Phytofiltration of As³⁺, As⁵⁺, and Hg by the aquatic macrophyte <i>Potamogeton pusillus</i> L, and its potential use in the treatment of wastewater

<p>The aim of this paper was to investigate the capacity of the aquatic macrophyte <i>Potamogeton pusillus</i> 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 <i>P. pusillus</i>, 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 <i>P. pusillus</i> 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 <i>P. pusillus</i>.</p