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HomeMy WebLinkAbout22037_Clayton Spinning Mill_Decision Memo_2019-04-02DECISION MEMORANDUM DATE: April 3, 2019 FROM: Brad Atkinson TO: BF Assessment File RE: Clayton Spinning Mill 300 Mill Street Clayton, Johnston County BF # 22037-18-051 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, office, restaurant, open space, recreation, parking, and subject to DEQ’s prior written approval, other commercial uses, can be made suitable for such uses. Introduction: This Agreement concerns 31.5977 acres located at 300 Mill Street in Clayton, NC. The property is made up of six parcels with North Carolina Parcel Identification Numbers 06918-40-2748, 6918-30-8385, 6918-30-2104, 6918-30-4740, 6918-30-5328, and 6806- 39-4886. All six parcels were recombined on March 23, 2019 into three new parcels with parcel identification numbers 166918-30-7238, 166918-40-3804, and 166918-30-4740. The Brownfields Property is bordered to the north by Central Street, Creekside Drive, single-family residences, wooded land, and a United States Post Office facility; to the east by single-family residences, and wooded land; to the southeast and south by The Arbors apartment complex; to the west by Creekside Drive, a United States Post Office facility, East Front Street and wooded land; and to the south by East Front Street and wooded land. The former cotton mill and associated small office building on the Brownfields Property closed in 1976 and are currently vacant. A cell tower is the only productive use of any part of the site at present. A stream flows through the property to the southeast of the spinning mill parcel. Redevelopment Plans: The Prospective Developer (PD) is Clayton Spinning Mill Investments, LLC of Greenville, North Carolina. Members of the company have extensive experience developing high-density multi-family, office, retail, and commercial properties in North Carolina. The existing mill building will be renovated with condominiums, and six or seven new apartment buildings will be constructed on the Brownfields Property. Site History: The Brownfield Property was developed as a cotton spinning mill in 1900. The business was in operation under different names until 1976 when the business ceased operations. The names of the various operators are included in the BFA. The mill was only used for spinning operations and not for dyeing operations. An associated small office building, multiple out-buildings and several single family residences were located on the Brownfield Property. Only the mill building and the office remain. One 5,000-gallon and one 1,000-gallon fuel oil tank at the southern corner of the cotton mill were identified on Sanborn maps. The tanks are not present above ground and tank basins could not be located using ground penetration radar. The tanks are believed to have been removed at an unknown previous date. DEQ does not list the site in the registered underground storage tanks database. A lumber planing mill and associated buildings were present on a portion of the Brownfields Property no later than 1909. The date the planing mill ceased operations is not known, but, as evidenced by aerial photos, the majority of the planing mill buildings had been removed from the site by 1961. None remain today. A fuel storage tank associated with the planing mill facility was identified on Sanborn maps. No fuel tank is currently present above ground and no tank basin could be located using ground penetration radar. The tank is believed to have been removed at an unknown previous date. DEQ does not list the site in the registered underground storage tanks database. A cell tower has been present on site since approximately 2006. The PD purchased a portion of the Brownfields Property on June 6, 2018 and the remaining portions on September 7, 2018. Potential Receptors: Potential receptors are: construction workers, on-site workers, future residents, visitors, and trespassers. Contaminated Media: DEQ has evaluated data collected from the following media at the subject property: groundwater, soil, soil-vapor, sub-slab soil-vapor, indoor air (crawl space air), and surface water and stream sediment. DEQ relies on the following data to base its conclusions regarding the subject property and its suitability for its intended reuse. Soil Soil at the Brownfields Property was screened with a PID capable of detecting total VOCs greater that 1 parts per billion (ppb). Only two reading over 1 ppb were detected (5 and 10 ppb) from soil extracted via macro cores from soil boring and no soil samples were sent to the lab for analysis. The Work To Be Performed Section of the BFA includes the requirement to conduct soil sampling per a DEQ pre-approved work plan to assess potential soil impacts in