Measurement of radon concentrations and their annual effective doses in soils and rocks of Jaintiapur and its adjacent areas, Sylhet, North-east Bangladesh

The study investigates the measurement of radon concentration in soils and rocks as a natural tracer for exploring uranium mineralization, first of its kind in Bangladesh. The range of radon concentration was measured as 8–4360 Bq/m 3 with an average of 851.41 Bq/m 3 . Among the measured values, 2120–4360 Bq/m 3 was observed in the Tertiary sediments whereas 8–584 Bq/m 3 was found in the Recent alluvial soil of different bils and haors. These high radon concentrations are explained by geogenic factors such as mineral content in rocks, alluvium cover, sufficient porosity, probable subsurface fault, and flooding by water streamed through adjacent uranium-rich areas in India. The radon values indicate that the rock formations are promising for uranium mineralization. The radon concentration in rocks and soils are well comparable to the similar studies of the other parts of the world. The results are in good agreement with the previous radiometric survey results, suggestive to extensive exploration activities to confirm uranium mineralization in the area. Moreover, the average annual effective dose of 0.008092 mSv/y in the region calculated from the radon values is within the WHO and ICRP safety limits.