CS-137-MIGRATION IN SOILS AND ITS TRANSFER TO ROE DEER IN AN AUSTRIANFOREST STAND

The depth distribution of Cs-137 in an Austrian spruce forest stand wa s investigated in soil profiles sampled in thin layers (2 cm) and in p ooled soil samples over an area of 200 ha. The Cs-137 concentrations b oth from Chernobyl and global fallout decrease exponentially with dept h. Forty-six percent of Chernobyl-derived caesium and 26% from global fallout are still to be found in the litter layer; <3% (for global fal lout 6%) have reached layers deeper than 20 cm of mineral soil. Correl ation analysis showed a significant dependence of Cs-137 content in sa mples on organic matter as well as cation exchange capacity. Using a c ompartment model, average residence half-times of 5.3, 9.9, 1.78 and 0 .8 years were calculated for the layers litter, 0-5 (Ah(1)), 5-10 (Ah( 2)) and 10-20 cm (A/B) of mineral soil, respectively. Using the model predictions of soil contamination as a basis and considering the roe d eer forage plants' rooting depths, the development of Cs-137 contamina tion of roe deer (Capreolus capreolus) (1987-1993) was well described by applying an aggregated transfer factor.