Thousands of Tonnes of River Litter Flow into the North Sea Each Year
New research has revealed that thousands of tonnes of litter are entering the North Sea annually via the River Rhine, polluting marine environments with microplastics, heavy metals and harmful chemicals. This growing river pollution crisis highlights the urgent need for action to protect both ecosystems and human health.
The study was published in the journal Communications Sustainability.
How River Pollution Threatens Wildlife and Human Health
The litter carried by rivers is not just unsightly – it is dangerous. Items such as vehicle tyres contain zinc and other heavy metals which, when present in high concentrations, can be toxic to aquatic life. Over time, these pollutants accumulate in food chains, posing long-term risks to wildlife and people alike.
“Even natural, less persistent materials, such as worked wood, paper, cardboard and food waste may contain toxic or harmful additives,” said Dr Leandra Hamann, a zoologist at the University of Bonn and lead author of the study.
Rivers Are Major Pathways for Marine Litter
Rivers play a critical role in transporting waste from land to sea. Researchers found that the composition of litter in the Rhine closely mirrors that of other major European rivers, including the Thames. This suggests that river-driven marine litter is a widespread problem across Europe, not an isolated case.
In addition to harming biodiversity, large volumes of river litter can damage drainage systems and other vital infrastructure, increasing the risk of flooding in nearby communities.
Research Reveals Scale of Macrolitter in the Rhine
Between November 2022 and November 2023, citizen scientists and researchers from the University of Bonn analysed litter collected from the Rhine. Their findings were stark: the river carries up to 4,700 tonnes of macrolitter every year, defined as litter pieces larger than 25mm.
Researchers stress that more studies are needed to fully understand the scale of river pollution, especially as many European rivers have not yet been investigated.
The Rhine: A Major Contributor to North Sea Pollution
According to lead researcher Hamann, the Rhine is one of Europe’s largest contributors of macrolitter entering the sea. However, he warned that the true extent of the problem is likely much greater, as countless rivers remain unmonitored.
Floating Litter Traps Expose Everyday Waste
To track pollution levels, a floating litter trap was installed in Cologne. Of the nearly 2,000kg of rubbish collected, researchers found:
- 15% was plastic
- 28% was food and drink-related waste
These figures highlight how everyday consumer behaviour directly contributes to river and ocean pollution.
The Power of Citizen Science in Tackling River Litter
Hamann praised the “really great work” of citizen scientists involved in the project. Volunteers played a vital role by:
- Collecting litter from the trap
- Transporting it to monitoring sites
- Logging each item using a custom-built app
This project demonstrates how community action and scientific research can work together to tackle environmental challenges.
At Natural World Fund, we support initiatives that protect marine biodiversity and advance sustainable ocean management. Protecting the high seas is vital to maintaining healthy oceans and securing a thriving planet for future generations.