Removal of Heavy Metals from Aquatic Environments Using Water Hyacinth and Water Lettuce

The quality of the aquatic environment was strongly influenced by the development of urbanization, industrialization and population growth, and therefore water pollution, mainly due to the presence of heavy metal, becoming a widespread concern. The objective of this work was to evaluate the possibility to remove heavy metals Cd, Zn, Cr and Ni from wastewater using two aquatic plants, water hyacinth (Eichornia crassipes) and water lettuce (Pistia stratiottes). These plants possess excellent abilities to metabolize and bioaccumulate heavy metals from various polluted aquatic environments. For a period of 30 days, the content of heavy metals from wastewater and aquatic plants samples was monitored weakly and the efficacy of these plants to remove heavy metals was quantified. Heavy metals were determined by atomic absorption spectrophotometry with graphite furnace (GFAAS). The obtained results have shown the efficacy of Eichornia crassipes and Pistia stratiottes to remove metals from the studied wastewater. The bioaccumulation rate of heavy metals in plants was effective until day 24 of the period of 30 days of the experiment, as the plants become inefficient beyond this period. The uptake of heavy metals in the studied aquatic plants depends on the concentration of each heavy metal present in the used wastewater and the exposure time.