Evaluation of Groundwater Quality in Crystalline Bedrock Site for Disposal of Radioactive Waste

This study evaluated the evolution stage and origin of chemical components of 12 boreholes at crystalline bedrock using multivariate statistical and groundwater quality analyses. Groundwater types are mostly belonged to Na(Ca)-HCO3 and Ca-HCO3 types, indicating that directly reaction of cation exchange (Ca 2+ → Na+) prevailed. The degree of groundwater evolution is included the range from low to intermediate stage based on field and laboratory analytical conditions. As a result of multivariate statistical analysis, a typical indicator of groundwater contamination, NO3-, has the positive correlation with Na+ and Cl-. The origin of sea spary (Cl-) has the positive correlation with Na+, SO4 2-, Mg2+, and K+, while not correlation with Ca2+, Fe2+, HCO3 -, F-, and SiO2. The concentration of Cl and NO3 belongs to general quality of groundwater and not exceeds over the Korean standard for drinking water. And the negative values of saturation index of minerals are calculated with chemical components in groundwater. Therefore, most of chemical components of groundwater in the study area are originated from natural process between rock and groundwater, whereas some of components are derived from sea spary and anthropogenic sources related to agricultural activities.