2019 Fiscal Year Final Research Report
Evaluation on activities of radiocesium released by the FNPP1 accident damaged by The Great East Japan Earthquake. - preliminary study using stranded odontoceti -
| Project/Area Number |
17K00642
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Environmental risk control and evaluation
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| Research Institution | National Museum of Nature and Science, Tokyo |
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Principal Investigator |
TAJIMA YUKO 独立行政法人国立科学博物館, 動物研究部, 研究主幹 (00450635)
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| Co-Investigator(Kenkyū-buntansha) |
和田 敏裕 福島大学, 環境放射能研究所, 准教授 (90505562)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Keywords | 放射性物質 / セシウム / ストランディング / 鯨類 / 福島原発 / 東日本大震災 / イルカ / クジラ |
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| Outline of Final Research Achievements |
Radiocesium (134Cs and 137Cs) activity concentrations in muscle tissues of 26 stranded toothed whales including some as the cotrols were measured to assess the radiocesium contamination in marine mammals after the FNPP1 accident caused by the GEJEarthquake on 11 March 2011. 137Cs (half-life: 30.1 y) were detected from 23 whales collected 134-2185 days after the FNPP1 accident at 111-845 km far from the FNPP1. Of these, 134Cs (half-life: 2.06 y) were detected from 9 finless porpoises. One of them collected in December 2011 from Sammu City, 210 km south from the FNPP1, showed a high total Cs of 1620 Bq/kg-wet. 137Cs was not detected in the testes of 4 whales using electron-prove X-ray microanalysis. Some of the thyroid grand showed fibrosis and follicular adenoma. The results demonstrated radiocesium released from the FNPP1 was bio-accumulated in toothed whales, although almost all the values were under the Japanese food safety level.
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| Free Research Field |
海棲哺乳類学、保全医学
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| Academic Significance and Societal Importance of the Research Achievements |
東日本大震災時に福島原発から流出した放射性物質の海洋生物の被曝状況とリスク評価を漂着鯨類を用いて体系的アプローチを実施した。放射性セシウムCs-137（半減期30.1年）が22個体、Cs-134（半減期2.06年）が9個体から検出され、特に沿岸性スナメリで高値を示した。これは、福島原発由来の放射性セシウムが野生鯨類に蓄積していることが示され、その値が経年的に低下してたこともこれを支持し、その実効生態学的半減期は338日数と算出された。
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