Avaliação da capacidade de Eleocharis mutata (L.) Roem. & Schult. na fitoextração de cromo III

Abstract

Liquid waste generated in industrial processes have different pollutants and contaminants that cause significant environmental impacts. Therefore, the Brazilian legislation establishes in its CONAMA Resolution No. 430/2011 effluent discharge standards into rivers. One of the elements that damage the environment and so has its release controlled is chromium (Cr), a very corrosion-resistant metal and abundant on the globe. An important Chrome use in the industry is in leather processing, where it is used to transform the skin leather rot. For this, chromium solutions are used and, after the tanning process, requires treatment before being discarded. An economical alternative to conventional treatments is the use of living organisms to immobilize or degrade pollutants. Inside this context, we have the phytoremediation that consists in using plants to improve the physicochemical characteristics of an effluent. This study aimed to analyze the trivalent chromium absorption by Eleocharis mutata (L.) Roem. & Schult. To this was mounted on an experiment with E. mutata specimens immersed in trivalent chromium solution of 200 mg / L. The experiment was conducted in duplicate and it was divided into time slots 6h, 12h, 24h, 48h, 72h and 96h. In each interval, the macrophyte was removed, identified and stored for later sent for chemical analysis. To interpret the results statistical tests were performed in BioEstat 5.0 program to determine the correlation coefficient between time and concentration of chrome in solution in leaves and roots of macrophyte. The roots were the ones that showed the highest chromium absorption values with 4,170 grams of chromium per kg. The leaves showed no significant results for the statistical test. Despite the proven chromium absorption, the final efficiency of treatment was only 32%, showing that the macrophyte is resistant chromium but is not an efficient phyto remediation. Besides the low efficiency, it was found that after 96 hours of immersion in the solution macrophyte showed signs of senescence due to metal poisoning.