Are microplastics really a problem?

Summary

Podcast Summary: "Are Microplastics Really a Problem?"

Search Engine Season Three, Episode: "Are Microplastics Really a Problem?"
Host: PJ Vogt
Release Date: August 15, 2025

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Introduction to the Concern

In this episode, host PJ Vogt tackles a pressing environmental and health question raised by a listener: Are microplastics really a problem? The inquiry originates from Louisa's sister, a parent deeply concerned about her twins' exposure to microplastics. This concern reflects a broader societal anxiety about the pervasive presence of microplastics in our environment and their potential impact on human health.

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Listener's Story: A Family's Worry

Louisa's sister shares her heightened anxiety over microplastics and their possible effects on her newborn twins. Her dedication manifests in stringent household practices aimed at minimizing microplastic exposure:

• Use of Glass Containers: Ensuring all condiments and materials, like water filters, are stored in glass to avoid plastic contamination.
• Organic Clothing: Dressing her children in organic bamboo and cotton to reduce exposure from synthetic fibers.
• Household Appliances: Opting for non-plastic pots and pans and employing a vacuum with a HEPA filter to capture airborne microplastics.

Despite these measures, Louisa expresses concern that excessive worry may hinder her sister's ability to care for her children effectively.

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Understanding Microplastics: Definition and Prevalence

Microplastics are defined as plastic particles less than five millimeters in diameter. They originate primarily from the breakdown of larger plastic waste, including:

• Wear and Tear of Products: Such as car tires and synthetic clothing like polyester and rayon, which shed microfibers during use and laundering.
• Consumer Goods: Items like cosmetics, paints, and detergents intentionally contain microbeads.

These particles have infiltrated various facets of life, including water sources, the air we breathe, and even the human bloodstream.

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Expert Insights: Divergent Perspectives

Professor Tracy Woodruff (University of California, San Francisco)

Professor Woodruff emphasizes the potential risks associated with microplastics based on numerous animal studies:

• Health Impacts Observed in Animals: Exposure has led to reduced fertility in male mice, increased miscarriage rates in females, metabolic disorders in offspring, and tissue damage in fish and birds.

  "When you look at animals, the doses they were exposed to caused significant health issues. It raises a concern for humans, especially considering the projection that plastic production is set to triple by 2060."
  (Woodruff, 15:18)

• Chemical Leaching: Microplastics can release endocrine disruptors and other harmful chemicals, exacerbating health problems.

• Environmental Projection: With plastic production expected to surge, the long-term implications could be devastating, potentially leading to widespread health calamities.

Professor Emily Oster (Brown University)

Conversely, Professor Oster adopts a more cautious stance, questioning the immediate relevance of microplastics to human health:

• Exposure Levels in Humans: The quantities of microplastics humans are currently exposed to are significantly lower than those used in animal studies, making it unclear if they pose a measurable health risk.

  "We don’t have direct evidence that having a lot of microplastics makes you less healthy. There's legitimate disagreement about whether at these exposure levels, there's any measurable negative effect."
  (Oster, 32:01)

• Data Interpretation: According to Oster, if microplastics were causing severe health issues, such effects would likely have been evident in population health data by now.

• Focus on Prioritization: She advises parents to prioritize more substantiated health risks over microplastics, suggesting that worries about microplastics might divert attention from more pressing concerns.

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Scientific Studies: Animal vs. Human Data

The conversation delves into the nuances of translating animal study findings to human contexts:

• Animal Studies: Research typically involves exposing animals to high doses of microplastics, resulting in observable negative health effects.

• Human Exposure: Current human exposure levels are substantially lower, and there is insufficient evidence to conclusively link microplastics to adverse health outcomes in humans.

This discrepancy leads to a debate on whether the potential risks, albeit not yet clearly demonstrated, warrant significant concern and action.

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Plastic Production and Environmental Impact

A critical segment highlights the paradoxical relationship between environmental policies and plastic production:

• Shift from Fossil Fuels to Plastics: As governments push for reduced fossil fuel usage to combat climate change, the fossil fuel industry pivots to producing more plastic as an alternative revenue stream.

  "Less reliance on fossil fuels could create a strong incentive for something most of us would agree is bad: way more plastic in our environment."
  (Oster, 35:10)

• Projected Increase: Plastic production is anticipated to triple by 2060, exacerbating the microplastic problem and environmental degradation.

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Balancing Individual Actions and Societal Solutions

The episode navigates the tension between personal efforts to reduce microplastic exposure and the need for large-scale regulatory interventions:

• Individual Measures: While actions like eliminating disposable plastic bottles can reduce personal exposure, their overall impact is limited without systemic changes.

• Societal Responsibility: Experts advocate for government policies to regulate plastic production and mitigate environmental contamination, emphasizing that individual efforts alone cannot solve the problem.

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Concluding Thoughts: Managing Worry and Prioritizing Risks

PJ Vogt reflects on the paralyzing nature of excessive worry, especially among parents. Drawing from his own experiences and understanding of the experts' views, he underscores the importance of:

• Prioritizing Concerns: Focusing on well-established health risks over uncertain threats like microplastics.

• Informed Decision-Making: Utilizing reliable data and expert guidance to manage worries constructively without letting them impede daily life.

Louisa's sister exemplifies the struggle to balance genuine concerns with practical parenting, highlighting the episode's central theme: navigating the complexities of modern environmental health anxieties with evidence-based approaches.

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Final Expert Recommendations

• Professor Tracy Woodruff: Calls for heightened governmental action to address plastic production and environmental contamination, stressing that individual efforts are insufficient to tackle the widespread issue of microplastics.

