ABSTRACT
This study determined the concentration of heavy metals in selected commercially important fish species (Oreochromis niloticus, Heterotis niloticus and Synodontis granulosus) from River Asse in Delta State, Nigeria. The research objectives were to determine the concentration of heavy metals (Cadmium, Copper, Zinc, and Lead) in O. niloticus, H. niloticus, and S. granulosus, target hazard quotient (THQ) and total target hazard quotient (TTHQ), estimated annual intake (EAI), estimated daily intake (EDI) and the total toxicity of mixtures (TTM) index for these heavy metals in O. niloticus, H. niloticus, and S. granulosus. Method of analysis of heavy metals was done using Atomic Absorption Spectrophotometer. The study revealed that concentrations of Cd, Zn and Pb in O. niloticus, H. niloticus and S. granulosus surpassed established International thresholds for these metals in fish indicating the unfitness of such fish for prolonged consumption by man while Cu was within the acceptable range. The THQ and TTHQ values were found to be higher than acceptable levels in Pb, indicating potential health risks. The estimated daily intake (EDI) and estimated annual intake (EAI) of heavy metals by potential consumers were highest in Zn and exceeded the recommended limits, and the total toxicity of mixture (TTM was found to be highest in O. niloticus. These findings suggest that the consumption of O. niloticus, H. niloticus and S. granulosus from the river Asse may pose health risks due to heavy metal contamination, emphasizing the need for public awareness and education about the sources and health effects of heavy metal contamination. Further studies are recommended to investigate heavy metals contamination levels in invertebrates and other fish species of nutritional and economic importance, incorporate additional heavy metals in research, establish the relationship between heavy metal contamination and physiochemical parameter.
