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HomeMy WebLinkAboutDC920075_20220204_FINAL_7_Bloodworth_VI_Assessment_nonDSCAREPORT DATE:February 3, 2022 MAA PROJECT #:021R3943.02 VAPOR INTRUSION ASSESSMENT 7 NORTH BLOODWORTH STREET Raleigh, Wake County, North Carolina ENGINEERING & ENVIRONMENTAL SOLUTIONS PREPARED FOR:PREPARED BY: Andrea Bosquez-Porter 727 W. Hargett Street Raleigh, NC, 27603 Mid Atlantic Associates, Inc. 409 Rogers View Court Raleigh, NC, 27610 TABLE OF CONTENTS 1.0 GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Laboratory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.0 SUMMARY OF FIELD ACTIVITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1 Indoor Air Sample Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.2 Soil Gas Sample Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2.1 Vapor Pin Installation Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2.2 Helium Leak Check Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2.3 Sample Collection Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.0 SUMMARY OF LABORATORY ANALYTICAL RESULTS . . . . . . . . . . . . . . . . . 4 3.1 Indoor Air Sampling Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.2 Soil Gas Sampling Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.3 Risk Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.0 QUALITY ASSURANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5.0 FINDINGS AND CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 DRAWINGS Drawing 1 - Topographic Map Drawing 2 - Sample Location Map TABLES Table 1 - Sampling Summary Table 2 - Constituents Detected in Indoor Air & Soil Gas TABLE OF APPENDICES APPENDIX A - Indoor Air Building Survey and Sampling Form APPENDIX B - Laboratory Analytical Report of Soil Gas and Indoor Air Samples APPENDIX C - Risk Calculations for Soil Gas and Indoor Air 1.0 GENERAL INFORMATION 1.1 Introduction The following table provides a brief summary of the Subject Property. Property Size 0.08 acres Former/ Current Uses Land use at the Subject Property has been confirmed by historical sources back to 1909, when the Subject Property appears to have been developed with one residential structure which reflects present-day configuration.City directories confirm residential use of the Subject Property between 1922 and 1968. City directories indicate the Subject Property has been utilized for commercial office purposes from approximately 1970 through present day. Potential Vapor Intrusion (VI) Sources Historical dry-cleaning operations on the south adjacent property from approximately 1971 through 2012.Previous assessment activities identified perchloroethylene (PCE) and trichloroethylene (TCE) in groundwater along the southern site boundary at concentrations exceeding the applicable vapor intrusion screening levels (VISLs) for groundwater to indoor air. No other constituents were reported in the groundwater at concentrations exceeding the VISLs. Presence of Elevators & Stairwells The Subject Property does not contain an elevator. The flights of stairs at the Subject Property are considered open-air, and are not considered stairwells. Assessment Areas The sub-grade basement is unoccupied. Pertinent Map Attachments A topographic site map is included as Drawing 1. A current site map with sample locations is included as Drawing 2. 1.2 Laboratory Enthalpy Analytical Laboratory (Enthalpy) 800 Capitola Drive, Suite 1 Durham, North Carolina 27713 (919) 850-4392 LELAP Lab ID: 04010 Contact: Mr. David Myers 2.0 SUMMARY OF FIELD ACTIVITIES Mid-Atlantic collected one indoor air sample and two sub-slab soil gas samples. See Table 1 for a summary of sample locations and assessment details. Sampling was performed in general accordance with the Inactive Hazardous Sites Program Guidelines for Assessment and Cleanup of Contaminated Sites (January 2020) and the North Carolina Department of Environmental Quality, Division of Waste Management, Vapor Intrusion Guidance (March 2018). On January 25, 2022, Mid-Atlantic conducted a site reconnaissance to identify potential sources of indoor air contaminants inside the Subject Property.The results of the survey are included in the Indoor Air Building Survey and Sampling Form (Appendix A). Typically this survey is completed 24 hours prior to indoor air sampling; however, Mid-Atlantic completed the survey on the same day of indoor air sampling due to time constraints. During the performance of the survey, latex paints were found inside the space in small quantities (<5 gallons) and not removed. The owner of the property, DFS Investments, LLC, did not indicate recent painting or other activities that may impact indoor air quality in the last 12 months. 