Effects of ecologically relevant concentrations of cadmium in a freshwater fish

•The effects of low concentrations of cadmium in the fish Rhamdia quelen were evaluated.•Low cadmium concentrations caused hepatotoxicity and nephotoxicity in silver catfish.•The hematological parameters were altered in silver catfish exposed to cadmium.•Lower cadmium concentrations caused damage to the health of Rhamdia quelen species.

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 100 μg L−1) for 15 days. Bioconcentration was observed in the liver of fish exposed to 10 and 100 μg L−1 of cadmium. The liver glutathione S-transferase activity decreased at 0.1 and 1 μg L−1 and increased at 100 μg L−1 and lipoperoxidation increased in all tested concentrations. Fish exposed to 0.1, 1 and 100 µg L−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 100 μg L−1. Neurotoxicity was not observed. The results showed that low concentrations (range of μg L−1) of Cd caused hepato-, nephro- and hematological alterations in this freshwater fish species.