MO-7050_27776_CA_RPTS_20230728_RDC

1567 CF Pours
Harrisonburg, VA 22802
www.astenvironmental.com

July 28, 2023

Mr. Ben Ashba
Catlin Engineers
220 Old Dairy Road
Wilmington, NC 28405

RE: Quantitative High Resolution Site Characterization Report
Best Stop #2
10018 Lancaster Highway
Waxhaw, Monroe County, North Carolina
Dear Mr. Ashba,

AST Environmental, Inc. (AST) appreciates the opportunity collaborate with Catlin and NCDEQ
to the complete the Quantitative High Resolution Site Characterization (qHRSC) at the above
referenced location. The proposed scope of work was to complete 7 soil borings to approximately
50 ft-bgs. The overall goal of this qHRSC program is to:

1. Quantify the TVPH and benzene soil concentrations.
2. Provide a visual interpolation of a high-resolution data set to aide in future investigation
and remedial activities.
3. Design a BOS 200+ injection plan to bring groundwater concentrations in compliance with
regulatory requirements.

This letter report provides a summary of field activities during the RDC and an overview of
analytical soil and groundwater data.

REMEDIAL DESIGN CHARACTERIZATION

On May 17, 2023 AST mobilized to the site to begin direct push drilling with the Geologic
Exploration (GEX) drilling team. During the RDC event, a total of 7 soil borings were advanced
via direct push drilling by GEX using their Geoprobe 3230DT. At each boring location, a 3.75 inch
diameter direct push, dual tube tooling was advanced in five foot runs. Samples were collected
every two feet beginning at PID or olfactory presence of hydrocarbon mass. All intervals were
logged for lithology and PID readings were collected to guide the sampling process. Soil samples
were collected and shipped to the RPI Project Support Laboratory in Golden, CO for VOC and
Total Volatile Petroleum Hydrocarbon (TVPH) analysis via EPA method 8260B. Although this data
is used for injection design purposes, the lab is not a certified or accredited laboratory, this data
should not be used for regulator or compliance purposes.

Existing monitoring wells MW-01, MW-02, MW-04, MW-05, MW-07R, OW-04N and RW-01 were
developed and sampled. Groundwater samples were shipped to the RPI Project Support
Laboratory in Golden, CO for VOC and Total Volatile Petroleum Hydrocarbon (TVPH) analysis
via EPA method 8260B, anions via EPA method 300.1 and dissolved gases via EPA method RSK
175. Groundwater data has been tabulated and is included in the attachments as Table 2.

Historically, MW-01 has consistently shown benzene concentrations greater than 5,000 ug/L, with
the remaining wells in the network consistently above 1 ug/L. Select results from the RDC have
been tabulated within this report and can be found below. According to the ITRC LNAPL
Guidance Document, TVPH concentrations indicative of residual LNAPL in the subsurface are
Mr. Ben Ashba
July 28, 2023
Page 2

between 250 and 500 mg/kg, depending on the soil type. TVPH concentrations observed at this
site range from less than 0.5 to over 16,000 mg/kg TVPH, with RDC-01, RDC-03 and RDC-06
displaying the highest concentrations.

Boring logs for each location are included in Attachment B.

RDC-01 Soil Concentrations
Sample Depth Benzene (ug/kg) TVPH (mg/kg)
11 <10 <10
13 <10 <10
15 <10 <10
17 <10 <10
19 <10 <10
21 <10 <10
23 <10 <10
25 <10 <10
27 <10 <10
29 <250 700
31 <250 590
33 <500 1900
35 750 1300
37 5000 1300
39 1400 68
41 130 <50
43 33 10
45 26 <10
47 <10 <10
49 <0.5 <0.5

RDC-03 Soil Concentrations
Sample Depth Benzene (ug/kg) TVPH (mg/kg)
11 <0.5 <0.5
13 <0.5 <0.5
15 <0.5 <0.5
17 <0.5 0.7
19 0.8 2.1
21 4.6 5
23 <0.5 0.9
25 <0.5 <0.5
27 <0.5 1
29 <10 <10
31 110 330
33 170 1400
35 1100 650
37 770 370
39 690 70
41 220 7.7
43 72 16
45 35 5.3
47 5.1 2.5
49 9.5 3.3

Mr. Ben Ashba
July 28, 2023
Page 3

RDC-06 Soil Concentrations
Sample Depth Benzene (ug/kg) TVPH (mg/kg)
11 <0.5 <0.5
13 <0.5 <0.5
15 <0.5 <0.5
17 <0.5 <0.5
19 <0.5 <0.5
21 <0.5 <0.5
23 <10 <10
25 <0.5 <0.5
27 <10 <10
29 <0.5 <0.5
31 <10 <10
33 <10 <10
35 <0.5 <0.5
37 <0.5 <0.5
39 <0.5 <0.5
41 <0.5 <0.5
43 <0.5 <0.5
45 <10 <10
47 110 <50
49 160 <50

3-Dimensional Quantitative Model

The soil data collected from the RDC program was loaded into Ejlskov Environmental Site Model
(ESM), a proprietary data visualization and acquisition software developed by Ejlskov A/S, a RPI
Group member. Once entered in the software, a 3-dimensional interpolation of the benzene and
TVPH soil data was produced by using the ESM inverse distance algorithm. From the review of
this data, 2-dimensional figures of the benzene and TVPH maximum soil concentrations, benzene
groundwater isoconcentration map, and cross sections of both contaminant plumes were created
and are included in the Figures attachment.

A total of approximately 8,600 lbs of TVPH and 1,800 lbs of benzene are estimated in the
subsurface based on the ESM 3-d interpolation of the data. This mass total should only be used
viewed as an estimate to possibly generate rough order of magnitude estimate for potential
remediation costs.

Conclusions and Recommendations

As indicated above, the ITRC LNAPL Guidance Document states that TVPH concentrations
indicative of residual LNAPL in the subsurface are between 250 and 500 mg/kg, depending on
the soil type. Based on the data collected during the RDC event and the subsequent interpolation
of the data, the subsurface distribution of residual LNAPL is confined to the area immediately
surrounding and below the former tank pit. In addition to the quantification of residual LNAPL
using the TVPH concentrations, the saturated benzene soil concentrations are also used for
determination of injection locations and depths in order to meet the 2L groundwater standard.
Using the state of Washington three phase partitioning model
(https://www.ezview.wa.gov/Portals/_1987/Documents/Documents/WAC_173-340-
747_SoilDefaultHydrogeologicParameterData_2001.pdf), to be protective of groundwater at 1
ug/L benzene, soil concentrations of benzene must be below 0.411 ug/kg. Considering detection
limits for soil are at 0.5 ug/kg, AST has targeted benzene concentrations with reportable
concentrations in excess of 1 ug/kg or above the detection limit listed at or above 50 ug/kg.
Mr. Ben Ashba
July 28, 2023
Page 4

The vertical distribution of elevated soil concentrations were generally observed with peak
concentrations near the water table, ~35’-37’’ bgs. In addition to the elevated concentrations
observed at the water table near the former tank pit, vertical migration deeper into the saturated
zone is also observed in the data, specifically the elevated benzene concentrations at termination
depths of RDC-06. The transport mechanism allowing the vertical migration of LNAPL appears to
be vertical to subvertical remnant foliation and fracture structure from the parent rock.

Based on the data generated during this qHRSC, AST recommends that a BOS 200+ injection
program be considered for this site, particularly in Area A and Area D, due to the residual LNAPL
concentrations present and deep soil benzene present near MW-02.

Based on the 2L remediation goal of 1 ug/L benzene, and the elevated soil mass present in the
injection area, a BOS 200 plan has been completed that includes supplemental additives to
increase the rate of degradation on the activated carbon surface and prolong the ability of the
facultative microbes to continue the degradation process for years.

BOS 200+ INJECTION DESIGN – SEE ATTACHED FOR DESIGN LOADINGS & FIGURE FOR
LOCATIONS

BOS 200® provides the unique capability (Trap & Treat® process) to utilize two proven and
powerful technologies that rapidly and effectively remediate petroleum hydrocarbon sites:

1) Trapping of the contaminants via activated carbon adsorption.
2) Subsequent treatment via biological degradation within the BOS 200® matrix utilizing both
aerobic and anaerobic microbial processes.

The “Trap” provides the immediate mass reduction and plume control, while the “Treat” provides
the continued long-term remedial degradation using synergistic facultative bacteria. No other
activated carbon product can emplace a biological treatment mechanism on activated carbon for
injection; this intellectual property is protected by RPI patents. AST is designed by RPI as the
product design arm and distributor for the RPI Group.

