Location: Hanscom Air Force Base, Massachusetts
Scope: Sites 1, 2, and 3 In Situ Chemical Oxidation/Enhanced Reductive Dechlorination (ISCO/ERD) Injection Program at Operable Unit 1 (OU-1)
Remedial action (RA) activities and associated performance monitoring/reporting (PMR) activities are being conducted at Installation Restoration Program (IRP) Site 1 (FT001), Site 2 (WP012), and Site 3 (WP011), collectively Operable Unit 1 (OU-1), at Hanscom Air Force Base (AFB). The RA activities are intended to supplement existing remedial measures at OU-1 and maintain compliance with the approved remedy described in the OU-1 2007 Record of Decision (ROD). This work is being done as contracted with AFCEC under a Performance-Based Remediation (PBR) Contract with a 7.5-year period of performance (POP) beginning in 2012. RA activities were initially performed at the sites from September 2014 - January 2015. Field activities included ISCO injections at Site 1, and at Sites 2 and 3, they included emulsified vegetable oil and microbe injections (BAC-9) placed in existing wells, newly installed injection wells, and at direct injection points to reduce VOC concentrations in groundwater.
Baseline and post-injection groundwater sampling events occurred at all sites to monitor the effectiveness of remedial treatment and determine if an adjustment of the remedial approach would be required. Additional remedial activities were performed at the sites through June 2017. Two post-injection groundwater sampling events occurred at all three sites to monitor the effectiveness of the remedial treatment. Additional ERD injections were performed in October 2018 for Sites 2 and 3. Under the Long-Term Monitoring Program (LTMP) for OU-1 as specified in the ROD, 52 locations are sampled annually (and water elevations are measured quarterly). The annual LTMP sampling event, in conjunction with the injection PMR events are used to evaluate the effectiveness of the remedial activities at Sites 1, 2, and 3. Data validation is performed for all laboratory results. Annual LTM reports are prepared and submitted to AFCEC, Massachusetts Department of Environmental Protection (MassDEP) and United States Environmental Protection Agency (USEPA) describing the results of the sampling and the effectiveness of the remedial measures.