Pesticides-induced histopathological and biochemical alterations in fish: Impacts and restoration strategies

The extensive application of pesticides in urban and agricultural areas contaminates surface water. When these substances enter aquatic environments through runoff, they can cause various abnormalities in fish species. The most commonly used pesticides in agricultural farmlands and urban environments are herbicides, fungicides, and insecticides. Although pesticides are beneficial for agricultural production, they have been shown to pose significant hazards to both human health and the environment. These chemicals have a high potential for bioaccumulation, environmental persistence, and toxicity. The degradation rate of pesticides can vary from a few hours to several days or even years, depending on environmental conditions and their chemical composition. However, pesticides induce various biochemical alterations, particularly changing the enzymatic activity, including alkaline phosphatase (APT), alanine aminotransferase (ALT), aspartate aminotransferase (AST), succinate dehydrogenase (SDH), peroxidase, catalase (CAT), and superoxide dismutase (SOD). Additionally, pesticides induce histopathological changes in organs such as the gills, brain, liver, kidneys, intestine, and muscles. These histopathological alterations include pyknosis, cytoplasmic infiltrations, changes in the primary and secondary lamellae, lesions and deformities, tissue degeneration, atrophy, hyperplasia, congestion, necrosis, and apoptosis. Various techniques have been employed to control the effects of pesticides on fish species, including water treatment methods, hybrid technologies, and bioremediation approaches. Water treatment methods for pesticide removal include photo-fenton, chlorination, nanotechnology, and adsorption. Hybrid technologies include ultrafiltration and coagulation treatments, advanced oxidation processes (AOPs), and photochemical degradation. Furthermore, bioremediation strategies, often combined with advanced technologies, are being employed to minimize pesticide pollution. This review highlights the effects of various pesticides on the histopathological and biochemical alterations in farmed fish, as well as potential strategies for mitigating pesticide contamination.