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Home My WebLink About22001 3rd Quarterly Vacuum Reading Letter Report 202205313rd Quarterly Post-Occupancy Vacuum Readings Letter Report South Graham Tower Brownfields Project No.: 22001-18-060 ECS Project No.: 49:13566 May 31, 2022 1 May 31, 2022 Mr. Bill Schmithorst NC Department of Environmental Quality Division of Waste Management Brownfields Program Reference: 3rd Quarterly Post-Occupancy Vacuum Readings Letter Report South Graham Tower 401 South Graham Street Charlotte, Mecklenburg County, North Carolina Brownfields Project No. 22001-18-060 ECS Project No. 49:13566 Dear Mr. Schmithorst: ECS Southeast, LLP (ECS) has completed the Third Post-Occupancy Vacuum Readings Letter Report for the above referenced site. These readings were collected in accordance with the Vapor Intrusion Mitigation System Design Submittal, dated July 3, 2019, and prepared by S&ME, Inc., which was approved by the North Carolina Department of Environmental Quality (NCDEQ) Division of Waste Management (DWM) – North Carolina Brownfields Program (NCBP) in an August 7, 2019, email; and as discussed in ECS’ Post Construction/Pre-Occupancy Sampling Report dated September 13, 2021. On February 17, March 9, and April 8, 2022, ECS personnel collected vacuum readings at the measuring points MP-3 through MP-15. The readings are presented on the attached Table 1. As can be seen, the readings collected are greater than the minimum vacuum reading threshold of 0.016 inches of water, with the exception of the readings collected from measuring point MP-13 which were all below the threshold. It should be noted that MP-13 is located in the area where construction activities and repairs were conducted, and it appears that MP-13 was damaged and is no longer a reliable vacuum measuring point. Additionally, in S&ME’s Vapor Intrusion Mitigation System Repair and Blower Replacement letter, dated August 2, 2021, S&ME stated, “Based on the vacuum readings of the other points, we [S&ME] conclude that the system is operating properly, and that Monitoring Point 13 is obstructed and is not registering actual vacuum being imposes at the sample location”. According to the letter from S&ME, it appears that even though this monitoring point is damaged, it does not affect the validity of the remaining measuring points or the Vapor Intrusion Mitigation System. ECS will continue to collect monthly vacuum readings at the site in accordance with the approved Vapor Intrusion Mitigation System Design Submittal, and will submit an additional letter report updating the status of the vacuum readings following the July 2022 measuring event. Please note that the July 2022 quarterly report is the last currently required quarterly monitoring event. Should the three remaining vacuum reading events remain to indicate that the system is operating as designed, 401 South Graham Owner, LLC (the 3rd Quarterly Post-Occupancy Vacuum Readings Letter Report South Graham Tower Brownfields Project No.: 22001-18-060 ECS Project No.: 49:13566 May 31, 2022 2 Property Owner) will likely request to cease the monthly collection and quarterly reporting of vacuum measurements. ECS appreciates the opportunity to provide this report to you on this project. If you have any questions concerning this report or this project, please contact us. Sincerely, ECS SOUTHEAST, LLP Scott Young, P.G. Roger A. Smith, P.G. Environmental Project Manager Principal Geologist 704-525-5152 704-525-5152 syoung1@ecslimited.com rsmith3@ecslimited.com NC Corporate Geology License #C-553 Cc: Mr. Joe Murray, Dominion Realty Partners Ms. Mary Katherine Stukes, Moore & Van Allen Attachment: Table 1 – Monthly Post-Occupancy Vapor Mitigation System Vacuum Readings Table 1 Monthly Post-Occupancy Vapor Mitigation System Vaccum Readings MLK and Graham Tower 401 South Graham Street Charlotte, Mecklenburg County, North Carolina ECS Project No.: 49:13566 Sample Point ID Measurement Date Vacuum Measurement (in H2O) 08/17/21 0.169 09/09/21 0.135 10/14/21 0.124 11/30/21 0.143 12/17/21 0.132 01/26/22 0.131 02/17/22 0.128 03/09/22 0.149 04/08/22 0.150 08/17/21 0.185 09/09/21 0.168 10/14/21 0.146 11/30/21 0.160 12/17/21 0.162 01/26/22 0.145 02/17/22 0.147 03/09/22 0.168 04/08/22 0.178 08/17/21 2.207 09/09/21 2.171 10/14/21 2.187 11/30/21 2.308 12/17/21 2.272 01/26/22 2.268 02/17/22 2.293 03/09/22 2.334 04/08/22 2.346 08/17/21 0.119 09/09/21 0.125 10/14/21 0.123 11/30/21 0.086 12/17/21 0.102 01/26/22 0.079 02/17/22 0.102 03/09/22 0.088 04/08/22 0.107 08/17/21 0.201 09/09/21 0.176 10/14/21 0.161 11/30/21 0.170 12/17/21 0.174 01/26/22 0.166 02/17/22 0.155 03/09/22 0.183 04/08/22 0.191 MP-5 MP-4 MP-3 MP-7 MP-6 Table 1 Monthly Post-Occupancy Vapor Mitigation System Vaccum Readings MLK and Graham Tower 401 South Graham Street Charlotte, Mecklenburg County, North Carolina ECS Project No.: 49:13566 Sample Point ID Measurement Date Vacuum Measurement (in H2O) 08/17/21 0.903 09/09/21 0.848 10/14/21 0.795 11/30/21 0.802 12/17/21 0.786 01/26/22 0.781 02/17/22 0.771 03/09/22 0.773 04/08/22 0.784 08/17/21 0.202 09/09/21 0.176 10/14/21 0.157 11/30/21 0.159 12/17/21 0.172 01/26/22 0.159 02/17/22 0.154 03/09/22 0.183 04/08/22 0.173 08/17/21 0.483 09/09/21 0.443 10/14/21 0.414 11/30/21 0.417 12/17/21 0.417 01/26/22 0.387 02/17/22 0.397 03/09/22 0.436 04/08/22 0.415 08/17/21 0.155 09/09/21 0.119 10/14/21 0.157 11/30/21 0.054 12/17/21 0.080 01/26/22 0.024 02/17/22 0.082 03/09/22 0.061 04/08/22 0.056 08/17/21 0.169 09/09/21 0.126 10/14/21 0.157 11/30/21 0.022 12/17/21 0.079 01/26/22 0.030 02/17/22 0.089 03/09/22 0.042 04/08/22 0.570 MP-12 MP-11 MP-10 MP-9 MP-8 Table 1 Monthly Post-Occupancy Vapor Mitigation System Vaccum Readings MLK and Graham Tower 401 South Graham Street Charlotte, Mecklenburg County, North Carolina ECS Project No.: 49:13566 Sample Point ID Measurement Date Vacuum Measurement (in H2O) 08/17/21 0.011 09/09/21 0.003 10/14/21 0.002 11/30/21 0.003 12/17/21 0.011 01/26/22 0.002 02/17/22 0.003 03/09/22 0.006 04/08/22 0.005 08/17/21 0.151 09/09/21 0.122 10/14/21 0.153 11/30/21 0.024 12/17/21 0.066 01/26/22 0.085 02/17/22 0.069 03/09/22 0.033 04/08/22 0.047 08/17/21 0.149 09/09/21 0.118 10/14/21 0.151 11/30/21 0.033 12/17/21 0.074 01/26/22 0.025 02/17/22 0.083 03/09/22 0.048 04/08/22 0.051 Notes: in H20 = inches of water NC = Not Collected Values in RED indicate readings below 0.016" WC threshold MP-15 MP-14 MP-13