Radon concentrations in the community groundwater system of South Korea.

Groundwater samples were collected from 3818 wells used for the community groundwater system (CGS) in the remote rural areas of South Korea and analyzed to determine radon concentrations. Radon concentrations varied with rock type, ranging from 0.1 to 2393.5 Bq/L with an average of 86.6 Bq/L and a median of 46.4 Bq/L. Among 10 geological units, the median CGS radon concentration was highest (59.6-103.0 Bq/L) in granite, and lower in sedimentary rocks (16.9-21.1 Bq/L) and porous volcanic rocks (17.6 Bq/L), respectively. Of the 3818 samples, 26.1% exceeded the World Health Organization (WHO) radon level limit of 100 Bq/L. The application of the natural radon reduction rate (26.5%) recently suggested by Yun et al. Applied Radiation and Isotopes, 126(1), 23-25 (2017) to the CGS water tank appeared to decrease exceedance of the WHO radon level limit to 20.2%. Because of the high radon concentrations in CGS groundwater in South Korea, the establishment of a radon level limit for drinking water is strongly recommended to ensure the health and safety of the people using CGS water.

Natural radon reduction rate of the community groundwater system in South Korea.

Tank waters from 13 Community Groundwater Systems (CGS) showed average radon reduction rate of 26.5% (varying from -17.9% to 63.3%). When applying the reduction rate of 26.5% to the nationwide CGS, the percentage of CGS having radon level above 100Bq/L decreases from 28.8% to 22.0%. The natural radon reduction method would be applied to the CGS having radon level slightly exceeding guideline of WHO, as an alternative for aeration or GAC.