Invasive Plants as Accumulators of Heavy Metals and Potentially Toxic Elements: A Review with Implications for Remediation

Invasive plant species frequently dominate contaminated ecosystems and are increasingly reported as accumulators of heavy metals and potentially toxic elements (PTEs). While this phenomenon is widely documented, its functional implications for contaminant dynamics and remediation-oriented management remain insufficiently synthesized. This review provides a comprehensive assessment of heavy metal and PTE accumulation in invasive plants across terrestrial and aquatic environments, with emphasis on tissue-specific partitioning, environmental context, and species-level variability. Based on field surveys, controlled experiments, and biomonitoring studies, we synthesize evidence for the accumulation of key elements (As, Cd, Cr, Cu, Ni, Pb, and Zn) in the roots and above-ground tissues of terrestrial and aquatic invasive plants. The available literature reveals consistent patterns of root-dominated sequestration in many terrestrial invaders, contrasted with enhanced shoot accumulation in fast-growing aquatic species. These patterns underpin divergent functional roles, ranging from contaminant stabilization in soils and sediments to conditional phytoextraction under managed harvesting. Rather than promoting invasive plants as remediation tools, this review frames them as unavoidable functional components of contaminated landscapes. We critically evaluate their advantages, limitations, and ecological risks, identify key research gaps, and propose a context-aware framework for interpreting invasive plant-PTE interactions in environmental management.