Biochemical and hematologic changes and accumulation in tilapia by exposure to herbicides mixture of the sugarcane culture

Abstract

Herbicides are widely used in agriculture, known as diffuse sources of pollution of surface water and groundwater. The impact of this use on water quality, however, is little known and has been the subject of studies around the world. It has already been observed mutagenic and genotoxic effects in fish exposed to herbicides. The predominant crop in the state of Sao Paulo is the sugarcane, comprising approximately five million hectares and an annual production of 328 million tones. The mixture of herbicides in the spray tank is a common practice among producers, although it is prohibited by law. Therefore, the aim of this study is to evaluate the toxicity of mixtures of tebuthiuron, ametrin and the commercial product Velpar K (diuron and hexazinone), widely used in sugarcane cultivation for tilapia, through studies of exposure in short and long term. It will be also evaluated biomarkers related to exposure to herbicides: hematological and biochemical analysis and bioconcentration factor in fish. The LC50-96h of mixtures will be calculated using the Probit Analysis and the evaluation of biochemical and hematological parameters by the module "One Way ANOVA, both of the program STATGRAPHICS PLUS 5. The level of significance will be established as P<0.05. We hope with the present results it will be possible to determine the toxicological potential of mixtures of herbicides tested for tilapia, reviewing, where appropriate, their use in crop management of sugarcane. We also hope that collected data will help the establishment of maximum allowed concentration of contaminants in water compartments in order to protect aquatic communities and public health. The later is a potential consumer of contaminated source of protein supplied by fish. (AU)