BOS 200® is a fine-grained, dry material which consists of activated carbon, calcium sulfate,
nitrate, phosphate, and ammonia in a proprietary blend. It is 77% by weight activated carbon and
up to 19% gypsum. The gypsum component itself is 79% by weight sulfate, which translates to
approximately 15% by weight sulfate in BOS 200®. The product is mixed with water and a
facultative blend of aerobic and anaerobic microbes to create a solids suspension. This is now an
ideal environment for biological degradation, where hydrocarbons are adsorbed on to BOS 200®
particles made up of:
• Terminal Electron Acceptors: oxygen, nitrate, ammonia, and sulfate (primary)
• Micro- and Macro-Nutrients - phosphorus and nitrogen
• Aerobic and anaerobic blend of facultative microbes (over 27 species)

On flexibility, with BOS 200® product, the design approach can vary from a treatment objective
where complete and immediate contaminant mass removal from the groundwater is achieved, to
a partial contaminant mass reduction working in conjunction with biological degradation driving
the groundwater cleanup effort, or any combination somewhere in between. The end effect is that
the plume can be controlled in a short period of time and treatment can be extended over a longer
period.

The revised BOS 200® injection design has been prepared for each area using the following
approach/basis:

1. RDC and historical data from soil and groundwater sampling (i.e., analytical results, the
Mr. Ben Ashba
July 28, 2023
Page 5

screened interval of the wells, the soil sampling depth intervals) were used to determine
the vertical and horizontal extent of impacts in each area.

2. Using the same data for each area a contaminant mass loading on a unit basis (lb.
benzene per ft3 of impacted media) was determined for each of the designated areas.

3. The contaminant mass loadings were then used to determine the BOS 200® loadings (lbs.
installed per ft3 of impacted media) necessary to remediate a specific depth interval within
each injection area. This is a balance between the need to have an immediate mass
reduction or to allow the biological process to be the controlling process. This is
specifically discussed for each area below.

4. Based on the recent RDC soil data discovered, a second injection event is
necessary to reach the remediation goal of 1 ug/L benzene and may be needed for
Area A. However, quarterly monitoring of the terminal electron acceptor
consumption will dictate if/when that additional event occurs.

Based on the total saturated soil mass present, a second injection event may be necessary
in Area A to achieve closure levels at this site. Tracking the dissolved phase contaminant
trends (BTEX, TVPH), along with the terminal electron acceptor trend post injection,
specifically sulfate, will determine the necessity and timing of the second injection.

POST INJECTION SAMPLING

Following the injection, AST will collect groundwater samples from all of the monitoring wells
within the injection area prior to demobilizing. AST recommends performance progress
groundwater sampling events at intervals of one week, two weeks, one-month post injection and
quarterly until remediation goals are obtained. AST understands that this will be performed by
others. The performance samples can be sent to Remediation Products, Ince. Laboratory in
Golden, CO for no cost of analyses. The cost of shipment will be the responsibility of the
consultant. The analyses will be consistent with that described previously.

If you have any questions or wish to discuss the information provided herein, please contact me
at [phone] or via email at [e-mail].

Sincerely,
AST Environmental, Inc.

Nathan Thacker
Senior Geologist

Figures

Monitoring Well
Recovery Well
RDC Soil Boring
Legend
AST Environmental
1567 CF Pours Drive
Harrisonburg, Virginia
www.astenv.com
Best Stop 2
10014 Lancaster Highway
Waxhaw, North Carolina
NCDEQ Incident #27776
Monitoring Well
Recovery Well
RDC Soil Boring
Legend
AST Environmental
1567 CF Pours Drive
Harrisonburg, Virginia
www.astenv.com
Best Stop 2
10014 Lancaster Highway
Waxhaw, North Carolina
NCDEQ Incident #27776
Monitoring Well
Recovery Well
RDC Soil Boring
Legend
AST Environmental
1567 CF Pours Drive
Harrisonburg, Virginia
www.astenv.com
Best Stop 2
10014 Lancaster Highway
Waxhaw, North Carolina
NCDEQ Incident #27776
Monitoring Well
Recovery Well
RDC Soil Boring
Legend
AST Environmental
1567 CF Pours Drive
Harrisonburg, Virginia
www.astenv.com
Best Stop 2
10014 Lancaster Highway
Waxhaw, North Carolina
NCDEQ Incident #27776
Monitoring Well
Recovery Well
RDC Soil Boring
Legend
AST Environmental
1567 CF Pours Drive
Harrisonburg, Virginia
www.astenv.com
Best Stop 2
10014 Lancaster Highway
Waxhaw, North Carolina
NCDEQ Incident #27776
AST Environmental
1567 CF Pours Drive
Harrisonburg, Virginia
www.astenv.com
Best Stop 2
10014 Lancaster Highway
Waxhaw, North Carolina
NCDEQ Incident #27776
AST Environmental
1567 CF Pours Drive
Harrisonburg, Virginia
www.astenv.com
Best Stop 2
10014 Lancaster Highway
Waxhaw, North Carolina
NCDEQ Incident #27776

