Follow up study of radiocesium contamination in a Greek forest ecosystem.

Radiocesiun distribution in the different parts of a Quercus conferta Kit ecosystem in Northern Greece was measured in 2005-2006, twenty years after the Chernobyl accident. The comparison between the results of this study and those previously measured (1993-1995) in the same ecosystem gives information about the long-term behavior of 137Cs in forest ecosystems. The major part of the 137Cs inventory is still in the upper layers of the soil. The radiocesium distribution in soil is fixed and has been in equilibrium at least since 1993, when the first measurements were performed. The major contamination mechanism of leaves and wood is root uptake.