One simple way to check on the environmental friendliness of something is to keep in mind the four Rs:
The problem is, once the last resort is taken, a lot of things sit in the landfill and just stay the way they were pretty much when they were first tossed. Plastic bags especially seem good at preventing things from doing what we'd like them to do: rot. People who study these things have all sorts of stories about opening garbage bags dumped in landfills in the 1970s, and the grass clippings inside are still green. That's because the plastic has prevented the grass clippings and other organic materials from getting at the natural forces that let it rot. Things like sunlight, damp, and bugs can't do their work with the plastic in the way.
So some bright spark came up with a plastic bag that biodegrades. That means it will rot, eventually, on its own. Sounds great, right? The grass clippings or whatever will be free to rot, and the plastic bag will break down into its component parts. With any luck, those component parts won't even be toxic.
Look at that four Rs list again.
The problem with biodegradable plastic bags is that they're too stupid to know if they're in a landfill or not before they start biodegrading. "Reuse" is a whole two steps above "Rubbish" — that's a long way on a four-item list. Hell, I've got Eaton's shopping bags from when they still had the skinny-lettered logo, before they switched to the boldfaced one just a few years before they went under. Those bags are over fifteen years old.
A biodegradable bag starts to biodegrade in a matter of months. Here's how I found out:
I picked up all the big pieces that I could and threw them in the — yeah — garbage, but a lot of the smaller bits were too little to pick up easily. Every time I touched one, it would break into smaller crumbs.
Vacuuming helps a bit, but the machines have a hard time picking up the bits.
See all the crumbs stuck to the underside of the vacuum? Just because it's biodegradable doesn't mean it's not still plastic. Think of the susceptibility to static charges and the overall clinginess of a typical plastic bag. Now imagine several hundred plastic bags that are all about the size of a thimble, and which break apart if you or a vacuum cleaner touches them. Right.
I've managed to track white plastic crumbs throughout my entire apartment, and so far I'm only grateful that I don't have any pets at the moment. The only cleaning solution I can think of is to buy a lint roller that uses those sticky paper things (yeah, I know, more landfill) and roll it across any parts of my floor that have plastic crumbs.
If anyone's already dealt with this and has any suggestions, I'd love to hear them.