Hydrochemical Appraisal of Isebo River in Ibadan South-Western Part of Nigeria

Abstract

Aims: To investigate the hydrochemical regime of Isebo River in Ibadan, South-western Nigeria with respect to its chemical quality status for drinking purposes due to its proximity to an industrial area and to also give recommendations based on the findings. Methodology: Ten water samples were collected from the river while five raw effluent samples were also collected from the discharge points of the polluting industries in order to assess their chemical composition and toxicity levels in the laboratory. Concentrations of heavy metals, such as, Iron (Fe), Copper (Cu), Zinc (Zn), Chromium (Cr), Cadmium (Cd), Nickel (Ni) and Lead (Pb) were determined using Inductively Coupled Plasma (ICP) and Optical Electro-Spectrometer (OES) analytical procedures respectively. Physico-chemical parameters such as Electrical Conductivity (EC), Total Dissolved Solids (TDS), Temperature (T), the acidity and basicity levels (pH) of both the effluent and water samples were determined in the field using a Symphony SP80PC portable instrument. Results: The output of the chemical analyses revealed mean concentrations in the order of abundance of toxic heavy metals in effluent samples as Fe>Zn>Cu>Cr>Ni>Pb>Cd while that of water sample analysis data is given as Fe>Zn>Cu>Ni>Cr>Pb>Cd. The coefficient of determination R2= 0.9784 and 0.9809 of EC and TDS obtained for effluent and water samples respectively, shows a good positive correlation coefficient between the two parameters while temperature and pH varied anomalously. Conclusion: The mean values of heavy metals in effluent and water samples are generally higher than the background values and the threshold of permissible contaminant levels established by the World Health Organization (WHO) respectively and this could lead to serious health hazards. Therefore, it is recommended that environmental monitoring and state-of-the-art effluent treatment facilities should be put in place by the polluting industries to prevent further pollution of the river and vulnerability of man to potential health hazards.