Measurement Ratio of 226Ra/228Ra in Marine Samples Using The Cation Exchange Resin and Gross α/β Spectrometry

Abstract

A method for determine activity of ²²⁶Ra and ²²⁸Ra in seawater samples by Gross α/β spectrometry was developed, where the Ba(Ra) was purified using a cation exchange resin column in warm temperature (70ºC). The Ba(Ra)SO₄ salts were wrapped on the plastic disc and counted using the gross α/β spectrometry after remain standing for three months. In order to certify the validation of this method, sediment reference materials have been analyzed and provided a good agreement between the analytical results and recommended values with the recovery values of 105.2 and 108.5% for ²²⁶Ra and ²²⁸Ra, respectively. This radiochemical procedure was also applied on the marine environment samples collected from Pulau Redang, Terengganu, such as seawater and suspended particulate matter. The analytical results for ²²⁶Ra and ²²⁸Ra in seawater were varied from 2.08 ± 0.19 mBq L^-1 to 12.43 ± 0.47 mBq L^-1 and 5.92 ± 0.93 mBq L^-1 to 33.53 ± 2.03 mBq L^-1, respectively. Meanwhile, the activities of ²²⁶Ra and ²²⁸Ra in suspended particulate matter were also varied in the range of 4.32 ± 0.37 Bq g^-1 to10.29 ± 0.59 Bq g^-1 and 5.12 ± 0.46 Bq g^-1 to 9.82 ± 0.47 Bq g^-1, respectively.