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This study investigates the naturally occurring radionuclides in Egyptian black sands collected from the Mediterranean Sea Coast, an area rich in sediments from the White Nile, Blue Nile, and Atbara rivers. The black sands mainly comprise two groups of minerals: the gangue group, consisting of quartz, feldspar, amphiboles, pyroxenes, epidote, and micas, and the economic minerals group, which includes magnetite, garnet, zircon, monazite, and uncommon commercial minerals like thorite. A gamma spectrometry with a NaI (Tl) detector was employed to analyze black sand samples for the presence of radionuclides. Additionally, radium equivalent activities (Raeq), absorbed dose rate, annual effective dose, gamma radiation hazard index (Iγ), external hazard index, internal hazard index (Hin), and lifetime cancer risk (ELCR) were calculated based on the measured activity concentrations of 226Ra, 232Th, and 40K. This comprehensive analysis contributes valuable insights into the radiological properties and potential hazards associated with Egyptian black sands. Due to the significant radioactive risk associated with these black sand samples, specifically in the Mediterranean Sea Alexandria coastal area, must be considered while using them as building materials. Measured values include Ra-226 (56 Bq/kg), Th-232 (77 Bq/kg), and K-40 (55 Bq/kg). [ABSTRACT FROM AUTHOR]

This study was carried out to evaluate the distribution of naturally occurring radioactive materials (NORM) and radiological risk indexes in aerosol dust in Nicosia, Cyprus utilizing a high-resolution HPGe gamma-spectrometry. The activity concentrations of 226Ra, 232Th, and 40K in the selected aerosol dust samples ranged from 25.9–52.4, 21.7–46.3, to 471–1302 Bq kg−1, respectively. The average activity concentrations of 40K were found to be above the Earth's crust average. The internal and external hazard indexes are well below the acceptable limit in most dust samples. All investigated samples met the exemption dose limit of 0.3 mSv y−1. [ABSTRACT FROM AUTHOR]

The blocking effect of 222Rn gas and its progeny by various face masks has been determined using a measurement system with a parallel AlphaGUARD detector. The theoretical approach of diffusion rate for different particle sizes was calculated. The filtering effect of the different masks followed the order N99 > surgical > N95 > double cloth > double cellulose > cloth > cellulose masks, respectively. Overall the blocking effect percentage ranged between 7.65 and 22.66%. The study indicated that the effect of a mask with high quality in filtering the gas of 222Rn and its decay products is more than the double-layer masks. [ABSTRACT FROM AUTHOR]