Capacity of <i>Schoenoplectus californicus</i> to Remove and Tolerate Copper, Lead, and Zinc in Constructed Wetland Systems Using Simulated Wastewater

Abstract

The development of industry has caused metal pollution of aquatic ecosystems and water deterioration worldwide. Therefore, environmentally friendly strategies for industrial wastewater treatment are needed. In this study, constructed wetlands (CWs) were planted with Schoenoplectus californicus in a culture medium with different concentrations of Cu, Pb, and Zn. The aims of this work were to evaluate the ability of S. californicus to accumulate Cu, Pb, and Zn and its physiological response to metal exposure, and assess the wastewater treatment performance of the CW systems. The accumulation of Cu, Pb, and Zn in the shoot and root of the emergent aquatic plant depended on the metal concentration during the 28&nbsp;days of exposure, except for Pb in shoots. The bioconcentration factors of Cu (46.7±10.8) and Zn (896±317) were highest in the treatment with moderate levels of metals (T-2), whereas for Pb (57.4±15.9), the maximum bioconcentration factor was recorded in the treatment with the highest metal levels (T-3). Metal translocation from root to shoot reached values greater than 1 for Cu, but were lower for Pb and Zn because accumulation occurred predominantly in the root. In general, the removal efficiency of the CW systems was higher than 90% for Pb and Zn, and higher than 80% for Cu. Furthermore, Cu, Pb, and Zn bioaccumulation in S. californicus did not reflect toxicological damage to physiological parameters, such as the formation of products of lipid membrane peroxidation. The results showed that the exposure to relatively high metal concentrations in the CWs did not affect the survival of the species. Considering the capacity of S. californicus to tolerate and accumulate Pb, Zn, and Cu, this species can be used as a phytoextractor in wastewater treatment in CW systems.