By Carole Plumb
The Release Abatement Measure (RAM) plan update was presented by Licensed Site Professional, Ben Gould of CMG Environmental, who has overseen remediation activities related to the former Raytheon site since 2002 (Massachusetts Department of Environmental Protection (DEP) Release Tracking Number (RTN) 3-13302).
Excavation work at 8 Andrew Ave for construction of the Council of Aging/ Community Center had uncovered a sealed unknown underground structure contaminated with petroleum products and PFAS, triggering a new RTN 3-50340 and necessitating further groundwater assessment before state reporting deadlines.
Raytheon occupied the 67-acre site from 1955 to 1995, conducting radar testing operations and releasing chlorinated solvents, PCBs, and heavy metals into the soil and wetlands, including the Sudbury River corridor. Mass DEP required decades of phased investigations and remediation, including soil removal, wetland reconstruction, groundwater monitoring, and In situ chemical oxidation (ISCO) treatment by chemical injections to degrade volatile hydrocarbon contaminates.
The current meeting focused on recent activities triggered during construction. On January 30, 2024, contractors uncovered a small underground concrete tank and adjacent piping system. Though initially believed to be a septic system, the tank’s contents included petroleum hydrocarbons and measurable levels of PFAS, specifically PFOS. Soil samples surrounding the structure confirmed contamination, prompting its eventual clean up, removal and disposal as concrete rubble by Tower Construction.
CMG conducted a new round of soil and groundwater sampling under the RAM plan filed in March 2023. Of 4,880 cubic yards of soil excavated during CoA/CC construction, 2,400 cubic yards were determined to be clean enough for reuse at 8 Andrew Ave, while an additional 1,130 cubic yards were moved to 22 Andrew Ave (the Town Green), all within the boundary of Raytheon’s RTN 3-13302. The soil underwent extensive statistical comparison to Massachusetts DEP’s “Similar Soils Provision Guidance,” including checks for PAHs, chlorinated pesticides, and PFAS. No results exceeded DEP action levels.
For groundwater, CMG installed three monitoring wells near the unidentified tank. Preliminary lab results show no exceedances for volatile petroleum hydrocarbons (VPH), extractable petroleum hydrocarbons (EPH), or PCBs. Low detections of PAHs were attributed to suspended silt from underdeveloped wells.
PFAS results from Alpha Analytical are pending and expected soon. If the combined total of six EPA regulated PFAS compounds (PFAS6) remains under 20 parts per trillion, the town can close out the RAM with a Permanent Solution Statement. If not, it must file a Tier Classification and Phase I Site Investigation by June 12 on the 1 year anniversary of Mass DEP 120-Day release notification.
The town is the responsible party for RTN 3-50340, although the contamination originated during Raytheon’s operations. Legal responsibility for long-term liability may fall to Raytheon, but Gould deferred that issue to Raytheon attorneys and Town counsel.
Public comment on the three draft reports RAM Completion, RAM + Permanent Solution, and Phase I Site Investigation is open through June 7. His presentation and reports are available on DEP’s data portal under RTNs 3-13302 and 3-50340, although Gould noted the reports have a significant amount of overlap due to DEP requirements. The final submission will depend on the pending PFAS data.
