The dependence of natural radioactivity levels and its radiological hazards on the texture of agricultural soil in Upper Egypt

To control outdoor exposure to natural radiation, assessment of activity concentrations of the radionuclides in soils is substantial. In this paper, the activity concentration of natural radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K) was estimated for 174 agriculture soil samples using a sodium iodide detector (NaI) of (3” × 3”). Soil samples were collected from seven regions (56 locations) in EL-Minya governorate, Upper Egypt. The variability of natural activity concentration with soil’s textures was checked. The texture types of soil samples were silt clay loam, clay loam, sandy clay loam, and sandy silt loam. The obtained results indicate that the mean values of specific activity ranged from 11.3 ± 0.5 (sandy silt loam) to 21 ± 1(silt clay loam), 6.8 ± 0.3 (sandy silt loam) to 13.7 ± 0.7 (sandy clay loam), and 112 ± 5 (sandy silt loam) to 272 ± 13.6 (sandy clay loam) Bq kg⁻¹ for ²²⁶Ra, ²³²Th, and ⁴⁰ K, respectively. The obtained results were compared with the global average and tolerable limits as recommended in UNSCEAR 2008. On the other side, the radiological hazard resulting from the total natural radioactivity in the studied soil samples was estimated by different approaches. The obtained values were within the recommended safety limit and do not pose significant radiation hazards.