2.1 Indoor Air Sample Collection On January 25, 2022, Mid-Atlantic mobilized to the site to collect one indoor air sample from the basement at the Subject Property (IA-1).The sample was collected using a laboratory supplied 6-liter, individually certified, stainless-steel Summa canister and a flow regulator designed to restrict the maximum flow rate to 8-10 mL/min. The intake for the canister was set approximately between 3.5 feet above the floor. The canister used during indoor air sampling activities was confirmed to have retained greater than 90% of its initial volume (>27” Hg) prior to sampling. The canister was left open over an approximately 8-hour period and closed once 8 hours had passed or a vacuum of 10 to 5 inches of mercury (10" to 5"Hg) was achieved. In the 24 hours prior to sampling, the space was used under normal operating conditions. The approximate sample location is shown on Drawing 2. The canister was placed on hold in the laboratory and, following receipt of the subsequent sub-slab soil gas sampling results, taken off hold and analyzed for trichloroethylene (TCE) and tetrachloroethylene (PCE) according to EPA Method TO-15. Vapor Intrusion Assessment 7 North Bloodworth Street Raleigh, North Carolina February 3, 2022 Page 2 2.2 Soil Gas Sample Collection Following the collection of the indoor air sample, Mid-Atlantic collected two sub-slab soil gas samples (SS-1 and SS-2)from beneath the basement floor at the Subject Property.The sample locations were selected to be greater than five feet away from exterior walls, cracks, or seams in the concrete basement floor.The approximate sample locations are shown on Drawing 1. 2.2.1 Vapor Pin Installation Procedures Sub-slab borings were advanced at two locations at the Subject Property to support the installation of vapor pins and collection of sub-slab soil gas samples.To create the sub-slab sampling ports, a rotary-impact drill equipped with a decontaminated spline drill bit was utilized to drill a 5/8-inch diameter hole through the concrete slab. The concrete slab thickness varied from approximately eight to ten inches.Beneath the slab at both sample locations appeared to be red clay. Upon completion of each boring, a vapor sampling probe was established using a new “Vapor Pin™” which utilizes a brass barb fitting with a silicone sleeve to create a seal with the concrete when inserted using an installation/extraction tool. The vapor pin was then fitted with ¼-inch outer diameter Teflon-lined tubing to complete the vapor sampling probe assembly. Subsequent helium leak check and soil gas sampling activities are discussed below in Sections 2.2.2 and 2.2.3, respectively. 2.2.2 Helium Leak Check Procedures A leak check was performed at each probe location using a plastic shroud, helium gas, and a portable helium gas detector after the vapor probe location was allowed to equilibrate for at least 20 minutes. A plastic shroud was placed over the sub-slab vapor probe location and sampling train. A 3-way valve was placed on the probe termination and connected to the sampling apparatus. Helium was introduced into the shroud via tubing from the cylinder, and a grab sample was collected by filling a Tedlar bag using the exhaust port of the purge syringe while purging the sample location of a minimum of three system volumes of air at a rate of approximately 200 mL/min. One system volume was approximately 60 mL, and each location was purged of approximately 600 mL. Helium concentrations of 50,000 to 200,000 parts per million were maintained within the shroud during purging. The results of Mid-Atlantic’s helium leak checks at each sample location are as follows: Sample ID Helium Concentration Under Shroud Helium Concentration in Tedlar Bag SS-1 76,000 PPM 25 PPM SS-2 112,000 PPM 0.0 PPM Vapor Intrusion Assessment 7 North Bloodworth Street Raleigh, North Carolina February 3, 2022 Page 3 Because the helium concentrations detected in the Tedlar bag were less than 10% of the concentration under the shroud during leak testing, the seals around the vapor probe were considered acceptable. 2.2.3 Sample Collection Procedures After performing the helium leak check at the interior sub-slab soil gas sample locations, sub-slab soil gas samples were collected using laboratory supplied, batch-certified, 1-liter, stainless steel canisters at a maximum flow rate of 200 mL/min. The canisters used during sub-slab sampling activities were confirmed to have retained greater than 90% of their initial volume (>27” Hg) prior to sampling. The canisters were left open over an approximately 5-minute period and closed once a vacuum of 5” Hg was achieved. Following sampling activities, the soil gas and indoor air samples were collected by a courier and sent to to Enthalpy Analytical Laboratory Laboratory (Enthalpy) in Durham, North Carolina under proper chain of custody for analysis. The canisters were analyzed in the laboratory for TCE and PCE according to EPA Method TO-15. Once sub-slab activities were completed, the vapor probes were removed from the slab and filled with hydraulic cement. 3.0 SUMMARY OF LABORATORY ANALYTICAL RESULTS 3.1 Indoor Air Sampling Results The laboratory analytical report and chain-of-custody record for the indoor air sample collected on January 25, 2022 are provided in Appendix B and summarized in Table 2. The results of the indoor air sampling activities were compared to the NCDEQ June 2021 Residential and Non-Residential Indoor Air Screening Levels (IASLs).As summarized, TCE was not detected in the indoor air sample above laboratory method detection limits. The indoor air sample exhibited PCE below Residential and Non-Residential IASLs. 