Comparative Evaluation of Aquatic Macrophytes for Heavy Metal Removal in Contaminated Wastewater Under Controlled Conditions

Heavy metal contamination of freshwater systems represents a persistent environmental challenge due to metal toxicity, non-biodegradability, and bioaccumulation potential. This study compared the phytoremediation performance of Eichhornia crassipes, Pistia stratiotes, and Chrysopogon zizanioides for the removal of chromium (Cr), copper (Cu), cadmium (Cd), and lead (Pb) from contaminated water under controlled conditions. Plants were exposed to aqueous solutions containing 5 mg L−1 of the four metals for 45 days. Metal concentrations in roots and shoots were determined by wavelength-dispersive X-ray fluorescence, translocation factor (TF), bioconcentration factor (BCF), and removal efficiency (RE) were calculated. TF values (0.02–2.90) varied across species, metals, and experimental conditions, indicating a general tendency for metal retention in roots, although translocation to shoots occurred in several cases. BCF values (0.04–87.55) were significantly influenced by species, exposure time, and treatment (p < 0.05), with P. stratiotes showing higher accumulation under specific conditions (Cu = 87.55; Pb = 44.56). In contrast, RE showed high variability (−616.21 to 72.72%) and no significant differences among experimental factors. Overall, the results demonstrate context-dependent variation in metal uptake and translocation, highlighting the potential of aquatic macrophytes as low-cost alternatives for the treatment of metal-contaminated wastewater systems.