The Narim gold mine is located approimately 200km southeast of Seoul within the Muju mineralized district of the Sobaegsan gneiss complex, Korea. Environmental geochemistry were undertaken for various kinds of water (surface, ground and mine water) collected of April, September and November in 1998 from the narim mine creek. Hydrogeochemical compositions of water samples are characterized by the relatively significant enrichment of Na+K, alkali ions, HCO3, NO3, Cl and F in groundwater, wheras the mine and surface waters are relatively enriched in Ca+Mg, hea표 metals and SO4. Therefore, the groundwaters belong to the (Na+Ca)-(HCO3+SO4) typem respectively. The pH and EC values of the non-mining creek surfers are relatively lower compared with those of the surface water of the mine and ore dump area. The d values (δD-8δ18O) of all kinds of water from the Narim mine creek are 5.8 to 13.1 The range of δD and δ18O values (relative to SMOW) are shown in distinct two groups as follows: for the April waters of -64.8 to -67.8‰ and -9.6 to -10.0‰(d value=10.1 to 13.1), and for the November waters of -65.9 to -70.2‰ and -9.3 to -9.6‰ (d value=5.8 to 7.9), respectively. This range variation indicates that two group water were composed of distinct waters with seasonal difference. Geochemical modeling showed that mostly toxic metals (As, Fe, Mn, Ni, Pb, Zn) may exist largery in the from of metal (M2+) and metal-sulfate (MSO42-), and SO42- concentration influenced the speciation of heavy metals in the meteoric water. These metals in the groundwater could be formed of CO3 and (OH)3 complex ions. Using computer program, saturation index of albite, calcite, dolomite in meteoric water show undersaturated and progreddively evolved toward the saturation state, however, ground and mine water are nearly saturated. The gibbsited water-mineral reaction and stabilities suggest that the weathering of silicate minerals may be stable kaolinite, illite and Nasmectite. The clay minerals will be transformed to more stable kaolinite owing to the contiunous reaction.
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