Investigating the near surface leachate movement in an open dumpsite using surficial ERT method

Abstract

Geoelectrical resistivity imaging technique was conducted at Abule-egba open dumpsite, Lagos with intentions to monitor the movement of the contaminant leachate within the near surface. The two survey traverses (T1 and T2) of 2D electrical resistivity tomography were conducted using Wenner array configuration with minimum electrode spacing of 1 metre and maximum data levels of seven. The inversion models revealed the two delineated geoelectrical layers which are sandy-clay and sand units. The leachate fluids has the resistivity values of 5.75 – 10.4 Ωm at depth range of 2.5 – 4.0 metres along T1 and T2 moving from NW to the SE section. The leachate fluids are capable of polluting shallow groundwater aquifer within the study area and the residents are advised to drill deeper in the subsurface for clean and portable groundwater resources. Keywords: Environmental Geophysics, Leachates, Near-surface geophysics, Open dumpsite, Electrical resistivity tomography (ERT