Greenhouse pot experiments were carried out to study the mobility of U and Th
in soil and the bioavailability of these radionuclides to two widely cultivated plants
(wheat and rye). The purpose of this research was to estimate an ability of the crops to accumulate U and Th, thus removing these metals from contaminated soil. Rye and wheat grown in radionuclide enriched soils demonstrated a significant increase in concentrations of U and Th in the roots of both these plants. Th was less available for plant uptake than U. The ratios of radionuclide concentrations in roots of the plants grown in contaminated soil to those in roots of the control plants were 45 (U) and 25 (Th). Despite such a significant increase of radionuclide concentrations in the plants, the U content in the soils decreased by only two times, and the Th concentration in the contaminated soils remained unchanged. No transfer of U and Th to plant leaves was detected in any of the plants. As a result of soil contamination at trace levels, wheat and rye were able to accumulate U and Th in the roots but were unable to translocate these radionuclides to leaves at measurable concentrations.