Investigation of toxic effects of fungicide tebuconazole on freshwater mussels (Unio mancus) with multiple biomarkers

Triazole fungicides are widely used as broad-spectrum, non-steroidal antiestrogens and for various industrial applications. Residues of these fungicides are found in environments such as soil and water, and in the tissues of living organisms. Increasing toxicity reports have led to the emergence of triazole fungicides as pollutants of environmental and public health concern. In this study, the toxic effects of tebuconazole (TEB), one of the most widely used triazole fungicides, on freshwater mussels (Unio mancus), which are non-target organisms, were investigated. In the study, various oxidative stress parameters [total antioxidant concentration (TAC), total oxidant concentration (TOC), oxidative stress index (OSI), glutathione (GSH), malondialdehyde (MDA)], antioxidant enzymes [(superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR)] and carboxylesterase (CaE) activity from biotransformation enzymes was evaluated in the gill and digestive glands of mussels exposed to four TEB concentrations (1.5, 15, 150 and 1500 µg AI L-1) for 96 hours. It was observed that TEB exposure significantly increased TAC, OSI, MDA levels, decreased TOC and GSH levels, increased SOD, GPx, GST activities, and inhibited GR and CaE activities in both the gill and digestive gland compared to the control. As a result, it can be said that TEB has significant toxic effects on U. mancus and mussels living in freshwater ecosystems may be under the threat of TEB exposure.