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.