PART ONE

The EPA is set to limit PFAS in drinking water to barely detectable levels. Can water utilities meet the standard?

Brian Tarbuck, general manager of the Greater Augusta Utility District, at a test site for PFAS treatment in Augusta, Maine this January. Visual: Michael G. Seamans for Undark

SITUATED IN A former sand and gravel pit just a few hundred feet from the Kennebec River in central Maine, the Riverside Station pumps half a million gallons of fresh groundwater every day. The well station processes water from two of five wells on either side of the river operated by the Greater Augusta Utility District, or GAUD, which supplies drinking water to nearly 6,000 local households. Most of them reside in Maine’s state capital, Augusta, just a few miles to the south. Ordinarily, GAUD prides itself on the quality of its water supply. “You could drink it out of the ground and be perfectly safe,” said Brian Tarbuck, GAUD’s general manager.

But in March 2021, environmental sampling of Riverside well water revealed trace levels of per- and polyfluoroalkyl substances (PFAS), or “forever chemicals,” as they’re better known. The levels at Riverside didn’t exceed Maine’s drinking water standard of 20 parts per trillion (ppt), which was a relief, Tarbuck said. Still, he and his colleagues at the utility were wary. PFAS have been linked to a variety of health problems, and Maine lawmakers at the time were debating an even stricter limit for the chemicals. Tarbuck knew a lower standard was coming someday. The only question was when.

As it turns out, a tougher standard is expected early this year. That’s when the U.S. Environmental Protection Agency is set to finalize an enforceable cap on PFAS in drinking water that will require GAUD and thousands of other utilities around the country to update their treatment methods. The standard, which in regulatory terms is called a maximum contaminant level or MCL, limits permissible amounts of the two most studied and ubiquitous PFAS compounds — PFOA and PFOS — to just 4 ppt in drinking water each. Roughly equivalent to a single drop in five Olympic-size swimming pools, this is the lowest concentration that current analytical instruments can reliably detect “within specific limits of precision and accuracy during routine laboratory operating conditions,” according to the EPA. Four other PFAS — PFHxS, PFNA, PFBS, and HFPO-DA, which along with a related chemical is sometimes referred to by the trade name GenX — will be regulated by combining their acceptable levels into a single value. Utilities will have three to five years to bring their systems into compliance.

Agency officials estimate that between 3,400 and 6,300 water systems will be affected by the regulation, which is the EPA’s first ever PFAS standard and the first MCL set by the agency for any chemical in drinking water in over 25 years. PFOA and PFOS account for the majority of anticipated exceedances.

GAUD is now gearing up to spend $3 to 5 million on PFAS removal technology, according to Tarbuck, much of which will be passed on to its customers in the form of higher water bills. Nationally, the price tag of meeting the standard could top $37 billion in upfront costs, in addition to $650 million in annual operating expenses, according to the American Water Works Association, or AWWA, a nonprofit lobbying group representing water utilities. That’s far higher than the EPA’s cost estimate of $777 million to $1.2 billion and a significant burden for an industry already contending with other costly priorities, such as boosting cybersecurity and “replacing all those antiquated, leaking big water pipes that transport the water from the treatment plant to the service line” that connect to homes, said Marc Edwards, a professor of civil and environmental engineering at Virginia Tech. Chris Moody, the AWWA’s regulatory technical manager, said most of the money will be spent in the next several years, as utilities race to install PFAS removal systems and other infrastructure needed to meet compliance deadlines.

In proposing the limits, EPA officials said that they had leveraged the latest science to protect the public from PFAS pollution. Environmental groups welcomed the move as long overdue. But the standard has drawn widespread criticism from the water utility industry and some scientists who say that in many places, small drops in PFAS water levels will matter little for exposure or health. “There are other strategies that get us to safer, public health protective approaches to PFAS that don’t involve the really strict standard that EPA is putting forward,” said Ned Calonge, an associate dean for public health practice at the Colorado School of Public Health and chair of a 2022 National Academies of Sciences report on PFAS exposure, testing, and clinical follow-up.

EPA officials estimate that between 3,400 and 6,300 water systems will be affected by the regulation, which is the agency’s first ever PFAS standard.

A key issue, critics say, is that the standard ensnares too many utilities with very small PFAS exceedances. Roughly 98 percent of drinking water utilities in the country, including GAUD, have maximum PFOA and PFOS levels below 10 ppt, according to the AWWA. When the levels are already so low, further reductions of a few parts per trillion “is not going to have much effect on total exposure intake,” wrote Ian Cousins, an environmental chemist at Stockholm University and one of the world’s leading researchers on PFAS exposure, in an email to Undark.

