Studies on radon exhalation rate and activity of radioactive elements in soil samples and their radiological hazards to the population of Davanagere District, Karnataka, India

Exhalation rate of (super 222) Rn from soil samples and the activity concentrations of (super 226) Ra, (super 232) Th and (super 40) K were studied in soil samples of Davanagere district, Karnataka state, India. (super 222) Rn exhalation rate was measured using smart radon monitor (SRM). The mass exhalation rate of (super 222) Rn varies from 6.9 + or - 1.7 to 38.5 + or - 3.3 mBqkg (super -1) h (super -1) with a geometric mean of 20.1 + or - 2.5 mBqkg (super -1) h (super -1) . The surface exhalation rate of (super 222) Rn varies from 0.39 + or - 0.1 to 2.15 + or - 0.18 Bqm (super -2) h (super -1) with a geometric mean of 1.12 + or - 0.14 Bqm (super -2) h (super -1) . Activity concentrations of the radionuclide in soil samples were measured using HPGe detector. (super 226) Ra, (super 232) Th and (super 40) K concentration varied from 32.0 to 106.1 Bqkg (super -1) , from 19.6 to 78.8 Bqkg (super -1) and from 20.1 to 968.0 Bqkg (super -1) respectively. The average activity of (super 226) Ra in the soil samples was 63.2 Bqkg (super -1) which is higher than the global average and the Indian average value, whereas the activities of (super 232) Th and (super 40) K were found to be 34.9 Bqkg (super -1) and 458.8 Bqkg (super -1) respectively and are comparable to global average values. When the structural and physical properties of the soil samples were similar, radon exhalation rate from soil samples shows good correlation with its (super 226) Ra activity.