Impact Evaluation of Urbanization on River Ona in Eleyele Catchment, Ibadan, Nigeria

Abstract

The study investigated a long-term effect of urbanization on the water quality of Ona River in Eleyele Catchment Oyo State Southwest Nigeria Secondary water quality data between 1979 and 2007 were collected from Eleyele s Water Works Ibadan In compliment water samples were collected from five sampling points along River Ona Important water parameters analyzed using standard procedures were temperature pH electrical conductivity EC total dissolved solids TDS turbidity total alkalinity total hardness metals calcium magnesium sodium copper lead cadmium chromium nickel iron and anions nitrate sulphate chloride Results showed increased concentration of nitrate and chloride and decreased dissolved oxygen level of River Ona over 28-year assessments Present field study showed relatively high values of Pb 0 06-1 15 mg L Cr 0 01-1 31 mg L Cd 0 00-0 26 mg L Fe 0 40-1 96 mg L Ni 0 02- 0 27 mg L and nitrate 27 0-50 0 mg L compared with World Health Organization WHO permissible standards in drinking water Water quality parameters were generally high between sampling point 1 and 3 due to the influx of industrial effluent from the nearby industries and indiscriminate disposal of wastes at the bank of the river