Heavy metal concentration and its toxicity assessment in some market fishes of Dhaka city

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.