Carlisle Oversight Committee Questions Groundwater Monitoring Near Concord Town Line

CARLISLE — March 6, 2026 — Carlisle's 2229 Main Street Oversight Committee raised concerns about gaps in groundwater monitoring and debated public outreach strategy ahead of an April 2 EPA town-hall meeting. At its March 6 session, the committee reviewed Green Acton's written comments on the site's annual groundwater monitoring report, which flagged that the 1,4-dioxane plume in the bedrock aquifer has developed a northerly "toe" trending toward Concord, constrained by well MWBS32 — which recorded 26.6 micrograms per liter in April 2025, up from 8.8 the prior year — with no monitoring wells to the north or northeast to bound the plume's actual extent. Green Acton's Kim Kastens told the committee, "The bedrock plume is not very well constrained and seems to be taking a more northerly path than the overburden plume." The committee also heard that EPA's formal Ready for Reuse designation for the site has slipped to 2031, roughly two years later than prior projections. Members voted 4-0, with one abstention, to approve minutes from October 17, January 9, and February 20 meetings, and agreed to submit written comments on the annual report — requesting additional characterization wells and an explanation of the unusual concentration variability at MWBS32 — before the following week's deadline.