www.pca.state.mn.us
Minnesota Pollution Control Agency
651-296-6300 | 800-657-3864 or use your preferred relay service | Info.pca@state.mn.us
May 2024 | c-prp4-05
Available in alternative formats
Groundwater sample collection and analysis
procedures
Petroleum Remediation Program
1.0 Introduction
This document describes the procedures for collecting groundwater samples at Minnesota Pollution Control
Agency (MPCA) Petroleum Remediation Program (PRP) sites. It applies to temporary and permanent monitoring
wells, and water supply wells. Unforeseen circumstances during sampling may necessitate modifying these
procedures. When approval to modify procedures cannot be obtained in advance, contact the MPCA as soon as
possible to evaluate the need for resampling. Clearly note all deviations from the specified procedures on the
sampling information form used for each well and document them in the Monitoring report. Other MPCA
programs may have different sampling procedures; if sampling a monitoring well for multiple programs, follow
the most restrictive procedure.
The PRP conducts random on-site audits of field work. Give the PRP at least 48 hours’ notice prior to conducting
field work at sites under program oversight by submitting a field work notification via the MPCA Online services
portal. Prior notification of field work is mandatory and will be verified upon submittal of the results.
To assure data quality, the U.S. Environmental Protection Agency (EPA) requires the MPCA to maintain a Quality
Assurance Program Plan (QAPP) for the PRP. The QAPP defines the quality assurance/quality control (QA/QC)
procedures to be followed for the collection and analysis of environmental samples. This ensures sufficient
precision and accuracy of samples used in the PRP.
2.0 Analytical parameters and methods
Analytical parameters and methods required to fulfill PRP groundwater sampling requirements are outlined in
Section 9 and Appendices A to E.
The MPCA requires laboratory certification. See the MPCA Science and data webpage and Methods and analytes
requiring laboratory certification. Laboratories reporting data are required to include the name of the certifying
organization on analytical reports. Certification is currently required for fixed-base and mobile laboratories
analyzing volatile organic compounds (VOCs). Certification for mobile labs must meet the same requirements
established for fixed-base laboratories.
If a noncertified mobile laboratory is used for sample screening, split 10% of the samples with a certified fixed-
base laboratory. Data supporting site closure must be generated by an MPCA-recognized certified laboratory. In
appendices and tables, clearly label data generated by mobile laboratories and fixed-base laboratories. Use an
EPA-approved method or equivalent for all sample analyses, unless otherwise noted in this document. Provide
chromatograms for positive gasoline range organics (GRO) and diesel range organics (DRO) analyses. Properly
scale these chromatograms to show enough detail to allow for interpretation and identification.
Page 2 of 20
May 2024 | c-prp4-05
3.0 Field procedures
Exercise care to avoid cross-contamination of groundwater samples by adhering to these guidelines:
• Follow procedures for proper storage and transportation of equipment.
• Avoid contaminating equipment or sample bottles on site; do not set them on or near potential
contamination sources such as uncovered ground, contaminated vehicle, vehicle exhaust, etc.
• Avoid handling bottles or equipment with contaminated hands or gloves. All field crew personnel must
wear clean gloves made of appropriately inert material. Replace gloves when soiled and between
sampling locations.
• Carefully clean all non-disposable well purging or sampling devices.
3.1 Sampling order
When previous water quality data is available, begin with the least contaminated wells, and proceed to
increasingly contaminated wells. When contaminant distribution is unknown, begin with wells upgradient of
likely contaminant source(s), continue with downgradient wells, and finish with wells in or closest to suspected
contaminant source(s).
3.2 Water level measurements
Decontaminate water level probes between each sampling point by wiping or scrubbing off soil or other foreign
material, washing with a laboratory-grade detergent (Liquinox or equivalent)/clean-water solution, and rinsing
with tap water followed by a final rinse with distilled or deionized water. If the probe comes in contact with free
product or highly contaminated groundwater, wash equipment using a desorbing agent (dilute solution of water
and isopropanol or methanol) followed by a thorough tap water rinse and a final distilled or deionized water
rinse.
Prior to well purging or sampling, measure and record initial static water levels for all wells. Determine water
levels to the nearest 0.01-foot as measured from the surveyed reference point. Take water level measurements
at all applicable site monitoring wells and piezometers within the shortest practical time interval (the same day).
Reference the depth to water from the measuring point marked at the top of the innermost well casing. If the
well casing is unevenly trimmed, mark and survey the highest point on the casing for use as the measuring point.
Convert the water level measurement to water level elevation using the surveyed elevation of the top of each
well casing.
Record the well depth during each sampling event on the sampling form. The well depth may be measured with
the same instrument used to measure the water level. Record the well depth to the nearest 0.1 feet. In addition,
record the general physical condition of the well on the sampling form.
3.3 Light non-aqueous phase liquid measurements
If petroleum light non-aqueous phase liquid (LNAPL) is suspected or if strong petroleum odors are present in a
well, attempt to measure LNAPL thickness using an interface probe or bailer lowered slowly into the well. A tape
measure and water finding paste can also be used. Wells containing LNAPL are not normally sampled.
Immediately notify the Minnesota duty officer of all new LNAPL discoveries. For additional instruction, see Light
non-aqueous phase liquid management strategy.
Page 3 of 20
May 2024 | c-prp4-05
4.0 Well development and purging
4.1 Well development
Develop new permanent wells prior to sampling to ensure adequate hydraulic connection with the aquifer and
to remove any drilling fluids. Develop wells by pumping and surging until relatively clear water is produced.
Document development procedures, including the amount of water removed.
4.2 Well purging (standard purge and sample method)
This section discusses the standard purge method to be used when unpurged sampling (Section 4.4 below) is not
allowed.
For permanent monitoring wells, purge a minimum of three well-casing water column volumes before collecting
samples for laboratory analysis. Record the quantity of water purged on the sampling form. Prior to sampling
temporary monitoring wells, purge a smaller volume to reduce sample turbidity, to generate effluent for
measurement of field parameters in a flow cell if used, and to remove water that has leaked into the sampling
point through probe rod or auger flight joints during installation.
Purging equipment includes bailers or pumps. Bailers are only acceptable for purging permanent wells when
other equipment is not available or has failed. The sampling of groundwater using bailers is not recommended,
and should only be done in special circumstances and with approval from the MPCA. See Section 6.2 for more
details about the use of bailers. Pumps, except gas lift pumps and inertial pumps/tubing and check valve, can be
used to purge and sample any permanent or temporary well and are the preferred method for groundwater
sampling. Field crews should install wells with a diameter no less than 2 inches to allow for the use of a sampling
pump. Allowable pump types include:
• Submersible low flow, electric centrifugal pumps, such as Grundfos Redi-Flo2, etc
• Peristaltic suction lift pumps, with a maximum working depth of 20-25 feet
• Submersible, positive displacement bladder pumps
• Conventional submersible, electric centrifugal pumps, but only if permanently installed in the well
• Piston pumps
Do not attempt to sample groundwater with an inertial pump/tubing and check valve method. The “check
valve” method is known to produce poor quality groundwater samples due to removal of volatiles from the
water column through agitation.