3.2 Soil Gas Sampling Results The laboratory analytical report and chain-of-custody record for soil gas samples collected on January 25, 2022 are provided in Appendix B and summarized in Table 2. The results of the soil gas sampling activities were compared to the June 2021 Residential and Non-Residential Soil Gas Screening Levels (SGSLs). As summarized, PCE was detected in both sub-slab soil gas samples at concentrations which exceeded the Residential and Non-Residential SGSL.Soil gas sample SS-1 exhibited TCE at a concentration which exceeded the Residential SGSL, but did not exceed the Non-Residential SGSLs.Concentrations of TCE detected in SS-2 exceeded both Residential and Non-Residential SGSLs.Concentrations of PCE detected in SS-1 and SS-2 also exceeded both the Residential and Non-Residential SGSLs. Vapor Intrusion Assessment 7 North Bloodworth Street Raleigh, North Carolina February 3, 2022 Page 4 3.3 Risk Calculations The Division of Waste Management (DWM) establishes vapor intrusion SGSLs and indoor air IASLs for individual compounds for both Residential and Non-Residential (industrial/commercial) exposure scenarios. The DWM allows a maximum cumulative cancer risk for all carcinogens of 1.0E-4 and a maximum cumulative hazard index of 1 for all non-carcinogens in soil gas and indoor air. Mid-Atlantic compared the sub-slab and indoor air sampling results to the DWM Residential and Non-Residential SGSLs/IASLs then calculated the cancer risk and non-cancer risk hazard quotient for compounds detected above the MDL. Residential and Non-Residential cumulative cancer risk and cumulative non-cancer hazard indexes were then determined for the sub-slab soil gas using the highest detected concentration for each compound in the samples (Appendix C). The cumulative Residential and Non-Residential exposure cancer risk sums and non-cancer hazard indexes for the sub-slab soil gas samples are summarized in the following table: Sub-Slab Soil Gas Risk Calculations Exposure Unit Non-Residential Calculated Carcinogenic Risk Sum Non-Residential Cumulative Non-Carcinogenic Hazard Index Residential Calculated Carcinogenic Risk Sum Residential Cumulative Non-Carcinogenic Hazard Index SS-1 & SS-2 1.1E-5 3.1 1.5E-4 3.9E1 As indicated, the soil gas exposure scenarios exceeded the Residential target cumulative cancer risk, Residential and Non-Residential cumulative non-cancer hazard indexes.Therefore, the indoor air sample was taken off hold and analyzed in the laboratory, with the subsequent cumulative risk calculations discussed below. Residential and Non-Residential cumulative cancer risk and cumulative non-cancer hazard indexes were determined for the indoor air sample using the detected concentration for PCE in sample IA-1. Trichloroethylene was not detected in sample IA-1 above method detection limits, and was not included in the risk calculations since the detection limits were below the IASLs for TCE.. Copies of the Residential and Non-Residential risk calculations are included in Appendix C. The Residential and Non-Residential exposure cancer risk sums and non-cancer hazard indexes for the indoor air sample is summarized in the following table: Vapor Intrusion Assessment 7 North Bloodworth Street Raleigh, North Carolina February 3, 2022 Page 5 Indoor Air Risk Calculations Exposure Unit Non-Residential Calculated Carcinogenic Risk Sum Non-Residential Cumulative Non-Carcinogenic Hazard Index Residential Calculated Carcinogenic Risk Sum Residential Cumulative Non-Carcinogenic Hazard Index IA-1 4.6E-8 1.2E-2 2.0E-7 5.2E-2 As indicated, neither the target cumulative cancer risk of 1.0E-4 nor the target cumulative non-cancer hazard index of 1 were exceeded for the indoor air sample for either corresponding risk scenario. 4.0 QUALITY ASSURANCE Mid-Atlantic filled each laboratory provided Summa canister such that the final vacuum in the canister was greater than 4 inches of mercury. The chain-of-custody was completed and packed with the samples. The Mid-Atlantic field technician returned to the office with the packed boxes which were picked up by an Enthalpy courier. The courier then hand delivered the boxes to the laboratory located in Durham, North Carolina. The laboratory report in Appendix B reports level II QA/QC. 5.0 FINDINGS AND CONCLUSIONS The overall objective of this assessment was to determine if the off-site release of dry-cleaning solvent from the south adjacent property has resulted in a vapor intrusion scenario at the Subject Property. Mid-Atlantic offers the following conclusions based on the results of this assessment as they pertain to the Subject Property: • TCE and PCE were detected in sub-slab soil gas samples at concentrations above their respective DWM Residential and Non-Residential SGSLs; • TCE was not detected in the indoor air sample above laboratory method detection and/or SGSLs; • PCE was detected in the indoor air sample at concentrations above laboratory method detection limits but below IASLs; and • The cancer risk and cumulative non-cancer hazard indexes for the indoor air sample did not exceed the target cancer risk sum of 1.0E-4 nor the target cumulative non-cancer hazard index of 1 for each risk scenario. Based on the data collected during this investigation, vapor intrusion does not appear to be causing an unacceptable risk for the Subject Property. Based on the results of the vapor intrusion