Episode Transcript
[00:00:00] This podcast is brought to you by the GOSH Learning Academy.
Hello and welcome to this, Our fourth series of GOSH Pods Goes Green. In this series, we'll be exploring plastics in healthcare. I'm Becca Elson, a doctor and Chief Sustainability Officer's clinical fellow at GOSH. Today I'm really pleased to say that we're joined by Dr. Olwenn Martin, an Associate Professor in Health and Environment at University College London, and she's come to talk to me about the health implications of plastics and the chemicals associated with them.
Can you tell us a little bit about yourself and your role?
So I'm, I'm a teaching and research academic. So my teaching is related to health and the environment. I'm interested in the triple planetary crisis on the whole, but most of my research work has been related to pollution and more specifically chemical [00:01:00] pollution.
My research is desk based. I'm not in the lab, so I work, I've always worked at the interface between science and policy, so looking at the scientific evidence and how that then gets translated into chemical policy or other environmental policies.
Really interesting. I'd like to start by asking you a personal question. What was your trigger point? What was that moment when you realised, we really have a climate and health emergency? And you really felt an urgency to act?
Yes. I've been trying to think about if there was a trigger point. I think something, the climate crisis, well, it was not necessarily a crisis at the time, but I was aware of greenhouse gas even growing up. That's something I was interested in. But I think the viewpoint or, or how this is how we feel about it as has changed. So it's something I've been aware of for a very long time and through my [00:02:00] studies as well. As someone who grew up in the eighties, I think we were very optimistic. We saw the Berlin Wall fall or we just were expecting things. So we had issues, but we were expecting things could get better. And there's been a number of political events that means that we see things slightly slightly differently or it hasn't happened. It's just something that has built up for a very long time. We could do something about this and we still can.
But we've really shrunk that window of, of opportunity. And maybe it's a little bit more recent that I, in terms of the health… it being a health crisis, I think that may have come in the last few years or even in the last few summers when you really start thinking on a personal level when you see some of these heat waves and you see that, elderly people may be particularly vulnerable. I'm thinking, you know, in a decade or two, this will be me. It's [00:03:00] no longer something that's going to happen to my child or something like that. This will affect me in my lifetime. Yeah, so I, yeah, I think that's, that's relatively recent that it's just like, it's, the pressure is building.
Yeah, absolutely. It's really starting to hit home, isn't it? Yes, it truly is on our doorstep now.
Yes.
So we're seeing more information in the media about microplastics and nanoplastics, and we know that there's increasing research in how some of our medical products will be shedding or leaching them, which we suspect might have long-term health implications for patients. Yet we haven't really heard much about endocrine disruptors. What are EDCs and what do they, where do they come from?
Yeah, I, I find it quite interesting that microplastics do sort of trigger this public response. Very much. Like I said, there's a lot of worry about those and EDCs have been known about for, for much longer. It's just really a property of, of some of the chemicals that [00:04:00] surround us. So we have, one of our communication system within our body is the hormonal system, the endocrine system. And this just refers to chemicals that can somehow interfere with that communication system in, in different ways.
Either they, they lock in with some of the receptors on hormones, but there's also different ways in which they can modify the amount of hormones that goes through our bodies. Some of these may be natural. I was just re-looking at the example of, sheep grazing on red clover, And actually found that some of them, The fact that it may make them infertile has been kind of debunked. Or some farmers recently I've, I've looked at, instead of feeding them just on pasturised, just red clover there's like 18% red clover and it has actually beneficial effects. So some of these are contained in plants, phytoestrogens, and generally in reasonable amounts, normally sought to be [00:05:00] beneficial for health. And then you have others that are synthetic chemicals. And they can be used for multiple uses. It doesn't necessarily refer to a specific use or a sub specific type of chemicals. When I was starting my doctoral research, I remember reading a paper that said that Bisphenol, for example, no, the oestrogen receptor is promiscuous. Which was an interesting way of putting it. But these are long evolved communication systems across the, the natural world. And they. And I've not checked if this, but they were sort of saying that because the oestrogen is, has been there for, for a very long time. That's why it's able, and it's one of the early system, it's able to bind to a lot of different molecules.
