DERR-2025-000129

December 10, 2024

Ms. Leigh Anderson
Utah Department of Environmental Quality
Division of Environmental Response and Remediation
195 North 1950 West
Salt Lake City, Utah 84116
P.O. Box 144840
Salt Lake City, Utah 84114-4840

RE: Further Site Characterization Work Plan – REVISED
Reading Truck
330 West Center Street
North Salt Lake, Utah 84054
Voluntary Cleanup Program #C120
August Mack Project Number JX2830.350

Dear Ms. Anderson:

August Mack Environmental, Inc. (August Mack), on behalf of Poindexter Properties,
LLC (Poindexter), is submitting this Further Site Characterization (FSC) Work Plan (WP)
for the above referenced Site. The FSC WP is being prepared in response to the Utah
Department of Environmental Quality (UDEQ) technical comment letter dated August
23, 2024(Appendix A).

August Mack trusts that this document meets with your approval. Please feel free to
contact us should you have any questions or comments regarding this submittal.

Sincerely,

Steven Faulk Bryant Hoffer, CHMM, LPG
Project Manager Senior Manager/ Geologist

FURTHER SITE CHARACTERIZATION WORK PLAN
READING TRUCK
330 WEST CENTER STREET
NORTH SALT LAKE, UTAH
VOLUNTARY CLEANUP PROGRAM #C120

AME PROJECT #: JX2830.350

PREPARED FOR:

Ms. Leigh Anderson
Utah Department of Environmental Quality
Division of Environmental Response and Remediation
Voluntary Cleanup Program
195 North 1950 West
Salt Lake City, Utah 84116
P.O. Box 144840
Salt Lake City, Utah 84114-4840

PREPARED BY:

August Mack Environmental, Inc.
1302 North Meridian Street, Suite 300
Indianapolis, Indiana 46202

ISSUE DATE:

September 9, 2024

TABLE OF CONTENTS
1.0 INTRODUCTION........................................................................................................... 2
1.1 Site Description and Background Information ........................................................ 2
1.2 Site Physical Settings ................................................................................................... 3
1.3 Objectives ...................................................................................................................... 3
1.4 Site-Specific Potential Contaminants (PCs) .............................................................. 3
2.0 SOIL INVESTIGATION ............................................................................................... 4
3.0 GROUNDWATER INVESTIGATION ....................................................................... 6
3.1 Monitoring Well Installation ...................................................................................... 6
3.2 Groundwater Sampling .............................................................................................. 6
4.0 VAPOR INTRUSION INVESTIGATION ................................................................. 8
4.1 Sub-slab Soil Gas Sampling ..................................................................................... 8
5.0 FIELD INVESTIGATION AND REPORTING ........................................................ 8
6.0 REFERENCES ................................................................................................................ 10

List of Figures
Figure 1: Proposed Sample Location Map

List of Tables
Table 1: Summary of Sampling Rationale

List of Appendices
Appendix A: UDEQ Technical Comment Letter
Appendix B: Field Procedures

Ms. Leigh Anderson December 10, 2024
2
1.0 INTRODUCTION

On behalf of Poindexter Properties, LLC (Poindexter), August Mack
Environmental, Inc. (August Mack) is submitting this Further Site Characterization (FSC)
Work Plan (WP) to the Utah Department of Environmental Quality (DEQ) Voluntary
Cleanup Program (VCP) for the property located at 330 West Center Street, North Salt
Lake, Utah (Site). The FSC WP presents a plan to further investigate impacts previously
identified at the Site. The information obtained during the investigation will be used to
identify potential source areas, characterize and delineate impacts, further assess
potential vapor intrusion (VI), and evaluate if there are any remediation needs.

1.1 Site Description and Background Information
The Site is located in the City of North Salt Lake in Davis County, Utah. The Site is
comprised of one 7.41-acre parcel which is developed with one approximately 25,000-
square foot commercial building which is currently operated by Reading Truck, a semi-
truck sales and service facility. The Site has been used for light industrial purposes
involving the repair and modification of tanker trucks which transport and use petroleum
products since the 1990s. The surface area of the Site consists of paved asphalt on the
south portion and gravel parking on the north portion.

