How bad are microplastics?

00:00:07
Speaker 1: The history of plastic is intimately tied to the history of the game of billiards. In the eighteen sixties, the billiard's industry had a problem. The game was super popular, but it was hard to keep up with the demand for high end billiard balls because the material used to make the balls was limited. The material was elephant tusks, and it took about two tusks to make a complete set of balls. A major billiard ball company offered a ten thousand dollars reward for anyone who could come up with a sturdy alternative. John Wesley Hyatt was inspired by this call, and he came up with an alternative to tusks that became the first industrial plastic. Now, the initial prototypes had the downside that they were highly flammable, and there were rumors that they would sometimes explode upon impact during a game. Or maybe that's an upside because it would make the game a lot more exciting. But anyway, today plastics are ubiquitous. They're in our tires, our clothes, they line our paper cups, they make disposable medical equipment which helps protect us from transmissible diseases, and the microphone in computer that I'm using to record this episode have plastic in them too. It's kind of hard to imagine life without plastic. We're probably all aware that plastic has downsides too. We're not really good at disposing of it properly, for example, And there's now garbage patches in the ocean, which are spots where currents have aggregated the trash we've released into the sea. And we've probably all seen images of animals like turtles and birds that have died from consuming or getting trapped by large pieces of plastic. And those are the easy to see problems. In the last decade or so, we've become more concerned with the plastics that are harder to see, the micro and the nanoplastics. These are bits of plastic less than five millimeters in length, which is like about the length of an ant, and smaller, much smaller. Some of these tiny plastics are made on purpose for use in things like cosmetics, and some are just the teeny tiny bits of bigger pieces of plastic that have broken down over time. These tiny pieces of plastic are now found around the globe. Even pristine environments that rarely see people will see our plastics because super small plastic pieces go airborne, and they move with air currents around the world closer to home. We've found very small pieces of plastic in human hearts, brains, testicles, and more. It's even been found in baby maconium, which is a baby's first poop, so it's working its way through a fetuses as well. How worried should we be? This is an episode of Daniel and Kelly's Extraordinary Universe, So you've probably already guessed that the answer is, well, we don't really know. We haven't been studying this for very long, and as we'll discuss, it's a hard problem to study, and it's not feasible or maybe even design mirable to stop using plastics entirely. So what do we do about microplastics if we decide we should be worried? Welcome to Daniel and Kelly's Plastic Universe.

00:03:24
Speaker 2: Hi. I'm Daniel. I'm a particle physicist, and I'm a parent, so I always think we should be worried.

00:03:30
Speaker 1: Hello. I'm Kelly Wayne or Smith. I study parasites and space, and I have severe anxiety, so I also always worry, and actually being a parent made that a little bit worse.

00:03:40
Speaker 2: All right, Well, then my question for you is do you think worrying helps? I mean, I know this is like culture of worrying. Jewish mom send each other messages like start worrying. Now you could probably like hire a room full of Jewish mom somewhere, like worry on your behalf? Have you know nine dollars an hour or ninety nine? I don't know think that worrying helps. Does it make us think deeply about all the possible issues? Does it make us better scientists? What do you think?

00:04:07
Speaker 1: I think?

00:04:08
Speaker 2: What's the upside of worrying?

00:04:09
Speaker 1: It depends. I think so. I think Zach doesn't worry enough. And so there have been a couple of times where I've felt like I've had to step in to get the worrying level up to the right amount so that we could take care of some problems that needed to get taken care of.

00:04:24
Speaker 2: Was that when your stove was on fire recently? For example?

00:04:26
Speaker 1: Uh no, I I actually when I opened up the stove and I looked inside and I saw the fire, which was not my food, thank you very much, It was something else. My first thought was I should call Zach, and my second thought was what would he do? I don't need to call Zach. And then it turned out that Zach's brother had given me a fire extinguisher, So who I needed was Zack's brother. Thank you, Marty, and I pulled out the fire extinguisher. Everything was okay, I need to change the heat element or whatever. But I think you need to worry a little, but you need to not overdo it. And I massively overdo it. Zach underdoes it, and then I think we average are worrying and we get the right amount of stuff done. But what do you think, Well.

00:05:11
Speaker 2: I have this friend who's a neuroscientist who thinks that worrying is what makes us better scientists, because you like wake up in the midlight you're like, wait a second, what if this part of that paper is wrong? What if blah blah blah blah blah, How would I know for sure? And then you come up with another test to verify that, And so it really helps make your science bulletproof because you sort of put yourself in the mind the reviewer and ask all the critical questions, and you worry about being embarrassed in front of your colleagues when your results are shown to be an artifact. So I think that it is helpful in that sense, and it also helps you prepare for eventualities. Like the reason I buy insurance is because I worry about stuff, right, But I agree that it can go too far. It can be unproductive for sure. But you know, I think on this podcast we aim for just the right level of worrying. We aim to educate you enough to make knowledgeable choices about your life.

00:06:02
Speaker 1: Right, Yes, that's right, that's exactly right.

00:06:04
Speaker 2: And so you hear all about disgusting parasites you will probably never get and don't have to worry about. But now you know enough not to go swimming with snails in Venezuela or whatever it was.

00:06:15
Speaker 1: Well, and you know what questions to ask your doctor when you go see here you go, Yeah, something like that. That's our goal.

00:06:22
Speaker 2: That comes from a person who has repeatedly gone to the doctor convinced he had toe cancer.

00:06:27
Speaker 1: Toe cancer in particular. Is there something weird about your toes that that makes you think they're cancer?

00:06:33
Speaker 2: Is No, I am just a hypochondriac and am capable of convincing myself that's some weird thing. It's probably cancer and a better of the doctor. And I'm the kind of guy who shows up the doctor without a list. Here's seven reasons why I'm dying. Let's go through them.

00:06:47
Speaker 1: Ah.

00:06:48
Speaker 2: And you know, a good doctor is the one that, like knowledgeably but patiently walks you through the reasons why you're not dying today.

00:06:56
Speaker 3: That's right.

00:06:56
Speaker 1: So I came. I came with my own list for the same thing for the doctor. And after I went through the list, the doctor said, can I ask you some questions? Can I give you a survey for anxiety? And we discovered Kelly doesn't have cancer. Kelly has severe anxiety. So thank you to that doctor for listening to what I wasn't saying.

00:07:16
Speaker 2: And so today we're actually doing an episode about something I've been wondering about whether we need to be worried about, but I wasn't knowledgeable enough about it to know whether worrying was justified or just my anxiety.

