Delineation of waste deposits by geoelectrical resistivity and induced polarization
Within the last decade - as a new technique - combined electrical resistivity (Ro) and
induced polarization (IP) geophysical methods were introduced to waste site exploration in NE Hungary. They have
originally been applied mainly for water and ore prospection worldwide.
Of all wellknown surface geophysical methods, the electrical resistivity method has
generally been proposed and applied for waste material mapping and water leakage tracing. Its portable and easy to
operate equipment facilitate rapid and cost effective Schlumberger-array vertical electrical sounding (VES). As
for the interpretation, it is reliable for the geological structure and helps to determine the presence and
approximate degree of a pollution, - but excludes the identification of the composition and character of the
"target", i.e. the natural agents or underground processes.
Originally the IP method is well known as an effective electromagnetic geophysical tool for
ore exploration, because both time-domain and frequency-domain IP measurements are capable to detect even small
amounts of metallic minerals. Recent years it becomes a useful geophysical method in the detection of waste sites,
contaminated debris. Time domain PI(t) polarizability curves can be constructed in the field, collecting the data
by Schlumberger electrode array, simultaneously with the resistivity sounding. Introducing TAU-transformation - a
special algorithm developed by Turai (Miskolc University) - for analizing the w(PI) spectrum function, after
solution the resulting different PI time-constant frequency values are characterizing the basic polarization
mechanisms and different physico-chemical processes in a burried public waste. Taking into account test
measurements and some previous experiments, the following time-constant (PI) values proved to be characteristic:
PI < 0.4 s - filtration; 0.2 s < PI < 0.8 s - membrane polarization; 0.6 s < PI < 1.2 s - electrochemical or redox
polarization; PI > 1.0 s - metallic or electrode potencial polarization.
Among the Háromkő Geopyisical and Geological Prospecting Co's works, case histories are
presented from Györöcske, Pásztó and Szerencs waste sites.