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.’
Join the Daily Mail’s battle for a world with less plastic waste
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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.’
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.’
Alarming levels of plastic waste in oceans
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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.’
HOW MUCH RECYCLING ENDS UP IN LANDFILL?
Every day, millions of us drop a plastic bottle or cardboard container into the recycling bin – and we feel we’re doing our bit for the environment.
But what we may not realise is that most plastic never gets recycled at all, often ending up in landfill or incineration depots instead.
Of 30 billion plastic bottles used by UK households each year, only 57 per cent are currently recycled, with half going to landfill, half go to waste.
Most plastic never gets recycled at all, often ending up in landfill or incineration depots instead. Around 700,000 plastic bottles a day end up as litter
Around 700,000 plastic bottles a day end up as litter.
This is largely due to plastic wrapping around bottles that are non-recyclable.
Every year, the UK throws away 2.5 billion ‘paper’ cups, amounting to 5,000 cups a minute.
Shockingly, less than 0.4 per cent of these are recycled.
Most cups are made from cardboard with a thin layer of plastic.
This lining keeps your coffee warm and stops the cardboard going soggy, but also makes the cup almost impossible to recycle.
