Natural and artificial radioactivity distribution in soil of Fars province, Iran

Fars province is a large populated large province located in the southwest of Iran. This work presents a study of natural and radioactivity levels in soil samples of this province. For this purpose, 126 samples were gathered from different regions of the province and analysed by gamma spectroscopy to quantify radioactivity concentrations of radionuclides using a high-purity germanium detector and spectroscopy system. The results of this investigation show the average concentrations of 271 +/- 28 Bq kg(-1), 6.37 +/- 0.5 Bq kg(-1), 14.9 +/- 0.9 Bq kg(-1) and 26.3 +/- 1.9 Bq kg(-1) for K-40, Cs-137, Th-232 and U-238 in soil, respectively. Finally, baseline maps were established for the concentrations of each of the radionuclides in different regions. The absorbed dose rate and the annual effective dose (AED) were also calculated for the radionuclides according to the guidelines of UNSCEAR 2000. The average AED from the radioactivity content of soil in this province was found to be 39.9 +/- 1.8 mu Sv.