23064_Dick Keffer Pontiac_VI Assessment Work Plan Approval Package_20220607

June 7, 2022 Sent Via E-mail
William Morris Tapestry Tyvola, LLC 2 North 20th Street, Suite 700 Birmingham, AL 35203 [e-mail]

Subject: Vapor Intrusion Assessment Work Plan Approval Dick Keffer Pontiac Buick GMC 1001 Tyvola Road and 450 Minuet Lane Charlotte, Mecklenburg County
Brownfields Project Number 23064-19-060 Dear Mr. Morris: The North Carolina Department of Environmental Quality (DEQ) Brownfields Program received
and reviewed the June 3, 2022, Vapor Intrusion Assessment Work Plan submitted by Hart & Hickman for the above referenced Brownfields Project. Based on our review, the Vapor Intrusion Assessment Work Plan is approved.
Be advised that this approval from the Brownfields Program does not waive any applicable
requirement to obtain any necessary permits, licenses, or certifications for the above referenced activities nor does it waive any requirement to comply with applicable law for such activities. If you have any questions, please feel free to contact me via e-mail at [e-mail].
Sincerely,
Peter L. Doorn Brownfields Project Manager ec: Brett Lawrence, Hart & Hickman Kevin Slaughter, NC DEQ
Tracy Wahl, NC DEQ

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Vapor Intrusion Assessment Work Plan Dick Keffer Pontiac Buick GMC
1001 Tyvola Road and 450 Minuet Lane Charlotte, North Carolina Brownfields Project No.: 23064-19-060 H&H Job No. ARL-001
Table of Contents
Section Page No. 1.0 Introduction ............................................................................................................................ 1
2.0 Vapor Intrusion Assessment Scope of Work ....................................................................... 2
2.1 Sub-Slab Vapor Assessment ................................................................................................. 2
2.2 Indoor Air Assessment (If Warranted) ................................................................................. 4
2.3 Quality Assurance/Quality Control ...................................................................................... 5
2.4 Proposed Sampling Schedule ............................................................................................... 6
3.0 Reporting ................................................................................................................................ 7

Table
Table 1 Proposed Sample Summary

List of Figures
Figure 1 Site Location Map
Figure 2 Proposed Sample Location Map

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Vapor Intrusion Assessment Work Plan Dick Keffer Pontiac Buick GMC
1001 Tyvola Road and 450 Minuet Lane Charlotte, North Carolina Brownfields Project No.: 23064-19-060 H&H Job No. ARL-001

1.0 Introduction

On behalf of Tapestry Tyvola, LLC (Prospective Developer or PD), Hart & Hickman, PC (H&H)
has prepared this Work Plan to conduct vapor intrusion assessment activities at the Dick Keffer
Pontiac Buick GMC Brownfields property located at 1001 Tyvola Road and 450 Minuet Lane in
Charlotte, Mecklenburg County, North Carolina (Site). The Site is in the North Carolina
Department of Environmental Quality (DEQ) Brownfields Program (Project Number: 23064-19-
060).

The Site consists of two contiguous parcels (Parcel Identification Numbers: 16908402 and
16908410) that total approximately 10.5 acres. The Site is being redeveloped with four multi-
family apartment buildings and associated amenities (Building 1 through Building 4), two public
streets, and surface parking. An unnamed tributary to Kings Branch traverses the northwest
portion of the Site. A Site location map is included as Figure 1.

A Notice of Brownfields Property, which includes a Brownfields Agreement, was recorded for the
Site at the Mecklenburg County Register of Deeds on December 29, 2021. The Land Use
Restriction (LUR) presented in paragraph 12.k. of the Brownfields Agreement generally states that
permanent sub-slab monitoring points are to be installed and sampled for a minimum of four
consecutive semi-annual events to evaluate the potential for vapor intrusion associated with the
newly constructed apartment buildings at the Site. This Work Plan has been prepared in
accordance with paragraph 12.k. of the Brownfields Agreement.

