Effectiveness of wetlands to phytoremediate zinc, lead and chromium

This study was conducted to assess the levels of zinc, chromium and lead in the Mvudi River, located in Thohoyandou in the Limpopo Province, South Africa. Enlighten with the recent developments of plant species as remediates, plants were sampled for this study to assess their phytoremediation efficiency. The surface water and plant samples were collected before, within and after a wetland near a cement brick making factory. The samples were analyzed to determine the concentration of zinc, lead and chromium. The results showed that zinc was the most concentrated metal in plants and water reaching a concentration levels of up to 4.52 mg kg^-1 in the leaves of Bidens pilosa and 0.77 mg L^-1 within the wetland. Chromium and lead were easily absorbed by the roots of the plants as showed by the significant decrease in concentration while moving into the wetland. The highest concentrations of chromium in plants was 0.41 mg kg^-1 in Xanthium strumarium (stem). The amounts of zinc, chromium and lead in plants samples were found to be higher as compared to that of water samples and this shows that plants were absorbing large amounts of metals. Novelty Statement: Several studies that have been conducted in Mvudi River focused primarily on analyzing heavy metals in water. The aim of the present study was to assess the effectiveness of selected wetland plants as remediates of heavy metals contaminating Mvudi River in Thohoyandou, South Africa. This was done by measuring the concentration of heavy metals of selected plants before, within and after the wetland area. If high level of heavy metals in the Mvudi River are not remediated, this will affect the quality of potable water and pose serious health effect to the people. This investigation exhibited an important role the wetland plants play of accumulating heavy metals in contaminated water.