Hydrochemical characteristics of groundwater and stream water in a karst area of Samcheok, Korea

This study examines the chemical evolution of stream water and groundwater in the karst area of Samcheok city. The stream water and groundwater in this area are characterized by high levels of Ca2+ and HCO3-, which is a result of water-carbonate rock interaction, especially calcite dissolution. The delta C-18 and ionic ratios also indicates carbonate rock dissolution is a dominant factor controlling the water chemistry in this area with a small contribution of atmospheric CO2 dissolution. The coastal stream water was highly affected by seawater, showing high concentrations of Na+ and Cl-. The stable isotopic compositions (delta D and delta O-18) and ionic ratios of Na+ and Cl- indicate that the stream water is originated from a single source, nearby seawater evaporation from East Sea rather than typical evaporation of Yellow Sea, transported by the prevailing westerlies.