How can we reduce the impact of plastic on the environment?

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Hello, you have downloaded BBC Inside Science with me, Marnie Chesterton.

This program first aired on the 10th of July, 2025.

This week, all our science stories share a connection.

The material of our era, our legacy for archaeologists from future civilisations.

It's plastic.

It's amazing stuff, but we haven't yet nailed how to not dump it all over the planet.

Major global talks on plastics are ramping up.

Could this summer be the point when the world finally agrees to take this problem seriously?

Against this backdrop, we'll be looking at plastics from the origins to ocean pollution and how science can help.

I'm joined in the studio by not one, not two, but three people with science stories you'll you'll want to hear.

Liana Hosier is a modern day Orwell, an environmental investigative journalist here to tell us about the legacy of the largest ocean plastic spill ever recorded.

Welcome, Liana.

You're going to teach us a new word.

Yes, that word is nerdle.

And if you haven't heard it before, you're going to know all about it very soon.

I'm going to tell you where it is and why it's so problematic.

Brill.

And talking of clean-ups, Mark Miadovnik, University College London Professor of Materials and Society, is here to bring us updates on a project that should help us to throw away less plastic.

Give us a clue, Mark.

Yes, this is an update from our Citizen Science project, which we launched on this programme in March.

And it's all about toilet training and reducing the number of nappies.

Cool.

And Penny Sachet is managing editor at The New Scientist and has covered plenty of plastic stories over her career.

Penny, you're here to bring us the pic of the science we need to know, so any teasers?

Yeah, I'm really excited about this potential hybrid human Neanderthal.

Excellent, we'll be hearing more on that in a bit.

But first, this week a team of Norwegian scientists have done the sort of research that you'd think would have been done already, but apparently not.

The team from Trondheim claimed to have the first comprehensive list of the chemicals contained in plastics, and it's enormous.

More than 16,000.

And more than a quarter of those are classed as chemicals of concern because of the hazards they pose to health and the environment.

The scientists say that this vast plast chem inventory can be used to help engineers make safer plastics in the future.

Here at Inside Science, it got us wondering about how plastics were even made in the first place and whether we could be doing it differently.

And so now I turn to Professor of Sustainable Chemical Engineering at the University of Sheffield on the line from Sheffield.

Rachel Rothman, hello.

Hello.

So we know that plastics are an essential part of so many aspects of our society.

You know, you don't go to the hospital without engaging in some crucial bit of plastic in some way.

So it's great.

It's light.

It's cheap.

I say it, but it's not really an it, is it?

Plastics are a suite of materials.

Exactly.

There's lots and lots of different types of plastic, and each type has different properties.

So we use them for different things.

So you get hard plastics, you get soft plastics and depending on the type of plastic makes it easier or harder to recycle when we finished using it.

And can we talk about the environmental impacts of plastics?

What do they do?

Well, there's a few different places within a plastic's life cycle that you get environmental impacts.

One is in making the plastic in the first place.

So a lot of plastics are made from oil.

You then convert that oil, you turn it into a particular type of plastic, and that processing has associated environmental impacts.

Then, we have the challenge of what happens with it at the end of its life when we've finished with it.

And that could be that it goes in a managed waste stream.

So, you put it in the bin and it gets recycled, or it goes to an incinerator, and that has an environmental impact.

And then, the other one, which is often I think the most obvious to people, is what happens when the plastic ends up where you don't want it to be.

So, when it becomes litter and it ends up in an ocean or a hedgerow, and that's often the things we see pictures of on the on the TV and things like Blue Planet.

Yes, we're going to get an update on that from Liana.

Back to these researchers in Norway, they say that a quarter of the 16,000 chemicals found in plastics are chemicals of concern.

I mean, what does that actually mean?

Well, within the paper, they have four categories that they consider to be concerning.

So one is that they could be toxic.

One is that they could be persistent.

So that means that they don't break down.

If they end up in the environment, they will just stay there and accumulate.

Another category is bioaccumulation, which is about accumulating in biospecies.

And the other is about mobility, so moving around and changing.

And so their chemical of concern could be any of those four things, or more than one of those four things in some cases.

It doesn't sound great.

It does sound concerning.

Four categories of concerning.

As a professor of sustainable chemical engineering, Are you sorting this out?

Are you developing newer, cleaner plastics?

We're working on it, yes.

And I think there's a few things to say.

One is a quarter of the plastics they found that exist, or the chemicals in plastics that exist, could be of concern.

But that doesn't mean a quarter of the total amount is of concern.

So, some of these things there may be very tiny amounts of, and sometimes things are a problem if there's a lot of it.