Which I, I dunno, I thought that was interesting. At the time. So they can be. Many synthetic chemicals they [00:06:00] interfere with the hormone system. So sometimes the way they interfere is, is not as easily predictable as more of it more response. They can have what we call non monotonic dose responses, or they can be beneficial… well I dunno about synthetic chemicals, I think it becomes an, an ethical question before for them. Natural ones, they can be beneficial at certain levels, but then they become problematic if you have too much of it. Some pesticides can be or biocides, can be endocrine disruptors. Some pharmaceuticals are, you know, intentionally acting on hormones.
You have some in cosmetics and some of the plastic chemicals that be used in almost every product that is surrounding us. There's some kind of, of polymer or plastics including in in toys. Et cetera. So it doesn't necessarily, they're not easily classified as very specific chemical structure or specific use of [00:07:00] chemicals.
Yeah. It sounds like there's a huge, huge range of them. So how do these endocrine disrupting chemicals get into the body? You've talked a little bit about them being in natural substances like clover, so I assume we can kind of ingest some of them, but are there other routes that they can get into our body?
Yes, it will be dependent on, on the use of, of that of that chemical. So they can be through all the normal roots. So you could inhale them some, some of the polyaromatic hydrocarbons, which are air pollutants are Endocrine disruptors. So you could inhale them, you could ingest them with, with food. You could put them on your skins if they're cosmetics and they could be absorbed through skins or if they're in kind of, if they're pharmaceuticals et cetera, they, you could directly inject them. So there's not really a root that's not that we don't get. I think because of the multitude of uses, you [00:08:00] also have a lot of different roots which would get exposed.
So I know that our bodies have natural barriers like mucus and skin that protect us against some pollutants and other compounds. But are these at all effective in preventing the absorption of EDCs?
So thinking of, of different barriers. I think it will depend to some extent on, on the chemistry of individual compounds.
And when I was thinking about that, I think we, we know that we are being exposed. So, so they do get through. When, when I was studying my first degree with chemistry and I did some pharmacology, we were learning about the blood brain barrier, we were learning about the placental barriers. That's we're supposed to be quite effective at protecting, the brain or the placenta, the foetus respectively from chemical exposures. And as science has evolved and we've learned more, we found that all of these barriers are quite [00:09:00] porous. So they have been in the UK, we are part of this still… there been huge human biomonitoring programmes, where they've, for limited number of chemicals, they've measured exposure of, of people to some chemicals, some of which are endocrine disrupting chemicals and we know there's widespread exposure. So even if some of these barriers stop, some of it, they don't stop all of it.
Yes. It sounds like there's still a lot getting through. So you talked a little bit about the oestrogen receptors but what do we currently know about the potential implications for long-term health? Are there any groups of individuals that are particularly at risk?
So hormones do two things in a way, and that was part of some of the scientific controversy for a very long time. So hormones are there to sort of when you are grown, when you're an adult, they have maintained status quo.
So if you've got [00:10:00] something that slightly disturbs your, your, the system, it will bring it back to, to normal. And that's why we thought that, you know some of these chemicals, that's fine. The, the system will be, will work, recover to some eventually to some extent, but they also play a crucial role during development and at certain periods. Where there they can sort of part, they're part of the orchestration of, of development. So some of the critical, what we call the critical windows of exposure, would be in utero for, for the foetus during pregnancy. Because that's where sort of knocking some hormones at very specific times slightly off may set development a slightly different trajectory.
And you have other time in someone's life where hormones are important. So you have a mini puberty just after shortly after birth. You have [00:11:00] puberty itself and periods of quite rapid growth. And for women, you have pregnancy and peri menopause and postmenopausal periods as well, where hormones do play more than their usual role, role of maintaining the, the status quo.
In terms of what we know of the effects, I think evidence comes from, from different lines of evidence. We have, we would have some understanding of some of the mechanisms. So what may happen at the, the scale of a receptor or a cell or something, understanding how, what is actually happening and how that is involving hormones in some way.
And then normally they will have some kind of animal experiment to check that that is happening. What you see, like a very small scale or the scale of, a cell is happening in a whole organism. And then we have epidemiology which is studies of looking at what's happening with human diseases.
And there you see an [00:12:00] association maybe with, with some exposures and the type of effects. So, so globally what we are seeing with a, with a shift to more modern lifestyle is that we've got really good at dealing with some infectious diseases, but you have increasing non-communicable diseases.
