INTEGRATED VERY LOW FREQUENCY ELECTROMAGNETIC (VLF-EM) GEOPHYSICAL AND HYDROGEOCHEMICAL STUDY OF ABEKU DUMPSITE IN IBADAN, SOUTHWESTERN NIGERIA

Abstract

Very Low Frequency Electromagnetic (VLF-EM) and hydrogeochemical studies have been integrated to measure ground conductivity and also determine the concentration of leachate derived contaminants in the groundwater around Abeku dumpsite in Ibadan, southwest Nigeria. Ten (10) VLF-EM profiles were occupied within and around the dumpsite fence. A water sample from wells was analyzed to determine the concentration of known pollutants. Qualitative interpretations of VLF-EM results indicate relatively high ground conductivity within the dumpsite, which decreases away from the waste dump. Ground conductivity is relatively higher in the south and east of the dumpsite which is located downhill of the groundwater hydrostatic head when compared with the north and west of the study area situated uphill of the hydraulic gradient. Hydrogeochemical analyses present NO₃^-, SO₄^2- and PO₄^2- ions concentration in the range of 9.24 – 13.64 mg/L, 3 – 12 mg/L and 0.33 – 1.07 mg/L respectively. The SO₄^2- and PO₄^2- ions concentrations are within permissible limits, while the NO₃^- ion concentration is slightly above the Federal Ministry of Environment’s standard for potable water in Nigeria.

Keywords: Abeku Dumpsite; Very Low Frequency Electromagnetic; Leachate; Contaminants
 

https://doi.org/10.2478/gse-2018-0011