Measurements of radon exhalations and radiological doses using LR-115 (II) nuclear track detectors in Tiru region of the Naga Schuppen Belt, India

In this present study, the nuclear track detector LR-115 (II) was employed to assess radon (222Rn) exhalation rate, effective radium (226Ra) content, and the annual effective dose from coal and soil samples collected in and around the coal mining area of Tiru region of Nagaland, India. The 222Rn mass and surface exhalation rates and 226Ra contents were found to be in the ranges of 7.3-17.3 mBq kg-1 h-1, 242.9-573.6 mBq m-2 h-1 and 1.0-2.3 Bq kg-1, respectively, for coal and 15.8-22.0 mBq kg-1 h-1, 523.8-730.4 mBq m-2 h-1 and 2.1-2.9 Bq kg-1, respectively, for soil. The 222Rn exhalation rates and 226Ra contents in soils were found to be higher than in coal. The estimated annual effective doses for coal and soils were found to be in the ranges of 17.6-41.6 and 38.0-53.0 μSv y-1, respectively. This study is an important contribution to the understanding of radiation exposure in the coal mining area of the thrust-bound sedimentary sequence of the Naga Schuppen Belt, and it would have potential impact on further human health studies. However, the measured values for all the samples were found to be within the globally recognised permissible range.