A review of transfer factors for assessing the dose from radionuclides in agricultural products

The dose to man from radionuclides released to the environment is generally assessed with mathematical models that require transfer factors as input parameters to predict the concentration of radionuclides in foodstuffs. This article summarizes recent attempts to review the worldwide literature and derive updated transfer factors to predict concentrations of radionuclides in terrestrial foods using equilibrium models. Updated transfer coefficients to predict the concentration of a radionuclide in cow's milk and other animal products from that in feed are presented as well as concentration factors to predict the concentration of a nuclide in a food or feed crop from that in soil. Comparing the updated transfer coefficients with those in existing tables leads to suggested changes in the transfer coefficients for milk and beef. Soil-to-plant concentration factors are extremely variable, which limits the usefulness of a single concentration factor to predict the uptake of a radionuclide into crops from soil. The potentially large uncertainty associated with predicting the uptake of radionuclides by plants from soil at a particular location may be reduced by considering the dominant crops and soil types in the area and how various soil properties affect the concentration factor. The updated transfer factors may be useful inmore » assessing transport through terrestrial food chains when site-specific information is not available. In addition, they provide a basis for systematically updating existing tables of transfer factors for generic assessments.« less