Elimination of toxic heavy metals from industrial polluted water by using hydrophytes

Abstract

Heavy metals (HMs) are frequently detected in wastewaters, especially in industrial discharges. Phytoremediation is one of the promising low cost, environmental friendly and efficient technique to remove HMs from industrial wastewater. The current research was carried out to investigate the ability of constructed wetland (CW) for the removal of HMs including copper (Cu), cadmium (Cd), lead (Pb), nickel (Ni) and chromium (Cr) from local wastewater of industries by using two local common hydrophytes species Pistia stratiotes and Lemna Gibba. After 45 days cultivation, the concentration of HMs reduced to 0.25–0.90 mg/L and 0.78–1.4 mg/L from 5 mg/L for Lemna gibba and Pistia stratiotes, respectively. The HMs removal efficiency ranged from 82% to 95% for Lemna gibba and 72%–84.4% for Pistia stratiotes. The accumulation of HMs in roots are always higher than that in aerial part including stems and leaves for both plants. The accumulation of HMs in roots of Lemna gibba ranged from 4.3 to 4.7 mg/kg and, 1.85–3.9 mg/kg in aerial part. The corresponding values were 3.9–4.7 mg/kg and, 1.75–3.3 mg/kg for Pistia stratiotes. Results of health risk models including the average daily intake (ADI), hazard quotient (HQ) and cancer risk (CR) models indicated lower health risk of water after treatment than before treatment water. Result indicated the selected hydrophytes could be applied for HMs treatment from contaminated water.