“Corn” Plastic: The Good, The Bad and The Ugly
“Would you like a bag with that?”, asks the girl at the grocery store check-out. You glance at the couple of items purchased, and think of the walk home. She sees you hesitating and adds “It’s okay; these plastic bags are biodegradable. In fact, they’re made of corn!”
“Perfect!”, you think. Or is it?
The Good
This specific type of plastic is called PLA, or Polylactic acid. Simply put, PLA is created by fermenting the starch of corn kernels. Plastic made from PLA look and feel exactly like regular plastic, and PLA plastic bags are just as durable and lightweight as their non-PLA counterparts.
A renewable resource, PLA or “corn plastic” is 100% compostable. Under the right conditions, PLA breaks down in about one to six months in a commercial composter.
The Bad
But wait… what about in a landfill? As we all know, unless recycled, plastic bags that are used for groceries end up in city landfills, not commercial composters. In order to biodegrade, the PLA must receive sufficient amounts of oxygen, water, light and soil, which are not usually present in a landfill. Thus, it can take corn plastic just as long as regular plastic to break down—up to one thousand years. Unfortunately, that means that using corn plastic bags to line trash cans is no better than using regular plastic.
