Radioactive and mineralogical assessment of mediterranean black sands: a systematic analysis and health risk evaluation

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 (Ra_eq), absorbed dose rate, annual effective dose, gamma radiation hazard index (I_γ), external hazard index, internal hazard index (H_in), 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).