TRANSCRIPT
[ASHLY] From Saint Mary’s University of Minnesota, you’re listening to Saint Mary’s Currents. I’m your host, Ashly Bissen.
[MEDIA CLIPS] Plastics take the stage. The ingenious alchemy of coal and oil provides the material. Ingenious machinery presses and stamps and molds the material into a wide variety of products. The airtight plastic containers that keep good foods fresher, longer. Wake up, America. Everything’s turning plastic. Even tape. Scotch brand plastic tape. The colored tape that’s made of plastic. With baggies, what’s good stays in, what’s bad stays out. And it’s proven scientifically. Pepsi-Cola’s new 2 -liter plastic bottle. Introducing new Aero-Wax. With 50% more plastic. It’s plastic. Fantastically elastic plastic. Plastic. Plastic. Plastic. Plastic. Plastic. Plastic. Plastic. Plastic.
[ASHLY] From the cars we drive to the prepackaged food we eat, the use of plastics in consumers’ lives every day only continues to grow.
[MEDIA CLIP] The United States produces more plastic waste than any other country in the world. Hundreds of tons per person. About 90 % of it ends up in landfills, is burned or shipped overseas.
[ASHLY] It’s showing up on our beaches and in our parks.
[MEDIA CLIP] A large amount of that waste ends up degrading into microplastics, small particles that linger in our environment and can be consumed by animals and people.
[ASHLY] But what about the plastics we can’t see or can barely touch? These tiny particles are turning up everywhere, from the deepest parts of the ocean to the food on our plates and even inside our bodies.
[MEDIA CLIP] As plastic degrades, it doesn’t just disappear. It breaks into tiny pieces. It ends up in the dust in our homes and in rivers and lakes and oceans. It also goes up into the sky.
[ASHLY] The scale of micro- and nanoplastic pollution has sparked serious questions about our health, our environment, and our future. According to a recent article from the New York Times, scientists say it could be years before we have a full understanding of how microplastics and nanoplastics are affecting human health. So what are these particles and where are they coming from? And what are the real-world consequences of their widespread presence on the environment and our health?
Dr. Pfaff, thank you so much for joining us today. Before we dive into this topic, can you introduce yourself to our listeners and let them know what you do here at Saint Mary’s, your professional background, and what your academic interests are?
[PETER] Certainly. Thanks for having me. So I’m a professor of biology at Saint Mary’s. I’ve been here for just over two years. And my background is in aquatic ecology. And so really anything related to aquatic ecosystems, I’m a huge fan of, whether it’s fish or the little bugs, the macroinvertebrates and the trout streams and even water quality. Especially up here in Minnesota, there’s a big focus on things like the harmful algal blooms and all of that. And so I’ve done quite a bit of research with that in the past.
[ASHLY] Now, our topic today is really about micro and nanoplastics. Can you explain what microplastics and nanoplastics are and how are they different from each other?
[PETER] So when it comes to micro and nanoplastics, the big difference comes down to their size. So there’s a continuum of sizes as things break down from the larger macro or mesoplastics. Those are the kind of things that you would be able to see with your hands, you know, pick up out of the water. larger bottles or bottle caps, things like that. And then once you get down to really, really small particles, almost things that you can’t touch, so about a half a millimeter or so, this is when you’re getting into the range of the microplastics. And those will get all the way down until you get to nanometers. So at about a thousand nanometers, this is a fraction of the width of a human hair. Then you get into the range of nanoplastics. So we’re really talking about things that are difficult to do. Detect, to be honest, in the environment. Now, one other important category of differentiation for micro and nanoplastics is they also come in primary and secondary. Primary are when they’re manufactured to be that size for some purpose. Secondary are when they get to that size through breakdown. And those two categories can have pretty big differences in how they interact with the environment.
[ASHLY] Do you get some of those breakdowns? I mean, obviously, we’re dealing with, you know, recycling as a process, is that one of the ways that that breakdown can occur beyond just time and other elements?
