The forever chemicals, or PFAS (Per- and polyfluorinated alkyl substances) represent a large family of highly persistent synthetic chemicals widely used in everything from carpets to non-stick cookware, to firefighting foams and furniture textiles.
They are highly persistent in nature and have been found in the blood and breast milk of people and wildlife globally.
They are linked to cancer, liver damage, decreased fertility, and increased risk of asthma and thyroid disease. How can we reduce our exposure to them?
Support the show
This lecture was recorded by Dr Ian Mudway on 4th December 2023 at Barnard's Inn Hall, London.
The transcript and downloadable versions of the lecture are available from the Gresham College website:
Gresham College has offered free public lectures for over 400 years, thanks to the generosity of our supporters. There are currently over 2,500 lectures free to access. We believe that everyone should have the opportunity to learn from some of the greatest minds. To support Gresham's mission, please consider making a donation: https://gresham.ac.uk/support/
When I was asked to put together this sequence of lectures, one of the things I wanted to do was to try to make sure the topics were were current. Yes, they were. Things within the news. Well, I have to say PFAS has not let me down. Yes. And so I'm gonna touch on many of the new, new stories which have come out in the last six or seven weeks, in fact, during this talk. And the reason I wanted to give a talk about PFAS, the per flu alcohol substances, the Forever Chemicals, is because I, I, I call it living with the forever chemicals.'cause guess what? You are. Yes. I'm looking around this room and every single one of you is wearing clothing which has PFAS in it. Every single one of you will have PFAS Cosing through your veins in your tissues as you sit within this room. And we are the first generations of humans since the 1940s, fifties, sixties onwards who have been exposed to these chemicals. It is new, it is a new entity, a new exposure for the human race. So welcome to the great experiment we're all in and how this will impact on our health. So I have shown this slide in each of the lectures that I have given up to this point. The Gresham College lecture that you're listening to right now is giving you knowledge and insight from one of the world's leading academic experts making it takes a lot of time. But because we want to encourage a love of learning, we think it's well worth it. We never make you pay for lectures. Although donations are needed, we, we ask in return is this, send a link to this lecture to someone you think would benefit. And if you haven't already, click the follow or subscribe button from wherever you are listening right now. Now let's get back to the lecture And it's simply to make the following point, we have made a huge number of novel chemical entities over the last century. And really the number I wanted to flag up here was there's a global inventory of chemicals licensed for manufacture and it's around 360,000 chemicals and combinations of chemicals ready for use. And within the EU probably we've licensed about a hundred thousand of them. And of those, about a quarter of them have been through reach. Now reach is the European registration of valuation authorization, restriction of chemicals act. It's the law. We have to try to make sure that we do not release dangerous chemicals into our environment, which is bad for the environment or bad for our health. And it's quite obvious to see that we are 75% behind where we need to be. And we are getting further away from it, not closer to it. We are making more novel entities than we can cope with. Now that said, we have this big chemical problem, chemical environment that we're all living within. Just imagine. I was to tell you that within that cocktail we have a class of chemicals now 15,000 different chemical entities as of yesterday, our check, the EPA registry, as I was going through this talk, the sort of PFAS registry 10 years ago was 5,000. It's 6,000, it's now 15,000. And those chemicals are now ubiquitous across every single environment on the planet. They are absolutely everywhere. And if I was to tell you that they have extremely long half-lifes within the environment, not forever, but a thousand years, 10,000 years, more or less counts. And if I was to tell you that when they entered your body, they resided and accumulated within your body and built up within your tissues over time and had a long half life and were not eliminated from your body very quickly, that would be potentially a bit concerning. And if I was to tell you that they had potentially, and we'll talk a little bit later on about what the word potentially means in all of this context, being associated with a range of different cancers, testicular kidney cancer, breast cancer associated with cholesterol, ulcerative colitis, suppression of antibody responses to vaccines in children, you might think that we had something that we needed to worry about, certainly something which deserves our attention. And yet I would argue it's probably only been in the last 20 years and probably really within the last five years, that we have become really interested in this group of chemicals and they've become an area of absolute focus. Now the reason for that I think is because it's a nightmare of chemistry. Okay? Uh, you'll see in a second the diversity, the range of names. I am a scientist, I'm also a dyslexic scientist. This is the worst lecture I can ever give. Yes. Basically PFAS science is like number plates dancing in front of your eyes. Just be prepared. I'm gonna mispronounce everything, get the letters completely in the wrong order. That's your, I'm bringing your head and my hand up. One of the reasons I think, and I think there are two reasons why PFAS suddenly began to grab the public imagination. And one is that somebody came along and simplified. It came up with the term, and I still think this is kind of amazing Forever Chemicals was coined in an Washington Post opinion piece in 2018. Yes. That's when this word, this phrase entered our language. And it's kind of a brilliant catchall word to explain the fact that we are making chemicals which enter, enter environment which persist, which are resistance to chemical and enzymatic degradation and which we will be living with for a very long time. In fact, one of the stories of PFAS is that we have stopped producing some of them. The burden we are now living with is what was released over the 50 years before we began to phase them out. And so Joseph Allen's very cleverly switched the debate by focusing on the lifetime of these chemicals as a group and not getting lost in the alphabet soup of PFAS classifications. Now I'm gonna keep this really quite straightforward. Yes. PFAS per polyflor alcohol substances. The two which have been studied the most, the two we know are the most about of the 15,000, most of which we don't know very much about are polyflor octane acid, which I'm