Effects of a nicosulfuron-based herbicide on common carp <i>(Cyprinus carpio)</i> under laboratory conditions: pathophysiological and histopathological evaluation

Abstract Introduction Contamination with herbicides is a frequent environmental issue. The aim of the study was to evaluate haematological and blood biochemical parameters, and the microstructure of selected organs in control and herbicide-exposed fish. Material and Methods In this study, 108 common carp ( Cyprinus carpio ) were exposed to a commercial herbicide with nicosulfuron as its active substance. Three groups of fish were established: control, TAM1 (nicosulfuron at 1 mg/L), and TAM2 (nicosulfuron at 5 mg/L). Treatment lasted 1, 3 or 10 days. Functional (pathophysiological) and structural (histopathological) alterations in control and herbicide-exposed fish were evaluated. Results Various haematological changes and some biochemical alterations were detected. The pathophysiological changes suggested erythrocyte damage, compensatory response (as indicated by an increase in red blood cell count and erythroblast percentage), stress response (as evidenced by an increase in glucose concentration) and possible lipid metabolism disorders (as indicated by a decrease in cholesterol concentration). More differences in pathophysiological parameters were detected between TAM2 fish and control fish than between TAM1 fish and control fish. Histopathological analysis revealed renal tubule necrosis, of which the severity depended on herbicide concentration and exposure duration. Conclusion The exposure of common carp to the tested nicosulfuron-based herbicide formulation led to pathophysiological and histopathological alterations, indicating the need for systematic detection and quantification of nicosulfuron in aquatic environments.