Speaker 1: The history of plastic is intimately tied to the history
Speaker 1: of the game of billiards. In the eighteen sixties, the
Speaker 1: billiard's industry had a problem. The game was super popular,
Speaker 1: but it was hard to keep up with the demand
Speaker 1: for high end billiard balls because the material used to
Speaker 1: make the balls was limited. The material was elephant tusks,
Speaker 1: and it took about two tusks to make a complete
Speaker 1: set of balls. A major billiard ball company offered a
Speaker 1: ten thousand dollars reward for anyone who could come up
Speaker 1: with a sturdy alternative. John Wesley Hyatt was inspired by
Speaker 1: this call, and he came up with an alternative to
Speaker 1: tusks that became the first industrial plastic. Now, the initial
Speaker 1: prototypes had the downside that they were highly flammable, and
Speaker 1: there were rumors that they would sometimes explode upon impact
Speaker 1: during a game. Or maybe that's an upside because it
Speaker 1: would make the game a lot more exciting. But anyway,
Speaker 1: today plastics are ubiquitous. They're in our tires, our clothes,
Speaker 1: they line our paper cups, they make disposable medical equipment
Speaker 1: which helps protect us from transmissible diseases, and the microphone
Speaker 1: in computer that I'm using to record this episode have
Speaker 1: plastic in them too. It's kind of hard to imagine
Speaker 1: life without plastic. We're probably all aware that plastic has
Speaker 1: downsides too. We're not really good at disposing of it properly,
Speaker 1: for example, And there's now garbage patches in the ocean,
Speaker 1: which are spots where currents have aggregated the trash we've
Speaker 1: released into the sea. And we've probably all seen images
Speaker 1: of animals like turtles and birds that have died from
Speaker 1: consuming or getting trapped by large pieces of plastic. And
Speaker 1: those are the easy to see problems. In the last
Speaker 1: decade or so, we've become more concerned with the plastics
Speaker 1: that are harder to see, the micro and the nanoplastics.
Speaker 1: These are bits of plastic less than five millimeters in length,
Speaker 1: which is like about the length of an ant, and smaller,
Speaker 1: much smaller. Some of these tiny plastics are made on
Speaker 1: purpose for use in things like cosmetics, and some are
Speaker 1: just the teeny tiny bits of bigger pieces of plastic
Speaker 1: that have broken down over time. These tiny pieces of
Speaker 1: plastic are now found around the globe. Even pristine environments
Speaker 1: that rarely see people will see our plastics because super
Speaker 1: small plastic pieces go airborne, and they move with air
Speaker 1: currents around the world closer to home. We've found very
Speaker 1: small pieces of plastic in human hearts, brains, testicles, and more.
Speaker 1: It's even been found in baby maconium, which is a
Speaker 1: baby's first poop, so it's working its way through a
Speaker 1: fetuses as well. How worried should we be? This is
Speaker 1: an episode of Daniel and Kelly's Extraordinary Universe, So you've
Speaker 1: probably already guessed that the answer is, well, we don't
Speaker 1: really know. We haven't been studying this for very long,
Speaker 1: and as we'll discuss, it's a hard problem to study,
Speaker 1: and it's not feasible or maybe even design mirable to
Speaker 1: stop using plastics entirely. So what do we do about
Speaker 1: microplastics if we decide we should be worried? Welcome to
Speaker 1: Daniel and Kelly's Plastic Universe.
Speaker 2: Hi. I'm Daniel. I'm a particle physicist, and I'm a parent,
Speaker 2: so I always think we should be worried.
Speaker 1: Hello. I'm Kelly Wayne or Smith. I study parasites and space,
Speaker 1: and I have severe anxiety, so I also always worry,
Speaker 1: and actually being a parent made that a little bit worse.
Speaker 2: All right, Well, then my question for you is do
Speaker 2: you think worrying helps? I mean, I know this is
Speaker 2: like culture of worrying. Jewish mom send each other messages
Speaker 2: like start worrying. Now you could probably like hire a
Speaker 2: room full of Jewish mom somewhere, like worry on your behalf?
Speaker 2: Have you know nine dollars an hour or ninety nine?
Speaker 2: I don't know think that worrying helps. Does it make
Speaker 2: us think deeply about all the possible issues? Does it
Speaker 2: make us better scientists? What do you think?
Speaker 1: I think?
Speaker 2: What's the upside of worrying?
Speaker 1: It depends. I think so. I think Zach doesn't worry enough.
Speaker 1: And so there have been a couple of times where
Speaker 1: I've felt like I've had to step in to get
Speaker 1: the worrying level up to the right amount so that
Speaker 1: we could take care of some problems that needed to
Speaker 1: get taken care of.
Speaker 2: Was that when your stove was on fire recently? For example?
Speaker 1: Uh no, I I actually when I opened up the
Speaker 1: stove and I looked inside and I saw the fire,
Speaker 1: which was not my food, thank you very much, It
Speaker 1: was something else. My first thought was I should call Zach,
Speaker 1: and my second thought was what would he do? I
Speaker 1: don't need to call Zach. And then it turned out
Speaker 1: that Zach's brother had given me a fire extinguisher, So
Speaker 1: who I needed was Zack's brother. Thank you, Marty, and
Speaker 1: I pulled out the fire extinguisher. Everything was okay, I
Speaker 1: need to change the heat element or whatever. But I
Speaker 1: think you need to worry a little, but you need
Speaker 1: to not overdo it. And I massively overdo it. Zach
Speaker 1: underdoes it, and then I think we average are worrying
Speaker 1: and we get the right amount of stuff done. But
Speaker 1: what do you think, Well.
Speaker 2: I have this friend who's a neuroscientist who thinks that
Speaker 2: worrying is what makes us better scientists, because you like
Speaker 2: wake up in the midlight you're like, wait a second,
Speaker 2: what if this part of that paper is wrong? What
Speaker 2: if blah blah blah blah blah, How would I know
Speaker 2: for sure? And then you come up with another test
Speaker 2: to verify that, And so it really helps make your
Speaker 2: science bulletproof because you sort of put yourself in the
Speaker 2: mind the reviewer and ask all the critical questions, and
Speaker 2: you worry about being embarrassed in front of your colleagues
Speaker 2: when your results are shown to be an artifact. So
Speaker 2: I think that it is helpful in that sense, and
Speaker 2: it also helps you prepare for eventualities. Like the reason
Speaker 2: I buy insurance is because I worry about stuff, right,
Speaker 2: But I agree that it can go too far. It
Speaker 2: can be unproductive for sure. But you know, I think
Speaker 2: on this podcast we aim for just the right level
Speaker 2: of worrying. We aim to educate you enough to make
Speaker 2: knowledgeable choices about your life.
Speaker 1: Right, Yes, that's right, that's exactly right.
Speaker 2: And so you hear all about disgusting parasites you will
Speaker 2: probably never get and don't have to worry about. But
Speaker 2: now you know enough not to go swimming with snails
Speaker 2: in Venezuela or whatever it was.
Speaker 1: Well, and you know what questions to ask your doctor
Speaker 1: when you go see here you go, Yeah, something like that.
Speaker 1: That's our goal.
Speaker 2: That comes from a person who has repeatedly gone to
Speaker 2: the doctor convinced he had toe cancer.
Speaker 1: Toe cancer in particular. Is there something weird about your
Speaker 1: toes that that makes you think they're cancer?
Speaker 2: Is No, I am just a hypochondriac and am capable
Speaker 2: of convincing myself that's some weird thing. It's probably cancer
Speaker 2: and a better of the doctor. And I'm the kind
Speaker 2: of guy who shows up the doctor without a list.
Speaker 2: Here's seven reasons why I'm dying. Let's go through them.
Speaker 1: Ah.
Speaker 2: And you know, a good doctor is the one that,
Speaker 2: like knowledgeably but patiently walks you through the reasons why
Speaker 2: you're not dying today.
Speaker 3: That's right.
Speaker 1: So I came. I came with my own list for
Speaker 1: the same thing for the doctor. And after I went
Speaker 1: through the list, the doctor said, can I ask you
Speaker 1: some questions? Can I give you a survey for anxiety?
Speaker 1: And we discovered Kelly doesn't have cancer. Kelly has severe anxiety.
Speaker 1: So thank you to that doctor for listening to what
Speaker 1: I wasn't saying.
Speaker 2: And so today we're actually doing an episode about something
Speaker 2: I've been wondering about whether we need to be worried about,
Speaker 2: but I wasn't knowledgeable enough about it to know whether
Speaker 2: worrying was justified or just my anxiety.
Speaker 1: And you know what, it's nice to get clear answers,
Speaker 1: but you're not getting that today. Daniel also, sorry, but at.
