Evaluation of genotoxic potential of chromium (VI) in Channa punctata fish in terms of chromosomal aberrations.

Chromium, a widely recognized carcinogenic, mutagenic and redox active metal, is released into aquatic environments by electroplating, tannery and textile industries. Elevated concentrations in sediments and interstitial waters are well documented. Fishes dwelling in chromium waste infested waters are presumed to be affected by its deposits. To evaluate the genotoxic potential of chromium [Cr(VI)] on aquatic bio-system, bottom feeding fishes, Channa punctata, as model fish, were exposed to [Cr(VI)]. The chromosomal aberration test (CAT) was used as biomarker of [Cr(VI)] induced toxicity. The fish were divided into three groups:Group I non-treated controls; group II positive controls, treated with an intra-muscular injection of mitomycin-C at 1 mg/kg body wt; group III exposed to a sublethal concentration (7.689 mg/l) of [Cr(VI)], dissolved in the water. For CAT estimation, short term static bioassays were conducted and samples were collected from the kidneys of fish after 24, 48, 72, 96 and 168 hrs of exposure. The remarkable chromosomal aberrations recorded in the present investigation included chromatid breaks, chromosome breaks, chromatid deletions, fragments, acentric fragments, and ring and di-centric chromosomes, along with chromatid and chromosome gaps. A significant increase in chromosomal aberrations was observed after 72 hrs of [Cr(VI)] exposure. The present study, thus reveals that even for acute exposure, [Cr(VI)] is a genotoxic agent for C. punctata.