Accumulation and release of ⁹⁹Tc by a macrophyte of the Yenisei River (Elodea canadensis) in laboratory experiments

Abstract

The study addresses ⁹⁹Tc accumulation and release by Elodea canadensis, one of the abundant species of submerged plants in the Yenisei River ⁹⁹Tc in water samples of the “Elodea-Yenisei River water” model system and in the biomass fractions was measured using a liquid scintillatio analyzer. Experiments on accumulation of ⁹⁹Tc by Elodea showed that ⁹⁹Tc activity concentration can reach 120±6 Bq/g dry wt, with concentration factor for ⁹⁹Tc 2700±500 l/kg dry wt. In experiments on ⁹⁹Tc release, over 504 hours about 82% of the total ⁹⁹Tc activit released into the water from the plant; most of ⁹⁹Tc was released within the first 192 hours. The data obtained using sequential chemica fractionation of biomass confirmed the experimental data on ⁹⁹Tc release, which suggested that most of the biomass-bound ⁹⁹Tc was adsorbed the surface of Elodea. ⁹⁹Tc tightly bound to biomass (fractions of organics and mineral residue) constituted just 17% of the total ⁹⁹Tc activity.