Tuesday, January 06, 2009

Plastic or plastic?

There's a lot of plastic out there. So much, in fact, that the ocean is filled with it. In the North Pacific alone there's so much plastic floating around that it continuously accumulates into a continent-sized area. It just collects in what the science folks call a gyre, which is sort of an intersection of ocean currents. Check out this astounding firsthand info from the Algalita Marine Research Foundation:
The North Pacific Gyre is roughly twice the size of the United States, occupying much of the North Pacific Ocean. We begin to see evidence that we are in the Eastern Patch 500 miles off the California coast. Others have found what is believed to be a Western Garbage Patch a few hundred miles off the coast of Japan. It's dimensions and location shift seasonally, and the density of debris varies. Our first investigation of plastic density in the North Pacific Gyre in 1999 found an average of .002g/m2, with the dry weight of plankton outweighed by plastic 6 times. In 2008 we replicated the same study and found an average of .004g/m2 plastic density, doubling in 9 years. The ratio of plastic to plankton was 46 to 1, likely a representation the spatial and temporal variability in plankton production, but alarming when considering the many filter feeding pelagic species that are impacted.

My readings tell me plastic doesn't biodegrade; it photodegrades, until it eventually "breaks down" into tiny plastic molecules, but it is unknown whether plastics can fully degrade and become bioavailable.

So plastic finds its way into the oceans from boat waste (e.g. nets), from coastal storms that sweep it into the water, and from rivers that transport the plastic hundreds and thousands of miles. Then it collects. And collects. And collects. And then some fish and birds and turtles eat it or get caught in it. And some of them die because of it. Or we end up eating some of these plastic-filled creatures. The plastic doesn't disappear, and we don't have any real idea of what the long-term effects of it are. Plastics floating around in water absorb chemicals that aren't water soluble, and when they get eaten those chemicals are attracted to fatty tissues where they bioaccumulate. Sucks for those of us at the top of the food chain. Plastic contains toxic chemicals from the start of its lifetime, and as it floats in the ocean it gets even more toxic. Yikes.

I read about the plastic-filled gyre more than a year ago in an issue of Harper's, and it startled me then. But now I'm shocked. And sad. It's another indication of us having absolutely no sense of moderation as a society. I try to avoid plastic whenever I can (which is really difficult in America), but I think we have to start really taking a stand on this one (remember the old styrofoam fight?); because, really, a good portion of this plastic garbage doesn't have to be made in the first place.

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