Letter-To-The Editor: Acton Water District Responds to Reports of Potential 1,4-Dioxane Contamination

Editor's Note: The following is a letter sent from the Acton Water District's District Manager Chris Allen to the editors of Acton and Concord Patch, as well as the editor's of the Concord Journal and The Beacon  . 

To The Editors of The Beacon, The Concord Journal, Acton Patch, and Concord Patch:

In the recent online and print articles related to the Nuclear Metals Inc. (NMI) Superfund site, the contention that industrial contamination from the Nuclear Metals (NMI) site at 2229 Main Street in Concord “Could pose a threat to Acton's drinking water” requires context. Unfortunately, none of the reporters reached out to Acton officials prior to publishing the articles and the perspective of the local water supply potentially impacted by this site was not well represented by the officials from the United States Environmental Protection Agency or the 2229 Main Street Committee.

There is a plume of 1,4-dioxane that is migrating under the Assabet River toward the two Assabet well sources, the highest yielding sources managed by the Acton Water District (the District).The District has been monitoring this contaminant for 10 years due to its presence at the W.R. GraceSuperfund site and as part of the Unregulated Contaminant Monitoring Rule. In the past 5 years we have been more aggressively monitoring concentrations of this emerging contaminant. Only in the past 5 years has there been reliable laboratory analysis to detect the extremely low (Parts per Billion (ppb), or, Micrograms per Liter (ug/L)) concentrations of the contaminant. Currently the Massachusetts Department of Environmental Protection (MA DEP) Office of Research and Standards has set a guidance level in drinking water of 0.3 ppb. This value was revised in 2011 from a previous guideline of 3.0 ppb. The scientific analysis and risk assessment of 1,4-dioxane and its impacts on human health remain unclear at this time, but the contaminant is labelled as a “Probable Class B2 Carcinogen”. 

Monitoring for 1,4-dioxane has been widespread throughout that area of the local aquifer due to the combined contamination of the W.R. Grace Superfund site and more recently the NMI Superfund site in Concord. Since the early 1980’s, the District has been effectively filtering raw water from the groundwater sources in these areas for Volatile Organic Compounds found in these industrial contamination plumes using air stripping towers (Where treated water actually enters the distribution piping system network for human consumption). Concentrations of 1,4-dioxane that have been detected at our South Acton Water Treatment Plant (SAWTP) are tabulated here and our compliance with the guideline is based on a running annual average of these results.

For your convenience, we’ve accumulated information relating to 1,4-dioxane on our website. This
can be accessed here http://actonwater.com/water-qu...

Acton residents should be assured that the District takes this emerging contaminant and its impacts on our drinking water very seriously. With the identification of the NMI plume, an environmental consultant and environmental attorney were retained to assist the District in understanding and managing the issues associated with 1,4-dioxane. Additionally, the recently completed SAWTP was designed with treatment flexibility should it be required and a suitable technology can be identified. As with any contaminant in our drinking water supply, if there were ever a severe health impact that required public notification to restrict the use of the water supply, we would take the necessary steps to alert the public accordingly. If you have any questions, or require any additional information, please contact Matthew Mostoller, Environmental Manager at
matt@actonwater.com, or Chris Allen, District Manager at chris@actonwater.com by email, or call the
District’s office at 978-263-9107 Mon-Fri from 7:30 AM to 4:00 PM.

Respectfully submitted,
Chris Allen
District Manager