Advances in Phytoremediation-Based Strategies for Co-Contaminated Riparian Soils: A Review

Riparian soils co-contaminated with heavy metals and organic pollutants present a formidable environmental challenge; conventional single-target remediation strategies are frequently insufficient due to the synergistic interactions between contaminant classes. This review offers a systematic synthesis of phytoremediation as an integrative and ecologically sustainable paradigm for addressing these complex multi-pollutant scenarios. Through a critical examination of underlying mechanisms—namely phytoextraction, rhizodegradation, phytostabilization, and phytovolatilization—we evaluate the efficacy of selected hyperaccumulator and pollution-tolerant species in simultaneously mitigating inorganic (e.g., Pb, Cd, As) and organic (e.g., PAHs, pesticides) contaminants. Furthermore, the discussion highlights emerging strategic integrations, including genetic engineering for enhanced metal accumulation, the application of engineered nanomaterials to modulate pollutant bioavailability and plant stress tolerance, rhizosphere amendment with low-molecular-weight organic acids, and biochar-mediated immobilization coupled with microbial stimulation. The analysis posits that phytoremediation, particularly when augmented by these advanced synergies, constitutes a viable, multifunctional, and environmentally benign strategy for the holistic restoration of riparian ecosystems. Future inquiries should prioritize the mechanistic elucidation of combined technologies, the development of predictive performance models, and rigorous long-term field validation to guarantee operational efficacy and environmental safety.