An experimental study of the time dependence of uptake from soil of 137Cs, 106Ru, 144Ce and 99Tc into green vegetables, wheat and potatoes

In this study the experimental data were analysed using the CEGB's dynamic foodchain model, and were used to validate the relevant part of the model structure, to produce model-specific input data and to identify possible future improvements to the model structure. The root uptake of the specified radionuclides was studied and the concentration levels measured. The data were analysed using a simplified version of the general model. The compartment system incorporated within the model was shown to be capable of reproducing the data for 137Cs, 106Ru and 144Ce to an extent sufficient to justify its use in ingestion radiological dose assessments, but to be less successful in fitting the 99Tc data. The analysis resulted in the production of a well validated set of model-specific input data relevant to UK conditions and agricultural practice differing significantly from values obtained from global literature surveys. Possible future improvements to the model structure were also identified, aimed at providing improved estimates of crop contamination levels for timescales in excess of those considered in this study. (U.K.)