  "You want people to be concerned at the level that they are telling the government. But not so concerned that it makes them paralyzed in their individual life."
  (Oster, 50:41)

• Professor Emily Oster: Encourages parents to prioritize actionable health decisions, such as reducing plastic bottle use, while remaining cautiously optimistic about the current understanding of microplastics' impact on human health.

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Final Takeaway

"Are microplastics really a problem?" presents a balanced exploration of the current scientific landscape surrounding microplastics. While concerns are valid given their environmental persistence and presence in living organisms, the immediate implications for human health remain inconclusive. The episode advocates for a measured approach, urging listeners to stay informed, prioritize well-substantiated health risks, and support broader policy changes to address the plastic pollution crisis.

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This summary aims to encapsulate the key discussions and insights from the episode, providing a comprehensive overview for those who haven't listened to the full podcast.

Transcript

[PJ Vogt]

Hello Search Engine listeners. We are back with a new season, Season three. We have new questions and new answers for you. Our team is recharged. We are so happy to be back in the studio. As always, if you would like to support our Quixotic venture here, the best way to do it is to sign up for a premium membership at searchengine Show. We call it Incognito Mode and next week we will have a special treat for our Incognito Mode listeners next Wednesday for our premium subscribers. We're sharing my conversation this summer with podcasting superstar and infamous diva Jonathan Goldstein of Heavyweight. He dished on his rise to podcast celebrity, his many famous feuds and squabbles, all the romances and how he almost threw it all away. Just kidding. We had a fun conversation about podcasting and celebrated the return of Heavyweight. But if you want to hear that conversation, you need to sign up for Incognito Mode, our premium feed at searchengine show, before next Wednesday. Okay, enough talking about podcasts about podcasting. Let's play our podcast after these ads. This episode is brought to you in part by Vuori A New Perspective on Performance Apparel Perfect if you're sick and tired of traditional old workout gear, Vuori clothes are incredibly versatile and comfortable. Perfect for whatever your day brings. They're designed to look great beyond the gym, whether you're running errands, heading to the office or meeting up with your friends. One specific Vuori item I would recommend is the core short. This is a short that started it all for Vuori. It is one short for every sport you need for whatever sports you play. It's ideal for fitness, running and training, but also genuinely stylish and comfortable enough to just wear all day. Vuori is an investment in your happiness for search engine listeners. They are offering 20% off your first purchase. 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You can choose from a wider selection of weekly meal options, including premium seafood choices like salmon and shrimp at no extra cost. I tried Factor out. I did genuinely find it tasty, easy and nutritious. I have a promise I've made to myself, which is that I'm trying to go for a certain amount of time in my life without anyone delivering food to my house. And Factor has really helped me with my mission. Eat [e-mail] search 50 off and use code search 50 off to get 50% off plus free shipping on your first box. That's code search 50 [e-mail] for 50% off plus free shipping. Get delicious, ready to eat meals delivered with Factor. Sometimes I wonder, if I'd lived in the past, would I have made the right decisions, even if almost everyone else was making the wrong ones? I don't mean the big moral questions. I'm not talking about Germany in the 1930s. I actually just mean health questions. Like, it's the 1800s, you live in America and you're trying to decide what you can safely do to your own body. And here and there you can find these articles suggesting that a few things a lot of people routinely do are actually very dangerous. Like you can open up a newspaper and read an article claiming you ought to worry about a condition called bicycle face. This is that condition where the physical strain of riding a bike changes the shape of your face permanently into a kind of wretched grimace. Bike riding, you might read, can also damage women's fertility. Okay, honestly, knowing me, a person who likes new technology and tends to ignore scientific warnings until they reach a pretty high consensus, I jeweled for a spell. I think in the 1800s I'd probably ride bikes. I'd ride bikes, but I'd avoid the wolf peach. In the early 1800s, wolf peaches were an exotic fruit that some people enjoyed but which many people warned could be fatally poisonous. I like risk, but I'm also kind of a picky eater, so I would not have experienced the pleasure of a good summer wolf peach, a fruit which today we just call a tomato. I would have succumbed, I guess, to the tomato moral panic. So I'm one for two. Another 1800s health decision. I would have had to make cigarettes. Cigarettes had just gone from being hand rolled and so a rare, expensive luxury to very, very cheap. The automatic cigarette roller takes off at the 1880s, plunging the price to pennies per pack. There were health warnings at the fringes. A German medical student named Herman Rotman was arguing that lung tumor rates seemed to shoot up in populations after cheap cigarettes arrived. But if I'm honest, I'm almost certain I would have been a very heavy smoker. It was social, it was fun. The science was nowhere near settled in the 1800s. I ride my bike, I carefully avoid tomatoes, and I wheeze and cough a lot before dying for reasons I don't understand. But what about our present day and its new wonders and dangers? A lot of the questions we get at Search Engine come from listeners who want to know if something new is safe or not or how much they need to worry about it. And the question that sits at the top of the should I be worried about this pile? Is a question we've been getting some version of for the past two years recently from this listener. I think the first thing I should just say is hello.

[Louisa]

Hello, nice to meet you.

[PJ Vogt]

Nice to meet you. First things first. This is the same question we ask everybody. It's a very easy one. What's your name?

[Louisa's Sister]

My name is Louisa.

[PJ Vogt]

You emailed with a question you had where the question came out of your relationship with someone you identified as a relative. I don't know, maybe you want to keep them at that level of anonymity, but can you tell me about the relative?

[Louisa's Sister]

It's a very close relative. It's. It's my sister. It's my sister. I'm not that judgmental with that many people. Like, I'm just a family, know it all. So the question came out of my relationship with my sister. So we're very close family, a nuclear family. I have an older sister and a younger brother. My brother passed away about two years ago.

