Myth: Biodegradable Bags are the Solution
Biodegradable shopping bags may seem like a good idea, but further scrutiny reveals significant drawbacks to their use.
Biodegradable shopping bags are made of polymers that degrade, or decompose, when exposed to air, water or sunlight. There are two main types:
- The original biodegradable bags, introduced about ten years ago, are made from resins containing polyethylene, starches and heavy metals such as cadmium, lead, and beryllium. They are still on the market today.
- About five years ago, a second type was invented using starches combined with biodegradable polymers or polylactic acid. Some of these claim to be fully compostable, meaning that they would break down to organic material suitable for plant growth.
The downsides of biodegradable bags:
- Does nothing to address the consumption part of this problem which lies at the heart of this issue. Both biodegradable and regular disposable plastic bags require a similar amount of energy, natural resources and costs to produce.
- Mixing of biodegradable bags in recycling systems for conventional plastic bags creates a sorting nightmare and can render entire batches of recyclable plastic useless.
- Bag littering could easily increase as people start to believe that biodegradable bags are less harmful to the environment and will disappear quickly - it takes at least 18 months for most to breakdown.
- The breakdown of starch-based films in water consumes oxygen, resulting in oxygen depletion that contributes to algae blooms and the death of marine life.
- Water, soil, and crop contamination could result from the use of compost with chemical residues from biodegraded bags.
We're hoping too that someone will develop a magical plastic shopping bag that doesn't consume vast quantities of natural resources to make, and disappears immediately without a trace. In the meantime, do the right thing and BYOB - bring your own bag!
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