Speaker 2: Least I'm going to be brought up to the forefront
Speaker 2: of current.
Speaker 1: Knowledge, right, that's right, that's right.
Speaker 2: You will me so I won't have to be worried
Speaker 2: that I don't know enough to worry. So there you go.
Speaker 1: All right, there you go. Well, so let's start by
Speaker 1: seeing what the general public thinks of this question, or
Speaker 1: at least what the extraordinaries, who are probably not a
Speaker 1: random subset of the general public. Let's see what our
Speaker 1: extraordinaries think. So I asked, should we be worried about
Speaker 1: microplastics or why not?
Speaker 4: Probably not. I've seen articles that microplastics are everywhere and
Speaker 4: they're going to ruin our health in the environment, but
Speaker 4: I've never seen them give irrelevant context, such as what
Speaker 4: the biological effects are. I'm open to learning more, but
Speaker 4: in the meantime, I'm not too worried about it, and
Speaker 4: I'll continue to worry instead about climate change and my
Speaker 4: own diet.
Speaker 5: I certainly believe that we should be worried about microplastics.
Speaker 5: First of all, there is a coating of plastic around
Speaker 5: the world so thick that anthropologists are considering naming our
Speaker 5: current epoch of the plastic scene because it'll form a
Speaker 5: permanent layer that doesn't even begin to show all the
Speaker 5: potential harmful effects of the microplastics.
Speaker 2: Our immune system simply has not evolved to remove plastics
Speaker 2: from our bodies, and the more they accumulate, then the
Speaker 2: more we can expect trouble.
Speaker 3: Microplastics have been discovered all over the globe, I believe
Speaker 3: in Antarctica. We don't know absolutely sure the link and
Speaker 3: mechanism to problems, but it can't be good.
Speaker 6: In about seventy five years, we went from there being
Speaker 6: none to now being so pervasive that they can be
Speaker 6: found in the deepest depths of the ocean and even
Speaker 6: in our brains. I would love to know what these
Speaker 6: materials can be doing to our health and the rest
Speaker 6: of the ecosystem, so we can support policies that limit
Speaker 6: its production and perhaps even help clean it up.
Speaker 7: Yes, I do think we should be worried about microplastics.
Speaker 7: We don't know how our bodies, animals, and the environment
Speaker 7: are affected by these things, and we should investigate more.
Speaker 2: All right, So a lot of people out there feel
Speaker 2: like there might be something to worry about. At least,
Speaker 2: it's somewhat alarming that there's plastics everywhere. We don't really
Speaker 2: understand what they might do or how they might interfere
Speaker 2: with the function of this incredibly complex Goldberg machine we
Speaker 2: call our bodies.
Speaker 1: Yeah, that's right, And I thought it was interesting. One
Speaker 1: of our listeners mentioned that to sometimes suggest we could
Speaker 1: call this era the plastic scene, because if you geologically
Speaker 1: dig through, you can see a layer where plastic has
Speaker 1: essentially been accumulating as we've made it go like airborne
Speaker 1: and all over the planet. And so I feel like,
Speaker 1: you know, if you look at human impacts first, you'll
Speaker 1: see like a layer that's a bit radioactive from all
Speaker 1: of our nuclear tests, and then you'll see a plastic layer.
Speaker 1: And you know, we've done a lot of beautiful things,
Speaker 1: but I don't feel like geology is telling a beautiful story.
Speaker 2: Wow, what a record we are leaving.
Speaker 1: Huh, that's right, that's right. But we do a lot
Speaker 1: of amazing things with plastics, right, And so one of
Speaker 1: the things that kind of frustrated me when I was
Speaker 1: you know, I tried to see how other people have
Speaker 1: covered this topic, and there's a lot of people being like, oh, plastics,
Speaker 1: they're horrible, and like, I get it. I get it.
Speaker 1: I'm an ecologist. I worry about the environment. I worry
Speaker 1: about the impacts on animals. I worry about the impacts
Speaker 1: on us, But plastics really make our lives a lot better, right, Like,
Speaker 1: I think you need to keep in mind the trade.
Speaker 2: Offs here, give me a top five reasons why plastics
Speaker 2: are good for humanity?
Speaker 1: Well, I mean, so we've got like all of the
Speaker 1: disposable plastic medical equipment that helps make sure that we
Speaker 1: don't transmit diseases to each other. That's pretty great. Most
Speaker 1: of our clothes now, even clothes that are made of
Speaker 1: natural fibers quote unquote, have some plasticky stuff in them.
Speaker 1: And you know, I think making clothing more affordable and
Speaker 1: making it so that everybody can afford to where things
Speaker 1: that make them feel nice is huge and great. And
Speaker 1: in general, I don't know that I'm going to go
Speaker 1: for all five because I don't know that people really
Speaker 1: care about Kelly's top five things. But in general, I
Speaker 1: think there's a lot of things that are now within
Speaker 1: the price range of the average American that wouldn't be
Speaker 1: if we had to use quote unquote natural substances. And
Speaker 1: natural substances aren't necessarily always better for the environment. So,
Speaker 1: for example, we started this episode with the story about
Speaker 1: wanting to find a different material to make billiard balls
Speaker 1: out of because we were using elephant tusks. Oh no,
Speaker 1: so everything's a trade off. You know, if we were
Speaker 1: to get all of our products from nature. That would
Speaker 1: be pretty damaging to the environment also, and so I
Speaker 1: don't know, I'm Kelly. So the message here is it's complicated.
Speaker 1: It depends you need to look at it from a
Speaker 1: number of different angles.
Speaker 2: Well, so tell me how long have we had plastic
Speaker 2: I imagine it's something that came about in the space age,
Speaker 2: like the sixties seventies, you know, Dow chemicals invented or something.
Speaker 2: I'm pretty fuzzy on the history here. Educate me.
Speaker 1: Well, So that billiard ball example, that was one of
Speaker 1: the first examples of someone making a plastic y substance.
Speaker 1: It was celluloid and it was a hard substance so
Speaker 1: that you could bounce billiard balls off of each other
Speaker 1: without having them like sort of dent and bend in
Speaker 1: ways that would impact how they moved. They were slightly flammable,
Speaker 1: which I mentioned in the introduction, and so if they
Speaker 1: spang together sometimes they would set on fire, which would
Speaker 1: actually make me watch a game of pool. And so,
Speaker 1: but large scale production didn't really start until the nineteen fifties.
Speaker 1: Around the nineteen fifties the nineteen sixties, like single use
Speaker 1: you know, plastic spoons, single use plastic everything really became
Speaker 1: fashionable as a way to make our lives easier, and
Speaker 1: they were really they were much less expensive than a
Speaker 1: bunch of the other stuff. And so since the nineteen fifties,
Speaker 1: the amount of plastic in our lives has been increasing
Speaker 1: at a tremendous rate. And that's the big plastic stuff.
Speaker 2: And so help me understand why, Like, if we knew
Speaker 2: how to make this stuff for one hundred years, why
Speaker 2: do we only really begin making it in large volume
Speaker 2: in the fifties. Was this after like post World War
Speaker 2: two industrialization or something else.
Speaker 1: I didn't look too much into the history of plastics,
Speaker 1: but my sense is that it did take a while
Speaker 1: to figure out the chemical processes. And so, you know,
Speaker 1: plastics as a category, like encompasses loads of different kinds
Speaker 1: of plastics that are good for a lot of different purposes.
Speaker 1: And so I think it took us a while to
Speaker 1: figure out how to make different kinds of plastics, what
Speaker 1: they're good for, how to industrially scale up so that
Speaker 1: we could, you know, use them for lots of different stuff.
Speaker 1: How do you make injection molds for this kind of stuff.
Speaker 1: I think all of that just took a while.
Speaker 2: All right, And so we're talking about plastic spoons and
Speaker 2: plastic medical equipment. I know Katrina uses it for her diabetes,
Speaker 2: she has these tubes, et cetera. But nobody's manufact cturing microplastics.
Speaker 2: What are microplastics exactly?
