June 22, 2022 – On June 15, the Environmental Protection Agency (EPA) released updated health advisories warning that even tiny amounts of two types of man-made compounds, PFOS and PFOA, are harmful to humans. Currently these compounds are found in drinking water systems across the U.S. Philippe Grandjean, adjunct professor of environmental health at Harvard T.H. Chan School of Public Health, discusses the new guidelines.
Q: Can you describe the EPA’s new advisories and their implications?
A: The EPA issued guidelines with new limits for how much PFOS and PFOA should be in drinking water. Both of these compounds are part of a larger class of chemicals called PFASs—per- and poly-fluoroalkyl substances—which are also known as “forever chemicals” because they don’t break down in the environment over time. These chemicals have water- and grease-resistant properties and are used in a wide variety of products, including nonstick cookware, waterproof clothing, food packaging, and firefighting foams. PFAS exposure has been linked with health issues such as kidney and testicular cancer, weakened immunity, endocrine disruption, fertility problems, and decreased birth weight.
The previous guideline, set in 2016, set a limit of 70 parts per trillion (ppt) for both PFOS and PFOA in drinking water. The new advisories decrease that by more than a thousandfold. The new limit for PFOS is 0.02 ppt; for PFOA, it’s 0.004 ppt. Essentially, the EPA wants the limits to be as close as possible to zero as a growing body of research has shown how toxic these compounds are.
These new advisories are exactly in line with findings from some of our previous studies, which showed some of the serious health problems associated with PFAS exposure. For example, our 2012 study showed that children with higher PFAS exposure had a poorer response to routine childhood vaccinations against diphtheria and tetanus. We found that when PFAS exposure was doubled, children would lose 50% of the antibodies they should have had from their vaccinations—meaning that more and more of them were not being sufficiently protected against those diseases.
Our research has also shown that children with higher levels of PFAS when they were born—we measured the levels in cord blood—had lower antibody levels in response to later vaccinations. In addition, PFAS is transmitted through human milk. Unfortunately, the baby can end up with up to 10 times more PFAS in their blood than the mother had.
The EPA decided that since children are being born with PFAS in their bodies and they’re getting it from human milk, they needed to figure out how to limit exposure in the general population to protect pregnant women. This was really inventive. It is the first time that I know of that a U.S. regulatory agency decided to protect the child by setting an exposure limit that takes into account a mother’s exposure.
Q: A recent USA Today article noted that the new advisories “stunned” scientists and officials across the country. Why were people so surprised by the EPA’s move?
A: What is surprising is that the decrease is very, very big. We’re talking about PFAS concentrations in the water that are very hard, if not impossible, to measure with our current methodologies and instrumentation. I think it’s entirely possible that we can measure these concentrations accurately, but it’s going to take time to develop new methods.
The EPA’s new advisories also create some uncertainty and confusion. The EPA is saying that it’s important to get the PFAS contamination of drinking water as close to zero as possible. I agree. But the problem is that there’s no way right now to get drinking water in agreement with the new limit. At least 100 million Americans are drinking water that probably has PFAS levels exceeding the current limit of 70 ppt. Because the guidelines are not legally binding, it’s hard to know what difference they are going to make. If a community wants to sue a particular source of PFAS contamination, can they rely on EPA’s guidelines at all? Would they hold any weight in inspiring better prevention at state and community levels?
Furthermore, a number of individual states, including Massachusetts, New Hampshire, Vermont, Michigan, New Jersey, and California, have lowered their guidelines on how much PFAS can be in drinking water, and in some cases those limits are legally binding. They’re lower than 70 ppt but much higher than the very low limits the EPA just announced. The EPA guidelines could be a goal, but it would be more helpful to have a binding intermediate limit for PFAS that we would have to respect in the short term.
Q: The EPA also issued final health advisories for compounds known as GenX and PFBS, which are considered replacements for PFOA and PFOS, respectively. What can you tell us about those?
A: The limits on these two substances are higher than those for PFOS and PFOA because there are no human studies yet showing their harms. Almost undoubtedly the guidelines issued by the EPA for these substances are way too high.
There are probably thousands of compounds that are similar to these four, and they are unregulated. What’s happening is that industry—for example, for the fire-extinguishing foam known as AAAF—just uses some other PFAS instead of PFOA or PFOS. It’s what is called regrettable substitution—when you ban one kind of chemical and then you get something that may be just as bad or worse.
Some of the EU member states are working with the European Commission to figure out a way that member states can essentially regulate all of these PFAS. So there is a political movement to generate some sort of legislation that can protect Europeans from PFAS alternatives.
Many colleagues have expressed their frustration that we in the U.S., as well as internationally, are still discussing how to control the “old” PFASs, while we haven’t had time to document the new substitutes. That may take decades. Should we in the meantime allow the new PFASs to enter the environment and ourselves while waiting for the scientific evidence to develop? I would as a physician emphasize the need for prudent prevention and a strategy that protects us against the whole family of PFASs.