European Journal of Zoological Research
Abstract
Author(s): Udiba U. U., Odey M. O., Gauje B., Ezike N. N., Aribido O. S., Otori M.,
Umar S., Ashade N.
Concentration of some heavy metals; Lead (Pb), Copper (Cu) and Zinc (Zn), in the head, gills, liver and muscle
tissues of Clarias gariepinus from River Galma, River Kubanni and some fish farms in Zaria, Nigeria, were
determined using atomic absorption spectrophotometer (AAS), after wet digestion. The concentration of the metals
differed significantly (ANOVA; p < 0.05) among the four fish tissues. Fish liver and gills appeared to have
significantly higher tendency for the accumulation of these metals, while muscles had minimum concentrations. The
difference in metal concentrations between the three locations were not statistically significant (ANOVA; p > 0.05),
the difference of lead concentration between River Galma and fish farms being the only exception. The trend of
metals concentration could be represented as: Cu > Zn > Pb. The mean of total concentrations was; lead 1.55
mg/kg, zinc 3.57 mg/kg, copper 5.75 mg/kg for River Galma, lead 0.5 mg/kg, zinc 3.86 mg/kg, copper 5.75 mg/kg for
River Kubanni and lead 0.28 mg/kg, zinc 1.0 mg/kg , copper 5.21 mg/kg for fish farms. Comparison of these values
with Food and Agricultural Organization (FAO) limits in fish tissue, Codex Committee on Food Additives and
Contaminants maximum levels (CCFAC) and Health criteria established by the United States Environmental
Protection Agency (US EPA) for human health risk for carcinogens shows that it is unsafe to consume Clarias
griepinus tissues from River Galma and River Kubanni with respect to lead toxicity. Copper and zinc were however
not implicated in the study.
