20077_Crown Honda II_DM_20201123

DECISION MEMORANDUM
DATE: October 29, 2020
FROM: Kathleen Markey/Sharon Eckard
TO: BF Assessment File
RE: Crown Honda II
1098, 1900, and 2000 Novus Lane
Chapel Hill, Orange County
Brownfields Project Number 20077-16-068
Based on the following information, it has been determined that the above referenced
site, whose intended use is for no uses other than high density residential and associated
parking, and subject to DEQ's prior written approval, other commercial uses, can be
made suitable for such uses.
Introduction:
The Brownfields Property is comprised of three parcels totaling 6.56 acres and is located
between Fordham Boulevard and Legion Road in Chapel Hill, Orange County.
According to the Orange County Tax Administration Office, Tracts 1, 2, and 3 are
assigned with the following Tax ID numbers: 9799-36-6631, 9799-36-7662, and 9799-
46-1235. The Brownfields Property Application for this property reported the address of
the property as 1730 Fordham Boulevard; however, according to the Orange County Tax
Administration Office, the tracts have been assigned different addresses. Tract 1 has been
assigned 2000 Novus Lane, Tract 2 has not been assigned an address, and Tract 3 has
been assigned 1098, 1900, and 2000 Novus Lane. Tracts 1 and 2 have historically been
developed as an automotive dealership (Hendrick Automotive Group aka Hendrick) that
conducted service and repairs, and a road providing access to Tract 1 and Tract 3,
respectively. Tract 3 was historically a residential property, but was recently used as a
parking lot for the automotive dealership. The Prospective Developer (PD) is LG Chapel
Hill Apartments, LLC.
Redevelopment Plans:
The site redevelopment plans included demolishing the existing buildings associated with
the former Hendrick automotive operations on primarily Tract 1. Demolition activities
began in April 2018. Mass grading of the Brownfields Property began in May 2018 with
vertical building construction commencing in August 2018. The initial building to be
constructed was Building 2, a four-story residential apartment building with ground floor
podium parking located on the southeastern portion of the Brownfields Property (Tract
3). The construction of Building 1, a five -story residential apartment building with a
central parking garage, is nearing completion. Both structures offer a total of
approximately 300 units. The parking deck is above grade and is located adjacent to the
Building 1 on Tracts 1 and 2.
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In light of the historical automotive uses on Tract 1 of the Brownfields Property and
existing environmental data, as part of Brownfields Agreement negotiations, the pre-
emptive installation of a vapor intrusion mitigation system (VIMS) was required for the
construction of the apartment complex on both Tract 1 and Tract 3. Building 1, which is
constructed on Tract 1, has an active vapor mitigation system, and Building 2, which is
constructed on Tract 3, has a passive barrier vapor mitigation system with the capacity to
switch to active operation.
It was agreed that clean, milled asphalt material from the demolition activities could be
reused at the Brownfields Property under certain conditions as noted in the approved Soil
Export, Soil Stockpiling and Asphalt Reuse Plan (McAdams, July 2, 2018).
Final grade and landscaped area sampling will also be performed at the Brownfields
Property.
Site History:
Based on historical knowledge and review of the Sanborn Maps, the Brownfields
Property was generally woodland and agricultural fields from at least 1938. From 1938-
1964, it was used for agricultural purposes with a residential structure constructed on the
southeastern portion of the Brownfields Property during that time. Agricultural purposes
continued until 1980, when the auto sales, service and repair facility was constructed
primarily on Tract 1, with access to the site on Tract 2. During that time, above ground
storage tanks (AST), several fuel underground storage tanks (UST), an oil water separator
(OWS), waste oil UST, and hydraulic lifts were in use at the Brownfields Property.
The Brownfields Property has been assigned various DEQ UST Section Incident
Numbers. Previous environmental assessment activities conducted at the Brownfields
Property identified petroleum hydrocarbons and chlorinated solvents associated with past
use as an automotive dealership with maintenance and repair facilities. Tract 1 was
assigned:
1) AST Incident Number 87983 for a 500-gallon AST that stored waste
antifreeze; documentation of the regulatory outcome for this incident number was not
readily available, but it appears to not be an active incident, and available data does not
suggest that there was an appreciable release from this AST.