00:07:29
Speaker 1: And you know what, it's nice to get clear answers, but you're not getting that today. Daniel also, sorry, but at.

00:07:36
Speaker 2: Least I'm going to be brought up to the forefront of current.

00:07:38
Speaker 1: Knowledge, right, that's right, that's right.

00:07:40
Speaker 2: You will me so I won't have to be worried that I don't know enough to worry. So there you go.

00:07:45
Speaker 1: All right, there you go. Well, so let's start by seeing what the general public thinks of this question, or at least what the extraordinaries, who are probably not a random subset of the general public. Let's see what our extraordinaries think. So I asked, should we be worried about microplastics or why not?

00:08:01
Speaker 4: Probably not. I've seen articles that microplastics are everywhere and they're going to ruin our health in the environment, but I've never seen them give irrelevant context, such as what the biological effects are. I'm open to learning more, but in the meantime, I'm not too worried about it, and I'll continue to worry instead about climate change and my own diet.

00:08:21
Speaker 5: I certainly believe that we should be worried about microplastics. First of all, there is a coating of plastic around the world so thick that anthropologists are considering naming our current epoch of the plastic scene because it'll form a permanent layer that doesn't even begin to show all the potential harmful effects of the microplastics.

00:08:46
Speaker 2: Our immune system simply has not evolved to remove plastics from our bodies, and the more they accumulate, then the more we can expect trouble.

00:08:55
Speaker 3: Microplastics have been discovered all over the globe, I believe in Antarctica. We don't know absolutely sure the link and mechanism to problems, but it can't be good.

00:09:08
Speaker 6: In about seventy five years, we went from there being none to now being so pervasive that they can be found in the deepest depths of the ocean and even in our brains. I would love to know what these materials can be doing to our health and the rest of the ecosystem, so we can support policies that limit its production and perhaps even help clean it up.

00:09:29
Speaker 7: Yes, I do think we should be worried about microplastics. We don't know how our bodies, animals, and the environment are affected by these things, and we should investigate more.

00:09:39
Speaker 2: All right, So a lot of people out there feel like there might be something to worry about. At least, it's somewhat alarming that there's plastics everywhere. We don't really understand what they might do or how they might interfere with the function of this incredibly complex Goldberg machine we call our bodies.

00:09:55
Speaker 1: Yeah, that's right, And I thought it was interesting. One of our listeners mentioned that to sometimes suggest we could call this era the plastic scene, because if you geologically dig through, you can see a layer where plastic has essentially been accumulating as we've made it go like airborne and all over the planet. And so I feel like, you know, if you look at human impacts first, you'll see like a layer that's a bit radioactive from all of our nuclear tests, and then you'll see a plastic layer. And you know, we've done a lot of beautiful things, but I don't feel like geology is telling a beautiful story.

00:10:26
Speaker 2: Wow, what a record we are leaving.

00:10:28
Speaker 1: Huh, that's right, that's right. But we do a lot of amazing things with plastics, right, And so one of the things that kind of frustrated me when I was you know, I tried to see how other people have covered this topic, and there's a lot of people being like, oh, plastics, they're horrible, and like, I get it. I get it. I'm an ecologist. I worry about the environment. I worry about the impacts on animals. I worry about the impacts on us, But plastics really make our lives a lot better, right, Like, I think you need to keep in mind the trade.

00:10:55
Speaker 2: Offs here, give me a top five reasons why plastics are good for humanity?

00:10:59
Speaker 1: Well, I mean, so we've got like all of the disposable plastic medical equipment that helps make sure that we don't transmit diseases to each other. That's pretty great. Most of our clothes now, even clothes that are made of natural fibers quote unquote, have some plasticky stuff in them. And you know, I think making clothing more affordable and making it so that everybody can afford to where things that make them feel nice is huge and great. And in general, I don't know that I'm going to go for all five because I don't know that people really care about Kelly's top five things. But in general, I think there's a lot of things that are now within the price range of the average American that wouldn't be if we had to use quote unquote natural substances. And natural substances aren't necessarily always better for the environment. So, for example, we started this episode with the story about wanting to find a different material to make billiard balls out of because we were using elephant tusks. Oh no, so everything's a trade off. You know, if we were to get all of our products from nature. That would be pretty damaging to the environment also, and so I don't know, I'm Kelly. So the message here is it's complicated. It depends you need to look at it from a number of different angles.

00:12:05
Speaker 2: Well, so tell me how long have we had plastic I imagine it's something that came about in the space age, like the sixties seventies, you know, Dow chemicals invented or something. I'm pretty fuzzy on the history here. Educate me.

00:12:18
Speaker 1: Well, So that billiard ball example, that was one of the first examples of someone making a plastic y substance. It was celluloid and it was a hard substance so that you could bounce billiard balls off of each other without having them like sort of dent and bend in ways that would impact how they moved. They were slightly flammable, which I mentioned in the introduction, and so if they spang together sometimes they would set on fire, which would actually make me watch a game of pool. And so, but large scale production didn't really start until the nineteen fifties. Around the nineteen fifties the nineteen sixties, like single use you know, plastic spoons, single use plastic everything really became fashionable as a way to make our lives easier, and they were really they were much less expensive than a bunch of the other stuff. And so since the nineteen fifties, the amount of plastic in our lives has been increasing at a tremendous rate. And that's the big plastic stuff.

00:13:10
Speaker 2: And so help me understand why, Like, if we knew how to make this stuff for one hundred years, why do we only really begin making it in large volume in the fifties. Was this after like post World War two industrialization or something else.

00:13:23
Speaker 1: I didn't look too much into the history of plastics, but my sense is that it did take a while to figure out the chemical processes. And so, you know, plastics as a category, like encompasses loads of different kinds of plastics that are good for a lot of different purposes. And so I think it took us a while to figure out how to make different kinds of plastics, what they're good for, how to industrially scale up so that we could, you know, use them for lots of different stuff. How do you make injection molds for this kind of stuff. I think all of that just took a while.

00:13:51
Speaker 2: All right, And so we're talking about plastic spoons and plastic medical equipment. I know Katrina uses it for her diabetes, she has these tubes, et cetera. But nobody's manufact cturing microplastics. What are microplastics exactly?

