Microplastics have found their way into our oceans, our food and even our brains. But the man behind landmark research into "the small stuff", Prof Richard Thompson, tells Helen Thomson he thinks a UN pact could help us clean up our act.
Richard Thompson did not plan on becoming the world’s foremost expert on microplastics. His first job involved selling tinsel, Christmas crackers and Halloween goods - exactly the kind of throwaway items that break down into the tiny microparticles he now studies. The irony is not lost on him.
It was in the 1990s, while a PhD student, that he led fellow students in a beach clean for the Marine Conservation Society, and first came across these tiny fragments of plastic pollution.
The group were using an exciting new spreadsheet program called Excel to log every item they found on beaches. Except, Thompson noticed, they weren’t recording everything.
"There was no category for the smallest debris," he says. "Most of those involved were interested in who could find the biggest item — like a trophy — and I just got really curious about the fact that the most abundant stuff on the beach was this tiny stuff we weren’t even picking up. We weren’t even logging it."
Thompson decided to ask a simple question: "What’s the smallest bit of plastic I can find?"
The answer to that question is ultimately the foundation upon which our understanding of plastic pollution is based. By 2004, Thompson was reading marine biology at the University of Plymouth and had been researching "the small stuff" for a number of years, eventually publishing a landmark study in which he first used the term "microplastics" and showed that these tiny particles and fibres were widespread in the oceans, from the seabed to the surface, accumulating in every habitat studied.
Twenty-one years later, the world has evidence of how microplastic debris has infiltrated every part of our environment and even our own bodies. No habitat, it seems, is immune: microplastics have been found as far afield as Antarctica. Estimates suggest that blue whales ingest about 10 million pieces of microplastic a day. The debris is potentially harming the ocean’s ability to capture carbon, and has recently been found in significant volumes in the human brain. Their effect on our health is still emerging, but so far, ingesting microplastics has been linked to increased fat absorption, obesity, mental health conditions and a greater risk of heart attack and stroke.
Clearly we need to make urgent changes. This past week, world leaders have been debating what those changes might look like. Delegates from 180 countries are meeting in Geneva for the final negotiation of a UN treaty to limit plastic pollution — their talks scheduled to run through much of next week. The treaty has the potential not only to reshape industry, health and the environment but our everyday life. Prof Thompson, whose work has been integral to the discussions, will be watching closely.
The most pernicious thing about microplastics are their ubiquitousness, Thompson says. Due to their characteristics — namely, being made of synthetic material, smaller than 5mm, insoluble in water and non-degradable — they are easily introduced into every environment and persist for a long time.
The main source is the breakdown of the larger plastic items that we produce in huge quantities, he says — "things like crisp packets, drink bottles. Even if we stopped producing those kinds of plastic tomorrow, we would still see an increase in microplastics because of the fragmentation of these legacy items."
Then there are the microplastics that are small by design: microbeads in cosmetics and toothpaste, for instance. From 2017 some countries began to ban the use of such microbeads, but not every country followed suit. And even where there were bans, microbeads might still be added to products such as paint, which is now thought to be a major source of leakage of microplastics into waterways.
And we continue to find new creators of microplastics, Thompson says. One current focus of his research is vehicle tyres.
"Even five years ago, we didn’t realise how much microplastic came from that source," he says. Researchers are still trying to gauge the magnitude of the problem, but he estimates that by the time you need to replace your car tyres, you will have unknowingly shed five or six kilograms of plastic dust into the environment — about enough to fill a large sports bag. Why did we miss this source for so long?
"We couldn’t see them," says Thompson. "They have a larger range of densities compared to other microplastics. They’re also black and hard to identify with current spectroscopy techniques. We’d missed them visually, so we hadn’t considered them."
Using new methods that involve heating samples to identify unique chemical signatures, researchers are finding tyre microparticles everywhere, in abundance. Thompson is particularly concerned about them.
"Tyres were never designed with the idea that they might be eaten or inhaled by living organisms," he says. "They contain chemicals that have the potential to be very toxic."
In lab tests on daphnia (small water fleas) exposure to tyre microplastic led to changes in growth, morphology and increased risk of death. Similar effects have subsequently been found in a range of other animals.
"Some of the chemicals used in tyres are of greater concern than those in other microplastics," says Thompson. "We’re not talking about hypothetical future risks, we’re seeing potential harm at concentrations that already exist in our environment."
However, we may already have a solution to the tyre problem. Consider for a moment clothes made from synthetic fibres. Between 1950 and 2016, humans around the world emitted an estimated 5.6 million tonnes of microplastic from our clothes into water and land environments. These microfibres are released when we wash or tumble dry our clothes, or even just walk around in them.
"One wasn’t designed to shed less; it was just a coincidence of the way it was designed," he says. "That tells me there’s a lot you could do at the manufacturing stage to reduce microplastic emission."
