New tests detect no ‘forever chemicals’ in Burlington, Davenport drinking water

Tests of the treated drinking water in January in Burlington and Davenport had detectable levels of toxic chemicals that persist indefinitely in the environment, but subsequent tests in June found none, according to Iowa Department of Natural Resources data.

The question is: How?

“We did not do anything different,” said Shane Johnson, general manager for Burlington Municipal Waterworks. “Typically in the past we’ve never had a detection so we don’t know what caused it.”

The DNR has been sampling drinking water across the state for perfluoroalkyl and polyfluoroalkyl substances — commonly known as PFAS or “forever chemicals.” There are many variations of the chemicals, and they have been used for decades to make non-stick and waterproof products, firefighting foams and other items. They are under increased scrutiny for their potentially damaging health effects because research has linked them to cancers, liver damage, diminished immune systems and infant and childhood development delays.

The DNR’s tests are using more sensitive equipment than what has been utilized in past years and can detect concentrations as low as 2 parts per trillion. The U.S. Environmental Protection Agency recently lowered its health advisories — which are unenforceable safety guidelines — for two prominent PFAS from 70 parts per trillion to .004 and .02 parts per trillion.

A dozen community water supplies had detectable amounts of PFAS in their treated water when they were tested starting late last year. That means their PFAS concentrations exceeded the new health advisories. Those supplies are required by the DNR to be tested quarterly.

West Des Moines’ water had 5.3 parts per trillion of the two prominent PFAS when it was initially tested, but the utility stopped using at least one contaminated well, and in May its water had no detectable PFAS.

Burlington and the Iowa American Water Company, which supplies drinking water to Davenport, draw most of their water from the Mississippi River, and the previous tests showed the river itself was contaminated by PFAS.

There are known contaminated sites upstream on the Mississippi of 3M Company — a major manufacturer of the chemicals — but pinpointing the exact source of the river’s PFAS contamination is unclear because it drains such a large area, including parts of Illinois, Minnesota and Wisconsin.

Burlington has wells it draws drinking water from, but they account for about 15% of the city’s water supply, Johnson said. It’s not feasible right now to switch away from the Mississippi.

Iowa American Water Company, in Davenport, draws all of its raw water from the river, according to DNR data. The company has been sampling its treated water for PFAS quarterly since 2017, said Brad Nielsen, its vice president of operations. Those test results have been highly variable — some with detections, some without — and the company hasn’t been able to decipher a pattern.

“We’re still trying to learn about this and determine the best ways to address this,” he said. “American Water’s really been at the forefront of this issue.”

Keokuk also gets all of its raw water from the river and in January its treated drinking water had a combined 4.3 parts per trillion of the two prominent PFAS. The results of a more-recent test were not immediately available.

Initial tests of the Burlington and Davenport water showed those PFAS concentrations were 7.2 and 6 parts per trillion, respectively. Tests in June did not detect them.

The DNR recently started a new round of sampling of about 60 water supplies, and some early results of it are expected in the coming days or weeks, said Corey McCoid, supervisor of the DNR’s Water Supply Operations. There are no immediate plans to regularly sample the Mississippi River, he said.