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Home My WebLink About20022_Mount Hope II _DM_20170707DECISION MEMORANDUM DATE: July 7, 2017 FROM: Jordan Thompson TO: BF Assessment File RE: Mount Hope II 2000 Donald Ross Road Charlotte, Mecklenburg County BF # 20022-16-060 Based on the following information, it has been determined that the above referenced site, whose intended use is for retail, warehousing, office, light industrial, 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 one parcel totaling 2.95 acres located east of Donald Ross Road in Charlotte, Mecklenburg County. The Brownfields Property is developed with one building and associated parking lots and is currently unoccupied. Groundwater and soil are contaminated at the subject property due to historical operations by Mount Hope Machinery and/or migration from off-site sources. The surrounding area is commercial, retail, industrial, and residential. Mount Hope Machinery is listed in the Inactive Hazardous Site Branch (IHSB) Inventory Site Number NONCD0002101. The Responsible Party (RP), Xerium Technologies, Inc., is currently working with the IHSB Voluntary Registered Environmental Consultant (REC) Program and has an approved Remedial Action Plan. They are now conducting annual groundwater sampling for a monitored natural attention remedy. The most recent sampling event was completed in May 2017. Redevelopment Plans: The Brownfields Property is proposed to be redeveloped with office, warehousing, and distribution tenants within the existing building. Additional tenants will be sought by the Prospective Developer following completion of the Brownfields Agreement. Site History: The Brownfields Property totals 2.956 acres and is developed with a building that totals 27,785 square ft and was constructed in 1961. The property was vacant land with a roadway in the northwest portion prior to 1938 until the early 1960s. The property was occupied by various machine shops until 2013 and previously operated under a Resource Conservation and Recovery Act (RCRA) Small Quantity Generator (SQG) permit. The building has most recently been leased to the PD for warehousing operations and the PD will purchase the property immediately preceding recordation of the Brownfields Agreement. Potential Receptors: Potential receptors are: construction workers, on-site workers, visitors, and trespassers. A well receptor survey was completed in March 1994 and identified two water supply wells on the north adjacent Southern Metals property and three irrigation wells on the golf course to the west. An updated receptor survey completed in January 2010 identified six commercial wells in the vicinity: two wells are located upgradient to the north on the Southern Metals Company property and four wells are located to the west on the Carolina Golf Club property. All the wells are utilized for non-contact uses. Four residential water supply wells were identified and determined to be out of use or removed. In March 2017, the receptor survey was updated by Mid-Atlantic and the six previously identified commercial water wells were confirmed to be present. Mid-Atlantic did not identify residential water supply wells near the Brownfields Property. Contaminated Media: DEQ has evaluated data collected from the following media at the subject property: soil, groundwater, and indoor air. DEQ relies on the following data to base its conclusions regarding the subject property and its suitability for its intended reuse. A subgrade, concrete block OWS was installed in 1973 to collect discharge from floor drains within the building. The OWS was taken out of service by 1984 and removed in 1992. Environmental assessment activities initiated in 1989 identified soil and groundwater impacts in the vicinity of the OWS system and impacted soils were excavated in 1992 and 2010. Remediation activities at the Brownfields Property have included soil excavation, soil vapor extraction, and groundwater air sparging. Soil The most recent soil assessment was conducted in November 2010 in accordance with the NCDEQ REC Program and detailed in a Soil Remediation Completion Report. Soil was excavated from the vicinity of the former OWS system in the northern portion of the Brownfields Property and confirmation soil samples indicated that soils impacted above DEQ Industrial Screening Levels were removed from the Brownfields Property. Synthetic Precipitation Leaching Procedure (SPLP) results from the remaining soils did not identify the potential for the remaining impacts to leach into groundwater. Surface discharges of varsol and mineral spirits also reportedly occurred on the Brownfields Property between 1960 and 1973. Soil sampling in the vicinity of the reported discharge identified impacts of VOCs above Protection of Groundwater screening levels but below DEQ Industrial Screening Levels. The contaminants of concern identified in the soil from the surface discharge area were not detected in a downgradient monitoring well. Additionally, a SPLP was completed and the potential for impacts to leach to groundwater was considered low. Based on the SPLP results and the lack of soil impacts above DEQ Industrial Screening Levels and proposed future use of the Brownfields Property, soil excavation was not completed in the vicinity of the surface discharge area. The table below demonstrates the hazard quotient of soils remaining on-site based on the highest concentrations identified in soils that were not excavated. The non-residential hazard quotient is 0.00498 for soils remaining on the property. Refer to the attached Soil Remediation Completion Report dated November 2010 and Exhibit 2. Groundwater Groundwater monitoring wells have been sampled on the property since the early 1990s as discussed above. Seven monitoring wells within the network were sampled in July 2016 per REC program requirements. Groundwater impacts of VOCs above 2L Standards were identified within the sampled monitoring wells during the most recent assessment. Refer to attached Exhibit 2 for detected concentrations of VOCs. The highest concentrations detected during the most recent sampling event were below the VISL Calculator Hazard Index of 1. See table below and attached Remedial Action Progress Report dated July 25, 2016. Surface Water Surface water is not located on the property. The nearest water body is a tributary of Irwin Creek approximately 60 ft east of the property. Soil Vapor No soil vapor testing was completed. Sub-Slab Vapor No sub-slab testing was completed. Indoor Air Four indoor air quality samples were collected in March 2016. Trichloroethylene was detected in one sample within the office space above DEQ Indoor Air Screening Criteria (1.8 ppm versus standard of 1.75 µg/m³. This concentration was below the VISL Calculator Hazard Index of 1. See table below and attached Indoor Air Quality Summary dated August 26, 2016 Risk Calculations Risk Calculations were performed using Excel worksheets provided by Sandy Mort, NCDEQ Brownfields Toxicologist. The Brownfields Property was evaluated as a whole, based on the acceptance into the REC Program and small number of monitoring wells sampled during the 2016 monitoring event. The risk calculations indicated the following based on available data, including the following media: groundwater, residual soil (based on confirmatory soil data), and indoor air: Medium Site Area Non-Residential LICR HI Groundwater 2016 Sample of Active Wells 1.4 x 10-6 0.165 Indoor Air Site Building 6.1 x 10-7 0.24 Residual Soil Max Remaining Soils 1.69 x 10-7 0.00498 Red shading LICR> 1E-04 or HI> 1. LICR = Lifetime Incremental Cancer Risk HI = Hazard Index Based on the proposed non-residential use of the Brownfields Property, groundwater, soil, and indoor air hazard quotients are acceptable. Final grade sampling will be required during any soil disturbance as part of an EMP to ensure lack of potential exposure. 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: - No child/adult care or schools - No groundwater use - No surface water use other than stormwater under appropriate permit - No soil disturbance - No soil brought onto or removed from property without DEQ approval - No enclosed building constructed without DEQ approval of vapor intrusion assessment - EMP required for redevelopment - DEQ shall not be denied access - Deed conveyance of BFA - Known contaminants present on the property may not be kept or stored on-site - MWs to be abandoned, except those associated with REC monitoring - MW replacement if damaged/destroyed - LURU submittal Also, an additional round of indoor air sampling and/or indoor/outdoor radon testing may be proposed to address variability in indoor air results. This will need no additional language and would be a technical condition we would impose under the DEQ Approval of VI assessment under the proposed LURs above