PFAS, per- and polyfluoroalkyl substances

PFAS are a broad group of manmade chemicals used for a wide variety of purposes. Used since the 1950s, these compounds are in fire-fighting foams, clothing, flame retardants, food packaging, water proofing materials, and carpeting to name a few. These compounds, of which there are reportedly thousands, are structurally and chemically different from each other but share certain properties such as very strong carbon-fluoride bonds that make them very durable in that they do not readily breakdown in the environment, are not affected by natural biological processes, and can persist for years.

Some of these compounds were first detected in our water during the fall of 2019. Further tests conducted in 2020 have confirmed the presence of these chemicals in varying amounts. We now test for 18 of these compounds on a monthly basis. For detailed testing results please visit our water quality site at

MassDEP promulgated new regulations concerning PFAS which took effect in October 2020. 

On June 15, 2022, EPA issued new lifetime health advisories for four PFAS compounds.  The advisory publishes a level for each compound below which no adverse health effects are anticipated based on the best available science.  The new advisories are as follows:

PFOS - 0.02 parts per trillion.  This compound is regularly found in our water.  Over the past several years it has averaged 3.1 parts per trillion with a maximum of 7.2 parts per trillion.

PFOA - 0.004 parts per trillion.  This compound is also found in our water on a routine basis.  It has averaged 5.5 parts per trillion with a maximum of 13.6 parts per trillion.

PFBS - 2000 parts per trillion.  Also routinely found in our water with an average concentration of 2.0 parts per trillion.

GenX (HFPO-DA) - 10 parts per trillion.  This compound has not been detected in our water.

EPA's previous advisory for PFOS/PFOA was 70 parts per trillion, individually and combined so the new advisory levels are a very dramatic change.  The detection limit for these four compounds is approximately 1.7 parts per trillion.  The new PFOS/PFOA levels are far below our current ability to detect.

This has been a moving target but has decreased over the last several years.  The first testing for PFAs was done by the USEPA as part of their Unregulated Contaminant Monitoring Rule #3 (UCMR3).  From 2013-2015, they tested a cross section of public water supplies accross the country to see how common PFAS is in drinking water.  Topsfield was selected to participate in the study and both of our sources were tested twice during 2014.  No PFAS compounds were detected.

As a result of the UCMR3 tests and emerging scientific evidence, USEPA created a health advisory in 2016 for two chemicals - PFOA & PFOS.  The combined total of these compounds shouldn't exceed 70 parts per trillion (ppt).  MassDEP announced in January 2019 that they intended to regulate PFAS and published draft regualtions in October of 2019.  The proposed regulations went through a typical review process and public comment period and went into effect on October 1, 2020.

The Town of Topsfield is very pleased to announce the Water Department has received a grant from the Commonwealth of Massachusetts in the amount of $190,000 to evaluate potential removal technologies for per- and polyfluoroalkyl substances (PFAS). The funds will be used to pilot test several PFAS removal processes in our water treatment plant. The study will generate valuable information that is needed for the planning and design of possible plant modifications and allow the Town to make informed decisions concerning the costs and benefits of PFAS removal.

MassDEP's new PFAS regulations went into effect on October 1, 2020.  The average of our October and November tests exceeded the MCL of 20 nanograms per Liter.  This did not constitute a violation because the quarterly average needs to exceed 20 ng/L.  Preliminary results from December indicate the quarterly result is below the MCL. 

However, the regulations require we mail a letter to residents notifying them of the levels that were found.  Click here to view a copy of the letter. HTML version follows.

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