00:14:03
Speaker 1: Well, people are manufacturing microplastics as I understand it, the bulk of the plastics. So the bulk of the plastics is, you know, you get a plastic bag, you get a shirt with some plastic in it, and it ends up either in a landfill or it ends up in the ocean, and over time it breaks down. It could be because UV radiation is breaking it down into pieces. It could be because there are just fibers on your shirt that go airboard and they end up on the floor in your carpet in your home. So they come from big plastic breaking down, but they do also come from purposefully making small pieces of plastic. So for a while, it was fashionable to have microbeads in like exfoliation stuff, so like cosmetic stuff for like washing your face to help like move dead skin cells off. We now have rules in both the US and Europe against that kind of stuff, but you can still end up with microplastics in I think you can have them like in moisturizers. They almost act like ball bearings, just making it so that things go on a little bit smoother. But let's do some definitions here. Microplastics are defined as things that are five millimeters in size or less. That's true. Big, Yeah, that is pretty big. That's like an ant, right, that's something you could see. So anything five millimeters in size or less is a microplastic. But we also have a category called nanoplastics, and these are one micrometer in size or less, So these are probably not something you're likely to see.

00:15:27
Speaker 2: I hold on, microplastics are millimeter sized, nanoplastics are micrometer sized. Why don't they line up the name with the size, Like, why don't nanoplastics be nanometer and microplastics be micrometer? Wouldn't that make sense?

00:15:42
Speaker 1: That would make sense. And it's a bit ironic that the physicist is complaining about naming. But I'm not gonna say.

00:15:51
Speaker 2: You know what they say, Every accusation is a confession.

00:15:53
Speaker 1: That's right, that's right. I don't know who's to blame for this naming system, but yes, you're right, it's not intuitive.

00:16:00
Speaker 2: Pico plastics are one nanometer in size. That's all right. So we have microplastics, which are actually kind of big nanoplastics, which is super duper small. But how much of this really is around?

00:16:13
Speaker 1: First, I want to say, it's really hard to estimate. And while I was reading, the more recent papers are estimating more and more and more. And that's because we have better and better techniques for identifying smaller and smaller pieces of nanoplastic. So it's pretty easy, like by eye to count how many pieces of plastic fibers that are five millimeters long are in a water sample, for example, but looking at objects that are one micrometer or less is much harder. But there's an estimate that fifty one trillion microplastic particles are floating in our ocean. Trillion, trillion, trillion, I said, trillion, Yeah, oh my gosh. I read this book called A Poison Like No Other by Matt Simon, and it's all about microplastics. And he talks about how microplastics have been found in invertebrates in the Marianna ste Trench in the most remote mountainous regions you can go to, and like this has just permeated our entire world. So you know, when we drive down the road, we kick plastics off of our tires. Some of those go airborne. They take air currents, you know, to the ocean or across the ocean. Anywhere you go and sample, there's a really good chance that you are going to find a microplastic. I feel like I should at a caveat. I do feel like that book over sells what we know about the risks a bit. But if you are looking to be scared and you're looking to understand where all the microplastics are and how much of them are out there, that book is encyclopedic in its laying out of where we find these things and how they might be hurting us.

00:17:43
Speaker 2: I'm still having my mind blown by the number. Fifty one trillion. Yeah, more microplastics than there are stars in the galaxy. Like if Elon Musk wanted to buy all the microplastics for a penny each, he couldn't afford it. It's just hard to grapple with that number.

00:17:59
Speaker 1: It is, and again you should consider that number to have huge error bars. But for example, like there was a study looking at how many pieces of microplastics are in a bottle of water, and you you know, you think when you get a bottle of water, you're getting something that's nice and clean. Some bottles of water had essentially no pieces of plastic in a liter of water. Others had up to ten thousand particles of plastic in a liter of water.

00:18:20
Speaker 2: Oh boy, they should list on the ingredients including ten thousand part plastic.

00:18:24
Speaker 1: That's right, well, and a lot of it probably depends on like, you know, how were those water bottles stored. Did they get like left out in the sun for a few hours, because that breaks it down. Now plastics are starting to come out, and part of why the numbers get so big when you're talking about how many pieces of microplastics are in the environment is that they don't break down really well. So a big plastic bag will break down into much smaller component parts, but after that they don't break down the way something biological would. So when you've got biological stuff out there, you have decomposers that go and they eat it and they turn it into other stuff. There are some plastic war is that we're discovering, some like bacteria that can break down plastic, but in general, plastic is a thing that wasn't really in our environment in super high quantities in the past, so evolution doesn't necessarily have a way to break it down. Nature doesn't really have a way to break it down, and so they tend to accumulate and they break down to like some point where they're very small, and then often they appear to stop breaking down and then they just accumulate in these small sizes.

00:19:24
Speaker 2: So that's the thing I'm trying to wrap my head around is that plastic feels really stable, and you know, if you have a coke bottle, you expect it's still going to be there in one hundred years or a thousand years or whatever. So why do they break down at all? Like why do macroplastics turn into microplastics and then stop breaking down. I would expect they're either stable and a coke bottle is going to be here in a million years, or it's going to break down into like you know, atoplastics or whatever. The smallest fundamental bit of plastic is why do they sort of stop breaking down at the microplastic level.

00:19:54
Speaker 1: Well, I feel like that's a chemistry question, So I'm a little angry, but I'm kidding, But I think what's happening is that, like, you know, if you've got and I am joking, but you've got like a big piece of plastic.

00:20:10
Speaker 2: I just like how you said, I'm angry, but you said it with a smile.

00:20:14
Speaker 1: I'm hard to read too, so so you know, So imagine you've got like a plastic bag floating on the surface of the ocean. It's getting hit by UV radiation and that's starting to like break some of the bonds and break it into small parts. Those tiny pieces eventually get so small that they sort of break away from the rest of the bag and they start to sink. And as they sink, they sort of end up out of the reach of UV radiation, and they end up in the sediment, or they can end up in the soil, or they end up in the gut of something else. And in some cases they probably do keep breaking down. Like it's possible that our stomach acid breaks them down a little bit. But I think in general plastics, part of why they're so useful is because they are sturdy, and it takes a lot to break them down. And so maybe in a million years, of five millimeter fiber plastic piece will disintegrate into its like atomic pieces. But it's going to take a while.

00:21:03
Speaker 2: I see. I'm always amazed at the power of UV radiation. You know, in my house, if you burn something on a pan so you can't scrub it clean, you just put it outside for like a week, oh and the sun will break it up. It's amazing what UV radiation will do. Thank you, Southern California.

00:21:20
Speaker 1: Wait, wait, what is your Okay, what does your backyard look like? And how many animals have you attracted by doing that? Because I live in a place where animals want to be and they'd be licking those plates and it would be gross.

