Modeling of sorption kinetics of Cs, Am and Pu to sediments of the Baltic Sea

Modeling of sorption parameters and knowledge about sorption mechanisms of Cs, Pu and Am are required for quantification of their redistribution, for better understanding sorption processes and for their validation as a particular tool for tracer studies. Sorption mechanisms of Cs, Pu and Am were studied in the natural seawater - sediment systems using data obtained from field observations, kinetic tracer experiments, speciation analyses. Despite the similar sorption mechanisms of Cs, Am and Pu, elucidated by modeling, the speciation analyses showed rather different Cs, Am and Pu bonding to bottom sediments and redistribution of Pu redox speciation. This can lead to the different sorption behavior of Pu under oxic and anoxic conditions and can result in variations of ^239,240Pu/¹³⁷Cs activity ratio.