Plastic waste heading for oceans quantified

About eight million tonnes of plastic waste find their way into the world's oceans each year, say scientists.

Any walk along a beach will produce a sizeable haul of plastic waste

The new study is said to be the best effort yet to quantify just how much of this debris is being dumped, blown or simply washed out to sea.

Eight million tonnes is like covering an area 34 times the size of New York's Manhattan Island to ankle depth.

The details were released at the annual meeting of the American Association for the Advancement of Science (AAAS).

Dr Jenna Jambeck, the study’s lead author from the University of Georgia, had another way to try to visualise the scale of the problem.

The quantity entering the ocean is equal to about five plastic grocery bags full of plastic for every foot of coastline in the world,” she told BBC News.

Unseen pollution

Researchers have for some time now reported on the mass of plastic caught up in ocean currents, just going round and round.

What is slightly shocking about this new study, also published in Science Magazine, is that it helps quantify all the plastic in our oceans - not just the material seen floating on the sea surface or sitting on beaches.

The newly published estimate is 20 to 2,000 times greater than the reported mass of plastic trapped in high concentration in ocean gyres.

It is clear now that large quantities of debris must be hidden on the seafloor or have been weathered into tiny fragments that are just not apparent to casual surveys. The latter are being ingested by marine animals with unknown consequences.

Plastics will break down into tiny, persistent fragments that can then be ingested by animals

In doing its analysis, the team pulled together international data on population, waste generation and management (and mismanagement). The group then modelled scenarios for the likely sums of plastic getting into the ocean environment.

For 2010, the estimated range runs from 4.8 to 12.7 million tonnes. Eight million tonnes is the mid-scenario. It is a few percent of the total plastic waste generated that year.

In doing its analysis, the team pulled together international data on population, waste generation and management (and mismanagement). The group then modelled scenarios for the likely sums of plastic getting into the ocean environment.

For 2010, the estimated range runs from 4.8 to 12.7 million tonnes. Eight million tonnes is the mid-scenario. It is a few percent of the total plastic waste generated that year.

Jenna Jambeck's study tries to quantify the inputs. It is not a census of what is out there

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From BBC News