[PJ Vogt]

Oh, I'm so sorry.

[Louisa's Sister]

So, no, thank you. I actually, your episode on Fentanyl was, like, one of the first things I'd listened to. He passed away from fentanyl, and my dad and I listened to it together as this, like, weird looking for solutions thing, because that's just kind of family. We are. Anyways. Yeah, it was, like, really intense to, like, lose a family member and then, like, my sister, like, got pregnant with twins. And so I think everybody is on. Like, we're all just also a little bit amped up. Like, we're a bunch of neurotic Jews in a way. And you know what I'm saying?

[PJ Vogt]

Yeah. There are a lot of things. There's like grief, there's new life, there's parenthood, there's uncertainty.

[Louisa's Sister]

Like, everyone's kind of opinions, like, constant level of anxiety. That's the scoop.

[PJ Vogt]

In Louise's email to Search Engine, she'd explained how in this amped up, high anxiety family system, she'd found herself being driven somewhat mad by this one thing that her sister was doing around the kids. Hence her question.

[Louisa's Sister]

I'm actually kind of embarrassed of my question because I know exactly when I wrote it. I wrote it on an angry dog walk. And that's why there's like typos and I'm writing you are instead of your. Or your whatever. Anyways.

[PJ Vogt]

Well, was it what prompted the angry dog walk?

[Louisa's Sister]

So I was probably angry because I had either just spoken with her or spent some time with her. We were probably at her apartment hanging out with the babies, and they have this thing of, like, filtered tap water, I guess, sitting on the counter next to the sink. And like, we're in Vancouver, British Columbia. We have great tap water. And she was like, oh, no, no. Like, don't wipe their face with that water. And I was just like, what? And she's like, just, there's microplastics. And I was like, what do you mean? And she just starts going on about how, like, the clothes, she gets everything she brings in for them and this and that. She wants to prevent as many microplastics from being breathed into their lungs as possible. And that's when I was like, houston, we have a problem.

[PJ Vogt]

Microplastics, infinitesimally tiny flakes and flecks of plastic that in recent years we've learned slough off of plastic material and sometimes find their way into our bodies. One of those facts about modern life I wish I could unlearn and which actually I'm usually very good at intentionally forgetting. Not so for Louisa's sister. According to Louisa, it is the headline in her sister's brain much of the time. Can you just draw me a picture? She's afraid of microplastics. She's worrying about microplastics as like an unusually, perhaps high priority. And if I were to just walk into the house, what would I see that would tell me that they don't.

[Louisa's Sister]

Have a lot of toys, all the condiments and things are in glass. The water thing on the counter, I guess, is glass. Apparently all their clothing, like, we talked a lot about baby clothes. They have to be this, like, organic Bamboo, cotton. So there's like a hyper focus of both her and her husband on microplastics all the time. And I can see like signals between them, like, nope, not that. Da, da, da da. But I'm like, guys, the kids are in this world. They're in this world now and there's dangers everywhere. I'm worried about my sister because I'm always worried about my siblings, and I'm worried that her worry is just going to affect her too deeply and disable her to take care of these kids. Does that make sense? It's like I need her to worry less. So my question is, are microplastics really a problem? Should we be worried about our babies and microplastics and all of the things that are to be worried about bringing babies into this world? Is that the one to hyper focus on?

[PJ Vogt]

So that is Louise's question, which is really two questions, right? Pretty different ones. One is just microplastics. How much of a problem are they really? But question two is really a question about parenting. To be a parent is to purchase a lifetime subscription to worry. The risks we'd happily take for ourselves are just not the same as the risks we accept for our children. But even the most accomplished Olympic level worriers have to decide how to order their worries or outsource that decision to podcasters. After the break, we are going to take on the first of these two. What do scientists actually know right now about microplastics? That's after these microscopic advertisements. This episode of Search Engine is brought to you in part by Ollie. If your dog could talk, they'd beg for Ollie. And not just because of the drool worthy recipes. Ollie delivers more than fresh, clean meals made with human grade ingredients, they're also helping dogs live longer, healthier lives. With Ollie's On Demand health screenings, you get expert insight into your dog's diet, digestion, weight, dental and skin health. No guesswork, just peace of mind. And the best part, the screenings are free anytime for members of the Ollie app. 90% of dog parents who used Ollie's health screenings saw a positive change within 30 days. Pair that with real filler free food made in US Kitchens and you've got a wellness plan your pup will love. Head to ollie.comsearch to tell them all about your dog and use code search to get 60% off your welcome kit when you subscribe today. Plus, they offer a happiness guarantee on the first box, so if you're not completely satisfied, you'll get your money back. That's O-L-L-I-E.com search and enter code search to get 60% off your first box. This episode is brought to you in part by Constant Contact. When it comes to growing your business, we all know that engaging with your customers is crucial. But the question is always how? Most of us don't have the time, skills or money to put towards keeping up with marketing every day. We're too busy running our companies to begin with. Well, let me introduce you to Constant Contact. Your mini marketing team awaits. Constant Contact's AI Content generator helps you turn a rough idea into a ready to go message faster than ever. And with hundreds of customizable templates, it's easy to make something that looks and reads like your brand. You'll also get automated sending, real time reporting and tools that actually help drive sales. So you're not just marketing your business, you're growing it. Pricing is transparent and based on your contact list, so you're only paying for what you need, no surprises. And with a 97% email deliverability rate, your messages land far from spam. And if you ever get stuck, friendly phone support is included with every plan. Get a free 30 day trial when you go to constant contact.com try constant contact. Free for 30 days at constant contact.com constantcontact.com welcome back to the show. So plastic. Plastic may not feel to you. It didn't feel to me, particularly new, not as novel and mysterious as a fresh wolf peach. But reading about plastic's history, I was struck by how actually that's not right. In the sweep of things, plastic is new. And because it's so useful, light, flexible, sturdy, it's become ubiquitous without becoming comprehensible to us. The way wood or metal is. The story of plastic starts only about 150 years ago.

