Validation of the BCR sequential extraction procedure for natural radionuclides

• Published in: Chemosphere (Oxford) Vol. 198; pp. 397 - 408
• Main Authors: Pérez-Moreno, S.M., Gázquez, M.J., Pérez-López, R., Bolivar, J.P.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2018
• Subjects: BCR sequential extraction; BCR-701; Mobility; Natural radionuclides; Speciation; Mobility; BCR-701; Natural radionuclides; BCR sequential extraction; Speciation
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2018.01.108

Determining the availability of natural radionuclides in environmental conditions is increasingly important in order to evaluate their toxicity. A validated procedure is necessary to ensure the comparability and accuracy of the results obtained by different laboratories. For that, an optimised BCR sequential extraction procedure has been applied to the certified reference material (CRM), coded as BCR-701, and their resulting liquid and solid fractions were subjected to an exhaustive chemical and radioactivity characterisation. In this sense, several material characterisation techniques were used for chemical, mineralogical, and radioactive characterisation, in order to gain basic information about the obtained fractions. In accordance with the results of this work, the BCR sequential extraction procedure has been validated for the most significant alpha-emitter natural radionuclides (210Po, 234U, 238U, 230Th, 232Th, and 226Ra). It has been demonstrated that their mobility is related to the speciation under environmental conditions and the type of radionuclide; we have even found differences between radionuclides of the same element, such as the cases of the pairs 234U238U and 230Th232Th, for the BCR-701. In addition, we found that radium was mainly bound to the reducible fraction (Fe and Mn-oxyhydroxides), uranium to the oxidizable fraction (organic matter and sulphides), and that the polonium and thorium isotopes had a high affinity with the particulate phase (non-mobile fraction). •The mobility of natural radionuclides has been evaluated in BCR-701 by applying the BCR procedure.•The mobility of radionuclides is related to the speciation under environmental conditions and the type of radionuclide.•BCR-701 is proposed as a potential certified reference material for determining the mobility of natural radionuclides.