Vertical electrical soundings (VES) method using the Schlumberger array was used in the study area. 20 VES were probed and the data interpretation was carried out with aid of computer softwares IPI2Win and surfer 8. The results revealed three subsurface geoelectric layers (top soil, weathered layer and fresh layer) at VES 4, 5, 6, 7, 8, 9and 10, and the rest VES stations have four subsurface geoelectric layers (top soil, lateritic clay, weathered layer and fracture/fresh layer). The top layer resistivity values range from 112-829 ohm-m, and thicknesses from 0.5-8.85m. VES 1, 2, 3, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 with four layers, the second layer constitute the Lateritic clay and its resistivity values range from 34.9-406Ωm, and thicknesses from1.37-5.78m respectively. The second layer of VES 4, 5, 6, 7, 8, 9 and 10, and the third layer of VES 1, 2, 3, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20 which constitute the Weathered zone has resistivity values that range from 8.99-339Ωm and thicknesses between 3.01-41.6m. The fourth layer of VES 11, 12, 17, 18 and 19 constitute the Fractured basement with resistivity values that range from 182-547Ωm. The third layer of VES 4, 5, 6, 7, 8, 9 and 10, and the fourth layer of VES 1, 2, 3, 13, 14, 15, 16 and 20 constitute the Fresh basement with resistivity values that range from 2090-19465Ωm. It was also observed that the Total Dissolved Salt values range from 12.797-778.643mg/l. VES has shown that it's very reliable for the determination of lithology and groundwater quality in the study area.
This study was carried out with the aim of demonstrating the application of vertical electrical sounding (VES) method of investigation in the exploration for groundwater in University of Abuja, Permanent Site and Environs. A total of 12 VES points were probed in the area with AB/2 of 1 – 250m and covering a total area of 6.75km2. ABEM SAS 300c tarrameter was used to generate the data using schlumberger array method. The data was interpreted using computer iteration methods (IPI2Win). Isoresistivity of topsoil, isoresistivity of weathered layer, isoresistivity of basement, weathered layer thickness and a 3-D of weathered layer thickness were also generated using surfer software. The result reveals five curve types (A, H, HA, HK and QH) and it shows variation in the layers available in the study area, some with four geo – electric layers: top soil, lateritic clay, weathered basement and fractured/fresh basement while some with three geo-electric layer: topsoil, weathered and fractured/fresh basements. It also shows variation in the groundwater potentiality of the study area i.e. good (VES 1, 5, 7, 9), moderate (VES 2, 4, 6, 8, 11, 12) and low (VES 3, 10). The good potential area is suggested for drilling of boreholes.
The effect of degradation caused by ion leachate migration in the soil of Gosa dumpsite was investigated with reference to water and soil from dumpsite located at Idu Industrial area- Abuja. This was done to determine the health and environmental pollution status caused by heavy metals concentration present in the dumpsite and its effect to inhabitants within the settlement. Soil samples collected during dry and wet season were pretreated and digested using hotplate. The heavy metal concentrations were determined using Atomic Absorption Spectrophotometer. The samples were analyzed for concentration of lead (Pb), cupper (Cu), manganese (Mn), nickel (Ni) and chromium (Cr). Control soil samples were taken 300m away from the dumpsite. The dumpsite was divided into four cardinal points including the centre from which samples were collected for analysis. Water samples were collected from three wells to test for physiochemical properties of PH, chemical oxygen demand (COD), biochemical oxygen demand (BOD), dissolved oxygen (DO), Hardness, Conductivity and Alkalinity. The result showed significant difference in concentration of these metals in the dumpsite and control. The dumpsite was found to contain significant amount of toxic heavy metals. The analytical results indicates that in both dry and wet season, most of the metals concentration were above the World Health Organization (WHO) and Standard Organization of Nigeria (SON) standards, which is a major concern as these metals pose threats to human life, agricultural productivity and unsafe for the inhabitants.