00:21:31
Speaker 2: That's fine, that's helpful. You know, some squirrel wants to use their you know, long teeth on that thing scrape some of that burnt oatmeal off the pan, like, please help us out.

00:21:39
Speaker 1: Man, all right, all right, some rabbit raccoon wants to Okay.

00:21:43
Speaker 2: All right, So we have plastics everywhere? How long has this sort of been something we've known about, Like plastics came about in large quantities like fifty seventy years ago. Was it very soon after that that we discovered that they were everywhere?

00:21:55
Speaker 1: I mean, I think when plastics started to go mainstream. It was, you know, easy to say plastics rolling down the street on a windy day or something like. I think we've been aware of macroplastics as as a problem for a long time. We're not very good at disposing of them. They tend to end up in the oceans, they tend to end up in animals. So we've known that's been a problem for a while. And it probably didn't surprise anyone when we first started talking about the fact that it breaks down into tiny pieces. But the first time of tension was really brought to this issue was when a marine ecologist named Richard Thompson wrote a paper about how he was collecting samples of sediment from beaches and estuaries and the subtitle zone in the United Kingdom, and he found microplastics in all of those places. And he looked at plankton samples, so these are like tiny little samples from the water column. And he looked at samples from the nineteen sixties and then at various dates getting closer to the present, and he found microplastics back from the nineteen sixties. But he also found that they were increasing over time and that even you could find them inside of the bodies of little invertebrates that live in the world, and so he noted that we don't know the environmental consequences of having this stuff in the water, but it's in the water. This problem is getting worse, but it still took about a decade before people started really digging in and particularly thinking about the impacts on human health.

00:23:15
Speaker 2: I love this example of digging through past samples collected for completely separate reasons and finding evidence or answers to a question you have later on. This is why you should always keep all of your samples and all of your notes, because who knows how it's going to be useful later. This is incredible. I love that.

00:23:33
Speaker 1: This is why museums are so important, because they do they keep those samples for you, and they're in a location where anybody can request them. So somebody, and you know, Peru, can think of a question that requires American water samples from the nineteen sixties or something, and if a museum has them, they can get those data. So anyway, yay for archiving, material behavior.

00:23:52
Speaker 2: Record keeping exactly all right. So it sort of came to the fore in the early two thousands, and then has the field sort of exploded in research.

00:24:00
Speaker 1: Yeah, the last ten to fifteen years, we've become a lot more interested in what it's doing in freshwater systems, what it's doing in oceans, what it's doing in our bodies. And let's take a break, and when we get back from the break, we'll start digging into that stuff. All right, So we have already established that microplastics are like everywhere, they're kind of unavoidable, and so let's start digging into you know, whether or not we need to worry about that. So one thing that you maybe need to worry about a little bit is that they bioaccumulate. So you might have heard this word from you know, Rachel Carson's book Silent Spring about DDT and how as you move up the food chain you get more and more concentrated levels of the chemicals. And so an example for microplastics is that there was a study looking at the soil in Mexico and they found that microplastics were a bit less than one particle typically in each gram, But if you pulled an earthworm out per gram of earthworm, you would find almost fifteen particles. So the earthworms were going through the soil and as they would ingest a piece of microplastic, it was like staying in them. And then they looked at chickens that were eating the earthworms, and there were one hundred and thirty particles per gram of chicken feces because you know, chickens were eating those. And so as you go up the food chain for the same like mass, you're finding more and more of these particles.

00:25:42
Speaker 2: So why do the earthworms accumulate them? Is it because they get filtered out of the soil and they stay in the earthworms Like there's something inside the earthworm that's like accumulating these things.

00:25:52
Speaker 1: So if you were to take a snapshot of what's inside of that earthworm, over like a year of an earthworm's life, and I don't know how long earth works live, it might not be a year, but like there might be a lot of particles that they ingested but they pooped out. But because they're going through so much soil, if you take a snapshot, they might have about fifteen particles per gram of earthworm because they're just moving through tons of soil and just sort of accumulating it as they go.

00:26:18
Speaker 2: But in order to accumulate it, they have to eat more than they poop, so they preferentially don't poop out microplastics, right, Otherwise they would have the same density as the soil. Like if you just pass a tube through the soil, it's going to have exactly the same density as the soil unless there's some filter in there that's like accumulating the microplastics or preferentially not pooping them out.

00:26:40
Speaker 3: Right.

00:26:40
Speaker 1: Yep, Yeah, that's a great point. You're right, they're accumulating them. They might poop some of them out, but in general they tend to be accumulating them.

00:26:46
Speaker 2: Yeah. Interesting, And so then the chickens eat those and then it gets more concentrated, and eventually when you're eating chicken, it's like half plastic.

00:26:54
Speaker 1: Yeah, not necessarily half plastic, but there's a fair bit of plastic in there. But one thing that's important in mind is that not all plastic matters the same from a standpoint of ingesting it. So you can get plastics in your body either by inhaling it because a lot of it goes airborne, or by ingesting it, and our bodies will defecate and urinate out a lot of the plastics that we consume, and if you breathe it in are what is it called our mucociliary elevator or something basically like we will like hawk it up. And actually maybe Matt wants to remove that sound effect.

00:27:31
Speaker 2: I don't think no, I think you should keep that. And I just wish that the audience could see the face you made.

00:27:40
Speaker 1: I was pretty expressive there. But so you know, you cough it up and then you can spit it out or swallow it and then it'll end up in your feces and anyway, all very gross. But our body has ways of getting rid of a lot of this stuff. But if you've got nanoplastics that are small enough, they can pass across our alveoli, which is a point in our lungs where our lungs are sort of in facing with our blood, and they can get into our bloodstream, or sometimes they can move across our gut into the rest of the body. So very small pieces can end up in other parts of the body where they're not going to get removed, or they're much less likely to get removed.

00:28:13
Speaker 2: And I've heard it said that we eat like a credit cards worth or a bottle cap worth of plastics every year or every week or whatever. Is that true, or is that people overworrying.

00:28:23
Speaker 1: There was a study that came up with that figure and that went like global, just like microplastics, it ended up everywhere. But there was another study that looked at the numbers a little more critically and they ended up deciding something like you would require twenty three thousand years or something like that to acquire the amount of plastic that that paper was estimating. And so that I think what most of us have heard about plastic getting in our body is pretty overblown. But that said, they have found plastic in human brains. So this was they did autopsies, so somebody had already paid away and they looked through the brain to look for plastics and they found it. Plastics have been found in plaques in our arteries, so when your arteries are getting clogged, there's some little pieces of plastic in there.