areas of soil will be disturbed or exposed near future buildings to be constructed. Groundwater No VOCs, SVOCs, or PCB compounds were detected in groundwater samples at concentrations that exceed their respective NC 2L standard. Metals were detected across the site which exceed their respective NC 2L standard. Iron was detected from 950 to 7,100 µg/L (2L=300); manganese from 2,500 to 8,500 µg/L (2L=50); and vanadium at 24 µg/L (2L=0.3) No evidence exists that the compounds were released from operations on the Brownfields Property as dyes were not known to have ever been used. Surface Water and Stream Sediment Surface water and sediment in the stream on the eastern portion of the site was sampled and analyzed for pesticides at two separate locations to evaluate potential impacts from the off-site former Coastal Chemical Corporation facility. No pesticides were detected in the surface water or the stream sediment in excess of method reporting limits. Soil Vapor Soil vapor analysis was conducted to evaluate potential vapor intrusion risk from onsite VOCs potentially released from fuel oil tanks used by the cotton mill and planing mill. Contaminants detected above their respective Residential Soil Vapor Screening Level are: benzene (150 µg/m3 VISL=120), 1,3-butadiene (520 µg/m3 VISL=14), ethylbenzene (440 µg/m3 VISL=370) and m&p xylene (1,300 µg/m3). Soil gas contaminant levels will require active vapor mitigation on some of the proposed apartment buildings planned for construction. Any building which overlies a sample location where the hazard index for the sample is greater than 0.2 and less than 0.5 is high enough to be considered a potential VI risk after the slab is emplaced and will require an approved passive vapor barrier in order to avoid post construction confirmatory sub-slab vapor or indoor air sampling. Any building which overlies a sample location where the hazard index for the sample is 0.5 or greater and less than 1.0 is high enough to be considered a potential VI risk after the slab is emplaced and will require an approved passive vapor barrier and post construction confirmatory sub-slab vapor or indoor air sampling. Any building which overlies a sample location with a hazard index of 1.0 or greater will require active vapor intrusion mitigation. Additional information regarding the risks associated with each proposed building are below following the risk calculator for the respective building. Sub-Slab Vapor One sub-slab soil vapor sample was collected in the vicinity of the former boiler and fuel oil tanks. Twelve VOCs were detected, but none were detected above the DWM Residential Soil Gas Vapor Intrusion Screening Levels. Indoor Air Indoor air samples were collected in the crawl space to evaluate the potential for vapor intrusion into the cotton mill building. Four different VOCs were detected at concentrations above those compound’s DWM Residential Indoor Air Vapor Intrusion Screening Levels (VISL), with benzene up to 1.02 g/m3 (VISL=0.36), carbon tetrachloride up to 0.525 g/m3 (VISL=0.47), chloroform at 0.538 g/m3 (VISL=0.47) and ethylbenzene at 1.15 g/m3 (VISL=1.1). TCE was present in the crawlspace air below the VISL at a maximum concentration of 0.176 g/m3 (VISL= 0.42). Risk Calculations Risk Calculations were performed using DWM Risk Calculator (February 2018 version). Separate risk calculations were performed for the former cotton mill and for each proposed new apartment building. The risk calculations for the Brownfields Property are based on available data, including the following media: groundwater, soil vapor, sub-slab soil vapor and indoor (crawlspace) air samples. For DWM, an acceptable carcinogenic risk is considered to be less than 1.0E -04 and an acceptable noncancer hazard index is less than 1.0. Exposure scenarios with unacceptable risk calculation results based on the known contaminants in the media at the Brownfields Property are indicated in the following tables and are signified by a “Yes” in red under the Risk Exceeded column. Other than for the existing former office building, risk decisions regarding each existing and currently proposed building are below the respective risk calculator output. Note: the soil and groundwater risk pathways are all listed as NC (Not Calculated) because no VOCs were detected in the groundwater samples and no soil samples were analyzed for VOCs. Soil sampling for VOCs prior to construction is required in the Work To Be Performed section of the BFA. Soil exposure risk calculations will be conducted at that that time. Summary of Risk Assessment Output Output Form 1A Version Date: February 2018 Basis: November 2017 EPA RSL Table Site ID: Clayton Spinning Mill 22037-18-051 Exposure Unit ID: Cotton Mill Building Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Construction