ABSTRACT

The effect of different concentrations of lead (Pb) on the mortality and uptake potential of catfish (Clarias gariepinus) was investigated. Four test groups A, B, C and D were created with varying concentrations of Pb. Group A served as the control while the others were polluted with Pb at different increasing concentrations, B (1ppm), C (5ppm) and D (10ppm). Four aquariums were designed to accommodate these fishes labelled A, B, C and D of varying concentrations. The initial and final concentrations of the fishes were determined using Atomic Absorption Spectroscopy (AAS) and the results obtained revealed that the variation in the concentration of lead in the fish within the duration of the experiment. Concentration values obtained include, A(9.98±6.67)mg/kg, B(10.02±3.65)mg/kg, C(18.88±5.46)mg/kg and D(14.97±8.07)mg/kg. The maximum permissible limit for the concentration of Pb in fishes set by FAO and WHO are 2 and 0.5mg/kg respectively which were exceeded.

Comparison of result of control against other groups using one way analysis of variance (ANOVA) where the results are expressed as p-value showed that group B was considered non-significant i.e p>0.05 while A, C and D were significant i.e p<0.05. Survival of aquatic life is dependent on the degree of toxicity leading to bioaccumulation and eventually resulting in death of an organism. In order to reduce the effect of heavy metal toxicity, a regulatory body should be set up to tackle the issue of industrial effluents spilling into water body as this is known to be one of the major factors that increases the level of heavy metals in the aquatic body.