Do not allow water that has entered the pump to re-enter the well during purging or sampling. This can occur if
using a pump without a check valve or in wells with slow recharge rates when the well is pumped dry and is
allowed to recover prior to sampling.
Wells with extremely slow recharge rates may require other purge methods. If normal purging is clearly
impractical, evacuate the well to near dryness and allow partial recovery twice. Following the second well
evacuation, sample the well when sufficient recovery has occurred. Clearly note the conditions and procedures
used on the sampling form as well as the amount of water purged in well volumes.
Purging should remove all the stagnant water in the well so it is replaced by fresh groundwater from outside the
borehole. Purge wells that do not have extremely slow recharge rates by withdrawing water from the top two
feet of the water column. Repeated vertical adjustment of the purging equipment intake may be necessary if the
water level drops. Set the pump rate at the lowest practical rate to avoid excessive drawdown and turbidity in
the well. Measure the field parameters immediately after or during well purging.
Page 4 of 20
May 2024 | c-prp4-05
4.3 Equipment decontamination
Decontaminate all sampling-related equipment that will be reused, including pumps, filtration devices, personal
protection gear, etc. The need for decontamination can be avoided by use of new disposable equipment that is
certified as clean. Thoroughly decontaminate non-dedicated pump tubing or use new or dedicated tubing at
each well. Use dedicated pumps or decontaminate by circulating decontamination fluids through the pump as
described below. Bailers must be laboratory cleaned or disposable. Decontaminate equipment between each
sampling point. After cleaning, inspect for residues or other substances that may survive normal cleaning. If
inspection reveals that decontamination was insufficient, implement additional measures as needed and
document. Decontaminate equipment in the following manner:
• Clean inside and out with a laboratory-grade detergent (Liquinox or equivalent)/clean-water solution,
applied with a scrub brush where practical.
• Rinse with tap water followed by a final rinse with distilled or deionized water.
• Inspect for remaining particles or surface film, and repeat cleaning and rinse procedures if necessary.
• Sampling equipment that contacts free product or heavily contaminated areas requires use of a
desorbing agent, dilute solution of water and isopropanol or methanol, followed by a thorough tap
water rinse and a final distilled or deionized water rinse.
Clean the internal surfaces of pumps and tubing by circulating decontamination fluids through them. Ensure that
a sufficient quantity of rinse water is circulated to completely flush out contaminants, detergents, and desorbing
agents if used. When transporting or storing decontaminated equipment, protect it in a manner that minimizes
the potential for contamination.
4.4 Unpurged groundwater sampling
Several studies indicate that in most situations unpurged groundwater sampling (samples collected without
prior purging of the well) produces data adequate for PRP needs. The PRP allows unpurged groundwater
sampling when all the following conditions are true:
• Wells are screened across the water table in unconsolidated and unconfined aquifers.
• Wells are screened in reasonably permeable formations, with a transmissivity of ≥ 50 ft
2
/day.
• Wells are redeveloped yearly to ensure a good hydraulic connection to the aquifer. The method
assumes adequate cross flow of water through the saturated interval of screen.
• Contaminants monitored are limited to petroleum volatile organic compounds (PVOCs) and/or GRO.
• LNAPL is not present.
Contact the MPCA if you have questions about the need for unpurged groundwater sampling at your site.
5.0 Field parameters
Field parameter measurement is required. The recommended method is to measure specific conductance,
temperature, pH, dissolved oxygen, and redox potential in the field utilizing a flow cell just prior to sampling or
individual field tests immediately thereafter. Record calibration information and all measurements on the
sampling form. Equipment calibration and maintenance logs must be maintained for the equipment used during
sampling events. The MPCA reserves the right to request these records.
5.1 Specific conductance
Soak the conductivity cell in distilled or deionized water for at least one hour before use and calibrate each day.
While making field measurements, record the true electrical conductivity (EC). Specific conductance (EC
corrected to 25 degrees Celsius) is calculated from the EC and the water temperature. Record both the EC and
specific conductance (SC) measurements on the sampling form.
Page 5 of 20
May 2024 | c-prp4-05
5.2 Temperature
Inspect the temperature probe to ensure it is in good operating condition. Record groundwater temperature to
the nearest 0.1 degrees Celsius.
5.3 pH
Measure pH using a direct reading probe following the instrument’s instruction manual. Keep the electrode tip
moist.
Before sampling each day, calibrate the pH meter by following at least a two-point calibration method and verify
with a third buffer. The reading should be within 0.1 unit for the pH of the third buffer. If the meter can hold the
slope well over time, routine calibration later in the day can be conducted with only one buffer. At a minimum,
verify the pH meter calibration every two hours by a single-point calibration at pH 7, for natural waters, before
taking measurements. Report pH readings to the nearest 0.1 unit.
After calibrating, allow the pH probe to equilibrate with fresh aquifer water for a minimum of five minutes
before the first pH measurement.
5.4 Dissolved oxygen
The recommended method for measuring dissolved oxygen is using a membrane electrode probe in a flow cell
or a luminescence-based sensor. Modified Winkler and Colorimetric ampoule methods can also be used under
proper field conditions. When measuring dissolved oxygen, take care to avoid turbulence and sample aeration.
When using a membrane electrode probe, follow the instrument’s instruction manual. Calibrate before taking
measurements at each new sampling point or every two hours. Replace the membrane every two to four weeks.
Follow the instrument’s instruction manual when using a luminescence-based sensor. Calibrate every eight
hours. Replace the probe cap every 365 days or more often if the cap becomes damaged or fouled.
Only stable meter readings are considered valid. If non-stable readings are observed, note and record the
non-stable measurements on the sampling form and in the monitoring report. Report dissolved oxygen readings
to the nearest 0.1 mg/L.
5.5 Redox potential
Measure redox potential in the field using a direct reading probe, preferably a flow cell. Take care to avoid
turbulence and sample aeration.
6.0 Sample collection
Use only laboratory-supplied sampling containers and preservative for groundwater samples. Following the
addition of chemical preservative (if used), observe sample containers for a reaction between the sample and
the chemical preservative. If a reaction is observed, collect unpreserved samples in new containers and note on
the chain-of-custody form.
6.1 Sampling wells using a pump
Pumps are the preferred sampling method. Record the type of pump used to sample each well on the sampling
form. Use pumps in the following manner:
• Adjust the flow rate to the lowest practical setting and maintain a continuous pumping rate. Slow-
recharging wells or wells with a small water column height may require cycling of the pump. Pumping
should be continuous, and sampling conducted immediately following purging. The pump must be
equipped with a check valve or operate to prevent water in the discharge line from flowing back into the
well.
Page 6 of 20
May 2024 | c-prp4-05
• Completely purge any final rinse water remaining in the sampling pump or discharge line by pumping at
least two tubing volumes through the pump before sample collection begins.
