Elucidation of the migration mechanism of radiocesium from sediment to benthic microalgae

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H04960
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Aquatic bioproduction science
• Research Institution: Tokyo University of Marine Science and Technology
• Principal Investigator: Arakawa Hisayuki 東京海洋大学, 学術研究院, 教授 (40242325)
• Co-Investigator(Kenkyū-buntansha): 鈴木 秀和 東京海洋大学, 学術研究院, 教授 (90432062)
• Research Collaborator: Okumura Yutaka ; Ikeda Yoshichika
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 放射性セシウム / 微細藻類 / 移行 / 底質 / 生態系

Outline of Final Research Achievements

It was examined quantitatively the radioactive Cs transferred from seabed sediments to ecosystems via benthic microalgae. First, the radioactive Cs concentration of benthic microalgae was very high compared to seawater, pore water and sediments. As the main transfer pathway of radioactive Cs of benthic microalgae, it was considered not from seawater and pore water but from sediment. Second, even if the species of microalgae changes seasonally, the concentration of radioactive Cs in benthic microalgae is stable and high, so the difference in uptake due to the species of microalgae was considered small. It was also succeeded in understanding the surface distribution of radioactive cesium in Matsukawaura. Third, we succeeded in estimating the amount of radioactive Cs uptake for small crustaceans.

Free Research Field

沿岸環境学

Academic Significance and Societal Importance of the Research Achievements

福島第一原発事故で汚染された環境や生物の中で現在もっとも放射性Cs濃度の高いものは、底質である。その濃度の低下に粒子に付着する微細藻類がどのくらい貢献するのか、また微細藻類へ移行した放射性Csは生態系へどのような影響を及ぼすのか検討した。底生微細藻類の放射性Cs濃度は他のものと比べて高く、底質からの移行があると考えられた。一方、海域における絶対量が小さいため、生態系への移行は限定的だと考えられた。これらの知見は、今後の福島沖の放射性Cs汚染の推移を理解するうえで重要である。