Would using biodegradable plastics solve the world's plastic problems?

Question

If plastic is the problem, is next-gen biodegradable plastic the solution and will prevent plastic pollution?

Answer 1

Not all alternative plastics are the same and are sometimes, mistakenly, referred to as each other. It is useful to question the supplier of a product whose packaging is referred to with these terms - what exactly the material is made of, what exact conditions it will decompose under, what elements it will decompose into, how long decomposition will take, how to dispose of it, etc.

 

These are the different alternative plastics and what they mean:

• Biodegradable Plastic - This is not a type of plastic but a feature. The official definition is “capable of undergoing decomposition into carbon dioxide, methane, water, inorganic compounds, or biomass in which the predominant mechanism is the enzymatic action of microorganisms, that can be measured by standard tests in a specified period of time, reflecting available disposal condition”.
• Bio-based or biobased plastic - Plastic synthesised from biomass or renewable resources.
• Bioplastic - This term can be used for biodegradable plastic produced from fossil materials or bio-based plastic or a combination of both.
• Compostable Plastic - It meets EN13432 or a comparable standard for compostable packaging so that the material decomposes/biodegrades in industrial composting conditions. Materials that meet an appropriate home composting standard can be composted in home composting systems.
• Degradable plastic - Fragments into smaller pieces and may even degrade to residues invisible to the naked eye.
• Oxo-degradable plastic or oxo-plastic - Conventional plastic which includes additives to accelerate the fragmentation of the material into very small pieces, triggered by UV radiation or heat exposure.

 

Let's go over the different problems with conventional plastics and if alternative plastics solve them:

• There are so many different types of conventional plastics that it is hard to distinguish between them and determine how to dispose them. There are many different types of alternative plastics and it is hard to distinguish between them and determine how to dispose them.
• Conventional plastics don't decompose easily and when they do they break down into microplastics. Most alternative plastics are designed to decompose in industrial environments only, although some may in home composting. Some are made of petrochemicals, including some home compostable ones, so could leave toxic residues or microfibres.
• There are not enough facilities to recycle different types of conventional plastics. Alternative plastics are rarely recyclable, although they may be decomposable. Mixing them with conventional plastic recycling contaminates that too. There are currently very few facilities in most parts of the world to decompose alternative plastics (most UK recycling systems do not accept them).
• Conventional plastics do not decompose in landfill environment. Alternative plastics do not decompose in landfill environment either. And slight decomposition could lead to the release of the greenhouse gas methane, due to conditions in an anaerobic environment.
• Incinerating conventional plastics generates toxic chemicals. As many alternative plastics are made of petrochemicals, so may incinerating them.
• Conventional plastics released into the ocean are harmful to marine life. The ocean is not an ideal environment for breaking down alternative plastics. When released into oceans they will not break down easily and are harmful to marine life.
• Conventional plastics poison our food chain when organisms like plankton eat them. As many alternative plastics are made of petrochemicals, so may they.
• Conventional plastics are harmful to wildlife when wildlife gets entangled in them or feed on them. Alternative plastics will do the same.
• Conventional plastics involve extracting fossil fuels. As many alternative plastics are made of petrochemicals, so will they. For others, there is high use of energy during production, which usually comes from fossil fuels.
• Production of conventional plastics is harmful to the environment. There is usually high use of energy and water during production of alternative plastics. Some lead to deforestation. Some affect the food supply when land that could be used to grow food is used to grow their raw materials. Industrial farming practices for raw materials release chemicals into water bodies that kill aquatic organisms and increase acidification.
• Conventional plastics leach out toxic chemicals and may affect human health. As many alternative plastics are made of petrochemicals, so may they. Chemicals may also be added to a bio-based plastics to add strength, prevent wrinkling, or confer breathability, and these chemicals will be released on degradation.
• Conventional plastics contribute to climate change, see “How Does Plastic Affect Climate Change?” (OneSharedEarth, 2020). Alternative plastics also contribute to climate change, see “What Impact Do Alternative Plastics Have on Climate Change?” (OneSharedEarth, 2020).

 

According to “Plastic & Climate: The Hidden Costs of a Plastic Planet” (Center for International Environmental Law, 2019):

False solutions (such as bio-based and biodegradable plastic) fail to address, or potentially worsen, the lifecycle greenhouse gas impacts of plastic and may exacerbate other environmental and health impacts. 

 

So it is clear that alternative plastics do not solve the world's plastic problems.

  

Bibliography

DiGregorio BE, “Biobased Performance Bioplastic: Mirel” (2009) 16 Chemistry & Biology 1

“REPORT FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT AND THE COUNCIL on the Impact of the Use of Oxo-Degradable Plastic, Including Oxo-Degradable Plastic Carrier Bags, on the Environment” (Europa.eu, 2018)

Song JH and others, “Biodegradable and Compostable Alternatives to Conventional Plastics” (2009) 364 Philosophical Transactions of the Royal Society B: Biological Sciences 2127

Tokiwa Y and others, “Biodegradability of Plastics” (2009) 10 International Journal of Molecular Sciences 3722

“Plastic & Climate: The Hidden Costs of a Plastic Planet” (Center for International Environmental Law, 2019)

Tereza Pultarova, “Could Next-Gen Biodegradable Polymers Help Solve the Plastic Problem?” (Theiet.org, 2019)

Thomlinson I, “Plastic (Not) Fantastic: Why Even Biodegradable Plastic Can Still Harm the Environment” The Independent (2019)

“Understanding Plastic Packaging and the Language We Use to Describe It” (WRAP)

“Why Is Plastic Harmful?” (Plastic Pollution Coalition, 2018)

Answer 2

This is quite a complex question to answer. Firstly we need to understand what the biodegradable plastics are. There are two main categories:
1.Bioplastics, which are made from natural materials like corn starch;
2.Biodegradable plastics that are made like regular plastics using petrochemicals that are engineered to break down quickly
The most common material used in bioplastics is Polylactide acid (PAL) produced out of corn kernels. It looks and behaves almost the same as polyethylene (PE) and polypropylene (PP). Production of it uses only a third of the energy required for traditional plastics. It is fully compostable.
Unlike bioplastics, biodegradable plastics are made of normal (petrochemical) plastics and don't always break down into harmless substances: sometimes they leave behind a toxic residue and that makes them generally (but not always) unsuitable for composting.
They may seem like the perfect solution but it is not that simple. Bioplastics for example, when they decompose on the landfill may still produce methane, which is a very powerful greenhouse gas. Because they look like PP and PE they may be easily mistaken with them and enter the traditional plastics' recycling stream which becomes contaminated. Also production of them requires the same resources as we need in agriculture: land, water, energy, pesticides etc. There is a huge risk of the food prices going up when farmers switch from growing food to bioplastics and biofuels. Also some bioplastic and biodegradable plastics require relatively high temperatures to decompose, which means it may take years for them to degrade.
In my opinion the volume of plastics we consume can't be replaced with the biodegradable options. We need to rethink our consumer behaviours, our addiction to packaging and convenience. They can be used as a last option but only reducing our use of any plastic is the best for the planet.

Bibliography

“Biodegradable Plastics: Are They Better for the Environment?” (Futurenergia.org, 2019)

Woodford C, “Bioplastics and Biodegradable Plastics - How Do They Work?” (Explain that Stuff, 2019)