Determination of uranium, thorium and potassium activity concentrations in soil cores in Araba valley, Jordan

Soil samples were collected from six different locations in Araba valley, situated between Aqaba port and Dead sea. The samples have been analysed by using gamma-ray spectrometry. From the measured gamma-ray spectra, activity concentrations are determined for U-238, Th-232 and K-40. The mean activity concentration for U-238, Th-232 and K-40 was found to be in the range 19 +/- 1.4 to 38.7 +/- 3, 14.3 +/- 0.8 to 35 +/- 3.2 and 94 +/- 18.9 to 762 +/- 47.4 Bq kg(-1), respectively. These results indicate that the mean concentrations of U-238, Th-232 and K-40 in the populated Araba valley are lower than those in other populated areas. On the other hand, the concentrations of the major oxides (Al2O3, SiO2, K2O, CaO and Fe2O3) in the samples were determined using wavelength dispersive X-ray fluorescence. High potassium and iron content in some samples might be attributed to the active faults, which refer to the Dead sea transform fault.