Accumulation of Am-241 by the Submerged Macrophyte Elodea canadensis and Assessment of Radionuclide Toxicity with Direct and Indirect Effects

A submerged macrophyte of the Yenisei River, Elodea canadensis, was used to study the microdistribution of the artificial radionuclide 241Am among different components of the plant. The total amount of 241Am added to the experimental system was 1850±31 Bq/L. The total amount of 241Am accumulated by the plants was 182 Bq per sample, or 758±385 Bq/kg dry mass. It has been found that the major portion of 241Am accumulated by E. canadensis, up to 85%, was bound to solid components of the cells. It is observed that the microdistribution of 241Am within different components of the submerged plant E. canadensis was not uniform. 241Am distribution vary depending on the age of the leaf blades, the state of the cells and morphological features of the plant stem. Toxicity and genotoxicity of the E. canadensis containing 241Am have been evaluated for the first time. It is shown that the suspensions and extracts of plants which do not contain 241Аm, inherently decrease the survival of bacterial cells of specific strains as compared to the control samples. Cell death of Е. Coli in the aqueous plants accumulating 241Аm was observed to be even higher, which is consistent with the toxicity of the control samples of aqueous solutions of 241Аm salts. Non-radioactive suspensions of the control samples of the plants also slightly influenced the survival of the S. typhimurium TA98 cells, whereas their survival abruptly decreased in the presence of 241Аm.