Is it true that 90% of the plastic in the oceans comes from 10 rivers in Asia and Africa?
This claim is probably false. It misquotes the results of research published in 2017. In that study, scientists estimated how much plastic enters the sea from rivers around the world. Ten of these river systems carried most of the plastic. But plastic also reaches the sea through other ways, not just rivers. So the total amount of plastic entering the ocean is higher than just this riverine input. New research suggests that a much larger number of rivers are involved in carrying plastics to the sea.
Detailed information
There are many ways that plastics can reach the ocean. It can be dumped or lost directly on coasts and beaches, or from ships or platforms off-shore. It can travel through the air via the wind, over surfaces or through urban drainage systems. It can also float down rivers. So rivers are just one pathway for plastics to reach the sea.
In 2017, a study from the Helmholtz Centre for Environmental Research – UFZ in Germany examined the export of plastic debris by river systems to the ocean. The researchers calculated that 88 to 95 percent of all plastics transported by rivers to the sea came from just 10 river systems, eight of which were located in Asia and two in Africa.
A study from 2021 updated this estimate, concluding that emissions are more widely distributed. The researchers calculated that 1000 rivers account for 80 percent of riverine plastic input into the ocean.
However, there is still “a large discrepancy between the amount of plastic being modelled to leave the river systems, and the amount of plastic that has been found in the seas and oceans”, scientists pointed out in 2022. This is due to a lack of data and the uncertainty of the models, as well as the number of rivers considered.
In conclusion, there is still a high degree of uncertainty regarding the quantity of plastic that enters the ocean via rivers — and other pathways. It is also uncertain which regions or rivers contribute the biggest share of plastic pollution to the ocean.
Expert check
Thanks toTim van Emmerik, Hydrology and Environmental Hydraulics Group, Wageningen University andKristian Syberg of Roskilde University for scientific fact-checking.
Updated on: October 4, 2023