Measurement of Indoor Radon, Thoron and Dose Rates in Some Dwellings of Punjab

Radon (Rn-222) and its decay products are the major source of the inhalation dose received by humans due to natural radioactivity. This environmental radioactivity could lead to significant potential risk for living beings as it includes harmful radionuclides. The present work deals with assessment of annual effective dose rates due to indoor radon and thoron in some of the dwellings of Punjab. The equivalent dose rate to lungs (H) due to indoor radon has also been estimated. The indoor radon concentration varies from 18.3Bq m(-3) to 122.2Bq m(-3) with average value of 63.86Bq m(-3). The thoron concentration varies from 23.3 to 172.2Bq m(-3) with average value of 89.45Bq m(-3). The average values of annual effective dose due to radon and thoron are 1.847 mSv and 2.25 mSv respectively. The higher values of thoron may be due to the higher amount of Thorium (Th-232) present as compared to the Radium (Ra-226). Equivalent dose rate to lungs varies from 14.64 to 97.8 nSv with average value of 51.15 nSv. The mean value of the inhalation dose from Rn-222 and Rn-220 in the study area is less than the world's average mean inhalation dose for Rn-222 and Rn-220. Therefore, the health hazards related to radiation are expected to be negligible in the studied area.