August Mack prepared a Phase I Environmental Site Assessment (ESA) dated August 18,
2021, which identified four Recognized Environmental Conditions (RECs) associated
with historical Site operations both on-Site and adjoining properties. In June 2021,
August Mack completed a Phase II Limited Subsurface Investigation (LSI) to evaluate
identified RECs and included the advancement of nine soil borings (SB-1 through SB-9)
across the Site for the purpose of collecting soil and grab groundwater samples.
Laboratory analytical results reported benzo(a)pyrene, arsenic, and chromium in soil at
concentrations above the United States Environmental Protection Agency (U.S. EPA)
2021 Industrial Soil Regional Screening Level (RSL) and dissolved arsenic in groundwater
at concentrations above the U.S. EPA Groundwater Protection Standards (GWPS).

On May 3, 2022, August Mack, on behalf of Poindexter, submitted an application to the
DEQ requesting acceptance into the VCP, which was subsequently granted on June 22,
2022. Poindexter entered into a Voluntary Cleanup Agreement with the DEQ on July 20,
2022.

Ms. Leigh Anderson December 10, 2024
3
August Mack conducted Site characterization activities at the facility in January and
February 2024, which included the advancement of 12 soil borings (SB-201 through SB-
212), collection of eight grab groundwater samples, installation and sampling of four
permanent monitoring wells (MW-1, MW-2, MW-3, and MW-4) and three sub-slab soil
gas (SGss) vapor ports. Several contaminants were reported above applicable GWPSs in
groundwater samples with the highest concentrations reported around MW-2. As such,
additional investigations were determined necessary to further delineate impacts. No
PCs were reported above applicable RSLs in on-Site soils except for arsenic, which was
believed to be a result of elevated background levels. Additional data to support August
Mack’s opinion that arsenic is within background ranges is provided below.

1.2 Site Physical Settings
The site is located approximately 2 miles east of the Jordan river, and 4 miles northwest
of the Bonneville Shoreline Preserve. Previous investigations identified Site-specific
lithology characterized primarily of fine to medium grained sand and clayey sand,
interbedded with silty sand, silty clay, and gravel.

1.3 Objectives
The following objectives have been determined for this FSC WP:
1. Delineate soil and groundwater contamination along southern and eastern
property boundary to below current U.S. EPA RSLs and MCLs;
2. Delineate potential Per- and polyfluoroalkyl substances (PFAS) impacts on the
eastern boundary of the site where it is believed the former landfill existed.
3. Confirm Site-specific groundwater flow direction.
4. Further evaluate the VI exposure pathway within the Site building.

1.4 Site-Specific Potential Contaminants (PCs)
A summary of the sampling rational, including media, depths, and proposed analysis is
presented on Table 1.
Ms. Leigh Anderson December 10, 2024
4
2.0 SOIL INVESTIGATION

August Mack proposes to advance five soil borings to an approximate depth of 15-feet
below grade (ft bg)1 via Geoprobe direct-push sampling techniques to further evaluate
impacts both on-Site and off-Site. The location and rationale for each soil boring is
provided below:
• One soil boring (SB-301) will be advanced to the southeast of SB-9 and converted
into a 2-inch monitoring well (MW-5) at the specific request of UDEQ
representatives to evaluate the potential for a release of contaminants in the area,
including PCBs and PFAS.
• One soil boring (SB-302) will be advanced on the eastern boundary of the site and
converted into a 2-inch permanent monitoring well (MW-6) to delineate
naphthalene and PFAS impacts in groundwater.
• One soil boring (SB-303) will be advanced southeast of SB-208 to delineate PCBs
impacts at SB-208 and PAHs at SB-207.
• One soil boring (SB-304) will be advanced off-Site within the north right-of-way
along West Center Street and converted into a 2-inch permanent monitoring well
(MW-7) to evaluate potential off-Site migration of naphthalene from MW-1 and
MW-2.
• One soil boring (SB-305) will be advanced to the south of SB-3 to delineate
benzo(a)pyrene impacts in the 2-4 foot interval.

