Mixture of herbicides applied in sugarcane crops: toxicity for tropical fish

Abstract

Herbicides are the most common pesticides used in agriculture, but the impact of this practice on non-target organisms is not well known. In the environment, herbicides are rarely alone, but almost no information is available on their toxicity combined, which makes the study of mixtures, particularly relevant. The herbicide mixture in the spray tank is a common practice among farmers, although it is prohibited by law. The predominant crop in the State of Sao Paulo is sugarcane, comprising approximately five million hectares. The objective of this study is to evaluate the effect of the mixture of herbicides ametryn and diuron + hexazinone, widely used in sugarcane crops, to the tropical cyprinid zebrafish (Danio rerio), through studies of exposure in the short and long term. The LC50-96h of single and mixture herbicides will be calculated using the statistical package Sigma Plot 11.0. The effective concentrations (EC50) for each endpoint will be determined with the aid of the spreadsheet ToxCalc, built-in Microsoft Excel software. The level of significance will be established as P <0.05. We hope with the present results it is possible to determine the toxicological potential of a mixture of herbicides ametrine, diuron, and hexazinone to tropical fish, evaluating, where appropriate, their use in sugarcane crop management. We also hope to provide information to assist in the establishment of maximum permissible concentrations of contaminants in water bodies, in order to protect aquatic communities.(AU)