AS-243_3701_CA_RPTS_20210921_Treatability and Modelling

CONTAMINANT FATE AND TRANSPORT
MODELING REPORT
Lewis Service Station (Incident # 3701)
4733 Fallston Road
Fallston, Cleveland County, North Carolina
September 21, 2021
Terracon Project No. 71179012A

Prepared for:
North Carolina Department of Environmental Quality
Division of Waste Management
Raleigh, North Carolina

Prepared by:
Terracon Consultants, Inc.
Charlotte, North Carolina

Table of Contents
A. SITE INFORMATION................................................................................................ 1
B. EXECUTIVE SUMMARY .......................................................................................... 2
C. SITE HISTORY AND CHARACTERIZATION ........................................................... 4
C.1 Site Setting ....................................................................................................................................... 4
C.2 Release Summary ........................................................................................................................... 4
C.3 Previous Investigations .................................................................................................................. 5
C.4 Water Supply Wells ......................................................................................................................... 6
C.5 Surface Water .................................................................................................................................. 6
C.6 Land Use Information ..................................................................................................................... 6
D. ASSESSMENT INFORMATION ............................................................................ 7
D.1 Site Geology and Hydrogeology .................................................................................................... 7
D.2 Treatability Study ............................................................................................................................ 8
E. AQUIFER TESTING ................................................................................................. 8
F. GROUNDWATER MODELING ................................................................................ 9
G. CONCLUSIONS AND RECOMMENDATIONS ................................................... 11

FIGURES
Figure 1: Site Location Map
Figure 2: Site Plan
Figure 3: Water Supply Well Location Map
Figure 4: Groundwater Elevation Map (March 2021)
Figure 5: Groundwater Analytical Results (March 2021)
Figure 6: Mann Kendall Analysis – Benzene
Figure 7: Mann Kendall Analysis – EDB
Figure 8: Mann Kendall Analysis – MTBE

TABLES
Table 1: Historical UST Information
Table 2: Water Supply Well Information
Table 3: Summary of Groundwater Analytical Results
Table 4: Monitoring Well Construction Information and Historical Groundwater Elevations

APPENDIX
Appendix A: RemRx Remediation Treatability Study
Appendix B: Field Notes
Appendix C: AQTESOLV Results
Appendix D: RBCA Toolkit Model Results
Lewis Service Station
Fallston, North Carolina
Project Number 71179012A
Incident No. 3701
September 21, 2021

Responsive ■ Resourceful ■ Reliable 1
CONTAMINANT FATE AND TRANSPORT MODELING REPORT
A. SITE INFORMATION
Date of Report: September 24, 2021
NCDEQ Incident No: 3701
Facility ID: Unknown
Site Name: Lewis Service Station
Site Location: 4733 Fallston Road
Fallston, Cleveland County, North Carolina

Latitude / Longitude: N 35.428201” W -81.501616

UST Owner/Operator: Petroleum World, Inc.
681 NC 120 Highway
Mooresboro, North Carolina 28114

Current Property Owner: Cool Cycle, Inc.
PO Box 766
Fallston, North Carolina 28042

Current Property
Occupant: Cool Cycle, Inc.

Consultant: Terracon Consultants, Inc. (Contact: Will Frazier)
2701 Westport Road
Charlotte, North Carolina 28208
[phone]

Laboratory: Pace Analytical (NCDEQ No. 5342)
9800 Kincey Street, Suite 100
Huntersville, North Carolina 28078
704-875-9092

Release Information: Release Discovery Date: December 27 and 28, 1994
Estimated Quantity: Unknown
Cause of Release: Unknown
Source of Release: Former gasoline UST system
Currently Active Tanks: None – (2) 1,000-gallon gasoline USTs
abandoned in place and (1) 1,000-gallon kerosene UST removed from
the site.

Lewis Service Station
Fallston, North Carolina
Project Number 71179012A
Incident No. 3701
September 21, 2021

Responsive ■ Resourceful ■ Reliable 3
soil lithologies reported in the Comprehensive Site Assessment Report completed by Shield in
December 1995, which described the site lithologies as “stiff silty clay grading into heterogenous
inorganic micaceous silts.” In addition, the values are generally consistent with the hydraulic
conductivity reported in Shield’s May 1996 Corrective Action Plan (0.197 ft/day [or 72 ft/yr] based on
slug tests of MW-2, MW-3, and MW-6).

Terracon utilized available site-specific data (contaminant concentrations, hydraulic gradient, and
hydraulic conductivity) to simulate natural attenuation and transport of the contaminant plume. The
model simulations to evaluate solute transport was completed using the RBCA Tool Kit for Chemical
Releases® Version 2.6. Two different models were utilized: 1) a model simulating biodegradation
through the use of 1st order decay constants for contaminants of concern (i.e. decay half-lives); and
2) a dispersion only model. The biodegradation model indicates that concentrations of the
contaminants of concern in excess of the calculated concentrations limits never reach the point of
exposure (e.g. WSW-Cotton Gin). The steady-state concentrations calculated to exist at the point of
exposure range from 1.9 x 10-9 µg/L (benzene) to 1.2 x10-66 µg/L (toluene). The calculated total
carcinogenic risk (4.1 x 10-16) and hazard index (3.0 x 10-11) for the point of exposure are many
orders of magnitude lower than NCDEQ’s acceptable risk tolerances of 1.0 x 10-4 and 1,
respectively.

The dispersion only model results indicate that WSW-Cotton Gin is highly unlikely to become
impacted by the petroleum concentrations currently detected at the site. The model calculates that
benzene, toluene, ethylbenzene, total xylene, and MTBE will never reach the calculated
concentration limit at the point of exposure. While the model indicates that EDB would reach its
concentration limit at the point of exposure (calculated as 0.34 µg/L; the RBCA Toolkit® does not
allow for manually entering the 2L standard of 0.02 µg/L for the point of exposure concentration limit)
after 123.1 years, it must be noted that the calculated total carcinogenic risk (7.2 x 10-5) and hazard
index (0.31) for the point of exposure are lower than NCDEQ’s acceptable risk tolerances of 1.0 x
10-4 and 1, respectively.

As the more conservative, dispersion only, model indicates minimal risk to WSW-Cotton Gin, and
the more realistic model that includes biodegradation indicates virtually zero risk to WSW -Cotton
Gin, it does not appear likely that the on-site contaminant concentrations will impact the water supply
well in the future. As such, the site’s remediation targets can be set as the GCLs rather than the 2L
standards.

The treatability study performed by RemRx Remediation indicated that iron-activated hydrogen
peroxide effectively degrades EDB as well as other contaminants found at the site (e.g. benzene,
naphthalene, etc.) at relatively modest to higher doses. A solid form of hydrogen peroxide, sodium
percarbonate, was also evaluated and found to be effective in degrading contaminant
concentrations. The reaction kinetics of sodium percarbonate are more efficient at lower pH; as
such, an acid buffer may be necessary to adjust groundwater pH if sodium percarbonate is chosen
as a treatment for the site.
Lewis Service Station
Fallston, North Carolina
Project Number 71179012A
Incident No. 3701
September 21, 2021

Responsive ■ Resourceful ■ Reliable 4
Based on the findings of our assessment activities, the following comments and recommendations are
provided for the site.
Terracon recommends coordinating with RemRx Remediation to determine the proper dosing of
hydrogen peroxide or sodium percarbonate necessary to reduce site contaminants to below their
GCLs. The remediation compounds would be emplaced within augered boreholes located within
the source zone.
Following the installation of the remediation compound(s), semi-annual monitoring at the site
should be completed to demonstrate that concentrations have been reduced to and remain below
their GCLs. Once this can be demonstrated, the site would then be eligible for closure with
issuance of a Notice of Residual Petroleum (NORP).
C. SITE HISTORY AND CHARACTERIZATION
This Contaminant Fate and Transport Modeling Report was prepared for the site in response to a
request by Mr. Mark Petermann, NCDEQ Incident Manager with the Division of Waste Management,
State Lead Program. The purpose of this report is to determine the appropriate remediation goals at
the former Lewis Service Station site located at 4733 Fallston Road in Fallston, Cleveland County,
North Carolina (Figures 1 and 2) as well as evaluate whether hydrogen peroxide and/or sodium
percarbonate can effectively degrade the contaminants located at the site.

The Contaminant Fate and Transport Modeling 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, dated July 15, 2008, revised
May 2021, under the supervision of Mr. William O. Frazier, a North Carolina registered professional
geologist (North Carolina License No. 2576).

C.1 Site Setting
The site is located within an area primarily developed as commercial. A park is located on the
adjacent property to the north and Tropical Creations is located on the adjacent property to the
south. The site is bound to the east by Fallston Road and a residence is located on the adjacent
property to the west. Specific land uses are further described in Section C.6 below.

C.2 Release Summary
Based on regulatory file review information, the site formerly operated two 1,000-gallon gasoline
USTs, one 1,000-gallon kerosene UST, and two ASTs related to on-site fueling operations. A
potential release was discovered on December 27 and 28, 1994. The suspected release was from
the 1,000-gallon gasoline UST located near the southeastern corner of the on-site building.
Historical UST information is provided in Table 1.

Lewis Service Station
Fallston, North Carolina
Project Number 71179012A
Incident No. 3701
September 21, 2021

Responsive ■ Resourceful ■ Reliable 5
C.3 Previous Investigations
Based on regulatory file review information, the site formerly operated two 1,000-gallon gasoline
USTs, one 1,000-gallon kerosene UST, and two ASTs related to on-site fueling operations. A
potential release was discovered on December 27 and 28, 1994. The suspected release was from
the 1,000-gallon gasoline UST located near the southeastern corner of the on-site building.
Reportedly, the two 1,000-gallon gasoline USTs were abandoned in place and the 1,000-gallon
kerosene UST was removed from the site.

Most of the monitoring well network was installed during Comprehensive Site Assessment (CSA)
activities in 1995. Between 1999 and 2003, numerous monitoring events were completed at the site.
In addition, three Aggressive Fluid and Vapor Recovery events were completed during that time.
The monitoring well network has been sampled on an approximate annual basis since 2012. The
results of the monitoring events are summarized in Table 3.

In May 2016, Shield Engineering Inc. (Shield) conducted a 96-hour Mobile Multiphase Extraction
Event (MMPE) at on-site wells MW-1, VMW-1 and RW-1. Approximately 3,600 gallons of dissolved
phase impacted groundwater were recovered during the MMPE event. An estimated 32 gallons of
free product (gasoline) were removed from the site as vapor. A subsequent well sampling event on
June 14, 2016 indicated contaminant concentrations had generally decreased as a result of the
MMPE event. Constituent concentrations were below their respective GCLs but remained above
their respective 2L standards.

In August 2017, Terracon conducted a groundwater sampling event on wells MW-1, RW-1, and
VMW-1. Groundwater depths ranged from 26.60 feet (well RW-1) to 26.97 feet (well VMW-1) bgs.
Benzene was detected in well RW-1 above its GCL and various constituents were detected above
their respective 2L standards in wells VWM-1 and MW-1.

In June 2019, Terracon sampled monitoring wells MW-1 through MW-6, MW-8, RW-1, VMW-1 and
SSMW-2 (from adjoining Stamey Store property to east). VOC concentrations had decreased
dramatically (e.g. benzene decreased by an order of magnitude and no longer exceeded its GCL in
well RW-1, and a maximum concentration of 509 µg/L in well MW-1) except for EDB, which was
identified above its GCL in well MW-1. Terracon also collected additional samples from wells MW-
2, VMW-1, and RW-1 for analysis of natural attenuation parameters including dissolved gases
(ethane, ethene and methane), dissolved oxygen, ferrous iron, nitrate, nitrite, sulfate and alkalinity.
The three wells were also evaluated for biodegradation potential using QuantArray-Petro to identify
aerobic and anaerobic biodegradation organisms.

These results indicate wells VMW-1 and RW-1 contain microorganisms responsible for aerobic
biodegradation of BTEX and MTBE, specifically Methylibium petroleiphilum (PM1), Phenol
Hydroxylase (PHE), Toluene 2 Monooxygenase (RDEG), Toluene Ring Hydroxylating
Monooxygenases (RMO), and Ethylbenzene/Isopropylbenzene Dioxygenase (EDO). Well RW-1
Lewis Service Station
Fallston, North Carolina
Project Number 71179012A
Incident No. 3701
September 21, 2021

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contains the highest volume of microorganisms. Well RW-1 also contains Naphthalene
Dioxygenase (NAH), which is a microorganism responsible for aerobic biodegradation of PAHs and
alkanes; however, the population is small. Benzoyl Coenzyme A Reductase (BCR) and
Benzylsuccinate Synthase (BSS) are microorganisms responsible for anaerobic biodegradation of
BTEX, while Naphthylmethylsuccinate Synthase (MNSSA), Naphthalene Carboxylase (ANC) and
Alkylsuccinate Synthase (ASSA), microorganisms responsible for anaerobic biodegradation of PAHs
and alkanes were also found in wells VMW-1 and RW-1. Other bacteria detected in the wells
included Total Eubacteria (EBAC) and Sulfate Reducing Bacteria (APS).

In March 2021, Terracon conducted a sampling event of the on- and off-site monitoring well
network. The analytical results indicated broadly similar concentrations trends at the site, with most
constituent concentrations decreasing but EDB increasing within MW-1 and remaining above its
GCL. Groundwater analytical result and a groundwater flow map for the surficial aquifer at the site,
prepared from depth to water measurements collected during the most recent sampling event in
March 2021, are provided as Figures 4 and 5, respectively.

C.4 Water Supply Wells
Two water supply wells were identified within 1,500 feet of the source area as reported by Shield in
2016. Well WSW-4, located on the adjacent property to the west, reportedly was used to water
vegetation in a nearby park located north of the site; however, during the March 2021 sampling
event, the property owner informed Terracon that the supply well is inactive and his property has
been connected to municipal water. Well WSW-Cotton Gin, located between 500 and 1,000 feet
east of the source area, is reportedly used for washing vehicles and other machinery. Well
information is summarized in Table 2. The approximate locations of the identified water supply wells
are shown on Figure 3.

C.5 Surface Water
An unnamed tributary of Buffalo Creek is located approximately 1,100 feet northeast and down-
gradient of the site. Surface waters are depicted on Figure 1.

C.6 Land Use Information
The former gas station site is presently occupied by Cool Cycle, Inc., a motorcycle repair shop. The
front of the property contains the former dispenser island beneath an overhead canopy structure.
Two apparent storage buildings are located at the rear (west) of the property. Terracon was not
provided access to the rear of the property; however, minor oil stains and typical motorcycle repair
operations were observed within the on-site building. The adjoining properties to the east, across
Fallston Road and south are commercial businesses. The adjoining property to the west is
developed as a single-family residence and a storage building. The adjoining property to the north is
a city park. The site and surrounding properties are depicted in Figures 1 and 2.

Lewis Service Station
Fallston, North Carolina
Project Number 71179012A
Incident No. 3701
September 21, 2021

Responsive ■ Resourceful ■ Reliable 7
D. ASSESSMENT INFORMATION
D.1 Site Geology and Hydrogeology
The following resources were reviewed to evaluate site-specific geological and hydrogeological
characteristics.

Lawndale, North Carolina, USGS 7.5-minute topographic map, dated 2002 (Figure 1).
Geologic Map of North Carolina, dated 1985.
The Geology of the Carolinas, Carolina Geological Society Fiftieth Anniversary Volume, edited by
J. Wright Horton, Jr., and Victor A. Zullo, The University of Tennessee Press, dated 1991.
Soil Survey of Cleveland County, North Carolina, US Department of Agriculture, Natural
Resources Conservation Service, Web Soil Survey via the Internet,
http://websoilsurvey.nrcs.usda.gov/app/.

The site is located within the Inner Piedmont Belt of 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.
Underlying bedrock in the site area consists of biotite gneiss and schist.

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 Cleveland County, depicts soils at the site as Cecil-Urban land
complex (CeB).

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 (vadose zone). 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. 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 not evident at the time of our subsurface exploration.
Lewis Service Station
Fallston, North Carolina
Project Number 71179012A
Incident No. 3701
September 21, 2021

Responsive ■ Resourceful ■ Reliable 8
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 an interpreted groundwater flow direction from
topographic data, groundwater is expected to flow to the northeast from the site.

D.2 Treatability Study
Terracon engaged RemRx Remediation to complete a treatability study using on-site groundwater
obtained from MW-1, located within the source area. The groundwater sample was collected on
July 12, 2021 by purging three well volumes via disposable polyethylene bailer from MW-1 and then
collecting the sample into glass-ware provided by RemRx Remediation. The treatability study
performed by RemRx Remediation indicated that iron-activated hydrogen peroxide effectively
degrades EDB as well as other contaminants found at the site (e.g. benzene, naphthalene, etc.) at
relatively modest to higher doses. A solid form of hydrogen peroxide, sodium percarbonate, was
also evaluated and found to be effective in degrading contaminant concentrations. The reaction
kinetics of sodium percarbonate are more efficient at lower pH; as such, an acid buffer may be
necessary to adjust groundwater pH if sodium percarbonate is chosen as a treatment for the site.
The treatability is study is provided in Appendix A.

E. AQUIFER TESTING
To evaluate aquifer properties (i.e., aquifer permeability and the potential suitability of contaminant
migration), slug tests were conducted on July 12, 2021 at three on-site monitoring well locations
(MW-1, MW-3 and MW-5) by introducing a solid slug of known volume into each well and measuring
the resulting change in head following the introduction (i.e., “slug-in”). A Level Troll 700 pressure
transducer was used to monitor the change in head within the wells. The tests continued until well
levels recovered to at least 95 percent of the initial static level within a reasonable time period.
Hydraulic conductivity was then estimated from slug test results using AQTESOLV Pro software.
Terracon’s filed notes are provided in Appendix B. Aquifer slug test summary reports and
AQTESOLV data reports are provided in Appendix C.

Time versus water displacement data collected from slug-in (falling head) and slug-out (rising head)
tests conducted at monitoring wells MW-1, VMW-1, and RW-1 were analyzed using the Bower and
Rice (1976) Slug Test Solution for confined aquifers. The falling and risking head slug tests yielded
the following hydraulic conductivities (K):

Slug Test K (feet/minute)
MW-1 (slug-in) 4.84 x 10-5
MW-1 (slug-out) 1.09 x 10-4
VMW-1 (slug-in) 2.63 x 10-4
VMW-1 (slug-out) 3.57 x 10-4
RW-1 (slug-in) 6.53 x 10-4
RW-1 (slug-out) 1.46 x 10-4
Lewis Service Station
Fallston, North Carolina
Project Number 71179012A
Incident No. 3701
September 21, 2021

Responsive ■ Resourceful ■ Reliable 9

These K values correspond to a range of 46.5 feet per year (ft/yr) to 343 ft/yr with an average of
141.6 ft/yr. This range of hydraulic conductivity values is generally consistent with the more
conductive end of published ranges for silts, which comprise the dominant soil lithologies reported in
the Comprehensive Site Assessment Report completed by Shield in December 1995, which
described the site lithologies as “stiff silty clay grading into heterogenous inorganic micaceous silts.”
In addition, the values are generally consistent with the hydraulic conductivity reported in Shield’s
May 1996 Corrective Action Plan (0.197 ft/day [or 72 ft/yr] based on slug tests of MW-2, MW-3, and
MW-6).
F. GROUNDWATER MODELING
Terracon conducted a fate and transport evaluation of petroleum constituents detected in the on-site
monitoring wells to determine the potential of the constituents to migrate towards nearby water
supply well WSW-Cotton Gin, located approximately 715 feet east of the source area. Historically,
WSW-Cotton Gin has not been sampled as part of the release assessment activities.

Terracon utilized available site-specific data (contaminant concentrations, hydraulic gradient, and
hydraulic conductivity) to simulate natural attenuation and transport of the contaminant plume. The
model simulations to evaluate solute transport was completed using the RBCA Tool Kit for Chemical
Releases® Version 2.6. Two different models were utilized: 1) a model simulating biodegradation
through the use of 1st order decay constants for contaminants of concern (i.e. decay half-lives); and
2) a dispersion only model. As no remediation activities other than the 2016 MMPE event have
taken place at the site, constituent concentrations trends other than EDB at the site have generally
been decreasing since 2013 (as demonstrated by Mann-Kendall statistical analysis; see Figures 6,
7, and 8), and prior sampling has identified sufficient microbial populations to support bioremediation
in the surficial aquifer, Terracon believes the model that simulates biodegradation is more
representative of the actual physical processes occurring at the site. However, the dispersion only
model provides a more conservative risk assessment, as it models the transport of contaminant
concentrations through the surficial aquifer without any degradation. The site-specific parameters
used for the models and a discussion of the results are presented below.

