RADON-THORON MEASUREMENTS IN AIR AND SOIL FROM SOME DISTRICTS OF NORTHERN PART OF INDIA

Radon, thoron and their progenies in the indoor environment are considered as one of the health hazards. The alpha emitting nature of these gases made it possible to detect in indoor environment with the help of nuclear track detector techniques. The soil is the main source of indoor radon as it contains varying amounts of uranium and thorium. Thus the exhalation of radon from soil and its environmental activity needs to be studied. In the present study, the measurement of the indoor radon-thoron from the indoor environment and exhalation from soil are carried out using solid state nuclear track detector technique from Sirsa and Bhiwani districts of northern part of India. The canister technique was used to measure the radon exhalation rate from the soil samples collected from the study area and pinhole based radon-thoron dosimeters were used to measure indoor radon and thoron concentration. The results show that indoor radon concentration varied from 9 to 28 Bq/m(3), with an average of 18.9 Bq/m(3) and from 5 to 21 Bq/m(3), with an average of 13.8 Bq/m(3), for Bhiwani and Sirsa, respectively. Similarly, thoron concentration varied from 14 to 48 Bq/m(3), with average of 28.9 Bq/m(3) and 27 to 54 Bq/m(3), with the average of 39.0 Bq/m(3), for Bhiwani and Sirsa, respectively. The mass exhalation rates from soil samples were also measured, to estimate their contribution to indoor radon. A correlation study was carried out between soil exhalation rates and indoor radon concentration.