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CHERNOBYL9. Chernobyl’s Radioactive Impact on FloraAlexey V. YablokovPlants and mushrooms accumulate the Chernobyl radionuclides at a level that dependsupon the soil, the climate, the particular biosphere, the season, spotty radioactive contamination,and the particular species and populations (subspecies, cultivars), etc. Eachradionuclide has its own accumulation characteristics (e. g., levels of accumulation forSr-90 are much higher than for Cs-137, and a thousand times less than that for Ce-144).Coefficients of accumulation and transition ratios vary so much in time and space thatit is difficult, if not impossible, to predict the actual levels of Cs-137, Sr-90, Pu-238, Pu-239, Pu-240, and Am-241 at each place and time and for each individual plant or fungus.Chernobyl irradiation has caused structural anomalies and tumorlike changes in manyplant species. Unique pathologic complexes are seen in the Chernobyl zone, such as ahigh percentage of anomalous pollen grains and spores. Chernobyl’s irradiation has ledto genetic disorders, sometimes continuing for many years, and it appears that it hasawakened genes that have been silent over a long evolutionary time.There are thousands of papers about agricultural,medicinal, and other plants and mushroomscontaminated after the Chernobyl catastrophe(Aleksakhin et al., 1992; Aleksakhin,2006; Grodzinsky et al., 1991; Ipat’ev 1994,1999; Parfenov and Yakushev, 1995; Krasnov,1998; Orlov, 2001; and many others).There is also an extensive body of literatureon genetic, morphological, and other changesin plants caused by Chernobyl radiation. Inthis chapter we present only a relatively smallnumber of the many scientific papers thataddress Chernobyl’s radioactive impact onflora.The Chernobyl fallout has ruined the pineforests near the nuclear power plant, whichwere not able to withstand the powerful radioactiveimpact, where contamination in thefirst weeks and months after the catastrophereached several thousand curies per squarekilometer. With the catastrophe’s initial atmosphericradiotoxins (see Chapter 8) and theAddress for correspondence: Alexey V. Yablokov, RussianAcademy of Sciences, Leninsky Prospect 33, Office 319, 119071Moscow, Russia. Voice: +7-495-952-80-19; fax: +7-495-952-80-19.Yablokov@ecopolicy.rupowerful irradiation caused by “hot particles,”the soil and plants surfaces became contaminatedand a cycle of absorption and release ofradioisotopes from soil to plants and back againwas put into motion (Figure 9.1).Soon after the catastrophe plants and fungiin the contaminated territories became concentratorsof radionuclides, pulling them fromthe soil via their roots and sending them toother parts of the plant. Radionuclide levels inplants depend on the transfer ratio (TR, transitioncoefficient) and the coefficient of accumulation(CA)—the relationship of specific activityof a radionuclide in a plant’s biomass tothe specific activity of the same radionuclide insoil: [TR = (Bq/kg of plant biomass)/(kBq/m 2for soil contamination); CA = (Bq/kg of plantbiomass)/(Bq/kg of soil)].9.1. Radioactive Contamination ofPlants, Mushrooms, and LichensThe level of radionuclide incorporation (accumulation)in a living organism is a simpleand reliable mark of the potential for damageto the genetic, immunological, and life-support237