Site Specific Model Inputs (RBCA Tool Kit)
Terracon utilized site-specific hydraulic conductivity data from the slug testing performed by
Terracon in July 2021. The average hydraulic conductivity was estimated at 141.6 ft/yr for the site
and was used in the model simulation. The average hydraulic gradient, 0.0013 ft/ft, was estimated
for the site based on the historic groundwater elevations. Using an estimated porosity of 0.35, the
seepage velocity used by the model was calculated as approximately 4.6 feet per year. Site specific
data for soil bulk density, the partition coefficient, and fraction organic carbon were not available so
the default values were used in the model simulation. As depth to water in the source area typically
ranges from approximately 20 to 25 feet bls and a “semi-competent” formation was described in the
boring logs for VMW-1 from approximately 40 to 45 feet, the plume thickness at the source area was
estimated to be approximately 30 feet by assuming that this apparent partially weather rock zone
Lewis Service Station
Fallston, North Carolina
Project Number 71179012A
Incident No. 3701
September 21, 2021

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extended approximately 5 additional feet (50 feet bls) prior to the occurrence of bedrock. As the
Mann Kendall statistical results (see Figures 6, 7, and 8) indicate the plume is shrinking, the highest
concentrations of benzene, toluene, ethylbenzene, total xylenes, EDB, and MTBE identified within
MW-1, VMW-1, and RW-1 were used as the contaminant concentrations in the source area. The
data and inputs used for the model are indicated on the input screen included in Appendix D.

Biodegradation Model Results
According to the RBCA Tool Kit®, biodegradation is simulated as a first-order decay process. For
the biodegradation model, the most conservative half-lives for each constituent published in The
Handbook of Environmental Degradation Rates (Howard et al., 1991) were utilized. The
biodegradation model indicates that concentrations of the contaminants of concern in excess of the
calculated concentrations limits never reach the point of exposure (e.g. WSW -Cotton Gin). The
steady-state concentrations calculated to exist at the point of exposure range from 1.9 x 10-9 µg/L
(benzene) to 1.2 x10-63 µg/L (toluene). The calculated total carcinogenic risk (4.1 x 10-16) and hazard
index (3.0 x 10-11) for the point of exposure are many orders of magnitude lower than NCDEQ’s
acceptable risk tolerances of 1.0 x 10-4 and 1, respectively.

Dispersion Only Model Results
According to the RBCA Tool Kit®, the dispersion only model uses the steady-state Domenico
analytical solute transport model to account for dispersion between the groundwater source zone
and off-site receptor locations but does not account for biodegradation effects (a first-order decay
process). While biodegradation may be occurring within the sub-surface, exclusion of
biodegradation in the model provides a more conservative modeled result for concentrations at the
point of exposure. The dispersion only model results indicate that WSW-Cotton Gin is highly unlikely
to become impacted by the petroleum concentrations currently detected at the site. The model
calculates that benzene, toluene, ethylbenzene, total xylene, and MTBE will never reach the
calculated concentration limit at the point of exposure. While the model indicates that EDB would
reach its concentration limit at the point of exposure (calculated as 0.34 µg/L; the RBCA Toolkit®
does not allow for manually entering the 2L standard of 0.02 µg/L for the point of exposure
concentration limit) after 123.1 years, it must be noted that the calculated total carcinogenic risk
(7.2 x 10-5) and hazard index (0.31) for the point of exposure are lower than NCDEQ’s acceptable
risk tolerances of 1.0 x 10-4 and 1, respectively.

Summaries of the model results are provided in Appendix D. As the more conservative, dispersion
only model indicates minimal risk to WSW-Cotton Gin, and the more realistic model that includes
biodegradation indicates virtually zero risk to WSW-Cotton Gin, it does not appear likely that the on-
site contaminant concentrations will impact the water supply well in the future. As such, the site’s
remediation targets can be set as the GCLs rather than the 2L standards.
Lewis Service Station
Fallston, North Carolina
Project Number 71179012A
Incident No. 3701
September 21, 2021

Responsive ■ Resourceful ■ Reliable 11
G. CONCLUSIONS AND RECOMMENDATIONS
Based on information obtained during the completion of these assessment activities, Terracon
provides the following conclusions and findings.

Iron-activated hydrogen peroxide can effectively degrade EDB as well as other contaminants found
at the site (e.g. benzene, naphthalene, etc.) at relatively modest to higher doses. A solid form of
hydrogen peroxide, sodium percarbonate, was also evaluated and found to be effective in
degrading contaminant concentrations. The reaction kinetics of sodium percarbonate are more
efficient at lower pH; as such, an acid buffer may be necessary to adjust groundwater pH if sodium
percarbonate is chosen as a treatment for the site.
Aquifer testing (slug-in and slug-out tests) of the three source area wells (MW-1, VMW-1, and
RW-1) yielded hydraulic conductivity values in the range of 46.5 feet per year (ft/yr) to 343 ft/yr with
an average of 141.6 ft/yr. This range of hydraulic conductivity values is generally consistent with
the more conductive end of published ranges for silts, which comprise the dominant soil lithologies
reported in the Comprehensive Site Assessment Report completed by Shield in December 1995,
which described the site lithologies as “stiff silty clay grading into heterogenous inorganic
micaceous silts.” In addition, the values are generally consistent with the hydraulic conductivity
reported in Shield’s May 1996 Corrective Action Plan (0.197 ft/day [or 72 ft/yr] based on slug tests
of MW-2, MW-3, and MW-6).
Contaminant fate and transport modeling using steady-state Domenico analytical solute transport
models to account for either biodegradation (1st order decay) or dispersion only scenarios both
indicate minimal risk that on-site contaminant concentrations are likely to impact WSW-Cotton Gin
in the future. Based on the model results, the site remediation targets can be set as the GCLs
rather than 2L standards.
Based on the findings of our assessment activities, the following comments and recommendations are
provided for the site.
Terracon recommends coordinating with RemRx Remediation to determine the proper dosing of
hydrogen peroxide or sodium percarbonate necessary to reduce site contaminants to below their
GCLs. The remediation compounds would be emplaced within augered boreholes located within
the source zone.
Following the installation of the remediation compound(s), semi-annual monitoring at the site
should be completed to demonstrate that concentrations have been reduced to and remain below
their GCLs. Once this can be demonstrated, the site would then be eligible for closure with
issuance of a Notice of Residual Petroleum (NORP).

FIGURES

SITE LOCATION MAP
Lewis Service Station (Incident No. 3701)
4733 Fallston Road Fallston, Cleveland County, NC
TOPOGRAPHIC MAP IMAGE COURTESY OF THE U.S. GEOLOGICAL SURVEY
QUADRANGLES INCLUDE: LAWNDALE, NC (1/1/2002) and CHERRYVILLE, NC (1/1/2003).
2701 Westport Road
Charlotte, NC 28208
71179012A
Project Manager:
Drawn by:
Checked by:
Approved by:
WOF
CLC
CLC
1”=2,000’
71179012.1
March 2021
Project No.
Scale:
File Name:
Date: 1
Figure WOF
APPROXIMATE
SITE BOUNDARY
2
Figure
DIAGRAM IS FOR GENERAL LOCATION ONLY,
AND IS NOT INTENDED FOR CONSTRUCTION
PURPOSES 2701 Westport Road
Charlotte, NC
Site PlanProject Manager:
Drawn by:
Checked by:
Approved by:
WOF Project No.
File Name:
Date:
Scale:
71179012A
WOF
Sept. 2021MNM
MNM 71179012.2
Lewis Service Station (Incident #3701)
4733 Fallston Road
Fallston, Cleveland County, North Carolina
denotes approximate site
boundary
denotes groundwater
monitoring well.
denotes water
supply well
WSW-4
Not Sampled
1” = 35 ft.
MW-5
Stamey Store
Incident No. 12004
Canopy
MW-4
MW-6
MW-3
MW-2
Not Sampled
Former
WSW-3
Former
WSW-2
MW-7MW-8
Not Sampled NC HIGHWAY 18denotes approximate fence line
Shed
Shed
Cool Cycle, Inc. VMW-1
RW-1
SVE-1
MW-1
Former 1,000-gallon
gasoline USTs
Former 1,000-gallon
gasoline USTs
(abandoned in place)
Former 1,000-gallon
kerosene UST 550-gallon gasoline
USTs (not in use)
SSMW-2
Not Sampled
WATER SUPPLY WELL LOCATION MAP
2701 Westport Road
Charlotte, NC 28208
DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS
NOT INTENDED FOR CONSTRUCTION PURPOSES
3
Figure
denotes water supply well
1,500 ft. Radius
(from release location)
1,000 ft. Radius
(from release location)
500 ft. Radius
(from release location)
Lewis Service Station (Incident #3701)
4733 Fallston Road
Fallston, Cleveland County, North Carolina
Project Manager:
Drawn by:
Checked by:
Approved by:
WOF
Project No.
File Name:
Date:
Scale:
71179012A
WOF
CLC Sept. 2021
CLC
1”~ 375’
71179012.3
WSW-4
WSW Cotton Gin
4
Figure
DIAGRAM IS FOR GENERAL LOCATION ONLY,
AND IS NOT INTENDED FOR CONSTRUCTION
PURPOSES Charlotte, NC
Groundwater Elevation Map (March 2021)Project Manager:
Drawn by:
Checked by:
Approved by:
WOF Project No.
File Name:
Date:
Scale:
71179012A
WOF
Sept. 2021MNM
MNM 71179012.4
Lewis Service Station (Incident #3701)
4733 Fallston Road
Fallston, Cleveland County, North Carolina
denotes approximate site
boundary
denotes groundwater
monitoring well.
denotes water
supply well
WSW-4
1” = 35 ft.
MW-5
Stamey Store
Incident No. 12004
Canopy
MW-4
MW-6
MW-3
MW-2
Former
WSW-3
Former
WSW-2
MW-8 NC HIGHWAY 18denotes approximate fence line
Shed
Shed
Cool Cycle, Inc. VMW-1
RW-1
SVE-1
MW-1
Former 1,000-gallon
gasoline USTs
Former 1,000-gallon
gasoline USTs
(abandoned in place)
Former 1,000-gallon
kerosene UST 550-gallon gasoline
USTs (not in use)
MW-7
SSMW-2
79.67
78.83
77.26
80.45
79.27
79.49
79.48
2701 Westport Road
77’
80’78’
79’
5
Figure
DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES 2701 Westport Road
Charlotte, NC
Groundwater Analytical Results (March 2021)Project Manager:
Drawn by:
Checked by:
Approved by:
WOF Project No.
File Name:
Date:
Scale:
71179012A
WOF
Sept. 2021MNM
MNM 71179012.5
Lewis Service Station (Incident #3701)
4733 Fallston Road
Fallston, Cleveland County, North Carolina
denotes approximate site
boundary
denotes groundwater
monitoring well.
denotes water
supply well
WSW-4
1” = 35 ft.
MW-5
Canopy
MW-4
MW-6
MW-3
MW-2
Not Sampled
Former
WSW-3
Former
WSW-2
MW-7MW-8
Not Sampled NC HIGHWAY 18denotes approximate fence line
Shed
Shed
Cool Cycle, Inc. SVE-1
Former 1,000-gallon
gasoline USTs
550-gallon gasoline USTs (not in use)
Sample ID: RW-1Groundwater Sample6200 –Benzene: 124 µg/LEDB: 3.5 µg/L1,2-Dichloroethane: 3.3 µg/LDiisopropyl ether: 1.6 J µg/LEthylbenzene: 142 µg/L
Isopropylbenzene: 23.8 µg/LMTBE: 45.1 µg/LNaphthalene: 72.7 µg/L
n-Propylbenzene: 55 µg/L
Toluene: 52.9 µg/L1,2,4-Trimethylbenzene: 574 µg/L
1,3,5-Trimethylbenzene: 109 µg/L
Total Xylenes: 104 µg/L
*Values above 2L Standards are in bold.
Sample ID: VMW-1
Groundwater Sample
6200 –Benzene: 79 µg/L
sec-Butylbenzene: 5.3 µg/L
1,2-Dichloroethane: 5.2 µg/L
Diisopropyl ether: 3.2 µg/L
Ethylbenzene: 104 µg/L
Isopropylbenzene: 22.5 µg/L
MTBE: 131 µg/L
Naphthalene: 7 µg/L
n-Propylbenzene: 37.1 µg/L
Toluene: 1.5 µg/L
1,2,4-Trimethylbenzene: 278 µg/L
*Values above 2L Standards are in bold.
Sample ID: MW-1
Groundwater Sample
6200 –Benzene: 317 µg/L
EDB: 73.7 µg/L
1,2-Dichloroethane: 11 µg/L
Ethylbenzene: 330 µg/L
Isopropylbenzene: 39.5 µg/L
MTBE: 82.9 µg/L
Naphthalene: 429 µg/L
Toluene: 2,390 µg/L
1,2,4-Trimethylbenzene: 1,550 µg/L
Total Xylenes: 4,030 µg/L
*Values above 2L Standards are in bold.
**Values above GCL Standards are in italics
SSMW-2
Not Sampled
Sample ID: MW-7
Groundwater Sample6200 –Compounds Not Detected above MDLs
Sample ID: MW-4
Groundwater Sample
6200 –Compounds Not Detected above MDLs
Sample ID: MW-5
Groundwater Sample
6200 –Compounds Not Detected above MDLs
Sample ID: MW-6
Groundwater Sample
6200 –Compounds Not Detected above MDLs
Sample ID: MW-3
Groundwater Sample
6200 –Compounds Not Detected above MDLs
Figure 6
Benzene Concentration vs. Time Trend Analysis
Evaluation Date:Job ID:
Facility Name:Constituent:
Conducted By:Concentration Units:µg/L
Sampling Point ID:MW-1 VMW-01 RW-1
Sampling Sampling
Event Date
1 6/11/2013 4040 1530 8,280
2 11/13/13 6,890 2660 7,340
3 04/24/14 179 3400 4,320
4 05/29/15 850 4880 5,460
5 11/24/15 2,200 1290 6,750
6 06/14/16 580 2840 2,670
7 08/15/17 1,800 2400 5,900
8 07/29/19 509 270 464
9 03/10/21 317 79 124
10
11
12
13
14
15
16
17
18
19
20
Coefficient of Variation:1.34 0.73 0.67
Mann-Kendall Statistic (S):-10 -16 -16
Confidence Factor:86.2%96.9%96.9%
Concentration Trend:No Trend Decreasing Decreasing
Notes:
1.At least four independent sampling events per well are required for calculating the trend. Methodology is valid for 4 to 40 samples.
2.Confidence in Trend = Confidence (in percent) that constituent concentration is increasing (S>0) or decreasing (S<0): >95% = Increasing or Decreasing;
≥ 90% = Probably Increasing or Probably Decreasing; < 90% and S>0 = No Trend; < 90%, S≤0, and COV ≥ 1 = No Trend; < 90% and COV < 1 = Stable.
3.Methodology based on "MAROS: A Decision Support System for Optimizing Monitoring Plans", J.J. Aziz, M. Ling, H.S. Rifai, C.J. Newell, and J.R. Gonzales,
Ground Water, 41(3):355-367, 2003.
4..-- Indicates date not sampled/well non-existent.
5.The laboratory reporting limit was entered when the laboratory did not detect concentrations above the reporting limit.
DISCLAIMER: The GSI Mann-Kendall Toolkit is available "as is". Considerable care has been exercised in preparing this software product; however, no party, including without
limitation GSI Environmental Inc., makes any representation or warranty regarding the accuracy, correctness, or completeness of the information contained herein, and no such
party shall be liable for any direct, indirect, consequential, incidental or other damages resulting from the use of this product or the information contained herein. Information in
this publication is subject to change without notice. GSI Environmental Inc., disclaims any responsibility or obligation to update the information contained herein.
BENZENE CONCENTRATION (µg/L)
GSI Environmental Inc., www.gsi-net.com
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
09/16/21 71179012A
Lewis Service Station (Incident #3701)Benzene
Terracon
1
10
100
1000
10000
04/12 08/13 12/14 05/16 09/17 02/19 06/20 10/21Concentration (µg/L)Sampling Date
MW-1
VMW-01
RW-1
Figure 7
EDB Concentration vs. Time Trend Analysis
Evaluation Date:Job ID:
Facility Name:Constituent:
Conducted By:Concentration Units:µg/L
Sampling Point ID:MW-1
Sampling Sampling
Event Date
1 6/11/2013 7.4
2 11/13/13 7.4
3 04/24/14 7.4
4 05/29/15 7.4
5 11/24/15 18.1
6 06/14/16 7.4
7 08/15/17 7.4
8 07/29/19 57.6
9 03/10/21 73.7
10
11
12
13
14
15
16
17
18
19
20
Coefficient of Variation:1.15
Mann-Kendall Statistic (S):14
Confidence Factor:94.6%
Concentration Trend:Prob. Increasing
Notes:
1.At least four independent sampling events per well are required for calculating the trend. Methodology is valid for 4 to 40 samples.
2.Confidence in Trend = Confidence (in percent) that constituent concentration is increasing (S>0) or decreasing (S<0): >95% = Increasing or Decreasing;
≥ 90% = Probably Increasing or Probably Decreasing; < 90% and S>0 = No Trend; < 90%, S≤0, and COV ≥ 1 = No Trend; < 90% and COV < 1 = Stable.
3.Methodology based on "MAROS: A Decision Support System for Optimizing Monitoring Plans", J.J. Aziz, M. Ling, H.S. Rifai, C.J. Newell, and J.R. Gonzales,
Ground Water, 41(3):355-367, 2003.
4..-- Indicates date not sampled/well non-existent.
5.The laboratory reporting limit was entered when the laboratory did not detect concentrations above the reporting limit.
DISCLAIMER: The GSI Mann-Kendall Toolkit is available "as is". Considerable care has been exercised in preparing this software product; however, no party, including without
limitation GSI Environmental Inc., makes any representation or warranty regarding the accuracy, correctness, or completeness of the information contained herein, and no such
party shall be liable for any direct, indirect, consequential, incidental or other damages resulting from the use of this product or the information contained herein. Information in
this publication is subject to change without notice. GSI Environmental Inc., disclaims any responsibility or obligation to update the information contained herein.
EDB CONCENTRATION (µg/L)
GSI Environmental Inc., www.gsi-net.com
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
09/16/21 71179012A
Lewis Service Station (Incident #3701)EDB
Terracon
1
10
100
04/12 08/13 12/14 05/16 09/17 02/19 06/20 10/21Concentration (µg/L)Sampling Date
MW-1
MW-1
Figure 8
MTBE Concentration vs. Time Trend Analysis
Evaluation Date:Job ID:
Facility Name:Constituent:
Conducted By:Concentration Units:µg/L
Sampling Point ID:MW-1 VMW-01 RW-1
Sampling Sampling
Event Date
1 6/11/2013 19800 16000 26,900
2 11/13/13 8,150 17100 20,700
3 04/24/14 146 14400 8,770
4 05/29/15 1,020 13600 8,290
5 11/24/15 2,640 16300 13,500
6 06/14/16 245 12200 3,090
7 08/15/17 1,000 14000 5,800
8 07/29/19 191 1060 217
9 03/10/21 83 131 45
10
11
12
13
14
15
16
17
18
19
20
Coefficient of Variation:1.63 0.60 0.93
Mann-Kendall Statistic (S):-14 -20 -22
Confidence Factor:94.6%99.3%99.8%
Concentration Trend:Prob. Decreasing Decreasing Decreasing
Notes:
1.At least four independent sampling events per well are required for calculating the trend. Methodology is valid for 4 to 40 samples.
2.Confidence in Trend = Confidence (in percent) that constituent concentration is increasing (S>0) or decreasing (S<0): >95% = Increasing or Decreasing;
≥ 90% = Probably Increasing or Probably Decreasing; < 90% and S>0 = No Trend; < 90%, S≤0, and COV ≥ 1 = No Trend; < 90% and COV < 1 = Stable.
3.Methodology based on "MAROS: A Decision Support System for Optimizing Monitoring Plans", J.J. Aziz, M. Ling, H.S. Rifai, C.J. Newell, and J.R. Gonzales,
Ground Water, 41(3):355-367, 2003.
4..-- Indicates date not sampled/well non-existent.
5.The laboratory reporting limit was entered when the laboratory did not detect concentrations above the reporting limit.
DISCLAIMER: The GSI Mann-Kendall Toolkit is available "as is". Considerable care has been exercised in preparing this software product; however, no party, including without
limitation GSI Environmental Inc., makes any representation or warranty regarding the accuracy, correctness, or completeness of the information contained herein, and no such
party shall be liable for any direct, indirect, consequential, incidental or other damages resulting from the use of this product or the information contained herein. Information in
this publication is subject to change without notice. GSI Environmental Inc., disclaims any responsibility or obligation to update the information contained herein.
MTBE CONCENTRATION (µg/L)
GSI Environmental Inc., www.gsi-net.com
GSI MANN-KENDALL TOOLKIT
for Constituent Trend Analysis
09/16/21 71179012A
Lewis Service Station (Incident #3701)MTBE
Terracon
1
10
100
1000
10000
100000
04/12 08/13 12/14 05/16 09/17 02/19 06/20 10/21Concentration (µg/L)Sampling Date
MW-1
VMW-01
RW-1

