Indian Journal of Experimental Biology Vol. 53, July 2015, pp. 476-483 Assessment of pollution of river Ganges by tannery effluents using genotoxicity biomarkers in murrel fish, Channa punctatus (Bloch) NS Nagpure, Rashmi Srivastava, Ravindra Kumar*, Anurag Dabas, Basdeo Kushwaha & Pavan Kumar Molecular Biology and Biotechnology Division, ICAR-National Bureau of Fish Genetic Resources, Lucknow-226 002, Uttar Pradesh, India Received 24 January 2014; revised 23 April 2014 River pollution due to rapid industrialization and anthropogenic activities adversely affects the aquatic organisms, especially fish. Here, we assessed the genotoxicity, mutagenicity and bioaccumulative aspects of tannery effluents in freshwater murrel, Channa punctatus, an inhabitant of river Ganges. Test specimens were collected from three different polluted sites of the river within and nearby Kanpur area during different seasons and blood samples of these specimens were processed for comet assay and micronucleus test as genotoxicity biomarkers. A significantly ( P <0.05) higher micronuclei induction, nuclear abnormalities and % tail DNA was observed in the specimens collected from the polluted sites. Bioaccumulation studies in the muscle (1.202 µg/g) and gill tissues (<0.300 µg/g) of the specimens revealed the concentration of chromium (core component of tanning industry) above the maximum permissible limits as prescribed by World Health Organization (WHO). The findings of the present analysis indicated contamination of river Ganges with tannery effluents which induce genotoxicity in fish with seasonal variation. Keywords: Aquatic pollution, Bioaccumulation, Channa punctatus, Ganga, Leather industry, Spotted snakehead. Industrial effluents containing toxic and hazardous substances, including heavy metals considerably pollute the aquatic ecosystem 1 . Among the different industrial units, the leather tanning industries pose a major problem as their treated/untreated tannery effluents containing heavy metals, especially chromium, cause genotoxic, mutagenic and carcinogenic effects in aquatic organisms and thereby to humans 2 . Tannery effluents remain as one of the highest pollutants among all the industrial wastes 3 . Chromium (Cr) is a scarce metal and its presence in the aquatic ecosystem is generally low 4 . However, natural water receives Cr from anthropogenic sources viz. industrial effluents, gets polluted, and thus become harmful to aquatic organisms 5 . Chromium toxicity is affected by species, body size and life stage of the organism as well as the pH of the water and, to a lesser extent, by hardness, salinity and temperature 6 . Chromium (VI) passes readily through the gill membrane and accumulates rapidly in various tissues at higher levels than in the gills 7 , including the brain, gall bladder, gastro-intestinal tract, intestine, kidney, opercular bone, spleen and stomach 8 . Hexavalent chromium is one of the trace elements in biological system necessary for glucose tolerance in mammals 9 and serum cholesterol level suppression 10 . However, above the permissible limits, it affects physiological performance of the body. Hexavalent chromium penetrates into the cells in the surface transport system, gets reduced to trivalent chromium and further, induces genotoxic effects in the cell 11,12 . Several studies have revealed that heavy metal chromium and its compounds lead to DNA damage through DNA single- and double-strand breaks resulting in chromosomal aberrations, sister chromatid exchanges, micronuclei & DNA adducts formations, as well as alterations in DNA replication & transcription 13-15 . The evaluation of genotoxic effects of metals in terrestrial and aquatic ecosystems by studying such effects on the animals from the respective habitats has been an established procedure among the researchers 16 . Studies on metal pollution in different edible fish species are not uncommon 17,18 . Industrial effluents, agricultural runoffs, and domestic waste pollute the water bodies with heavy metals which thereby enter into the food chain and the bioaccumulation processes (http://www.eoearth.org/view /article/152839/; http://www2. epa.gov/nutrientpollu- —————— *Correspondence: Phone: +91 522 2442440, 2442441; Fax: +91 522 2442403 E-mail: ravindra.scientist@gmail.com