It’s not just the big rivers that are responsible for the plastics ending up in the world’s oceans.
An international team of Dutch and German researchers has mapped out the thousand rivers from which the most plastics end up in the sea.
Following the path of plastics, the team found three main driving forces behind plastic pollution: the impact of wind and precipitation; land use and terrain geography; and distance from the sea. Travel distance was found to be a major factor: the smaller the distance the plastic has to travel, the greater its chances of reaching the ocean.
Then, the researchers examined the world’s rivers using the identified factors. They pointed out that previous research had linked pollution to larger rivers, but the situation is more complicated than that.
Examining thousands of river systems, they have come to the conclusion that, due to their geographical location and the proximity of urban areas, even smaller rivers cause significant amounts of pollution to enter the seas, phys.org reports. To illustrate their findings, they have created a map showing the top 1000 rivers that contribute up to 80% of all plastics dumped into the oceans.
The thousand rivers marked with a red circle are responsible for eighty percent of plastic pollution in the world’s oceans. An interactive version of the map is available here.