TABLES
TABLE 1
Historical UST Information
Lewis Service Station
Fallston, North Carolina
Terracon Project No. 71179012A
NCDEQ Incident No. 3701
Contents Capacity (gallons)Date Installed Date Closed Closed/Active Release from
System
Gasoline 1,000 Unknown Unknown Abandoned in place Yes
Gasoline 1,000 Unknown Unknown Abandoned in place No
Kerosene 1,000 Unknown Unknown Removed No
TABLE 2
Water Supply Well Information
Lewis Service Station
Fallston, North Carolina
Terracon Project No. 71179012A
NCDEQ Incident No. 3701
Well ID Property Owner Property Address Mailing Address Distance/Direction from
source area (in feet)Well Status/Use Parcel No.Notes
WSW-4 Claude & Neveen Falls 772 East Stage Coach Trail
Fallston, NC
PO Box 1632
Lincolnton, NC 28092 170 ft / west Inactive 34672 Property connected to municipal water
WSW-Cotton Gin John & Ashley Herndon 815 East Stage Coach Tail
Fallston, NC
PO Box 652
Fallston, NC 28042 715 ft / east Active 34559 Used for cleaning vehicles
TABLE 3
Summary of Groundwater Analytical Results
Lewis Service Station
Fallston, North Carolina
Terracon Project No. 71179012A
NCDEQ Incident No. 3701
Contaminant of Concern →
Well/Sample
I.D.
Date Collected
(mm/dd/yy)
4/21/1995 7000 NR NR NR NR NR 19000 2400 12000 10000 720 NA 150 NR NR 200 ND
10/11/1995 17000 NR NR NR NR NR 41000 2800 18000 19000 1000 NA 820 NR NR 340 ND
9/2/1999
3/8/2000
8/27/2001
2/22/2002
8/6/2002
2/12/2003
8/5/2003 2800 NR NR NR NR NR 10000 1200 12700 13000 ND NA ND NR NR ND ND
7/6/2012 6680 NR NR NR NR NR 19500 1910 14630 16600 198 467 193 NR NR 32.8 ND
12/27/2012
6/11/2013 4040 NR NR NR NR NR 6200 1020 12030 19800 311 706 276 NR NR ND ND
11/13/2013 6890 NR NR NR NR NR 2420 1170 9230 8150 168 751 172 NR NR ND ND
4/24/2014 179 NR NR NR NR NR 542 206 1343 146 ND 179 ND NR NR ND ND
5/29/2015 850 NR NR NR NR NR 5520 670 5620 1020 23.1 420 33.1 NR NR 18.1 ND
11/24/2015 2200 NR NR NR NR NR 2520 1190 7130 2640 57.4 545 66.3 NR NR ND ND
6/14/2016 580 NR NR NR NR NR 309 410 1388 245 9 174 10.9 NR NR 12.2 ND
8/15/2017 1800 46 24 110 16 290 1500 1200 3800 1000 46 430 63 3100 830 <7.4 ND
7/29/2019 509 <6.2 <6.2 41.9 NR 109 2750 362 3190 191 8.5J 387 <6.2 1640 415 57.6 ND
3/10/2021 317 <9.8 <8.0 39.5 NR <6.8 2390 330 4030 82.9 <6.2 429 11 1550 <6.6 73.7 <33.2
4/21/1995 2 NR NR NR NR NR 5 ND 13 ND 1.2 NA ND NR NR ND ND
10/11/1995 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
9/2/1999 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR NA ND
3/8/2000 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/27/2001 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR NA ND
2/22/2002
8/6/2002
2/12/2003 ND NR NR NR NR NR 3.3 1.3 4.8 ND ND ND ND NR NR ND ND
8/5/2003 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
7/6/2012 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/15/2017
7/29/2019 <0.25 <0.25 <0.25 <0.25 NR <0.25 <0.25 <0.25 <0.50 0.47J <0.25 <1.0 <0.25 <0.25 <0.25 <0.25 3.6J
3/10/2021
4/21/1995 58 NR NR NR NR NR 7.2 13 27 1100 17 NA ND NR NR 0.1 ND
10/11/1995 93 NR NR NR NR NR 4.7 21 36 710 20 NA 1.1 NR NR 0.08 ND
9/2/1999 12 NR NR NR NR NR ND ND 11 360 25 ND NA NR NR NA ND
3/8/2000 14 NR NR NR NR NR ND 5 8.4 170 14 ND ND NR NR ND ND
8/27/2001 14 NR NR NR NR NR 18 10 21.9 110 3.3 22 ND NR NR NA ND
2/22/2002 50 NR NR NR NR NR ND 13 18.3 81 ND ND ND NR NR ND ND
8/6/2002
2/12/2003 1.8 NR NR NR NR NR 1.2 1.8 ND 38 ND ND ND NR NR NA ND
8/5/2003 ND NR NR NR NR NR ND ND ND 53 1.3 ND ND NR NR ND ND
7/6/2012 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/15/2017
7/29/2019 <0.25 <0.25 <0.25 <0.25 NR <0.25 <0.25 <0.25 <0.50 <0.25 <0.25 <1.0 <0.25 <0.25 <0.25 <0.25 <2.5
3/10/2021 <0.34 <0.49 <0.40 <0.33 NR <0.34 <0.48 <0.30 <0.71 <0.42 <0.31 <0.64 <0.32 <0.50 <0.33 <0.27 <1.7
10/11/1995 ND NR NR NR NR NR 3.7 ND ND 1.2 ND NA ND NR NR ND ND
9/2/1999 ND NR NR NR NR NR ND ND ND ND ND ND NA NR NR NA ND
3/8/2000 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/27/2001 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR NA ND
2/22/2002
8/6/2002
2/12/2003 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/5/2003 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
7/6/2012 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/15/2017
7/29/2019 <0.25 <0.25 <0.25 <0.25 NR <0.25 <0.25 <0.25 <0.50 <0.25 <0.25 <1.0 <0.25 <0.25 <0.25 <0.25 <2.5
3/10/2021 <0.34 <0.49 <0.40 <0.33 NR <0.34 <0.48 <0.30 <0.71 <0.42 <0.31 <0.64 <0.32 <0.50 <0.33 <0.27 <1.7
10/11/1995 ND NR NR NR NR NR ND ND ND 2 ND NA ND NR NR ND ND
9/2/1999 ND NR NR NR NR NR ND ND ND ND ND ND NA NR NR NA ND
3/8/2000 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/27/2001 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR NA ND
2/22/2002 5.2 NR NR NR NR NR ND ND 3 ND ND ND ND NR NR ND ND
8/6/2002 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
2/12/2003 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/5/2003 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
7/6/2012 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/15/2017
7/29/2019 <0.25 <0.25 <0.25 <0.25 NR <0.25 <0.25 <0.25 <0.50 <0.25 <0.25 <1.0 <0.25 <0.25 <0.25 <0.25 <2.5
3/10/2021 <0.34 <0.49 <0.40 <0.33 NR <0.34 <0.48 <0.30 <0.71 <0.42 <0.31 <0.64 <0.32 <0.50 <0.33 <0.27 <1.7
MW-1
MW-2
Not Sampled
MW-3
MW-4
MW-5 1,3,5-TrimethylbenzeneDiisopropyl EtherEthylbenzeneTotal XylenesNot Sampled
Not Sampled - Dry
Not Sampled
Not Sampled - Dry EDBTolueneAnalytical Method
BenzeneNot Sampled - Dry BromomethaneNot Sampled
6200B
Not Sampled
Not Sampled - Dry
Not Sampled 1,2-DichloroethaneNaphthaleneNot Sampled
Not Sampled MTBEn-Butylbenzenesec-ButylbenzeneIsopropylbenzenep-Isopropyltoluenen-Propylbenzene1,2,4-Trimethylbenzene
TABLE 3
Summary of Groundwater Analytical Results
Lewis Service Station
Fallston, North Carolina
Terracon Project No. 71179012A
NCDEQ Incident No. 3701
Contaminant of Concern →
Well/Sample
I.D.
Date Collected
(mm/dd/yy)
MW-1 1,3,5-TrimethylbenzeneDiisopropyl EtherEthylbenzeneTotal XylenesEDBTolueneAnalytical Method
BenzeneBromomethane6200B
1,2-DichloroethaneNaphthaleneMTBEn-Butylbenzenesec-ButylbenzeneIsopropylbenzenep-Isopropyltoluenen-Propylbenzene1,2,4-Trimethylbenzene10/11/1995 450 NR NR NR NR NR 7.6 36 180 ND 4.3 NA 28 NR NR ND ND
9/2/1999 19 NR NR NR NR NR ND ND 13 ND ND ND NA NR NR ND ND
3/8/2000 15 NR NR NR NR NR ND ND 16.2 ND 1.3 ND 7.6 NR NR ND ND
8/27/2001 27 NR NR NR NR NR ND ND 24 ND 1.4 ND 8.3 NR NR ND ND
2/22/2002 23 NR NR NR NR NR ND ND 24 ND 1.6 ND 9.6 NR NR ND ND
8/6/2002
2/12/2003 12 NR NR NR NR NR 1 1.7 13 ND ND ND 5.8 NR NR ND ND
8/5/2003 17 NR NR NR NR NR ND 1.5 17.4 ND ND ND 4 NR NR ND ND
7/6/2012 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/15/2017
7/29/2019 <0.25 <0.25 <0.25 <0.25 NR <0.25 <0.25 <0.25 <0.50 <0.25 <0.25 <1.0 <0.25 <0.25 <0.25 <0.25 <2.5
3/10/2021 <0.34 <0.49 <0.40 <0.33 NR <0.34 <0.48 <0.30 <0.71 <0.42 <0.31 <0.64 <0.32 <0.50 <0.33 <0.27 <1.7
10/11/1995 ND NR NR NR NR NR ND ND ND ND ND NA ND NR NR ND ND
9/2/1999
3/8/2000
8/27/2001
2/22/2002
8/6/2002
2/12/2003
8/5/2003 ND NR NR NR NR NR ND ND ND ND ND NA ND NR NR ND ND
7/6/2012
8/15/2017
7/29/2019
3/10/2021 <0.34 <0.49 <0.40 <0.33 NR <0.34 <0.48 <0.30 <0.71 <0.42 <0.31 <0.64 <0.32 <0.50 <0.33 <0.27 <1.7
10/11/1995 ND NR NR NR NR NR 7 ND 1.8 ND ND NA ND NR NR ND ND
9/2/1999 ND NR NR NR NR NR ND ND ND ND ND ND NA NR NR NA ND
8/27/2001 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR NA ND
2/22/2002
8/6/2002
2/12/2003
8/5/2003 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
7/6/2012 ND NR NR NR NR NR ND ND ND ND ND ND ND NR NR ND ND
8/15/2017
7/29/2019 <0.25 <0.25 <0.25 <0.25 NR <0.25 <0.25 <0.25 <0.50 <0.25 <0.25 <1.0 <0.25 <0.25 <0.25 <0.25 <2.5
3/10/2021
MW-6
MW-7
MW-8
Not Sampled
Not Sampled - Well Obstructed
Not Sampled
Not Sampled
Not Sampled - Dry
Not Sampled
Not Sampled - Dry
Not Sampled
Not Sampled
Not Sampled - Dry
Not Sampled - Dry
TABLE 3
Summary of Groundwater Analytical Results
Lewis Service Station
Fallston, North Carolina
Terracon Project No. 71179012A
NCDEQ Incident No. 3701
Contaminant of Concern →
Well/Sample
I.D.
Date Collected
(mm/dd/yy)
MW-1 1,3,5-TrimethylbenzeneDiisopropyl EtherEthylbenzeneTotal XylenesEDBTolueneAnalytical Method
BenzeneBromomethane6200B
1,2-DichloroethaneNaphthaleneMTBEn-Butylbenzenesec-ButylbenzeneIsopropylbenzenep-Isopropyltoluenen-Propylbenzene1,2,4-Trimethylbenzene10/11/1995 2.8 NR NR NR NR NR 3.4 ND 1.5 2.1 ND NA ND NR NR 0.19 ND
8/27/2001 130 NR NR NR NR NR 48 24 168 27 3.5 4.4 15 NR NR NA ND
2/22/2002 490 NR NR NR NR NR ND ND 207 330 ND ND 22 NR NR ND ND
8/6/2002 4100 NR NR NR NR NR 3100 460 2400 5400 87 150 180 NR NR 29 ND
2/12/2003 1800 NR NR NR NR NR 26 ND 170 690 ND 61 85 NR NR ND ND
8/5/2003 1300 NR NR NR NR NR 130 76 1410 2000 54 120 80 NR NR ND ND
7/6/2012 7250 NR NR NR NR NR 43 831 1321 24900 337 418 422 NR NR ND ND
12/27/2012 2170 NR NR NR NR NR ND ND ND 17200 363 ND 520 NR NR ND ND
6/11/2013 1530 NR NR NR NR NR ND ND ND 16000 355 ND 479 NR NR ND ND
11/13/2013 2660 NR NR NR NR NR 93.3 75.3 335 17100 293 ND 361 NR NR ND ND
4/24/2014 3400 NR NR NR NR NR 332 205 756 14400 279 ND 305 NR NR ND ND
5/29/2015 4480 NR NR NR NR NR ND 462 521 13600 235 545 259 NR NR ND ND
11/24/2015 1290 NR NR NR NR NR ND ND ND 16300 306 ND 350 NR NR ND ND
6/14/2016 2840 NR NR NR NR NR ND 112 243 12200 233 217 236 NR NR ND ND
8/15/2017 2400 <30 <26 58 <30 48 <34 210 140 14000 340 310 380 270 130 <30 ND
7/29/2019 270 <0.25 <0.25 11.7 NR 14.3 <0.25 72.7 <0.50 1060 21.2 91.0 23.1 177 <0.25 <0.25 <2.5
3/10/2021 79 <0.98 5.3 22.5 NR 37.1 1.5 104 <1.4 131 3.2 7 5.2 278 <0.66 <0.54 <3.3
2/22/2002 7700 NR NR NR NR NR 14000 1400 7400 12000 ND ND 360 NR NR ND ND
8/6/2002 12000 NR NR NR NR NR 20000 2400 8700 17000 260 400 400 NR NR 77 ND
2/12/2003 7100 NR NR NR NR NR 8400 980 6100 6200 ND 280 250 NR NR ND ND
8/5/2003 3700 NR NR NR NR NR 4100 1400 8200 11000 ND ND 190 NR NR ND ND
7/6/2012 7310 NR NR NR NR NR 2970 2340 7390 23700 240 612 298 NR NR ND ND
12/27/2012 6470 NR NR NR NR NR 1360 1310 6810 21000 229 584 289 NR NR ND ND
6/11/2013 8280 NR NR NR NR NR 668 1360 4940 26900 401 568 353 NR NR ND ND
11/13/2013 7340 NR NR NR NR NR 669 1330 5110 20700 279 528 309 NR NR ND ND
4/24/2014 4320 NR NR NR NR NR 265 857 2750 8770 159 430 134 NR NR ND ND
5/29/2015 5460 NR NR NR NR NR 608 1240 3410 8290 151 662 185 NR NR ND ND
11/24/2015 6750 NR NR NR NR NR 287 860 3470 13500 246 452 215 NR NR ND ND
6/14/2016 2670 NR NR NR NR NR 234 804 1938 3090 78.8 412 67.1 NR NR ND ND
8/15/2017 5900 <15 13 79 <15 170 160 1100 1940 5800 190 490 200 1900 460 <15 ND
7/29/2019 464 <0.25 <0.25 41.8 NR 107 135 335 499 217 7.8 226 6.9 1030 269 8.5 <2.5
3/10/2021 124 <2 <1.6 23.8 NR 55 52.9 142 104 45.1 1.6 J 72.7 3.3 574 109 3.5 <6.6
WSW-4 7/29/2019 <0.25 <0.25 <0.25 <0.25 NR <0.25 <0.25 <0.25 <0.50 <0.25 <0.25 <1.0 <0.25 <0.25 <0.25 <0.25 <2.5
SSMW-2 7/29/2019 4.9 <0.25 <0.25 <0.25 NR <0.25 <0.25 <0.25 <0.50 151 1.9 <1.0 5.2 <0.25 <0.25 <0.25 <2.5
1 70 70 70 25 70 600 600 500 20 70 6 0.4 400 400 0.02 10
5,000 6,900 8,500 25,000 11,700 30,000 260,000 84,500 85,500 20,000 70,000 6,000 400 28,500 25,000 50 10,000
Notes:
µg/L = Micrograms per liter
NA = Not analyzed
ND = Not detected at or above laboratory reporting limits.
NR=Not Reported
Contaminants that exceed the NCDEQ - NCAC 15A 2L Groundwater Standards are in BOLD.
GCL = Gross contamination levels for groundwater
VMW-1
RW-1
Contaminants that exceed their GCL are highlighted in yellow.
2L Standard (ug/L)GCL (ug/L)
TABLE 4
Monitoring Well Construction Information
and Historical Groundwater Elevations
Lewis Service Station
Fallston, North Carolina
Terracon Project No. 71179012A
NCDEQ Incident No. 3701
Well Id
Date
Installed
(mm/dd/yy)
Date Water
Level Measured
(mm/dd/yy)
Well Casing
Diameter
(in.)
Screen
Interval (ft-
TOC)
Depth of
Well
(ft-TOC)
Top of Casing
Elevation (ft.)
Depth to Water from
Top of Casing
(ft.)
Groundwater
Elevation (ft.)Comments
3/8/2000 25.16 72.46
8/27/2001 26.63 70.99
2/22/2001
8/6/2002
2/12/2003 27.14 70.48
8/5/2003 19.08 78.54
7/6/2012 26.86 70.76
12/27/2012 27.91 69.71
5/6/2013 27.52 70.10
5/10/2013 23.01 74.61
6/11/2013 26.94 70.68
10/14/2013 23.95 73.67
10/18/2013 25.31 72.31
11/13/2013 24.25 73.374/24/2014 21.95 75.675/29/2015 23.02 74.6011/24/2015 25.28 72.346/14/2016 22.53 75.09
8/15/2017 26.62 71.00
7/29/2019 20.20 77.42
3/10/2021 17.95 79.67
3/22/1996 17.53 79.33
3/8/2000 23.84 73.02
8/27/2001 25.83 71.03
2/22/2002
8/6/2002
2/12/2003 26.37 70.49
8/5/2003 17.97 78.89
7/6/2012 26.18 70.68
8/15/2017
7/29/2019 19.51 77.35
3/10/2021
3/22/1996 17.73 79.45
3/8/2000 24.00 73.18
8/27/2001 26.09 71.09
2/22/2002 27.66 69.52
8/6/2002
2/12/2003 26.51 70.67
8/5/2003 18.01 79.17
7/6/2012 26.40 70.78
8/15/2017
7/29/2019 19.80 77.38
3/10/2021
3/22/1996 17.22 79.99
3/8/2000 23.99 73.22
8/27/2001 26.28 70.93
2/22/2002 27.85 69.36
8/6/2002
2/12/2003 26.41 70.80
8/5/2003 17.69 79.52
7/6/2012 26.51 70.70
8/15/2017
7/29/2019 20.01 77.20
3/10/2021 16.76 80.45
Dry
Dry
Not Measured
Not Measured
MW-4 10/2/1995 2 13-28 28 97.21
Not Measured
MW-3 4/21/1995 2 14-29 29 97.18
MW-2 4/21/1995 2 13-28 28 96.86
Not Measured
MW-1 4/21/1995 2 13-28 28 97.62
Not Measured
Dry
Dry
Not Measured
Not Measured
TABLE 4
Monitoring Well Construction Information
and Historical Groundwater Elevations
Lewis Service Station
Fallston, North Carolina
Terracon Project No. 71179012A
NCDEQ Incident No. 3701
3/22/1996 17.39 79.17
3/8/2000 23.30 73.26
8/27/2001 25.28 71.28
2/22/2002 26.76 69.80
8/6/2002 27.67 68.89
2/12/2003 25.53 71.03
8/5/2003 17.74 78.82
7/6/2012 25.63 70.93
8/15/2017
7/29/2019 19.32 77.24
3/10/2021 17.08 79.48
3/22/1996 19.72 77.91
3/8/2000 24.88 72.75
8/27/2001 26.42 71.21
2/22/2002 28.01 69.62
8/6/20022/12/2003 27.21 70.428/5/2003 20.13 77.507/6/2012 26.95 70.68
8/15/2017
7/29/2019 20.68 76.95
3/10/2021 20.37 77.26
3/22/1996 21.42 78.11
3/8/2000 26.95 72.58
8/27/2001 28.5 71.03
2/22/2002 28.99 70.54
8/6/2002
2/12/2003 28.9 70.63
8/5/2003 22.00 77.537/6/2012 28.83 70.708/15/20177/29/20193/10/2021 20.70 78.833/22/1996 18.44 78.97
3/8/2000 24.47 72.94
8/27/2001 26.15 71.26
2/22/2002 28.00 69.41
8/6/2002
2/12/2003 27.05 70.36
8/5/2003 18.89 78.52
7/6/2012 26.65 70.76
8/15/2017
7/29/2019 19.82 77.59
3/10/2021
Notes:
Depth of Well and Top of Casing elevation taken from Monitoring Report, Lewis Service Station dated June 29, 2016 by Shield Engineering, Inc. and Corrective Action Plan, Stamey Store dated
April 1955 by Southeastern Geological Services.
Dry
Not Measured
MW-8 Unknown 2 13-28 28 97.41
Not Measured
10/3/1995 2 15-30 30 97.63
MW-5 Unknown 2 13-28 28 96.56
Not Measured
MW-7 10/3/1995 2 15-30 30 99.53
DryMW-6
Not Measured
Not Measured
Dry
Not Measured
TABLE 4
Monitoring Well Construction Information
and Historical Groundwater Elevations
Lewis Service Station
Fallston, North Carolina
Terracon Project No. 71179012A
NCDEQ Incident No. 3701
3/22/1996 19.16 78.56
3/8/2000 25.06 72.66
8/27/2001 26.76 70.96
2/22/2002 28.60 69.12
8/6/2002 29.15 68.57
2/12/2003 27.56 70.16
8/5/2003 19.59 78.13
7/6/2012 27.28 70.44
12/27/2012 30.02 67.70
5/6/2013 28.05 69.67
5/10/2013 29.43 68.29
6/11/2013 27.30 70.42
10/14/213 24.34 73.38
10/18/2013 24.63 73.09
11/13/2013 24.63 73.09
4/24/2014 22.05 75.67
5/29/2015 23.43 74.29
11/24/2015 25.65 72.07
6/14/2016 22.92 74.80
8/15/2017 26.97 70.73
7/29/2019 20.50 77.22
3/10/2021 18.23 79.49
2/22/2002 28.22 69.16
8/6/2002 28.82 68.56
2/12/2003 27.15 70.23
8/5/2003 19.18 78.20
7/6/2012 26.84 70.54
12/27/2012 29.64 67.74
5/6/2013 27.56 69.82
5/10/2013 30.85 66.53
6/11/2013 26.68 70.70
10/14/2013 23.95 73.43
10/18/2013 24.91 72.47
11/13/2013 24.25 73.13
4/24/2014 22.47 74.91
5/29/2015 23.05 74.33
11/24/2015 25.27 72.11
6/14/2016 22.53 74.85
8/15/2017 26.60 70.80
7/29/2019 20.20 77.18
3/10/2021 18.11 79.27
7/6/2012 16.80 Not Measured
8/15/2017
7/29/2019
7/6/2012 17.23 Not Measured
8/15/2017
7/29/2019
SSMW-2 10/23/1994 7/29/2019 2 18-28 28 101.1 22.70 78.42
Notes:
Depth of Well and Top of Casing elevation taken from Monitoring Report, Lewis Service Station dated June 29, 2016 by Shield Engineering, Inc. and Corrective Action Plan, Stamey Store dated
April 1955 by Southeastern Geological Services.
SVE-1 Unknown 4 Unknown 18 Not Measured Not Measured
Not MeasuredNot Measured18Unknown4UnknownSVE-2
Not Measured
Not Measured
VMW-1 10/5/1995 2 42-45 45 97.72
RW-1 6 15-40 40 97.3810/28/2001

