Georadiological Assessment and Radiological Hazard Mapping of Uranium-Enriched Formations in El Sheikh Soliman Area, Southwestern Sinai, Egypt

High-resolution georadiological assessment of 66 stratigraphically and lithologically varied rock samples from El Sheikh Soliman region (selected as the area of ground magnetic survey) was performed using gamma-ray spectrometry and multivariate statistical tools. The concentrations and distribution of natural radionuclides 238U, 238Ra, 232Th, and 40K were measured, and the associated radiological hazards were evaluated. The activity levels of 238U ranged from 45.1 to 1073.2 Bq/kg (mean = 316.4 Bq/kg), with peak values in ferruginous siltstones (Um Bogma formation), organic-rich shales (Adedia formation), and micaceous shales (Abu Hamata formation). Over 70% of samples exhibited uranium-series disequilibrium (U/Ra >1.5), suggesting recent uranium remobilization under oxidizing-suboxic conditions. Radiological indices such as radium equivalent activity (Raeq), absorbed dose rate (Dr), and annual effective dose equivalent (AEDE) indicated that 36% of samples exceeded the Raeq safety limit of 370 Bq/kg, and 41% surpassed the global AEDE average (0.07 mSv/year), with strong correlations (r > 0.85) between 238U and hazard indicators. Although 232Th concentrations were lower (22.4–186.1 Bq/kg), significant contributions were found in felsic and metavolcanic rocks due to accessory minerals like monazite and zircon. The 40K levels (54.3–1420.5 Bq/kg) were higher in granitic and clay-rich samples containing K-feldspar and muscovite. While 232Th and 40K posed lower direct risks, their cumulative effects influenced Raeq and Hex indices. Principal component analysis explained 87.3% of total variance, with uranium being the dominant factor. Hierarchical cluster analysis revealed four geochemically distinct groups, reflecting variations in lithology, mineralogy, and redox behavior. The study highlights the value of integrating radiometric and statistical data for effective radiological hazard mapping and environmental monitoring in uranium-rich arid zones.