00:29:11
Speaker 2: Two.

00:29:11
Speaker 1: It has been found in testicles, kidneys, livers, like anywhere you can imagine, maybe not wanting plastic to be, plastic is there. And we found plastic in maconium. Daniel, do you remember, I mean I probably said it wrong, let's just be clear, but do you remember what maconium is? This is a word I only needed to know the definition of once or twice in my life.

00:29:32
Speaker 2: Oh, it sounds familiar. It sounds like mucus. Is it something gross inside the body?

00:29:38
Speaker 1: It's your baby's first poop?

00:29:40
Speaker 2: Oh, of course, yes, of course, mconium. I remember that. Now it's weird looking.

00:29:45
Speaker 1: Yeah, yeah, yes, it's weird looking, and it has plastic in it, and so that means it's probably microplastics or nanoplastics. Probably nanoplastics are passing from mom to the fetus, and the fetus is already, you know, defecating them out pretty soon. So we start our life with these microplastics with us.

00:30:02
Speaker 2: And we talked recently about water filtration systems and these amazing processes that clean up our water. Are microplastics too small to be filtered out?

00:30:12
Speaker 1: No?

00:30:13
Speaker 3: Not so.

00:30:13
Speaker 1: About ninety five percent of the microplastics that go into the wastewater treatment plant are removed through the various processes. There's a lot of microfibers that go to wastewater treatment plants because a bunch of the wastewater that goes to those treatment plants is from when we wash our laundry or from like our shampoos and body washes. And stuff, and our clothes every time we wash them are shedding loads of microplastics, and so lots of stuff gets to the wastewater treatment plants. About ninety five percent of it gets removed. Sometimes the sludge that gets collected at some of these plants will get used for other purposes, like as a fertilizer, and in that case the microplastics could get back into the environment. But if they're just put in a landfill, they're probably going to be fine. But a lot of them do still get through these wastewater treatment plants, and there were some data from twenty fourteen to twenty sixteen that estimated that something like eight to thirteen billion pieces of microbeads were being released from treatment plants into freshwater systems every day. And we're trying to use fewer microbeads, but there's still a bunch of these getting into our freshwater systems. But they also get into freshwater systems or our oceans through other routes. For example, a huge source of plastic is our tires, and so when we drive, we're wearing some of the plastic off of those tires, and that ends up either in the air or sometimes it ends up on the side of the road, and then the next time it rains, it takes those little pieces of plastic into our rivers and our lakes, and then in some cases it brings it to our oceans. And so yeah, those are some major sources of plastic into our aquatic systems.

00:31:49
Speaker 2: And so it's everywhere, and we found in our bodies, including our brains and all the other important bits. Why is this an issue or is it an issue or why might it be an issue for our health?

00:32:02
Speaker 1: Yeah, so we're not super clear on it. First all, I want to say that we've done some experiments on fish, and the fish seem to get kind of messed up. So fish end up, you know, they eat the little invertebrates that eat the microplastics, and then they accumulate it in their own body. And we found that microplastics can mess with things like how the fish move, It can damage their intestines. I think in some cases we found that it reduces their growth, and it seems to reduce their growth because it essentially like takes up space in their gut and they like feel like they've eaten, but they haven't eaten anything that's nutritious and so you know, they lose weight and that can impact their reproduction and stuff like that. So we know that there are some examples where it's been a problem in fish, but fish are swimming in this environment with loads of microplastics, so that might not tell us what we need to know about people. So here are some of the top issues that we worry about for microplastics. One of the main issues that we worry about is that these microplastics tend to to attract and stick to other stuff in the environment. So, for example, they stick to heavy metals PCBs, which are polychlorinated by phenols and some other kinds of toxic material, and they get what's called sorbed by the plastic.

00:33:18
Speaker 2: Absorbed, not absorbed, just sorbed.

00:33:22
Speaker 1: I think it's sorbed.

00:33:23
Speaker 2: Is that what the kids are saying these days?

00:33:25
Speaker 1: Wow, that's what the science kids are saying these days. Very generous to call us kids. But so they pick up these toxic compounds and then when they get into your body, they could release those toxic compounds. And so while a piece of plastic on its own might not cause a problem, if it's bringing, for example, mercury into your body and then depositing the mercury. The mercury could be the problem. Does that make sense?

00:33:50
Speaker 2: Yeah, absolutely it does.

00:33:52
Speaker 3: Yeah.

00:33:53
Speaker 1: Other things that tend to stick to these fibers include bacteria, and there's some concern that the way bacteria aggregate, they form like biofilms where maybe they could be sharing like antibiotic resistant genes or something. This sounded a little bit more speculative from what I could tell. But bacteria stick to them, and so do viruses, and so these pieces of plastic could be ways that bacteria and virus make it into your body.

00:34:15
Speaker 2: So basically they're dirty, they're not just weird and artificial and everywhere they're dirty.

00:34:21
Speaker 1: They are. But this also contributes to why they're so hard to study, right, because whether or not plastic is bad for you is going to depend on what the plastics saw before it went to you. So like the same kind of plastic and an environment with no mercury might do nothing, but the same kind of plastic in an environment where it can pick up mercury and then get to you could cause a lot of trouble.

00:34:42
Speaker 2: Yeah, exactly, And these things must be easier to study in the lab. And then that doesn't really answer questions about what happens in reality where most of us live.

00:34:50
Speaker 1: Amen, Yes, it gets super complicated. So then another thing that makes it all complicated is that added to the plastic are chemicals that help you, for example, make plastic that are soft and are like easier to move. So for example, if you think of your water bottles, that's you can squeeze those, it bends a little bit. But then there's other chemicals that make plastics stiffer and harder. So for example, if you have a Nalgene bottle, when you squeeze that, it doesn't have much give. And so these chemicals that we add to the plastic can also cause problems in addition to the plastic. So for example, there's a class of chemicals called thalates. What it's pH thh.

00:35:34
Speaker 2: What pH that's not allowed?

00:35:37
Speaker 1: No, not in the English language. It shouldn't be. But so I'm just gonna thallates. I'm just gonna call I'm gonna pretend to the p is silent. The pH is silent. And these tend to be used to soften plastics, and they're pretty common in our bodies. So there was a survey done in eight to ten out of the baby's surveyed had thollates in their body, and nearly all of the adults that were surveyed it had them too. And this chemical is associated with reduced sperm count and motility.

00:36:06
Speaker 2: No, I know, I don't like that. That's not good.

