It seems like microplastics are everywhere these days — but their impacts on human health remain unclear. Today we take a closer look at why that is and how scientists are trying to get a clearer picture.
Megan Hall: Welcome to Possibly, where we take on huge problems like the future of our planet and break them down into small questions with unexpected answers. I’m Megan Hall.
It feels like there’s a new story every day about microplastics — in our blood, in our organs, even in our brains. But what does this all mean? Are microplastics bad for us? How bad? And how do we know?
Here to tell us more are reporters Will Malloy and Nat Hardy from our Possibly team
Will Malloy: Hey Megan!
Nat Hardy: Hello!
Megan Hall: To start, can you remind me what microplastics are?
Will Malloy: There are a couple of different definitions. Here’s a simple one: any plastic particles smaller than five millimeters.
Megan Hall: And how big is that?
Nat Hardy: Yeah. 5 millimeters is pretty big, about the size of a grain of rice. But these microplastics can also be tiny. So small that you can’t see them.
Megan Hall: Where do they come from?
Will Malloy: All sorts of places — a lot of cosmetic products contain microplastics, synthetic fabrics like fleece shed microplastics when you wash and wear them, car tires shed microplastics on the road. The list goes on.
Nat Hardy: And as you said, Megan, they’re everywhere.
Susanne Brander: Over the past about five to eight years or so, there have been a lot of studies in humans and we found them wherever we’ve looked.
Will Malloy: That’s Dr. Susanne Brander — she’s a professor at Oregon State University who studies how microplastics affect aquatic ecosystems.
Nat Hardy: Susanne says, even though we know microplastics are in us, we don’t necessarily know what that means for our health… yet.
Susanne Brander: A lot of what we know about humans is that they exist in our bodies. We just don’t have a full picture of what they might be doing.
Megan Hall: Why not?
Will Malloy: At the end of the day, scientists haven’t been looking at what microplastics do inside the body for very long at all.
Nat Hardy: Research on small plastics started in the 70s and 80s, but at first, scientists were just focused on studying them in the ocean and in marine animals, like fish.
Will Malloy: Scientists didn’t start looking for evidence that microplastics are in people’s bodies until about a decade ago.
Nat Hardy: In these early stages, research has been really focused on establishing that microplastics are there at all — we are only starting to study what they do to us.
Megan Hall: So does that mean we have no idea what they’re doing to us?
Nat Hardy: Not necessarily —
Susanne Brander: We have a lot of data from other animals, rodents, fish, other vertebrates, invertebrates.
Will Malloy: We call these “model species” — if we can understand how microplastics affect them, we might get some insight into how they affect us.
Nat Hardy: Scientists use model species all the time.
Susanne Brander: To understand the impacts of any kind of chemical on the human system, we often use model species to sort of mimic or better understand how that chemical is going to behave if we’re exposed to it.
Megan Hall: So, what are these studies in model species telling us?
Will Malloy: A review of studies done in rodents found a lot of health impacts associated with microplastics.
Nat Hardy: Things, like changes to their reproductive, digestive, and neurological systems.
Will Malloy: So those could be important things to pay attention to in humans.
Megan Hall: I get that we don’t know a lot yet, but when are we going to know if this is something to worry about?
Nat Hardy: That’s a really great question because it has a lot to do with how science works fundamentally.
Susanne Brander: It’s not as if one paper right is going to change the field, it’s that different scientists who are doing similar work, that that work begins to produce similar results, and that those results are in agreement with one another.
Will Malloy: As more and more people look into this, we will hopefully start to see patterns and consensus will arise as many scientists work really hard to find answers.
Nat Hardy: There’s still so much we don’t know, but Susanne says…
Susanne Brander: I do think, and others have said similarly, that we know enough to act.
Will Malloy: Reducing our exposure to microplastics probably won’t hurt us in any way, even though we don’t yet know if or how much it will help.
Megan Hall: So, how do I reduce my exposure to microplastics??
Nat Hardy: That’s a bigger topic for another episode, but the short answer is: cutting back on plastics in any way you can will help.
Will Malloy: Things that come in contact with your food are a good place to start.
Megan Hall: Got it. Thanks, Will and Nat!
That’s it for today. You can find more information, or ask a question about the way your choices affect our planet, at askpossibly.org. You can also subscribe to Possibly wherever you get your podcasts or follow us on Instagram, Facebook, LinkedIn, or Bluesky at “askpossibly”
Possibly is a co-production of Brown University’s Institute for Environment and Society, Brown’s Climate Solutions Initiative, and Ocean State Media.
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