Do 10 Asian and African rivers generate 90% of plastic trash in the ocean?

Question

I found this image shared on Facebook [Warning: image contains a bleeding turtle.] with the following text:

Your Straws Did NOT Do This

[image of turtle with foreign body in nostril]

Americans are being told we must risk our health with expensive, awkward reusable or paper straws. All because of this suffering turtle.

But in real life, this turtle was found near Costa Rica, not the US. And Costa Rica dumps its trash directly into rivers and the ocean.

The US never does that. It's been banned by Federal law for 45 years. Discard your straw in a normal trash receptical (sic), and turtles are safe.

In Fact:

10 Asian and African Rivers Generate 90% of Plastic Trash in the Ocean

Americans create almost none of the ocean's plastic.

The World Economic Forum makes a similar claim:

By analyzing the waste found in the rivers and surrounding landscape, researchers were able to estimate that just 10 river systems carry 90% of the plastic that ends up in the ocean.

While I can imagine that third-world countries might not have well-established waste disposal processes, 90% sounds exaggerated.

Answer 1

No, rivers and other land-based sources account for 10-12%

From Wikipedia:

Sources of ocean-based plastic pollution

Almost 90% of plastic debris that pollutes ocean water, which translates to 5.6 million tons, comes from ocean-based sources. Merchant ships expel cargo, sewage, used medical equipment, and other types of waste that contain plastic into the ocean. Naval and research vessels eject waste and military equipment that are deemed unnecessary. Pleasure crafts release fishing gear and other types of waste, either accidentally or through negligent handling. The largest ocean-based source of plastic pollution is discarded fishing gear (including traps and nets), estimated to be up to 90% of plastic debris in some areas.[3]

Source: Plastics in the Marine Environment: The Dark Side of a Modern Gift

This 2012 review explains a much smaller percentage comes from land-based sources:

Approximately 0.8 million tons annually of marine debris, which is 12% of the total debris input into the oceans, originates from land-based sources, and primarily consists of discarded plastic items (user plastic). In highly populated areas, marine debris comes primarily from the land.

So what about that study?

The study — Export of Plastic Debris by Rivers into the Sea — says in its abstract (emphasis mine):

We analyzed a global compilation of data on plastic debris in the water column across a wide range of river sizes. Plastic debris loads, both microplastic (particles <5 mm) and macroplastic (particles >5 mm) are positively related to the mismanaged plastic waste (MMPW) generated in the river catchments. This relationship is nonlinear where large rivers with population-rich catchments delivering a disproportionately higher fraction of MMPW into the sea. The 10 top-ranked rivers transport 88–95% of the global load into the sea.

In other words: they did not examine the ocean, they examined rivers. And their number does not say that 88-95% of the plastic that has ended up in the ocean comes from these 10 rivers, but that of the Mismanaged Plastic Waste that rivers in particular contribute to the oceanic plastic pollution, these 10 rivers account for 88-95% of that contribution.

But(!) as the study above says, rivers and other land-based sources of oceanic plastic waste account for 10-12% of the total plastic waste in the ocean.

Update

@MadScientist concludes that the Wikipedia quote may be erroneous, and the 90% figure may be off by a bit.

This however does not change the fact that Export of Plastic Debris by Rivers into the Sea does not deal with all plastic waste that end up on the oceans but only that which arrives by river.

This — by all means — strengthens the original claim that it is in all likelihood not "your" straw that ended up in the nose of this unlucky turtle unless you were carelessly discarding it directly into the ocean or nearby that. Never the less the facts stated are misinterpreted and rivers are not the only and probably not even the majority sources of plastic pollution in oceans as a whole other than in the immediate vicinity of where rivers discharge into the sea.

Answer 2

If the question is about those specific countries:

No, plastic in those rivers can have come from a different country.

..Therefore, the rivers might be Asian/African, the plastic is not (therefore, the responsibility of it being recycled does not fall solely on those countries).

MichaelK's answer is excellent. I would just like to add the fact that there are a few articles around stating that 'developed' countries are even exporting recycled, plastic and other such to other less developed ones (basically pay other countries to accept it). So the stats a study might have become even more obscured.

A few come around with a simple google search:

The Independent: UK now exporting more waste to countries with highest levels of ocean plastic pollution

Not about plastic so much, but e-waste article from Greenpeace: Where does e-waste end up?

More here:

The BBC: Reality Check: How much plastic do we send to China?

The New York Times: Your Recycling Gets Recycled, Right? Maybe, or Maybe Not

From the starting paragraph of wikipedia on the subject:

'Toxic or hazardous wastes are often exported from developed countries to developing countries, also known as countries of the Global South. Therefore, the burden of the toxicity of wastes from Western countries falls predominantly onto developing countries in Africa, Asia, and Latin America.Global waste trade[1]'

Further, it is suggested that the 'recycled' plastic which is exported, often ends up in a state which is no longer recycle-able.

Extract from 5gyres:

'In countries like India, waste pickers sort through the trash to find the pieces that are most valuable—thicker plastics and metals. The remainder becomes landfilled or incinerated, creating a health crisis for communities. Local waterways act like conveyor belts, sending plastic straight out to sea.' Think you're doing your part by recycling?.

P.S. This is my first attempt at a (complimentary) answer. I don't have enough reputation to move this to a (very long) comment, and if there's something i did wrong please let me know. Thanks ;)

Answer 3

America generates 50% of the world's plastic trash. When China banned recycling for foreign countries earlier this year, trash started piling up all over ports in the United States. It was deemed as a crisis in many states.

Wall Street Journal and many other outlets did a pretty extensive coverage on this issue, and there are some very good video documentaries too.

1. https://www.wsj.com/articles/u-s-recycling-companies-face-upheaval-from-china-scrap-ban-1533231057?mod=e2tw
2. https://www.ecowatch.com/plastic-waste-crisis-recycling-2597495368.html
3. https://www.reuters.com/article/us-china-hongkong-paperrecycling/china-ban-on-waste-imports-leads-to-piles-of-paper-abroad-surging-prices-in-china-idUSKCN1C30GR