Performance and efficiency services for the removal of hexavalent chromium from water by common macrophytes

Abstract

Water contamination by hexavalent chromium(Cr) is an emerging issue. The removal of Cr(VI) using phytoremediation via different macrophytes was investigated in this study. To reduce Cr(VI) to the permissible level in irrigation water, the ability of four common macrophytes, viz. <i>Pistia stratiotes</i> (PS)<i>, Salvinia minima</i> (SM)<i>, Ipomoea aquatica</i> (IA) and <i>Eichhornia crassipes</i> (EC), to remove from 0.5 to 2.0 mg Cr(VI)/L was analyzed. The overall growth of PS was enhanced by 11 to 24%, SM by 36 to 53%, EC by 65 to 101% and IA by 4 to 13% by reducing Cr from 48 to 87% within 29 days of the experiment. In successive experiments, chromium uptake by SM surpassed ∼11.86-, ∼17.17- and ∼94-fold that of PS, EC and IA, respectively, after 15 days of growth in 0.35 to 1.75 mg Cr(VI)/L. The bioconcentration factor of SM surpassed that of PS, IA and EC by 0.64 to 1.73, 1.09 to 4.07 and 0.71 to 1.85 times, while PS exceeded IA and EC by1.71 to 2.35 and 1.07 to 1.11 times, respectively. SM was thus shown to offer efficient removal of Cr(VI), from a level ≅2.0 mg/L, while a suitable combination of SM and PS was efficient at ≤1.0 mg/L. <b>Novelty</b> It unravels the appropriate macrophytes in terms of biomass production and Cr- uptake pattern under natural condition for phytoremediation of aqueous Cr(VI) and in turn offer services to clean the environment.