National Grid’s Remediation Contractor and Project Team continued to plan for the third phase (Phase 3) of the 120-foot deep dense non-aqueous phase liquid (DNAPL) Migration Barrier Wall installation. Phase 3 will consist of the installation of a deep jet grouted barrier wall to complete the 120-foot deep Composite DNAPL Migration Barrier Wall Installation.

Maintenance of the decontamination areas, work zones, on-site gravel access roads, parking areas and material staging areas, imported backfill material (i.e., clean fill), stockpile covers, the perimeter privacy screen, 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 October 18, 2010 through October 24, 2010, six fixed base CAMP units and one portable CAMP unit were in-use and measured total volatile organic compounds (TVOC) and particulates (PM10). Fifteen-minute averages for both TVOC and PM10 data remained in the Operational Condition during work activities. There were no elevated readings for TVOC or PM10 for the 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 October 25, 2010 through October 29, 2010, cap system construction activities are scheduled to continue. Dust suppression activities will be conducted, as necessary. Site maintenance activities and CAMP operation monitoring activities will continue, as necessary. The specialty contractor procurement for the 120-foot deep Composite DNAPL Migration Barrier Wall Installation is scheduled to continue.