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Airdate: Jul 12, 2010
Scientist: Richard Gross

Compostable Plastic

Compostable Plastic
Conventional plastic can persist for hundreds of years, but bag your produce in bio-based plastic, and you can toss the scraps AND the bag right into the compost bin.

[sfx chip bag opening]

JM: Pop open a bag of chips or a bottle of soda and you might be munching or sipping for a few minutes or even a few days. But the bag and bottle could still be around hundreds of years later. I'm Jim Metzner and this is the Pulse of the Planet. Conventional plastic is petroleum-based and can last a long, long time. But Richard Gross, professor of chemistry at Polytechnic Institute of New York University, explains how, given the right conditions, bio-based plastics have a much shorter life span. But first, of course, they have to be able to do all the things that we want plastic to do.

RG: "It has to be a plastic that people like, that has the kind of properties that they need, that they can mold into the bottles that they're used to, so they can still have their water bottles; they can still have their plastics to keep their foods fresh. But now it's a bio-based plastic, so it also has this biodegradation at the end of its life."

JM: You can buy chips and other items that are packaged in bio-degradable plastic. Dispose of them in a compost heap, and they should disappear in just a few months. But Richard Gross warns us that even biodegradable plastic is no match for a landfill.

RG: "because they keep landfills dry. Even a frankfurter that's in a landfill for 50 years, you can cut it open and it still looks pink in the middle. But if you put it in a real bio-active environment, like soil or compost, the plastic will decompose to basically new cells, carbon dioxide and water."

JM: We'll hear more about bio-degradable plastic and the microbes that feed on them in future programs. Richard Gross is one of the scientists featured in the next round of the Kids' Science Challenge, our nationwide competition for 3rd to 6th graders. Check out

Pulse of the Planet is made possible by the National Science Foundation.