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. 

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.

Our water was first tested for PFAS in 2014 as part of US EPA's Unregulated Contaminant Monitoring Rule Part 3.  This program tested a cross section of water supplies across the country for a variety of contaminants to determine the frequency of occurence and the amounts found.  Six PFAS compounds were included in the tests.  The table below shows the minimum reportable level for each compound for the UCRM3 tests and current methods.  The minimum reportable level is the lowest level of the contaminant that can be reliably measured.  Results found below this level are listed as 'non-detectable'.

 Compound  UCMR3 MRL (2014)   Today's MRL (2020)   Average Level Found Today (2019-2020)
PFOS 40 ng/L 1.8 ng/L 7.2 ng/L
PFOA  20 ng/L  1.8 ng/L 12.6 ng/L
PFNA  20 ng/L 1.8 ng/L 0.4 ng/L
PFHxS 30 ng/L 1.8 ng/L 0.8 ng/L
PFHpA 10 ng/L 1.8 ng/L 1.9 ng/L
PFBS 90 ng/L 1.8 ng/L 2.1 ng/L


The tests conducted today are approximately 10 times more sensitive than the tests done in 2014.  

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Water Department

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Topsfield, MA 01983


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Topsfield, MA 01983


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