Removal of Lead from Synthetic Wastewater using Aquatic Plants

Abstract

Abilities of aquatic plant species, Echinodosus cordifolius (L.) Griseb., Bacopa caroliniana (Walt.) Rob., and Hydrocotyle umbellata L., for phytoremediation of lead (Pb) from synthetic wastewater were conducted in hydroponic system at 20-80 mg/L of Pb (II) and 7-28 days of exposure periods. Additional experimental set up for aquatic plant species under 60 and 80 mg/L of Pb (II) were added with 5 mM EDTA in order to enhance Pb accumulation in the plants. Results revealed that the capacity of Pb (II) accumulation at 80 mg/L of Pb (II), 28 days in roots of all aquatic plants was higher than that of shoots. E. cordifolius (L.) Griseb. had the highest capacity of Pb (II) accumulation about 12,566 (roots) and 8,686 (shoots) mg/kg dry wt, respectively giving 95% of Pb (II) removal, followed by H. umbellata L. and B. caroliniana (Walt.) Rob., respectively. Regarding EDTA addition, lead accumulation (80 mg/L of Pb (II), 7 days) was increased in the roots of H. umbellata L. about 19,883 mg/kg dry wt and it was increased in the shoots of E. cordifolius (L.) Griseb. about 14,516 mg/kg dry wt (80 mg/L of Pb (II), 21 days), respectively. The highest relative growth (13.85) and percentage of biomass productivity (98%) were in H. umbellata L. (60 mg/L of Pb (II), 7 days), whereas the highest bioconcentration factor (9,341.68) was in E. cordifolius (L.) Griseb.(80 mg/L of Pb (II), 21 days). According to the results, E. cordifolius (L.) Griseb. was recommended to remove the lead from synthetic wastewater with EDTA addition. Further studies in contaminated wastewater under various characteristics and flows should be investigated.