gonna call PFOA hopefully most of the time. And per Fluor octane snic acid PFAS, which I'm much happier, I might get right now. Those chemicals were the predominant PFAS used in manufacturing from about the 1950s through to around the 1980s, 1990s in 2000. And we find out why industry in the United States and globally voluntary, voluntarily, as voluntarily as industry ever does, decided to phase out those two compounds because of concerns about the impact on the environment and health. And beneath it I have Gen X and Gen X doesn't refer to people of my vintage, you know, sort of 65 through to 1980. This is the new generation of compounds which came after PFAS. And here I think is a really important point. We regulated out chemicals which were known to cause harm and we replaced them with a new classification and group of chemicals which were essentially really very, very, very similar. Which we didn't regulate 'cause nobody knew whether they were going to cause harm yet. So there's a bit of a story here about innovating new chemicals to avoid regulation, I suppose, to innovating new chemicals which are safe. And we'll see exactly what the consequence of that has been. Now the reason that these chemicals occurred, and I like I gave a talk, it must've been about six weeks ago on, on microplastics. Yes. And I made the observation, the microplastics, it all happened in the last three score years and 10, it's the same story here with with PFAS. It's the same sort of tape timeline. And again, it happens as many things happen with a bit of an accident. There's Roy j Plunkett, a 27-year-old chemist who makes a mistake doing refrigeration gas science and accidentally makes the early Teflon you. So this is how it all sort of kicks off. So day number one is 1938. And then you have these very, very useful structures. We have a carbon backbone where the hydrogen has been substituted with s fluorine. So we have fluorine. So we have carbon fluorine bonds, which are incredibly strong single bonds. Some of the strongest single bonds you can get very firmly, uh, resistant, resistant to degradation. Actually quite good at sort of opposing grease, pushing away moisture. So you have these really tough new molecules which do some fantastically useful things. So here we have a molecule which can be used and can be used to manufacture things with particular uses. Now that's a kind of prototypical structure. Then we begin to see how they begin to branch out. So at the top we have pofa and we have pofa. And then beneath that we have different forms of PFAS, which either have different sort of groupings added to them. Don't worry too much, I'm just showing a lot of stuff is coming. And then it keeps on coming and it keeps on coming and it keeps on coming and it keeps on coming. The forever chemicals, that's what we are going to call them. And we're gonna focus on two of them and then only towards the end reflect on what happened with the new generation of materials when they came through. But they are everywhere because they are so incredibly useful. They're in your non-stick pots and pans. They are in everything which is grease resistance in your little styrofoam. Sort of like burger boxes in your pizza boxes in your takeouts. They will be absolutely, definitely lined with PFAS in all your stain resistant clothing in all of your outdoor clothing, which is water and grease resistant in pesticides in cosmetics. I always find this bizarrely for reasons which I've never understood in dental floss, go figure. Um, in paints, in microwave, cock porn bands, in firefighting foams in personal care products, they are absolutely everywhere because PFAS gave that unique capacity to actually perform a useful function. And it was invented at the time when I think chemistry was having its golden day. Yes. When chemistry post-war was launching and doing exciting things to make everybody's lifes easier than they had been before. And so this all got tied up with this concept of better living through chemistry and somehow in this kind of cell, the consequences or a more holistic view of what these chemicals might do in the long term, not in the now as they were assisting us of our daily lives, but course their whole lifecycle was lost. And PFAS is a bit of a normality tale about exactly how that sort of view of chemicals is a great commercial sort of and lifestyle and time-saving entity perhaps has caused us more problems downstream than we're aware of now. We have all this good stuff so far. Yes. Okay. Certainly it's much easier now to clean our pots and pans. Yes, it's a much easier world. It's straightforward to stay dry and and stain free. And we know that the Forever Chemicals has come along and that's a name when people have got this into their head. But the other thing which I think really pushed PFAS into the public imagination and made people realize that perhaps it wasn't simply a good news story, was this story. So DuPont both gave us Teflon and DuPont also gave us the evidence that we needed to be concerned about PFAS. And this is Robert Billett, who is a lawyer who they famously took up a class action by a community, um, in, and I always get the name of the place wrong, but I think it's Parker's Parker's, it will come to me in a second Parker's bill, something like that. Anyway, it'll come back Western Virginia where there was a big DuPont factory situated next to the Ohio River. Over a long period of time, huge amount of waste from Teflon manufacturing had been disposed of in the land, lots of effluent and entered the rivers. Lots of materials had entered the sort of air. And he was initially approached by a farmer because all his livestock was dying. And through those conversations he began to realize that there were lots of people with health problems within the communities surrounding the DuPont plant. And he began to represent the members of the community in a class action against DuPont, during which he got access to some of the very, very sort of private internal documents on their own research on PFAS, which they'd been undertaking. And it's an interesting tale because it's quite clearly the case that in the 1960s, DuPont and many other and certainly 3M definitely knew that at high concentrations, P-F-A-S-P-F-A-S and PF OA were toxic in classical animal experimentations that was known in the 1970s that they actually measured the concentrations of PFAS and compounds within the blood of workers within the actual factories and demonstrated that it was high. Yes. So they already knew there was an exposure in the workers. They already knew there was information about potential toxic effects, but they didn't do very much about it. And I don't wanna dwell on this for a number of reasons. A 'cause there are many books and many articles which have been written about this particular case. And B, the legalities of speaking about it are quite complicated and need to be handled in a very nuanced fashion. But the reality is that the people living in the vicinity of the factory clearly