14038 Clarkson Additional SV Report 20110330

Additional Soil Vapor
Assessment Report
Clarkson Street Site
Charlotte, North Carolina
Brownfields Project No. 14038-10-60

H&H Job No. BEZ-002

March 30, 2011

2923 South Tryon Street
Suite 100
Charlotte, NC 28203 704-586-0007

3334 Hillsborough Street Raleigh, NC 27607
919-847-4241 #C-1269 Engineering
#C-245 Geology

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Additional Soil Vapor Assessment Report Clarkson Street Site
Charlotte, North Carolina
H&H Job No. BEZ-002 Table of Contents
Section Page No.

1.0 Introduction ............................................................................................................................ 1
2.0 Soil Vapor Assessment ........................................................................................................... 3
2.1 Soil Vapor Sampling Methods ............................................................................................. 3
2.2 Soil Vapor Results ............................................................................................................... 5

List of Tables
Table 1 Summary of Soil Vapor Analytical Detections

List of Figures
Figure 1 Site Location Map
Figure 2 Soil Vapor Monitoring Point Location Map

List of Appendices
Appendix A Laboratory Analytical Data
1
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Additional Soil Vapor Assessment Report
Clarkson Street Site Charlotte, North Carolina H&H Job No. BEZ-002
1.0 Introduction

This report presents the results of additional soil vapor assessment conducted by Hart &
Hickman, PC (H&H) at the Clarkson Street Site located in Charlotte, North Carolina. A site
location map is provided as Figure 1, and a site map is provided as Figure 2. As indicated in
Figure 2, the site consists of multiple land parcels along West Morehead St., South Clarkson St.,
Dunbar St., and Cedar St. Tax parcel property identifiers used in this report are depicted on
Figure 2.

In November 2010, H&H conducted soil vapor sampling at the site to assess the potential for soil
vapor concerns from ground water impacts identified in the far northeastern portion of the site
along West Morehead St. H&H collected soil vapor samples from eight locations on the
property. The locations of the soil vapor samples, labeled VMP-1 through VMP-8, are indicated
in Figure 2.

The results of the November 2010 soil vapor sampling indicated that four of the eight soil vapor
samples (VMP-1, VMP-2, VMP-3, and VMP-6) contained compound concentrations above the
North Carolina Department of Environment and Natural Resources (DENR) Inactive Hazardous
Sites Branch (IHSB) Residential Soil Gas Screening Concentrations (SGSCs). Of these four soil
vapor samples, two sample locations (VMP-1 and VMP-2) contained concentrations above the
IHSB Industrial/Commercial SGSCs. VMP-1, VMP-2, and VMP-3 are located in the southeast
portion of the site on parcels 07314105 and 07314201, and VMP-6 is located in the central
portion of the site on parcel 07325501. In VMP-1, VMP-2, and VMP-3, the chlorinated solvents
tetrachloroethene (PCE), trichloroethene (TCE) and/or chloroform were detected above the
SGSCs. In VMP-6, 1,2,4-trimethylbenzene (1,2,4-TMB) and 1,3,5-trimethlybenzene (1,3,5-

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TMB) were detected above the SGSCs. The November 2010 soil vapor results are summarized
in Table 1.

The results of the soil vapor sampling were submitted to DENR in a Soil Vapor Assessment
Report dated January 20, 2011. Based upon their review of the soil vapor data, the DENR
Brownfields Section provided a preliminary indication that land use controls for potential future
buildings on parcels 07314105, 07314201, 07325501, 07325601, and 07325602 might be
needed. As such, to further refine the area where land use controls for future buildings might be
warranted, H&H conducted additional soil vapor sampling at the site on February 16 and 17,
2011. Prior to the sampling event, H&H submitted proposed soil vapor sampling locations to the
DENR Brownfields Section, and DENR approved the locations of the additional soil vapor
sampling points in an e-mail dated February 4, 2011.

The results of the recent February 2011 soil vapor sampling indicate that land use controls for
potential future buildings on parcels 07325501, 07325601, and 07325602 located in the central
portion of the site are not warranted. Based upon the results of the previous sampling conducted
in November 2010 which indicated chlorinated solvents above SGSCs, land use controls for
future buildings appear warranted for parcels 07314201 and 07314105 located in the
southeastern portion of the site.