Tables

mg/Kg
Dimethyl SulfideMTBE1,2-DichloroethaneBenzeneTolueneEthylbenzenem/p-Xyleneo-XyleneTotal Xylene1,2,4-TrimethylbenzeneNaphthaleneTVPH1,2-Dichloroethane-d4d8-Toluenep-BromofluorobenzeneRDC-01 5/17/2023 11 43 <10 510 <10 <10 <10 <10 <10 <10 0 14 <10 <10 98 102 89
RDC-01 5/17/2023 13 6.3 <10 89 <10 <10 <10 <10 <10 <10 0 <10 <10 <10 98 100 91
RDC-01 5/17/2023 15 25.4 <10 260 <10 <10 <10 <10 <10 <10 0 <10 19 <10 99 99 95
RDC-01 5/17/2023 17 5 <10 70 <10 <10 <10 <10 <10 <10 0 <10 43 <10 99 102 94
RDC-01 5/17/2023 19 36.1 <10 350 <10 <10 <10 <10 <10 <10 0 12 65 <10 100 100 93
RDC-01 5/17/2023 21 83.2 <10 970 <10 <10 <10 <10 <10 <10 0 15 71 <10 94 102 80
RDC-01 5/17/2023 23 9.6 <10 220 <10 <10 <10 <10 <10 <10 0 15 64 <10 99 100 93
RDC-01 5/17/2023 25 17.2 <10 160 <10 <10 <10 <10 <10 <10 0 11 71 <10 96 99 96
RDC-01 5/17/2023 27 82.9 <10 <10 <10 <10 <10 <10 <10 <10 0 <10 13 <10 95 98 100
RDC-01 5/17/2023 29 1487 <250 1300 <250 <250 7400 7700 40500 21800 62300 62700 8600 700 91 100 99
RDC-01 5/17/2023 31 1365 <250 650 <250 <250 1600 4600 27000 16200 43200 54400 8800 590 90 101 99
RDC-01 5/17/2023 33 2000 <500 2000 <500 <500 49000 30100 152000 75000 227000 149000 21100 1900 90 101 100
RDC-01 5/17/2023 35 1478 <250 4300 <250 750 54900 26600 108000 49600 157600 79800 10300 1300 93 99 102
RDC-01 5/17/2023 37 747 <250 4100 <250 5000 85900 26900 97800 42100 139900 64000 7600 1300 94 100 101
RDC-01 5/17/2023 39 302 <50 2800 <50 1400 9500 1500 5300 2500 7800 2500 270 68 100 101 98
RDC-01 5/17/2023 41 125 <50 260 <50 130 2400 430 1400 830 2230 440 92 <50 97 101 98
RDC-01 5/17/2023 43 71 <10 69 <10 33 550 190 920 520 1440 340 47 10 99 100 94
RDC-01 5/17/2023 45 35 <10 35 <10 26 14 72 24 14 38 28 38 <10 99 102 98
RDC-01 5/17/2023 47 25 <10 <10 <10 <10 <10 <10 <10 <10 0 9.6 25 <10 97 101 94
RDC-01 5/17/2023 49 12 <0.5 21 <0.5 <0.5 3.4 0.9 3.8 1.9 5.7 2.3 1 <0.5 82 98 96
% Surrogate Recovery
Facility name: Catlin - Best Stop #2
Table 1
Soil Analytical Results
Chemical of concern (ug/kg)
Sample
location
Sample
date
Sample
depth
(ft)
PID or
OVD
reading
(ppm)
mg/Kg
Dimethyl SulfideMTBE1,2-DichloroethaneBenzeneTolueneEthylbenzenem/p-Xyleneo-XyleneTotal Xylene1,2,4-TrimethylbenzeneNaphthaleneTVPH1,2-Dichloroethane-d4d8-Toluenep-Bromofluorobenzene% Surrogate Recovery
Facility name: Catlin - Best Stop #2
Table 1
Soil Analytical Results
Chemical of concern (ug/kg)
Sample
location
Sample
date
Sample
depth
(ft)
PID or
OVD
reading
(ppm)
RDC-02 5/17/2023 11 24.5 <10 34 <10 <10 <10 <10 <10 <10 0 22 41 <10 75 93 89
RDC-02 5/17/2023 13 23.7 <0.5 100 <0.5 1 1.9 0.6 2.3 1 3.3 1.8 17 <0.5 104 96 82
RDC-02 5/17/2023 15 67.6 <0.5 160 <0.5 <0.5 1.2 0.6 3.1 1.4 4.5 5.3 76 <0.5 103 97 80
RDC-02 5/17/2023 17 55.5 <10 120 <10 <10 <10 <10 <10 <10 0 13 110 <10 76 92 87
RDC-02 5/17/2023 19 44.4 <0.5 670 <0.5 <0.5 2.7 0.9 7.5 12 19.5 89 270 3.4 99 97 83
RDC-02 5/17/2023 21 50.8 <0.5 360 <0.5 <0.5 1.1 <0.5 2.6 3.2 5.8 29 190 2.1 90 95 85
RDC-02 5/17/2023 23 15.2 <0.5 300 <0.5 <0.5 0.9 <0.5 1.2 0.7 1.9 2.9 110 0.7 83 94 84
RDC-02 5/17/2023 25 19.3 <0.5 78 <0.5 <0.5 2.2 <0.5 1.8 0.7 2.5 1.6 46 <0.5 82 92 81
RDC-02 5/17/2023 27 69 <10 390 <10 <10 <10 <10 <10 <10 0 15 78 <10 77 93 88
RDC-02 5/17/2023 29 185 <50 1000 <50 56 <50 86 99 <50 99 68 120 <50 82 93 85
RDC-02 5/17/2023 31 692 <50 250 87 150 <50 210 520 310 830 3900 730 98 82 93 87
RDC-02 5/17/2023 33 401 <10 140 <10 <10 <10 <10 18 24 42 690 250 27 79 93 88
RDC-02 5/17/2023 35 441 <50 70 86 250 1300 2300 10300 3500 13800 36000 460 1100 78 93 89
RDC-02 5/17/2023 37 35 <0.5 3.3 <0.5 2.3 9.2 21 110 50 160 470 11 7.8 83 97 88
RDC-02 5/17/2023 39 23.6 <0.5 0.9 <0.5 <0.5 1.3 1.4 9.9 3.9 13.8 130 3.6 2.1 82 92 88
RDC-02 5/17/2023 41 13.7 <0.5 0.9 <0.5 <0.5 0.8 <0.5 1.4 0.6 2 17 1.1 <0.5 100 93 84
RDC-02 5/17/2023 43 10.9 <0.5 13 <0.5 <0.5 1.9 <0.5 1.2 0.7 1.9 1.1 <0.5 <0.5 95 92 82
mg/Kg
Dimethyl SulfideMTBE1,2-DichloroethaneBenzeneTolueneEthylbenzenem/p-Xyleneo-XyleneTotal Xylene1,2,4-TrimethylbenzeneNaphthaleneTVPH1,2-Dichloroethane-d4d8-Toluenep-Bromofluorobenzene% Surrogate Recovery
Facility name: Catlin - Best Stop #2
Table 1
Soil Analytical Results
Chemical of concern (ug/kg)
Sample
location
Sample
date
Sample
depth
(ft)
PID or
OVD
reading
(ppm)
RDC-03 5/17/2023 11 2.1 <0.5 11 <0.5 <0.5 1.4 <0.5 1.4 0.8 2.2 1.5 <0.5 <0.5 87 91 75
RDC-03 5/17/2023 13 4.2 <0.5 3.5 <0.5 <0.5 0.6 <0.5 0.7 <0.5 0.7 0.9 <0.5 <0.5 106 92 81
RDC-03 5/17/2023 15 19.4 <0.5 15 <0.5 <0.5 0.9 <0.5 1.4 0.7 2.1 2.3 8.5 <0.5 105 95 84
RDC-03 5/17/2023 17 7.1 <0.5 20 <0.5 <0.5 0.9 <0.5 0.9 0.5 1.4 2.2 17 0.7 102 95 86
RDC-03 5/17/2023 19 25.4 <0.5 160 <0.5 0.8 7.1 1.3 10 15 25 58 76 2.1 94 95 88
RDC-03 5/17/2023 21 16.3 <0.5 220 <0.5 4.6 44 9.2 65 72 137 220 140 5 83 93 88
RDC-03 5/17/2023 23 34 <0.5 73 <0.5 <0.5 2 <0.5 2.2 1.3 3.5 4.3 61 0.9 84 91 85
RDC-03 5/17/2023 25 7.3 <0.5 3.9 <0.5 <0.5 1 <0.5 0.9 <0.5 0.9 1 10 <0.5 83 91 84
