Foam with ‘forever chemicals’ found in two Twin Cities streams
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State researchers have found foam containing elevated levels of PFAS, sometimes known as “forever chemicals,” in two streams in the east Twin Cities metro area.
Officials from the Minnesota Pollution Control Agency and the Minnesota Department of Health said that there's no immediate health threat to the public. But they are cautioning people to keep away from the foam and take precautions if they — or their pets — come into contact with it.
The foam was found in Raleigh Creek in Washington County and Battle Creek in Ramsey County. Researchers made the discoveries while testing surface waters last year.
PFAS — short for per- and polyfluoroalkyl substances — are a broad class of man-made chemicals known for their durability and ability to repel water and grease. Their tendency not to break down made them useful for consumer products ranging from Teflon pans to Scotchgard fabric protectors.
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Maplewood-based 3M produced two PFAS compounds in the eastern Twin Cities for decades, beginning in the 1950s. Waste containing PFAS chemicals was legally disposed of in landfills in the eastern metro area, where the chemicals leached into the groundwater, and contaminated the drinking water supplies of several communities.
The state of Minnesota sued 3M over its role in the contamination. In 2018, 3M agreed to pay $850 million to provide clean drinking water to the affected communities and clean up natural resources.
At a news briefing on Monday in St. Paul, MPCA assistant commissioner Kirk Koudelka said four instances of PFAS foam were found along Raleigh Creek in Oakdale and in the city of Lake Elmo. The stream was already known to contain PFAS, but the foam the MPCA found has a higher concentration of the chemicals than the stream itself, he said.
PFAS tend to hang out at the top of the water, “kind of like a skin on top of pudding,” Koudelka said.
“When it starts to get abrasions or friction because of wind or going over rocks, small rapids … is when we get foam that occurs,” he said.
Foam contaminated with looks the same as any other foam that occurs naturally in a stream, making it impossible to distinguish between the two, Koudelka said. It can be bright white or a darker color. While PFAS foam hasn’t been commonly found in Minnesota, the phenomenon is seen frequently in other states such as Michigan.
MPCA officials believe the PFAS contamination in Raleigh Creek originated at nearby sites where 3M disposed of waste containing the chemicals in the past. They also think that a large flood control project built in the late 1980s likely played a role.
Known as Project 1007, the mitigation project was built to protect homes in Oakdale’s the Tri-Lakes area by using stormwater pipes and channels to move water away from them and toward the St. Croix River. But it also appears that project also helped transport PFAS, Koudelka said.
The Ramsey County site where foam was found — Battle Creek — is more of a mystery. Officials said the area is not part of the 3M investigation.
Researchers were collecting samples in the area because of a Minnesota Department of Transportation project nearby. They found foam containing PFAS in Battle Creek, the water body that gives the nearby St. Paul neighborhood and regional park their names — and collected a handful of water samples from Battle Creek and Battle Creek Lake with low concentrations of PFAS.
Long-term exposure of primary concern
Agency officials said the foam itself doesn't pose a direct threat to human health. The major concern with PFAS is long-term exposure in drinking water, said Jim Kelly, manager of the environmental health division at the Minnesota Department of Health.
“Our focus in the east metro through all these years has really been on drinking water and preventing people from ingesting water containing these chemicals,” he said. “So what we're what we're recommending then is people simply just avoid that.”
Kelly said out of an abundance of caution, they’re advising people to avoid contact with foam in the streams. If they do come touch it, or if their pet does, they should wash the skin or fur with soap and water.
The MPCA has notified people who live along Raleigh Creek about the findings, and is cautioning them to keep away from the foam. The other stream, Battle Creek, runs through a park, so there aren’t homes close by, officials said.
Both the MPCA and the health department plan to do more testing of both the groundwater and the surface water at both locations, in hopes of better understanding how the two are connected. MPCA staff are collecting additional samples and Battle Creek and Battle Lake and hope to have the results by next month, Koudelka said.
The MPCA also sent a letter to 3M this week saying it thinks the site where the company disposed of PFAS in Oakdale could be continuing to release the chemicals into the surface water, and directing the company to determine how to address it. 3M has not yet responded, Koudelka said.
