Natural radioactivity of geothermal water in Beijing, China

In this work, we collected 101 geothermal water samples to investigate comprehensively the radioactivity of geothermal water in Beijing. The concentrations of gross beta, 226 Ra and 222 Rn were measured and the obtained values were in the range of 0.032–7.060, 0.023–0.363 and 0.470–29.700 Bq/L, respectively. The samples with higher concentration of 222 Rn were found to be located near large faults. The effective dose of 222 Rn in the air for three cases were calculated to be greater than radiation dose limit of 1 mSv/a.