Participation in IAEA Proficiency Test to Analyse Cobalt, Strontium and Caesium in Seawater Using Direct Counting and Radiochemical Techniques

Radiation monitoring in the environment and foodstuffs is one of the main responsibilities of Office of Atoms for Peace (OAP) as the nuclear regulatory body of Thailand. The main goal of the OAP is to assure the safety of the Thai people and environment from any radiological incidents. Various radioanalytical methods have been developed to monitor radiation and radionuclides in the environmental and foodstuff samples. To validate our analytical performance, several proficiency test exercises from the International Atomic Energy Agency (IAEA) have been performed. Here, the results of a proficiency test exercise referred to as the Proficiency Test for Tritium, Cobalt, Strontium and Caesium Isotopes in Seawater 2017 (IAEA-RML-2017-01) are presented. All radionuclides excepting ³H were analysed using various radioanalytical methods, i.e. direct gamma-ray counting for determining ⁶⁰Co, ¹³⁴Cs and ¹³⁷Cs and developed radiochemical techniques for analysing ¹³⁴Cs, ¹³⁷Cs using AMP pre-concentration technique and 90Sr using di-(2-ethylhexyl) phosphoric acid (HDEHP) liquid extraction technique. The analysis results were submitted to IAEA. All results passed IAEA criteria, i.e. accuracy, precision and trueness and obtained ‘Accepted’ statuses. These confirm the data quality from the OAP environmental radiation laboratory to monitor radiation in the environment.





References:
[1] B. Salbu and O. C. Lind, Integr. Environ. Assess. Manag., vol. 12, pp. 687-689, 2016.
[2] A. V. Harms, I. Osvath and D. Osborn, IAEA-RML-2017-01 Proficiency Test for Determination of Radionuclides in Seawater. Vienna: International Atomic Energy Agency, 2018.
[3] K. Hirose, M. Aoyama, Y. Igarashi and K. Komura, J. Radioanal. Nucl. Ch., vol. 276, pp. 795-798, 2008.
[4] N. Phaopeng, The Measurement of Cs-137 Radioactivity in Seawater and the Oyster (Crassostrea belcheri) from the lower Gulf of Thailand for Radiation Dose Assessment in the General Public. Bangkok: Kasetsart University, 2013.
[5] W. J. Major, K. D. Lee and R. A. Wessman, EarthPlanet. Sci. Lett, vol. 16, pp. 138-140, 1972.
[6] R. Fukai, G. Statham and K. Asara, Rapp. Comm. Intern. MerM6dit., vol. 23, 1976.
[7] J. Borcherding and H. Nies, J RadioanalNucl Chem., vol. 98, pp.127-131, 1986.
[8] J. Suomela, L. Wallberg, and J. Melin, Method for Determination of Strontium-90 in Food and Environmental Samples by Cherenkov Counting. Stockholm: Swedish Radiation Protection Institute, 1993.
[9] H. H. Ross, Theory an Application of Cherenkov Counting, Liquid Scintillation Science and Technology. New York: Academic Press Inc., 1976.
[10] A. Shakhashiro, U. Sanaone, A. Trinkl, M. Makarewicz, A. C. Yonezawa, C. K. Kim, G. Kis-Benedek, T. Benesch and R. Schorn, Report on the IAEA-CU-2006-04 ALMERA Proficiency Test on the Determination of Gamma Emitting radionuclides, IAEA/AL/170. Vienna: International Atomic Energy Agency, 2007.
[11] M. K. Pham, I. Osvath and J. Sanchez-Cabeza, Proficiency Test Determination of Radionuclides in Fish Flesh Samples IAEA/AQ/13. Vienna: International Atomic Energy Agency, 2010.