This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Plastic that enters the environment does not necessarily make its way to the sea via rivers. In fact, only a tiny fraction eventually reaches river mouths.
Most plastic remains on land or within river systems. This is the finding of new research by Wageningen University & Research (WUR) and international partners, covering more than 8,600 European river basins. The Rhine ranks third among Europe's most plastic-polluted rivers, after the Kurbagalı Dere in Türkiye and the Vistula in Poland.
Rivers are often seen as major transport routes for plastic waste to the sea. However, far more plastic is retained along the way than previous models have accounted for. For example, plastic can become trapped along riverbanks, in vegetation or behind dams.
Much of it never even reaches a river, as it remains on land. To better understand where plastic ends up, the researchers developed a new model that calculates not only how much plastic reaches river mouths, but also how much remains on land and within river systems. They distinguished between microplastics (smaller than 5 millimeters) and larger pieces of plastic.
The study, "River Plastic Retention and Export across Europe," is published in Environmental Science & Technology. The findings are striking. Of the estimated 3.55 million tonnes of plastic that entered the European environment in 2015, the reference year used in the model, more than 93% remained on land and never entered rivers.
Another 6% was retained within rivers, along riverbanks or in sediments. Only 0.6%, approximately 20,000 tonnes, reached river mouths. The study provides a new ranking of European rivers based on the total amount of plastic retained within their river systems.
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