didn't know that the factory was producing chemicals which are potentially dangerous to human health. Wasn't appreciated. There were clusters of leukemia cases, there were clusters of testicular cancer cases. Questions were being asked. And so Rob Billett managed to get a case and take it all the way through, okay. And win the case. And you at the end, I mean the settlement is, I think it was about 555 million US dollars to about 3,500 plaintiffs who had been affected as a consequence of this. A big potential payout. But more importantly, it led to this realization that PFAS had a negative impact on health. And then that story was interesting. And this is a story which is again in the New York Post and you can go and check that yourself. It took off because they made it into a film. So dark waters with Ruffo allowed people first, first time I think people went to the cinema and heard the word PFAS and Forever Chemicals being mentioned at the same time as the term was beginning to be christened. And then people began to realize there was something going on here. So we have an alignment of things occurring. The topic is getting hot, it's entering public consciousness. And the science is getting kind of interesting because when I say that, it's everywhere. Oh, I mean, it's absolutely everywhere. Okay? It's remarkable how 50 years of production of a chemical entity can disperse around the entire planet in a blink. It's in our rain. In fact, the concentration of PFAS in rainwater, if it was coming out of your tap, would be too high. That's an interesting one. It's actually in the melt waters of the glassier coming down from Everest through the base caps. You can detect it within ice cores taken from the Antarctic ice sheets. You can see it in our rivers, in our seas, in our soils, in our sediments, in the dust by the side of the street, in the particles which are floating in the air. It is absolutely everywhere. This is a ubiquitous chemical entity in our environment. And it has just happened. I find it remarkable in a, in a blink of an eye. Now the next part of this, which suddenly becomes interesting is this. And this is a, this is a study. Look, it's 2001. So the case is going on with DuPont. This is the point at which the American industry is beginning to phase out P thousand P four. And this is one of those wonderful studies where somebody does something which feels really odd, but ends up being slightly brilliant. Yes. In its own way. So this is just a collection of blood and tissue samples from animals collected from around the planet. Yes, penguins and seals from Antarctica, bald eagles from the great likes, river otters from northeastern United States. Just to see whether these chemicals, which we know in the environment are accumulating within the fauna of the planet earth. Now this is the first time this was done. And again here look, we have our two favorites. At the top we have PFAS at the top we have PFO at the bottom. And then we have some sulfated sort of derivatives. And this is kind of what they find. So let's look at the top. We have PFAS in ring, sealed ring seals. Look Baltic, the high B Canadian Arctic, the Norwegian Arctic, the Baltic. We keep on going down, keep on going down, keep on polar bears, in elastic in the liver. We have really high concentrations in the bottom nose, dolphin high concentrations as well. So the PFAS within the environment has dispersed to the far north, to the far south, away from any site of production, away from any site of overt use and is accumulating within the food chain. The concentrations seemingly being higher in animals which are clearly higher in the trophic scale. And then there are other studies which was going to come out. I I, I kind of like the studies from Scandinavia because Scandinavia is nice and clean. So these are studies from Norway and Finland and Sweden and the Pharaoh Islands and Iceland. And here we just have a few PFAS. Here again, here we have P oa. Here we have PFAS. So just the rest of them are just there for interest. What do we have here? But you can see we are measuring it in most of this sample. This is seawater, seawater, seawater, Finland seawater, Denmark seawater Iceland seawater, Finland Lake water, Norway, river water, Iceland, Sweden, sewage effluent bang shoots up. And then over here, if you just check the scale, this goes from Naugh to 17 nanograms. This is now going from zero to 700. These are landfills. This is effluent coming outta the landfills again from sites. And so we can see that this material is within our water and it's leaching out of landfill sites because actually the very things which make PFAS remarkably good at repelling moisture and keeping grease at things make it really good at moving through environmental compartments. So it moves quite freely. Yes, it can escape tremendously well. Okay, so it's in the water, it's in the soil, it's in the fish. This is Cod Sweden, flounder Norway. Go all the way down here to arctic char. We can see how it's accumulating in the marine fish. And over here we have marine mammals, gray seals. Here we have pilot whales. You can see the peaks. And here lower levels, we have the minky whale. So the toothed whale, which is eating the fish is accumulating the minky rail, which is essentially a baline rail is not accumulating. So it's not getting that sort of trophic load. So it's bioaccumulation within the animals on the planet. And again, another paper did the same thing. PFOS here, PFAS zoo plankton, clams shrimps, arctic cord red fish all the way down here to the beluga whale black lead kitty weight Galatia scales. So we're going through things which are small and absorbing all the way things to things which eat, which then eat the, this is, you know, sort of like the classic perfect trail. And this is the lovely graph which shows you how it all sits together. Here we have our PFAS and you can see it's accumulating troph within the animals on bath. So this is around 2004. So by 2004, basically we know the cat's out of the bag. Yes, we know that PFAS is everywhere and we know that it's accumulating within animals within our world. Which raises the next question. What about us? Because we are just part of that cycle, aren't we? You know, we've got industry making consumer goods. We know the consumer goods have PFASs and we know that that's being thrown into landfill sites or burnt, which is going to release these materials or it's just entering the environment passively.'cause there are certain issues with sort of like flame retirement farm, uh, foams that's entering wild animals. It's also entering commercial farmed animals. And then right at the end, at that top of that trophic trail is us. Yes, that's us right at the end. So there's no reason there should have been no reason to believe that we would not be full of PFAS to, and we are not all of us, about 98% of US measurements. So what do we have here? This is the American North American Health and Nutrition examination survey. It's a huge survey. Yeah. So here they're