APPENDIX A
REMRX REMEDIATION TREATABILITY
STUDY

2901 East Gate City Blvd, Suite 2200 │ Greensboro, NC 27401 │ 336-217-5171
www.remrxremediation.com 1

Will Frazier, PG
Terracon
2701 Westport Road
Charlotte, NC 28208
[phone]
[e-mail]

September 7, 2021

RE: Lewis Service Station Treatability Study
4733 Fallston Road
Fallston, NC

Dear Mr. Frazier:
The RemRx Team is submitting this letter to document to results of the Lewis Service Station (Site)
treatability study. A summary of the treatability study results is provided below.
Objective
The objective of the treatability study was to determine the effectiveness of hydrogen peroxide for
treatment of site groundwater constituents, primarily 1,2-dibromoethane (EDB). Limited information is
currently available in the literature regarding EDB with respect to degradation by chemical oxidation. The
RemRx Team did find limited data indicating EDB was amendable to chemical oxidation by hydrogen
peroxide. In order to determine if hydrogen peroxide was a good candidate for oxidation of site constituents
and EDB, the RemRx Team conducted a treatability study utilizing site groundwater and hydrogen peroxide
under different dosing and pH conditions.
Methodology
In order to ensure that measurable concentrations of EDB were contained in the samples, EDB was spiked
into the batch reactors containing site groundwater before experiments were performed to yield a higher
starting concentration. To test the ability of hydrogen peroxide to degrade EDB, varying doses of hydrogen
peroxide and iron activator were added to batch reactors containing site water. The results of the initial
testing using various hydrogen peroxide dosings are summarized in Table 1. As shown in Table 1, hydrogen
peroxide effectively degrades EDB as well as other contaminants found at the site (e.g., BTEX, acetone,
MTBE, naphthalene) at relatively modest to higher doses.

Lewis Service Station
Treatability Study

2901 East Gate City Blvd, Suite 2200 │ Greensboro, NC 27401 │ 336-217-5171
www.remrxremediation.com 2

Table 1. Contaminant concentrations (μg/L) after reaction with iron activated hydrogen peroxide at 7
days of reaction time (1x = 10 millimole (mM), 5x = 50 mM, 10x = 100 mM).
CONTAMINANT Untreated
control HP1x HP5x HP10x
Acetone 560 1100 200 81
Benzene 340 0 0 0
2-Butanone (MEK) 0 9.1 0 0
n-Butylbenzene 17 0 0 0
EDB 110 21 0 0
Ethylbenzene 200 0 0 0
Isopropylbenzene 20 0 0 0
MTBE 110 0 0 0
Naphthalene 150 0 0 0
n-Propylbenzene 40 0 0 0
Toluene 1600 0 0 0
1,2,4-Trimethylbenzene 730 0 0 0
1,3,5-Trimethylbenzene 140 0 0 0
m+p Xylene 1100 0 0 0
o-Xylene 900 0 0 0

After confirming that hydrogen peroxide was capable of degrading EDB, additional tests were conducted
using an anhydrous form of hydrogen peroxide called sodium percarbonate. Sodium percarbonate is a solid
adduct of sodium carbonate and hydrogen peroxide, which has advantages in field applications over typical
hydrogen peroxide injections. To understand the efficacy of percarbonate against EDB, equivalent doses
of percarbonate oxidant were added to site water with iron activation. As carbonate is basic, the pH was
adjusted in the batch reactors using an acid. The batch reactors are used to test the reactions in a closed
system. The pH may not require adjusting in a field deployment (open system) as the acidity in the water
may buffer the carbonate. The pH changes over the course of the reaction are shown in Table 2. If pH
adjustment is required based on field pH readings, there are several approved acids on the NCDEQ UIC
injectant approval list that can be added post deployment.

Table 2. Initial and final pH readings for relevant reactions (note PC indicates percarbonate and HP
indicates hydrogen peroxide).
Sample Initial pH Final pH
PC 1x 8.0 8.0
PC 1x high acid dose 4.0 2.5
PC 1x medium acid dose 6.0 5.0 PC 1x low acid dose 6.0 6.8
HP 1x 5.0 3.5
Untreated control 5.5 5.5

A summary of the analytical results is depicted on Figure 1. As shown on Figure 1, percarbonate solutions
that were more acidic resulted in improved degradation kinetics.
Lewis Service Station
Treatability Study

2901 East Gate City Blvd, Suite 2200 │ Greensboro, NC 27401 │ 336-217-5171
www.remrxremediation.com 3

Figure 1. Contaminant concentrations after treatment with percarbonate (PC1x), hydrogen peroxide
(HP1x), and percarbonate with varying doses of acid (high, medium, low).

Treatability Study Results
The results of the treatability study are summarized below.
• The treatability study results indicate that iron activated hydrogen peroxide can effectively degrade
contaminants found at the site.

• The treatability study results also indicate the solid form of hydrogen peroxide, sodium
percarbonate, can also effectively degrade contaminants.

• The reaction kinetics of sodium percarbonate appear to be more efficient at lower pH. Because
carbonate is released into the system, an acid may be required to adjust groundwater pH if the
acidity of site groundwater cannot buffer the carbonate. If pH adjustment is required based on
field pH readings, there are several approved acids on the NCDEQ UIC injectant approval list that
can be added post deployment.

0
200
400
600
800
1000
1200
Untreated
control
PC1x HP1x PC high acid PC med acid PC low acidconcentration (ug/L)benzene
MEK
EDB
ethylbenzene
MTBE
napthalene
toluene
1,2,4-TMB
1,3,5-TMB
m+p xylene
o-xylene
Lewis Service Station
Treatability Study

2901 East Gate City Blvd, Suite 2200 │ Greensboro, NC 27401 │ 336-217-5171
www.remrxremediation.com 4

The RemRx team appreciates the opportunity to assist in this treatability study. If you have any questions,
please feel free to contact us.
Sincerely,

Julia Darcy, PhD Jeff Albano, PG
Research Scientist, Laboratory Lead Technical Services Manager
[e-mail] (336)-217-5168
[e-mail]

NOTICE OF CONFIDENTIAL COMMUNICATION This communication and any subsequent electronic
communication relating to this matter, including any attachments, constitute an “electronic communication”
within the meaning of the Electronic Communications Privacy Act, 18 U.S.C.A. §2510 or any similar law of
any other jurisdiction. In addition, this and any subsequent electronic communication, and any attachments,
may be subject to the attorney-client privilege or be considered attorney work product.

This communication, and any subsequent electronic communication relating to this matter, including any
attachments, is CONFIDENTIAL and is intended solely for the addressee(s). If you are not an intended
recipient, any use, review, dissemination, or copying of any such communication by you is strictly
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not read, copy, use or disclose it to others; also please notify the sender by replying to the communication,
and then delete it and all accompanying files from your system. Please verify that you will delete the
communication in your reply.

