PFAS Overview

Most Recent PFAS6 Test Results 

Note: The PFAS6 regulatory limit is based on a quarterly average.

What is PFAS?

Per-and polyfluoroalkyl substances (PFAS) are a family of chemicals used since the 1950s to manufacture stain-resistant, water-resistant, and non-stick products.  PFAS are widely used in common consumer products as coatings, food packaging, outdoor clothing, carpets, leather goods, ski and snowboard waxes, and a wide array of consumer and industrial products.  PFAS stays in the environment for a long time and does not break down easily.  As a result, PFAS are widely detected in soil, water, air, and food.  Some PFAS can accumulate in the food chain.  Exposure can occur when someone uses certain products that contain PFAS, eats PFAS-contaminated food, or drinks PFAS-contaminated water.  When ingested, some PFAS can build up in the body, and, over time, these PFAS may increase to a level where health effects could occur.

Why is this important?

Studies indicate that exposure to sufficiently elevated levels of certain PFAS may cause a variety of health effects, including developmental effects in fetuses and infants effects on the thyroid, liver, kidneys, certain hormones, and the immune system. Some studies suggest a cancer risk may also exist in people exposed to higher levels of some PFAS compounds. Scientists and regulators are still working to study and better understand the health risks posed by exposure to PFAS. MassDEP, the state's regulatory agency for drinking water, notes in its fact sheet on PFAS that consuming water with PFAS-6 above the drinking water standard does not mean that adverse effects will occur. The degree of risk depends on the level of the chemicals and the duration of exposure. The drinking water standard assumes that individuals drink only contaminated water, which typically overestimates exposure, and that they are also exposed to PFAS-6 from sources beyond drinking water, such as food. MassDEP is following developments in this burgeoning area closely.

There is some debate in the industry on the level of PFAS in drinking water that may cause health concerns. The EPA has not yet set a regulatory level, but has set a health advisory level of 70 parts per trillion for PFAS. Massachusetts has taken a more cautious stand and set a drinking water standard of 20 parts per trillion for PFAS-6 which is the sum of six common PFAS chemicals.

The Pond Street water treatment plant has periodically popped above the Massachusetts standard, largely in the summer months.  The Beal and Broadway plants have remained below the standard.   All of the Town's test results are listed in the table below.  The most recent PFAS test values are shown at the top of this page.

Treatment Plant Finished Water

Pond Street WTP

Notes

August 2022 samples were rejected by MassDEP due to quality control issues. As a result, third-quarter compliance is based on an average of July and September.

Beal WTP

Broadway WTP

Source Waters (Wells)

Pond Street Well No. 1

Pond Street Well No. 2

Pond Street Well No. 3

Beal Well No. 1

Beal Well No. 2

Broadway Well No. 1

Broadway Well No. 2

Hanover St Well No. 1

Hanover St Well No. 2

Notes

• All values are in ppt (parts per trillion)
• ND* - J-Qualifier is used when the result is below the reportable level but above the minimum detection limit.  The result is considered an estimate.
• ND - Not Detected
• NT - Not Tested
• PFOS - perfluorooctane suflfonic acid
• PFOA - perfluorooctanoic acid
• PFNA - perfluorononanoic acid
• PFDA - perfluorodecnoic acid
• PFHxS - perfluorohexane sulfonic acid
• PFHpA - perfluoroheptanoic acid
• PFAS6 - the sum of PFOS, PFOA, PFNA, PFDA, PFHxS, and PFHpA

Public Notifications

• Quarter 2, 2021
• Quarter 3, 2021
• Quarter 4, 2021
• Quarter 3, 2023

What are we doing to correct the problem?