Speaker 1: Well, people are manufacturing microplastics as I understand it, the
Speaker 1: bulk of the plastics. So the bulk of the plastics is,
Speaker 1: you know, you get a plastic bag, you get a
Speaker 1: shirt with some plastic in it, and it ends up
Speaker 1: either in a landfill or it ends up in the ocean,
Speaker 1: and over time it breaks down. It could be because
Speaker 1: UV radiation is breaking it down into pieces. It could
Speaker 1: be because there are just fibers on your shirt that
Speaker 1: go airboard and they end up on the floor in
Speaker 1: your carpet in your home. So they come from big
Speaker 1: plastic breaking down, but they do also come from purposefully
Speaker 1: making small pieces of plastic. So for a while, it
Speaker 1: was fashionable to have microbeads in like exfoliation stuff, so
Speaker 1: like cosmetic stuff for like washing your face to help
Speaker 1: like move dead skin cells off. We now have rules
Speaker 1: in both the US and Europe against that kind of stuff,
Speaker 1: but you can still end up with microplastics in I
Speaker 1: think you can have them like in moisturizers. They almost
Speaker 1: act like ball bearings, just making it so that things
Speaker 1: go on a little bit smoother. But let's do some
Speaker 1: definitions here. Microplastics are defined as things that are five
Speaker 1: millimeters in size or less. That's true. Big, Yeah, that
Speaker 1: is pretty big. That's like an ant, right, that's something
Speaker 1: you could see. So anything five millimeters in size or
Speaker 1: less is a microplastic. But we also have a category
Speaker 1: called nanoplastics, and these are one micrometer in size or less,
Speaker 1: So these are probably not something you're likely to see.
Speaker 2: I hold on, microplastics are millimeter sized, nanoplastics are micrometer sized.
Speaker 2: Why don't they line up the name with the size, Like,
Speaker 2: why don't nanoplastics be nanometer and microplastics be micrometer? Wouldn't
Speaker 2: that make sense?
Speaker 1: That would make sense. And it's a bit ironic that
Speaker 1: the physicist is complaining about naming. But I'm not gonna say.
Speaker 2: You know what they say, Every accusation is a confession.
Speaker 1: That's right, that's right. I don't know who's to blame
Speaker 1: for this naming system, but yes, you're right, it's not intuitive.
Speaker 2: Pico plastics are one nanometer in size. That's all right.
Speaker 2: So we have microplastics, which are actually kind of big nanoplastics,
Speaker 2: which is super duper small. But how much of this
Speaker 2: really is around?
Speaker 1: First, I want to say, it's really hard to estimate.
Speaker 1: And while I was reading, the more recent papers are
Speaker 1: estimating more and more and more. And that's because we
Speaker 1: have better and better techniques for identifying smaller and smaller
Speaker 1: pieces of nanoplastic. So it's pretty easy, like by eye
Speaker 1: to count how many pieces of plastic fibers that are
Speaker 1: five millimeters long are in a water sample, for example,
Speaker 1: but looking at objects that are one micrometer or less
Speaker 1: is much harder. But there's an estimate that fifty one
Speaker 1: trillion microplastic particles are floating in our ocean. Trillion, trillion, trillion,
Speaker 1: I said, trillion, Yeah, oh my gosh. I read this
Speaker 1: book called A Poison Like No Other by Matt Simon,
Speaker 1: and it's all about microplastics. And he talks about how
Speaker 1: microplastics have been found in invertebrates in the Marianna ste
Speaker 1: Trench in the most remote mountainous regions you can go to,
Speaker 1: and like this has just permeated our entire world. So
Speaker 1: you know, when we drive down the road, we kick
Speaker 1: plastics off of our tires. Some of those go airborne.
Speaker 1: They take air currents, you know, to the ocean or
Speaker 1: across the ocean. Anywhere you go and sample, there's a
Speaker 1: really good chance that you are going to find a microplastic.
Speaker 1: I feel like I should at a caveat. I do
Speaker 1: feel like that book over sells what we know about
Speaker 1: the risks a bit. But if you are looking to
Speaker 1: be scared and you're looking to understand where all the
Speaker 1: microplastics are and how much of them are out there,
Speaker 1: that book is encyclopedic in its laying out of where
Speaker 1: we find these things and how they might be hurting us.
Speaker 2: I'm still having my mind blown by the number. Fifty
Speaker 2: one trillion. Yeah, more microplastics than there are stars in
Speaker 2: the galaxy. Like if Elon Musk wanted to buy all
Speaker 2: the microplastics for a penny each, he couldn't afford it.
Speaker 2: It's just hard to grapple with that number.
Speaker 1: It is, and again you should consider that number to
Speaker 1: have huge error bars. But for example, like there was
Speaker 1: a study looking at how many pieces of microplastics are
Speaker 1: in a bottle of water, and you you know, you
Speaker 1: think when you get a bottle of water, you're getting
Speaker 1: something that's nice and clean. Some bottles of water had
Speaker 1: essentially no pieces of plastic in a liter of water.
Speaker 1: Others had up to ten thousand particles of plastic in
Speaker 1: a liter of water.
Speaker 2: Oh boy, they should list on the ingredients including ten
Speaker 2: thousand part plastic.
Speaker 1: That's right, well, and a lot of it probably depends
Speaker 1: on like, you know, how were those water bottles stored.
Speaker 1: Did they get like left out in the sun for
Speaker 1: a few hours, because that breaks it down. Now plastics
Speaker 1: are starting to come out, and part of why the
Speaker 1: numbers get so big when you're talking about how many
Speaker 1: pieces of microplastics are in the environment is that they
Speaker 1: don't break down really well. So a big plastic bag
Speaker 1: will break down into much smaller component parts, but after
Speaker 1: that they don't break down the way something biological would.
Speaker 1: So when you've got biological stuff out there, you have
Speaker 1: decomposers that go and they eat it and they turn
Speaker 1: it into other stuff. There are some plastic war is
Speaker 1: that we're discovering, some like bacteria that can break down plastic,
Speaker 1: but in general, plastic is a thing that wasn't really
Speaker 1: in our environment in super high quantities in the past,
Speaker 1: so evolution doesn't necessarily have a way to break it down.
Speaker 1: Nature doesn't really have a way to break it down,
Speaker 1: and so they tend to accumulate and they break down
Speaker 1: to like some point where they're very small, and then
Speaker 1: often they appear to stop breaking down and then they
Speaker 1: just accumulate in these small sizes.
Speaker 2: So that's the thing I'm trying to wrap my head
Speaker 2: around is that plastic feels really stable, and you know,
Speaker 2: if you have a coke bottle, you expect it's still
Speaker 2: going to be there in one hundred years or a
Speaker 2: thousand years or whatever. So why do they break down
Speaker 2: at all? Like why do macroplastics turn into microplastics and
Speaker 2: then stop breaking down. I would expect they're either stable
Speaker 2: and a coke bottle is going to be here in
Speaker 2: a million years, or it's going to break down into
Speaker 2: like you know, atoplastics or whatever. The smallest fundamental bit
Speaker 2: of plastic is why do they sort of stop breaking
Speaker 2: down at the microplastic level.
Speaker 1: Well, I feel like that's a chemistry question, So I'm
Speaker 1: a little angry, but I'm kidding, But I think what's
Speaker 1: happening is that, like, you know, if you've got and
Speaker 1: I am joking, but you've got like a big piece
Speaker 1: of plastic.
Speaker 2: I just like how you said, I'm angry, but you
Speaker 2: said it with a smile.
Speaker 1: I'm hard to read too, so so you know, So
Speaker 1: imagine you've got like a plastic bag floating on the
Speaker 1: surface of the ocean. It's getting hit by UV radiation
Speaker 1: and that's starting to like break some of the bonds
Speaker 1: and break it into small parts. Those tiny pieces eventually
Speaker 1: get so small that they sort of break away from
Speaker 1: the rest of the bag and they start to sink.
Speaker 1: And as they sink, they sort of end up out
Speaker 1: of the reach of UV radiation, and they end up
Speaker 1: in the sediment, or they can end up in the soil,
Speaker 1: or they end up in the gut of something else.
Speaker 1: And in some cases they probably do keep breaking down.
Speaker 1: Like it's possible that our stomach acid breaks them down
Speaker 1: a little bit. But I think in general plastics, part
Speaker 1: of why they're so useful is because they are sturdy,
Speaker 1: and it takes a lot to break them down. And
Speaker 1: so maybe in a million years, of five millimeter fiber
Speaker 1: plastic piece will disintegrate into its like atomic pieces. But
Speaker 1: it's going to take a while.
Speaker 2: I see. I'm always amazed at the power of UV radiation.
Speaker 2: You know, in my house, if you burn something on
Speaker 2: a pan so you can't scrub it clean, you just
Speaker 2: put it outside for like a week, oh and the
Speaker 2: sun will break it up. It's amazing what UV radiation
Speaker 2: will do. Thank you, Southern California.
Speaker 1: Wait, wait, what is your Okay, what does your backyard
Speaker 1: look like? And how many animals have you attracted by
Speaker 1: doing that? Because I live in a place where animals
Speaker 1: want to be and they'd be licking those plates and
Speaker 1: it would be gross.
Speaker 2: That's fine, that's helpful. You know, some squirrel wants to
Speaker 2: use their you know, long teeth on that thing scrape
Speaker 2: some of that burnt oatmeal off the pan, like, please
Speaker 2: help us out.