And may, well some or, or most of those add some kind of, hormonal element to them. So the type of effects that we worried about are these non-communicable diseases that we see rising the world over. So some of them will be related to the development of the brain. So I know you might be a little bit controversial to talk about the role of chemical in a autism spectrum disorder after what's happened in, in America or, attention deficit hyperactivity disorder, ADHD. But thyroid hormones in particular have an important role to play in the [00:13:00] development of the brain and chemical exposures could, could have an influence on that. And as I was saying earlier, the blood brain barrier is not as much as the barrier as we thought.
Of course when EDCs were first discovered, people were thinking of the reproductive hormones. So they are EDCs have been associated with effects on both male and and females. So men and women's reproductive health. There are some types of cancers that have hormonal component particularly breast cancers in women or prostate cancers in men.
Something I was personally a little bit sceptical about when I first started learning about those was their role in Cardiometabolic Health. And I think there is good evidence now that some chemicals can be what we call obesogens and have a, an impact on, body mass index but also diabetes and this type of things.
And that's when we started [00:14:00] getting interested in cardiac health as well, because they may, they may also play a role there. And there's things that are just emerging. We are not very good in terms of looking at chemicals, understanding their effects on the immune system and the endocrine and the immune systems are two communication systems and they will communicate with each other the kidneys as well. Kidney function as well. We've not necessarily there's not that much research done on this. And all these diseases don't have one, They're multifactorial. They don't have one cause. And I don't think there's anyone out there that is saying chemicals are causing this or are causing this increase, but they contribute to an overall picture.
I think the example comes with a passive change because, for a very long time, there were arguments saying, listen, this is about what people are eating, not necessarily the, the chemical contaminants in there. And they, they can be seeing animal experiments. They've found that [00:15:00] both high fat diet, and exposure to some chemicals like bisphenol a contributed on their own and then they contributed to a greater effect together. So that's happening and often that, Ultra processed foods will, these will, will be in contact with a lot more chemicals throughout their, throughout their process and their packaging et cetera.
So these things are difficult to differentiate.
Yeah, it sounds really, it's really fascinating, but also really complex that there are just so many, so many possible interactions and it sounds like there are a lot of very critical points in our life where they can have an impact on our health.
Is there a cumulative effect of EDC exposure over time and does this differ between children and adults?
Um, I'd say for children. So I might [00:16:00] unpick what is meant by cumulative. I think there's different ways in which the chemicals themselves may accumulate and therefore the effects may accumulate.
So there are those that sort of not really broken down in the body. That can accumulate the same chemical, can accumulate over time. Part, particularly those that are, that like fat, they're lipophilic. They can accumulate in some tissues. They're not, our bodies don't necessarily get rid of them.
So the concentrations sort of increase. Then there are those that are in widespread use, so we do metabolise them but because we're constantly re-exposed to them, they're always there. And then there's the fact that we exposed to not just one chemical at a time, but we exposed to mixtures of chemicals so they accumulate, or the effects accumulate in that way as well.
And we've talked about in children these critical windows of [00:17:00] exposures. So, theu are times where our bodies are partly sensitive to be being knocked off track a little bit. And it's going to be time sensitive rather than an accumulation. But it's also in, in adults when we have a fully developed working endocrine system if you are constantly being knocked off the normal functioning there, there will be some, yeah, there will be some kind of effect eventually. You can't just keep coming back to the status quo. And in other things I look at, when we look at, ecological resilience or eco social resilience. There's this ball and, and cup kind of picture that we use.
And if you're thinking of an ecosystem, you know, if you. You could have change over times where it's not just about whether the, the ball comes back to to where it [00:18:00] is in the cup every time you knock it back, but you are changing the shape of the cup. And that's the way I think about it. If you are constantly even if you have an established system, but if you've constantly sort of disrupting it.
A little bit, bit by bit. You're probably going to change the shape of that cup and change the way it, it reacts.
Really interesting. Yeah, that's a really helpful way to think about, think about it. We, you've talked a bit about the different kinds of endocrine disruption chemicals and it sounds like there's just so many out there.
