Enzymatic Biomarker Responses of Channa punctata to Industrial Effluent Contamination in Freshwater River Ecosystems: A Review

Freshwater habitats in India are increasingly strained by the steady influx of industrial waste, a trend that has raised serious concern for the long-term health of aquatic organisms. The present review sets out to examine how key enzymatic biomarkers aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), and acid phosphatase (ACP) respond in Channa punctata when the fish are exposed to industrially contaminated rivers. To achieve this, research articles published between 2010 and 2024 were surveyed to trace changes in biochemical enzyme activity in populations inhabiting areas affected by effluents from paper and pulp units, tanneries, textile processing facilities, pharmaceutical industries, and mining operations rich in heavy metals. The review draws together evidence on seasonal behaviour of these biomarkers, variations between river systems, and the nature of disturbances associated with different categories of pollutants. Across the studies reviewed, increases in AST, ALT, and LDH were frequently reported, signalling tissue injury and altered metabolic function, while shifts in ALP and ACP pointed to disruptions in membrane activity and lysosomal processes. Taken together, these findings emphasise the sensitivity of C. punctata to complex industrial mixtures and reaffirm the usefulness of enzyme-based indicators in strengthening biomonitoring efforts across Indian freshwater ecosystems.