Speaker 1: Man, all right, all right, some rabbit raccoon wants to Okay.
Speaker 2: All right, So we have plastics everywhere? How long has
Speaker 2: this sort of been something we've known about, Like plastics
Speaker 2: came about in large quantities like fifty seventy years ago.
Speaker 2: Was it very soon after that that we discovered that
Speaker 2: they were everywhere?
Speaker 1: I mean, I think when plastics started to go mainstream.
Speaker 1: It was, you know, easy to say plastics rolling down
Speaker 1: the street on a windy day or something like. I
Speaker 1: think we've been aware of macroplastics as as a problem
Speaker 1: for a long time. We're not very good at disposing
Speaker 1: of them. They tend to end up in the oceans,
Speaker 1: they tend to end up in animals. So we've known
Speaker 1: that's been a problem for a while. And it probably
Speaker 1: didn't surprise anyone when we first started talking about the
Speaker 1: fact that it breaks down into tiny pieces. But the
Speaker 1: first time of tension was really brought to this issue
Speaker 1: was when a marine ecologist named Richard Thompson wrote a
Speaker 1: paper about how he was collecting samples of sediment from
Speaker 1: beaches and estuaries and the subtitle zone in the United Kingdom,
Speaker 1: and he found microplastics in all of those places. And
Speaker 1: he looked at plankton samples, so these are like tiny
Speaker 1: little samples from the water column. And he looked at
Speaker 1: samples from the nineteen sixties and then at various dates
Speaker 1: getting closer to the present, and he found microplastics back
Speaker 1: from the nineteen sixties. But he also found that they
Speaker 1: were increasing over time and that even you could find
Speaker 1: them inside of the bodies of little invertebrates that live
Speaker 1: in the world, and so he noted that we don't
Speaker 1: know the environmental consequences of having this stuff in the water,
Speaker 1: but it's in the water. This problem is getting worse,
Speaker 1: but it still took about a decade before people started
Speaker 1: really digging in and particularly thinking about the impacts on
Speaker 1: human health.
Speaker 2: I love this example of digging through past samples collected
Speaker 2: for completely separate reasons and finding evidence or answers to
Speaker 2: a question you have later on. This is why you
Speaker 2: should always keep all of your samples and all of
Speaker 2: your notes, because who knows how it's going to be
Speaker 2: useful later. This is incredible. I love that.
Speaker 1: This is why museums are so important, because they do
Speaker 1: they keep those samples for you, and they're in a
Speaker 1: location where anybody can request them. So somebody, and you know, Peru,
Speaker 1: can think of a question that requires American water samples
Speaker 1: from the nineteen sixties or something, and if a museum
Speaker 1: has them, they can get those data. So anyway, yay
Speaker 1: for archiving, material behavior.
Speaker 2: Record keeping exactly all right. So it sort of came
Speaker 2: to the fore in the early two thousands, and then
Speaker 2: has the field sort of exploded in research.
Speaker 1: Yeah, the last ten to fifteen years, we've become a
Speaker 1: lot more interested in what it's doing in freshwater systems,
Speaker 1: what it's doing in oceans, what it's doing in our bodies.
Speaker 1: And let's take a break, and when we get back
Speaker 1: from the break, we'll start digging into that stuff. All right,
Speaker 1: So we have already established that microplastics are like everywhere,
Speaker 1: they're kind of unavoidable, and so let's start digging into
Speaker 1: you know, whether or not we need to worry about that.
Speaker 1: So one thing that you maybe need to worry about
Speaker 1: a little bit is that they bioaccumulate. So you might
Speaker 1: have heard this word from you know, Rachel Carson's book
Speaker 1: Silent Spring about DDT and how as you move up
Speaker 1: the food chain you get more and more concentrated levels
Speaker 1: of the chemicals. And so an example for microplastics is
Speaker 1: that there was a study looking at the soil in
Speaker 1: Mexico and they found that microplastics were a bit less
Speaker 1: than one particle typically in each gram, But if you
Speaker 1: pulled an earthworm out per gram of earthworm, you would
Speaker 1: find almost fifteen particles. So the earthworms were going through
Speaker 1: the soil and as they would ingest a piece of microplastic,
Speaker 1: it was like staying in them. And then they looked
Speaker 1: at chickens that were eating the earthworms, and there were
Speaker 1: one hundred and thirty particles per gram of chicken feces
Speaker 1: because you know, chickens were eating those. And so as
Speaker 1: you go up the food chain for the same like mass,
Speaker 1: you're finding more and more of these particles.
Speaker 2: So why do the earthworms accumulate them? Is it because
Speaker 2: they get filtered out of the soil and they stay
Speaker 2: in the earthworms Like there's something inside the earthworm that's
Speaker 2: like accumulating these things.
Speaker 1: So if you were to take a snapshot of what's
Speaker 1: inside of that earthworm, over like a year of an
Speaker 1: earthworm's life, and I don't know how long earth works live,
Speaker 1: it might not be a year, but like there might
Speaker 1: be a lot of particles that they ingested but they
Speaker 1: pooped out. But because they're going through so much soil,
Speaker 1: if you take a snapshot, they might have about fifteen
Speaker 1: particles per gram of earthworm because they're just moving through
Speaker 1: tons of soil and just sort of accumulating it as
Speaker 1: they go.
Speaker 2: But in order to accumulate it, they have to eat
Speaker 2: more than they poop, so they preferentially don't poop out microplastics, right,
Speaker 2: Otherwise they would have the same density as the soil.
Speaker 2: Like if you just pass a tube through the soil,
Speaker 2: it's going to have exactly the same density as the
Speaker 2: soil unless there's some filter in there that's like accumulating
Speaker 2: the microplastics or preferentially not pooping them out.
Speaker 3: Right.
Speaker 1: Yep, Yeah, that's a great point. You're right, they're accumulating them.
Speaker 1: They might poop some of them out, but in general
Speaker 1: they tend to be accumulating them.
Speaker 2: Yeah. Interesting, And so then the chickens eat those and
Speaker 2: then it gets more concentrated, and eventually when you're eating chicken,
Speaker 2: it's like half plastic.
Speaker 1: Yeah, not necessarily half plastic, but there's a fair bit
Speaker 1: of plastic in there. But one thing that's important in
Speaker 1: mind is that not all plastic matters the same from
Speaker 1: a standpoint of ingesting it. So you can get plastics
Speaker 1: in your body either by inhaling it because a lot
Speaker 1: of it goes airborne, or by ingesting it, and our
Speaker 1: bodies will defecate and urinate out a lot of the
Speaker 1: plastics that we consume, and if you breathe it in
Speaker 1: are what is it called our mucociliary elevator or something
Speaker 1: basically like we will like hawk it up. And actually
Speaker 1: maybe Matt wants to remove that sound effect.
Speaker 2: I don't think no, I think you should keep that.
Speaker 2: And I just wish that the audience could see the
Speaker 2: face you made.
Speaker 1: I was pretty expressive there. But so you know, you
Speaker 1: cough it up and then you can spit it out
Speaker 1: or swallow it and then it'll end up in your
Speaker 1: feces and anyway, all very gross. But our body has
Speaker 1: ways of getting rid of a lot of this stuff.
Speaker 1: But if you've got nanoplastics that are small enough, they
Speaker 1: can pass across our alveoli, which is a point in
Speaker 1: our lungs where our lungs are sort of in facing
Speaker 1: with our blood, and they can get into our bloodstream,
Speaker 1: or sometimes they can move across our gut into the
Speaker 1: rest of the body. So very small pieces can end
Speaker 1: up in other parts of the body where they're not
Speaker 1: going to get removed, or they're much less likely to
Speaker 1: get removed.
Speaker 2: And I've heard it said that we eat like a
Speaker 2: credit cards worth or a bottle cap worth of plastics
Speaker 2: every year or every week or whatever. Is that true,
Speaker 2: or is that people overworrying.
Speaker 1: There was a study that came up with that figure
Speaker 1: and that went like global, just like microplastics, it ended
Speaker 1: up everywhere. But there was another study that looked at
Speaker 1: the numbers a little more critically and they ended up
Speaker 1: deciding something like you would require twenty three thousand years
Speaker 1: or something like that to acquire the amount of plastic
Speaker 1: that that paper was estimating. And so that I think
Speaker 1: what most of us have heard about plastic getting in
Speaker 1: our body is pretty overblown. But that said, they have
Speaker 1: found plastic in human brains. So this was they did autopsies,
Speaker 1: so somebody had already paid away and they looked through
Speaker 1: the brain to look for plastics and they found it.
