Comparison of transfer of technetium and rhenium in radish plants from nutrient solution

A radiotracer experiment was carried out to compare the plant uptake behaviors of technetium (Tc) and rhenium (Re) from nutrient solution. Radish samples, grown in nutrition culture for about a month in a green house, were transferred into plastic vessels containing nutrient solutions contaminated with multitracer solution including Tc-95m and Re-183. The activities in nutrient solutions and oven-dried plant parts (roots, fleshy roots and leaves) were measured with Ge detecting systems. The concentrations of Tc-95m and Re-183 in the nutrient solutions after harvesting the plants were almost the same with those in the initial solution. Presumably, the radionuclides were taken up with water through plant roots. The distributions of Tc and Re in the plants showed no differences, thus, soluble Tc and Re absorption behaviors by plant samples were the same. Behaviors of other elements were different from those of Tc and Re. These findings point to the possible use of Re as the chemical analogue of Tc in soil solution to plant uptake experiments. (author)