[PETER] Certainly, yeah. So anytime you’re working or processing plastic, you’re going to be releasing small particles of it. Now, with that being said, any kind of recycling where you’re taking larger, those macroplastics out of the environment before they break down. That’s a good thing. When you have a bottle that completely breaks down in the ecosystem into those micro or nanoplastics, that’s when you can start to have a huge amount of, you know, the smaller materials.
[ASHLY] Gotcha. So,The New York Times reported that microplastics have been found from the depths of the Mariana Trench to heights of Mount Everest. And we know that plastic is accumulating in our bodies too. And obviously this sounds extremely concerning. So can you explain where these tiny plastics are coming from? What are some common main sources where we may find them in our daily lives?
[PETER] Yeah, certainly. So a lot of the plastics that we see in the environment now are going to be those secondary plastics. So things that have broken down. from larger materials. Thankfully, a lot of the primary ones, they used to be common in things like skincare for exfoliators, things like that. Most of those have now been banned in the U.S., Europe, and a lot of places. Two really big sources of secondary plastics seem to be from tires, so tire wear, and then textiles. So all of our clothing, every time you wash it, you’re kind of breaking off these really tiny little pieces, and those go directly into the micro and nanoplastics. And then, of course, driving, you know, you think about your tires, you’re gradually wearing down. Well, those are tiny little pieces that are coming off of there. So over the course of a tire’s lifetime, 60, 70, 80 1,000 miles, you’re losing, oh, what … half a centimeter — close to a centimeter of tread? And that’s all just going onto the road where it’s getting washed into the ecosystem or straight up into the atmosphere.
[ASHLY] That’s really interesting. I mean, I’ve heard about it in clothes before, but tires is not a source that I would have automatically thought that micro or nanoplastics would be showing up. So that’s interesting.
[PETER] That’s something that’s been really kind of a big focus recently, where it may be actually the largest source that we see of these within the environment.
[ASHLY] So what are some of the most concerning environmental effects of micro and nanoplastics?
[PETER] So when you start to get to really small sizes, things work a little bit differently. And really, it just comes down to how reactive they are in the environment. So reactivity is based on the surface area of an object, right? So how much area it has to interact with the environment. So if I had like a one centimeter by one centimeter by one centimeter cube of tire or plastic, that would mean we have six. square centimeters of surface area, right? So if I half that particle size, so three dimensions, I have to chop it three times. So then I would have eight half centimeter sized cubes. So what does that do to the surface area?
[ASHLY] I assume it would get larger.
[PETER] It doubles it, actually! And so you have the same amount of material, but instead of six square centimeters, you have 12 square centimeters. So if you keep chopping all of those up, once you get down into the microplastic range, you’ve taken this one little centimeter cube of plastic and you’ve increased its surface area to over a square meter. And then at nanoparticle sizes, that can get even, yeah, even larger surface area. And so all of this area is going to be interacting with different parts of the environment. And what that means is especially the materials within those plastics can have a chance to leach out. And so some of the really common chemicals that have been talked about recently, phthalates, phenols, and formaldehyde, those seem to be some of the larger ones or the more detrimental ones to the environment. And then also the plastic particles themselves, a lot of animals will eat them or ingest them, especially things that are in the water, and those can start to accumulate within the bodies. I think one really kind of poignant image of that is sometimes you can see pictures of seabirds, especially albatrosses, where they have a skeleton and feathers. Their body cavity is just filled with, in this case, you know, those larger like macroplastics. But the same thing happens on the smaller scale with things like plankton or other aquatic organisms.
[ASHLY] And now on that note, according to the National Library of Medicine, the average human is consuming around 39,000 to 52,000 particles of microplastics per year. And then you factor in inhalation of particles as well. Obviously, that figure is increasing. We’re looking at more like 74,000 to 121,000. So how are these plastics ending up in the food that we eat and the water that we drink? And how widespread do you think this exposure is?