[Professor Tracy Woodruff]

The old adage has it that necessity is the mother of invention. Nowhere is this truer than in the field of plastics.

[PJ Vogt]

This is a wartime educational reel celebrating plastic. The narrator tells the origin story of this strange man made material. He explains how in 1869, human beings were trying to solve a very specific ivory shortages.

[Professor Tracy Woodruff]

Ivory, a natural product of elephant tusks, was used at that time to make billiard balls and piano keys.

[PJ Vogt]

Ivory was used back then for a lot, actually, in combs and toothbrush handles, chess pieces and dominoes. And importantly for our story, billiard balls back then were often made out of ivory. And there was a billiards craze in the 1860s. And so humans were mass slaughtering elephants in part so that other human Beings could experience the profound thrill of sinking the ball in a corner pocket were an unusual species. But billiards fans ran into a problem, which is that the high demand for ivory meant too many elephants were being slaughtered and the price for their tusks was skyrocketing.

[Professor Tracy Woodruff]

But it was growing too costly. The growing demand, the slaughter of whole herds of elephants in the long haul from the Congo to the States, all these made it necessary to find an available substitute. Now was the time to come to the aid of the grand old pachyderm.

[PJ Vogt]

And so a New York billiard ball company announced a contest, a $10,000 prize to the genius who could invent or discover some alternative material for the world's billiard balls. We had to save billiards. A man named John Wesley Hyatt decides it's going to be him. A garage inventor, Hyatt starts experimenting with different chemical combinations at home.

[Professor Tracy Woodruff]

By treating cotton letters with nitric acid, just as this chemist is doing, and then adding camphor, John Wesley Hyatt found that the resulting mixture, a gooey semi liquid substance called a resin, could be molded into permanent shape by heat and pressure. Hyatt called the new substance celluloid.

[PJ Vogt]

Celluloid, the first popular plastic, proved to be an extremely useful new material. Easy to shape, yet sturdy, water resistant, it didn't really seem to degrade over time. You could even make it in different colors. Celluloid helps open the door to a new American mass production. We begin to manufacture lots of goods, goods that are pretty cheap to produce. We love this new material. The miracle of plastic seems to be that while wood rots and metal corrodes, plastic apparently lasts forever. One obvious catch with celluloid is, is that it is unfortunately quite flammable. Two celluloid pool balls knocked together hard enough could actually explode. So while celluloid is useful, there's still demand for some kind of non flammable plastic. We invent it about 40 years later.

[Professor Tracy Woodruff]

It was not until 1907, another Roosevelt was then in the White House that a non inflammable plastic was invented by Dr. Leo Bakelep, to which he gave the name Bakelite.

[PJ Vogt]

Bakelite, even better than celluloid, cheaper, more durable, and now it doesn't catch fire. And so we're off to the races. In the decades that follow, we keep finding new chemicals to make plastics out of. These days, it's mostly petrochemicals. And our love for this material will only deepen during World War II. We use it for the liners of our Troops helmets for their goggles. We produce nylon for their parachutes, plexiglass for their warplanes. And after the war, we take our newfound muscular plastic generating capacity and flood the consumer market with cheaper goods. This is a story mostly about plastic's downsides, but I do want to briefly remind you that plastic has arguably given us more than it's taken. Plastic has not just helped us consume more cheaply, something we might feel ambivalent about. Plastic has saved millions of lives. You see a lot of plastic in hospitals. Plastic syringes, plastic IV tubes, plastic stents. The seat belts in our cars contain plastic. You need synthetic fibers since cotton degrades. Our airbags contain plastic. When it is not terrifying us, plastic can be a miracle. And for most of its time here, that was the only way we really viewed it.

[Professor Tracy Woodruff]

Modern day miracles that were made with the help of petrochemical step into the world of man made materials that take up where nature left off. This is an American city, a real community of homes and homemakers. Like thousands of others across the nation, we call it Plasticstown usa.

[PJ Vogt]

We eventually noticed that this particular miracle has an asterisk after it. In the 1960s, when the environmental movement takes flight and plastic litter becomes a concern, in the 70s, marine biologists began to document the plastic debris floating in our oceans. We realized that there is an issue. Now, the problem with plastic is that while wood rots and metal corrodes, plastic apparently lasts forever. In 2004, marine biologist Richard Thompson coins the phrase microplastics to describe the very small, sometimes microscopic, plastic fragments he and his colleagues are detecting in the oceans. Before we even knew to worry that this stuff might be in our bodies, it was the plastic in the oceans and in the bodies of fish and other sea life. There was a sign for people that something may have gone more wrong here than we'd realized.

[Professor Emily Oster]

Do you remember the famous turtle with the straw up its nose?

[PJ Vogt]

This is Professor Tracy Woodruff. She teaches at the University of California, San Francisco. She runs the program there on reproductive health and the environment. I don't remember the famous turtle with the straw up its nose. What was the famous turtle with the straw up its nose?

[Professor Emily Oster]

There's a video that went viral about a turtle that got hurt by a straw. And this led to a lot of governments, like for example in San Francisco, they banned plastic straws because it's symbolic that plastics are getting out and about into the environment and they're harming aquatic life.

[PJ Vogt]

Bless you. Have you ever heard a turtle sneeze? I have. I Went back and watched this video after my conversation with Tracy. It is very, very disturbing to watch. You know what this is? What is it?