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2.0 Vapor Intrusion Assessment Scope of Work

The vapor intrusion assessment activities will be performed in general accordance with DEQ’s
Inactive Hazardous Sites Branch (IHSB) Guidelines for Assessment and Cleanup (Guidelines)
dated July 2021, the DEQ DWM Vapor Intrusion Guidance dated March 2018, and most recent
versions of the U.S. Environmental Protection Agency (EPA) Region IV Laboratory Services and
Applied Science Division (LSASD) guidance.

Prior to conducting field activities, H&H will contact NC One-Call, the public utility locator, to
mark subsurface utilities at the Site. H&H will also contract with a private utility locating company
to identify and mark locations of subsurface utilities near proposed sub-slab vapor sample
locations. A proposed sample table is included as Table 1 and the proposed sample locations are
depicted on Figure 2. Our proposed scope of work is presented in the following sections.

2.1 Sub-Slab Vapor Assessment

To further evaluate the potential for vapor intrusion associated with the newly constructed Site
buildings, H&H proposes to install and sample 16 permanent sub-slab monitoring points (SSV-1
through SSV-16). The sub-slab monitoring points will be installed using a rotary hammer drill
and 1½-inch diameter drill bit to advance a pilot hole into the concrete slab to a depth of
approximately 1¾ inches below the surface. A drill guide will then be placed in the pilot hole, and
a 5/8-inch diameter drill bit will be utilized to advance the boring through the concrete slab and
approximately 6 inches into the underlying soil. Following concrete borehole advancement, loose
concrete cuttings will be removed from each boring, and a Cox-Colvin Vapor Pin™ (vapor pin)
assembly (brass sampling point and silicone sleeve) will be seated in the borehole using an
installation/extraction tool and dead blow hammer.

The sub-slab soil gas samples will be collected utilizing laboratory supplied, batch-certified
Summa® canisters (1- or 3-liter canisters depending on laboratory availability) connected to an

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air-flow regulator calibrated by the laboratory to collect the sample at a rate of approximately 100
milliliters per minute (ml/min). Prior to collection of the soil gas samples, a “shut-in” test will be
conducted on the sampling train and helium leak checks will be conducted at each soil gas
sampling point. The purpose of the shut-in test and helium leak check is to ensure short circuiting
with ambient air does not occur during sampling. A description of the shut-in test and helium leak
testing procedures is provided below.

The shut-in test will be conducted by connecting the flow regulator with the vacuum gauge to the
Summa® canister and sealing the flow regulator with the laboratory provided brass cap. Once the
sampling train is “closed”, the sample valve on the Summa® canister will be opened and the
reading on the vacuum gauge will be recorded. The Summa® canister sample valve will then be
closed, and the vacuum gauge will be observed to ensure no vacuum loss occurs. If the vacuum
reading remains the same, the shut-in test will be considered successful. If vacuum loss occurs,
the flow regulator and/or brass cap will be reseated, and the shut-in test will be repeated until the
vacuum reading remains stable.

Following the shut-in test, the Summa® canister will be connected to the sample point via Teflon®
sample tubing using a brass nut and ferrule assembly to create an airtight seal and the leak check
will be performed. The leak check will be performed by constructing a shroud over the sampling
train and flooding the shroud with helium gas. A calibrated helium gas detector will be utilized to
measure helium concentrations within the shroud. Once helium concentrations stabilize within the
shroud, the sample tubing will be purged outside of the shroud using a syringe and a three-way
valve to collect purged soil gas into a Tedlar® bag. The purged soil gas will then be analyzed
using the helium gas detector to ensure that helium concentrations in the monitoring point are less
than 10% of the helium concentrations measured within the shroud.

Following successful leak checks, the valve on the flow regulator will be fully opened to allow
collection of the sub-slab soil gas samples. Vacuum readings on each Summa® canister will be
recorded prior to and following the sampling period to ensure adequate sample volume was
collected. A vacuum of approximately 5 inches of mercury or more will be maintained within the

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canisters at the conclusion of the sampling event in accordance with DEQ DWM guidance.
Following sample collection, the Summa® canisters will be shipped to a nationally-accredited
laboratory under standard chain of custody protocols for analysis of volatile organic compounds
(VOCs) by EPA Method TO-15. The laboratory will be requested to use reporting limits that are
below DEQ DWM Residential Vapor Intrusion Soil Gas Screening Levels (SGSLs).

