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 Science and Technology.
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Radioactive cesium (134Cs and 137Cs) concentrations in invertebrates of benthic food web (10 taxonomic classes with 46 identified families) collected from wide areas off Fukushima Prefecture (3e500 m depth) were inspected from July 2011, four months after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, to August 2013 to elucidate time-series trends among taxa and areas. Cesium-137 was detected in seven classes (77% of 592 specimens). Higher 137Cs concentrations within detected data were often found in areas near or south of the FDNPP, which is consistent with the reported spatial distribution of 137Cs concentrations in highly contaminated seawater and sediments after the FDNPP accident. Overall 137Cs concentrations in invertebrates, the maxima of which (290 Bq kg␣1-wet in the sea urchin Glyp- tocidaris crenularis) were lower than in many demersal fishes, had decreased exponentially with time, and exhibited taxon-specific decreasing trends. Concentrations in Bivalvia and Gastropoda decreased clearly with respective ecological half-lives of 188 d and 102 d. In contrast, decreasing trends in Mala- costraca and Polychaeta were more gradual, with longer respective ecological half-lives of 208 d and 487 d. Echinoidea showed no consistent trend, presumably because of effects of contaminated sediments taken into their digestive tract. Comparison of 137Cs concentrations in the invertebrates and those in seawater and sediments suggest that contaminated sediments are the major source of continuing contamination in benthic invertebrates, especially in Malacostraca and Polychaeta.