A map showing where plastics enter the oceans from rivers.

(The Ocean Cleanup)

At a Glance

Between 1.15 and 2.41 million metric tons of plastic are deposited into oceans each yearTwenty rivers worldwide are responsible for two-thirds of the plastics deposited in oceans.

Between 1.15 and 2.41 million metric tons of plastic are deposited into oceans each year, with 20 riversalone out of more than 45,000 responsible for two-thirds ofthat amount, a new study says.

According to the in the journal Nature, researcher Laurent Lebreton of the , an organization that develops advanced technologies to rid the world’s oceans of plastic, designed a model drawing from data onwaste management, population density,dam locations, hydrography and topography.

The researchers discovered that 20of 40,760 rivers worldwide contribute two-thirds of the plastic input. They also determined that more plastic enters the oceans via rivers between the months of May and October.

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To illustrate the issue, the organization developed an that shows how many kilograms of plastic have entered the oceans. According to the map, the rivers that seem to pollute the most are concentrated in Southeast Asia, India, central and eastern South America andwestern Africa.

“We’re pleased to see how many initiatives have been taken in the past few years to raise awareness of theocean pollution problem," the Ocean Cleanup founder and CEOBoyan Slatsaid in a statement, "However, for our work in the deep ocean to succeed in the long run, it’s crucial that governments and other organizations speed up their efforts to mitigate the sources of the problem we aim to resolve. The results of this latest study can assist with those efforts.”

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The results of the study come days after United Secretary General Antonio Guterrescited that found that plastics could outweigh fish by 2050 at the first-ever Ocean Conference.

In his speech, Guterres issued , saying they are "under threat as never before."

"Pollution, overfishing and the effects of climate change are severely damaging the health of our oceans," he said. "According to one recent study, plastic could outweigh fish — if nothing happens — in our seas by 2050."

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Hong Kong

Doug Woodring, an entrepreneur and conservationist who lives in Hong Kong, displays rubbish on May 07, 2009 on a beach on the south side of Hong Kong which has been left uncleaned. (MIKE CLARKE/AFP/Getty Images)