The town of Mansfield is one of the latest communities tasked with building treatment facilities to address PFAS contamination that is beyond the limit deemed safe by the state.

Cities and towns across the state, and across the country, are faced with the costly challenge of removing the “forever chemicals” (per- and polyfluoroalkyl substances) from public drinking water. In January 2020, the Massachusetts Department of Environmental Protection issued a revised guideline for PFAS in drinking water, setting the limit at 20 parts per trillion.

Testing conducted by Mansfield in 2020 found PFAS levels exceeding MassDEP guidelines in two wells — 22 parts per trillion at the Cate Spring Water Treatment Plant and 22.91 parts per trillion at the Walsh Well Water Treatment Plant. Residents were notified, and Cate Spring was taken out of service except in emergencies, while the pumping rate at Walsh Well was reduced to the minimal amount required to keep the plant in service, according to a notification issued by Mansfield Water Operations Manager Shawn Precourt. The town’s four other active wells tested below the MassDEP guidelines.

Plans for two new treatment facilities were approved at a fall 2020 special town meeting. The $4.54 million Cate Spring project qualified for a American Rescue Plan Act grant of $909,165. A PFAS treatment system for Walsh Well is estimated to cost $4 million. Voters approved additional funds for other water system improvements.

The new facility at Cate Spring, brought online this past June, uses a granular activated carbon filtration system that removes PFAS down to undetectable levels. The water then goes through the normal treatment process at the Cate Spring Water Treatment Plant.

PFAS have been used for decades in the manufacturing of non-stick cookware and other household items and in firefighting foam. These chemicals, while largely phased out of use, are water soluble and remain in the environment because they do not degrade over time, leaving communities grappling with a public health threat.

In July, the U.S. Environmental Protection Agency moved to designate two of the six PFAS chemicals, PFOA and PFOS, as hazardous substances under the Superfund law, which could lead to quicker cleanup of contamination. This followed the issuance of Drinking Water Health Advisories for PFOA and PFOS by the EPA in June that noted “some negative health effects may occur with concentrations of PFOA or PFOS in water that are near zero.”

Under the proposed rule, the “EPA will both help protect communities from PFAS pollution and seek to hold polluters accountable for their actions,’’ EPA Administrator Michael Regan said in a statement.

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