No abstract

No abstract

Abstract:The total background radiation in the earth's environment is due to the contributions from natural (cosmic and terrestrial) as well as artificial (fall-out

Natural radioactivity concentrations in recent alluvial soils from swampy areas and Tertiary rocks from Jaintiapur were measured using gamma-ray spectrometer equipped with HPGe detector. The average radioactivity concentration of 226 Ra, 232 Th and 40 K were 47 ± 6, 64 ± 5 and 762 ± 40 Bqkg −1 in soils, whereas, 25 ± 2, 37 ± 4 and 884 ± 41 Bqkg −1 in rock samples, respectively. Average radioactivity concentrations of studied soil and rock samples exceeded the world average except 226 Ra for rocks. Radio-elemental ratios suggest that an oxic depositional environment with low uranium and high thorium content. Regarding radiological hazard indices, radium equivalent activities (Ra eq ), external hazard index ( H ex ) and internal hazard index ( H in ) was found to be below the world permissible limits. Whereas, absorbed dose rate (D), and annual effective dose equivalent (AEDE) averages exceeded the world admissible values. Statistical studies show that radioactivity for 226 Ra and 232 Th linked to a source enriched in radioactive minerals and 40 K related to a different sources high in K enriched minerals.

Sand is one of the main materials used in the construction industry. Elevated concentrations of terrestrial radionuclides in sand may cause great harm to dwellers. Present study determines concentrations of terrestrial radionuclides in sand that is widely used as a raw material in the construction industry in Bangladesh, via conventional HPGe γ-ray spectrometry. The average activity concentrations of 226Ra, 232Th and 40K in the analysed samples were found as 36.8 ± 3.9, 58.9 ± 6.0 and 755 ± 91 Bqkg−1 in Base sand, 68.1 ± 5.3, 185.7 ± 9.9 and 1032 ± 104 Bqkg−1 in Sylhet sand, and 38.1 ± 3.6, 74.7 ± 5.9 and 636 ± 77 Bqkg−1 in Aster sand. All data show relatively higher values than the world average of 35, 30, 400 Bqkg−1, respectively. Key hazard parameters were estimated to realize the radiation effects on human health due to the use of sand as construction and building materials. The estimated parameters for Sylhet sand show relatively higher values than the population-weighted world average values, prescribed by regulatory bodies. Results show that the Sylhet sand may pose a significant radiation hazard to the dwellers via prolonged exposure, and necessary precautionary steps need to be taken to ensure safe dwellings while using this sand for construction and decorative purposes.