[Professor Emily Oster]

Brain.

[PJ Vogt]

That's a worm.

[Professor Emily Oster]

Oh, that is disgusting.

[PJ Vogt]

Marine biologists are restraining a large turtle. They're using pliers to try to remove an as yet unidentifiable white thing that's lodged in his nostril. I don't know how deep, and I don't want to pull it. As they pull it out, the turtle's nose begins to bleed. He starts to sneeze and to writhe. They finally remove the object, at which point they realize what it is. It's on a freaking straw. Don't fucking tell me it's a freaking straw. A plastic straw. The notion that pieces of plastic were increasingly ending up in the bodies of sea creatures, that actually opened the door for professor Tracy Woodruff to ask whether plastic might also be ending up in human bodies.

[Professor Emily Oster]

I think it was like I was thinking, oh, plastic's in the ocean. That makes sense. And then, oh, plastics in animals. Okay, well, if there's plastics in the ocean and then there's plastics in the environment, and then there's plastics in animals, and we're an animal, oh, it makes sense that there's plastics in us. And then from there, it all. It all kind of came together and clicked. Plastics sometimes gets broken down in what are called microplastics, which is a problem we're only just beginning to understand.

[PJ Vogt]

Scientists actually started finding microplastics in our bodies very recently. The first study arrived in 2018.

[Professor Emily Oster]

Microplastics spread through the water, air, and even human bloodstream.

[Louisa]

They've been found in kidney tissue, liver tissue, placental tissue.

[Professor Emily Oster]

There was an article in the spring.

[PJ Vogt]

We're still trying to figure out what to make of all this. Besides, of course, lots of worrisome TV news segments, which is why I was talking to Professor Tracy Woodruff. So just on a super basic level, how exactly do you do microplastics get into the human body? What is happening?

[Professor Emily Oster]

Yeah, so microplastics, they're less than 5 millimeters and way smaller. So it's like the size of a pencil tip all. But they can be much smaller in range, all the way down to smaller than a virus, smaller than a red blood vessel. So you have a large range of these very small plastic particles. Some of them are intentionally manufactured, right? So they're used in the things like cosmetics, paint, laundry detergent. But the majority of them break down from single use plastic. So single use plastics include things like your Plastic water bottle. But there's also other contributors, like car tire. Wear can also contribute. Clothing is an important source of microplastic exposure. Cause clothing is made from like rayon or polyester can degrade.

[PJ Vogt]

Wait, but I never wear plastic clothes. I don't think you're saying microplastics are in some fabrics.

[Professor Emily Oster]

Yeah, like rayon, polyester. Do you wear fleece?

[PJ Vogt]

I've been known to wear a fleece.

[Professor Emily Oster]

Me too. Oh, my God. The thing that's been so interesting about doing this is like I myself am like, what? There's plastic in what?

[PJ Vogt]

Anyway, plastic is everywhere. Microplastics are too. They get into our bodies, typically through ingestion or inhalation. And even if you manage to keep a plastic free home, microplastics have their ways. You can inhale microplastics from the air, for instance, via the microplastics that have rubbed off of car tires and become tiny airborne dust. The tap water you drink can contain microplastics. They flake off people's clothes in the washing machine. They survive the trip through the water treatment plant back to your drinking supply. Learning all this, I found myself much more nervous about microplastics than I had been in the weeks before.

[Louisa]

It's gross. This definitely is not good. And this is something where it's just nobody is arguing this is good.

[PJ Vogt]

This is Professor Emily Oster. She's an economist. A lot of her research is on health and development. She's made a career helping people decide what the evidence is actually showing us. When it comes to questions about our own health and often the health for.

[Louisa]

Children, nobody's like, great idea. Consume a lot of tiny pieces of plastic to become like a bionic plastic human.

[Professor Emily Oster]

Right.

[Louisa]

Nobody thinks that. And so it's sort of our upper bound on the possible. Thing is maybe it doesn't matter. That's like the best case scenario is it's just a gross weird thing that doesn't matter. And then the worst case scenario is it is in some way damaging.

[PJ Vogt]

Emily and Tracy are going to be our guides through the science here. There have been a number of studies around microplastics. We at Search Engine have now spent a good amount of time in them. Frankly, the science does not yet seem entirely settled. A fair amount is uncertain. And so these two experts are going to help us walk through all this. They've both spent time thinking about microplastics and have ended up with slightly different conclusions, which we'll get to. But for now, what we know is that microplastics are inside of us, and. And we know that that is not optimal. But what is actually happening to our bodies once they become hosts to microplastic collections? Professor Tracy woodruff leads and collaborates on a research team that studies exposures to chemicals in plastics and how they influence our health, Particularly when it comes to pregnancy. She talked to me about how this research even works, Given you can't ethically just expose one group of people to lots of microplastics on purpose in order to study them.

[Professor Emily Oster]

When we're talking about looking at chemical exposures, for example, Typical ways that we do this in environmental health is we use animal studies, so rats and mice, where you can control their exposures and you can have a control. Basically, what we see in animals reflects what we would see in humans and.

[PJ Vogt]

In the animal studies were the animals being exposed to the chemicals in microplastics or microplastics themselves. Like, is it like you're giving a mouse water, and you're putting tiny little particles of plastic spoon in it?

[Professor Emily Oster]

So they basically purchase small microbeads. And plastics is made of different types of materials. Some of them are polystyrene, Some of them are polyvinyl chloride. So they purchase these beads, and they're microbeads, and then they put it in the water or they put it in the food, and the animals eat it.

