Abstract

Results from chemical analyses of forty dug well water samples in the Effurun-Warri metropolis show that mean pH is 7.1 and mean TDS is 193 mg/l. Representative mean levels of cation occurrence include Ca, Mg, Na and K at 6.13mg/l, 4.09 mg/l, 4.89 mg/l and 3.37 mg/l respectively. Mean anion concentration for bicarbonate was 8.20mg/l, 1.27mg/l for sulphate and 23.74mg/l for chloride. Physical and chemical parameters are thus well below WHO and Standard Organization of Nigeria drinking-water quality standards. Piper diagram plots of the data indicate that ground water is predominantly Ca+Mg+Na Chloride facie and that mixing and ion exchange processes control the dominant cation in space and thus at each specific locality. Leachates from the many, widely distributed and unregulated landfills and dumpsites have been identified as possibly the principal sources of major ion loading to groundwater. The ubiquitous onsite sewage treatment soak away pits also contribute major ions to groundwater. These two sources are thus accountable for any observed local spikes in groundwater chloride content rather than sea water intrusion as had been previously suggested.

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