Radioecological model for radiocesium in shallow lakes

A general assessment model for shallow lakes is reported. The model predicts the dynamics of 137 Cs in lake water, sediment and fish. The model takes into consideration the presence of fuel particles from Chernobyl fallout. In the food chain model we added the assumption that the bioaccumulation factor is experimentally available for equilibrium conditions, at known temperatures while the loss rate is proportional with the uptake rate. Site specific parameter distributions are used when available and the most important parameters are investigated through ranks of standardized regression coefficients. The most important parameters are the suspended matter concentration, the variable fraction of the fallout of the sedimentation rate. After one year from the accident the dynamical water contamination is mainly due to the distribution coefficient, the re-suspension fraction, the sedimentation rate and the catchment. When compared the experimental data, the model predictions appear to be rather good, as the 137 Cs concentrations in lake water is concerned. Also good predictions relative to cesium concentration in non-predatory fish were obtained, while for predatory fish a slight under-prediction is obtained. The time evolution of sediment concentration is also under-predicted by a few times