Study on Groundwater Quality in Chungcheongnam-do

The purpose of this study was to document groundwater quality in Chungcheongnam-do. Samples were taken from Taean, Dangjin, Seocheon, Boryeong, Seosan, and Nonsan areas, and 48 water quality variables were analyzed in relation to applicable standards, including the amounts of naturally occurring radioactive materials(U and Rn). The results from testing 179 locations indicated that 128 were suitable and 51 were of unacceptable quality, in terms of drinking water quality standards. The nonconformity rate for nitrate nitrogen was 47.0%, while that for total coliforms was 24.2%. Heavy metals-such as Pb, Hg, Cd, and Cr-were detected in low concentrations at all points. Analysis of naturally occurring radioactive materials showed that U concentrations were within the water quality standard (0.03 mg/L) at all points. Rn concentrations were low in NW regions such as Taean, Dangjin, Seocheon, and Boryeong, where Proterozoic sedimentary rocks were distributed, but its concentrations in the Seosan and Nonsan areas, where granite rocks were widely distributed, required closer investigation, and it was found that the alternative maximum contaminant level (148 Bq/L) was exceeded in granite soils which originated from the Mesozoic Era.