PESTICIDE POLLUTION AND AQUATIC HEALTH: CYHALOTHRIN TOXICITY IN CYPRINUS CARPIO

Synthetic pyrethroid pesticides, with lambda-cyhalothrin (LCH) being the most frequently used, have been applied extensively in agriculture, but there is much concern about their possible ecotoxicological impacts on aquatic ecosystems. This investigates the sublethal paraphernalia of LCH on the bio-chemical, enzymatic, haematological, and histopathological parameters of Cyprinus carpio, a sentinel freshwater species. Under semi-static conditions, fish were exposed to a LCH effective concentration (1.6 µg/L) for 1, 5, 10, 15, and 20 days. Physiological response was assessed in multiple tissues, including the liver, gill, kidney, muscle, intestine, ovary, testis, and blood. Subsequently, it was found that there was time time-dependent decline in soluble, structural, and total protein concentrations with increased free amino acids, protease activity, indicating disturbed protein metabolism as determined by biochemical assays. Elevated acetylcholine levels and inhibited acetylcholinesterase activity were evidenced as neurotoxic effects. Osmoregulatory dysfunction was manifested as ionic imbalance and suppressed activities of Na⁺/K⁺, Ca²⁺, and Mg²⁺ ATPases. It was found that antioxidant enzymes activities (catalase, SOD, GPx, GST) were reduced while malondialdehydes levels were increased, which indicates oxidative stress. There were signs of hepatic injury in the serum AST, ALT, and ALP. Haematological analysis showed marked decreases in RBC and hemoglobin as well as increased WBC counts consistent with anemia and immune stress. Biochemical findings were validated by histopathological changes of necrosis and cellular degeneration, not only in the kidneys, but also in other organs. However, these results underscore the fact that even sublethal exposure to LCH can result in systemic toxicity in fish and thus present serious ecological risks. Ensuring environmentally friendly ‘preparedness’ and scrutinised pesticide regulation is vital to protecting aquatic life from pesticide exposure, the study concluded.