Per- and polyfluoroalkyl substances, known as PFAS, are a diverse set of very useful chemicals — in medicine, fighting oil fires, semiconductors, and military hardware, to name a few. And because of their pervasive use, the safety assessment of PFAS is important.  Unfortunately, this assessment is far from settled internationally.

The United States Environmental Protection Agency’s (EPA) recent rule for drinking water gives a good survey of the science but then stakes out a political position of 4 parts-per-trillion (PPT) for two commonly occurring PFAS. This position is much lower than other international governments. Rather than working with these governments, EPA rushed its rulemaking to avoid what would be a very appropriate congressional review.

So how can North Carolina residents make informed decisions about PFAS contamination?  

First, consider that all of us are exposed to tens of thousands of chemicals every day. For example, coffee that many of us drink every morning is a mixture of over 1,000 chemicals.  The principal chemical is water, but 20 to 30 of these chemicals present in tiny amounts are known to cause mutations or cancer in laboratory animals at much higher levels. However, coffee as a mixture actually reduces cancer in laboratory animals, and human studies suggest this as well. 

Second, all chemicals are toxic at some level — the dose makes the poison as toxicologists are fond of saying. This applies to chemicals like Botox, the active ingredient is botulinum toxin, or otherwise the most toxic chemical known to humans (one liter of botulinum toxic could kill everyone on Earth — yikes!). At the other end of the toxicity spectrum is water — yes, people have killed themselves drinking too much of it — usually 7 liters will kill someone. And there’s no antidote. So are PFAS chemicals toxic? Yes, of course. All chemicals are toxic at some dose. 

Third, all chemicals have a safe or a virtually safe limit. This applies to botulinum toxin, which is why we can still shoot Botox into our skin. This also applies to water, where 2 liters per day are recommended. And finally, this also applies to PFAS, for just like water and Botox, the uses of PFAS must be balanced by their toxicity. But as I said before, the safety assessment of PFAS by EPA is much lower than other government authorities worldwide.

Perhaps the question North Carolina residents should ask of their government is whether we are exposed to PFAS chemicals above their safe limits. Obviously if we’re exposed to levels above these safe limits, we might expect to have some health problems, and balancing the removal of contamination with the cost of health risk would make sense. If our exposures are lower than safe limits of other government authorities, or even EPA’s much lower, political level, then we would not expect to see many if any health issues, and cleaning up such minimal contamination would be a waste of money.

So what kind of exposures are North Carolina residents experiencing? A recent study by the North Carolina DEQ showed that many samples were above EPA’s political decision of 4 PPT, indicating a potential risk, but that all samples were well below several international safe water limits, indicating little to no risk.

Our EPA folks should be talking with their international colleagues to harmonize these widely different safe limits. In the meantime, let’s all be vigilant about tracking PFAS exposures but not panic with the current exposures now being measured.