taking blood measurements from around two and a half thousand people and they've taken samples in 1999 to 2000 and they've taken samples 2000 feet, 2004. So that's before the ban of PFOS and pfoa. And after the ban of PF PFOS and pfoa though it wasn't really a complete ban. And what we can see here are nine 12 to 1920 to 39 40 to 59 60 PFAS. And we can see, look, it's in everybody. And if we go across here pfoa, it's in everybody. And actually it falls between 1919 92,000 and 2003 in all cases. So from 29 to 19, from 28 to 18, from 33 to 22. So the ban has kind of worked. It seems as though the levels are beginning to fall down. But there are some interesting things in here as well. Men have higher concentrations of PFAS than women. Uh, poor ethnic groups seem to have higher concentrations. But nevertheless, what we are seeing is evidence that the PFAS, which has been released into the environment, has made its way to us, okay? For the first time in human history, that's and both interesting and worrying at the same time. Now this survey is regular. So we can actually look at what has happened. So again, from 19 19 9 to 2000 all the way up to 2018 when they took some time off for various reasons, the next wave and we can see P-F-A-S-P four and you can see the concentrations are falling dramatically. What you can see here is what's happening to the new PFAS materials, which are being introduced in the environments as alternative replacements. Because at this point they're not really all being measured in a way that we can actually quantify them. So let's say those are going down. But there are big questions about what's going on with the replacement PFAS. Now this is interesting for a number of reasons. I myself study air pollution and I spend a lot of time trying to work out how I work out, how much air pollution maybe you've been exposed to or you've been exposed to using complicated models and it's a bit of a proxy. Yes. And I always sit there going, wouldn't it be great if I had an internal biomarker of what you had been exposed to? This is an internal biomarker. Yes, this is as good as it gets. I want to know what you've been exposed to. I can tell what you've been exposed to. We have a little caveat yes in that this doesn't tell me what you've been exposed to today. Because the half life of PFAS in your body ranges from two to six years depending on the nature of it. For the very new ones, it's a bit shorter. But this is kind of like a cumulative load within your body. Now if it was a going to work as a biomarker, it should pass the common sense test. Yes. And this for me is the common sense test. Looking at PF OA and it's asking a simple question, who should have the highest concentrations of PF OA in their blood? Guess who? It's always gonna be? The person at the factory working on the factory floor manufacturing the stuff. Yes, they're at the top. Yes. So we can see they have the highest concentration. Then the people we'd be concerned with next would be people who live in communities where we know there's already contamination in their watercourse or in the land. And that's in deep blue. And we can see the deep blue, they're quite high. And then the general US population in the light blue sort of bars. And we can see that's 1990 to 2000 and that's 1970 to 1980. And that's showing that downward trajectory. So as a biomarker, this seems to be working and it works for PFOA and it works for PFOS. So this is useful because once you have this, we can begin to ask questions about how these levels relate to how or to adverse effects within a given individual. Now this is still only looking at blood. And you know that's not gonna give you the whole story because once PFAS is taken off with your body, it very rapidly binds to the circulating proteins within your blood and then it redistributes to the solid organs in your body. And so you can actually see this, again, this is a study, it's 99 autopsy samples taken from individuals and it's just brain, bone, kidney, liver, lung. Here we have a range of PFAS. The take home message is it's in every tissue. Yes. It's not just in the blood. It has gone everywhere. It's in all solid organs. Rich organ. It goes to, depends on the PFAS to a certain extent, but it is there. It's in the blood, it's in the tissues. Hay, it's even in your bones. Yes. As a kind of like an cumulative sink. Fine, then we can move on to the next thing which we might be concerned of. If it's circulating in the mother's blood, would it pass with the placenta and reach the fetus? And the answer to that unfortunately is a very resounding yes. So this is, this is only from this year. It was an analysis of 40 independent studies which looked at cord blood concentrations of PFAS in children. Many of the studies correlated the cord blood concentrations of PFAS with the maternal blood levels and the relationship was really incredibly strong. So the mother's PAS burden was being transferred to the child. Yes. It's 30,000 blood samples. It's pretty robust when you pull it all together. Yes. So we now have a transgenerational transfer of a persistent chemical by accumulating within the human body from the mother to the child. We can continue breastfeeding versus formula feeding. Clearly when you're breastfeeding you mobilize reserves from your body, including the stored PFAS within your tissues. So breastfeeding is associated with transfer of stored PFAS from the mother to the child. And if that feels a bit strange, well here's a graph of a look. This is a, you don't need to look at this. Each of those sort of like it's a study. There are lots of studies there. Those studies are from all around the world. They're looking at PFOA concentrations in breast milk. It's in all breast milk samples. And this dotted line here is the dotted line that if you had made that measurement in tap water, you would've had to do an investigation to make sure that it was safe. Okay? So at the top there was some three little graybars. That's formula milk. So it's not really a huge amount, it's everywhere. It's evening in milk formula. And it's the same thing with PFAS. So the take home message is the PFAS in the blood of the mother is transferred to the child breastfeeding. The child transfers stored PFAS in the mother to the child as well. The burden passes from one generation to the next. And again, this is just to illustrate that. But again here we have P thousand P four, again this is looking in breast milk, but down here actually we have some of the new compounds, some of those replacement compounds which are been introduced because we know these are dangerous and these have been reduced as replacements because they do the job and nobody's told us they're dangerous yet. So just bear in mind, the new generation of PFAS molecules are appearing also in breast milk. They seem to have a shorter half life in the plasma 'cause they've got shorter carbon chain structures, but they are still there. And I can illustrate why that's concerning in the next slide because