Dynamics of Chernobyl-fallout radionuclides in soil solutions of forest ecosystems

The long-term dynamics of radionuclides in soil solutions of various subhorizons of litter and mineral layer of soddypodzolic sandy forest soils at 30-km zone aroudn Chernobyl nuclear power station was studied. One year after the accident the relative contents of 90Sr. 106Ru. 134,137Cs. 144Ce in soil solutions (radionuclide fractions in the liquid phase of soil) for the whole contaminated layer of soil were very low (0.034 – 3.5%) and varied from one plot of zone to another because of unequal physico-chemical properties of nuclear deposition. By 1989 this parameter for radiocesium decreased 5–9 times and then varied slightly. The data indicate that since the accident three processes have taken place: radiocesium transfer from fallout into soluble forms, its migration down the soil profile and fixation of radionuclide in organic-mineral layer of soil under the forest litter.