• Peristaltic pumps can be used for sampling; however, water that has moved through the pumping
mechanism must not be used for VOC/GRO samples. The following procedure is the only acceptable use
of peristaltic pumps for VOC/GRO samples:
• Run the pump until the suction line is filled with clean water, shut the pump off and remove the
suction line from the well, reverse the flow direction of the pump, discharging water from the
suction line into the sample vial. Samples other than VOC/GRO can be collected from the discharge
line.
• Do not allow water that has entered the pump to re-enter the well during purging or sampling.
6.2 Sampling wells using a bailer
Using bailers as a groundwater sampling method is discouraged.
However, bailers may be used during special circumstances with MPCA
approval. Special circumstances include but are not limited to:
• Equipment/pump breakdown during sampling.
• A petroleum sheen is observed on water (LNAPL).
• Slow recovery wells
Record the type of bailer used to sample each well on the sampling form. Use bailers in the following manner:
• Use only new, disposable, certified-clean high-density polyethylene or polytetrafluoroethylene bailers or
laboratory-cleaned stainless steel bailers for sampling. Reusable PVC bailers can be used for purging
only.
• Use a new retrieval line for each sampling point.
• Do not allow the bailer or line to touch the ground, a dirty ground cloth, or any other potentially
contaminated surface.
• Do not allow the bailer to free fall into the water column. The bailer should enter the water column as
gently as possible. A knot in the line referencing the groundwater level is useful.
• Try not to submerge the bailer much below the top to prevent mixing and to ensure water removal from
the top of the water column.
• Withdraw the bailer gently from the water column and bring it to the surface quickly.
• Keep the check valve on the bottom clear of sediment and in proper working order to minimize the
amount of water that drips back into the well.
• If the same bailer is not used for purging and sampling, discard the first two sample bailer volumes as
rinse water.
• Transfer the sample from the bailer to the sample container quickly while minimizing turbulence and
exposure to the atmosphere. The MPCA recommends the use of a bottom-emptying device.
6.3 Filling sample containers
Do not open sample bottles until they are ready to be filled. Follow these procedures:
• Keep the area surrounding the wellhead as clean as practical to minimize the potential for
contamination of samples.
• Minimize the potential for airborne contamination during sample collection. If vehicles or generators are
running during sample collection, fill containers upwind from engine exhaust sources. If conditions are
dusty, shield the sample collection area from wind-borne contamination.
• Use a clean pair of gloves at each new sampling point.
A well is considered to be fast-
recovering if it recovers to 80
percent or more of its static
conditions within 2 hours.
A well is considered to be slow-
recovering if it takes longer than
2 hours to recover to 80 percent
of its static water level.
Page 7 of 20
May 2024 | c-prp4-05
When sampling with a pump, hold the discharge tube as close as possible to the sample container without
allowing the sample tubing to contact the container. For VOCs, fill 40-mL purge-and-trap vials in a manner that
minimizes turbulence, air entrapment, and overfilling. Fill the bottle completely leaving a positive meniscus at
the top of the vial. After capping, invert the vial and tap with a finger to check for air bubbles. If bubbles are
present, discard the vial and fill a replacement. If the sample water effervesces (produces bubbles) when added
to an HCl-preserved vial, collect unpreserved samples and note the lack of preservation on the chain-of-custody
form. Analyze unpreserved samples within a seven-day holding time.
Collect multiple bottles to guard against loss by breakage and to allow for laboratory quality assurance.
6.4 Trip blanks, equipment blanks, duplicate samples, and field blanks
Collect sample blanks to detect background or method contamination and duplicate samples to evaluate
variability in analytical methods. Collect duplicate samples at wells suspected to have moderate or high levels of
contamination and in the same type of container as the corresponding primary samples. Assign duplicate
samples identification aliases on the sample bottle label and on the chain-of-custody form to avoid alerting
laboratories that the sample is a duplicate. Record the true identity of the samples on the sampling form.
A. When sampling temporary wells and during each permanent well sampling event, collect QA/QC
samples as follows:
• One trip blank for each cooler of VOCs, petroleum VOCs (PVOCs), low-level 1,2-dibromoethane
(EDB), and GRO.
• One temperature blank for each cooler of samples, except for lead or Resource Conservation and
Recovery Act (RCRA) metals if they are shipped in their own cooler.
• One equipment blank each day, by each field sampling crew, if re-useable sampling equipment is
used.
• At least one duplicate set per sampling event per analysis. If more than 10 wells are being sampled,
it is required that one duplicate be taken per every 10 samples.
• Two additional volumes of a sample are required for DRO water analysis. The laboratory will use
these for spike and spike duplicate samples. The rate of spike and spike duplicates is one per 10
samples.
Analysis parameters required for each type of QA/QC sample are:
• Trip blank: only for volatile organic analyses to include VOCs, PVOCs, low-level EDB, and GRO
• Equipment blank (reusable equipment only): VOCs, PVOCs, GRO/DRO
• Duplicates: all project parameters
See the table in Section 9 for further information.
B. Trip blank samples: Trip blanks for VOCs, PVOCs, low-level EDB, and GRO are filled and sealed by the
analytical laboratory with organic-free water. Trip blanks consist of a set(s) of pre-filled 40-mL purge-
and-trap vials and are to accompany each cooler containing VOC, PVOC, low-level EDB, or GRO samples.
These sample vials travel with the actual sample vials to and from the field in the cooler, to the well
head, etc., so the blanks are exposed to the same conditions as the actual samples. Fresh VOC vials and
a trip blank should be obtained from the laboratory for each sampling event. The vials are not opened
until analyzed in the laboratory along with the actual VOC, PVOC, low-level EDB, or GRO samples they
have accompanied. Note: more than one set of trip blanks may be needed depending on the specific
combination of analyses.
C. Equipment blank samples: Equipment blanks are used to determine the adequacy of the
decontamination procedures applied to reusable sampling equipment. Equipment blanks should be
collected using the same lot of sample containers, the same sampling equipment, and the same
sampling methods that are used to collect the other samples. Deionized blank water should contact all
the interfaces that the sample water will contact. These may include the sampling mechanism, ambient
air, sample container, and when applicable, pumps, tubing and filtration membranes.
Page 8 of 20
May 2024 | c-prp4-05
Place pumps and tubing that have been decontaminated or decontaminated pumps and new tubing
from the same lot as used in the well sampling into a short mock up section of well casing (assuming
there is not a permanent sampling pump installation), fill with clean water, and fill sample vials for the
equipment blank. When using bailers, collect the equipment blank by pouring clean water into the
freshly decontaminated bailer and then filling the sample vials.
D. Duplicate samples: Collect duplicate samples by sequentially filling all containers as close together in
time as practical. Collect at least one field duplicate sample per sampling event per analysis.
E. Field blank samples: Field blanks are used to evaluate possible cross-contamination of samples from the
ambient field conditions that are present at the sampling location. Deionized water is poured into the
appropriate sample vials and shipped to the laboratory with the other samples. Field blanks are not
required at every site and are typically collected when cross-contamination from the ambient field
conditions is suspected.