Worker Soil Combined Pathways NC NC NC Soil Combined Pathways NC NC NC Surface Water Combined Pathways*NC NC NC Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 1.5E-06 9.9E-02 NO Indoor Air 1.1E-05 1.7E-01 NO Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 1.2E-07 7.8E-03 NO Indoor Air 2.5E-06 4.1E-02 NO Pathway Source Source Soil NC Source Groundwater NC Source Soil NC Source Groundwater NC 2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed the NC 2B Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a risk- based closure. Protection of Surface Water Exceedence of 2B at POE? Exceedence of 2B at POE? VAPOR INTRUSION CALCULATORS Resident Non-Residential Worker CONTAMINANT MIGRATION CALCULATORS Target POE Concentrations Exceeded? Protection of Groundwater Use Exceedence of 2L at POE? Exceedence of 2L at POE? 1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations. Notes: PRIMARY CALCULATORS Resident Non-Residential Worker User Defined Cotton Mill Building - Crawl space indoor air sample results do not exceed DWM acceptable risk limits. DWM, following EPA vapor intrusion guidance, considers crawl space air as indoor air. Because TCE was detected in the crawlspace air at 0.176 µg/m3 (VISL=0.42) confirmatory sampling of the crawlspace air is warranted to determine if that level rises. Summary of Risk Assessment Output Output Form 1A Version Date: February 2018 Basis: November 2017 EPA RSL Table Site ID: Clayton Spinning Mill 22037-18-051 Exposure Unit ID: SV-03 Building 1 Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Construction Worker Soil Combined Pathways NC NC NC Soil Combined Pathways NC NC NC Surface Water Combined Pathways*NC NC NC Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 2.5E-07 1.1E-02 NO Indoor Air NC NC NC Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 1.9E-08 8.7E-04 NO Indoor Air NC NC NC Pathway Source Source Soil NC Source Groundwater NC Source Soil NC Source Groundwater NC 2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed the NC 2B Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a risk- based closure. Protection of Surface Water Exceedence of 2B at POE? Exceedence of 2B at POE? VAPOR INTRUSION CALCULATORS Resident Non-Residential Worker CONTAMINANT MIGRATION CALCULATORS Target POE Concentrations Exceeded? Protection of Groundwater Use Exceedence of 2L at POE? Exceedence of 2L at POE? 1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations. Notes: PRIMARY CALCULATORS Resident Non-Residential Worker User Defined SV-03 Building 1 – Soil vapor to indoor air risk levels are not sufficiently high to warrant mitigation or monitoring for the potential of vapor build-up under the slab after it is installed. Summary of Risk Assessment Output Output Form 1A Version Date: February 2018 Basis: November 2017 EPA RSL Table Site ID: Clayton Spinning Mill 22037-08-051 Exposure Unit ID: SV-04 Building 2 Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Construction Worker Soil Combined Pathways NC NC NC Soil Combined Pathways NC NC NC Surface Water Combined Pathways*NC NC NC Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 4.5E-05 2.3E+00 YES Indoor Air NC NC NC Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 3.4E-06 1.8E-01 NO Indoor Air NC NC NC Pathway Source Source Soil NC Source Groundwater NC Source Soil NC Source Groundwater NC 2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed the NC 2B Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a risk- based closure. Protection of Surface Water Exceedence of 2B at POE? Exceedence of 2B at POE? VAPOR INTRUSION CALCULATORS Resident Non-Residential Worker CONTAMINANT MIGRATION CALCULATORS Target POE Concentrations Exceeded? Protection of Groundwater Use Exceedence of 2L at POE? Exceedence of 2L at POE? 1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations. Notes: PRIMARY CALCULATORS Resident Non-Residential Worker User Defined SV04 Building 2 – Residential Soil Gas to Indoor Air risk values are sufficiently high to warrant the installation of a vapor mitigation system in this building during construction. Summary of Risk Assessment Output Output Form 1A Version Date: February 2018 Basis: November 2017 EPA RSL Table Site ID: Clayton Spinning Mill 22037-18-051 Exposure Unit ID: SV05 Building 3 Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Construction Worker Soil Combined Pathways NC NC NC Soil Combined Pathways NC NC NC Surface Water Combined Pathways*NC NC NC Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 1.1E-05 4.9E-01 NO Indoor Air NC NC NC Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 8.2E-07 3.9E-02 NO Indoor Air NC NC NC Pathway Source Source Soil NC Source Groundwater NC Source Soil NC Source Groundwater NC PRIMARY CALCULATORS Resident