22076 West Boulevard Decision Memorandum_20191021

1
DECISION MEMORANDUM
DATE: October 1, 2019 FROM: Bill Schmithorst TO: Project Files
RE: West Boulevard 200, 204, 208, 212, 216 and 224 West Boulevard; 1721 and 1725 South Tryon Street
Charlotte, Mecklenburg County BF # 22076-18-060 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, retail, office,
restaurant, parking, open space and, with DEQ’s prior written approval, other commercial uses, can be made suitable for such uses. Introduction: The Brownfields Property (Tax PINs 12306219, 12306207, 12306206, 12306205,
12306204, 12306201, 12306217 and 12306218) is approximately 1.8 acres and is currently developed along West Boulevard with three former residences used for commercial purposes including a salon, a clothing store, and a law office. The western portion of the Brownfields Property at the West Boulevard and S. Tyron Street intersection is developed with a restaurant building and the northwestern portion of the
Brownfields Property along S. Tryon Street is developed with a vacant residence. Remaining portions of the Brownfields Property include vacant undeveloped parcels. Redevelopment Plans:
The Prospective Developer intends to develop multi-story high density residential, retail,
restaurant, office, parking and commercial business space. Currently, it is not anticipated that fill will be imported to or exported from the site. Site History:
The Brownfields Property along West Boulevard is developed with three former
residences that have most recently been used for commercial purposes including a salon, a clothing store, and a law office. The western portion of the Brownfields Property at the West Boulevard and S. Tyron Street intersection is developed with a restaurant building and the northwestern portion of the Brownfields Property along S. Tryon Street is
developed with a residence that is currently vacant. Remaining portions of the
Brownfields Property include undeveloped parcels. The southern portion of the Brownfields Property along West Boulevard and the western portion of the Brownfields Property was historically developed with residences as early
2
as the 1920s. The residential structures were removed from the Brownfields Property over time or were converted for use as commercial tenant spaces, with the exception of
the residence located at 1725 S. Tryon that is currently unoccupied. The western corner of the Brownfields Property at the West Boulevard and S. Tryon Street intersection (224 West Boulevard) was undeveloped land as early as the 1920s until the late 1940s to early 1950s when it was developed with a gasoline filling station facility. Operations on the western corner parcel included a filling station until the 1960s, an auto repair and
detailing business from the 1970s until the 1980s, and a restaurant from the 1980s until the early to mid-2000s. The western Brownfields Property building remained vacant from the mid-2000s until the current restaurant (Sauceman’s) opened in approximately 2010. The northwestern corner of the Brownfields Property is part of the adjacent Wilmore Centennial Park at Southend.
Based on historical groundwater sampling results, it is suspected that VOCs are migrating in groundwater to the Brownfields Property from offsite sources. The Centro Brownfields Property (BF# 16048-12-060) is located to the east of the Brownfields Property.
Environmental Site Assessments In March 2009, Coastal Environmental Consulting, Inc (CEC) completed Phase I & Limited Phase II Environmental Site Assessment activities in connection with the 224 West Boulevard parcel (western corner parcel). There are no records indicating that the underground storage tanks were removed or abandoned, therefore, assessment activities
included a ground penetrating radar (GPR) survey to identify any remaining USTs associated with the former use as a filling station. The GPR survey did not find indication of subsurface USTs. Three soil samples were collected from the former UST basin and former dispenser island areas for the analysis of total petroleum hydrocarbons as gasoline range organics and diesel range organics (TPH-GRO and TPH-DRO).
Laboratory analytical results indicated that no compounds were detected in the soil samples at concentrations above the laboratory reporting limits. One temporary groundwater monitoring well was installed at the former UST basin and sampled for VOCs, semi-volatile organic compounds (SVOCs) and TPH. Laboratory results indicated
that tetrachloroethylene was detected at a concentration above NC 2L Groundwater
Standards. In January 2010, CEC completed additional soil and groundwater assessment activities in the western portion of the Brownfields Property to further evaluate the source of
tetrachloroethyleneimpacts identified in the March 2009 groundwater sample. Four
temporary groundwater monitoring wells were installed along the southern Brownfields Property boundary near West Boulevard to evaluate the potential for impacts from nearby off-site sources. CEC also collected two additional soil samples (shallow and deeper soil samples) from each temporary monitoring well boring, and two additional soil samples
were collected from a boring advanced in the area of the former UST basin. Soil samples
and groundwater samples were submitted to a laboratory for the analysis of VOCs. Soil sample analytical results indicated that no VOCs were detected at concentrations above the laboratory reporting limits. Groundwater assessment results indicated that low levels
3
of TCE were detected in samples collected from the four upgradient temporary monitoring wells at concentrations exceeding the NC 2L Groundwater Standards.