6.5 Sampling submerged water table wells
Detection of both free and dissolved phase products requires proper placement of monitoring well screens.
Water table monitoring well screens, including temporary wells, must intersect the water table. However, there
are sites where there are significant fluctuations in the water table, or where low permeability soils make it
difficult to properly place the well screen. In these situations, follow the guidance below.
• Do not collect analytical samples from permanent water table wells where the screen top is submerged
more than two feet below the water table, as measured from the top of the well screen, not the sand
pack.
• If a permanent water table well screen is submerged less than two feet, try to lower the water table
during well purging. If well purging lowers the water level to intersect the well screen, sample the well
as before. Samples collected in this manner are sufficient for routine monitoring, but may not be
considered valid for site closure requirements.
• If a permanent water table well screen is submerged for more than three sampling quarters, a new well
may be necessary.
• Unpurged sampling of submerged screens is not allowed (see Section 4.4).
Note: These sampling requirements do not apply to monitoring wells deliberately screened below the water
table to detect vertical contaminant migration.
6.6 Water supply well sampling
The goal of water supply well sampling is to collect a representative sample of the groundwater supplying a well.
To ensure a representative sample, carefully evaluate the water supply system, including the well, water line,
water treatment units, such as water softeners or filters, and other appurtenances, such as water heaters or
pressure tanks. Identify a sampling location and determine how much water to purge prior to sampling. Sample
collection procedures must minimize sample disturbance and potential cross contamination. Follow the
protocols listed below when sampling a water supply well and document site-specific procedures on the
sampling form.
• Identify potential sampling points located ahead of water treatment and other appurtenances and
select the one located closest to the well. This will often be at or near the pressure tank. Identify the
sampling point and any appurtenances between the sampling point and well on sampling forms. If water
samples must be collected after the pressure tank, denote whether the tank is a captive air (i.e.,
bladder) tank or a conventional (i.e., non-bladder) tank.
• Follow the steps below to determine the purge water volume:
Step 1: Calculate the volume of standing water in the water line and any appurtenances between the
well and the sampling point.
Page 9 of 20
May 2024 | c-prp4-05
Step 2: Determine the volume of well water to purge based on the available well information using one
of the three options listed below in order of preference:
• If a Minnesota Department of Health well record or reliable well construction information is
available, calculate three well casing water column volumes. Add this volume to the volume
from Step 1 and purge the total volume before sampling.
• If well construction is unknown, measure field parameters (pH, temperature, and specific
conductance) during purging until readings are stable after purging the volume calculated in
Step 1.
• If well construction is unknown and a meter to measure field parameters is not available, purge
the well for a minimum of 10 minutes at full discharge rate after purging the volume calculated
in Step 1.
The preferred sampling point is often located in a basement or utility area. If a drain is present, it may be
possible to purge directly from the sampling point. If a drain is not available near the sampling point, purge the
water system from another location with a drain, such as kitchen sink, bathroom sink, and bathtub, or outside
tap. Carefully monitor the discharge point during purging to avoid flooding or water damage. Record the volume
of water purged on the sampling form.
• Open the sampling point tap and collect the sample immediately after purging. The water flow rate
during sampling should be the minimum required to maintain a continuous flow while minimizing
aeration. Observe the following precautions while filling sample containers:
• Remove the aerator from the tap, if present.
• Do not sample through a garden hose or any other attachments or filters on the tap.
• Do not allow sampling containers to contact the tap during filling.
• If sampling from a tap with hot and cold water, purge and fill containers with only cold water.
6.7 Sampling for water line permeation assessment
The purpose of the sampling is to obtain a worst-case sample from the section of water line that passes through
the contaminated area of concern. Use the following sampling protocol at petroleum release sites where water
line permeation is a potential exposure pathway.
For water supply systems served by an on-site well:
• Collect water samples after the water has sat in the supply line for at least 8 hours.
• Identify potential sampling points located prior to water treatment units, such as water softeners or
filters, and other appurtenances, such as water heaters or pressure tanks. After identifying potential
sampling points, select the one that is located closest to the potentially impacted section of water line.
• Calculate the volume of water standing in the supply system between the sampling point and the
potentially impacted water line section. This calculation should include the water in the lines and any
appurtenances if samples cannot be collected prior to the appurtenances. Note: if water samples have
to be collected after the pressure tank, denote whether the tank is a captive air (i.e., bladder) tank or a
conventional (i.e., non-bladder) tank.
• Open the sampling tap and collect the water samples immediately after the volume of water
determined in Step #3 has been purged from the system.
For water supply systems served by a municipal or community water supply system:
• Identify potential sampling points located as close as possible down gradient to the potentially impacted
section of water line. Note: potentially impacted sections of water lines can include both water mains
and individual service laterals. If possible, sampling points should be located ahead of water treatment
units, such as water filters or dechlorinators, and other appurtenances, such as water heaters.
• Ideally, collect water samples after water has sat in the water line for at least 8 hours. In some scenarios,
such as water mains or high usage service laterals, this may not be possible. In those instances, collect
water samples during low flow times if it is feasible to do so.
Page 10 of 20
May 2024 | c-prp4-05
• Calculate the volume of water standing in the supply system between the sampling point and the
potentially impacted section of water line. This calculation should include the water in the lines and any
appurtenances if samples cannot be collected prior to the appurtenances.
• Open the sampling tap and collect the water samples immediately after the volume of water
determined in Step #3 has been purged from the system.
7.0 Documentation of sampling event
Record all data and document procedures used on a sampling form. Consultants and responsible parties may
develop their own forms providing they are specifically designed for documentation of field activities and
collection of field data. The sampling form provides a means to verify whether correct procedures were followed
during several key steps in the groundwater sampling event. The sampling form must include at a minimum:
sampling point ID, sampling personnel, field conditions, type of well, well depth, water level, calculation of purge
volume, purging method, sampling order, field parameters, and other relevant observations, such as odor, color,
and sheen. Attach a copy of the sampling form(s) in the appendices of the Investigation report or Monitoring
report.
7.1 Chain of custody
Initiate a chain-of-custody form in the field at the time of sampling and include a copy in the Monitoring report.
7.2 Exceptions to sampling procedures
Note any exceptions to routine groundwater sampling procedures on the sampling form and in the Monitoring
report. Also, include the following details in the Monitoring report:
• The reason for the exception.
• The identification of all samples and individual parameters that may have been impacted either in terms
of the quantitative or legal integrity of their reported values.
• The significance of the potential impacts to the integrity of each sample.
• Footnote any potentially significant impact on sample integrity when reporting or referring to the
results.
7.3 Field conditions
Record field conditions during the sampling event on the sampling form. Include a statement in the Monitoring
report regarding the likelihood that any unusual field conditions had a significant impact on the sampling results.
