title: Release of Pu isotopes from the Fukushima Daiichi Nuclear Power Plant accident to the marine environment was negligible.
abstract: Atmospheric deposition of Pu isotopes from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident has been observed in the terrestrial environment around the FDNPP site; however, their deposition in the marine environment has not been studied. The possible contamination of Pu in the marine environment has attracted great scientific and public concern. To fully understand this possible contamination of Pu isotopes from the FDNPP accident to the marine environment, we collected marine sediment core samples within the 30 km zone around the FDNPP site in the western North Pacific about two years after the accident. Pu isotopes ((239)Pu, (240)Pu, and (241)Pu) and radiocesium isotopes ((134)Cs and (137)Cs) in the samples were determined. The high activities of radiocesium and the (134)Cs/(137)Cs activity ratios with values around 1 (decay corrected to 15 March 2011) suggested that these samples were contaminated by the FDNPP accident-released radionuclides. However, the activities of (239+240)Pu and (241)Pu were low compared with the background level before the FDNPP accident. The Pu atom ratios ((240)Pu/(239)Pu and (241)Pu/(239)Pu) suggested that global fallout and the pacific proving ground (PPG) close-in fallout are the main sources for Pu contamination in the marine sediments. As Pu isotopes are particle-reactive and they can be easily incorporated with the marine sediments, we concluded that the release of Pu isotopes from the FDNPP accident to the marine environment was negligible.
authors: Research Center of Radiation Protection, National Institute of Radiological Sciences , Anagawa 4-9-1, Inage, Chiba 263-8555, Japan.
authors: Wenting
authors: W
authors: Bu
authors: Miho
authors: M
authors: Fukuda
authors: Jian
authors: J
authors: Zheng
authors: Tatsuo
authors: T
authors: Aono
authors: Takashi
authors: T
authors: Ishimaru
authors: Jota
authors: J
authors: Kanda
authors: Guosheng
authors: G
authors: Yang
authors: Keiko
authors: K
authors: Tagami
authors: Shigeo
authors: S
authors: Uchida
authors: Qiuju
authors: Q
authors: Guo
authors: Masatoshi
authors: M
authors: Yamada
mesh_terms: D002588:Cesium Radioisotopes / Q000032:analysis; D062406:Fukushima Nuclear Accident; D019015:Geologic Sediments / Q000032:analysis*; D011005:Plutonium / Q000032:analysis*; D011834:Radiation Monitoring; D012623:Seawater; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D002588:Cesium Radioisotopes; D014875:Water Pollutants, Radioactive; D011005:Plutonium