this is a bit like that slide from the NHANES study, which showed that plasma concentrations of PFAS was falling with time only. Now we're looking at PFAS and PFOA concentrations in breast milk and the breast milk samples from 95 through to 2020. And you can see as PFAS is being faced out, it is falling in the breast milk. And so is PFO not the best progression line in the world, but it still seems to be significant. But this is the one which is the arresting one. This is our new generation. And as one goes down, the other one goes up. We know quite a lot I think about the toxicity of these two. We know very little next to nothing about the toxicity of this new generation. The little we do know tells us they're probably as toxic. Yes. So if we've replaced something we know is bad with something which we just have a lack of knowledge about. So given that we know there are these exposures, it should be therefore possible to begin to unpick what some of the associated health effects are by association chemical load versus adverse effect. Now this is restricted by measurements. So these studies are quite small. But I can go through here the things which have been associated with PFAS and the internal dose of PFAS within the human body. Uh, certainly there seems to be a relationship between circulating levels of PFAS and fibro dysregulation. That certainly seems to be the case. Um, there's a seems to be a pretty robust association with hypercholesterolemia, um, and blood pressure, which is actually seen even relatively young liver damage through enzymes. Increased risks of kidney cancer and testicular cancer, low birth weight, uh, again related to sort of problems of the placenta. And there's one here, which is fascinating, reduced responses to vaccines. I wanna talk a bit about that because that really reframes a lot of the issues. And then in there we have a lot of things which are not in bold and they're things which people have seen, but it hasn't yet reached a level of sort of statistical certainty. And here we have low sperm count preeclampsia, hypertension during pregnancy, uh, inflammatory bowel disease for example. So there's lots of evidence from statistical association that the level of PFAS in the body is associated with this. But we do have these issues about absorption, distribution, metabolism's. Interesting. These chemicals are not metabolized yet. They stay unmetabolized in the body, residing in the tissues bound to protein. So they don't really get detoxified and they get excreted in the urine. But relatively slowly at the bottom here I've put sensitivity and I've put that there next to dose.'cause you know, everything in my world is about dose. Yes. It's about whether you, there's enough of the stuff to cause an adverse effect. Here is the, the issue of sensitivity. If everybody has PFAS in their body, absolutely everybody and only not 0.0001% of people are vulnerable. Yes. That percentage of the global population is a very, very big number. So as soon as a chemical exposure affects everybody, yes the effect, the toxicity doesn't have to be massive, which actually begin to have scalable effects and significant effects on public health. It's something which people often struggle to get. They're very used to the idea of, you know, the really big hazard which has a big effect immediately when you start looking at these low level chemical exposures, it becomes a much more subtle effect. Now the thing about this is we do know a little bit more than just the clever statistical jiggery povy. Yes, we do know some of the mechanisms and we do have some clues on what's going on. We do know that in the placenta there are problems with implantation. We can demonstrate both experimentally in animals and in human samples that there's thyroid defunction, increased thyroid stimulating hormone. We can demonstrate oxidative stress and DNA damage occurring within the liver. So we can see certain biological events occurring in tissues which are adverse. So it's not just association and statistics, there is toxicology here which is going on, which is coherent, very often quite coherent. But the issue of what is a safe dose is something which has really become a bit of a, an issue in real time. And I have to do this 'cause I still find this fascinating when we were talking about the trophic accumulation of PFAS, I showed you data from pilot whales in the Pharaoh aisles and we are back in the Pharaoh aisles now because the Pharaoh isles and scientists in the Pharaoh aisles have done some of the most remarkable research, which has demonstrated potentially some of the most important health impacts of how PFAS is likely to impact on human health. And this is fascinating 'cause we are miles from the factory, from the source from where you would think yes there would be any real source of PFAS accumulation in this population. This is the Pharaoh Isles, but they do eat quite a lot of seal and they do eat quite a lot of whale. And so they are right at the end the sharp pointy, bit of a trophic pyramid. Yes, they are likely to accumulate. This paper was brought out um, in 2012. It's quite old, but many of the guidelines about what people think is a safe level comes from this paper and it's really very elegant. So they looked at 560 ish live singleton births and then they measured the PFAS concentration in the mother and then the PFAS concentration within the blood of the child. And then at five and seven years old post immunization, they looked at their antibody response to an to diptheria and to TEUs. And what they found was quite, I still think it's really remarkable if you look at PFOS, they found that by the age of five a twofold greater concentration of PFAS exposure in the child, which correlated beautifully with the concentration of the mother at birth, was associated with a 40% reduction in antibody Titus. That's chunky. That's a big difference. And when they looked at PFAS and PFAS and they again, they looked at age of five and they looked for who was falling beneath a clinically relevant protection after the actual vaccination. There's a twofold and a fourfold difference for PFAS and P pfoa. These are huge differences. So this is telling us that the early life exposure to PFAS is having an impairing effect on the immune system in terms of if you like immune training upon vaccination, it is doing something to the immune system. And here this is PFAS in the child at the age of five, this is the antibody response at the age of seven. And you can see there's a dose response relationship and you see it here for inferior. And you can see it here for tetanus. It gets a bit wobbly at the end because there are a few individuals at the end. So the uncertainty increases a bit. This means the, the range we're looking at here is between, what should we say, about 10 to about 20 nanograms per mil having a significant effect on a really, really meaningful endpoint. And what's interesting is they tracked this response through adolescents and it stays exactly the same in