Radon exhalation rate from soil and rock samples of Chamaraja Nagara district, India

Radioactivity is a natural and manmade phenomenon and is omnipresent in the earth's crust in different amounts. The soil and rock on the earth's crust is a source of continuous exposure to human beings. Radon gas is a natural element of the environment and a risk factor for lung cancer. The majority of radiation exposure of the population comes from radon and indoor radon has been recognized as one of the health hazards for people. Materials of high radium content have been used at construction works in several countries and these may also act as considerable radon sources. To measure the radon exhalation rate and radium concentration from the soil and rock samples collected from different villages of Chamaraja Nagara district, Karnataka, by employing 'Can Technique' using solid state nuclear track detectors (LR-115 type II). The mass exhalation rate of radon in soil samples has been found to vary from 0.002 to 3.28 mBqkg-1h-1 with an average value of 0.38 mBqkg-1h-1 and standard deviation of 0.19. The surface exhalation rate of radon 0.003 to 1.65 mBqm-2h-1 with an average value of 0.26 mBqm-2h-1 and standard deviation of 0.162. Radium concentration in soil and rock samples has been found to vary from 0.15 to 28.13 mBqkg-1h-1 with an average value of 8.097 mBqkg-1h-1. (author)