Speaker 1: Plastics have been found in plaques in our arteries, so
Speaker 1: when your arteries are getting clogged, there's some little pieces
Speaker 1: of plastic in there.
Speaker 2: Two.
Speaker 1: It has been found in testicles, kidneys, livers, like anywhere
Speaker 1: you can imagine, maybe not wanting plastic to be, plastic
Speaker 1: is there. And we found plastic in maconium. Daniel, do
Speaker 1: you remember, I mean I probably said it wrong, let's
Speaker 1: just be clear, but do you remember what maconium is?
Speaker 1: This is a word I only needed to know the
Speaker 1: definition of once or twice in my life.
Speaker 2: Oh, it sounds familiar. It sounds like mucus. Is it
Speaker 2: something gross inside the body?
Speaker 1: It's your baby's first poop?
Speaker 2: Oh, of course, yes, of course, mconium. I remember that.
Speaker 2: Now it's weird looking.
Speaker 1: Yeah, yeah, yes, it's weird looking, and it has plastic
Speaker 1: in it, and so that means it's probably microplastics or nanoplastics.
Speaker 1: Probably nanoplastics are passing from mom to the fetus, and
Speaker 1: the fetus is already, you know, defecating them out pretty soon.
Speaker 1: So we start our life with these microplastics with us.
Speaker 2: And we talked recently about water filtration systems and these
Speaker 2: amazing processes that clean up our water. Are microplastics too
Speaker 2: small to be filtered out?
Speaker 1: No?
Speaker 3: Not so.
Speaker 1: About ninety five percent of the microplastics that go into
Speaker 1: the wastewater treatment plant are removed through the various processes.
Speaker 1: There's a lot of microfibers that go to wastewater treatment
Speaker 1: plants because a bunch of the wastewater that goes to
Speaker 1: those treatment plants is from when we wash our laundry
Speaker 1: or from like our shampoos and body washes. And stuff,
Speaker 1: and our clothes every time we wash them are shedding
Speaker 1: loads of microplastics, and so lots of stuff gets to
Speaker 1: the wastewater treatment plants. About ninety five percent of it
Speaker 1: gets removed. Sometimes the sludge that gets collected at some
Speaker 1: of these plants will get used for other purposes, like
Speaker 1: as a fertilizer, and in that case the microplastics could
Speaker 1: get back into the environment. But if they're just put
Speaker 1: in a landfill, they're probably going to be fine. But
Speaker 1: a lot of them do still get through these wastewater
Speaker 1: treatment plants, and there were some data from twenty fourteen
Speaker 1: to twenty sixteen that estimated that something like eight to
Speaker 1: thirteen billion pieces of microbeads were being released from treatment
Speaker 1: plants into freshwater systems every day. And we're trying to
Speaker 1: use fewer microbeads, but there's still a bunch of these
Speaker 1: getting into our freshwater systems. But they also get into
Speaker 1: freshwater systems or our oceans through other routes. For example,
Speaker 1: a huge source of plastic is our tires, and so
Speaker 1: when we drive, we're wearing some of the plastic off
Speaker 1: of those tires, and that ends up either in the
Speaker 1: air or sometimes it ends up on the side of
Speaker 1: the road, and then the next time it rains, it
Speaker 1: takes those little pieces of plastic into our rivers and
Speaker 1: our lakes, and then in some cases it brings it
Speaker 1: to our oceans. And so yeah, those are some major
Speaker 1: sources of plastic into our aquatic systems.
Speaker 2: And so it's everywhere, and we found in our bodies,
Speaker 2: including our brains and all the other important bits. Why
Speaker 2: is this an issue or is it an issue or
Speaker 2: why might it be an issue for our health?
Speaker 1: Yeah, so we're not super clear on it. First all,
Speaker 1: I want to say that we've done some experiments on fish,
Speaker 1: and the fish seem to get kind of messed up.
Speaker 1: So fish end up, you know, they eat the little
Speaker 1: invertebrates that eat the microplastics, and then they accumulate it
Speaker 1: in their own body. And we found that microplastics can
Speaker 1: mess with things like how the fish move, It can
Speaker 1: damage their intestines. I think in some cases we found
Speaker 1: that it reduces their growth, and it seems to reduce
Speaker 1: their growth because it essentially like takes up space in
Speaker 1: their gut and they like feel like they've eaten, but
Speaker 1: they haven't eaten anything that's nutritious and so you know,
Speaker 1: they lose weight and that can impact their reproduction and
Speaker 1: stuff like that. So we know that there are some
Speaker 1: examples where it's been a problem in fish, but fish
Speaker 1: are swimming in this environment with loads of microplastics, so
Speaker 1: that might not tell us what we need to know
Speaker 1: about people. So here are some of the top issues
Speaker 1: that we worry about for microplastics. One of the main
Speaker 1: issues that we worry about is that these microplastics tend
Speaker 1: to to attract and stick to other stuff in the environment. So,
Speaker 1: for example, they stick to heavy metals PCBs, which are
Speaker 1: polychlorinated by phenols and some other kinds of toxic material,
Speaker 1: and they get what's called sorbed by the plastic.
Speaker 2: Absorbed, not absorbed, just sorbed.
Speaker 1: I think it's sorbed.
Speaker 2: Is that what the kids are saying these days?
Speaker 1: Wow, that's what the science kids are saying these days.
Speaker 1: Very generous to call us kids. But so they pick
Speaker 1: up these toxic compounds and then when they get into
Speaker 1: your body, they could release those toxic compounds. And so
Speaker 1: while a piece of plastic on its own might not
Speaker 1: cause a problem, if it's bringing, for example, mercury into
Speaker 1: your body and then depositing the mercury. The mercury could
Speaker 1: be the problem. Does that make sense?
Speaker 2: Yeah, absolutely it does.
Speaker 3: Yeah.
Speaker 1: Other things that tend to stick to these fibers include bacteria,
Speaker 1: and there's some concern that the way bacteria aggregate, they
Speaker 1: form like biofilms where maybe they could be sharing like
Speaker 1: antibiotic resistant genes or something. This sounded a little bit
Speaker 1: more speculative from what I could tell. But bacteria stick
Speaker 1: to them, and so do viruses, and so these pieces
Speaker 1: of plastic could be ways that bacteria and virus make
Speaker 1: it into your body.
Speaker 2: So basically they're dirty, they're not just weird and artificial
Speaker 2: and everywhere they're dirty.
Speaker 1: They are. But this also contributes to why they're so
Speaker 1: hard to study, right, because whether or not plastic is
Speaker 1: bad for you is going to depend on what the
Speaker 1: plastics saw before it went to you. So like the
Speaker 1: same kind of plastic and an environment with no mercury
Speaker 1: might do nothing, but the same kind of plastic in
Speaker 1: an environment where it can pick up mercury and then
Speaker 1: get to you could cause a lot of trouble.
Speaker 2: Yeah, exactly, And these things must be easier to study
Speaker 2: in the lab. And then that doesn't really answer questions
Speaker 2: about what happens in reality where most of us live.
Speaker 1: Amen, Yes, it gets super complicated. So then another thing
Speaker 1: that makes it all complicated is that added to the
Speaker 1: plastic are chemicals that help you, for example, make plastic
Speaker 1: that are soft and are like easier to move. So
Speaker 1: for example, if you think of your water bottles, that's
Speaker 1: you can squeeze those, it bends a little bit. But
Speaker 1: then there's other chemicals that make plastics stiffer and harder.
Speaker 1: So for example, if you have a Nalgene bottle, when
Speaker 1: you squeeze that, it doesn't have much give. And so
Speaker 1: these chemicals that we add to the plastic can also
Speaker 1: cause problems in addition to the plastic. So for example,
Speaker 1: there's a class of chemicals called thalates. What it's pH thh.
Speaker 2: What pH that's not allowed?
Speaker 1: No, not in the English language. It shouldn't be. But
Speaker 1: so I'm just gonna thallates. I'm just gonna call I'm
Speaker 1: gonna pretend to the p is silent. The pH is silent.
Speaker 1: And these tend to be used to soften plastics, and
Speaker 1: they're pretty common in our bodies. So there was a
Speaker 1: survey done in eight to ten out of the baby's
Speaker 1: surveyed had thollates in their body, and nearly all of
Speaker 1: the adults that were surveyed it had them too. And
Speaker 1: this chemical is associated with reduced sperm count and motility.
Speaker 2: No, I know, I don't like that. That's not good.
Speaker 1: No, But the results here are mixed. So like, if
Speaker 1: you were making a million sperm and now you make
Speaker 1: nine hundred and fifty thousand sperm, should you care? And
Speaker 1: the answer is, maybe.
