Aging effects of the availability of strontium and cesium to plants

To determine the effects of long-term radionuclide residence in soil on plant uptake patterns, barley was grown in pots containing aged (90Sr and 137Cs) and freshly added (85Sr and 134Cs) radionuclides. Uptake rates indicated that the plants took up more of the nuclides in a freshly mixed nuclide/soil matrix; uptake rates declined after 30-60 days, or apparently as the matrix approached equilibrium. Strontium uptake was accelerated in the early part of the plant's life cycle while cesium uptake was nearly uniform throughout. Aging of 90Sr and 137Cs in soils for 25 and 17 yr. respectively, did not greatly change radionuclide availability to plants. (author)