Possibilities of transfer factor control and biotechnology for contaminated soil remediation

Two groups of biological factors that determine intensity flow and radionuclide (RN) retention in 'soil-plant' system have been investigated: 1) the size of biologically mobile fraction and 2) the selection ability and general plant capacity. The combination 'microorganisms + high plant' increases radionuclide accumulation of dry biomass nearly 3.5-4 times. Seeds and seedlings treatment and sowing of the same type of phytosiderophores and chelats increase the RN accumulation from 2.8 to 4 times. Evaluation of 90Sr and 137Cs adsorption kinetics and degree of interconnection between the accumulation level and 12 main physiological parameters (calculation coefficient Brave-Pirsona) have demonstrated higher significant correlation with CEC (Donnane Free Space Cation Exchange Capacity) value. The correlation index 'accumulation level/ CEC size' is R=0.945 for 137Cs and R=0.963 for 90Sr in 30 species. Another biochemical characteristics that have high level correlation (R=0.67 and R=0.72 respectively) are cellulose and pectin contents. It is known that cellulose and pectin are main components of cell walls and contain functional groups binding cations. These data suggest that the ion exchange capacity adsorption is the leading factor that determines selectivity adsorption of biogenous as well as nonbiogenous radionuclides. In order to increase the radionuclide accumulation, treatment of plants by the same bioactive factors elevating cellulose and pectin contents have been also conducted. The results received will be taken into account in elaboration of phytotechnology of soil remediation. (author)