Existing and proposed soil boring locations are depicted on Figure 1.2

Prior to initiating any work activities, August Mack will contact Blue Stakes of Utah 811
to clear underground utilities at the Site. Additionally, a private utility locate will be
conducted using ground penetrating radar and electromagnetic survey techniq ues to
clear all boring locations.

Soil samples will be collected continuously and screened in 2-foot sections for lithologic
description and evidence of contamination by headspace analysis using a
photoionization detector. A minimum of one unsaturated soil sample will be collected
per boring to be submitted for laboratory analysis. The soil interval most likely to be
impacted will be collected for VOC analysis using U.S. EPA Field Method 5035. Soil

1 Depth of soil borings are based on observed depth to water encountered during previous investigation.
2 Specific soil boring locations will be dependent upon underground utility locations, current equipment locations, and
daily operations.
Ms. Leigh Anderson December 10, 2024
5
samples will be analyzed for PCs presented in Table 1. August Mack Field procedures
are included in Appendix B.

Soil samples will be collected in laboratory-supplied sample containers, placed on ice,
and submitted to a state certified laboratory. In accordance with the Site-specific Quality
Assurance Project Plan (QAPP), the following quality assurance/quality control
(QA/QC) samples will be collected for laboratory analysis:
• One (1) duplicate;
• One (1) matrix spike/matrix spike duplicate (MS/MSD);
• One (1) equipment blank (EB) per sampling apparatus;
• One (1) trip blank (TB) per cooler containing samples for VOC analysis; and
• One (1) rinsate blank (RB) per batch of deionized water.
Ms. Leigh Anderson December 10, 2024
6
3.0 GROUNDWATER INVESTIGATION

August Mack proposes to install three permanent monitoring wells to further evaluate
groundwater conditions both on-Site and off-Site. Details are provided below.

3.1 Monitoring Well Installation
Three of the five proposed boring locations (SB-301, SB-302, and SB-304) will be converted
into 2-inch permanent monitoring wells (MW-5 through MW-7) for the purpose of
collecting representative groundwater samples using general low-flow sampling
techniques. Permanent monitoring wells will be constructed from Schedule 40 polyvinyl
chloride (PVC) with a 10-foot machine slotted screen installed using hollow-stem auger
equipment. Proposed well screens will bisect the water table present at the Site and be
completed with flush-mounted or pro-grade steel protective covers surrounded by
concrete pads.

Following installation, the monitoring wells will be developed with a submersible pump
and surge block prior to being surveyed by a professional licensed surveyor. Proposed
well installation procedures are included in Appendix B. Proposed monitoring well
locations are depicted on Figure 1.

3.2 Groundwater Sampling
Following installation and development activities, the entire monitoring well network
(MW-1 through MW-7) will be gauged and sampled via low-flow sampling techniques,
in accordance with August Mack field procedures. Depth to water measurements will be
collected from the entire monitoring well network and used to calculate potentiometric
surface contours across the Site to determine the Site-specific groundwater flow direction
at the time of sampling.
In order to address sensitivity concerns with hexavalent chromium (CrVI) raised by
UDEQ, August Mack will include sampling of CrVI in all groundwater samples. The
results of this sampling will be compared to applicable screening levels and provided in
tabulated form in the upcoming report.

