  Geophysical methods are increasingly used to detect and locate illegal waste
disposal and buried toxic steel drums. This study describes the results of a
test carried out in clayey-sandy ground where 12 empty steel drums had
previously been buried at 4-5 m below ground level. This test was carried out
with three geophysical methods for steel-drum detection: a magnetometric
survey, electrical resistivity tomography with different arrays, and a
multifrequency frequency-domain electromagnetic induction survey. The data show
that as partially expected, the magnetometric and electromagnetic induction
surveys detected the actual steel drums buried in the subsurface, while the
electrical resistivity tomography mainly detected the changes in some of the
physical properties of the terrain connected with the digging operations,
rather than the actual presence of the steel drums.
