Hydrogeochemical Assessment of Mbanabor Area, Anambra Basin, Southeastern Nigeria

Surface and groundwater resources evaluation of Mbanabor was done to assess the quality for human consumption and agricultural purposes. This was achieved through physicochemical and bacteriological analysis of twenty one (21) water samples from both surface and groundwater sources in the area. The result reveals that the concentration of Ca2+(mg/l), Mg2+(mg/l), Na+(mg/l), K+(mg/l), Fe2+(mg/l), Pb2+(mg/l), Cd2+(mg/l), Zn2+(mg/l), and Cu+(mg/l), range between: 0.12 – 27.21, 0.05 – 3, 3.23 – 7.06, 0.1 – 7.31, 0.05 – 3.62, 0.002 – 0.28, 0 – 0.02, 0.04 – 2.5 and 0.001 – 3.0 respectively. The range of SO42- (mg/l), NO3- (mg/l), and HCO3- (mg/l), are between: 1.0 – 13.1, 0.27 – 49.0 and 8.00 – 20.5 respectively. The average of pH (mg/l), colour (Hz), temperature (0C), conductivity (us/cm), turbidity (NTU), TDS (mg/l), TSS (mg/l), BOD (mg/l), DO (mg/l) and hardness (mg/l), are: 6.19, 61.43, 24.7, 63.57, 4.48, 21.44, 5.05, 0.69, 4.64 and 6.4 respectively. Classification of the water samples shows the predominance of Ca(Mg)Cl(SO4) and Na(K)Cl(SO4) water types that are largely soft. The values of the Sodium Adsorption Ratio (SAR) range between 0.24 – 2.86 indicating prevalence of good water for agricultural uses. The surface water sources are predominantly infected with microbial contamination, indicating significant input of organic (Faecal) wastes in the flow system. Water resources development programmes in the area requires elaborate qualitative assessment, to ensure that any necessary pre-use treatment is effected. Keywords: Water Quality, Water Classification, Hydrogeochemistry, Sodium Adsorption Ratio

Determination of The Hydraulic Conductivity, Transmissivity And The Environment of Deposition of Owelli Sandstone, in Anambra Basin, Southeastern Nigeria, Using Grain Size Distribution Analysis

This study estimated hydraulic conductivity, transmissivity, and interpreted the environment of deposition of the Owelli Sandstone in Mbanabor area of Anambra Basin, Southeastern Nigeria. These were achieved using grain size distribution analysis, and borehole lithological logs. The results indicated that values of hydraulic conductivity (m/s) and transmissivity (m2/s) range between 2.89 x 10-2 – 1.52 x 10-1, and 4.8 x 10-1 - 5.3 x10-1, respectively, indicating prevalence of aquifer of good performance. The aquifer units are predominantly unconfined, with variable thicknesses and depth of occurrence. The values of the mean, sorting, skewness and kurtosis, from sieve data range between 0.2 - 0.9Φ, 0.49 - 1.97Φ, -0.05 - 0.21Φ and 0.96 - 1.52Φ respectively. Multivariate discriminate functions revealed that Owelli Sandstone may have been deposited dominantly by beach process, in shallow agitated marine, and shallow marine environment. Key words: Hydraulic Conductivity, Transmissivity, Owelli Sandstone, Anambra Basin, Depositional Environment