title: Radiological impact of TEPCO's Fukushima Dai-ichi Nuclear Power Plant accident on invertebrates in the coastal benthic food web.
abstract: Radioactive cesium ((134)Cs and (137)Cs) concentrations in invertebrates of benthic food web (10 taxonomic classes with 46 identified families) collected from wide areas off Fukushima Prefecture (3-500 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 (137)Cs concentrations within detected data were often found in areas near or south of the FDNPP, which is consistent with the reported spatial distribution of (137)Cs concentrations in highly contaminated seawater and sediments after the FDNPP accident. Overall (137)Cs concentrations in invertebrates, the maxima of which (290 Bq kg(-1)-wet in the sea urchin Glyptocidaris 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 Malacostraca 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 (137)Cs 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.
authors.affiliation: Fukushima Prefectural Fisheries Experimental Station, Iwaki, Fukushima 9700316, Japan.
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Sohtome
authors.affiliation: Soma Branch, Fukushima Prefectural Fisheries Experimental Station, Soma, Fukushima 9760022, Japan. Electronic address: wada385@yahoo.co.jp.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Wada
authors.affiliation: Fukushima Prefectural Fisheries Experimental Station, Iwaki, Fukushima 9700316, Japan.
authors.forename: Takuji
authors.initials: T
authors.lastname: Mizuno
authors.affiliation: Fisheries Office of Fukushima Prefectural Government, Iwaki, Fukushima 9708026, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Nemoto
authors.affiliation: Fukushima Prefectural Fisheries Experimental Station, Iwaki, Fukushima 9700316, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Igarashi
authors.affiliation: University of Fukui, Faculty of Medical Sciences, Yoshida-gun, Fukui 9101193, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nishimune
authors.affiliation: National Institute of Radiological Sciences, Chiba, Chiba 2638555, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Aono
authors.affiliation: Tokyo University of Marine Science and Technology, Minato-ku, Tokyo 1088477, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Ito
authors.affiliation: Tokyo University of Marine Science and Technology, Minato-ku, Tokyo 1088477, Japan.
authors.forename: Jota
authors.initials: J
authors.lastname: Kanda
authors.affiliation: Tokyo University of Marine Science and Technology, Minato-ku, Tokyo 1088477, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishimaru
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000528:radiation effects; D002588:Cesium Radioisotopes / Q000032:analysis / Q000378:metabolism*; D020387:Food Chain; D062406:Fukushima Nuclear Accident; D007448:Invertebrates / Q000528:radiation effects*; D010140:Pacific Ocean; D011834:Radiation Monitoring; D012621:Seasons; D014875:Water Pollutants, Radioactive / Q000032:analysis / Q000378:metabolism*
chemical_list: D002588:Cesium Radioisotopes; D014875:Water Pollutants, Radioactive
keywords: Benthic invertebrates; Ecological half-life; Fukushima; Nuclear power plant accident; Radioactive cesium