[PETER] Yeah, so one interesting thing to note — so that study from the National Library of Medicine, that was from 2019, they recognize that those probably are really big underestimates. And also, that’s only microplastics. That’s not even counting nanoplastics, which are, you know. 10 … 100 times more prevalent within the environment. And so, yeah, there’s just a lot of them. And when it comes to how we’re being exposed, the earth is just completely inoculated at this point. And so all these plastics that have broken down, especially they’re getting washed downstream in the water, those will end up in the soil. You’re growing plants and other things, and those are coming up. And so all the food is already going to have some of these particles on them. And then another difference point is when we’re eating organisms, meat or other things, right, they have a chance to start bioaccumulating and magnifying the amount of those micro or nanoplastics. And we can be taking in even a larger amount. And that seems to be most common in seafood, I think. At least that’s where the most studies have occurred.
[ASHLY] Now, do you also think, too, we talked a little bit about that study being in 2019 — obviously, it’s 2025 now. Do you think that there’s a drastic increase in those numbers in that time frame? Or do you think that there’s any initiatives that we’ve taken to help keep that level relatively comparable or have lowered at all?
[PETER] Yeah, so. It’s most likely that the level of micro or nanoplastics within the environment is kind of proportional to the amount of plastic being created each year. And since the inception of plastic, we’ve been increasing our amount of plastic production. And it is essentially exponential. So, yeah, it’s very unlikely that that number would have gone down at all, which is a bit unfortunate. The flip side of that is more and more places are becoming aware of how to deal with plastics and especially things like the single-use plastics, which are most likely to end up in landfills and things like that. If legislation is able to start minimizing those, that can certainly reduce our exposure, especially to things in our immediate vicinity.
[ASHLY] Typically, when I’m shopping for groceries, you also have to factor that into an account. Most of what we purchase ends up in plastic, is wrapped in plastic. What kind of impact does that have even when we’re looking at what we’re eating and drinking?
[PETER] Yeah, absolutely a huge impact, right? So anytime your food is in proximity or in contact with plastics, there’s the chance that some of those have, you know, micro nanoplastics on them or those are breaking down in order to directly get on. into contact with the food, especially when things have been, you know, packaged for a long time, have a long shelf life, and even things that you might not consider to be plastic. For example, canned foods. Those have, you know, a plastic liner inside of them. So really, yeah, everything that we’re purchasing and, you know, the next stage of that, we bring all that food home, we chop it up, we cook our meal, and then we might, yeah, store it in plastic, put our plastic wrap over the top of it. And even chopping it up, if you’re using a plastic cutting board, all of those cuts are chopping up and dicing little pieces of plastic which end up in the kitchen, maybe on the food as well. And a lot of times, those larger plastics, if we’re eating them, they’re going to be passed through our body. But there’s always going to be some that are going to stick around. They’re going to find their way into an area or, you know, those nanoplastics into our bloodstream. And then that’s where it can become more challenging because then it can build up in tissue that’s not necessarily able to get rid of that easily.
[ASHLY] Now, in a CNN article from earlier this year, a doctor from the University of New Mexico mentioned that 45 to 50-year-old cadavers they were studying had the equivalent of a standard plastic spoon amount of plastic in their brains. He went on to say that it’s about 50 % higher than a study they did in 2016. What does the current research say about the potential health risks? I mean, if we continue to see doubling of plastic in our brains every 10 years, where does that leave us? And what does the current research say about the potential health risks for humans?
[PETER] Yeah, that’s kind of a shocking result and just the idea that there’s that much plastic within us. And especially in the brain, crossing the blood-brain barrier is no joke. And especially these smaller nanoplastics, those are the ones that can accumulate. And I guess the good news of all of this or the maybe not “as bad” part, is that plastic is largely it’s not directly damaging us. It’s not toxic in and of itself. But the difficulty, again, is those chemicals that are leaching out. And so I mentioned before things like phthalates — so those are endocrine disruptors. They’re altering the way that our hormones are working. A little more scary would be like formaldehyde. And that works by forming these cross-linkages between amines. And so essentially, it can denature proteins, and that’s one of the things that can lead to negative impacts within your body, higher rates of cancer, things like that.
