~ 523 ~ International Journal of Fisheries and Aquatic Studies 2016; 4(3): 523-527 ISSN: 2347-5129 (ICV-Poland) Impact Value: 5.62 (GIF) Impact Factor: 0.352 IJFAS 2016; 4(3): 523-527 © 2016 IJFAS www.fisheriesjournal.com Received: 15-03-2016 Accepted: 16-04-2016 A Hossain Department of Zoology, University of Dhaka, Dhaka- 1000 Bangladesh. MM Rahman Department of Zoology, University of Dhaka, Dhaka-1000. B Saha Biological Research Division, Dhaka Laboratories, BCSIR, Dhaka -1205 Bangladesh. M Moniruzzaman Biological Research Division, Dhaka Laboratories, BCSIR, Dhaka -1205 Bangladesh. M Begum Biological Research Division, Dhaka Laboratories, BCSIR, Dhaka -1205 Bangladesh. Correspondence M Begum Biological Research Division, Dhaka Laboratories, BCSIR, Dhaka -1205 Bangladesh. Heavy metal concentration and its toxicity assessment in some market fishes of Dhaka city A Hossain, MM Rahman, B Saha, M Moniruzzaman and M Begum Abstract In the present study, concentration of some bio-accumulated heavy metals (Cd, Cr, Ni, Fe, Mn and Pb) in four farm raised species of fishes, namely Pangasius hypophthalmus, Anabas testudineus, Oreochromis niloticus and Wallago attu were investigated collecting from different markets of Dhaka city. Among the six heavy metals tested, Fe was maximally accumulated, followed by Ni, Mn, Cr and Cd in flesh and liver of fishes. The concentration of Pb was below the detectable level (BDL) in all fishes. The overall highest concentration (mg/kg) of metals in flesh of all examined fishes were- Cd (0.775 mg/kg) and Cr (12.675 mg/kg) in A. testudineus, Ni (221.792 mg/kg), Fe (331.050 mg/kg) and Mn (17.842 mg/kg) in O. niloticus respectively. In liver, the highest concentration of five heavy metals were- Cd (1.433 mg/kg) and Cr (51.590 mg/kg) in O. niloticus, Ni (278.966 mg/kg) in W. attu, Fe (666.262 mg/kg) in O. niloticus and Mn (50.317 mg/kg) in A. testudineus. The values of all selected metals in fish samples considerably exceeded the maximum permissible limits of heavy metals for fish tissues as prescribed by various international agencies (FAO, WHO and IAEA) which indicate the acute heavy metal contamination in studied fishes. Therefore, the biological monitoring of the water and fish for heavy metal contamination should be done regularly and necessary steps must be taken to mitigate this contamination considering the human health safety issues. Keywords: Heavy metals. Toxicity test, Market fishes. 1. Introduction Fishes are major part of the human diet and therefore the studies on metal pollution in different species of edible fish are very essential regarding the fish consumption by human being. The heavy metals gain access into the aquatic environment from natural and anthropogenic sources and bio-accumulate in fish and other aquatic animals and rather than sedimentations in water [1] . Toxic heavy metals in the aquatic environment enters either directly from drinking water or indirectly through the food chain and have been implicated in many human health problems such as cancer, brain damage and various behavioral problems [2] . Studies carried out on fish have shown that heavy metals may have toxic effects, altering physiological activities and biochemical parameters both in tissue and in blood of fish [3] . The consequence of heavy metal pollution can be hazardous to human being by consuming such contaminated food. Therefore, it is important to monitor heavy metal in aquatic environments (water, sediment and biota). Recent reports have shown that farmed salmon, trout and shrimp can be contaminated with a range of contaminants including heavy metals, polychlorinated dibenzo-p-dioxins and –furans (PCDD/Fs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), and residues of antibiotics [4-8] . There have been remarkable numbers of studies done on heavy metal contamination in water, sediments and fish throughout the world. Some research works related to this works have been done in different part of the world [9-16] . In Bangladesh the concentration of heavy metals in fish, water and sediment has been studied by some authors but some works are prominent [17-24] . They investigated the concentration of different heavy metals in specific rivers or in specific organisms but there is no complete study on heavy metal concentration in market fishes. There is limited information available on the contamination of heavy metals in farmed raised fish which are cultured using polluted water and different types of artificial feeds. Therefore, the present study was conducted to determine the concentrations of Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni), Iron (Fe) and Manganese (Mn) in selected farm-