Microbial impacts on the migration of actinides; Effects of exudates on the migration

Onuki, Toshihiko; Ozaki, Takuo; Yoshida, Takahiro*; Nankawa, Takuya ; Kozai, Naofumi   ; Sakamoto, Fuminori  ; Suzuki, Yoshinori*; Francis, A. J.

We have been conducting basic studies on the microbial accumulation of actinides in order to understand the environmental behavior of actinides under relevant conditions. The effect of bacterial exudates on the sorption of Eu(III) and Cm(III) by Chlorella vulgaris was studied by a batch method. The pH dependence of log Kd of Eu(III) and Cm(III) for cellulose, major component of C. vulgaris cell, differed from that for C. vulgaris. However, thelog Kd of Eu(III) and Cm(III) for cellulose in the solution containing exudates from C. vulgaris cells in a 0.5% NaCl solution showed a similar pH dependence to that by C. vulgaris. These results suggests that exudates affect on the sorption of Eu(III) and Cm(III) on C. vulgaris.