Adaptation of ECOSYS for Nordic food chain modelling

The ECOSYS model is the basic food chain model in the current European state-of-the-art systems for decision-aiding in connection with major nuclear accidents. To apply this model optimally in the decision process in a Nordic country contaminated due to an accident, it is necessary to change a number of the default parameters in ECOSYS to reflect Nordic, national or regional conditions. A number of potentially problematic parameters are identified and examined in this context. The importance of obtaining adequate parameters for, e.g., human consumption habits, animal feeding regimes, crop development dynamics and soil-plant transfer processes are discussed. Also the generic importance of considering particle size in connection with deposition modelling is demonstrated. (au)