Speaker 2: Those are fifty thousand of my boys we're talking about here.
Speaker 1: You weren't gonna make use of all those boys anyway, Daniel.
Speaker 1: So there was a study that was looking at like
Speaker 1: people who had various amounts of exposure to this stuff
Speaker 1: and how long it took for them and their partner
Speaker 1: to get pregnant or you know, for the woman to
Speaker 1: get pregnant. Yeah, And it looked like there wasn't necessarily
Speaker 1: an association between exposure to a certain kind of thallate
Speaker 1: and how long it took to get your partner pregnant.
Speaker 1: And so the point is, maybe sperm counts are lower,
Speaker 1: but that doesn't necessarily result in infertility issues all the time.
Speaker 2: All right, But sperm counts I think are dropping anyway, right,
Speaker 2: and we've been talking about how there's fertility issues already,
Speaker 2: so anything that pushes sperm counts lower is definitely not
Speaker 2: going to be good for fertility, right. I think you're
Speaker 2: arguing that this is a small effect, but still a
Speaker 2: small effect on average can have some measurable impact on
Speaker 2: the number of babies.
Speaker 1: Born, right, Yes, And there are some communities who would
Speaker 1: argue that a big part of the decline infertility could
Speaker 1: be because of things like plastic related chemicals in our
Speaker 1: water or whatever are being ingested with the food that
Speaker 1: we eat, and so yeah, it could play a role,
Speaker 1: and it could play a role in aggregate. Maybe it's
Speaker 1: just playing a small role in that overall trend. There's
Speaker 1: some work done in lab animals like mice that do
Speaker 1: find definitely quantifiable impacts from exposure to thalites on the mice.
Speaker 1: And so the question is if a mouse has infertility,
Speaker 1: does that mean that a human's going to have infertility?
Speaker 1: We don't necessarily know, And often animals in the lab
Speaker 1: are exposed to much higher concentrations of the chemicals than
Speaker 1: we are exposed to on a day to day basis,
Speaker 1: for example, and so it's hard to know how to
Speaker 1: tie those things together. But there is some risk that
Speaker 1: these chemicals are having some impacts on fertility related issues.
Speaker 1: But we don't really know how much we should be
Speaker 1: worried about this happening for humans yet.
Speaker 2: All right, So, Kelly's given us two reasons to worry
Speaker 2: so far. They can trap stuff, they can be toxic chemicals.
Speaker 2: When we come back from the break, we're going to
Speaker 2: hear about more reasons to worry, including Daniel's number one
Speaker 2: reason to worry about microplastics. Oh okay, we're back and
Speaker 2: we're talking about all those little bits of plastic that
Speaker 2: are everywhere in the earth and in you right now
Speaker 2: swimming through your body? Are hundreds thousands? How many bits
Speaker 2: of micropack are in each of our listeners?
Speaker 1: Kelly, Oh I that would be very hard to quantify.
Speaker 1: I don't know exactly how many pieces are in each
Speaker 1: of us.
Speaker 2: We want numbers. I want an individual list of numbers
Speaker 2: for each listener.
Speaker 1: Okay, well, give me a lot more money. And also
Speaker 1: there's going to need to be a lot of slaughter
Speaker 1: because to get those numbers usually requires an autopsy. So
Speaker 1: let's just say we probably all have at least a
Speaker 1: microplastic piece in us, and that's probably quite an underestimate.
Speaker 2: All right, but it sounds like if you really want
Speaker 2: to know, and you're willing to volunteer for an autopsy,
Speaker 2: Kelly will give you a solid answer. Nope, that's a no. Okay,
Speaker 2: that's a nope. Do not ship your body to Kelly
Speaker 2: to get an answer to this question, turns out nope,
Speaker 2: All right, nope.
Speaker 1: Oh so you said you were going to tell us
Speaker 1: your number one fear from microplastics, So go ahead, let's
Speaker 1: hear that.
Speaker 2: Yeah, Well, my number one reason to worry about microplastics
Speaker 2: is we don't understand the body. It's a big, complicated system,
Speaker 2: and there's lots of things that we do to it
Speaker 2: all the time that we don't understand how it works.
Speaker 2: Like I think thailan All still not fully understood. Why
Speaker 2: does thilan All work, or why do all these sechoactive
Speaker 2: medications work, And so there's just a lack of a
Speaker 2: mechanistic understanding of how this is how the body works.
Speaker 2: It seems to me like you just throw a bunch
Speaker 2: of plastic in there. You can't predict what's going to happen,
Speaker 2: and so many weird and terrible things are happening to
Speaker 2: people all the time, it's hard to know like how
Speaker 2: much of this is due to eating plastic or not
Speaker 2: eating plastic. And so to me, the number one concern
Speaker 2: is something we can't predict because the system is too complicated.
Speaker 1: And I think that is absolutely spot on. Yeah, I
Speaker 1: totally agree with you. And one point that I want
Speaker 1: to go back to really quick. We were talking about
Speaker 1: thalates and there are possible impacts on the human body.
Speaker 1: I want to be clear that we do know that
Speaker 1: at very high doses, at high exposure, these things definitely
Speaker 1: are bad. So the question isn't thalates good or bad?
Speaker 1: The question is thalates at very low concentrations are they
Speaker 1: bad enough that we want to give up all of
Speaker 1: the benefits we get by having thalates. And there's another
Speaker 1: chemical that we have the same discs, and that chemical
Speaker 1: is bis phenol a, And just like with thalites, we
Speaker 1: don't totally understand whether we need to be worried about
Speaker 1: it and how much we need to be worried about it.
Speaker 1: But we know that this finyl a acts like estrogen
Speaker 1: in the body. So in some cases it mimics estrogen,
Speaker 1: making your body think there's more estrogen, and in other
Speaker 1: cases it will like bind to receptor where estrogen should
Speaker 1: be and now estrogen can't get to it, and so
Speaker 1: your body should be getting a message from estrogen and
Speaker 1: that message isn't going through.
Speaker 2: And so this is a great example. People are like, BPA,
Speaker 2: what could it do? It's probably fine. O turns out
Speaker 2: maybe it's not fine.
Speaker 1: Yeah, And there was a study that found that about
Speaker 1: ninety three percent of people have BPA in their urine,
Speaker 1: so just about all of us are exposed to it.
Speaker 1: And for all of these chemicals, you might be most
Speaker 1: worried if a fetus or a baby is being exposed
Speaker 1: when like tons of development stuff is happening. And so
Speaker 1: there were rules saying like, hey, look we need a
Speaker 1: lot less bysfhinyl a in things like baby bodels because
Speaker 1: we're worried about what tinkering with estrogen could do. There's
Speaker 1: some evidence that it's associated with increased blood pressure, type
Speaker 1: two diabetes, cardiovascular disease. Long down the road, it also
Speaker 1: can impact the brain and the prostate gland of feces
Speaker 1: and stuff. Lots of reasons to worry.
Speaker 2: You said prostate gland of feces, but I think you
Speaker 2: mean fetuses.
Speaker 1: I did I feces.
Speaker 2: You just got poop on the brain. I get it.
Speaker 1: No I do, I do. Sorry, the brain and prostate
Speaker 1: gland of fetuses not feces. Anyway, lots of reasons to worry.
Speaker 1: So we tried to cut down on the use of
Speaker 1: byspinyl a. But the problem is that this chemical is
Speaker 1: really helpful for making plastics stiffer and harder, and so
Speaker 1: we've replaced bisphinyla with something that has a very similar
Speaker 1: shape because we want that same shape so that we
Speaker 1: still get our nice hard plastics. So we've replaced it with,
Speaker 1: for example, bisphinyl s, and we think that actually, maybe
Speaker 1: this other thing does a lot of the same stuff
Speaker 1: to our body that bisphinyla does. So when you see
Speaker 1: a bottle that says doesn't contain BP, that doesn't mean
Speaker 1: that it doesn't contain a very similar bisfunyl thing. So yeah,
Speaker 1: it's hard to replace these things while still keeping the plastics.
Speaker 1: We love doing the things that we love them to do.
Speaker 2: I love those indications on food that make you feel like, oh,
Speaker 2: it's healthy, Like when you look at jolly ranchers and
Speaker 2: they say fat free and you're like, yeah, that's because
Speaker 2: it's one hundred percent sugar. That's right, that's right, doesn't
Speaker 2: make it a health food.
Speaker 1: I like things that are like cholesterol free. I'm like, well, yeah,
Speaker 1: because it it couldn't have cholesterol in it, because we
Speaker 1: know where cholesterol comes from. And it's like, no rat
Speaker 1: feces in this. It's like, well, it shouldn't have rat feces,
Speaker 1: and what does that imply about the other material?
