More than 50 townspeople came to Town Hall on November 12 to learn more about the history, status, and future of the W.R. Grace Superfund Site along the southeastern edge of Acton. The timing of the Open House followed upon the recent release of the Sixth Five-yearly report, a review of data aimed at assessing whether the clean-up remedy is functioning as intended, the assumptions that went into the design of the remedy are still valid, and if any other information has come to light that could call into question the protectiveness of the remedy.
Question-askers from the community were out in force, including representatives from the Acton Water District, the Acton Select Board and Board of Health, the Water Resource Advisory Board, Green Acton Water Committee, and Concord CREW (Citizens Research & Environmental Watch). Question-answerers in attendance included Kara Nierenberg, Remedial Project Manager and Brenda Murcia, Community Involvement Coordinator, both from the federal Environmental Protection Agency (EPA); Janet Waldron, Section Chief Federal Grants Program, from the Massachusetts Department of Environmental Protection (MassDEP); Tony Penfold, Program Manager, and Victoria Miske, Environmental Specialist, both from site owner W.R.Grace; and Maryellen Johns, project coordinator from de maximis, inc., W.R.Grace’s contractor.
W.R.Grace is a company that makes specialty chemicals and materials. According to an October 2024 fact sheet shared at the Open House, Grace acquired the site spanning the Acton/Concord town line in 1954. They used the site to make concrete additives, organic chemicals, container sealing compounds, latex products, and paper and plastic battery separators. Wastes from these operations were discharged into unlined lagoons or buried in landfills onsite, contaminating soil, sediment and groundwater.
The Open House began with a welcome and introduction by Kara Nierenberg, EPA’s remedial program manager. She briefly explained the history of the site, including the now-completed phase of work to remove the contaminated soil and sediment, and the still-ongoing phase of work to remediate the polluted groundwater. Ongoing groundwater work involves pumping and treating groundwater in one part of the site, and allowing natural attenuation to gradually break down the pollutants in the rest of the site. Progress is monitored by collecting and analyzing samples from monitoring wells across the entire site. In general, the level of the monitored contaminants in the groundwater has been going down, except for one well cluster (OSA-13) in the former lagoon area where levels of volatile organic compounds (VOCs) are increasing; further investigations are planned for that area.
Nierenberg’s presentation was followed by a lively Q&A session. After that the participants had an extended opportunity to scrutinize posters showing data, timeline, actions, and recommendations from the 5-year review, and to converse informally with the site experts.
One topic of high interest was the status of the groundwater in the privately-owned properties surrounding the Superfund Site. In 2023, the Acton Board of Health updated a moratorium on any well drilling within 500 feet of the outer edge of the pollution plume for the monitored contaminants, as shown by the purple line on the map below. Well-drilling could pull up contaminated water, or could change groundwater flows in a way that could disturb the remediation process. The Acton Health Department enforces this moratorium through the town’s well-permitting process. An Open House attendee asked whether there was a program to compensate property owners for the damage to their groundwater. The answer was no.
Another topic of high interest at the Open House was what the future will bring to the site. The most immediate development will be the installation of a 5-megawatt solar array, nestled into the angle between the MBTA commuter rail tracks and the Concord town line (see image below). Site clearing for this project is happening this month, and project completion is scheduled for summer 2025. A housing development had been proposed for the westernmost sliver of the Grace-owned land, fronting onto Parker Street. This project was presented to the town in February 2021 (video), but that developer has apparently dropped this idea because of a lack of wastewater disposal capacity.
As to when the remediation work will be finished, the 5-year review report notes that when the groundwater Record of Decision was finalized in 2005, the remediation of the aquifer to potable/domestic use was projected to take 26 years, which would have placed the completion date in 2031. However, as Ms. Nierenberg stated at the Open House, groundwater remediation is notoriously slow. EPA is still trying to figure out the source of the problem at the well cluster where contaminant levels have been on the upswing. The report (p.25) says, “…it is unclear if that [remediation goal on that time schedule] is attainable.”
Kim Kastens is a volunteer writer, editor, and Board member for the Acton Exchange. In addition, she chairs the Green Acton Water Committee.