2) UST Incident Number 26611 for an oil/water separator UST, which was the
subject of a No Further Action (NFA) letter from the DWM UST Section on October 4,
2006 based on petroleum soil contamination not exceeding residential standards and no
identified impact to groundwater;
3) UST Incident No. 26482 for a 3,000-gallon waste oil UST and a 10,000-gallon
gasoline UST that were removed from the south side of the automotive building in 1994.
The incident was reported to be closed on August 16, 1994; and
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4) LUST Incident No. 19316 for a 2,000-gallon waste oil UST and a 1,000-gallon
new oil UST that were removed from the south side of the automotive building in March
1998 for which NCDENR issued an NFA on November 19, 1998,
In addition, there were twenty in -ground hydraulic lifts and an oil -water separator in
operation in the automotive facility. Excavation within the auto service area had been
completed in 2005 and was enlarged in 2016 with a final excavation dimensions of 8.5 ft
x 11 ft x 12.5 ft deep. The excavation was backfilled with quarried stone.
The hydraulic lifts and the oil water separator were removed in April 2018 in accordance
with an Environmental Management Plan (EMP) approved by DEQ on December 12,
2017. Evidence of releases were identified in soil and perched groundwater. A total of
800 tons of contaminated soil was excavated from these areas and sent for offsite disposal
to Earth-tec in Sanford, NC. Confirmation soil sampling identified the presence of low
concentrations of metals, as well as tetrachloroethylene (PCE) and trichloroethylene
(TCE) and various other petroleum constituents.
During construction activities, a release from a construction services diesel AST in
January 2019 near the northeastern corner of the Brownfields Property, reportedly during
a fuel theft, resulted in release of diesel fuel to the stormwater detention basin. A total of
about 71 tons of diesel -impacted soil was removed from an excavation area of about 16 ft
x 12 ft x 0.5 ft deep, and transported offsite for disposal at Earth-tec in Sanford, NC.
Confirmation soil samples indicated that total petroleum hydrocarbons as diesel range
organics (TPH-DRO) are present in excess of DWM UST Section Action Levels of 100
milligrams per kilogram (mg/kg) in this area of Tract 1.
Tract 1 of the Brownfields Property is associated with the NCDWM Inactive Hazardous
Site Branch (IHSB) Number NONCD0001570. Due to the presence of chlorinated
solvents identified in soil samples taken in the location of the in -ground hydraulic lifts,
IHSB handled assessment activities for solvent impacts on site. IHSB issued a No Further
Action letter on March 10, 2017 to Hendrick Automotive Group after reviewing
information provided to IHSB.
Tract 3 was used for residential purposes until 1993. In 2002, the residential structures
were removed, and the site was paved for automobile parking, which was expanded from
the existing automotive lots onto Tract 3. By 2010, Tract 3 was vacant and unoccupied.
A 250-gallon home heating oil UST, believed to be associated with the former residence,
was encountered during grading activities in May 2019; the UST was removed and about
40 tons of petroleum -impacted soil was excavated and transported offsite to Earth-Tec in
Sanford, NC. Confirmatory soil samples indicated impact remained; however, final grade
of the Brownfields Property in this area was cut down below the base of the UST
excavation.
After the construction of Building 2, the PD conducted performance testing of the VIMS
on October 3, 2019, including the collection of pressure measurements and sub -slab
vapor samples. The construction of Building 1 is ongoing; performance testing of the
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VIMS at Building 1 occurred on June 1, 2020, which also included the collection of
several sub -slab vapor samples with subsequent pressure testing. Several volatile organic
compounds (VOCs) were detected in these sub -slab samples, but at concentrations below
their applicable DWM residential vapor intrusion screening levels (VISLs).
Based on a Microsoft Teams call with Bruce Nicholson, Kelly Johnson, Kathleen
Markey, and Sharon Eckard of the Brownfields Program and the PD and its consultants
including Jeff Tyburski, and Matt Jenny of Geosyntec that took place on October 14,
2020, the Brownfields Program was informed that modifications to the vertical risers and
sub slab mechanical, electrical and plumbing retrofit penetrations of the slab and
underlying barrier and stone layers within Building 2 occurred during construction
without notice and observation by the professional engineer.