2.2 Indoor Air Assessment (If Warranted)

Indoor air assessment of the newly constructed Site buildings is not proposed at this time.
However, per paragraph 12.k. of the Brownfields Agreement, indoor air assessment may be
required in the future based on the results of sub-slab vapor assessment and as determined by DEQ.
Therefore, indoor air sampling methodology has been included in this Work Plan.

In addition to any indoor air samples, an exterior background ambient air sample will be collected
at the time of the indoor air sampling event. As part of any future indoor air assessment activities,
H&H will conduct a survey of the Site building(s) to identify materials within the building(s) that
may be indoor sources of potential compounds of concern.

The background and indoor air samples will be collected using 6-liter stainless steel batch-certified
Summa® canisters connected to in-line flow controllers with a vacuum gauge. The flow
controllers will be set by the laboratory to allow for collection of the samples over an 8-hour period.
A 3-foot-long sampling cane will be connected to the flow controller so that the sample intake
point is positioned approximately 5 feet above grade (typical breathing zone height) when the
sample canister is set on its base.

During the sampling activities, indoor/outdoor air pressure differential will be measured for each
building near the start, middle, and end of the 8-hour sampling period using a manometer sensitive
to 0.001 inches of water. In addition, Site-specific weather conditions including exterior wind
speed, exterior wind direction, indoor/outdoor temperature, barometric pressure, and precipitation
(if any) will be recorded near the start, middle, and end of the sampling period. Based upon the

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wind measurements, the exterior background sample location will be collected in an upwind
location on the Site.

Prior to and after the indoor and background air samples are collected, vacuum in the canisters will
be measured using a laboratory supplied vacuum gauge and recorded by sampling personnel on
the sample chain-of-custody. The sample canisters will then be labeled, packaged in a laboratory-
provided container, and shipped under standard chain-of-custody protocols to a nationally-
accredited laboratory for analysis of a select list of VOCs by EPA Method TO-15. The select list
will be based on compounds detected in soil gas samples collected at the Site.

2.3 Quality Assurance/Quality Control

For field and laboratory quality assurance/quality control (QA/QC) purposes, H&H will collect
one duplicate sample per sampling event for laboratory analysis of VOCs by EPA Method TO-15.

Laboratory QA/QC procedures will be employed to ensure appropriate sample handling and
analysis and to aid in the review and validation of the analytical data. QA/QC procedures will be
conducted in accordance with the method protocols and will include regular equipment
maintenance, equipment calibrations, and adherence to specific sample custody and data
management procedures. Samples will be analyzed in conjunction with appropriate blanks,
laboratory duplicates, continuing calibration standards, surrogate standards, and matrix spiking
standards in accordance with approved methodologies to monitor both instrument and analyst
performance. Laboratory reporting limits for each analyte will be at or below appropriate
screening criteria, where possible. Additionally, H&H will request that the laboratory include
estimated concentrations for compounds that are detected at levels above the laboratory method
detection limit, but below the laboratory reporting limit (J flags).

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2.4 Proposed Sampling Schedule

Per paragraph 12.k. of the Brownfields Agreement, a minimum of four consecutive semi-annual
sampling events are to be conducted. The semi-annual sampling schedule is to include both warm
and cold weather sampling events. H&H proposes to conduct Site-wide sampling of the permanent
sub-slab vapor monitoring points based on the following schedule:

• First Sampling Event – Summer 2022 (within one-month of sub-slab
monitoring point installation and prior to planned occupancy of the Site
buildings)
• Second Sampling Event – Winter 2022
• Third Sampling Event – Summer 2023
• Fourth Sampling Event – Winter 2023

Following the fourth consecutive sampling event (winter 2023) and provided that Site-wide vapor
intrusion risk has remained consistent or has decreased following each sampling event, H&H will
propose for DEQ’s written consideration the relaxation or cessation of monitoring requirements at
the Site.

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3.0 Reporting

Upon completion of the field activities and receipt of the analytical data for each sampling event,
H&H will prepare a report which describes the methods and results of the vapor intrusion
assessment activities. The report will include a description of field activities, a figure depicting
the sample locations, a tabular summary of the analytical results in comparison to regulatory
screening levels, cumulative risk calculations, laboratory analytical reports including chain of
custody records and sample receipt documents, a discussion of QA/QC data, and conclusions based
upon our assessment activities. The report will be sealed by a North Carolina professional engineer
(PE) or licensed geologist (LG) and the firm’s PE/LG numbers will be provided.