RDC-03 5/17/2023 27 17.1 <0.5 66 <0.5 <0.5 1.4 <0.5 1.4 0.8 2.2 2.3 75 1 86 92 85
RDC-03 5/17/2023 29 28.1 <10 37 <10 <10 <10 <10 14 <10 14 24 18 <10 105 102 90
RDC-03 5/17/2023 31 163.7 <50 150 <50 110 73 930 5000 3200 8200 26000 3900 330 100 102 99
RDC-03 5/17/2023 33 1330 <50 200 <50 170 10700 18300 68200 33900 102100 63700 11600 1400 99 102 102
RDC-03 5/17/2023 35 233.4 <50 580 <50 1100 18700 10600 38400 16200 54600 36500 4000 650 93 100 99
RDC-03 5/17/2023 37 122.9 <10 530 <10 770 10300 5700 14700 7300 22000 17200 1300 370 94 105 96
RDC-03 5/17/2023 39 100 <50 310 <50 690 3000 840 2700 1100 3800 3900 440 70 98 100 97
RDC-03 5/17/2023 41 31.2 <0.5 83 <0.5 220 140 160 460 150 610 470 36 7.7 81 95 85
RDC-03 5/17/2023 43 24.2 <10 26 <10 72 28 120 450 160 610 1200 54 16 99 100 93
RDC-03 5/17/2023 45 NC <0.5 7 <0.5 35 71 89 290 120 410 410 12 5.3 81 93 85
RDC-03 5/17/2023 47 NC <0.5 2.9 <0.5 5.1 11 20 74 26 100 130 3.9 2.5 83 93 87
RDC-03 5/17/2023 49 NC <0.5 1.5 <0.5 9.5 2.1 22 84 26 110 170 2.2 3.3 83 94 88
mg/Kg
Dimethyl SulfideMTBE1,2-DichloroethaneBenzeneTolueneEthylbenzenem/p-Xyleneo-XyleneTotal Xylene1,2,4-TrimethylbenzeneNaphthaleneTVPH1,2-Dichloroethane-d4d8-Toluenep-Bromofluorobenzene% Surrogate Recovery
Facility name: Catlin - Best Stop #2
Table 1
Soil Analytical Results
Chemical of concern (ug/kg)
Sample
location
Sample
date
Sample
depth
(ft)
PID or
OVD
reading
(ppm)
RDC-04 5/18/2023 11 0 <0.5 0.6 <0.5 <0.5 0.8 <0.5 1.4 0.6 2 1.9 0.5 <0.5 82 91 83
RDC-04 5/18/2023 13 0 <0.5 <0.5 <0.5 <0.5 0.7 <0.5 0.9 <0.5 0.9 1.4 0.6 <0.5 85 91 83
RDC-04 5/18/2023 15 0 <0.5 <0.5 <0.5 <0.5 0.9 <0.5 1 0.6 1.6 1.1 <0.5 <0.5 92 93 81
RDC-04 5/18/2023 17 0 <0.5 <0.5 <0.5 <0.5 1.7 <0.5 1.4 0.8 2.2 1.2 <0.5 <0.5 97 92 81
RDC-04 5/18/2023 19 0 <0.5 <0.5 <0.5 <0.5 2.3 <0.5 0.8 1.7 2.5 0.9 <0.5 <0.5 90 88 70
RDC-04 5/18/2023 21 0 <0.5 <0.5 <0.5 <0.5 0.7 <0.5 0.7 <0.5 0.7 <0.5 <0.5 <0.5 102 95 75
RDC-04 5/18/2023 23 0 <0.5 <0.5 <0.5 <0.5 1.3 <0.5 1 0.5 1.5 0.8 <0.5 <0.5 116 95 78
RDC-04 5/18/2023 25 0 <0.5 0.5 <0.5 <0.5 1.8 <0.5 1.7 0.9 2.6 2.2 1 0.7 122 98 87
RDC-04 5/18/2023 27 0 <0.5 <0.5 <0.5 <0.5 1.1 0.7 1.7 5.8 7.5 1.8 <0.5 12 102 100 112
RDC-04 5/18/2023 29 0 <0.5 <0.5 <0.5 <0.5 2.3 2 3.3 12 15.3 19 4.2 16 85 95 92
RDC-04 5/18/2023 31 0 <0.5 <0.5 <0.5 <0.5 <0.5 6.4 13 43 56 210 17 15 78 92 88
RDC-04 5/18/2023 33 2.6 <0.5 <0.5 <0.5 <0.5 1 19 47 110 157 630 89 37 76 89 96
RDC-04 5/18/2023 35 0 <0.5 <0.5 <0.5 1.9 0.9 3.8 38 77 115 250 33 4.6 72 91 84
RDC-04 5/18/2023 37 0 <0.5 <0.5 <0.5 5.6 <0.5 <0.5 50 92 142 120 40 2 75 91 85
mg/Kg
Dimethyl SulfideMTBE1,2-DichloroethaneBenzeneTolueneEthylbenzenem/p-Xyleneo-XyleneTotal Xylene1,2,4-TrimethylbenzeneNaphthaleneTVPH1,2-Dichloroethane-d4d8-Toluenep-Bromofluorobenzene% Surrogate Recovery
Facility name: Catlin - Best Stop #2
Table 1
Soil Analytical Results
Chemical of concern (ug/kg)
Sample
location
Sample
date
Sample
depth
(ft)
PID or
OVD
reading
(ppm)
RDC-05 5/18/2023 11 0 <0.5 <0.5 <0.5 <0.5 0.8 <0.5 1.4 0.5 1.9 1.4 <0.5 <0.5 77 98 99
RDC-05 5/18/2023 13 0 <0.5 <0.5 <0.5 <0.5 1.1 <0.5 1.8 0.9 2.7 2.1 0.5 <0.5 80 96 93
RDC-05 5/18/2023 15 0 <0.5 <0.5 <0.5 <0.5 0.8 <0.5 1.6 0.8 2.4 1.8 <0.5 <0.5 67 94 94
RDC-05 5/18/2023 17 0 <0.5 <0.5 <0.5 <0.5 1.7 0.6 3 1.6 4.6 3.4 <0.5 <0.5 71 96 92
RDC-05 5/18/2023 19 0 <0.5 <0.5 <0.5 <0.5 0.7 <0.5 1.4 0.5 1.9 1.5 <0.5 <0.5 69 94 96
RDC-05 5/18/2023 21 0 <0.5 <0.5 <0.5 <0.5 1.3 <0.5 1.7 0.8 2.5 1.7 <0.5 <0.5 65 98 95
RDC-05 5/18/2023 23 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0.6 <0.5 0.6 0.7 <0.5 <0.5 95 98 96
RDC-05 5/18/2023 25 0 <0.5 <0.5 <0.5 <0.5 1.4 <0.5 2.5 1 3.5 2.1 <0.5 <0.5 62 96 92
RDC-05 5/18/2023 27 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0 0.5 <0.5 <0.5 100 100 96
RDC-05 5/18/2023 29 0 <10 <10 <10 <10 8.8 <10 24 13 37 140 24 8.4 100 101 92
RDC-05 5/18/2023 31 0 <0.5 <0.5 <0.5 <0.5 0.6 <0.5 0.9 0.5 1.4 1.3 <0.5 <0.5 80 98 99
RDC-05 5/18/2023 33 0 <0.5 <0.5 <0.5 <0.5 0.5 <0.5 0.9 <0.5 0.9 1.4 <0.5 <0.5 73 97 91
RDC-05 5/18/2023 35 0 <0.5 <0.5 <0.5 <0.5 1.2 <0.5 2 1 3 2.1 <0.5 <0.5 80 97 94
RDC-05 5/18/2023 37 0 <0.5 <0.5 <0.5 <0.5 2.8 1 4.4 2 6.4 3.2 <0.5 <0.5 83 95 93
RDC-05 5/18/2023 39 0 <0.5 <0.5 <0.5 <0.5 2.1 0.7 3 1.4 4.4 2 <0.5 <0.5 82 97 94
RDC-05 5/18/2023 41 0 <0.5 <0.5 <0.5 <0.5 2.1 0.7 2.7 1.4 4.1 1.9 <0.5 <0.5 88 97 96
RDC-05 5/18/2023 43 0 <0.5 <0.5 <0.5 <0.5 1 0.5 1.1 0.6 1.7 0.9 <0.5 <0.5 97 100 98
RDC-05 5/18/2023 45 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0 <0.5 <0.5 <0.5 101 93 85
RDC-05 5/18/2023 47 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0 <0.5 <0.5 <0.5 98 99 93
RDC-05 5/18/2023 49 0 <0.5 3.8 <0.5 <0.5 1.3 <0.5 1.6 0.7 2.3 1.2 <0.5 <0.5 88 99 93
mg/Kg
Dimethyl SulfideMTBE1,2-DichloroethaneBenzeneTolueneEthylbenzenem/p-Xyleneo-XyleneTotal Xylene1,2,4-TrimethylbenzeneNaphthaleneTVPH1,2-Dichloroethane-d4d8-Toluenep-Bromofluorobenzene% Surrogate Recovery
