著者

坂口 綾 門倉 彰伸 Peter STEIER 山本 政儀 坂田 昂平 富田 純平 高橋 嘉夫

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.11, pp.1001-1012, 2013-11-05 (Released:2013-12-05)

参考文献数

38

被引用文献数

2 1

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これまで,目的元素の濃縮・精製技術の向上や分析機器の開発など,分析化学分野の進展は,環境放射能そのものの研究やそれを活かした研究に多大なる影響を与え,分野拡大やその躍進に大きく貢献してきた.本論文では,近年の分析・測定技術の発展に伴い測定可能となってきた環境中の人工放射性ウラン(U)同位体である236Uに着目した研究について報告する.ここでは特に,地球表層環境にある236Uの起源や濃度,蓄積量についてセシウム(Cs)-137の分布などと共に詳細に調べた結果に加え,明らかになった236Uの特性を活かした地球科学的研究への応用例として,海水循環トレーサー利用に関して日本海をフィールドとした研究についても紹介する.

著者

AYA SAKAGUCHI AKINOBU KADOKURA PETER STEIER KAZUYA TANAKA YOSHIO TAKAHASHI HARUKA CHIGA AKIHITO MATSUSHIMA SATORU NAKASHIMA YUICHI ONDA

出版者

GEOCHEMICAL SOCIETY OF JAPAN

雑誌

GEOCHEMICAL JOURNAL (ISSN:00167002)

巻号頁・発行日

vol.46, no.4, pp.355-360, 2012-08-20 (Released:2013-11-08)

参考文献数

26

被引用文献数

90 27

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Concentrations of the radionuclides, U, Pu, and Cs were measured in water samples (10-20 L) to study analyte dispersion and migration following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. A total of 8 water samples including oceanic water and paddy-field water were collected in the vicinity of the plant. Determinations of U, Pu and Cs isotopes were performed by accelerator mass spectrometry (AMS), inductively coupled plasma mass spectrometry (ICP-MS), and γ-ray spectrometry. The 236U/238U atom ratio was in the range 1.83-8.20 × 10-9 for fresh water and around 0.57 × 10-9 for seawater while the concentration of 236U was about 104-105 and 106 atoms/kg, respectively. Plutonium (239,240Pu) was detected in one riverine sample and the marine samples at very low levels and with large uncertainty. The concentrations of 137Cs in fresh riverine samples were 0.02-0.46 Bq/kg which are more than three orders of magnitude larger than the global fallout level. As for seawater samples within 80 km offshore of the FDNPP, the concentrations of 137Cs were 10-20 times higher than that of the Japan Sea water. Also 134Cs and 137Cs were of similar concentrations in all samples. The results show that volatile and refractory nuclides such as Cs, U and Pu exist in the dissolved phase, which can be readily assimilated by plants/humans. However the environmental impact of Pu and U in the vicinity of the FDNPP is considered to be low in comparison to that of the volatile radionuclide Cs.