assessment, no further investigation is warranted at this time. Vapor Intrusion Assessment 7 North Bloodworth Street Raleigh, North Carolina February 3, 2022 Page 6 DRAWINGS ´ TOPOGRAPHIC SITE MAP7 NORTH BLOODWORTH STREETRALEIGH, NORTH CAROLINA DRAWN BY:DATE: ENG. CHECK: JOB NO: APPROVAL: DRAFTCHECK:GIS NO: DWG NO: REFERENCES: SCALE: NOVEMBER 2021 000R3943.00 2G-R3943.00-11 1. RALEIGH WEST, NC DIGITAL RASTER GRAPHICS, USGS. SCANNED FROM 1:24,000-SCALE WAKE, NC TOPOGRAPHIC MAPS, PUBLISHED 2019, USGS.2. INSET MAP DIGITAL DATA FROM 2002 NATIONAL TRANSPORTATION ATLAS, BUREAU OF TRANSPORTATION STATISTICS, WASHINGTON, D.C. WAKE COUNTY GIS. CONTOUR INTERVAL = 10 FEET 0 500 1,000Feet SITE 1:6,000 GCH §¨¦U70 §¨¦I440 §¨¦I40 §¨¦U64 WAKE AREA SHOWNWITHIN WAKE COUNTY N B L O O D W O R T H S T E EDENTON ST NEW BERN AVE ´ SAMPLE LOCATION MAP7 NORTH BLOODWORTH STREETRALEIGH, NORTH CAROLINA DRAWN BY:DATE: ENG. CHECK: JOB NO: APPROVAL: DRAFTCHECK:GIS NO: DWG NO: REFERENCES: SCALE: FEBRUARY 2022 000R3943.01 2G-R3943.01-22 1. MID-ATLANTIC FIELD NOTES.2. NCONE MAP LATEST ORTHOIMGERY3. SHAPEFILES PROVIDED BY WAKE COUNTY GIS 0 50 100Feet1 inch equals 50 feet GCH Legend #*Sub-Slab and Indoor Air Sample Location !(Sub-Slab Soil Gas Sample Location Subject Property Parcel Boundaries !(SS-1 #*SS-2 & IA-1 TABLES SAMPLE ID SAMPLE DATE SAMPLE TYPE SAMPLE DEPTH IA-1 1/25/2022 Indoor Air 3-4 feet above floor, southern basement interior SS-1 1/25/2022 Soil Gas Directly below slab, northern basement interior SS-2 1/25/2022 Soil Gas Directly below slab, southern basement interior MID-ATLANTIC JOB NO. 021R3943.02 TABLE 1 SAMPLING SUMMARY 7 NORTH BLOODWORTH STREET RALEIGH, NORTH CAROLINA < 0.232 -- -- 0.42 1.8 2.18 -- -- 8.3 35 -- 17.4 701 14 180 --6,004 39,804 280 3,500 Notes: Concentration units; ug/m3 = micrograms per cubic meter NCDEQ = North Carolina Department of Environmental Quality DWM = Division of Waste Management ND = Not Detected -- = Not Applicable Underlined values indicate concentrations exceed Non-Residential Screening Levels Bold values indicate concentrations exceed Residential Screening Levels Tetrachloroethene (PCE) Indoor Air Screening Levels Soil Gas Screening LevelsSoil Gas Indoor Air Tetrachloroethene (PCE) Trichloroethene (TCE) Trichloroethene (TCE) 7 NORTH BLOODWORTH STREET CONSTITUENTS DETECTED IN INDOOR AIR & SOIL GAS TABLE 2 NCDEQ DWM Residential Vapor Intrusion Screening Levels (June 2021) NCDEQ DWM Non- Residential Vapor Intrusion Screening Levels (June 2021) Analyte MID-ATLANTIC JOB NO.: 021R3943.02 RALEIGH, NORTH CAROLINA IA-1 SS-1 SS-2 APPENDIX A - INDOOR AIR BUILDING SURVEY AND SAMPLING FORM APPENDIX B - LABORATORY ANALYTICAL REPORT OF SOIL GAS AND INDOOR AIR SAMPLES Mid-Atlantic Associates, Inc. 409 Rogers View Ct Raleigh, NC 27610 7 N Bloodworth VI Assessment Raleigh, NC Client Project # R3943.02 Analytical Report (0122-116R) EPA Method TO-15 Client Specified TO-15 Target Compound List Enthalpy Analytical, LLC Phone: (919) 850 - 4392 / Fax: (919) 850 - 9012 / www.enthalpy.com 800-1 Capitola Drive Durham, NC 27713-4385 Results EA# 0122-116R Page 3 of 24 Quantitation Report Enthalpy Analytical, LLC Sample Name : SS-1 Sample Info : 0122-116; 500L load; Can #11292 Data File : T2200279.D Dilution : 1 Pressurization Factor : 2.407 Acquisition Date : 2022-01-26 15:37:55 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound oncen ra on (PPBV)(PPBV)(PPBV) oncen ra on (ug/m3)(ug/m3)(ug/m3)Flag * Trichloroethene 3.23 0.0973 0.0842 17.4 0.523 0.453 Internal Standards Response e en on me (min) oncen ra on (PPBV) Flag * 1,4-Difluorobenzene (IS) 1,749,702 14.20 5.16 PASS Chlorobenzene-d5 (IS) 1,239,715 18.46 4.93 PASS (ND) = Not Detected* (J) = Below Calibration Range, (E) = Above Calibration Range, (m) = Manual Integration IS Acce tance Criteria: RT +- 20 sec Res onse +- 40% 0122-116 TO15_Quant_Ambient - v2 EA# 0122-116R Page 4 of 24 Quantitation Report Enthalpy Analytical, LLC Sample Name : SS-1 Sample Info : 0122-116; *20=25 load; Can #11292 Data File : T2200280.D Dilution : 20 Pressurization Factor : 2.407 Acquisition Date : 2022-01-26 16:19:34 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound oncen ra on (PPBV)(PPBV)(PPBV) oncen ra on (ug/m3)(ug/m3)(ug/m3)Flag * Tetrachloroethene 885 1.97 1.68 6,004 13.4 11.4 Internal Standards Response e en on me (min) oncen ra on (PPBV) Flag * 1,4-Difluorobenzene (IS) 1,817,568 14.20 5.16 PASS Chlorobenzene-d5 (IS) 1,457,480 18.46 4.93 PASS (ND) = Not Detected* (J) = Below Calibration Range, (E) = Above Calibration Range, (m) = Manual Integration IS Acce tance Criteria: RT +- 20 sec Res onse +- 40% 0122-116 TO15_Quant_Ambient - v2 EA# 0122-116R Page 5 of 24 Quantitation Report Enthalpy Analytical, LLC Sample Name : SS-2 Sample Info : 0122-116; *10=50mL load; Can #11264 Data File : T2200286.D Dilution : 10 Pressurization Factor : 2.376 Acquisition Date : 2022-01-26 20:45:28 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound oncen ra on (PPBV)(PPBV)(PPBV) oncen ra on (ug/m3)(ug/m3)(ug/m3)Flag * Trichloroethene 130 0.961 0.832 701 5.16 4.47 Internal Standards Response e en on me (min) oncen ra on (PPBV) Flag * 1,4-Difluorobenzene (IS) 1,638,370 14.20 5.16 PASS Chlorobenzene-d5 (IS) 1,260,124 18.46 4.93 PASS (ND) = Not Detected* (J) = Below