Chlorpyrifos‐based insecticides induced genotoxic and cytotoxic effects in the ten spotted live‐bearer fish,Cnesterodon decemmaculatus (Jenyns, 1842)

Mortality, genotoxicity, and cytotoxicity of the 48% chlorpyrifos (CPF)‐based formulations Lorsban* 48E^® and CPF Zamba^® were evaluated on Cnesterodon decemmaculatus (Jenyns, 1842) (Pisces, Poeciliidae) under laboratory conditions. Induction of micronucleus (MN) and alterations in the erythrocyte/erythroblast frequencies were employed as end points for genotoxicity and cytotoxicity, respectively. For Lorsban* 48E^®, mean values of 0.13 and 0.03 mg/L were determined for LC₅₀ at 24 and 96 h, respectively, and these concentrations reached mean values of 0.40 and 0.21 mg/L for CPF Zamba^®. Mortality values increased as a positive linear function of the CPF Zamba^® concentrations, but not for Lorsban* 48E^® concentrations. There was no significant relationship between mortality and exposure time within the 0–96 h period for both formulations. LC₅₀ values indicated that the fish were seven fold more sensitive to Lorsban* 48E^® than to CPF Zamba^®. Lorsban* 48E^® within the concentration range of 0.008–0.025 mg/L increased MN frequency at both 48 and 96 h of treatment. Similar results were also observed when fish were exposed to 0.052–0.155 mg/L of CPF Zamba^®, regardless of the exposure time. Cellular cytotoxicity was found after Lorsban* 48E^® and CPF Zamba^® treatments for all concentrations and time exposures, estimated by a decrease in the frequency of mature erythrocytes and a concomitant enhanced frequency of erythroblasts in circulating blood. Furthermore, our results demonstrated that Lorsban* 48E^® and CPF Zamba^® should be considered as CPF‐based commercial formulations with marked genotoxic and cytotoxic properties. © 2013 Wiley Periodicals, Inc. Environ Toxicol 29: 1390–1398, 2014.