Root uptake of 137Cs and 90Sr by rye-grass on various soils in the CIS

Caesium-137 and 90Sr were measured in samples of rye-grass and soil collected during 1992 from field plots at seven experimental sites in Belarus, Russia and Ukraine contaminated by fallout from the Chernobyl accident in 1986. On five soddy podsolic mineral soils, the concentration ratio (CR) (Bq kg−1 dw rye-grass/Bq kg−1 dry soil to 10cm) for 90Sr always exceeded that for 137Cs but on one peaty soil, the CR for 137Cs exceeded that for 90Sr. On a second peaty soil, both CRs were small and probably very similar. The CRs for 137Cs on the mineral soils ranged from 0.05 to 0.39 and from 0.65 to 0.90 for 90Sr. On the peat 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 heavily contaminated with fuel particles at the time of sampling.