Toxicidade do herbicida Paraquat em Colossoma Macropomu (CUVIER, 1818)

Abstract

The ecotoxicological study of any pesticide used in the environment is fundamental to the regulatory process and classification as to environmental risk potential. In the aquatic environment, agrochemicals can alter the physico-chemical variables of the water or be toxic to biota, and may interfere with the essential functions of this ecosystem through the reduction of species diversity. Paraquat is used for the control of terrestrial weeds and its presence is reported in many sources of water in the world, being widely used in Brazilian agriculture. Thus, investigating the toxicity of this herbicide in native fish, using toxicity tests, is important to evaluate the possible damages that the xenobiotic can cause. The objective of this work was to evaluate the effect of exposure of tambaqui to the herbicide paraquat for 96 hours (determining CL50-96H), genotoxic potential, hematological and biochemical parameters, histological integrity of the gill, liver and kidney in the concentrations: control, 10 mg L-1, 15 mg.L-1, 20 mg.L-1 and 25 mg.L-1, and at 7 and 15 days without exposure to paraquat (control, 10 mg.L-1, 15 mg.L -1). The herbicide caused genotoxicity (frequency of micronuclei and nuclear abnormalities) in exposed animals for 96 hours and in recoveries for 7 and 15 days. It was observed that the herbicide caused several histological damages in the gills (aneurysm), and it was observed that the herbicide did not reverse the damage caused by the herbicide. edema, cellular hypertrophy, hyperplasia), liver (cellular hypertrophy, nuclear degeneration, biliary stagnation, among others) and kidney (tubular lumen enlargement, tubular degeneration, tubular lumen obstruction) of exposed animals for 96 hours, and even after these changes remain.