Weekly Update Ending: Week July 29, 2011

National Grid Report on MGP site remediation
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National Grid’s Remediation Contractor and Project Team continued to plan for the composite 120-foot deep dense non-aqueous phase liquid (DNAPL) Migration Barrier Wall (i.e., jet grouted barrier) installation. The Remediation Contractor conducted general maintenance activities and housekeeping at the Site. No intrusive remediation construction activities were conducted at the Site.

Maintenance of the imported backfill material (i.e., clean fill) stockpile covers and soil erosion and sediment control (SESC) measures continued. Odor and dust suppression activities were conducted, as necessary. National Grid’s consulting engineers continued to monitor the site activities with the community air monitoring program (CAMP) equipment.

During the period from July 25, 2011 through July 31, 2011, six fixed base CAMP units were in operation and measured total volatile organic compounds (TVOC) and particulates (PM10). Fifteen-minute averages for both TVOC and PM10 data remained in the Operational Condition. There were no elevated readings for TVOC or PM10 for this monitoring period. The Weekly Report that summarizes the CAMP data can be found as a separate tab in the Weekly Report Archive section.

For the week of August 1, 2011 through August 5, 2011, no intrusive remediation construction activities are scheduled at the Site. The Remediation Contractor will conduct general maintenance activities and housekeeping at the Site, as necessary. Dust suppression activities will be conducted, as necessary. CAMP operation monitoring activities will continue. The specialty contractor procurement for the 120-foot deep Composite DNAPL Migration Barrier Wall Installation is scheduled to continue.