A newly published paper in the journal Environmental Science and Technology, has found that only 10 rivers in the world – eight of them in Asia – are responsible for dumping almost four million tonnes of plastic into the seas every year.
Researchers calculated that rivers contribute between 410,000 and four million tonnes a year to oceanic plastic waste, with 88 to 95% coming from just 10 rivers.
The study was carried by scientists from the Helmholtz Centre for Environmental Research and the Weihenstephan-Triesdorf University of Applied Science, in Germany.
The rivers are
- China: Yangtze, Xi and Huanpu
- India: Ganges
- Cameroon and Nigeria: Cross
- Indonesia: Brantas and Solo
- Brazil: Amazon
- The Philippines: Pasig
- Myanmar: Irrawaddy
It’s extremely difficult to make accurate estimates on how much plastic is ending up the oceans because of a conflict in the data. On one hand, we have large estimates on the amount of plastic dumped in the oceans based on what is known about plastics produced, used, recycled and dumped in landfill and on the other hand, the amount actually observed in the water doesn’t match our estimates.
The team analyzed plastic concentrations in 240 different samples from 79 locations covering 57 rivers. They also classified plastic particles into those smaller or larger than five millimeters in size, and treated each cohort separately to make their calculations. They concluded that only a few rivers in the world are responsible for the majority of plastic waste in the oceans.
“Reducing plastic loads by 50% in the 10 top-ranked rivers would reduce the total river-based load to the sea by 45%,” the team said.