A comparative study of phytoremediation potential of water lettuce (Pistia stratiotes L.) and water hyacinth (Eichhornia crassipes [Mart.] Solms) for mitigating contaminants in the Nag River, Maharashtra, India

This study examines the phytoremediation potential of two floating macrophytes, water hyacinth ( Eichhornia crassipes ) and water lettuce ( Pistia stratiotes ), for treating contaminated water from the Nag River in Maharashtra. Experiments were conducted under controlled laboratory conditions (room temperature, static setup) over a 15-day period. As a nature-based treatment, phytoremediation offers a cost-effective, sustainable, and accessible approach to improving water quality. Both plants demonstrated statistically significant reductions (p < 0.05, p < 0.01, p < 0.001) in physicochemical parameters such as pH, total dissolved solids, total hardness, biochemical oxygen demand, and chemical oxygen demand. Notable decreases were also observed for heavy metals, including Cu, Fe, Ni, Zn, Pb, Hg, and Mn. The highest removal efficiencies were observed at 50% and 75% wastewater dilutions, with improvements noted from day 3 to day 15. Maximum removal rates were seen for Fe (79-83%), Zn (74-76%), Cu (70-73%), and Pb (62-74%). Bioconcentration and translocation factors below 1 indicated limited metal transfer from roots to shoots. Both species accumulated significant metal loads with minimal visible stress symptoms, suggesting inherent tolerance to mixed contaminants. Statistical analysis confirmed the substantial impact of both plants in reducing contaminants. Overall, the results highlight the strong potential of E. crassipes and P. stratiotes as effective, eco-friendly options for remediating polluted river water. This study provides a comparative evaluation of the phytoremediation efficiency of two invasive floating macrophytes, Eichhornia crassipes and Pistia stratiotes , using real polluted water collected from the Nag River, which forms the ecological and cultural lifeline of Nagpur city, in Maharashtra, India. Unlike many previous investigations conducted using synthetic wastewater or single-source industrial effluents, this research evaluates phytoremediation performance under complex multi-pollutant river conditions. The study further integrates pollutant removal efficiency, plant growth attributes, bioaccumulation factor (BAF), and translocation factor (TF) to better understand heavy metal uptake and distribution between plant tissues. These findings provide valuable insights for the practical application of floating macrophytes in sustainable urban river remediation. • Water hyacinth and water lettuce effectively treated the Nag River wastewater. • Significant reductions observed in pH, TDS, hardness, BOD, and COD levels. • High removal rates achieved for Fe, Zn, Cu, and Pb at optimal dilutions. • Metals accumulated mainly in roots with limited shoot translocation. • Both species showed strong tolerance and sustained phytoremediation activity.