A critical review of mechanistic insights and technological advancement for the amelioration of Pb and Cd through phytoremediation

Heavy metal contamination is a major environmental concern due to its persistence, bioaccumulation, and long-term impacts on ecosystems and human health. Among toxic metals, cadmium (Cd) and lead (Pb) are particularly harmful because of their high toxicity and carcinogenic potential, posing serious risks to plants, animals, and humans even at low concentrations. These metals often enter soil and water through industrial activities, mining, agricultural inputs, and improper waste disposal. Conventional remediation methods, such as chemical treatment, soil excavation, and stabilization, have been used to manage contaminated sites; however, they are often costly, labour- intensive, and may cause secondary environmental pollution, creating a need for more sustainable alternatives. Phytoremediation has emerged as an eco-friendly and cost-effective approach that utilizes the natural ability of plants to absorb, accumulate, detoxify, or stabilize contaminants from soil, water, and air using solar energy. The objectives of this review are to examine the mechanisms of phytoremediation and evaluate recent advance technologies that enhance its efficiency, with a focus on plant growth-promoting microorganisms, biochar, nanomaterials, CRISPR/Cas9-based genetic engineering, isotope monitoring, and AI/ML tools. The novelty of this review lies in its integrated assessment of these emerging technologies as complementary strategies for advancing sustainable heavy metal remediation. Overall, these developments highlight the growing potential of phytoremediation as a sustainable strategy for environmental cleanup. Nevertheless, challenges related to large-scale application, plant tolerance to heavy metals, and long-term ecological sustainability remain, requiring further research to enhance its practical implementation in environmental management.