Instant Genius - Solving the plastic problem

Episode Date: June 20, 2018

It’s estimated that there are currently more than 6 billion tonnes of plastic waste buried in land fill sites or floating on the surface of the ocean. Clearly something needs to be done but what exactly should we be doing? We speak to materials scientist Mark Miodownik about the growing problem of plastic waste, what we should be doing about it, and why plastic isn’t always bad for the planet. Hosted on Acast. See acast.com/privacy for more information. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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delivering digital precision with analogue warmth. So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com to learn more. The material itself is blamed for this. The blame really needs to go to all those people in the system head to two before this. And I include that all the people in the supermarkets who knew that stuff wasn't getting recycled, but they just didn't bother flagging it up and saying, do you know what, as an industry, we need to be more responsible. They just didn't do it. You're listening to the Science Focus podcast from the BBC Focus magazine team. We're the UK's best-selling science and technology monthly, available in print and in several

digital formats throughout the world. Find out more at ScienceFocus.com or look out for us in your app store. Hello and welcome to the Science Focus podcast. I'm Dan Bennett, the editor of BBC Focus magazine. It's estimated that there are currently more than 6 billion tonnes of plastic waste, buried in landfill sites or floating on the surface of the ocean. In this episode, Jason Goodyear, commissioning editor of BBC Focus magazine, speaks to materials scientist Mark Mierdovnik

about the growing problem of plastic waste. what we should be doing about it and why plastic isn't always bad for the planet. So we've all heard the horror stories in the news related to plastic waste. Whales with bellies full of plastic shopping bags, turtles strangled by drinks, can holders, great islands of plastic in the Pacific Ocean. And by recent counts there's more than 8 billion tonnes of plastic waste worldwide, apparently. So it seems recently plastics emerged as the environment's public enemy, number one in a lot of ways, but there's a lot of good things that plastic has done for us, right?

Yeah, I mean, I think the thing is that on the one hand, you look at the plastic pollution and you see it as an environmental crisis, which it is, and then you look around for answers. And the answers, I think, are not about stopping using plastic, because plastic is so integral to everything that we do. And it's integral for a reason, which is it's an amazing material. And our history of plastic goes back to the beginning of another environmental crisis, which it was invented to solve, which is that elephants were being massacred for their ivory. And plastics came along as a synthetic ivory. And that, you know, that had a huge impact. But then once people realized that it could do that, they thought, well, what else can it do?

And so, you know, molding plastic and creating bake light and then, you know, the television and reds, radio revolutions are all based around plastic. Celluloid itself, one of the early plastics, invented cinema. I mean, that's a new, you know, without, without a plastic, we don't have cinema, we don't have pretty much a lot of the visual and audio culture we have today are due to plastic. And of course, you know, comfy shoes and trainers and all these things seem like maybe superfluous, but actually, you know, plastic is just used everywhere. So the problem isn't, I think, plastic. The problem is the fact that we started to use plastic in wrapping things, which is also very good at, and then we never really thought about what to do

with those wrappings. And because those wrappings and, you know, containers don't get disposed off in the right way, they end up in the sea. So you're a material scientist by trade, which pretty much makes you the perfect person to explain to us exactly what is plastic? When we talk about plastic, what are we talking about on a chemical level? So plastics are long chain carbon molecules. So imagine carbon atoms all attached to each other in a chain, a bit like spaghetti. And imagine a bowl of spaghetti. That's what that's what most plastic looks like under the microscope. And you can change the length of spaghetti and that changes the properties. Or you can change how the individual spaghetti strands attached to each other. And that also changes the properties.

And by changing those two things, you can get this massive wealth of plastic behavior that we see around us. Everything from rubbers, the tires on your car, on your bicycle, on the planes, which are absolutely essential to all transport. That is a type of plastic. And then it's called an elastomer. And you go all the way through to the very rigid plastics that are now used to make an aircraft. So your aircraft is made from a plastic. It's called an epoxy resin. And everything in between, your pillow.

the mattresses, the sofa cushions, your trainers, and the wrapping on your tomatoes, and you buy them from the supermarket. These are all long-chain cum molecules. Yeah, so like you say, plastics everywhere these days. I only need to look around our recording studio here and I can see instantly 10 different types of plastic. But obviously, this hasn't always been the case.

