Leisha Duncan from Boomerang Alliance interviewed Dave West on biodegradable plastic. Is it fact, or fiction?
By Leisha Duncan, September 2016
The production and the disposal of one of the world’s most essential and prevalent products – plastic – has been causing waves recently. With the fact that plastics never truly disappear and the increasing awareness of the detrimental effects that plastics are having on our environment, there has been an increase in the development of alternatives.
The impact that conventional plastics have on the world’s oceans is devastating, from entanglement and ingestion, to acting as sponges filled with toxins. The idea of having an environmentally friendly, biodegradable plastic sounds like the end to the problem of plastics in our oceans, right?
The range of materials that are commonly known as bio-plastics represent a suite of alternatives, and for the purpose of this blog we will be referring to bio-plastics as an umbrella term for those alternative plastics known as degradable, biodegradable (in landfill), oxo-biodegradable, and compostable plastics. They are defined as follows:
Dr Ross Hedifen provides a fantastic outline of the differences between the three main types of bio-plastics (see website). Here Dr Ross categorises biodegradable plastics as landfill biodegradable plastics and compostable plastics as bio-plastics, providing an outline of their production, how the different plastics breakdown and the specific differences that are important to how they should be used.
“Bioplastics are often touted as green plastics due to their plant origins but they are no more green than a conventional plastic if the bioplastic is not sent to a commercial compost facility.”
While there is no doubt that bio-plastics are an important innovation and a key long term aspect of any solution to the problem of plastic, they are not a viable solution to marine plastic pollution as of yet. But that doesn’t mean we should reject them entirely, especially in packaging and products that aren’t likely to end up in our waterways. Nova a website managed by the Australian Academy of Science provides succinct and informative resources outlining the future of plastics, providing a great overview of bio-plastics and their environmental pros and cons.
Put simply, so-called ‘bio-plastics’ substitute for the traditional fossil fuel based plastics that are proliferating our oceans.
So do bio-plastics biodegrade? Do they disappear from the environment? Unfortunately, to date bio-plastics are not truly biodegradable, and at best will only break down through multi-million dollar industrial composting facilities commonly referred to as bio-reactors or need micro-organisms, such as bacteria, fungi, and algae, or require specific controls over factors like temperature, moisture, oxygen, and pH. (Kale, et al., 2007., UNEP, 2015)
Because bio-plastics have been designed to biodegrade in these complex terrestrial conditions - which is not replicated in marine environments - any level of natural biodegradation of bio-plastics is much slower (UNEP, 2015). In addition to this, the limited infrastructure for recycling and composting means most bio-plastics end up in landfill (Kale, et al., 2007) which often enables these plastics to eventually find their way into the ocean.
Similar to conventional plastic, bio-plastics can contain heavy metals and also fragment which occurs when the plastics are exposed to UV light (photo-degradation) and abrasion (the sandpaper like effect caused as plastics are sucked through storm water drains or along our beaches. Although the breakdown of bio-plastics is claimed to be a primary benefit within terrestrial environments in marine environments the reality is they are simply fragmenting plastic packaging into ‘bite size’ pieces of plastic that are readily consumed by marine wildlife (Townsend, Committee Hansard, 2016).
We welcome the advent of genuinely biodegradable and non-toxic plastics that do not require complex infrastructure, but the fact is that the current range of bio-plastics are not a viable solution to marine plastic pollution.
Government and the Australian Packaging Covenant should prioritise the further development of bio-plastics and their use where genuinely beneficial along their entire life cycle.
Biodegradable, compostable and the entire suite of bio-plastics are not a solution to marine plastic pollution and should not be allowed to be advanced as a solution to common litter items found in marine environments e.g. single use plastic bags, disposable coffee cups, takeaway food packaging.
- The Governments of South Australia, the Northern Territory, ACT and Tasmania should immediately modify their existing bans on single use plastic bags to prohibit substitution with bio-plastic bags in any form.
Kale, Gaurav et al. "Compostability Of Bioplastic Packaging Materials: An Overview". Macromol. Biosci. 7.3 (2007): 255-277. Web.
Dr Kathy Townsend, Committee Hansard, 10 March 2016, p. 2. (Extracted from: Environment and Communications References Committee,. : Toxic Tide: The Threat Of Marine Plastic Pollution In Australia. Canberra: Commonwealth of Australia, 2016..)
UNEP (2015) Biodegradable Plastics and Marine Litter. Misconceptions, concerns and impacts on marine environments. United Nations Environment Programme (UNEP), Nairobi.
Australian Standard (2010) Biodegradable plastics - biodegradable plastics suitable for home composting