Radioactivity of ^{238}U, ^{232}Th, ^{40}K, and ^{137}Cs and assessment of depleted uranium in soil of the Musandam Peninsula, Sultanate of Oman


Abstract: ^{238}U, ^{232}Th, ^{40}K, and ^{137}Cs radioactivities were determined in soil samples collected from the Musandam Peninsula, Sultanate of Oman, using a high resolution gamma-ray spectroscopy system. In addition, total uranium was measured in selected soil samples by inductively coupled plasma optical emission spectroscopy (ICP-OES). The averages of radioactivity levels in the soil for ^{238}U, ^{232}Th, and ^{40}K were 14.42 Bq kg^{-1}, 9.95 Bq kg^{-1}, 158.21 Bq kg^{-1}, and 2770 Bq m^{-2} for ^{137}Cs, respectively. The mean of the total uranium in soils was 1578.28 \mu g kg^{-1}. As the mean values, radium equivalent was estimated to be 40.84 Bq kg^{-1} and annual effective outdoor radiation dose was 25.4 \mu Sv. The contributions of individual radionuclides for ^{238}U, ^{232}Th, ^{40}K, and ^{137}Cs to the total annual effective dose were 30%, 32%, 32%, and 6% respectively. Selected soil samples were also investigated for depleted uranium (DU) by estimating the percentages of ^{235}U in total uranium and the results revealed that DU concentrations matched its range in natural uranium.

Keywords: Soil, Oman, uranium, cesium-137, radium-226, thorium-232, potassium-40

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