Facility name: Catlin - Best Stop #2
Table 1
Soil Analytical Results
Chemical of concern (ug/kg)
Sample
location
Sample
date
Sample
depth
(ft)
PID or
OVD
reading
(ppm)
RDC-06 5/18/2023 11 0 <0.5 <0.5 <0.5 <0.5 1.2 0.5 2.4 1.1 3.5 2.6 <0.5 <0.5 75 99 90
RDC-06 5/18/2023 13 0 <0.5 <0.5 <0.5 <0.5 1 0.5 1.8 0.9 2.7 1.8 <0.5 <0.5 76 95 92
RDC-06 5/18/2023 15 0 <0.5 <0.5 <0.5 <0.5 1.3 0.6 2.5 1.1 3.6 2.7 <0.5 <0.5 67 96 93
RDC-06 5/18/2023 17 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 1.1 0.6 1.7 2 <0.5 <0.5 68 97 90
RDC-06 5/18/2023 19 0 <0.5 <0.5 <0.5 <0.5 0.6 <0.5 1.1 0.6 1.7 1.9 <0.5 <0.5 75 95 91
RDC-06 5/18/2023 21 0 <0.5 <0.5 <0.5 <0.5 0.7 <0.5 2.2 0.8 3 5 <0.5 <0.5 64 96 91
RDC-06 5/18/2023 23 0 <10 <10 <10 <10 <10 <10 15 <10 15 59 13 <10 105 97 95
RDC-06 5/18/2023 25 0 <0.5 <0.5 <0.5 <0.5 0.8 <0.5 1.4 0.7 2.1 1.9 <0.5 <0.5 72 97 88
RDC-06 5/18/2023 27 0 <10 <10 <10 <10 <10 <10 11 <10 11 33 <10 <10 101 102 95
RDC-06 5/18/2023 29 0 <0.5 <0.5 <0.5 <0.5 1.2 <0.5 1.9 0.9 2.8 2 <0.5 <0.5 90 95 91
RDC-06 5/18/2023 31 0 <10 <10 <10 <10 <10 <10 <10 <10 0 22 <10 <10 99 99 94
RDC-06 5/18/2023 33 0 <10 <10 <10 <10 <10 <10 10 <10 10 22 <10 <10 100 102 94
RDC-06 5/18/2023 35 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0.8 <0.5 0.8 0.7 <0.5 <0.5 96 98 94
RDC-06 5/18/2023 37 0 <0.5 <0.5 <0.5 <0.5 1.8 0.6 2.8 1.3 4.1 2.5 0.5 <0.5 83 96 95
RDC-06 5/18/2023 39 0 <0.5 <0.5 <0.5 <0.5 0.9 <0.5 1.2 0.7 1.9 1.1 <0.5 <0.5 95 96 94
RDC-06 5/18/2023 41 0 <0.5 <0.5 <0.5 <0.5 1.3 0.6 2.1 0.8 2.9 2.1 <0.5 <0.5 90 96 95
RDC-06 5/18/2023 43 0 <0.5 <0.5 <0.5 <0.5 1.5 <0.5 2 0.9 2.9 1.3 <0.5 <0.5 92 98 94
RDC-06 5/18/2023 45 0 <10 28 <10 <10 <10 <10 <10 <10 0 18 <10 <10 100 101 95
RDC-06 5/18/2023 47 0 <50 160 <50 110 270 360 930 390 1320 410 <50 <50 96 99 94
RDC-06 5/18/2023 49 0 <50 <50 <50 160 <50 230 290 61 351 150 <50 <50 98 101 97
mg/Kg
Dimethyl SulfideMTBE1,2-DichloroethaneBenzeneTolueneEthylbenzenem/p-Xyleneo-XyleneTotal Xylene1,2,4-TrimethylbenzeneNaphthaleneTVPH1,2-Dichloroethane-d4d8-Toluenep-Bromofluorobenzene% Surrogate Recovery
Facility name: Catlin - Best Stop #2
Table 1
Soil Analytical Results
Chemical of concern (ug/kg)
Sample
location
Sample
date
Sample
depth
(ft)
PID or
OVD
reading
(ppm)
RDC-07 5/18/2023 11 0 <0.5 <0.5 <0.5 <0.5 0.7 0.8 1.9 0.5 2.4 1.8 <0.5 <0.5 76 97 90
RDC-07 5/18/2023 13 0 <10 <10 <10 <10 <10 <10 <10 <10 0 13 <10 <10 101 100 93
RDC-07 5/18/2023 15 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0.9 <0.5 0.9 1.3 <0.5 <0.5 79 96 91
RDC-07 5/18/2023 17 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0 <0.5 <0.5 <0.5 108 96 92
RDC-07 5/18/2023 19 0 <0.5 <0.5 <0.5 <0.5 0.6 <0.5 1.2 0.5 1.7 1.5 <0.5 <0.5 76 97 89
RDC-07 5/18/2023 25 0 <0.5 <0.5 <0.5 2.5 10 1.4 6.7 2.3 9 3 <0.5 <0.5 80 97 92
RDC-07 5/18/2023 27 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0.6 <0.5 0.6 0.7 <0.5 <0.5 80 97 92
RDC-07 5/18/2023 29 0 <0.5 <0.5 <0.5 <0.5 0.5 <0.5 1.9 0.7 2.6 2.2 <0.5 <0.5 97 97 94
RDC-07 5/18/2023 31 0 <10 <10 <10 <10 <10 <10 <10 <10 0 15 <10 <10 100 101 94
RDC-07 5/18/2023 33 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 0.7 <0.5 0.7 1 <0.5 <0.5 106 94 89
RDC-07 5/18/2023 35 0 <0.5 <0.5 <0.5 <0.5 1 0.5 5.7 1.4 7.1 2 <0.5 <0.5 79 97 94
RDC-07 5/18/2023 37 0 <0.5 <0.5 <0.5 <0.5 0.6 <0.5 1 0.5 1.5 1.2 <0.5 <0.5 83 98 92
RDC-07 5/18/2023 39 0 <0.5 <0.5 <0.5 <0.5 1.1 0.6 2.5 0.6 3.1 2.5 <0.5 <0.5 85 98 92
RDC-07 5/18/2023 41 0 <0.5 <0.5 <0.5 <0.5 2.3 1.2 5.7 2.6 8.3 4.2 <0.5 <0.5 89 97 88
RDC-07 5/18/2023 43 0 <0.5 <0.5 <0.5 <0.5 1.1 0.5 2.3 0.9 3.2 2.1 <0.5 <0.5 103 100 91
RDC-07 5/18/2023 45 0 <0.5 <0.5 <0.5 <0.5 1.7 0.6 2.6 1.3 3.9 2.1 <0.5 <0.5 80 98 94
RDC-07 5/18/2023 47 0 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 1 <0.5 1 1 <0.5 <0.5 91 97 95
RDC-07 5/18/2023 49 0 <0.5 <0.5 <0.5 0.6 <0.5 1 <0.5 1 0.8 <0.5 <0.5 99 98 97
mg/L
Dimethyl SulfideMTBE1,2-DichloroethaneBenzeneTolueneEthylbenzenem/p-Xyleneo-XyleneTotal Xylene1,2,4-TrimethylbenzeneNaphthaleneTVPH1,2-Dichloroethane-d4d8-Toluenep-BromofluorobenzeneMW-01 5/18/2023 25-45 <10 28300 <10 4200 24900 2400 10100 6000 16100 3000 540 120 84 95 88
MW-02 5/18/2023 25-45 <5 810 <5 50 1700 1100 3300 1700 5000 1400 230 33 85 94 86
MW-04 5/18/2023 30-50 <0.5 <0.5 <0.5 0.8 1.6 0.7 11 15 26 13 2.8 0.5 89 93 88
MW-05 5/18/2023 35-45 <5 660 <5 2000 5100 1700 5100 2300 7400 3100 400 63 84 94 87
MW-07R 5/18/2023 40-50 <0.5 59 <0.5 0.8 2.2 0.5 2.2 1 3.2 1.9 0.5 <0.5 89 93 86
OW-04N 5/18/2023 30-40 <50 8800 <50 1900 9300 2300 9400 4100 13500 4100 310 110 89 94 86
RW-01 5/18/2023 40-50 <50 4100 <50 2300 14900 1800 7700 3900 11600 3300 340 100 94 95 89
RDC-04 5/18/2023 32-37 <0.5 <0.5 <0.5 19 2.2 1.4 160 260 420 360 140 4.8 91 94 85
Facility name: Catlin - Best Stop #2
Table 2
Water Analytical Results
Sample
location Sample date
Sample
Depth
% Surrogate RecoveryChemical of Concern (ug/L)

