چکیده (انگلیسی):

The concentrations of four heavy metals [Lead (Pb), Aluminium (Al), Nickel (Ni) and Chromium (Cr)] in Synodontis clarias sampled in July, August and September (2014) at two locations along the Benin River, Delta State, were investigated by means of the atomic absorption spectrophotometer technique. A total of 24 samples of S. clarias with an average weight of 189g and length of 23cm were collected from the two locations along the river. Results showed that the total mean concentration values of metals recorded in S. clarias was: Pb (1.507mg/kg), Al (5.170mg/kg), Ni (2.380mg/kg) and Cr (0.075mg/kg). ANOVA showed significant differences (p<0.05) between the concentrations of each metal in S. clarias of Benin River at Koko during the different months of sampling. However, the concentration of Pb was not significantly different (p>0.05) in July compared to September, and July compared to August. Metal concentrations in the fish were generally within the acceptable limits set by Food and Agriculture Organisation (FAO) and World Health Organisation (WHO) in fish and fishery products, except for Nickel which exceeded the FAO recommended 0.5-0.6mg/kg limit. However, the concentrations of the heavy metals in water were much higher than recommended safe limits for human consumption thereby posing a direct health challenge to the people of the Koko community who depend on the water for domestic uses. There is an urgent need to check the sources of pollution in the area to forestall any imminent danger.