ABSTRACT
102Phytoremediation of selenium (Se)-containing Hoagland solution and seleniferous soil leachate was evaluated using with two aquatic plants, Lemna minor and Egeria densa. The soil leachate was prepared by washing the soil in a liquid to solid (L:S) ratio of 10:1 (v/w) with H2O, KMnO4 and K2S2O8 at 250 rpm for 6 h. The composition of each seleniferous soil leachate was determined. Based on this, an artificial seleniferous soil leachate was modelled for understanding the phytoremediation process. L. minor showed the highest Se removal efficiency (97%) in Hoagland solution, followed by 85% Se removal in the artificial soil leachate. L. minor showed removal efficiencies of 80% and 99% for Se and Mn, respectively, due to simultaneous removal of both the metal(loid)s. Addition of K2S2O8, however, decreased the uptake of Se by the plants investigated by 40% and the medium pH from 7 to 3. Se removal efficiency of aquatic plants decreased by 30% when sulfate was included. L. minor showed a Se removal efficiency of 76% with Se uptake of 29 μg g−1 dry weight from seleniferous soil leachate which contained 74 μg L−1 Se. This study demonstrated that aquatic plants such as Lemna minor and Egeria densa were able to remove Se from seleniferous soil leachate and phytoremediation efficiency depends on the composition of the extractant used for soil washing.
