Biodegradable Plastic Bags
Do they really disappear or is this another example of green hype?
I’ve been reading a lot lately about biodegradable trash bags. Do they actually break down or is this just a bunch of greenwashing? Brennan P. Vancouver
“Biodegradable” is a big buzzword in green products these days. Whether it’s your trash bags, your drain cleaner or even your couch, there’s someone out there making it “biodegradable.” But when it comes to plastic trash bags, will the biodegradable versions ever disappear?
Conventional plastic, made with petroleum, is one of the only materials on earth that never goes away. Even when it’s exposed to heat and sunlight, plastic breaks apart into tiny particles that contaminate soil or, in oceans and waterways, absorb toxic chemicals that can be ingested by the fish we eventually eat.
Manufacturers of biodegradable plastics, on the other hand, aim to eliminate those problems by creating products that break down into harmless substances like water, carbon dioxide and biomass.
There are two types of biodegradable plastics currently on the market. The first are “bio-based” polymers made from corn, sugarcane or potatoes.
The second kind are made with synthetic plastics mixed with additives that allow the plastic to break down more quickly when exposed to light, heat and oxygen. Here, the term “biodegradable” can be misleading. They’re often “oxo-degradable” or “ pho-todegradable,” meaning they degrade when exposed to air or light, but not necessarily when they’re buried underground.
Both types have one fundamental flaw: They’re often destined for landfills, and nothing biodegrades 100 percent in an airtight landfill. Archaeologists have found perfectly legible 40-year-old newspapers alongside equally old, but practically fresh, heads of lettuce in landfills across the country. And despite manufacturer claims that biodegradable plastics will disappear in the airtight confines of a landfill, independent tests have yet to confirm that.
What’s more, the additives in both bio-based and synthetic bags are made with nonrenewable resources. One, cobalt stearate, is fatal to animals if ingested.
So what, then, should we be using to take out the trash? If you live in one of the few U.S. cities that compost garbage, the bio-based bags are certainly the way to go. For the rest of us who send trash to landfills, synthetic biodegradable plastics are a better alternative to regular bags but not as good for the environment as bags made from recycled plastic.
GG PRODUCT PICKS
EarthSense Kitchen Trash Bags
made with 70 percent recycled plastic,
10 percent post-consumer ($2.15/30;
greenlinepaper.com)
Seventh Generation Drawstring Tall
Kitchen Bags
45 percent recycled plastic,
25 percent post-consumer ($4.99/20;
drugstore.com)
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