The Washington Department of Ecology (Ecology) in September released an Assessment of PFAS Levels in Washington State Biosolids, documenting the results of a study begun in 2024 to assess PFAS concentrations in biosolids generated by 44 wastewater treatment plants across the state. Ecology explored facilities of various sizes and locations, and explored the results of sampling under U.S. EPA Method 1633. The state acknowledges that although the study was limited in scope, the 2025 passage of Senate Bill 5033 concerning sampling or testing of biosolids for PFAS chemicals will help the department gather additional data on frequency and location to inform policy decisions.
For more information on the state’s PFAS efforts, see here.