Now, the difficulty with these kinds of studies though, where you’re looking at health risks — you’re kind of comparing it against a previous period of time when a lot of things have changed and it’s a little sad because there’s no control group right we’re all inundated with these plastics and so we’re kind of just seeing how our bodies or how things are changing over time, rather than being able to compare them really nicely in, you know, a laboratory study. But there are a lot of groups that are trying to kind of disentangle this. And especially within the EU, they have a lot of studies looking at different demographics, those with a regular background exposure versus, for example, those people who are working really close proximity to these microplastics, such as in textile manufacturing or things like that. And as far as I know, a lot of those studies are still ongoing, so I’m not familiar with any results. But there are actually quite a lot of manipulative laboratory studies using zebrafish, and especially zebrafish larvae, looking at different levels of plastics. And a lot of them will affect the endocrine system. They can affect the speed and development of these embryos.
One of the bigger things that it seems to impact is the immune system, right? So it’s causing some immune responses, maybe suppressing other immune responses, and anything like that might, you know, lead to increased amount of illness or other things like Alzheimer’s — chronic diseases, right? Especially relating to the immune system.
[ASHLY] I would be really interested to see over time, because I mean, you indicated there isn’t a control group, but studies like this take a long time too to really determine anything. So how much of this is going to be information that we’re not really going to know about for the next 50 years even?
[PETER] Exactly. Yeah. And that is always a difficult thing when, you know, you make these materials and we live in close proximity to them and then you start to think oh well now we need to know a little bit more about it right and there’s a long history of that taking place, you know, think back to the 1920s, the big wonder thing was leaded gasoline, right? And then after that, we had different refrigerants, DDT. And then, of course, now we’re discovering more about PFAS and some of the other forever chemicals that are really impacting the environment. And so there’s always seems to be a lag of, you know, we’ve been exposed to these things for a long time. And then only later do we really find out the full impacts of them.
Now, as far as the plastics go, the other, I guess, bad news about it is it seems like the longer that they’re in the environment, actually, the more toxic they can become because they become further degraded. And so it’s likely over time, even if we keep plastic waste at a constant level, it might become more impactful, at least in the immediate future. But hopefully over time, there can be some ways that we can mitigate it.
[ASHLY] We’ll be right back in a minute.
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[ASHLY] So are there any promising technologies or approaches to removing microplastics from the environment?
[PETER] It’s, again, really difficult to even identify them within the environment, let alone remove them. I think that the biggest strides and really very positive things have been in removing the macroplastics from the environment, right? So before they get to that stage. So one huge success story is the Ocean Cleanup Project that’s been over the last several years now tackling the Great Pacific Garbage Patch. And they’ve made huge strides in removing just a massive amount of plastic from the ecosystem. And the more people that, you know, focus on reducing their plastic usage, increasing recycling, having government-led initiatives, you know, more places that are doing recycling like we do here in Winona, all of those things can be — especially in the future, by preventing those microplastics or nanoplastics from entering the environment.
[ASHLY] So how can individuals and communities reduce their own plastic footprint or support additional solutions?
[PETER] Yeah, so when it comes to… plastic, and really any environmental impacts that are caused by our consumption. Or within conservation biology, we talk about affluence, the amount of resources that we consume, the amount of energy that we use, all of those kind of things. So reducing or minimizing an increase in our affluence is really the biggest way that we can start to mitigate these issues within the environment. And not only does that go for plastic footprints, but you know, your carbon footprint, all of these other kind of things. And so long distance transport, driving, right? We talked about tires being a huge source of it. And so seeking out ways to either reduce the amount that you’re driving or alternative ways of moving around, doing more biking, more walking, public transport, which some areas is easier than others, right? But that can make a really big difference. Then be conscious about purchasing more natural fibers rather than synthetic fibers can make a big difference. Minimizing your own use of single-use plastics and supporting other legislation or promoting use of paper bags or reusable canvas bags, things like that, rather than plastic bags or other things that are more likely to end up in the environment, more likely to end up not recycled. So those are the things that you know, as individuals we can do in order to help mitigate this problem again, not right now, but in the future, right? If we do those things now, then it can create a better environment, a better ecosystem for the next generation, which is, yeah, would be great to do.
