HomeMy WebLinkAboutFA-3910_29832_CA_MRP_20230817SUBSEQUENT MONITORING
REPORT
CLARK BROTHERS (INCIDENT NO. 29832)
CORNER OF GREEN STREET AND COLLEGE STREET
CLARKTON, BLADEN COUNTY, NORTH CAROLINA
ESP Project No. 23-00200-020
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
August 17, 2023
ESP Associates, Inc.
P.O. Box 7030 • Charlotte, NC 28241
1.800.960.7317 • NC: 704.583.4949, fax 704.583.4950 • SC: 803.802.2440, fax 803.802.2515
www.espassociates.com
August 17, 2023
Ms. Hassan Osman
North Carolina Department of Environmental Quality
Division of Waste Management
1646 Mail Service Center
Raleigh, North Carolina 27699-1646
Email: Hassan.Osman@deq.nc.gov
Reference: SUBSEQUENT MONITORING REPORT
Clark Brothers
Corner of Green Street and College Street
Clarkton, Bladen County, North Carolina
NCDEQ Incident No: 29832
ESP Project No. 23-00200-020
Dear Mr. Osman
ESP Associates, Inc. (ESP) is pleased to present this Subsequent Monitoring Report documenting
activities performed at the subject site, Clark Brothers, in accordance with North Carolina
Department of Environmental Quality (NCDEQ), Task Authorization No. 1, approved on May 22,
2023. The subject site is located at the corner of North College Street and West Green Street in
Clarkton, 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 (704) 506-7618.
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 FREE PRODUCT EVALUATION ................................................................................ 5
3.2 WATER LEVEL GAUGING ........................................................................................ 5
3.3 GROUNDWATER SAMPLING ................................................................................... 6
3.4 FIELD QUALITY CONTROL SAMPLING AND ANALYSIS ....................................... 6
4.0 ANALYTICAL RESULTS .................................................................................................. 7
5.0 CONCLUSIONS AND RECOMMENDATIONS ................................................................. 8
6.0 REFERENCES ................................................................................................................... 9
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 Field Documentation and Photographs
Appendix C Laboratory Data Reports
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
i
SITE INFORMATION
Date of Report: August 17, 2023
NCDEQ Incident No: 29832
NCDEQ UST No.: FA-3910
Site Name: Clark Brothers
Site Location: Corner of Green Street and College Street
Clarkton, Bladen County, North Carolina 28433
Latitude: N 34.487809
Longitude: W 78.656136
UST Owner/ Operator: Brisson Oil Company (Dissolved)
Current Property
Owner: Gary Michael Melvin
P.O. Box 814
Clarkton, North Carolina 28433
Current Property
Occupant: N/A- property is not currently occupied. Currently used for parking
for adjacent business.
Consultant: ESP Associates, Inc.
P.O. Box 7030
Charlotte, North Carolina 28241
(704) 583-4949
Laboratory: Pace Analytical Services, LLC
NCDEQ No. 5342
9800 Kincey Avenue
Huntersville, North Carolina 28028
(704) 875-9092
Release Information: Release Discovery Date: unknown, discovered in 2003
Estimate Quantity: Unknown
Cause of Release: Leaking UST system
Source of Release: Possibly two 6,000-gallon USTs and an
additional two to four USTs of unknown size
Active Tanks: None
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
ii
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
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
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 Clark Brothers site (Incident No. 29832). The site is an
approximately 0.21-acre developed site (Tax Parcel No. 0007734) located at the corner of North
College Street and West Green Street in Clarkton, Bladen County, North Carolina. This report was
completed to summarize the findings of assessment activities performed on June 14, 2023, in
accordance with North Carolina Department of Environmental Quality (NCDEQ), Task
Authorization No. 1, approved on May 22, 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).
Field activities performed by ESP on June 14, 2023, included:
• Gauging static water levels in monitoring wells MW-18, MW-19, MW-20, and MW-21;
• Gauging the level of free product in MW-21; and
• Collecting groundwater samples from MW-18, MW-19, and MW-20, along with a field
duplicate. Although planned, ESP was unable to obtain a groundwater sample from MW-
21 as free product was present.
