Andale_VI Evaluation - Future Bldg Pad-OCR

€NV IRON
August 23, 2011
Via Electronic Mail
Kevin Lew
Andale, Inc.
Re: Vapor Intrusion Evaluation -Future Building Pad
Andale, Inc.
Forest City, North Carolina
At your request, ENVIRON International Corporation (ENVIRON) has prepared this evaluation of
the potential for vapor intrusion to represent a significant exposure scenario within the final
footprint of the proposed Building 2 and Building 3 (i.e., the "future building pad") on the
northern portion of the Andale, Inc. property located at 1181 Old Caroleen Road in Forest City,
North Carolina.
Pertinent Site Background
Historical information regarding the site indicate that prior to 1966 the site was comprised of
wooded and agricultural land, and one or more residences may have been located on the
western or southern portions of the site, along Old Caroleen Road and/or Low Bridge Road. In
1966, the northern portion of the site was developed by Burlington Industries for use as a
textile manufacturing facility. Burlington ceased operations at the site in March 1999, and the
property was subsequently acquired by Rutherford County in 2002. Beginning in 2003,
Rutherford County leased the facility on the northern portion of the site to Mako for use in
fiberglass boat manufacturing. Mako ceased operations at the site in 2009, and the property
was vacated until its acquisition and development by Andale in 2010.
Multiple environmental site assessments and investigations have been conducted at the site
since the early 1990s (Summary of Investigations Report [ENVIRON, 2011]). Notably, soil and
groundwater have been sampled from locations adjacent to and within the footprint of the
future building pad on the northern portion of the property (Figure 1). During these sampling
events, no volatile organic compounds (VOCs) were identified at concentrations that exceeded
the USEPA Regional Screening Level for Industrial Soils (Industrial RSLs) or the North Carolina
lSA NCAC 2L .0202 (NC 2L) standards, respectively.
Since site development commenced in November 2010, ENVIRON has conducted a subsurface
soil investigation at the former Mako building and WWTP area. In addition, a soil vapor
investigation was conducted underneath the slab of the former Mako building and from two
adjacent former storage tank areas where focused soil remediation was conducted (one AST
and one UST). Additionally, ENVIRON installed two temporary monitoring wells in the former
UST area and collected groundwater samples from those two wells. The results of the sampling
activities, conducted in April through July, 2011, indicated the presence of VOCs in the soil
vapor and groundwater samples.
1600 Parkwood Circle, Suite 310, Atlanta, GA 30339 www.environcorp.com
Tel: [phone] Fax: [phone]
Vapor Intrusion Evaluation -Future Building Pad
Forest City, North Carolina
Figure 2 -Historical Soil Sampling Locations
Figure 3 -Historical Groundwater Sampling Locations
Figure 4 -Historical Soil Vapor Sampling Locations
References:
Andale, Inc.
Page -5 -
American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (ASH RAE).
2007. Ventilation for Acceptable Indoor Air Quality. ANSl/ASHRAE Standard 62.1-2007. Table
6-1, pp.13-15. ASHRAE, 1791 Tullie Circle NE, Atlanta, GA 30329.
USEPA, 2002. "Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from
Groundwater and Soils", United States Environmental Protection Agency OSWER EPA 530-0-02-
004. November .
•
1600 Parkwood Circle, Suite 310, Atlanta, GA 30339 www.environcorp.com
Tel: [phone] Fax: [phone]
ach Scenario (1/hr)
ASHRAE minimum for 0.83 computer spaces
Measured ventilation
rate {17 ach) with 20% 3.4
fresh air
Maximum ventilation
rate (84 ach) with 20% 16.8
fresh air
Table 1 -Summary of Subslab Concentrations Necessary to Result in
Potentially Significant Indoor Air Concentrations
Forest City, North Carolina
IHSBAcceptable Indoor Air Subslab Cone to Result in IA Attenuation Constituent Criterion Cones equal to IHSB Criteria
Factor (ug/m3) (ug/m3)
1,3-butadiene 4.41E-06 4.lOE-01 9.30E+04
Tetrachloroethene 4.41E-06 2.lOE+OO 4.76E+05
Trichloroethene 4.41E-06 6.lOE+OO 1.38E+06
1,2,4-trimethylbenzene 4.41E-06 6.20E+OO 1.41E+06
1,3-butadiene 1.08E-06 4.lOE-01 3.81E+05
Tetrachloroethene 1.08E-06 2.lOE+OO 1.95E+06
Trichloroethene 1.08E-06 6.lOE+OO 5.67E+06
1,2,4-trimethylbenzene l.08E-06 6.20E+OO 5.76E+06
1,3-butadiene 2.18E-07 4.lOE-01 1.88E+06
Tetrachloroethene 2.18E-07 2.lOE+OO 9.64E+06
Trichloroethene 2.18E-07 6.lOE+OO 2.80E+07
1,2,4-trimethylbenzene 2.18E-07 6.20E+OO 2.85E+07
Attenuation factors are calcualted as the ratio of Q50;1 over Oiiuilding using the planned building dimensions and the indicated air exchange rate.
