Undead Chemicals

The thing you have to understand about PFAS, or forever chemicals, is that they go against nature. 

I don’t mean this morally, although the case can be made. I mean it functionally. Normally, the butter that keeps your eggs from sticking to a cast-iron pan burns off. Pizza boxes and paper plates soaked with grease fall apart; rainwater eventually soaks a jacket. The pulp that becomes toilet paper and paper towels clumps, and sticks, to the machinery that extrudes them. The grease that lubricates a drill bit cutting through oily shales eventually grinds away. 

But take your common oily hydrocarbon and zap it with fluorine gas — turning reactive hydrogen into rock-solid fluorine — and you end up with something very different: a man-made synthetic oil that is almost impossible to break down. 

You have Gore-Tex where once there was sticky oilcloth. Teflon instead of grease stains in a pan. Clean strips of Scotch tape instead of messy wax paper and glue.All bordering on miraculous. Or, to put it another way: uncanny. Eternal. 

Undead.

This is Heat Death, the newsletter that, no matter what, will always react with oxygen. Our guest today is Dr. Andrea Gore, who runs a lab at the University of Texas at Austin that specializes on the impact on the body of endocrine-disrupting chemicals.

These are substances  like plastics, pesticides and PFAS — mostly derived from fossil fuels — which hijack our own bodies’ most intimate systems. Building up, deathless, in our flesh and that of everything around us. 

In 2024, Gore told me for a Hill article that for PFAS, as for thousands of chemical varieties, there might be no truly safe level. Today, she walks us through this strange class of chemicals, and what they do to life.

It's Heat Death. Stay with us.

Saul Elbein: It seems like if you want something that has the properties of a normal lipid — but is much, much more stable, or which causes things to behave in ways really contrary to the way they want to behave when they react with oil or water, PFAS is your friend. Is that a fair way to describe it?

DR. ANDREA GORE: I think that's a good way to explain it. Part of it is that some chemicals, like PFAS,have very, very strong bonds between the molecules that make these chemicals up. They're very difficult to break down.

They're like lipids, so they dissolve very well in oils, and they're also really hard to get rid of. It's like washing the dishes where you have a lot of oil — it doesn't dissolve in water, right? It's not like you're pouring detergent into the groundwater to break it down, and detergent wouldn't break PFAS down anyway, because of the power of those chemical bonds. You probably need to add other kinds of chemicals to break them down. So the bottom line is, they're just really persistent.

Would it form like a slick in the groundwater? Is it sort of like an emulsion?

It would be more like an emulsion. I mean, when there's fatty substances that are in water, they're not dissolved in water, they're kind of floating around in water. They can contact each other and kind of glob up.

Okay, so like you have your sort of natural lipids, or in case of wastewater, you have your congealed lipids that came from being put down people's drains. PFAS is going to easily dissolve into that.

The bigger problem is they're in the water, and that water can be used for irrigation or for ranch animals, and in some cases, depending upon water purification systems, even get into the water that we're drinking. They also get taken up by plants. They get into the food chain. So I think we also are getting exposed through the food chain as well as through the water. 

My understanding is that the systems PFAS are disrupting are pretty fundamental to most life on Earth, going back several billion years. So what does it do to complex life in broad strokes?

Maybe they get in our drinking water. Maybe they don't, but if we get it through ingestion, then it's like eating a fatty meal, right? Some of the fats are going to get absorbed into our body, and wemay use it for energy, or store it. That's why we have fat: Fat is the body's major food storage component, so it makes sure that we're not going to starve to death. It's a protective mechanism that evolved when animals first evolved and started having fat to be able to have these stores.

PFAS, because it's similar in structure to fatty molecules, can also get into our fat, so it gets deposited and stored in our body. And some of it can ooze out. We're constantly breaking down and building our fat stores. If we're fasting, our body will initially break down all our sugar, but once you've burned through your sugar, and you don't have that much sugar storage in your body, you start burning fats. When you start burning fat, what you're doing is you're breaking down your food stores.

If PFAS can build up in our food stores, our body has no natural way of breaking it down. We have enzymes that are designed to break down natural animal and plant fats, not enzymes designed to break down the different PFAS components. It can get into your blood system when breaking down our food stores,so we now have these chemicals in our body. They can get into different organ systems, and that's when they start having health and biological effects.

You're a neuroscientist. Why is the brain particularly vulnerable?

One of the reasons that the brain is such an important and vulnerable target is because the cells that make up the brain are particularly high in fat. A lot of the protective sheath of the nerve cells in our brain are very, very fatty, and so the brain tends to accumulate fat, and it can also accumulate these fatty chemicals. 

We have a blood-brain barrier that's supposed to protect the brain against foreign chemicals or foreign bodies, but PFAS can actually — because of their fatty structure — cross the blood-brain barrier. In the brain, the exposure to PFAS can cause changes to how nerve cells, or neurons as we call them, function.

