Per- and Poly-fluoroalkyl Substances (PFAS) 

Per- and polyfluoroalkyl substances or “PFAS” are a group of more than 5,000 man-made chemicals that are fire, oil, grease, water, and stain resistant and are found in a wide array of consumer and industrial products, including non-stick cookware, food packaging, dental floss, cleaning products, and cosmetics.   

The Milwaukee Metropolitan Sewerage District (MMSD) does not use PFAS in the production of Milorganite fertilizer.  Instead, wastewater reclamation facilities are passive recipients of PFAS contained in wastewater emanating from residential, commercial, and industrial products. PFAS concentrations in wastewater streams vary significantly depending on local industry and historical firefighting operations at local airports.

MMSD strongly believes that control of PFAS sources prior to entry into the wastewater stream is the solution to continued PFAS contamination. 

PFAS by the Numbers

 Products as shown in the bar graph below with typical concentrations.

PFAS infographic

National and state PFAS regulatory standards for biosolid fertilizers like Milorganite are still forthcoming. Several states have established Perfluorooctane sulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA) concentrations of less than 20 parts per billion (ppb) for biosolids like Milorganite.

Using EPA’s approved testing protocol for PFOA and PFOS, MMSD’s three most current results for these chemicals in MMSD’s Milorganite products averaged under seven ppb. 

By contrast, PFAS has been detected at the following much higher concentrations in various other products: 

  • Dust in an average home has 523 ppb  

  • Lipstick contains 216 ppb to 1,560 ppb 

  • Fast-food packaging is 7,000 to 876,000 ppb  

We recognize and share the public’s concern about PFAS and fully support more research into their impacts on public health. For more information, view the U.S. Environmental Protection Agency (EPA) website and PFAS fact sheet.