TRANSFER PROCESSES OF CESIUM RADIONUCLIDE S IN FOREST ECOSYSTEMS OBSERVED AT A ROEDEER POPULATION

In the prealpine region of Oberschwaben in south-west Germany a compar atively high contamination of roedeer (capreolus capreolus) with Cesiu m radionuclides was observed as a consequence of soil contamination fr om the Chernobyl fallout, which decreases only slowly with an ecologic al half-time of 2.6 +/- 0.4 years. From an almost complete surveillanc e of roedeer contamination in an area of 1600 km2 since autumn 1967 di stinct seasonal and regional pattern were obtained. The regional varia tion of transfer from soil to roedeer and from soil to plants has been investigated in the largest forest (100 km2) of this region (Altdorfe r Wald) and a significant reduction of the transfer in a forest area t reated with a fertilizer consisting of 83% lime prior to the Chernobyl accident was observed. The depth distribution of Cs radionuclides in the layered forest soil is peaked in the uppermost humic layer and it is inferred that binding to organic substances plays an important role in the fixation of those radionuclides.