How Can the Reliability of Radioecological Assessment Models Be Improved?

INTRODUCTION Assessment models are widely used to estimate the radiation exposure originating from routine or accidental releases of radionuclides into the environment. The major criterion for their quality is the reliability of their results. In this context reliability means that the results of model calculations are in fairly good agreement with the expected or observed contamination of the environment, thus yielding reliable estimates of the dose to man. Reliable results of assessment models are essential for radioecological impact statements, estimates of dose due to annual releases and estimates of dose in the case of accidental releases. Radioecological models consist of three components: the model structure itself, i.e. number and types of compartments and their interrelations, the radioecological parameters, like transfer factors, deposition velocity, etc., and the assumptions on the living habits of man and agricultural practices. The aim of the paper is to point out conceptual sources of uncertainties and give some ideas how these uncertainties could be reduced.