HR: 1330h
AN: H42F-1136    [PDF]
TI: Factors influencing the occurrence of fluoride-rich groundwaters in in a faulted area of Korea
AU: * Kim, K
EM: kangjoo@kunsan.ac.kr
AF: Dept. of Environmental Engineering, Kunsan National University, San 68, Miryong-Dong, Kunsan, Jeonbuk, 573-701 Korea, Republic of
AU: Jeong, G
EM: jearth@andong.ac.kr
AF: Dept. of Earth and Environmental Sciences, Andong National University, 388 Songcheon-Dong, Andong, Kyeongbuk, 760-749 Korea, Republic of
AB: Factors regulating the fluoride concentration in groundwaters were investigated using natural isotope tracers and geochemical data in the southeastern part of Korea where not a few public water-supply wells show fluoride levels exceeding the drinking water limit (1.5 mg/L). In the study area, the F-rich public wells are distributed along the major faults, especially in the terrain of the F-rich granitic rocks. Their isotopic and geochemical characteristics are consistent with those of the deep-circulating paleogroundwaters, of which F concentrations are enriched by prolonged water-rock reactions. This observation reflects that rock chemistry, groundwater age, well depths, and pathways for the F-enriched deep groundwaters are the important factors for the occurrence of high F groundwaters. However, high F groundwaters are rarely observed in the faults where the associated fractures are widely developed. Isotopic signature provides an evidence for deep penetration of recently recharged groundwater into the fault zone, indicating that the artesian pressure, which moves the F-rich groundwater in the deep aquifer upward along the fault plane, is easily dispersed when the fault zone is wide. This shows that the hydrogeologic condition of the fault is also an important factor for the occurrence of high F groundwaters.
DE: 1806 Chemistry of fresh water
DE: 1829 Groundwater hydrology
DE: 1884 Water supply
DE: 1886 Weathering (1625)
SC: Hydrology [H]
MN: 2003 Fall Meeting