著者

添盛 晃久 小豆川 勝見 野川 憲夫 桧垣 正吾 松尾 基之

出版者

公益社団法人 日本分析化学会

雑誌

分析化学 (ISSN:05251931)

巻号頁・発行日

vol.62, no.12, pp.1079-1086, 2013-12-05 (Released:2013-12-28)

参考文献数

34

被引用文献数

2 5

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The concentration of radioactive cesium in sediments of Tokyo-bay, released by the Fukushima Dai-ichi nuclear power station accident, was measured every half year from July ’10 to February ’13 in order to analyze the trend of concentration. The samples were collected at two artificial deeper sites in dredged trenches and one natural shallower site, which were located off Makuhari in Tokyo-bay, then they were brought into a Ge detector to measure the γ-rays. According to an analysis of the upper layer of the samples, both 134Cs and 137Cs had been detected since the samples of August ’11, and they must have been released by the accident. Furthermore, from February ’12 to February ’13, the concentrations of 134Cs and 137Cs in upper layer of sediments had been higher at deeper sites than shallower site. The deeper sites look like pitfall traps for fine particles clinging to 134Cs and 137Cs, so we can call these sites "the hotspot in the sea". We also examined the depth profiles of 134Cs and 137Cs in samples taken on August ’12 and February ’13. As a result, 134Cs and 137Cs were found to have gone deeper in the sediment on February ’13 than on August ’12, and the inventory of them was also larger on February ’13. In addition, this phenomenon was observed more clearly at deeper sites than shallower site. Though 134Cs and 137Cs had not increased very much in upper layer from August ’12 to February ’13, we clarified that they had been flowing into the Tokyo-bay.

著者

添盛 晃久 小豆川 勝見 山形 武広 野川 憲夫 松尾 基之

出版者

一般社団法人日本地球化学会

雑誌

日本地球化学会年会要旨集 2012年度日本地球化学会第59回年会講演要旨集

巻号頁・発行日

pp.319, 2012 (Released:2012-09-01)

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福島第一原発事故に伴う影響のうち、海洋汚染の状況や収束見通しの解明に寄与するために、本研究では東京湾幕張沖を研究の対象とし、事故以前から現在まで我々のグループが継続的に同一地点で採取していた底質試料に対し、放射性セシウムの濃度変化を分析した。分析の結果、事故後時間が経過するにつれて濃度が増加していることが認められ、東京湾では河川による流入の影響が海流による拡散の影響よりも強く、放射性物質が蓄積しやすい環境になっていると考えた。また、深堀では平場よりも高濃度となる傾向も確認でき、深堀が一種のホットスポット的役割を果たしていることが示唆された。