EPA proposes drinking water standards for PFAS

On Tuesday the U.S. Environmental Protection Agency (EPA) announced its long awaited proposal for the national drinking water standard for six per- and polyfluoroalkyl substances (PFAS) . 

• PFOA and PFOS: EPA is proposing to regulate PFOA and PFOS at a level they can be reliably measured at 4 parts per trillion.
• PFNA, PFHxS, PFBS, and GenX Chemicals: EPA is also proposing a regulation to limit any mixture containing one or more of PFNA, PFHxS, PFBS, and/or GenX Chemicals. For these PFAS, water systems would use a hazard index calculation, defined in the proposed rule, to determine if the combined levels of these PFAS pose a potential risk.

If finalized, the proposed regulation will require public water systems to monitor for these chemicals. It will also require systems to notify the public and reduce PFAS contamination if levels exceed the proposed regulatory standards. At the announcement EPA Administrator Michael S. Regan said “EPA’s proposal to establish a national standard for PFAS in drinking water is informed by the best available science, and would help provide states with the guidance they need to make decisions that best protect their communities. This action has the potential to prevent tens of thousands of PFAS-related illnesses and marks a major step toward safeguarding all our communities from these dangerous contaminants.”

There are thousands of PFAS chemicals, and they are found in many different consumer, commercial, and industrial products. This category of chemical has been widely used for over 80 years mainly for their ability to repel oil, grease, water, and heat. We are all exposed to PFAS in everyday life. Stain-resistant carpeting, nonstick cookware, grease- and water-proof food packaging, fabric softeners, waterproof clothing, cosmetics, and through our diet and water. These forever chemicals have remained in the soil, been taken up into plants, and made their way into animals who eat those plants. According to Fairfax Water diet is responsible for 66%-72% of exposures to PFOA and PFOS (the two chemicals that have been most widely studied). In some cases, they have also leached into both surface and groundwater. Water is responsible for 22%-25% of exposures.

In anticipation of future regulations, Fairfax Water hired an independent lab to test their water using current EPA-approved methods that can detect PFAS at much lower concentrations than previous methods. Fairfax Water also participated in the Virginia Department of Health (VDH) Occurrence Study that was completed in 2021. However, the practical quantitative limit was 4 ppt just at the proposed regulatory limit.

Some of Fairfax Water’s results for PFOS and PFAS were above the MRL and the regulatory limit. The ones below cannot be quantified. PFAS dissolves in water, and combined with their chemical properties means that traditional drinking water treatment technologies used at water treatment plants are not designed to remove them, it is believed though, that carbon filtration does remove some. Activated carbon adsorption, ion exchange resins, and high-pressure membranes have been found to remove PFAS from drinking water, especially Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS), which have been the most studied of these chemicals.

Keeping PFAS out of the source water the real challenge when PFAS is in our diet and wastewater is reused in our drinking water supplies. To stay within the regulatory limit, Fairfax Water will have to identify the PFAS content in the various source of water and can mix them to minimize exposure or remove them. Source water protection will also have to be part of the solution. With that in mind both Fairfax Water and the EPA have developed an analytic framework which provides information about PFAS across the environment. This information will help them better understand potential PFAS sources in our communities and develop a road map to complying with the regulation if it is finalized and providing safe drinking water to Northern Virginia.

“At Fairfax Water, we know that drinking water is vital to public health,” stated Fairfax Water General Manager Jamie Hedges.  “We’ve taken a proactive approach to address PFAS through voluntary PFAS monitoring and educating the community on the importance of protecting the region’s source water from these compounds.  Stopping PFAS at the source, before it reaches drinking water sources, is key to ensuring our customers have high-quality water at affordable rates.”