Non-Residential Worker User Defined 2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed the NC 2B Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a risk- based closure. Protection of Surface Water Exceedence of 2B at POE? Exceedence of 2B at POE? VAPOR INTRUSION CALCULATORS Resident Non-Residential Worker CONTAMINANT MIGRATION CALCULATORS Target POE Concentrations Exceeded? Protection of Groundwater Use Exceedence of 2L at POE? Exceedence of 2L at POE? 1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations. Notes: SV-05 Building 3 - The residential soil vapor to indoor air risk were not exceeded, but a residential hazard index of 4.9 E-01 (0.49) is sufficiently high to warrant sub-slab vapor monitoring or indoor air monitoring to evaluate for potential indoor air risks after the building is constructed. Sub-slab vapor monitoring collected over a sufficient enough duration would determine if contaminants collect under the future slab at sufficient concentrations to exceed the soil gas to indoor air risk threshold. In lieu of sub slab sampling, indoor air sampling could be conducted to determine if indoor air is impacted by contaminants potentially collecting under the new slab. Future monitoring would not be required if vapor mitigation measures acceptable to the NCBP are installed when the building is constructed. Summary of Risk Assessment Output Output Form 1A Version Date: February 2018 Basis: November 2017 EPA RSL Table Site ID: Clayton Spinning Mill 22037-18-051 Exposure Unit ID: SV-01 Building 6 Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Construction Worker Soil Combined Pathways NC NC NC Soil Combined Pathways NC NC NC Surface Water Combined Pathways*NC NC NC Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 9.5E-05 3.9E+00 YES Indoor Air 0.0E+00 0.0E+00 NO Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 7.2E-06 3.1E-01 NO Indoor Air 0.0E+00 0.0E+00 NO Pathway Source Source Soil NC Source Groundwater NC Source Soil NC Source Groundwater NC 2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed the NC 2B Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a risk- based closure. Protection of Surface Water Exceedence of 2B at POE? Exceedence of 2B at POE? VAPOR INTRUSION CALCULATORS Resident Non-Residential Worker CONTAMINANT MIGRATION CALCULATORS Target POE Concentrations Exceeded? Protection of Groundwater Use Exceedence of 2L at POE? Exceedence of 2L at POE? 1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations. Notes: PRIMARY CALCULATORS Resident Non-Residential Worker User Defined SV-01 Building 6 - Residential Soil Gas to Indoor Air risk values are sufficiently high to warrant the installation of a vapor mitigation system in this building during construction. Summary of Risk Assessment Output Output Form 1A Version Date: February 2018 Basis: November 2017 EPA RSL Table Site ID: Clayton Spinning Mill 22037-18-051 Exposure Unit ID: SV07 Building 7 Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Construction Worker Soil Combined Pathways NC NC NC Soil Combined Pathways NC NC NC Surface Water Combined Pathways*NC NC NC Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 1.8E-05 8.6E-01 NO Indoor Air NC NC NC Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 1.4E-06 6.9E-02 NO Indoor Air NC NC NC Pathway Source Source Soil NC Source Groundwater NC Source Soil NC Source Groundwater NC 2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed the NC 2B Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a risk- based closure. Protection of Surface Water Exceedence of 2B at POE? Exceedence of 2B at POE? VAPOR INTRUSION CALCULATORS Resident Non-Residential Worker CONTAMINANT MIGRATION CALCULATORS Target POE Concentrations Exceeded? Protection of Groundwater Use Exceedence of 2L at POE? Exceedence of 2L at POE? 1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations. Notes: PRIMARY CALCULATORS Resident Non-Residential Worker User Defined SV-07 Building 7 - The residential soil vapor to indoor air risk were not exceeded, but a residential hazard index of 8.6 E-01 (0.86) is sufficiently high to warrant sub-slab vapor monitoring or indoor air monitoring to evaluate for potential indoor air risks after the building is constructed. Sub-slab vapor monitoring collected over a sufficient enough duration would determine if contaminants collect under the future slab at sufficient concentrations to exceed the soil gas to indoor air risk threshold. In lieu of sub slab sampling, indoor air sampling could be conducted to determine if indoor air is impacted by contaminants potentially collecting under the new slab. Future monitoring would be required to confirm the performance of vapor mitigation measures employed. Summary of Risk Assessment Output Output Form 1A Version