Calibration Range, (E) = Above Calibration Range, (m) = Manual Integration IS Acce tance Criteria: RT +- 20 sec Res onse +- 40% 0122-116 TO15_Quant_Ambient - v2 EA# 0122-116R Page 6 of 24 Quantitation Report Enthalpy Analytical, LLC Sample Name : SS-2 Sample Info : 0122-116; *50=10mL load (2nd TP); Can #11264 Data File : T2200288.D Dilution : 50 Pressurization Factor : 3.922 Acquisition Date : 2022-01-26 22:08:10 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound oncen ra on (PPBV)(PPBV)(PPBV) oncen ra on (ug/m3)(ug/m3)(ug/m3)Flag * Tetrachloroethene 5,869 8.02 6.86 39,804 54.4 46.6 Internal Standards Response e en on me (min) oncen ra on (PPBV) Flag * 1,4-Difluorobenzene (IS) 1,595,956 14.20 5.16 PASS Chlorobenzene-d5 (IS) 1,283,897 18.46 4.93 PASS (ND) = Not Detected* (J) = Below Calibration Range, (E) = Above Calibration Range, (m) = Manual Integration IS Acce tance Criteria: RT +- 20 sec Res onse +- 40% 0122-116 TO15_Quant_Ambient - v2 EA# 0122-116R Page 7 of 24 Quantitation Report Enthalpy Analytical, LLC Sample Name : IA-1 Sample Info : 0122-116; *0.667=750mL load; Can #1443 Data File : T2200277.D Dilution : 0.667 Pressurization Factor : 1.850 Acquisition Date : 2022-01-26 14:02:10 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound oncen ra on (PPBV)(PPBV)(PPBV) oncen ra on (ug/m3)(ug/m3)(ug/m3)Flag * Trichloroethene ND 0.0499 0.0432 ND 0.268 0.232 Tetrachloroethene 0.321 0.0505 0.0432 2.18 0.342 0.293 Internal Standards Response e en on me (min) oncen ra on (PPBV) Flag * 1,4-Difluorobenzene (IS) 1,723,801 14.19 5.16 PASS Chlorobenzene-d5 (IS) 1,215,795 18.46 4.93 PASS (ND) = Not Detected * (J) = Below Calibration Range, (E) = Above Calibration Range, (m) = Manual Integration IS Acce tance Criteria: RT +- 20 sec Res onse +- 40% 0122-116 TO15_Quant_Ambient - v2 EA# 0122-116R Page 8 of 24 Enthalpy Analytical -- Canister Pressurization Job No. Company Site Can Number 11264 11292 1443 Job 0122-116 0122-116 0122-116 Sample ID SS-2 SS-1 IA-1 CleanDate 06/19/2021 12/21/2021 12/13/2021 LeakCheckDate 06/21/2021 12/20/2021 12/16/2021 LeakCheckAnalyst aamears aamears aamears BlankCheckRef T2102790 T2104852 Y2103925 Weather Station ID 71 71 71 Weather Station Exp. 03/04/2022 03/04/2022 03/04/2022 Transducer ID 3 3 3 Transducer Exp.02/19/2022 02/19/2022 02/19/2022 Can Size (L)1.4 1.4 6 Evac Temp (F)69.2 69.2 69.2 Evac Pbar (mmHg)765.6 765.6 765.6 Evac Gauge (mmHg) -765.6 -765.6 -765.6 Evac Analyst aamears aamears aamears Evac Time 01/26/22 12:17 01/26/22 12:18 01/26/22 12:19 Evac Vol (L)0.000 0.000 0.000 Recd. Temp (F)69.9 69.9 69.9 Recd. Pbar (mmHg)762.8 762.8 762.8 Recd. Gauge (mmHg) -100.0 -109.0 -224.0 Recd Vol (L)1.216 1.200 4.238 P1 Temp (F)69.9 69.9 69.9 P1 Pbar (mmHg)762.8 762.8 762.8 P1 Gauge (mmHg)812.0 811.0 234.0 P1 Analyst aamears aamears aamears P1 Time 01/26/22 13:32 01/26/22 13:31 01/26/22 13:24 P1 Vol (L)2.890 2.889 7.841 P1 DF Override false false false P1 Dilution Factor 2.376 2.407 1.850 Mid 1-2 Temp (F)68.5 Mid 1-2 Pbar (mmHg) 764.8 Mid 1-2 Gauge (mmHg) 245.0 Mid 1-2 Vol (L)1.858 P2 Temp (F)68.5 P2 Pbar (mmHg)764.8 P2 Gauge (mmHg)902.0 P2 Analyst ddaniels P2 Time 01/27/22 09:15 P2 Vol (L)3.068 P2 Dilution Factor 3.922 0122-116 MidAtlantic Associates Inc 7 N Bloodworth WI Assessment-Raleigh, NC Canister Pressurization Report 20210215 Report Printed 1/27/2022 9:16:48 AM EA# 0122-116R Page 9 of 24 Lab QC EA# 0122-116R Page 10 of 24 Quantitation Report Enthalpy Analytical, LLC Sample Name : SS-1 LD Sample Info : 0122-116; *20=25 load; Can #11292 Data File : T2200281.D Dilution : 20 Pressurization Factor : 2.407 Acquisition Date : 2022-01-26 17:01:13 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound oncen ra on (PPBV)(PPBV)(PPBV) oncen ra on (ug/m3)(ug/m3)(ug/m3) % Diff Flag * Tetrachloroethene 929 1.97 1.68 6,299 13.4 11.4 4.8 Internal Standards Response e en on me (min) oncen ra on (PPBV) Flag * 1,4-Difluorobenzene (IS) 1,698,035 14.20 5.16 PASS Chlorobenzene-d5 (IS) 1,372,723 18.46 4.93 PASS (ND) = Not Detected * (J) = Below Calibration Range, (E) = Above Calibration Range, (m) = Manual Integration IS Acce tance Criteria: RT +- 20 sec Res onse +- 40% 0122-116 TO15_Quant_Ambient - v2 EA# 0122-116R Page 11 of 24 Quantitation Report Enthalpy Analytical, LLC Sample Name : Humid Blank #10893 Sample Info : 500mL load; Can #10893 Data File : T2200275.D Dilution : 1 Pressurization Factor : 1.000 Acquisition Date : 2022-01-26 11:17:08 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound oncen ra on (PPBV)(PPBV)(PPBV) oncen ra on (ug/m3)(ug/m3)(ug/m3)Flag * Trichloroethene ND 0.0404 0.0350 ND 0.217 0.188 Tetrachloroethene ND 0.0409 0.0350 ND 0.278 0.237 Internal Standards Response e en on me (min) oncen ra on (PPBV) Flag * 1,4-Difluorobenzene (IS) 1,684,623 14.20 5.16 PASS Chlorobenzene-d5 (IS) 1,272,771 18.46 4.93 PASS (ND) = Not Detected * (J) = Below Calibration Range, (E) = Above Calibration Range, (m) = Manual Integration IS Acce tance Criteria: RT +- 20 sec Res onse +- 40% 0122-116 TO15_Quant_Ambient - v2 EA# 0122-116R Page 12 of 24 QC Summary Report Enthalpy Analytical, LLC Sample Name : 5ppbv TO15 LCS Sample Info : 125mL load; Can #2088; GCMSPrepPg1094 Data File : T2200272.D Dilution : 1 Pressurization Factor : 1.000 Acquisition