23076_RalMGP2_VIAWP_20210329

Mid Atlantic
Engineering & Environmental Solutions
March 29, 2021
Hayley Irick
NC Brownfields Program
NC Department of Environmental Quality
Division of Waste Management
Mail Service Center 1646
Raleigh, North Carolina 27699-1646
Subject: SUB -SLAB SOIL GAS ASSESSMENT WORK PLAN
FORMER RALEIGH MGP NO. 2
600 CABARRUS STREET
RALEIGH, NORTH CAROLINA
BROWNFIELDS PROJECT NO.: 13022-09-92
MID -ATLANTIC PE LICENSE: F-0967
REVISION NO.: 0
MID -ATLANTIC JOB NO. 00OR3746.00
Dear Ms. Irick:
409 Rogers View Court
Raleigh. NC 27610
office 919,250.9918
Facsimile 919.250.99SO
MAAONLINE.COM
On behalf of Cabarrus LLC, Mid -Atlantic Associates, Inc. (Mid -Atlantic) has prepared this
Sub -Slab Soil Gas Assessment Work Plan associated with the redevelopment project
Former Raleigh MGP No. 2 located at 600 Cabarrus Street in Raleigh, North Carolina
(Drawing 1). The objective of this Work Plan is to outline environmental assessment
activities requested by the North Carolina Brownfields Program (NCBP) to establish
`baseline' sub -slab soil gas conditions at the Clancy Shop and Amtrak buildings on the
site.
INTRODUCTION
The subject site is comprised of three parcels totaling 5.91 acres and situated northwest of
the intersection of South West Street and West Cabarrus Street (600 Cabarrus Street) in
Raleigh, North Carolina. In 2011 a Brownfield Agreement was completed for a 4.08-acre
portion of the subject site. The Department of Environmental Quality (DEQ) has
— EXPERIENCED CUSTOMER FOCUSED INNOVATIVE —

Sub -Slab Soil Gas Assessment Work Plan
Former Raleigh MGP Site 2
Raleigh, North Carolina
March 29, 2021
Page 2
determined that the remaining 1.83 acres associated with the subject site can participate in
the Brownfield Program. The process of consolidating the entire 5.91 acres into the
existing Brownfield Agreement is currently underway.
The subject site has been used for various industrial purposes, including a manufactured
gas plant, since the late 1800s. Environmental assessment activities conducted at the
subject site have identified the presence of volatile organic compounds (VOCs) in the soil
and groundwater at the site. Both chlorinated and petroleum -related VOCs have been
identified in the groundwater at the site.
Mr. John Gallagher, PE, a representative of the Prospective Developer, and the NCBP
have agreed that assessing sub -slab soil gas conditions at the Clancy Shop and the
Amtrak Building would provide `baseline' data related to the potential for vapor intrusion
issues at the site. This Work Plan was developed to collect the data requested by the
NCBP.
SCOPE OF WORK
Mid -Atlantic proposes the following scope of work:
• Collect a total of six sub -slab soil gas samples (Drawing 2). Three sub -slab soil
gas samples will be collected in the Clancy Shop (approximately 5,600 ft2) and
three sub -slab soil gas samples will be collected in the Amtrack Building
(approximately 8,700 ft2).
• Preparation of a Sub -Slab Soil Gas Assessment Report to document field activities
and provide analysis of the data collected.
SAMPLING METHODOLOGY
At each sub -slab location, a rotary -impact drill equipped with a decontaminated spline
drill bit will be utilized to drill a 5/8-inch diameter hole through the concrete slab. At each
location the field technician will log the materials and condition beneath the slab. A
vapor sampling probe will be established using a new "Vapor Pin TM", a brass barb fitting
with a silicone sleeve that creates a seal with the concrete when inserted using an
installation/extraction tool. The Vapor Pin will then be fitted with 1/4-inch outer diameter
rigid -wall Teflon tubing to complete the vapor sampling probe assembly. A leak check
will be performed at each probe location using a plastic shroud, helium gas, and a
portable helium gas detector. A plastic shroud will be placed over the sub -slab vapor
probe location with the tubing of the probe exiting the shroud through a small hole. A 3-
way valve will be placed on the probe termination and connected to the sampling
apparatus. Helium will be released into the shroud via tubing from the cylinder, and a
Mid Atlantic

