The comparative assessment of industrial and agricultural effluents on surface water qualities of Ona
Stream at Oluyole industrial Estate was carried out. This was to identify major pollutants, their effects on water
qualities and to ascertain the potential of using the polluted surface water for irrigation purposes. Some parameters
which gave evidence of pollution due to industrial effluent discharge were Temperature 28-320
C, Dissolved Oxygen
(DO) of 3.0 – 5.5 mg O2/l, Chemical Oxygen Demand (COD) of 64-255 mg O2/l, Biochemical Oxygen Demand
(BOD) of 26-70 mg/l. Others were Total Suspended Solids (TSS) 28-36 mg/l, Total Dissolved Solids (TDS), 1285-
2090mg/l, Oil and grease 6.8-3.4 mg/l. The parameters from agricultural effluents were Temperature 28-300
C, DO,
1.62-5.10mg O2/l, BOD, 26-480 mg/l, COD, 64-1750 mg O2/l, TDS, 1285-2250 mg/l and TSS, 28-53 mg/l. All these
values are above the Federal Environmental Protection Agency (FEPA) maximum allowable limit for effluent
discharge into surface water. The statistical analyses carried out showed significant differences in all the
physiochemical and heavy metal parameters analyzed at 5% significance level. Usage of Ona stream for irrigation
purposes was not encouraged due to the health hazards it poses for both the crops and crops consumers. The
presence of faecal coliform contamination, physiochemical and heavy metal pollution in large quantities confirmed
this. Development of clean water technology for water pollution control, mathematical models for predicting
pollution levels and application of appropriate polices to compel industries to treat effluent before discharging into
the stream are some of the recommended solutions. [New York Science Journal 2010;3(7):25-33]. (ISSN: 1554-
0200).