Table
Table 1Proposed Sample TableDick Keffer Pontiac Buick GMC1001 Tyvola Road and 450 Minuet LaneCharlotte, North CarolinaBrownfields Project No: 23064-19-060H&H Job No. ARL-001General Site LocationSample ObjectiveSample IDNumber of Sample LocationsSample MediaProposed Sample Depth (feet)VOCs by EPA Method TO-15Duplicate SampleFour Sub-Slab VMPs Per BuildingFuture Resident/ Occupant Risk AssessmentSSV-1 through SSV-1616Soil Vapor 0.5 (Sub-Slab) XXNotes:VOCs = volatile organic compoundsEPA = Environmental Protection Agencyhttps://harthick.sharepoint.com/sites/MasterFiles-1/Shared Documents/AAA-Master Projects/Arlington Properties (ARL)/ARL-001 Dick Keffer Brownfields/Vapor Assessment/Work Plan/Proposed Sample Table13/31/2022Table 1 (Page 1 of 1) Hart & Hickman, PC

Figures
USGS The National Map: National Boundaries Dataset, 3DEP ElevationProgram, Geographic Names Information System, National HydrographyDataset, National Land Cover Database, National Structures Dataset, andNational Transportation Dataset; USGS Global Ecosystems; U.S. CensusBureau TIGER/Line data; USFS Road Data; Natural Earth Data; U.S.Department of State Humanitarian Information Unit; and NOAA NationalCenters for Environmental Information, U.S. Coastal Relief Model. Datarefreshed August, 2021.
SITE LOCATION MAP
DICK KEFFER BROWNFIELDS SITE1001 TYVOLA ROAD & 450 MINUET LANECHARLOTTE, NORTH CAROLINA
DATE: 3-7-22
JOB NO: ARL-001
REVISION NO: 0
FIGURE NO: 1
2923 South Tryon Street - Suite 100Charlotte, North Carolina 28203704-586-0007 (p) 704-586-0373 (f)License # C-1269 / # C-245 Geology
TITLE
PROJECT
0 2,000 4,000
SCALE IN FEET
SITE
Path: S:\AAA-Master Projects\Arlington Properties (ARL)\ARL-001 Dick Keffer Brownfields\Figures\Figure-1.mxdN
U.S.G.S. QUADRANGLE MAP
CHARLOTTE WEST, NORTH CAROLINA 2019
QUADRANGLE7.5 MINUTE SERIES (TOPOGRAPHIC)
REVISION NO. 0
JOB NO. ARL-001
DATE: 4-5-22
FIGURE NO. 2
DICK KEFFER BROWNFIELDS SITE1001 TYVOLA ROAD AND 450 MINUET LANECHARLOTTE, NORTH CAROLINA
PROPOSED SAMPLE LOCATION MAP
LEGEND
PROPERTY BOUNDARY
PARCEL BOUNDARY
RAILROAD
FENCE LINE
BUILDING FOOTPRINT
PROPOSED SUB-SLAB SAMPLE
2923 South Tryon Street-Suite 100Charlotte, North Carolina 28203704-586-0007(p) 704-586-0373(f)License # C-1269 / #C-245 Geology
NOTES:
1. BASE MAP OBTAINED FROM CAROLINA SURVEYORS,INC. PROPERTY SURVEY DATED 12/10/2018.
TYVOLA ROAD OLD PINEVILLE ROADSSV-1
SSV-3
SSV-5
SSV-8
SSV-9
SSV-13 SSV-15
MINUE
T
L
A
N
E
SSV-2 SSV-4
SSV-6
SSV-7
SSV-10
SSV-11SSV-12
SSV-14 SSV-16
S:\AAA-Master Projects\Arlington Properties (ARL)\ARL-001 Dick Keffer Brownfields\Figures\Vapor Assessment\Proposed Sam Loc Map 20220401.dwg, PROPOSED.SAMPLES (2), 5/26/2022 3:57:29 PM, akairy