Speaker 2: Anyway, It's but I do appreciate the nuance here that
Speaker 2: you could say, let's just get rid of all of it.
Speaker 2: But you're right that plastics have improved our lives and
Speaker 2: there's positivity there. And it sounds like we're being, you know,
Speaker 2: shills for big microplastics, as ironic as that name is,
Speaker 2: but it's true that, you know, you wouldn't want to
Speaker 2: just get rid of plastics even if there is a
Speaker 2: cost to human health, because it also saves lives. Right,
Speaker 2: having these medical supplies et cetera, et cetera does save lives.
Speaker 2: And so really the question, as always, is a nuanced one.
Speaker 2: It's like, does it do more harm than good?
Speaker 1: Yeah? And so let's dig in for a second into
Speaker 1: all the reasons why it's hard to really understand why
Speaker 1: this stuff is bad for people. So one we talked
Speaker 1: about how you can cough, sneeze, poop, or pee a
Speaker 1: lot of this stuff out. So just because you're exposed
Speaker 1: to something like bisfinil A doesn't mean that your body
Speaker 1: isn't going to excrete it before it causes any damage
Speaker 1: or break it down before it causes any damage. But
Speaker 1: maybe it is causing damage, and so we need to
Speaker 1: research this a lot more to figure out how we
Speaker 1: get exposed to it, how our bodies respond to it,
Speaker 1: how much of it is bad. But there does seem
Speaker 1: to be a move, for example, in Europe to decrease
Speaker 1: the amount of allowable things like bisfineles, because we are
Speaker 1: deciding as the data comes in, oh, this is a
Speaker 1: little scary, we don't want to risk it. The other
Speaker 1: problem is that plast sticks come in loads of shapes
Speaker 1: and sizes, and some of them are more likely to
Speaker 1: get into our bloodstream, for example, than others, and when
Speaker 1: they break down, they break down into thousands of different chemicals,
Speaker 1: many of which we haven't looked at for health impacts yet.
Speaker 1: So it could be that like ninety percent of plastics
Speaker 1: are okay, but there's ten percent that break down into
Speaker 1: super toxic stuff and that's what's causing the problem, or
Speaker 1: maybe all the chemicals that it breaks down into are bad.
Speaker 1: I don't want to sound like you've got me worried
Speaker 1: now that I sound like I'm a shill for big microplastic.
Speaker 1: This stuff is complicated, and you need to decide on
Speaker 1: your own how worried you are about it. We also
Speaker 1: don't have very good methods for counting and quantifying plastics
Speaker 1: in the human body. I mentioned that you can look
Speaker 1: at this stuff during an autopsy, but then once you've
Speaker 1: got these micro or these nanoplastics that you've collected from
Speaker 1: an autopsy, how do you know what kind of plastics
Speaker 1: they were in particular, and what about it was bad?
Speaker 1: So you know, maybe one plastic in the brain has
Speaker 1: thali attached to it and one has bispinyl a, And
Speaker 1: how do you quantify the total impact of all of
Speaker 1: that on our bodies. It's very complicated when there's lots
Speaker 1: of stuff interacting. And one thing that also makes it
Speaker 1: complicated is that for things like bysfhinyla, this old phrase
Speaker 1: the dose makes the poison doesn't really stand. So for
Speaker 1: things like mercury, probably the more mercury, you ingest the
Speaker 1: worse it is, we don't want to have a lot
Speaker 1: of that. But with a lot of hormones, they have
Speaker 1: this weird way of interacting with our body where low
Speaker 1: doses and high doses can have the biggest impact, but
Speaker 1: intermediate doses sometimes have low impacts. So it's almost like
Speaker 1: the letter you if you're looking at it on a graph.
Speaker 1: And so it's not necessarily the case that more and
Speaker 1: more and more and more is worse, but having a
Speaker 1: little bit could be really bad, or having a lot
Speaker 1: could be really bad, And so it just makes it
Speaker 1: even harder to figure out these associations and try to
Speaker 1: get a handle on how bad and what doses are
Speaker 1: okay for people.
Speaker 2: Okay, then give me a overview of like potential things
Speaker 2: to worry about in terms of effect on human health.
Speaker 2: I'm not going to have more kids, so I don't
Speaker 2: really need to worry about my boys swimming anymore. But
Speaker 2: beyond fertility, what concerns are there for human health?
Speaker 1: Okay, So again we don't really understand the mechanism totally
Speaker 1: for some of this stuff, but one concern is that
Speaker 1: there might be earlier puberty. So, for example, from the
Speaker 1: nineteen seventies to today, I think puberty has moved up by
Speaker 1: something like a year on average. And so the question
Speaker 1: is do having all of these chemicals that mimic estrogen
Speaker 1: in the environments, is that, for example, moving up puberty
Speaker 1: time for women and women who enter puberty earlier, I
Speaker 1: believe they have a higher risk of things like breast
Speaker 1: cancer later on. So there could be bigger implications than oh, man,
Speaker 1: I've got my period a year earlier. It could have
Speaker 1: more health impacts down the line. There's also some proposed
Speaker 1: link between obesity and microplastics. So obesity has increased in
Speaker 1: the United States, you know, roughly along the line as
Speaker 1: are increasing use of plastics. But a lot of things
Speaker 1: have changed about the United States over that amount of
Speaker 1: time too. You know, it's probably easier to get fast
Speaker 1: food and less healthy food, So it's really hard over
Speaker 1: time to tease these things apart. But plastics could be
Speaker 1: playing a role because we have seen that some kinds
Speaker 1: of plastics and the chemicals that they carry into our
Speaker 1: bodies change the way our bodies metabolize food and the
Speaker 1: way our bodies make fat cells and stuff like that.
Speaker 1: And we found that lab animals and domestic pets are
Speaker 1: more likely to be obese as well, and those are
Speaker 1: animals that are exposed to plastics a lot because of us.
Speaker 1: And so you know, maybe we're seeing an indirect effect
Speaker 1: in our lab animals and our pets that.
Speaker 2: We have to be very cautious in concluding anything from
Speaker 2: correlation studies, right, because yes, these things could just be random.
Speaker 2: Like if you've seen the correlation between ice cream and murder, right,
Speaker 2: it's very tight. Doesn't mean ice cream causes murder. It
Speaker 2: means you tend to have ice cream more in the summer,
Speaker 2: and people tend to commit murderers more in the summer,
Speaker 2: maybe because they're not getting enough ice cream. Actually, so
Speaker 2: maybe ice cream suppresses murder.
Speaker 1: Who knows, that's right. Maybe I think we probably all
Speaker 1: need more ice cream.
Speaker 2: Now we're big shells for ice cream.
Speaker 1: Great, I'm okay with that that.
Speaker 2: I'm okay with microplastic free big ice cream. All right,
Speaker 2: there you go. So we're worried about puberty, we're worried
Speaker 2: about ovcity. What else should we be worried about?
Speaker 1: There's some concern about cardiovascular issues. So, for example, there
Speaker 1: was a twenty twenty four paper in the New England
Speaker 1: Journal of Medicine, where people went through surgeries to remove
Speaker 1: plaques in their arteries. So this is like removing the
Speaker 1: build up of stuff that was clogging up the stuff
Speaker 1: in the arteries leading to the heart. And after they
Speaker 1: removed that stuff, they put it under a microscope and
Speaker 1: they looked to see if they were microplastics in there,
Speaker 1: and about half of the people that they looked at
Speaker 1: had microplastics in there, a couple different kinds of microplastics.
Speaker 1: They tried to quantify the different kinds, but then they
Speaker 1: followed those people for thirty four months after the plaque
Speaker 1: was Removedeople who had microplastics in there were more likely
Speaker 1: to have encountered a myocardial infarction, a stroke, or death. Essentially,
Speaker 1: their heart was likely to have some additional problems in
Speaker 1: the like year and a half or more after plaque
Speaker 1: removal if those plaques had plastic.
Speaker 2: Infarction is a word. It's not just a typo for infraction.
Speaker 1: And infarction is an obstruction of the blood supply to
Speaker 1: an organ or region of tissue, typically a thrombosis or embolists,
Speaker 1: causing local death of the tissue.
Speaker 2: So yes, it's also a word that, for some reason
Speaker 2: is just hilarious. It's a word like weasel or booger, infarction.
Speaker 2: It just sounds funny to me. I don't know, I
Speaker 2: know it's not funny when it kills you, but it's
Speaker 2: a funny word.
