Evaluation of Genotoxic Potential of Chromium (VI) in Channa punctata Fish in Terms of Chromosomal Aberrations

Abstract

Chromium, a widely recognized carcinogenic, mutagenic and redox active metal, is released into aquaticenvironments by electroplating, tannery and textile industries. Elevated concentrations in sediments and interstitialwaters are well documented. Fishes dwelling in chromium waste infested waters are presumed to be affected by itsdeposits. 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 asbiomarker of [Cr(VI)] induced toxicity. The fish were divided into three groups:Group I non-treated controls; groupII positive controls, treated with an intra-muscular injection of mitomycin-C at 1 mg/kg body wt; group III exposedto a sublethal concentration (7.689 mg/l) of [Cr(VI)], dissolved in the water. For CAT estimation, short term staticbioassays were conducted and samples were collected from the kidneys of fish after 24, 48, 72, 96 and 168 hrs ofexposure. 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 after72 hrs of [Cr(VI)] exposure. The present study, thus reveals that even for acute exposure, [Cr(VI)] is a genotoxicagent for C. punctata.