The use of Chernobyl fallout data to test model predictions of the transfer of 131I and 137Cs from the atmosphere through agricultural food chains

This paper highlights the results of a recent international model validation study (BIOMOVS/A4) that has collected data during the aftermath of the Chernobyl accident from 13 sites around the Northern Hemisphere. Models commonly used in the USA for regulatory assessments tended to overpredict by amounts that often approached and/or exceeded a factor of ten. Large overestimation was usually the result of compound conservatism employed in a model at numerous stages. In some cases, seemingly accurate predictions were the result of compensatory error. The study also revealed that similar models produced different results when operated by different users, and that accuracy was affected more frequently by the choice of parameter values than by differences in structural complexity. 4 refs., 3 figs