[PJ Vogt]

So these animals are dosed with water and food that has lots and lots of plastic microbeads inside. What happens to their bodies? Nothing you'd want to happen to your body. Mice pumped full of microplastics, for instance. Males have their fertility rates drop. The females miscarry more often. Their offspring, if they have them, can have metabolic disorders. And this is not just one study or one kind of animal. Feed a honeybee microplastics, It'll lose some of its memory. In fish, microplastics can cause tissue damage. In birds, A new disease called plasticosis, where the birds suffer fibrotic scarring to their digestive tracts. Again, these are mostly animals in labs, not humans in the world. But it's concerning. Tracy Woodruff explained her hypothesis for how microplastics could be affecting human bodies. Once they get inside of us, inflammation.

[Professor Emily Oster]

They can cause your cells to react to the microplastic and attack it as a foreign body. Or they can increase immunosuppression. Because it's not just microplastics we're exposed to. We're also exposed to perfluorinated chemicals, which we know can increase health effects. We're exposed to these phthalate chemicals we're exposed to bpa. We're exposed to flame return chemicals. So we think some of the chemicals could come off of the microplastics, and then those can perturb different type of biological systems.

[PJ Vogt]

What professor Tracy Woodruff is saying here is a little complicated. She's saying that we're both trying to study how microplastic particles alone could hurt us. These tiny little fragments in our bodies wandering around, damaging our tissue, but also how the toxic chemicals inside of those fragments can hurt us once they leach out. And this is the part of the story that I most experience as the feeling of a dark forest filled with question marks. What we know is that there are chemicals in plastics that are endocrine disruptors, meaning they confuse our body's hormonal systems, which in some cases could affect people's reproductive health. We know that. And then there's been a lot of strange things happening to our bodies over the past few decades that we cannot definitively explain. Men, on average, have lower testosterone levels than they did a few decades ago. There are more adult women struggling to conceive. There are more girls entering puberty earlier. We don't know how connected these things are to environmental toxins. But a lot of scientists are looking at this, including Professor Woodruff. And scientists have noticed that sometimes, not always, but sometimes, when we compare one group of people having these health issues with a group that isn't, we'll find that the group that's struggling has more microplastics in their bodies. From professor Tracy Woodruff's perspective, we've made a big change to our environment. We're seeing changes to our health. We know that microplastics make animals really sick. And so there's a real possibility that we're all poisoning ourselves in a way that 100 years from now will seem like a real calamity. That is the scary version of the story. But I should say that that version of the story is a hypothesis. It includes some educated guesses, and it is possible for a reasonable person to look at the same studies and come to a somewhat different conclusion. Professor Emily Oster, a reasonable person, an economist who is very skilled at studying health data and assessing risk. She says, wait a minute. Let's look at all this from another perspective. She starts with the same animal studies, and at first, she sees the same things.

[Louisa]

So if you expose mice, which is our most standard animal model, to, like, very high doses of microplastics, it causes a bunch of different negative consequences in different body systems. Digestion, respiratory system, the fertility System, endocrine system.

[PJ Vogt]

But when it comes to extrapolating this to humans, Emily Oster has a good question. Do we believe that human beings are being exposed to microplastics at doses that would actually affect our health?

[Louisa]

That is the question. And that is where the evidence, I think, is not especially compelling. So the doses that humans are exposed to, even though there's a bunch of it in your brain, they are way, way lower than the doses that we're exposing animals to in these studies. And there is a fair amount of disagreement about whether those doses are, in fact, bad enough to have any, you know, measurable negative impacts on people. We don't have a lot of direct evidence or really any direct evidence that would say having a lot of microplastics makes you less healthy. So I think there's actually a legitimate disagreement about, you know, whether at the levels people are exposed to, this is actually a health problem. That would be kind of important. Like, you would want to be concerned about it for yourself.

[PJ Vogt]

When you say that, like, level disagreement, you mean, like, it's not that there's strong, clear evidence that this is definitely okay. It's just there hasn't been strong, clear evidence that it's having an effect.

[Louisa]

Yes, that's what I mean. And I would also add to that, that if the effects were very large, I think we would see them. So we're sort of in a space where I would say the disagreement is, at this level of exposure, would there be any measurable negative effect or. Or not? I think if the effects were enormously big at these low levels, those we would have already seen.

[PJ Vogt]

Emily Oster's point. And this is where she and Tracy Woodruff really do depart from each other. Emily Oster believes that if microplastics at their current levels directly caused serious health problems in humans, that would be obvious in the data. We wouldn't be wondering about it. We'd know it. And that's not what she sees. Tracy Woodruff. She's much more concerned with where we are right now with microplastics, generally with toxic chemicals in our environment. And she has questions about illnesses whose rates have increased. For instance, she suspects a possible link between rising colon cancer rates and microplastic exposure. Emily Oster says the scientists she's spoken to see alternate explanations for that rise. For instance, it could be our rising rates of obesity. But it's interesting how much we don't know. It could be obesity. It could be microplastics. It could even be the two together. Microplastics could Disrupt our digestive systems, which could contribute, along with diet and lifestyle, to obesity, all of which might spike colon cancer rates one day. We will probably know with more certainty. Today, we're still trying to reach a consensus about how dangerous microplastics are to human beings in the present moment. Oddly, our conversation about the future Is actually a lot more harmonized, since we know that microplastics can reach toxic levels in our bodies and. And that more plastic means more microplastics. We also know that we want to try to find ways to avoid increasing our global plastic consumption. Professor tracy woodruff told me, Though that is unfortunately not how things seem to.

[Professor Emily Oster]

Be shaking out right now. The projection is for plastic production to triple by 2060. So think about it. Now we know something about plastic and its impacts on our health. If we wait another 30 years to address this problem, we'll just have even more plastic, and it'll just be even harder to address.

