Ecotoxicity, Oxidative Stress and Phytoremediation of Nickel on Aquatic Plants

Abstract

The search for environmental friendly practices and new technologies in order to reduce ecological impact associated with nickel disposal and pollution remains open. In this sense, phytoremediation outstands as a high efficiency eco-friendly green technology for removing pollution from contaminated soil, water and air. It is a form of bioremediation and an economical and sustainable alternative to traditional chemical and physical pollution remediation methods. High metal bioaccumulation efficiency and tolerance are requisite for plants employed in phytoremediation techniques; thus, investigating new aquatic plants with such characteristics is a priority. The antioxidant defense system plays a significant role in providing resistance to plants by protecting labile macromolecules against the attack of free radical. This ability made possible the use of aquatic plant in technological applications for the restoration of contaminated sediments, solid wastes as well as organic contaminants. In accordance, results have demonstrated that L. gibba and C. demersum would have the capacity of tolerate and therefore, resist to nickel stress. APX would be a more efficient enzyme in detoxification of hydrogen peroxide as its activity was stimulated at higher exposure concentrations. This reinforces the proposal of selecting APX as a good biomarker for the evaluation of the welfare of the plant and growth performance. It is important to have in mind that plant stress tolerance may be improved by the enhancement of levels of antioxidant enzymes, in particular related to the application of aquatic plants in phytoremediation of nickel from wastewaters and industrial effluents.