New data show the Dane County Regional Airport is contributing significant amounts of hazardous chemicals known as PFAS into Starkweather Creek, which empties into Lake Monona.
A report filed this week with the Department of Natural Resources showed stormwater runoff had concentrations of one compound, PFOS, at more than 55 times the limit set by Michigan, one of the few states to adopt PFAS standards for surface waters.
The DNR on Friday informed airport officials that they are responsible for discharging a hazardous substance and ordered them to investigate the extent of contamination and develop a cleanup plan.
Jason Knutson, section chief of the DNR’s wastewater division, said the agency would work with the airport to find the best way to keep PFAS out of the stream — whether by cleaning up the pollution or restricting what the airport is allowed to discharge.
The current permit expires on Dec. 31 but can be extended with current conditions if the DNR does not take action before then.
The samples were collected in April, May and June as part of the airport’s application to renew its five-year storm water permit.
The DNR requested the testing because large airports where firefighting foam is used in training — as it has been at the Madison airport — are considered likely potential sources for PFAS contamination.
It was not clear why the report was not filed until Monday, the same day the DNR released test results that showed high levels of PFAS in water from Starkweather Creek sampled downstream from the airport.
Airport spokesman Brent Kyzer-McHenry said he was not in a position to talk about the test results Friday.
PFAS are a group of chemicals found in numerous products, including foam used to fight oil-based fires. Studies have shown two of these compounds, PFOA and PFOS, may increase people’s risk of cancer and affect cholesterol levels, childhood behavior, the immune system and the ability to get pregnant.
There are no federal health standards, but the DNR is working to establish water standards for PFOA and PFOS.
The Department of Health Services has recommended a combined groundwater enforcement standard of 20 parts per trillion for those two compounds but has not issued any guidance on surface water. Michigan has set surface water standards of 11 to 12 ppt for PFOS, the compound most likely to build up in fish.
According to the report, water from four discharges had levels of PFOS between 33 and 662 ppt. Three had PFOA concentrations between 13.6 and 127 ppt.
More than a dozen other PFAS compounds were also present in the water samples.
Maria Powell, executive director of the Midwest Environmental Justice Organization, which has been raising awareness of PFAS, said the stormwater system drains an area that includes former burn pits where firefighters from multiple agencies trained with foam containing PFAS. Since 2018, MEJO has been asking government agencies to clean up the burn pits.
“They definitely should do something right away to control that discharge from going into the creek,” Powell said. “Obviously it’s a big source. ... We should turn this off and investigate this burn pit.”
Test results released Monday by the DNR showed high levels of PFAS downstream from the airport near the mouth of Starkweather Creek, which flows into Lake Monona at a popular fishing area.
The DNR is awaiting test results on fish but has not issued any health advisories against consumption.
In the wake of that report, Madison Mayor Satya Rhodes-Conway called on the Wisconsin Air National Guard to complete a comprehensive investigation and cleanup of PFAS from its activities at Truax Field, located at the airport.
The city has also said the National Guard cannot undertake $34 million in planned construction to prepare for the potential arrival of a squadron of F-35 jets without first addressing PFAS contamination.