• The PFAS we are dealing with is the result of groundwater that has been impacted by decades of development in the town and not by our treatment processes. PFAS is being detected now because advancements in testing are now allowing us to detect the PFAS compounds at a much lower level than ever before.  
• We anticipated prior to beginning our testing in April of 2021 that we might be out of compliance given that industry trends to date have been 20-30 percent of supplies tested positive for PFAS. To be proactive, we began interviewing engineering firms in case their services were needed on short notice.
• We have engaged MassDEP. Based upon this engagement, we submitted a draft public education and public notification document based on MassDEP's templates, which they reviewed and approved.  This notice went out to the public on August 18, 2021.
• We have engaged an engineering firm to assist us in developing a solution to the problem.  This firm has experience in reducing PFAS concentrations in other communities.
• We held a public forum on September 15, 2021, in partnership with MassDEP to educate the public about PFAS and to answer questions from the public.  We thank MassDEP for their participation in this forum as it was very informative and many questions were answered.
• The quickest, easiest, and most reasonable solution seems to be to perform a demonstration study on one of the three mixed-media filters at the Pond Street plant, replacing the media with granular activated carbon (GAC). GAC works by adsorbing the PFAS, drawing it out of the water. Our engineers have prepared and on September 17, 2021, submitted a permit application with MassDEP seeking their approval of this demonstration study. If approved, we will replace the existing media with GAC and run for a month to assess performance. The demonstration study will indicate if replacing the media in one or more filters will get the Pond Street WTP water below the state standard. The study will also give an estimate of the lifespan of the GAC filter media. In anticipation of DEP's approval of our plan, we have purchased and received the media needed and are ready to install once we receive approval. 
• If replacing the filter media in the Pond Street WTP is not effective, we will need to design, permit, procure, and build additional external GAC filters at Pond Street. This will necessitate taking the parking lot at the facility and will require the relocation of the DPW offices to some other site.
• On September 21, 2021, MassDEP approved the Town's proposed plan to replace the filter media in one filter at the Pond Street WTP with granular activated carbon (GAC) and to perform a demonstration study on the effectiveness of GAC to reduce PFAS in the Pond Street WTP finished water. Work is expected to commence the week of September 27, 2021.
• From September 28, 2021, to September 30, 2021, DPW personnel removed old filter media from the Pond Street #3 filter, inspected the filter underdrains, and installed new GAC filter media. The work was inspected and approved by our engineers and the filter went into service on October 5, 2021.

Low PFAS Water Spigots

Broadway Water Treatment Plant (Free of Charge)

Since water demand is too high to take the Pond Street WTP offline, we have made spigots available on the front of the Broadway WTP, located at 507 Broadway, where PFAS levels are under the state regulatory limit of 20 ppt (Broadway PFAS results, April: 6.61 ppt, May: 6.46 ppt, July: 8.20 ppt) to provide a source of drinking water for residents who may be concerned by the elevated test results at Pond Street.  These spigots are available free of charge during posted hours (currently 8 am to 8 pm, 7 days a week).   

Broadway Water Treatment Plant

Broadway Sample Station Entrance

Broadway Sample Station

Pilot Study on Granular Activated Carbon Filter

On September 17, 2021, Environmental Partners, Inc. submitted on our behalf an application to MassDEP to replace the existing filter media from Pond Street Water Treatment Plant Filter 3 with granular activated carbon (GAC) and to conduct a study to determine the GAC's filter effectiveness for removing per and poly-fluoroalkyl substances (PFAS). MassDEP granted approval for this study on September 21, 2021 (DEP Approval). Between September 28th and 30th, DPW staff removed the existing filter media and installed the new GAC media to Filter #3. This filter was placed into service on October 5, 2021. In October 2023, the exhausted GAC media was replace with new GAC media. The table below summarizes PFAS6 test results during this time period.     

Pond Street Filter #3

On April 27, 2022, Pond Street Filter #2 was converted to GAC media. Test results on this pilot study are provided in the following table.

Pond Street Filter #2

Notes

On September 26, 2022, Pond Street Filter #1 was converted to GAC media. Test results on this pilot study are provided in the following table.

Pond Street Filter #1

Resources

• Commonwealth of Massachusetts PFAS Interagency Task Force
• EPA's PFAS
• Hanover's Complete PFAS Test Results 
• Massachusetts Waterworks Association, Safewatermass.org Project
• MassDEP's PFAS
• PFAS Point-of-Use Treatment System Study

Questions?

If you have questions, please contact Neal Merritt, Deputy Superintendent of Water Operations, at 781-826-3189.