RESUMO
Sub-chronic effects of ecologically relevant concentrations of cadmium (Cd) were evaluated in the catfish Rhamdia quelen. The fish were exposed to Cd (0, 0.1, 1, 10 and 100µgL(-1)) for 15 days. Bioconcentration was observed in the liver of fish exposed to 10 and 100µgL(-1) of cadmium. The liver glutathione S-transferase activity decreased at 0.1 and 1µgL(-1) and increased at 100µgL(-1) and lipoperoxidation increased in all tested concentrations. Fish exposed to 0.1, 1 and 100µgL(-1) Cd presented increase in hepatic lesion index. In the kidney, the catalase activity and LPO reduced in all exposed groups. The gluthatione peroxidase, etoxiresorufin-O-deethylase activities and metallothionein increased at the highest concentration of Cd, but the level of reduced glutathione decreased. The genotoxicity was observed at 0.1 and 100µgL(-1). Neurotoxicity was not observed. The results showed that low concentrations (range of µgL(-1)) of Cd caused hepato-, nephro- and hematological alterations in this freshwater fish species.