All ‘forever chemicals’ detected in Iowa drinking water exceed new safety advisories

By: - June 15, 2022 1:17 pm

The EPA's new safety thresholds for PFAS are significantly lower than its previous health advisory. (Photo by Peter Cade Stone/Getty Images)

The treated drinking water of a northeast Iowa city had nearly 3,000 times the safe amount of a toxic, man-made chemical that persists indefinitely in the environment when it was tested in February, according to new federal advisories announced Wednesday.

The Iowa Department of Natural Resources has been sampling water in dozens of cities in the past year to help determine the pervasiveness of perfluoroalkyl and polyfluoroalkyl substances — commonly known as PFAS or “forever chemicals.”

They have been used for decades to make non-stick and waterproof products, firefighting foams and other items. Recent studies have shown that they can accumulate in people’s bodies over time and can cause numerous ailments, including cancers, liver damage, diminished immune systems and infant and childhood development delays, according to the U.S. Environmental Protection Agency.

In 2009, the EPA set a safety threshold of 70 parts per trillion for the two most-prominent PFAS. On Wednesday, it lowered that health advisory of one of them to .004 parts per trillion and the other to .02 parts per trillion.

“This is a strong statement from the EPA that these are a dangerous class of chemicals,” said David Cwiertny, director of the Center for Health Effects of Environmental Contamination at the University of Iowa. “It seems to be consistent with the emerging body of science that there may not be any safe exposure.”

Current testing technology is unable to detect concentrations that small.

“Many people were very surprised that it was so low,” said Mark Moeller, supervisor of the DNR’s Water Supply Engineering Section. “When you’re talking .004 parts per trillion, that gets into the quadrillions.”

The DNR’s testing can detect concentrations as small as 1.9 parts per trillion. That means that one of the PFAS would have to be 475 times the safety threshold before it is detected.


The most-prominent chemicals, PFOA and PFOS, were detected in the treated drinking water of a dozen community supplies, including Central City, where their combined concentrations were 61 parts per trillion — the highest detected so far in the state. Test results for the other water supplies were:

Ames Water Treatment Plant: 9.6 parts per trillion
Burlington Municipal Waterworks: 7.2 parts per trillion
Camanche Water Supply: 12 parts per trillion
— Iowa-American Water Company, in Davenport: 6 parts per trillion
Kammerer Mobile Home Park, near Muscatine: 29 parts per trillion
Keokuk Municipal Water Works: 4.3 parts per trillion
Muscatine Power & Water: 7.6 parts per trillion
Rock Valley Water Supply: 2.1 parts per trillion
Sioux City Water Supply: 9.2 parts per trillion
Tama Water Supply: 5.5 parts per trillion
West Des Moines Water Works: 5.3 parts per trillion


Cedar Rapids and Iowa City treated water did not have detectable amounts, but each city had a well that did. Contaminated water from a well can be diluted in larger cities by uncontaminated water from other water sources, such as wells or rivers.

More Iowa tests planned

The DNR is poised to test about 60 more water supplies in the coming months. It has not required cities with detections to notify their residents because they were below the previous safety threshold. However, some of the cities stopped using contaminated wells, and recent tests of the drinking water in West Des Moines, for example, did not have detectable amounts of the chemicals.

Those with detections are required to test their water every three months, and the DNR might require notifications of residents based on future test results, Moeller said.

The new federal advisories are based on the health threats to people who consume the contaminated water over the course of their lifetimes. They are temporary advisories until the EPA releases its PFAS National Primary Drinking Water Regulation, which is expected later this year.

It’s unclear yet whether that will include enforceable maximum contaminant levels. The health advisories are unenforceable guidelines.

Cwiertny said the new advisories indicate federal regulators are poised to treat PFAS like other regulated cancer-causing chemicals such as benzene and tetrachloride: Have a goal of zero contamination but an enforceable level that balances the health risks with the feasibility and cost of treatment. Benzene is regulated to 5 parts per billion.

New health advisories for two other PFAS

The EPA also included first-ever health advisories on Wednesday for two other PFAS — called GenX and PFBS — that were manufactured to be safer variants of the originals. Their safety thresholds are 10 and 2,000 parts per trillion, respectively. PFBS has been detected in a number of Iowa water supplies, but typically at far lower concentrations than the new advisory, according to DNR tests.

The EPA said it is also distributing $1 billion to states to “address PFAS and other emerging contaminants in drinking water, specifically in small or disadvantaged communities.”

Moeller said there are treatment processes that cities could add to their systems, but the costs vary widely. The state also offers low-interest loans for upgrades.

The DNR initiated an investigation into the contamination in Central City because its PFAS contamination exceeded 40 parts per trillion. It’s unclear whether the DNR will adjust that threshold based on the new federal advisories.

“We’ll have to look at these changes,” Moeller said, “and think about what our next steps will be as far as investigating those sites.”


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Jared Strong
Jared Strong

Senior reporter Jared Strong has written about Iowans and the important issues that affect them for more than 15 years, previously for the Carroll Times Herald and the Des Moines Register.