ABSTRACT
In ecotoxicological research, fish are commonly used as sentinel organisms due to their pivotal roles in the food chain, ability to accumulate toxins, and sensitivity to even low levels of mutagens, making them ideal model for studies in toxicology and pharmacology. This study focused on the herbicide Paraquat dichloride and its impact on juvenil Clarias gariepinus. Water quality parameters ( pH, DO, BOD and Total dissolved solid) were within acceptable ranges for aquaculture, indicating they did not contribute to observed behavioral changes in the fish. Acute Toxicity Test, fish were exposed to different Paraquat dichloride 3ml,6ml,9ml and 12ml concentrations for 96 hours. Sub-Chronic Test, 0.4ml,0.6ml,0.8ml,1ml concentrations exposure occurred for 28 days. Histo-pathological and biochemical analyses revealed increased antioxidant enzyme activity, elevated ALT and AST levels, suggesting potential liver stress and tissue damage. Lower albumin levels hinted at possible liver dysfunction, while varied TB, SOD, CAT, and GPX levels indicated diverse responses to Paraquat-induced oxidative stress. The study found higher mortality at 78% and lower mortality at 26%, indicating a dosedependent relationship, increased mortality percentages were linked to Paraquat exposure, affecting fish survival and behavior. Paraquat toxicity to C. gariepinus varied with exposure time and concentration, emphasizing the importance of factors like age, size, and health. The study suggested using these antioxidants as biomarkers for contamination-related toxicity in freshwater fish. To mitigate herbicide effects on aquatic life, alternative practices like integrated pest management and less toxic herbicides are recommended. Developing herbicide-resistant crops could also reduce herbicide use.
