PFAS in Mallard Breast Tissue and Surface Water in Green Bay, Wisconsin, USA

Green Bay, Wisconsin, USA, is a popular waterfowl hunting location with thousands of waterfowl hunters visiting the area annually. Despite its popularity, the potential exposure to per- and polyfluoroalkyl substances (PFAS) through the consumption of waterfowl harvested in the area is unknown. Between 2022 and 2024, mallard duck (Anas platyrhynchos) breast tissue was collected from Green Bay and an unimpacted reference location to better understand waterfowl hunters’ exposure to PFAS. Results indicate that PFAS exposure is site-specific, as only two mallards from the reference location had detectable levels of perfluorooctane sulfonate (PFOS) in the breast tissue, while mallard breast tissue detection rates ranged from 67% to over 90% in two Green Bay locations. PFOS concentrations in the duck breast tissue were high enough to warrant a “one meal per month” (10 ng/g) and a “do not eat” (40 ng/g) advisory for mallards from Middle and Lower Green Bay, respectively, based on current consumption advisory thresholds used in Wisconsin. Paired water samples at the Lower Green Bay mallard collection site had PFOS concentrations higher than the Wisconsin surface water criteria of 8 ng/L, and the relative composition of PFAS in the water indicated multiple sources of PFAS to the area.