Image: Oxo-biodegradable plastic does however exist, and “oxo-biodegradation” is defined by CEN as “degradation resulting from oxidative and cell-mediated phenomena, either simultaneously or successively”.  

Oxo-Biodegradable Plastic

Microplastics are tiny pieces of plastic, which are being found on land, in the sea, and now even in the air we breathe. They are created by the fragmentation of ordinary plastics caused by the effects of uv light and mechanical stress.  The problem is that although these plastics are fragmenting, their molecular-weight remains too high for biodegradation, so they persist in the environment, getting smaller and smaller over a period of many decades. The answer to this problem is to make the plastics in a slightly different way, with oxo-biodegradable technology, so that if they do get into the open environment the molecular-weight of the plastic will rapidly reduce and it will cease to be plastic. It will then have become a source of nutrition for micro-organisms, who recycle it naturally, back into nature.  This technology is suitable for almost all products made with polyethylene, polypropylene, or polystyrene.

“Oxo-degradation” is defined by CEN (the European Standards authority) in TR15351 as “degradation identified as resulting from oxidative cleavage of macromolecules.”  This describes ordinary plastics, which abiotically degrade by oxidation in the open environment and create microplastics, but do not become biodegradable except over a very long period of time. Nobody makes plastic and sells it as “oxo-degradable” but this terminology is used by the Ellen MacArthur Foundation and others who wish to avoid acknowledging the existence of oxo-biodegradable plastic.  It is time for this misdescription to stop, as it is causing confusion.

Oxo-biodegradable plastic does however exist, and “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. These plastics are tested according to ASTM D6954.

A report was published in 2017 by the Ellen MacArthur Foundation and endorsed by some of the world’s largest producers of the very plastic packaging which is polluting the oceans.  It was also financially supported by the producers of crop-based plastics who see oxo-biodegradable plastics as a threat to their market-share. The Report claimed that oxo-biodegradable plastics (which they incorrectly describe as “oxo-degradable” plastics) simply fragmented into tiny pieces of plastic – but having engaged with our scientists they no longer say that.

They now admit in their May 2019 report that these plastics are manufactured so that they can degrade faster than conventional plastics and that they do become biodegradable, but they say that “it is not yet possible accurately to predict the duration of the biodegradation for such plastics.”

For that reason a broad indication only can be given as to timescale.  It is however possible to say with certainty that at any given time and place in the open environment an oxo-biodegradable plastic item will become biodegradable significantly more quickly than an ordinary plastic item.

It is not important how long a particular piece of plastic in a particular place will take to biodegrade – the importance of oxo-biodegradable technology is that it will quickly reduce the overall burden of plastic in the environment.

There is huge resistance to this technology from some of the largest companies in the world who make “bio-based plastics” and from other large companies who will not spend even an extra 1% on oxo-biodegradable technology to protect the environment from their products, which we can see with their name on them, littered all over the globe.  There has been aggressive lobbying of governments and international institutions, coming especially from Germany and Italy.

THE SCIENCE

The coronavirus has shown us that consensus among scientists is hard to find, but leaders cannot wait for consensus when decisions have to be made, because they have to weigh the evidence and form a view as to what, on balance, is the best course to take.

So it is with the environment.  Leaders know that thousands of tons of plastic are getting into the open environment every day, and that we may soon have more plastic in the ocean than fish, but what are they doing about it?  They are trying to reduce the amount of plastic we use, but some of it will still get into the open environment.

Oxo-biodegradable plastic is a technology which makes ordinary plastic biodegrade if it gets into the open environment instead of lying or floating around for decades, and it has been used successfully around the world for more than 20 years.  It has been used by the largest bakery in the western world for more than 10 years with no problems, but only a very few forward-looking governments have made it compulsory. What are the rest doing?  They prefer to encourage recycling and composting, but if they think about it for a moment these will not help them to deal with plastic in the open environment which cannot realistically be collected.

