The radioecological model ECOSYS: concept and applications

The radioecological model ECOSYS-87 has been developed to estimate the transfer of radionuclides in food chains, and to assess the human radiation exposure via all relevant pathways after a short term contamination of the environment. This paper describes the main modelling approaches used, and it gives some examples of the model's applications. Especially the dependence of the ingestion dose on the time of the year when the deposition occurs is discussed. This seasonality effect differs considerably if the model is adapted to different regions with different climatological and agricultural conditions. Validation exercises have shown that the model is able to give quite good predictions of the contamination of foodstuffs in general, provided that an appropriate adaptation to the radioecological conditions of the considered region has been made. But also a few points have been detected in the validation studies which have to be improved in the future. Examples of them, as e.g. the modelling of fruit from perennial trees, or foodstuffs from natural or semi-natural environments, are discussed. (author)