Here are presented results of studies on vertical and horizontal migration of strontium ⁹⁰Sr isotope in soil systems of Bug river valleys. Mean radioactivity of strontium in these soils was 26.15 ± 22.2 Bq/kg. Atmospheric precipitation of strontium on this area was 0.35 kBq/m²/cm. Radioactivity in soil profiles ranged from 17 to 130 Bq/m²/cm and the isotope was detected even at 30 cm depth. Some tendency to vertical migration of strontium towards the river was noticed. Obtained results were compared with concentrations of calcium and strontium in the soil. Any clear influence of these elements on the migration of strontium ⁹⁰Sr was noticed.