Measurement of radon and thoron levels in soil, water and indoor atmosphere of Budhakedar in Garhwal Himalaya, India

Environmental radiation exists as a consequence of cosmic, terrestrial and man made sources. Terrestrial radiation are emitted from natural radionuclide present in varying amounts in all types of soils, rocks, air, water and other environmental materials; radon is emitted from the soil surface, although secondary contributors include the oceans, natural gas, geothermal fluids, volcanic gases, ventilation from caves and mines, and combustion of coal. Radon and thoron levels were measured in soil-gas, ground water and indoor air in Budhakedar area of Tehri Garhwal, India. Radon concentrations in soil and groundwater of the Budhakedar area were found to vary from 1.10 +/- 0.29 to 31.8 +/- 1.6 kBq/m(3) with an average value 7.46 +/- 0.69 kBq/m(3) and 8 +/- 1 Bq/l to 3.05 +/- 0.02 kBq/l with mean value 0.51 +/- 0.01 kBq/l, respectively. Measurement of indoor radon, thoron and their daughter products were also measured in the houses of the same area for four different seasons (autumn, winter, summer and rainy) using LR-115 plastic track detectors. The detector is fixed in a twin chamber radon dosimeter, which can record the values of radon, thoron and their decay products separately. The film fixed in bare mode holder gives the concentrations of radon, thoron and their progeny while the films fixed inside the cup with filter and membrane modes give the concentrations of radon/thoron gases and of pure radon gas, respectively. Detailed analysis of the effects of seasonal variation on radon, thoron and their decay products inside the houses are reported in this paper. (C) 2008 Elsevier Ltd. All rights reserved.