Per- and Polyfluoroalkyl Substances (PFAS)

Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that includes Perfluorooctanoic acid(PFOA), Perfluorooctane sulfonic acid (PFOS), Hexafluoropropylene oxide dimer acid (GenX), Perfluorobutane sulfonic acid (PFBS), and many other chemicals. PFAS have been manufactured and used in a variety of industries around the globe, including in the United States since the 1940s.  There is evidence that exposure to PFAS can lead to adverse human health effects.

PFAS can be found in:

  • Food packaged in PFAS-containing materials, processed with equipment that used PFAS, or grown in PFAS-contaminated soil or water.
  • Commercial household products, including stain- and water-repellent fabrics, nonstick products (e.g., Teflon), polishes, waxes, paints, cleaning products, and fire-fighting foams (a major source of groundwater contamination at airports and military bases where firefighting training occurs).
  • Workplace, including production facilities or industries (e.g., chrome plating, electronics manufacturing or oil recovery) that use PFAS.
  • Drinking water, typically localized and associated with a specific facility (e.g., manufacturer, landfill, wastewater treatment plant, firefighter training facility).
  • Living organisms, including fish, animals and humans, where PFAS have the ability to build up and persist over time.

Proposed National Primary Drinking Water Regulation

On March 14, 2023, EPA released the pre-publication of the proposed National Primary Drinking Water Regulation (NPDWR) for PFOA and PFOS, along with four additional PFAS. EPA is proposing to set a Maximum Contaminant Level (MCL) for PFOA and PFOS (see table below) and is proposing to address four additional PFAS (GenX, PFBS, PFNA, and PFHxS) as a mixture using a Hazard Index. The Hazard Index is a tool typically used to evaluate potential health risks from exposure to chemical mixtures.  However, this is the first time a Hazard Index is used for a drinking water standard. See table below for the proposed Maximum Contaminant Level Goals (MCLGs) for each of the six PFAS. 

PFAS Compound Proposed MCLG Proposed MCL Standard Health Effects for public notice
Perfluorooctanoic acid(PFOA) 0 ppt 4.0 ppt Some people, including children, who drink water containing PFOS/PFOA in excess of the MCL could develop immune health effects, fetal growth effects after exposure during pregnancy, certain types of cancers, or an increased risk of cardiovascular disease or liver disease.
Perfluorooctane sulfonic acid (PFOS)
Perfluorononanoic acid (PFNA) 1.0 (unitless Hazard Index) 1.0 (unitless Hazard Index) Some people who drink water containing PFHxS, HFPO-DA, PFNA, and PFBS in excess of the Hazard Index MCL could develop thyroid, liver, or developmental health effects.
Perfluorohexanesulfonic acid (PFHxS)
Perfluorobutanesulfonic acid (PFBS)
Hexafluoropropylene oxide dimer acid (HFPO-DA/GenX)

Health Advisories

On June 15, 2022, the U.S. Environmental Protection Agency (EPA) released health advisory recommendations for four per-and polyfluoroalkyl substances (PFAS) which are noted below: 

PFAS Health Advisories (Parts per trillion (ppt))
Perfluorooctanoic acid(PFOA) 0.004 (Interim)
Perfluorooctane sulfonic acid (PFOS) 0.02  (Interim)
Hexafluoropropylene oxide dimer acid (GenX) 10 (Final)
Perfluorobutane sulfonic acid (PFBS) 2,000 (Final)

Health advisories for contaminants in drinking water are not regulatory values and are not enforceable.  Health advisories are based on non-cancer health effects, and are for different lengths of exposure (one day, ten days, or lifetime).  The health advisories noted above are for a lifetime exposure.  Furthermore, two of the health advisories are interim and subject to change after scientific reviews are finalized.


Helpful Links

The U.S. Environmental Protection Agency

Q and A on EPA PFAS Drinking Water Health Advisories

Louisiana Drinking Water Watch - The drinking water watch allows consumers to review chemical and bacteriological data pertaining to their water system.