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

A study on measuring the 222Rn in the Buriganga River and tap water of the megacity Dhaka

“…Certain rock types such as granites, metamorphosed granitic rocks, phosphate rocks with enriched uranium, coal deposits, black shale fractured/faulted rocks, and the subsequent soils resulting from these rocks are the most common sources of radon gas [ 56 , 59 , 60 ]. On the other hand, quartzose sandstone, non-organic shales, and siltstones are the least likely sources of radon [ 61 ], but under a favorable reducing environment, uranium mineralization may occur in alluvial-type sedimentary deposits which can then contain and emanate radon [ 59 ]. Based on the above facts and the geology of the study area, the radon potential and their associated health risks are evaluated in this study.…”

Natural radioactivity and its radiological implications from soils and rocks in Jaintiapur area, North-east Bangladesh

“…Heavy minerals might be present at sample locations with high 226 Ra and 232 Th concentrations, while light minerals might be present in sampling locations with high 40 K concentrations. The probable reasons for higher activity concentration in soil include presence of higher organic matter content, dominance of minerals (smectite, clays, and carbonates), the difference in the underlying bedrocks, and the inundation of these area during flooding through several streams and channels flown through the different formations exposed in nearby highly radioactive Khasi and Jaintia hills of Shillong Plateau, Meghalaya, India and Tertiary succession of Jaintiapur Area of Surma basin which carry various sediments from different formations having diverse age range [ 12 , 44 , 45 ]. The activities of radionuclides in the soil samples may vary locally even in shorter distance due to multi-channel sediments deposition which we have observed during in-situ field measurements.…”

“…Similar studies from Shillong Plateau, Meghalaya, India also showed that the variation of the radioactivity content from location to location is because of the variation of these elements in different geological formations of oldest Precambrian gneissic complex to Recent alluvium soil [ 46 , 47 ]. Therefore, the reasons for fluctuating activity concentrations in the studied area include the variation of mineralogical and chemical composition of rock formations exposed in the studied area which were deposited in varied depositional settings such as continental to marine in the geological past, the presence or absence of alluvium covering and compactness of sandstone [ 12 , 16 , 48 ]. A close observation during the field survey revealed that black patches on the soils indicating the presence of thorium in the studied samples and the variation arises due to varying grades of monazite deposition in the samples.…”

“…In Meghalaya, the uranium containing host rock is feldspar rich Arkosic sandstone and the thorium containing host rock contain monazite [ 46 ]. Besides, the anthropogenic activities such as use of fertilizer containing potassium in the haor and bills area during agricultural activities and presence of stone crushing site nearby the studied area might result in variation of activity concentrations [ 3 , 12 , 45 ]. Thus, there is no significant correlation exist between radionuclides in soil samples and activity of radionuclides in rock samples of the study area.…”

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Fig. 1 a The regional geo-tectonic frameworks of the Bengal Basin (modified after [ 16 , 22 – 24 ] ) b Geological map of Jaintiapur and its adjoining areas showing the exposed geologic units and sample locations (modified after [ 12 , 16 ])

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