EPA's Unprecedented Interim Drinking Water Health Advisories for PFOA and PFOS

Area of Science:

• Environmental Chemistry
• Toxicology
• Public Health

Background:

• Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants originating from commercial products and waste.
• PFAS are found in surface waters at low parts per trillion (ppt) and in groundwaters at higher concentrations (ppt or ppb).
• Recent EPA Drinking Water Health Advisories (HAs) for PFOA and PFOS have been drastically reduced.

Purpose of the Study:

• To analyze the recent changes in EPA Drinking Water Health Advisories (HAs) for specific PFAS.
• To compare the new HAs with established Minimum Reporting Levels (MRLs) and international guidelines.
• To evaluate the scientific justification for the significantly lowered HA values.

Main Methods:

• Review of current and interim EPA Drinking Water Health Advisories (HAs) for PFOA, PFOS, PFBS, and HFPO dimer acid (GenX).
• Comparison of HA values with established Minimum Reporting Levels (MRLs) for PFOA and PFOS.
• Contrast of EPA HAs with national drinking water recommendations from other countries.

Main Results:

• Interim EPA HAs for PFOA and PFOS were lowered from 70 ppt to 0.004 ppt and 0.020 ppt, respectively.
• Final HAs for PFBS and GenX chemicals were set at 2000 ppt and 10 ppt.
• Current MRLs for PFOA and PFOS are 4 ppt, exceeding the new interim HAs.
• The scientific basis for the new low EPA HAs for PFOA and PFOS is debated and differs substantially from international recommendations (often 100 ppt or higher).

Conclusions:

• The recent drastic reduction in EPA Health Advisories for PFOA and PFOS raises scientific and regulatory questions.
• The new HAs for PFOA and PFOS are unmeasurable with current MRLs.
• There is a significant discrepancy between US EPA advisories and international guidelines for PFAS in drinking water.