Authors: Dedeke, G.A. and O.R. Omotoso
Research Journal of Agriculture and Biological Sciences, 4(3): 251-256, 2008
Abstract:
The Orelope stream, Ago-Iwoye was investigated for the impact of non-point pollutants on its physicochemistry. The biochemical oxygen demand (BOD) and chemical oxygen demand (COD) at all sampling sites were higher than permissible levels allowed by the Federal Environmental Protection Agency (FEPA) and Ogun State Environmental Protection Agency (OGEPA) for freshwater.
The BOD (256mg/L) and COD (667mg/L) obtained at the sampling site C (dumping site) showed the highest severity. The dissolved oxygen (DO) of the stream was low at all sampling sites, the highest severity correlates with sampling site C (the dumping site). The concentration of Lead (Pb) at all sampling sites was higher than the permissible level for freshwater , the value of 0.05 ± 3.00 obtained at sampling site C was the highest. Barium was recorded only at sampling site A, which coincides with the abandoned fish pond and its value was higher than the WHO[13] standard. Lead contributed more significantly (p<0.05) to the heavy metal concentration of the stream and is highly positively correlated with alkalinity (0.98), pH (0.88), total dissolved solids (0.90) and hardness (0.68) of the stream (p<0.05). The means of acidity, alkalinity, conductivity, pH, chloride, chromium, copper, cadmium, lead, magnesium, total dissolved solid, nitrate, nitrite, phosphate and sulphate were significantly different at all sampling sites (p<0.05) with sampling site C recording the highest means of all these parameters. Visual appraisal of the stream revealed that eutrophication and ecological succession is gradually taken place, thereby decreasing the volume of the stream especially at the location of the dumping site (sampling site C)