Heavy metal contamination and associated ecological risk on farms around Oluyole industrial area, Ibadan

Abstract

Assessment of heavy metal concentration was done to determine the contamination on various farms around Oluyole industrial area and the corresponding ecological risk they posed in the area. Four farmlands were visited and different plant samples ((Musa acuminata (banana), Saccharum officinarum (sugarcane), Abelmoschus esculentus(okra)and Zea mays (maize)) were collected on each farmland. The plant samples were analysed using Atomic Absorption Spectrometer (AAS) and the data collected were used to analyse the bioaccumulation factor, contamination factor, and ecological risk indices. The metal concentrations result indicates that the significant difference in the heavy metals from each other is at 5% level of significant also the mean separation showing the sequence Cr>Pb>Co>Zn>Cd>Mo>Mn values. Bioaccumulation factor analysis showed that cobalt (5.55) is the heavy metal accumulated the most by the Musa acuminate plants while chromium (0.74) is the metal accumulated the most by the Saccharum officinarum plants. Chromium (1.10) is also the most accumulated by the Abelmoschus esculentus plants while lead and zinc (1.39 and 3.61 respectively) are the heavy metals accumulated the most by the Zea mays plants. The calculated contamination factor showed that Co, Mn, Cr and Cd are the metals showing very high contamination of the plants (CF≥6) while Pb (1.10) showed moderate contamination of the plants. The ecological risk assessment showed that only Cd has very high ecological risk within the four farmlands while the whole industrial area is at a high ecological risk (2094.42) for pollution. Consequently, due to the effects of these heavy metals to the consumers, the farmlands need to be relocated farther from these industrial environments and an environment impact assessment need to be carried out to create awareness to the habitants of this area on the impact of these industrial activities to their environments.