HomeMy WebLinkAboutDilworth Auto Decision Memorandum 202211181
Dilworth Automotive/24051-20-060/20221118
DECISION MEMORANDUM
DATE: November 18, 2022
FROM: Bill Schmithorst
TO: BF Assessment File
RE: Dilworth Auto Service
1714 South Boulevard
Charlotte, Mecklenburg County
BF# 24051-20-060
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, industrial,
office, parking, retail, warehousing, entertainment, hotel, restaurant, brewery and food
production facility, distillery, open space, recreational, institutional, and with prior
written DEQ approval, other commercial uses, can be made suitable for such uses.
Introduction:
The Prospective Developer is South End Property Owning Sub, LLC a limited liability
company headquartered at 4064 Colony Road, Suite 310, Charlotte, NC 28211. The
Brownfields Property consists of one parcel of land totaling approximately 1.28 acres
located at 1714 South Boulevard (Parcel No. 12306405), and an alleyway that extends
southwest from 120 E. Kingston Avenue to East Boulevard. The buildings at the
Brownfields Property have been demolished and the property is currently under
development. At the time that the NC Brownfields Program Application was submitted,
the property was developed with a pharmacy/convenience store and three vacant
commercial buildings.
A Brownfields Property Application Amendment was submitted on January 18, 2022, for
the purpose of reducing the size of the property to the current parcel.
Redevelopment Plans:
Planned redevelopment of the Brownfields Property includes demolition of the existing
buildings and construction of a high-density residential building.
Site History:
The Brownfields Property was developed with at least two single-family residences and
auxiliary structures around the early 1900s. A gas station, convenience store, and tire
shop operated in the eastern and central portions of the property. The tire shop and gas
station were razed in the early 1960s and another gas station and convenience store were
developed in the eastern portion of the property (Mini-General Store/ Dilworth Auto
Service). That gas station ceased operations in the late 2000s and the buildings were
demolished in 2018.
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Around 1953, an upholstery and shipping warehouse was located in the southern portion
of the Brownfields Property, one of the former residences located in northern portion of
the property was utilized for retail purposes, and another building was occupied by a
prosthetics company. The southern property building was occupied by health clubs and
film companies from the 1970s until recently. Soil and groundwater impacts were
identified in connection with the November 2008 removal of two gasoline underground
storage tanks, associated product lines and dispensers (Mini-General Store / Dilworth
Auto Service 1700 South Boulevard; UST Incident# 36614). The DEQ issued a Notice of
No Further Action for Incident #36614 and a Notice of Residual Petroleum on January
22, 2009. Additional environmental remediation and assessment activities were
conducted at 1700 South Blvd. (Incident #36614) in January and February 2008.
Remediation activities included the excavation and off-site disposal of 490 tons of soil
from the former product dispenser island area. Based on the soil confirmatory sampling
and groundwater sampling results, the DEQ issued a NFA on April 6, 2018, and a
Cancellation of Notice of Residual Petroleum on June 21, 2018.
The Okey Hosiery (BF#22069-18-060) Brownfields Property is located adjacent to the
northwestern property boundary. No significant groundwater contaminants were
identified at the property. In addition, Dilworth Auto II (26004-22-060) Brownfields
Property is located adjacent to the south.
Brownfields Environmental Assessment Activities
In November 2020, H&H performed soil, groundwater, exterior soil gas sampling and
methane screening activities at the Brownfields Property to evaluate potential areas of
environmental concern associated with historical on-site operations. Laboratory
analytical results indicated the presence of several volatile organic compounds (VOCs) in
soil that exceeded DEQ Residential Preliminary Soil Remediation Goals (PSRGs) in the
vicinity of the former gas station in the northeastern portion of the Brownfields Property.
Results of methane gas screening activities conducted indicated that methane is not
present above the NC Brownfields residential threshold. There were no indications that
methane would be an issue and the assessment was conducted for due diligence screening
purposes. The groundwater flow direction is estimated to be towards the northwest.
During the 2020 assessment, ground penetrating radar (GPR) was used to survey areas of
known or suspected current/former USTs at the Brownfields Property. The results of the
GPR survey indicated the presence of at least one heating oil UST adjacent to the
northwest side of the building along E. Kingston Avenue. GPR activities also indicated
anomalous data in the vicinity of a former gas station located in the northeastern portion
of the Brownfields Property where three USTs are shown on Sanborn maps. The presence
of USTs was not confirmed in this area using GPR or a probe rod.
Environmental assessment activities were conducted in August 2021 in accordance with a
DEQ-approved work plan. Environmental media sampled included soil and exterior soil
gas. Laboratory analytical results indicated that VOCs and semi-volatile organic
compounds (SVOCs) exceeded Residential PSRGs in one soil sample. Three exterior soil
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gas samples were collected near the location of the former gasoline station in August
2021 and analyzed for VOCs.
Potential Receptors:
Potential receptors are: construction workers, on-site workers, and future residents.
A Brownfields Receptor Survey was completed on August 2, 2021. No water supply
wells were identified within 1,500 feet of the Brownfields Property. Surrounding
properties are served by municipal water.
Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property: soil,
soil gas and groundwater. DEQ relies on the following data to base its conclusions
regarding the subject property and its suitability for its intended reuse. A summary of
data exceeding screening levels is found in Exhibit 2 of the Notice of Brownfields
Property.
