Plastic Promises

Biodegradable plastics are eco-friendly, but only if they are disposed of properly.

By Kimberly Button

May 2013


Chinese take-out seems less like a guilty pleasure when the container claims it is “100% bio­degradable.” Add to that the satisfaction from using disposable cutlery made from corn-based plastics and this to-go meal doesn’t seem so bad. Or is it?

Bioplastics, those made from plant-based materials or that will biodegrade in a short time, are supposed to ease the environmental impact of plastic. In fact, they might just be lulling consumers into a false sense of security.

The problem with plastics is that more than 30 million tons of the material wound up in US municipal solid waste in 2010 alone, according to the Environmental Protection Agency. Less than 14% of plastic containers and packaging managed to be recycled.

Plastics are typically made from petrochemicals, such as oil and natural gas. If not recycled, they clog up landfills, taking on average 1,000 years to fully decompose. However, plastics can also be made from plant-based materials that can decompose relatively quickly. Rapidly disappearing plastics made from easily renewable materials sounds like the ideal solution.

But it’s not that easy.

It turns out that the world of bioplastics can be quite confusing. Just like the word “natural” doesn’t really mean too much in marketing claims when shopping for food, the terms “biobased,” “compostable” and “biodegradable” can take on all sorts of different meanings, too.

Standards and Ambiguity

Bio-plastics are made from plant-based materials such as corn or starch, rather than fossil-based carbon sources, according to the US Composting Council’s (USCC, www.compostingcouncil.org) “Compostable Plastics 101” report. But these new-look plastics might not easily biodegrade.

Compostable plastics must adhere to guidelines set by ASTM International, a standards association, so they degrade at a rate consistent with other compostable materials.

The term biodegradable, though, is ambiguous. Plastics that biodegrade might not be compostable, meaning that they can’t be disposed of with other trash meant for the compost bin. The length of time that it takes to biodegrade is subjective, too.

A bottle made from petroleum products will eventually biodegrade. The difference, however, is that the petroleum-based bottle might take hundreds of years to degrade, while the plant-based bottle might take a few months. The USCC explains that “the term biodegradable is essentially meaningless without being tied to a specific timeframe and environment.”

Consumers are not the only ones scratching their heads over whether their starch-based disposable spoon can be composted or recycled or should just be thrown in the trash heap. Industry leaders are trying to come to terms with the ever-changing technology, too.

Tom Szaky, chief executive of TerraCycle, a company that collects hard-to-recycle products and converts them into other materials and products (www.terracycle.com), was surprised when he found out firsthand how difficult biodegradable plastic can be to dispose of.

When Frito-Lay’s original biodegradable Sunchips bags were pulled from store shelves in 2010 because consumers complained of the noise that they made, TerraCycle received 100 truckloads of packaging.

“We called every single composting organization in the US, about 100 of them, and asked if they’d be interested in a million or two million pounds of PLA [a corn-based plastic] and if they’d be interested in integrating it into their compost pile,” Szaky said. “Without exception every composter said no.”

With varying types of materials used in the many plastics labeled biodegradable, the industries responsible for disposing of the products are finding that they cannot accept all bioplastics, even if they are promised to degrade. In certain instances, the materials will actually diminish the quality of compost or recycled plastic.

Wading Through

As the composting and recycling industries work to create uniform standards to make the process of disposal easier, keep the following tips in mind when buying a bioplastic with the expectation that it will soon disappear.

Read labels. Is the product simply made from plant-based materials? Does it state on the packaging that the product is compostable or biodegradable in a certain amount of time?
Do not assume that bioplastics will break down in your home compost bin. Joe Lamp’l, host of PBS’ “Growing a Greener World” (www.growingagreenerworld.com), warns that “biodegradable plastics in theory are a great idea, but in practice it’s difficult for an average homeowner to achieve and sustain sufficiently high temperatures for this to happen properly.” Frito-Lay also admits that it takes high heat for a Sunchips bag to decompose. Lamp’l says “commercial composting facilities are best suited for these types of plastic to actually biodegrade.”

Throwing a bioplastic product in the trash does not mean that it will eventually biodegrade somewhere. Certain environmental conditions are needed to get the job done, such as exposure to sunlight or water or high heat. The product must be disposed of as intended in order to degrade.
Recycling and composting rules vary in every community. Contact your municipal solid waste department and ask how—and if—they accept bioplastics for disposal.

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