Are those blue “biodegradable doggie bags” at the pet store REALLY biodegradable?

I recently responded to a post on this website: http://www.jacko.com/theweblog/2007/01/02/california-biodegredation about those blue doggie bags sold in pet stores.  The blogger wrote: While browsing the pet store the other day I picked up some refill doggie bags (and I’m not talking the kind of doggie bag you get in a restaurant) for our little Bags on Board dispenser. I was pleased to see that these bags were now “100% Biodegradable”. It wasn’t until I got home with them that I realized this was “except as defined by California”. And this is a pity, because Jackson poops almost exclusively in California.

Looking now, their website doesn’t actually mention the biodegradable thing (although you can see the little red stickers, and in fact these stickers don’t have that little disclaimer).

It turns out that this is not the fault of slacking Californian anaerobes, but legislation passed recently by the California Assembly which apparently is the first piece of legislation anywhere to put legal limits on the use of the term “biodegradable”. According to California, something is biodegradable if the ASTM Standard Specification for Compostable Plastics says it is. Unfortunately it costs $30 find out what that says.

MY ANSWER:

The technical definition of "biodegrade" means that something can be "decomposed by biological agents, usually bacteria."  The bags Chris bought are photodegradable (meaning sunlight will break them down) but nothing biological will break down the bags.  The catch with plastic is that although it is photodegradable it will NEVER decompose (meaning it won’t be broken down into elements, as in the periodic table of elements) and return to the earth.  Plastic just photodegrades into smaller and smaller and smaller pieces until it is practically invisible to the naked eye but is still present.  My big concern is when we get to the point where we have all this photodegraded plastic in our soil and can’t grow anything anymore and can’t figure out a way to get the plastic OUT of our soil.