ROOT UPTAKE OF CS-137 AND SR-90 BY RYE-GRASS ON VARIOUS SOILS IN THE CIS

Caesium-137 and Sr-90 were measured in samples of rye-grass and soil c ollected during 1992 from field plots at seven experimental sites in B elarus, Russia and Ukraine contaminated by fallout from the Chernobyl accident in 1986. On five soddy podsolic mineral soils, the concentrat ion ratio (CR) (Bq kg(-1) dw rye-grass/Bq kg(-1) dry soil to 10 cm) fo r always exceeded that for Cs-137 but on one peaty soil, the CR for ex ceeded that for Sr-90. On a second peaty soil, both CRs were small and probably very similar. The CRs for Cs-137 on the miner al soils range d from 0.05 to 0.39 and from 0.65 to 0.90 for Sr-90. On the pear soils , the ranges were 0.05 to 0.76 and 0.11 to 0.38, respectively. On the mineral soils, the lowest values of CR were found at a site still heav ily contaminated with fuel particles at the time of sampling. (C) 1997 Elsevier Science Ltd.