[ASHLY] It’s interesting for me to think about, you know, because I’ve done my own steps as far as trying to use plastic less where I can. I don’t travel often, but when I do, I am the type that if I’m on a beach and I see a piece of plastic, I am picking it up. I’ve always thought of that as being helpful from that macroplastic stance of the, hey, I don’t want this to end up inside a bird’s belly later. It’s interesting to have that kind of reconcile with the effect that it would have on reducing the footprint from a microplastics and nanoplastics stance. So that’s not something I’ve ever considered before. Double effective — I’ll take it!
[PETER] Yeah, absolutely. Right. You’re preventing a future detriment to the environment, which is really great. Right. And ultimately, like you said, if everybody was as proactive of, you know, looking out and trying to help out the environment, especially in their immediate area, then that can just have huge benefits for everybody.
[ASHLY] So what gives you hope when it comes to addressing this issue? Are there any promising trends or developments that you’re watching?
[PETER] So, it’s a little bit difficult answering this question because there doesn’t seem to be an immediate, you know, step to take in order to help the problem right now. Like I said, a lot of times I see people moving in the right direction of trying to be more conscious about their use of plastics or, you know, watching out for others removing plastics from the environment, things like that. The thing that gives me a little hope, at least, is that plastics have been around amd well, we’re still alive right? You know, life expectancy is pretty good. And so it’s not an immediate danger like things in the past, like leaded gasoline or some of these other things that have had really dire health consequences. But with that being said, of course, it is still a big health consequence. And so hopefully there will be some other ways in order to, you know, mitigate the amount of microplastics within the environment or at least the human health impacts. I think that the really big thing that we need to do and hopefully will continue happening is just research into exactly what’s going on with these.
I talked way back at the beginning a little bit about other nanomaterials — things like titanium dioxide or nanosilver, things like this, like those types of compounds seem to be a little bit more reactive. And so plastic may be not quite in the same ballpark as that, but still living in such close proximity, it’s something that knowing anything about, doing more research in order to understand the impacts can go a long way in order to understanding it and mitigating the human health and environmental impacts going on into the future.
Now, another thing that is kind of promising and not something that we’re doing, but something that nature is doing, there are some bacteria that have been discovered pretty recently that have some novel path. pathways kind of using enzymes or proteins that previously were used for other things, but have formed into a new pathway that are breaking down nylon within the environment. And so there’s been a lot of study on these recently. So this kind of novel mutation and adaptation in order for these bacteria to start utilizing a new energy source, which is awesome. I wish it was something that we could do more readily, but of course, bacteria and nature, they have a huge arsenal of pathways in order to metabolize compounds in the environment. And so hopefully if more pathways or these bacteria are able to start breaking down the nanoplastics they’re coming into contact with, then that could be a huge benefit to everyone in the future.
[ASHLY] It’d be a really nice potential for reducing if that’s something that can be harnessed in the future.
[PETER] Absolutely, yeah. And there’s a lot of groups that have used those types of bacteria for other purposes, for example, oil spills. So once people put up buoys to contain those oil spills, but then bacteria do the on-the-ground work, they’ve been mostly natural, but taking those, inoculating those areas with these bacteria, and they’re breaking down the oil on top of the water in order to metabolize it and reduce it. from the environment. So yeah, this type of strategy has been used in other areas to really good effect.
[ASHLY] Well, I think you’ve given our listeners a lot to think about. I really appreciate you taking the time to chat with me today.
[PETER] Yeah, absolutely.
Saint Mary’s Currents is a production of the Saint Mary’s University of Minnesota Office of Marketing and Communication. It is produced by Ashly Bissen with help from Michelle Rovang. It is recorded, edited, and engineered by Geoffrey DeMarsh. Our theme music is by Will van de Crommert. For more information on this episode or Saint Mary’s Currents, visit smumn.edu/currents. And if you enjoyed this episode, please follow us wherever you find your podcasts. I’m Ashly Bissen. We’ll see you next time for Saint Mary’s Currents.