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Max
Detect in
Subslab
(ug/m3)
l.10E+02
2.00E+03
5.70E+03
1.70E+04
1.10E+02
5.70E+03
1.70E+04
2.00E+03
1.10E+02
5.70E+03
l.70E+04
2.00E+03
ENVIRON
Table 2 -Cancer Risk and HI Estimates from Potential Vapor Intrusion from Soil Gas
Andale, Inc. Site
Forest City, North Carolina
~nalyte Max Frequency Units Vapor Intrusion Vapor Intrusion
Detect of Detects Cancer Risk Hazard Quotient
Acetone 2,800 11/16 ug/m3 NA 7E-97
Benzene 33 9/16 ug/m3 2E-139 2E-135
1,3-Butadiene 110 3/16 ug/m3 lE-51 6E-50
2-Butanone (MEK) 42 7/16 ug/m3 NA 9E-149
Carbon disulfide 17 7/16 ug/m3 NA 4E-117
Chloroform 15 7/16 ug/m3 2E-119 NA
Dichlorodifluoromethane 560 13/16 ug/m3 NA 7E-177
1,1-Dichloroethane 4.5 2/16 ug/m3 NA lE-161
1,1-Dichloroethene 9.2 3/16 ug/m3 NA 6E-134
is-1,2-Dich loroethene 18 3/16 ug/m3 NA 2E-161
1,4-Dioxane 17 1/16 ug/m3 NA NA
Ethyl benzene 6.4 1/16 ug/m3 NA 4E-160
n-Hexane 20 3/16 ug/m3 NA 6E-64
2-Hexanone 12 4/16 ug/m3 NA NA
2,2,4-Trimethylpentane 2.9 1/16 ug/m3 NA NA
lsopropyl alcohol 73 7/16 ug/m3 NA NA
4-Methyl-2-pentanone (MIBK) 38 2/16 ug/m3 NA 9E-160
Methylene chloride 3.6 1/16 ug/m3 5E-125 lE-121
Styrene 9.8 6/16 ug/m3 NA 2E-168
tert-Butyl alcohol 14 1/16 ug/m3 NA NA
Tetrachloroethene 2,000 11/16 ug/m3 lE-166 lE-163
Toluene 18 10/16 ug/m3 NA 3E-138
1,1,1-Trichloroethane 92 7/16 ug/m3 NA 2E-153
Trichloroethene 5,700 7/16 ug/m3 7E-151 5E-148
Trichlorofluoromethane 490 13/16 ug/m3 NA 4E-137
1, 1,2-T rich loro-1, 2, 2-trifluoroetha ne 740 4/16 ug/m3 NA lE-153
1,2,4-T rimethylbenzene 17,000 3/19 ug/m3 NA lE-190
m-Xylene & p-Xylene 4.9 5/16 ug/m3 NA 2E-155
o-Xylene 1.8 2/16 ug/m3 NA lE-138
Sum: lE-51 6E-50
Notes:
ug/m3 Micrograms per cubic meter
NA Not applicable, either because the chemical does not have toxicity of the applicable type or the chemical is not in
USEPA's chemical list.
Vapor intrusion cancer risk and noncancer HQ estimates were calculated for the maximum detected concentrations using
the default parameters in USEPA's SG-ADV spreadsheets Version 3.1; 02/04, except as follows:
• The soil gas sampling depth below grade (LF) was set to 15 cm, the approximate thickness of the existing slab, to
represent that the soil gas is immediately below the slab.
•The average soil temperature (T5) was set to 20 Celsius.
•The thickness of soil stratum A was set to 15 cm so only one soil type would be used, and the stratum A SCS soil type
was set to loamy sand (LS), the soil type at the site, to estimate soil properties.
•The enclosed space length (L8) and width (W8) were set to 168 meters by 168 meters, respectively, the area of the
building under consideration.
• The enclosed space height (H8) is 914 cm or 30 feet.
• The indoor air exchange rate (ER) was set to 0.83/hr, the ASH RAE-recommended minimum breathing zone air exchange
rate for computer rooms (non-printing).
• The average vapor flow rate into the building (Q,0;1) was left blank to allow the spreadsheet to calculate the flow rate.
• The exposure frequency (EF) was set to 83.3 to incorporate the industrial default value of 250 days/year and an
exposure time of 8 hours per day (i.e., 250*8/24 = 83.3), consistent with USEPA's RAGS Part F (2009).
•The soil-building pressure differential (~P) was set to -249 g/cm/s2 (-0.1 inches of water) to reflect the fact that the
ventilation system operates at a positive pressure of at least 0.1 inches of water.
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