LABORATORY AND FIELD RESULTS OF THE USE OF SPECTRAL INDUCED-POLARIZATION (SIP) METHOJ) FOR DETECTING ORGANIC AND INORGANIC CONTAMINANTS

Environmental applications of the induced polarization (1F) and the spectral induced polarization (spectral IP or SIP) methods, i.e., the possibility to detect organic and inorganic contaniinants in glacial soils, has been studied the Geological Survey of Finland (GTK) for some years. This presentation deals with the 1F of natural and contaminated soils (the membrane polarization), and gives two field examples; an area with an organic (hydrocarbon) contamination (Fig. 1), and an area with an inorganic (heavy metal) contarnination. THE SPECTRAL INDUCED POLARIZATION METHOD The 1F method and itS broadband extension, the spectral-IP method, were originally developed for ore exploration; the forrner largely at the 1950's, the later at the 1970's. In addition to exploration, 1F has been used in groundwater and oil prospecting. The idea of using the 1F also with environmental problems- such as detecting hydrocarbons and organic solvents in soils- was introduced in the middie of 1980's by Olhoeft (1985). Sadowski (1988) measured phase and amplitude spectra of clean day samples and organic-contaminated day samples and observed a pronounced phase peak due to toluene contamination (the same kind of spectrum had been reported already by Olhoeft). Vanhala, Sommen, an