Direct current (DC) geoelectrical resistivity measurements have been conducted to investigate
groundwater contamination at a non-engineered, open dumpsite facility in Lagos, southwestern Nigeria. The inferred lithologies from the tomographic imaging include topsoil, sandy-clay and sandy units; the delineated low resistive top layer has resistivity values ranging from 0.64-7.5 m typical of leachates and localized within sandy-clay unit extending to depths of 42-52 metres. The groundwaters from the shallow aquifer units are observed to be hazardously contaminated in area where household,
market and industrial wastes are known to be disposed improperly. Thus, deeper aquifer units beyond
the contaminated layers should be drilled with screened borehole in order to avert immediate groundwater pollution. This study has further demonstrated the efficacy of using surface geophysical techniques to map contaminant plume in dumpsites and determine the extent of groundwater contamination
