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Study of correlation between indoor radon, thoron and their progeny levels in Srinivasanagar, Bangalore city, India

K.G.Shivaram, S.Sundareshan, L.A.Sathish, T.V.Ramachandran

Exposure of persons to high concentrations of radon and its progeny levels for a long period leads to pathological effects like the respiratory functional changes and the occurrence of lung cancer. It is indicated that the inhalation of short-lived 222Rn daughters seems to be the most important component of the radiation exposure of the population from natural sources. According to an estimate, 222Rn gas may be the major source of public radiation exposure, perhaps accounting for between 5 and 20%of all lung cancer deaths. In view of this an attempt has been made for the measurements of radon and thoron by using solid state nuclear track detector based dosimeters. The average annual dose to the population of Bangalore city due to radon and thoron daughter activity works out to be 1.98m Sv y-1. All India mean effective dose equivalent is 2.49mSv y-1and the global effective dose equivalent is 2.4mSv y-1.Seasonal variations in the concentration of indoor radon/thoron and their progeny concentrations are observed with higher values in winter and lower in summer. Astrong correlation coefficient was observed between 222Rn, 220Rn and their progenies.