As much as 95 percent of the plastic waste transported by rivers into oceans comes from just ten rivers, a study has shown.

Eight of those rivers are in Asia, with the remaining two — the Nile and the Niger — in Africa.

The report, conducted by the Helmholtz Centre for Environmental Research in Germany, estimates that between 0.41 and 4 million metric tons of plastic waste in oceans derives from rivers, based on an analysis of previous studies of 1,350 large rivers around the world. It then concluded that the 10 most polluted rivers account for 88 to 95 percent of that amount.

The difference of 7 percentage points — between 88 and 95 percent — is due to the two different models used in the study. One measures only microplastic while the second includes studies on both micro- and macroplastics.

The worst offenders are some of the longest and largest waterways in the world and are in countries with poor waste management when it comes to collection, dumping and recycling.

They’re also the rivers with the largest population of people living alongside them, with rivers from inland areas particularly affected.

While it would be impossible to clean up the damage already done, the report estimates that tackling the sources of pollution along these rivers could see overall plastic pollution from rivers almost halved.

Dr. Christian Schmidt, a hydrogeologist and lead author of the report, said: “’Reducing plastic loads by 50 percent in the 10 top-ranked rivers would reduce the total river-based load to the sea by 45 percent.”

“Our analysis reveals that plastic loads of large rivers disproportionately increase in relationship to the increase of plastic debris available for transport.”

The biggest offenders are indeed two of the largest rivers in the world, with the Yangtze and the Ganges estimated to carry over 900,000 tons of plastic between them to the ocean every year.

Researchers now plan to study how long plastic takes to get to the sea once in the river, which Schmidt says is key to working out how best to prevent it.

The amount of plastic in our oceans is killing wildlife and damaging habitats. With up to 13 million tonnes of it finding its way to the sea every year. Scientists predict that the amount of plastic in the sea could outweigh fish by 2050.

Last week, the United Nations passed a resolution that called for greater action “to prevent and significantly reduce marine pollution of all kinds” by 2025.

Editor’s note: This article syndicated from The Sun, which ran with the original headline “10 rivers are responsible for 90% of the plastic in the ocean,” falsely claimed that up to 95 percent of the total plastic debris in the world’s oceans comes from only 10 rivers. The error has been corrected in this version by the New York Post.