DETERMINATION OF THE PHYSICOCHEMICAL PARAMETERS WHICH INFLUENCE THE CS AVAILABILITY IN FOREST SOILS

The type of soil and humus has to be considered as primordial for the evaluation of the Cs availability and for its transfer dynamics. Previ ous studies on the radiocesium distribution through a forest soil prof ile indicate that the intermediate layer, OAh (organic and mineral par ticles intimately mixed) accumulates Cs in a more efficient way than t he deeper mineral layer. Our study on the physico-chemical parameters influencing Cs retention shows however, that humic compounds do not pa rticularly influence the Cs retention. On the contrary, the K interact ion with mineral particles induces a clear increase in the Cs fixation . This observation suggests that K inducing collapse is responsible fo r a higher Cs retention. In the OAh layer, an original collapsed state of the mica structure would benefit the Cs fixation.