title: Effects of the nuclear disaster on marine products in Fukushima.
abstract: After the release of huge amounts of radionuclides into the ocean from the devastated Fukushima Dai-ichi Nuclear Power Plant (FDNPP), safety concerns have arisen for marine products in Fukushima Prefecture. As of October 2012, we had inspected the radionuclide ((131)I, (134)Cs and (137)Cs) concentrations in 6462 specimens within 169 marine species collected off the coast of Fukushima Prefecture from April 2011. Only two species exceeded the Japanese provisional regulatory limit for (131)I (2000 Bq/kg-wet) immediately after the FDNPP accident. In 2011 and 2012, 63 and 41 species respectively exceeded the Japanese regulatory limit for radioactive Cs (100 Bq/kg-wet). The overall radioactive Cs concentrations of the total marine products have decreased significantly. However, the time-series trends of radioactive Cs concentrations have differed greatly among taxa, habitats (pelagic/demersal), and spatial distributions. Higher concentrations were observed in shallower waters south of the FDNPP. Radioactive Cs concentrations decreased quickly or were below detection limits in pelagic fishes and some invertebrates, and decreased constantly in seaweed, surf clams, and other organisms. However, in some coastal demersal fishes, the declining trend was much more gradual, and concentrations above the regulatory limit have been detected frequently, indicating continued uptake of radioactive Cs through the benthic food web. The main continuing source of radioactive Cs to the benthic food web is expected to be the radioactive Cs-containing detritus in sediment. Trial fishing operations for several selected species without radioactive Cs contamination were commenced in Soma area, 50 km north of the FDNPP, from June 2012. Long-term and careful monitoring of marine products in the waters off Fukushima Prefecture, especially around the FDNPP, is necessary to restart the coastal fishery reliably and to prevent harmful rumors in the future.
authors.affiliation: Soma Branch, Fukushima Prefectural Fisheries Experimental Station, Soma, Fukshima 9760022, Japan. wada385@yahoo.co.jp
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Wada
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Nemoto
authors.forename: Shinya
authors.initials: S
authors.lastname: Shimamura
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Fujita
authors.forename: Takuji
authors.initials: T
authors.lastname: Mizuno
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Sohtome
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Kamiyama
authors.forename: Takami
authors.initials: T
authors.lastname: Morita
authors.forename: Satoshi
authors.initials: S
authors.lastname: Igarashi
mesh_terms: D000818:Animals; D002588:Cesium Radioisotopes / Q000032:analysis*; D005399:Fishes; D005506:Food Contamination / Q000032:analysis*; D062406:Fukushima Nuclear Accident; D007448:Invertebrates; D007457:Iodine Radioisotopes / Q000032:analysis*; D011834:Radiation Monitoring; D017747:Seafood / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D002588:Cesium Radioisotopes; D007457:Iodine Radioisotopes; D014875:Water Pollutants, Radioactive
keywords: (131)I; (134)Cs and (137)Cs; Ecological half-life; Fukushima; Marine products; Nuclear accident