The concentrations of inorganic and organic substances (biochemical oxygen demand, chemical oxygen demand), cations (Pb2+, Fe 2+, Cu2+, Mn2+), anions (NO3-, PO43-) and physical analysis (Total suspended solids, oil and grease and pH), were determined in storm water runoff collected from selected areas in Ilorin metropolis. The samples were taken between April to July 2004 and the analysis was done using Hellige comparator and ultra violet-visible spectrophotometer. Regression analysis model was carried out on each concentration of storm water runoff loads in relation to vehicle; some of the variables such as chemical oxygen demand, iron, manganese, oil and grease showed dependence on vehicular counts. The others including nitrate, pH, total suspended solid, lead, phosphate and biochemical oxygen demand were not dependent on vehicular counts.
Keywords: Ilorin Metropolis, Regression Models, Storm Water