One groundwater sample will be collected from each of the monitoring wells for analysis
of PCs presented in Table 1. In addition, the following QA/QC samples will be collected:
• One (1) duplicate;
• One (1) matrix spike/matrix spike duplicate (MS/MSD);
Ms. Leigh Anderson December 10, 2024
7
• One (1) equipment blank per sampling apparatus;
• One (1) trip blank per cooler containing samples for VOC analysis; and
• One (1) rinsate blank per batch of deionized water will be submitted to the
laboratory.
Ms. Leigh Anderson December 10, 2024
8
4.0 VAPOR INTRUSION INVESTIGATION

4.1 Sub-slab Soil Gas Sampling
To further evaluate potential VI within the Site building, samples will be collected from
the three previously installed SGss vapor ports (SGss-1 through SGss-3) using 6-liter
stainless steel canisters over an 8-hour period in accordance with August Mack field
procedures. The initial and final vacuum readings will be recorded from the canister and
documented in the field. As a QA/QC measure, primary and secondary leak testing will
be conducted prior to and during proposed sampling activities in accordance with
August Mack field procedures (Appendix B ). In addition, one duplicate sample will be
collected. Samples will be analyzed for PCs listed in Table 1. SGss locations are provided
on Figure 1.

5.0 FIELD INVESTIGATION AND REPORTING

The Further Site Characterization implementation activities will include the
advancement of soil borings, installation and development of groundwater monitoring
wells, and sampling of sub-slab soil gas vapor ports. August Mack will provide the
UDEQ project manager a minimum of 14 days’ notice prior to the commencement of Site
Characterization activities.

The Site Characterization implementation report will include the following:
• Summary of field activities;
• Description of sampling rationale;
• Tabulated analytical data with comparison to current U.S. EPA RSLs, Utah
Groundwater Quality Protection Standards, U.S. EPA Attenuated Vapor Intrusion
Screening Levels (VISLs),hazardous waste limits from 40 CFR 261.24, and
Maximum Contaminant Levels (MCLs);
• Detailed Site Plans depicting sampling locations;
• Soil boring logs and monitoring well construction diagrams;
• Monitoring well purge logs; and
• Findings and conclusions regarding the Site.

In a previous version of the FSC WP, August Mack had proposed a background value for
arsenic that used off-Site data to calculate a Background Threshold Value (BTV). In a
request made by UDEQ, the previous BTV will no longer be used. As such, arsenic levels
will be evaluated during this investigation and a BTV will be calculated and provided
under a separate cover.
Ms. Leigh Anderson December 10, 2024
10
6.0 REFERENCES

August Mack Environmental, Inc., Phase I Environmental Site Assessment, August 18, 2021.

August Mack Environmental, Inc., Phase II Subsurface Investigation, September 2, 2021.

August Mack Environmental, Inc., Site Characterization Report, May 24, 2024.

United States Environmental Protection Agency, Low Stress (low flow) Purging and
Sampling Procedures for the Collection of Groundwater Samples From Monitoring Wells, July
20, 1996, Revised September 19, 2017.

Utah Department of Environmental Quality (DEQ), Semi Service Environmental Assessment
Comments, November 16, 2022.

Utah Department of Environmental Quality (DEQ), Voluntary Cleanup Agreement, July 28,
2022.

FIGURES

TABLES

330 West Center Street
North Salt Lake, Utah
TABLE 1
SAMPLING RATIONALE SUMMARY
UTAH SEMI-SERVICE
August Mack Project No.
JX2830.380
Air
Parameters
Location ID Location Type
VO
C
s
PA
H
s
RC
R
A

