The U.S. EPA announced new nationwide drinking water standards limiting the amount of certain per- and polyfluoroalkyl substances (PFAS) in drinking water. If the proposed National Primary Drinking Water Regulation (NPDWR) is finalized, water utilities will be required to treat drinking water to remove such chemicals before it reaches households and businesses.

PFAS, which form a class of nearly 12,000 related compounds, have been referred to as "forever chemicals" because they do not break down naturally. Historically, PFAS have been used in consumer products such as food packaging, cookware, cosmetics, and certain inks, paints, and lubricants due to their nonstick, water- and oil-repellent properties. When such substances are discharged into the environment, they can accumulate almost indefinitely in soil, water, sediments, wildlife, plants and people. PFAS have been detected across the globe in places such as rain, ground and tap water, rivers, oceans and lakes, marine animals, seabirds, predators, the air, the soil, agricultural crops, and newborn babies. Certain levels of PFAS have been linked to adverse health effects in humans such as reproductive effects, increased risk of some cancers, heightened cholesterol levels, liver damage, and thyroid disease.

There are currently no national drinking water standards for PFAS, although 21 states have already proposed or adopted limits for PFAS in drinking water.

The proposed NPDWR sets stringent standards for six of the most common PFAS substances:

  • Perfluorooctanesulfonic acid (PFOS)
  • Perfluorooctanoic acid (PFOA)
  • Perfluorononanoic acid (PFNA)
  • Perfluorohexane sulfonate (PFHxS)
  • Perfluorobutane sulfonate (PFBS)
  • Hexafluoroproylene oxide dimer acid (HFPO-DA) and its ammonium salt (known together as GenX chemicals)

Levels of PFOS and PFOA in drinking water will be capped at four parts per trillion (ppt), or the equivalent of four drops in 21 million gallons of water. EPA considers this the lowest feasible quantitation level, although most water utilities are not currently equipped to detect PFAS at such low levels.

Instead of setting similar limits for PFNA, PFHxS, PFBS and the GenX chemicals, the NPDWR proposes a novel "Hazard Index" (HI) approach that would use human health reference values for such substances to calculate a ratio known as hazard quotient (HQ). Drinking water may not contain mixtures of these substances that result in an HI greater than one (1.0) when all individual HQs are summed.

Water utilities, who may be required to invest millions of dollars into new sampling, monitoring and treatment infrastructure to comply with the proposed NPDWR, have expressed significant concerns about the costs of these new regulations, which may be passed along to the public. In response, the federal government has earmarked billions of dollars in funding under the new Bipartisan Infrastructure Law for grants to state and local communities addressing PFAS in drinking water.

EPA's proposed NPDWR is the latest in an ongoing federal regulatory campaign to reduce PFAS emissions and combat PFAS contamination in the environment. A proposed rule classifying PFOA and PFOS as hazardous substances under the federal Comprehensive Environmental Response, Compensation, and Liability "Superfund" Act ( CERCLA) was published late last year and is expected to take final effect in summer 2023. Further PFAS regulation is on the horizon at the state level as well, with new legislation including PFAS reporting requirements for manufacturers and bans on the retail sale of certain PFAS-containing consumer goods proposed in more than a dozen states since January 2023.

EPA is requesting public comments on the proposed NPDWR. Interested commenters should submit comments within 60 days after the regulation is officially published in the Federal Register.

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