Determination of natural radionuclides concentrations in surface soil in Tafila/Jordan

Abstract

A first comprehensive study is presented on natural radionuclide activity concentrations in surface soils in different divisions of Tafila city. The natural radioactivity of 238U, 232Th and 40K is determined using gamma spectroscopy. The soil activity concentrations ranged from 1.8 to 76.4 Bq kg -1 for 238U, 6.3 to 85.5 Bq kg -1 for 232Th, and 84 to 516.7 Bq kg -1 for 40K. The activity concentrations of the radionuclide in soils are directly relevant to outdoor exposure. Absorbed dose rates in air outdoors were calculated to be in the range of 22.28 - 62.71 nGy h -1 with an overall average value of 40.12 nGy h -1. The study showed an annual effective dose equivalent in the range of 27.34 - 76.96 μSv y -1. A comparison of the measured values with the corresponding worldwide average values shows that the activities of natural radionuclides in the studied samples are below the world average activity values.