Behavior of Cs in surface soil

The degrees of movement for toxic substances in soil have been mostly evaluated as a distribution ratio expressed with a solid liquid concentration ratio or a distribution coefficient. However, most of these data were obtained from laboratory experiments and so, it seems necessary to collect data of the distribution ratio under the conditions of natural fields. Surface soil and pore water were collected at several points around a refinery to characterize them and the distributions of Cs, Co, Cr and Zn in soil and pore water were investigated. Cs concentrations in the solid phase of the soil samples were 7-10 mg/kg and there were almost no differences in Cs concentration among horizontal and vertical positions. Cs distribution in the soil samples were different among the soils at different points. The solid liquid distribution ratio of Cs was about 102 L/kg in the soil from a farm. The value was present within the previously reported range of 100-104 L/kg. (M.N.)