Effects of the pharmaceutical contaminants ibuprofen, diclofenac, and carbamazepine alone, and in combination, on oxidative stress parameters in early life stages of tench (Tinca tinca)

In the present study, the effects of sub-lethal sub-chronic doses of ibuprofen, diclofenac, and carbamazepine alone, and in combination (concentration range 0.02-60 µg/l), on the early life stages of tench (Tinca tinca) were investigated. The lower concentrations of pharmaceuticals tested (0.02, 0.2, 2 µg/l) represent the concentration values of these substances commonly present in surface waters or effluents from wastewater treatment plants. Multiple biomarkers of biotransformation, antioxidant defence systems, and lipid peroxidation were determined in fish after 35 days of exposure. The evaluated pharmaceuticals induced oxidative stress in fish both alone and in combination with each other. Generally, 60 µg/l of each single pharmaceutical influenced the activity of antioxidant enzymes significantly (P < 0.05), whereas the same concentration of these pharmaceuticals in combination (1 : 1 : 1) did not have any impact on the activity of these enzymes. However, changes in biotransformation and antioxidant enzymes were apparent if lower concentrations of these pharmaceuticals were administered in the mixture. Significant changes (P < 0.05) in the activities of glutathione reductase, glutathione peroxidase, and glutathione-S-transferase were observed even at environmental concentration ranges. A significant effect (P < 0.05) on lipid peroxidation levels was found only in the experimental group exposed to carbamazepine.