But if there's only a small amount of it, it may not be such a problem.

And so, within the paper that's published, they do talk about removing them if they're not needed or if they're essential for some reason.

So to give you an example, all plastics that are used in aeroplanes have a flame retardant in them.

And that flame retardant is a really important part of a plastic that you put on an aeroplane.

But that is in itself a chemical that you might need to be concerned about if it gets incinerated or reaches the end of life in some way.

So there are some...

of these chemicals that are important for the use.

And the question then is, how can we replace them with a safer alternative or how can we minimize the amount that's that's being used?

so within the research we're doing we look at how can we avoid them in the first place so can we use less then we look at can we reuse the plastic as a whole so stop them the chemicals or the plastic itself being released into the environment and we also look at different ways you could produce the plastic so instead of using oil could you make them from a bio-resource like a waste straw for example instead And which one of those are you most excited?

Which one of those do you think is going to make the biggest impact?

From an engineering perspective, the key engineering questions are around how can you make plastics from different

feedstock sources, so from different things that will have a lower impact.

However, I think the thing that will make the biggest difference overall is how we as people and society interact with those plastics.

So how do we design the system so that we use less plastic in the first place or that we reuse what we already have?

That's the thing that will make the biggest difference, just to reduce the amount of plastic there is.

And to give you an example, it's very hot at the minute.

Lots of people are taking water bottles around with them.

And we all need to be mindful in the morning.

We think, oh, I've got my reusable water bottle.

I'm going to fill it up.

We need to have places around that we can then refill it once our bottle's empty.

We need to change it from the

presumption that we can just buy a single-use throwaway bottle that may be more convenient, but is definitely not as good for the environment.

I've got Mark Miyadovnik nodding across the table and bringing him in now because, Mark, you're materials and society in your title.

Is this about changing people's attitude rather than changing the plastic itself?

I think when we say attitude, I think we mean the culture.

So

we've gone into this disposable culture where we sort of expect things to be disposable.

And that fits our lifestyles because, and it fits plastic, because it's cheap.

You can give someone which is a single-use use plastic like a bottle or even a piece of clothing these days lots of clothing is single use and 60% of that is plastic and we have we have single use shoes we have single use fans you see people going with electric fans at the moment which which will only be used probably for a couple of weeks and then thrown away and why do we think that's okay because it's that disposability to an amazing material plastic is an amazing material But if we were just to dial back our disposability,

we would then be able to cherish plastic for what it does brilliantly in things like hospitals and things like in our car.

Like you couldn't drive around without the plastic that's in tyres.

So you're going to want that.

But we don't need to carry on water in plastic.

Rachel, would you agree with what Mark just said?

100%, yes.

And I think there's...

It's not one or the other.

We need advances in the plastics.

We need to make them easier to be recycled.

We need to design thinking about what will happen when we finish with them.

But then all of us need to change our attitudes and the way we engage with plastic and the way we use it.

I'm afraid we're going to have to leave it there, but Professor Rachel Rothman, thank you so much for coming onto Inside Science.

You're welcome.

Now, we are not moving away from the topic of plastic.

We're moving on to why does all of this matter?

Well, as Rachel mentioned, when it goes wrong and plastic gets into our natural environments, it can go very wrong indeed.

So, the Express Pearl was a vast shipping container, and when it caught fire and sank off the coast of Sri Lanka in 2021, the UN called it the largest plastic spill ever recorded.

Now, four years on, Liana Hosier has been investigating the extent of the damage caused for a radio documentary and she's here in the studio to tell me more.

So what made you want to investigate?

I think ocean pollution from shipping is an issue which usually goes unreported.

There's rarely any scrutiny into the aftermath of disasters.

And so often it's out of sight, you know, out at sea and so out of mind.

But in 2021, Sri Lanka suffered one of the worst environmental disasters in its history when that massive container ship, the Express Power, caught fire and sank about nine nautical miles west of Colombo Harbour, which is the country's capital.

And as the ship burned and went down, it released a toxic cocktail into the sea.

There was oil from the ship, but also among the cargo were tons of acid, caustic soda, lead, copper, slag, lithium batteries, as well as 9,000 tonnes of epoxy resin, which is toxic to aquatic life, and over 1,600 tonnes of plastic pellets, which are called nurdles.

The UN, as you said, called it the largest plastic spill on record.

And Muditha Katuvevala is an environmentalist who helped organise hundreds of volunteers to help clean the beach along the island's western coast.

I mean, it's the biggest nerdle disaster ever recorded in the world.

Each container would have had billions of nurdles in one container and we are talking about 400 containers, estimated 400 containers.