this cohort of children. But hey, nothing is real in science unless somebody replicates it Yes and replicates it. And it doesn't have to be exactly the same type of study, but it needs to have some sort of commonality. So here's an interesting one. This is a German study. Again, it's looking at antibody responses to the accumulation. This case it's pfoa. So we have 101 dots here and they're paired Muslim and child. Yes. Okay. The reds the child, the blue is the mother. This group over here are formula fed babies. And this group over here are babies who've been breastfed. So we can see as the mothers of breastfeeding, their blood levels of the PAS is decreasing and the children's levels of PAS are increasing dramatically because of the breastfeeding itself. So we have this pattern here. They looked at antibody responses at one year after influenza, inferior and tetanus injections, again vaccinations. And again, this is all plateau, but between 12 and 25 it begins to go down. This is for influenza. The same pattern now for, I think that must be tetanus. And then the final one is for DIP phe. So they're, they're replicating this kind of impairment of the immune, the adaptive immune system. And they did something fantastically elegant in this study and they took blood from the babies, they isolated the immune cells lymphocytes from the actual blood and then they challenge those lymphocytes with the actual antigens within the vaccine. And what they found was if you took sort of like the lymphocytes from the children with high PFAS, there was almost a reduction of 50%, 50 to 60% of the capacity of those cells to produce a compound known as interferon gamma. So actually the PFAS was interfering with the antiviral immune response and you could demonstrate that ex vivo in a test tube using their cells. And you could see the actual physical association there. So this is really fascinating and the levels are quite low and you're looking at something here in early life which is gonna have a significant ramification for their long-term health in terms of their immune development. So there you have the epi, it was then compared against all of the toxicology data by the US National Toxicological Program. This report is huge. Yes. Very, very detailed conclusions. Hey, guess what folks? PFAS seems to be having a damaging effect on children's immune development that I think is some of the strongest, most persuasive data out there at the present moment in time that we should be concerned about these compounds in terms of how they are affecting our children in our society. So where were we? Let's go back to PFAS. So if we started, it's developed, you know, B War, then in the war, all of these PFAS are used for military purposes. And then after the war, all of that production is converted into consumer products for money. And then it becomes a really big money making expertise. We have exploitation along the ways. We have some discoveries that there might be something bad going on, but nobody in industry wants to tell the regulators about it. So nothing gets done. We get all the way through to the two thousands. Um, people begin to realize there's something going on. So they begin to phase out the old PFAS, but they introduce these new alternatives and it's really only from about 2010 people in the wider society begin to get very concerned about these things. And why have they got concerned?'cause it's everywhere now. It's in our rivers, now it's in our tap water in the states. But here as well, a recent study by the Royal Society of Chemistry demonstrated that when you took samples from 17 water source areas, feeding our water for our homes, all of them had really alarming levels of PFAS in them. And give you some sort of illustrations here. This is just a sample of PFAS monitoring from around the United Kingdom. And you know that's London. London has about, this is the Thames, it's about 4,000 in the center. As you go out towards the estuary, it goes down to round 1000 sort of, you know, microphones. These are way off the top. So look, we have a problem. Yes, we have problems with PFAS. People are beginning to explore how to deal with it. Here's the other part of the equation. It's not cheap. And I can give you an illustration of how it is not cheap because after the case they won in Virginia against DuPont, they had a secondary class action which only settled a couple of months ago. Yes. And this was really for DuPont and 3M to pay the costs to clean up the mess they had made of the environment and the watercourse in the United States. And that court case, which they have just lost, means they have to pay $10.3 billion in order to do the cleanup. The cleanup of this stuff is not cheap. Last week the Pentagon announced that the cleanup costs of 50 military sites within America, which was heavily contaminated because of flame retired and foam is now somewhere in the order of 31 to 50 billion US dollars. Yeah. So when I think about the lifecycle and thinking about what things cost, these are the costs people didn't really anticipate. So all of this is going on and as all of this is going on and countries are thinking about how they're going to regulate and put in place regulations in order to restrict the amount of PFAS in our water, what we have in the United Kingdom are guidelines. Okay. And so again, the war society has kind of said maybe we should a bit of a better job of guidelines. And actually there's something interesting going on here. Currently, the guideline in the United Kingdom goes like this. Do you have less than 10 nanograms per liter of A-P-F-A-S? If you do, it's a low risk. If it goes up to about 90, it's medium risk. If it goes about a hundred, it's high risk just one. But there isn't just one. And they often operate through exactly the same mode of action. And there's no mechanism in our system to add them together. You just treat them all as individual entities. If they, if you had a hundred and they were all below 10, it would be fine. Yes, Europe does something completely different. They take the 20 most common PFAS and they have a collective aggregate dose which they regulate. The US actually have individual limits, but at a very, very low level of four nanograms per liter. So less than half of what our proposed is and what the raw cellular chemistry is proposing, which I think is quite sensible, is a halfway house the best of both worlds. Keeping our single standard but also having a collective standard. So we do begin to aggregate this up. I think this is really one of the most sensible things I've heard in a very, very long time in terms of thinking about this. You cannot, we cannot regulate PFAS one at a time. We cannot do toxicological testing on PFAS one at a time. We have to find ways of doing this by class. And we need to find ways of aggregating and assessing the risk of the mixture. Now how do you get rid of the stuff? Whatever I've just said, it's here. Yeah. It was all released between 1950 and 2000 or the poppa or the POAs and it's