Date : 2022-01-26 09:01:41 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound Response oncen ra on (PPBV) ag a ue (PPBV) % Recovery Flag Trichloroethene 531,854 4.63 5.06 91.5 PASS Tetrachloroethene 648,648 5.34 5.12 104.4 PASS 0122-116 QC_SUM-v2 EA# 0122-116R Page 13 of 24 Quantitation Report Enthalpy Analytical, LLC Sample Name : 5ppbv TO15 LCS Sample Info : 125mL load; Can #2088; GCMSPrepPg1094 Data File : T2200272.D Dilution : 1 Pressurization Factor : 1.000 Acquisition Date : 2022-01-26 09:01:41 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound oncen ra on (PPBV)(PPBV)(PPBV) oncen ra on (ug/m3)(ug/m3)(ug/m3)Flag * Trichloroethene 4.63 0.0404 0.0350 24.9 0.217 0.188 Tetrachloroethene 5.34 0.0409 0.0350 36.2 0.278 0.237 Internal Standards Response e en on me (min) oncen ra on (PPBV) Flag * 1,4-Difluorobenzene (IS) 1,895,310 14.20 5.16 PASS Chlorobenzene-d5 (IS) 1,391,521 18.46 4.93 PASS (ND) = Not Detected * (J) = Below Calibration Range, (E) = Above Calibration Range, (m) = Manual Integration IS Acce tance Criteria: RT +- 20 sec Res onse +- 40% 0122-116 TO15_Quant_Ambient - v2 EA# 0122-116R Page 14 of 24 QC Summary Report Enthalpy Analytical, LLC Sample Name : 5ppbv TO15 LCS LD Sample Info : 125mL load; Can #2088; GCMSPrepPg1094 Data File : T2200273.D Dilution : 1 Pressurization Factor : 1.000 Acquisition Date : 2022-01-26 09:45:12 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound Response oncen ra on (PPBV) ag a ue (PPBV) % Recovery Flag Trichloroethene 531,217 4.64 5.06 91.8 PASS Tetrachloroethene 650,243 5.39 5.12 105.5 PASS 0122-116 QC_SUM-v2 EA# 0122-116R Page 15 of 24 Quantitation Report Enthalpy Analytical, LLC Sample Name : 5ppbv TO15 LCS LD Sample Info : 125mL load; Can #2088; GCMSPrepPg1094 Data File : T2200273.D Dilution : 1 Pressurization Factor : 1.000 Acquisition Date : 2022-01-26 09:45:12 Instrument Method : TO15-SCN2.M Matrix : AIR Target Compound oncen ra on (PPBV)(PPBV)(PPBV) oncen ra on (ug/m3)(ug/m3)(ug/m3) % Diff Flag * Trichloroethene 4.64 0.0404 0.0350 24.9 0.217 0.188 0.3 Tetrachloroethene 5.39 0.0409 0.0350 36.6 0.278 0.237 1.0 Internal Standards Response e en on me (min) oncen ra on (PPBV) Flag * 1,4-Difluorobenzene (IS) 1,887,353 14.20 5.16 PASS Chlorobenzene-d5 (IS) 1,380,306 18.46 4.93 PASS (ND) = Not Detected * (J) = Below Calibration Range, (E) = Above Calibration Range, (m) = Manual Integration IS Acce tance Criteria: RT +- 20 sec Res onse +- 40% 0122-116 TO15_Quant_Ambient - v2 EA# 0122-116R Page 16 of 24 Narrative Summary EA# 0122-116R Page 17 of 24 Enthalpy Analytical Narrative Summary Company Mid-Atlantic Associates, Inc. Client # 7N Bloodworth VI Assessment; R3943.02 Analyst TDD Job # 0122-116R Parameters EPA Method TO-15 # Samples 3 Canisters Custody Alyssa Miller received the samples on 1/26/22 after being relinquished by Mid-Atlantic Associates, Inc. The samples were received at ambient temperature and in good condition. Prior to, during, and after analysis, the samples were kept under lock with access only to authorized personnel by Enthalpy Analytical, LLC. Analysis The samples were analyzed for trichloroethene (TCE) and tetrachloroethene (PCE) using the analytical procedures in EPA Method TO-15, Determination of Volatile Organic Compounds (VOCs) In Air Collected In Specially-Prepared Canisters And Analyzed by Gas Chromatography /Mass Spectrometry (GC/MS). Upon receipt, the canister pressures were measured and recorded. The canisters were then pressurized with UHP nitrogen and a dilution ratio was calculated for each (See the Canister and Controller Datasheet located in the Results section of this report). The Agilent Technologies Model 7890A, Gas Chromatograph "Tobias" (S/N CN10823053) equipped with a 5973N Inert MSD (S/N US03940689) was used for this analysis. All samples and standards were introduced directly to the analyzer using an Entech 7100A Preconcentrator. Calibration The BFB tune analyses associated with the initial and continuing calibrations met all method acceptance criteria. The initial calibration (T011722A-TO15) met the 30% RSD criteria. The initial calibration verification (ICV) met the 70-130% recovery criteria. The continuing calibrations (CCV) met the 30% difference criteria. Full calibration data is available upon request. Chromatographic Conditions The acquisition method (TO15-SCN2.M) has not been included in this level 2 report, however may be made available upon request. EA# 0122-116R Page 18 of 24 Enthalpy Analytical Narrative Summary (continued) QC Notes All internal standard area (IS) responses and retention time criteria were met for these analyses. The Laboratory Duplicate (LD) analyzed with this data set met the 25% difference criteria for all compounds. The laboratory humid blank associated with the analysis of this sample did not contain any of the target analytes at a concentration greater than 3 times the MDL value. The Laboratory Control Samples (LCSs) met the 70-130% recovery criteria. The samples were analyzed within the 30-day holding time required by the method. Reporting Notes These analyses met the requirements of the TNI Standard. Any deviations from the requirements of the reference method or TNI Standard have been stated above. The results presented in this report are representative of the samples as provided to the laboratory. EA# 0122-116R Page 19 of 24 General Reporting Notes The following are general reporting notes that are applicable to all Enthalpy Analytical, LLC data reports, unless specifically noted otherwise.  