Radon exhalation measurements in soil and rock samples of Chamaraja Nagar area, Karnataka State, India

Natural radioactivity is widespread and omnipresent in earth's environment. The knowledge of distribution of radionuclide and radiation levels in the environment is important for assessing the effects of radiation exposure to human beings. Terrestrial radiation is due to the radionuclides present in different amounts in rocks, soils, building materials, water and atmosphere. The majority of radiation exposure of the population comes from radon, an α-radioactive, inert gas. Radon produces the main natural radiation exposure for human beings and has been recognized as carcinogenic gas. Radium and its ultimate precursor uranium are the main sources of radon. In the present study, Radon exhalation rate and Radium concentration in soil and rock samples around Chamaraja Nagar area of Karnataka state, India, are measured by SSNTD method, using can technique and LR-115 type II detectors. The radium activity in rock sample varies from 2.9 to 39.5 Bq.kg-1. Mass and Surface exhalation rate of radon in rock samples varies from 8.1 to 119.7 mBq.kg-11h-1 and 454.7 to 1787.3 mBq.m-2h-1 respectively. Radium concentration in soil samples has been found to vary from 3.6 to 34.1 Bq.kg-1 with an average value of 16.5 Bq.kg-1. The surface exhalation rate of radon 142 to 1377.3 mBq.m-2h-1. The mass exhalation rate of radon in soil samples has been found to vary from 10 to 31.4 mBq.kg-1h-1, with an average value of 19.3 mBq.kg-1h-1 and standard deviation of 7.6. (author)