Terrestrial gamma radioactivity levels and their corresponding extent exposure of environmental samples from Wadi El Assuity protective area, Assuit, Upper Egypt

Representative environmental samples (sandy soil, limestone, marble and gravels) collected from Wadi El Assuity, protective area, Assuit governorate in Upper Egypt have been investigated radiometrically using NaI (Tl) gamma-ray spectrometer. The specific activity of the radionuclides in Bq kg⁻¹ for soil ranged between 10.5 and 18.7 for ²²⁶Ra, 1.5 to 4.6 for ²³²Th and from 94 to 107 for ⁴⁰K, for limestone ranged between 19 and 27.1 for ²²⁶Ra, 32.9 to 50 for ²³²Th and from 49 to 7 3 for ⁴⁰K, where, for marble ranged between 12.2 and 30.7 for ²²⁶Ra, 32.6 to 59.5 for ²³²Th and 55 to 70 for ⁴⁰K and for gravels ranged between 7.8 and 21.8 for ²²⁶Ra, 19.8 to 30.0 for ²³²Th and from 151 to 260 for ⁴⁰K. The mean activity concentrations of measured radionuclides were compared with other literature values. The absorbed dose rate, radium equivalent activity and external hazard index were calculated and compared with internationally recommended values. The gamma absorbed dose rates in the samples ranged between 8.44 and 50.89 nGy h⁻¹. These dose rates are consistent with the accepted worldwide average 55 nGy h⁻¹ for the public. All values obtained for radium equivalent activity are < 370 Bq kg⁻¹, which are acceptable for safe use. The calculated values of external hazard index obtained varied from 0.12 to 0.24. Since these values are lower than unity, one can say that the radiation hazard is insignificant for the population living in the investigated area. This permits the use of these materials sediments as building materials in any probable development projects at this area.