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Probe Implants . |
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 “
Soil Gas Sampling Simplified ”
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Vapour
Sampling Probe Implants >
as pictured right, can be placed
in narrow boreholes using a hand
auger or drill rig. Once the target
depth is reached, the implant is
lowered into place and buried in
about 30 cm of clean dry sand. It
is then sealed with bentonite up
to the next sampling depth where
another probe can be set in place
with sand and sealed with bentonite,
as pictured on the right. > The
small tubing and implants allows
the sampling of multiple levels
from the same borehole (“nested
vapor wells”). The implants
are left in place and sampling can
be repeated as part of an ongoing
sampling program.
< Perforated Probe Tips
as pictured on the left are driven
into the ground using rods from
a conventional soil gas probe system
with a slide hammer or hammer drill.
The probe drive extension poles
are removed leaving the perforated
probe tip at the desired depth.
The tip is then buried with about
20 cm of sand, and sealed to the
surface with bentonite. |
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Sampling Procedures & Media
form an integral part of obtaining reliable
results. We work with our clients to
ensure the sampling & analytical
techniques satisfy the “data quality
objectives”. In addition, we are
able to prepare and supply the right,
solid sorbent tubes, gas bags and canisters
for sampling. For deep installations,
1/8 inch tubing can be used instead
of 1/4 inch tubing to reduce “internal
dead volumes” and reduce the problems
associated with purging large sample
volumes. For low level VOC sampling,
Teflon tubing should be used to reduce
the risk of contamination from the sample
tubing. The ends of the vapor sampling
tubing can be sealed off at the surface
with gas tight fittings suitable for
connection to sampling equipment such
as sorbent tubes and tedlar bags. If
required, the borehole can be terminated
at the surface with a variety of completions,
such as locking well covers.
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