Phytoremediation of Cd, Ni, Pb and Zn by Salvinia minima

Abstract

Most metals disperse easily in environments and can be bioconcentrated in tissues of many organisms causing risks to the health and stability of aquatic ecosystems even at low concentrations. The use of plants to phytoremediation has been evaluated to mitigate the environmental contamination by metals since they have large capacity to adsorb or accumulate these elements. In this study we evaluate Salvinia minima growth and its ability to accumulate metals. The plants were cultivated for about 60 days in different concentrations of Cd, Ni, Pb and Zn (tested alone) in controlled environmental conditions and availability of nutrients. The results indicated that S. minima was able to grow in low concentrations of selected metals (0.03 mg L⁻¹ Cd, 0.40 mg L⁻¹ Ni, 1.00 mg L⁻¹ Pb and 1.00 mg L⁻¹ Zn) and still able to adsorb or accumulate metals in their tissues when cultivated in higher concentrations of selected metals without necessarily grow. The maximum values of removal metal rates (mg m² day⁻¹) for each metal (Cd = 0.0045, Ni = 0.0595, Pb = 0.1423 e Zn = 0.4046) are listed. We concluded that S. minima may be used as an additional tool for metals removal from effluent.

Keywords::

• aquatic macrophytes
• effluent treatment
• metals
• bioaccumulation
• continuous flow

Funding

The authors thanks the Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq (processes 556092/2010-4; 144436/2010-8), Fundação de Amparo à Pesquisa do Estado de São Paulo - FAPESP (process 2010/15728-1).