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).
Based on results of the above field activities and previous reporting, ESP concludes the following:
• Static water level depths beneath the site ranged from 11.10 ft to 12.60 ft bTOC;
• The general direction of shallow groundwater flow beneath the site is toward the south-
southwest;
• The site and surrounding areas are connected to municipal water which obtains its water from
a water supply well (TOC WSW-1) located approximately 1,000 feet northwest of the site.
No other water supply wells have been identified within 1,000 feet of the site;
• Free product was measured at a thickness of 0.05 ft in MW-21 and thus a groundwater
sample was not collected for laboratory analysis;
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
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• The AFVR event conducted on June 29, 2022, appears to have reduced the thickness of
free product in MW-21 but did not eliminate its presence;
• No VOCs were detected above their GCLs in any of the sampled monitoring wells;
• Several VOCs were detected above their respective 2L standards in MW-18, MW-19, and
MW-20;
• A comparison of groundwater analytical results from the June 14, 2023, sampling event to
sampling events conducted since April 2019, reveals that constituent concentrations in
MW-18 have generally remained relatively stable; while concentrations in MW-19 and
MW-20 have generally decreased.; and
• The June 29, 2022, AFVR event using MW-21 appears to have reduced free product thickness
in MW-21 while dissolved concentrations in site monitoring wells decreased.
Based on the above results, ESP offers the following recommendations:
• Continue to sample site monitoring wells on a semi-annual basis to further understand
concentration trends and plume stability;
• Continue to gauge free product thickness in MW-21. Purge and obtain groundwater sample
if no product is present;
• Consider an additional AFVR event on MW-21 to extract free product and reduce dissolved
contaminant concentrations; and
• Consider installing ORC sleeves in MW-18, MW-20, and MW-21 to further aid in
contaminant degradation and plume stability.
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
1
1.0 INTRODUCTION
1.1 Site Setting
The Clark Brothers site is an approximate 0.21-acre site (Tax Parcel No. 0007734) located at the
northwest corner of the intersection of North College Street and West Green Street in Clarkton,
Bladen County, North Carolina (see Figures 1 and 2). The site was originally the location of Clark
Brothers convenience store. No physical structures are presently on the site which currently serves
as a paved parking lot for the adjacent Melvin Automotive and includes various parked automobiles
in disrepair. The site is bounded to the north by a garage for Melvin Automotive; to the west by an
undeveloped lot; to the south by West Green Street and beyond by a Family Dollar; and to the east
by North College Street and beyond by a vacant bank.
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 in the Coastal Plain Region, or Inner Coastal Plains. This region is a higher, denser area
of sandy soil. The Coastal Plain Region was developed on loose, unconsolidated, and flat layers
of sediment, caused by sea level changes and erosion of the mountains. Most parts of the Coastal
Plain Region consist of well to moderately well-drained loamy soils.
The site is underlain by a sequence of marine sediments of the Cretaceous age known as the Black
Creek Formation (Kb). The Black Creek Formation consists of thin beds of fine grained,
micaceous sand and thick beds of coarse sand with fossiliferous clay in the upper layers. The soil
on the site was found to consist of Dragston fine sandy loan, 0 to 2 percent slopes (Da). Da soil
types are found in the uplands. They are developed from beds of sand that grade into and are
interbedded with light sandy clays. Da soil types are somewhat poorly drained, with slow runoff,
and depth to the water table is at or near the surface in lower areas.
Groundwater at the site is supplied by the Black Creek Aquifer. The aquifer’s characteristics are
lagoonal to marine consisting of thinly laminated clay interlayered with sand. Sediments in the
subsurface are highly organic and are from the Black Creek and Middendorf Formations. On
average, the Black Creek Aquifer consists of “nearly 60 percent sand”, and the hydraulic
conductivity ranges from 15 to 50 feet/day, averaging 28 feet/day. Recharge of the groundwater is
the result of downward percolation from the overlying aquifers. Discharge is typically into streams
where there are channels cut into it or its overlying confining unit.
