In 2007, 1.4 billion pounds of PET (polyethylene) plastic were recycled curbside. PET is the basis for a lot of product packaging including water/soda bottles, clam shell packaging, etc. With the recent, yet unregulated, shift of products to be "more green", some plastics manufacturers have started putting additives into plastics to help them break down quicker (presuming the will end up in a landfill and not a recycle bin).
While many of these manufacturers have had independent testing done to back up their claim of plastics that "break down faster" in a landfill, there are still a lot of questions being asked. In order for plastic to break down, you need exposure to heat, water and organisms. Burying anything 30 feet underground lacks any of the three. In fact, as I discussed in a prior post, there have been studies of newspapers being removed from landfills thirty years later and being completely readable!
NAPCOR (National Association for PET Container Resources) recently issued a restraint on companies manufacturing PET containers with these additives until more public data is available. The concern is the service life of these "degradable plastics" and the impact will have on therecycling stream with regards to the manufacturing of new products from recycled waste.