New information on radionuclides concentration in phosphorites originating from Tunisia and Algeria
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ORIGINAL PAPER
New information on radionuclides concentration in phosphorites originating from Tunisia and Algeria Jaloul Bejaoui & Mohamed Samaali & Souad Baccouche & Nafaa Regugui & Mohamed Fethi Ben Hamouda & Zohra Azzouz & Adel Trabelsi & Salah Bouhlel & Boulamia Salim
Received: 1 October 2011 / Accepted: 8 February 2012 / Published online: 21 February 2012 # Saudi Society for Geosciences 2012
Abstract In this study we investigate the radiological hazard of naturally occurring radioactive material in Tunisian and Algerian phosphorite deposits. Eight samples of phosphorite were collected from the phosphorite mines. The Tunisian and Algerian phosphorites occur in the Late Paleocene and Lower Eocene (Ypresian-Lutetian) in age (Béji Sassi 1984 and Zaïer 1999). Activity concentrations in all the samples were measured by alpha spectrometry and gamma spectrometry. Alpha spectrometry analyses show that the specific activity values of 238 U, 234U and 235U in the samples of Tunisian phosphorite were 327±7 (321–327), 326±6 (325–331) and 14.50±0.72 (13.90–15.57) Bq kg−1, respectively. Specific activity measured by gamma spectrometry in the samples of the Tunisian and Algerian phosphorite shows a small difference. Specific activity levels of 40K, 226Ra, 232Th, 235U and 238U in the phosphorite samples from Tunisia were, respectively, 71.10± J. Bejaoui (*) : M. Samaali : S. Baccouche : N. Regugui : M. F. B. Hamouda : Z. Azzouz : A. Trabelsi UR-MDTN, Centre National des Sciences et Technologies Nucléaires, Tunis, Tunisia e-mail: [email protected] B. Salim Département de géologie et d’Aménagement, Faculté des sciences et sciences de la nature et de la vie, Université de Tébessa, Tébessa, Algeria J. Bejaoui : S. Bouhlel Lab Biotechnologie & Valorisation des Bio-Géo Ressources, Institut Supérieur de Biotechnologie de Sidi Thabet, Université de la Manouba, Ariana 2020, Tunisia S. Bouhlel Département de Géologie, Faculté des Sciences de Tunis, Université de Tunis el Manar, Ariana 2092, Tunisia
3.80, 391.54±9.39, 60.38±3.74, 12.72±0.54 and 527.42± 49.57 Bq kg−1 and Algeria were 15.72±1.73, 989.65±12.52, 12.08±1.20, 47.50±1.52 and 1,148.78±7.30 Bq kg−1, respectively. The measured value of specific activity of 232Th and 40K in the Tunisian phosphorite samples is relatively higher than that found in the samples of Algerian phosphorite. The measured activity of uranium (238U) in the Tunisian phosphorite (527±49) Bq kg−1 is lower than in Algerian phosphorite. The measured activity of 238U in the Tunisian phosphorite samples was (527–1,315±65) 238U Bq kg−1 which is higher than its maximum background value of 110 Bq kg−1 in soils of the various countries of the world (Tufail et al. Radiat Meas 41:443–451, 2006). Different geological origins of phosphorites deposits are the main reason for the large spread in worldwide specific activities. The obtained results of uranium concentrations in phosphorites of different types (Algerian and Tunisian) demonstrate that the uranium concentrations are mainly governed by the phosphatic material. Th
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