Report the following field conditions:
• Air temperature
• Wind speed
• Precipitation/moisture
• Ambient odors
• Airborne dust
8.0 Sample preservation, handling, and transport
Preserve all samples in the field immediately after sample collection by placing the samples in an insulated
cooler containing ice. Ensure enough samples are collected to allow for possible breakage and quality assurance
needs. Take measures to prevent water damage to paper work and sample labels. Include a container of water
for the temperature blank and record the temperature just before transporting samples and upon receipt at the
laboratory to verify that samples were kept refrigerated. Samples that are hand delivered directly to the
laboratory on the day they were collected may not meet the 4 ± 2
degrees Celsius temperature specification. In
Page 11 of 20
May 2024 | c-prp4-05
this situation it must be demonstrated that samples are in the in the process of cooling as evidenced by the
temperature blanks being at 4 ± 2
degrees Celsius.
9.0 Analytical parameters and laboratory methods
This table specifies analytical parameters for groundwater samples at PRP sites. Use an EPA-approved method or
equivalent for all sample analyses, unless otherwise noted.
Petroleum product
Parameter
Leaded gasoline
A/B, C, E, I
Unleaded gasoline, ethanol-blended fuel (see Note 1)
A/B, C
Unused petroleum products: fuel oil, motor oil, diesel fuel, kerosene, jet fuels
A, D, H
Used oil: used motor oil, other used oils (see Notes 3 and 4)
A, D, F, G, H
Unknown petroleum or hydrocarbons mixture
A, C, D, F, G, H, I
Other petroleum products
Site specific
Hydraulic fluids
A, D, G, H
Note: Drinking water supply samples must be analyzed for VOCs every event.
A. Volatile organic compounds (VOCs) by the most recent version of EPA Method 8260 (see Note 5). The
VOC target analyte list is found in Appendix A. EPA Method 8260 SIM may be required for groundwater
sample results to achieve lower RLs. For some chemicals, the drinking water standard is lower than the
required Method 8260 report level (RL) listed in Appendix A. EPA Method 524 may be required for
drinking water supply samples to achieve lower RLs (see Note 6).
B. Petroleum VOCs (PVOCs) by the most recent version of EPA Method 8260 or Method 8021 (see Note 5).
PVOC analysis QA/QC procedures are found in Section 10. The PVOC target analyte list is found in
Appendix B.
C. Wisconsin Department of Natural Resources Modified Gasoline Range Organics GRO method (see Notes
7 and 9)
D. Wisconsin Department of Natural Resources Modified Diesel Range Organics DRO method (see Notes 8,
9, and 10)
E. Lead, total (Only at point of use for groundwater. Contact the MPCA when dealing with
surface water.)
F. Resource Conservation and Recovery Act (RCRA) metals - arsenic, barium, cadmium, chromium, lead,
mercury, selenium, and silver (see Note 4)
G. Polychlorinated biphenyls (PCBs) using the most recent version of EPA Method 8082 by the Aroclor
method. See Appendix C for specific Aroclors. Analysis for PCBs should be completed for hydraulic fluids
used in elevators and other hydraulic fluids subject to high heat prior to the 1980s.
H. Polycyclic aromatic hydrocarbons (PAHs) by the most recent version of EPA Method 8270. PAH analysis
QA/QC procedures are found in Section 10. The PAH target analyte list is found in Appendix D.
a. Note: The MPCA will determine the need for PAH analysis. Contact the MPCA if a drinking water
aquifer is impacted by fuel oil or heavy petroleum.
I. Low-level analysis for 1,2-dibromoethane (EDB) and 1,2-dibromo-3-chloropropane (DBCP) by EPA
Method 8011. EDB/DBCP analysis QA/QC procedures are found in Section 10. The EDB/DBCP target
analyte list is found in Appendix E. Standard operating procedures outlining laboratory QA/QC limits
should be provided to the MPCA for review prior to completing this analysis (see Note 2).
a. Note: The MPCA will determine the need for low-level EDB/DBCP analysis. Contact the MPCA to
discuss the need for this analysis if a drinking water aquifer is impacted by leaded gasoline or an
unknown petroleum mixture.
Page 12 of 20
May 2024 | c-prp4-05
Notes
1. For ethanol-blended fuel releases, see Investigation requirements for ethanol-blended fuel releases for
additional sampling requirements.
2. For leaded fuel release sites, see Investigation requirements for fuel releases containing lead scavengers.
3. Do not confuse used oil with waste oil. Used oil means any oil that, because of use, has become
contaminated by physical or chemical impurities. Examples of used oil include, but are not limited to, motor
oils, quench oils, metal cutting oils, and hydraulic fluids. Waste oil means virgin oil that is discarded or spilled
before use.
4. During investigation at used oil sites, collect samples for all parameters listed (VOCs, DRO, RCRA metals, and
PCBs), but direct your laboratory to analyze only the VOC and DRO samples initially. If any of these
compounds are detected, proceed with analysis of the RCRA metals and PCB samples. RCRA metals analysis
for water samples should be a total analysis. Subsequent analysis for the dissolved metals may be required.
Extract and analyze all samples within holding times.
5. VOC analysis by the most recent version of EPA Method 8260 is required for all temporary monitoring well
samples and during the first two sampling events at permanent monitoring wells. If VOCs other than PVOCs
are present, the MPCA may require continued sampling for VOCs. Note that if EDB or 1,2-dichloroethane
(DCA) are present, continued VOC sampling is required (see Figure 1). If lower RLs are needed for sites with
DCA or EDB, EPA Method 8260 SIM can be used. However, if the contaminants present did not originate
from a petroleum tank release, the costs for continued VOC sampling may not be reimbursable through
Petrofund. When gas chromatography/mass spectrometry (GC/MS) is not completed based on the
instructions stated above, or holding times are not met, additional sampling will be necessary for
confirmation purposes. In permanent monitoring wells, if only petroleum hydrocarbons are present, with
the exception of EDB or DCA, reduce the analyte list to PVOCs beginning with the third sampling event. The
laboratory procedure should be purge-and-trap GC or GC/MS. Store all samples at 4 ± 2 degrees Celsius and
deliver them to the laboratory within 4 days from collection. Sample analysis occurs within 14 days of the
collection date if preserved, otherwise analyzed within 7 days. The RLs for all parameters should be equal to
or better than the program-required RLs listed in Appendices A and B, with quality control procedures
specified in the most recent version of EPA Method 8260.
6. Drinking water supply samples may be analyzed using EPA Method 8260; however, the RLs may not be low
enough to quantify certain chemicals at or below their health-based standard. Analyze drinking water
samples using the most recent version of EPA Method 524 if lower RLs are needed. If residual chlorine may
be present in the sample, preserve the samples with ascorbic acid instead of hydrochloric acid.
7. This is a purge-and-trap, GC procedure that uses a ten-component blend of gasoline compounds for the
quantification standard. The samples must be cooled to 4 ± 2 degrees Celsius, received by the laboratory
within 4 days from collection, and analyzed within 14 days of the collection date. The method detection limit
shall be no more than 100 µg/L for water.
