Instant expert

Great Pacific Garbage Patch

Sorting the truth from the trash.

Plastic bag

Credit: sxc.hu

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What is it?

The "Great Pacific Garbage Patch" is an area of accumulated marine debris in the North Pacific Ocean. More accurately, it's at least two areas - an "Eastern Garbage Patch" in a stretch of ocean between Hawaii and California and a "Western Garbage Patch" off the southern coast of Japan.

How big is it?

The patch has been described as an 'island' or an 'eighth continent' covering an area "twice the size of the continental United States". Like the plastic scattered across the Pacific, these sensationalised reports are mostly junk.

The US National Oceanic and Atmospheric Administration (NOAA) states that "there has never been a comprehensive study to measure debris in the North Pacific, thus there is currently no accurate estimate on the size or mass of either of the two garbage patches".

What does it look like?

Forget about a floating version of your local tip. The Great Pacific Garbage Patch is hard to measure because it consists of tiny plastic fragments, which are not visible to satellites. Plastics do not biodegrade, but break into smaller and smaller pieces, eventually becoming individual polymer molecules. They remain in the environment for a long time and never fully 'go away'.

Why is it a problem?

Marine creatures can mistake the small plastic pieces for food. This can damage their digestive systems or leave them feeling full, leading to starvation. Seabirds such as the Laysan albatross are particularly at risk.

There are concerns that chemicals in the plastic could get passed on to us when we eat seafood. Not only does the plastic release its own chemicals (such as the controversial bisphenol A), it can also absorb those dissolved in the surrounding seawater. Persistent Organic Pollutants (POPs) are especially worrying. This class of toxic chemicals includes pesticides such as DDT and by-products of industrial/combustion processes such as dioxins and polychlorinated biphenyls. As the name suggests, POPs persist in the environment for a long time, even after they may have been banned from use. They're readily stored in fatty tissue and can concentrate as they pass up the food chain. For example, a swordfish that has eaten a shrimp would have a higher concentration of toxins than the shrimp.

What's being done about it?

A lot of awareness-raising. So far, a raft and a catamaran made from recycled bottles have travelled through the patch. For the next stunt, Sydney filmmaker Richard Pain will cross the Pacific inside a giant (recycled!) plastic bottle. As yet there are no viable methods for removing the fragments of plastic from the oceans. Our best option is to prevent more plastic debris ending up in the oceans by keeping in mind the three Rs: Reduce, Reuse, Recycle.