Dual-Plant Phytoremediation Strategy for Lead Decontamination Using Helianthus Annuus and Ocimum Sanctum

Abstract

Lead (Pb) contamination in soil poses a serious threat to the environmental and human health due to its non-biodegradable and highly toxic nature. Phytoremediation, an eco-friendly and cost-effective technique, utilizes plants to extract, immobilize, or stabilize the heavy metals from contaminated environments. In this work, the phytoremediation ability of Ocimum sanctum (tulsi) and Helianthus annuus (sunflower) in lead-spiked soils is assessed and contrasted.A controlled pot experiment was conducted over the course of 90 days under consistent climatic conditions, utilising three different lead concentrations (100, 200, and 400 mg/kg) along with a control. Atomic Absorption Spectrophotometry was used to quantify the Pb concentration in root and shoot tissues as well as plant biomass according to standard procedures.The performance of phytoremediation was analysed employing quantitative indicators like the Bioaccumulation Factor, Translocation Factor, and Remediation Efficiency. Because of its increased translocation ability (Translocation Factor (TF) > 1) and shoot Pb accumulation, the study's findings suggested that Helianthus annuus (H. annuus) offers a significant potential for phytoextraction. However, Ocimum sanctum (O. sanctum) retained higher Pb in its roots (TF < 1), making it suitable for phytostabilization. Compared to H. annuus, O. sanctum had a more pronounced decline in biomass as Pb stress increased, suggesting a less effective tolerance.The results suggest that a dual-plant strategy using Helianthus annuus for active Pb removal and O. sanctum for root-zone root-zone stabilization. This comparative analysis supports species specific phytoremediation technique and provides the promising framework for environmentally sustainable lead decontamination.