WS-4667_15111_CA_MRP_20230914

SUBSEQUENT MONITORING
REPORT
WHITE ROCK SERVICE STATION (INCIDENT NO. 15111)
11601 NC-86 SOUTH
PROSPECT HILL, CASWELL COUNTY, NORTH CAROLINA
ESP Project No. 23-00200-102

Prepared For:
North Carolina Department of Environmental Quality
Division of Waste Management
1646 Mail Service Center
Raleigh, North Carolina 27699-1646

Prepared By:
ESP Associates, Inc.
P. O. Box 7030
Charlotte, North Carolina 28241

September 14, 2023
ESP Associates, Inc.
P.O. Box 7030 • Charlotte, NC 28241
1.800.960.7317 • NC: 704.583.4949, fax [phone] • SC: 803.802.2440, fax [phone]
www.espassociates.com
September 14, 2023
Mr. Thomas Chapman
North Carolina Department of Environmental Quality
Division of Waste Management
1646 Mail Service Center
Raleigh, North Carolina 27699-1646
Email: [e-mail]
Reference:SUBSEQUENT MONITORING REPORT
White Rock Service Station (Incident #15111)
11601 NC-86 South
Prospect Hill, Caswell County, North Carolina
ESP Project No. 23-00200-102
Dear Mr. Chapman:
ESP Associates, Inc. (ESP) is pleased to present this Subsequent Monitoring Report documenting
activities performed at the subject site, White Rock Service Station, in accordance with North
Carolina Department of Environmental Quality (NCDEQ), Task Authorization No. 1, approved on
May 19, 2023. The subject site is located at 11601 NC-86 South in Prospect Hill, Caswell County,
North Carolina.
We appreciate the opportunity to provide environmental services on this project. If you should have
any questions, please do not hesitate to contact us at [phone].
Sincerely,
ESP Associates, Inc.
Matthew R. Craig Christopher J. Ward, PG, RSM
Project Manager Senior Geologist
Attachment – Subsequent Monitoring Report
TABLE OF CONTENTS
Section Page
SITE INFORMATION .....................................................................................................................i
EXECUTIVE SUMMARY..............................................................................................................iii
1.0 INTRODUCTION ...............................................................................................................1
1.1 SITE SETTING............................................................................................................1
1.2 SITE GEOLOGY AND HYDROGEOLOGY..................................................................1
1.3 SURFACE WATER .....................................................................................................2
1.4 WATER SUPPLY WELLS ...........................................................................................2
2.0 SITE HISTORY...................................................................................................................3
3.0 FIELD ACTIVITIES ...........................................................................................................5
3.1 WATER LEVEL GAUGING ........................................................................................5
3.2 GROUNDWATER SAMPLING....................................................................................6
3.3 FREE PRODUCT EVALUATION ................................................................................6
3.4 WATER SUPPLY WELL SAMPLING..........................................................................7
3.5 FIELD QUALITY CONTROL SAMPLING AND ANALYSIS........................................7
4.0 ANALYTICAL RESULTS...................................................................................................8
5.0 CONCLUSIONS AND RECOMMENDATIONS..................................................................9
6.0 REFERENCES..................................................................................................................10
FIGURES
Figure 1 USGS Topographic Site Location Map
Figure 2 Site Map
Figure 3 Groundwater Elevation Map
Figure 4 Groundwater Results Map
Figure 5 Benzene Isoconcentration Map
Figure 6 Water Supply Well Radius Map
TABLES
Table 1 Water Supply Well Information
Table 2 Monitoring Well Construction and Groundwater Elevation Data
Table 3 Summary of Groundwater Analytical Results
APPENDICES
Appendix A Tables of Previous Groundwater Elevations and Analytical Results
Appendix B Photographs and Field Documentation
Appendix C Laboratory Data Reports
Subsequent Monitoring Report ESP Project No. 23-00200-102
White Rock Service Station (Incident #15111) September 14, 2023
i
SITE INFORMATION
Date of Report:September 14, 2023
NCDEQ Incident No:15111
NCDEQ UST No.:WS-4667
Site Name:White Rock Service Station
Site Location:11601 NC-86 South
Prospect Hill, Caswell County, NC 27314
Latitude:N 36.298330
Longitude:W -79.214860
UST Owner/ Operator:Foust Oil Company, Inc. (Defunct)
Current Property
Owner:Nancy G. Hooper
752 Atwater Road
Burlington, NC 27217
[phone]
Current Property
Occupant:Currently Unoccupied
Consultant:ESP Associates, Inc.
P.O. Box 7030
Charlotte, NC 28241
[phone]
Laboratory:Pace Analytical Services, LLC
NCDEQ No. 5342
9800 Kincey Avenue
Huntersville, NC 28028
[phone]
Release Information:Release Discovery Date: June 6, 1989.
Estimate Quantity: Unknown.
Cause of Release: Corrosion of USTs and ASTs.
Source of Release: Two 1,000-gallon gasoline USTs, two 1,000-gallon
orphan USTs, one 550-gallon kerosene UST, and one 550-gallon diesel
UST.
Currently Active Tanks: None. Tanks Removed in June 1989.
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I, Christopher J. Ward, a Professional Geologist for ESP Associates, Inc., do certify that the
information contained in this report is correct and accurate to the best of my knowledge.
ESP Associates, Inc. is licensed to practice both geology and engineering in North Carolina. ESP
Associates, Inc.’ certification numbers are: Geology: C-556 / Engineering: F-1407
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iii
EXECUTIVE SUMMARY
This executive summary section provides an abbreviated reporting of our Site observations and
findings. Refer to the main text and appendices for a complete reporting of our observations and
findings.
ESP Associates, Inc. (ESP) has completed a Subsequent Monitoring Report documenting
assessment activity performed at the White Rock Service Station site (Incident No. 15111). The
site is an undeveloped site (Tax Parcel PIN. 0117003) located at 11601 NC Highway 86 South,
Prospect Hill, Caswell County, North Carolina. This report was completed to summarize the findings
of assessment activities performed on July 11, 2023, in accordance with North Carolina Department
of Environmental Quality (NCDEQ), Task Authorization No. 1, approved on May 19, 2023.
The work was performed as part of the State Lead Contract #N70522-D between NCDEQ and ESP.
This report was prepared in general accordance with the 15A NCAC 2L .0115 regulations and the
NCDEQ Underground Storage Tank (UST) Section Guidelines for Assessment and Corrective Action
for UST Releases, January 2021, under the supervision of Christopher J. Ward, North Carolina
registered professional geologist (North Carolina License No. 1600).
On July 11, 2023, ESP performed the following field activities:
Gauged static water levels in site monitoring wells MW-1 through MW-13. Although
planned, ESP was unable to gauge MW-7 or MW-9 as they were lost during previous site
events. Mapped locations of the wells indicate they may have been lost during re-paving