00:36:08
Speaker 1: No, But the results here are mixed. So like, if you were making a million sperm and now you make nine hundred and fifty thousand sperm, should you care? And the answer is, maybe.

00:36:21
Speaker 2: Those are fifty thousand of my boys we're talking about here.

00:36:23
Speaker 1: You weren't gonna make use of all those boys anyway, Daniel. So there was a study that was looking at like people who had various amounts of exposure to this stuff and how long it took for them and their partner to get pregnant or you know, for the woman to get pregnant. Yeah, And it looked like there wasn't necessarily an association between exposure to a certain kind of thallate and how long it took to get your partner pregnant. And so the point is, maybe sperm counts are lower, but that doesn't necessarily result in infertility issues all the time.

00:36:56
Speaker 2: All right, But sperm counts I think are dropping anyway, right, and we've been talking about how there's fertility issues already, so anything that pushes sperm counts lower is definitely not going to be good for fertility, right. I think you're arguing that this is a small effect, but still a small effect on average can have some measurable impact on the number of babies.

00:37:16
Speaker 1: Born, right, Yes, And there are some communities who would argue that a big part of the decline infertility could be because of things like plastic related chemicals in our water or whatever are being ingested with the food that we eat, and so yeah, it could play a role, and it could play a role in aggregate. Maybe it's just playing a small role in that overall trend. There's some work done in lab animals like mice that do find definitely quantifiable impacts from exposure to thalites on the mice. And so the question is if a mouse has infertility, does that mean that a human's going to have infertility? We don't necessarily know, And often animals in the lab are exposed to much higher concentrations of the chemicals than we are exposed to on a day to day basis, for example, and so it's hard to know how to tie those things together. But there is some risk that these chemicals are having some impacts on fertility related issues. But we don't really know how much we should be worried about this happening for humans yet.

00:38:15
Speaker 2: All right, So, Kelly's given us two reasons to worry so far. They can trap stuff, they can be toxic chemicals. When we come back from the break, we're going to hear about more reasons to worry, including Daniel's number one reason to worry about microplastics. Oh okay, we're back and we're talking about all those little bits of plastic that are everywhere in the earth and in you right now swimming through your body? Are hundreds thousands? How many bits of micropack are in each of our listeners?

00:39:01
Speaker 1: Kelly, Oh I that would be very hard to quantify. I don't know exactly how many pieces are in each of us.

00:39:07
Speaker 2: We want numbers. I want an individual list of numbers for each listener.

00:39:11
Speaker 1: Okay, well, give me a lot more money. And also there's going to need to be a lot of slaughter because to get those numbers usually requires an autopsy. So let's just say we probably all have at least a microplastic piece in us, and that's probably quite an underestimate.

00:39:24
Speaker 2: All right, but it sounds like if you really want to know, and you're willing to volunteer for an autopsy, Kelly will give you a solid answer. Nope, that's a no. Okay, that's a nope. Do not ship your body to Kelly to get an answer to this question, turns out nope, All right, nope.

00:39:39
Speaker 1: Oh so you said you were going to tell us your number one fear from microplastics, So go ahead, let's hear that.

00:39:44
Speaker 2: Yeah, Well, my number one reason to worry about microplastics is we don't understand the body. It's a big, complicated system, and there's lots of things that we do to it all the time that we don't understand how it works. Like I think thailan All still not fully understood. Why does thilan All work, or why do all these sechoactive medications work, And so there's just a lack of a mechanistic understanding of how this is how the body works. It seems to me like you just throw a bunch of plastic in there. You can't predict what's going to happen, and so many weird and terrible things are happening to people all the time, it's hard to know like how much of this is due to eating plastic or not eating plastic. And so to me, the number one concern is something we can't predict because the system is too complicated.

00:40:26
Speaker 1: And I think that is absolutely spot on. Yeah, I totally agree with you. And one point that I want to go back to really quick. We were talking about thalates and there are possible impacts on the human body. I want to be clear that we do know that at very high doses, at high exposure, these things definitely are bad. So the question isn't thalates good or bad? The question is thalates at very low concentrations are they bad enough that we want to give up all of the benefits we get by having thalates. And there's another chemical that we have the same discs, and that chemical is bis phenol a, And just like with thalites, we don't totally understand whether we need to be worried about it and how much we need to be worried about it. But we know that this finyl a acts like estrogen in the body. So in some cases it mimics estrogen, making your body think there's more estrogen, and in other cases it will like bind to receptor where estrogen should be and now estrogen can't get to it, and so your body should be getting a message from estrogen and that message isn't going through.

00:41:27
Speaker 2: And so this is a great example. People are like, BPA, what could it do? It's probably fine. O turns out maybe it's not fine.

00:41:35
Speaker 1: Yeah, And there was a study that found that about ninety three percent of people have BPA in their urine, so just about all of us are exposed to it. And for all of these chemicals, you might be most worried if a fetus or a baby is being exposed when like tons of development stuff is happening. And so there were rules saying like, hey, look we need a lot less bysfhinyl a in things like baby bodels because we're worried about what tinkering with estrogen could do. There's some evidence that it's associated with increased blood pressure, type two diabetes, cardiovascular disease. Long down the road, it also can impact the brain and the prostate gland of feces and stuff. Lots of reasons to worry.

00:42:12
Speaker 2: You said prostate gland of feces, but I think you mean fetuses.

00:42:16
Speaker 1: I did I feces.

00:42:19
Speaker 2: You just got poop on the brain. I get it.

00:42:22
Speaker 1: No I do, I do. Sorry, the brain and prostate gland of fetuses not feces. Anyway, lots of reasons to worry. So we tried to cut down on the use of byspinyl a. But the problem is that this chemical is really helpful for making plastics stiffer and harder, and so we've replaced bisphinyla with something that has a very similar shape because we want that same shape so that we still get our nice hard plastics. So we've replaced it with, for example, bisphinyl s, and we think that actually, maybe this other thing does a lot of the same stuff to our body that bisphinyla does. So when you see a bottle that says doesn't contain BP, that doesn't mean that it doesn't contain a very similar bisfunyl thing. So yeah, it's hard to replace these things while still keeping the plastics. We love doing the things that we love them to do.

00:43:13
Speaker 2: I love those indications on food that make you feel like, oh, it's healthy, Like when you look at jolly ranchers and they say fat free and you're like, yeah, that's because it's one hundred percent sugar. That's right, that's right, doesn't make it a health food.

00:43:27
Speaker 1: I like things that are like cholesterol free. I'm like, well, yeah, because it it couldn't have cholesterol in it, because we know where cholesterol comes from. And it's like, no rat feces in this. It's like, well, it shouldn't have rat feces, and what does that imply about the other material?