So why are they not all making oxo-biodegradable plastic mandatory, and instead allowing ordinary plastic to continue in use?  In some cases because they are under inappropriate pressure from multinational commercial interests, and in others because there is no complete consensus among the scientists.  There is however sufficient consensus to enable a decision to be made.  There is consensus on the following points:

Ordinary plastics fragment into microplastics under the influence of weathering, but for many decades their molecular-weight remains too high to allow biodegradation .

Adding a pro-degradant catalyst at manufacture reduces the molecular-weight much more quickly if the plastic escapes into the open environment.

The only environmental conditions necessary for oxo-biodegradation are oxygen and bacteria, both of which are ubiquitous in the open environment. Sunlight and heat will accelerate the process but are not essential

Bacteria found on land and sea are able to consume the low molecular-weight residues of plastic.

These residues are not toxic

There are already Standards in place which are suitable for testing oxo-biodegradable plastic. See below.

Disagreement remains about:

How long it takes before the plastic becomes biodegradable. Timescale depends on the composition of the plastic, how old it is when it gets out into the environment, and the environmental conditions to which it is exposed. Sunlight and heat are not essential, but they will accelerate the process, and it is most unlikely that a piece of plastic litter will not be exposed to one or both of these. Once initiated, the abiotic process of degradation is unstoppable unless the plastic is completely deprived of oxygen, which is impossible in the open environment.

It is known that conventional plastic fragments do not become biodegradable for many decades, but it is possible to say with certainty that at any given time and place in the open environment an oxo-biodegradable plastic item will become biodegradable significantly more quickly than an ordinary plastic item.  That is the point. – Do we want ordinary plastic which can lie or float around for decades, or oxo-biodegradable plastic which will be recycled back into nature much more quickly?  Of course, we don’t want plastic in the environment at all, but that is not the present reality.

Will it fully biodegrade? It is known that plastic whose molecular weight has been significantly reduced is much more likely to biodegrade than ordinary plastic, but we have heard no reasons from any scientist why, once degradation has commenced, it should not continue until biodegradation is complete.

In summary therefore there is sufficient consensus to enable decision-makers to conclude that oxo-biodegradable plastic is better than ordinary plastic and to decide to stop plastic accumulating in the environment, by requiring it to be oxo-biodegradable.  Delay about this is no longer an option, because thousands of tons of plastic are getting into the open environment every day.

The biodegradability of oxo-biodegradable polymers has been extensively studied and reviewed in scientific articles over more than 40 years since the publication by Professor Scott of his academic textbooks on the subject “Polymers in the Environment” – (Royal Society of Chemistry), “Degradable Polymers, Principles and Applications” (Kluwer Academic Publishers) and many peer-reviewed academic papers on this subject. In these publications Professor Scott has made it clear that oxo-biodegradable plastic will degrade and then biodegrade in the open environment very much more quickly than ordinary plastic, leaving no persistent fragments and no toxicity.

In 2018 the scientific evidence was reviewed by a distinguished former deputy judge of the High Court in England.  https://www.biodeg.org/uk-judge-find-the-case-for-oxo-biodegradable-plastic-proven/    This has been confirmed by later research published by Queen Mary University London in February 2020. https://www.biodeg.org/wp-content/uploads/2020/02/published-report-11.2.20.pdf

RE-USABLE BAGS

It is obvious that a new single-use bag or package is much less likely to spread disease than one which has been re-used a dozen times.

Re-usable bags are rarely, if ever, washed, and are often stored in a cupboard or boot of the car where germs can multiply.   Deadly micro-organisms such as Coronavirus, E.coli and Campylobacter can be transferred to food inside the bag.

With regard to their environmental credentials, scientists at RMIT University, Melbourne found that reusable shopping bags are only beneficial to the environment if they are used at least 104 times.  This is because thicker plastic bags require more plastic and more energy to produce than lightweight bags.  Also, they will create more pollution, including microplastics, if they escape into the sea or the desert at the end of useful life, unless they are made with oxo-biodegradable technology, which can be programmed to start degrading in whatever timescale is required.

However, there is a solution for those who still prefer re-usable bags. They can be made with anti-microbial technology see www.d2p.net  which can be incorporated into the polymer used for making the bags, and can also be incorporated into the laminate coating inside jute or cloth bags.

Biodeg