8. This is a solvent extraction, direct injection, GC procedure that uses a ten-component blend of typical diesel
oil components for the quantification standard. Collect water samples in 1-liter amber bottles. The samples
must be kept at 4 ± 2 degrees Celsius, extracted by the laboratory within 7 days from collection, and
analyzed within 47 days of the collection date. The reporting limit shall be no more than 100 µg/L for water.
9. Separate samples are required for GRO and DRO analyses.
10. The DRO analysis method can have false positives that lead to elevated results caused by interference of
naturally occurring non-petroleum matter, such as plant detritus and peat in the form of polar organic
compounds. However, some petroleum products and petroleum degradation byproducts are also known to
have significant levels of polar organic compounds. The DRO analysis method is a very useful screening
method, but may not provide an accurate determination of petroleum compounds for making site decisions.
When false positives are suspected, cleanup of extracts to remove non-petroleum compounds may be
necessary. One of the most widely uses DRO cleanup methods is the DRO silica gel cleanup method (SGC).
Page 13 of 20
May 2024 | c-prp4-05
SGC works by attaching to and eliminating polar organics, which are typically associated with natural organic
matter. However, some precautions should be taken when using the SGC method in groundwater
investigations, as groundwater does not contain notable levels of naturally occurring organic matter;
therefore the SGC method may remove petroleum products from that sample. The following steps should
be followed if and when the DRO SGC method is used at a site investigation:
• Groundwater samples must always be split; one analyzed for DRO with SGC, and one without SGC.
Analytical results must be paired in this way to provide meaningful data.
• Collect groundwater samples from upgradient wells and/or areas where contamination is known to not
be present, to document background DRO levels.
• Include chromatograms for both pre- and post-cleanup samples. See Section 10 for laboratory QA/QC
procedures for DRO cleanup.
• Samples transported incorrectly or analyzed beyond the required holding times are considered invalid.
10.0 Required laboratory quality assurance/quality control
A. PVOC analysis: Analyze samples for the target analytes listed in Appendix B using the most recent
version of EPA Method 8260 or Method 8021. Follow all quality control (QC) elements defined in the
method, as well as the QC procedures listed below.
• Initial calibration: The initial calibration curve must contain at least five calibration points. For
Methods 8260 and 8021, the r
2
for each curve must be greater than or equal to 0.990, or the r for
each curve must be greater than or equal to 0.995. If the ratio of response to concentration is
constant (<15% relative standard deviation for Method 8260 and <20% relative standard deviation
for Method 8021), linearity can be assumed and the average response factor can be used in place of
a calibration curve. The recovery (accuracy) for each point in the curve must be 70% to 130% except
for the lowest point in the curve, which must be 60% to 140%. The lowest calibration point in the
curves shall be at or below the analyte report level. If a sample concentration exceeds the highest
calibration standard from the initial calibration, the sample must be diluted into the calibration
range and re-analyzed.
• Continuing calibration verification: Analyze one low-level standard at the RL and one mid-level
calibration verification standard prior to the samples. Bracket the batch of samples with a second
mid-level calibration verification standard. In each 12-hour period, up to 20 environmental samples
can be analyzed between standards. The percent recovery (%R) for the target analytes in the low-
level standard should be between 60% and 140% of the true value. The %R for the target analytes in
the mid-level standards should be between 70% and 130% of the true value, with a %D of less than
or equal to 30%.
• Initial demonstration of capability: Analyze 4-7 replicate mid-level check standards. Percent
recovery (%R) must be equal to 70-130%. The percent relative standard deviation (%RSD) must be
less than 20%.
• Method detection limit/report level: Method detection limits (MDLs) and report levels (RLs) are
determined annually or after a major change to the instrument conditions. The MDLs are
determined per the procedure defined in 40 CFR 136, Appendix B. Analyze a minimum of seven
standards. The RL should be approximately three to five times the MDL. The lowest calibration point
in the curves shall be at or below the analyte report level. If the accuracy of the RL standard does
not meet the 60% to 140% criteria, a new RL standard is chosen and analyzed until the accuracy
criteria are met.
• Batch quality control: A batch is defined as up to 20 environmental samples analyzed in a 12-hour
sequence. At a minimum, each batch must contain a method blank, a laboratory control sample
(LCS), and a MS/MSD pair. If there is not enough sample to prepare and analyze a MS/MSD pair, a
laboratory control sample duplicate (LCSD) is prepared and analyzed.
Page 14 of 20
May 2024 | c-prp4-05
• Method blanks: Analyze one method blank per QC batch of 20 samples or less. The concentration of
PVOCs in the method blank must be less than the associated report level. If the method blank is
contaminated, measures must be taken to eliminate the problem. Affected samples must then be
re-extracted and re-analyzed. If the contamination cannot be eliminated, the results must be
qualified to indicate the problem. All concentration levels for the affected target analyte that are
less than ten times the concentration in the blank should be qualified with a “B” to indicate that the
sample results may contain a bias related to the blank contamination. Concentrations of the
affected analyte that are above ten times the blank contamination will not need to be qualified.
• Accuracy/precision: One LCS is required per batch. The %R must be between 70% and 130%. One
MS and MSD is required per batch. The %R for each analyte in the MS/MSD must be between 70%
and 130% with a relative percent difference (RPD) of less than or equal to 30%.
• Holding time: The samples must be analyzed within 14 days of sample collection.
• Confirmation analysis: For Method 8021, confirmation analysis using a dissimilar detector or a
column of different polarity must be performed, or by GC/MS analysis. The agreement between the
quantitative results is evaluated by calculating the RPD between the two results. The formula is:
=
(
1
–
2
)
(
1
+
2
) ∗ 2
100
The RPD should be ≤40%. If one result is significantly higher, check the chromatograms to see if an
obviously overlapping peak is causing the high result. If no overlapping peaks are noted, examine
the baseline to determine if there were any data system problems during peak integration.
If no anomalies are noted, report the higher result and add a flag that alerts the data user of the
disparity between the results on the two detectors or columns.
B. PAH analysis: Analyze samples for the target analytes in Appendix D using the most recent version of
EPA Method 8270. 1-Methylnaphthalene and 2-methylnaphthalene are included in the list of PAH target
analytes for the PRP. Follow all QC elements defined in the method, as well as the QC procedures listed
below.
• Initial calibration: The initial calibration curve should contain at least five calibration points. The r
2
for each curve must be greater than or equal to 0.995. If the ratio of response to concentration is
constant (<20% relative standard deviation), linearity can be assumed and the average response
factor can be used in place of a calibration curve. The recovery (accuracy) for each point in the curve
must be 70% to 130% except for the lowest point in the curve, which must be 60% to 140%. The
lowest calibration point in the curves shall be at or below the analyte report level. If a sample
concentration exceeds the highest calibration standard from the initial calibration, the sample must
be diluted into the calibration range and re-analyzed.