00:43:41
Speaker 2: Anyway, It's but I do appreciate the nuance here that you could say, let's just get rid of all of it. But you're right that plastics have improved our lives and there's positivity there. And it sounds like we're being, you know, shills for big microplastics, as ironic as that name is, but it's true that, you know, you wouldn't want to just get rid of plastics even if there is a cost to human health, because it also saves lives. Right, having these medical supplies et cetera, et cetera does save lives. And so really the question, as always, is a nuanced one. It's like, does it do more harm than good?

00:44:13
Speaker 1: Yeah? And so let's dig in for a second into all the reasons why it's hard to really understand why this stuff is bad for people. So one we talked about how you can cough, sneeze, poop, or pee a lot of this stuff out. So just because you're exposed to something like bisfinil A doesn't mean that your body isn't going to excrete it before it causes any damage or break it down before it causes any damage. But maybe it is causing damage, and so we need to research this a lot more to figure out how we get exposed to it, how our bodies respond to it, how much of it is bad. But there does seem to be a move, for example, in Europe to decrease the amount of allowable things like bisfineles, because we are deciding as the data comes in, oh, this is a little scary, we don't want to risk it. The other problem is that plast sticks come in loads of shapes and sizes, and some of them are more likely to get into our bloodstream, for example, than others, and when they break down, they break down into thousands of different chemicals, many of which we haven't looked at for health impacts yet. So it could be that like ninety percent of plastics are okay, but there's ten percent that break down into super toxic stuff and that's what's causing the problem, or maybe all the chemicals that it breaks down into are bad. I don't want to sound like you've got me worried now that I sound like I'm a shill for big microplastic. This stuff is complicated, and you need to decide on your own how worried you are about it. We also don't have very good methods for counting and quantifying plastics in the human body. I mentioned that you can look at this stuff during an autopsy, but then once you've got these micro or these nanoplastics that you've collected from an autopsy, how do you know what kind of plastics they were in particular, and what about it was bad? So you know, maybe one plastic in the brain has thali attached to it and one has bispinyl a, And how do you quantify the total impact of all of that on our bodies. It's very complicated when there's lots of stuff interacting. And one thing that also makes it complicated is that for things like bysfhinyla, this old phrase the dose makes the poison doesn't really stand. So for things like mercury, probably the more mercury, you ingest the worse it is, we don't want to have a lot of that. But with a lot of hormones, they have this weird way of interacting with our body where low doses and high doses can have the biggest impact, but intermediate doses sometimes have low impacts. So it's almost like the letter you if you're looking at it on a graph. And so it's not necessarily the case that more and more and more and more is worse, but having a little bit could be really bad, or having a lot could be really bad, And so it just makes it even harder to figure out these associations and try to get a handle on how bad and what doses are okay for people.

00:46:59
Speaker 2: Okay, then give me a overview of like potential things to worry about in terms of effect on human health. I'm not going to have more kids, so I don't really need to worry about my boys swimming anymore. But beyond fertility, what concerns are there for human health?

00:47:13
Speaker 1: Okay, So again we don't really understand the mechanism totally for some of this stuff, but one concern is that there might be earlier puberty. So, for example, from the nineteen seventies to today, I think puberty has moved up by something like a year on average. And so the question is do having all of these chemicals that mimic estrogen in the environments, is that, for example, moving up puberty time for women and women who enter puberty earlier, I believe they have a higher risk of things like breast cancer later on. So there could be bigger implications than oh, man, I've got my period a year earlier. It could have more health impacts down the line. There's also some proposed link between obesity and microplastics. So obesity has increased in the United States, you know, roughly along the line as are increasing use of plastics. But a lot of things have changed about the United States over that amount of time too. You know, it's probably easier to get fast food and less healthy food, So it's really hard over time to tease these things apart. But plastics could be playing a role because we have seen that some kinds of plastics and the chemicals that they carry into our bodies change the way our bodies metabolize food and the way our bodies make fat cells and stuff like that. And we found that lab animals and domestic pets are more likely to be obese as well, and those are animals that are exposed to plastics a lot because of us. And so you know, maybe we're seeing an indirect effect in our lab animals and our pets that.

00:48:45
Speaker 2: We have to be very cautious in concluding anything from correlation studies, right, because yes, these things could just be random. Like if you've seen the correlation between ice cream and murder, right, it's very tight. Doesn't mean ice cream causes murder. It means you tend to have ice cream more in the summer, and people tend to commit murderers more in the summer, maybe because they're not getting enough ice cream. Actually, so maybe ice cream suppresses murder.

00:49:07
Speaker 1: Who knows, that's right. Maybe I think we probably all need more ice cream.

00:49:11
Speaker 2: Now we're big shells for ice cream.

00:49:12
Speaker 1: Great, I'm okay with that that.

00:49:14
Speaker 2: I'm okay with microplastic free big ice cream. All right, there you go. So we're worried about puberty, we're worried about ovcity. What else should we be worried about?

00:49:24
Speaker 1: There's some concern about cardiovascular issues. So, for example, there was a twenty twenty four paper in the New England Journal of Medicine, where people went through surgeries to remove plaques in their arteries. So this is like removing the build up of stuff that was clogging up the stuff in the arteries leading to the heart. And after they removed that stuff, they put it under a microscope and they looked to see if they were microplastics in there, and about half of the people that they looked at had microplastics in there, a couple different kinds of microplastics. They tried to quantify the different kinds, but then they followed those people for thirty four months after the plaque was Removedeople who had microplastics in there were more likely to have encountered a myocardial infarction, a stroke, or death. Essentially, their heart was likely to have some additional problems in the like year and a half or more after plaque removal if those plaques had plastic.

00:50:19
Speaker 2: Infarction is a word. It's not just a typo for infraction.

00:50:22
Speaker 1: And infarction is an obstruction of the blood supply to an organ or region of tissue, typically a thrombosis or embolists, causing local death of the tissue.

00:50:29
Speaker 2: So yes, it's also a word that, for some reason is just hilarious. It's a word like weasel or booger, infarction. It just sounds funny to me. I don't know, I know it's not funny when it kills you, but it's a funny word.

