Evaluation of Levels of Cd, Cr, Pb and Zn in Crayfish, Tilapia zilli and Clupea harengus from Nigeria

摘要

Some heavy metals such as Cd, Cr, Pb and Zn from Cray fish, Smoked Clupea harengus, Frozen Clupea harengus and Tilapia Zilli from Makurdi, Nigeria were assessed. The results showed concentrations (mg/kg) of Cd, Cr, Pb and Zn in smoked Clupea harengus as: 0.028, 1.892, 0.045 and 0.434 respectively. For Cd, Cr, Pb and Zn the values were: 0.013, 1.425, 0.319 and 0.253 respectively in frozen Clupea harengus. For Tilapia zilli, the mean values (mg/kg) of Cd, Cr, Pb and Zn were; 0.025, 2.205, 0.111 and 0.181 respectively. For Crayfish, the results were 0.010, 0.222, 0.498 and 1.119 for Cd, Cr, Pb and Zn respectively. The levels of the metals in these samples all fell below the permissible limits set by regularity bodies. In view of the fact that the high levels of these heavy metals potent health hazard, routine monitoring is required in order to detect any outrageous amount of these metals in these fish species as they have shown potential as bio indicators for environmental monitoring of heavy metals.