title: Characterization of Pu concentration and its isotopic composition in a reference fallout material.
abstract: Because there is no reference material for fallout plutonium isotope monitoring, preparation of such a material is necessary for quality control of fallout radionuclides analysis for atmospheric environmental studies. In this work, we report the characterization of Pu activity and its isotopic composition in a reference fallout material prepared by the Meteorological Research Institute (MRI), Japan. This material was prepared from samples collected at 14 stations throughout Japan in 1963-1979, with reference values of (137)Cs, (90)Sr and (239)(+)(240)Pu activities. We analyzed the activities of (239)(+)(240)Pu and (241)Pu, and the atom ratios of (240)Pu/(239)Pu and (241)Pu/(239)Pu using an isotope dilution sector-field inductively coupled plasma mass spectrometry (SF-ICP-MS). The (239)(+)(240)Pu activities in this fallout material using acid leaching and total digestion were 6.56+/-0.20 mBq/g and 6.79+/-0.16 mBq/g, respectively. Atom ratios of (240)Pu/(239)Pu were 0.1915+/-0.0030 and 0.1922+/-0.0044, respectively. Both (240)Pu/(239)Pu and (241)Pu/(239)Pu atom ratios were slightly higher than those of global fallout, which could be attributed to the deposition of fallout radionuclides resulting from the Chinese nuclear weapons tests conducted in the 1970s. The dominant host phases of (239)(+)(240)Pu were found to be organic matter-sulfides (70%) with a relative high (240)Pu/(239)Pu atom ratio, and Fe-Mn oxides (19%) using a sequential extraction method.
authors.affiliation: State Key Laboratory of Environmental Geochemistry, Chinese Academy of Sciences, Guanshui Road 46, Guiyang 550002, China.
authors.forename: Yongsan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Zheng
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Yamada
authors.forename: Fengchang
authors.initials: F
authors.lastname: Wu
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Katsumi
authors.initials: K
authors.lastname: Hirose
mesh_terms: D007564:Japan; D011005:Plutonium / Q000032:analysis* / Q000737:chemistry; D011834:Radiation Monitoring / Q000379:methods*; D011847:Radioactive Fallout / Q000032:analysis*; D011868:Radioisotopes; D012016:Reference Values
chemical_list: D011847:Radioactive Fallout; D011868:Radioisotopes; D011005:Plutonium