From Bioplastics to Compostables - Are They Really Better for the Environment? A deep dive.

Bioplastic, degradable, biodegradable, compostable, oxo-degradable, plant-based. Unpacking the Myths Behind 'Eco-Friendly' Labels.

We’ve all seen them - stamped on the side of your coffee cup or printed on your plastic bag or takeaway food container. Often they are accompanied by a green leaf or something similar and we are led to think we should have no guilt in using them. But they’re often not nearly as ‘green’ as they are made out to be. It’s easy to get confused and unless you do some serious research, it's unlikely you know what most of these terms actually mean. We’ve done the research for you. Let’s dive in!

Traditional plastics

Traditional plastics are made from raw petroleum based materials. They consist of chemical building blocks called monomers, linked together in very long chains called polymers. It's the size of these chains that give plastics the properties they are known for - durability, strength, flexibility. Because of this, they pose an enormous problem if they get into places they shouldn't be, like the ocean. But even these plastics are degradable - they break down into tiny fragments or powder (microplastics) over hundreds of years and in that time leach toxic chemicals into the sea and ground. Soon they may be invisible to the naked eye, but they are there: in our waterways, landfills and soils.

This is where it gets interesting because the rise of more “eco-friendly” plastics has led us to believe we have found the solution to all of our problems. They are definitely a step in the right direction but they are by no means a silver bullet. Let's take a closer look at them.

Biodegradable

If something is biodegradable it means that it can be decomposed by bacteria or other living organisms. Biodegradable plastics are made from fossil fuels but consist of additives which assist them to break down more quickly - the bad news is that this is usually into tiny microplastics which are a huge hazard to wildlife. They also often leave a toxic residue behind because they are made with inorganic materials, which makes them unsuitable for composting. A recent study of supposedly biodegradable plastic bags found them still intact after three years spent either at sea or buried underground. In fact, they were in such good shape that they were even able to hold a load of shopping!

Bioplastic

The term bioplastic suggests that an item is made from organic matter or plant-based materials and will degrade to little or nothing over a period of time, thereby eliminating pollution and posing less of a hazard to wildlife and the environment generally.  Unfortunately this idea that we can create something, use it, throw it away wherever we want and it will safely disappear, does not exist. Not even nature can engineer that! 

The conditions under which bioplastics decay safely are not clear but often they are suitable for industrial composting (and we will talk more about that in a little while). If they end up in a regular recycling bin however, they contaminate that load as they are not easily recyclable and must be separated from traditional plastics. Without proper recycling schemes in place for them and no kerbside collection, they usually end up in landfill - potentially releasing methane gas which is even more harmful to the environment than carbon dioxide.

A major problem with biodegradable plastic and bioplastics is the lack of regulation around how the terms are used. They are often incorrectly used interchangeably and the conditions required for them to break down are somewhat of a mystery. This nicely leads us into discussing compostable plastics.

Compostables

The good news about compostables is that there are certification standards which apply to their labelling. Unfortunately this is where the good news ends. Compostable plastics are specifically designed to break down into natural non-toxic components under certain conditions. These conditions are quite specific and do not normally exist in home composts. This means that they need to be sent to an industrial composting facility where the appropriate levels of heat, humidity and oxygen are present to break the items down. And whilst the production of compostable plastics is increasing, the number of industrial facilities needed to process them is not keeping up. Even if you had a facility nearby, the vast majority of kerbside collection programs do not have a compost collection system (and the ones that do mostly don’t allow home compostable packaging to be included due to the chemicals in waterproofing barriers), let alone industrially compostable! And just like bioplastics, placing these items into any of the ordinary recycling bins is considered contamination and results in an entire batch being sent to landfill. And so the story repeats itself. More waste, releasing harmful gas into the atmosphere.

New Solutions, New Challenges

Crucially, the terms compostable and biodegradable and bioplastic imply absolutely nothing about how the material will break down in the natural environment. These plastics usually require special treatment and are not designed to degrade without it, which means when they end up in the environment as litter they can be just as harmful as regular fossil fuel based plastics. 

The ubiquity of plastics in Australia and around the world means in order to end our dependence on fossil fuels we do need to make them from biological sources. The plants that are grown in order to manufacture bioplastics capture carbon so there is no net carbon increase when they degrade. So whilst there is evidence that the production of these plastics has a slightly less negative impact on the environment than the production of traditional plastics, new problems emerge - from the clearing of land that would otherwise be used for crop growing for food, through to the pollution that is generated from fertilisers, pesticides and the chemical process required to turn organic material into plastic.

The Takeaway

There are a number of initiatives in action around the world that are making strides towards “greener” bioplastics. There are companies producing plastic from methane gas, organic waste, algae, the list goes on. All of these show promising signs so it is clear that more sustainable plastic alternatives exist and will likely exist in the future. But without proper consultation with industry and government to develop the infrastructure required for their manufacture, collection and disposal on a large scale, they are not a sustainable solution. Truly green plastic needs to consider the product’s entire life cycle including the social conditions under which the materials are actually produced. In addition, we have to ask ourselves: Is single use ever really worth it? Perhaps there will always be a need for it and this could be where green bioplastics show their value. Or perhaps as a society we will change our attitude altogether and realise that our love for single use is unrequited.