Determination of Ra-226 in produced water by liquid scintillation counting

摘要

It is proposed a method for the determination of Ra-226 in offshore platform liquid effluent samples (produced water). The method is based on a two-phase liquid scintillation counting system and allows for the direct and simple determination of Ra-226 content. Samples with high barium content may also have high Ra-226 concentration. Therefore, the sample volume is based on the barium concentration and ranges from 10 mL to 100 mL. Our new method was tested using multiple real samples and was compared with the BaSO4 precipitation method. The results based on the LSC were 30% higher than the precipitation method, which is attributed to the self-absorption of alpha particles in the BaSO4 precipitate. The determination of both Ra-226 and Ra-228 in the liquid effluent of offshore oil platforms is mandatory in Brazil. Thus, a second method of accurately assessing Ra-228 content remains necessary. (C) 2016 Published by Elsevier Ltd.