Radiation hazards associated with radionuclides and theoretical evaluation of indoor radon concentration from soil exhalation of Udhampur District, Jammu and Kashmir State, India

Abstract

Soil is the prime source of radon and thoron concentrations in the household dwellings. The presence of radioactive gases in the environment is mainly due to the presence of radionuclide content in soil, rocks, and building materials. So, it is necessary to estimate the radionuclide content in the living environment. The annual effective dose has been assessed from the radionuclide content, and an effort has been made to correlate the concentration of these radionuclides with exhalation rates of their daughter products, i.e., radon and thoron. Theoretically determined indoor radon concentration has also been compared with experimentally observed results. Scintillation-based Smart RnDuo monitor (SRM) and gamma spectrometry (NaI(Tl)) have been utilized for the estimation of exhalation rates and radionuclide (226Ra, 232Th, and 40K) contents in soil samples. The range of radon mass and thoron surface exhalation rate in soil samples are found to vary from 11.57 to 65.62 mBq kg−1 h−1 with an average of 28.20 mBq kg−1 h−1 and from 52 to 930 mBq m−2 s−1 with an average of 312 mBq m−2 s−1, respectively. The average activity concentrations of 226Ra, 232Th, and 40K are 24.52 Bq kg−1, 41.15 Bq kg−1, and 343 Bq kg−1, respectively. The average values of 226Ra, 232Th, and 40K are well within the safe range recommended by the United Nations Scientific Committee on the Effects of Atomic Radiations. The calculated annual effective dose and radiation hazard risks have been found to be well below the recommended levels. Results obtained from theoretical evaluation are compared with experimentally obtained results and are in good agreement with each other. Different occupancy factors have also been analyzed according to the populace indoor occupancy.