The methods and results of the additional soil vapor sampling conducted in February 2011 are
discussed in detail in the following section.

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2.0 Soil Vapor Assessment
H&H conducted the soil vapor sampling on February 16 and 17, 2011. H&H collected soil
vapor samples from five locations, three on parcel 07325501 and two on parcel 07325602. The
locations of the soil vapor samples are indicated in Figure 2 and are summarized below:
• Three soil vapor samples (VMP-9, VMP-10, and VMP-11) were collected from parcel
07325501. VMP-9 was installed adjacent to previous soil vapor sample VMP-6 to
confirm the previous detections in this location. VMP-10 and VMP-11 were installed in
the southern and western portion of parcel 07325501 to provide soil vapor coverage over
a greater area of this parcel.

• Two soil vapor samples (VMP-12 and VMP-13) were collected from parcel 07325602.
VMP-12 was installed in the southern extent of the parcel, and VMP-13 was installed
adjacent to West Morehead St. as requested by DENR to further evaluate potential soil
vapor impacts from off-site sources.

2.1 Soil Vapor Sampling Methods

The soil vapor probes were installed on February 16, 2011. As no structures are present on the
property, H&H collected deeper soil vapor samples at a depth of 6 ft. This interval was selected
based upon a review of vapor intrusion guidance which indicates that at depths below 5 ft,
potential atmospheric influences will be negligible.

The soil vapor points were installed using a direct push technology (DPT) rig. The samples were
collected with the Geoprobe Post Run Tubing (PRT) System. Initially, the DPT rods were
advanced to the desired sampling depth of 6 feet bgs. Then, tubing attached to a dedicated 6-
inch long stainless steel screen was placed within the DPT rods. Once the implant was placed at

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the base of the borehole, it was rotated and attached to the anchor point located at the base of the
DPT driving tool. As the DPT rods were removed from the borehole, the implant and associated
tubing remained anchored at the bottom of the hole. Sand pack was then placed in the annular
space between the borehole and screen interval, and the remaining annular space of the screen
was sealed to ground surface using hydrated bentonite to minimize the potential for short
circuiting of vapors in the borehole and at the ground surface. The probe was then completed at
the surface with a valved sample port connected to Teflon® tubing. After allowing the bentonite
slurry to set for a minimum of 24 hours, H&H personnel collected vapor samples from each
VMP on February 17, 2011.

Prior to sampling, a leak check was conducted at each vapor monitoring point by constructing a
shroud around the sampling point and saturating the air within the shroud with helium gas.
Using a syringe, a sample was collected from the gas in the shroud into a Tedlar® bag and
analyzed for helium concentrations using a helium gas detector to verify that the air in the shroud
was saturated with helium gas. Then, vapor from the vapor monitoring point was purged and
sampled outside of the shroud into a separate Tedlar® bag and analyzed using the helium gas
detector to ensure that helium concentrations were less than 10% of the helium concentrations in
the shroud.

Following a successful leak check, a laboratory supplied 6-liter Summa canister was connected
to a flow regulator which was set to limit the vapor intake rate to approximately 0.75 liter per
hour for a total sample duration of 8 hours. The flow regulator was then connected to the VMP
tubing using a ferrule to form an air-tight seal and the Summa canister’s air intake valve was
then opened to begin collection of the soil vapor sample. Following completion of the sampling,
the soil vapor points were removed and the borings were abandoned.

Upon completion of the soil vapor sampling, the Summa canisters were shipped under standard
chain-of-custody procedures to Con-Test Analytical Laboratory in East Longmeadow, MA for
analysis of VOCs by EPA Method TO-15.

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2.2 Soil Vapor Results

The results of the soil vapor sample analyses are summarized along with the previous soil vapor
data in Table 1. The laboratory analytical data sheets are provided in Appendix A. The
concentrations of compounds detected in the soil vapor samples were compared to the DENR
IHSB Residential and Industrial/Commercial SGSCs.

