Comparison of groundwater levels and groundwater qualities in six megacities of Korea

This study was conducted to compare groundwater levels and groundwater qualities among six megacities such as Seoul, Busan, Daegu, Incheon, Daejeon, Ulsan in Korea. To this end, groundwater levels (2001-2011) and groundwater qualities monitoring data (2001-2010) were obtained from the Korea National Groundwater Monitoring Stations. Groundwater levels in the six megacities were affected by impermeable pavement, subway and well pumping. Due to the urbanization effects, groundwater levels in the megacities were lower than those found in the outskirts. Coliform and NO3-N were the major groundwater contaminants in the megacities. In particular, groundwater in Incheon showed elevated Cl concentrations (21,120 mg/L) and electrical conductivities (49,400 mu S/cm), indicating the infiltration of seawater and salinized river water. Detection frequency of TCE, PCE, heavy metal (Hg, Cr6+, As, Cd) and CN contamination were low in the six megacities.