Europe’s Lifeline a Floating Rubbish Dump: ’Grotesque’
It is well known that large amounts of rubbish float through Europe’s rivers. But when researchers took a closer look at one of the continent’s most important waterways, they made an unexpected discovery – the problem is much bigger than previously thought.
The rubbish in the river is collected in a barge, where it is gathered in baskets. The baskets are emptied by volunteers every other week for analysis.
For 16 months, a litter trap was placed in the Rhine River, close to the city of Cologne in Germany. Every other week, volunteers emptied the trap to see what had been caught.
‘There were lots of small pieces of plastic,’ says Nina Gnann, a researcher at Eberhard Karls University in Tübingen.
“We also found a lot of fireworks, about ten per cent, and even though we have a good deposit system in Germany, five per cent were glass bottles. There were also many plastic bottle caps.
The Rhine is one of Europe’s major rivers and is often referred to as the continent’s lifeline. It begins as two smaller streams in the Swiss Alps and winds its way 1,200 kilometres through mainly Germany before reaching the North Sea via the Netherlands.
More than half of the goods transported by inland waterways in the EU are carried on the Rhine, amounting to 285 million tonnes in 2024. The transport opportunities have meant that a fifth of the world’s chemical industry is concentrated along the river.
Ecologically, the Rhine is home to more than 70 species of fish, and its banks and delta are home to a variety of birds and mammals.
Most of the rubbish in the Rhine consists of polystyrene, such as Styrofoam and fireworks debris.
Worse than expected
The amount of debris from fireworks stands out. Although they were mainly caught in the trap during January, they accounted for as much as one in ten items during the year.
‘It’s unbelievable, because they’re only used once a year,’ says Gnann.
Previous studies have indicated that between 500 kilograms and 31 tonnes of rubbish flows through the Rhine into the North Sea each year. However, the new study suggests that the figure is closer to between 3,000 and 4,700 tonnes – up to 42 million items. At the upper end of the range, this corresponds to 470 fully loaded refuse trucks of rubbish in the river. 56 per cent is estimated to come from private consumers.
The trash trap collected large amounts of rubbish, even though it only caught waste from part of the river. Press photo.
Harmful to the environment
The enormous difference compared to previous estimates can be partly explained by the fact that earlier studies focused mainly on plastic, while the current study weighed wet objects. However, the difference is mainly due to the fact that the trap method captures more litter throughout the year.
The researchers also noticed that the amount of litter increased during naturally high water flows, when plastic and other items lying on riverbanks and beaches are carried away by the river.
Maria Granberg is a researcher at IVL Swedish Environmental Research Institute and was not involved in the study. She reacts to the large amount of litter washed out into the North Sea.
“It’s grotesque. You would think that these are countries that should have functioning collection and recycling systems for plastics, for example, so that they don’t end up in the water.
Reaching the west coast
Some of the rubbish that breaks down into smaller pieces settles on the seabed. Other waste eventually ends up along the Swedish west coast via currents. Granberg points out that the chemicals in plastic waste are particularly problematic. They can be endocrine disruptors or even toxic. If small animals and fish ingest them or are exposed to them, they can accumulate and also affect higher up in the food chain.
‘A film of bacteria and algae can form on the floating plastic particles, which smells good to birds. It has been observed that the particles can get stuck in their stomachs or give them a false feeling of satiety,’ says Granberg.
She believes that the research also sheds light on conditions in Sweden, where large quantities of plastic pellets have been found near factories around Stenungsund, for example.
‘We also have problems with many of our sewage treatment plants, which, for example, overflow (temporary discharge of untreated water) when a lot of substances are released. So we are not innocent either,’ says Maria Granberg.
The study is published in the scientific journal Communications sustainability.
With the help of a volunteer organisation and a trap, the researchers collected rubbish floating in a section of the Rhine between September 2022 and January 2024. The study’s main calculations are based on the period from 19 November 2022 to 18 November 2023.
During the statistical year, 17,523 objects larger than one centimetre were collected. Around 70 per cent of the objects were plastic, but in terms of weight, this accounted for just under 15 per cent.
