Are Biodegradable Plastic Bags As Environmentally Friendly As Reusable Shopping Bags?
While biodegradable plastic bags may seem more environmentally friendly than ordinary plastic, they aren’t the best solution for our plastic bag problem. Biodegradable bags can be made from a variety of materials, including starch-based polymers (potato, corn, wheat or tapioca starch), polyester, water-soluble polymers, polymers that degrade under light or oxidation, or a blend of any of these. Depending on the material they’re made from, biodegradable plastic bags can take much more energy to produce than polyethylene plastic.
According to a life cycle assessment of several different disposable bags conducted by the American Chemistry Council, compostable bags made of a blend of polyester, polylactic acid and calcium carbonate required nearly three times more energy and fossil fuels to produce than polyethylene plastic. Their production also resulted in more than four times the CO2 emissions as polyethylene plastic bags and nearly eighteen times the fresh water usage. These valuable resources can be spared if we reduce our consumption of all disposable bags and turn instead to reusable grocery bags.
Biodegradable plastics of any type also carry the disadvantage that they cannot be recycled with ordinary plastics. If they are thrown away, they suffer the same fate as all other trash in a landfill — they won’t biodegrade anytime soon. Some biodegradable bags can be composted and, depending on what compounds they are made of, can disappear within months, but there are only about 100 composting facilities in the US that can dispose of these bags properly. More often than not, biodegradable bags end up as litter or in landfills. Biodegradable plastic can also carry residues that are harmful to soil and animals and can cause the same environmental damage as plastic bags before they biodegrade. Biodegradable bags will not be a viable replacement for plastic bags until technology and composting programs are further developed. A more environmentally sound alternative to using an ordinary plastic bag is to carry a reusable grocery bag.
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