The hydrochemical properties of groundwater from studied area are commonly characterized as Ca-HCO₃ water type. However, some of the groundwater samples collected from Jurassic and Cretaceous granites belong to Ca-Na-HCO₃and Na-HCO3 type, respectively. The contamination of drinking groundwater by minewater from the nearby fluorite deposits is not foundyet. However, groundwater having high Econtents up to 11.4 mg/?, which is higher than the drinking water limit, is found from the wells located in Cretaceous granite. The fluorite contents in groundwater generally increase with increasing well depth. The concentrations of F in the groundwater show a positive relationship with the values of Na, HCO3, C1, SiO₂, pH, whereas a negative relationship with Ca. The positive correlation of concentrations to major elements (SiO₂, Na, C1) and trace elements (Li, B, Rb) may suggest that the groundwater come from the decomposition of fluoride-bearing silicate minerals within highly differentiated granitic rocks. Therefore, wells for drinking water should not be developed or should be drilled within shallow level in the Cretaceous granite region to reduce the F contents in the groundwater.

Keywords

fluorite deposits, groundwater, fluorine, Cretaceous granite