Posted on September 18, 2026
Up to a quarter of all plastic flowing from rivers into the ocean are microplastics — delivering more than 260,000 metric tons in 2022, according to a new study published last week in Science. The staggering amount suggested there was more plastic pollution carried by rivers than previously estimated, researchers said.
Almost all — 96 percent — of the pollution was from rivers in developing countries, with more than half it coming from Southeast and East Asia, according to the study. The Yangtze River in China, for example, is the largest contributor, releasing an estimated 43,000 tons of microplastic per year, despite contributing only 2 percent of global freshwater discharge.
Countries are susceptible to more of that pollution when they have a combination of high total plastic use, high rates of mismanaged plastic waste, strong rainfall and high solar radiation, the study found. The plastic flow acts like a relay race: High usage and flawed waste systems mean there is a higher volume of microplastics, while rain and solar radiation help move and break down that plastic.
As scientists continue to understand just how much microplastics infiltrate everything — from our clothing to our bodies to our oceans — Hehao Qin, co-first author of the study, said he noticed that many studies tended to either underestimate or overestimate just how much microplastic pollution in oceans comes from rivers. In setting out to answer this question, Qin, a graduate student at Peking University in Beijing, and corresponding authors Maodian Liu and Xuejun Wang, found they are a major contributor globally to ocean pollution.
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“We still need more studies like this to further narrow down this uncertainty,” Qin said.