But I'm particularly concerned about development when the brain is organizing and the nerve cells are making connections and the circuits are starting to get hooked up, and we develop our cognitive functions and our other brain functions. We know from research that PFAS can affect those processes.

How long have we known about these effects?

There's actually some very interesting history about PFAS from the scientific perspective. Linda Birnbaum, who was at the EPA for a very long time and moved to the National Institutes of Health — the environmental health agency that's the NIH's main body that does research on things like environmental toxicants — she was studying PFAS and related compounds like 30 years ago, and her initial finding was that it was neurotoxic. In humans, they were showing associations between exposures to PFAS and neurodevelopmental problems in children.

So she really did some of the groundbreaking work on PFAS, and then later she went on to become the director of the agency that funds the kind of research that is now studying the PFAS effects. We've known for decades that PFAS is very detrimental to brain development and that there are strong links to developmental and behavioral problems in children. Those studies really are not controversial. They just keep getting replicated. People keep doing more and more studies where they're looking for links between what chemicals do they find in the bodies of children, and then performance on cognitive tests and other kinds of developmental outcomes. Consistently, it's been shown that PFAS is associated with those problems.

You've argued there's no safe limit for PFAS. With that in mind, at what level in the environment does it start to become a real concern?

We should consider levels that are detectable as a concern. Any level that we can detect, we should be concerned about. Different chemicals have different potencies, so the amount that you need to see an effect is going to vary depending upon the chemical. But I think the point is that we shouldn't be waiting until we see really high levels to start being concerned.

The problem with having a safe level or a threshold is that it assumes that there is some level below which there are no effects. And what we're learning from the science is that for many chemicals, including PFAS, there may not be a safe level. Even very low doses can have biological effects.

Part of the issue is that these chemicals can have effects at different life stages. So exposure during pregnancy or early development can have effects that are different from exposure in adulthood. And so when we're thinking about what is a safe level, we have to think about who is being exposed and when they're being exposed.

So there's no threshold below which you can say, "Oh, well, this is background. This is fine."

Right. I mean, that's the problem with the threshold concept. The threshold concept assumes that there is some level where the body can handle it and there are no adverse effects. But what we're seeing is that even at very low levels, there can be effects on the endocrine system, there can be effects on brain development, there can be effects on fertility.

And the other thing that's important to remember is that we're not exposed to just one chemical. We're exposed to mixtures of chemicals. So even if you have what might be considered a low level of one PFAS chemical, if you're also exposed to other PFAS chemicals or other endocrine-disrupting chemicals, those effects can add up or even multiply.

So it's not just additive, it's potentially synergistic?

It can be synergistic, yes. And that's one of the challenges in trying to establish safe levels, because most of the testing is done on individual chemicals. But in the real world, we're exposed to mixtures.

So when you're looking at contamination sites, you're not just looking at one chemical, you're looking at a whole suite of chemicals that might be interacting in ways that we don't fully understand?

Exactly. And that's why it's so difficult to establish what is a safe level, because we don't know all the interactions. We don't know how these chemicals might be affecting multiple systems in the body. We don't know how the timing of exposure might influence the effects.

And then you add on top of that the fact that some of these chemicals are persistent, so they're building up in our bodies over time. And so what might seem like a low level of exposure on any given day becomes a much higher level over a lifetime of exposure.

And there's no real way to flush them out?

Not effectively, no. Some of them do eventually get excreted, but because they're stored in fat and because they're so persistent, it takes a very, very long time. And during that time, they're continuing to have effects on our biology.

And the half-life — the time it takes for half of the chemical to be eliminated from the body — for some PFAS chemicals can be years. So once you're exposed, it's with you for a very long time.

So you could stop exposure today and still have health effects for years?

Absolutely. And that's one of the reasons why it's so important to prevent exposure in the first place, because once you're exposed, there's not a lot you can do about it.

That's terrifying.

It is concerning. And I think that's why there's been such a push to try to get these chemicals out of the environment, to get them out of products, to find alternatives that are safer.

But the challenge is that we've been using these chemicals for decades, and they're everywhere. They're in the soil, they're in the water, they're in the air. And because they're so persistent, they're going to be with us for a very, very long time.

Forever chemicals, as they say.

And that's not just a catchy phrase — it's actually a pretty accurate description of what we're dealing with.

So when we talk about contamination at a site — I'm looking at North Texas, fracking waste, biosolids — what are we looking at in terms of levels that should be concerning?

Well, I think any detectable level should be concerning. But in terms of what we see at contamination sites, it can be orders of magnitude higher than what we might see in background levels. And those high levels are definitely associated with adverse health effects.

The EPA has set some advisory levels for PFAS in drinking water, but those levels have been revised downward over time as we've learned more about the health effects. And I think they're likely to be revised downward again as we continue to learn more.

