Geophysical and hydro-chemical investigation of contamination plume in a basement complex formation around Sunmoye dumpsite in Ikire, Southwestern Nigeria

• Published in: Modeling earth systems and environment 2018-06, Vol.4 (2), p.753-764
• Main Authors: Akinola, Bisola S., Awoyemi, Musa O., Matthew, Olaniran J., Adebayo, Adebiyi S.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Aquifers; Basement rock; Chemical analysis; Chemistry and Earth Sciences; Complex formation; Computer Science; Contamination; Dug wells; Dump leaching; Earth and Environmental Science; Earth Sciences; Earth System Sciences; Ecosystems; Electrical resistivity; Environment; Fractures; Geoelectricity; Geophysical surveys; Geophysics; Groundwater; Groundwater pollution; Leachates; Lead; Math. Appl. in Environmental Science; Mathematical Applications in the Physical Sciences; Original Article; Physics; Pollution; Profiling; Soil; Soil contamination; Soil investigations; Soil pollution; Sounding; Statistics for Engineering; Surveying; Topsoil; Two dimensional analysis; Water analysis; Water pollution; Water sampling
• ISSN: 2363-6203; 2363-6211
• DOI: 10.1007/s40808-018-0455-8

Integrated geophysical survey involving Schlumberger Vertical Electrical Sounding (VES), 2D horizontal profiling and hydro-chemical analysis have been used to map pollution plume around Sunmoye dumpsite located in the basement complex of Ikire, Southwestern Nigeria. This was with a view to assessing possible groundwater pollution arising from leachate plume emanating from the dumpsite. Seventeen (17) vertical electrical sounding (VES) and Nine (9) Wenner profiling were carried out. The 2D data obtained were processed and inverted using RES2DINV inversion software. Ten (10) water samples were collected from hand dug wells for physical and chemical analysis. The geoelectric sections and the inverted 2-D resistivity structures delineate three subsurface geological units consisting of the topsoil, weathered layer and the fractured/fresh basement rock. The weathered layer constitutes the main aquifer unit. The 2-D resistivity structures show that within the premises of the dumpsite, the topsoil and the weathered basement aquifer unit are characterized by relatively low layer resistivity values of  10 mg/l and lead concentration > 0.01 mg/l which confirm groundwater pollution. It can be concluded that the soils and the groundwater in the areas around the investigated dumpsite have been polluted. The polluted zone has a depth extent of about 2.5–7.5 m.