Plant Responses to Radionuclides and Heavy Metals in Uranium Mining Sites: Mechanisms and Phytoremediation

Uranium mining and processing have resulted in widespread environmental contamination by radionuclides and associated heavy metals, creating long-term ecological challenges because of their persistence, mobility, and bioavailability. The aim of this review is to evaluate knowledge on the uptake, accumulation, and biological effects of radionuclides and associated heavy metals in plants, identify the environmental factors governing their bioavailability, and assess recent advances in phytoremediation strategies for the sustainable restoration of uranium-contaminated ecosystems. A critical analysis of the published literature was conducted to evaluate contaminant sources, environmental factors regulating bioavailability, root and foliar uptake pathways, internal transport mechanisms, morphological, physiological, and biochemical biomarkers of plant stress, and phytoremediation approaches. The reviewed evidence demonstrates that plant responses occur at multiple levels of biological organization, including alterations in growth and anatomy, disturbances in photosynthesis and nutrient metabolism, and activation of antioxidant defense systems. Integrating these biomarkers provides a more comprehensive assessment of contaminant-induced stress than individual indicators alone. The literature further indicates that phytostabilization and phytoextraction, particularly when combined with soil amendments and beneficial rhizosphere microorganisms, represent promising approaches for reducing contaminant mobility and supporting ecosystem restoration. However, important knowledge gaps remain regarding native plant species and long-term field validation in uranium mining regions. This review provides a scientific basis for improving ecological monitoring, environmental risk assessment, and sustainable rehabilitation of uranium-contaminated ecosystems.