Evaluation of the genotoxic and cytotoxic effects of glyphosate-based herbicides in the ten spotted live-bearer fish Cnesterodon decemmaculatus (Jenyns, 1842)

Mortality, genotoxicity, and cytotoxicity of the 48% glyphosate-based formulations Panzer and Credit (R) were evaluated on Cnesterodon decemmaculatus (Jenyns, 1842) (Pisces, Poeciliidae) under laboratory conditions. Induction of micronuclei (MN) and alterations in the erythrocytes:erythroblasts ratio were employed as end points for genotoxicity and cytotoxicity, respectively. For Panzer (R), mean values of 16.70 and 15.68 mg/L were determined for LC50 at 24 and 96 h, respectively, and these concentrations reached mean values of 98.50 and 91.73 mg/L for Credit (R). LC50 values decreased as a negative linear function of Panzer (R) exposure time within the 0-96 h period, but not for Credit (R). LC50 values indicated that the fish were more sensitive to Panzer (R) than to Credit (R). Both 3.9 and 7.8 mg/L of Panzer (R) increased MN frequency at 48 and 96 h of treatment. When fish were exposed to Credit (R), an increased frequency of MN over control values was found after 96 h for all concentrations assayed, but not after 48 h. No cellular cytotoxicity was found after Panzer (R) and Credit (R) treatment, regardless of both the concentration and the sampling time. Furthermore, our results demonstrated that Panzer (R) and Credit (R) should be considered as glyphosate-based commercial formulations with genotoxic but not cytotoxic effect properties. (C) 2012 Elsevier Inc. All rights reserved.