We don't know how much was actually spilled out into the ocean but this beach was feet and feet of layers of nurdles that were washing up.

It was like snow on the beaches.

Just white everywhere.

It was horrifying.

So you've been, you've seen the nurdles.

Tell me about the environmental impacts that you found in your investigation.

What I found four years on is that Sri Lankan clean-up teams, paid for by the ship owner, are still gathering kilos of this microplastic every day.

And these nurdles, by the way, are what manufacturers use to make all sorts of plastic products.

And because they're only the size of an apple seed, Sri Lankans are literally sieving the beach by hand to try and get these plastics out.

There's research, obviously, that plastics can harm marine life, and as you were talking about, there are thousands of chemicals within plastics.

But there was another concern with these pellets because

that they might be contaminated by pollutants in the sea, which may have come from the spill or from other sources.

So working with local scientists, I sent samples of these nerdles collected over the past four years to David Megson, a forensic chemist specialising in environmental pollution at Manchester Metropolitan University.

Some of those plastic pellets were quite heavily contaminated, the ones that were involved in the fire, and they will have leached their pollution into the environment.

The plastic pellets that are still going around appear to be sucking up more pollution from the environment and are becoming more toxic.

It sounds like these tiny beads are acting like sponges.

Yes, and we're talking about them sucking up metals like lead, copper, arsenic, cadmium, and they're rising exponentially from those first samples gathered after the spill to those found now.

And these nerdles look like fish eggs so they do get eaten and they've been found in fish and bird feces.

So it's getting into the food web, which David Megson says can be harmful.

Some of those plastic pellets will be ingested by marine organisms.

They will pass pollution on.

to marine organisms but it's really hard to do that risk assessment because we we don't know how many pellets have been eaten and how much pollution comes off the pellets and what that dose is to the organism.

But placed on top of everything else that is in that system, there's a really good likelihood that it's causing harm to the environment and also potentially harm to people and humans that are eating and relying on that marine ecosystem for a source of their food as well.

So the ship owner says it worked diligently to ensure the best response while abiding by international law.

It says it's paid over $150 million million to clean up, including approximately $100 million for removing the ship and $20 million paid to the government to fund the beach clean-up and for compensation to fishermen.

But the Sri Lankan government is pursuing more money for compensation, isn't it?

Yes, there's an ongoing complex battle for compensation because this is where it gets difficult.

How do you price the long-term damage to the ecosystem and to the livelihoods and health of the people who are depending on it.

Many marine animals washed ashore dead in the aftermath, including around 400 turtles, and experts say it's more like five times that number which are estimated to have actually died out at sea.

So in the immediate aftermath of the disaster the government assembled a team of 40 scientists to assess the damage.

They put the cost at over $6 billion.

Professor Prafshanti Guniyardana is an environmental economist from the University of Sri Jai Vardhanapura and was the co-chair of that expert committee.

She explained that over half of that is down to turtle deaths.

The largest portion of this damage has been calculated for the loss of turtles.

In Sri Lanka we have very large industry to see the female turtles who are coming to lay eggs in our coastal areas.

It's a very popular tourism attracting activity among the foreigners.

There were available estimates what is the value we derive in the Sri Lankan economy per turtle.

So based on that we looked at how many turtles have died and the large turtle numbers that we are going to lose in the future according to the estimates available from our biological modeling.

So using these two figures we came up with this 4.3 billion US dollar value for the lost value of the turtles.

In response though the ship owners reject this statement and they quote ITOP, the International Tanker Owners Pollution Federation, which is an organisation specialising in assessing maritime spills funded by the shipping industry, which assessed the report and those costs as being unparticularised, inaccurate, and lacking a credible scientific basis.

Thank you, Liana Hosia, environmental journalist with Watershed Investigations.

And where can we hear your full programme?

It's on assignment on BBC Sounds, Sri Lanka, the Express Power Disaster, or on any podcast app under the documentary podcast.

And it's great.

A grim listen, but great.

Thank you.

Thank you.

I want to bring in Mark and Penny here too.

So Liana's story is a clear reminder of the damages plastic can do, especially in the oceans.

But science is coming up with more and more solutions to clean things up.

Some high-tech and some less so, right?

Well, yeah, I mean, there's been a recent report from the Royal Society really looking at all of these different options.

And I think what's really interesting to me about the report is it kind of says that beach clean-ups are actually a very good option in terms of value for money.

It brings community spirit, it changes the culture and attitudes towards plastic.

Yeah, I was quite surprised by that report because there's a suggestion that a lot of the plastic in the ocean at 80, 88%, is actually near shore.