Sub -Slab Soil Gas Assessment Work Plan
Former Raleigh MGP Site 2
Raleigh, North Carolina
March 29, 2021
Page 3
grab sample collected by filling a Tedlar bag using the exhaust port of the purge
syringe. Sub -slab samples will then be collected using 1-liter stainless steel canisters at
a maximum flow rate of 200 milliliters per minute (ml/min). Mid -Atlantic will fill the
laboratory provided Summa canister such that the final vacuum in the canister is at least
three to four inches of mercury. The sub -slab samples will be collected in accordance
with the NCDEQ Division of Waste Management (DWM) Vapor Intrusion Guidance
Document (March 2018).
LABORATORY ANALYSIS
The soil gas samples will be submitted to Pace Analytical Laboratory (Pace) of Mount
Juliette, Tennessee for analysis. Soil gas samples will be analyzed for VOCs in
accordance with the EPA Compendium Method TO-15. The sampling and analysis plan
for soil gas is summarized in Table 1. Reporting limits and method detection limits will
meet applicable screening criteria including the reporting of estimated concentrations as
"J" flags. Laboratory Level II QA/QC will be provided.
QA/QC
One duplicate sub -slab soil gas sample will be collected in the field. The duplicate sample
will be analyzed for EPA Compendium Method TO-15 (Table 1). The laboratory provided
Summa canister will be closed with a final vacuum in the canister is at least three to four
inches of mercury to assist in the evaluation of sample integrity during transit. The chain -
of -custody will be completed in the field and packed with the samples. The Mid -Atlantic
field technician will return to the office with the packed boxes which will be shipped to the
laboratory located in Mount Juliette, Tennessee.
INVESTIGATION DERIVED WASTE OQW) MANAGEMENT
Investigation derived waste, aside from de minimus amounts of concrete, will not be
generated during this assessment.
REPORTING
Following completion of assessment field activities and receipt of laboratory analytical
data, Mid -Atlantic will prepare a Soil Gas Assessment Report to document field activities
and provide analysis of the data collected. Each concentration detected in the sub -slab soil
gas samples collected will be evaluated using the NCDEQ risk calculator for cumulative
risk evaluation(s). At a minimum, the reports will include:
Mid Atlantic

Sub -Slab Soil Gas Assessment Work Plan
Former Raleigh MGP Site 2
Raleigh, North Carolina
March 29, 2021
Page 4
• Reporting/summary of site work conducted for all sections outlined above;
• Summary of findings and possible recommendations;
• All applicable tables and figures including tabulated analytical data, cumulative risk
evaluations, and figures depicting sample locations;
• Mid -Atlantic's PE/PG License Number; and
• The Professional Engineer's or Licensed Geologist's individual PE/LG seal and
signature.
CLOSING
We appreciate the opportunity to submit this Work Plan. Should you have any questions
please do not hesitate to reach me at 919-250-9918.
Sincerely,
MID-ATLANTI e OCIATES, INC.
D Nielsen
Principal fd�uoy,�
NCPE Licens�,l6:F{l'8tl�,
�®'®'aao-�AbA4�wu
Darin M. McClure, PE
Principal Engineer
Attachments: Table 1 — Sampling and Analysis Plan
Drawing 1 —Topographic Site Map
Drawing 2 — Proposed Sampling Locations
0 Mid Atlantic

TABLE
0 Mid Atlantic

TABLE 1
SAMLPING AND ANALYSIS PLAN
SUB -SLAB SOIL GAS ASSESSMENT
FORMER RALEIGH MGP NO. 2
600 CABARRUS STREET
RALEIGH, NORTH CAROLINA
Analysis
EPA Method
TO-15
Samples
Samples Location
Sample ID
Proposed # of
Samples
Proposed Sample
Interval
SG-1
1
Sub -slab
1
SG-2
1
Sub -slab
1
Clancy Shop
SG-3
1
Sub -slab
1
Soil Gas Samples
SG-4
1
Sub -slab
1
SG-5
1
Sub -slab
1
Amtrak Building
SG-6
1
Sub -slab
1
Duplicate Samples
1
TOTALS:
7

DRAWINGS
0 Mid Atlantic

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REFERENCES:
1. RALEIGH WEST, NC DIGITAL RASTER GRAPHICS,
USGS. SCANNED FROM 1:24,000-SCALE WAKE, NC
TOPOGRAPHIC MAPS, PUBLISHED 2019, USGS. SCALE: 1:9,000
2. INSET MAP DIGITAL DATA FROM 2002 NATIONAL TRANSPORTATION ATLAS, Feet
BUREAU OF TRANSPORTATION STATISTICS, WASHINGTON, D.C. 6OO 1,ZOO
3. PROPERTY BOUNDARY DATA FROM WAKE COUNTY GIS.
DRAWN DATE:
TOPOGRAPHIC SITE MAP BY: GCH MARCH 2O21
FORMER RALEIGH MGP SITE NO. 2 DRAFT JOB NO:
Mid Atlantic 600 W CABARRUS STREET CHECK: OOOR3746.01
Engineering & Environmental Solutions ENG. GIS NO:
RALEIGH, NORTH CAROLINA
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Legend
O Proposed Sub Slab Locations
Subject Property
Property Boundaries3
,
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REFERENCES:
1. MID -ATLANTIC FIELD NOTES.
2. NCONE MAP LATEST ORTHOIMAGERY
3. PROPERTY BOUNDARY AND ROAD SHAPEFILES
SCALE:1 inch equals 100
feet
PROVIDED BY WAKE COUNTY GIs
Feet
0
100
200
PROPOSED SAMPLE LOCATION MAP
DRAWN
BY:
GCH
DATE:
MARCH 2O21
DRAFT
CHECK:
JOB NO:
OOOR3746.00
Mid Atlantic
Engineering & Environmental Solutions
FORMER RALEIGH MGP NO. 2
600 W CABARRUS STREET
RALEIGH, NORTH CAROLINA
ENG.
CHECK:
GIs NO:
2G-R3746.00-2
APPROVAL:
DWG NO: 2