London, Oct 18 (IANS) Up to 95 per cent of the plastic polluting the world's oceans comes from just 10 rivers, including the Ganges, new research has found.
While eight of these 10 river systems are in Asia, two are in Africa.
The findings published in the journal Environmental Science & Technology showed that large rivers play a particularly large role - not only because they also carry a comparatively large volume of waste on account of their larger discharge.
"The concentrations of plastic, i.e. the quantity of plastic per cubic metre of water are significantly higher in large rivers than small ones. The plastic loads consequently increase at a disproportionately higher rate than the size of the river," said Christian Schmidt, a hydrogeologist at the Helmholtz Centre for Environmental Research - UFZ in Leipzig, Germany.
"Halving the plastic input from the catchment areas of these rivers would already be a major success," Schmidt added.
"To achieve this, it will be necessary to improve the waste management and raise public awareness for the issue. We hope that our study will make a contribution to a positive development so that the plastic problem in our oceans can be curbed in the long run," Schmidt said.
For the study, the researchers analysed various scientific studies that examined the plastic load - that is the quantity of plastic carried by the water - in rivers.
They converted the results of the studies into mutually comparable datasets and determined the ratio of these figures to the quantity of waste that is not disposed off properly in the respective catchment area.
"We were able to demonstrate that there is a definite correlation in this respect," Schmidt said.
"The more waste there is in a catchment area that is not disposed off properly, the more plastic ultimately ends up in the river and takes this route to the sea," Schmidt added.
The researchers found that 10 rivers transport 88-95 per cent of the global plastic load into the sea.