137Cs soil to plant transfer factors derived from pot experiments and field studies

Soil to plant transfer factors (TF) of 137Cs for different crop plants were determined in pot experiments, in outdoor experiments with plastic containers of 50 L volume and in field studies. In all cases the soil contamination with 137Cs resulted from fallout after the Chernobyl reactor accident. Mean TF derived for outdoor plants on a fresh weight basis ranged from 0.0017 (leaf vegetables) to 0.059 (rye straw) and showed characteristic differences, depending on the plant part and species. Generally, for fruits and potato tubers, lower TF were found than for vegetative plant parts. Moreover, the data were compared with those from experiments carried out before the Chernobyl accident. There is a good agreement for cereals (with the exception of rye), fruits, vegetables and fodder crops, while actual TF are substantially lower for potatoes and leaf and root vegetables, but higher for rye. A significant negative correlation was observed between the TF and the soil activity concentrations for 137Cs. In container experiments the TF were found to be influenced mainly by the clay content of the soil. (author). 11 refs, 2 figs, 2 tabs