2-D ELECTRICAL RESISTIVITY INVESTIGATION OF SOLID WASTE DUMPSITE AT GONIN-GORA, KADUNA STATE, NIGERIA
2-D ELECTRICAL RESISTIVITY INVESTIGATION OF SOLID WASTE DUMPSITE AT GONIN-GORA, KADUNA STATE, NIGERIA
No Thumbnail Available
Date
2014-05
Authors
MIKE, ASUERIMEN
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Leachate effluence from refuse dumpsite is an important source of soil and groundwater pollution. Consequently, assessing the impact of Leachate is an active area of soil and groundwater research. 2-D Electrical Resistivity imaging survey was carried out at a dumpsite in Gonin-Gora area of Kaduna State, with the aim of determining how accurately electrical measurements could delineate the influx of leachate into soil and groundwater. A modern and state-of-the-art field instrument, the ABEM Automatic LUND Imaging System (Terrameter SAS 1000 and ES 464), produced by ABEM instrument AB, wasused to accomplish this task. This uses multi-core cables with takeouts at 2m intervals, having a total of 42 electrodes covering a spread of 200m. Six profiles were covered and the data were processed to display the variations of electrical resistivities using the RES2DINV software. Four of the profiles were inside the dumpsite while two profiles were outside the dumpsite.Also, one Vertical Electrical Sounding (VES) was conducted inside the dumpsite with thesame ABEM TerrameterSAS 1000,and was interpreted using computer software (IPI2win) which gives an automatic interpretation of the apparent resistivity data.The results of this survey in correlation with a Borehole log of the area revealed three layers: The topsoil, which consists ofreddish brown lateritic and sandy clay, has resistivity values between 8Ωm and 850Ωm and its thicknessvaries between 0.01 m to 7.00 m. The second layer is the weathered basement, and has resistivity values between 150Ωm and 940Ωm. Its thickness ranges between 2.00 m to 16.00 m. The resistivity of the fresh crystalline basement which forms the third layer ranges between 820Ωm to 4000Ωm. The 2D Inversion delineated contamination plumes as low resistivity zones with resistivity values ranging between 1Ωm and 27Ωm, from the ground surface to
vii
varying depths of 0-3 m in profile 1 and profile 4, believed to be leachate derived from decomposed waste of higher concentrations, while profile 2,profile 3 and profile 6 delineated contamination plumes withresistivity zones ranging between 100Ωm to 200Ωm, from the ground surface to varying depths, believed to be leachate from decomposed wasteof lower concentrations.There was no evidence of topsoil or groundwater contamination as revealed by the inversion model in profile 5.The VES data revealed that the area has a shallow aquifer of about 4m, indicating that the topsoil as shown in all the profiles except profile 5, and the groundwater in profiles 3 and profile 6 are contaminated.A comparison ofthe measured apparent resistivity pseudosection and the calculated apparent resistivitypseudosection resulted in a reasonably good agreement with the inverse model resistivity section.
The study area has a shallow depth to Basement of 1.30m and a depth to water table of about 4m.The inverse model revealed weak zones which could be interpreted as fractures, which aid in the migration of the leachate as shown in profile 3 and profile 6.
Description
Keywords
2-D ELECTRICAL RESISTIVITY INVESTIGATION OF SOLID, GEOPHYSICS