TERRAPUB Geochemical Journal

Geochemical Journal, Vol. 51 (No. 2), pp. 193-197, 2017


Novel method for low level Sr-90 activity detection in seawater by combining oxalate precipitation and chelating resin extraction

Hirofumi Tazoe,1* Hajime Obata,2 Masatoshi Tomita,3 Shinya Namura,3 Jun Nishioka,4 Takeyasu Yamagata,5 Zin'ichi Karube6 and Masatoshi Yamada1

1Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan
2Atmosphere and Ocean Research Institute, The Tokyo University, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8564, Japan
3Environmental Engineering Department, The General Enviromental Technos Co., Ltd., 3-1-1, Higashi-kuraji, Katano, Osaka 576-0061, Japan
4Pan-Okhotsuk Research Centor, Institute of Low Temperature Science, Hokkaido University, N19 W8, Kita-ku, Sapporo 060-0819, Japan
5College of Humanities and Sciences, Nihon University, 3-25-40, Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan
6Center for Water Environment Studies, Ibaraki University, 1375, Ohu, Itako, Ibaraki 311-2402, Japan

(Received May 5, 2016; Accepted August 23, 2016)

Abstract: 90Sr released into seawater from nuclear bomb testing and nuclear facility accident sites requires long-term monitoring. However, measuring 90Sr in seawater is still difficult and time-consuming. This study is aimed at improving the preconcentration method for successive purification using DGA Resin chromatography, which is applied to 90Sr analysis in seawater. At natural pH, the oxalate coprecipitation technique effectively collected Sr (84% in Sr yield) from seawater without Mg or Na. For 90Sr determination, 90Y in secular equilibrium with 90Sr was directly extracted using Fe coprecipitation and DGA Resin chromatography. The proposed method simplifies the analytical processes associated with the conventional method. Analytical results for surface seawater in the western North Pacific (0.81 ± 0.06 Bq m-3, n = 5) were consistent with those obtained using the conventional method (0.81 ± 0.07 Bq m-3, n = 5).
Key words: strontium-90, nuclear power plant, seawater monitoring, preconcentration, oxalate precipitation

*Corresponding author E-mail: tazoe@hirosaki-u.ac.jp

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