So what was considered safe a few years ago is no longer considered safe. And what's considered safe now may not be considered safe in the future.

That's not very reassuring.

No, it's not. But I think it reflects the fact that we're learning more about these chemicals and their effects on health. And as we learn more, we need to be willing to adjust our standards and our regulations.

There's a parallel here with PCBs [chemical compounds, formerly used in industrial and consumer electronic products] right? We thought PCBs were great, and then we realized they were terrible.

Exactly. And I think there are a lot of parallels between PCBs and PFAS. They're both persistent chemicals. They both bioaccumulate. They both have effects on the endocrine system and on brain development.

If we had learned the lesson from PCBs, what would that lesson have been? I mean, it's not just ban PCBs. We've got to think bigger.

The lesson is we can't allow manufacturers to start using chemicals without really doing the deep dive into safety and protections and potential solutions to getting rid of the chemicals if it turns out they're not quite as safe as everybody thought they were. We did not learn that the testing has to happen before things go to the market. We also didn't learn that very low dose exposures need to be taken very seriously.

I've heard this described by a lot of scientists as sort of this colossal, unplanned, unguided, massive experiment on ourselves and the biosphere. Is that a fair way to think about it?

Yeah. The world is being subjected to an experiment that maybe we didn't all agree to.

I think the general public do play a very big role in this. They definitely did for Bisphenol A, which is not persistent, but all the BPA-free stuff now that we have is because of consumers putting pressure on the manufacturers. It seemed like a victory, but there were a lot of replacements to BPA that then went on to the market instead, and those are all chemicals that are just as bad as BPA. So that's sort of the dirty little secret.

Climate change is making everything worse. If you have a week's worth of gentle rain, maybe you don't get a major plume. But if you get that week's worth in an hour — which has been happening in Dallas recently — you get more disease burden. How does climate interact with chemical contamination?

The other thing about scientists is, we tend to be very focused, and it's easy to forget that you can look at one chemical or even a family or group of chemicals, but you also have to lay on top of that all of the other things that are going on in the world, like air pollution and climate change. When you think about heat and chemical reactions, the chemicals that are in the environment are liberated at a much faster rate at higher temperatures.

And enzymatic reactions happen faster at higher temperatures. So we have to take into consideration not only do we have chemicals in our environment, some of which have been kind of just sitting there — like think about the PCBs that are in the soil or in the water — and now the soil is getting hotter and the water is getting hotter, and you have more and more liberation of the chemicals. You also get more conversion into gases, the aerosolization of chemicals. But then you add in something like radioactivity. I hadn't even thought about that one.

You're saying you also have to think about it in a couple of ways. What is the increased temperature and other attendant stressors doing to the specific waste pile? What combinations of chemicals is it driving? What aerosolization? What increased number of unknown chemical reactions between already novel chemicals?

And then also factors like: is there radiation in there? Are there radioactive materials? What is that doing chemically? And then you have to factor in the fact that everybody who's receiving those chemicals has a complicated, changing and increasing disease burden from heat and all the other things that are going on — water pollution, air pollution. Around any kind of complex industrial pollution, those would tend to stack in ways that we don't really understand. There's the impact on the waste and the impact on the person interacting with it.

Yep.

Good Lord. It's like spooky in addition to scary. You can't really assess your risk.

The other thing — I mean, we're doing some of this work in my lab right now — is that what people are exposed to gets passed across generations. So if you're a young couple and you're being exposed to all of this stuff, your sperm and your eggs are getting exposed. So you could see where the offspring may also have an increased disease burden, and there's strong evidence suggesting that that's the case. Very strong evidence from lab studies, and pretty compelling evidence from what little human studies you can really do. 

But if the sperm and egg are affected — I mentioned epigenetics — if their DNA has been modified, either it could be a mutation, but you could also have epigenetic effects. Some of those can actually go across to subsequent generations, to grandchildren and great-grandchildren. So whatever we're doing to the environment right now will be affecting our grandchildren and our great-grandchildren.

And that's assuming that it was cleaned up tomorrow. There would still have been an effect. But these chemicals are in the environment for the time of our children.

Exactly. So what we've already done, that imprint has been laid down for innumerable generations. That doesn't mean we shouldn't stop, right? I mean, I don't want somebody to make the argument, "Well, then who cares if we keep contaminating?" Well, that is going to make it worse.

And I think the point of the research that we're trying to do right now is, of course, we want to understand how these chemicals are affecting biological systems, but by doing that, we also are hoping to be able to identify interventions. So that's kind of the hopeful side — that maybe all is not lost. If we can continue to understand and do research to show, "Okay, this is how it happens, and this is how we can stop that cycle."

This conversation has been edited and condensed for clarity.

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We'll be back soon with more musings on past, future, and all the crises in between. Just remember: what does not live cannot die...