Ones that I've heard about in the news, a lot of forever, chemicals, and I've also heard of another group called Persistent Organic Pollutants.
Mm-hmm.
What is the difference between all of these and how do they relate to endocrine disruption chemicals? Are these a group of chemicals that you look at within environmental toxicology?
Yes, we do look at them. So, I think what's been termed the ‘forever chemicals’ [00:19:00] are these perchlorinated compounds. Some of them are POPs so these POPs is Persistent Organic Pollutants this is actually a legal term. In some ways because these are. POPs are listed under a multilateral environmental agreements.
The Stockholm convention, there's about 30 odd chemicals that are listed there, and it's sort of being flagged for being eliminated or phased out. Particularly because, because they are persistent to many of those. If not, most of those have, a bond with halogens. So, then I think it's call them 17 in the periodic table.
They form very strong bonds with carbons that are very hard to break down. That's why they're persistent and that's why they've been used in some of their users have been based on, on that property, particularly for those that are flame retardants, because they will take a little bit[00:20:00] longer to break down if they are being burned, that it sort of slows down the, the fire and some of the allergens of interest, So iodine our body uses particularly for the functioning of, of thyroid hormones. But the other ones are going to be chlorine, bromide, and, and fluoride. The strongest bond being with the latest type of compounds that are days with containing fluoride.
These PFAs are forever chemicals. And there's a lot of perfluorinated chemicals, so only some PFAS will be listed. And there's like big arguments about how do you, how do you define that group? Where's the limit? How many chemicals are in there?
Are there particular POPs or pops that are commonly found in or on plastics, used in healthcare or consumer products?
So, the ones that are POPs should be sort of eliminated. So there's some kind of bans on, on [00:21:00] producing them, but as with any piece of legislation, there's some exemptions and there's some exempted uses. So checking this, I think for, there's a flame retardant that we call deca-BDE. So it's Decabromodiphenyl ether.
That's still allowed in some textiles and some plastics or some, Polyurethane foams. Et cetera. There's Bromooctadecane and polystarins in buildings. But sort of thinking of those that may be used in healthcare, there are, those are specifically used for healthcare in some context so the pesticide DDT.
It's still as is still exempted, it can still be used in some context to control the mosquitoes that sort of transmit malaria. And I think there's another one that's called lindane. I dunno if that's healthcare, but [00:22:00] that that is still allowed in some contra products that are used for controlling headlice as a biocide. But These are probably some of the strictest regulation that you'll get when something gets called a POP, particularly around yeah, phasing them out. And that's, that should be most of the countries sort of agree to do this. So there's no way in which we may be producing them and then exporting them to other parts of the world.
It's really good to hear that there's this kind of strong legislation to protect us and the environment, and not just those in our country, but globally. Mm-hmm. So one thing that I've been reading about is as a doctor, I have prescribed and administered probably thousands of intravenous bags of fluids.
Then recently I saw a statement by a major healthcare product manufacturer stating that IV bags and lines can have up to 40% DEHP within them, and that this can be in a significant exposure to neonates and vulnerable patients. [00:23:00] Obviously, we balance these risks and we administer these fluids and medications because, At that time in the immediate, our patients need them and their health depends on them. But can you tell us a little bit about what DEHP is and what long-term effects substances like DEHP can have on our health?
So DEHP is a, is a plasticizer, so it's they're called additives. But I, when I found out the type of Concentration or, or the amount of DEHP there may be in a plastic. And so additive make it sound like it's like a little bit of something that you are adding when, as you say it's, it can be most of your material… So it's 40% I've seen 10 to 35% depending on how they help make plastic flexible.
So depending on how flexible you want to make your plastic. There'll be more or less of these plasticizers or phthalates. They can have a broad spectrum of effects. So that's the. [00:24:00] The other level of, of complexity with some of these endocrine disruptors, because they're disrupting a system, you kind of get a scatter gun spectrum of possible effects that you would be having.
So some of the things we were mentioning before. They, they might be involved in. So effects on the developing brains have involved phthalates. They can have effects on, on reproduction, particularly male reproduction development of the male reproductive system. But also they also obesogens et cetera.
So there's. We got to a point where it's a little bit more complicated to deal with chemical exposures and, and their effects because the very obvious one that were very specific where you had a strong specific association between one type of chemicals and, and the effect with picked up those long ago.
