Heavy metal pollution of water is of concern for human health and ecosystem. Under present investigation Pistia stratiotes L. (water lettuce) has been tested for removal of two important heavy metals chromium (Cr) and lead (Pb) from metal solution. This species was grown at four concentrations of Cr and Pb, i.e. 5.0, 10.0, 15.0 and 20.0 mg/L, respectively in single metal solution. This aquatic macrophyte has successfully removed up to 80% of Cr and 93% of Pb after 10 days. The bioconcentration factor (BCF) value ranged between 299 and 1026 for Cr and between 1672 and 1852 for Pb, respectively. The amount of BCF in Pistia stratiotes showed that removal of Pb was higher than removal of Cr. The accumulation of heavy metals was more obvious in the roots as compared to leaves. These findings contribute to the application of aquatic macrophytes to lead and chromium removal from moderately contaminated waters.

The present study deals with comparative evaluation of three different aquatic macrophytes, i.e. Myriophyllum spicatum, Sagittaria sagittifolia and Pistia stratiote planted at three different concentrations (1.0, 3.0 and 5.0 mg/L) of metals in laboratory experiment for Cd, Cu and Zn removal from aqueous solution. Result revealed high removal (>90%) of different metals during 15 days experiment. Highest removal was observed on 13th day of experiment, thereafter it decreased. Results revealed Pistia stratiote as the most efficient for the removal of selected heavy metal followed by Sagittaria sagittifolia and Myriophyllum spicatum. Selected plants can be used for large scale removal of Cd, Cu and Zn from waste water.