Cation exchange resin saturated with H+ and Ca2+ was used to extract C
s-137 from peat soil at two sites in Britain affected by Cs-137 deposi
tion following the Chernobyl accident. The technique identified three
classes of Cs-137, similar to those observed for K+ in soils: 'Fast',
'Intermediate' and 'Slow'. These classes are probably related to the s
electivity for Cs-137 Of the cation exchange sites on the organic matt
er and the clay minerals, and to the structure of the soil. With one e
xception, most Cs-137 was in the 'Slow' form and was only very slowly
released to the resins, if at all. However, there was enough Cs-137 in
the 'Fast' and 'Intermediate' forms to contaminate pasture and thus g
razing animals for some years. Based on the resin technique, it is est
imated that contamination will persist for several decades in uplands
contaminated at these activity concentrations.