Evaluation of Concentration of Natural Radioactive Materials in the Soil of Malakal Town

Abstract

This study is on the natural environmental radiation, which aims to find the concentrations of Natural Occurring Radioactive Materials (NORMs) in the soil of Malakal Town, using two different techniques (X- Ray Fluorescence (XRF) and Spectral Core Gamma (SCG)). The results obtained using XRF technique have given the concentrations averages of K-40 to 1.033 ppm and its highest concentration in one of the sites have been found to be 1.3ppm which gives activity of 406.9 Bq/Kg and this is with in the world averages, this accurate result could be attributed to the fact that K-40 photons are considerably to have less energies to be absorbed by Fe atoms, as Fe has high abundance concentrations in Malakal soil, and relatively lager different energy levels between their atomic levels. The averages concentrations of U and Th, obtained by (SCG) technique are 0.66, 2.29 in ppm for U,andTh respectively, with activity of 8.194 and 10.42 for U and Th respectively. And that results are below the world averages, which can be attributed to the fact that the high concentrations of Fe in addition to, the existence of radioactive related elements such as Zr,Sr,Ti, and Pb shown by XRF, proved the low concentrations of these two elements U, Th, as they have decayed in to their kits and daughters. This result indicates the reliability of XRF technique and the acceptance of these results. In this work, the average activities of (NORMs) were calculated to be 164.67 Bq/Kg and the annual doses for indoors were 0.082mSv/yr, and 0.02 mSv/yr for outdoors.