Mathematical Modelling to estimate Radon exhalation rates: A study on soil samples from Pangi valley of Chamba district, Himachal Pradesh, India

Abstract

Radon being radioactive gas is the main source of radiation exposure in the environment. When inhaled, it may cause carcinogenic diseases due to alpha emission during the radon decay, as alpha particles may damage respiratory and alveolar epithelial cells. Thus continuous investigation of the radon level in the environment is always required. In the same, correlation between concentration of radium with radon exhalation rates in the soil samples may be very helpful to know the variation of the radon level. In present study soil samples have been collected randomly from various locations of Pangi Valley of Chamba district, Himachal Pradesh, a northern hill state of India. Radon exhalation rates in collected samples have been measured using the closed can technique in correlation to different soil parameters. Radon mass exhalation rate in soil samples have found to vary from 0.018 to 0.179 Bq kg-1 h-1 with an average value of 0.082 Bq kg-1 h-1 and area exhalation rate from 0.56 to 5.42 Bq m-2 h-1 with an average of 2.47 Bq m-2 h-1. A Mathematical model has been developed using soil parameters viz. bulk density, porosity, emanation rates, diffusion coefficients etc. and use to estimate the radon exhalation rates in soil samples. A strong positive correlation has been obtained between the theoretically estimated and experimentally measured obtained values.