Recent US State and Federal Drinking Water Guidelines for Per- and Polyfluoroalkyl Substances

Area of Science:

• Environmental toxicology
• Environmental chemistry
• Public health

Background:

• Per- and polyfluoroalkyl substances (PFAS) are persistent, bioaccumulative synthetic chemicals with documented health effects.
• The U.S. Environmental Protection Agency (USEPA) set non-enforceable drinking water advisories for PFOA and PFOS in 2016.
• Growing concerns over PFAS health impacts have led some U.S. states to establish more stringent guidelines than federal advisories.

Purpose of the Study:

• To critically review the scientific basis for U.S. state and federal drinking water guidelines for PFOA and PFOS.
• To analyze the factors contributing to variations among state-level PFAS guidelines.
• To provide context for the development of future PFAS regulations.

Main Methods:

• Literature review and synthesis of scientific data.
• Comparative analysis of existing state and federal drinking water guidelines for PFAS.
• Examination of toxicity and exposure data informing guideline development.

Main Results:

• State guidelines for PFOA and PFOS are generally more protective than the 2016 USEPA advisories, with a 4-fold range observed among states.
• Guidelines differ based on toxicity and exposure considerations, reflecting scientific interpretation and evolving data.
• Several states have also established guidelines for other PFAS beyond PFOA and PFOS.

Conclusions:

• State-level PFAS drinking water guidelines are evolving towards greater protection, driven by scientific evidence.
• Variability in state guidelines is expected due to differing scientific assessments and timelines.
• Continued development of state-specific PFAS guidelines is anticipated, necessitating ongoing scientific evaluation.