And it's a relatively new invention, isn't it, plastic? We're talking about 100 years, something like that? Yeah, 100, I mean, 100 years since it was really on an industrial scale being made, about 150 where, you know, it was the early days of plastic about 150 years ago, where people were just working out the chemistry of it and working out what you could do with it. But yeah, there's a relatively new material that's coming to our lives. I think in a way that's part of the problem. If you, this has a whole new category of material before that,

metals, woods, ceramics, we'd lived with for, you know, 10,000 years. So we have, we have a very deep relationship with those materials and how to use them and what happens at the end of their lives. And metals, pretty much all metals get recycled and we have very good systems for that. Pretty much all wood either gets used for a long time or then gets burnt and anyway, it doesn't end up environmentally causing much problem, except for, of course, cutting down a forest, which is a problem. Ceramics, well, when they break, they become sand, essentially, so people don't worry about it, and they're inert.

So it's plastics coming along into our lives, changing them so much. I mean, as you say, everybody's world, the brightness of it, the comfort of it, the immediacy of it is due to plastic. we just didn't think about, well, you know, what's the life cycle? What are we going to do at the end of their life? It just didn't come up, which is a terrible thing. Do you think the sort of seed of the problem was the culture of disposability that's grown up around plastics? It's, you know, throw away plastic cups, plastic forks, plastic plates,

using things just once and then throwing them away as if it doesn't matter. But in fact, the fact that they don't biodegrade is at the root of this problem. I mean, I think, yes, I think the turning point for plastic in its history was the point where it was being used to make things that were only ever going to be used once. So it wasn't like a radio or a TV or a film or your sofa. it was a wrapping or a packaging material. And I think once we started using it for that, and it's a very good material for that,

it's inert, it's lightweight, it can be colored, people like that, it can be transparent, people like that, it protects the contents, it's not going to smash on the floor of your bathroom if you happen to drop your shampoo in the bath, all these amazing things it does for us. But then what we didn't do is say, well, okay, if we're going to make it disposable,

i.e. one use, we need to have a system for putting that material back in the system. And so-called recycling technology has come very late to the party. So what is it about plastic that makes it unable to biodegrade? It's the bonds between the spaghetti molecules, if you like, can be very strong. And there aren't many enzymes in the natural environment. What makes other things biodegrade is that there's lots of, enzymes that have evolved over millions of years to break things down because plastics are relatively new. They just haven't evolved for that material to break them down. So it's perfectly possible.

Of course, we do it in the lab, but it's not what the biological organisms out there have evolved to do. There are a few few that have been discovered recently that do do it. And of course, in the future that might increase. But of course, in a way, I think biodegradability is a distraction because what we don't really want is to biodegrade them. What we want is to, they're very valuable materials. We want to keep reusing them. Having made them in the first place, we don't want them in the sea, but we don't really want them to biodegrade.

We want to keep reusing, a bit like metals. You know, once you've got metal out of the earth's crust, like iron, steel and aluminium, you don't want it to go back to being rust again. You want it to be continually used. Sure. So a key issue then is, recycling. So when I put my, my yoghap, my plastic bottle into the recycling, what's the process

it goes through to be reused in another use? So maybe your milk bottle, which is made of high density polyethylene, you put it in the recycling. And that's an example of one that really does get recycled to a great deal in our country. It goes, it gets separated. So the first thing that happens is in the recycling plant, it gets separated. into high-density polyethylene all gets collected together, all the milk bottles. And that's done automatically by quite a clever machine that will shine an infrared light at the material and take the reflection. And the reflection is unique to that material, that plastic.

