Study on groundwater radon concentrations and its dose contribution in some cities in China

Objective To investigate the levels and distribution of radon concentrations in groundwater in some representative cities in China, and estimate the effective dose from inhaled radon released from domestic groundwater. Methods A total of 12 cities in 7 provinces (municipalities) were selected, including Beijing, Inner Mongolia, Ningxia, Shaanxi, Henan, Liaoning and Heilongjiang. In total, 73 water samples from groundwater supply were taken. Radon concentrations in water samples were determined by using a continuous radon monitor with air-water exchanger. Results The average radon content in groundwater for drinking was 11.8 Bq/L in 12 cities in 7 provinces, ranging from 1.0 to 63.8 Bq/L. The radon concentrations in 37% water samples exceeded 11.1 Bq/L, the safe limit recommended for drinking water by the United States Environmental Protection Agency (EPA). The radon contents in all of the water samples was lower than the reference level 100 Bq/L recommended by World Health Organization (WHO). The average annual effective dose arising from inhaled radon released from groundwater was 29 μSv (2.4 to 160 μSv). Conclusions Generally, the effective dose from inhaled radon released from groundwater is negligibly low. However, in some areas dominated by granite bedrock, the dose contribution from radon released from groundwater to residents should be routinely monitored. Key words: Domestic water; Drinking water; Groundwater; Radon content; Dose