still there. Yes. And it's not gonna degrade for a hundred thousand years. So we've got a cleanup exercise Yes to do. Certainly. How can we get rid of it? Well there are people beginning to look at this, looking at, if you like, filtration, reverse osmosis activated charcoal filters to try to remove some of the actual PFAS from our water. My only issue of this is what do you do with the substrate after the cleanup? Yes. You still have the stuff, you've got to dispose of it. You still have the waste. There are other people who are attempting to degrade it to actually get fracture. These carbine, these carbon flowed bonds through photocatalysis through radical reactions, fungi, bacteria, thermal lysis. A whole range of technologies are beginning to be developed. But a lot of these technologies seem to be quite promising in the lab. Very few of them have been scaled up yet to the sort of level that we need to address the problem. So I have a few final thoughts. First. This I think is a quote from Ian Cousins. He's a professor of environmental chemistry in Stockholm, who is one of the guys trying to work out how to, if you like, remediate, get rid of the PAS within our environment. And he came up with this wonderful comment and he said the toxicology of these chemicals is not yet fully understood. Uh, but uh, we know that everywhere and they shouldn't be. For me, this is like one of the nicest, cleanest examples of the precautionary principle. Yes. I am so fed up of being told that we can only get rid of stuff if we can say it's dangerous, but not because we have to prove it's safe to begin with. And so that I think is a really key issue. And the reason I think it's a key issue is it's not just PFAS, it's our whole chemical environment. I've stolen this quote, um, again from Alan from Harvard because he made this wonderful observation that what we do in chemical regulation is we play an elaborate game of whack-a-mole. Yes. We identify something, it's bad, we whack it and then the next compound bounces up. We innovate to defeat and get around regulations. We do not innovate to create safe materials. I think this is what we need to do in the 21st century. I think we need to beginning to think about material chemistry almost in the same way that we think about pharma. Yes. In terms of actually doing good preclinical studies to make sure that the materials we put into the environment are safe and thinking about their full fate. What happens at the end of the day. Um, and the reason for that is because I'm an environment mental health scientist. I believe in the precautionary principle and I think we've been rather cavalier over the lev last 70 years in sacrificing the precautionary principle. And we have stumbled into a whole series of situations which have exposed both us and our future generations and our future generations to health burdens but also to degraded environment and a poorer quality of life. I think that's unacceptable. Thank you. Thank you Ian. Um, a huge number of questions. You'd be delighted to hear <laugh>. Um, Did I, he didn't get the codes right. The um, it's a striking thing here that you've got a chemical industry, which for the last X years is shoving up new moles for you and, um, the culture of that creative industry. At the same time as we have a huge number of politicians expressing a need for a bonfire of the regulations is actually an accelerant of risk rather than a decelerate of risk. Wouldn't you argue? So how do we alter the, um, manufacturing and political framework in which we, who, who holds the influence do you think? The person who controls the money. Yes. I'm afraid. And so until those individuals who are cleverly thinking of innovative ways to get the next mole to poke its head up for the whole realize that that's short term and downstream they're gonna get hit with a 51 US billion dollar lawsuit, which they have to deal with and their companies outta business. That they have to realize that yes, they have to pay those costs. Yes. And those costs have to be, and if we can get that cost. Now the problem is of course that we live in a political milieu and our political milieu cycles around every five years. Yes. And it doesn't lend itself towards good strategic decisions. I would quite like an organization like the Office of Budget responsibility to be responsible for taking long-term strategic financial risk assessments for the United Kingdom, including in terms of industry, so that they think about these things and then when people go and say, this is our budget, this is our plan, this is our deregulatory framework, they go that financially is suicide. So it's like forcing them to carry the cost of cleanup or carry avoiding the cost of manufacturing. Yeah, You have to, I mean the cost of cleanup can't be handed to the people who have suffered the disadvantage and have had none of the profits yet, which is currently how the system operates. So Two, two household questions. Any point in buying a filter, do any of them work? And would you buy one Water filters? Yeah. The specific ones that are now being sold advertised to filter out PFAS. So I was gonna have a slide, um, about water filters and I read the papers and at the end of the papers, um, I was very confused <laugh> because some of them work and some of them don't seem to work terribly well. Um, and I couldn't give you a good coherent answer to the question, but who regulates them? Who regulates the people who make the water filters to make sure the water filters fulfill the requirements they're meant to fulfill? One of the big problems we have is the industry sometimes is allowed to regulate itself in things which actually begin to cross over into health. And I think this is a really interesting debate. If you be, if you engineer, if you get a filter, you say this filter will remove harmful chemicals which are harmful for you and your unborn child. Is that filter now a medical device? I dunno.'cause if it's a medical device, it's an entirely different regulatory framework and they've gotta prove it works. Yes. And and You made a point about those filters are actually accumulating the stuff on the filter which you then throw away somehow. Yeah, exactly. So there's, they they're actually adding to the pool or not adding to it. They're maintaining the pool. Yeah. And and you can't, the substrate matters. Yes. Yeah. We have a huge, we have made a mess of our planet sometimes by dealing with one calamity and creating a new calamity, solving that calamity. And it kind of scales up. It's a bit like what, what's gonna happen toward the, what's gonna happen to all the electric car batteries? What's going to happen to all the filters? What's gonna happen? We have to have a plan. We can't just have a short term fix. We have to think about this in the long term. So if you're an ultra cautious parent living in London at the moment, how do you, is there anything you can do to protect your children from exposure to these chemicals? Or are we stuck because they're already out