APPENDIX B
FIELD NOTES

APPENDIX C
AQTESOLV
RESULTS
0.4.8.12.16.20.
0.01
0.1
1.
Time (min)Displacement(ft)WELL TEST ANALYSIS
Data Set:N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\MW-1 Slug In.aqt
Date:08/31/21 Time:14:24:50
PROJECT INFORMATION
Company:Terracon Consultants
Client:NCDEQ
Project:71179012A
Location:Fallston, NC
Test Well:MW-1
Test Date:7/12/21
AQUIFER DATA
Saturated Thickness:30.08 ft Anisotropy Ratio (Kz/Kr):1.
WELL DATA (MW-1)
Initial Displacement:0.829 ft Static Water Column Height:30.08 ft
Total Well Penetration Depth:28.ft Screen Length:15.ft
Casing Radius:0.083 ft Well Radius:0.333 ft
SOLUTION
Aquifer Model:Unconfined Solution Method:Bouwer-Rice
K =4.837E-5 ft/min y0 =0.2812 ft
AQTESOLV for Windows
Data Set: N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\MW-1 Slug In.aqt
Date: 08/31/21
Time: 14:26:43
PROJECT INFORMATION
Company: Terracon Consultants
Client: NCDEQ
Project: 71179012A
Location: Fallston, NC
Test Date: 7/12/21
Test Well: MW-1
AQUIFER DATA
Saturated Thickness: 30.08 ft
Anisotropy Ratio (Kz/Kr): 1.
SLUG TEST WELL DATA
Test Well:MW-1
X Location: 0. ft
Y Location: 0. ft
Initial Displacement: 0.829 ft
Static Water Column Height: 30.08 ft
Casing Radius: 0.083 ft
Well Radius: 0.333 ft
Well Skin Radius: 0.333 ft
Screen Length: 15. ft
Total Well Penetration Depth: 28. ft
No. of Observations: 115
Observation Data
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.-0.001 0.708 -0.008
0.004183 -0.002 0.75 -0.006
0.008867 0.0.794 -0.009
0.01258 -0.003 0.841 0.269
0.01668 -0.005 0.891 0.829
0.02085 -0.004 0.944 0.448
0.02502 -0.002 1.0.412
0.02918 -0.003 1.06 0.361
0.03335 -0.004 1.12 0.205
0.03752 -0.003 1.19 0.304
0.04168 -0.006 1.26 0.289
0.04585 -0.007 1.33 0.277
0.05002 -0.001 1.41 0.264
0.05418 -0.006 1.5 0.15
0.05835 -0.007 1.58 0.203
0.06252 -0.005 1.68 0.055
0.06668 -0.004 1.78 0.371
08/31/21 1 14:26:44
AQTESOLV for Windows
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.07085 -0.004 1.886 0.363
0.07502 -0.005 1.99 0.247
0.07918 -0.005 2.11 0.259
0.08335 -0.005 2.24 0.248
0.08752 -0.003 2.37 0.242
0.09168 -0.005 2.51 0.235
0.09585 -0.006 2.66 0.228
0.1 -0.003 2.82 0.217
0.106 -0.007 2.98 0.723
0.112 -0.007 3.16 0.206
0.119 -0.007 3.35 0.199
0.126 -0.009 3.554 0.193
0.133 -0.006 3.76 0.269
0.141 -0.007 3.98 0.189
0.15 -0.009 4.222 0.186
0.158 -0.008 4.473 0.179
0.168 -0.003 4.73 0.173
0.178 -0.008 5.01 0.167
0.188 -0.008 5.31 0.163
0.199 -0.009 5.62 0.154
0.211 -0.007 5.96 0.147
0.224 -0.009 6.31 0.138
0.237 -0.009 6.68 0.143
0.251 -0.009 7.08 0.137
0.266 -0.005 7.5 0.133
0.282 -0.008 7.94 0.13
0.298 -0.01 8.41 0.126
0.316 -0.009 8.91 0.116
0.335 -0.007 9.44 0.118
0.355 -0.009 10.0.117
0.376 -0.009 10.6 0.114
0.398 -0.005 11.2 0.11
0.422 -0.008 11.9 0.103
0.447 -0.007 12.6 0.102
0.473 -0.004 13.3 0.103
0.501 -0.004 14.1 0.095
0.531 -0.007 15.0.097
0.562 -0.005 15.8 0.098
0.596 -0.005 16.8 0.089
0.631 -0.005 17.8 0.093
0.668 -0.007
SOLUTION
Slug Test
Aquifer Model: Unconfined
Solution Method: Bouwer-Rice
ln(Re/rw): 3.01
VISUAL ESTIMATION RESULTS
Estimated Parameters
08/31/21 2 14:26:44
AQTESOLV for Windows
Parameter Estimate
K 4.837E-5 ft/min
y0 0.2812 ft
K = 2.457E-5 cm/sec
T = K*b = 0.001455 ft²/min (0.02253 sq. cm/sec)
08/31/21 3 14:26:44
0.4.8.12.16.20.
0.001
0.01
0.1
1.
Time (min)NormalizedHead(ft/ft)WELL TEST ANALYSIS
Data Set:N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\MW-1 Slug IOut.aqt
Date:08/31/21 Time:14:30:17
PROJECT INFORMATION
Company:Terracon Consultants
Client:NCDEQ
Project:71179012A
Location:Fallston, NC
Test Well:MW-1
Test Date:7/12/21
AQUIFER DATA
Saturated Thickness:30.48 ft Anisotropy Ratio (Kz/Kr):1.
WELL DATA (New Well)
Initial Displacement:-0.927 ft Static Water Column Height:30.08 ft
Total Well Penetration Depth:28.ft Screen Length:15.ft
Casing Radius:0.083 ft Well Radius:0.333 ft
SOLUTION
Aquifer Model:Unconfined Solution Method:Bouwer-Rice
K =0.0001085 ft/min y0 =-0.3355 ft
AQTESOLV for Windows
Data Set: N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\MW-1 Slug IOut.aqt
Date: 08/31/21
Time: 14:29:59
PROJECT INFORMATION
Company: Terracon Consultants
Client: NCDEQ
Project: 71179012A
Location: Fallston, NC
Test Date: 7/12/21
Test Well: MW-1
AQUIFER DATA
Saturated Thickness: 30.48 ft
Anisotropy Ratio (Kz/Kr): 1.
SLUG TEST WELL DATA
Test Well:New Well
X Location: 0. ft
Y Location: 0. ft
Initial Displacement: -0.927 ft
Static Water Column Height: 30.08 ft
Casing Radius: 0.083 ft
Well Radius: 0.333 ft
Well Skin Radius: 0.333 ft
Screen Length: 15. ft
Total Well Penetration Depth: 28. ft
No. of Observations: 113
Observation Data
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.0.006 0.668 -0.715
0.004183 0.0.708 -0.698
0.00835 0.009 0.75 -0.681
0.0133 0.003 0.794 -0.663
0.01702 0.002 0.841 -0.645
0.02085 -0.003 0.8993 -0.622
0.02502 -0.003 0.944 -0.607
0.02918 -0.003 1.-0.59
0.03335 -0.004 1.067 -0.572
0.03752 0.1.12 -0.553
0.04168 -0.003 1.19 -0.53
0.04585 -0.003 1.26 -0.51
0.05002 0.1.33 -0.493
0.05418 -0.005 1.41 -0.472
0.05835 -0.001 1.5 -0.45
0.06252 -0.002 1.58 -0.431
0.06668 0.002 1.68 -0.409
08/31/21 1 14:29:59
AQTESOLV for Windows
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.07085 -0.004 1.78 -0.388
0.07502 -0.001 1.88 -0.368
0.07918 -0.001 1.99 -0.352
0.08335 0.2.11 -0.332
0.08752 -0.005 2.24 -0.315
0.09168 -0.002 2.37 -0.293
0.09585 0.001 2.51 -0.279
0.1 -0.003 2.66 -0.257
0.1061 -0.006 2.82 -0.237
0.112 -0.006 2.987 -0.222
0.119 -0.003 3.16 -0.202
0.126 -0.002 3.35 -0.19
0.133 -0.006 3.55 -0.174
0.1482 -0.007 3.76 -0.162
0.152 0.3.988 -0.146
0.158 -0.005 4.22 -0.136
0.168 -0.003 4.47 -0.125
0.178 -0.007 4.74 -0.116
0.188 -0.005 5.01 -0.109
0.199 -0.005 5.31 -0.1
0.211 -0.006 5.62 -0.091
0.2318 -0.001 5.96 -0.08
0.237 -0.003 6.31 -0.078
0.251 -0.005 6.68 -0.078
0.266 -0.005 7.08 -0.069
0.282 -0.368 7.5 -0.068
0.298 0.011 7.94 -0.059
0.316 -0.927 8.412 -0.063
0.335 -0.907 8.913 -0.062
0.355 -0.888 9.44 -0.055
0.376 -0.873 10.-0.055
0.3987 -0.856 10.6 -0.056
0.422 -0.844 11.2 -0.047
0.447 -0.828 11.9 -0.041
0.4821 -0.804 12.6 -0.042
0.501 -0.796 13.3 -0.042
0.531 -0.78 14.1 -0.04
0.5655 -0.761 15.-0.029
0.596 -0.746 15.8 -0.034
0.631 -0.729
SOLUTION
Slug Test
Aquifer Model: Unconfined
Solution Method: Bouwer-Rice
ln(Re/rw): 2.994
VISUAL ESTIMATION RESULTS
Estimated Parameters
Parameter Estimate
08/31/21 2 14:30:00
AQTESOLV for Windows
K 0.0001085 ft/min
y0 -0.3355 ft
K = 5.51E-5 cm/sec
T = K*b = 0.003306 ft²/min (0.05119 sq. cm/sec)
08/31/21 3 14:30:00
0.6.12.18.24.30.
0.001
0.01
0.1
1.
Time (min)Displacement(ft)WELL TEST ANALYSIS
Data Set:N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\RW-1 Slug In.aqt
Date:08/31/21 Time:14:30:36
PROJECT INFORMATION
Company:Terracon Consultants
Client:NCDEQ
Project:71179012A
Location:Fallston, NC
Test Well:RW-1
Test Date:7/12/21
AQUIFER DATA
Saturated Thickness:30.22 ft Anisotropy Ratio (Kz/Kr):1.
WELL DATA (RW-1)
Initial Displacement:0.133 ft Static Water Column Height:30.22 ft
Total Well Penetration Depth:40.ft Screen Length:25.ft
Casing Radius:0.25 ft Well Radius:0.5 ft
SOLUTION
Aquifer Model:Unconfined Solution Method:Bouwer-Rice
K =0.0006533 ft/min y0 =0.08586 ft
AQTESOLV for Windows
Data Set: N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\RW-1 Slug In.aqt
Date: 08/31/21
Time: 14:30:48
PROJECT INFORMATION
Company: Terracon Consultants
Client: NCDEQ
Project: 71179012A
Location: Fallston, NC
Test Date: 7/12/21
Test Well: RW-1
AQUIFER DATA
Saturated Thickness: 30.22 ft
Anisotropy Ratio (Kz/Kr): 1.
SLUG TEST WELL DATA
Test Well:RW-1
X Location: 0. ft
Y Location: 0. ft
Initial Displacement: 0.133 ft
Static Water Column Height: 30.22 ft
Casing Radius: 0.25 ft
Well Radius: 0.5 ft
Well Skin Radius: 0.5 ft
Screen Length: 25. ft
Total Well Penetration Depth: 40. ft
No. of Observations: 120
Observation Data
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.0.0.794 0.071
0.004183 0.005 0.841 0.074
0.00835 -0.006 0.891 0.071
0.01367 -0.005 0.944 0.072
0.01737 -0.013 1.0.071
0.02107 -0.009 1.06 0.072
0.02502 -0.013 1.12 0.068
0.02918 -0.016 1.19 0.066
0.03335 -0.014 1.26 0.068
0.03752 -0.014 1.332 0.065
0.04168 -0.016 1.416 0.065
0.04585 -0.018 1.5 0.065
0.05002 -0.012 1.583 0.064
0.05418 -0.015 1.68 0.066
0.05835 -0.01 1.78 0.066
0.06252 -0.011 1.88 0.065
0.06668 -0.011 1.99 0.057
08/31/21 1 14:30:48
AQTESOLV for Windows
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.0709 -0.012 2.11 0.06
0.07502 -0.012 2.24 0.061
0.07918 -0.013 2.37 0.057
0.08335 -0.01 2.51 0.059
0.08752 -0.014 2.669 0.056
0.09168 -0.015 2.82 0.056
0.09585 -0.012 2.98 0.053
0.1 -0.012 3.169 0.053
0.106 -0.018 3.35 0.056
0.112 -0.017 3.55 0.055
0.119 -0.016 3.76 0.051
0.126 -0.018 3.98 0.048
0.133 -0.018 4.22 0.045
0.141 -0.018 4.47 0.048
0.15 -0.015 4.73 0.049
0.158 -0.019 5.01 0.044
0.168 -0.02 5.31 0.038
0.178 -0.021 5.62 0.039
0.188 -0.017 5.96 0.034
0.199 -0.014 6.31 0.033
0.211 -0.016 6.68 0.034
0.224 -0.02 7.08 0.033
0.237 -0.017 7.5 0.033
0.251 -0.019 7.94 0.031
0.266 -0.019 8.41 0.031
0.282 -0.019 8.91 0.03
0.298 -0.019 9.44 0.023
0.316 -0.018 10.0.026
0.335 -0.019 10.6 0.018
0.355 -0.011 11.2 0.018
0.376 0.133 11.9 0.016
0.398 0.116 12.6 0.009
0.422 0.094 13.3 0.011
0.447 0.08 14.1 0.008
0.473 0.086 15.0.003
0.501 0.082 15.8 0.006
0.531 0.082 16.8 0.005
0.562 0.079 17.8 0.002
0.596 0.077 18.8 -0.009
0.631 0.077 19.8 -0.007
0.668 0.076 20.8 -0.007
0.708 0.072 21.8 -0.011
0.75 0.071 22.8 -0.013
SOLUTION
Slug Test
Aquifer Model: Unconfined
Solution Method: Bouwer-Rice
ln(Re/rw): 3.291
VISUAL ESTIMATION RESULTS
08/31/21 2 14:30:48
AQTESOLV for Windows
Estimated Parameters
Parameter Estimate
K 0.0006533 ft/min
y0 0.08586 ft
K = 0.0003319 cm/sec
T = K*b = 0.01974 ft²/min (0.3057 sq. cm/sec)
08/31/21 3 14:30:48
0.6.12.18.24.30.
0.001
0.01
0.1
1.
Time (min)NormalizedHead(ft/ft)WELL TEST ANALYSIS
Data Set:N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\RW-1 Slug Out.aqt
Date:08/31/21 Time:14:31:14
PROJECT INFORMATION
Company:Terracon Consultants
Client:NCDEQ
Project:71179012A
Location:Fallston, NC
Test Well:RW-1
Test Date:7/12/21
AQUIFER DATA
Saturated Thickness:30.22 ft Anisotropy Ratio (Kz/Kr):1.
WELL DATA (RW-1)
Initial Displacement:-0.164 ft Static Water Column Height:30.22 ft
Total Well Penetration Depth:40.ft Screen Length:25.ft
Casing Radius:0.25 ft Well Radius:0.5 ft
SOLUTION
Aquifer Model:Unconfined Solution Method:Bouwer-Rice
K =0.0001461 ft/min y0 =-0.1011 ft
AQTESOLV for Windows
Data Set: N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\RW-1 Slug Out.aqt
Date: 08/31/21
Time: 14:31:27
PROJECT INFORMATION
Company: Terracon Consultants
Client: NCDEQ
Project: 71179012A
Location: Fallston, NC
Test Date: 7/12/21
Test Well: RW-1
AQUIFER DATA
Saturated Thickness: 30.22 ft
Anisotropy Ratio (Kz/Kr): 1.
SLUG TEST WELL DATA
Test Well:RW-1
X Location: 0. ft
Y Location: 0. ft
Initial Displacement: -0.164 ft
Static Water Column Height: 30.22 ft
Casing Radius: 0.25 ft
Well Radius: 0.5 ft
Well Skin Radius: 0.5 ft
Screen Length: 25. ft
Total Well Penetration Depth: 40. ft
No. of Observations: 118
Observation Data
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.0.0.75 -0.097
0.004183 -0.003 0.794 -0.098
0.00835 -0.002 0.841 -0.104
0.0152 -0.001 0.891 -0.097
0.01887 -0.004 0.944 -0.077
0.02255 -0.009 1.-0.096
0.0262 -0.01 1.06 -0.095
0.02987 -0.011 1.12 -0.093
0.03352 -0.009 1.19 -0.093
0.03752 -0.01 1.26 -0.094
0.04168 -0.011 1.33 -0.094
0.04585 -0.01 1.41 -0.093
0.05002 -0.011 1.5 -0.094
0.05418 -0.012 1.58 -0.089
0.05835 -0.007 1.689 -0.091
0.06252 -0.008 1.78 -0.09
0.06668 -0.011 1.88 -0.088
08/31/21 1 14:31:27
AQTESOLV for Windows
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.07085 -0.01 1.99 -0.088
0.07502 -0.012 2.11 -0.088
0.07918 -0.013 2.24 -0.087
0.08335 -0.009 2.37 -0.089
0.08752 -0.007 2.51 -0.089
0.1016 -0.018 2.66 -0.088
0.1056 -0.01 2.82 -0.087
0.1093 -0.014 2.98 -0.085
0.1129 -0.008 3.16 -0.082
0.1166 -0.011 3.359 -0.082
0.1203 -0.009 3.55 -0.08
0.126 -0.015 3.76 -0.079
0.133 -0.016 3.98 -0.077
0.141 -0.013 4.22 -0.076
0.15 -0.017 4.47 -0.08
0.158 0.036 4.73 -0.078
0.168 -0.055 5.01 -0.077
0.1852 -0.08 5.31 -0.077
0.1889 -0.164 5.62 -0.077
0.199 -0.121 5.96 -0.076
0.211 -0.125 6.31 -0.077
0.224 -0.13 6.68 -0.073
0.237 -0.127 7.08 -0.072
0.251 -0.124 7.5 -0.076
0.2687 -0.126 7.95 -0.073
0.282 -0.122 8.41 -0.069
0.298 -0.123 8.91 -0.072
0.316 -0.12 9.44 -0.065
0.335 -0.117 10.-0.076
0.355 -0.118 10.6 -0.068
0.376 -0.112 11.21 -0.061
0.398 -0.115 11.9 -0.063
0.422 -0.113 12.6 -0.063
0.447 -0.109 13.3 -0.063
0.473 -0.113 14.1 -0.064
0.501 -0.104 15.-0.061
0.531 -0.104 15.8 -0.066
0.562 -0.104 16.8 -0.06
0.603 -0.106 17.8 -0.059
0.631 -0.102 18.8 -0.052
0.668 -0.102 19.81 -0.062
0.708 -0.099 20.8 -0.063
SOLUTION
Slug Test
Aquifer Model: Unconfined
Solution Method: Bouwer-Rice
ln(Re/rw): 3.291
VISUAL ESTIMATION RESULTS
Estimated Parameters
08/31/21 2 14:31:27
AQTESOLV for Windows
Parameter Estimate
K 0.0001461 ft/min
y0 -0.1011 ft
K = 7.424E-5 cm/sec
T = K*b = 0.004416 ft²/min (0.06838 sq. cm/sec)
08/31/21 3 14:31:27
0.6.12.18.24.30.
0.001
0.01
0.1
1.
10.
Time (min)Displacement(ft)WELL TEST ANALYSIS
Data Set:N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\VMW-1 Slug In.aqt
Date:08/31/21 Time:14:31:42
PROJECT INFORMATION
Company:Terracon Consultants
Client:NCDEQ
Project:71179012A
Location:Fallston, NC
Test Well:VMW-1
Test Date:7/12/21
AQUIFER DATA
Saturated Thickness:30.51 ft Anisotropy Ratio (Kz/Kr):1.
WELL DATA (VMW-1)
Initial Displacement:1.714 ft Static Water Column Height:30.51 ft
Total Well Penetration Depth:45.ft Screen Length:3.ft
Casing Radius:0.083 ft Well Radius:0.333 ft
SOLUTION
Aquifer Model:Unconfined Solution Method:Bouwer-Rice
K =0.0002633 ft/min y0 =0.8964 ft
AQTESOLV for Windows
Data Set: N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\VMW-1 Slug In.aqt
Date: 08/31/21
Time: 14:31:53
PROJECT INFORMATION
Company: Terracon Consultants
Client: NCDEQ
Project: 71179012A
Location: Fallston, NC
Test Date: 7/12/21
Test Well: VMW-1
AQUIFER DATA
Saturated Thickness: 30.51 ft
Anisotropy Ratio (Kz/Kr): 1.
SLUG TEST WELL DATA
Test Well:VMW-1
X Location: 0. ft
Y Location: 0. ft
Initial Displacement: 1.714 ft
Static Water Column Height: 30.51 ft
Casing Radius: 0.083 ft
Well Radius: 0.333 ft
Well Skin Radius: 0.333 ft
Screen Length: 3. ft
Total Well Penetration Depth: 45. ft
No. of Observations: 125
Observation Data
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.0.0.944 1.003
0.004183 0.001 1.005 0.988
0.00835 0.019 1.06 0.978
0.01547 0.005 1.12 0.966
0.01913 0.009 1.19 0.946
0.02283 -0.002 1.26 0.931
0.02648 -0.002 1.339 0.914
0.03013 -0.004 1.41 0.9
0.0338 0.002 1.506 0.882
0.03745 -0.001 1.59 0.866
0.04168 -0.001 1.68 0.847
0.04585 -0.005 1.78 0.832
0.05002 -0.002 1.88 0.816
0.05418 -0.005 1.99 0.795
0.05835 -0.002 2.11 0.774
0.06252 -0.002 2.24 0.753
0.06668 -0.004 2.37 0.727
08/31/21 1 14:31:53
AQTESOLV for Windows
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.07085 -0.004 2.51 0.709
0.07502 0.002 2.66 0.688
0.08875 0.016 2.82 0.661
0.09242 0.026 2.98 0.643
0.09607 0.025 3.16 0.61
0.09973 0.019 3.35 0.595
0.1034 0.018 3.55 0.571
0.1071 0.02 3.761 0.542
0.1108 0.021 3.98 0.517
0.1145 0.022 4.22 0.5
0.119 0.02 4.47 0.47
0.126 0.019 4.73 0.444
0.133 0.019 5.013 0.426
0.141 0.022 5.31 0.397
0.15 0.021 5.62 0.38
0.158 0.04 5.96 0.354
0.1718 0.004 6.31 0.337
0.178 -0.045 6.681 0.314
0.188 -0.048 7.08 0.291
0.199 -0.047 7.5 0.277
0.211 -0.042 7.94 0.252
0.224 -0.043 8.41 0.239
0.237 -0.038 8.91 0.219
0.2536 1.562 9.44 0.206
0.266 1.714 10.0.192
0.282 1.104 10.61 0.174
0.298 1.095 11.2 0.162
0.316 1.034 11.9 0.151
0.3372 1.692 12.61 0.136
0.355 1.491 13.3 0.132
0.376 1.124 14.1 0.121
0.398 1.139 15.0.11
0.422 1.131 15.8 0.11
0.447 1.129 16.8 0.104
0.473 1.124 17.8 0.102
0.5041 1.11 18.8 0.099
0.531 1.107 19.8 0.09
0.562 1.098 20.8 0.088
0.596 1.085 21.8 0.093
0.631 1.08 22.8 0.089
0.6714 1.069 23.8 0.085
0.708 1.063 24.8 0.075
0.7548 1.047 25.8 0.086
0.794 1.044 26.8 0.075
0.841 1.026 27.8 0.079
0.891 1.009
SOLUTION
Slug Test
Aquifer Model: Unconfined
Solution Method: Bouwer-Rice
ln(Re/rw): 2.777
08/31/21 2 14:31:53
AQTESOLV for Windows
VISUAL ESTIMATION RESULTS
Estimated Parameters
Parameter Estimate
K 0.0002633 ft/min
y0 0.8964 ft
K = 0.0001337 cm/sec
T = K*b = 0.008032 ft²/min (0.1244 sq. cm/sec)
08/31/21 3 14:31:53
0.4.8.12.16.20.
0.001
0.01
0.1
1.
Time (min)NormalizedHead(ft/ft)WELL TEST ANALYSIS
Data Set:N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\VMW-1 Slug Out.aqt
Date:08/31/21 Time:14:32:08
PROJECT INFORMATION
Company:Terracon Consultants
Client:NCDEQ
Project:71179012A
Location:Fallston, NC
Test Well:VMW-1
Test Date:7/12/21
AQUIFER DATA
Saturated Thickness:30.51 ft Anisotropy Ratio (Kz/Kr):1.
WELL DATA (VMW-1)
Initial Displacement:-2.011 ft Static Water Column Height:30.51 ft
Total Well Penetration Depth:45.ft Screen Length:3.ft
Casing Radius:0.083 ft Well Radius:0.33 ft
SOLUTION
Aquifer Model:Unconfined Solution Method:Bouwer-Rice
K =0.0003567 ft/min y0 =-0.6525 ft
AQTESOLV for Windows
Data Set: N:\Projects\2017\71179012A\Working Files\4 - Field Data\TA-02\VMW-1 Slug Out.aqt
Date: 08/31/21
Time: 14:32:23
PROJECT INFORMATION
Company: Terracon Consultants
Client: NCDEQ
Project: 71179012A
Location: Fallston, NC
Test Date: 7/12/21
Test Well: VMW-1
AQUIFER DATA
Saturated Thickness: 30.51 ft
Anisotropy Ratio (Kz/Kr): 1.
SLUG TEST WELL DATA
Test Well:VMW-1
X Location: 0. ft
Y Location: 0. ft
Initial Displacement: -2.011 ft
Static Water Column Height: 30.51 ft
Casing Radius: 0.083 ft
Well Radius: 0.33 ft
Well Skin Radius: 0.33 ft
Screen Length: 3. ft
Total Well Penetration Depth: 45. ft
No. of Observations: 114
Observation Data
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.0.0.668 -0.945
0.004183 -0.005 0.708 -0.933
0.00835 -0.003 0.75 -0.924
0.01252 0.0.794 -0.914
0.01668 -0.002 0.841 -0.914
0.02085 -0.004 0.8968 -0.893
0.02502 -0.006 0.944 -0.884
0.02918 -0.006 1.-0.875
0.03335 -0.14 1.064 -0.859
0.03752 -0.208 1.12 -0.85
0.04168 -0.835 1.19 -0.834
0.04585 -1.449 1.26 -0.826
0.05002 -1.083 1.33 -0.805
0.05418 -2.011 1.41 -0.789
0.05835 -1.037 1.5 -0.772
0.06252 -1.52 1.58 -0.762
0.06668 -1.139 1.68 -0.749
08/31/21 1 14:32:23
AQTESOLV for Windows
Time (min)Displacement (ft)Time (min)Displacement (ft)
0.07085 -0.086 1.78 -0.726
0.07502 -0.997 1.88 -0.704
0.07918 -1.15 1.99 -0.694
0.08335 -1.131 2.11 -0.673
0.08752 -1.118 2.24 -0.654
0.09168 -1.113 2.37 -0.638
0.09585 -1.101 2.51 -0.612
0.1 -1.102 2.66 -0.593
0.106 -1.109 2.82 -0.575
0.112 -1.102 2.985 -0.551
0.119 -1.102 3.16 -0.527
0.126 -1.092 3.35 -0.509
0.133 -1.089 3.55 -0.488
0.141 -1.1 3.76 -0.46
0.15 -1.088 3.986 -0.443
0.158 -1.085 4.22 -0.418
0.168 -1.078 4.47 -0.394
0.178 -1.074 4.737 -0.368
0.188 -1.073 5.01 -0.345
0.199 -1.068 5.31 -0.329
0.211 -1.064 5.62 -0.312
0.224 -1.06 5.96 -0.288
0.237 -1.058 6.31 -0.264
0.251 -1.051 6.68 -0.25
0.266 -1.046 7.08 -0.229
0.282 -1.04 7.5 -0.205
0.298 -1.038 7.94 -0.194
0.316 -1.034 8.411 -0.171
0.335 -1.028 8.912 -0.156
0.355 -1.024 9.44 -0.141
0.376 -1.016 10.-0.125
0.398 -1.01 10.6 -0.119
0.422 -1.013 11.2 -0.104
0.447 -0.998 11.9 -0.092
0.4788 -0.991 12.6 -0.082
0.501 -0.983 13.3 -0.072
0.531 -0.98 14.1 -0.067
0.5629 -0.975 15.01 -0.059
0.596 -0.962 15.8 -0.047
0.631 -0.957 16.8 -0.043
SOLUTION
Slug Test
Aquifer Model: Unconfined
Solution Method: Bouwer-Rice
ln(Re/rw): 2.786
VISUAL ESTIMATION RESULTS
Estimated Parameters
Parameter Estimate
08/31/21 2 14:32:23
AQTESOLV for Windows
K 0.0003567 ft/min
y0 -0.6525 ft
K = 0.0001812 cm/sec
T = K*b = 0.01088 ft²/min (0.1685 sq. cm/sec)
08/31/21 3 14:32:23