Attachment B
Soil Boring Logs

52
48
44
40
36
32
28
24
20
16
12
8
4
0
100
100
100
100
100
100
100
100
RDC-01 (11')
RDC-01 (13')
RDC-01 (15')
RDC-01 (17')
RDC-01 (19')
RDC-01 (21')
RDC-01 (23')
RDC-01 (25')
RDC-01 (27')
RDC-01 (29')
RDC-01 (31')
RDC-01 (33')
RDC-01 (35')
RDC-01 (37')
RDC-01 (39')
RDC-01 (41')
RDC-01 (43')
RDC-01 (45')
RDC-01 (47')
RDC-01 (49')
<10
<10
<10
<10
<10
<10
<10
<10
<10
<250
<250
<500
750
5000
1400
130
33
26
<10
<0.5
ML
CL
ML
CL
Geological logging not performed
Red silty clay, dry, slight petroleum odor, some
fine tan sand throughout
Red clayey silt, dry, slight odor, fine tan sand in
horizontal bands from 13-15'
Red silty clay, dry, slight petroleum odor, sand in
horizontal bands
White/tan clayey silt, dry, some sand, slight odor,
red banding throughout
White/tan clayey silt, some fine sand, dry
White/tan clayey silt, some fine sand, moist, moderate odor
Tan/white clayey silt, moist, some fine sands,
moderate odor, sand lense 32.5-33', dark brown
mineralization 34-35'
Tan/white clayey silt, moist, some fine sands,
moderate odor, dark brown mineralization
throughout, saturated 36-37',
Silt, white, wet, slight odor
Tan clayey silt, saturated, some sand, coarse
sand lense at 44'
Saturated tan clayey silt, some sand
Moist tan sandy silt, slight odor throughout
Moist tan sandy silt, coarse sand present, slight odor throughout
Boring Terminated 50'
<10
<10
<10
<10
<10
<10
<10
<10
<10
700
590
1900
1300
1300
68
<50
10
<10
<10
<0.5
DESCRIPTION
NAME (USCS): color, sorting, plasticity,
moisture, sorting, grain size, packing
Catlin - Best Stop #2
GEX
Direct Push
Geoprobe 7822
3.25 Dual Tube
Nathan Mau
Nathan Thacker
RDC-01
REC-OVERY(%)LAB I.D.DEPTH(feet)WELL CONSTRUCTION
DETAILS AND/OR
DRILLING REMARKS
Benzene (soil)(ppb)
PROJECT MANAGER:
PROJECT:
BORING IDENTIFICATION:
DRILLING CONTRACTOR:
DRILLING METHOD:
SAMPLING METHOD:
DRILLING EQUIPMENT:
REG. NO.
LOGGED BY:
DEPTH TO WATER:CASING:
TOTAL DEPTH:SCREEN INTERVAL:
DATE FINISHED:
DATE STARTED:
NORTHING:
EASTING:
ELEVATION:
May 17, 2023
May 17, 2023
50'
TVPH (soil)
(ppm)
AST Environmental Inc.Project No.Page 1 of 15152388
44
40
36
32
28
24
20
16
12
8
4
0
100
100
100
100
100
100
100
RDC-02 (11')
RDC-02 (13')
RDC-02 (15')
RDC-02 (17')
RDC-02 (19')
RDC-02 (21')
RDC-02 (23')
RDC-02 (25')
RDC-02 (27')
RDC-02 (29')
RDC-02 (31')
RDC-02 (33')
RDC-02 (35')
RDC-02 (37')
RDC-02 (39')
RDC-02 (41')
RDC-02 (43')
<10
1
<0.5
<10
<0.5
<0.5
<0.5
<0.5
<10
56
150
<10
250
2.3
<0.5
<0.5
<0.5
ML
CL
Geological logging not performed
Red silty clay, dry, hard, slight odor, some fine sand
Dry crumbly gray/red silty clay, slight odor
Dry crumbly gray/red silty clay, moderate odor
17-20'
Dry gray/tan clayey silt, slight odor, red mottling
throughout
Tan clayey silt, moderate odor, horizontal and vertical black streaking throughout, some sand
Tan clayey silt, moderate odor, horizontal and
vertical black streaking throughout, some sand,
moist
Black streaked gray/brown clayey silt, slight odor, wet
Black streaked gray/brown clayey silt, slight odor,
dry
Brown clayey silt, moist
Brown clayey silt, saturated
Brown clayey silt, dry
Refusal at 43'
<10
<0.5
<0.5
<10
3.4
2.1
0.7
<0.5
<10
<50
98
27
1100
7.8
2.1
<0.5
<0.5
DESCRIPTION
NAME (USCS): color, sorting, plasticity,
moisture, sorting, grain size, packing
Catlin - Best Stop #2
GEX
Direct Push
Geoprobe 7822
3.25 Dual Tube
Nathan Mau
Nathan Thacker
RDC-02
REC-OVERY(%)LAB I.D.DEPTH(feet)WELL CONSTRUCTION
DETAILS AND/OR
DRILLING REMARKS
Benzene (soil)(ppb)
PROJECT MANAGER:
PROJECT:
BORING IDENTIFICATION:
DRILLING CONTRACTOR:
DRILLING METHOD:
SAMPLING METHOD:
DRILLING EQUIPMENT:
REG. NO.
LOGGED BY:
DEPTH TO WATER:CASING:
TOTAL DEPTH:SCREEN INTERVAL:
DATE FINISHED:
DATE STARTED:
NORTHING:
EASTING:
ELEVATION:
May 17, 2023
May 17, 2023
43'
TVPH (soil)
(ppm)
AST Environmental Inc.Project No.Page 1 of 15152388
52
48
44
40
36
32
28
24
20
16
12
8
4
0
100
100
100
100
100
100
100
100
RDC-03 (11')
RDC-03 (13')
RDC-03 (15')
RDC-03 (17')
RDC-03 (19')
RDC-03 (21')
RDC-03 (23')
RDC-03 (25')
RDC-03 (27')
RDC-03 (29')
RDC-03 (31')
RDC-03 (33')
RDC-03 (35')
RDC-03 (37')
RDC-03 (39')
RDC-03 (41')
RDC-03 (43')
RDC-03 (45')
RDC-03 (47')
RDC-03 (49')
<0.5
<0.5
<0.5
<0.5
0.8
4.6
<0.5
<0.5
<0.5
<10
110
170
1100
770
690
220
72
35
5.1
9.5
CL
ML
CL
ML
CL
Geological logging not performed
Dry, hard, red silty clay, small gravel ~12-12.5', crumbly from 14'-15'
Dry, crumbly red silty clay with gray mottling, slight odor
Dry gray/tan clayey silt, moderate odor, red mottling, some fine sand
Tan/gray silty clay, some sand, dry dark banding
28'-30'
Gray/brown sandy silt, moist, moderate odor, dark
brown/black banding 33'-35'
Brown sandy silt, wet, black streaking throughout,
moderate odorBrown sandy silt, saturated, black streaking throughout, moderate odorBrown sandy silt, moist, black streaking throughout, moderate odorWhite/brown sandy silt, wet, slight odor, black
banding 41'
Gray/brown sandy silt, moist, black banding 44'
Gray/brown sandy clay, saturated, slight odor
Gray/brown sandy clay, moist, some fine gravel,
black banding throughout
Boring Terminated 50'
<0.5
<0.5
<0.5
0.7
2.1
5
0.9
<0.5
1
<10
330
1400
650
370
70
7.7
16
5.3
2.5
3.3
DESCRIPTION
NAME (USCS): color, sorting, plasticity,
moisture, sorting, grain size, packing
Catlin - Best Stop #2
GEX
Direct Push
Geoprobe 7822
3.25 Dual Tube
Nathan Mau
Nathan Thacker
RDC-03
REC-OVERY(%)LAB I.D.DEPTH(feet)WELL CONSTRUCTION
DETAILS AND/OR
DRILLING REMARKS
Benzene (soil)(ppb)
PROJECT MANAGER:
PROJECT:
BORING IDENTIFICATION:
DRILLING CONTRACTOR:
DRILLING METHOD:
SAMPLING METHOD:
DRILLING EQUIPMENT:
REG. NO.
LOGGED BY:
DEPTH TO WATER:CASING:
TOTAL DEPTH:SCREEN INTERVAL:
DATE FINISHED:
DATE STARTED:
NORTHING:
EASTING:
ELEVATION:
May 17, 2023
May 17, 2023
50'
TVPH (soil)
(ppm)
AST Environmental Inc.Project No.Page 1 of 15152388
40
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
100
100
100
100
100
100
RDC-04 (11')
RDC-04 (13')
RDC-04 (15')
RDC-04 (17')
RDC-04 (19')
RDC-04 (21')
RDC-04 (23')
RDC-04 (25')
RDC-04 (27')
RDC-04 (29')
RDC-04 (31')
RDC-04 (33')
RDC-04 (35')
RDC-04 (37')
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
1.9
5.6
CL
Geological logging not performed
Stiff, dry red silty clay, some tan mottling
Stiff, dry red silty clay, some tan mottling, more
tan silt present 17'-20'
Red/brown silty clay, moist, medium firm, some
white mottling, black banding at 22' and 24'
Brown, dry sandy clay
Red/brown sandy clay with white mottling, moist, black banding both horizontal and vertical throughout, slight odor from 28'-30'
Red/brown sandy clay with white mottling, moist, black banding both horizontal and vertical throughout, slight odor