there, we can't get with them? Do you know there's again, I came across a list of regulations. Yes. Um, filter your water. If you can get good filter, keep your fingers crossed. Um, make sure you are, you know, you are not using a Teflon fing pan. I don't quite believe. And if your Teflon F plan is fine, it's not damaged, it should be. Okay. Think about the clothes you're wearing. Think about the cosmetics you are using because many of those have PFAS within them. Yes. So I think you could probably reduce your exposure. I I did see, um, a, a really interesting documentary in preparing for this with somebody was, you know, went and had their sort of, their blood taken and, you know, thought they were gonna have a really low, uh, PAS concentration because they, they live a very virtuous and potentially slightly boring life only to discover that their concentrations were off the scale. And after much sort of by debating it's because they scotch guarded it all their children's shoes all the way through, through education. And Scotchguard is absolutely full of, you know, PFOA. So, so in a sense, you know, you, I think you just have to be a bit cautious with it. Not eating high predators and eating, avoiding avoiding whales and seals. Clearly. That's a very good idea.<laugh>. Um, and we, there was one question, uh, which I shared with you earlier on, which I think is quite interesting. One, are there any studies that, um, PFASs and PFE in medical devices implanted in your body continue to give off high concentrations of this stuff? I'm gonna flick it around a bit. Yes. Um, 'cause if you have a medical device in your body, you probably need it. Yes. And this is one of those situations where some of the characteristics of PFAS are uniquely important in the body to not have clotting, for example, clotting responses. For example, I know the American Chemical Society has kind of flagged this up in terms of medical devices 'cause they're going Okay, we can, we just have a little bit of nuance in terms of the regulation of PFAS. So that where PFAS materials are absolutely essential for maintaining individuals have, because they're also used as propellants, you know, in, in sort of like asthma pumps to a certain extent.'cause they have unique properties. So somehow they've gotta get the balance right. I'm not, I mean, although I always say regulation is a good thing. I think regulation should be smart. Yes. And informed and nuanced at the edges. Medical devices are one of those things. If the question is should we be concerned because the health effects of a pacemaker implanted in your chest from PFAS is something you worry about. I think it's the least of your problems and you should be very grateful you have a pacemaker. I didn't get to, um, but just before I open the questions to the floor, I, I didn't really understand whether we're in an irreversible trend that these things are still going up irrespective of everything we've done to try and regulate it. Are they still going up, in other words, more moles than wacky? Are we still seeing rising? Yeah, It's still rising. We're still innovating and we're still making new stuff. But the question is, have we replaced a mole? Yeah. With 20 volts? Yeah. Yes. So, and can we add them together just to 20 mos equal one mole? How did that happen? But you know what I mean? It's kind of like we now have a greater diversity of things to measure as opposed to when we started off and we just had a few compounds and we could measure them. Yes. But the graph I showed you with breast milk where you can show, you know, PFSO and PFOA going down, but at the same time, all the new generation of PFAS are going in the other direction tells me that we kind of have to probably be thinking about how much of that we can phase out. Last question from online was do you have to have fluoride in this compound for them to be forever chemicals or are there non fluoride con fluoride containing ever for chemicals? Yes, You can, you can have other combinations which are equally as as stable. There are other options. There are other sort of halogen you can throw in. Um, no, no, it's no. But I think kind of what we would like to have are not quite ever chemicals. Not quite everywhere. Thank you for a fascinating talk can you tell us if, if it has a half-life within us, this, these chemicals, the PFASs, do they actually break down and they don't break down so there's no, there's no way of destroying them or degrading them or they, they, they really are stable forever. Probably not forever, but they certainly, we eliminate them. Unmetabolized, yes, probably conjugated to other molecules, but they're still unbroken down. We haven't broken, our metabolism isn't breaking those carbon flowin bonds. We are then just passing them back into the environment where they will remain. But is it possible for A bacteria perhaps to do it some form of bacterial back Breakdown? I think if we, I think there were people working on engineering new generations of back. I don't think the bacteria we have will, unless, I mean, I'm the wrong person to ask be should be asking Robin that question. We'll ask him. We'll ask that question. But I do think microbiology has a role to play both fungi and bacteria. But I suspect we're gonna have to do some genetic modification to configure them to the problems that we have. A couple of quick, quick questions. So that's okay. Is formula milk better than the breastfeeding milk? And what type of, uh, frying pans are safe? Like non-stick ones? Are they safe or not? And why? The UK regulation is lagging behind to what's happening in EU and the US Why we are not adopting the best practices. Thanks. So even with what I've shown you, the health advice would still be breastfeed <laugh>. Yes. Even with that data. Yes. It's, that's the still the advice is still that the benefits of breastfeeding outweigh Yes. The non-breast feeding. But I understand the concern. Yes. I think people are always quite surprised when they see quite how much PFAS transfer happens in breast milk. It is, it it's more alarming than I think it, it, it, it seems, but I would never encourage somebody not to breastfe.'cause there are so many other benefits frying pans. The evidence seems to be, have new ones as the moment they're damaged. Don't use the mes <laugh>, then they begin to out gas. Yes. And then you have problems with uh, PFAS. Your third question was, ah, well that's, that's <laugh>. What's the polite answer to that? Um, could, could you repeat the question?'cause I don't think people, uh, the question is why, why is the United Kingdom so out of whack with Europe and the United States? And I think the best thing I can say is because the United Kingdom has decided to Do things its own way, it's very tactful, <laugh>. I mean, not on that tact thing. Note not mentioning major political crises over the last few years, or government policy for 14 years. I think we should stop. Thank the audience very much, but particularly Ian, thank you very much for an ex Thank you.