Fate of plutonium derived from the atomic bomb detonated at Nagasaki, Japan

Iwata, Hajime*; Sakamaki, Keiko*; Yasuda, Kenichiro   ; Onuki, Toshihiko; Utsunomiya, Satoshi*

The aim of this study is to understand the fate of plutonium derived from atomic bomb, which has been preserved in the bottom sediment for 60 years, based on the investigation of the speciation and size distribution of plutonium. Approximately 60 % of plutonium is present as bound to organic matters and 30 % is present as insoluble species such as Pu oxides. Our results also suggest that the fast transformation of plutonium to the species bound to the organic matter for the period of 60 years, evidencing the important role of the natural organic matters on the plutonium speciation in the environment.