Accumulation and potential dissolution of Chernobyl-derived radionuclides in river bottom sediments

Sanada, Yukihisa*   ; Matsunaga, Takeshi; Yanase, Nobuyuki; Nagao, Seiya; Amano, Hikaru; Takada, Hideshige*; Tkachenko, Y.*

Areas contaminated with radionuclides from the Chernobyl nuclear accident have been identified in Pripyat River near the Chernobyl Nuclear Power Plant. The bottom sediments contained Cs (10 - 10 Bq/m) within 0-30 cm depth, which is comparable to the ground soil of in the vicinity of the nuclear power plant (the Exclusion Zone). The sediments also accumulated Sr (10 Bq/m ), Pu (10 Bq/m ), Am (10 Bq/m ) derived from the accident.The comparison of these inventories with those of the released radionuclides at the accident and the experimental analysis using the selective sequential extraction of the radionuclides in the sediments suggest that the potential mobility of Cs and Pu is low compared with Sr in the bottom sediment, while the potential dissolution of Sr from the river bottom sediment should be taken into account with respect to the long-term radiological influence on the aquatic environment.