Factors have been examined which influence the radionuclides sorption from soil particles by fluid imitating rumen liquid of the cattle. It is noted that the extent of extractability of 137Cs from soil is influenced mainly by presence of potassium ions in modelling liquid. Major factor influencing the release of 90Sr from soil is pH value of the medium. The presence of heavy metals salts affected the release of radionuclides from soil particles. The data observed make it possible to use the modelling solutions to predict bioavailability of radionuclides from soil as well as to predict possible contamination of animal products (milk and meat).