and graveling of the lot. MW-10 was also unable to be gauged as the well was part of a
sealed system of pipes and could not be accessed;
Collected groundwater samples from monitoring wells MW-1 through MW-13, including
a field duplicate of MW-12. Although planned, ESP was unable to sample MW-7, MW-9,
and MW-10, for the reasons listed above;
Replaced Oxygen Release Compound (ORC) Socks in MW-11, MW-12, and MW-13;
Obtained water supply well sampling agreements from water supply wells WSW-1 and
WSW-2 property owners; and
Collected water supply well samples from WSW-1 and WSW-2.
Collected water samples were analyzed for volatile organic compounds (VOCs) for comparison to
both North Carolina Groundwater Quality Standards 15A NCAC 2L .0202 (2L Standards) and Gross
Contaminant Levels (GCLs).
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Based on results of the above field activities and previous reporting, ESP concludes the following:
 Two water supply wells (WSW-1 and WSW-2) are located within 500 feet of the source
area and two water supply wells (WSW-3 and WSW-4) are located within 1,000 feet of the
source area;
Municipal water is reportedly not available in the area surrounding the site;
Static water level depths ranged from 24.35 to 27.75 ft bTOC;
Shallow groundwater flow at the site was estimated to be radial from the source area;
Free product was not detected in any sampled monitoring well;
No Analytes were detected above the GCL in any monitoring well or supply well samples;
All analytes were below MDLs in MW-1 through 6, MW-8, WSW-1, and WSW-2;
All analytes were equal to or less than 2L standards in MW-11 and MW-13 except for 1,2-
dichloroethane in MW-13;
Benzene and 1,2-dichloroethane were detected above 2L standards in MW-12;
1,2-dichloroethane was detected above its 2L standard in MW-13; and
ORC Socks were replaced in MW-11, MW-12, and MW-13.
Contaminant concentrations at the site have been steadily decreasing since 2020 with significant
decreases in contaminant concentrations since June 1, 2021 sampling event. Groundwater
concentrations in MW-12 and MW-13 have remained above 2L standards while all analytes
continue to be below MDLs in WSW-1 and WSW-2.
Based on the above results, ESP offers the following recommendations:
Continue to sample site monitoring wells and water supply wells WSW-1 and WSW-2 on
a semiannual basis to further understand concentration trends with the goals of obtaining
below 2L standard concentrations in all site wells;
Continue to maintain ORC socks in MW-11, MW-12, and MW-13 to further reduce
constituent concentrations on site; and
Repair well vaults for MW-1 and MW-2 to make them water proof and replace the well
caps.
Subsequent Monitoring Report ESP Project No. 23-00200-102
White Rock Service Station (Incident #15111) September 14, 2023
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1.0 INTRODUCTION
1.1 Site Setting
The White Rock Service Station site (Tax Parcel ID. 0117003) is located at 11601 NC-86 Highway
South in Prospect Hill, Caswell County, North Carolina (see Figures 1 and 2). The site is presently
unoccupied, containing a shed with a groundwater recovery system, which was not in operation at the
time of our site visit. The site formerly operated as a gasoline and diesel fuel storage and dispensing
facility owned by Exxon. Prior to its removal on June 1989, the underground storage tank (UST)
network consisted of two 1,000-gallon gasoline USTs, one 550-gallon kerosene UST, and one 550-
gallon diesel UST. During the excavation of the system in 1989, two additional 1,000-gallon USTs
of unknown contents were also discovered and removed.
1.2 Site Geology and Hydrogeology
Consideration of surface and subsurface drainage and geology are of interest since they provide
an indication of the direction that contamination, if present on-site or off-site, could be transported.
The site is located within the Piedmont Physiographic Province. The Piedmont Physiographic
Province generally consists of low to medium elevation, rounded hills, and long rolling northeast
to southwest trending ridges with incised creeks and river channels. Rock at the site is described
as metamorphosed granitic rock, locally comprised of hornblende. In-place chemical and physical
weathering of parent rocks typically form residual soils in the Piedmont region. Weathering is
facilitated by the presence of fractures, joints, and less resistant minerals in the rock. In areas not
altered by erosion, alluvial deposition or the activities of man, the typical residual soil profile
consists of clay-rich unconsolidated materials at the surface, transitioning to sandy silts and silty
sands at depth. Typically, the boundary between soil and rock is not sharply defined. This
transitional zone is termed “partially weathered rock” or saprolite. Information obtained from the
Web Soil Survey for Caswell County depicts soils on the site as Louisburg coarse sandy loam, 2
to 6 percent slopes (LoB) and Louisburg coarse sandy loam, 10 to 15 percent slopes (LoD).
In the Piedmont, groundwater generally occurs in pore spaces within soils and in the structural
features present in the underlying rock (i.e., joints, fractures, and faults). Recharge to the water
table is primarily by precipitation infiltrating the surficial soils and percolating downward under
the influence of gravity to the water table. Typically, the water table is not a level surface, but a
subdued reflection of the land surface. The depth to the water table is not consistent and is
dependent upon several factors that include the amount of rainfall, permeability of the soil, the
extent of fracturing in the underlying rock and the influences of groundwater pumping.
The direction and movement of groundwater through soil is generally dependent on soil type, the
presence of relict structures, and the textures of the underlying rock. Fractures, faults, folds, and
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foliation planes affect the migration of groundwater in rock. No major geologic features (faults,
etc.) are present at or near the site. Groundwater typically flows in directions parallel to the ground
surface and under the influence of gravity, migrates to discharge points such as surface water
features, the toes of slopes or natural springs. Fluctuations in the depth of the water table can be
expected depending on variations in precipitation, surface water run-off and other factors.
Normally, the highest levels of the water table occur in late winter and spring and the lowest levels
occur in the late summer and fall. Based on historical data and the July 11, 2023, water level
measurements, shallow groundwater flow at the site was estimated to be radial from the source
area.
1.3 Surface Water
A small stream and pond are located approximately 700 feet southwest of the site while a small pond
is located approximately 700 ft west of the site (see Figures 1 and 6). The stream serves as a tributary
for Lunch Creek. No other surface water features are located within 1,000 feet of the site.
1.4 Water Supply Wells
Based on previous receptor surveys conducted by others, four water supply wells have been
identified within a 1,000 ft radius of the site (see Table 1 and Figure 6). Two of the water supply
wells (WSW-1 and WSW-2) are located within 500 feet of the source area and two water supply
