Hydrochemistry of Groundwater in Umuahia South Local Government Area, Abia State, Nigeria

Twenty-seven boreholes in Umuahia South Local Government Area were studied using standard field and laboratory techniques of water resource investigation to assess the quality status of groundwater in the area. This was done to appraise the suitability of the water for domestic uses. Na+ and Ca++ dominate the cations with average values of 11.6mg/l and 5.22mg/l respectively, while HCO3- and Cl- dominate the anions and show respective mean values of 55.6mg/l and 15.6 mg/l. The low Cl- concentration shows that the salt water contamination in the adjacent coastal aquifers of the Niger Delta has not reached Umuahia, which is more hinterland. The water is low in dissolved constituents. However, the acidic status of the water (pH values from 4.39 to 6.56) calls for treatment. Treatment is also needed for iron in boreholes with concentration more than 0.3 mg/l. These treatments would make the water potable for drinking and other domestic purposes with respect to the parameters analysed. The major source of the ions in the water includes mineral assemblage in the rocks, geochemical processes operating within the groundwater system, as well as atmospheric precipitation. Exploitation of water from different depths, local geochemical processes in the aquifer, as well as concentration of elements in boreholes located in areas of low hydraulic heads are some of the reasons for haphazard variations in the geochemical parameters from one borehole to another.