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, and the influences of groundwater pumping. Based
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
2
on depth-to-water level measurements, the general groundwater flow direction beneath the site is
estimated to be toward the south and southwest.
1.3 Surface Water
An unnamed intermittent stream is located approximately 890 feet north-northeast of the source area
(see Figure 1). The stream does not serve as a runoff or tributary to a larger body of water. There
are no other notable surface water features within 1,000 feet of the site.
1.4 Water Supply Wells
Based on previous receptor surveys conducted by others, a water supply well (TOC WSW-1) was
identified on an upgradient property located at 81 Elm Street approximately 1,000 feet northwest
of the site (see Figure 6). This water supply well reportedly serves as the municipal water supply
for the city of Clarkton. No other water supply wells have been identified within 1,000 feet of the
site.
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
3
2.0 SITE HISTORY
The following description of historical site activities was obtained from a report titled “Subsequent
Monitoring Report, Clark Brothers (Incident #29832)” dated November 2, 2021, by Terracon
Consultants Inc. (Terracon) and a report titled “Aggressive Fluid Vapor Recovery Event Letter
Report, Clark Brothers” dated August 4, 2022, by Terracon.
• The site and surrounding areas are connected to municipal water which obtains its water
from a water supply well (TOC WSW-1) located approximately 1,000 feet northwest
of the site.
• The site’s former UST system comprised of two 6,000-gallon gasoline USTs and an
additional two to four USTs of unknown capacity. The entire UST network was removed
in 1998.
• Monitoring wells MW-18, MW-19, MW-10, and MW-21 were installed in association
with the groundwater assessment for the Butler’s BP (Incident #21816), which is directly
adjacent to the Clark Brothers site.
• A release was identified when free product was observed in MW-20 and MW-21 during
a 2003 sampling event for the Butler’s BP site. Free product has been consistently
observed in MW-21 since 2012.
• There were also several adjacent and off-site petroleum release incidents and/or former
gasoline stations that may have contributed to the contamination in the on-site and off-
site monitoring wells. These incidents/properties included Butler’s BP (Incident
#21816) at 10519 South College Street, a former gasoline station at 7 East Green Street,
and the former Green Residence (Incident #29902) at 10528 South College Street.
• In 2016, S&ME performed a site reconnaissance and receptor survey on the site. They
confirmed the presence of the town’s municipal water supply well within 1,000 feet of
the site and confirmed the presence of free product in MW-21. It was also confirmed that
the site is situated within a Well Head Protection Area.
• In 2016, NCDEQ closed out the Butler’s BP incident and transferred ownership of MW-
18 through MW-21 to the State-Lead Program to continue monitoring and remedial
efforts on the Clark Brothers site.
• In 2019, S&ME mobilized to conduct a groundwater sampling event, and to gauge the
free product present in MW-21. S&ME measured 0.88 feet of free product present in
MW-21. Several constituents were present above their 2L standards in MW-18 through
MW-20, but none exceeded their GCL.
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
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• In 2019 and 2020, S&ME would re-mobilize each year to continue to monitor
development of the plume and gauge for free product. Both sampling events yielded the
same results, with free product present in MW-21 and several constituents above 2L
standard but below GCL in MW-18 through MW-20.
• On September 16, 2021, Terracon mobilized to conduct a sampling event for monitoring
wells MW-18 through MW-20. MW-21 was to be hand bailed of free product and
sorbent socks were to be installed to reduce free product in the well. Approximately 7
gallons of free product were removed from MW-21 and disposed of offsite. After
sampling, an Oxygen Release Compound (ORC) sock was installed in MW-20 to reduce
the concentration of petroleum constituents.
• On June 29, 2022, Terracon, along with subcontractor Hazmat Emergency Response and
Remediation (HERR), mobilized to perform an Aggressive Fluid Vapor Recovery event
(AFVR). HERR proceeded to perform the recovery for 8 hours, extracting the vapors via
MW-21. Approximately 0.02 gallons of gasoline were recovered from MW-21, with a
total liquid recovery volume of 1,375 gallons of fluid.
