GREEN DOT
An American organisation called Green Dot (which promotes vegetable-based plastic) have published what they call “A straightforward explanation of biodegradable vs. compostable vs. oxo-degradable plastics.”
It is far from straightforward.
They say that “A major source of confusion is the difference between three terms: biodegradability, compostability and oxo-degradability, but they add to the confusion themselves by saying “whenever we claim a material is “biodegradable,” we are referring to the compostability standards set forth in ASTM D6400 and EN 13432.”
It is actually deceptive to claim that a plastic which complies with those standards is “biodegradable,” because the public would expect it to biodegrade under normal conditions in the open environment. However, as Green Dot concede, these plastics are designed to biodegrade in the special conditions found in an industrial composting facility.
Green Dot themselves admit that “claiming that a plastic is “biodegradable” without any further context (i.e., in what timeframe and under what environmental conditions) is misleading to consumers.”
It is also deceptive to describe these plastics as “compostable” when those very standards require the plastic to convert into CO2 gas, not compost. The correct description would be “Biodegradable in an industrial composting facility.”
They then offer a “quick note on oxo-degradable plastics,” causing further confusion by failing to distinguish between oxo-degradable and oxo-biodegradable.
They say “they are neither a bioplastic nor a biodegradable plastic, but rather a conventional plastic mixed with an additive in order to imitate biodegradation.” These plastics “quickly fragment into smaller and smaller pieces, called microplastics, but don’t break down at the molecular or polymer level like biodegradable and compostable plastics. The resulting microplastics are left in the environment indefinitely until they eventually fully break down.”
This is a correct description of oxo-degradable plastics, except that they do not contain an additive to imitate biodegradation.
“Oxo-degradation” is defined by CEN (the European Standards authority) in TR15351 as “degradation resulting from oxidative cleavage of macromolecules.” This describes ordinary plastics, which abiotically degrade by oxidation in the open environment and quickly create fragments, but do not become biodegradable except over a very long period of time. This is why oxo-biodegradable technology was invented.
“Oxo-biodegradation” is defined by CEN as “degradation resulting from oxidative and cell-mediated phenomena, either simultaneously or successively”. This means that the plastic degrades by oxidation until its molecular weight is low enough to be accessible to bacteria and fungi, who then recycle it back into nature. See “Why biodegradable?” Why biodegrade?
Green Dot say “Ultimately, better end-of-life disposal of bioplastics strengthens their environmental value proposition of diverting organic waste from landfills, reducing greenhouse emissions and ensuring the sustainable consumption of resources.” This is itself deceptive, because they do not do any of those things. See Composting
OECD
I see that they want a trillion dollar “investment” to end plastic pollution, essentially by pumping public money into plastics recycling, which does not pay for itself because it makes no sense in economic or environmental terms to recycle PE or PP from packaging applications – which is the type of plastic most often found in the environment. See Recycling
I can think of better ways to spend a trillion dollars of taxpayers’ money. We can certainly improve waste management, but we could make an enormous impact at little or no extra cost, simply by making this type of plastic with oxo-biodegradable technology which is already available. Then, if it still gets into the open environment, it will quickly biodegrade, leaving no microplastics or harmful residues.
UNEP
The third negotiating session on a global treaty to curb plastics pollution began in Nairobi with a stark message.
“Nature is suffocating — gasping for breath,” declared the Executive Secretary at the start of the opening plenary. “All ecosystems, terrestrial and marine, are under threat from plastic pollution. Not only vulnerable and endangered species are at risk, but all diversity of life on our planet hangs in the balance.”
This is a gross exaggeration, and if delegations take notice of this kind of emotional rhetoric we will end up with a Treaty that does a lot more harm than good.
Michael Stephen
Michael Stephen is a lawyer and was a member of the United Kingdom Parliament, where he served on the Environment Select Committee. When he left Parliament Symphony Environmental Technologies Plc. attracted his attention because of his interest in the environment. He is now Deputy Chairman of Symphony, which is listed on the AIM market of the London Stock Exchange, and is the founder and Chairman of the Biodegradable Plastics Association.
Earlier Postings in this Column
All articles from Michael Stephen
Interview with Michael Stephen
Questions and Answers on OXO-Biodegradability
Disclaimer
The opinions expressed here by Michael Stephen and other columnists are their own, not those of Bioplasticsnews.com