‘Forever chemicals’ detected in tap water
Low levels of PFAS persist even after treatment
Milwaukee’s drinking water system contains low levels of several perfluorinated chemicals — a suite of compounds under growing scrutiny in Wisconsin, and nationally, because of the potential harm they pose to humans.
Sampling conducted in 2017 and 2018 showed the chemicals turned up for the first time in both raw water and after it was treated by Milwaukee Water Works, which serves about 865,000 people in Milwaukee and 16 other communities.
The findings have prompted the state’s largest water utility to consider investing in costly new treatment technology to remove the contaminants in a system that pumps about 100 million gallons of treated water a day.
The results are well below strict new enforcement standards proposed in June by the administration of Democratic Gov. Tony Evers.
But their presence at detectable levels underscores the widespread nature of “forever chemicals” — so-named for their difficulty to dissolve or break down, even in water bodies as large as Lake Michigan.
Epidemiology studies have suggested that the chemicals — known generically as PFAS — can lead to an increased risk of pregnancy-induced hypertension, liver damage, thyroid disease, asthma, decreased fertility, some cancers and a decline in response to vaccines.
The compounds have been used for decades in industry and consumer products, ranging from fire retardants to nonstick pans.
In Wisconsin, much of the focus on these emerging contaminants has been their ability to seep through soil and contaminate groundwater.
Most notable: Well contamination in Marinette, in the northeast corner of the state, where Johnson Controls International of Glendale disclosed recently it was setting aside $140 million to clean up PFAS-laden firefighting foams manufactured by a subsidiary.
In Madison, the city has taken one well out of operation on the city’s east side where PFAS compounds have been detected near the Air National Guard’s Truax Field.
In Milwaukee’s case, chemicals have been detected at low levels in raw water from Lake Michigan; and in some cases, at slightly higher levels after treatment.
Karen Dettmer, superintendent of Milwaukee’s water system, said the findings are a concern but not a cause for alarm because concentrations are at low levels and often barely detectable.
However, the results have prompted the water utility to evaluate a switch to a different filter technology — granular activated carbon — especially if additional compounds are added to the state’s proposed standard, Dettmer said.
Installing the carbon technology would represent a “significant investment,” and could mean higher rates for customers, Dettmer said. “It’s not something that we are going to move on in the next five or six years, but it’s on my mind,” she said.
Milwaukee now uses 2 feet of anthracite coal and 1 foot of sand to remove tiny particles in one stage of water treatment to screen out unwanted material.
The Evers administration proposal calls for a combined limit of 20 parts per trillion in groundwater for two widely used compounds — PFOS and PFOA. The standard represents a lifetime exposure.
Milwaukee’s water comes from the lake, but Steve Elmore, the state Department of Natural Resources’ director of drinking water and groundwater, said the two are comparable because in both cases people could be consuming the water.
The regulations are not yet law and have come under criticism from business groups, including Wisconsin Manufacturers & Commerce and the Wisconsin Paper Council. They say the chemicals’ ability to harm humans has not been established and costs to remove the contaminants are prohibitive.
The U.S. Environmental Protection Agency has established a health advisory in drinking water of 70 parts per trillion for a combined concentration of the two compounds. But the federal guidance is not legally enforceable, prompting many states to begin setting their own standards for safety.
In 2018, the cumulative results in Milwaukee for PFOS and PFOA ranged from about 4 to 6 parts per trillion. In 2017, it was about 4 parts per trillion, according to city records.
Elmore said detections below 20 are “not a big concern but possibly something to watch.”
In Madison, officials removed an east side well from use in March that had a combined measure of 12 parts per trillion. But spokeswoman Amy Barrilleaux said the reason for taking it offline was due to the presence of another perfluorinated compound, PFHxS, with readings showing about 20 parts per trillion.
PFHxS is not a chemical that state agencies are currently recommending for the new standard, but Barrilleaux said the city is taking the precaution “because this is an evolving science.”
Dettmer told a legislative hearing on Aug. 13 at the University of WisconsinMilwaukee that the city began sampling water in 2013 “as an overabundance of caution,” and is now testing for 45 different PFAS compounds.
Detection technology has improved, and by 2017, Dettmer said samples began to show results that were measurable.
“As a surface water utility, we see much less risk as some of the groundwater utilities have experienced,” Dettmer told a bipartisan task force on water quality holding hearings around the state.
The task force was created by Assembly Speaker Robin Vos (R-Rochester.)
“But that doesn’t mean that we are going to be any less diligent in ensuring that we are aware of what’s getting into our water,” Dettmer said.