The potentials of Eichhornia crassipes for Pb, Cu, and Fe removal from polluted waters

Toxic metals are a major group of water pollutants that find their way into water bodies through municipal, industrial, and agricultural waste discharges. Phytoremediation of these metals has become popular because of the low-cost and environmental friendliness of the technique. Here, we evaluated the potential of Eichhornia crassipes (water hyacinth, WH) to remove lead (Pb), copper (Cu), and iron (Fe) from polluted waters. Five experimental prototypes (A–E) were developed for the phytoremediation. Prototypes A, B, C, and D contained 2 L of the underlay water spiked with 1, 2, 5, and 10 mL of Pb, Cu, and Fe stock solutions, respectively, whereas prototype E was the control (i.e., deionized water). About 200 g of live WH of the same rootstock was relocated into each prototype and exposed to the same environmental conditions. The concentrations of the metals were measured every three days for a 12-day remedial period. Also, the metal concentrations in the plant tissues (leaf, stem, and root) were monitored. We observed that in prototypes A and B, the WH achieved significant Cu, Pb, and Fe removal after 12 days. The removal efficiency (RE) of 45.81%, 19.29%, and 72.03% were achieved for Pb, Cu, and Fe, respectively in prototype A, whereas it was 25.63%, 10.69%, and 42.77% in prototype B. Generally, the order of removal followed the order Fe > Pb > Cu. Likewise, the metal contents found accumulated in the plant tissues followed the same order. The leaves of WH in prototypes C and D showed rapid wilting and final death by the 12th day. Consequently, phytoaccumulation was established because the metal concentrations were in the order: root > stem > leaves.