As indicated in Table 1, several compounds were detected in the samples collected on February
17, 2011 including benzene, carbon disulfide, and toluene. Low concentrations of TCE and PCE
were detected in sample VMP-12 which is located in the southeastern portion of parcel
07325602, and low concentrations of PCE were detected in samples VMP-9 and VMP-10
located on parcel 07325501. However, none of the soil vapor samples contained compound
concentrations above the IHSB Residential or Commercial SGSCs. 1,2,4-TMB and 1,3,5-TMB
were detected in sample VMP-9 located adjacent to previous sample VMP-6; however, the
concentrations in VMP-9 were lower than those detected previously in VMP-6 and were not
above SGSCs.

Table 1
Summary of Soil Vapor Analytical Detections
18-Acre Beazer Property
Charlotte, NC
Hart & Hickman Project No. BEZ-002
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Table 1 (Page 1 of 1)
Hart & Hickman, PC
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VMP-1 11/08/10 TO-15 <24 <3.2 <2.9 48 <2.6 63 <2.1 <3.4 7.8 4.9 6.8 510 79 <19 <3.6 <4.3 <4.9 <4.1 <3.5 <2.5 <6.9 <17 <4.3 320 <3.8 <5.5 14000 16 <7.7 <4.9 <4.9 <2.6 <8.7 <4.3
VMP-2 11/08/10 TO-15 13 B 1.4 1.6 68 <0.53 9.0 <0.41 <0.69 2.2 <0.81 <0.79 3.4 <0.79 <3.8 <0.72 <0.87 <0.98 4.1 2.2 <0.49 1.8 <3.4 <0.85 72 3.9 <1.1 3100 3.2 <1.5 <0.98 <0.98 <0.51 <1.7 1.3
VMP-3 11/08/10 TO-15 13 B 0.82 1.7 3.8 <0.26 2.3 <0.21 <0.34 2.5 <0.40 <0.40 4.2 <0.40 3.4 B <0.36 <0.43 <0.49 <0.41 <0.35 <0.25 1.0 B <1.7 <0.43 42 0.54 <0.55 560 17 <0.77 <0.49 <0.49 <0.26 <0.87 <0.43
VMP-4 11/08/10 TO-15 15 B 2.2 1.7 100 <0.53 <0.98 <0.41 <0.69 2.5 <0.81 <0.79 <0.79 <0.79 <3.8 <0.72 1.6 <0.98 3.8 2.2 <0.49 <1.4 <3.4 <0.85 1.4 12 <1.1 <1.1 3.2 <1.5 <0.98 <0.98 <0.51 3.0 2.2
VMP-5 11/08/10 TO-15 15 B 3.4 1.3 100 <0.53 3.3 <0.41 <0.69 2.7 <0.81 <0.79 <0.79 <0.79 <3.8 <0.72 1.1 <0.98 1.0 2.6 <0.49 <1.4 <3.4 <0.85 1.4 2.8 1.4 <1.1 6.0 <1.5 <0.98 <0.98 <0.51 <1.7 3.2
VMP-6 11/08/10 TO-15 <4.8 27 2.5 170 <0.53 3.0 <0.41 23 2.4 2.7 <0.79 <0.79 <0.79 <3.8 <0.72 18 <0.98 24 41 3.7 4.7 <3.4 9.2 11 48 3.8 2.6 30 <1.5 29 23 <0.51 28 25
VMP-7 11/08/10 TO-15 <2.4 17 1.2 46 <0.26 0.77 <0.21 4.6 3.3 0.75 <0.40 <0.40 <0.40 <1.9 1.4 2.7 0.8 0.75 9.3 <0.25 1.1 <1.7 6.1 7.4 19 1.7 4.4 24 <0.77 2.6 1.1 <0.26 6.7 6.8
VMP-8 11/08/10 TO-15 <4.8 18 1.3 47 <0.53 <0.98 <0.41 4.6 3.0 <0.81 <0.79 <0.79 <0.79 <3.8 <0.20 2.7 <0.98 0.84 9.1 <0.49 <1.4 <3.4 6.1 7.5 20 1.6 4.5 24 <1.5 2.8 1.1 <0.51 6.8 7.0
VMP-9***02/17/11 TO-15 57 4.2 6.4 5.1 <0.40 2.3 0.91 1.7 3.2 B <0.61 <0.59 <0.59 <0.59 26 <0.54 4.9 0.91 3.0 16 2.3 15 140 1.6 2.4 2,300 1.5 <0.81 16 LH 1.2 1.8 <0.74 <0.38 5.6 1.8
