量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum and Radiological Science and Technology.
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Tecchnetium-99 (99Tc) is a fission product of 235U and 239Pu with a relatively high yield of about 6%. The half-life of this radionuclide is 2.1 * 10^5 years, implying its presence in the environment for many generations. The main sources of 99Tc in the environment are nuclear weapons testing and nuclear fuel reprocessing plants.
In aerobic conditions, Tc is present as pertechnetate (TcO4-), which is both highly soluble and mobile in the environment. It acts as a sulfate analog and assimilation of TcO4- by plants raises concern about the transfer of 99Tc to human though agricultural plants. We previously reported that Tc in agricultural soil surface water would transform from soluble TcO4- to insoluble form (> 0.2 um in size). It is difficult for the plant to take in the insoluble Tc in this size.
The formation of insoluble Tc in the soil surface waters seems to be caused by microorganisms. In this study we describe kinds of microbes contribute to the insoluble Tc.
Contribution of bacteria on the insoluble technetium formation in paddy soil surface water
