Phytoremediation of heavy metals from aqueous solutions by two aquatic macrophytes, Ceratophyllum demersum and Lemna gibba L.

Wetland plants are being used successfully for the phytoremediation of trace elements in natural and constructed wetlands. Under the present investigation, two aquatic macrophytes, Ceratophyllum demersum and Lemna gibba, were tested for their effectiveness at removing two toxic metals (Pb and Cr). These plants were grown at four different concentrations in single-metal solutions of the two metals and were separately harvested after 2, 4, 6, 9 and 12 days in a laboratory experiment. These plants performed extremely well at removing the chromium and lead from their solutions and were capable of removing up to 95% of lead and 84% of chromium during the 12-day incubation period. The removal continued through the 12 days and up to the highest value on the 12th day of the experiment. The results revealed that, of the two species, L. gibba was the most efficient for the removal of selected heavy metals. The plants accumulated heavy metals without the production of any toxicity or reduction in growth.