Analysis of radioactivity levels and hazard assessment of black sand samples from Rashid area, Egypt

Abstract

Abstract The aim of this study is to evaluate the radioactivity levels and radiological impacts of representative black sand samples collected from different locations in the Rashid area, Egypt. These samples were prepared and then analyzed using the high-resolution gamma ray spectroscopy technique with a high-purity germanium detector. The activity concentration ( A c ), minimum detectable activity, absorbed gamma dose rate, external hazard index ( H ex ), annual effective dose rate equivalent, radium equivalent, as well as external and internal hazard index ( H ex and H in , respectively) were estimated based on the measured radionuclide concentration of the 238 U( 226 Ra) and 232 Th decay chains and 40 K. The activity concentrations of the 238 U, 232 Th decay series and 40 K of these samples varied from 45.11 ± 3.1 Bq/kg to 252.38 ± 34.3 Bq/kg, from 64.65 ± 6.1 Bq/kg to 579.84 ± 53.1 Bq/kg, and from 403.36 ± 20.8 Bq/kg to 527.47 ± 23.1 Bq/kg, respectively. The activity concentration of 232 Th in Sample 1 has the highest value compared to the other samples; this value is also higher than the worldwide mean range as reported by UNSCEAR 2000. The total absorbed gamma dose rate and the annual effective dose for these samples were found to vary from 81.19 nGy/h to 497.81 nGy/h and from 99.86 μSv/y to 612.31 μSv/y, which are higher than the world average values of 59 nGy/h and 70 μSv/y, respectively. The H ex values were also calculated to be 3.02, 0.47, 0.63, 0.87, 0.87, 0.51 and 0.91. It was found that the calculated value of H ex for Sample 1 is significantly higher than the international acceptable limit of