Author: Pralay Mahapatra
DOI Link: https://doi.org/10.70798/Bijmrd/03120003
Abstract: Heavy metal contamination of freshwater ecosystems has emerged as a major environmental concern due to its persistence, bioaccumulative nature, and adverse biological effects. Among these metals, nickel (Ni) occupies a unique position as an essential trace element at low concentrations but becomes highly toxic when present beyond permissible limits. Industrial effluents, mining activities, agricultural runoff, and fossil fuel combustion are primary contributors to nickel enrichment in aquatic environments. Fish, owing to their ecological relevance and sensitivity to pollutants, serve as reliable bioindicators of metal-induced toxicity. Channa punctatus, a widely distributed freshwater teleost in the Indian subcontinent, has been extensively employed in ecotoxicological investigations due to its adaptability and well-characterized physiology.
This mini review synthesizes current knowledge on the toxic effects of nickel in freshwater fish, with particular emphasis on biochemical alterations and histopathological damage reported in Channa punctatus. The review highlights the influence of physicochemical water parameters on nickel bioavailability, summarizes reported LC₅₀ values, and discusses oxidative stress–mediated biochemical disruptions in liver tissues alongside structural damage in gills. By integrating biochemical and histopathological biomarkers, this review underscores their utility in early detection of sub-lethal nickel toxicity and environmental monitoring. The paper also identifies key research gaps and future directions for developing biomarker-based frameworks for freshwater ecosystem risk assessment.
Keywords: Nickel Toxicity, Freshwater Fish, Channa punctatus, Oxidative Stress, Histopathology, Aquatic Ecotoxicology.
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