Those can be many chemicals and they [00:25:00] can all contribute together to to kind of the spectrum of effects. They use in, in medical products. So some of these have been subject to they will kind of look at the risks and benefits because it is a difficult decision to make. And particularly, and if I remember rightly, when they were looking at the use in, Premature babies, et cetera. If, if your tubing is not flexible enough, you will cause pain. You probably know a lot better, better a lot more about this than myself. So that these were the sort of things they are looking at. Interestingly in, in blood bags the DEHP helps preserve the red blood cells from, from what I understand.
So it's having these other effect. And when I was trying to look this up interestingly there is a restriction that's coming in. So they've given in a bit of times, I think by 2030 [00:26:00] DEHP will no longer be used allowed to be used in, in medical devices including blood bag blood bags.
And what this is triggering is, is a lot of research and a lot of search for for alternatives, for things that will work equally well and if we can replace them with safer chemicals that have the same kind of functionality. So it's interesting that they've given that, you know, there's a five year period to to come up with with a solution.
And I think that's yeah, that's an example of how actually regulating can really trigger innovation. Sometimes regulation gets a bad name in terms of really being a barrier to innovation, but actually they can really spur this on because now there is an imperative to do something and we really good at finding things.
So we probably, you know, people will come up with, with alternatives, they will work on this a [00:27:00] lot more intensely than they would have without having that imperative.
Yes. Really good to hear that.
It's important to give it time as well because you don't wanna jump from the fire from the pan into the fire.
And what's happened often and what chemical regulation is tried to get better at is what we call regrettable substitution. So you move from one chemical to, it's like a whack-a-mole game. You move from one chemical, one molecule, it gets regulated and you tweak it a little bit. And you move on to, to the next. I think that's what's happened with Bisphenols to some extent. So now they're trying to be better at regulating groups of chemicals so that you don't, you replace a chemical by something that's genuinely different.
Really interesting. So you touched there briefly on Bisphenol. So I've often seen the words BPA free [00:28:00] on plastics around me and on things in the shops.
In your opinion, does that cover enough or should we be considered, or should more chemicals be considered? You kind of mentioned that Whack-a-Mole and with all these different groups.
When public attention is turned on a, a very specific chemicals, I think there's marketing strategies to exploit that. A lot of it's difficult with BPA a lot of BPA free may contain these other bisphenols that replace BPA.
So, and I think every, every person probably would think, you know yeah, you slightly tweak the molecule. You, it's not BPA, it's BPS or BPF. And you know, you do some research and you find that it pretty much has the same sort of effects. Surprise, surprise. So, no, it doesn't necessarily give a, an overall picture and it's just like looking at one specific chemical at a time.
But I'm also very [00:29:00] yeah, I'm, I'm. It was a very pro regulation. I think it's a bit unfair to put the responsibility to try to avoid or, or navigate avoiding these chemical exposures to the individual, whether they the individual consumer or even the individual clinician. And that these things really need to be, regulated. That's, that's the only way that it kind of really works. And they need to look at that broad picture because someone in the shop, or, or if you are yeah, in clinic or whatever, you can't necessarily make that call. That's, some of that information has to be digested for you beforehand.
And yeah, BPA free, that will help sell more bottles, but that's not necessarily...
Yeah, it's really complex, as you say, as an individual and as a clinician. It's really hard to try and understand. Is there anything that we can look out for? You kind of said that BPA free is a bit of a marketing strategy. Can we trust it or are there other [00:30:00] labels or warnings that we can look out for?
I think a lot of people have been. That are worried about these things. I've moved to stainless steel to more inert materials. It will depend on the situations. Like glass is pretty inert as well, but it breaks and it can be dangerous with yeah.
I've done a fair bit of work looking at what we call food contact materials. So they can be your, your food packaging or it goes beyond that is when your food is being processed, what material it's been in contact with. And what normally tell people is if you can like, try to cook from scratch At home that be a way of cutting down a lot of exposures, but also I don't think it's fair for it to be with the responsibility of the of the individuals.
So it's about maybe making sure that people are informed and, and putting that [00:31:00] consumer pressure or political pressure for something to be done about it. Rather than expecting or the kind of responsibility being shifted to individual people or patients to have, to have to deal with this issue on their own.
