The Nature and Survey of Soil Pollution - Environmental Geomechanics - page 340

Pore water
resistivity
( Ω m )

Pore water
conductivity
( µ S/cm )

Resistivity
( Ω m )

Conductivity
( µ S/cm )

Material

Deltaic sands with
sea water intrusion

2 0.5 - -

Sea water - 0.2 - 50,000

Drinking water - >15 - <665

Landfill leachate

1−30 0.5−10

Clays 1−100 - -10,000−100 -

Silt and sand
(non-marine)

10−800 - 1,000−12 -

Sand and gravel
contaminated with
arsenic

1−10 0.5−4 -

Mining waste sites (sludges)

With acid leachate

1−40 0.0015−15 10,000−250 5,000−370

Without acid
leachate

70−100 15−50 145−100 665−200

Industrial sites

Sand contaminated
with organic
compounds

125 48 80 210

Sand contaminated
with inorganic
compounds

0.5−1.5 0.3−05 20,000−6000 33,000−20,000

Silts and sands
contaminated with
creosote

200−1000 75−450 - -

Silty clay
contaminated with
wood treatment
waste

- -

300−600 80−200

Table 12.3. Typical measurements of electrical resistivity and conductivity
of selected soils and their pore waters [CAM 94, ROB 98]

12.3.2.2. Impedance measurement at high dielectric constant frequency

Although the resistivity cone can be useful for detecting the presence of
contaminants in the subsurface, these devices offer little indication of the type of
contaminants encountered. The high frequency impedance sensors use
measurements of the dielectric constant and soil conductivity as a function of
frequency to better characterize the type of contaminant. These features are not yet
used in practice but seem to be promising. The original design of this sensor type is
from the work done by Delft Geotechnics [BRA 97], based on a penetrometer fitted
with a special tip (see Figure 12.9) that consists of a central pin and two concentric