EPA Releases Very Low Drinking Water PFAS Health Advisory Levels

Insight

EPA Announces Dramatically Lower PFAS Health Advisory Levels for Drinking Water

With some HALs over 1000x lower than previous levels, and well below the detection levels of current analytical methods, the need to separate, concentrate and destroy PFAS will intensify across the United States.

The U.S. Environmental Protection Agency (EPA) has made significant regulatory changes in its treatment of PFAS. These include updates to regional screening levels (RSLs) and health advisory levels (HALs) that inform local decisions regarding PFAS treatment and remediation. The new levels are designed to help communities prepare for a seismic shift in PFAS policy—a National Drinking Water Regulation—set to be proposed later this year.

Until EPA’s announcement on June 15, the HAL for two PFAS compounds, PFOS and PFOA, had been set at 70 ppt (for the two chemicals individually or combined). At the state level, guidance values have been dropping dramatically since 2016. Now, the EPA’s revised HALs for some PFAS compounds are below detection levels and 1000x lower than previous guidance.

The American Water Works Association said in a statement, “At the low levels set in the health advisories, protecting source water from PFAS contamination is critical. AWWA urges Congress and other decision-makers to implement policies that keep harmful PFAS out of our communities, especially the nation’s drinking water supply.”

Sharply Lower Health Advisory Levels

The EPA released new HALs for PFBS and Gen-X and revised HALs for PFOS and PFOA on June 15, 2022:

PFOA: 0. 004 ppt
PFOS: 0.02 ppt
GenX: 10 ppt
PFBS: 2,000 ppt

EPA relies on health advisories to warn the nation about contaminants that can cause human health effects and are known or anticipated to occur in drinking water. According to EPA’s news release, the new HALs will stay in place until the agency establishes a National Primary Drinking Water Regulation for these chemicals.

The move was inspired by new toxicological data. In particular, EPA draft reference doses (RfDs) protective of non-cancer health endpoints for PFOS and PFOA were lowered by approximately four orders of magnitude to be protective of immunotoxicity.

"By setting HALs below the detection limits of current analytical methods, EPA is declaring that there is potential health risk of any detection of these chemicals in drinking water; likely affecting hundreds, if not thousands, of drinking water systems nationwide. In addition, the PFOA HAL of 0.004 ppt implies that 2.2 gallons of PFOA are capable of contaminating one quadrillion gallons of water, or roughly the volume of Lake Michigan. This means that even small and non-point sources of PFAS could potentially threaten drinking water supplies,” said CDM Smith vice president and remediation practice leader Tamzen Macbeth.

The HALs for PFOS and PFOA are derived using the same methodology as the maximum contaminant level goals (MCLGs). MCLGs represent the level of a contaminant in drinking water below which there is no known or expected risk to health and are the starting point for the development of maximum contaminant levels (MCLs). MCLs are set as close to the MCLG as possible, using the best available treatment technology and taking cost into consideration. MCLs are enforceable standards, and their release will represent one of the most significant developments since the agency embarked upon its PFAS Roadmap.

EPA is declaring that there is potential health risk of any detection of these chemicals in drinking water; likely affecting hundreds, if not thousands, of drinking water systems nationwide.

Tamzen Macbeth, Remediation Practice Leader

Expanded Screening Levels

EPA has added five additional PFAS to its list of RSLs, bringing the total to six analytes: PFOS, PFOA, PFBS, Gen-X, PFNA, and PFHxS. The agency adopted toxicological reference values from the EPA Office of Water for Gen-X, and the Agency for Toxic Substances and Disease Registry for the other four analytes.

The agency combines exposure assumptions with chemical-specific toxicity values to create its RSL tables, which are recommended for use in risk assessments at CERCLA sites. Rather than serving as cleanup standards, RSLs help EPA identify the need for more sampling, further risk assessment and potential response actions for impacted environmental media.

What’s Next: Separate, Concentrate, Destroy

Treatment options for PFAS will remain vital for water providers seeking to ensure safe drinking water supplies. In addition to the most common treatment options, granular activated carbon (GAC) and anion exchange (AIX), reverse osmosis is likely to find greater relevance for utilities that need to remove PFAS to nondetect levels. As pioneers in the treatment of PFAS and the designers of the first surface water treatment facility in the country to use low pressure reverse osmosis (LPRO) for post- filtration advanced treatment to remove PFAS, CDM Smith is committed to helping our clients navigate this regulatory environment.

PFAS destruction technologies will also be crucial to tackling this environmental crisis. CDM Smith has been investigating PFAS destruction for nearly a decade. However, only the most aggressive and energy-intensive technologies are capable of breaking down PFAS. Therefore, cost-efficient treatment options for large volumes of contaminated water rely on coupling technologies that first separate and concentrate PFAS to reduce the volumes and make destructive treatment technologies viable. As our work in this realm continues, we’ll share with you the latest news via our Breaking Down PFAS newsletter.

According to the agency’s latest news release, EPA is still on track to deliver the first proposed PFAS National Drinking Water Regulation this fall.

Assessing and communicating PFAS risk

Heather Lanza, a researcher and expert in PFAS risk, shares her findings on key toxicological research, COVID-19 vaccine response, and how utilities can successfully communicate risk to their consumers.