It's, it's really helpful to hear that there's regulation, some already in place to protect us, but there's also that push for more so that less of that kind of responsibility and theories on us, and it's really helpful to have those tips, as you've said, on what we can do in the meantime, those simple steps to protect ourselves.
Do we need to try and eliminate EDCs entirely, or is it okay to be exposed to a certain amount of them?
I think it's going to be difficult to, to eliminate them entirely and it will depend on, on situations as well as you are dealing with a situation that's related to healthcare. Sometimes it's about looking at [00:32:00] the balance of risks and, and benefits.
I'm not sure that Chemical regulation, it was particularly, European level, was pushing in the right direction. But at the moment there are other forces that are trying to roll back a lot of these things. Particularly there's something called the chemical omnibus related to to cosmetics and pesticides.
And in the UK with, with Brexit in, in the few years that we've been sort of disconnected from European legislation. It has moved on. It had moved on quite quickly already, so we've, we have fallen behind. So yeah, that's where I think we, we need to, well, I would, if you have to do one thing and say, instead of worrying about it at an individual level, I think putting that public pressure on politicians, on, if you're talking about procurement, it's maybe across your value chain as [00:33:00] well. Is, is as important as the individual actions that you may take. Because if we want these things to be regulated properly, I think that, that, that public pressure, that political pressure needs to t be there and to be maintained.
So they are concepts, just essential uses. I don't think we will do away completely with chemicals in our lives and they have beneficial effects and they've really useful and particularly in a scale they've really helped and have achieved, helped achieve a lot of progress. But there's also uses that we don't necessarily need. I think some of the forever chemicals debates, there must be some uses. I think there are some essential uses in healthcare as well where you wouldn't want to do away with some of the technologies that's been achieved through that. But that doesn't mean I want to have them In a cream, in a cosmetic cream that I'm gonna slap up on my face or anything like that.
So it's, [00:34:00] it is complex. It is maintaining those use that we think are really essential without this being the door for loads of other uses that bring little benefit. I think one of the big differences with the way these everyday chemicals are regulated compared to, to pharmaceuticals is they don't necessarily have to demonstrate a benefit.
Yeah.
Thank you. Really interesting. And yeah, as you say, I often think plastics can be such a great. They are really great material. They've got all these incredible properties. It's just when we use them inappropriately. So I think it's really interesting to hear you say we need to just be focusing on those essential uses and getting rid of them and all those unnecessary things like toiletries and cosmetics where we just don't need these harmful chemicals.
Mm,
we do, and I mean, humans are very, very inventive and innovative. And, and if you, if you create the [00:35:00] They impede us to, to find solutions. We will. So some of the things that are on the radar, at least in the EU is that they want to use digital product passports. And I assume that will, apply to medical devices as well.
So you should have, I dunno how it would work in, in practise, but you should have some kind of QR code where you will find these substances of what we call substances of very high concern and where they may be in your device or your product. So it's about having that information I think that will change things a lot.
The, the other thing, and that's voluntary. Initiative is to really start about the safety of products or materials of chemicals at the design stage. This kind of chemical regulation is often that the last hoop that someone has a brilliant idea, They do everything they need to do and then just before they [00:36:00] can put something on the market, they have these annoying things to do that's related to chemical safety that's not been integrated in the way they design the product in the first place.
So chemical regulation is often a little bit of a party pooper, And that's why it's seen as a barrier to innovation. But actually if you really in, in a very similar way that's been done for pharmaceutical, if you think of their safety at the point that you are designing your chemical, your material or, or your device, I think we will come with clever solution. We, we will come up with clever solutions to some of these problems.
Yeah. Fantastic to hear and really exciting to think that there'll be all these innovations hopefully coming out from amazing people that will help keep us safe. And it's really good to hear about kind of your recommendations. So we should be putting in that pressure on to get this legislation or, regulation to help protect us rather than kind of panicking as individuals, but really helpful to have [00:37:00] those few small kind of little steps you say we can take, like thinking about what we put our food in and how we cook it. So really helpful to have those little tips. Thank you so much for your time today, Dr.Martin. It seemed really great to talk to you and it's been a really wonderful guide through such a complex topic. So thank you.
