Abstract
Tolyltriazole (TTA) is one of the contaminants detected in groundwater near major airports, necessitating further investigation into the fate and effects of this chemical. This study examined the impact of TTA on African catfish ( Clarias gariepinus ) and explored Chlorella vulgaris as a bioremediation agent. Five groups of fish were established, including four treatment groups and a control group: low-dose TTA (1.1 µg/L) group, low-dose TTA with C. vulgaris (1.1 µg/L TTA + 50 g/kg C. vulgaris ) group, high-dose TTA (2.2 µg/L) group, and high-dose TTA with C. vulgaris (2.2 µg/L TTA + 50 g/kg C. vulgaris ) group. The exposure period was two weeks. Moreover, neurological parameters—acetylcholinesterase (AchE), cortisol, and monoamine oxidase (MAO)—were evaluated. Exposure to TTA led to a significant increase in AchE in the low-dose TTA with C. vulgaris group and a substantial decrease in the high-dose TTA group. In contrast, there was a notable rise in cortisol only in the high-dose TTA group. In comparison with the control group, MAO significantly increased in each group. Superoxide Dismutase was markedly reduced only in the group receiving a high dose of TTA. Catalase and Total Antioxidant Capacity were substantially lower in all groups than in the control group, except for fish given a low dose of TTA with C. vulgaris . Furthermore, TTA exposure revealed seeral histopathological alterations, including hydropic degeneration, along with karyolysis and pyknotic nuclei. On the other hand, C. vulgaris treatment enhanced the regular liver configuration. In conclusion, exposure to TTA causes changes in neurological parameters, antioxidant capacity, and normal liver histology; nevertheless, chlorella supplementation guards against these adverse effects.