Ethnomedicinal plants as green tools for heavy metal phytoremediation from soil and water: a review.

Source: PubMed, NCBI / U.S. National Library of Medicine

Heavy metal contamination by zinc (Zn), lead (Pb), iron (Fe), cadmium (Cd), chromium (Cr), arsenic (As), and mercury (Hg) poses serious environmental and health risks due to persistence, bioaccumulation, and toxicity even at low concentrations. Phytoremediation has emerged as an eco-friendly and cost-effective alternative, reducing remediation costs by 30-70% compared to conventional methods. This study evaluates the phytoremediation potential of ethnomedicinal plants and their mechanisms for heavy metal removal.A systematic literature review was conducted using PubMed and Google Scholar for studies published between 2005 and 2025. Of 223 identified articles, 28 duplicates were removed, leaving 195 for screening. After excluding 40 irrelevant and 20 low-quality studies, 135 articles were included in the final analysis.Key mechanisms identified include phytoextraction, phytostabilization, and rhizofiltration. Brassica juncea accumulates Pb and Cd up to 800-1,500 mg/kg, while Helianthus annuus removes 60-85% of Pb and Zn within 6-8 weeks. Sedum alfredii accumulates over 2,000 mg/kg Cd, and Pteris vittata accumulates up to 5,000 mg/kg As. Overall, phytoremediation reduces heavy metal concentrations by 40-90% within 2-12 months.Phytoremediation is 5-10 times more cost-effective than conventional methods and enhances soil fertility, biodiversity, and carbon sequestration, making it a sustainable solution for heavy metal pollution.