What are Health Advisory Levels?

Health advisory levels were instituted in the summer of 2022 by the EPA to address common PFAS compounds and replace previous levels set in 2016. These Health Advisory levels include PFOA at 0.004 parts per trillion (ppt), PFOS at 0.02 ppt, GenX at 10 ppt, and PFBS at 2000 ppt. Health-based advisory levels are established by the EPA for chemicals in drinking water that lack maximum contaminant levels.

The EPA has set lifetime health advisory levels for PFOA (a common PFAS compound) of 4 parts per quadrillion (1,000,000,000,000,000), a level undetectable by current technology and significantly lower than the EPA’s 2016 health advisory level of 70 parts per trillion (1,000,000,000,000). To illustrate, 4 parts per quadrillion is the same ratio as 4 drops of water within the water it would take to fill 20,000 Olympic size swimming pools.

The new advisories’ exposure levels replace the previous level released in 2016 and were set near zero to provide Americans, including the most sensitive populations, with a margin of protection from a lifetime of exposure. They also consider other potential sources of exposure to these PFAS beyond drinking water, such as food, air, consumer products, etc. The EPA’s lifetime exposure calculations assumed 20% of the exposure is allocated to drinking water and the remaining 80% is attributed to all other potential exposure sources. The advisory is nonregulatory and is intended to be in place during the time between initial understanding of health effects and publication of the final enforceable National Primary Drinking Water Regulation. The EPA anticipates finalizing a maximum contaminant level for PFOA and PFOS, as well as a Health Index calculation for four other PFAS, by the end of 2023.

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1. What is PFAS?
2. What is Norfolk Doing About PFAS?
3. Is My Tap Water Safe to Drink?
4. What are Health Advisory Levels?
5. Where Can I Get More Information?