Can resistivity methods be used to locate heave metal contaminated soils?

There are a large number of contaminated sites in Sweden requmng some form of remediation. In many cases the contaminants are heavy metals; here the level of contamination is often unknown. A typical investigation scheme includes chemical sampling to map the extension of the contaminant at the specific sites. Benefits could be derived from the use of additional methods, such as geophysics, to achieve a means of interpolating the result from the chemical sampling scheme. This is rather straightforward for some types of contaminants, e.g., brines that are highly conductive. An essential demand is, however, that there be a large enough contrast between composition of the natural geological environment and that of the contaminated area. In the case of high concentrations of heavy metals, a detectable physical anomaly can be expected, at least in theory. However, heavy metals are easily adsorbed into clays and organic soils. lts detection probably relies on the ohmic conductance, which can contribute to the current paths (i.e., not only electrolytic conductance) .