These modifications appear to be impacting the performance of the VIMS. The PD will
modify the post -construction performance issues prior to occupancy date; however,
because sub -slab data is not inconsistent with the reuse, public health should not be
impacted by these modifications. At the engineer's request, DEQ modified the land use
restriction (LUR) in the BFA related to the engineer's statement for the LUR update. The
PD has committed to installing additional fans and re -sampling to confirm that the
modifications are not adversely impacting indoor air quality within Building 2.
Potential Receptors:
Potential receptors are: construction workers, on -site workers, future residents, visitors,
animals and trespassers.
Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property: soil,
sub -slab vapor, soil gas, and groundwater at the Brownfields Property. DEQ relies on the
following data to base its conclusions regarding the subject property and its suitability for
its intended reuse.
Soil
Tract 1 soil samples results from the SB-series of soil borings obtained in 2016 (Withers
Ravenel) included TPH analyses using mobile laboratory UVF technology, which the
Brownfields Program does not accept. VOCs and semi -volatile organic compound
(SVOCs) analyses conducted on these samples did not detect these compounds in excess
of residential Preliminary Soil Remedial Goals (PSRGs).
On February 28, 2018, eight soil borings (TMW-1 through TMW-8) were advanced on
the Brownfields Property as temporary monitoring wells. An additional temporary
monitoring well, TMW-9 was installed on March 5, 2018. Soil from each boring was
screened for VOCs, SVOCs, and metals, and one soil sample from each of the monitoring
well borings, TMW-1 through TMW-6, were submitted for chemical analysis. Benzene
was detected in TMW-4 (5-9) at a concentration below its residential PSRG. No other
VOCs nor SVOCs were detected in these soil samples. Barium, lead and total chromium
were detected at concentrations below their respective residential PSRGs. Mercury was
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detected in TMW-3 (8-11) at a concentration below the residential PSRG. Silver was
detected in samples TMW-1 (1-5), TMW-2 (5-10), and TMW-4 (5-9) at concentrations
below residential PSRGs. Arsenic was detected at concentrations above residential
PSRGs in each of the soil borings ranging up to 6.4 mg/kg in sample TMW-6.
Seventeen test pits were excavated on Tract 3 to evaluate soil conditions. Soil samples
from TP-3, TP-6, TP-9, TP-11, and TP-13 were collected and submitted for chemical
analysis. VOCs were not detected in these soil samples. SVOCs detected in these soils
were limited to only two polynuclear aromatic hydrocarbons (PAHs), benzo(a)pyrene and
phenanthrene the sample from TP-11, and only B(a)P exceeded its residential PSRG of
0.11. Phenanthrene does not have an established screening level. As per metals analyses
in the test pit samples, only arsenic concentrations exceeded the residential PSRG of 0.68
mg/kg with a range of 1.1 mg/kg to 6.4 mg/kg.
Confirmatory soil samples from the oil water separator and hydraulic lift areas had only
arsenic concentrations exceeding its residential PSRG with a range of concentrations of
2.8 mg/kg to 5.7 mg/kg.
In addition, two confirmatory soil samples (FT -East and FT -South) from the diesel AST
release exceeded the UST Section Action Level of 100 mg/kg with a range in
concentration of 465 mg/kg to 1,270 mg/kg.
Groundwater
Groundwater contaminants detected at concentrations above the NC 2L groundwater
standards include: up to 4.1 micrograms per liter (µg/L) for bromodichloromethane, 1.2
µg/L for dibromochloromethane and 9.1 µg/L for tetrachloroethene (PCE), for sample
WS-1. The presence of bromodichloromethane and dibromochloromethane were
indicated in groundwater sample WS-1, which was a grab sample collected from within
the excavation area. PCE was detected in the grab sample from the water in the
excavation pit prior to soil removal during September 2016.
Most groundwater wells at the Brownfields Property with the exception of TMW-2 (Tract
1) and TMW-9 (Tract 3) were dry. Concentrations of acetone, methyl-tert-butyl ether
(MTBE), barium, total chromium, and lead were detected in either or both TMW-2 and
TMW-9, but not at concentrations that exceeded their respective 2L groundwater
standards nor the residential VISL.
Note: that the laboratory report for these groundwater samples erroneously attributes the
data from TMW-9 to well TMW-4 due to misreading the chain of custody form. This is
also further supported by the fact that TMW-4 was dry.
Surface Water
Surface water is not located on the site.