8
PC
B
s
PA
H
s
Cr
+
6
RC
R
A

8
(
T
o
t
)
RC
R
A

8
(
D
i
s
)
PF
A
S
PC
B
s
VO
C
s
11 0 11 11 12 6 10 13 13 13 11 5 4 4
MW-1 Existing Monitoring
Well Water ~8-18'NA NA 1 NA NA NA NA 1 1 1 1 0 0 NA 2nd Monitoring Event with PFAS addition
MW-2 Existing Monitoring
Well Water ~6-16'NA NA 1 NA NA NA NA 1 1 1 1 0 0 NA 2nd Monitoring Event with PFAS addition
MW-3 Existing Monitoring
Well Water ~5-15'NA NA 1 NA NA NA NA 1 1 1 1 0 0 NA 2nd Monitoring Event with PFAS addition
MW-4
(MS/MSD)
Existing Monitoring
Well Water ~7-17'NA NA 3 NA NA NA NA 3 3 3 3 0 0 NA 2nd Monitoring Event with PFAS addition, collect MS/MSD (sample in triplicate)
SB-301/MW-5
Soil Boring and
Proposed Monitoring
Well
Soil & Water
2-4'
4-6'
5-15'
2 NA 1 2 2 2 2 1 1 1 1 1 1 NA At the specific request of UDEQ represenatives, including PCBs and PFAS since UDEQs suspects an
unknown release
SB-302/MW-6
Soil Boring and
Proposed Monitoring
Well
Soil & Water
2-4'
4-6'
5-15'
2 NA 1 2 2 2 2 1 1 1 1 1 1 NA At the specific request of UDEQ represenatives, including PCBs and PFAS since UDEQs suspects an
unknown release
SB-304/MW-7
Soil Boring and
Proposed Monitoring
Well
Soil & Water
2-4'
4-6'
5-15'
2 NA 1 2 2 0 2 1 1 1 0 0 NA Delineation of Naphthalene in MW-1
SB-303 Soil Boring Soil & Water
2-4'
4-6'
5-15'
2 NA 1 2 2 0 2 1 1 1 1 0 0 NA Delineation of Naphthalene and B(a)P in SB-207 and PCBs in SB-208
SB-305 Soil Boring Soil 2-4'
4-6'2 NA NA 0 2 NA NA NA NA NA NA NA NA NA Delineation of SB-3, which has b(a)p impacts at 2-4'.
Duplicate
(SB-301)Soil Boring Soil 2-4'1 NA NA 1 1 1 1 0 0 0 0 0 0 NA QC/QC Duplicate of SB-301
Duplicate
(MW-5)
Proposed Monitoring
Well Water 5-15'NA NA 1 0 0 0 0 1 1 1 1 1 1 NA QC/QC Duplicate of MW-5
Trip Blank QA/QC QA/QC NA NA NA NA 1 0 0 0 0 0 0 0 0 0 NA QA/QC Sample for VOCs
Equipment Blank
(EB-1)Soil Boring QA/QC NA NA NA NA 1 1 1 1 0 0 0 0 0 0 NA Collect equipment blank from soil sampling apparatus
Equipment Blank
(EB-2)Monitoring Well QA/QC NA NA NA NA 0 0 0 0 1 1 1 1 1 1 NA Collect equipment blank from low-flow sampling apparatus
Rinsate Blank QA/QC QA/QC NA NA NA NA 0 0 0 0 1 1 1 0 1 0 NA QA/QC sample of laboratory reagent water. Analyze as field blank for PFAS.
SGSS-1 Sub-Slab Soil Gas Vapor NA NA NA NA NA NA NA NA NA NA NA NA NA NA 1 2nd SGSS monitoring event
SGSS-2 Sub-Slab Soil Gas Vapor NA NA NA NA NA NA NA NA NA NA NA NA NA NA 1 2nd SGSS monitoring event
SGSS-3
(+ Duplicate)Sub-Slab Soil Gas Vapor NA NA NA NA NA NA NA NA NA NA NA NA NA NA 2 2nd SGSS monitoring event
Rationale
Subtotals:
Proposed Parameters:
WaterProposed #
of Grab
GW
Samples
Proposed Parameters:
Soil
Media
Sample
Depths
(ft bg)
Proposed #
of Soil
Samples
Proposed #
of MW
Samples
Page 1 of 1