Any analysis which refers to the method as “Type” represents a planned deviation from the reference method. For instance a Hydrogen Sulfide assay from a Tedlar bag would be labeled as “EPA Method 16-Type” because Tedlar bags are not mentioned as one of the collection options in EPA Method 16.  The acronym MDL represents the Minimum Detection Limit. Below this value the laboratory cannot determine the presence of the analyte of interest reliably.  The acronym LOQ represents the Limit of Quantification. Below this value the laboratory cannot quantitate the analyte of interest within the criteria of the method.  The acronym ND following a value indicates a non-detect or analytical result below the MDL.  The letter J in the Qualifier or Flag column in the results indicates that the value is between the MDL and the LOQ. The laboratory can positively identify the analyte of interest as present, but the value should be considered an estimate.  The letter E in the Qualifier or Flag column indicates an analytical result exceeding 100% of the highest calibration point. The associated value should be considered as an estimate.  Sample results are presented ‘as measured’ for single injection methodologies, or an average value if multiple injections are made. If all injections are below the MDL, the sample is considered non-detect and the ND value is presented. If one, but not all, are below the MDL, the MDL value is used for any injections that are below the MDL. For example, if the MDL is 0.500 and LOQ is 1.00, and the instrument measures 0.355, 0.620, and 0.442 - the result reported is the average of 0.500, 0.620, and 0.500 - - - i.e. 0.540 with a J flag.  When a spike recovery (Bag Spike, Collocated Spike Train, or liquid matrix spike) is being calculated, the native (unspiked) sample result is used in the calculations, as long as the value is above the MDL. If a sample is ND, then 0 is used as the native amount (not the MDL value).  The acronym DF represents Dilution Factor. This number represents dilution of the sample during the preparation and/or analysis process. The analytical result taken from a laboratory instrument is multiplied by the DF to determine the final undiluted sample results.  The addition of MS to the Sample ID represents a Matrix Spike. An aliquot of an actual sample is spiked with a known amount of analyte so that a percent recovery value can be determined. The MS analysis indicates what effect the sample matrix may have on the target analyte, i.e. whether or not anything in the sample matrix interferes with the analysis of the analyte(s). EA# 0122-116R Page 20 of 24 General Reporting Notes (continued)  The addition of MSD to the Sample ID represents a Matrix Spike Duplicate. Prepared in the same manner as a MS, the use of duplicate matrix spikes allows further confirmation of laboratory quality by showing the consistency of results gained by performing the same steps multiple times.  The addition of LD to the Sample ID represents a Laboratory Duplicate. The analyst prepares an additional aliquot of sample for testing and the results of the duplicate analysis are compared to the initial result. The result should have a difference value of within 10% of the initial result (if the results of the original analysis are greater than the LOQ).  The addition of AD to the Sample ID represents an Alternate Dilution. The analyst prepares an additional aliquot at a different dilution factor (usually double the initial factor). This analysis helps confirm that no additional compound is present and coeluting or sharing absorbance with the analyte of interest, as they would have a different response/absorbance than the analyte of interest.  The Sample ID LCS represents a Laboratory Control Sample. Clean matrix, similar to the client sample matrix, prepared and analyzed by the laboratory using the same reagents, spiking standards and procedures used for the client samples. The LCS is used to assess the control of the laboratory’s analytical system. Whenever spikes are prepared for our client projects, two spikes are retained as LCSs. The LCSs are labeled with the associated project number and kept in-house at the appropriate temperature conditions. When the project samples are received for analysis, the LCSs are analyzed to confirm that the analyte could be recovered from the media, separate from the samples which were used on the project and which may have been affected by source matrix, sample collection, and/or sample transport.  Significant Figures: Where the reported value is much greater than unity (1.00) in the units expressed, the number is rounded to a whole number of units, rather than to 3 significant figures. For example, a value of 10,456.45 ug catch is rounded to 10,456 ug. There are five significant digits displayed, but no confidence should be placed on more than two significant digits. In the case of small numbers, generally 3 significant figures are presented, but still only 2 should be used with confidence. Many neat materials are only certified to 3 digits, and as the mathematically correct final result is always 1 digit less than all its pre-cursors - 2 significant figures are what are most defensible.  