Soil Vapor
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Chlorinated solvents PCE and cis-1,2-dichloroethylene (cis-1,2-DCE), 4-Ethyltoluene,
and 2,2,4-Trimethylpentane were identified in soil vapor point SV-1 & SV-2 at
concentrations above laboratory detection limits, but below their respective residential
SGSLs.
Sub -Slab Vapor
Post -construction sub -slab vapor samples were collected on October 3, 2019 at three
locations coincident with the enclosed spaces on the ground floor of Building 2 as most
of the ground floor consists of podium parking. In addition to the three sub -slab samples,
one duplicate sample was also collected (SG-1 — SG-3) from below the slab at Building
2. SG-1, SG-2, SG-3, and DUP-1 had hits of 1,3-dichlorobenzene but there is no
screening level established for this contaminant. SG-1, SG-2, SG-3, and DUP-1 had hits
of ethanol but there is no screening level established for this contaminant. DUP-1 and
SG-3 had hits of 4-ethyltoluene but there is no screening level established for this
contaminant. SG-1 and DUP-1 had hits of trichlorofluoromethane, but there is no
screening level established for this contaminant.
Post -construction sub -slab vapor samples (SG-4 - SG-13) were collected on June 1, 2020
at Building 1. Several VOCs were detected, but none above their respective residential
VISLs.
Indoor Air
Indoor air data was not collected prior to the demolition of existing buildings and is not
deemed necessary based on available groundwater, soil gas, and sub -slab soil vapor data
combined with the redevelopment specifications to install either a passive or an active
vapor intrusion mitigation system in both buildings. Sub -slab vapor data collected to date
in the two new buildings do not indicate the need for indoor air sampling at this time.
Risk Calculations
Risk calculations were performed using the DWM Risk Calculator (December 2019
version). The risk evaluation procedures, equations, and default parameters used to
create the calculator follow the current USEPA risk assessment guidance.
The three tracts of the Brownfields Property were evaluated as two separate areas. The
two northernmost parcels (Tracts 1 and 2), the site of Building 1, and the southernmost
parcel (Tract 3), the site of Building 2, were evaluated separately. A separate risk
calculator was constructed for the post -construction sub -slab vapor sample date collected
under Building 1 to separate out the effect of the pre -construction soil vapor data near the
former automotive service building on Tract 1, and the post -construction sub -slab vapor
data on Building 1. The risk calculations indicated the following based on available data,
including the following media: groundwater, confirmatory soil, soil gas samples, and
post -construction sub -slab vapor samples (only Building 1):
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Northern Parcel (Tract 1 & Tract 2)
Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 20077-16-068
Exposure Unit ID: Tracts 1&2:TMW-2,WS-1,Fr-series, SV-series
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carciinnogenic
sk
Hazard Index
Ri sk exceeded?
Resident
Soil
9.3E-06
5.7E+00
YES
Groundwater Use*
7.9E-05
8.7E-01
NO
Non -Residential Worker
Soil
2.1E-06
1.0E+00
YES
Groundwater Use*
1.8E-05
1.9E-01
NO
Construction Worker
Soil
3.5E-07
1.3E+01
YES
Recreator/Trespasser
Soil
5.2E-06
1.2E+00
YES
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
sk
Hazard Index
Riskexceeded?
Resident
Groundwater to Indoor Air
1.8E-05
4.6E-01
NO
Soil Gas to Indoor Air
2.5E-05
8.7E-01
NO
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
4.1E-06
1.1E-01
NO
Soil Gas to Indoor Air
1.9E-06
6.9E-02
NO
Indoor Air
t NC
NC
NC
With regard to Tracts 1 & 2, based on available data, exposure risks for any scenario do
not exceed an acceptable cancer risk; however, all soil pathways exceed the threshold
noncancer hazard index of 1 for direct contact in residential, nonresidential, construction
worker and recreator exposure scenarios. This is largely attributed to a residual total
petroleum hydrocarbon value in the FT -series samples at a depth of 0.5 feet that were a
result of an accidental fuel release in January 2019 in the most northeastern corner of
Tract 2. A total of 70.91 tons of petroleum -impacted soil were excavated from this area
and transported to Earth-Tec for off -site disposal. This area is located under the roadway
of Tract 2 and therefore does not continue to pose an exposure risk.
