Natural radioactivity in soil samples at the University of Kufa

Department of Physics, Faculty of Science, University of Kufa, 540011 Al-Najaf, Iraq

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Abstract

Humans are continuously exposed to environmental radioactivity from both natural and artificial radionuclides. Soil is one of the most significant contributors to terrestrial radioactivity. The purpose of this study is to determine the levels of natural radioactivity in radionuclide concentrations ²³⁸U, ²³²Th, and ⁴⁰K, as well as the radiological hazard factors, in soil samples collected from five faculties at the University of Kufa, Al-Najaf governorate, Iraq, using the gamma-ray spectroscopy. In the study area, the mean specific activities of ²³⁸U, ²³²Th, and ⁴⁰K, in Bq kg^-1 , were 12.72±4.82, 5.15±1.70, and 277.54±73.52, respectively. The mean values for various radiological risk indices – including the gamma exposure rate (X), external hazard (Hex), absorbed dose rate (D_r), annual effective dose equivalent (outdoor) (AEDE), and excess lifetime cancer risk (ELCR×10^-3) were 93.37±16.31 µR/h, 0.11±0.02, 20.56±3.56 nGy/h, 0.03±0.004 mSv/year, and 0.09±0.02, respectively. All measured specific activities and calculated radiological hazard indices were found to be below the corresponding world average values and recommended safety limits.