Manual Integration: The data systems used for processing will flag manually integrated peaks with an “M”. There are several reasons a peak may be manually integrated. These reasons will be identified by the following two letter designations on sample chromatograms, if provided in the report. The peak was not integrated by the software “NI”, the peak was integrated incorrectly by the software “II” or the wrong peak was integrated by the software “WP”. These codes will accompany the analyst’s manual integration stamp placed next to the compound name on the chromatogram. EA# 0122-116R Page 21 of 24 Sample Custody EA# 0122-116R Page 22 of 24 EA# 0122-116R Page 23 of 24 This Is The Last Page Of This Report. EA# 0122-116R Page 24 of 24 APPENDIX C - RISK CALCULATIONS FOR SOIL GAS AND INDOOR AIR DEQ Risk Calculator - Vapor Intrusion - Resident Soil Gas to Indoor Air Version Date: June 2021 Basis: May 2021 EPA RSL Table Site ID: 021R3943.02 Exposure Unit ID: SS-1 & SS-2 CAS # Chemical Name: Soil Gas Concentration (ug/m3) Calculated Indoor Air Concentration (ug/m3) Target Indoor Air Conc. for Carcinogens @ TCR = 1E-06 Target Indoor Air Conc. for Non- Carcinogens @ THQ = 0.2 Calculated Carcinogenic Risk Calculated Non- Carcinogenic Hazard Quotient 127-18-4 Tetrachloroethylene 39804 1194.12 1.1E+01 8.3E+00 1.1E-04 2.9E+01 79-01-6 Trichloroethylene 701 21.03 4.8E-01 4.2E-01 4.4E-05 1.0E+01 Cumulative:1.5E-04 3.9E+01 All concentrations are in ug/m3 Output Form 3B Carcinogenic risk and hazard quotient cells highlighted in orange are associated with non-volatile chemicals. Since these chemicals do not pose a vapor intrusion risk, no risk values are calculated for these chemicals. North Carolina DEQ Risk Calculator DEQ Risk Calculator - Vapor Intrusion - Non-Residential Worker Soil Gas to Indoor Air Version Date: June 2021 Basis: May 2021 EPA RSL Table Site ID: 021R3943.02 Exposure Unit ID: SS-1 & SS-2 CAS # Chemical Name: Soil Gas Concentration (ug/m3) Calculated Indoor Air Concentration (ug/m3) Target Indoor Air Conc. for Carcinogens @ TCR = 1E-06 Target Indoor Air Conc. for Non- Carcinogens @ THQ = 0.2 Calculated Carcinogenic Risk Calculated Non- Carcinogenic Hazard Quotient 127-18-4 Tetrachloroethylene 39804 398.04 4.7E+01 3.5E+01 8.4E-06 2.3E+00 79-01-6 Trichloroethylene 701 7.01 3.0E+00 1.8E+00 2.3E-06 8.0E-01 Cumulative: 1.1E-05 3.1E+00 All concentrations are in ug/m3 Output Form 3E Carcinogenic risk and hazard quotient cells highlighted in orange are associated with non-volatile chemicals. Since these chemicals do not pose a vapor intrusion risk, no risk values are calculated for these chemicals. North Carolina DEQ Risk Calculator DEQ Risk Calculator - Vapor Intrusion - Resident Indoor Air Version Date: June 2021 Basis: May 2021 EPA RSL Table Site ID: 021R3943.02 Exposure Unit ID: IA-1 CAS # Chemical Name: Indoor Air Concentration (ug/m3) Target Indoor Air Conc. for Carcinogens @ TCR = 1E-06 Target Indoor Air Conc. for Non- Carcinogens @ THQ = 0.2 Calculated Carcinogenic Risk Calculated Non- Carcinogenic Hazard Quotient 127-18-4 Tetrachloroethylene 2.18 1.1E+01 8.3E+00 2.0E-07 5.2E-02 Cumulative: 2.0E-07 5.2E-02 All concentrations are in ug/m3 Output Form 3C ** - Note that the EPA has no consensus on reference dose or cancer slope factor values for lead, therefore it is not possible to calculate carcinogenic risk or hazard quotient. Lead concentrations are compared to the National Ambient Air Quality Standard of 0.15 μg/m3. Carcinogenic risk and hazard quotient cells highlighted in orange are associated with non-volatile chemicals. Risks are calculated for these values if indoor air concentrations are entered and indoor air screening levels have been established, but it should be noted that detections of these chemicals are likely not associated with vapor intrusion. North Carolina DEQ Risk Calculator DEQ Risk Calculator - Vapor Intrusion - Non-Residential Worker Indoor Air Version Date: June 2021 Basis: May 2021 EPA RSL Table Site ID: 021R3943.02 Exposure Unit ID: IA-1 CAS # Chemical Name: Indoor Air Concentration (ug/m3) Target Indoor Air Conc. for Carcinogens @ TCR = 1E-06 Target Indoor Air Conc. for Non- Carcinogens @ THQ = 0.2 Calculated Carcinogenic Risk Calculated Non- Carcinogenic Hazard Quotient 127-18-4 Tetrachloroethylene 2.18 4.7E+01 3.5E+01 4.6E-08 1.2E-02 Cumulative: 4.6E-08 1.2E-02 All concentrations are in u /3 Output Form 3F ** - Note that the EPA has no consensus on reference dose or cancer slope factor values for lead, therefore it is not possible to calculate carcinogenic risk or hazard quotient. Lead concentrations are compared to the National Ambient Air Quality Standard of 0.15 μg/m3. Carcinogenic risk and hazard quotient cells highlighted in orange are associated with non-volatile chemicals. Risks are calculated for these values if indoor air concentrations are entered and indoor air screening levels have been established, but it should be noted that detections of these chemicals are likely not associated with vapor intrusion. North Carolina DEQ Risk Calculator