Pages: (140-151 )
Abstract
The use of open waste dumps for waste disposal remains common practice in most developing countries. This waste management method is grossly ineffective as the leachates generated from decomposed wastes infiltrate and contaminate the soil and groundwater of host communities and consequently pose serious environmental threat. It is therefore important to assess the leachate migration path with a view to providing remediation measures. 2D Wenner electrical resistivity profiling was carried out to detect and map leachate contamination around an abandoned solid waste dumpsite in Ido-Osun Southwestern Nigeria. The resistivity profiling measurements were taken along twelve traverses of length ranging from 70 m to 150 m around the dumpsite with the aid of a read-out ABAEM SAS 1000 resistivity meter, by using electrode spacing (a) of 5 m, 10 m, 15 m and 20 m. The data were interpreted by using 2D resistivity inversion procedures. The results of the study reveal several anomalous resistivity lows of values less than 10 Ωm typical of leachate plumes reflecting contamination around the dumpsite. Areas with relatively low resistivity greater than 10 Ωm are equally contaminated but with lower solute concentration. The waste dump has contaminated the subsoil within the distance of about 30 m away from its edges to depths greater than 7 m beneath the traverses. The contamination constitutes potential threat to soil and groundwater resources in the nearby developing community and are likely to be affected if prompt and adequate measures are not taken. Geochemical tests should be conducted to determine the concentration of the contaminants while appropriate remediation measures should be applied to forestall further spread of the contaminants toward the developing residential community.
Keywords: Dumpsite, leachate plumes, contamination, resistivity profiling, resistivity lows.,