LEAD AND CADMIUM UPTAKE BY AFRICAN CATFISH (Clarias gariepinus) HEALTH RISK ASSESSMENT

ABSTRACT

This research was designed to assess the potential uptake  of two heavy metals (lead and cadmium) by juvenile African catfish “Clarias gariepinus’’ in a simulated environmental conditions. A total of 24 fish samples were separated into four test groups A, B, C, and D with nominal concentrations of 1 ppm (A), 5 ppm (B), 10 ppm (C) of lead and cadmium while control (D) contained no heavy metal. Samples were exposed for a total of seven (7) days and duplicate experiments were carried out. The heavy metal concentrations in the fish samples were determined using Atomic absorption spectrophotometer. Results obtained indicated a concentration range for Pb from 0.2 to 11.3 mg/kg with mean values of 0.40 to 8.28 mg/kg. While cadmium concentration values ranged from 3.20 to 28.0 mg/kg with mean values of 5.23 to 21.7 mg/kg. The control group did not reveal any significant uptake in the fish samples. comparison of the concentrations obtained with set regulatory standards found that the obtained concentrations of Pb and Cd exceeded the permissible limit (0.30 and 0.05 mg/kg) of fish set by EPA/WHO respectively. The results obtained also showed p-value at significance level at 0.05 of the different test groups. The concentration of cadmium were generally found to be higher than lead in the fish samples. The concentrations of the metals obtained for each group set well below permissible limit for BCF/HQ of (≤ 1) indicating low toxicity level to potential consumers of the fish. Results from the study also indicate that exposure of these metals to fishes even at low concentration could potentially pose public health hazard.