• DOI:10.3997/1873-0604.2016048
• Corpus ID: 88511568

Spectral time-domain induced polarisation and magnetic surveying − an efficient tool for characterisation of solid waste deposits in developing countries

@article{Wemegah2017SpectralTI,
  title={Spectral time-domain induced polarisation and magnetic surveying − an efficient tool for characterisation of solid waste deposits in developing countries},
  author={David Dotse Wemegah and Gianluca Fiandaca and Esben Auken and Aboagye Menyeh and Sylvester Kojo Danuor},
  journal={Near Surface Geophysics},
  year={2017},
  volume={15},
  pages={75-84}
}

• D. D. Wemegah, G. Fiandaca, +2 authors S. Danuor
• Published 1 February 2017
• Geology
• Near Surface Geophysics

Time-domain induced polarisation and magnetic data were acquired to map and characterise the
decommissioned and un-engineered municipal solid waste disposal site of the Kwame Nkrumah
University of Science and Technology, located in the Kumasi Metropolis of Ghana. In this survey, 13
induced polarisation profiles 500–800 m long and 26 magnetic profiles 400–800 m long were acquired.
In addition, two boreholes were drilled to help in the interpretation of the geophysical data. The study
was carried out with the aim of determining the risk posed by the waste deposit to the quality of the soil
and the ground water system, which is the main potable water supply for the Secondary School, the
University Teaching Hospital and the Veterinary School, situated within the catchment area of the site.
Full-decay 2-D time-domain induced polarisation inversions in terms of Cole–Cole parameters were
used for interpreting the induced polarisation data. The chargeability, resistivity and normalised chargeability
distributions, together with the magnetic results, aided in a full characterisation of the site geology,
the waste and the associated pollution plume. In particular, clear contrasts in resistivity and the
polarisation parameters were found between the saprolite layer and the granitic bedrock, which are the
main lithological units of the area. Furthermore, it was found that the Kwame Nkrumah University of
Science and Technology waste deposit is characterised by a low-chargeability and low-resistivity signature
and that the low-resistivity area spreads out from the waste deposit into the permeable saprolite
layer, indicating the presence of a leachate plume. A fracture zone in the granitic bedrock beneath the
waste deposit, which is a potential conduit for leachate contamination of the ground water system, was
also identified. The study thus provides the information needed for assessing the future impact of the
waste on the water quality in the area and for designing risk-mitigation actions.