22009 CNAD Decision Memorandum_20180809

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DECISION MEMORANDUM
DATE: 8/9/2018 FROM: Bill Schmithorst TO: BF Assessment File
RE: Charlotte Naval Ammo Depot 3100 Nevada Boulevard BF # 22009-18-060
Based on the following information, it has been determined that the above referenced site, whose intended use is for no uses other than light industrial, warehousing, office, and parking, can be made suitable for such uses. Introduction:
The Brownfields Property (Parcel # 20310103) is 17.082 acres of vacant and wooded land with the exception of an abandoned railroad spur. The Brownfields Property is bordered by property used for warehousing and light industrial purposes. Redevelopment Plans:
The Prospective Developer intends to build a large warehouse on the Brownfields Property for potential light industrial and warehousing uses. This proposed use is compatible with the surrounding area. Site History:
The Brownfields Property is currently owned by Arrowood Land Investors, LLC and was purchased from Arrowood Southern Company, LLC on May 11, 2017. The property was previously developed starting in 1942 as part of the Charlotte Naval Ammunition Depot (CNAD) and used for munition disarmament and manufacturing. Several structures
associated with these activities were present on the Brownfields Property until their
demolishment in the 1980s. Recent owners of the Brownfields Property have included the U.S. Department of Defense. The Brownfields Property (formerly part of CNAD Area 1) is currently identified as an
active site under the NC Federal Remediation Branch (Site ID NC9799F4900) and
formerly contained a building used as part of the Charlotte Naval Ammunition Depot munitions manufacturing operations. Environmental contamination was discovered in the 1980s and resulted from a degreasing operation located at former Area 2 Building 2-30 on the adjoining property. The United States Army Corps of Engineers (USACE) is
leading the environmental remediation efforts on behalf of the U.S. Department of
Defense. A groundwater plume containing volatile organic compounds (VOCs), including trichloroethylene(TCE), has migrated onto the Brownfields Property from the adjoining property. A series of environmental assessments and remedial investigations were conducted by USACE on the Brownfields Property and surrounding properties from
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the 1980s until the early 2000s. In 2013, the USACE awarded a contract for remediation of groundwater contamination at the Brownfields Property and adjoining property to
address groundwater impacts in the transition and bedrock zones. The remediation technologies selected included injection of molasses to enhance bioremediation of chlorinated VOCs in groundwater and monitored natural attenuation. According to the March 2017 Remedial Action and Performance Monitoring Report, 14 injection wells have been installed at the Brownfields Property and the last documented injection event
was performed in July 2016. Groundwater monitoring results indicate a reduction in trichloroethylene after two years along with an increase in cis-1,2-Dichloroethene and vinyl chloride, associated breakdown or daughter products of TCE. Ongoing groundwater monitoring activities are being managed by USACE. Subsequent assessment activities conducted by Hart & Hickman on behalf of the Prospective Developer did not detect
contaminants in soil above Non-Residential screening levels. Potential Receptors: Potential receptors are: construction workers, on-site workers, visitors, and trespassers. A receptor survey identified no water supply wells within 1,500 feet of the site. An
unnamed surface water tributary was sampled onsite and no VOCs, SVOCs, or metals were detected above screening levels. Contaminated Media: DEQ has evaluated data collected from the following media at the subject property:
groundwater, soil, sediment and surface water. DEQ relies on the following data to base its conclusions regarding the subject property and its suitability for its intended reuse. Soil A soil assessment was conducted on May 1, 2018 around the former location of building
1-81. Five subsurface soil samples and two background soil samples were collected. The soil samples collected around the location of the former building were submitted to a NC certified laboratory for the analysis of VOCs, semi-volatile compounds (SVOCs), RCRA Metals, and polychlorinated biphenyl (PCB) congeners. No analytes were detected above
site screening levels. Details regarding the soil investigation can be found in Brownfields
Assessment Report, Charlotte Naval Ammo Depot, Hart & Hickman, June 2018. Groundwater Three existing shallow groundwater monitoring wells located on the Brownfields
Property were sampled by USACE for VOCs in March 2018. Data indicated that
concentrations of trichloroethylene exceeded NC 2L Groundwater Standards in all three wells. In addition, cis-1,2-Dichloroethene and vinyl chloride exceeded NC 2L Groundwater Standards in one well (NADMW-58). North Carolina Groundwater Non-Residential Vapor Intrusion Screening Levels were exceeded for trichloroethylene and
vinyl chloride.

Surface Water and Sediment One co-located surface water and sediment sample was collected on the Brownfields Property on May 1, 2018 from an unnamed tributary of Steel Creek and submitted to a
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laboratory for the analysis of VOCs, SVOCs, RCRA Metals and PCBs. The sample was located downgradient from the former onsite building. Laboratory results indicated no
exceedances of screening levels.
Soil gas: The depth to groundwater on the Brownfields Property is extremely shallow and does not allow for the collection of soil gas, or sub-slab samples. There are also no slabs currently
on the property.

Risk Calculations Risk Calculations were performed using Excel worksheets provided by Sandy Mort, NCDEQ Brownfields Toxicologist using data from the groundwater monitoring well with
the highest reported VOC concentrations (NADMW-58). The risk calculations indicated the following based on available data, including the following media: groundwater and indoor air: Table 1
Summary of Risk Assessment Output
Receptor Pathway LICR Hazard Index Risk exceeded?
Non-Residential Worker Groundwater Combined
Pathways* 3.4E-04 3.9E+01 YES
Non-Residential Worker Groundwater to Indoor Air 8.5E-05 1.6E+01 YES
Red shading LICR> 1E-04 or HI> 1. LICR = Lifetime Incremental Cancer Risk HI = Hazard Index
Due to elevated concentrations of VOCs in groundwater, a vapor mitigation system will be required for buildings constructed on the Brownfields Property. 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 warehousing, light industrial, office and Parking.
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. 5. Soil Import/Export. 6. No new buildings without DEQ approved vapor mitigation measures.
8. EMP 9. Access to Brownfields Property for environmental assessment. 10. NBP reference in deed.
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11. No contaminants on property except for de minimis amounts, fluid in vehicles, fuels for generators/equipment.
12. LURU submission January 1st
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