Espécies de plantas nativas brasileiras com potencial de fitorremediação de metais.

Abstract

Phytoremediation (phyto = plant; remedium = cure, restoration) is the process in which plants are used for environmental decontamination, through removal, reduction, degradation and containment of the contaminant. In this process, different plants can be used, including aquatic plants and algae. Phytoremediation strategies have the potential to treat a broad spectrum of contaminants. Brazil has great potential to use phytoremediation in the treatment of contaminated areas due to its high biodiversity and climate, which are favorable to biological processes to remove contaminants. The technique is frequently used in the remediation of heavy metals, radionuclides, as well as recalcitrant organic pollutants. For a satisfactory performance in the remediation of metals, it is desirable that the plants have tolerance to the contaminant, good capacity of absorption or adsorption of the metal, high growth rate, deep root system, easy harvest. The knowledge of potentially phytoremediating plant species is an initial and fundamental step for decontamination studies and projects. So, considering the great plant diversity of Brazil, this review aimed to survey species of Brazilian flora potentially phytoremediators of heavy metals. For this, the capacity and tolerance, as well as the predominant phytoremediation process in the decontamination of heavy metals by different species and botanical families native to Brazil, were investigated in the literature. We found 108 species of native plants used in metal phytoremediation studies. The identified species belong to 42 distinct botanical families. With 19 species, the Fabaceae family is the most represented in the studies, showing potential to phytoremediate 8 heavy metals. Asteraceae also stood out with 9 species remediating 4 types of metals, and Poaceae with 5 species studied remediating 6 metals. Regarding metals, it is clear that most phytoremediation studies used copper and zinc as decontamination targets. Although there is much to be explored regarding the use of species from the Brazilian flora, the results are satisfactory, contribute to the advancement of knowledge, and already offer a significant amount of possible plant species for metals remediation.