wells (WSW-3 and WSW-4) are located within 1,000 feet of the source area. Municipal water is
reportedly not available in the area surrounding the site
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2.0 SITE HISTORY
The following description of historical site activities was obtained from a report titled “Annual
Monitoring Report, White Rock Service Station” dated July 29, 2022, by Terracon Consultants
Inc. (Terracon).
In June 1989, the entire UST network present on site was closed in place and removed.
The network consisted of two 1,000-gallon gasoline USTs, one 550-gallon kerosene
UST, and one 550-gallon diesel UST. During this excavation, two additional 1,000-
gallon orphan USTs of unknown contents were discovered and removed. Several holes
were discovered in these USTs upon excavation, and an unknown amount of petroleum
impacted soil was subsequently removed.
On April 27, 1994, water samples from water supply well WSW-1 revealed petroleum
constituents above 2L standards.
On February 16, 1995, Turner Environmental Consultants (TEC) mobilized to advance
several soil borings around each former tank basin and the former dispenser station. The
soil samples collected from this mobilization did not indicate any constituents above
MDLs.
Between December 5 and 6, 1994, TEC advanced an additional 17 soil borings
throughout the site. Soil samples were collected from each bore, along with a water
supply well sample from WSW-1. Total Petroleum Hydrocarbons-Diesel Range
Organics (TPH-DRO) analysis indicated several diesel range organics in exceedance of
the NCDEQ Action Levels. VOC analysis of the water supply well sample indicated the
presence of benzene above its 2L standard.
On December 3, 1996, TEC conducted a Comprehensive Site Assessment (CSA), and
installed thirteen monitoring wells throughout the site. Each well was sampled following
its installation, for VOC contaminants. Laboratory analysis indicated benzene
concentrations above its GCL in MW-1, MW-2, and MW-3. Soil borings were also
installed and sampled for constituents. TPH-DRO analysis indicated diesel range
organics above NCDEQ Action Levels.
Between 1997 and 1999, Omega Environmental Services (Omega) installed four
recovery wells, RW-1, RW-2, RW-3, and RW-4 on site. Omega also performed
Aggressive Fluid Vapor Recovery (AFVR) on MW-1 through MW-11.
On March 18, 2001, Omega mobilized to install a dual-phase extraction remediation
system on site.
Groundwater sampling events continued to be performed on site between 2008 and 2019
by Paragon Environmental Consultants (Paragon). These events showed a steady
decrease of benzene concentrations throughout the site from 2007 to 2019. Except for
MW-11 through MW-13, constituents were not detected above MDLs in any monitoring
well or recovery well from 2009 to 2019.
In August 2020, Terracon mobilized to perform a sampling event of monitoring wells
MW-4, MW-5, MW-12, MW-13, and RW-2. Water supply wells WSW-1 and WSW-2
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were also sampled. Only MW-12 and MW-13 contained petroleum constituents above
2L standards. A receptor survey was also carried out during this event. Terracon
identified ten water supply wells within 1,500 feet of the site. WSW-1 and WSW-2 are
located within 500 feet of the site, while WSW-3 and WSW-4 are located within 1,000
feet of the site.
Between June 1 and 2, 2022, Terracon mobilized to conduct a groundwater sampling
event on monitoring wells MW-1 through MW-13, recovery wells RW-1 through RW-
4, and water supply wells WSW-1 and WSW-2. Terracon had also performed an
inspection on the on-site dual-phase extraction remediation system which had at that
point fallen to disuse.
Historical groundwater elevations and analytical results are provided in Appendix A.
Subsequent Monitoring Report ESP Project No. 23-00200-102
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3.0 FIELD ACTIVITIES
On July 11, 2023, ESP performed the following field activities:
Gauged static water levels in site monitoring wells MW-1 through MW-13. Although
planned, ESP was unable to gauge MW-7 or MW-9 as they were lost during previous site
events. Mapped locations of the wells indicate they may have been lost during re-paving
and graveling of the lot. MW-10 was also unable to be gauged as the well was part of a
sealed system of pipes and could not be accessed;
Collected groundwater samples from monitoring wells MW-1 through MW-13, including
a field duplicate of MW-12. Although planned, ESP was unable to sample MW-7, MW-9,
and MW-10, for the reasons listed above;
Replaced Oxygen Release Compound (ORC) Socks in MW-11, MW-12, and MW-13;
Obtained water supply well sampling agreements from water supply wells WSW-1 and
WSW-2 property owners; and
Collected water supply well samples from WSW-1 and WSW-2.
Sample locations are depicted on Figure 2. Field logbook entries along with water level survey,
groundwater sampling, and field instrument calibration forms were completed in the field to
document site activities (see Appendix B). Photographs are also provided in Appendix B. Details
of field activities are provided below.
3.1 Water Level Gauging
On July 11, 2023, prior to purging or collecting groundwater samples, depth to groundwater from
the top of casing (TOC) within each monitoring well was measured and recorded using a
decontaminated electronic water level meter. The water level measurements were collected by first
removing covers and plunger caps from all site monitoring wells and allowing water within the
wells to stabilize. The electronic water level meter probe was then lowered into the well and the
depth to water measured relative to the well’s TOC.
As noted on Table 2, static water level depths ranged from 24.35 to 27.75 ft below top of casing
(ft bTOC). It should be noted that the well vaults for MW-1 and MW-2 were full of rain water
when ESP arrived to gauge and sample site monitoring wells. The day prior to the
gauging/sampling event, heavy rainfall occurred within the area. No well caps were found for
either MW-1 and MW-2 and the wells appeared to be filled with rainwater as water levels were at
or close to the TOC. Based on this, water levels for these two wells were not noted on Table 2 or
used in the preparation of Figure 3. Groundwater elevations, based off TOC elevations obtained
by others using a VRS device in June 2022, depict a shallow groundwater flow at the site to be
radial from the source area (see Figure 3).
Subsequent Monitoring Report ESP Project No. 23-00200-102
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3.2 Groundwater Sampling
On July 11, 2023, monitoring wells MW-1 through MW-6, MW-8, MW-11, MW-12, and MW-13
were sampled for VOC concentrations. Although planned, ESP was unable to sample MW-7 or
MW-9 as they were lost during previous site events. Mapped locations of the wells indicate they
may have been lost during re-paving and graveling of the lot. Also, MW-10 was also unable to be
sampled as the well was part of a sealed system of remedial system pipes and could not be
accessed.
Groundwater samples were collected using dedicated and disposable polyvinyl chloride (PVC)
bailers (1.5” x 3’) attached to braided nylon rope. Prior to groundwater sample collection, each
well was purged using the bailer. During purging, water quality parameters including pH,
