Investigation and analysis of radon concentrations in two groundwater supplies in a city

Objective To explore the effect of radon released from water on the indoor radon activity concentration in groundwater supplies. Methods Two groundwater supplies in a city were chosen. Radon concentrations in three kinds of water samples were determined by using a continuous radon monitor with air-water exchanger, including source water, finished water and tap water. The solid track detector was used to analyze the indoor radon concentration in water supplies. Results The concentrations of radon in source water, finished water and tap water were (7.59±1.36), (3.56±0.86), (3.68±0.81)Bq/L and (12.19±0.57), (7.87±1.12), (9.50±1.12)Bq/L, respectively. The concentration of radon was the highest in source water and at less varying level in finished water and tap water. Aeration and filtration tank process significantly decreased radon activity in water. Radon concentrations in aeration and filtration rooms were 4 218 Bq/m3 and 1 937 Bq/m3, respectively, which exceeded the limit in work place (1 000 Bq/m3). Conclusions Aeration and filtration workplaces for groundwater supplies were found to contain elevated radon concentrations in air, which was released from groundwater. Radon issues in groundwater supplies in China should be paid more attention. Key words: Radon; Groundwater; Water supply; Indoor air