A preliminary report on the determination of natural radioactivity levels of the State of Qatar using high-resolution gamma-ray spectrometry

This study is aimed at the determination of the activity concentrations of naturally occuring and technically enhanced levels of radiation in soil samples collected across the landscape of Qatar. Representative soil samples from various locations across the Qatarian peninsula have been collected and analyzed in order to establish activity concentrations associated with the (235,8)U and (232)Th natural decay chains and also the long-lived naturally occurring radionuclide (40)K. The activity concentrations have been measured using a hyper-pure germanium detector. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented, together with the preliminary values of the activity concentrations associated with the naturally occuring radionuclide chains for six soil samples collected from the Qatarian peninsula. Sample 228, which has been collected from an inshore oil-field area, was observed to have the highest observed value of (226)Ra concentration among the six samples. The weighted mean values of the activity concentrations of the radionuclides (238)U, (232)Th and (40)K in one particular sample (sample 228) were, respectively, found to be 213.9 +/- 1.4, 4.55 +/- 0.11 and 111.4 +/- 3.6 Bq/kg, which compare with the worldwide weighted mean values in soil samples, 33,45 and 420 Bq/kg, respectively. The deduced activity concentration of (238)U in sample 228 in the current work was found to be significantly higher than the worldwide average value and was also significantly higher than the values determined for the five other initial samples discussed here. The mean values of the activity concentration of the (232)Th series, (40)K and (137)Cs in Bq/kg from the six investigated soil samples were found to be 9.4 +/- 1.3, 204 +/- 22 and 5.8 +/- 5.6, respectively, with the quoted uncertainty referring to the standard deviation among these measurements. (C) 2009 Elsevier B.V. All rights reserved.