Análise da fitorremediação como método de recuperação de áreas degradadas pela mineração: estudo do aguapé (Eichhornia crassipes) como hiperacumuladora de metais pesados

Abstract

Mining is present in humankind since ancient times. However, the problems generated by mining only received adequate attention from the middle of last century. Thus, a theme began to gain more attention from the scientific: Phytoremediation. A low cost method to clean areas contaminated and is currently widely used in sanitation systems for decontamination of water by organic compounds. However, this same method can be used to remove heavy metals that uses plants tolerant to poisoning, which remove and / or stabilize contaminants more simply and cheaply than conventional methods and allowing the recovery of these metals generating in certain cases Phytomining. To illustrate the amazonic region potential for this technology it was made the analysis of the water hyacinth (Eichhornia crassipes), native plant of the region, to determine if this specie possesses the absorption capacity of Cu, Pb, Ni and Fe. Three samples of water and water hyacinth were collected from Tocantins River at three different points in the vicinity of road and rail bridge in Marabá, PA. Plants were separated into parts (root, stem, leaf and flower), dried at 70 ° C for 150 hours and pre-treated with aqua regia (HCl:HNO3, 3:1) on hot plate and analyzed by Atomic Absorption Spectrometer, using the method of Flames. Of the thirteen samples only one showed nickel. The Water hyacinth has potential for hyperaccumulation of Cu and Pb, present in a given sample with 3.21 g of Cu per kilogram. These results are important because they show that there is the possibility of utilization the water hyacinth can be used to remove Cu from tailings ponds from mining areas, preventing local contamination and possibiliting the recovery of metal later by burning organic matter. This way was made evidence of more deep laboratorial studies to determine the best conditions to the absorption of Cu by the water hiacynth beyond to show the Phytoremediation like more one weapon against the degradation of mined areas, which needs more study because it is a very promising line of research in Brazil due to extensive existing flora.