Bioplastic? Biodegradable? Oxo-degradable? Compostable?
We have started to see a rise of alternative or “green” plastics and packaging now that environmentalism and sustainability have become a larger focus in mainstream society. Nowadays it seems like most packaging has some sort of symbol or label that indicates it is different from conventional plastic. Terms like “bioplastic,” “biodegradable,” or “compostable,” are frequently used and in the rare case, “oxo-degradable.” It is easy to feel confused and overwhelmed when presented with all these terms that seem interchangeable, and not really know what exactly they mean to you, the consumer. Here are some helpful tips to understand what these terms mean, how to properly dispose of them, and what we can do to combat plastic waste.
What Does Bioplastic Mean?
To put it simply bioplastic refers to the actual material of the plastic, not necessarily how it will break down in the environment. Bioplastics are made from renewable resources such as plant materials or agricultural byproducts instead of the traditional petroleum. However, not all bioplastics are made equally, meaning that some may biodegrade naturally, others need some sort of composting facility, and some might even take hundreds of years to biodegrade. This is in part due to the fact that plastics made mostly or entirely from fossil fuels can potentially be labeled as “bioplastic” or “biobased.” There is a chance that plastic that is 100 percent made from fossil fuels could be considered bioplastic if it is biodegradable.
Typically bioplastics generate fewer carbon emissions in the beginning of their life cycle in comparison to traditional plastic, since they are made from renewable sources. However, bioplastics have the potential to negatively impact the environment. If the demand for bioplastics increases the need for land to grow the crops could potentially lead to water shortages, desertification, the loss of habitats and biodiversity, increase in monoculture cropping and the use of pesticides. Bioplastics are still plastics, and just because they are made from renewable sources or have the possibility to biodegrade in specific conditions does not mean they are environmentally friendly.
What Does Biodegradable Plastic Mean?
Biodegradable refers to any product that breaks down into natural elements such as carbon dioxide and water vapour by other organisms in the environment. Generally, biodegradable products break down faster than traditional plastics, roughly three to six months. However, BPI (Biodegradable Products Institute) suggests that the term biodegradable doesn’t have a time frame attached to it and that as long as the material eventually breaks down it can be labeled as biodegradable. As promising as the term sounds, it is often just superficial and can contribute to “greenwashing.” It is incredibly hard for manufacturers to guarantee how long it’ll take for biodegradable plastics to actually break down in different environments. According to one study, the term “biodegradable” is often just a label with no proof of degradation tests presented. When the degradation process is studied, the conditions are often extreme (high heat, low/high pH values) and not environmentally realistic. Thus, it is actually quite difficult to properly dispose of biodegradable plastics and packaging. Biodegradable plastics will still contribute to plastic pollution if they are lost or littered, since they won’t actually break down as quickly as suggested or completely in the natural environment and thus harming wildlife and ecosystems.
What Does Oxo-Degradable Plastic Mean?
Oxo-degradable refers to conventional plastics like polyethylene mixed with a metal compound that makes them break down faster, specifically in the presence of oxygen. Unlike biodegradable or compostable plastic, it hasn’t actually been proven whether oxo-degradable plastic is truly biodegradable and it is feared that it actually accelerates microplastic pollution. This has led some countries to consider banning oxo-biodegradable packaging. Common products that are categorized as oxo-degradable are: single-use shopping bags, disposable gloves, foam plates, cups, cutlery and some plastic bottles.
What Does Compostable Plastic Mean?
Compostable refers to any product that breaks down into natural elements but ONLY in a compost setting. This means that there needs to be large amounts of microorganisms and heat to fully break down. There is also a specific time frame that is determined by each individual composter and their operational requirements. Compostable plastics are often made out of polylactic acid (PLA) or Ecoflex, a biodegradable polyester that is certified compostable. There are some starch based blends as well. PLA under the right conditions breaks down to carbon dioxide, water and compost, and does not produce microplastics. Some common products are disposable drinking cups, clamshell containers, compost bags and plastic cutlery. Compostable plastics and packaging is most effective in the food industry. Ideally, it has the potential to reduce the amount of plastic in the landfill, prevent recycling from being contaminated by food, and making sure food waste is returned to the soil and not left to rot in the landfill, where it will release methane.
However, compostable plastics do present some issues such as:
- Compostable plastics are often not designed for home composting systems, like backyard composts. They are tested in large-scale, commercial or industrial composting facilities, which can produce way more heat and are more carefully managed. Compostable plastic needs really high heat and a large amount of oxygen to break down.
- Many municipalities do not have access to commercial composting facilities that can handle compostable plastics.
- Many industrial composting facilities still struggle to accept compostable plastic. Even Calgary’s compost facility does not accept biodegradable or compostable food packaging.
- Often compostable plastic looks nearly identical to non-compostable plastic, making it difficult for composters to sort out the contaminated plastic.
- Certifying products as compostable is a taxing, expensive process and frustrating when products can’t actually be composted by consumers.
- Compostable plastics are a problem for most recycling facilities. It is prone to cracking and breaking apart, and it looks like easily recycled PET plastic and, if missorted, could contaminate bales of recyclable plastics.
So, how do we properly dispose of these “green” plastics?
Even though the City of Lethbridge has approved a curbside green cart program that will be city-wide in 2003, we still won’t be able to compost compostable plastics. As mentioned earlier, Calgary’s facilities don’t accept biodegradable or compostable plastics. Although they are marked “compostable” the cutlery and clamshell containers won’t break down quick enough for Calgary’s composting process and contaminates the finished compost product. When the green cart program is finally introduced city-wide the best course of action is to follow the guidelines laid out by the City’s waste and recycling centres to ensure that the waste is getting disposed of properly.
- When in doubt, throw it out. When we place these alternative plastics into recycling or composting bins they contaminate the processing stream and ultimately the final products. Compostable plastic won’t break down enough when composted, and it’ll break down too much when recycled. Compostable plastic also looks too similar to traditional plastic that there is higher potential for traditional plastic to accidentally make it into the composting stream, which will contaminate the final product and render it unusable – adding more things to the landfill.
- Biodegradable containers are not recyclable and should not go in your curbside bin.
- Reuse your bioplastic or biodegradable containers over and over again, and then either save them for when industrial or commercial composting is here or throw them out. This reduces their carbon footprint ever so slightly.
- Look at the fine print on packaging for possible instructions to proper disposal, such as home compostable or industrial compostable. Always look for BPI certification or other third party certification on compostable products.
What can we do about “green” plastics?
In the end, the best thing to do is reduce your plastic consumption. All the alternative or “green” plastics are complex and have created difficulties not only for the consumers but also manufacturers and composting facilities. If we can reduce the demand for single-use plastics and plastics in general, it will be the best course of action.
If you want to learn more about plastics in our world listen to Plastisphere: A podcast on plastic pollution in the environment hosted by Anja Krieger and read her article “Are Bioplastics Better for the Environment Than Conventional Plastics?”