Studies on Indoor and Outdoor Radon/Thoron Concentration and Estimation of Radiological Parameters from Gamma Dose Rates along the Coastal Regions of Trivandrum and Kollam Districts, Kerala, India

Abstract

The indoor and outdoor radon and thoron and γ-exposure rates were measured in different types of houses in selected locations along coastal regions of Trivandrum and Kollam districts, Kerala, which are reported as high-background-radiation areas (HBRAs). The dose to lungs due to indoor radon, the annual effective dose due to radon and thoron, and the γ-dose rates were estimated. The average concentrations of radon and thoron are well within the action level recommended by ICRP. The average effective doses are also within the safe limit (3-10 mSv year⁻¹). The average value of excess lifetime cancer risk (ELCR) is 6.8 × 10⁻³, being higher than the world-average value of 0.29 × 10⁻³.