Date: February 2018 Basis: November 2017 EPA RSL Table Site ID: Clayton Spinning Mill 22037-18-051 Exposure Unit ID: SV09 Building 8 Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Construction Worker Soil Combined Pathways NC NC NC Soil Combined Pathways NC NC NC Surface Water Combined Pathways*NC NC NC Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 6.3E-06 3.9E-01 NO Indoor Air NC NC NC Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 4.8E-07 3.1E-02 NO Indoor Air NC NC NC Pathway Source Source Soil NC Source Groundwater NC Source Soil NC Source Groundwater NC 2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed the NC 2B Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a risk- based closure. Protection of Surface Water Exceedence of 2B at POE? Exceedence of 2B at POE? VAPOR INTRUSION CALCULATORS Resident Non-Residential Worker CONTAMINANT MIGRATION CALCULATORS Target POE Concentrations Exceeded? Protection of Groundwater Use Exceedence of 2L at POE? Exceedence of 2L at POE? 1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations. Notes: PRIMARY CALCULATORS Resident Non-Residential Worker User Defined SV-09 Building 8 - The residential soil vapor to indoor air risk were not exceeded, but a residential hazard index of 3.9 E-01 (0.39) is sufficiently high to warrant sub-slab vapor monitoring or indoor air monitoring to evaluate for potential indoor air risks after the building is constructed. Sub-slab vapor monitoring collected over a sufficient enough duration would determine if contaminants collect under the future slab at sufficient concentrations to exceed the soil gas to indoor air risk threshold. In lieu of sub slab sampling, indoor air sampling could be conducted to determine if indoor air is impacted by contaminants potentially collecting under the new slab. Future monitoring would not be required if vapor mitigation measures acceptable to the NCBP are installed when the building is constructed. Summary of Risk Assessment Output Output Form 1A Version Date: February 2018 Basis: November 2017 EPA RSL Table Site ID: Clayton Spinning Mill - 22037-18-051 Exposure Unit ID: SV02 - Phase II Residential Bldg Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Soil Combined Pathways NC NC NC Groundwater Combined Pathways*NC NC NC Construction Worker Soil Combined Pathways NC NC NC Soil Combined Pathways NC NC NC Surface Water Combined Pathways*NC NC NC Receptor Pathway Carcinogenic Risk Hazard Index Risk exceeded? Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 1.1E-06 2.9E-02 NO Indoor Air 0.0E+00 0.0E+00 NO Groundwater to Indoor Air NC NC NC Soil Gas to Indoor Air 8.5E-08 2.3E-03 NO Indoor Air 0.0E+00 0.0E+00 NO Pathway Source Source Soil NC Source Groundwater NC Source Soil NC Source Groundwater NC PRIMARY CALCULATORS Resident Non-Residential Worker User Defined 2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed the NC 2B Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a risk- based closure. Protection of Surface Water Exceedence of 2B at POE? Exceedence of 2B at POE? VAPOR INTRUSION CALCULATORS Resident Non-Residential Worker CONTAMINANT MIGRATION CALCULATORS Target POE Concentrations Exceeded? Protection of Groundwater Use Exceedence of 2L at POE? Exceedence of 2L at POE? 1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations. Notes: SV-02 Phase II residential building - Residential Soil Gas to Indoor Air risk values are not sufficiently high to warrant the installation of a vapor mitigation system in this building during construction. Required Land Use Restrictions: Based on the site-specific data provided to the Brownfield program, the site reuse is suitable for the Brownfields Property as long as the agreed upon land use restrictions in the BFA are abided by. Land use restrictions will include the standard vapor intrusion mitigation system provision, Environmental Management Plan, groundwater, soil disturbance, monitoring well abandonment / replacement, and known contaminants LURs. Based on the site-specific data provided to the Brownfield program, the Brownfields Property is suitable for the proposed reuses as long as the agreed upon land use restrictions in the BFA are abided by. Potential concerns for the Brownfields Property Management Unit (Post Rec Unit): While the sample data from the indoor air in the crawlspace did not exceed a HI of 1 or a LICR greater than 1.0E-4, venting of the crawlspace with a power fan will be needed to ensure contaminant levels in the crawlspace remain satisfactory. Indoor air sampling in the former cotton mill office building may be warranted. Soil sampling for VOCs prior to construction is required in the Work To Be Performed section of the BFA. Post-construction soil sampling is warranted in areas of potential exposure to soil.