Drinking water is only one among many different pathways by which people can be exposed to PFAS. The chemicals are also in agricultural produce, fish, meat, outdoor soil, household dust, nonstick cookware, cosmetics, fast-food wrappers, stain- and water-resistant fabrics, and other products. Just how much these sources each contribute to PFAS exposure is a subject of ongoing research. But the EPA estimates that Americans get 80 percent of their PFAS intake from sources other than drinking water, and according to Cousins, dietary contributions likely account for most human exposure. The U.S. Food and Drug Administration has required the phase out of some PFAS in food packaging. But “food is contaminated via bioaccumulation in agricultural and marine food chains,” Cousins said. “We cannot clean up our food in the same way that we can add a treatment process to our drinking water.”

Yet another point of contention has to do with EPA’s methods in deriving the new limits. Scientists broadly disagree over how PFAS affect human health. Jamie DeWitt, a professor of environmental and molecular toxicology at Oregon State University who also sat on the EPA’s PFAS review panel and has appeared as an expert witness for plaintiffs in PFAS cases, emphasized that evidence from different studies links the chemicals with cancer, as well as higher cholesterol levels, elevated enzymes associated with liver damage, and reduced birth weights. Much of that evidence comes from studies of people who were highly exposed under occupational settings, or who lived near sites where the chemicals were routinely discharged into the environment.

But evidence linking the effects to trace PFAS levels is “less convincing,” said Alan Boobis, emeritus professor of toxicology at Imperial College London. Meanwhile, the EPA errs on the side of extreme caution, while health agencies elsewhere in the world apply less conservative assumptions to their own PFAS regulations. The World Health Organization, for instance, citing what it describes as “significant uncertainties and absence of consensus” over critical PFAS health endpoints, recently set a provisional guideline that limits PFOA and PFOS to a higher value of 100 ppt in drinking water and 500 ppt for all other measurable PFAS. In Australia, the drinking water PFOA guideline is 560 ppt.

Moody said neither grant programs nor settlements from litigation against PFAS manufacturers will fully cover the anticipated cost of complying with the EPA’s new standard. Some funding could be made available through recently proposed settlements with 3M and other PFAS manufacturers worth up to nearly $11.5 billion. But the pay to any one water system is limited, and utilities that opt out of the settlements might wait years to resolve their own cases.

PFAS Limits Across the Country

As of August 2023, just 24 states had instituted varying regulations for PFAS levels in drinking water. While some standards are enforceable, others are simply recommendations or only trigger notification. Shown below are the highest standard established for the two most studied compounds; PFOA and PFOS, or a combination of these, sometimes with other PFAS.

Moody’s association says that the costs of building and operating PFAS treatment systems will be borne mainly by consumers. The AWWA’s estimated rate hikes range from $305 to $3,570 per household — and could be even higher. According to Moody, the smallest communities will pay the most, since fewer households share in the total cost.

Given the “huge amount of money to comply to these guidelines,” Cousins argued that the public might be better served by a policy that prioritizes hot spots of PFAS contamination. “That would make sense from my point of view,” he said in an email. “There needs to be some pragmatism built into the regulatory process so that the limited money can be spent on the worst contamination cases first.”

FIRST CREATED in the 1930s, PFAS were later developed for commercial use during the 1940s by companies including the Minnesota Mining and Manufacturing Company, later renamed 3M. Made from a carbon backbone entwined with atoms of fluorine, the chemicals deflect water, grease, and heat and have been produced in industrial quantities for decades. PFOA and PFOS were among the first of thousands of different PFAS produced to reach the market. Used to manufacture products such as Teflon, Gore-Tex, Scotchgard fabric protectors, fire-fighting foams, and microchips, the two compounds are dubbed long-chain PFAS because their backbones contain eight carbon atoms.

Unfortunately, the same properties that make PFAS commercially useful also make them stubbornly persistent. The carbon-fluorine bond is one of the strongest in organic chemistry. PFAS resist environmental degradation and metabolism by nearly all living creatures. The most contaminated sites occur near manufacturing facilities or sites where historic PFASs were heavily used before they were phased out. For instance, groundwater sampled at wells adjacent to an industrial tannery in Rockford, Michigan, operated by a company called Wolverine World Wide, contained PFOA and PFOS at combined levels higher than 75,000 ppt. But PFAS circulate in the global atmosphere, and the chemicals have been detected as far afield as Antarctica and the Tibetan plateau, deposited there by rain and snow.

...continued in Part 2