Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8081684 | Journal of Environmental Radioactivity | 2016 | 8 Pages |
Abstract
The Chhatrapur placer deposit is found in a high background radiation area which has been recently identified on the southeastern coast of India. Previously, some geochemical studies of this area were carried out to assess external dose from radionuclides-bearing heavy mineral sands. In this study, radon, thoron and thoron progeny concentrations were measured in about 100 dwellings during three seasons (autumn-winter, summer, and rainy) in a 10- to 12-month period and annual doses due to inhalation of them were evaluated. The measurements were made by passive-type radon-thoron discriminative detectors and thoron progeny detectors in which solid state nuclear track detectors were deployed. The results show that radon and thoron concentrations differ by one order of magnitude depending on exposure periods, while thoron progeny concentration is nearly constant throughout the year. Since thorium-rich sand is distributed in the studied area, exposure to thoron is equal to, or exceeds, exposure to radon and is not negligible for dose evaluation. Based on the measurements, doses due to inhalation of radon and thoron are evaluated as 0.1-1.6 mSv yâ1 and 0.2-3.8 mSv yâ1, respectively. The total dose is 0.8-4.6 mSv yâ1, which is the same order of magnitude as the worldwide value.
Related Topics
Physical Sciences and Engineering
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Nuclear Energy and Engineering
Authors
Yasutaka Omori, Ganesh Prasad, Atsuyuki Sorimachi, Sarata Kumar Sahoo, Tetsuo Ishikawa, Devulapalli Vidya Sagar, Rakesh Chand Ramola, Shinji Tokonami,