In a study published in Environmental Science and Technology, scientists analysed data along 57 rivers, and were able to calculate the main culprits of plastic in rivers flowing to the sea.
"The rivers with the highest estimated plastic loads are characterized by high population - for instance the Yangtze with over half a billion people," author Dr Christian Schmidt told the DailyMail.
"These rivers are also in countries with a high rate of mismanaged plastic waste (MMPW) production per capita as a result of a not fully implemented municipal waste management including waste collection, dumping and recycling."
The scientists say this causes enormous environmental damage.
"Pollution of the marine environment with plastic debris is widely recognized and is of increasing ecological concern because of the chemical persistence of plastics and their mechanical fragmentation to so-called micro-plastics which can be ingested by even small organisms such as zooplankton," Dr Schmidt said.
"Beyond the long recognized occurrence of plastic debris in the marine environment plastic debris has been more recently detected in freshwater environments and can be found even in pristine, remote locations."
The ten worst rivers and the seas they flow to:
- Yangtze, East China Sea, Asia
- Indus, Arabian Sea, Asia
- Yellow River, Yellow Sea, Asia
- Hai He, Yellow Sea, Asia
- Nile, Mediterranean, Africa
- Meghna, Bay of Bengal, Asia
- Ganges, Bay of Bengal, Asia
- Amur, Sea of Okhotsk, Asia
- Niger, Gulf of Guinea, Africa
- Mekong, South China Sea, Asia