In August 2015, CEC conducted additional soil and groundwater sampling along the southern Brownfields Property boundary. Soil and groundwater assessment activities included advancing four soil borings for collection of additional shallow and deeper soil samples. Three of the soil borings were converted to temporary monitoring wells for
collection of groundwater samples to further evaluate the source of VOCs in groundwater. Soil sample analytical results indicated that no compounds were detected at concentrations exceeding the PSRGs. Low levels of tetrachloroethylene (or PCE) and TCE were detected in each groundwater sample at concentrations exceeding the NC 2L Groundwater Standards.
In April 2019, in accordance with a DEQ-approved Brownfields Assessment Work Plan dated March 14, 2019, Hart & Hickman, PC completed additional groundwater, soil and soil gas assessment activities at the Brownfields Property. Four temporary groundwater monitoring wells were installed and groundwater samples were collected from each
monitoring wells for the analysis of VOCs, SVOCs and RCRA metals. Groundwater sample analytical results confirmed the presence of low level chlorinated solvent impacts near the southern Brownfields Property boundary. Exterior soil gas assessment activities completed in April 2019 included the installation
and sampling of eight soil gas sampling points to evaluate the potential for impacts to on-site soil gas from historical activities and from offsite properties in the vicinity of the Brownfields Property. Soil gas samples were submitted to a laboratory for the analysis of VOCs by EPA Method TO-15. Soil gas assessment results in the western portion of the Brownfields Property indicated that several VOCs including benzene, 1,2-dichloroethane,
ethylbenzene, hexane, naphthalene, PCE, 1,2,4-trimethylbenzene, and 1,3,5-trimethylbenzene were detected at concentrations above the Residential Soil Gas Screening Levels (SGSLs). Soil gas assessment results in the eastern portion of the Site indicate that PCE was detected at a concentration above the Residential and Non-
Residential SGSLs.
Soil assessment activities completed in April 2019 were conducted at the Brownfields Property as part of the April 2019 Brownfields Assessment. Soil samples were submitted to a laboratory for the analysis of semi-volatile organic compounds (VOCs), SVOCs, and
Resource Conservation and Recovery Act (RCRA) metals. Laboratory analytical results
indicated that no VOCs or SVOCs were detected at concentrations above the IHSB Residential PSRGs. In addition, metal detections were consistent with site-specific background metal concentrations, with the exception of lead concentrations detected in soil samples collected within the roof drip lines of the 1725 S. Tryon Street structure and
former 216 West Boulevard structure. Results of shallow soil samples collected in these
locations on the Brownfields Property indicate that lead was detected at concentrations exceeding the IHSB Residential PSRG and the site-specific background concentrations.
4
Potential Receptors: Potential receptors are: construction workers, on-site workers, residents, visitors, and
trespassers. A receptor survey was conducted in the area surrounding the Brownfields Property. The area is urban and is served by municipal water and no water supply wells were identified within 1,500 feet of the property. Contaminated Media:
DEQ has evaluated data collected from the following media at the subject property: soil, groundwater, and soil gas. DEQ relies on the following data to base its conclusions regarding the subject property and its suitability for its intended reuse. A summary of contaminated media above screening standards is presented in Exhibit 2 of the Brownfields Agreement. In addition, a comprehensive summary of site environmental
assessment data can be found in Brownfields Assessment Report, West Boulevard, Hart & Hickman, May 21, 2019. Soil Soil samples collected in April 2019 exhibited exceedances of Residential PSRGs for
metals. Laboratory results indicated an exceedance of the Residential PSRG for lead in surface soil samples COMP-2 (607 mg/kg) and COMP-6 (689 mg/kg). The two composite soil samples were collected within the roof drip lines of a former and existing structure. Laboratory results also indicated that arsenic and hexavalent chromium exceeded Residential PSRGs in several samples. Both arsenic and hexavalent chromium
were detected at low concentrations consistent with sampling results from other brownfields properties in the Charlotte area. There are no records of a release of either arsenic or hexavalent chromium at the Brownfields Property. Groundwater
One groundwater monitoring well (GW-1) was installed in the former UST basin in March 2009 and sampled for the analysis of VOCs. Trichloroethene exceeded NCAC 2L Groundwater Standards at a concentration of 5.42 µg/L.
Three temporary groundwater monitoring wells (B-7, B-8, and B-9) were installed at the
Brownfields Property in June 2015 and sampled for VOCs. Laboratory results indicated that tetrachloroethylene exceeded NCAC 2L Groundwater Standards at each well at concentrations up to 3.8 µg/L (B-7). Trichloroethylene was also detected in each monitoring well up to a concentration of 49 µg/L (B-7), exceeding NCAC 2L
Groundwater Standards.