Historical groundwater elevations and analytical results are provided in Appendix A.
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
5
3.0 FIELD ACTIVITIES
Field activities performed by ESP on June 14, 2023, included:
• Gauging static water levels in monitoring wells MW-18, MW-19, MW-20, and MW-21;
• Gauging the level of free product in MW-21; and
• Collecting groundwater samples from MW-18, MW-19, and MW-20, along with a field
duplicate. Although planned, ESP was unable to obtain a groundwater sample from MW-
21 as free product was present.
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 Free Product Evaluation
On June 14, 2023, free product was measured using an oil/water interface probe in monitoring well
MW-21 at a thickness of 0.05 feet. Free product has been observed in MW-21 consistently since
2012 and was previously reported at a thickness of 1.04 feet on September 21, 2021. The AFVR
event conducted on June 29, 2022, appears to have reduced the thickness of free product in MW-
21 but did not eliminate its presence.
3.2 Water Level Gauging
On June 14, 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 1, static water level depths ranged from 11.10 ft to 12.60 ft below top of casing
(ft bTOC). Figure 3 depicts the groundwater elevations based off a benchmark of 100.00 ft given
to an arbitrary point on site as noted in previous reporting. As depicted in Figure 3, shallow
groundwater flow beneath the site is toward the south and southwest.
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
6
3.3 Groundwater Sampling
On June 14, 2023, groundwater samples were collected from monitoring wells MW-18, MW-19,
and MW-20. Due to the presence of free product in MW-21, a groundwater sample was not
collected for analysis from this monitoring well.
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 and 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).
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).
3.4 Field Quality Control Sampling and Analysis
A field duplicate groundwater sample, designated Field Duplicate, was collected on June 14, 2023,
from MW-19 and analyzed for VOCs by EPA Method 6200B including MTBE, EDB, and IPE to
assess variance between collected samples.
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
7
4.0 ANALYTICAL RESULTS
Results of the laboratory analysis of groundwater samples MW-18, MW-19, and MW-20 are
tabulated in Table 3. As noted 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 each of the
three sampled monitoring wells (see Table 3). A summary of the analytical results is as follows:
• In MW-18, benzene (21.6 µg/L), cumene (83.3 µg/L), naphthalene (45.0 µg/L), n-
propylbenzene (176 µg/L), and total xylenes (574 µg/L) were all detected above their
respective 2L standards;
• In MW-19, naphthalene (44.9 µg/L) was detected above its 2L standard; and
• In MW-20, benzene (726 µg/L), naphthalene (277 µg/L), and total xylenes (1,471 µg/L)
were all detected above their respective 2L standards.
Groundwater sampling results relative to each well location depicting VOCs exceeding their 2L
standard or GCL are provided on Figure 4 while Figure 5 depicts the approximate lateral extent
of the dissolved benzene groundwater plume.
A comparison of groundwater laboratory analytical results from the June 14, 2023, sampling event
to sampling events conducted since April 2019, reveals the following:
• In MW-18, constituent concentrations have generally remained relatively stable;
• In MW-19, constituent concentrations have generally decreased somewhat; and
• In MW-20, constituent concentrations have decreased.
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
8
5.0 CONCLUSIONS AND RECOMMENDATIONS
Based on results of the above field activities and previous reporting, ESP concludes the following:
• Static water level depths beneath the site ranged from 11.10 ft to 12.60 ft bTOC;
• The general direction of shallow groundwater flow beneath the site is toward the south-
southwest;
• The site and surrounding areas are connected to municipal water which obtains its water from
a water supply well (TOC WSW-1) located approximately 1,000 feet northwest of the site.
