Estudo da biodegradação anaeróbia do herbicida 2,4-D sob diferentes condições de oxirredução

Abstract

Brazil is one of the countries that most uses herbicides in the world. Its indiscriminate use generates adverse effects on the environment and health. 2,4-Dichlorophenoxyacetic acid is among the 3 most used pesticide active principles in Brazil and is used in several crops. It can be found in surface and deep soils, sediments of rivers, lakes, seas, rivers and groundwater. The aerobic process of biodegradation of this herbicide is known and well reported in the scientific literature, however little is known about the anaerobic process of degradation of this compound. This work proposes to deepen the studies related to the anaerobic degradation of 2,4-D. Thus, the present study aimed to analyze the degradation of 2,4-D under different oxidation-reduction conditions. For this, enrichment tests of the anaerobic methanogenic, sulfate-reducing and denitrifying microbial communities were carried out in the presence of 2,4-D, using the sediment collected in the Itaipú reservoir as inoculum. The results of the tests indicate that there was a variation in the removal of 2,4-D between the different oxidation-reduction media, being 9.26% for the denitrifying condition, 63.33% for the sulfetogenic condition and 100% in the medium for the methanogenic condition. Therefore, the methanogenic medium presented the best conditions for the remediation of the 2,4-D herbicide under the conditions studied. The results presented may contribute to a more complete analysis of the behavior of this compound in the environment, helping to develop more efficient bioremediation processes.