Biodegradable poly bags and other green alternatives to plastic grocery and shopping bags are becoming more and more popular. They offer some nice features if you're trying to grow a greener world, but they aren't all things to all people.
The Truth About Biodegradable Poly Bags
Biodegradable plastic (poly) bags are designed to break down in the environment. They pose less of a hazard to neighborhood ecosystems and sometimes contribute less, long-lasting, plastic material to landfills. Recently, the Boston Globe reported that the number of plastic bags used by American consumers is over 380 billion a year.
To reduce those numbers, technologies have been developed to speed up the decaying process of poly bags. Unlike some substances, polythene (or polyethylene) bags will decay in the environment, naturally; however, it takes decades for this to happen without a little help from new advances in the green science. The science can be tricky, though. Bags have to survive long storage, be strong enough to hold groceries and other items and yet, still be broken down quickly once exposed to wind, water, light, or another trigger to start the decomposition process. Different technologies hasten decay at different rates. There are other things that create confusion, too. It isn't always easy to determine what type of technology makes a plastic bag biodegradable. The technology involved determines how effectively and how quickly a bag will degrade.
- Cornstarch Impregnated Bags: Almost half of the biodegradable poly bags use cornstarch incorporated into the plastic. The cornstarch component will begin to decay when exposed to a microbe rich environment (like a landfill). This breaks the plastic into tiny pieces. When it works well, the bag is totally deconstructed. This doesn't always happen as advertised. When it doesn't work, a bag may just become perforated but maintain its basic shape.
- Photo Sensitive Bags: These bags are designed to decay with prolonged exposure to the ultra violet rays in sunlight. If they're buried in a landfill or find their way into sewers, the process won't work properly and most of the plastic will remain intact.
- Oxo-Biodegradable Bags: These bags are among the most economical to manufacture and the most effective to use. They are completely biodegradable. This happens in a two-step process. First, the bag is oxidized by prolonged exposure to the oxygen in the air. After that, the oxidized fragments convert into carbon dioxide, a harmless biomass and water. It's an elegant process.
- Bags Using Aliphatic Technology: Somewhat similar to using starch to encourage nature to deconstruct poly bags, Ailphatic poly bags also rely on microbes to breakdown the bag into its constituent molecules. Although these bags are effective, they're also expensive to produce.
Biodegradable plastics are being used or considered for lots of industries, and the more you support biodegradable technology, the more likely it is that responsible environmental practices will become more widespread within the manufacturing industry. Look for biodegradable plastics when purchasing products in these industries:
- Bakery packaging
- Dry cleaning bags
- Food packaging
- Hardware items
- Medical devices and consumable items
- Promotional mailers
When you consider using biodegradable plastic bags, think of using them for more applications than just toting groceries home from the store.