How do you study microplastics in a plastic-filled lab?

FLORA LICHTMAN: Hey, it’s Flora, and you’re listening to Science Friday. You have seen the headlines like, we’ve got a spoons worth of plastic in our brains, and microplastics are found in our hearts and our lymph nodes and our bloodstream. It sounds alarming, but the story might be more complicated than it seems.

It turns out that measuring microplastics is really hard to do, because guess what? We’re surrounded by plastics, including the pipettes and Petri dishes and gloves that we use in the lab. Here to tell us more about this challenge and how she’s working to get around it is Dr. Cassandra Rauert, who studies microplastics exposure at the University of Queensland in Australia. Cassie, welcome to Science Friday.

CASSANDRA RAUERT: Thank you for having me. It’s lovely to be here.

FLORA LICHTMAN: OK, tell us about this problem. Why is microplastic measurement a challenge?

CASSANDRA RAUERT: OK, so there are a lot of challenges. The problems with the microplastics analysis is that the field is so young in terms of the science is so young. So really, we’ve only been looking at plastics in the environment for roughly the last 10 years, plastics in humans for the last four years. So we’re very, very early in the technology and in the development to be able to detect them. And this is really where our research is focused is on how to overcome these challenges.

So one of the biggest challenges we have in the field is background contamination. You covered this really nicely in your introduction. There are plastics everywhere, and there are plastics everywhere in the chemistry lab. But when you are surrounded in an environment that’s full of plastic, these materials can shed particles and then they can get into the sample that you’re analyzing. So it means when we’ve been processing the sample, what we’ve done is accidentally introduced plastic into it that wasn’t there originally.

FLORA LICHTMAN: So it makes the concentrations seem higher than they actually are.

CASSANDRA RAUERT: Exactly. Yep. So what we did, the first thing we did, is we actually built from scratch a plastic free environment that we could process our samples. So we call this the Minderoo Clean Lab. It’s made completely out of stainless steel to try and avoid plastic in the paint in the walls, plastic in the lino in the flooring, plastic in the ceiling tiles. There’s plastics everywhere in construction materials. So we had to build this lab out of stainless steel.

FLORA LICHTMAN: What does it look like in there? I mean, is it very shiny? What’s the experience of being in an all stainless steel room?

CASSANDRA RAUERT: We affectionately call it the submarine, because it does feel like you’re going kind of undersea. There’s no windows except for one window where you look in. So it does feel like you’re going into this weird, enclosed space. But I like to think of it as more of what you would imagine an industrial kitchen looks like.

So everything’s stainless steel. We’ve got stainless steel shelves, we’ve got stainless steel fume cupboards, and then we’ve just got glassware sitting on the shelves. So I guess it can kind of look a little bit futuristic. Definitely very shiny. It is a big metal box, so it can get a bit noisy in there. So we have acoustic panels which are made out of aluminum. Again, metal. But yeah, it’s a massive metal box but kind of looks like an industrial kitchen, I suppose.

FLORA LICHTMAN: What about all the pipettes and Petri dishes and beakers? What do you do about those?

CASSANDRA RAUERT: Yeah, so we’ve been able to exchange everything into a glass or a stainless steel alternative. So even boxes that we carry our samples in are stainless steel. We use glass syringes instead of plastic pipettes. We’ve been able to exchange everything out. So there’s never any plastic that actually touches the sample.

FLORA LICHTMAN: Wow. I mean, it really shows you how pervasive plastic is when you go through the list of things that you’ve had to exchange out. I mean, did it change your results?

CASSANDRA RAUERT: Absolutely. So when we first commissioned the lab, we did some background testing just to see what we could detect in there compared to our normal lab where we do all of our other research. Background concentrations were 100 times lower in the clean lab, so it drastically reduces any potential for contamination.

But what’s interesting is that we still can detect some trace levels sometimes. A lot of the plastics are probably what we’re bringing into the room with us. So plastics in the air, they tend to be charged. We have this particle bubble that surrounds us, where we’ve got these static particles that just attach to our clothes. So we can actually bring them into the room with us. So we change into a fresh lab coat.