Speaker 1: Yes, yeah, yeah, A booger is funny when it happens
Speaker 1: to you, and infarction is not. But uh, maybe a
Speaker 1: booger's not funny depending on the context. But anyway, it
Speaker 1: makes me laugh. So you mentioned that a problem with
Speaker 1: observational studies is that you don't know what is causing
Speaker 1: the correlation. So, for example, it could be that the
Speaker 1: people who had microplastics in their plaques are people who
Speaker 1: were more likely to I don't know, get McDonald's that
Speaker 1: are in those like plastic wrappers, and you know, something
Speaker 1: about their diet resulted in them having more microplastics, and
Speaker 1: then they didn't change that aspect of their life after
Speaker 1: the surgery, and that's what led to the problems they
Speaker 1: had down the road. So it's really hard to tease
Speaker 1: apart cause and effect and you know what is causing
Speaker 1: this problem when you're looking at an observational study.
Speaker 2: All right, So there's lots of reasons to worry, but
Speaker 2: we don't have a great mechanistic understanding or really an
Speaker 2: idea for what problems could be caused. So what can
Speaker 2: we do? What are your prescriptions for improving our lives?
Speaker 1: Yeah, so I'd say that the emerging picture is that
Speaker 1: there are reasons to potentially worry.
Speaker 2: There's always reasons to worry, Kelly.
Speaker 1: There's always reasons to worry, I know. And so you
Speaker 1: can decide how concerned the information we've talked about, how
Speaker 1: concerning that is to you. But there are some things
Speaker 1: you can do in your day to day life to
Speaker 1: protect the environment. Let's start with those. So one, there
Speaker 1: are like filters that you can get that go on
Speaker 1: your laundry machine to collect some of those microfibers so
Speaker 1: that they don't go into the wastewater treatment plant and
Speaker 1: then they don't go into the ocean. You can, you know,
Speaker 1: try to buy clothes that are meant to last a
Speaker 1: little bit longer so that you're not buying as many
Speaker 1: clothes and that would result in less you know, microplastics.
Speaker 1: You could take public transportation so that you're not wearing
Speaker 1: out your own tires. There's lots of little things that
Speaker 1: you could.
Speaker 2: Do you can invent flying cars so I don't need
Speaker 2: tires anymore.
Speaker 1: Well, I think some people are working on devices to
Speaker 1: collect plastic as they get released from tires, and that
Speaker 1: seems like it could be pretty tough. You'd maybe never
Speaker 1: get all of it, but you know, you could try
Speaker 1: to work on technologies that make this stuff easier to
Speaker 1: remove from the environment. But if you're worried about your
Speaker 1: own personal risk, some things that you can do include
Speaker 1: eating from glass or metal containers instead of plastic. If
Speaker 1: you have tupperware containers, don't wash them in your dishwasher
Speaker 1: because that gets really hot it starts breaking down the plastics.
Speaker 1: Those microplastics could come off in your food. Things like
Speaker 1: vacuuming regularly are important because you're dropping plastic fibers all
Speaker 1: the time from your clothes and they end up on
Speaker 1: the floor and then they can get kicked up into
Speaker 1: the air as you're walking around. Maybe not drinking bottled
Speaker 1: water because those tend to have plastics, but there's also
Speaker 1: plastic in tapwater. But if you get a reverse osmosis filter,
Speaker 1: you can take some of it out, but those are expensive,
Speaker 1: and if you remove the microplastics, you're also removing minerals
Speaker 1: and salts and stuff, and you might want to add
Speaker 1: some of that stuff back in. A lot of this
Speaker 1: stuff is complicated, so you need to decide what are
Speaker 1: your most likely exposure risks and how concerned are you,
Speaker 1: because again there are trade offs, maybe a lot of
Speaker 1: this stuff at doses. You know, like I live in
Speaker 1: the middle of nowhere. I don't probably breathe in a
Speaker 1: lot of tire stuff. My water comes from the ground,
Speaker 1: and while groundwater does sometimes have some plastics, my groundwater
Speaker 1: where I am probably doesn't have a lot of it.
Speaker 2: So we should all move in with you.
Speaker 1: It sounds like I mean no, no, actually, because then
Speaker 1: then it wouldn't be quite as pristine. But anyway, like,
Speaker 1: I'm not too worried about my exposure to plastics because
Speaker 1: I use a lot of ceramic and stainless steel stuff,
Speaker 1: so I'm not too worried. But you know, you should
Speaker 1: think about the various ways you encounter plastic in your
Speaker 1: life and then decide if you are concerned or not,
Speaker 1: and if you want to make any changes, it's up to.
Speaker 2: You, And as is my habit, the night before we record,
Speaker 2: I usually ask Katrina what she thinks about an episode
Speaker 2: just to hear she has some ideas. So I asked
Speaker 2: her what she thought we could do to reduce our microplastics.
Speaker 2: And here's what she had to say.
Speaker 8: Well, eating fiber forms a matrix that will protect you
Speaker 8: from all toxins. Think of it like a brit of filter,
Speaker 8: where it's sucking up the toxins and preventing them from
Speaker 8: being absorbed into your body. So if you're eating fiber,
Speaker 8: then you've got this gel that sticks with you down
Speaker 8: to your colon. If there's also microplastics in your food
Speaker 8: and water, it gets sucked up into that so that
Speaker 8: it doesn't get absorbed by your intestinal cells.
Speaker 2: So Katrina is big on fiber, so maybe no surprise
Speaker 2: that she prescribes fiber for everybody.
Speaker 1: Yeah, I was going to ask if the answer to
Speaker 1: every question in the Whites and household is beans.
Speaker 2: Beans, She seeds beans fiber. It's good. She's just rooting
Speaker 2: for the microbes inside everybody to help with the microplastics.
Speaker 1: Well, we could probably all use more fiber anyway. And
Speaker 1: there are some studies in mice, for example, that find
Speaker 1: that microplastics disrupt the gut microbiome, so fiber can help
Speaker 1: you in the battle against plastics in a lot of
Speaker 1: different ways, and so, you know, I want to be
Speaker 1: clear throughout this episode. You know, I've tried to make
Speaker 1: sure I was including caveats about whether or not this
Speaker 1: is likely to be important, Like I don't want people
Speaker 1: to be freaking out. There are some reasons to be concerned,
Speaker 1: but at the moment, there's just so many different places
Speaker 1: we can encounter plastics, and so many different kinds of plastics,
Speaker 1: and so many different contingencies that matter, like where the
Speaker 1: plastic was before it got to you. That we just
Speaker 1: don't have a very good handle on this problem yet.
Speaker 1: And this is all the more reason to invest in
Speaker 1: basic science so we can try to understand this better.
Speaker 1: But like so many risks in life, you got to
Speaker 1: kind of decide for yourself, how concerned am I going
Speaker 1: to be given what we know about this.
Speaker 2: So don't worry too much, don't worry too little, worry
Speaker 2: just the right.
Speaker 1: Amount that's right, Just the right amount. Good luck with that.
Speaker 1: And the reason we talked about microplastics today is because
Speaker 1: a listener sent us an email saying I would love
Speaker 1: to know more about microplastics. So I sent this episode
Speaker 1: to them, and let's see what they had to say.
Speaker 9: Plastic is a wonderful material and all its different applications
Speaker 9: and all the different fields where it's an essential material.
Speaker 9: Although I don't believe that we.
Speaker 10: Need to be more picky how we use plastic, and
Speaker 10: we need to cut some products from our lives, especially
Speaker 10: the disposed of single use ones that are quite unnecessary.
Speaker 10: I believe I'm deeply concerned for the effect microplastics have
Speaker 10: on smaller creatures, especially.
Speaker 9: Ocean creatures as you mentioned in the episode, and.
Speaker 11: The effects that they may have on their larger food
Speaker 11: chains and ecosystems. It might sound bleak, but I'm less
Speaker 11: so concerned for the effects on human health, as we are,
Speaker 11: of course the responsible ones. But thank you Daniel and
Speaker 11: Kelly for the episode is informative. I learned some new things,
Speaker 11: and thank you for picking my suggestion.
Speaker 1: Thank you very much for that feedback. We did end
Speaker 1: up focusing a lot on human aspects of impacts of microplastics,
Speaker 1: but there's definitely evidence that microplastics and aquatic ecosystems are
Speaker 1: bad and impact a variety of different organisms in negative ways.
Speaker 1: So I think at a minimum, it would be important
Speaker 1: for all of us to think about how we can
Speaker 1: cut back on plastics in our lives, and we should
Speaker 1: think about what we're doing too organisms beside ourselves. So yes,
Speaker 1: thank you for making that important point.
Speaker 2: All right, well, thanks everyone for sending in your questions,
Speaker 2: for being curious about the nature of the world. Though
Speaker 2: we don't have a clear prescription about how you should
Speaker 2: live your life, at least now you're better informed about
Speaker 2: what we do and don't know about microplastics.
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