SOIL SAMPLING (Please Call to Schedule 503-236-3796)
Soil sampling is
the method used to determine if the tank has leaked and is the
first step in the certification process. Two samples are
taken within 6 inches of the center of each end of the tank, at
a depth range of 0"-24" below the bottom of the the tank.
This is done with either a Hand Auger or a Direct Push Core
Sampler (see Photos).
If one or more of
the sample locations is under concrete, then a 2 1/2 inch hole
must be bored out at that location to allow access for the
sampling tool. After the sampling is finished, the
concrete bore holes are filled with mortar and tooled flush with
the concrete. Most samples can be qualitatively tested in
the field at the time of sampling for the presence of petroleum
contamination. Samples are handled in an approved manner
that avoids possibility of cross-contamination and are
Samples are then
delivered to an accredited independent analytic testing
facility. Quantitative lab results are usually available
within 24 hours. Contamination levels are initially
measured in parts per million (ppm) of diesel and heavy oil.
If contamination levels are greater than 2,500 ppm, then
additional lab analysis must be performed called a BTEX
or BTEX-PAH (Benzene Toluene
EthyleneXylenes Polycyclic Aromatic
Hydrocarbons.) These results help determine what level
of remedial action, or clean-up, is required to close and
certify the site.
table show key concentration levels that determine the
requirements for site closure.
Soil Samples Lab Result
1-49 parts per million (ppm)
No action required but is advised due to
the known leakage.
Lab results reported to DEQ; Soil
Matrix level clean-up requirements.