The city began testing for PFAS, per- and poly-fluoroalkyl substances, and PFOA, perfluorooctanoic acid, in 2020 with results of less than 2 parts per trillion, which means it was below the detection limit.

These chemicals are being monitored over the next year as a part of the U.S. Environmental Protection Agency’s unregulated contaminant monitoring rule five, or UCMR5, testing, according to the city public works department.

The initial testing returned a “no detect” result in the municipal water supply, according to public works.

Jason Fladland, the city’s water utility branch manager, said the city began the UCMR5 testing in March 2023 that also returned a “no detect” result.

The city will continue quarterly testing for the next year, he said.

According to the Montana Department of Environmental Quality, PFAS are a group of thousands of human-made chemicals that have been used in many consumer and household products since the 1940s, including cookware, food packaging, and stain repellants, as well as some firefighting foams used at airports, fire training areas, emergency response locations and military installations.

PFAS are sometimes called “forever chemicals” because they don’t easily break down and can stay in the environment for long periods of time, according to DEQ.

PFAS were recognized as a chemical of concern in Montana and a working group completed the Montana PFAS Action Plan in 2020.

In 2021, DEQ implemented a limited PFAS monitoring effort to better understand whether the chemicals are present in Montana surface waters with a focus on measuring the prevalence and magnitude of PFAS contamination in a small sample of locations to determine the potential scale of contamination across the state, according to DEQ.

The 2021 report had an overview of monitoring results including selected rivers, streams and lakes in Great Falls, Helena, Billings and Bozeman, according to DEQ.

Malmstrom Air Force Base and the Montana Air National Guard were identified as sites of concern in Great Falls due to fire suppression chemicals.

PFAS compounds were detected in soil, sediment, groundwater, and surface water at Malmstrom during site investigations conducted in October 2016 and May 2017, according to DEQ.

PFAS were also identified at the Montana Air National Guard/Great Falls International Airport during a July 2018 site investigation, according to DEQ.

The 2021 DEQ report for Great Falls include five sampled sites. Sediment sample results at four sites had non-detect values for 28 PFAS and two sediment samples at the Whitmore Ravine at the footpath bridge site had detections of two PFAS, according to DEQ.

Surface water sample results at one site reported non-detects values for all 28 PFAS and four sites had detections of one or more PFAS. The Whitmore Ravine site was the only location with detections of PFOA and PFOS individually and combined above the screening level of 70 ppt. At Whitmore Ravine, the PFOA and PFOS combined concentration was 1,188 ppt, according to DEQ.

In 2019, Montana DEQ adopted a Human Health standard for PFOA and PFOS individually or combined in groundwater at 70 ppt.

“Since there is no standard for PFAS in surface water to protect human health, this monitoring project used the groundwater standard of PFOA and PFOS individually or combined of 70 ppt as a screening level for surface
water samples,” according to the 2021 DEQ monitoring report.

Montana has no sediment standards for PFAS, and the EPA has no guidance for PFAS in sediment. DEQ used a sediment screening level from Maine’s Department of Environmental Protection Remedial Action Guidelines (RAGs) for contaminated sites. DEQ used the recreation sediment RAG of 4,900 ng/g for PFOS and 4,900 ng/g for PFOA, according to DEQ.

“There is currently no immediate threat to human health, however DEQ recommends the water in Whitmore Ravine not be consumed by people or animals without proper water treatment,” according to DEQ.

Whitmore Ravine is along the south shore of the River’s Edge Trail, toward Rainbow Dam.

“The City of Great Falls Water Treatment Plant treated nearly 4 billion gallons of water to provide drinking water for the citizens of Great Falls in 2022. The plant operated the entire year without violations and met or exceeded all EPA and DEQ water quality requirements. As part of the commitment to providing the residents of Great Falls with safe, quality drinking water, the Water Treatment Plant is regularly undergoing routine testing, maintenance, and upgrades,” Fladland said in a release.

For questions about the quality of the city’s drinking water, contact the Water Treatment Lab at (406) 727-1325 or visit the lab’s website.