So it knows whether one thing is high-density polyethylene or low-density polyethylene, like a plastic flag, or whether it's PET, which is like a Grinx bottle, it knows the difference. and it will separate them out. So machines do that, and then once you've got all the milk bottles in one place, they're all cut up, they're washed, cleaned, because it's food grade, it's going to go back into being a milk bottle again,

so you don't want any contamination. All the bits that are not clean or can't be cleaned are separated out. All the bits that are coloured, like the tops, are separated out. And then it's re-melted, and what that means is that the strands, these spaghetti strands, are given more energy, they can move past each other, they become a liquid state.

They then are then made back into little pellets, and those little pellets are then shipped to the plastic bottle manufacturers who make another milk bottle out of it. And all that takes about three days. Okay, so you touched on that there's several different types of plastics. So can all plastics be recycled? All plastics can technically be recycled. And in fact, most of the technology is out there to be.

do it. The problem is that if you don't have a large quantity of it, it's just not economically viable to do it. So you need either a large amount of infrastructure to cope with the diversity of plastics that are out there. So about 200 plastics at the moment being used in packaging. And that requires a lot of technology to separate each one and to make that economically viable would require a huge investment. And it's currently not happening. So only a few plastics are actually recycled in this country because they're the ones that majority are used and they make economic sense. Although it's still marginal, I have to say, which is the big problem. So is there a limit to the number of times that a plastic can be recycled?

Does it slowly degrade each time? Yeah, every time you recycle it, you can imagine some of the spaghetti strands get snipped up a bit. They get damaged. They get smaller, essentially. And of course, because they're getting smaller, that changes. their properties and though that particular plastic won't be as good as it was when it was first made. So you have to take that into account and after a while you need to sort of the only way to then take it back into a usable plastic is to snip them up completely into tiny strands,

the so-called monomers of a plastic and then you chemically reconstitute it. So you do a chemical reaction to put the strands back together again. That costs energy, so that's less efficient. But it is the next step once a plastic has been so-called mechanically, you know, melted and sorted. After a while, it will then be chemically recycled. So currently in the UK, do you have a ballpark figure for the percentage of plastics that we actually do recycle? It's about 10% in reality of the amount of plastic packaging used versus the amount of packaging. that gets recycled.

Well, that's quite surprising, actually. I thought it would be significantly higher than that. I think one of the problems has been that people have been saying what they call recycling, the facts that they, or the statistics they quote, are not recycling, what they are as collection for recycling. So they say, well, we collect 50% of the plastics for recycling or 60% and we have targets from the EU to do that. But most of those plastics then get exported to other countries.

When they get exported to other countries for recycling, they aren't always recycled, but they're called recycling because we've sent them off somewhere. We then just assume they have been recycled. In reality, they haven't been recycled. So once you really look deeply at the system, you find that people are quoting figures of 50% or 60% success rates, but they aren't really true. Right, so it's not really a problem with technology, it's a problem with the infrastructure.

It's a problem with the infrastructure and investment, largely. It's also a problem of complexity because we have a very inefficient system because we use so many plastics, that the more plastics we use, the more infrastructure we need to recycle them. And that is an expensive way to behave. We could reduce the number of plastics in the system, and then you would have to do less investment to recycle those. ones. And that would make it more efficient to sort. So the reason why some people are living in certain local authorities are told very strenuously that that local authority will only take

bottles, let's say, PET, and not any other type of plastic, is because what you're doing is you're making it cheaper for that local authority to get some money out of the system. They don't want mixed plastics. You're making their lives harder and therefore it's costing them money. So obviously that's something that we need to improve on but are there are there any alternatives to recycling or plastic use like new technologies, new materials that we can use in place of plastics or even old ones like glass? I mean how does that compare on an environmental level for example? Yes, so that's a good point.

