Impact of Industrial Heavy Metal Pollution on Fish Health and Toxicological Biomarkers in the Kanpur Stretch of the Ganga River

Abstract

Industrial pollution has emerged as one of the most critical environmental challenges affecting the ecological health of the Ganga River, particularly in the Kanpur stretch, which is recognized as a major industrial hub in Uttar Pradesh. Continuous discharge of untreated or partially treated effluents from leather tanneries, chemical industries, textile units, electroplating facilities, and urban sewage systems has led to elevated concentrations of heavy metals such as chromium (Cr), lead (Pb), cadmium (Cd), mercury (Hg), copper (Cu), and nickel (Ni) in aquatic environments. These metals persist in water and sediments, enter the aquatic food chain, and accumulate in fish tissues through bioaccumulation processes. The resulting exposure causes multiple toxicological effects in fish, including oxidative stress, enzymatic disruption, histopathological damage, immune suppression, and reproductive impairment. Toxicological biomarkers such as antioxidant enzyme activity, lipid peroxidation levels, acetylcholinesterase inhibition, and tissue alterations have been widely used to evaluate the physiological stress experienced by fish populations in polluted zones. This study reviews scientific findings related to heavy metal contamination, fish health status, and biomarker responses in the Kanpur stretch of the Ganga River. The analysis highlights clear relationships between industrial pollution intensity and biological stress indicators in fish, emphasizing ecological risks and potential implications for fisheries and public health. The study further underscores the importance of continuous monitoring, improved effluent treatment, and biomarker-based environmental assessment for sustainable river management.