[PJ Vogt]

Wait, we're planning to triple our plastic production in the next 35 years?

[Professor Emily Oster]

That's what the estimates are, yes.

[PJ Vogt]

And where is that coming from? Why are we making so much more plastic? Everybody gets three water bottles.

[Professor Emily Oster]

How many do you have?

[PJ Vogt]

A lot. And they're all plastic. Frankly, I like analgene, Even if it might be nuking my testostero.

[Professor Emily Oster]

So, okay, here's the thing. This is the relationship between climate change, fossil fuels, and plastic. So the fossil fuel industry has had a couple factors influence the production of fossil fuels. Now, of course, things are a little bit in flux now with the new administration, but there had been a lot of regulatory policy, Government focus on transitioning to electricity away from fossil fuel, Gas coming from the ground, away from coal, in order to address climate change. Well, once you do that right, more electric cars, more electrification of houses. Well, you're a fossil fuel company, and you've got all this fracking product coming out of the ground. You're not going to be like, oh, I guess I'm going to hang it up and go home. You're like, well, what are we going to do with all this product we have? Well, we're going to turn it into plastic. That's our new product line is plastic.

[PJ Vogt]

It's a funny paradox. The thing most of us agree is good. Less reliance on fossil fuels could create a strong incentive for something most of us would agree is bad. Way more plastic in our environment, creating much higher levels of microplastics in our lungs, our hearts, the tissues throughout our bodies. We live in a very complicated world. After a short break, we return to the question that brought us here, I ask what now feels like a relatively small how do these two experts think that Louisa, our listener, should think about her sister's anxiety around her baby's exposure to microplastics? That's after these ads. Sam this episode is brought to you in part by Robert Half need contract help for those workload peaks and backlog projects? Not alone. Robert half found that 67% of companies surveyed say they will increase their use of contract talent. That's why their recruiters leverage their experience and use award winning AI to quickly find the skilled candidates they want learn about their specialized talent in finance, accounting, technology, marketing, legal and administrative support. At Robert Half, they know talent. Visit roberthalf.com talent today.

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[PJ Vogt]

Whoa, wait. You mean finance?

[Louisa's Sister]

Yeah, finance.

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[PJ Vogt]

That's what they said.

[Louisa's Sister]

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[PJ Vogt]

Welcome back to the show. If it's okay with you, I'd like to take a moment to just talk about worry. As a human being, I worry more than most people I know. It's the first thing close friends notice about me when I get comfortable enough to show them the realer version of myself. I have a very 4k imagination for stories about about how things in my life might suddenly go wrong. I experience my own worry, often more vividly than I experience actual reality. Obviously there's a lot of downsides to that, but an upside is that I connect very easily with other worriers and I can actually be pretty calming for them since the nightmares playing in their heads are different from whatever's screening in my personal hell matinee. Which is probably why Louise's email jumped out at me. A person writing to describe how overwhelmed she was with worry. So overwhelmed it made her mad. Her worry about her sister's worries about her sister's twins identified with everyone, the new parents most of all. Parenting is such an amplifier for worry. Newborn twins I can't even imagine. Before I spoke to Emily Oster, who you heard from in the last part of the story, I spent a lot of time reading her words work. I read it because of my own worries and my project of trying to learn to live less fitfully within them. Emily is famous on some parts of the Internet for this book series and website she's built called Parent Data. It's a project with a neutral sounding name, but a very ambitious mission. Emily is very good at sifting through evidence, and she'd noticed that there was a lot of media, blog posts, articles, podcasts designed spike to parental worry, but very few public thinkers carefully just looking at the evidence, deciding which of the possible dangers to our children might be somewhat overrated or underrated. Just what did the data actually say versus what were people worried about because the conventional wisdom told them to worry about it.

[Louisa]

At some point I realized that there were things I wanted to tell parents, parents who were interested in data that were not in the books. And I thought, well, I'll start a newsletter about pregnancy and parenting, and I'll answer questions for parents like can my kid have juice?

[PJ Vogt]

How big a thing is the juice debate?

[Louisa]

People are very interested in the question of whether their kids can have juice. It used to be that people had juice. When I was a kid, people had juice. My brother exclusively drank juice. He drank so much juice, I'm surprised he's not orange. But now you're not supposed to give your kid juice. Juice is verboten.

[PJ Vogt]

And how's the evidence on the juice question?

[Louisa]

You know, the drinks your kid needs are water and milk. Your kid doesn't need juice. Juice has a lot of sugar and so people probably used to drink too much juice. But I think the current generation may be a bit too afraid of juice.

[PJ Vogt]

They've become Too juice conservative.

[Louisa]

Too juice conservative. Exactly. Too juice conservative.

[PJ Vogt]

This is where Emily Oster lives, at least online, telling you not that juice is great or that juice is evil, but instead using her expertise to help you decide how much you should turn the dial on your own juice worries how you'd like to live your life. Emily's skill is that she helps set these kinds of dials for the parents who read her across all sorts of topics. She looks at the data, she looks at the science, and she tries to answer some version of this question over and over again. Given what we actually know right now about topic X, how do we make the best possible choice about how to live in the world? Her view is that for parents in particular, there's an infinite amount of things they could worry about and they need to prioritize. And given that and given the evidence, she isn't yet convinced that microplastics should be at the top of most parents list of concerns.

[Louisa]

I don't know, I mean, I. I have a sort of a couple of different reactions. I think one is if there are any effects, they are relatively small at the levels we are exposed to. And so there are a lot of other things I would be worried about.

[Louisa's Sister]

First.

