Radiological Characterization of Soil and Groundwater in a Granitic Terrain of Western Saudi Arabia: Implications for Drinking-Water Safety

This study presents a comprehensive radiological assessment of the Hada Al-Sham region in western Saudi Arabia, an area characterized by Uranium and Thorium-bearing granitic formations that may influence radionuclide distribution in groundwater. We systematically evaluated naturally occurring radioactive materials (NORM) in 20 environmental soil and groundwater samples using a High-Purity Germanium (HPGe) detector and ultra-low-level Liquid Scintillation Counter (LSC). Field measurements were conducted to establish background radiation dose rates across the region. Our results revealed that soil samples maintained activity concentrations substantially below international safety thresholds, with mean values of 221.07 Bq/kg for ⁴⁰ K and 9–11 Bq/kg for Uranium and Thorium series progeny. However, several groundwater samples exceeded regulatory limits for gross alpha (up to 1.15 Bq/L) and gross beta (up to 1.61 Bq/L) activities, indicating potential health risks from chronic exposure through drinking water ingestion. Field gamma measurements confirmed typical background radiation levels of 0.054 µSv/h for granitic terrains. These findings underscore the importance of routine radiological monitoring in geologically susceptible, groundwater-dependent communities to support evidence-based public health protection strategies aligned with IAEA and WHO guidelines.