We have pull up cotton pants that we put over our clothing before we enter the clean room to try and reduce this. But there’s always some tiny particles that you still manage to bring in with you. So this just goes back to, as you said, they’re so pervasive. It’s just plastics everywhere, and that’s why background contamination is one of the biggest challenges that we have.

FLORA LICHTMAN: Given this, how do we think about previous research on microplastics? Especially microplastics in the human body.

CASSANDRA RAUERT: OK, I’m going to take a second just to think. So some of the previous studies have either not accounted for background contamination or just haven’t reported it in their studies. And I think that’s a limitation in some of the previous studies that have been published that we don’t know if they’re just reporting, say, something falling out of the air rather than an actual plastic in the sample.

But the other big problem when we’re looking at what’s in our bodies is that tissues and blood are a very complex matrix to try and analyze. They’re a very complex sample. You’ve got fats, you’ve got proteins, you’ve got carbohydrates, you’ve got blood cells. You’ve got so many different components in this sample that you need to try and remove. With our current analysis techniques that we have available to us, they’re very limited in trying to distinguish a plastic particle from these other bits in the sample.

So what our research has been showing is that, for instance, polyethylene will give you the same signal as, say, lipid or fat that’s in the sample. So that’s really where our research has been going, to try and improve analysis techniques. But I do want to reiterate the fact that this is a very new area of research in terms of understanding what’s inside our bodies. So we’re still learning. We’re still trying to improve the techniques and get the data better.

So we have started a group called the Plastics Measurements Brains Trust. And we have about 30 global researchers, all different expertise, all different fields, but all working on the theme of plastics and human health. And we come together once a year and have a big meeting and discuss how we can improve the field, how we can improve the data that’s coming out.

So we published a paper in January this year that really talked about how we can use different techniques together on the same sample to try and improve the confidence in the data. And this is really what we’re advocating for in future studies that are trying to look at plastics inside humans.

So there are things happening in the field. We’re not there yet. It’s not perfect. But I do think give us another five or so years and we will start to see improvements and more collaborations and people working together to improve the data that’s coming out as well, and hopefully have a better handle on if there’s any influence between plastics and human health.

FLORA LICHTMAN: That’s so fascinating. I mean, it’s really cool to get a window into also just to see how a new field evolves. So thank you for that.

CASSANDRA RAUERT: Yeah, this is the first time I’ve worked on a chemical of concern or an emerging chemical of concern right from the beginning. So it’s been a learning curve for me as well.

FLORA LICHTMAN: Given this, how do you personally relate to your microplastic exposure risk?

CASSANDRA RAUERT: I, in my everyday life, do put in measures to reduce the amount of plastics that I have in my home. So when I first started working in this field, actually, I changed all of my kitchen utensils. I just had cheap plastic kitchen utensils and plastic chopping boards. I just changed all of those out.

Even if we don’t have a good understanding on potential health implications from exposure to plastics, I still think it’s a good idea to be cautious about them and reduce the amount of plastics that we’re exposed to wherever you can. Plastics are not just a polymer. They’re not just a physical thing. They actually also have a lot of chemicals. We call these plastic additive chemicals. They’re chemicals like phthalates or bisphenol A that people may have heard of. And these are endocrine disruptors.

And we do have really good data on associations between exposure to these chemicals and negative health effects. So even if we don’t understand potential health effects from plastics exposure, we do that there’s a lot of negative health effects from these chemicals, like phthalates and bisphenols. So from that point of view, I think it’s a good reason to be reducing your plastics exposure, because you do then also reduce your exposure to these chemicals.

FLORA LICHTMAN: Dr. Cassandra Rauert is a research fellow studying microplastics exposure at the University of Queensland in Australia. Thanks again.

CASSANDRA RAUERT: Thank you.

FLORA LICHTMAN: This episode was produced by Rasha Aridi and Kathleen Davis. And if you’d like to increase your exposure to Science Friday, catch us tomorrow and the next day and the next day on the podcast. And then tell your friends about it, because they could probably use a teaspoon worth of Science Friday in their brains. Right? I’m taking this very far. OK, see you tomorrow. I’m Flora Lichtman.

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