Concentrations of ⁹⁰Sr and ¹³⁷Cs/⁹⁰Sr activity ratios in marine fishes after the Fukushima Dai-ichi Nuclear Power Plant accident

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• 作者：Shizuho Miki ; Ken Fujimoto ; Yuya Shigenobu ; Daisuke Ambe ; Hideki Kaeriyama ; Kaori Takagi ; Tsuneo Ono ; Tomowo Watanabe ; Hiroya Sugisaki and Takami Morita
• 刊名：Fisheries Oceanography
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：26
• 期：2
• 页码：221-233
• 全文大小：526K
• ISSN：1365-2419

文摘

Strontium-90 (⁹⁰Sr) was released together with radioactive cesium (Cs) from the Fukushima Dai-ichi Nuclear Power Plant (FNPP) accident. Although the total amount of ⁹⁰Sr released into the marine environment from the FNPP was estimated to be a factor of 100 lower than that of ¹³⁷Cs, the public have been concerned about the safety of commercial species because of the tendency of accumulation in bones of organisms, its long physical half-life and less information about ⁹⁰Sr concentrations in commercial species. In this study, we investigated the concentrations of ⁹⁰Sr in marine fishes off Japan before and after the FNPP accident. Except for within a 20-km radius from the FNPP, ⁹⁰Sr concentrations higher than the background level (<0.046 Bq kg⁻¹ wet) were only detected in 4 of 26 specimens collected off Fukushima. Furthermore, ⁹⁰Sr concentrations in all samples collected outside of Fukushima were under the detection limit (<0.040 Bq kg⁻¹ wet). Also, the concentrations of ⁹⁰Sr in marine fishes were notably lower than those of ¹³⁷Cs, and thus the activity ratios of ¹³⁷Cs to ⁹⁰Sr in the whole body of teleost fishes were 5–190 times higher than that of before the accident. The activity ratio tended to decrease owing to a decrease in the ¹³⁷Cs concentration in marine fish. Our result together with ananalysis of other data sets indicated that the influence of the FNPP accident on ⁹⁰Sr in marine fishes was limited to the area near the FNPP and outside of the FNPP harbor area can be considered as negligible.