Soil
The following compounds were detected in soil above NC Residential Preliminary Soil
Remediation Goals. The highest concentration detected for each constituent is listed
below.
Arsenic was detected in several soil samples up to 5.9 mg/kg. The arsenic
concentrations were comparable to regional background arsenic concentrations.
Ethylbenzene - 52 mg/kg
Hexavalent - 2.2 mg/kg
Lead - 630 mg/kg
Naphthalene - 15 mg/kg
1,2,4-Trimethylbenzene - 63 mg/kg
Groundwater
The following compounds were detected in groundwater above NC 2L Groundwater
Quality Standards. The highest detected concentration for each compound is listed below.
Benzene - 30,000 µg/l
1,2-Dichloroethane - 89 µg/l
Ethylbenzene - 3,000 µg/l
Isopropylbenzene -110 µg/l
Methyl Butyl Ketone - 40 µg/l
Methyl-tert-Butyl Ether - 1,400 µg/l
2-Methylnaphthalene – 74 µg/l
Naphthalene – 450 µg/l
Tetrachloroethylene – 0.74 µg/l
Toluene – 34,000 µg/l
Total Xylenes – 14,000 µg/l
Compounds detected in groundwater with no established screening levels
included cyclohexane, methocyclohexane, methyl acetate, and 3/4-methylphenol.
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Surface Water
No surface water is present at the property.
Exterior Soil Gas
The following compounds were detected in exterior soil gas samples at concentrations
above NC DEQ Residential VISLs. The highest detection for each compound detected is
listed below.
Benzene – 2,200 g/m3
Chloroform – 44 J g/m3
1,2-Dichloroethane – 95 g/m3
Ethylbenzene – 44,000 g/m3
Heptane – 28,000 g/m3
Hexane – 29,000 g/m3
Naphthalene – 2,700 g/m3
1,2,4-Trimethylbenzene – 34,000 g/m3
1,3,5-Trimethylbenzene – 9,200 g/m3
m&p-Xylenes – 48,000 g/m3
o-Xylene – 16,000 g/m3
Sub-Slab Vapor
No sub-slab samples were collected. Existing buildings have been demolished.
Indoor Air
No indoor air samples were collected. Existing buildings have been demolished.
Risk Calculations
Risk calculations were performed using the January 2022 DEQ Risk Calculator.
The sampling locations exhibiting the highest site wide concentrations for exterior soil
gas, soil, and groundwater were used for calculating risk for the respective media. Results
of the risk evaluation are presented in the following table.
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Risk for Individual Pathways Output Form 1A
Version Date: January 2022
Basis: November 2021 EPA RSL Table
Site ID: 24051-20-060
Exposure Unit ID: GW, Soil and SG Worst Case
Receptor Pathway
Carcinogenic
Risk Hazard Index Risk exceeded?
Soil 2.2E-05 4.5E-01 NO
Groundwater Use* 7.2E-02 1.1E+03 YES
Soil 3.8E-06 5.5E-02 NO
Groundwater Use* 1.7E-02 2.4E+02 YES
Construction Worker Soil 1.2E-06 2.7E-01 NO
Soil 1.0E-05 1.8E-01 NO
Surface Water* NC NC NC
Receptor Pathway
Carcinogenic
Risk Hazard Index Risk exceeded?
Groundwater to Indoor Air 2.0E-02 2.6E+02 YES
Soil Gas to Indoor Air 2.6E-03 3.4E+02 YES
Indoor Air NC NC NC
Groundwater to Indoor Air 4.6E-03 6.2E+01 YES
Soil Gas to Indoor Air 1.9E-04 2.7E+01 YES
Indoor Air NC NC NC
VAPOR INTRUSION CALCULATORS
Resident
Non-Residential Worker
DIRECT CONTACT SOIL AND WATER CALCULATORS
Resident
Non-Residential Worker
Recreator/Trespasser
Based on the results of the risk evaluation, the Residential Hazard Index risk threshold
was exceeded for groundwater use, groundwater to indoor air, and exterior soil gas.
Elevated concentrations of petroleum-related compounds detected in groundwater will
require a land use restriction prohibiting the use of groundwater; however, municipal
water is available at the Brownfields Property, further minimizing the potential risks. An
Environmental Management Plan (EMP), approved by DEQ, will be required before the
start of soil grading or excavation activities to prevent exposure to site workers and future
residents from unacceptable levels of contaminants, and to manage the safe handling and
disposal of potentially contaminated materials during construction. In addition, final
grade soil sampling will be required prior to occupying the Brownfields Property. A
vapor intrusion mitigation system is required.
Required Land Use Restrictions:
The standard land use restrictions including land use, Environmental Management Plan
and reporting requirements, prohibition on groundwater use, soil restrictions, final grade
sampling, the need for vapor intrusion mitigation, access, notification, and prohibition on
the use of known contaminants, and the annual land use update obligation are required
for this Brownfields Agreement.
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.
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Property Management:
Environmental Management Plan
A vapor intrusion mitigation system is required and is being installed. Petroleum-
related compounds are the primary constituents of concern.
Pre-occupancy and semi-annual post-occupancy sub-slab soil gas sampling
Final grade soil sampling required
Trichloroethylene not detected in soil gas or groundwater