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

Abstract

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.