Passive
soil gas sampling technology is a powerful
and flexible site screening tool renowned
for it’s reliability and user friendliness,
making it the optimal choice particularly
when:
- Contaminants are present in low levels and
contain SVOCs as well as VOCs
- Contamination is deep under tight formations,
hardpacked soils, fractured bedrock
- The site is water saturated, underwater
or weather conditions are restrictive
- More invasive sampling could be compromising
or site access is limited
The samplers are usually deployed to a depth of
about 10 cm and exposed for about 72 hours before
being retrieved and sent to the laboratory. Analysis
can identify and quantify a broad range of VOCs
and SVOCs including halogenated compounds, petroleum
hydrocarbons, PAHs and many other compounds by
using any of several standard US EPA methods.
Map Contamination as well as Monitor
Changes
In addition to identifying and mapping
subsurface contamination ranging from
Vinyl Chloride to heavy low volatile
PAHs in soil and groundwater, passive
monitors can be used to provide proportional
compound specific measurements corresponding
to changes in underground source concentrations.
All this can be done from sample collection
points at or very near to the surface
of the ground. Because the samplers
continually collect soil gas over
time, they eliminate short term variation
problems associated with other soil
gas detection methods.
Performance Verified by the
US EPA
Passive Soil Gas Investigation Systems
have been evaluated by the US EPA
as part of their Environmental Technology
Verification Program. The technology
was assessed under the direction of
the EPA’s National Exposure
Research Laboratory. Rigorous QA protocols
were were required to ensure the demonstration
produced data of known and adequate
quality and the results of the assessment
were defensible.
The trial compared Passive Soil Gas
Sampling with the reference sampling
method, active soil gas sampling,
which provides a snapshot of the soil
gas environment at the time the sample
is collected.
The Passive System performed well
in detecting a range of VOCs. The
demonstration results indicated that
Passive Sampling can provide useful,
cost effective data for environmental
problem solving. The System was successful
in collecting soil gas samples in
clay and sandy soil and could detect
lower concentrations, and a wider
range of VOCs than the reference method.
Passive Sampling is
Sensitive Accurate Easy to Use Versatile
Cost Effective
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