Bioplastics

Bioplastics

Are bioplastics the solution to our plastic toxicity and pollution problems? Are they safe, viable alternatives to traditional plastics? It’s simplistic and inaccurate to think that replacing all the traditional plastics with bioplastics that have equivalent properties and are completely biodegradable is going to happen right away, but things are moving. The world of bioplastics is new and complex and it is growing fast. They currently account only for about 1 percent of global plastics production.

We think bioplastics are one part of the solution—the core solution is preventing plastic use and demand in general and reducing plastic production at the source—but only under certain conditions that prevent us from ending up with the same or even worse problems than we are faced with in dealing with traditional fossil fuel-based plastics. What do we mean?

Well, some bioplastics are made with fossil fuel–based plastics. Some are not biodegradable or recyclable. Some contain a slew of toxic chemical additives. To understand what we’re getting at here, you need to have a basic understanding of bioplastics. So, take a deep breath, and here goes...

What exactly are bioplastics? Bioplastics can be broadly defined as plastics that are bio-based or biodegradable, or exhibit both these properties. What in the world does that mean? Don’t worry, we’ll explain.

Let’s get some bioplastics-related terminology straight—the real definitions of words you might have heard bandied about in the media or seen on product labels: bio-based, biodegradable, degradable and compostable. You can think of these words as describing different stages and aspects of the life cycle of certain bioplastics, because they don’t necessarily apply to all bioplastics.

Bio-based focuses on the “beginning of life” of the product, that is, the origin of what the plastic is made from. Bio-based plastics are made, at least in part, from renewable, naturally occurring materials, usually plant biomass—such as corn/ maize, wheat, potatoes, soy, tapioca, coconut, cassava, sugar cane, wood and pine needles—but also more adventurous things like fungi (mushrooms), shrimp shells or insect bodies. This is in contrast to traditional fossil fuel–derived plastics made from non-renewable carbon sources such as petroleum, natural gas or coal. Upshot: in bioplastics, the carbon source is natural and renewable.

Biodegradable refers to the “end of life” of the plastic; that is, what happens to the product when disposed of after its useful life. A bioplastic product is considered biodegradable if it breaks down completely in the natural environment through the action of naturally occurring microorganisms such as bacteria, fungi and algae. These tiny microorganisms are able to use the elements of the bioplastic, principally the carbon and nitrogen, as food. Note that to be biodegradable, there is no requirement for the plastic to break down in a specific amount of time, nor that it leave no toxic residue. But the breakdown must be complete within a reasonable amount of time (about one growing season); not partial and not “eventually.

Degradable means that the plastic will undergo a significant change in its chemical structure under specific environmental conditions resulting in a loss of some properties. Essentially, it means the plastic is capable of breaking down into smaller pieces. As you can tell, it’s rather meaningless as a product marketing ploy because pretty much any and all plastics are capable of being broken down into smaller pieces. And given the global microplastics problem we are faced with, making plastics easier to break down is not a good thing if the plastics in question are in whole or in part fossil fuel–derived.

There are catchy twists on this one: photodegradable (capable of breaking down by sunlight) and hydrodegradable (capable of breaking down by water). And then there’s oxo-degradable or oxo-biodegradable (capable of breaking down by exposure to oxygen, i.e., air), which are in a whole suspicion-raising category of their own: they are simply traditional plastics that are chemically altered to break down into smaller pieces faster. Note for now that fossil fuel–based plastics are degradable, but not biodegradable. Bioplastics are degradable, and may be biodegradable.

Compostable also refers to a bioplastic’s “end of life” and, in particular, whether or not it will biodegrade in a composting environment. ASTM International (formerly American Society for Testing and Materials) and the International Organization for Standardization (ISO), the two main international standard-setting bodies, define a compostable plastic as one that “undergoes degradation by biological processes during composting to yield carbon dioxide, water, inorganic compounds and biomass at a rate consistent with other known, compostable materials and leaves no visually distinguishable or toxic residue.”

A couple of key distinctions to make with this added layer of knowledge: A bioplastic may be biodegradable, but not compostable; all compostable bioplastics are biodegradable. Upshot: To be compostable, a plastic must break down completely to basic natural substances and leave no trace of anything toxic.

