An integrated geophysical investigation involving 2D-Wenner profiling, very low frequency\r\nelectromagnetic, vertical electrical sounding (VES) and water quality analysis was conducted around\r\nAule area within Akure the capital city of Ondo state southwestern Nigeria where there have been\r\nreported cases of groundwater contamination. Also hydrochemical analysis was carried out on five\r\nwater samples in the area; two from boreholes and others from hand dug wells. Results of the\r\ninvestigation showed that the groundwater had been contaminated by hydrocarbon arising from a\r\nfilling station in the area. The hydrocarbon contaminant plumes are characterized by relatively high\r\nresistivity values (> 200 -m) and were delineated to a depth of about 10 m. Hydrochemical results\r\nshowed that three of the sampled water have higher total dissolved solids (TDS) (>240 ppm) compared\r\nto the remaining water samples. The major ions identified includes (Na+, K+,Cl-,Mg2+,,Ca2+ and NO3\r\n-). The\r\ntotal dissolved solid (TDS) and electrical conductivity shows values not in agreement with WHO\r\nstandards. Twelve (12) Vertical Electrical Sounding (VES) stations were occupied along three traverse\r\nlines trending NW-SE and Nââ?¬â??S direction. The vertical electrical sounding results indicate maximum of\r\nfour subsurface layers-Top soil, hydrocarbon contaminated clay, weathered layer and the fresh\r\nbasement. The VLF-EM results assist in the delineation of non conductive zones which in most cases\r\ncoincides with the hydrocarbon contaminated plumes delineated by the 2D-pseudo section obtained\r\nfrom modeling the results obtained from Wenner profiling. The contaminant plume has migrated to a\r\nsignificant depth thus posing an inherent danger to the inhabitant of the area.
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