conductivity, temperature, and turbidity were measured using calibrated field water quality
instruments. Readings were taken at the start of purging and periodically until a minimum of three
well volumes were removed from the well or water quality parameters stabilized. Following
purging, a groundwater sample for laboratory analysis was collected from the well using the bailer.
The water quality parameters were recorded on groundwater sampling forms along with time,
water level depth, and cumulative volume of water purged (see groundwater sampling forms in
Appendix B).
Due to the apparent presence of surface water within MW-1 and MW-2, approximately 19 gallons
of water was purged from each well to attempt to remove some of the surface water that likely
infiltrated into the well (i.e., to obtain more accurate samples).
Groundwater samples were collected following Guidelines for Sampling by the Underground
Storage Tank Section, Division of Waste Management, North Carolina Department of
Environmental Quality (NCDEQ, 2022). Groundwater samples were placed in laboratory-
prepared vials preserved with hydrochloric acid (HCl), labeled, and stored on ice in a cooler for
subsequent delivery under standard chain-of-custody (COC) procedures to Pace Analytical (Pace),
a North Carolina-certified laboratory, located in Huntersville, North Carolina, for analysis. The
groundwater samples were analyzed for VOCs by EPA Method 6200B including MTBE, ethylene
dibromide (EDB), and isopropyl ether (IPE).
3.3 Free Product Evaluation
During the July 11, 2023, event, no free product was measured or observed in any of the sampled
wells.
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3.4 Water Supply Well Sampling
The access agreement for water supply well WSW-2 was obtained via mail prior to the July 11,
2023 sampling event. The access agreement for WSW-1 was obtained in person during the July
11, 2023 sampling event. Both access agreements are provided in Appendix B.
On July 11, 2023, groundwater samples were collected from water supply wells WSW-1 and
WSW-2. WSWs were sampled by locating a spigot as close to the supply well head as possible.
The spigot was turned on and allowed to purge for at least 15 minutes. Following the purge, flow
was reduced, and samples were collected directly into laboratory-preserved vial preserved with
HCL, labeled, and stored on ice in a cooler for subsequent delivery under standard COC procedures
to Pace for analysis of VOCs by EPA Method 6200B including MTBE, EDB and IPE.
3.5 Field Quality Control Sampling and Analysis
A field duplicate groundwater sample was collected on July 11, 2023, from MW-12 and analyzed
for VOCs by EPA Method 6200B including MTBE, EDB, and IPE to assess variance between
collected samples.
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4.0 ANALYTICAL RESULTS
Results of the laboratory analysis of groundwater samples from monitoring wells MW-1 through
MW-6, MW-8, MW-11, MW-12, and MW-13, plus duplicate along with water supply wells
WSW-1 and WSW-2, are tabulated in Table 3. The analytical results are compared to both 2L
standards and GCLs. The Pace laboratory analytical report is provided in Appendix C.
No analytes were detected at concentrations exceeding their respective GCLs; however, various
analytes were detected at concentrations greater than their respective 2L standards in MW-11,
MW-12, and MW-13. No analytes were detected above 2L standards in the remaining monitoring
wells, or either water supply well (see Table 3 and Figures 4 and 5). A summary of the analytical
results is as follows:
MW-1 through 6, MW-8 - all analytes were below MDLs;
MW-11 and MW-13 - all analytes were equal to or less than 2L standards except for 1,2-
dichloroethane in MW-13;
In MW-12 - benzene (35.4 µg/L) and 1,2-dichloroethane (0.98 µg/L) were both detected
above their respective 2L standards;
In MW-13 - 1,2-dichloroethane (0.65 µg/L) was detected above its 2L standard; and
WSW-1 and WSW-2 - all analytes were below MDLs.
The general trend in groundwater contaminant concentrations at the site have been steadily
decreasing since 2020 with significant decreases in contaminant concentrations since June 1, 2021
sampling event. Groundwater concentrations in MW-12 and MW-13 have remained above 2L
standards. All analytes continue to be below MDLs in WSW-1 and WSW-2.
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5.0 CONCLUSIONS AND RECOMMENDATIONS
Based on results of the above field activities and previous reporting, ESP concludes the following:
 Two water supply wells (WSW-1 and WSW-2) are located within 500 feet of the source
area and two water supply wells (WSW-3 and WSW-4) are located within 1,000 feet of the
source area;
Municipal water is reportedly not available in the area surrounding the site;
Static water level depths ranged from 24.35 to 27.75 ft bTOC;
Shallow groundwater flow at the site was estimated to be radial from the source area;
Free product was not detected in any sampled monitoring well;
No Analytes were detected above the GCL in any monitoring well or supply well samples;
All analytes were below MDLs in MW-1 through 6, MW-8, WSW-1, and WSW-2;
All analytes were equal to or less than 2L standards in MW-11 and MW-13 except for 1,2-
dichloroethane in MW-13;
Benzene and 1,2-dichloroethane were detected above 2L standards in MW-12;
1,2-dichloroethane was detected above its 2L standard in MW-13; and
ORC Socks were replaced in MW-11, MW-12, and MW-13.
Contaminant concentrations at the site have been steadily decreasing since 2020 with significant
decreases in contaminant concentrations since June 1, 2021 sampling event. Groundwater
concentrations in MW-12 and MW-13 have remained above 2L standards while all analytes
continue to be below MDLs in WSW-1 and WSW-2.
Based on the above results, ESP offers the following recommendations:
Continue to sample site monitoring wells and water supply wells WSW-1 and WSW-2 on
a semiannual basis to further understand concentration trends with the goals of obtaining
below 2L standard concentrations in all site wells;
Continue to maintain ORC socks in MW-11, MW-12, and MW-13 to further reduce
constituent concentrations on site; and
Repair well vaults for MW-1 and MW-2 to make them water proof and replace the well
caps.
Subsequent Monitoring Report ESP Project No. 23-00200-102
White Rock Service Station (Incident #15111) September 14, 2023
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6.0 REFERENCES
Caswell County NC WebGIS, https://www.webgis.net/nc/caswell/
1985 Geologic Map of North Carolina, The North Carolina Geological Survey, Phillip M. Brown,
1985.
Guideline for Sampling Underground Storage Tank Section, Division of Waste Management,
North Carolina Division of Environmental Quality, March 7, 2022, Change 4.
Terracon, July 29, 2022, Semi-Annual Monitoring Report: White Rock Service Station (Incident
#15111), Prospect Hill, Caswell County, North Carolina.
Terracon, September 25, 2020, Initial Monitoring Report: White Rock Service Station (Incident
#15111), Prospect Hill, Caswell County, North Carolina
Paragon Environmental Consultants, Inc, April 12, 2017, White Rock Service Station, 11601 NC
Highway 86 Sout, Prospect Hill, Caswell County, North Carolina, Groundwater Incident: 15111,
Facility ID: 0-031180.

