Avaliação da fitorremediação do propanil e 3,4-DCA por Pistia stratiotes

Abstract

The propanil is among the three most commonly used pesticides in rice cultivation. In just days this herbicide is degraded to 3,4-dichloroaniline (3,4-DCA) which is much more persistent and has a higher acute toxicity. Because of the wide use of the herbicide in rice culture, it is necessary to find ways of removing this compound in order to combat environmental contamination. Therefore, phytoremediation comes as a low-cost technique for removing these substances. This technique consists in using plants to degrade or sequester organic and inorganic pollutants being many times more efficient than conventional remediation. In that way the objective of this study was to evaluate the phytoremediation of propanil and 3,4-DCA by Pistia stratiotes. The presence of compounds was analyzed by high- performance liquid chromatography with diode array detection (HPLC-DAD). For the evaluation of phytoremediation two changes of P. stratiotes were treated with solutions containing 10 mg of L-1 propanil and 7.4 mg L-1of 3,4-DCA during the period of 14 days. On the 14th day it has not been possible to quantify the propanil in the control and treatments addition to being observed to decline in the concentration of 3,4-DCA produced by degradation of the propanil. In the samples treated only with 3,4-DCA also was possible to observe the degradation of the metabolite during the analysis period. The culture of Pistia stratiotes showed to be an effective and low-cost strategy for the phytoremediation of contaminated water by propanil and 3,4-DCA.