So then people, you might again use the example of milk. So we used to when I grew up, we would get delivered four pines. of milk to the door. It was very convenient for my parents and me in glass bottles. We moved away from that. And the reason we moved away from that was partly because of behavior. People were now buying their shopping in supermarkets. And they wanted to buy their milk there too, or at least the supermarkets were offering cheaper prices. And also they were, so they were packaging it in plastic because for them, packaging in plastic is about 10 times less weight. and so you use less energy to transport it.

Also, if you drop a plastic bottle on the floor, it doesn't shatter, whereas a glass one does. So you get less losses. So in the system, it was cheaper and more environmentally friendly to put milk in plastic. But only more environmentally friendly, of course, if it gets recycled. If it ends up in the city, you're obviously having an environmental damage.

So you could go back. back to glass, what you then have to say is, well, we have less pollution of the oceans, but you're going to have to pay for the transport of that glass, and it's a heavy material, and that costs you CO2 emissions. And if those CO2 emissions are not, you know, sustainable, which they currently are not, because most of the trucks are going to be diesel, then you have that environmental impact. So it's, it is a complex. It is a complex. It is a complex. a calculation to make to swap out the different materials. So another big issue that we hear a lot about at the moment is something called microplastics,

especially in the oceans and the waterways. Could you tell me a little bit about those, please? So when plastics do end up in the environment, they do get broken down, mostly mechanically at first by just being kind of bashed and pecked at and, you know, blown around. and then the light from the sun, the so-called high-frequency light, UV light, will in a sense split the bonds in between the spaghetti molecules. And so you'll get the material breaking down over time into small pieces.

And once they get to about a millimeter in size, the microplastics, and they get smaller than that too. And then they end up in the sea. because the sea is downhill from everywhere. So in the end, wind, you know, streams, bring everything into the sea. So you end up with a high concentration of microplastics in the sea, which then the fish eat, and then they're in the fish. Yeah, so I read a study recently.

I don't remember the exact figure, but there was a significant proportion of fish. The microplastics were found inside the fish, so presumably we're eating the microplastics too. Yeah, we undoubtedly are. It's in quite small concentrations. And at the moment, there's work being done to see what kind of, you know, the impact, potential impact for human health will be or is. I think the jury is out on that. Many people say that it's unlikely to be large because essentially the biggest problem

with plastic is mechanical damage inside an organism, i.e., you know, stopping its digestive system working, killing it or suffocating it, not so much its chemical impact, i.e. its interaction at a biological level with the cells in the body. But on the other hand, there are some things in plastics that have in the past been known to react with the body and to mimic hormones, for instance. And they... Right. So I think the thing is the science needs to be done on that. I think no one can say hand on their heart what they really know about the human impact yet.

Sure. So often this kind of, I don't know, a movement, I guess, they say, well, I'm going to go plastic-free, which strikes me as a very laudable aim, but very difficult to achieve. It's recently with the news has come out that even tea bags contain traces of plastic. So people have been putting them on the compost heaps or whatever, but the, there's microplastics in those. So is it realistic to live without ever using plastic, do you think? I definitely recommend people use loose leaf tea because taste better. That's backed. Well, taste better. Obviously, that's a subjective comment. But loose leaf tea is cheaper and is delicious and has it. So there are alternatives you can use. I think the tea bag manufacturers, there's no real need for them to use. What they've done and what a lot of manufacturers have done is they've used plastics to really make packaging and a tea bag is a package into a stronger item to make sure that you get the best value for your money in terms of tea in that case or tomatoes in another case or apples. If you look at the wrapping on a cucumber that you often see a polythine wrapping on a cucumber, you might think, well, that's a complete waste of plastic, but it makes that cucumber last two.

two weeks longer than one that's unwrapped. Now, food waste is a huge problem and has its own CO2 emissions that are environmentally problematic for us. So what you wouldn't want to do is to get rid of plastic packaging and then massively increase food waste because most of the plastic packaging is there for a reason. It's there to stop food waste. And so I think the danger of going plastic free is that you would actually have a much bigger problem, environmental problem, than we currently have. So what we need to do is to not have a kind of

unthought-through reaction to this problem. We've got a problem, it's a massive problem. But I think going plastic-free is not the answer. Plastic is doing a very good job at stopping food waste. What we need to do is recycle our plastic and that we have the technology for doing that. We just aren't using it and people aren't recycling their plastics because they don't think that They get recycled and they're right. So we need to change behavior, but we have to also just invest in the infrastructure. And local authorities need to do that and they need money to do that. And that's got to come from somewhere.