FIGURES

0 350 700Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone [phone]
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-102
ET
CWDATE08/04/2023
FIGURE 1USGS TOPOGRAPHIC SITE LOCATION MAPµAs Shown
PROSPECT HILL, NORTH CAROLINA
SITE BOUNDARY
All locations are approximate.
WHITE ROCK SERVICE STATION
LEGEND:
<
<
<<
<
<
<
<
<
<
<
<
<
<<
MW-10
MW-3 MW-9
MW-8
RW-3
MW-7
RW-4
MW-4
RW-1
RW-2
MW-12
MW-2
MW-1MW-5
MW-6
<
MW-13<MW-11
EDWSW-1
ON-SITE RECOVERY SYSTEM
0 20 40Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone [phone]
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-102
ET
CWDATE08/04/2023
FIGURE 2SITE MAPµAs Shown
PROSPECT HILL, NORTH CAROLINA
SITE BOUNDARYMONITORING WELLMONITORING WELL (NOT LOCATED)WATER SUPPLY WELLFORMER UST
All locations are approximate.
WHITE ROCK SERVICE STATION
LEGEND:
<
ED
<
<
<
<<
<
<
<
<
<
<
<
<
<
<<
MW-10
MW-3 MW-9
MW-8
RW-3
MW-7
RW-4
MW-4
RW-1
RW-2
MW-12
MW-2
MW-1MW-5
MW-6
<
MW-13<MW-11
EDWSW-1
ON-SITE RECOVERY SYSTEM
0 20 40Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone [phone]
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-102
ET
CWDATE08/04/2023
FIGURE 3GROUNDWATER ELEVATION MAPJULY 11, 2023µAs Shown
PROSPECT HILL, NORTH CAROLINA
SITE BOUNDARYMONITORING WELLMONITORING WELL (NOT LOCATED)WATER SUPPLY WELLFORMER USTESTIMATED GROUNDWATER ELEVATION CONTOURESTIMATED GROUNDWATER FLOW DIRECTION
All locations are approximate.
WHITE ROCK SERVICE STATION
LEGEND:
<
ED
<
<
<
<<
<
<
<
<
<
<
<
<
<
<<
MW-10
MW-3 MW-9
MW-8
RW-3
MW-7
RW-4
MW-4
RW-1
RW-2
MW-12
MW-2
MW-1MW-5
MW-6
<
MW-13<MW-11
EDWSW-1
0 20 40Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone [phone]
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-102
ET
CWDATE08/04/2023
FIGURE 4GROUNDWATER RESULTS MAPJULY 11, 2023µAs Shown
PROSPECT HILL, NORTH CAROLINA
SITE BOUNDARYMONITORING WELLMONITORING WELL (NOT LOCATED)WATER SUPPLY WELLFORMER UST
All locations are approximate.
WHITE ROCK SERVICE STATION
LEGEND:
<
ED
<
<
<
<<
<
<
<
<
<
<
<
<
<
<<
MW-10
MW-3 MW-9
MW-8
RW-3
MW-7
RW-4
MW-4
RW-1
RW-2
MW-12
MW-2
MW-1MW-5
MW-6
<
MW-13<MW-11
EDWSW-1
0 20 40Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone [phone]
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-102
ET
CWDATE08/04/2023
FIGURE 5BENZENE ISOCONCENTRATION MAPJULY 11, 2023µAs Shown
PROSPECT HILL, NORTH CAROLINA
SITE BOUNDARYMONITORING WELLMONITORING WELL (NOT LOCATED)WATER SUPPLY WELLFORMER USTCONCENTRATION CONTOUR
All locations are approximate.
WHITE ROCK SERVICE STATION
LEGEND:
<
ED
<
ED WSW-1
ED WSW-2
WSW-4ED
ED WSW-3
500-ft
1,000-ft
0 110 220Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone [phone]
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-102
ET
CWDATE08/04/2023
FIGURE 6WATER SUPPLY WELL RADIUS MAPµAs Shown
PROSPECT HILL, NORTH CAROLINA
SITE BOUNDARYWATER SUPPLY WELL RIVERINE WETLAND FRESHWATER PONDFRESHWATER FORESTED/SHRUB WETLAND
All locations are approximate.
WHITE ROCK SERVICE STATION
LEGEND:
ED

