A shocking study has revealed 90 per cent of the world's plastic waste comes from just 10 rivers in Asia and Africa.

As governments around the world rush to address the global problem of plastic pollution in the oceans, researchers have now pinpointed the river systems that carry the majority of it out to sea.

About five trillion pounds is floating in the sea, and targeting the major sources - such as the Yangtze and the Ganges - could almost halve it, scientists claim.

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China's Yangtze River was the worst polluter, and ferries some 1.5 million tonnes of plastic into the Yellow Sea every year, the study found. Pictured, workers clear rubbish in Taicang reach of Yangtze River on December 23, 2016 in Taicang, Jiangsu Province of China.

THE 10 MOST POLLUTING RIVERS Yangtze East China Sea Asia Indus Arabian Sea Asia Yellow River Yellow Sea Asia Hai He Yellow Sea Asia Nile Mediterranean Africa Ganges Bay of Bengal Asia Pearl River South China Sea Asia Amur Sea of Okhotsk Asia Niger Gulf of Guinea Africa Mekong South China Sea Asia Advertisement

Carried out by Germany's Helmholtz Centre for Environmental Research, it suggests that the most effective way of reducing the amount of plastic in the world's oceans is by addressing the sources of pollution along such waterways as these.

The researchers, who first released their paper in 2017, issued a chilling warning for the future.

'One thing is certain: this situation cannot continue,' Dr. Christian Schmidt, a hydrogeologist at the Germany's Helmholtz Centre for Environmental Researchsaid when the study was first published.

'But as it is impossible to clean up the plastic debris that is already in the oceans, we must take precautions and reduce the input of plastic quickly and efficiently.'

His team analysed data on debris from 79 sampling sites along 57 rivers - both microplastic particles measuring less than 5 mm and macroplastic above this size.

China's Yangtze River was the worst polluter, and ferries some 1.5 million tonnes of plastic into the Yellow Sea every year, the study found.

They said microplastics in particular can damage the health of marine life but cleaning it all up would be impossible.

China's Yangtze River was the worst polluter, and ferries some 1.5 million tonnes of plastic into the Yellow Sea every year, the study found

Schmidt told Dailymail.com he is working on improving it with the latest research.

'As there is more and more data published on plastics in rivers we would like to incorporate these in our estimates.

He said the team was also working to improve their model to include things like retention, where plastic is 'stranded' on riverbanks.

'When you look at river banks and sediments there is a lot of plastic stored, ' he said.

'We are trying to get a better handle on this.'

Stemming the tide of the waste could help reduce the potential harm.

Dr Schmidt said to do this, researchers need a better understanding of how plastic makes its way into the oceans in the first place.

The researchers say that slashing the dumped plastic in these areas by 50 per cent would have a dramatic effect.

'Halving the plastic input from the catchment areas of these rivers would be a major success,' said Schmidt.

'To achieve this, it will be necessary to improve waste management and raise public awareness of the issue.'

The Yangtze has been estimated in previous research to dump some 727 million pounds of plastic into the sea each year.

The Ganges River in India is responsible for even more - about 1.2 billion pounds.

A combination of the Xi, Dong and Zhujiang Rivers (233 million lbs per year) in China as well as four Indonesian rivers: the Brantas (85 million lbs annually), Solo (71 million pounds per year), Serayu (37 million lbs per year) and Progo (28 million lbs per year), are all large contributors.

The river systems that carry the most waste into the ocean include the Amur, Ganges, Hai, Indus, Mekong, Pearl, Yangtze and Yellow Delta in Asia, as well as the Niger and Nile (pictured) in Africa, a research paper has revealed

The study suggests that the most effective way of reducing the amount of plastic in the world's oceans is by addressing the sources of pollution along such waterways as these (pictured: the River Indus)

'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.'

Rivers which flow from inland areas to the seas are major transporters of plastic debris but the concentration patterns aren't well known.

The findings could help fill in this knowledge gap.

Dr Schmidt pooled data from dozens of research articles and calculated the amount in rivers was linked to the 'mismanagement of plastic waste in their watersheds.'

He said: 'The 10 top-ranked rivers transport 88-95 per cent of the global load into the sea.'

IS BANNING PLASTIC SHOPPING BAGS EFFECTIVE? Critics of Australian supermarkets' plastic bag ban continue to drum up protest, as it is revealed that 90 per cent of the world's plastic waste comes from just ten particular rivers in Asia and Africa Ruth Barcan, associate professor at the University of Sydney, says that Woolworths and Coles' move to ban plastic shopping bags sees them taking a stand on a 'low-hanging fruit' issue, insofar as it doesn't require real sacrifices. As a point of contrast, she compares the matter of plastic bags - visible, physical, material - to slightly less obvious environmental threats such as climate change. 'There's a tipping point happening around plastic … [and] it seems to me that in countries like Australia part of it is it's something that's visible unlike carbon,' she said. 'It's something that people can take some control over and have a sense that we can actually get somewhere ... people are going 'plastic we can do something about' … it's the kind of low-hanging fruit that people are desperate to see.' Advertisement

The results show large rivers play a critical role.

'The rivers with the highest estimated plastic loads are characterised by high population - for instance the Yangtze with over half a billion people.

'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 team wrote in the journal 'Environmental Science & Technology' that the problem has now become a global issue.

'Minute plastic particles can be found in the water in virtually every sea and river. This constitutes a serious and growing global environmental problem.

'There are enormous quantities of input each year and plastic weathers only very slowly.

'Marine life can be harmed by the tiny plastic particles floating in the water.

'One example of how this happens is when fish, seabirds or marine mammals mistake the particles for food and consume them.'

China's Yangtze River (pictured) - the worst polluter - ferries some 1.5 million tonnes of plastic into the Yellow Sea every year

Ruth Barcan, associate professor at the University of Sydney, says that Woolworths and Coles' move to ban plastic shopping bags sees them taking a stand on a 'low-hanging fruit' issue, insofar as it doesn't require real sacrifices

The researchers analysed various scientific studies that examined the plastic load - the quantity of plastic carried by the water - in rivers.

They then determined the ratio of these figures to the quantity of waste that is not disposed of properly in the respective catchment area.

'We were able to demonstrate that there is a definite correlation in this respect,' says Schmidt.

'The more waste there is in a catchment area that is not disposed of properly, the more plastic ultimately ends up in the river and takes this route to the sea.'