⁹⁰Sr Analysis Method in the Marine Sediments

As an important product of the nuclear fission, ⁹⁰Sr is one of the enormously hazardous radionuclides to human and is also an important index of environmental radioactivity monitoring. Measuring ⁹⁰Sr activity has therefore become the attention of the monitoring task. We analyzed the activity of ⁹⁰Sr in the surface sediments near the Ningde power plant through determining its daughter product ⁹⁰Y by means of solvent extraction with bis-2-ethylhexyl phosphoric acid (HDEHP) in n-heptane. The interference of ²¹⁰Bi and Th can be separated efficiently by Bi₂S₃ precipitation, and Th can be separated from ⁹⁰Y using ion-exchange, respectively. Both the protocols give a decontamination factor over 10³. By following the decay curve of the samples, we observed a half-life of the nuclide of 64 h, consistent with that of ⁹⁰Y. The detection limit is 0.083 Bq/kg for this method. The activity of ⁹⁰Sr for 16 surface sediment samples near the Ningde power plant varies between 0.21-0.89 Bq/kg (dry mass). Overall, the procedure is fast and accurate, and can be applied to the determination of ⁹⁰Sr in the marine sediments.