Heavy metals (Hg, Pb and Cd) assessment in Nile Fish Oreochromis niloticus and Clarias lazera

Abstract

Heavy metals are one of the most important pollutants that affect the aquatic environment and fish. The present study was carried out on 40 random samples of Nile fish represented by Oreochromis niloticus and Clarias lazera (20 of each) were collected from several fish markets in Shibin El-kom, El-Menoufia, Egypt. These samples were promptly assigned to the laboratory for analysis of their mercury (Hg), lead (Pb), and cadmium (Cd) content. The mean contents of metal, expressed in mg/kg wet weight, varied from 0.46 ± 0.05 in Oreochromis niloticus and 0.69 ± 0.07 in Clarias lazera for Hg, 0.29 ± 0.03 in Oreochromis niloticus and 0.44 ± 0.05 in Clarias lazera for Pb and 0.13 ± 0.01 in Oreochromis niloticus and 0.21 ± 0.01 in Clarias lazera for Cd. The permissible limit by E.O.S in mg/kg for Hg is 0.50 ,for Pb is 0.30 and for Cd is 0.10 .Treatment of fish fillet by different acetic acid concentrations (1%), (3%), (5%) for 5 min; resulted in noticeable reduction of heavy metals by percentage in treated group fish compared with the untreated group, mercury reduced by8.1, 17.4 and 32.6, respectively, while lead reduced by 12.3, 26.2 and 38.5, respectively, and finally cadmium reduced by 17.3, 28.9 and 46.2, respectively. The public health importance of heavy metals was discussed.