Not all “biodegradable” plastics are created equal – know what the labels mean
By Dr Ross Headifen, supporter and educator in issues concerning the proliferation of plastic waste and how to reduce it.
When 5 billion shopping bags are used in Australia each year with only 3% being recycled and 75% going to landfill, the importance of biodegradable plastics as a solution to reducing waste becomes apparent.
Certainly, refusing and reusing is preferred, which is what the ban on single use plastic bags in Australia wants to achieve. However, if you do use plastic bags but still want to reduce your environmental footprint, take a few minutes to learn what the different product labels mean so you can make the right choices.
Most importantly, be wary of any claim of being “Biodegradable” if there are no details on where it will biodegrade and why it is biodegradable.
Bioplastics – made from plant-based materials. Only a small portion of bioplastics are biodegradable, most of which require a municipal or commercial compost facility to actually biodegrade. And they cannot be recycled.
Compostable plastics – refer to “biodegradable” plastics made from plant-based materials like corn and wheat starch which will only biodegrade if composted in a municipal or commercial compost facility. Unfortunately, there are not many such facilities available or accessible. In fact, there is no infrastructure to separate compostable plastics from other waste or to transport them to such facilities, resulting in them going to landfill. “Compostable plastic” will not biodegrade in landfills as they are too cool and cannot be recycled.
Degradable plastics – has nothing to do with biodegradation and microorganisms. “Degradable” plastics use a metallic additive that sets off a slow chemical reaction and over 12-24 months will cause the plastic to fragment into little pieces. So, instead of one piece of plastic we end up with hundreds or thousands of little pieces of plastic which may not be visible, but a worse result for the environment particularly when marine animals easily consume these fragments. “Degradable” plastics cannot be composted or recycled
Landfill biodegradable plastics – incorporate an organic food source additive in the plastic at the time of manufacture. When disposed to a landfill they attract naturally occurring microbes that exist in there. The microbes seek out the food and in the process the enzymes they secrete break down the long polymer molecules where they can be digested too. The resulting products of the biodegradation are a biogas and a biomass (humus). There is no plastic residue left or any toxic constituents. “Landfill biodegradable” plastics can be recycled. They can also be composted in a municipal or commercial compost facility. Their results are verified by various ASTM testing methods.
NOTE: No plastic is good in the ocean. There are no microbes present there to biodegrade the material away.
Dr Ross Headifen is Co-founder of Biogone, Australia’s first landfill biodegradable plastic company for commercial and consumer products. He is also Vice-President of Beach Patrol, the largest volunteer group picking up rubbish across Victoria with many groups conducting school visits and community events to raise awareness about the plastic problem.