(PFAS) Perfluoroalkyl Substances 

Please watch the video below for an update on the hexavalent chromium and PFAS piloting work.

In October 2020, the Massachusetts Department of Environmental Protection (MassDEP) established a maximum contaminant level (MLC) for the sum of six PFAS compounds, including PFOA, PFOS, perfluorohexane sulfonate (PFHxS), perfluorononanoic acid (PFNA), perfluorohepatanoic acid (PFHpA), and perfluorodecanoic acid (PFDA). MassDEP refers to the six PFAS compounds as the PFAS6 and has set the MCL for the sum of these at 20 nanograms per liter (ng/L) or parts per trillion (ppt). The Town of Shrewsbury began monitoring for PFAS in a voluntary testing program with MassDEP in the summer of 2019 along with 21 other communities in the Commonwealth. The Town continues to monitor on a regular basis.PFA Image


The Town of Shrewsbury's finished blend water (from multiple well sources) continues to be below the 20 ppt for the sum of the six PFAS compounds. 

Recent lab results for the sum of the six PFAS compounds: 

  • May 2, 2022 - 16.4
  • June 8, 2022 - 17.7 ng/L
  • July 13, 2022 - 10.9 ng/L
  • August 10, 2022 - 16.6 ng/L
  • September 14, 2022 - 17.6 ng/L
  • October 13, 2022 - 16.2 ng/L
  • November 10, 2022 - 12.8 ng/L
  • December 7, 2022 - 11.8 ng/L
  • January 26, 2023 - 10.5 ng/L
  • February 15, 2023 - 11.1 ng/L
  • March 6, 2023 - 13.6 ng/L
  • April 20, 2023 - 13.7 ng/L

The federal Environmental Protection Agency has not yet set an MCL for PFAS but has issued a health advisory of 70 ppt for PFOA and PFOS. 

Next Steps 

PFAS can be removed from drinking water through filtration, which would have to be added to the Town's water treatment system. On March 11, 2021, the Town received final approval from MassDEP to began pilot testing of several different types of media for the removal of PFAS.  With the assistance of the Town's consultant, Tata and Howard, the pilot program began in May 2021 and is expected to conclude in December 2021. Pilot testing involves utilizing small scale filtration equipment to determine which process works best for our water.

Additional Information

What are PFAS? 

Per-and polyfluoroalkyl substances, also known as PFAS, are a group of manmade chemicals that have been manufactured and used in a variety of industries since the 1950s. They are referred to as ‘forever chemicals’ – they are persistent in our bodies and the environment and many will not naturally degrade. PFAS chemicals are most often commercially used to create grease, water and stain resistant barriers for materials, including Teflon, grease-resistant take out containers, and upholstery and carpet treatments; these chemicals are also found in firefighting foam. 

Why are PFAS only recently garnering attention if they have been used since the 1950s? 

In 2016, the United States Environmental Protection Agency published a drinking water Health Advisory level for two PFAS compounds at a combined 70 parts per trillion as the science to test and identify these chemicals has evolved. In 2018, the Massachusetts Department of Environmental Protection (DEP) issued a more stringent drinking water guideline of 70 parts per trillion for five combined PFAS compounds.  

As of April 2019, DEP has proposed amendments to drinking water guidelines, and groundwater and soil cleanup standards to change the limits to 20 parts per trillion for a combined six PFAS compounds. These regulations were implemented in October 2020.


Shrewsbury PFAS in Drinking Water Supply October 17, 2019

Mass DEP Fact Sheet - Per- and Polyfluoroalkyl Substances (PFAS) in Drinking Water: Questions and Answers for Consumers

Massachusetts Department of Public Health- Per- and Polyfluoroalkyl Substances (PFAS) in Drinking Water

Links to additional information

Mass DEP information about PFAS

US EPA information about PFAS

CDC ATSDR information about PFAS

Association of State Drinking Water Administrators PFAS webpage includes information about what other States are doing