CHARACTERISTICS AND TRANSFORMATION OF RADIOACTIVE CONTAMINATION OF SOILS OF BRYANSK-BELARUS POLESSYE

E. V. Kvasnikova, E. D. Stukin, G. I. Titkin, O. M. Zhukova, A. E. Samonov, E. N. Borisenko, E. D. Shagalova, and O. M. Zhukova

Based on field studies of the Bryansk-Belarus cesium spot 15 years after the CNPP accident, the present-day radionuclide composition of contamination has been estimated and it is shown that topographic-geochemical conditions of Polessye landscapes promote the spatial fixation of the 137Cs contamination spots. A technique is described for studying radionuclide migration using a principle of the landscape-geochemical profiling within small watersheds. It is shown that in meadow landscapes of marginal valley bogs there is some rise in contamination levels, with a noticeable increase in their variability, which is attributed to a slow-running process of radiocesium accumulation on the sorption-gley barrier. As of the summer of 2000, 90% of the 137Cs inventory in the soddy-podzolic sandy soils is concentrated in the upper 5—6-cm layer; in the soddy-podzolic-gleyish and gley and in the soddy-gley soils in the upper 12—16-cm layer, and in the peat bogs in the upper 10—11-cm layer. Most of the radionuclide inventory is, as a rule, within the horizons A0 and A1.