Water cleaning from toxic elements using phytofiltration with Elodea canadensis

摘要

Using plants to remove toxic elements from various polluted waters has successfully been shown by so called phytofiltration. Best results are found when using submerged plants, and among the submerged species tested Elodea canadensis is suitable. The aim was to investigate the removal efficiency of a number of toxic elements and essential basic cations by E. canadensis. The importance was to find out if removal of toxic elements could be performed without a significant alteration of the element concentration of the essential basic cations. In five different studies we investigated removal of Cd, Cu, Zn, Pb, Sb, As, Mg, Ca, Na, K as well as changes in alkalinity (HCO_3~-) and pH by f. canadensis. The data showed that plants removed 51% Zn, 33% Cu, 41% Cd, 32% Pb, 75% As and 8% Sb. There was no removal of Mg, Ca, Na and K, and no or only a small change in HCO_3~- and pH. Thus, it seems possible to remove toxic elements from water by submerged plants and simultaneously keep the essential elements in the water for a good water quality.