Study of radon exhalation rates from coal using solid state nuclear track detectors

Abstract

In this paper, we present the results of radon (²²²Rn) exhalations rates along with radium contents and annual effective dose in the coal-mining areas of Assam, India using LR-115 (II) nuclear track detectors. The mass exhalation rates for coal in Makum coalfield and Dilli-Jeypore coalfield have ranged 5.8 ± 1.15–19.7 ± 2.98 mBq kg⁻¹ h⁻¹ and 17.1 ± 2.60–28.7 ± 3.65 mBq kg⁻¹ h⁻¹ respectively. The surface exhalation rates for coal ranged 2.15 ± 0.42–7.27 ± 1.10 mBq m⁻² h⁻¹ and 6.32 ± 0.96–10.57 ± 1.34 mBq m⁻² h⁻¹ in Makum coalfield and Dilli-Jeypore coalfield respectively. The radium contents in the coal have been found to be in the range 0.8 ± 0.15–2.6 ± 0.40 Bq kg⁻¹ and 2.3 ± 0.35–3.8 ± 0.49 Bq kg⁻¹ in Makum coalfield and Dilli-Jeypore coalfield respectively. The annual effective doses due to radon have been estimated to be in the range 0.16 ± 0.03–0.53 ± 0.08 $\upmu {\text{Sv y}}^{ - 1}$ and 0.46 ± 0.07–0.77 ± 0.10 $\upmu {\text{Sv y}}^{ - 1}$ respectively.