Comparative study of radon sources and associated health risk in four underground uranium mines

This paper presents a comparative study of the quantitative estimation of 222Rn and its health risk from various sources in four underground uranium mines. 222Rn exhalation rates from uranium-bearing rocks and backfill materials were estimated by calculating the 222Rn concentration accumulated in an enclosed chamber into which radon was exhaled. This comparative study indicates a more significant effect of porosity on the exhalation rates. Dissolved 222Rn in mine water was estimated using scintillation cell and bubbler kit. The discrepancy in 222Rn concentration in the mines might be attributed to the variation in geological features, ore grade, and porosity. This study revealed that the maximum radon exposure was produced from the backfill mill tailings, followed by uranium ore and mine water in the mines. The radon dose values in the individual mines remained under the safe dose limit of 20 mSv year−1. The excess lifetime cancer risk (ELCR) and 222Rn-induced lung cancer cases (RnLCC) per million persons per year were also estimated.