So, if a takeout food container is labeled “compostable,” I can just throw it in my home composter and look forward to its harmless nutrients feeding my new crop of homegrown arugula next season, right? Not necessarily. There are two broad categories of composting: that home composter in your backyard, or a large-scale industrial composting facility.

Commercial composting facilities have set levels of heat, aeration and moisture to maximize the activity of the oxygen-requiring microorganisms breaking down the compost. A key criterion for a plastic to be called compostable according to most international standards is that 60 percent of the resin biodegrade within 180 days. And a typical industrial composting process runs for twelve weeks with temperatures constantly above 122°F (50°C).

Home composting is obviously less controlled and generally it will take much longer for things to break down. But some bioplastics are home compostable, and as a general rule, home composting is one of the best ways to significantly decrease your organic waste. If you can find some way to set up a home composting system, it will play a key role in your personal waste reduction.

Both of these composting methods are in contrast to a landfill, which is an anaerobic (oxygen-free) environment. In a landfill, bioplastics—or pretty much anything, for that matter—will not readily break down if not exposed to oxygen. And the bioplastics in a landfill that do break down will cause release of the potent greenhouse gas methane, which is produced by the anaerobic bacteria breaking down the material.

BASIC TIPS FOR DEALING WITH BIOPLASTICS

Be wary of claims that include the words “natural,” “bio-based,” “plant-based,” “biodegradable” and “compostable.” Ask the manufacturer for proof to back up claims.

Avoid oxo-biodegradable products, which are simply conventional fossil fuel-based plastics chemically altered to break down into smaller pieces faster.

Try and determine exactly what kind of bioplastic resin the product is made of, and if it is not in one of the categories we have mentioned above, try to find out more about it by contacting the manufacturer and asking if it is bio-based (if so, what percentage?), if it is fully biodegradable, if it is compostable (if so, in an industrial or home composter?). Ask what additives have been mixed with the resin to make the final product (e.g., fillers, flame retardants, softeners and colors).

Look for a third-party certification label to determine if the product actually is bio-based, biodegradable and compostable (and if it is compostable, whether in an industrial composting system only, or a home composter as well, or in a freshwater or marine environment).

Even if a product is made with a bioplastic resin that you know is certified compostable, be sure to check if there is a certification label for the final product. The core resin might be compostable, but the processing of it to make the final product could have included additives that now prevent it from biodegrading fully and being compostable.

Check if your municipality accepts bioplastics for recycling or composting, and if so, which ones and in what types of products. If your municipality does not, then you may be able to find a facility near you using Biocycle’s online database of composting, anaerobic digestion, and organics collection services in the United States and Canada (www.findacomposter.com). Note, however, that organic composting services will likely not accept bioplastics.

A useful resource is the Sustainable Biomaterials Collaborative (www. sustainablebiomaterials.org/), which provides all kinds of information on bioplastics.

Another useful resource is the Biodegradable Products Institute (BPI) (www.bpiworld.org), which provides an excellent database of compostable products currently on the market. If you don’t see a label, or just want more information on the biodegradability or compostability of a product, this is an excellent place to start.

Most important of all: Try to avoid all disposables, but if you absolutely must use a disposable item, try to make it a bio-based, home compostable one with biodegradable additives.

IMPORTANT NOTES: While we strive to provide as accurate and balanced information as possible on our website, Life Without Plastic cannot guarantee its accuracy or completness because there is always more research to do, and more up-to-date research studies emerging -- and this is especially the case regarding research on the health and environmental effects of plastics. As indicated in our Terms & Conditions, none of the information presented on this website is intended to be professional advice or to constitute a professional service to the individual reader. All matters regarding health require medical supervision, and the information presented on this website is not intended as a substitute for consulting with your physician.

Throughout our website, some technical terminology is used. In the interest of making the articles accessible and not too long, dry, or complex, technical terms may be hyper-linked to more detailed explanations and relevant reference material provided in Wikipedia. Please keep in mind that Wikipedia articles are written collaboratively by volunteers from all over the world and thus may contain inaccuracies. Life Without Plastic makes no guarantee of the validity of the information presented in Wikipedia articles to which we provide links. We suggest you read the Wikipedia General Disclaimer before relying on any information presented in a Wikipedia article.

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