IMPACT OF AQUATIC POLLUTION ON PHYSIOLOGICAL, BIOCHEMICAL, AND MORPHOLOGICAL RESPONSES IN ANIMALS

Abstract

Aquatic pollution is a major environmental threat that can adversely affect fish health at physiological, biochemical, morphological, and behavioral levels. The present study evaluated the effects of increasing aquatic pollution on fish health using an integrated set of growth, behavioral, hematological, biochemical, oxidative stress, and histopathological indicators. Fish were exposed to control, low, moderate, and high pollution conditions for 30 days. Increasing pollution resulted in marked deterioration of water quality, with dissolved oxygen decreasing from 7.21 to 4.72 mg/L, while BOD increased from 2.4 to 10.2 mg/L and ammonia from 0.18 to 0.82 mg/L. Final body weight declined from 78.6 to 59.8 g, and weight gain decreased from 26.2 to 7.3 g under high pollution. RBC, hemoglobin, and hematocrit declined by approximately 30%, 27%, and 27%, respectively. In contrast, glucose increased by 52.5%, while ALT and AST increased by 98.9% and 69.4%, respectively. Oxidative stress was evident from a 104.7% increase in MDA and a 36.3% reduction in GSH under high pollution. Histopathological damage increased progressively, with the highest score observed in gills (3.6), followed by liver (3.2), kidney (2.8), and intestine (2.5). External abnormalities and behavioral disturbances also became more pronounced with increasing pollution intensity. Overall, the findings demonstrate that aquatic pollution produces concentration-dependent multisystem toxicity in fish, with gills representing the most sensitive organ. The combined use of water-quality parameters, behavioral responses, hematological and biochemical biomarkers, oxidative stress indicators, and histopathology provides an effective approach for assessing pollution-induced fish health deterioration.