APPENDIX D
RBCA TOOLKIT
MODEL RESULTS
RBCA Tool Kit for Chemical Releases, Version 2.6
#4. RBCA Evaluation Process
1. Project Information
Site Name:
Location:
Completed By:
Date:16-Sep-21 Job ID:71179012A
2. Which Type of RBCA Analysis?
####
####
####
3. Calculation Options
###
###
Individual Constituent Risk Goals Only
Individual and Cumulative Risk Goals 5. Commands and Options
Apply Source Depletion Algorithm
Time to Future Exposure 0 (yr)
Terracon Consultants, Inc.
4733 Fallston Road, Fallston, North Carolina
Lewis Service Station
Baseline Risks (Forward mode)
RBCA Cleanup Levels (Backward mode)
Main Screen
Affects which input data are required
Prepare Input Data Review Output
Data Complete? ( = yes, = no)
Site-Specific
Target Levels
Risk-Based
Screening
Levels
Tier 1 Tier 2/3
RBCA Tool Kit for Chemical Releases
© 2011 GSI Environmental Inc.Version 2.6
User Chemical
Database
?
Print Sheet
New Site
QuitHelp
Save Data As...
?
Set Units Print Report
Load Data...
Exposure Pathways
Air ParametersAir Parameters
GW Parameters
Soil ParametersSoil Parameters
Transport Models
Constituents of Concern
(COC s)
Exposure Flowchart
COC Chem. Parameters
Input Data Summary
User-Spec. COC Data...
Transient Domenico Analysis...
Baseline Risks...
Cleanup Levels...
RBCA Tool Kit for Chemical Releases, Version 2.6
#Site Name: Lewis Service Station
Location: 4733 Fallston Road, Fallston, North Carolina 1. Groundwater Exposure Compl. By: Terracon Consultants, Inc.
Groundwater Ingestion/Job ID: 71179012A Date: 16-Sep-21
Surface Water Impact 3. Air Exposure
Receptor: to Outdoor Air Inhalation
On-site Off-site1 Off-site2 Receptor:
Distance:0 715 0 (ft)On-site Off-site1 Off-site2
Source Media:Distance:0 0 0 (ft)
Affected Groundwater Source Media:Construction worker
Affected Soils Leaching to Groundwater Affected Soils--Volatilization to Ambient Outdoor Air
Option:Affected Groundwater--Volatilization to Ambient Outdoor Air
Apply MCL value as ingestion RBEL (backward mode only)Affected Surface Soils--Particulates to Ambient Outdoor Air
GW Discharge to Surface Water Exposure Volatilization to Indoor Air Inhalation
Swimming Receptor:
Fish Consumption On-site Off-site1 Off-site2
Specified Water Quality Criteria Source Media:Distance:0 0 0 (ft)
Affected Soils--Volatilization to Enclosed Space
Affected Soils Leaching to GW--Volatilization to Enclosed Space 2. Surface Soil Exposure Affected Groundwater--Volatilization to Enclosed Space
Source Media:
Receptor: Direct Ingestion 4. Commands and Options
On-site Dermal Contact
Construction Worker Inhalation (vol+part)
Option: Vegetable Ingestion
Apply UK (CLEA) SGV as soil concentration limit
Combined Exposure
Volatilization and Particulates
Exposure Pathway Identification
Main Screen Print Sheet Help
?
?
?
Exposure Flowchart
Set Units
?
Veg OptionsVeg Options
Bldg OptionsBldg Options
Exposure Factors & Target Risks
Enter CriteriaEnter Criteria
RBCA Tool Kit for Chemical Releases, Version 2.6
Site Name: Lewis Service Station Job ID: 71179012A Commands and Options
Location: 4733 Fallston Road, Fallston, North Carolina Date: 16-Sep-21
Compl. By: Terracon Consultants, Inc.
Selected COCs Representative COC Concentration
Groundwater Source Zone Soil Source Zone Mole Fraction
o n in Source
n o Material
(mg/L)note (mg/kg)note (-)
Benzene 3.2E-1 Concentrations used in the model are
Toluene 2.4E+0 the highest identified within the three
Ethyl benzene 3.3E-1 source area wells (MW-1, VMW-1,
Xylenes (mixed isomers)4.0E+0 and RW-1) during the most recent
Ethylene dibromide 7.4E-2 sampling event (March 2021).
Methyl t-Butyl ether (MTBE)1.3E-1
Apply
Raoult's
Law
Source Media Constituents of Concern (COCs)
COC Select:Sort List:
Top
Bottom
MoveUpAdd/Insert
Delete MoveDown
Main Screen Print Sheet Help
?
??
View Chemical Parameters
Enter Site DataEnter Site Data Enter Site DataEnter Site Data
RBCA Tool Kit for Chemical Releases, Version 2.6
#Site Name: Lewis Service Station Job ID: 71179012A
Location: 4733 Fallston Road, Fallston, North Carolina Date: 16-Sep-21
1. Water-Bearing Unit Compl. By: Terracon Consultants, Inc.
Hydrogeology 3. Groundwater Dispersion
Groundwater Darcy velocity 1.6E+0 (ft/yr)Model:GW Ingestion
Groundwater seepage velocity 4.6E+0 (ft/yr)Off-site 1 Off-site 2 Off-site 1 Off-site 2
or Distance to GW receptors 715 0 0 0 (ft)
Hydraulic conductivity 1.4E+2 (ft/yr)
Hydraulic gradient 0.0113 (-)Longitudinal dispersivity 71.5 0 0 0 (ft)
Effective porosity 0.35 (-)Transverse dispersivity 23.595 0 0 0 (ft)
Sorption Vertical dispersivity 3.575 0 0 0 (ft)
Fraction organic carbon--saturated zone 0.001 (-) 4. Groundwater Discharge to Surface Water
Groundwater pH 9 (-)
2. Groundwater Source Zone Off-site 2
Groundwater plume width at source 45 (ft)Distance to GW/SW disharge point NA (ft)
Plume (mixing zone) thickness at source 30 (ft)
Plume width at GW/SW discharge (ft)
Saturated thickness 2 (ft)Plume thickness at GW/SW discharge (ft)
Length of source zone 147.637795 (ft)
Surface water flowrate at GW/SW discharge (ft^3/yr)
5. Commands and Options
GW to Indoor Air
Site-Specific Groundwater Parameters
or
or
?
?
?
Main Screen Use/Set Default
ValuesSet Units
Print Sheet
Help
?
RBCA Tool Kit for Chemical Releases, Version 2.6
##Site Name: Lewis Service Station Job ID: 71179012A
Location: 4733 Fallston Road, Fallston, North Carolina Date: 16-Sep-21
1. Vertical Transport, Surface Soil Column Compl. By: Terracon Consultants, Inc.
Outdoor Air Volatilization Factors 3. Groundwater Dilution Attenuation Factor
Surface soil volatilization model only
Combination surface soil/Johnson & Ettinger models
Thickness of surface soil zone 3.28 (ft)Calculate DAF using Domenico Model
User-specified VF from other model Domenico equation with dispersion only (no biodegradation)
Indoor Air Volatilization Factors Domenico equation first-order decay
Johnson & Ettinger model for soil and groundwater volatilization Modified Domenico equation using
Johnson & Ettinger for soil, Mass Flux model for groundwater electron acceptor superposition
User-specified VF from other model Biodegradation Capacity NC (mg/L)
Soil-to-Groundwater Leaching Factor — or —
ASTM Model User-Specified DAF Values
Apply Soil Attenuation Model (SAM)DAF values from other model or site data
Allow first-order biodecay
User-specified LF from other model 4. Chemical Decay and Source Depletion
Modeling Options
Disable Mass Balance Limit
Apply Dual Equilibrium Desorption Model
2. Lateral Air Dispersion Factor 5. Commands and Options
3-D Gaussian dispersion model Off-site 1 Off-site 2
User-Specified ADF 1.00E+0 1.00E+0 (-)
Transport Modeling Options
C
Enter VF ValuesEnter VF Values
Print SheetMain Screen Help
?
?
ASTM ModelASTM Model
?
Enter Source MassEnter Source Mass
Enter Decay RatesEnter Decay Rates
Enter DAF ValuesEnter DAF Values
Enter Site DataEnter Site Data
Enter Decay Rates
Enter Decay RatesEnter Decay Rates
Enter LF ValuesEnter LF Values
Enter VF ValuesEnter VF Values
?
?
?
?
C
RBCA Tool Kit for Chemical Releases, Version 2.6
Site Name: Lewis Service Station Job ID: 71179012A Commands and Options
Location: 4733 Fallston Road, Fallston, North Carolina Date: 0-Jan-00
Compl. By: Terracon Consultants, Inc.
Saturated Zone Unsaturated Zone
First-Order Decay First-Order Decay
Constituent Half-Life Coefficient Half-Life Coefficient
(day)(1/day)(day)(1/day)
Benzene 7.2E+2 9.6E-4 7.2E+2 9.6E-4
Toluene 2.8E+1 2.5E-2 2.8E+1 2.5E-2
Ethyl benzene 2.3E+2 3.0E-3 2.3E+2 3.0E-3
Xylenes (mixed isomers)3.6E+2 1.9E-3 3.6E+2 1.9E-3
Ethylene dibromide 1.2E+2 5.8E-3 1.2E+2 5.8E-3
Methyl t-Butyl ether (MTBE)3.6E+2 1.9E-3 1.8E+2 3.9E-3
Constituent Decay Rates
Return Print Sheet
HelpPaste Default Values
RBCA Tool Kit for Chemical Releases, Version 2.6
Input Parameter Summary
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.
Site Location: 4733 Fallston Road, Fallston, North Carolina Date Completed: 16-Sep-21
Exposure Parameters Residential User Defined
Child*Adolescent Adult Age Adjusted**Adult Construct.
ATc Averaging time for carcinogens (yr)70 70 70 NA 70 70 -
ATn Averaging time for non-carcinogens (yr)6 12 30 NA 25 1 -
BW Body weight (kg)15 35 70 NA 70 70 -
ED Exposure duration (yr)6 12 30 NA 25 1 -
t Averaging time for vapor flux (yr)30 30 30 NA 30 30 -
EF Exposure frequency (days/yr)350 350 350 NA 250 180 -
EFD Exposure frequency for dermal exposure 350 350 350 NA 250 180 -
IRw Ingestion rate of water (L/day)1 1 2 2.5 1 NA -
IRs Ingestion rate of soil (mg/day)200 200 100 387 50 100 -
SA Skin surface area (dermal) (cm^2)2023 2023 3160 4771 3160 3160 -
M Soil to skin adherence factor 0.5 0.5 0.5 NA 0.5 0.5 -
ETswim Swimming exposure time (hr/event)1 3 3 NA NA NA NA
EVswim Swimming event frequency (events/yr)12 12 12 NA NA NA NA
IRswim Water ingestion while swimming (L/hr)0.5 0.5 0.05 0.3 NA NA NA
SAswim Skin surface area for swimming (cm^2)3500 8100 23000 15680 NA NA NA
IRfish Ingestion rate of fish (kg/yr)0.025 0.025 0.025 0.053 NA NA NA
FIfish Contaminated fish fraction (unitless)1 1 1 NA NA NA NA
IRbg Below-ground vegetable ingestion 0.002 0.002 0.006 2.053 NA NA NA
IRabg Above-ground vegetable ingestion 0.001 0.001 0.002 0.887 NA NA NA
VGbg Above-ground Veg. Ingest. Correction Factor 0.01 0.01 0.01 NA NA NA NA
VGabg Below-ground Veg. Ingest. Correction Factor 0.01 0.01 0.01 NA NA NA NA
* = Child Receptor used for Non-Carcinogens
** = Age-adjusted rate is effective value corresponding to adult exposure factors.
Complete Exposure Pathways and Receptors On-site Off-site 1 Off-site 2
Groundwater:
Groundwater Ingestion None Residential None
Soil Leaching to Groundwater Ingestion None None None
Apply MCL Values No No No
Applicable Surface Water Exposure Routes:
Swimming NA NA None
Fish Consumption NA NA None
Aquatic Life Protection NA NA None
Soil:
Direct Contact: direct combined pathways None NA NA
Apply CLEA- UK SGV levels
Outdoor Air:
Particulates from Surface Soils None None None
Volatilization from Soils None None None
Volatilization from Groundwater None None None
Indoor Air:
Volatilization from Soils None NA NA
Volatilization from Groundwater None None None
Soil Leaching to Groundwater Volatilization None None None
Receptor Distance from Source Media On-site Off-site 1 Off-site 2 (Units)
Groundwater receptor NA 715 NA (ft)
Outdoor air inhalation receptor NA NA NA (ft)
Indoor air inhalation receptor NA NA NA (ft)
Target Health Risk Values Individual Cumulative
TR Target Risk (carcinogens)1.0E-5 1.0E-5
THQ Target Hazard Quotient (non-carcinogenic risk)1.0E+0 1.0E+0
Modeling Options
RBCA tier Tier 2
Outdoor air volatilization model NA
Indoor air volatilization model NA
Soil leaching model NA
Use soil attenuation model (SAM) for leachate? NA
Use dual equilibrium desorption model? NA
Apply Mass Balance Limit for Soil Volatilization? NA
Apply UK (CLEA) SGV as soil concentration limit No
Vegetable calculation options NA
Air dilution factor NA
Groundwater dilution-attenuation factor Domenico model w/ biodeg.
NOTE: NA = Not applicable
Yellow = User-defined default value (different from RBCA Tool Kit default)
Orange = Site-specific value (different from current default value)
No
RBCA SITE ASSESSMENT
Commercial/Industrial
RBCA Tool Kit for Chemical Releases, Version 2.6
Input Parameter Summary
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.
Site Location: 4733 Fallston Road, Fallston, North Carolina Date Completed: 16-Sep-21
Surface Soil Column Parameters Value (Units)
hcap Capillary zone thickness NA (ft)
hv Vadose zone thickness NA (ft)
rs Soil bulk density NA (g/cm^3)
foc Fraction organic carbon NA (-)
qT Soil total porosity NA (-)
capillary vadose foundationqwVolumetric water content NA NA NA (-)
qa Volumetric air content NA NA NA (-)
Kvs Vertical hydraulic conductivity NA (ft/yr)
kv Vapor permeability NA (ft^2)
Lgw Depth to groundwater NA (ft)
pH Soil/groundwater pH NA (-)
W Length of source-zone area parallel to wind NA (ft)
Wgw Length of source-zone area parallel to GW flow NA (ft)
Lss Thickness of affected surface soils NA (ft)
A Source zone area NA (ft^2)
Ls Depth to top of affected soils NA (ft)
Lbase Depth to base of affected soils NA (ft)
Lsubs Thickness of affected soils NA (ft)
Outdoor Air Parameters Value (Units)
Uair Ambient air velocity in mixing zone NA (ft/yr)dair Air mixing zone height NA (ft)
Q/C Inverse mean concentration at the center of source NA
Pa Areal particulate emission rate NA (g/cm^2/s)
V Fraction of vegetative cover NA
Um Mean annual airvelocity at 7m NA
Ut Equivalent 7m air velocity threshold value NA
F(x)Windspeed function dependant on Um/Ut NA
PEF Partculate Emission Factor NA
Building Parameters Residential Commercial (Units)
Lb Building volume/area ratio NA NA (ft)
Ab Foundation area NA NA (ft^2)
Xcrk Foundation perimeter NA NA (ft)
ER Building air exchange rate NA NA (1/yr)
Lcrk Foundation thickness NA NA (ft)
Zcrk Depth to bottom of foundation slab NA NA (ft)
h Foundation crack fraction NA NA (-)
dP Indoor/outdoor differential pressure NA NA (g/cm/s^2)
Qs Convective air flow through slab NA NA (ft^3/yr)
qwcrack Volumetric water content of cracks NA NA (-)qacrack Volumetric air content of cracks NA NA (-)
BV Building Volume NA NA (ft^3)
w Building Width Perpendicular to GW flow NA NA (ft)
L Building Length Parallel to GW flow NA NA (ft)
n Saturated Soil Zone Porosity NA NA (-)
Groundwater Parameters Value (Units)
dgw Groundwater mixing zone depth NA (ft)
If Net groundwater infiltration rate NA (cm/yr)
Ugw Groundwater Darcy velocity 1.60008 (ft/yr)
Vgw Groundwater seepage velocity 4.571657143 (ft/yr)
Ks Saturated hydraulic conductivity 141.6 (ft/yr)
i Groundwater gradient 0.0113 (-)
Sw Width of groundwater source zone 45 (ft)
Sd Depth of groundwater source zone 30 (ft)qeff Effective porosity in water-bearing unit 0.35 (-)
foc-sat Fraction organic carbon in water-bearing unit 0.001 (-)
pHsat Groundwater pH 9 (-)
Biodegradation considered?1st Order
Transport Parameters Off-site 1 Off-site 2 Off-site 1 Off-site 2 (Units)
Lateral Groundwater Transport Groundwater Ingestion Groundwater to Indoor AiraxLongitudinal dispersivity 7.2E+1 NA NA NA (ft)
ay Transverse dispersivity 2.4E+1 NA NA NA (ft)
az Vertical dispersivity 3.6E+0 NA NA NA (ft)
Lateral Outdoor Air Transport Soil to Outdoor Air Inhal.GW to Outdoor Air Inhal.FALSE
sy Transverse dispersion coefficient NA NA NA NA (ft)
sz Vertical dispersion coefficient NA NA NA NA (ft)
ADF Air dispersion factor NA NA NA NA (-)
Surface Water Parameters Off-site 2 (Units)
Qsw Surface water flowrate NA (ft^3/yr)
Wpi Width of GW plume at SW discharge NA (ft)
dpi Thickness of GW plume at SW discharge NA (ft)
DFsw Groundwater-to-surface water dilution factor NA (-)
NOTE: NA = Not applicable
Orange = Site-specific value (different from current default value)
Yellow = User-defined default value (different from RBCA Tool Kit default)
RBCA SITE ASSESSMENT
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT Tier 2 Domenico Groundwater Modeling Summary
Site Name: Lewis Service Station Site Location: 4733 Fallston Road, Fallston, North CarolinaCompleted By: Terracon Consultants, Inc. Date Completed: 16-Sep-21 1 OF 2
DOMENICO GROUNDWATER MODELING SUMMARY
OFF-SITE GROUNDWATER EXPOSURE PATHWAYS o (CHECKED IF PATHWAY IS ACTIVE)
SOILS LEACHING TO GROUNDWATER
1) Source Medium 2) Steady-state Exposure Concentration 3) POE Concentration Limit 4) Time to Reach POE Conc. Limit
Groundwater: POE Conc. (mg/L)Groundwater: POE Conc. (mg/L)Conc. limit reached? ("n" if yes) ; Time (yr)
Soil Conc.Off-site 1
(715 ft)
Off-site 2
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern (mg/kg)None None None None None None
Benzene NA NA
Toluene NA NA
Ethyl benzene NA NA
Xylenes (mixed isomers)NA NA
Ethylene dibromide NA NA
Methyl t-Butyl ether (MTBE)NA NA
NOTE: POE = Point of exposure
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT Tier 2 Domenico Groundwater Modeling Summary
Site Name: Lewis Service Station Site Location: 4733 Fallston Road, Fallston, North CarolinaCompleted By: Terracon Consultants, Inc. Date Completed: 16-Sep-21 2 OF 2
DOMENICO GROUNDWATER MODELING SUMMARY
OFF-SITE GROUNDWATER EXPOSURE PATHWAYS n (CHECKED IF PATHWAY IS ACTIVE)
GROUNDWATER:
INGESTION 1) Source Medium 2) Steady-state Exposure Concentration 3) POE Concentration Limit 4) Time to Reach POE Conc. Limit
Groundwater: POE Conc. (mg/L)Groundwater: POE Conc. (mg/L)Conc reaches limit? ("n" If yes) ; Time (yr)
Groundwater Off-site 1
(715 ft)
Off-site 2
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern Conc. (mg/L)Residential None Residential None Residential None
Benzene 3.2E-1 1.9E-12 4.5E-2 o NA NA
Toluene 2.4E+0 1.2E-66 1.3E+0 o NA NA
Ethyl benzene 3.3E-1 3.7E-26 1.6E+0 o NA NA
Xylenes (mixed isomers)4.0E+0 9.3E-21 3.1E+0 o NA NA
Ethylene dibromide 7.4E-2 2.8E-29 3.4E-4 o NA NA
Methyl t-Butyl ether (MTBE)1.3E-1 5.5E-16 1.6E-1 o NA NA
NOTE: POE = Point of exposure
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 1 of 6
