Abstract

The present study investigates possible contamination of untreated and treated groundwater by lead, faecal coliform and Escherichia coli in a hundred randomly selected boreholes from different parts of Ibadan metropolis, located in South West Nigeria. Total lead contents in the water samples were measured by atomic absorption spectrophotometer while coliform count was undertaken using the multiple tube fermentation technique. Detection of E. coli in the water was by the presumptive and confirmative tests. Data obtained showed that all the untreated water samples contained lead concentrations in the range of 1.0 - 12.0 ppb, with a mean value (X) of 4.9 ± 0.18 ppb. Seventy-three percent of the  borehole water samples had coliform, with 18% of these borehole samples having detectable E. coli. All the sachet “water” samples that were supposedly treated having lead concentrations that were in the range of 2.0 - 9.0 ppb with one of them having coliform bacteria. The results obtained supported previous findings that severe environmental degradation, which is readily observable in most parts of Ibadan City, could possibly contribute to pollution of ground water source like boreholes. Supply of adequately treated water from public waterworks to the teeming population in Ibadan City is an important problem that must be solved by the government.

Key words:  Groundwater, sachet water, Ibadan, lead, coliform, environmental pollution.