Toxic Metal Concentrations and Exposure Risks Associated with Surface Water, Seafood (Clarias gariepinus, Oreochromis niloticus, Cottus gobio) and Vegetable (Telfairia occidentalis) from Elebele River, Nigeria

Abstract

Human exposure to elevated levels of environmental contaminants is an important concern of health toxicology. This study assessed the toxicity level of toxic metals including Arsenic (As), Cadmium (Cd), Chromium (Cr), Copper (Cu), Lead (Pb) and Nickel (Ni) in samples of water, seafood (Clarias gariepinus, Oreochromis niloticus, Cottus gobio) and vegetable (Telfairia occidentalis) from the adjacent area of Elebele River, Nigeria, bioconcentration and toxic metal exposure posed to communities consuming these foodstuffs. The following indices: single-factor index and the comprehensive pollution index, metal pollution index, estimated daily and weekly intakes, hazard index and lifetime cancer risk were applied. Samples of water, seafood and vegetable were analysed using Atomic Absorption Spectrophotometer. The results showed that the concentrations of metals except for Cd in water samples were higher than the permissible limits by international organisations. Results also revealed that the concentrations of metals in foodstuff samples were within limits. Furthermore, the values of estimated weekly intakes calculated were lower than the limits of provisional tolerable weekly intakes established by the Food and Agriculture Organization and World Health Organization. This suggests no health risks and is consistent with the HI results. However, As was a major contributor (96.9%) to health risks associated with the ingestion of water. Lifelong consumption of T. occidentalis might be hazardous in the study locality. The carcinogenic risk was > 1 × 10‒4 for As and Ni. Therefore, to reduce the health risk and the extent of metal contamination, steps must be taken for the efficient removal of metals from the water body.