VMP-10 02/17/11 TO-15 <1.4 19 21 27 1.0 <0.73 1.2 23 3.8 B 1.00 <0.59 <0.59 <0.59 21 5.1 3.1 1.90 34 77 11 7.9 720 2.7 2.7 110 <0.82 <0.81 4.0 LH <1.1 1.7 0.93 0.40 5.8 5.2
VMP-11 02/17/11 TO-15 16 5.3 2.5 3.5 <0.53 <0.98 0.88 <0.69 2.9 B <0.81 <0.79 <0.79 <0.79 5.0 <0.72 2.2 <0.98 <0.82 3.1 <0.49 1.6 39 1.5 <1.4 1,500 <1.1 <1.1 9.9 <1.5 <0.98 <0.98 0.62 2.6 <0.87
VMP-12 02/17/11 TO-15 22 1.6 2.3 7.3 <0.53 1.8 <0.41 <0.69 4.0 B <0.81 <0.79 <0.79 <0.79 9.2 <0.72 <0.87 <0.98 0.87 5.2 1.8 2.5 J 97 <0.85 4.30 27 <1.1 70 18 LH <1.5 <0.98 <0.98 <0.51 1.1 J <0.87
VMP-13 02/17/11 TO-15 58 1.6 8.8 5.1 <0.79 <1.5 <0.62 <1.0 8.4 B <1.2 <1.2 <1.2 <1.2 23 <1.1 <1.3 <1.5 1.60 7.2 6.4 15 66 <1.3 <2.0 38 <1.6 <1.6 2.1 2.3 B <1.5 <1.5 <0.77 1.9 J <1.3
64,000 31 10,400 1,460 NE 11 188 NE 420 150 420 126*126 NE NE 97 NE NE 1,460 NE 520 NE 2,000 41 10,400 10,400 120 120 260,000 14.6 14.6**16 1,460 1,460
280,000 160 44,000 6,200 NE 53 780 NE 1,760 770 1,760 520*520 NE NE 490 NE NE 6,200 NE 2,600 NE 8,800 210 44,000 44,000 610 6,200 62,000 62 62**280 6,200 6,200
Notes:
*** = VMP-9 collected in the same approximate location as VMP-6
** = 1,2,4-trimethylbenzene used as a surrogate for 1,3,5-trimethylbenzene
2. Bold indicates concentration exceeds DENR IHSB Residential Soil Gas Screening Levels
4. NE = Not Established, µg/m3 = micrograms per cubic meter , B = analyte is found in the associated blank as well as in the sample.
LH = Laboratory fortified blank/controil sample is outside of control limits; reported value is likely to be on the high side.
J = Detected but below the reporting limit. Result is an estimated concentration.
* = trans-1,2-dichlorothene used as a surrogate for cis-1,2-dichloroethene
µg/m3
IHSB Industrial/Commercial Soil Gas Screening
Concentration
3. Bold and underlined indicates concentration exceeds DENR IHSB Industrial/Commercial Soil Gas Screening Levels
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IHSB Residential Soil Gas Screening
Concentration
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1. Only those analytes detected in at least one sample are shown in this table
SITE
0 2000 4000
APPROXIMATE
SCALE IN FEET
N
U.S.G.S. QUADRANGLE MAP
QUADRANGLE
7.5 MINUTE SERIES (TOPOGRAPHIC)
TITLE
PROJECT
SITE LOCATION MAP
18-ACRE BEAZER PROPERTY
CHARLOTTE, NORTH CAROLINA
DATE:
JOB NO:
REVISION NO:
FIGURE:
12-6-10 0
1BEZ-002
CHARLOTTE EAST, NC 1991
Hart & Hickman, PC
Appendix A
Laboratory Analytical Data

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