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240TABLE 9.4. Levels of Radionuclide Accumulations (Bq/kg, Dry Weight) by Some Aquatic Plants, Ukraine,1986–1993 (Bar’yakhtar, 1995)Ru-103, Ru-106, Nb-95,Species Ce-144 Rh-103 Rh-106 Cs-137 Cs-134 Zr-95 Sr-90Shining pondweed (Potamogetonnatans)Common reed grass (Phragmitescommunis), above-water partsCommon reed grass (Phragmitescommunis), underwater partsNarrow-leaved cat’s-tail (Typhaangustifolia)44,400 4,800 33,300 12,600 8,100 63,000 92526,000 3,700 8,900 12,900 4,800 3,700 599,900 6,700 129,500 66,600 21,800 13,700 2,40020,350 7,000 24,800 3,700 1,370 1,330 270et al., 2000). The most active transfer ofradionuclides from soil to plants occurs on peatbogsoil. The transfer coefficient for Cs-137from scrub forests is up to three times higherfor half-submerged soil as compared with driersoil and up to twice that for mixed vegetationas compared with pinewoods (Borysevich andPoplyko, 2002).12. The level of incorporated radionuclidestends to correlate with the density of radioactivecontamination in the soil (Figure 9.4).13. There are strong correlations betweenspecific Cs-137 activity in a phytomass of Convallariamajalis and both the density of groundcontamination (r = 0.89) and the specific activityof Cs-137 in the soil (r = 0.84; Elyashevichand Rubanova, 1993).Figure 9.2. Concentration of C-14 in tree ringsof pine (Pinis silvestris; percent difference from thelevel in the year 1950) from the 10-km Chernobylzone (Grodzinsky et al., 1995c).14. The Cs-137 CA of 120 plant speciesincreases in the following order of ecotopes:boggy forest (425) > oakwood (241) > depressionsbetween hill-forest of flood plain (188) >pinewood (94) > undrained lowland swamp(78) > hill forest of flood plains (68) > uplandmeadows (21) > drained peat-bog soil (11)> long-term fallow soil (0.04; Elyashevich andRubanova, 1993).15. Transfer ratios from soil to plants are differentfor each species and also vary by seasonand habitat (Table 9.5).16. The maximum transfer ratio (from soilto plant) of Sr-90 was measured in wild strawberries(TR 14–15), and the minimum wasin bilberry (TR 0.6–0.9) in Belarus. The Cs-137 transfer ratio in bilberry (Vaccinium myrtillus)is threefold higher than that for wild strawberry(Fragaria vesca; Ipat’ev, 1994; Bulavik,1998).17. Plants growing on hydromorphic landscapesaccumulate 10-fold more Cs-137 thanthose in automorphic soil. There is up to a50-fold difference in the Cs-137 TR betweenan automorphic and a hydromorphic environment:intensity of accumulation of Cs-137 inberries is much lower on richer and dry soils ascompared with poor and wet soils (Tsvetnovaet al., 1990; Wirth et al., 1996; Korotkova, 2000;and others).18. There are heavy accumulations of Cs-137 in a plant’s above-ground biomass in theUkrainian wet pine subor for the cowberryfamily species (Vacciniaceae): TR is about 74