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''Biodegradable'' label may be bad news for global warming

By Colin Ricketts - 01 Jun 2011 17:21:0 GMT
''Biodegradable'' label may be bad news for global warming

Biodegradable products are good, right? Not according to new research from North Carolina State University which shows that as they degrade these products, often labelled 'green' release a powerful greenhouse gas.

"Biodegradable materials, such as disposable cups and utensils, are broken down in landfills by microorganisms that then produce methane," says Dr. Morton Barlaz, co-author of a paper describing the research and professor and head of NC State's Department of Civil, Construction, and Environmental Engineering. "Methane can be a valuable energy source when captured, but is a potent greenhouse gas when released into the atmosphere."

In American, the Environmental Protection Agency says that only 35 percent of landfill waste is stored in methane-capturing facilities.

"In other words," Barlaz says, "biodegradable products are not necessarily more environmentally friendly when disposed in landfills."

In order for American products to be labelled as biodegradable, they must break down quickly, and it is this need that makes them so dangerous as methane is produced too quickly to be captured.

The NCSU team therefore are recommending that a slower rate of degradation is promoted.

"If we want to maximize the environmental benefit of biodegradable products in landfills," Barlaz says, "we need to both expand methane collection at landfills and design these products to degrade more slowly - in contrast to FTC guidance."

The research is published in the new edition of Environmental Science & Technology.

Top Image Credit: © Anthony Hall.