Saturday, May 25, 2024

Fresh Pond in Cambridge, seen in 2010. (Photo: Erich via Flickr)

Cambridge is buying its own water testing equipment to detect certain chemicals – substances known as PFAS that forced an expensive, 2.5-month switch to MWRA drinking water this year.

The $700,000 for the Per- and Polyfluoroalkyl Substance testing equipment was freed up Monday by the City Council at the request of the city manager, at the same time it appropriated $4.7 million to pay for the outside drinking water. The city switched from its own reservoir to the Massachusetts Water Resources Authority system between Aug. 30 and Nov. 17 because of the presence of PFAS. Initially, it was expected that Cambridge would be using outside drinking water through the end of the year as it awaited chemical filters held up by supply chain issues.

But when the granular activated carbon filter media arrived last month, installing just two of the total possible six at the Walter J. Sullivan Water Treatment Facility cleared the chemicals to match MWRA quality, City Manager Yi-An Huang said. That meant the city could switch back early.

Four filters have been installed as of Dec. 13. The final two will be installed in time for spring and summer, when water demand increases, deputy city manager and chief operating officer Owen O’Riordan told councillors on Monday.

The city tests for as many as 10 chemical compounds regularly, but those tests have always been outsourced, said Sam Corda, managing director of the Cambridge Water Department. With the new equipment, known as a liquid chromatography tandem mass spectrometer, that testing can continue in-house – but with an advantage.

“Right now, we have only been testing in the reservoirs, but the plan would be to go upstream and identify the source or sources” of chemical infiltration, Corda said.

Cambridge’s water supply comes from city-owned reservoirs at Hobbs Brook, Stony Brook and Fresh Pond, with Hobbs and Stony Brook fed by a 24-square-mile basin in Lexington, Lincoln, Waltham and Weston, according to the department. The area is surrounded by highways and affected by runoff from winter road salting.

“If we do identify some larger points where [chemicals show] higher levels, we would work to remediate those,” Corda said.

Department staff spent several months visiting state-certified PFAS laboratories to find the most accurate and reliable equipment, according to a report from the City Manager’s Office. The equipment it decided on comes with a five-year warrantee and service contract.

“Having the ability to test for PFAS in-house would not only be more cost effective, but allow [the Water Department] to more effectively monitor and react to any changes in PFAS levels throughout the system through more frequent sampling and much shorter turnaround times on test results,” the report said.

Councillor Quinton Zondervan wondered if Cambridge could use its new testing equipment to to help other communities identify PFAS sources. “We are privileged in Cambridge that we can afford to buy our own equipment, but but not everybody can,” Zondervan said.