[Louisa]

I don't think we do a good enough job helping people understand, like, what are the things we really know that you shouldn't do and what are the things that are kind of like a nice to have, you know? So if someone came to me and they said, look, I'm smoking a pack of cigarettes a day and I'm drinking my water out of water bottles, I'm thinking of quitting the water bottle thing because of microplastics, I would tell them, hey, you should quit smoking first. And like, later you can worry about the water bottles. But like, the smoking is really bad. And so I think the microplastics are likely not to be for most people, very important or even the most important thing they could do to kind of improve their overall health, given where most people are. The second thing I would say is that in the kind of space of the stuff we consume, for most people, probably the one strong modifiable microplastic exposure is disposable plastic water bottles. So if someone said, I really worry about this, I want to do something about it, I would say, look, stop drinking out of disposable plastic water bottles. That's probably like the most significant thing that you can do. That is a reasonable change that wouldn't like totally upend your entire life.

[PJ Vogt]

And with your kids, do you Think about their plastic consumption. Like, do you make the small marginal edge case modifications or.

[Louisa]

No, we don't drink a lot of bottled water, but not for this reason. And I think that's actually a good point, which is that I think there is a question of, like, could we limit the amount of plastic we are introducing to the environment having nothing to do with microplastics? You know, plastic is not good for the environment. It's not good for animals in the environment. It's not good for the ocean. We produce plastic we do need, but we produce a lot of plastic we don't need. And I think it would be great if we could try to limit the amount of plastic that we consume that we don't need, even if we didn't care about microplastics at all. So in. In my own household, I guess we try not to consume a lot of water out of plastic disposable water bottles. But other than that, I don't do a lot of the other things that people ask me about. Like, for example, I will run our plastic glasses through the dishwasher. Even though many people are horrified at that idea. There's this question of, like, what is the value of worrying? Which, like, my dad, when I started thinking about this, I had written this long thing in parent aid about this, partly motivated because my dad was like, well, is this something I should worry about? And I was sort of thinking about that question, and, like, I don't like that question because the answer is almost never. You should worry about it. Like, we do worry a lot, but that's an incredibly useless way to spend our time. Really. The question you want to say is, is there something I should do about this? And the answer is, like, here's a thing you can do, but then you shouldn't spend your time worrying about it, because worrying is not a productive way to use your day.

[PJ Vogt]

It's not productive, but it's, like, not productive. So hard not to do.

[Louisa]

Totally. No. I mean, of course. That's like, the inherent thing of being a parent. You just spend your whole day worrying about your kids, and there's, like, nothing you can do about any of it, you know? How did their math test go? I hope that beach day was fun. It's just like, constantly, but it isn't productive. If you can avoid it, it's better.

[PJ Vogt]

I also took this question, how much should I worry about the microplastics in my own home, particularly with kids in the house, Back to professor Tracy Woodruff, and it was interesting when I relayed Some of the things that our listener, Louisa, had told me her sister was doing. Dressing her kids in organic cotton, only using certain pots and pans. Professor Woodruff said she thought those choices sounded reasonable. Actually, a lot like choices she makes. She's a professor who studies the toxins in our environment, and she does not put plastic in her microwave or dishwasher. She tries to wear natural fabrics like cotton and linen. She uses a vacuum with a HEPA filter. The question we often want answered from experts is just like, okay, but what do you do at your home? And the vexing thing here is that Tracy Woodruff and Emily Oster are making different choices, and both seem reasonable. Tracy does not sound to me neurotic. Emily does not sound to me reckless. They're just doing what all of us have to do when we face uncertainty, make a decision that lets us live our lives today and that we imagine we could live with tomorrow. Which left me with one last question for Professor Tracy Woodruff. In a world where microplastics are, you know, floating off the tires of the cars on the street outside my house and, you know, like, rising off my friend's fleece and into my pores or whatever, I'm curious, like, how much does it really. Does being highly scrupulous at an individual level move the needle versus, like, really, this gets solved socially?

[Professor Emily Oster]

Okay, so both things are true. You can actually lower your exposures to certain types of toxic chemicals by individual practices. That's been shown. For example, it's well established that if you eat an organic diet, you will have lower exposures to pesticides. Now, can you get rid of all of them? No. It's like air pollution. You filtered the air in your house, and that works for that. But you're not going to get rid of all the air pollution because it's also being produced by sources that you don't control. Cars, factories. But you do control it because the government can control them. I want people to be concerned at the level that they are telling the government. What they care about is that they address these toxic chemicals and plastics, but not so concerned that it makes them paralyzed in their individual life.

[PJ Vogt]

Professor Tracy Woodruff, you can find her at the University of California, San Francisco, where she researches and teaches. You can find Professor Emily Oster at Brown University or at her home on the Internet. Parent data and me. You'll be able to find me this week staring at my plastic water bottle, trying to decide whether or not I trust. Search Engine is a presentation of Odyssey. It was created by me, PJ Vogt and Truthy Pinamaneni. Garrett Graham is our senior producer. This episode was produced by Kim Kuple and fact checked by Claire Hyman. Theme, original composition and mixing by Armin Bazarian. Special thanks this week to Professor Richard Thompson and Oscar Noxon. Our Executive producer is Leah Rees Dennis. And thanks to the rest of the team at Odyssey, Rob Morandi, Craig Cox, Eric Donnelly, Colin Gaynor, Laura Curran, Josephina Francis, Kurt Courtney and Hilary Scheff. Our agent is Oren Rosenbaum at uta. If you'd like to support our show, get ad free episodes, zero reruns, and for the bonus audio that we're putting out next week, please consider signing up for Incognito Mode. You can learn more at Search Engine Show. Follow and listen to Search Engine for free on the Odysee app or wherever you get your podcasts. Thanks for listening. We'll see you next week. Sam.