Uncertainty analysis in estimating Japanese ingestion of global fallout Cs-137 using health risk evaluation model

Abstract

Most of model estimation of the environmental contamination includes some uncertainty associated with the parameter uncertainty in the model. In this study, the uncertainty was analyzed in a model for evaluating the ingestion of radionuclide caused by the long-term global low-level radioactive contamination by using various uncertainty analysis methods : the percentile estimate, the robustness analysis and the fuzzy estimate. The model is mainly composed of five sub-models, which include their own uncertainty; we also analyzed the uncertainty. The major findings obtained in this study include that the possibility of the discrepancy between predicted value by the model simulation and the observed data is less than 10% ; the uncertainty of the predicted value is higher before 1950 and after 1980 ; the uncertainty of the predicted value can be reduced by decreasing the uncertainty of some environmental parameters in the model ; the reliability of the model can definitively depend on the following environmental factors : direct foliar absorption coefficient, transfer factor of radionuclide from stratosphere down to troposphere, residual rate by food processing and cooking, transfer factor of radionuclide in ocean and sedimentation in ocean.