Assessing the Phytoremediation Potential of Ornamental Plants in Heavy Metal-Contaminated Soils

Rapid industrialization and human activities have led to the accumulation of heavy metals in soil, posing serious threats to ecosystems and human health. Phytoremediation, which uses plants to remove or neutralize pollutants, is an effective, low-cost, and eco-friendly way to clean soil. While grasses have been widely studied for this purpose, the potential of ornamental plants remains underexplored. This study addresses the research question: Can selected ornamental plant species efficiently remediate red soil contaminated with Pb, Cd, and Cr, while offering aesthetic value in urban areas? To address the question, a controlled pot experiment was conducted over 28 days using red soil artificially contaminated with known concentrations of Pb, Cd, and Cr. Plants were assessed for growth performance, metal accumulation in root and shoot tissues, and the reduction in soil heavy metal content post-harvest. Results revealed that Tagetes and Iberis exhibited the highest efficiency in Pb uptake, reducing its concentration by up to 60%, along with moderate uptake of Cd and Cr, varying by species. The novelty of this work lies in evaluating the dual role of ornamental plants as both beautification agents and phytoremediators, particularly focusing on three species: Tagetes erecta (Marigold), Crossandra infundibuliformis (Crossandra), and Iberis (Candytuft). This study is the first to compare Tagetes erecta, Crossandra infundibuliformis, and Iberis (Candytuft) for removing multiple heavy metals from red soils. Tagetes showed good tolerance to cadmium and chromium. Iberis removed lead effectively. These plants can help clean the environment while adding beauty to urban and industrial areas.