Phytoremediation Strategies for Remediation of Uranium-Contaminated Environments: A Review

Uranium is one of the most toxic radionuclide contaminants and is progressively dispersing in the environment due to the exploration and utilization of nuclear energy. Uranium in the environment endangers both human and animal health, and thus proper management of uranium-contaminated environments has become an urgent need. For treatment of soils contaminated with uranium, traditionally employed chemical (extraction/washing, immobilization) and physical (excavation and disposal) treatment technologies are costly and have produced uncertain results and consequently, alternative pollution control techniques involving various strategies have been considered. Phytoremediation has been widely accepted as an economic, environment-friendly and efficient approach for management of soils contaminated by uranium. As uranium speciation and its bioavailability are closely related to soil properties, such as pH, organic matter, phosphates, carbonates, and iron oxides, they act as key factors influencing uranium uptake by plants. Based on the knowledge of these factors, various soil amendments such as citric acid, calcium carbonate, and phosphate to improve bioavailability of uranium have been proposed. In addition, inoculation of plants with biological amendments such as arbuscular mycorrhizal fungi has also emerged as an effective remediation strategy for uranium-contaminated soils. In aquatic environments, rhizofiltration can be used as a suitable approach for uranium remediation. With the recent developments, phytoremediation has the potential to become an integral part of the management of uranium-contaminated environments.