Caesium-137 behaviour in small agricultural catchments on the area of the Chernobyl contamination

The vertical distribution of Cs-137 from the Chernobyl accident in soils of the basin of the Gusinaya Lapka dry river, situated in the Eastern region, 550 km from the reactor, has been investigated. In this area the Cs-137 co ntamination levels range between 250 and 502 kBq m(-2). In the accumulation zones, at the bottom of the valley, the sediment deposits over the last te n years represent a layer of not more than 10 cm. On arable lands, the eros ion processes are limited and no perceptible redistribution of Cs-137 could be observed, except at the transition between ploughed lands on the inter- rivers and meadows on the balka slopes. This study demonstrates the potenti al use of the Cs-137 from the Chernobyl accident for the quantification of the soil erosion process.