CHARACTERISTICS OF SR-90,CS-137 AND PU-239,PU-240 MIGRATION IN UNDISTURBED SOILS OF SOUTHERN BYELARUS AFTER THE CHERNOBYL ACCIDENT

Soil samples were taken from three sites representing typical undistur bed soils in southern part of Belarus contaminated with Chernobyl fall out. The activity of Sr-90, Cs-137 and Pu-239,Pu-240 in soil horizon 0 -20 cm were measured. The data obtained were used to evaluate compartm ent model parameters of radionuclide migration in soil layers at diffe rent depths. According to the results, the parameters of migration obt ained for various sites differ by more than a factor of two. The small est site averaged values of parameters were obtained for Pu-239,Pu-240 and the largest for Sr-90. The calculations show that in most cases, the migration rates of Sr-90 and Cs-137 tend to increase with increasi ng depth.