Accumulation and distribution of ²⁴¹Am in the biomass of freshwater plant Elodea canadensis

Abstract
Accumulation of transuranic element ²⁴¹Am by photoassimilating organs and its distribution in fractions of the biomass of aquatic plant Elodea canadensis have been investigated in laboratory batch experiments. Americium was taken up by apical shoots of Elodea from water. Of the activity accumulated by the shoots, up to 80% of ²⁴¹Am was detected in the leaves and 20% in the stems. Americium concentration in apical leaves was several times higher than in distal leaves. Of the ²⁴¹Am activity concentrated in the shoots, 95% was bound to cell walls, membranes and organelles and 5% of the radionuclide was dissolved in cytoplasm. Less than 1% of americium accumulated in the biomass was found in the lipid extract; up to 10% of americium was bound to proteins and carbohydrates; the major part of the radionuclide (about 90%) was registered in the cell wall fraction that mainly contained cellulose-like polysaccharides. Biomass treatment with hydrochloric acid resulted in desorption of about 70% of americium, mostly from the polysaccharides.