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Although there are no exceedances of acceptable incremental carcinogenic risk, nor the
threshold noncancer risk hazard index of 1, the residential groundwater to indoor air and
the residential soil gas to indoor air calculators indicate that the hazard indices for these
two exposure scenarios is 0.46 and 0.87, respectively. It is important to note that the soil
vapor sample results in this risk calculator are from exterior soil vapor samples, SV-1 and
SV-2, and are not from sub -slab samples collected under the former automotive services
building on Tract 1 nor from post -construction sub -slab vapor sampling at Building 1.
Post -construction sub -slab sampling for Building 1 occurred on June 1, 2020, and those
sample results were used to prepare a separate risk calculator looking only at the post -
construction sub -slab data as noted below.
Northern Parcel (Building 1 — Post -Construction Sub -Slab Vapor Only)
Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 22007-16-068
Ex sure Unit ID: Building 1 -Post Construction Sub -Slab Vapor SG-4-SG-13
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carcinogenic
Hazard Index
Pi sk exceeded?
Resident
Soil
NC
NC
NC
Groundwater Use*
NC
NC
NC
Non -Residential Worker
Soil
NC
NC
NC
Groundwater Use*
NC
NC
NC
Construction Worker
Soil
NC
NC
NC
Recreator/Trespasser
Soil
NC
NC
NC
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
1.1E-06
2.6E-01
NO
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
NC
NC
NC
Soil Gas to Indoor Air
8.2E-08
2.0E-02
NO
Indoor Air
0.0E+00
0.0E+00
NO
As noted above, the soil gas to indoor air calculated risk values do not exceed either an
acceptable carcinogenic risk range nor the threshold hazard index of 1. An active VIMS
was installed at this location.
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Southern Parcel (Tract 3)
Risk for Individual Pathways
Version Date: December 2019
Basis: November 2019 EPA RSL Table
Site ID: 20077-16-068
Ex sure Unit ID: Tract 3:TP-11, TMW-9,Post-construction SubSlabVa r (SG-1 to SG-3)
DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor
Pathway
Carciinnogenic
sk
Hazard Index
Risk exceeded?
Resident
Soil
1.1E-05
2.0E-01
NO
Groundwater Use*
0.0E+00
6.4E-05
NO
Non -Residential Worker
Soil
2.2E-06
1.5E-02
NO
Groundwater Use*
0.0E+00
1.1E-05
NO
Construction Worker
Soil
3.7E-07
1.7E-01
NO
Recreator/Trespasser
Soil
6.2E-06
1.1E-01
NO
Surface Water*
NC
NC
NC
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
sk
Hazard Index
Riskexceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
2.2E-06
5.5E-02
NO
Indoor Air
NC
NC
NC
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
1.7E-07
4.4E-03
NO
Indoor Air
t NC
NC
NC
Acceptable environmental risk ranges for carcinogenic risk and acceptable noncancer
hazard indices are calculated for all exposure pathways and for all media sampled, which
includes soil, groundwater, and post -construction sub -slab vapor samples for Building 2,
which was constructed on Tract 3. Construction of Building 2 included the installation of
a passive vapor barrier as a pre-emptive vapor mitigation measure.
Required Land Use Restrictions:
The land use restrictions will include the standard prohibitions on use of groundwater,
soil disturbance, restrictions on bringing soil onto or exporting from the Brownfields
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Property, addressing vapor intrusion, allowance for well abandonment, notice, access and
land use restriction update restrictions. Building 1 that is constructed over the former
automotive service shop was constructed with an active VIMS installed, and Building 2
that is constructed over largely undeveloped or former residential property was
constructed with a passive VIMS. Post -installation unobserved modifications of the
VIMS at Building 1 requires the modification of our standard language in the LURU
LUR at the request of the design engineer; otherwise the VIMS installation and
performance is in accordance and in compliance with the provisions of the standard VI
LUR in the BFA's subparagraph 151.
Based on the site -specific data provided to the Brownfield program, the site reuse is
suitable for the site as long as the agreed upon land use restrictions in the BFA are abided
by.
Property Management Unit:
As of the writing of this Decision Memo, the PD has not yet provided the Brownfields
Program with the required report on the performance testing of the VIMS at Building 1.
Additional monitoring requirements may be required based on a review of that document.
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