And my suggestion for where that money comes from is the manufacturers and supermarkets, because at the moment, they're basically offloading their profits. They get profits by having lower food waste. And they're just keeping the profits. And some of those profits need to go to the local. authorities to deal with the plastics that are ending up on their lap. Sure. So are there any, like trying to think, give our listeners a few tips to help them use plastics responsibly. I mean, are there any examples of plastic use which is a definite

no-no we should avoid? I think there's two things. One is the future is plastics where we recycle them all. And that's, that's going to take at least 10 years. So in the short, short term, I really do admire and try to do the same myself, people who are trying to get rid of unnecessary plastics in our lives, and especially any packaging that's unrecyclable. So if it's unrecyclable in the current system, we should all not use it, in my view. So things like milk bottles, well, they're very recyclable, and so I don't think any reason to stop using them. In fact, you should use them because the more of them that I use, the bigger the market and therefore the more recycled they will get. But things like throwaway coffee cups,

which are unrecyclable, they should, well, you know, they're not unrecyclable, but they're not widely recycled. Then I think cutting down on there use is a good idea and I carry around a cut with me, which also means that I have a more delicious drink when I'm on the move because I'm drinking out of glass in my case. And I think things like, you know, not using straws and all those sorts of things, plastic straws, these are all good things that everyone can do. Sure. So what would be historically, in your opinion, the most successful use of plastics that we've had? Oh, what do you define a success? I mean, you know, How has plastic helped us in the biggest way, would you say?

Is it like, for example, you were saying the food packaging, it's very, very useful? I think the other, I mean, it's so huge this category. I mean, you might say, I mean, lightweight air, you know, the reason why air travel is more environmentally friendly now is because of plastics. The reason why, you know, footwear is not using huge amounts of leather anymore. It's because of plastics. Every material has an impact on other materials. Leather as an industry has a huge environmental impact.

So you might say, well, what else should we wear on our feet? And there are clogs that you can wear in wood, and that's another option. But I think people wouldn't want to row back probably from comfortable footwear, which is brought to them via plastics, or comfortable sofas, which is brought to them via plastics. I think what people want is those plastics to be recycled and it's totally possible. It's just that we haven't invested in it. On the packaging front, what packaging has done has made food cheaper. It makes it last longer and because it makes it last longer, it's cheaper.

The infrastructure and the systems all does that for you. So what we don't want to do is get rid of plastic packaging for food. What we want to do is make it all recyclable. If we took out plastic from packaging from food, we would almost certainly walk into an environmental disaster. It's almost like plastic's been a victim of its own success. I actually wouldn't, yeah, I think the material itself is blamed for this. The blame really needs to go to all those people in the system had the two before this.

And I include that, all the people in the supermarkets who knew the stuff wasn't getting recycles. but they just didn't bother flagging it up and saying, do you know what, as an industry, we need to be more responsible. They just didn't do it. All the big brands that create all the shampoos and all the soaps and all that stuff, which is great. They all bear some responsibility for this because they all knew this. Local authorities knew this.

People just didn't prioritize it as a problem worth solving. And it took, you know, the blue planet. it and many other, you know, many other programs and journalists before that to kind of flag it up and say, do you know what, enough is enough? It's a wonderful material, but it's only wonderful if you recycle it. That was material scientist Mark Meadovnik, talking about how to tackle a growing problem of plastic waste. Thanks for listening to the Science Focus podcast. If you enjoyed this episode, then why not subscribe and leave us a review? You can find us on iTunes, ACAST, Stitcher, and many more of your favourite podcast apps.

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