• Continuing calibration verification: Analyze one low-level standard at the report level (RL) and one
mid-level calibration verification standard prior to the samples. Bracket the batch of samples with a
second mid-level calibration verification standard. In each 12-hour period, up to 20 environmental
samples can be analyzed between standards. The percent recovery (%R) for the target analytes in
the low-level standard should be between 60% and 140% of the true value. The %R for the target
analytes in the mid-level standards should be between 80% and 120% of the true value, with a %D
of less than or equal to 20%.
• Initial demonstration of capability: Analyze 4-7 replicate mid-level check standards. Percent
recovery (%R) must be equal to 70-130%. The percent relative standard deviation (%RSD) must be
less than 20%.
• Method detection limit/report level: MDLs and RLs are determined annually or after a major
change to the instrument conditions. The MDLs are determined per the procedure defined in 40 CFR
136, Appendix B. Analyze a minimum of seven standards. The RL should be approximately three to
five times the MDL. The lowest calibration point in the curves shall be at or below the analyte report
level. If the accuracy of the RL standard does not meet the 60% to 140% criteria, a new RL standard
is chosen and analyzed until the accuracy criteria are met.
Page 15 of 20
May 2024 | c-prp4-05
• Batch quality control: A batch is defined as up to 20 environmental samples extracted in the same
24-hour period. At a minimum, each batch must contain a method blank, a LCS, and a MS/MSD pair.
If there is not enough sample to prepare and analyze a MS/MSD pair, a LCSD is prepared and
analyzed.
• Method blanks: Analyze one method blank per QC batch of 20 samples or less. The concentration of
PAHs in the method blank must be less than the associated report level. If the method blank is
contaminated, measures must be taken to eliminate the problem. Affected samples must then be
re-extracted and re-analyzed. If the contamination cannot be eliminated, the results must be
qualified to indicate the problem. All concentration levels for the affected target analyte that are
less than ten times the concentration in the blank should be qualified with a “B” to indicate that the
sample results may contain a bias related to the blank contamination. Concentrations of the
affected analyte that are above 10 times the blank contamination will not need to be qualified.
• Accuracy/precision: One LCS is required per batch. The laboratory should generate in-house limits
for accuracy. The % recoveries should be between 50% and 150%. One MS and MSD is required per
batch. The laboratory should generate in-house limits for accuracy and precision. The % recoveries
for each analyte in the MS/MSD should be between 50% and 150% with a RPD of less than or equal
to 30%.
• Surrogates: Surrogates are added to all environmental and QC samples. The laboratory should
generate in-house limits for surrogate recoveries. The % recoveries should be between 50% and
150%.
• Holding time: The samples should be extracted within 7 days of collection and analyzed within
40 days of extraction.
C. DRO cleanup: Groundwater extracts may be cleaned up prior to DRO analysis using three methods,
either separately or in combination. The methods include:
1) EPA Method 3630C, silica gel cleanup
2) EPA Method 3650B, acid/base partitioning, and 3) EPA Method 3611B, alumina column cleanup.
When DRO cleanup is requested, pre-cleanup analysis should be completed prior to conducting
the cleanup. If there are no detections in the pre-cleanup analysis, the laboratory should not
conduct the cleanup and post-cleanup analysis.
DRO clean-up results will be accepted only if quality assurance documentation shows results that meet
acceptance criteria, i.e. no significant loss of petroleum compounds. The quality control acceptance
criteria for the clean-up results will be as follows:
• At least one method blank, one laboratory duplicate, one matrix spike, and one laboratory
control sample must be run through the complete clean-up and analysis process for up to 20
samples (1/20).
• The laboratory must provide a narrative of the entire clean up and analysis process. They must
also provide pre- and post-cleanup results and compare the pre-cleanup chromatogram with
that of the post-cleanup chromatogram for every sample when cleanup is completed.
• The relative percent difference (RPD) between sample duplicates, matrix spike pairs, or
laboratory control sample pairs must be less than or equal to 20%. However, if the
concentration of the target analyte in the sample/sample duplicate is less than five times the
report level, the difference between duplicates is used to measure precision. The difference
must then be less than or equal to the RL.
D. 1,2-Dibromoethane (EDB) and 1,2-Dibromo-3-chloropropane (DBCP) in groundwater: Analyze water
samples for these target analytes using the most recent version of EPA Method 8011. All QC elements
defined in the method must be followed. Laboratories must also incorporate the quality control
procedures listed below.
• Initial calibration: The initial calibration curve must contain at least five calibration points. The r
2
for
each curve must be greater than or equal to 0.990, or the r for each curve must be greater than or
Page 16 of 20
May 2024 | c-prp4-05
equal to 0.995. If the ratio of response to concentration is constant (<20% relative standard
deviation), linearity can be assumed and the average response factor can be used in place of a
calibration curve. The recovery (accuracy) for each point in the curve must be 70% to 130% except
for the lowest point in the curve, which must be 60% to 140%. The lowest calibration point in the
curves shall be at or below the analyte report level. If a sample concentration exceeds the highest
calibration standard from the initial calibration, the sample must be diluted into the calibration
range and re-analyzed.
• Continuing calibration verification: Analyze one low-level standard at the RL and one mid-level
calibration verification standard prior to the samples. Bracket the batch of samples with a second
mid-level calibration verification standard. In each 12-hour period, up to 20 environmental samples
can be analyzed between standards. The percent recovery (%R) for the target analytes in the low-
level standard should be between 60% and 140% of the true value. The %R for the target analytes in
the mid-level standards should be between 70% and 130% of the true value, with a %D of less than
or equal to 30%.
• Initial demonstration of capability: Analyze 4-7 replicate mid-level check standards. Percent
recovery (%R) must be equal to 70-130%. The percent relative standard deviation (%RSD) must be
less than 20%.
• Method detection limit/report level: Method detection limits (MDLs) and RLs are determined
annually or after a major change to the instrument conditions. The MDLs are determined per the
procedure defined in 40 CFR 136, Appendix B. Analyze a minimum of seven standards. The RL should
be approximately three to five times the MDL. Report results to the MDL and flag estimated
concentrations. The lowest calibration point in the curves shall be at or below the analyte report
level. If the accuracy of the RL standard does not meet the 60% to 140% criteria, a new RL standard
is chosen and analyzed until the accuracy criteria are met.
• Batch quality control: A batch is defined as up to 20 environmental samples extracted in the same
24-hour period. At a minimum, each batch must contain a method blank, a LCS, and a MS/MSD pair.
If there is not enough sample to prepare and analyze a MS/MSD pair, a LCSD is prepared and
analyzed.
• Method blanks: Analyze one method blank per QC batch of 20 samples or less. The concentration of
EDB or DBCP in the method blank must be less than the associated report level. If the method blank
is contaminated, measures must be taken to eliminate the problem. Affected samples must then be
re-extracted and re-analyzed. If the contamination cannot be eliminated, the results must be
qualified to indicate the problem. All concentration levels for the affected target analyte that are
less than ten times the concentration in the blank should be qualified with a “B” to indicate that the
sample results may contain a bias related to the blank contamination. Concentrations of the
affected analyte that are above ten times the blank contamination will not need to be qualified.