TABLES

Table 1
Water Supply Well Information
White Rock Service Station
Prospect Hill, North Carolina
NCDEQ Incident No. 15111
Well No.Property Owner Mailing
Address
Property
Address
Distance from
Source Area
(ft)
Hydraulic
Relationship to
Source Area
Well
Status/Use
Municpal
Water Parcel No.
WSW-1 Prospect Hill Fire
Department
11621 NC
Highway 86 S
Prospect Hill,
NC 27314
11621 NC
Highway 86 S
Prospect Hill,
NC 27314
~140 feet south Upgradient Active No ..0117004
WSW-2 Donald & Juanita
Penny
11535 NC
Highway 86 S
Prospect Hill,
NC 27314
11535 NC
Highway 86 S
Prospect Hill,
NC 27314
~440 feet
northwest Downgradient Active No ..0117071
WSW-3 Harold Jr & Paula
Stone
11741 NC
Highway 86 S
Prospect Hill,
NC 27314
11741 NC
Highway 86 S
Prospect Hill,
NC 27314
~680 feet
southeast Upgradient Active No ..0117005
WSW-4 Dustin Wrenn
4977 Sartin Rd
Burlington, NC
27217
11600 NC
Highway 86 S
Prospect Hill,
NC 27314
~875 feet west Upgradient Active No ..0117010
Notes:
Information obtained from previous monitoring report.
Table 2
Monitoring Well Construction and Groundwater Elevation Data
White Rock Service Station
Prospect Hill, North Carolina
NCDEQ Incident No. 15111
Well
ID
Date
Installed
Screened Interval
(ft BGS) a
Bottom of
Well
(ft BGS) a
Top of Casing
Elevation
(ft) a,b
Date Water
Level Measured
Depth to Water
from Top of
Casing
(ft bTOC)
Groundwater
Elevation
(ft)
Free Product
Thickness
(ft)
8/18/2020 NM NM ---
6/30/2021 20.87 79.13 ---
6/1/2022 NM NM ---
7/11/2023 NM NM ---
8/18/2020 NM NM ---
6/30/2021 13.39 85.92 ---
6/1/2022 NM NM ---
7/11/2023 NM NM ---
8/18/2020 NM NM ---
6/30/2021 21.75 76.62 ---
6/1/2022 24.30 596.36 ---
7/11/2023 24.35 596.31 ---
8/18/2020 22.03 77.88 ---
6/30/2021 22.54 77.37 ---
6/1/2022 24.97 597.67 ---
7/11/2023 25.00 597.64 ---
8/18/2020 24.54 75.82 ---
6/30/2021 24.21 76.15 ---
6/1/2022 26.81 594.82 ---
7/11/2023 26.40 595.23 ---
8/18/2020 20.20 77.60 ---
6/30/2021 20.08 77.72 ---
6/1/2022 23.35 600.84 ---
7/11/2023 27.75 596.44 ---
8/18/2020
6/30/2021
6/1/2022
7/11/2023
8/18/2020 26.69 72.92 ---
6/30/2021 26.57 73.04 ---
6/1/2022 28.40 602.97 ---
7/11/2023 27.60 603.77 ---
8/18/2020
6/30/2021
6/1/2022
7/11/2023
8/18/2020
6/30/2021
6/1/2022
7/11/2023
8/18/2020 NM NM ---
6/30/2021 22.01 78.14 ---
6/1/2022 17.54 604.15 ---
7/11/2023 25.50 596.19 ---
8/18/2020 23.80 78.36 ---
6/30/2021 24.29 77.87 ---
6/1/2022 26.41 597.19 ---
7/11/2023 26.70 596.90 ---
8/18/2020 22.28 79.82 ---
6/30/2021 24.04 78.06 ---
6/1/2022 26.15 597.39 ---
7/11/2023 27.00 596.54 ---
Notes:
a Top of casing elevations, screened intervals, and bottom of well measurements are from previous consultants' monitoring reports.
b Top of casing elevations are based off of an assumed benchmark elevation of 100.00 ft given to MW-1.
-- - no measureable free product
BGS - below ground surface
ft - feet
ft bTOC - feet below TOC
FP - free product
TOC - top of casing
33.0
33.0
33.0
Well Missing
Well Missing
Well Obstructed
40.0
33.0
33.5
34.0
102.16
623.6
631.37
89.93
612.69
100.15
621.69
40.0
20.0-33.0
7/29/1996
7/29/1996
9/17/1996
18.50-33.50 33.5
18.5-33.5
19.5-33.5
19.0-34.0
7/29/1996
7/29/1996
7/29/1996
7/29/1996
7/29/1996
20.0-40.0
20.0-40.0
20.0-40.0
20.0-33.0
19.0-34.0
c Groundwater elevation adjusted for measureable free product by using the following calculation:
(TOC Elevation - Depth to water) + (FP thickness * 0.729), where 0.729 is the specific gravity for automotive gasoline.
MW-1
MW-2
MW-3
MW-4
MW-5
MW-6
MW-7
MW-8
MW-10
MW-11
MW-12
MW-9
2/19/1996
2/19/1996
2/19/1996
621.63
97.80
624.19
MW-13 9/17/1996 18.0-33.0
102.10
623.54
9/17/1996
18.0-33.0
18.0-33.0
97.95
93.87
99.61
40.0
33.5
34.0
33.5
100.00
621.52
99.31
621.7
98.37
620.66
99.91
622.64
100.36
Table 3
Summary of Groundwater Analytical Results
White Rock Service Station
Prospect Hill, North Carolina
NCDEQ Incident No. 15111
(Page 1 of 2)
1 70 70 70 70 0.40 0.60 0.02 70 600 70 20 6 70 600 400 400 500 500 500
5,000 5,900 8,800 14,750 70,000 400 600 50 70,000 80,000 30,500 20,000 6,000 26,100 260,000 28,500 24,100 50,000 50,000 50,000
8/18/20 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR
6/30/21 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.80 <0.40 <0.40
6/1/22 <0.09 <0.16 <0.13 <0.13 <0.11 <0.08 <0.15 <0.13 <0.11 <0.14 <0.11 <0.10 <1.0 <0.10 <0.28 <0.32 <0.10 <0.60 <0.17 <0.43
7/11/23 <0.079 <0.066 <0.085 <0.086 <0.069 <0.11 <0.14 <0.15 <0.072 <0.081 <0.11 <0.053 <0.10 <0.10 <0.09 <0.031 <0.071 <0.234 <0.094 <0.14
8/18/20 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR
6/30/21 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.80 <0.40 <0.40
6/1/22 <0.09 <0.16 <0.13 <0.13 <0.11 <0.08 <0.15 <0.13 <0.11 <0.14 <0.11 <0.10 <1.00 <0.10 <0.28 <0.32 <0.10 <0.60 <0.17 <0.43
7/11/23 <0.079 <0.066 <0.085 <0.086 <0.069 <0.11 <0.14 <0.15 <0.072 <0.081 <0.11 <0.053 <0.10 <0.10 <0.09 <0.031 <0.071 <0.234 <0.094 <0.14
8/18/20 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR
6/30/21 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.80 <0.40 <0.40
6/1/22 <0.09 <0.16 <0.13 <0.13 <0.11 <0.08 <0.15 <0.13 <0.11 <0.14 <0.11 <0.10 <1.00 <0.10 <0.28 <0.32 <0.10 <0.60 <0.17 <0.43
7/11/23 <0.079 <0.066 <0.085 <0.086 <0.069 <0.11 <0.14 <0.15 <0.072 <0.081 <0.11 <0.053 <0.10 <0.10 <0.09 <0.031 <0.071 <0.234 <0.094 <0.14
8/18/20 <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <3.0 <2.0 <1.0
6/30/21 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.80 <0.40 <0.40
6/1/22 <0.09 <0.16 <0.13 <0.13 <0.11 <0.08 <0.15 <0.13 <0.11 <0.14 <0.11 <0.10 <1.00 <0.10 <0.28 <0.32 <0.10 <0.60 <0.17 <0.43
7/11/23 <0.079 <0.066 <0.085 <0.086 <0.069 <0.11 <0.14 <0.15 <0.072 <0.081 <0.11 <0.053 <0.10 <0.10 <0.09 <0.031 <0.071 <0.234 <0.094 <0.14
8/18/20 <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <3.0 <2.0 <1.0