No other water supply wells have been identified within 1,000 feet of the site;
• Free product was measured at a thickness of 0.05 ft in MW-21 and thus a groundwater
sample was not collected for laboratory analysis;
• The AFVR event conducted on June 29, 2022, appears to have reduced the thickness of
free product in MW-21 but did not eliminate its presence;
• No VOCs were detected above their GCLs in any of the sampled monitoring wells;
• Several VOCs were detected above their respective 2L standards in MW-18, MW-19, and
MW-20;
• A comparison of groundwater analytical results from the June 14, 2023, sampling event to
sampling events conducted since April 2019, reveals that constituent concentrations in
MW-18 have generally remained relatively stable; while concentrations in MW-19 and
MW-20 have generally decreased.; and
• The June 29, 2022, AFVR event using MW-21 appears to have reduced free product thickness
in MW-21 while dissolved concentrations in site monitoring wells decreased.
Based on the above results, ESP offers the following recommendations:
• Continue to sample site monitoring wells on a semi-annual basis to further understand
concentration trends and plume stability;
• Continue to gauge free product thickness in MW-21. Purge and obtain groundwater sample
if no product is present;
• Consider an additional AFVR event on MW-21 to extract free product and reduce dissolved
contaminant concentrations; and
• Consider installing ORC sleeves in MW-18, MW-20, and MW-21 to further aid in
contaminant degradation and plume stability.
Subsequent Monitoring Report ESP Project No. 23-00200-020
Clark Brothers (Incident #29832) August 17, 2023
9
6.0 REFERENCES
Bladen County, North Carolina GIS website, https://gis.bladenco.org/.
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, November 2, 2021, Subsequent Monitoring Report: Clark Brothers, Clarkton, Bladen
County, North Carolina.
Terracon, August 4, 2022, Letter Report: Aggressive Fluid Vapor Recovery Event Letter Report,
Clark Brothers, Clarkton, Bladen County, North Carolina.
FIGURES
0 350 700Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone 704.583.4949
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-020
ET
CWDATE08/01/2023
FIGURE 1USGS TOPOGRAPHIC SITE LOCATION MAPµAs Shown
CHARLOTTE, NORTH CAROLINA
SITE BOUNDARY
All locations are approximate.
CLARK BROTHERS SITE
LEGEND:
<
<
<
<
MW-21
MW-20
MW-19
MW-18
MELVIN AUTOMOTIVE
NORTH COLLEGE STREETCOX STREETWEST GREEN STREET
0 20 40Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone 704.583.4949
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-020
ET
CWDATE08/01/2023
FIGURE 2SITE MAPµAs Shown
CHARLOTTE, NORTH CAROLINA
SITE BOUNDARY
MONITORING WELL
All locations are approximate.
CLARK BROTHERS SITE
LEGEND:
<
<
<
<
<
MW-21
MW-20
MW-19
MW-18NORTH COLLEGE STREETCOX STREETWEST GREEN STREET
0 10 20Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone 704.583.4949
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-020
ET
CWDATE08/01/2023
FIGURE 3GROUNDWATER ELEVATION MAPJUNE 14, 2023µAs Shown
CLARKTON, NORTH CAROLINA
SITE BOUNDARYMONITORING WELLESTIMATED GROUNDWATER ELEVATION CONTOURESTIMATED GROUNDWATER FLOW DIRECTION
All locations are approximate.
CLARK BROTHERS SITE
LEGEND:
<
<
<
<
<
MW-21
MW-20
MW-19
MW-18NORTH COLLEGE STREETCOX STREETWEST GREEN STREET
0 10 20Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone 704.583.4949
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-020
ET
CWDATE08/01/2023
FIGURE 4GROUNDWATER RESULTS MAPJUNE 14, 2023µAs Shown
CLARKTON, NORTH CAROLINA
SITE BOUNDARY
MONITORING WELL
All locations are approximate.
CLARK BROTHERS SITE
LEGEND:
<
<
<
<
<
MW-21
MW-20
MW-19
MW-18NORTH COLLEGE STREETCOX STREETWEST GREEN STREET
0 10 20Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone 704.583.4949
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-00200-020
ET
CWDATE08/01/2023
FIGURE 5BENZENE ISOCONCENTRATION MAPJUNE 14, 2023µAs Shown
CLARKTON, NORTH CAROLINA
SITE BOUNDARY
MONITORING WELL
ISOCONCENTRATION CONTOUR
All locations are approximate.
