Where does this washed-up plastic come from? That's what WUR researchers want to find out. Video: Shutterstock
KENNISONLINE 2022
The Dutch coast is littered with French fries trays from beach bars, mushroom boxes from passing ships and even waste from festivals thousands of kilometres away. The new Litter ID method collaborates with involved locals to determine the origins and causes of the plastic waste that washes up. This enables a much more targeted approach to combating it.
If you pay attention while strolling along a beach or river, you will see all kinds of plastic litter, from yoghurt containers and drink cartons to ropes and pieces of fishing nets. The mix of items and the causes may differ per location, and therefore so do the solutions. But how can you get a good picture of this? And how can the relevant parties be mobilised to do something about it? These were the questions facing Wouter Jan Strietman and his colleagues at Wageningen Economic Research.
Researchers apply the Litter ID method: they take the plastic waste to a site where each category can be analysed in more detail, looking for clues to the origins. Photo: A. van den Brink
The Ocean Cleanup collects waste from the Pacific, and Strietman and his team use the Litter ID method to examine the waste. Photo: Wouter Jan Strietman
In 2017, Strietman’s multidisciplinary team headed for the Arctic Circle for the first time to survey the composition of the plastic waste washed up there using a standard method. This method distinguishes between 120 categories of waste. Even though this told them what kinds of plastic were littering the place, the researchers realised that the waste contained other valuable information too. “If you find a bottle, you can mark it in the plastic bottles category,” explains Strietman. “That will tell you that five per cent of the waste is made up of plastic bottles, for example. But you still don’t know where it came from and how it ended up in the sea. What is its story? If you know that, you can take targeted action to tackle the cause.”
Sorteren en analyseren
To get a better picture of the story behind the waste, the researchers developed the Litter-ID method in 2018. This approach supplements the standard method. Instead of making a tally of the litter at the site based on the 120 categories and then chucking it into a rubbish bag, they now take the waste to a covered location where they analyse each category in greater depth. They do this with the help of government authorities, the private sector and civil society organisations. They divide the products further into subcategories and examine the printed information on the packaging for the country of origin, brand, expiry period and other clues. Then they discuss the possible sources and causes. This helps them work out what can be done to resolve the problem.
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I came across loads of yoghurt tubs from my childhood. So they must have been around for at least 30 years
The Litter-ID method soon turned out a success. In the past few years, Strietman and his teammates have applied the method in Greenland, Spitsbergen, Scotland, Norway and the Netherlands. They also used it on campus in Wageningen for waste that was collected in the Pacific Ocean during The Ocean Cleanup.
Each area produced some surprising outcomes. “In Stellendam in Zeeland [the Netherlands], I came across loads of yoghurt tubs that were in use during my childhood. So they must have been around for at least 30 years, causing a present problem originating in the past.” Sometimes he tackles his task like a genuine Sherlock Holmes. One volunteer found a cup in Stellendam with the name of a festival on it in French. “I then searched for the festival on Google Maps. When I zoomed out, it turned out to be in Canada, not France. That was a weird discovery as it is at least 5,000 kilometres away!”
Whodunnit? That’s the core question of Wouter Jan Strietman’s research project at Wageningen University & Research. Like true detectives, they investigate waters for litter, analyse their findings, and report their conclusions on potential solutions to the plastic problem to the government and other organisations. (UK subtitles available in video)
“We saw something similar in Spitsbergen; a lot of waste there originated in Europe,” he continues. “We could deduce that from product labels and the types of product. Research from our Utrecht University colleagues showed that ‘our’ waste could arrive there in just 18 months, based on the wind and currents. We also consider the plants and animals that come with said waste and that could pose a threat to local nature. We combine a variety of different kinds of data. By looking at them in combination and by discussing the findings with local organisations, we can get the full story.”
Back to the source
The researchers found large quantities of fishing net pieces washed up in various places. Governments are trying to do something about that too. Within Litter ID, Strietman and his team also developed a method to analyse the pieces of fishing net they had found. “We always work with local fisheries experts to determine what kind of fishing is responsible for the net litter, where the nets come from and how this waste ended up in the water.”
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It is as if you are wringing out the sponge to extract information, but there are some things we can’t find out
Here too, the researchers made an interesting discovery. No one had known where the bits of net on the beach came from or why they ended up in the sea. “It turned out that most of the fishing net pieces by far were waste from repairs and maintenance. Generally speaking, repairs and maintenance are carried out on the deck of the fishing boat, so you can prevent such waste ending up in the sea by handing it in at a port rather than throwing it overboard. So that is a specific problem that you can tackle in a targeted way. And it looks like that is going to happen too. Thanks to this research, the issue is on the agenda nationally and internationally.
Getting a debate going
The idea behind Litter ID is therefore to produce a detailed analysis that reveals the origins of as much waste as possible and shows how it got there. This is not an exact science because it is partly a question of interpretation. “It is as if you are wringing out the sponge to extract as much information as possible, but there are always some things we can’t find out,” explains Strietman. What matters are the stories rather than the numbers and trends. A story can start a dialogue, as he now knows from his experience with the projects that used Litter ID.
All kinds of plastic waste wash up on Dutch beaches, such as a glove on the Wadden Sea sandbank of Griend. Photo: Wouter Jan Strietman
And a constructive dialogue is badly needed, precisely to resolve the plastic problem. “Of course you can send out a report with research results, but you can’t be sure everyone will read it,” says Strietman. “Or else different parties draw different conclusions. To prevent that from happening, we also carry out our analyses with local stakeholders: policymakers, businesspeople, local residents and nature conservationists. They help with the analysis and discuss the findings with one another. That can be the start of a conversation about solutions, because everyone uses the same information as their point of departure.”
Taking measures
With the dialogue as the starting point, the stakeholders can jointly decide on targeted measures to reduce the amount of plastic waste in the area. The chosen approach can be very different to what public authorities envisaged beforehand. Strietman: “In 2019, we visited a bay on the west coast of Greenland. That bay is a UNESCO World Heritage Site, but the banks were covered in plastic. The local authority cleared it all and started analysing the litter with our help. It turned out that nearly all the waste came from that region: people living in the town, campers, hunters and fishers. That was unexpected. Everyone assumed the waste came from far away but that was not the case. So the solution needs to focus on that particular region.”
Getting started
This spring, Strietman and his colleagues are using Litter ID to analyse waste that has washed up on the banks of the River Rotte. Rotterdam municipality wants to make the river that gave the city its name completely free of plastic. In the autumn, the team will be setting off for the southern tip of Greenland to investigate the origins and causes of the waste that washes up there, in a joint effort with WWF and local stakeholders. More locations are scheduled for 2023. Strietman: “We hope that this will let our WUR research team help tackle the global challenge of plastic soup and come up with solutions where we can.”
WHO Wouter Jan Strietman, researcher North Sea & Arctic
RESEARCH PROJECT Litter-ID
TEAM Wageningen Economic Research
Photo: Gea Hogeveen
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