Comparative Analysis of the Quality of the Shallow and Deep Aquifer Waters of Nsukka SE, Nigeria – A Preliminary Approach to Water Resource Development

Abstract

Comparative analysis of the shallow and deep aquifers of Nsukka SE, Nigeria was studied as a preliminary approach for the underground  water resource development of the region.  Method of approach involves the identification of rock formations and delineation of their stratigraphic  relationships. Activities involved collection and analysis of water samples from boreholes and hand dug wells. A total of 14  water samples were collected (7 from shallow and deep aquifer each) and analyzed  for inorganic and organic components. Ca^2+, Na⁺, Mn²⁺, Cl^-, Pb and Cd were analyzed  using Atomic absorption spectroscopy. K⁺ was determined using flame photometer method. Copper Cu²⁺ was analyzed  using spectrophotometer, pH  was analyzed with the aid of pH  meter, Fe²⁺ was  determined calorimetrically using Spekker absorption meter; Tds was determined using glass fiber filter. Turbimetric method was used to assess turbidity. Anions like HCO₃^- were also estimated by titrimetric  method. Coliform analysis was carried out by the most probable number technique (MPN).

The result shows that average pH  for deep and shallow aquifer gives 5.8 and 6.3, sulphate 14.2 and 10.97, Nitrate 2.5 and 2.2., Phosphate 1.48 and 1.68, iron 1.98 and 1.60 magnesium 11.4 and 11.8, Sodium 1.80 and 2.4, Chloride 8.4 and  9, Tds 33.51 and 62.17. The coliform count ranges from 3/100 to 7/100 ml only for shallow aquifer (pollution), magnesium is the major  contributors of hardness in both cases.  Deep aquifer water plots as magnesium cation and a no dominant anion and on the transition between fresh and salt water (brackish water). The shallow aquifer has magnesium sulphate and plots in the zone of sea water, and shows hard water. The SAR for deep aquifer is 0.58, while that of shallow aquifer is 0.32 both are excellent for irrigation. Both waters are ideal for use in industries and homes, while the aquifers are highly polluted by iron, the shallow aquifer is polluted by water  borne diseases. Reference to these information is ideal for the water resource development of the region.

Keywords: Aquifers, Comparison, water quality, Nsukka SE, Anambra basin  SE Nigeria