Assessment of Natural Radioactivity Levels and Radiological Hazard Indices in Soil Samples Collected from the Central Region of Saudi Arabia

The activity levels of 226 Ra, 232 Th, and 40 K in 38 soil samples collected from four areas (Al Assyah, Buraidah, Al Shamassea, and Al Badayyia) in Qassim (Saudi Arabia) were determined by γ-ray spectrometry with a NaI(Tl) detector. The activity concentrations of 226 Ra, 232 Th, and 40 K varied from 9.6 ± 0.2 to 158.6 ± 0.1, from 9.6 ± 0.1 to 110.0 ± 0.4, and from 70.1 ± 0.5 to 390.3 ± 1.5 Bq/kg, respectively. Also, the annual effective dose rate was estimated to assess the health hazards caused by the external exposure to people living in these regions. The concentrations of 40 K and 232 Th are lower than the world average, whereas the 226 Ra concentration is higher than the recommended level detailed by UNSCEAR.