Sandy brown clay, wet, moderate odor, more
gray/white clay present 33'-35'
Tan/red silty clay, wet
Tan/red silty clay, dry, some coarse sand/gravel at
38'
Refusal at 38'
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
0.7
12
16
15
37
4.6
2
DESCRIPTION
NAME (USCS): color, sorting, plasticity,
moisture, sorting, grain size, packing
Catlin - Best Stop #2
GEX
Direct Push
Geoprobe 7822
3.25 Dual Tube
Nathan Mau
Nathan Thacker
RDC-04
REC-OVERY(%)LAB I.D.DEPTH(feet)WELL CONSTRUCTION
DETAILS AND/OR
DRILLING REMARKS
Benzene (soil)(ppb)
PROJECT MANAGER:
PROJECT:
BORING IDENTIFICATION:
DRILLING CONTRACTOR:
DRILLING METHOD:
SAMPLING METHOD:
DRILLING EQUIPMENT:
REG. NO.
LOGGED BY:
DEPTH TO WATER:CASING:
TOTAL DEPTH:SCREEN INTERVAL:
DATE FINISHED:
DATE STARTED:
NORTHING:
EASTING:
ELEVATION:
May 18, 2023
May 18, 2023
38'32'-37'
TVPH (soil)
(ppm)
AST Environmental Inc.Project No.Page 1 of 15152388
52
48
44
40
36
32
28
24
20
16
12
8
4
0
100
100
100
90
100
100
100
100
RDC-05 (11')
RDC-05 (13')
RDC-05 (15')
RDC-05 (17')
RDC-05 (19')
RDC-05 (21')
RDC-05 (23')
RDC-05 (25')
RDC-05 (27')
RDC-05 (29')
RDC-05 (31')
RDC-05 (33')
RDC-05 (35')
RDC-05 (37')
RDC-05 (39')
RDC-05 (41')
RDC-05 (43')
RDC-05 (45')
RDC-05 (47')
RDC-05 (49')
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<10
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
CL
SM
CL
Geological logging not performed
Red/tan clay, dry, sandy, some coarse sand from 12'-13'
Red/tan clay, dry, sandy, some coarse sand
White/tan sandy clay, dry, red mottling
Red sandy clay, dry, ~4" band of white sandy clay at 19'
Red/tan sandy clay, dry with white mottling
White silty sand, dry
gravel 27'-29', dry
Red sandy clay, some gravel ~34', moist from
32'-35', brown mottling throughout
Red sandy clay, moist, brown mottling throughout, sand/gravel lenses at 36.5', 38', 39', with dark mineralization
Tan sandy clay, moist, with vertical black banding
Red/gray sandy clay, moist, ~2" small gravel lense
at 41', dark mineralization
Red/brown sandy clay, wet, some small gravel
White/brown sandy clay, moist, more gravel, black
banding throughout
Boring Terminated 50'
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
8.4
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
DESCRIPTION
NAME (USCS): color, sorting, plasticity,
moisture, sorting, grain size, packing
Catlin - Best Stop #2
GEX
Direct Push
Geoprobe 7822
3.25 Dual Tube
Nathan Mau
Nathan Thacker
RDC-05
REC-OVERY(%)LAB I.D.DEPTH(feet)WELL CONSTRUCTION
DETAILS AND/OR
DRILLING REMARKS
Benzene (soil)(ppb)
PROJECT MANAGER:
PROJECT:
BORING IDENTIFICATION:
DRILLING CONTRACTOR:
DRILLING METHOD:
SAMPLING METHOD:
DRILLING EQUIPMENT:
REG. NO.
LOGGED BY:
DEPTH TO WATER:CASING:
TOTAL DEPTH:SCREEN INTERVAL:
DATE FINISHED:
DATE STARTED:
NORTHING:
EASTING:
ELEVATION:
May 18, 2023
May 18, 2023
50'
TVPH (soil)
(ppm)
AST Environmental Inc.Project No.Page 1 of 15152388
52
48
44
40
36
32
28
24
20
16
12
8
4
0
100
100
100
100
60
50
70
70
RDC-06 (11')
RDC-06 (13')
RDC-06 (15')
RDC-06 (17')
RDC-06 (19')
RDC-06 (21')
RDC-06 (23')
RDC-06 (25')
RDC-06 (27')
RDC-06 (29')
RDC-06 (31')
RDC-06 (33')
RDC-06 (35')
RDC-06 (37')
RDC-06 (39')
RDC-06 (41')
RDC-06 (43')
RDC-06 (45')
RDC-06 (47')
RDC-06 (49')
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<10
<0.5
<10
<0.5
<10
<10
<0.5
<0.5
<0.5
<0.5
<0.5
<10
110
160
CL
SC
CL
Geological logging not performed
Dry red sandy clay with tan mottling
Dry tan clayey sand
Dry tan/red sandy clay, white sand from 18'-19'
Dry tan/red sandy clay, some white mottling
Dry tan/white sandy clay, some red mottling, black
streaks from 26'-30'
Dry tan/white sandy clay, some red mottling, black
streaks
Gravelly clay, dark brown, dry, small < 5mm gravel
Gray/tan sandy clay, moist, some white horizontal
striations
Tan sandy clay, moist, with some small gravel,
white horizontal striations
Tan/white sandy clay, saturated, moderate odor
Tan sandy clay, moist, with some gravel, slight
odor
Boring Terminated 50'
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<10
<0.5
<10
<0.5
<10
<10
<0.5
<0.5
<0.5
<0.5
<0.5
<10
<50
<50
DESCRIPTION
NAME (USCS): color, sorting, plasticity,
moisture, sorting, grain size, packing
RDC-06
REC-OVERY(%)LAB I.D.DEPTH(feet)WELL CONSTRUCTION
DETAILS AND/OR
DRILLING REMARKS
Benzene (soil)(ppb)
PROJECT MANAGER:
PROJECT:
BORING IDENTIFICATION:
DRILLING CONTRACTOR:
DRILLING METHOD:
SAMPLING METHOD:
DRILLING EQUIPMENT:
REG. NO.
LOGGED BY:
DEPTH TO WATER:CASING:
TOTAL DEPTH:SCREEN INTERVAL:
DATE FINISHED:
DATE STARTED:
NORTHING:
EASTING:
ELEVATION:
May 18, 2023
May 18, 2023
50'
TVPH (soil)
(ppm)
Catlin - Best Stop #2
GEX
Direct Push
Geoprobe 7822
3.25 Dual Tube (10'-25') / Macrocore (25'-50')
Nathan Mau
Nathan Thacker
AST Environmental Inc.Project No.Page 1 of 15152388
52
48
44
40
36
32
28
24
20
16
12
8
4
0
80
0
50
80
70
50
90
RDC-07 (11')
RDC-07 (13')
RDC-07 (15')
RDC-07 (17')
RDC-07 (19')
RDC-07 (25')
RDC-07 (27')
RDC-07 (29')
RDC-07 (31')
RDC-07 (33')
RDC-07 (35')
RDC-07 (37')
RDC-07 (39')
RDC-07 (41')
RDC-07 (43')
RDC-07 (45')
RDC-07 (47')
RDC-07 (49')
<0.5
<10
<0.5
<0.5
<0.5
2.5
<0.5
<0.5
<10
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
CL
SC
CL
CL
Geological logging not performed
Red sandy clay, dry, with tan mottling
Red sandy clay, dry, with tan mottling, more tan sandy clay 18'-20'
No recovery
Tan/white sandy clay, dry, some small gravel at 27'
Red/gray sandy clay, dry, some small gravel
30'-32', white mottling and black streaking
throughout
Gray/tan sandy clay, thick (~9") zone of black
staining/mineralization at 37', more red present
below that
Gray/tan/red sandy clay, moist
Small gravel and black mineralization over brown
clayey sand
Red/tan sandy clay, moist
Red/tan sandy clay, moist, some horizontal black
striations throughout
Red/tan sandy clay, wet, white mottling and moist
49'-50', some horizontal black striations
throughout, gravel interspersed
Boring Terminated 50'
<0.5
<10
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<10
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
DESCRIPTION
NAME (USCS): color, sorting, plasticity,
moisture, sorting, grain size, packing
RDC-07
REC-OVERY(%)LAB I.D.DEPTH(feet)WELL CONSTRUCTION
DETAILS AND/OR
DRILLING REMARKS
Benzene (soil)(ppb)
PROJECT MANAGER:
PROJECT:
BORING IDENTIFICATION:
DRILLING CONTRACTOR:
DRILLING METHOD:
SAMPLING METHOD:
DRILLING EQUIPMENT:
REG. NO.
LOGGED BY:
DEPTH TO WATER:CASING:
TOTAL DEPTH:SCREEN INTERVAL:
DATE FINISHED:
DATE STARTED:
NORTHING:
EASTING:
ELEVATION:
May 18, 2023
May 18, 2023
50'
TVPH (soil)
(ppm)
Catlin - Best Stop #2
GEX
Direct Push
Geoprobe 7822
Macrocore
Nathan Mau
Nathan Thacker
AST Environmental Inc.Project No.Page 1 of 15152388

