Mechanisms of cesium transfer in forest ecosystems obtained from continuous monitoring of roedeer contamination

At a roedeer population from a prealpine forest are (1600 km2) periodic contamination maxima in autumn, a slow overall decrease with an effective ecological half-time of 2,6 +/- 0,4 years and a regional pattern with characteristic small-scale variations representing the transfer of Cs radionuclides from the soil to the animals are 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 theses radionuclides. This is corroborated by observations in a highmoor, where the shape of the depth distribution and the transfer to plants turned out to be rather similar to those of forest soils and at fertilized forest areas; where the transfer factor was significantly reduced. (author)