Ecotoxicological effects of conventional herbicides and a natural herbicide on freshwater fish ( Danio rerio ).

The contamination of aquatic environments has increased over time, affecting environmental integrity and human health. Herbicides represent a source of this contamination, and among the most commercialized are the triazines and glyphosate. In contrast, there are natural herbicides, which are less harmful to the environment. The aim of this study was to verify the ecotoxicological effects of the conventional herbicides (Atrazine and Glyphosate) and a natural herbicide on Zebrafish ( Danio rerio ). Fish were exposed for 72 h to different concentrations of conventional herbicides (1, 65, and 5,000 µg L ^-1 ) and the natural herbicide (0.62, 1.25, and 2.5 µg L ^-1 ) in aquaria (20 L). At end of the experiment, blood was collected from the fish, and slides were prepared to verify the frequency of nuclear abnormalities and micronuclei. A greater number of morphological nuclear alterations were recorded in the conventional herbicide treatments. In addition, significant differences were observed in the composition of abnormalities between treatments. Atrazine and Glyphosate can cause greater damage in D. rerio , demonstrating potential toxicity at all concentrations applied. The natural herbicide showed less mutagenic potential and was less harmful to fish. Thus, natural herbicides can be a better option for the preservation of the environment.