Attachment C
BOS 200 Injection Design

Monitoring Well
Recovery Well
RDC Soil Boring
Legend
AST Environmental
1567 CF Pours Drive
Harrisonburg, Virginia
www.astenv.com
Best Stop 2
10014 Lancaster Highway
Waxhaw, North Carolina
NCDEQ Incident #27776
Client Name NCDEQ
Project Location Best Stop #2, Waxhaw, NC
Area A
MW-01
Site Information Predominate Geology of Treatment Zone
Treatment Zone Area (ft^2)1,770 1,770
Contamination Depth Start (ft bgs)29.0
Contamination Depth End (ft bgs)45.0
Treatment Volume (yd^3)1,048.9 1,049
Triangular Grid Spacing (ft)7.5
Number of Injection Points - Design 32 32
Injection Interval Distance (ft)1.5
Number of Injection Intervals per Point - Design 12.0
Total Number of Injection Intervals 384 384
Effective Porosity 30%
Pore Volume (L)240,607
Soil Density (lb/ft^3)110
Speciated COC Design Calculations Contaminant of Concern Benzene
Design Basis Soil (mg/kg) or Groundwater (mg/L)Groundwater
Design Concentration 4.200
Design Endpoint (Interim)0.050
Contaminant of Concern Mass Loading (lb/ft^3)7.86E-05
BOS 200 per Injection Interval - Design (lb)50
BOS 200 Slurry Volume per Interval (gal)25
Average BOS 200 per Injection Point (lb)600
BOS 200 Total (lb)19,200 19,200
TPH Design Calculations TPH Groundwater Concentration (mg/L)120
TPH Soil Concentration (mg/kg)1,900
TPH Mass (lb)5,995
BOS 200 per Injection Interval - Design (lb)30
BOS 200 Slurry Volume per Interval (gal)25
Average BOS 200 per Injection Point (lb)360
BOS 200 Total (lb)11,520 11,550
Design Basis Select Speciated or TPH Speciated
Design BOS 200 Total per Area (lb)19,200 19,200
Trap & Treat Bacteria Calculations Bacteria Concentrate (gal)38 40
Kinetic Design Additives Supplemental Gypsum per Interval - Design (lb)25
Total Supplemental Gypsum (lb)9,600 9,600
Supplemental Magnesium Sulfate per Interval - Design (lb)25
Total Supplemental Magnesium Sulfate (lb)9,600 9,600
Food Grade Starch per Interval (lb)12.5
Total Food Grade Starch (lb)4,800 4,800
Yeast Extract per Interval (lb)0.33
Total Yeast Extract (lb)127 165
Slurry and Water Volumes Slurry Volume per Interval (gal)25
Estimated Water Volume (gal)9,600 9,600
Totals
7/13/2023
Client Name NCDEQ
Project Location Best Stop #2, Waxhaw, NC
Area B
MW-05
Site Information Predominate Geology of Treatment Zone
Treatment Zone Area (ft^2)1,450 1,450
Contamination Depth Start (ft bgs)30.0
Contamination Depth End (ft bgs)49.0
Treatment Volume (yd^3)1,020.4 1,020
Triangular Grid Spacing (ft)7.5
Number of Injection Points - Design 26 26
Injection Interval Distance (ft)1.5
Number of Injection Intervals per Point - Design 13.5
Total Number of Injection Intervals 351 351
Effective Porosity 30%
Pore Volume (L)234,065
Soil Density (lb/ft^3)110
Speciated COC Design Calculations Contaminant of Concern Benzene
Design Basis Soil (mg/kg) or Groundwater (mg/L)Groundwater
Design Concentration 2.000
Design Endpoint (Interim)0.025
Contaminant of Concern Mass Loading (lb/ft^3)3.74E-05
BOS 200 per Injection Interval - Design (lb)40
BOS 200 Slurry Volume per Interval (gal)25
Average BOS 200 per Injection Point (lb)540
BOS 200 Total (lb)14,040 14,050
TPH Design Calculations TPH Groundwater Concentration (mg/L)63
TPH Soil Concentration (mg/kg)1,400
TPH Mass (lb)4,284
BOS 200 per Injection Interval - Design (lb)30
BOS 200 Slurry Volume per Interval (gal)25
Average BOS 200 per Injection Point (lb)405
BOS 200 Total (lb)10,530 10,550
Design Basis Select Speciated or TPH Speciated
Design BOS 200 Total per Area (lb)14,040 14,050
Trap & Treat Bacteria Calculations Bacteria Concentrate (gal)28 30
Kinetic Design Additives Supplemental Gypsum per Interval - Design (lb)25
Total Supplemental Gypsum (lb)8,775 8,800
Supplemental Magnesium Sulfate per Interval - Design (lb)25
Total Supplemental Magnesium Sulfate (lb)8,775 8,800
Food Grade Starch per Interval (lb)12.5
Total Food Grade Starch (lb)4,388 4,400
Yeast Extract per Interval (lb)0.33
Total Yeast Extract (lb)116 165
Slurry and Water Volumes Slurry Volume per Interval (gal)25
Estimated Water Volume (gal)8,775 8,775
Totals
7/13/2023
Client Name NCDEQ
Project Location Best Stop #2, Waxhaw, NC
Area C
RDC-04
Site Information Predominate Geology of Treatment Zone Saprolite
Treatment Zone Area (ft^2)1,100 1,100
Contamination Depth Start (ft bgs)33.0
Contamination Depth End (ft bgs)38.0
Treatment Volume (yd^3)203.7 204
Triangular Grid Spacing (ft)7.5
Number of Injection Points - Design 20 20
Injection Interval Distance (ft)1.5
Number of Injection Intervals per Point - Design 4.0
Total Number of Injection Intervals 80 80
Effective Porosity 30%
Pore Volume (L)46,728
Soil Density (lb/ft^3)110
Speciated COC Design Calculations Contaminant of Concern Benzene
Design Basis Soil (mg/kg) or Groundwater (mg/L)Groundwater
Design Concentration 0.019
Design Endpoint 0.001
Contaminant of Concern Mass Loading (lb/ft^3)3.56E-07
BOS 200 per Injection Interval - Design (lb)25
BOS 200 Slurry Volume per Interval (gal)25
Average BOS 200 per Injection Point (lb)100
BOS 200 Total (lb)2,000 2,000
Design Basis Select Speciated or TPH Speciated
Design BOS 200 Total per Area (lb)2,000 2,000
Trap & Treat Bacteria Calculations Bacteria Concentrate (gal)4 5
Slurry and Water Volumes Slurry Volume per Interval (gal)25
Estimated Water Volume (gal)2,000 2,000
Summary BOS 200 Total (lb)2,000
BOS 200 Unit Price ($, per RPI website)$6.25
Bacteria Concentrate (gal)5
Bacteria Concentrate Price ($, per RPI website)$115.00
Estimated Shipping and Tax ($/lb)$0.35
Total Material Price ($)$13,775
Number of Field Days to Complete 3
Mobilization ($)$3,500
Injection Location Markout ($)
Total Installation Price ($)$26,000
Total Estimated Price ($)$39,775
Totals
7/13/2023
Client Name NCDEQ
Project Location Best Stop #2, Waxhaw, NC
Area D
MW-02
Site Information Predominate Geology of Treatment Zone Saprolite
Treatment Zone Area (ft^2)1,370 1,370
Contamination Depth Start (ft bgs)46.0
Contamination Depth End (ft bgs)50.0
Treatment Volume (yd^3)203.0 203
Triangular Grid Spacing (ft)7.5
Number of Injection Points - Design 24 24
Injection Interval Distance (ft)1.5
Number of Injection Intervals per Point - Design 3.5
Total Number of Injection Intervals 84 84
Effective Porosity 30%
Pore Volume (L)46,558
Soil Density (lb/ft^3)110
Speciated COC Design Calculations Contaminant of Concern Benzene
Design Basis Soil (mg/kg) or Groundwater (mg/L)Groundwater
Design Concentration 0.067
Design Endpoint 0.001
Contaminant of Concern Mass Loading (lb/ft^3)1.25E-06
BOS 200 per Injection Interval - Design (lb)35
BOS 200 Slurry Volume per Interval (gal)25
Average BOS 200 per Injection Point (lb)123
BOS 200 Total (lb)2,940 2,950
Design Basis Select Speciated or TPH Speciated
Design BOS 200 Total per Area (lb)2,940 2,950
Trap & Treat Bacteria Calculations Bacteria Concentrate (gal)6 10
Slurry and Water Volumes Slurry Volume per Interval (gal)25
Estimated Water Volume (gal)2,100 2,100
Summary BOS 200 Total (lb)2,950
BOS 200 Unit Price ($, per RPI website)$6.25
Bacteria Concentrate (gal)10
Bacteria Concentrate Price ($, per RPI website)$115.00
Estimated Shipping and Tax ($/lb)$0.35
Total Material Price ($)$20,620
Number of Field Days to Complete 4
Mobilization ($)$3,500
Injection Location Markout ($)
Total Installation Price ($)$33,500
Total Estimated Price ($)$54,120
Totals
7/13/2023