Potential of Pistia stratiotes, Eichhornia crassipes and algae for removing Cobalt (Co) and Nickel (Ni) at various concentrations

Phytoremediation is a new emerging discipline to de-contaminate polluted water. Remediation of pollutants by plants is environmental friendly and cost effective technique. Present study focuses on ability of Pistia stratiotes, Eichhornia crassipes and algae for removing nickel (Ni) and cobalt (Co) from aquatic system. Efficiencies of these macrophytes were checked against Ni and Co (2mg/l and 4mg/l concentration for each metal) on lab scale under natural conditions for a period of fifteen days. Samples were collected and analyzed at 0, 5, 10 and 15 days. One-way ANOVA was applied to compare significance level of these plants for removal of these metals. P. stratiotes, E. crassipes and algae removed 90.5%, 90.6% and 87.5% at 2mg/l Ni concentration, while 94.55%, 98.1% and 80.25% respectively at 4mg/l Ni from water. Similarly, P. stratiotes, E. crassipes and algae removed 95.5%, 98% and 80% Co metal at 2mg/l concentration, but 91.5%, 99% and 79.75% respectively at 4mg/l concentration of Co. Results indicate that E. crassipes is more efficient for removal of both the metals at p < 0.005. There was no change in color and biomass of these macrophytes but biomass of algae increased in both treatments (2 and 4mg/l) for both metals during 15 days’ period