APPENDIX A

UDEQ August 23 2024 Technical Comment Letter

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144840 • Salt Lake City, UT 84114-4840
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah
SPENCER J. COX
Governor
DEIDRE HENDERSON
Lieutenant Governor
Department of
Environmental Quality
Kimberly D. Shelley
Executive Director
DIVISION OF ENVIRONMENTAL
RESPONSE AND REMEDIATION
Brent H. Everett
Director
ERRC-130-24
August 23, 2024
Phil Schull
Poindexter Properties, LLC
600 Travis Street, Suite #400
Houston, Texas 77002
RE: Technical Review Comments - Semi Service Site Characterization Report
North Salt Lake, Davis County, Utah
Dear Mr. Schull:
The Division of Environmental Response and Remediation (DERR) has reviewed the
Site Characterization Report,dated May 24, 2024, for the referenced site. The review was conducted
in accordance with the requirements of the Voluntary Cleanup Program (VCP).
Based on our assessment, the DERR has enclosed technical comments for your review.
Please address these comments and submit a revised Site Characterization Report.
Thank you for your continued participation in the VCP. If you have any questions, please
contact me at [phone].
Sincerely,
Leigh Anderson, Project Manager
Division of Environmental Response and Remediation
KLA/tt
cc: Brian E. Hatch, Director, Davis County Health Department
Jay Clark, Environmental Health Director, Davis County Health Department
Page 2
DERR Review Comments
Site Characterization Report (SCR) Comments – Semi Service VCP Site
General Comments:

1. During prior discussions on the development of the Site Characterization Workplan, it
was agreed that sampling for PFAS constituents would be deferred until appropriate standards
and laboratory methods were established. As discussed during our recent meeting, these
standards have now been established. Given the site’s proximity to a historical landfill, PFAS
sampling is now requested. Please propose additional sampling to address this comment.
2. Since the Site Characterization Report (SCR) recommended further sampling to better
assess the site, it would be acceptable to include the PFAS sampling requested in General
Comment #1 within a single additional workplan. Please submit this revised workplan for
review.
3. Groundwater sample results should be compared to Maximum Contaminant Levels
(MCLs). If no MCL exists, please use the EPA Regional Screening Levels for Tap Water as a
reference.
4. The designations for TB, EB, and RB samples are unclear. If these represent Trip Blank,
Equipment Blank or other QA/QC samples, please clarify this in the report.
5. The Quality Assurance Project Plan (QAPP) indicated that the Sensitivity evaluation for
groundwater samples would be based on comparing the Method Detection Limit to screening
levels. However, the tables in the report use the Reporting Limit instead. Please revise the table
to ensure consistency with the QAPP
Technical Comments:

1. Page 7: Please revise the text that indicates the site is downgradient of the Old North Salt
Lake Landfill. The boundaries of the former landfill are unclear, and it is uncertain whether the
landfill may have extended beneath the site.
2. Figure 3: Please include numeric values for screening levels so that the results can be
compared to those values. If concentrations are below detection limits, please report the
detection limits.
3. Figure 4: Several analytes are reported below detection limits, but these limits are above
screening levels, which could raise concerns regarding quality assurance (Sensitivity). Please
propose a strategy to address this issue, particularly for potential contaminants such as PCBs and
hexavalent chromium.

4. Table 5: The laboratory results include both Heptane and n-Heptane. Please revise the
table to distinguish between these results.

APPENDIX B

August Mack Field Procedures

GEOPROBE® PROCEDURES

Drilling will be performed in accordance with standard United States Environmental
Protection Agency (U.S. EPA) protocols.

Soil borings will be advanced using a Geoprobe® Direct Push Sampling System. Soil
borings will be advanced to the depth required for the investigation. Soil samples will be
collected continuously from each boring location by pushing a 4-foot long
nickel-plated core barrel sampler, recovering an undisturbed soil sample within a
disposable acetate liner inside the core barrel sampler. A new acetate liner will be used
for each sample collected. Upon retrieval, soil samples will be handled with new, clean
nitrile sampling gloves to prevent cross-contamination between samples. All reusable
equipment used to collect the soil samples will be decontaminated with a Liquinox ® (or
equivalent) solution and rinsed with tap water and distilled water between each boring
location.