6/30/21 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.80 <0.40 <0.40
6/1/22 <0.09 <0.16 <0.13 <0.13 <0.11 <0.08 <0.15 <0.13 <0.11 <0.14 <0.11 <0.10 <1.00 <0.10 <0.28 <0.32 <0.10 <0.60 <0.17 <0.43
7/11/23 <0.079 <0.066 <0.085 <0.086 <0.069 <0.11 <0.14 <0.15 <0.072 <0.081 <0.11 <0.053 <0.10 <0.10 <0.09 <0.031 <0.071 <0.234 <0.094 <0.14
8/18/20 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR
6/30/21 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.80 <0.40 <0.40
6/1/22 <0.09 <0.16 <0.13 <0.13 <0.11 <0.08 <0.15 <0.13 <0.11 <0.14 <0.11 <0.10 <1.00 <0.10 <0.28 <0.32 <0.10 <0.60 <0.17 <0.43
7/11/23 <0.079 <0.066 <0.085 <0.086 <0.069 <0.11 <0.14 <0.15 <0.072 <0.081 <0.11 <0.053 <0.10 <0.10 <0.09 <0.031 <0.071 <0.234 <0.094 <0.14
8/18/20
6/30/21
6/1/22
7/11/23
8/18/20 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR
6/30/21 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.80 <0.40 <0.40
6/1/22 <0.09 <0.16 <0.13 <0.13 <0.11 <0.08 <0.15 <0.13 <0.11 <0.14 <0.11 <0.10 <1.00 <0.10 <0.28 <0.32 <0.10 <0.60 <0.17 <0.43
7/11/23 <0.079 <0.066 <0.085 <0.086 <0.069 <0.11 <0.14 <0.15 <0.072 <0.081 <0.11 <0.053 <0.10 <0.10 <0.09 <0.031 <0.071 <0.234 <0.094 <0.14
8/18/20
6/30/21
6/1/22
7/11/23
8/18/20
6/30/21
6/1/22
7/11/23 m&p-XyleneMW-4
MW-6
MW-5
GCL (µg/L)
Sample ID Collection Date
MW-1
MW-2
MW-3 Benzenen-Butylbenzeneo-Xylene1,2-Dibromoethane (EDB)Diisopropyl ether (IPE)Chloroform1,2-Dichloroethane1,2-DichloropropaneToluene1,2,4-Trimethylbenzene1,3,5-TrimethylbenzeneXylene (Total)n-PropylbenzeneNaphthaleneIsopropylbenzene (cumene)Methyl Tert-Butyl Ether (MTBE)sec-Butylbenzenetert-Butylbenzene2L Standard (µg/L)EthylbenzeneMW-8
MW-7
MW-9
MW-10
Well Not Sampled
Well Not Sampled - Not Located
Well Not Sampled - Not Located
Well Not Sampled - Not Located
Well Not Sampled
Well Not Sampled - Not Located
Well Not Sampled - Not Located
Well Not Sampled - Not Located
Well Not Sampled
Well Not Sampled - Not Located
Well Not Sampled - Not Located
Well Not Sampled - Obstructed
Table 3
Summary of Groundwater Analytical Results
White Rock Service Station
Prospect Hill, North Carolina
NCDEQ Incident No. 15111
(Page 2 of 2)
1 70 70 70 70 0.40 0.60 0.02 70 600 70 20 6 70 600 400 400 500 500 500
5,000 5,900 8,800 14,750 70,000 400 600 50 70,000 80,000 30,500 20,000 6,000 26,100 260,000 28,500 24,100 50,000 50,000 50,000m&p-XyleneGCL (µg/L)
Sample ID Collection Date
MW-1 Benzenen-Butylbenzeneo-Xylene1,2-Dibromoethane (EDB)Diisopropyl ether (IPE)Chloroform1,2-Dichloroethane1,2-DichloropropaneToluene1,2,4-Trimethylbenzene1,3,5-TrimethylbenzeneXylene (Total)n-PropylbenzeneNaphthaleneIsopropylbenzene (cumene)Methyl Tert-Butyl Ether (MTBE)sec-Butylbenzenetert-Butylbenzene2L Standard (µg/L)Ethylbenzene8/18/20 NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR NR
6/30/21 <0.40 1.4 0.42J <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 0.80 0.60 <0.40 0.40J 1.6 <0.40 7.3 1.7 1.5 1.5 <0.40
6/1/22 1.2 <0.16 <0.13 <0.13 <0.11 <0.08 <0.15 <0.13 0.13J <0.14 0.12J <0.10 <1.00 <0.10 0.66 1.7 0.58 1.8 1.1 0.71
7/11/23 1.0 <0.066 <0.085 <0.086 <0.069 <0.11 <0.14 <0.15 <0.072 <0.081 <0.11 <0.053 <0.10 <0.10 1.5 0.50 <0.071 0.34J <0.094 0.34J
8/18/20 523 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 106 232 28.2 <10.0 93.8 37.0 16.8 <10.0 <10.0 86.0 86.0 <10.0
6/30/21 1,400 <8.0 <8.0 <8.0 <8.0 <8.0 <8.0 <8.0 27.0 420 33.0 <8.0 170 40.0 49.0 74.0 <8.0 277 240 37.0
6/1/22 918 2.1 3.2 2.3 <0.11 <0.08 <0.15 <0.13 59.6 293 22.8 <0.10 104 38.2 31.7 16.6 <0.10 132 109 23.3
7/11/23 35.4 <0.066 0.62 0.52 <0.069 0.89 0.60 <0.15 20.1 0.33J 1.9 <0.053 0.72J <0.10 0.87 <0.031 <0.071 0.73 <0.094 0.73
8/18/20 <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 5.4 44.3 7.6 <1.0 187 9.0 1.81 95.1 48.8 57.0 52.2 4.8
6/30/21 180 0.77 0.55 0.70 <0.40 1.9 0.58 <0.40 18.0 52.0 4.1 <0.40 21.0 5.0 6.3 10.0 0.55 35.5 31.0 4.5
6/1/22 <0.09 <0.16 <0.13 <0.13 <0.11 0.35 <0.15 <0.13 2.14 0.89 0.16 <0.10 3.7 0.18 <0.28 1.5 <0.10 1.0 1.0 <0.17
7/11/23 <0.079 <0.066 <0.085 <0.086 <0.069 0.65 <0.14 <0.15 11.4 <0.081 <0.11 <0.053 0.36J <0.10 <0.09 <0.03 <0.071 <0.234 <0.094 <0.14
8/18/20 <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <3.0 <2.0 <1.0
6/30/21 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.80 <0.40 <0.40
6/1/22 <0.09 <0.16 <0.13 <0.13 <0.11 <0.08 <0.15 <0.13 <0.11 <0.14 <0.11 <0.10 <1.00 <0.10 <0.28 <0.32 <0.10 <0.60 <0.17 <0.43
7/11/23 <0.079 <0.066 <0.085 <0.086 <0.069 <0.11 <0.14 <0.15 <0.072 <0.081 <0.11 <0.053 <0.10 <0.10 <0.09 <0.03 <0.071 <0.234 <0.094 <0.14
8/18/20 <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <5.0 <1.0 <1.0 <1.0 <1.0 <3.0 <2.0 <1.0
6/30/21 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.80 <0.40 <0.40
6/1/22 <0.09 <0.16 <0.13 <0.13 <0.11 <0.08 <0.15 <0.13 <0.11 <0.14 <0.11 <0.10 <1.00 <0.10 <0.28 <0.32 <0.10 <0.60 <0.17 <0.43
7/11/23 <0.079 <0.066 <0.085 <0.086 <0.069 <0.11 <0.14 <0.15 <0.072 <0.081 <0.11 <0.053 <0.10 <0.10 <0.09 <0.03 <0.071 <0.234 <0.094 <0.14
Notes:
Bold values indicate constituent concentrations were greater than the 2L Standard.
Yellow highlighted values indicate constituent concentrations were greater than the GCL.
Samples presented prior to the May 31, 2023 event were obtained from prevous consultants reports.
<## - less than the method detection limit
µg/L - micrograms per liter
2L Standard - North Carolina 02L standard for groundwater
GCL - Gross Contaminant Level
J - Estimated concentration above the method detection limit and below the reporting limit.
NR - not reported
WSW-2
WSW-1
MW-12
MW-11
MW-13
Field Duplicate
(MW-12)7/11/23 33.7 <0.066 0.55 0.50 <0.069 0.98 0.56 <0.15 19.1 0.30J 1.8 <0.053 0.69J <0.094 0.71<0.10 0.81 <0.031 <0.071 0.71