So on the one hand, that's bad because that's where wildlife lives and it's where we like to go to the beach.

But also, it actually makes it slightly more feasible that we can actually do something about it rather than having to search the entire planet.

I'm also hearing a lot about bacteria and enzymes.

You add them to the mix and they eat the plastic.

Yeah, there's a lot of work going on that, and we're involved in a project doing that in the lab.

The thing is, you need very specific conditions for that to work, and at the moment, most of the enzymes eat the plastic very slowly.

And of course, the big push is to find suites of enzymes that will consume large different types of plastic and do it very fast.

And presumably not do the bits of undersea infrastructure that we don't want eaten, like our case.

But we're not talking about putting them into the environment.

We're talking about collecting the plastic and then digesting it with enzymes.

It's not about sprinkling them on the beach.

That will not work.

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You're listening to Inside Science with me, Marnie Chesterton.

And you can get in touch with us.

Our email address is insidescience at bbc.co.uk.

Mark, last time you were on Inside Science, you came with an idea to get us binning less plastics, specifically nappies.

And now you come bearing results.

Yes, we've got some interim results from the citizen science experiment that we're doing.

It's called the Big Toilet Project.

And what we're asking people to do who are going to toilet train their kid is to log on to our website and start to basically make a toilet training diary of when they start, what method they're using to do the toilet training, and then what their success is.

Why nappies?

Why did you pick on nappies for the project?

As a material science, they're an amazing product.

Disposable nappies are an amazing amazing product.

They do the job so well.

They have this super absorbent polymer, which is the plastic.

They don't make the baby's skin wet.

They absorb so much PMP.

It doesn't leak.

But of course, that's because of the elastomer and another plastic.

It's sealed so it doesn't get everywhere.

That's another plastic.

So they're very highly engineered.

The truth is there are 300,000 of them used per minute globally and 99% of them end up either in the environment or being burnt.

And it turns out that recycling them is difficult.

We're working on that.

It turns out that reuse, i.e., reuse Monappis, is also an option.

But the thing we really highlighted was that, hold a minute, toilet training age is just going up and up and up.

There's no reason for that because if you toilet train your kid earlier, you use less plastic, so you gain as a parent.

It's absolutely clear that it's much healthier for your kid to toilet train as early as possible, 18 months.

And so this is one of those rare cases where there's a massive plastic waste situation going on where everyone wins if you reduce it.

I'm bringing Penny Sasha in at this point as the user end of this.

Yeah, I mean, there is this narrative now that is really important to wait for signs of readiness in your child.

It kind of goes with this ethos of it's almost like baby-led weaning and gentle parenting.

It's kind of the child will show you when they're ready.

Is that not true then?

The more I've looked into it, I'm not sure.

That's a myth.

Right.

You don't need to wait for your kid to be ready in any way.

Health professionals agree on this.

Start introducing potties early and you'll have success.

So, what's your data show?

Where's the stumbling block then?

So, 62% so far of our people say they are going to wait, but they're waiting partly for readiness signs, but they're also waiting for the holidays.

So, they might even wait, delay six months, which is a long time, in order to have a bit of hot weather and some time off work.

And the other bit that we see is like 70% of our respondents so far, and we've had 2,900 people doing this experiment, they are two carer families.

So,

they're in a tough spot.

They're both working.

So if you are waiting, hello citizen scientist out there

Parent who's doing toilet training and you're thinking of doing it this summer Please log on to our website because we need your data to help the government understand this problem better Have we got time to get into how to potty train?

Is there any science to well?

That's the thing that people don't understand and I didn't either have to say as parent hold my hand up there are methods that work if you follow them you will toilet train your kid with ease in most cases.

The key thing seems to be to introduce the idea very early on, not expecting to get it early on, but to be very consistent and don't actually wait for a period of time.

So, there's this looming graph I've got in my head from Emily Oster's book.

She's an economist and she writes, she sort of applies her methods to child rearing.

And it shows that the later you start potty training, the quicker it happens.

And I remember that being a really convincing argument to leave it till sort of three-ish.

Are you expecting your data to sort of counteract that, or should we just rethink how we approach it entirely?

All the health professionals, I'm saying all of them, do not agree with that.

So by getting data in this citizen science experiment, we may be able to back that up with data, which is that actually you're much better off as a parent starting at 18 months or even earlier than waiting any time at all.

That's fascinating.

And Mark, you're taking this data to Parliament?

We are.

So

we are then going to take the results of this study to Parliament in November and we will be presenting it to MPs because this is a very urgent problem, not just in terms of pollution, but it's also a problem for schools up and down the country.

