Sublethal exposure of heavy metals induces micronuclei in fish, Channa punctata

Present studies were designed to evaluate toxic potential of three common heavy metals, adequately present in agro-industrial effluents, viz. mercury, arsenic and copper using in vivo micronucleus assay in an actinopterygiian fish, Channa punctata (2n = 32). Ten days laboratory acclimatized fishes were divided into five groups. Groups I and II served as negative and positive controls, respectively and fishes of group III–V were subjected uninterrupted to sublethal concentrations (10% of 96 h LC50) of heavy metal compounds, HgCl2 (0.081 mg L−1), As2O3 (6.936 mg L−1) and CuSO4·5H2O (0.407 mg L−1) for 24, 48, 72, 96 and 168 h of exposure periods. Significant increase over and above negative control in the frequency of micronuclei was observed in fishes exposed to metal compounds. The average frequency of micronuclei in fishes exposed to Hg(II), As(III) and Cu(II) observed was 9.79, 12.03 and 8.86, respectively. It reveals that the order of induction of micronuclei frequency and toxicity was As > Hg > Cu. Findings depict genotoxic potential of these metal compounds even in sublethal concentrations.