Constiuent:Benzene
Source Medium:Affected Groundwater
Biodegredation:1st Order
Concentration vs. Distance from Source Time (yr)1.0 FALSE 0 Off-site1 Off-site2
(for given time)0.1 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 3.2E-1 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 3.2E-1 1.9E-3 4.5E-5 2.1E-6 1.5E-7 1.5E-8 1.9E-9 2.7E-10 4.7E-11 8.9E-12 1.9E-12 #####1.9E-12 NA
POE Concentration Limit (mg/L)4.5E-2 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-12
(for given distance from source)0 0 2.0E-12
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 7.7E-26 5.5E-19 6.9E-16 2.8E-14 2.2E-13 6.5E-13 1.2E-12 1.5E-12 1.7E-12 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 7.7E-26 5.5E-19 6.9E-16 2.8E-14 2.2E-13 6.5E-13 1.2E-12 1.5E-12 1.7E-12 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
5.0E-2
1.0E-1
1.5E-1
2.0E-1
2.5E-1
3.0E-1
3.5E-1
4.0E-1
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
5.0E-13
1.0E-12
1.5E-12
2.0E-12
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 2 of 6
Constiuent:Toluene
Source Medium:Affected Groundwater
Biodegredation:1st Order
Concentration vs. Distance from Source Time (yr)1.0 FALSE 3 Off-site1 Off-site2
(for given time)1 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 2.4E+0 4.8E-32 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 2.4E+0 1.5E-19 1.5E-28 1.8E-35 2.4E-41 1.7E-46 3.8E-51 2.0E-55 2.1E-59 4.0E-63 1.2E-66 #####1.2E-66 NA
POE Concentration Limit (mg/L)1.3E+0 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-66
(for given distance from source)0 0 2.0E-66
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 1.3E-77 1.2E-66 1.2E-66 1.2E-66 1.2E-66 1.2E-66 1.2E-66 1.2E-66 1.2E-66 1.2E-66 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 1.3E-77 1.2E-66 1.2E-66 1.2E-66 1.2E-66 1.2E-66 1.2E-66 1.2E-66 1.2E-66 1.2E-66 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
5.0E-1
1.0E+0
1.5E+0
2.0E+0
2.5E+0
3.0E+0
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
5.0E-67
1.0E-66
1.5E-66
2.0E-66
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 3 of 6
Constiuent:Ethyl benzene
Source Medium:Affected Groundwater
Biodegredation:1st Order
Concentration vs. Distance from Source Time (yr)1.0 FALSE 0 Off-site1 Off-site2
(for given time)0.1 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 3.3E-1 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 3.3E-1 1.7E-7 5.1E-11 9.1E-14 4.2E-16 3.7E-18 5.2E-20 1.0E-21 2.7E-23 9.0E-25 3.7E-26 #####3.7E-26 NA
POE Concentration Limit (mg/L)1.6E+0 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-26
(for given distance from source)0 0 4.0E-26
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 1.7E-40 2.0E-31 6.0E-28 1.2E-26 3.1E-26 3.6E-26 3.6E-26 3.7E-26 3.7E-26 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 1.7E-40 2.0E-31 6.0E-28 1.2E-26 3.1E-26 3.6E-26 3.6E-26 3.7E-26 3.7E-26 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
5.0E-2
1.0E-1
1.5E-1
2.0E-1
2.5E-1
3.0E-1
3.5E-1
4.0E-1
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
5.0E-27
1.0E-26
1.5E-26
2.0E-26
2.5E-26
3.0E-26
3.5E-26
4.0E-26
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 4 of 6
Constiuent:Xylenes (mixed isomers)
Source Medium:Affected Groundwater
Biodegredation:1st Order
Concentration vs. Distance from Source Time (yr)1.0 FALSE 5 Off-site1 Off-site2
(for given time)1 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 4.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 4.0E+0 4.2E-5 5.0E-8 2.5E-10 2.7E-12 5.0E-14 1.4E-15 5.1E-17 2.4E-18 1.4E-19 9.3E-21 #####9.3E-21 NA
POE Concentration Limit (mg/L)3.1E+0 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-21
(for given distance from source)0 0 1.0E-20
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 0.0E+0 8.8E-30 5.1E-25 1.1E-22 1.5E-21 5.0E-21 7.9E-21 9.1E-21 9.3E-21 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 0.0E+0 8.8E-30 5.1E-25 1.1E-22 1.5E-21 5.0E-21 7.9E-21 9.1E-21 9.3E-21 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
1.0E+0
2.0E+0
3.0E+0
4.0E+0
5.0E+0
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
2.0E-21
4.0E-21
6.0E-21
8.0E-21
1.0E-20
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 5 of 6
Constiuent:Ethylene dibromide
Source Medium:Affected Groundwater
Biodegredation:1st Order
Concentration vs. Distance from Source Time (yr)1.0 FALSE 0 Off-site1 Off-site2
(for given time)0.01 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 7.4E-2 1.8E-23 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 7.4E-2 6.5E-9 9.4E-13 9.3E-16 2.6E-18 1.5E-20 1.4E-22 2.0E-24 3.8E-26 9.2E-28 2.8E-29 #####2.8E-29 NA
POE Concentration Limit (mg/L)3.4E-4 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-29
(for given distance from source)0 0 3.0E-29
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 8.9E-33 1.2E-29 2.7E-29 2.8E-29 2.8E-29 2.8E-29 2.8E-29 2.8E-29 2.8E-29 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 8.9E-33 1.2E-29 2.7E-29 2.8E-29 2.8E-29 2.8E-29 2.8E-29 2.8E-29 2.8E-29 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
1.0E-2
2.0E-2
3.0E-2
4.0E-2
5.0E-2
6.0E-2
7.0E-2
8.0E-2
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
5.0E-30
1.0E-29
1.5E-29
2.0E-29
2.5E-29
3.0E-29
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 6 of 6
Constiuent:Methyl t-Butyl ether (MTBE)
Source Medium:Affected Groundwater
Biodegredation:1st Order
Concentration vs. Distance from Source Time (yr)1.0 FALSE 0 Off-site1 Off-site2
(for given time)0.1 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 1.3E-1 2.3E-19 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 1.3E-1 9.9E-5 8.5E-7 1.9E-8 7.2E-10 4.0E-11 3.0E-12 2.8E-13 3.0E-14 3.9E-15 5.5E-16 #####5.5E-16 NA
POE Concentration Limit (mg/L)1.6E-1 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-16
(for given distance from source)0 0 6.0E-16
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 2.4E-23 1.3E-18 7.5E-17 3.2E-16 5.0E-16 5.5E-16 5.5E-16 5.5E-16 5.5E-16 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 2.4E-23 1.3E-18 7.5E-17 3.2E-16 5.0E-16 5.5E-16 5.5E-16 5.5E-16 5.5E-16 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
5.0E-2
1.0E-1
1.5E-1
2.0E-1
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
1.0E-16
2.0E-16
3.0E-16
4.0E-16
5.0E-16
6.0E-16
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
1 OF 7
TIER 2 EXPOSURE CONCENTRATION AND INTAKE CALCULATION
GROUNDWATER EXPOSURE PATHWAYS o (Checked if Pathway is Complete)
SOILS : LEACHING TO
GROUNDWATER INGESTION 1) Source Medium 2) NAF Value (L/kg)3) Exposure Medium
Receptor Groundwater: POE Conc. (mg/L) (1)/(2)
Soil Conc.
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern (mg/kg)None Residential None None Residential None
Benzene
Toluene
Ethyl benzene
Xylenes (mixed isomers)
Ethylene dibromide
Methyl t-Butyl ether (MTBE)
* = Chemical with user-specified data
NOTE: NAF = Natural attenuation factor POE = Point of exposure
Site Name: Lewis Service Station Date Completed: 16-Sep-21
Site Location: 4733 Fallston Road, Fallston, North Carolina Job ID: 71179012A
Completed By: Terracon Consultants, Inc.
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
2 OF 7
TIER 2 EXPOSURE CONCENTRATION AND INTAKE CALCULATION
GROUNDWATER EXPOSURE PATHWAYS
SOILS : LEACHING TO
GROUNDWATER INGESTION (cont'd)4) Exposure Multiplier 5) Average Daily Intake Rate
(IRxEFxED)/(BWxAT) (L/kg-day)(mg/kg/day) (3) x (4)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern None Residential None None Residential None
Benzene
Toluene
Ethyl benzene
Xylenes (mixed isomers)
Ethylene dibromide
Methyl t-Butyl ether (MTBE)
* = Chemical with user-specified data
NOTE: AT = Averaging time (days)ED = Exposure duration (yr)IR = Ingestion rate (mg/day)
BW = Body weight (kg)EF = Exposure frequency (days/yr)
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North Carolina Date Completed: 16-Sep-21
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
3 OF 7
TIER 2 EXPOSURE CONCENTRATION AND INTAKE CALCULATION
GROUNDWATER EXPOSURE PATHWAYS n (Checked if Pathway is Complete)
GROUNDWATER: INGESTION
1) Source Medium 2) NAF Value (unitless)3) Exposure Medium
Receptor Groundwater: POE Conc. (mg/L) (1)/(2)
Groundwater
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern Conc. (mg/L)None Residential None None Residential None
Benzene 3.2E-1 1.7E+11 1.9E-12
Toluene 2.4E+0 2.0E+66 1.2E-66
Ethyl benzene 3.3E-1 9.0E+24 3.7E-26
Xylenes (mixed isomers)4.0E+0 4.3E+20 9.3E-21
Ethylene dibromide 7.4E-2 2.7E+27 2.8E-29
Methyl t-Butyl ether (MTBE)1.3E-1 2.4E+14 5.5E-16
NOTE: NAF = Natural attenuation factor POE = Point of exposure
Site Name: Lewis Service Station Date Completed: 16-Sep-21
Site Location: 4733 Fallston Road, Fallston, North Carolina Job ID: 71179012A
Completed By: Terracon Consultants, Inc.
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
4 OF 7
TIER 2 EXPOSURE CONCENTRATION AND INTAKE CALCULATION
GROUNDWATER EXPOSURE PATHWAYS
GROUNDWATER INGESTION (cont'd)
4) Exposure Multiplier 5) Average Daily Intake Rate
(IRxEFxED)/(BWxAT) (L/kg/day)(mg/kg/day) (3) x (4)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern None Residential None None Residential None
Benzene 1.5E-2 2.8E-14
Toluene 6.4E-2 7.6E-68
Ethyl benzene 6.4E-2 2.3E-27
Xylenes (mixed isomers)6.4E-2 6.0E-22
Ethylene dibromide 1.5E-2 4.1E-31
Methyl t-Butyl ether (MTBE)1.5E-2 8.2E-18
* = Chemical with user-specified data
NOTE: AT = Averaging time (days)ED = Exposure duration (yr)IR = Ingestion rate (mg/day)
BW = Body weight (kg)EF = Exposure frequency (days/yr)
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North Carolina Date Completed: 16-Sep-21
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
5 OF 7
TIER 2 EXPOSURE CONCENTRATION AND INTAKE CALCULATION
GROUNDWATER EXPOSURE PATHWAYS
MAXIMUM PATHWAY INTAKE (mg/kg/day)
(Maximum intake of active pathways
soil leaching & groundwater routes.)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern None Residential None
Benzene 2.8E-14
Toluene 7.6E-68
Ethyl benzene 2.3E-27
Xylenes (mixed isomers)6.0E-22
Ethylene dibromide 4.1E-31
Methyl t-Butyl ether (MTBE)8.2E-18
* = Chemical with user-specified data
Site Name: Lewis Service Station Date Completed: 16-Sep-21
Site Location: 4733 Fallston Road, Fallston, North Carolina Job ID: 71179012A
Completed By: Terracon Consultants, Inc.
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
6 OF 7
TIER 2 PATHWAY RISK CALCULATION
GROUNDWATER EXPOSURE PATHWAYS n (Checked if Pathway is Complete)
CARCINOGENIC RISK
(1) Is (2) Maximum Carcinogenic (3) Oral (4) Individual COC
Carcinogenic Intake Rate (mg/kg/day)Slope Factor Risk (2) x (3)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
(mg/kg-day)^-1 On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern None Residential None None Residential None
Benzene TRUE 2.8E-14 1.5E-2 4.1E-16
Toluene FALSE -
Ethyl benzene FALSE -
Xylenes (mixed isomers)FALSE -
Ethylene dibromide TRUE 4.1E-31 2.0E+0 8.3E-31
Methyl t-Butyl ether (MTBE)TRUE 8.2E-18 1.8E-3 1.5E-20
Total Pathway Carcinogenic Risk =4.1E-16
Site Name: Lewis Service Station Date Completed: 16-Sep-21
Site Location: 4733 Fallston Road, Fallston, North Carolina Job ID: 71179012A
Completed By: Terracon Consultants, Inc.
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
7 OF 7
TIER 2 PATHWAY RISK CALCULATION
GROUNDWATER EXPOSURE PATHWAYS n (Checked if Pathway is Complete)
TOXIC EFFECTS
(5) Maximum Toxicant (6) Oral (7) Individual COC
Intake Rate (mg/kg/day)Reference Hazard Quotient (5) / (6)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Dose
(mg/kg/day)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern None Residential None None Residential None
Benzene 1.2E-13 4.0E-3 3.0E-11
Toluene 7.6E-68 8.0E-2 9.5E-67
Ethyl benzene 2.3E-27 1.0E-1 2.3E-26
Xylenes (mixed isomers)6.0E-22 2.0E-1 3.0E-21
Ethylene dibromide 1.8E-30 9.0E-3 2.0E-28
Methyl t-Butyl ether (MTBE)3.5E-17 1.0E-2 3.5E-15
Total Pathway Hazard Index =3.0E-11
Site Name: Lewis Service Station Date Completed: 16-Sep-21
Site Location: 4733 Fallston Road, Fallston, North Carolina Job ID: 71179012A
Completed By: Terracon Consultants, Inc.
RBCA Tool Kit for Chemical Releases, Version 2.6
Input Parameter Summary
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.
Site Location: 4733 Fallston Road, Fallston, North Carolina Date Completed: 16-Sep-21
Exposure Parameters Residential User Defined
Child*Adolescent Adult Age Adjusted**Adult Construct.
ATc Averaging time for carcinogens (yr)70 70 70 NA 70 70 -
ATn Averaging time for non-carcinogens (yr)6 12 30 NA 25 1 -
BW Body weight (kg)15 35 70 NA 70 70 -
ED Exposure duration (yr)6 12 30 NA 25 1 -
t Averaging time for vapor flux (yr)30 30 30 NA 30 30 -
EF Exposure frequency (days/yr)350 350 350 NA 250 180 -
EFD Exposure frequency for dermal exposure 350 350 350 NA 250 180 -
IRw Ingestion rate of water (L/day)1 1 2 2.5 1 NA -
IRs Ingestion rate of soil (mg/day)200 200 100 387 50 100 -
SA Skin surface area (dermal) (cm^2)2023 2023 3160 4771 3160 3160 -
M Soil to skin adherence factor 0.5 0.5 0.5 NA 0.5 0.5 -
ETswim Swimming exposure time (hr/event)1 3 3 NA NA NA NA
EVswim Swimming event frequency (events/yr)12 12 12 NA NA NA NA
IRswim Water ingestion while swimming (L/hr)0.5 0.5 0.05 0.3 NA NA NA
SAswim Skin surface area for swimming (cm^2)3500 8100 23000 15680 NA NA NA
IRfish Ingestion rate of fish (kg/yr)0.025 0.025 0.025 0.053 NA NA NA
FIfish Contaminated fish fraction (unitless)1 1 1 NA NA NA NA
IRbg Below-ground vegetable ingestion 0.002 0.002 0.006 2.053 NA NA NA
IRabg Above-ground vegetable ingestion 0.001 0.001 0.002 0.887 NA NA NA
VGbg Above-ground Veg. Ingest. Correction Factor 0.01 0.01 0.01 NA NA NA NA
VGabg Below-ground Veg. Ingest. Correction Factor 0.01 0.01 0.01 NA NA NA NA
* = Child Receptor used for Non-Carcinogens
** = Age-adjusted rate is effective value corresponding to adult exposure factors.
Complete Exposure Pathways and Receptors On-site Off-site 1 Off-site 2
Groundwater:
Groundwater Ingestion None Residential None
Soil Leaching to Groundwater Ingestion None None None
Apply MCL Values No No No
Applicable Surface Water Exposure Routes:
Swimming NA NA None
Fish Consumption NA NA None
Aquatic Life Protection NA NA None
Soil:
Direct Contact: direct combined pathways None NA NA
Apply CLEA- UK SGV levels
Outdoor Air:
Particulates from Surface Soils None None None
Volatilization from Soils None None None
Volatilization from Groundwater None None None
Indoor Air:
Volatilization from Soils None NA NA
Volatilization from Groundwater None None None
Soil Leaching to Groundwater Volatilization None None None
Receptor Distance from Source Media On-site Off-site 1 Off-site 2 (Units)
Groundwater receptor NA 715 NA (ft)
Outdoor air inhalation receptor NA NA NA (ft)
Indoor air inhalation receptor NA NA NA (ft)
Target Health Risk Values Individual Cumulative
TR Target Risk (carcinogens)1.0E-5 1.0E-5
THQ Target Hazard Quotient (non-carcinogenic risk)1.0E+0 1.0E+0
Modeling Options
RBCA tier Tier 2
Outdoor air volatilization model NA
Indoor air volatilization model NA
Soil leaching model NA
Use soil attenuation model (SAM) for leachate? NA
Use dual equilibrium desorption model? NA
Apply Mass Balance Limit for Soil Volatilization? NA
Apply UK (CLEA) SGV as soil concentration limit No
Vegetable calculation options NA
Air dilution factor NA
Groundwater dilution-attenuation factor Domenico model
NOTE: NA = Not applicable
Yellow = User-defined default value (different from RBCA Tool Kit default)
Orange = Site-specific value (different from current default value)
No
RBCA SITE ASSESSMENT
Commercial/Industrial
RBCA Tool Kit for Chemical Releases, Version 2.6
Input Parameter Summary
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.
Site Location: 4733 Fallston Road, Fallston, North Carolina Date Completed: 16-Sep-21
Surface Soil Column Parameters Value (Units)
hcap Capillary zone thickness NA (ft)
hv Vadose zone thickness NA (ft)
rs Soil bulk density NA (g/cm^3)
foc Fraction organic carbon NA (-)
qT Soil total porosity NA (-)
capillary vadose foundationqwVolumetric water content NA NA NA (-)
qa Volumetric air content NA NA NA (-)
Kvs Vertical hydraulic conductivity NA (ft/yr)
kv Vapor permeability NA (ft^2)
Lgw Depth to groundwater NA (ft)
pH Soil/groundwater pH NA (-)
W Length of source-zone area parallel to wind NA (ft)
Wgw Length of source-zone area parallel to GW flow NA (ft)
Lss Thickness of affected surface soils NA (ft)
A Source zone area NA (ft^2)
Ls Depth to top of affected soils NA (ft)
Lbase Depth to base of affected soils NA (ft)
Lsubs Thickness of affected soils NA (ft)
Outdoor Air Parameters Value (Units)
Uair Ambient air velocity in mixing zone NA (ft/yr)dair Air mixing zone height NA (ft)
Q/C Inverse mean concentration at the center of source NA
Pa Areal particulate emission rate NA (g/cm^2/s)
V Fraction of vegetative cover NA
Um Mean annual airvelocity at 7m NA
