Soil radioactivity levels and radiation exposure to the population in Aswan and Abu Simbel areas, South of Egypt

Abstract

Gamma-ray spectrometer and Lucas cell were used to evaluate the activity concentrations of 226Ra, 232Th, 40K, and 222Rn mass exhalation rates for 37 topsoil samples from different sites in Aswan city, Aswan-Abu Simbel highway, and Abu Simbel village, south of Egypt. The average activity concentration of 226Ra, 232Th, and 40K was 23.3 ± 1.7, 21.1 ± 1.2, and 283.4 ± 22.3; 21.2 ± 1.7, 15.2 ± 1.0, and 89.4 ± 10.5; 29.0 ± 2.2, 26.3 ± 1.5, and 79.5 ± 9.7 Bq kg−1 for soil from Aswan city; Aswan-Abu Simbel highway; and Abu Simbel village, respectively. Activity ratios for the studied radionuclides were calculated, and 232Th/226Ra ratios in most of the sampling sites were <1.1 (natural equilibrium ratio). The mass ratio of Th/K was computed, and the results showed the presence of three main types of clay minerals (montmorillonite, kaolinite, and heavy thorium-bearing minerals) in the studied areas. Radon measurements showed that soil from Aswan city has the highest average value of 222Rn mass exhalation rate (20.6 ± 1.7 mBq kg−1 h−1). The ambient dose equivalent rates were measured in situ using the portable survey meter, and the obtained values showed no significant differences between the studied areas. In general, the results indicate that the studied areas can be considered as areas with normal background radiation levels, and therefore the risks of exposure to natural radiation are minimal.