Migration of 85Sr and 137Cs in vertical soil profiles

Vertical distribution of Sr-85 and Cs-137 in undisturbed single-contaminated agricultural soils was studied in laboratory conditions during their irrigation with wet atmospheric precipitation in dependence on time for about one year. The soil samples were collected from several sites in the surroundings of the Dukovany and Jaslovske Bohunice nuclear power plants using a special auger. The samples were placed into polyethylene columns. The activity of radionuclides in the soil profiles after their separation into single layers was determined with a Ge(Li) semiconductor gamma spectrometer. Based on the exponential depth distribution of radionuclides, the values of their migration parameters as such the relaxation depth, migration rate and retardation factor were calculated. The effect of the permanent grass cover and of zeolite on the migration parameters of the two radionuclides was also investigated