Phytofiltration of As 3+ , As 5+ , and Hg by the aquatic macrophyte Potamogeton pusillus L, and its potential use in the treatment of wastewater.

The aim of this paper was to investigate the capacity of the aquatic macrophyte Potamogeton pusillus to remove As3+ , As5+ , and Hg from aqueous solutions. The plants were exposed to 0 mg.L-1 , 0.1 mg.L-1 , 0.5 mg.L-1 , 1 mg.L-1 , or 2 mg.L-1 of As3+ , As5+ , and Hg for 20 days. The results obtained for the individual removal of As3+ , As5+ , and Hg from water solutions, together with their accumulation in P. pusillus, indicate that this plant can be effectively used for the removal of Hg and of moderate concentrations of As3+ or As5+ (0.1 mg.L-1 ) from aquatic systems. Roots and leaves accumulated the highest amount of As when the plant was exposed to As5+ , but when it was exposed to As3+ , the root accumulated the highest amount of As, and the leaves, the highest amount of Hg. When compared to other aquatic plants species, the results showed that P. pusillus demonstrated a higher Hg accumulation (2465 ± 293 µg.g-1 ) when the transfer coefficient was 40,580 ± 3762 L.kg -1 , showing the great potential of this macrophyte for phytoremediation of water contaminated with Hg. To the extent of our knowledge, this is the first report on bioaccumulation of As3+ , As5+ , and Hg by P. pusillus.