Evaluation of the Impact of Selected Metallic Contaminants on Wild Rutilus rutilus Through Integrated Antioxidant Biomarker Responses

The application of biomarkers is often used to better understand the assessment of the toxicity in aquatic organisms within their natural environment. To this end, we examined the gills and liver of roach (Rutilus rutilus) to measure changes in the activity of the antioxidant enzymes superoxide dismutase, catalase (CAT), glutathione peroxidase, glutathione reductase and the phase II biotransformation enzyme glutathione-S-transferase (GST), as well as changes in the concentration of lipid peroxides (LPOs). Roach were collected at two localities, Veliko Ratno ostrvo and Višnjica (VIS), on the Danube River, where the concentrations of dissolved metals (Cu, Cd, Zn, Fe, Mn, Hg, Ni, As, Pb) in both fish tissues were quantified. This paper describes the integrated reaction of antioxidant enzymes and LPO levels of roach from two sampling localities in the Danube River. Principal component analysis revealed obvious differences of the antioxidant biomarkers investigated between tissues and localities, while integrated biomarker response showed that the liver of the VIS locality had the stronger antioxidant biomarker response. Despite the concordant hypothesized antioxidant induction at the VIS locality in both tissues studied, the effects as a sign of contaminant exposure appear to be mediated in part by suppression of the antioxidant system, with CAT and GST as potential candidate tissue toxicity biomarkers of contaminants.