Uranium and radium accumulation by wild plants and their phytoremediation potential

The paper presents the results of studying the accumulation of uranium and radium-226 in canary grass ( Phalaris arundinacea L.) and sedge ( Carex acuta L.) in order to identify their role in the biogeochemical cycles of radionuclides, as well as their phytoremediation potential for use in remediation of radioactive contaminated territories. The content of radionuclides in soils has increased as a result of the activity of radium production enterprise in 1930-1950. Uranium content in the studied soil samples varied within 0.83-1.65 μg / g dry weight. Activity concentrations of radium-226 were in the range 1.82-37.6 Bq / g dry weight. The investigated plants were dug up by the roots. The root part was washed from the soil and separated from the aboveground biomass. In both parts of the plants, concentrations of uranium and radium-226 were determined. Based on the obtained data, bioconcentration factors (BCF) of radionuclides in both parts of the plants relative to the soil were calculated. Transfer factor TF (root / aboveground part) was also calculated as the ratio of the radionuclide concentrations in the aboveground part of plants and their roots. It was revealed that the accumulation of uranium and radium-226 in the aboveground part of the plants is low, which does not allow us to classify these species as concentrators of the studied radionuclides. BCFs (aboveground parts / soil) for uranium were ranged in 0.02-0.04. In the case of radium-226, BCFs varied from 0.007 to 0.12. The main part of uranium and radium-226 was accumulated in the root system of plants, which served as a barrier for the transfer of radionuclides to their aboveground parts. TFs (aboveground part / root) was 0.17-0.37 for uranium and 0.08-0.29 for radium. The obtained results indicate that canary grass and sedge contribute to the stabilization of uranium and radium in the studied soil and have the potential to be used as phyto-stabilizators for these contaminants.