Measurement of radon and thoron concentrations in the indoor atmosphere and drinking water of eastern Doon valley, India

Radon and radium content were measured in water samples from tubewells and handpumps in the eastern Doon valley, India. Activity due to the radon concentration was found to vary from 25.4 to 72.3 Bq L-1, whereas activity due to radium in selected water samples varied from 0.10 to 0.84 Bq L-1. The values recorded for radon were generally higher than those reported by various other workers for drinking water but well below the maximum levels that have been recorded. Measurements of indoor radon, thoron and their daughter products were also made in the houses in the same area for all the four seasons of a year on a time integrated cycle using twin chamber dosimeters. Concentrations of indoor radon and thoron varied from 28.4 to 63.7 Bq m(-3) and 0.01 to 15.9 Bqm(-3), respectively. The total resultant radiation dose to occupants in the houses surveyed in the eastern Doon valley varied from 0.03 to 0.11 muSv h(-1). A detailed analysis of the radon and thoron distribution in different houses with seasonal variation and ventilation conditions and a description of the geology of the area is presented in this paper.