Upon retrieving the 4-foot sections of soil, the samples will be divided into 2-foot sections.
A representative portion of the soil from each 2-foot section will be immediately placed
in plastic bags with zero head-space and put on ice for possible sample collection. A
separate aliquot from each 2-foot section will be placed into a Ziploc bag and screened in
the field by headspace analysis using a MiniRae® photoionization detector (PID), while
the remaining soil will be lithologically classified and inspected in the field for evidence
of contamination (odors, staining, etc.). The results of headspace analyses, lithological
descriptions, and core retrieval times will all be recorded on boring logs. The soil samples
selected for laboratory analysis will be transferred to clean, labeled sample containers
(provided by the laboratory) and placed immediately back on ice in a cooler for
preservation in the field. Soil samples will be submitted to a state certified laboratory for
analysis.

Non-dedicated equipment used during soil boring activities will be decontaminated
before and after each use with non-phosphate detergent wash, followed by distilled
water rinses to prevent cross-contamination.

MONITORING WELL INSTALLATION PROCEDURES

All drilling and well installations will be performed in accordance with standard United
States Environmental Protection Agency (U.S. EPA) protocols.
Upon completion of the Geoprobe® soil borings, select borings will be converted into
permanent monitoring wells using hollow-stem auger drilling technology. Each well will
consist of 2-inch diameter PVC with 10 feet of 0.010-inch machine slotted well screen
threaded to the appropriate length of PVC riser. The screen filter pack will consist of
coarse washed filter sand (#5 sand) installed via gravity pour around the well screen. A
weighted measuring tape will be used to ensure that bridging does not occur during
installation of the filter pack. During installation, the augers will be slowly removed as
the annular space is filled with sand. This process will continue until the filter pack
extends approximately 2-feet above the top of the well screen. The annular space will be
filled with hydrated bentonite chips, installed via gravity pour, to approximately 2 -feet
above the filter pack, creating a bentonite seal. Above the seal, the annular space will be
filled with bentonite chips to approximately 2-feet below ground level. The remaining
annular space will then be filled with sand to approximately 2-inches below the top of
the well casing.

Each well will be finished by installing a flush-mount or pro-grade steel protective cover
surrounded by a 2-foot by 2-foot concrete pad. The riser pipes will be cut approximately
3-inches below the opening of the protective cover and each well will be completed with
a locking well cap.

Following installation, the monitoring wells will be developed to produce water that is
as free as practicable from sediment, drill cuttings, and drilling water via a submersible
pump. Each well will be developed until the water is deemed representative of
groundwater. The wells will be allowed to equilibrate for at least 24-hours prior to
sampling. All drilling materials will be decontaminated between each monitoring well
location and prior to demobilization from the Site.

Decontamination procedures during well installation activities will include pressure-
washing augers that encounter soils with non-phosphate detergent wash, followed by
distilled water rinses. The development pump will also be decontaminated before and
after each use with non-phosphate detergent wash, followed by distilled water rinses to
prevent cross contamination.

GROUNDWATER LEVEL MEASUREMENTS

Water level measurements will be taken from each monitoring well prior to groundwater
sampling. After removing the well cap, sufficient time will be allowed for the water level
to equilibrate with the ambient air pressure. The water level indicator will be
decontaminated before and after each use with a non-phosphate detergent wash,
followed by tap water and distilled water rinses to prevent cross-contamination.
Prior to water level measuring, the existing reference point on the well casing will be
determined (typically the north side of the PVC casing). A water level indicator probe
will be slowly lowered into the well until the sound from the indicator is audible. The
probe will then be slowly pulled out a few inches and dropped back down at smaller
increments until the water level could be determined to within 0.01-feet. The water level
will be measured based on an existing reference point on the well casing. Fo llowing
sampling activities, the total depth of the well will be measured and recorded to the
nearest 0.01-feet by allowing the measuring tape to contact the base of the well.