The same goes for tyres. Thompson’s collaborators found significant variation in the chemical make up across five tyre brands.
"We haven’t named the brands in our research because the chemicals weren’t included with malicious intent," he says. "The key point is that there were differences. And not all the chemicals they use were of concern, so perhaps they don’t need to be there in the design. Which are essential and which are not?"
The principle of essentiality is a theme he comes back to and may be key to turning the tide on plastic pollution at an individual and global level.
"Did anyone really miss microbeads in their cosmetic scrubs when they were banned?" he asks. "No, because they weren’t essential. We need to make sure that the plastics we produce are essential, then think about making them safer and more sustainable."
However, he warns that some seemingly more sustainable options aren’t always the answer.
"Plastic’s durability is what makes it useful. So how do you make a lemonade bottle that holds lemonade all the time you want it to, in the sun, the rain — and then the minute you no longer want it, it magically knows it’s time to self-destruct?"
In reality, a product’s rate of biodegradability will depend on the material and the conditions of the surrounding environment, and can be very slow. Biodegradable plastic can also cause a headache for recycling factories. Thompson says: "The last thing a recycler wants to see in their supply chain is a plastic with a self-destruct function."
Biodegradable products can have a place, he adds, but in closed chains — such as in food and drink containers at festivals or sports events, where the material only needs to be used for a few hours and organisers control its disposal. He says: "These products have a role, but they’re not a centre-stage solution".
Alongside smarter manufacturing and a better understanding of alternatives is international agreement on production and disposal.
In 2022 the UN established a negotiating committee tasked with developing an international, legally binding agreement to tackle plastic pollution. The fact that it has already overrun by a year is perhaps a reflection of the ambition and the friction at play.
"I hope we will reach an agreement," says Thompson of this week’s conference, "but there’s still some uncertainty."
The ideal outcome, Thompson says, is a bold, ambitious and comprehensive global agreement, signed by all 180 or so countries.
"I don’t want to say that’s shooting for the stars but it’s pitching quite high," he adds. The more realistic scenario? A smaller group of countries pushing ahead with an ambitious plan, with others joining later.
"There are between 100 and 120 countries that take this ‘higher ambition’ perspective, so we have quite a consensus already," he says.
At the last round of talks, Thompson recalls a passionate speaker from Panama standing up and issuing a plea: "He said, ‘Look, this is the time — if you don’t want to be ambitious, get out’."
It struck a chord.
"Last year I wasn’t sure we’d reach a consensus. Now it seems like people want to see decisions being made," Thompson says.
An ambitious treaty, in his view, would do three things. First, it would cap the volume of plastic being produced.
"Our ability to manage plastic waste just cannot keep up with production," he says.
One approach to this is to apply that concept of essentiality to everything we produce. Rather than trying for a hard cap on production, adopting an essential use framework to plastics — in which products have to fulfil certain requirements to be made of plastic — naturally ends up reducing production.
Second is addressing the use of the chemicals used in plastics. Of the 16,000 chemicals associated with plastic production, 4000 are known to be potentially harmful, but only a few are regulated, and many are not disclosed on products.
"Chemical composition is critical to safety — we have to cover chemicals in the treaty," Thompson says.
Third, he hopes for regulation of plastics specifically made to be small from the start, which account for more than a quarter of those escaping into the environment.
Despite the committee reaching the final stage of discussions, challenges still exist, not least in the absence of a scientific body composed of independent experts involved in the meetings, which has led to misinformation being exchanged in the corridors.
"I’ve seen some discussions where it’s like a ping pong of statements: one country saying one thing, another saying something else, and the truth lying somewhere in between," Thompson says.
While policymakers hammer out the details, the rest of us are far from powerless, he says. We must all return to the basics: reduce, reuse, recycle.
"That’s still absolutely relevant," he says, recommending using a refillable cup, avoiding single-use carrier bags, and making any number of choices every day that collectively make a difference.
"It might seem like a small individual action, but it absolutely does all add up," he says.
Thompson encourages everyone to apply the essentiality test regularly in life. Parts of your car may be plastic, which are lightweight, helping reduce fuel usage. So you might consider that essential, he says.
But is that yoghurt pot that you can’t recycle essential? What about that multi-layered crisp packet in your cupboard? Do we really need crisps to have such a long shelf life, he asks. Or could we have a slightly less durable packet that allows our crisps to be safe to eat for just a few weeks? Small acts of resilience — choosing not to buy a certain packet of crisps — from a large community sends a clear message.
"It tells producers, OK, the customer is sensitised to this issue and is acting on it."
Ultimately, whether we’re talking about an ambitious cap on global production or making different choices in the supermarket, it’s not about trying to create a world without plastic, Thompson says.
Instead, "It’s about using plastic more responsibly than we ever have before." — The Observer
