New test results show water draining from the Madison airport contains harmful PFAS compounds at thousands of times the concentrations considered safe by other states.
Various fluorinated compounds, which have been linked to cancer and other health problems, were found in water taken from 23 outfalls, which drain into Starkweather Creek, according to a report provided Wednesday to the State Journal.
Water from 12 of the outfalls had levels of one such compound, PFOS, which tends to accumulate in fish, that exceeded the 12 parts per trillion limit set by Michigan, one of the few states to adopt PFAS standards for surface water.
One site had a PFOS concentration of 17,500 parts per trillion; another had a concentration of 2,220 ppt.
The report shows the chemicals at much higher concentrations and in areas that were not identified in tests conducted last year. The report notes that two of the areas with some of the highest contamination drain areas of the Wisconsin Air National Guard base, which has previously been identified as a source of PFAS.
Maria Powell, executive director of the Midwest Environmental Justice Organization and leading advocate for PFAS regulation, called the results “astounding.”
“We hope Dane County will be identifying all of these PFAS sources and taking steps to remediate them as soon as possible,” Powell said.
The county plans to begin a pilot study this month using booms and a technology known as bioavailable absorbent media — or “BAM” — to treat water at the outfall with the highest concentration, according to the report.
According to the manufacturer, Orin Technologies, the treatment uses a honeycomb-type substance made mostly of carbon and derived from “a proprietary blend of organic materials” to soak up and eliminate biodegradable compounds.
Powell called the measures outlined in the report “good first steps” but said unless the county and Air National Guard also investigate and clean up the full extent of soil and groundwater contamination throughout the airport and military base — as required by state environmental law — “PFAS will continue to seep into Starkweather Creek.”
The county announced the findings in a news release that did not include specific test results. According to the release, both the cleanup and investigation have been interrupted by the COVID-19 health crisis, which also forced the cancellation of a public information meeting.
The county says it plans to hold an online meeting instead but has not provided a date.
In October, the state Department of Natural Resources notified county officials they are responsible for discharging hazardous substances and ordered them to launch an investigation and cleanup plan after test results showed high levels of PFAS in water draining into Starkweather Creek.
Test results of samples collected last spring as part of a stormwater permit renewal process showed PFOS concentrations of up to 662 ppt.
Subsequent tests have revealed high levels of PFAS in the creek, which empties into Lake Monona.
In January state health officials warned against eating certain fish from Lake Monona after the chemicals were found in them.
Last month the county agreed to pay more than $6,000 in legal bills as part of a settlement with a group of environmental advocates who sued to get records of county leaders’ communications about PFAS.
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. PFAS chemicals don’t naturally break down and there is no known way to destroy them.
There are no federal health standards, but the DNR is working to establish water standards for PFOA and PFOS. In a March presentation to a PFAS stakeholder group, the DNR said it is considering a likely limit of 2 ppt for PFOS.