Markers of pesticide exposure in irrigated rice cultures.

The objective of this research is to verify the genotoxicity caused by pesticides used in irrigated rice cultures in Araranguá city in the southern Brazilian state of Santa Catarina through the alkaline comet assay in peripheral blood of Geophagus brasiliensis and to analyze the toxicity of the water using Daphnia magna as sentinel organism. Three collections of water and fish were made in the main rice ditch, and one collection for the control group was taken in the Araranguá River. The toxicity test with D. magna and the comet assay followed protocols previously described. The toxicity factor for the control group and collections 1, 2, and 3 were, respectively, 0, 1, 0, and 2. The comet assay demonstrated significant differences just in collection 2, in comparison to the control group and collections 1 and 3. These results, despite significant statistical data, are not a biological problem, because the values were not so large but serve to warn of a possible disruption of the balance in this environment system.