Effective migration velocity of137Cs and90Sr as a function of the type of soils in Belarus

The effective migration velocities of137Cs and90Sr in typical soils of the Khoiniki district, Gomel region, Belarus, were evaluated. In most of these soils, the migration rate of90Sr seems higher than that of137Cs and ranges from 0.71 to 1.54 cm/year and 0.39 to 1.16 cm/year, respectively. In some soil types both radionuclides have the same speed, approximately 1 cm/ year. Seven years after the accident the main part of the residual radionuclides is located in the upper 10 cm of soils. At a depth of 50–70 cm the quantity of radionuclides is very small. The obtained results on vertical migration of the radionuclides as a function of the soil type are presented in the form of a radioecological map for the whole contaminated region of Khoiniki.