Abstract

Several African communities obtain their domestic water supplies from dug wells and this study takes Ibogun, Pakoto and Ifo communities in Ogun State, Nigeria as being typical. The objective is to assess the quality of the water supply from these dug wells, ascertain the contamination problems that may confront the consumers, and provide appropriate remedies. Twenty  dug wells were randomly selected in each community. Water samples from the selected dug wells were collected during July - August 2009. The samples were checked for odour, colour and taste; and through standard methods, they were analyzed for pH, total solids, total hardness, chlorides, sulphate, nitrates, magnesium, calcium, manganese, sodium, copper, zinc, iron and lead; total viable count, total coliform count, faecal coliform count and faecal streptococci count. Most of the pH values of the samples were outside the recommended range of 6.5 – 8.5 for drinking water. Predominantly, the ionic dominance pattern observed were Na > Ca > Mg and HCO₃ > Cl > SO₄, indicating typical cationic characteristics and anionic characteristics of groundwater. For total solids and total hardness, guideline values were largely met. Levels of iron did not exceed the WHO guideline value of 0.2 mg/l for Fe in drinking water. Mean levels of Mn measured were far in excess of the average of 0.01 mg/l for fresh water, while in relation to the WHO guideline value of 0.4 mg/l for Mn in drinking water, the levels measured were low. Generally, the levels of nitrates, sulphate, chlorides, magnesium, manganese and iron were moderately high, but the WHO guidelines were not exceeded. The WHO guidelines for microbiological quality of water were met in several cases. Matching of non-technical and techno-social remedial measures is recommended. These include sensitization of the populace on merits of qualitative domestic hygiene and environmental protection practices such as cleaner compounds and strict enforcement of environmental protection laws.

Key words: Dug wells, water, physico-chemical analyses, microbial analyses.