The Wisconsin Department of Natural Resources has received results from surface water and sediment sampling performed in November 2019 to determine if per- and polyfluoroalkyl substances, commonly called PFAS, are present in areas that are targeted for potential cleanup-related dredging across the US EPA-designated Milwaukee Estuary Area of Concern (AOC).
Results indicate the presence of PFAS compounds in sediment and all surface water samples taken in the Milwaukee Estuary Area of Concern. PFBA (Perfluorobutanoate) was found in 100% of the surface water samples. PFBA is considered less toxic than the more widely studied compounds PFOA (Perfluorooctanoate) and PFOS (Perfluorooctane sulfonate).
Thirteen locations in the Milwaukee, Menomonee, Kinnickinnic Rivers and inner and outer harbors, as well as one location in Lake Michigan, were sampled for 35 PFAS compounds. This watershed is the most urban watershed in the state of Wisconsin with approximately 90% of the area considered urban.
The highest concentrations of PFAS were found in the samples taken furthest upstream from Lake Michigan. Among the 14 locations sampled, PFAS concentrations in sediment and surface water are highest in the Kinnickinnic River with PFHxS (Perfluorohexanesulfonate) at 44.4 parts per trillion (ppt) in surface water and PFOS at 9.1 parts per billion (ppb) in sediment.
In contrast to the Kinnickinnic River, results from sampling location 14, the location closest to the drinking water source intake for the Linnwood and Howard Avenue Water Treatment Plants, show concentrations of PFOA and PFOS at less than detection limits of 1 part per trillion (ppt) each.
Sample locations and the analytical report for the results can be found on the DNR’s website.
By comparison, the Milwaukee Estuary PFAS surface water results are generally lower than those PFAS concentrations recently found in Starkweather Creek in Madison, and higher than the recently sampled Wisconsin, Mississippi and Menomonee Rivers.
The results will inform the future management of river sediment dredged during the clean-up of the AOC. Much of the river sediment in the AOC is contaminated with “legacy contaminants,” including PCBs and PAHs, that were generated over many decades. These legacy contaminants still pose threats to environmental health – and the removal, remediation, and subsequent management of this contaminated river sediment is the focus of the AOC clean-up effort.
PFAS are a group of human-made chemicals used for decades in numerous products, including non-stick cookware, fast food wrappers, stain-resistant sprays and certain types of firefighting foam. These contaminants have made their way into the environment through spills of PFAS-containing materials and discharges of PFAS-containing wastewater to treatment plants and through use of certain types of firefighting foams. PFAS can persist in the environment and the human body for long periods of time. Recent scientific findings indicate that exposure to certain PFAS may have harmful health effects in people.
Eating fish containing elevated levels of PFAS is a potential human health concern. The Department is currently awaiting PFAS results from fish that were collected from the Milwaukee River and additional fish will be collected from the AOC in 2020. DNR’s current fish consumption guidance restricts consumption in the Milwaukee Estuary based on PCBs. People should continue to follow these advisories as we learn more. Once these fish testing results are available, the Department will work with the Wisconsin Department of Health Services to evaluate whether the advisory needs to be updated.
To keep people safe and healthy during recreational activities, DHS recommends people avoid drinking or swallowing water and to shower after swimming, wading, or playing in the water, to prevent accidental ingestion. DHS also recommends pets to be thoroughly rinsed off after contact with water. For more PFAS health-related information, please visit the DHS website.
Please visit the DNR website for more information on PFAS.