APPENDICES

APPENDIX A

APPENDIX B

APPENDIX C

ESP Corporate Office
3475 Lakemont Boulevard
Fort Mill, SC 29708
803.802.2440

Mailing Address: P.O. Box 7030 Charlotte, NC 28241
800.960.7317 | www.espassociates.com

Concord
7144 Weddington Rd. NW
Suite 110
Concord, NC 28027
704.793.9855

Cornelius
20484 Chartwell Center Dr.
Suite D
Cornelius, NC 28031
704.649.2863

Raleigh
2200 Gateway Centre Blvd.
Suite 216
Morrisville, NC 27560
919.678.1070

Greensboro
7011 Albert Pick Rd
Suite E
Greensboro, NC 27409
336.334.7724

Wilmington
211 Racine Drive
Suite 101
Wilmington, NC 28403
910.313.6648

Charleston
2154 North Center Street
Suite E-503
North Charleston, SC 29406
843.714.2040

Nashville
500 Wilson Pike Circle
Suite 310
Brentwood, TN 37027
615.760.8300

Pittsburgh
One Williamsburg Place
Suite G-5, Box 13
Warrendale, PA 15086
724.462.6606
Bradenton
518 13th Street
West Bradenton, FL 34205
941.345.5451

Indianapolis
8673 Bash Street
Indianapolis, IN 46256
317.537.6979

Albuquerque
1203 West Ella Drive
Corrales, NM 87048
505.314.1322

Birmingham
291 Cahaba Valley Parkway North Suite A
Pelham, AL 35124
205.664.8498

Vickrey & Associates, LLC - An ESP Company

San Antonio
12970 Country Parkway
San Antonio TX 78216
210.349.3271

Austin
3600 West Parmer Lane
Suite 175
Austin, TX 78727
512.494.8014

McAllen
1216 East Jasmine Avenue
Suite C
McAllen, TX 78501
956.340.0045