LOW-FLOW GROUNDWATER SAMPLING

Low-flow sampling will be conducted in general accordance with United States
Environmental Protection Agency (U.S. EPA) low-flow sampling procedures
(U.S. EPA, 1996). Prior to groundwater sample collection, water level measurements will
be collected from each well.
The water quality monitoring equipment will be placed inside the secondary
containment to prevent direct contact between the equipment and site surface.
August Mack will utilize a stainless steel variable speed centrifugal pump or bladder
pump to purge and sample the well. The pump will be decontaminated prior to purging
and sampling using a phosphate-free detergent and triple rinsed using tap water and
deionized water. The pump will be attached to low density polyethylene (LDPE) tubing.
New tubing will be used for each well, and the tubing will be discarded after each use.
For each well, the pump will slowly be lowered into the water column and the
submersible pump intake will be placed at approximately the midpoint of the
groundwater zone within the screened interval.
In accordance with U.S. EPA guidance, flow rates for the well purging and sampling will
be maintained below 1.0 liter/minute (generally within the range of 100 to
400 milliliter/minute) and drawdown of the aquifer will be continually measured to
ensure that it remained less than 4-inches. During the well purging, groundwater
physical and chemical characteristics will be measured using a multi-parameter meter
connected to an in-line flow cell. These characteristics include: turbidity, dissolved
oxygen, temperature, pH, specific conductivity, and oxidation reduction potential.
Once stable conditions are generally achieved, water samples will be obtained using the
low-flow equipment and collected in laboratory supplied sample containers. The purge
water generated during well sampling will be containerized (using 55-gallon steel drum)
and properly labeled pending proper disposal. Following sampling, the well will be
closed and locked.

EQUIPMENT DECONTAMINATION

All equipment that will come in contact with the soil and groundwater will be
decontaminated before and after use with non-phosphate detergent wash, followed by
distilled water rinses to prevent cross-contamination. The hollow stem augers used to
install the wells will be cleaned with a power washer and non-phosphate detergent wash
inside a decontamination pad. All decontamination water generated during the
redevelopment and sampling activities will be containerized in properly labeled
55-gallon drums and stored on Site pending disposal.

LEAK TESTING PROCEDURES

Prior to air sampling, August Mack will conduct leak testing at each SGss sample port to
confirm that the sampling train, sampling equipment, and port will not leak.

Individual sampling trains will be tested for potential leaks using a pump. The pump will
be connected to each sampling train, all ball valves and connections will be closed, and a
vacuum of approximately -15 inches mercury (Hg) will be applied to the sampling train
using the pump. The induced vacuum will be observed for one minute. The leak test
will be rendered successful if the change in vacuum over the observation period is equal
to or less than 0.5-inch Hg.

Each sample port will be leak tested using a helium tracer gas and shroud. A shroud will
be placed over the port and flexible tubing will be connected. This tubing will then be
threaded out of the shroud through an airtight hole. The shroud will be filled with helium
via a port that can be sealed. Using a helium detector for field screening, August Mack
personnel will record the percentage of helium in the shroud. With the port sealed, the
helium detector will be fitted to the tubing that is connected to the sample port. The
helium detector will extract and analyze soil gas from the port. Any detections of helium
indicate a leak is present in the sample port. If a leak is detected, an evaluation will be
completed, adjustments made, and leak tested again. Once the sample port passes the
leak test, sampling will be conducted.

SUB-SLAB SOIL GAS SAMPLING PROCEDURES

To collect the SGss samples, August Mack will use 6-liter laboratory-supplied stainless-
steel Summa® canisters equipped with regulators. Each Summa® canister regulator will
be equipped with a laboratory-supplied air filter to prevent clogging of the canister
opening during sample collection. Prior to sampling the SGss sample ports, a known
volume of ambient air will be purged from the tubing equal to three volumes of the probe
and tubing. Additionally, sampling train and SGss sample port leak tests will be
conducted prior to sampling.

Each canister valve will be opened, and samples will be collected over an 8-hour
timeframe. Start time of each sample, initial vacuum, and canister and regulator serial
numbers will be logged on the field log sheets.

After the sampling period, the final vacuum of each canister and the sample collection
times will be recorded on the field log sheet. The canister valves will be closed, and the
canisters will be properly labeled with pertinent sampling information. The samples will
then be delivered to a state certified laboratory for analysis using chain-of-custody
documentation.