Assessment of Selected Heavy Metal Concentrations in Water and Sediment around Ikirun Iron-Smelting Industry, Ikirun, Osun State, Nigeria

This study was carried out on a stream, three ponds, and two wells located within the vicinity of the Iron-smelting industry in Ikirun, Ifelodun Local Government Area of Osun State. Water samples were collected from seven sampling points along the stream, two hand-dug wells, and three ponds. A total of 72 water samples were taken at two-month interval between January and November. Sediments’ samples (60) were also collected from the same locations where water was sampled, except for the hand dug wells. Heavy metals (Fe, Zn, As, Pb, and Cd) were analysed using Atomic Absorption Spectrophotometry. Cadmium (0.01 ± 0.00 mg/l), Pb (0.01 ± 0.00 mg/l), and As (0.01 ± 0.00 mg/l) had concentrations above both World Health Organization (WHO) and Nigerian Industrial Standards (NIS) limits in both the surface and underground waters while Zn (0.13 ± 0.03) and Fe (0.18 ± 0.00 mg/l) had concentrations below the maximum permissible limits of WHO and NIS in both surface and underground water samples. Pb (0.01 ± 0.00), Zn (0.12 ± 0.00), and As (0.01 ± 0.00 mg/l) were observed to be lower in water than their corresponding values in sediment (0.05 ± 0.00, 0.23 ± 0.00, and 0.04 ± 0.00 mg/kg) respectively. The study concluded that the water bodies around the iron-smelting industry have high heavy metal contents above the regulatory standards and the water could not be recommended for drinking purpose