• Accuracy/precision: One LCS is required per batch. The %R must be between 70% and 130%. One
MS and MSD is required per batch. The %R for each analyte in the MS/MSD must be between 65%
and 135% with a RPD of less than or equal to 30%.
• Holding time: The samples should be extracted and analyzed within 14 days of sample collection.
• Confirmation analysis: Confirmation analysis using a column of different polarity must be
performed.
Page 17 of 20
May 2024 | c-prp4-05
Appendix A: Target analyte for volatile organic compounds
Chemical name
CAS #
Report level (µg/L)
1,1,1,2-Tetrachloroethane
630-20-6
1.0
1,1,1-Trichloroethane
71-55-6
1.0
1,1,2,2-Tetrachloroethane
79-34-5
1.0
1,1,2-Trichloroethane
79-00-5
1.0
1,1,2-Trichlorotrifluoroethane
76-13-1
1.0
1,1-Dichloroethane
75-34-3
1.0
1,1-Dichloroethene
75-35-4
1.0
1,1-Dichloropropene
563-58-6
1.0
1,2,3-Trichlorobenzene
87-61-6
1.0
1,2,3-Trichloropropane
96-18-4
1.0
1,2,4-Trichlorobenzene
120-82-1
1.0
1,2,4-Trimethylbenzene
95-63-6
1.0
1,2-Dibromo-3-chloropropane
96-12-8
5.0
1,2-Dibromoethane
106-93-4
1.0
1,2-Dichlorobenzene
95-50-1
1.0
1,2-Dichloroethane
107-06-2
1.0
1,2-Dichloropropane
78-87-5
1.0
1,3,5-Trimethylbenzene
108-67-8
1.0
1,3-Dichlorobenzene
541-73-1
1.0
1,3-Dichloropropane
142-28-9
1.0
1,4-Dichlorobenzene
106-46-7
1.0
2,2-Dichloropropane
594-20-7
1.0
2-Chlorotoluene
95-49-8
1.0
4-Chlorotoluene
106-43-4
1.0
Acetone
67-64-1
20
Allyl chloride
107-05-1
1.0
Benzene
71-43-2
1.0
Bromobenzene
108-86-1
1.0
Bromochloromethane
74-97-5
1.0
Bromodichloromethane
75-27-4
1.0
Bromoform
75-25-2
1.0
Bromomethane
74-83-9
2.0
n-Butylbenzene
104-51-8
1.0
sec-Butylbenzene
135-98-8
1.0
tert-Butylbenzene
98-06-6
1.0
Carbon tetrachloride
56-23-5
1.0
Chlorobenzene
108-90-7
1.0
Chlorodibromomethane
124-48-1
1.0
Chloroethane
75-00-3
1.0
Chloroform
67-66-3
1.0
Page 18 of 20
May 2024 | c-prp4-05
Chemical name
CAS #
Report level (µg/L)
Chloromethane
74-87-3
1.0
cis-1,2-Dichloroethene
156-59-2
1.0
cis-1,3-Dichloropropene
10061-01-5
1.0
Dibromomethane
74-95-3
1.0
Dichlorodifluoromethane
75-71-8
1.0
Dichlorofluoromethane
75-43-4
1.0
Ethylbenzene
100-41-4
1.0
Ethyl ether
60-29-7
1.0
Hexachlorobutadiene
87-68-3
1.0
Isopropylbenzene
98-82-8
1.0
p-Isopropyltoluene
99-87-6
1.0
Methyl ethyl ketone (2-butanone)
78-93-3
10
Methyl isobutyl ketone (4-methyl-2-pentanone)
108-10-1
5.0
Methyl tertiary-butyl ether
1634-04-4
2.0
Methylene chloride
75-09-2
2.0
Naphthalene
91-20-3
1.0
n-Propylbenzene
103-65-1
1.0
Styrene
100-42-5
1.0
Tetrachloroethene
127-18-4
1.0
Tetrahydrofuran
109-99-9
10
Toluene
108-88-3
1.0
trans-1,2-Dichloroethene
156-60-5
1.0
trans-1,3-Dichloropropene
10061-02-6
1.0
Trichloroethene
79-01-6
1.0
Trichlorofluoromethane
75-69-4
1.0
Vinyl chloride
75-01-4
1.0
m&p-Xylene
179601-23-1
1.0
o-Xylene
95-47-6
1.0
Page 19 of 20
May 2024 | c-prp4-05
Appendix B: Target analyte list for petroleum volatile
organic compounds
Chemical name
CAS #
Report level (µg/L)
1,2,4-Trimethylbenzene
95-63-6
1.0
1,3,5-Trimethylbenzene
108-67-8
1.0
Benzene
71-43-2
1.0
Ethylbenzene
100-41-4
1.0
Methyl tertiary-butyl ether
1634-04-4
2.0
Naphthalene
91-20-3
1.0
Toluene
108-88-3
1.0
m&p-Xylene
179601-23-1
1.0
o-Xylene
95-47-6
1.0
Appendix C: Target analyte list for polychlorinated biphenyls
Chemical name
CAS #
Report level (µg/L)
Aroclor 1016
12674-11-2
0.25
Aroclor 1221
11104-28-2
0.50
Aroclor 1232
11141-16-5
0.25
Aroclor 1242
53469-21-9
0.25
Aroclor 1248
12672-29-6
0.25
Aroclor 1254
11097-69-1
0.25
Aroclor 1260
11096-82-5
0.25
Appendix D: Target analyte list for polycyclic aromatic
hydrocarbons
Chemical name
CAS #
Report level (µg/L)
Acenaphthene
83-32-9
5
Acenaphthylene
208-96-8
5
Anthracene
120-12-7
5
Benzo(a)anthracene
56-55-3
5
Benzo(b)fluoranthene
205-99-2
5
Benzo(k)fluoranthene
207-08-9
5
Benzo(g,h,i)perylene
191-24-2
5
Benzo(a)pyrene
50-32-8
5
Chrysene
218-01-9
5
Dibenz(a,h)anthracene
53-70-3
5
Fluoranthene
206-44-0
5
Fluorene
86-73-7
5
Indeno(1,2,3-cd)pyrene
193-39-5
5
2-Methylnaphthalene
91-57-6
5
Page 20 of 20
May 2024 | c-prp4-05
Chemical name
CAS #
Report level (µg/L)
Naphthalene
91-20-3
5
Phenanthrene
85-01-8
5
Pyrene
129-00-0
5
1-Methylnaphthalene
90-12-0
5
Appendix E: Target analyte list for 1,2-dibromoethane and
1,2-dibromo-3-chloropropane
Chemical name
CAS #
Report level (µg/L)
1,2-Dibromo-3-chloropropane
96-12-8
0.05
1,2-Dibromoethane
106-93-4
0.05
Figure 1. Monitoring well VOC sampling requirements.
