The long-lasting nature has earned PFAS the nickname “forever chemicals.” But whether that’s accurate depends on your specific question:
1. Do they last forever in the world, like there’s no way to make them go away?
No. There are demonstrated ways to destroy PFAS and turn them into not-PFAS. The most widespread of these is simply to burn them at very high temperatures (around 1,000 degrees C)1. This isn’t easy, because that’s super hot. There’s only about 20 incinerators in the US that get that hot. I feel like the clean cycle in my oven is pretty toasty and that’s about 470 degrees C. There are also other technologies that can destroy PFAS at lower temperatures or ever room temperature by adding other types of energy like chemicals, electricity, and pressure. Many of these are actively developing into full-scale technologies, and they have cool names that sound like they belong on a sci-fi TV show. Some examples include:
- supercritical water oxidation (hot and pressurized)
- hydrothermal alkaline treatment (hot, pressurized, and alkaline – i.e. the opposite of acidic or high pH)
- electrochemical oxidation (room temp, with chemicals and electricity)
- non-thermal plasma (room temp, with lots of electricity)
- advanced reduction or oxidation processes (room temp, with chemicals and fancy lamps)
2. Do they last forever in people’s bodies?
No. Like many chemicals we use, some PFAS can accumulate in people’s bodies. But they don’t stay there forever. They generally stay around for around a decade2. And they generally hang out in a.) your blood and b.) your muscles while they are checked into the you-hotel.
This doesn’t mean the just PFAS disappear from your blood – they probably go out in you pee and ultimately end up in a local river. And if your body is constantly taking in more PFAS, the level in your body might not actually change.
3. Do they last forever in the environment without human intervention?
Probably. Lots of people have studied PFAS in the environment and while many change into other PFAS, no one has observed PFSD turning into not-PFAS under natural conditions. There is some hope that bacteria will evolve a way to destroy them naturally, but it hasn’t been seen yet.
This lasting-forever-in-the-environment thing, also called “persistence,” is the most problematic thing about PFAS. It means that
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[1] Olsen, G. W., Burris, J. M., Ehresman, D. J., Froehlich, J. W., Seacat, A. M., Butenhoff, J. L., & Zobel, L. R. (2007). Half-life of serum elimination of perfluorooctanesulfonate,perfluorohexanesulfonate, and perfluorooctanoate in retired fluorochemical production workers. Environmental Health Perspectives, 115(9), 1298–1305. https://doi.org/10.1289/ehp.10009
[2] Wang, J., Lin, Z., He, X., Song, M., Westerhoff, P., Doudrick, K., & Hanigan, D. (2022). Critical Review of Thermal Decomposition of Per- and Polyfluoroalkyl Substances: Mechanisms and Implications for Thermal Treatment Processes. Environmental Science & Technology, 56(9), 5355–5370. https://doi.org/10.1021/acs.est.2c02251
PFASt and loose - an illustrated primer for normal people 