CLARK BROTHERS SITE
LEGEND:
<
PLANK ROAD
GADDY'S FERRY ROADED
WSW-6 WSW-3
ED
WSW-8
ED
WSW-9
ED
ED
WSW-2
WSW-11
WSW-5
ED
ED
WSW-4
WSW-1A&B
ED
ED
WSW-12
WSW-14
ED
ED
500-ft
1,000-ft
0 110 220Feet
ESP Associates, Inc.
P.O. Box 7030Charlotte, NC 28241
Phone 704.583.4949
www.espassociates.com
SHEET TITLE
PROJECT
PROJECT NO.
SCALE
DRAWN BY
CHECKED BY
23-0200-020
ET
CWDATE08/07/2023
FIGURE 6WATER SUPPLY WELL RADIUS MAPµAs Shown
CLARKTON, NORTH CAROLINA
SITE BOUNDARYWATER SUPPLY WELLWATER SUPPLY WELL (ABANDONED)RIVERINE WETLANDFRESHWATER POND
All locations are approximate.
CLARK BROTHERS SITE
LEGEND:
ED
ED
TABLES
Table 1
Water Supply Well Information
Clark Brothers
Clarkton, North Carolina
NCDEQ Incident No. 29832
Well No.Property Owner Mailing
Address
Property
Address
Distance from
Source Area
(feet)
Hydraulic
Relationship to
Source Area
Well
Status/Use
Municpal
Water Parcel ID No.
TOC WSW-1 Town of Clarkton
P.O. Box 307
Clarkton, NC
28433
81 Elm Street
Clarkton, NC
28433
~1,000 feet
northwest Upgradient Active -
Potable
Yes
(Municipal
Well)
120606299472
Notes:
Information obtained from previous monitoring report.
Table 2
Monitoring Well Construction and Groundwater Elevation Data
Clark Brothers
Clarkton, North Carolina
NCDEQ Incident No. 29832
Well ID Date
Intalled
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)
4/17/19 8.90 88.69 .---
8/11/20 10.20 87.39 .---
2/8/21 8.87 88.72 .---
9/16/21 11.78 85.81 .---
6/14/23 12.60 84.99 .---
4/17/19 9.09 88.57 .---
8/11/20 10.09 87.57 .---
2/8/21 8.00 89.66 .---
9/15/21 10.67 86.99 .---
6/29/22 12.67 84.99 .---
6/14/23 12.46 85.20 .---
4/17/19 8.78 88.16 .---
8/11/20 10.28 86.66 .---
2/8/21 8.43 88.51 .---
9/15/21 10.07 86.87 .---
6/29/22 12.65 84.29 .---
6/14/23 11.97 84.97 .---
4/17/19 8.93 88.35 0.88
8/11/20 9.93 87.20 0.67
2/8/21 8.36 88.72 0.60
9/15/21 11.27 86.13 1.04
6/29/22 11.86 84.98 0.27
6/14/23 11.10 85.58 0.05
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 obtained from a prior report prepared by Terracon.
