Destroying PFAS: Less Than Meets the Eye

Model Perfluorooctanoic acid (PFOA) (C8HF15O2) molecule, one of several thousand PFAS substances

On the long list of things you need to worry about is the problem of PFAS. “PFAS” is an acronym for perfluoroalkyl or polyfluoroalkyl substances. It’s a class of chemicals composed of long chains of carbon molecules very strongly bonded with fluorine atoms, and they are damned near indestructible. Other chemicals break down by bacterial action, weathering or naturally occurring chemicals. Not PFAS.

At the same time, the stuff is ubiquitous. It’s been detected in rainfall Tibet, snow in Antartica and pretty much everywhere in between. Industrial chemistry has developed hundreds of variations, with different properties of varying utility. It’s PFAS that make your non-stick frying pan non-stick. It’s PFAS that make your carpet stain resistant. It’s PFAS that makes fire-fighting foam more effective. It’s included in many forms of woman’s makeup, food packaging, marine paints and electronics. Probably every person reading this blog post has some level of PFAS in their body tissues. Even if you are cremated, that PFAS will survive you. Because even burning PFAS at moderately high temperatures doesn’t reliably destroy the stuff.

The PFAS cycle and how PFAS moves from one location to multiple locations with the potential to impact communities. Source: Michigan Department of Environmental Quality

The problem is that PFAS is bad for you. It causes high cholesterol and high blood pressure, is linked to several kinds of cancers and can damage your immune system. It impairs cognitive development in children. The world would be a healthier place if the all PFAS products were banned, although it will take geologic epochs to get rid of the 50,000 tons a year we’ve already spread across the planet.

The good news is that scientists have found a way to more quickly breakdown PFAS: You just boil them for two hours in a solution of DMSO and lye. The bad news is that it takes two hours of boiling in highly toxic chemicals to breakdown PFAS.

DMSO – dimethyl sulfoxide – is a powerful solvent. It’s not risk free (it causes neurotoxicity at low dosages in mice) and has an explosive reaction when in contact with halogens. The fluorine in PFAS, of course, is a halogen. Lye – sodium hydroxide – is a highly caustic and powerful alkaline. It tells you a lot about the strength of PFAS chemical bonds that it takes two hours of boiling in DMSO and lye to break the PFAS down.

The bad news is that PFAS doesn’t commonly occur in high concentrations in the environment. There are chemical processes for removing PFAS from water, used in treating PFAS-contaminated drinking water, that create significant concentrations of PFAS. The process might be useful in disposing of those extracted concentrations. But otherwise, this is a nice data point, but doesn’t seem to have a lot of immediate practical applications.

Nor is it clear that the process is scalable, or what to do with the fluorine released as it is unbound from the carbon atoms.

We need to stop making the stuff, or at least sharply reduce the amounts manufactured. Eight major chemical companies entered into an agreement with the Environmental Protection Agency in 2006 called the PFOA Stewardship Program to stop production of “certain PFAS “perfluorooctanoic acid (PFOA), precursor chemicals that can break down to PFOA, and related higher homologue chemicals, and product content levels of these chemicals” in the U.S. But they can still come in through imported products. And U.S. manufacturers continue to make and use hundreds of other PFAS. The EPA says it is really close to issuing regulations limiting introduction of still more new PFASs. In the meantime, streams of new PFAS variations are being developed, manufactured and utilized.

PFASs are just one of the thousands of chemicals being released into the only biosphere we know. PFASs get the press because of their near-indestructibility. But they aren’t the worst; just the longest lived. So let’s break out the DMSO and lye and get to work.

The day after this post was written, the EPA announced it proposed to classify two PFAS substances as hazardous substances, starting the process to force cleanup of some of the most seriously contaminated sites. The proposed rule has already been criticized by the chemical industry, and it only impacts two of the hundreds of PFASs, but it’s a start.

3 thoughts on “Destroying PFAS: Less Than Meets the Eye

  1. As I understand it, we’ve essentially been poisoning ourselves, our elders, children, grandchildren, great grandchildren and great-great grandchildren then for at least decades ? And not only are we poisoning our own species but basically all other lifeforms on the planet ? And there is essentially no enforceable legislation or regulation now in place or likely to be in place in the forseeable future to prevent this poisoning from continuing on into the next century and beyond ? Yeah, I know that as a senior in my seventh decade with no progeny that I am undoubtedly not the “norm” and that I am biased by those attributes but I can honestly say that I will not be sorry to die thinking that it is likely that homo sapiens will soon(ish) come to the end of its time on planet earth. What other species has ever knowingly fouled its nest so completely ? And PFASs are only the tip of the iceberg aren’t they? (A metaphor that will soon lose all meaning as future generations will never see one.) *sigh*

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