Study of background radiation dose in Mysore City, Karnataka State, India

Inhalation of radon/thoron and their decay products is the major contribution to the total dose to the population from the natural radiation. Long duration measurements of these gases and their progeny concentrations were made in about 200 dwellings of the Mysore city using the SSNTD techniques for I year. The detector used at each house was fixed 2 m above the ground-floor. After the exposure time of 3 months films were etched in 2.5 N, NaOH solution at 60degreesC for 60 min. From the track density determined using spark counter, concentrations of radon/thoron levels were evaluated. The working level concentrations of radon/thoron was calculated from the equilibrium factor, leading to the estimation of the inhalation dose. Radon in bore-well water at different locations of Mysore city was examined using the emanometry and exposure dose from ingestion of drinking water was estimated. The ambient gamma radiation of equivalent effective dose both in indoor and outdoor at different parts of Mysore city was determined using scintillometer. The activity of Ra-226, Th-212 and K-40 in soil were measured using spectrometer. The concentrations of radon/thoron and their progeny, ambient gamma, the activity of Ra-226, Th-232 and K-40 presented and analyzed. (C) 2002 Elsevier Science Ltd. All rights reserved.