And it's, you know, the schools are struggling under the weight of the number of kids that arrive in Nappies.

We're not saying it's easy, but we're saying that we need to record everyone's struggle or ease with it so that we can present the right data to Parliament.

Thank you, Mark.

Now, Penny, we've just got time for you to bring us the latest science stories to get excited about.

And first up, I think think you're bringing us news about an AI-powered robot performing surgery?

Yes.

Well, the sort of claim is that this is an autonomous or very nearly autonomous surgery robot.

In reality, it's dissecting a dead pig.

So we can talk about whether that's really that.

The sort of motivation behind the research is: we do already have robot surgeons.

They're very closely supervised.

They're not autonomous.

And apparently, the real benefit with that is that they've sort of made various keyhole surgeries less invasive, but not necessarily have fewer complications.

And so, the team behind this say what they really wanted to do is think about a next-generation surgery robot that's actually better and more precise.

And they think they've done that.

So, what they have is it's sort of a robot with two levels of AI.

So, one level is sort of trained on how to do a gallbladder removal, coming up with the instructions about what to do next, and then the other bit of the AI is listening to its own instructions and executing them.

And so, they say that it did manage to take out a gallbladder gallbladder from a dead pig 100% accurate.

The pig wasn't, you know, breathing or bleeding, which could make it more complicated, but it wasn't fully autonomous.

And this is what I found very entertaining about this story.

It still needed someone to hand it a change of implements.

So if you think about television portrayals of surgeons, nurse, scalpel, please, I would have thought that's the kind of thing a robot could do for itself, but no.

Apparently not.

Right, thanks, Penny.

Moving on, what else?

Well, I was really excited by a story that the new scientists team covered earlier this week, which was possible evidence of a human-Neander hybrid child.

So this is a skull that was actually found nearly 100 years ago at this amazing site in Israel.

It's thought to be the oldest known graveyard.

So we're talking 140,000 years old.

And this skull has long puzzled people because whilst most of the remains there are clearly Homo sapiens humans, this skull has like hybrid or weird characteristics.

And now there's been a good analysis.

They use CT scanning and they also looked at other Neanderthal skulls, children, because this is a five-year-old.

And there's really sort of compelling evidence that this is a child that was half human, half Neanderthal, which is amazing in itself.

But also the fact that it's in this oldest grave site also raises questions about how would these populations mix?

I mean, very effectively, it sounds like.

Yeah, yeah, we do know that we interbred with Neanderthals a lot, but many of those breedings would have been sort of abortive or unsuccessful.

And this child did die at the age of five, but clearly we did do it enough that quite a lot of our DNA does come from the Neanderthals.

Fascinating stuff.

What else?

Well lastly there's been this technical breakthrough.

It's been described as a massive breakthrough that was in Nature last night about the oldest proteins ever discovered in old remains.

And so it sort of links to the Neanderthal story because we're not going to know really necessarily that that was a hybrid because we can't extract DNA from it.

They weren't able to do that.

And that's one of the really frustrating things.

Our technology with ancient DNA has come on so far the last decade or so, but it only takes us back thousands, maybe tens of thousands of years.

Now they've managed to extract proteins from relatives of elephants and rhinos from 18 million years ago, so a whole other order of magnitude.

That's five times older than we've ever managed before.

It's a bit like ancient dentistry, a tiny little drill.

They extracted some enamel from these remains, and they were able through things like mass spectrometry to actually recover protein information that was useful to kind of place it on a family tree.

And the two are linked because if the DNA is the recipe book that tells you how to make the proteins, this is basically finding the cake rather than the instructions.

Exactly, exactly.

And it can be harder looking at the cake to kind of draw conclusions, but it's still possible.

And apparently, the proteins in teeth in particular are quite variable.

And it's the variableness that really sort of holds that information.

There is this piece of DNA evidence for 180,000 years ago where they could actually tell what they were eating for dinner because that had got sort of embedded in them.

They knew they were eating duck with a kind of sort of honey accompaniment.

So it's an incredible...

You get insights into the actual life.

That's a stonky insight.

Well, thank you.

Thank you, Penny Sasha.

Thank you to all my guests, Mark Miyadovnik, Liana Hosier, Rachel Rothman, and thank you for listening.

Victoria Gill is here next week.

Catch you later.

Bye for now.

You've been listening to BBC Inside Science with me, Marnie Chesterton.

The producers were Dan Welsh and Claire Salisbury.

Technical production was by Matt Chamberlain and Never Missyrian.

The show was made in Cardiff by BBC Wales and West.

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