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
- 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.