Current through Register Vol. 63, No. 3, March 1, 2024
The collection and analysis of soil samples is required to
verify that a site meets the requirements of these rules. These samples must
represent the soils remaining at the site and must be collected after
contaminated soils have been removed or remediated. Each sample must represent
a single location; composite samples are not allowed. The number of soil
samples required for a given site and the location at which the samples are to
be collected are as follows:
(1) A
minimum of two soil samples must be collected from the site:
(a) These samples must be taken from those
areas where obviously stained or contaminated soils have been identified and
removed or remediated;
(b) If there
are two or more distinct areas of soil contamination, then a minimum of one
sample must be collected from each of these areas;
(c) The samples must be taken from within the
first foot of native soil directly beneath the areas where the contaminated
soil has been removed, or from within the area where in-situ remediation has
taken place;
(d) A field instrument
sensitive to volatile organic compounds may be used to aid in identifying areas
that should be sampled, but the field data may not be substituted for
laboratory analyses of the soil samples;
(e) If there are no areas of obvious
contamination, then samples must be collected from the locations specified in
sections (2)-(5) of this rule which are most appropriate for the
situation;
(f) If it is being
proposed that a pocket of contamination be left in place pursuant to OAR
340-122-0355(4),
then sufficient samples must be collected from the site in order to estimate
the extent, volume, and level of contamination in this pocket, and the
likelihood for the remaining contamination to result in unacceptable risk
levels due to volatilization into buildings.
(2) If water is not present in the tank pit:
(a) Soil samples must be collected from the
native soils located no more than two feet beneath the tank pit in areas where
contamination is most likely to be found;
(b) For the removal of an individual tank,
samples must be collected from beneath both ends of the tank. For the removal
of multiple tanks from the same pit, a minimum of one sample must be collected
for each 150 square feet of area in the pit.
(3) In situations where leaks have been found
in the piping, or in which released product has preferentially followed the
fill around the piping, samples are to be collected from the native soils
directly beneath the areas where obvious contamination has been removed.
Samples should be collected at 20 foot intervals.
(4) If water is present in the tank pit,
regardless of whether obvious contamination is or is not present, the
Department must be notified of this fact. The responsible person shall then
either continue the investigation under OAR
340-122-0240,
or do the following:
(a) Purge the water from
the tank pit and dispose of it in accordance with all currently applicable
requirements. This might require obtaining appropriate permits from the
Department or local jurisdictions;
(b) If the pit remains dry for 24 hours,
testing and cleanup may proceed according to the applicable sections of these
soil matrix cleanup rules. If water returns to the pit in less than 24 hours, a
determination must be made as to whether contamination is likely to have
affected the groundwater outside of the confines of the pit as indicated below:
(A) For the removal of an individual tank,
soil samples are to be collected from the walls of the excavation next to the
ends of the tank at the original soil/water interface. For the removal of
multiple tanks from the same pit, a soil sample is to be collected from each of
the four walls of the excavation at the original soil/water
interface;
(B) At least one sample
must be taken of the water in the pit regardless of whether obvious
contamination is or is not present. This sample shall be collected as required
by OAR
340-122-0345(4);
(C) The soil samples must be analyzed for TPH
and benzene, toluene, ethylbenzene, and xylenes (BTEX). The water sample must
be analyzed for BTEX at all sites, and for PAHs where releases of non-gasoline
fractions have occurred. Responsible persons may use TPH analyses on
groundwater samples as a preliminary screen for PAHs. The TPH method detection
limit must be no greater than 0.5 ppm. Any groundwater sample for which TPH is
detected must be analyzed for PAHs. These analyses must be made using the
methods specified in OAR
340-122-0218.
The results of these analyses must be submitted to the Department;
(D) The Department shall then determine how
the cleanup shall proceed as specified in OAR
340-122-0355(3).
(5) In situations where
tanks, pumps, and lines will remain in place in areas of suspected
contamination, the responsible person must submit a specific soil sampling plan
to the Department for its approval.
(6) In situations where TPH analysis
indicates that contamination is present due to a release from a waste oil tank,
at least one sample of the waste oil contaminated soils must be collected and
analyzed for volatile chlorinated solvents, volatile aromatic solvents, and
leachable metals (Cadmium, Chromium and Lead) using the analytical methods
specified in OAR
340-122-0218(1)(c).
Analysis for PCBs is also required if the contamination is from a waste oil
tank other than one used exclusively for storage of automotive waste
oils.
Stat. Auth.: ORS 465.400 & ORS 466.746
Stats. Implemented: ORS 465.200 - ORS 465.455 & ORS
466.706 - ORS 466.835
