PFAS: Exposure Sources
June 8th, 2022
Whenever I talk to someone about PFAS, and they actually know what they are, I inevitably get asked questions about exposure risk. “should I avoid this?”, “I heard this has PFAS in it!”, “two towns over has it in their water.”, “NON-STICK PANS!!! NON-STICK PANS!”. So, I thought I’d write down some of my opinions and thoughts on possible PFAS exposure sources and somewhat classify them by severity.
I’ve seen estimates that put PFAS exposure of the average person at 70%-99% orally. Meaning the average person is mostly getting exposed to PFAS by eating or drinking it. Trends in blood concentrations for most PFAS have been declining since the 60s and 70s, so that’s good. In general, I usually tell people that PFAS exposure isn’t a big concern for the average person, but can be a big problem for some people.
The science around PFAS is evolving, so I plan on coming back and adding to this list as time goes on and more information is published. Most of the published PFAS research is on about 24 different PFAS. There may be as many as 3000+ individual chemicals in the PFAS group. These 24 appear to be the most common/important, but as I said, the science is evolving. I’m going to list some of the same points in multiple categories, but I explain it.
Low Risk: These are generally PFAS sources that alone don’t pose a significant exposure risk, but can be a cumulative issue.
Non-stick pans – Yeah, that’s right, when used properly (temps below 250F and without damaging the coating) modern non-stick pans don’t seem to result a significant/concerning increase in the PFAS in food cooked in them… at least not the more toxic and bioaccumulative PFAS. And yes, this is probably due to public attention on the topic.
Tap water – while some PFAS will be detectable in all water samples on earth, the concentrations found in your typical tap water aren’t something to worry too much about. If you are, the typical carbon water filter does a very good job of removing most PFAS, all though you need to actually replace it.
Food (inherent) – most non-processed foods shouldn’t have PFAS concentrations that worry you. Your apple should be okay, your flour should be okay, your beef should be okay… with some marked exceptions… which I will talk about later.
Cosmetics – while I’m not sure why some cosmetics have PFAS in them, PFAS absorption through the skin does not appear to be very strong. Don’t eat cosmetics.
Plastics – in general, plastics shouldn’t have PFAS on them. This is not the case with plastics that have been treated with a non-stick coating.
Stain resistant clothing - Wearing stain resistant clothing, in and of itself, likely isn’t an expose risk… now if a baby chews on them, or the water you wash them in, or whatever they rub on them… that could be a different story.
Medium Risk: These are PFAS sources that could get near daily intake recommendations. This is when I talk to people, I start recommending actions to avoid.
Processed food/drink and Fast food – Non-stick coatings are everywhere… especially in machinery used mass produce food. PFAS make the best non-stick coatings. Good news is that companies have become aware of this and are doing their best to rectify it.
Food packaged in disposable non-stick packaging – Why are non-stick pans not a big issue but non-stick packaging is? Well, because they aren’t made the same way and aren’t the same stuff, but mostly because of contact time and packaged food can make up a lot of peoples diets. Companies are working to remove PFAS from food packaging.
Tap water – If you live near a location that currently/historically used or manufactured PFAS, a historic firefighting training site, or near a landfill, you should probably get your tap or well water checked. The USEPA and state governments are most concerned about PFAS exposure through tap water and they are probably right. Carbon water filters, use em’.
Food (inherent) – if food is grown in soil contaminated with PFAS, watered with PFAS contaminated water, or is grown near PFAS manufacturing or use, it could have significant PFAS concentrations. Yours truly published a couple papers on this topic… even made an equation to predict it. In fact, I calculated that the soil concentrations near a few large cities could produce vegetables with concentrations that surpass tolerable daily intakes. How can soils become contaminated? Mostly application of treated municipal or industrial biosolids, but proximity to industry can contribute.
Proximity to PFAS use or manufacturing – most of this is explained in previous points. An additional factor is inhalation and atmospheric deposition of PFAS. Some PFAS production can result in PFAS entering the vapor phase where it can be inhaled or accumulate on surfaces.
Working with or producing product that use PFAS - this one is pretty self-explanatory. A lot sealants and waxes may have PFAS in them, so people who work with them can end up with reasonably high exposure.
High Risk: If you find yourself in these situations, you should be concerned. High risk PFAS exposure scenarios are typically due to a direct release of PFAS into the environment and the best way to prevent exposure to these sources is to be aware of these sites when they are discovered .
Close proximity to Firefighting training areas, airports, or military bases – Aqueous firefighting foams (AFFF) were historically made of a mixture of PFAS. In firefighting training (which often happens at airports and military bases), AFFF would end up being directly applied to soils. With repeated use, these areas often become PFAS contamination sites and can leach into nearby ground water.
Locations of PFAS manufacturing or use – When properly used and disposed of, PFAS can still result in environmental contamination. When not properly used or disposed of… significant contamination can occur.
Working with or producing product that use PFAS - To reiterate this… the highest blood PFAS concentrations I have seen have been in people who work with or make PFAS.
One last point I would like to make. There is an element of the unknown to this whole issue. As I said in the beginning, we typically analyze for 24 or so different PFAS, and there might be as many as 3000+ in the environment. Additionally, I’ve found PFAS in places and products you would not expect them in. For example, I found PFAS in some brands of methanol, which doesn’t seem that important, but it is, nearly every method used for analyzing for PFAS uses methanol in it, so if you use those brands it will contaminate your sample, and that’s really bad if you are trying to prove PFAS is not in the sample. And that’s not the only common laboratory item I’ve found PFAS in. This has resulted in me being very good at finding them due to constantly finding contamination and routing it out.
Learn more about PFAS with our other posts:
PFAS: The EPA Updates Interim Drinking Water Advisories
Our Publications on PFAS:
Plant Uptake of Per- and Polyfluoroalkyl Acids under a Maximum Bioavailability Scenario
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