2021 Fiscal Year Final Research Report
High resolution analysis of fallout records of radioactive iodine and chlorine in ice core from both poles
| Project/Area Number |
19H04252
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 63010:Environmental dynamic analysis-related
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| Research Institution | The University of Tokyo |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
堀内 一穂 弘前大学, 理工学研究科, 准教授 (00344614)
本山 秀明 国立極地研究所, 研究教育系, 教授 (20210099)
笹 公和 筑波大学, 数理物質系, 准教授 (20312796)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | ヨウ素129 / 塩素36 / 加速器質量分析 / アイスコア / 大気圏核実験 / 核燃料再処理 |
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| Outline of Final Research Achievements |
Time course profiles of Chlorine-36 in Greenland SE dome ice core and Iodine-129 in Antarctic ice core were obtained and compared with Iodine-129 profile of Greenland. A prominent peak was observed in 1950's in the Chlorine-36 profile corresponding to the atmospheric weapons testing conducted on the marine environment. The bomb testing peaks were observed both in the Iodine-129 profiles of Greenland and Antarctic, however an enhancement due to the operation of spent-nuclear fuel reprocessing was observe only in the Greenland but Antarctic. These knowledges are significant for the construction of standards time course profiles of the anthropogenic Chlorine-36 and Iodine-129.
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| Free Research Field |
加速器質量分析，同位体地球化学
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| Academic Significance and Societal Importance of the Research Achievements |
ヨウ素の長寿命放射性同位体，ヨウ素129（半減期1570万年）と塩素の長寿命放射性同位体，塩素36（半減期30.1万年）は，主に人為起源の放射性同位体であり，大気圏内核実験や再処理工場あるいは原子力事故などから環境中に放出される．これらの核種は，様々な環境動態研究に用いられる．ヨウ素129は地殻内物質移動や生物地球化学的循環のトレーサーとして利用される．また，塩素36は地下水の年代マーカーとして有用な核種である．本研究の成果は，ヨウ素129及び塩素36の大気フォールアウトの過去数十年間にわたる記録の復元を与えるものであり，これらの核種を利用する応用研究により高い精度を付与するものとなる．
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