Additional assessment activities in April 2019 included the installation of four temporary groundwater monitoring wells. Each well was sampled for VOCs, SVOCs, and RCRA metals. Laboratory results indicated that tetrachloroethylene exceeded NCAC 2L
Groundwater Standards in temporary groundwater monitoring well TMW-3 at a
concentration of 1.6 µg/L. Trichloroethylene exceeded NCAC 2L Groundwater Standards at monitoring well TMW-3 at a concentration of 19.9 µg/L. Chromium exceeded NCAC 2L at monitoring wells TMW-1, TMW-3, and TWM-4 at concentrations up to 35 µg/L.
5
In addition, lead exceeded NCAC 2L at monitoring well TMW-4 at a concentration of 26.1 µg/L.
Residential groundwater to indoor air SGSLs were also exceeded. Laboratory results indicate groundwater vapor intrusion risks for trichloroethylene in groundwater (GW-1, TW-2, TW-3, TW-4, TW-5, B-7, B-8, B-9, and TMW-3).
Soil Vapor In April 2019, eight exterior soil gas sampling points were installed and sampled at the Brownfields Property for VOC analysis. PCE was detected in soil gas samples SG-3, SG-5, SG-6, and SG-7 (ranging from 715 μg/m3 to 1,660 μg/m3) at concentrations above the Residential SGSL of 280 μg/m3. Concentrations of PCE were also detected in soil
gas samples SG-2 (8,370 μg/m3) and the SG-4 (4,870 μg/m3) soil gas sample and its duplicate soil gas sample DUP-SG (4,530 μg/m3) at levels above Residential SGSLs. Concentrations of benzene (4,840 μg/m3), 1,2-dichloroethane (3,430 μg/m3), ethylbenzene (2,170 μg/m3), 1,2,4-trimethylbenzene (1,480 μg/m3) hexane (98,700 μg/m3), naphthalene (2,370 J μg/m3), and 1,3,5-trimethylbenzene (22,400 μg/m3) were
detected in soil gas sample SG-3 at levels above their respective Residential SGSLs.

Risk Calculations Risk Calculations were performed using Excel worksheets provided by Sandy Mort, NCDEQ Brownfields Toxicologist. For the purposes of providing a conservative estimate
of risk, data from the samples with the highest concentrations were used in the risk model. This included SG-3 and SG-4 combined concentrations for soil gas, COMP-6 for soil, TMW-3 for groundwater. The risk calculations indicated the following based on available data, including the following media: groundwater, shallow soil, and soil gas:

DIRECT CONTACT SOIL AND WATER CALCULATORS
Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded?
Resident Soil 6.9E-06 1.7E-01 NO
Groundwater Use 1.0E-04 7.8E+00 YES
Non-Residential
Worker
Soil 1.6E-06 1.2E-02 NO
Groundwater Use 1.9E-05 1.7E+00 YES
Construction Worker Soil 2.6E-07 1.4E-01 NO
Recreator/Trespasser Soil 3.8E-06 9.4E-02 NO
VAPOR INTRUSION CALCULATORS
Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded?
Resident
Groundwater to Indoor Air 1.7E-05 3.9E+00 YES
Soil Gas to Indoor Air 2.3E-03 6.1E+01 YES
6
Non-Residential Worker
Groundwater to Indoor Air 2.7E-06 9.3E-01 NO
Soil Gas to Indoor Air 1.7E-04 4.8E+00 YES
Red shading LICR> 1E-04 or HI> 1. LICR = Lifetime Incremental Cancer Risk
HI = Hazard Index Results from the risk analysis indicate that groundwater and soil gas exceed an acceptable risk requiring vapor mitigation measures for residential and non-residential use. The PD will submit a Vapor Intrusion Mitigation System Plan to the DEQ for approval and install
the system according to the VIMS Plan before any new buildings are occupied. Construction work conducted at the Brownfields Property will be completed under a DEQ-approved Environmental Management Plan to control potential risks from environmental contamination. In addition, final grade soil sampling will be conducted before the Brownfields Property can be occupied for its proposed use.
Required Land Use Restrictions: 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.
1. No use other than for high density residential, retail, office, open space, parking, restaurant, and, subject to DEQ’s prior written approval, other commercial uses. 2. No groundwater use 3. No disturbing soil without DEQ approval or for landscape/mowing/pruning/repair of
underground infrastructure (written notice to DEQ)/work for EMP. 4. Soil Import/Export protocol is followed. 5. Standard VI LUR; a VIMS will be required. 6. EMP 7. Access to Brownfields Property for environmental assessment.
8. NBP reference in deed. 9. No contaminants on property except for de minimis amounts, fluid in vehicles, fuels for generators/equipment. 10. Ongoing maintenance of vapor mitigation systems. 11. Final grade soil sampling for RCRA metals, SVOCs, and VOCs will be conducted in
exposed areas. 12. LURU submission January 1st