Each year, Americans throw away 25 billion Styrofoam cups. Left in a landfill, those cups will still be there, thinking about their glory days at Blockbuster's 1999 office Christmas party, for over 500 years. And as they sit there, their gross plasticky parts seep into the Earth, contaminating our water and poisoning animals. But these engineers have discovered that common earthworms will actually eat up plastic foam like so many Dots at a movie theatre.
Mealworms are actually the larvae of darkling beetles, and presumably got their names from their voracious appetites. They are a staple of classroom learning activities, where third graders put them in a box of corn flakes, and forever swear off cereal.
But what we didn't know until now is that mealworms have a taste for polystyrene, the material that makes up plastic foam, and that they can actually subsist on a diet of the stuff alone, and biodegrade it as they go. Until now, Styrofoam has been thought to be nonbiodegradable.
Mealworms have microorganisms in their gut that help them digest their food, just like humans do. And those microorganisms happen to make it possible for the worms to bacterially break down polystyrene and release carbon dioxide (which is what they release any time they eat).
In the study, co-authored by Wei-Min Wu, a senior research engineer in the Department of Civil and Environmental Engineering at Stanford, the Styrofoam-eating worms actually were as healthy as the worms eating a more typical wormy diet (corn flakes?), and on rudimentary examination, their waste appeared to be safe for use as soil for crops.
The findings could mean that a new army of earthworms will be entering our landfills soon or, more likely, that the scientists will figure out what enzymes the worms are using, and use that information to aid in breaking down old plastics, and in building new, more environmentally friendly goods.
Basically, earthworms are the larval equivalent of forgotten superhero, Matter Eater Lad.
"There's a possibility of really important research coming out of bizarre places," said Craig Criddle, a professor of civil and environmental engineering who supervises plastics research at Stanford. "Sometimes, science surprises us. This is a shock."
The research was published in the journal Environmental Science & Technology.
Photo: Julie Steiner | Flickr
