抄録
In a natural aerated zone, infiltrated water flows discontinuously because of repeated cycles of rainfall and evaporation. In order to study migration behavior of radionuclides in the aerated zone, migration experiment of 60Co was carried out by a column method, in which deionized water was fed intermittently into sandy soil layer contaminated with 60Co.
The 60Co concentration in the deeper soil layer increased when the times of flow interrup-tion increased. It is very likely that this was attributed to the increase of movable {60Co(OH)2}n which was formed by pH-rise in the interstitial water during the interrupted period due to buffer action of the soil. A filtration model was developed and was found to be adapted to the concentration distribution of {60Co(OH)2}n fraction ; the amount of {60Co(OH)2}, , was esti-mated. It was concluded that about 1% of sorbed cationic 60Co was changed to {60Co(OH)2}n by one time of the interruption.