00:50:40
Speaker 1: Yes, yeah, yeah, A booger is funny when it happens to you, and infarction is not. But uh, maybe a booger's not funny depending on the context. But anyway, it makes me laugh. So you mentioned that a problem with observational studies is that you don't know what is causing the correlation. So, for example, it could be that the people who had microplastics in their plaques are people who were more likely to I don't know, get McDonald's that are in those like plastic wrappers, and you know, something about their diet resulted in them having more microplastics, and then they didn't change that aspect of their life after the surgery, and that's what led to the problems they had down the road. So it's really hard to tease apart cause and effect and you know what is causing this problem when you're looking at an observational study.

00:51:29
Speaker 2: All right, So there's lots of reasons to worry, but we don't have a great mechanistic understanding or really an idea for what problems could be caused. So what can we do? What are your prescriptions for improving our lives?

00:51:43
Speaker 1: Yeah, so I'd say that the emerging picture is that there are reasons to potentially worry.

00:51:49
Speaker 2: There's always reasons to worry, Kelly.

00:51:51
Speaker 1: There's always reasons to worry, I know. And so you can decide how concerned the information we've talked about, how concerning that is to you. But there are some things you can do in your day to day life to protect the environment. Let's start with those. So one, there are like filters that you can get that go on your laundry machine to collect some of those microfibers so that they don't go into the wastewater treatment plant and then they don't go into the ocean. You can, you know, try to buy clothes that are meant to last a little bit longer so that you're not buying as many clothes and that would result in less you know, microplastics. You could take public transportation so that you're not wearing out your own tires. There's lots of little things that you could.

00:52:30
Speaker 2: Do you can invent flying cars so I don't need tires anymore.

00:52:34
Speaker 1: Well, I think some people are working on devices to collect plastic as they get released from tires, and that seems like it could be pretty tough. You'd maybe never get all of it, but you know, you could try to work on technologies that make this stuff easier to remove from the environment. But if you're worried about your own personal risk, some things that you can do include eating from glass or metal containers instead of plastic. If you have tupperware containers, don't wash them in your dishwasher because that gets really hot it starts breaking down the plastics. Those microplastics could come off in your food. Things like vacuuming regularly are important because you're dropping plastic fibers all the time from your clothes and they end up on the floor and then they can get kicked up into the air as you're walking around. Maybe not drinking bottled water because those tend to have plastics, but there's also plastic in tapwater. But if you get a reverse osmosis filter, you can take some of it out, but those are expensive, and if you remove the microplastics, you're also removing minerals and salts and stuff, and you might want to add some of that stuff back in. A lot of this stuff is complicated, so you need to decide what are your most likely exposure risks and how concerned are you, because again there are trade offs, maybe a lot of this stuff at doses. You know, like I live in the middle of nowhere. I don't probably breathe in a lot of tire stuff. My water comes from the ground, and while groundwater does sometimes have some plastics, my groundwater where I am probably doesn't have a lot of it.

00:54:01
Speaker 2: So we should all move in with you.

00:54:02
Speaker 1: It sounds like I mean no, no, actually, because then then it wouldn't be quite as pristine. But anyway, like, I'm not too worried about my exposure to plastics because I use a lot of ceramic and stainless steel stuff, so I'm not too worried. But you know, you should think about the various ways you encounter plastic in your life and then decide if you are concerned or not, and if you want to make any changes, it's up to.

00:54:26
Speaker 2: You, And as is my habit, the night before we record, I usually ask Katrina what she thinks about an episode just to hear she has some ideas. So I asked her what she thought we could do to reduce our microplastics. And here's what she had to say.

00:54:41
Speaker 8: Well, eating fiber forms a matrix that will protect you from all toxins. Think of it like a brit of filter, where it's sucking up the toxins and preventing them from being absorbed into your body. So if you're eating fiber, then you've got this gel that sticks with you down to your colon. If there's also microplastics in your food and water, it gets sucked up into that so that it doesn't get absorbed by your intestinal cells.

00:55:08
Speaker 2: So Katrina is big on fiber, so maybe no surprise that she prescribes fiber for everybody.

00:55:13
Speaker 1: Yeah, I was going to ask if the answer to every question in the Whites and household is beans.

00:55:17
Speaker 2: Beans, She seeds beans fiber. It's good. She's just rooting for the microbes inside everybody to help with the microplastics.

00:55:26
Speaker 1: Well, we could probably all use more fiber anyway. And there are some studies in mice, for example, that find that microplastics disrupt the gut microbiome, so fiber can help you in the battle against plastics in a lot of different ways, and so, you know, I want to be clear throughout this episode. You know, I've tried to make sure I was including caveats about whether or not this is likely to be important, Like I don't want people to be freaking out. There are some reasons to be concerned, but at the moment, there's just so many different places we can encounter plastics, and so many different kinds of plastics, and so many different contingencies that matter, like where the plastic was before it got to you. That we just don't have a very good handle on this problem yet. And this is all the more reason to invest in basic science so we can try to understand this better. But like so many risks in life, you got to kind of decide for yourself, how concerned am I going to be given what we know about this.

00:56:17
Speaker 2: So don't worry too much, don't worry too little, worry just the right.

00:56:21
Speaker 1: Amount that's right, Just the right amount. Good luck with that. And the reason we talked about microplastics today is because a listener sent us an email saying I would love to know more about microplastics. So I sent this episode to them, and let's see what they had to say.

00:56:36
Speaker 9: Plastic is a wonderful material and all its different applications and all the different fields where it's an essential material. Although I don't believe that we.

00:56:49
Speaker 10: Need to be more picky how we use plastic, and we need to cut some products from our lives, especially the disposed of single use ones that are quite unnecessary. I believe I'm deeply concerned for the effect microplastics have on smaller creatures, especially.

00:57:11
Speaker 9: Ocean creatures as you mentioned in the episode, and.

00:57:15
Speaker 11: The effects that they may have on their larger food chains and ecosystems. It might sound bleak, but I'm less so concerned for the effects on human health, as we are, of course the responsible ones. But thank you Daniel and Kelly for the episode is informative. I learned some new things, and thank you for picking my suggestion.

00:57:43
Speaker 1: Thank you very much for that feedback. We did end up focusing a lot on human aspects of impacts of microplastics, but there's definitely evidence that microplastics and aquatic ecosystems are bad and impact a variety of different organisms in negative ways. So I think at a minimum, it would be important for all of us to think about how we can cut back on plastics in our lives, and we should think about what we're doing too organisms beside ourselves. So yes, thank you for making that important point.

00:58:12
Speaker 2: All right, well, thanks everyone for sending in your questions, for being curious about the nature of the world. Though we don't have a clear prescription about how you should live your life, at least now you're better informed about what we do and don't know about microplastics.

00:58:31
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