Ut Equivalent 7m air velocity threshold value NA
F(x)Windspeed function dependant on Um/Ut NA
PEF Partculate Emission Factor NA
Building Parameters Residential Commercial (Units)
Lb Building volume/area ratio NA NA (ft)
Ab Foundation area NA NA (ft^2)
Xcrk Foundation perimeter NA NA (ft)
ER Building air exchange rate NA NA (1/yr)
Lcrk Foundation thickness NA NA (ft)
Zcrk Depth to bottom of foundation slab NA NA (ft)
h Foundation crack fraction NA NA (-)
dP Indoor/outdoor differential pressure NA NA (g/cm/s^2)
Qs Convective air flow through slab NA NA (ft^3/yr)
qwcrack Volumetric water content of cracks NA NA (-)qacrack Volumetric air content of cracks NA NA (-)
BV Building Volume NA NA (ft^3)
w Building Width Perpendicular to GW flow NA NA (ft)
L Building Length Parallel to GW flow NA NA (ft)
n Saturated Soil Zone Porosity NA NA (-)
Groundwater Parameters Value (Units)
dgw Groundwater mixing zone depth NA (ft)
If Net groundwater infiltration rate NA (cm/yr)
Ugw Groundwater Darcy velocity 1.60008 (ft/yr)
Vgw Groundwater seepage velocity 4.571657143 (ft/yr)
Ks Saturated hydraulic conductivity 141.6 (ft/yr)
i Groundwater gradient 0.0113 (-)
Sw Width of groundwater source zone 45 (ft)
Sd Depth of groundwater source zone 30 (ft)qeff Effective porosity in water-bearing unit 0.35 (-)
foc-sat Fraction organic carbon in water-bearing unit 0.001 (-)
pHsat Groundwater pH 9 (-)
Biodegradation considered?No
Transport Parameters Off-site 1 Off-site 2 Off-site 1 Off-site 2 (Units)
Lateral Groundwater Transport Groundwater Ingestion Groundwater to Indoor AiraxLongitudinal dispersivity 7.2E+1 NA NA NA (ft)
ay Transverse dispersivity 2.4E+1 NA NA NA (ft)
az Vertical dispersivity 3.6E+0 NA NA NA (ft)
Lateral Outdoor Air Transport Soil to Outdoor Air Inhal.GW to Outdoor Air Inhal.FALSE
sy Transverse dispersion coefficient NA NA NA NA (ft)
sz Vertical dispersion coefficient NA NA NA NA (ft)
ADF Air dispersion factor NA NA NA NA (-)
Surface Water Parameters Off-site 2 (Units)
Qsw Surface water flowrate NA (ft^3/yr)
Wpi Width of GW plume at SW discharge NA (ft)
dpi Thickness of GW plume at SW discharge NA (ft)
DFsw Groundwater-to-surface water dilution factor NA (-)
NOTE: NA = Not applicable
Orange = Site-specific value (different from current default value)
Yellow = User-defined default value (different from RBCA Tool Kit default)
RBCA SITE ASSESSMENT
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT Tier 2 Domenico Groundwater Modeling Summary
Site Name: Lewis Service Station Site Location: 4733 Fallston Road, Fallston, North CarolinaCompleted By: Terracon Consultants, Inc. Date Completed: 16-Sep-21 1 OF 2
DOMENICO GROUNDWATER MODELING SUMMARY
OFF-SITE GROUNDWATER EXPOSURE PATHWAYS o (CHECKED IF PATHWAY IS ACTIVE)
SOILS LEACHING TO GROUNDWATER
1) Source Medium 2) Steady-state Exposure Concentration 3) POE Concentration Limit 4) Time to Reach POE Conc. Limit
Groundwater: POE Conc. (mg/L)Groundwater: POE Conc. (mg/L)Conc. limit reached? ("n" if yes) ; Time (yr)
Soil Conc.Off-site 1
(715 ft)
Off-site 2
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern (mg/kg)None None None None None None
Benzene NA NA
Toluene NA NA
Ethyl benzene NA NA
Xylenes (mixed isomers)NA NA
Ethylene dibromide NA NA
Methyl t-Butyl ether (MTBE)NA NA
NOTE: POE = Point of exposure
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT Tier 2 Domenico Groundwater Modeling Summary
Site Name: Lewis Service Station Site Location: 4733 Fallston Road, Fallston, North CarolinaCompleted By: Terracon Consultants, Inc. Date Completed: 16-Sep-21 2 OF 2
DOMENICO GROUNDWATER MODELING SUMMARY
OFF-SITE GROUNDWATER EXPOSURE PATHWAYS n (CHECKED IF PATHWAY IS ACTIVE)
GROUNDWATER:
INGESTION 1) Source Medium 2) Steady-state Exposure Concentration 3) POE Concentration Limit 4) Time to Reach POE Conc. Limit
Groundwater: POE Conc. (mg/L)Groundwater: POE Conc. (mg/L)Conc reaches limit? ("n" If yes) ; Time (yr)
Groundwater Off-site 1
(715 ft)
Off-site 2
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern Conc. (mg/L)Residential None Residential None Residential None
Benzene 3.2E-1 1.0E-2 4.5E-2 o NA NA
Toluene 2.4E+0 7.6E-2 1.3E+0 o NA NA
Ethyl benzene 3.3E-1 1.0E-2 1.6E+0 o NA NA
Xylenes (mixed isomers)4.0E+0 1.3E-1 3.1E+0 o NA NA
Ethylene dibromide 7.4E-2 2.3E-3 3.4E-4 n 1.2E+2 NA
Methyl t-Butyl ether (MTBE)1.3E-1 4.2E-3 1.6E-1 o NA NA
NOTE: POE = Point of exposure
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 1 of 6
Constiuent:Benzene
Source Medium:Affected Groundwater
Biodegredation:None
Concentration vs. Distance from Source Time (yr)1.0 FALSE 0 Off-site1 Off-site2
(for given time)0.1 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 3.2E-1 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 3.2E-1 2.5E-1 1.4E-1 8.4E-2 5.4E-2 3.7E-2 2.6E-2 2.0E-2 1.5E-2 1.2E-2 1.0E-2 #####1.0E-2 NA
POE Concentration Limit (mg/L)4.5E-2 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-06
(for given distance from source)0 0 3.0E-6
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 0.0E+0 7.1E-17 4.3E-13 8.1E-11 2.7E-9 3.2E-8 2.1E-7 9.0E-7 2.9E-6 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 0.0E+0 7.1E-17 4.3E-13 8.1E-11 2.7E-9 3.2E-8 2.1E-7 9.0E-7 2.9E-6 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
5.0E-2
1.0E-1
1.5E-1
2.0E-1
2.5E-1
3.0E-1
3.5E-1
4.0E-1
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
5.0E-7
1.0E-6
1.5E-6
2.0E-6
2.5E-6
3.0E-6
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 2 of 6
Constiuent:Toluene
Source Medium:Affected Groundwater
Biodegredation:None
Concentration vs. Distance from Source Time (yr)1.0 FALSE 3 Off-site1 Off-site2
(for given time)1 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 2.4E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 2.4E+0 1.9E+0 1.1E+0 6.3E-1 4.1E-1 2.8E-1 2.0E-1 1.5E-1 1.2E-1 9.3E-2 7.6E-2 #####7.6E-2 NA
POE Concentration Limit (mg/L)1.3E+0 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-06
(for given distance from source)0 0 2.0E-6
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 0.0E+0 0.0E+0 2.7E-15 2.0E-12 1.7E-10 4.1E-9 4.5E-8 2.9E-7 1.3E-6 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 0.0E+0 0.0E+0 2.7E-15 2.0E-12 1.7E-10 4.1E-9 4.5E-8 2.9E-7 1.3E-6 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
5.0E-1
1.0E+0
1.5E+0
2.0E+0
2.5E+0
3.0E+0
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
5.0E-7
1.0E-6
1.5E-6
2.0E-6
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 3 of 6
Constiuent:Ethyl benzene
Source Medium:Affected Groundwater
Biodegredation:None
Concentration vs. Distance from Source Time (yr)1.0 FALSE 0 Off-site1 Off-site2
(for given time)0.1 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 3.3E-1 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 3.3E-1 2.6E-1 1.5E-1 8.8E-2 5.6E-2 3.8E-2 2.8E-2 2.1E-2 1.6E-2 1.3E-2 1.0E-2 #####1.0E-2 NA
POE Concentration Limit (mg/L)1.6E+0 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-08
(for given distance from source)0 0 2.0E-8
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 0.0E+0 0.0E+0 5.8E-19 2.1E-15 3.9E-13 1.7E-11 2.8E-10 2.5E-9 1.5E-8 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 0.0E+0 0.0E+0 5.8E-19 2.1E-15 3.9E-13 1.7E-11 2.8E-10 2.5E-9 1.5E-8 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
5.0E-2
1.0E-1
1.5E-1
2.0E-1
2.5E-1
3.0E-1
3.5E-1
4.0E-1
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
5.0E-9
1.0E-8
1.5E-8
2.0E-8
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 4 of 6
Constiuent:Xylenes (mixed isomers)
Source Medium:Affected Groundwater
Biodegredation:None
Concentration vs. Distance from Source Time (yr)1.0 FALSE 5 Off-site1 Off-site2
(for given time)1 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 4.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 4.0E+0 3.1E+0 1.8E+0 1.1E+0 6.8E-1 4.7E-1 3.4E-1 2.5E-1 2.0E-1 1.6E-1 1.3E-1 #####1.3E-1 NA
POE Concentration Limit (mg/L)3.1E+0 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-08
(for given distance from source)0 0 5.0E-8
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 1.6E-15 4.8E-13 2.8E-11 6.1E-10 6.6E-9 4.5E-8 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 1.6E-15 4.8E-13 2.8E-11 6.1E-10 6.6E-9 4.5E-8 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
1.0E+0
2.0E+0
3.0E+0
4.0E+0
5.0E+0
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
1.0E-8
2.0E-8
3.0E-8
4.0E-8
5.0E-8
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 5 of 6
Constiuent:Ethylene dibromide
Source Medium:Affected Groundwater
Biodegredation:None
Concentration vs. Distance from Source Time (yr)1.0 FALSE 0 Off-site1 Off-site2
(for given time)0.01 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 7.4E-2 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 7.4E-2 5.7E-2 3.3E-2 2.0E-2 1.3E-2 8.5E-3 6.1E-3 4.6E-3 3.6E-3 2.9E-3 2.3E-3 #####2.3E-3 NA
POE Concentration Limit (mg/L)3.4E-4 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-06
(for given distance from source)0 0 2.0E-6
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 0.0E+0 8.0E-17 3.3E-13 4.9E-11 1.4E-9 1.5E-8 8.8E-8 3.5E-7 1.1E-6 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 0.0E+0 8.0E-17 3.3E-13 4.9E-11 1.4E-9 1.5E-8 8.8E-8 3.5E-7 1.1E-6 Off-site1 123.1
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
1.0E-2
2.0E-2
3.0E-2
4.0E-2
5.0E-2
6.0E-2
7.0E-2
8.0E-2
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
5.0E-7
1.0E-6
1.5E-6
2.0E-6
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT TIER 2 TRANSIENT DOMENICO ANALYSIS
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North CarolinaDate Completed: 16-Sep-21 6 of 6
Constiuent:Methyl t-Butyl ether (MTBE)
Source Medium:Affected Groundwater
Biodegredation:None
Concentration vs. Distance from Source Time (yr)1.0 FALSE 0 Off-site1 Off-site2
(for given time)0.1 ##Residential None
Distance (ft)0 71.5 143 214.5 286 357.5 429 500.5 572 643.5 715 ###715 NA
t = 1.0 yr 1.3E-1 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 0.0E+0 ###0.0E+0 NA
Steady-state 1.3E-1 1.0E-1 5.8E-2 3.5E-2 2.2E-2 1.5E-2 1.1E-2 8.2E-3 6.4E-3 5.1E-3 4.2E-3 #####4.2E-3 NA
POE Concentration Limit (mg/L)1.6E-1 NA
t = 1.0 yr
Concentration vs. Time Distance (ft)715 1E-06
(for given distance from source)0 0 9.0E-6
Time (yr)0 5 10 15 20 25 30 35 40 45 50 50 Time to Reach
x = 715 ft 0.0E+0 0.0E+0 0.0E+0 2.3E-14 2.6E-11 1.8E-9 3.1E-8 2.3E-7 1.1E-6 3.4E-6 8.7E-6 #####Conc. Limit (yr)
Off-site1 (715 ft)0.0E+0 0.0E+0 0.0E+0 2.3E-14 2.6E-11 1.8E-9 3.1E-8 2.3E-7 1.1E-6 3.4E-6 8.7E-6 Off-site1 NA
Off-site2 (0 ft)NA NA NA NA NA NA NA NA NA NA NA Off-site2 NA
x = 715 ftConc.(mg/L)Conc.(mg/L)0.0E+0
5.0E-2
1.0E-1
1.5E-1
2.0E-1
0 100 200 300 400 500 600 700Conc.(mg/L)Distance
Steady-state
t = 1.0 yr
Off-site1 Conc.Limit
Off-site2 Conc.Limit
0.0E+0
1.0E-6
2.0E-6
3.0E-6
4.0E-6
5.0E-6
6.0E-6
7.0E-6
8.0E-6
9.0E-6
0 5 10 15 20 25 30 35 40 45 50Conc.(mg/L)Time (yr)
x = 715 ft
Off-site1 (715 ft)
Off-site2 (0 ft)
Off-site1 Conc.Limit
Off-site2 Conc.Limit
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
1 OF 7
TIER 2 EXPOSURE CONCENTRATION AND INTAKE CALCULATION
GROUNDWATER EXPOSURE PATHWAYS o (Checked if Pathway is Complete)
SOILS : LEACHING TO
GROUNDWATER INGESTION 1) Source Medium 2) NAF Value (L/kg)3) Exposure Medium
Receptor Groundwater: POE Conc. (mg/L) (1)/(2)
Soil Conc.
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern (mg/kg)None Residential None None Residential None
Benzene
Toluene
Ethyl benzene
Xylenes (mixed isomers)
Ethylene dibromide
Methyl t-Butyl ether (MTBE)
* = Chemical with user-specified data
NOTE: NAF = Natural attenuation factor POE = Point of exposure
Site Name: Lewis Service Station Date Completed: 16-Sep-21
Site Location: 4733 Fallston Road, Fallston, North Carolina Job ID: 71179012A
Completed By: Terracon Consultants, Inc.
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
2 OF 7
TIER 2 EXPOSURE CONCENTRATION AND INTAKE CALCULATION
GROUNDWATER EXPOSURE PATHWAYS
SOILS : LEACHING TO
GROUNDWATER INGESTION (cont'd)4) Exposure Multiplier 5) Average Daily Intake Rate
(IRxEFxED)/(BWxAT) (L/kg-day)(mg/kg/day) (3) x (4)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern None Residential None None Residential None
Benzene
Toluene
Ethyl benzene
Xylenes (mixed isomers)
Ethylene dibromide
Methyl t-Butyl ether (MTBE)
* = Chemical with user-specified data
NOTE: AT = Averaging time (days)ED = Exposure duration (yr)IR = Ingestion rate (mg/day)
BW = Body weight (kg)EF = Exposure frequency (days/yr)
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North Carolina Date Completed: 16-Sep-21
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
3 OF 7
TIER 2 EXPOSURE CONCENTRATION AND INTAKE CALCULATION
GROUNDWATER EXPOSURE PATHWAYS n (Checked if Pathway is Complete)
GROUNDWATER: INGESTION
1) Source Medium 2) NAF Value (unitless)3) Exposure Medium
Receptor Groundwater: POE Conc. (mg/L) (1)/(2)
Groundwater
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern Conc. (mg/L)None Residential None None Residential None
Benzene 3.2E-1 3.2E+1 1.0E-2
Toluene 2.4E+0 3.2E+1 7.6E-2
Ethyl benzene 3.3E-1 3.2E+1 1.0E-2
Xylenes (mixed isomers)4.0E+0 3.2E+1 1.3E-1
Ethylene dibromide 7.4E-2 3.2E+1 2.3E-3
Methyl t-Butyl ether (MTBE)1.3E-1 3.2E+1 4.2E-3
NOTE: NAF = Natural attenuation factor POE = Point of exposure
Site Name: Lewis Service Station Date Completed: 16-Sep-21
Site Location: 4733 Fallston Road, Fallston, North Carolina Job ID: 71179012A
Completed By: Terracon Consultants, Inc.
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
4 OF 7
TIER 2 EXPOSURE CONCENTRATION AND INTAKE CALCULATION
GROUNDWATER EXPOSURE PATHWAYS
GROUNDWATER INGESTION (cont'd)
4) Exposure Multiplier 5) Average Daily Intake Rate
(IRxEFxED)/(BWxAT) (L/kg/day)(mg/kg/day) (3) x (4)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern None Residential None None Residential None
Benzene 1.5E-2 1.5E-4
Toluene 6.4E-2 4.8E-3
Ethyl benzene 6.4E-2 6.7E-4
Xylenes (mixed isomers)6.4E-2 8.2E-3
Ethylene dibromide 1.5E-2 3.5E-5
Methyl t-Butyl ether (MTBE)1.5E-2 6.2E-5
* = Chemical with user-specified data
NOTE: AT = Averaging time (days)ED = Exposure duration (yr)IR = Ingestion rate (mg/day)
BW = Body weight (kg)EF = Exposure frequency (days/yr)
Site Name: Lewis Service Station Completed By: Terracon Consultants, Inc.Job ID: 71179012A
Site Location: 4733 Fallston Road, Fallston, North Carolina Date Completed: 16-Sep-21
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
5 OF 7
TIER 2 EXPOSURE CONCENTRATION AND INTAKE CALCULATION
GROUNDWATER EXPOSURE PATHWAYS
MAXIMUM PATHWAY INTAKE (mg/kg/day)
(Maximum intake of active pathways
soil leaching & groundwater routes.)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern None Residential None
Benzene 1.5E-4
Toluene 4.8E-3
Ethyl benzene 6.7E-4
Xylenes (mixed isomers)8.2E-3
Ethylene dibromide 3.5E-5
Methyl t-Butyl ether (MTBE)6.2E-5
* = Chemical with user-specified data
Site Name: Lewis Service Station Date Completed: 16-Sep-21
Site Location: 4733 Fallston Road, Fallston, North Carolina Job ID: 71179012A
Completed By: Terracon Consultants, Inc.
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
6 OF 7
TIER 2 PATHWAY RISK CALCULATION
GROUNDWATER EXPOSURE PATHWAYS n (Checked if Pathway is Complete)
CARCINOGENIC RISK
(1) Is (2) Maximum Carcinogenic (3) Oral (4) Individual COC
Carcinogenic Intake Rate (mg/kg/day)Slope Factor Risk (2) x (3)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
(mg/kg-day)^-1 On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern None Residential None None Residential None
Benzene TRUE 1.5E-4 1.5E-2 2.2E-6
Toluene FALSE -
Ethyl benzene FALSE -
Xylenes (mixed isomers)FALSE -
Ethylene dibromide TRUE 3.5E-5 2.0E+0 7.0E-5
Methyl t-Butyl ether (MTBE)TRUE 6.2E-5 1.8E-3 1.1E-7
Total Pathway Carcinogenic Risk =7.2E-5
Site Name: Lewis Service Station Date Completed: 16-Sep-21
Site Location: 4733 Fallston Road, Fallston, North Carolina Job ID: 71179012A
Completed By: Terracon Consultants, Inc.
RBCA Tool Kit for Chemical Releases, Version 2.6
RBCA SITE ASSESSMENT
7 OF 7
TIER 2 PATHWAY RISK CALCULATION
GROUNDWATER EXPOSURE PATHWAYS n (Checked if Pathway is Complete)
TOXIC EFFECTS
(5) Maximum Toxicant (6) Oral (7) Individual COC
Intake Rate (mg/kg/day)Reference Hazard Quotient (5) / (6)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Dose
(mg/kg/day)
On-site
(0 ft)
Off-site 1
(715 ft)
Off-site 2
(0 ft)
Constituents of Concern None Residential None None Residential None
Benzene 6.4E-4 4.0E-3 1.6E-1
Toluene 4.8E-3 8.0E-2 6.1E-2
Ethyl benzene 6.7E-4 1.0E-1 6.7E-3
Xylenes (mixed isomers)8.2E-3 2.0E-1 4.1E-2
Ethylene dibromide 1.5E-4 9.0E-3 1.7E-2
Methyl t-Butyl ether (MTBE)2.7E-4 1.0E-2 2.7E-2
Total Pathway Hazard Index =3.1E-1
Site Name: Lewis Service Station Date Completed: 16-Sep-21
Site Location: 4733 Fallston Road, Fallston, North Carolina Job ID: 71179012A
Completed By: Terracon Consultants, Inc.