Duck on the Menominee River | Laina G. Stebbins

State agencies are warning Wisconsinites to limit the amount of ducks that they eat, or to avoid certain birds entirely, due to PFAS contamination. Waterfowl harvested around Green Bay were shown to have high levels of the man-made “forever chemicals,” which persist in the environment forever and have been linked to several chronic diseases including cancers. 

The Department of Natural Resources (DNR) and Department of Health Services (DHS) are advising people not to eat mallards from around lower Green Bay from Longtail Point to Point au Sable, and south of the mouth of the Fox River. Additionally, mallards and wood ducks living around Green Bay from the city of Marinette across to Sturgeon Bay should not be consumed frequently — no more more often than once per month for mallards and only one meal per week for wood ducks. 

Back in 2022 levels of polychlorinated biphenyls (PCBs), another man-made chemical, in waterfowl led to similar advisories in lower Green Bay. Further assessments found concentrations of PFAS in breast muscle tissue, according to a DNR press release. In 2023 and 2024, more samples were taken from ducks, with all samples taken during July and August when the birds were most likely to represent local breeding populations. Those efforts revealed elevated levels of perfluorooctane sulfonate (PFOS), which is a type of PFAS, in the breast muscles of the birds. The inquiry suggested that both adult and juvenile ducks in lower Green Bay have higher concentrations of PFOS than in the northern portion of the bay. 

PFAS chemicals were first developed as part of U.S. government nuclear and atomic weapons research during the Manhattan Project. After the project ended private companies, particularly DuPont, began researching the compounds for commercial use. Over the subsequent decades, PFAS was used in products including  non-stick Teflon pans, fast food wrappers, and firefighting foam. The chemicals do not degrade in the environment, nor within the body, and have been linked to cancers and other chronic diseases. 

The DNR tracks PFAS consumption advisories spanning multiple species including deer, fish and waterfowl. On Sept. 4, deer and fish advisories for PFAS were issued for the Town of Stella and surrounding waterbodies in Oneida County. All fish in the Moen Lake Chain were included in a “do not eat” advisory due to PFAS contamination, and a similar warning was distributed against the consumption of deer liver near the Town of Stella.