Why Is 99% Of The Ocean's Plastic Missing?

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treated_bottle_slide_annaPhoto: Environmental Images/REX USA.
Millions of tons of plastic that should be floating around in the world's oceans are unaccounted for — and some of this plastic may end up on your plate.

A team of 400 researchers recently spent nine months trawling through 313 sites in the Indian, Atlantic, and Pacific Oceans, fishing for plastic. They gathered data and used it to extrapolate the total amount of plastic trash occupying our oceans across the globe: 40,000 tons overall, as the researchers revealed last week. The problem? That's only 1% of what they expected to find.

No, this isn't because plastic has started decomposing/disappearing/helping the earth in any way. Humans manufacture some 300 million tons of plastic every year, millions of tons of which (we thought) were floating around in the sea — like the notorious, Texas-sized “garbage island” that is now permanently trapped in a large eddy in the middle of the Pacific. So, where have all the bottles gone?

Researchers (reporting in the Proceedings of the National Academy of Sciences) believe the answer lies in microplastics: pieces of plastic that measure less than five millimeters across. As debris drifts on the ocean, solar radiation and waves break it down into these millimeter-sized fragments, which researchers believe are being eaten by marine animals. (Microplastics also end up in waterways via soaps, scrubs, and toothpastes — you may know them as "scrubbing" beads, and they're too tiny for filters to catch.)

This isn’t just bad news for the fish; toxic marine pollutants, including mercury, PCB (a synthetic chemical compound used as coolant fluid), and DDT (a synthetic insecticide) bind to the surface of microplastics, which are already likely to contain additives like flame retardants and plasticizers. Many of these chemicals are endocrine disrupters that, when ingested, can affect hormone levels, potentially leading to behavioral and learning disabilities, impaired sexual development, and even increased risk of cancer. When marine animals eat the microplastics, they’re ingesting these toxins along with them — toxins that may then move up the food chain and into your fish tacos.

There are other possible explanations for all this missing plastic: It could be splitting into fragments too small to be detected, or it could be washing up onshore, or the pieces could be sinking to the ocean floor, weighed down by organisms or animal feces. Regardless, The Case Of The Disappearing Plastic is an unsettling and as-yet-unsolved mystery that may be wreaking more havoc on our environment — and our bodies — than we know.