-- - no measureable free product
BGS - below ground surface
ft - feet
ft bTOC - feet below TOC
FP - free product
TOC - top of casing
17.0
17.0
MW-21 10/17/2003 2.0-17.0 96.6417.0
c Groundwater elevation adjusted for measurable 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-18
MW-19
MW-20
10/17/2003
10/17/2003
10/17/2003
2.0-17.0
2.0-17.0
2.0-17.0 96.94
97.66
17.0
97.59
Table 3
Summary of Groundwater Analytical Results
Clark Brothers
Clarkton, North Carolina
NCDEQ Incident No. 29832
(Page 1 of 1)
1 70 70 70 70 0.02 70 600 70 20 6 70 70 600 400 400 500 500 500
5,000 5,900 8,800 14,750 70,000 50 70,000 80,000 30,500 20,000 6,000 26,100 70,000 260,000 28,500 24,100 50,000 50,000 50,000
4/17/19 17.0 33.0 29.0 3.6 <1.7 <1.9 <1.7 420 18.0 <2.5 180 270 <1.1 44.0 200 130 254 210 44.0
8/11/20 28.0 44.0 27.0 3.5 <0.85 <0.95 <0.85 400 79.0 <1.2 41.0 200 <0.55 23.0 200 110 472 430 42.0
9/16/21 66.0 <8.0 13.0 <8.0 <8.0 <8.0 <8.0 760 68.0 <8.0 33.0 150 <8.0 87.0 220 130 1,740 1,500 240
6/14/23 21.6 <1.2 <1.0 <0.81 <1.1 <0.68 <0.77 397 83.3 <1.1 45.0 176 <0.73 17.4 228 126 574 498 75.9
4/17/19 8.7 4.3 3.9 <1.7 <1.7 <1.9 <1.7 360 27.0 <2.5 100 53.0 1.7 340 200 35.0 1,100 680 330
8/11/20 8.5 11.0 4.6 <1.7 <1.7 <1.9 <1.7 650 50.0 <2.5 96.0 80.0 <1.1 270 430 100 1,900 1,600 300
9/16/21 <20.0 <20.0 <20.0 <20.0 <20.0 <20.0 <20.0 970 64.0 <20.0 110 130 <20.0 620 480 160 3,410 2,700 710
6/14/23 0.61 <0.49 <0.40 <0.32 <0.43 <0.27 <0.31 57.5 22.5 <0.42 44.9 39.6 <0.29 1.5 36.8 3.8 45.5 43.0 2.5
4/17/19 3,100 16.0 <6.4 <6.8 <6.8 12.0 <6.8 1,700 100 <10.0 530 130 27.0 450 1,100 380 4,900 3,900 1,000
8/11/20 1,900 29.0 9.2 <3.4 <3.4 6.8 <3.4 1,500 33.0 <5.0 410 110 <2.2 200 970 300 3,570 3,200 370
9/16/21 2,800 <20.0 <20.0 <20.0 <20.0 <20.0 <20.0 1,100 48.0 <20.0 260 67.0 <20.0 98.0 570 250 2,150 1,900 250
6/14/23 726 <2.4 <2.0 <1.6 <2.2 <1.4 <1.5 475 28.4 <2.1 277 29.0 10.1 598 278 92.2 1,471 1,110 361
4/17/19
8/11/20
9/16/21
6/14/23
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 June 14, 2023 event were obtained from previous consultants reports.
<## - less than the Method Detection Limit (MDL)
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
1.5 <0.49 <0.40 <0.32 56.7Field Duplicate
(MW-19)
GCL (µg/L)
Sample ID Collection Date
MW-18
MW-19
6/14/23
2L Standard (µg/L)n-PropylbenzeneBenzenen-Butylbenzenesec-Butylbenzenetert-Butylbenzene1,2-Dibromethane (EDB)Diisopropyl ether (IPE)ChloroformEthylbenzeneIsopropylbenzene (cumene)Methyl Tert-Butyl Ethyl (MTBE)Naphthalene<0.42<0.43 <0.27 <0.31 43.321.0 36.8 2.1 36.9 4.0 49.5 46.8 2.7Styrene<0.29 o-XyleneToluene1,2,4-Trimethylbenzene1,3,5-TrimethylbenzeneXylene (Total)m&p-XyleneMW-20
Not Sampled - Free Product Detected
Not Sampled - Free Product Detected
Not Sampled - Free Product Detected
Not Sampled - Free Product Detected
MW-21
APPENDICES
APPENDIX A
APPENDIX B
APPENDIX C
ESP Corporate Office
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205.664.8498
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210.349.3271
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512.494.8014
McAllen
1216 East Jasmine Avenue
Suite C
McAllen, TX 78501
956.340.0045