Michael Stephen Column Microplastics & Nanoplastics OXO Waste Management

Virgin Mobile, Defra, OXO, Microplastics, End of Life Options

Michael Stephen, an international expert on bioplastics, shares his thoughts and opinion on important issues impacting the bioplastics industry. Today, Michael writes about Virgin Mobile, Defra, Oxo-Degradable vs Oxo-Biodegradable, Scientific Evidence, Microplastics, Composting, Landfill, Recycling and Waste Management. This is a FREE article.

Virgin Mobile

Virgin Mobile should be commended for deciding to make their SIM cards with oxo-biodegradable technology.  Despite their tiny size, SIM cards need to be punched out of a credit card sized plastic sheet, which is then disposed of – this is why Virgin Mobile UAE is making the switch to oxo-biodegradable materials to reduce the impact on the planet. 

DEFRA (UK Environment Ministry)

Readers of this column will know that I have been reading through the 134 documents which DEFRA refused to disclose to me until they were ordered to do so by the Information Commissioner. These are responses which DEFRA received to their “Call for Evidence on Standards for Bio-based, Biodegradable and Compostable Plastics.”  DEFRA are still refusing to disclose five of these responses and I am still awaiting a decision of the Information Commissioner in respect of them. 

DEFRA said in their response to the consultation that “There was a clear consensus in relation to plastics containing prodegradant agents aimed at aiding the biodegradation process, which was that such technologies are unproven and likely to be a source of microplastic pollution.” 

I can now see why DEFRA wanted to conceal these documents, because I have not so far found any such consensus, and it seems clear that DEFRA had misled Parliament and the public.  There was much more of a consensus against “compostable” plastic.

Further evidence of the lack of credibility of DEFRA in relation to oxo-biodegradable plastic is a letter Felicity Buchan MP received on 16th March 2022, as one of her constituents thought that DEFRA ought to meet with Symphony Environmental’s scientists to improve their understanding of the subject. They refused a meeting, and said:

“It is always appreciated when parliamentary colleagues pass on information that may be of help to the Department. In this instance however, Defra officials are already aware of Symphony Environmental and the products they provide, so at this time, there is no need for a meeting.

To provide you with further detail, there are some concerns Defra has with oxodegradable plastics. Once the oxodegradable plastic degrades, it is not guaranteed that the resulting plastic fragments will themselves breakdown. Though there is potential for this to occur in some instances, this would be material and environment specific. In this, encouraging the use of oxodegradable plastics may inadvertently increase the presence of microplastics.

Looking at the disposal of such items is also important. Evidence suggests that oxodegradable plastics biodegrade in highly specific environments. Research has shown that these plastics do not meet the standards for compostable plastics and so are unsuitable for anaerobic digestion and composting. Furthermore, if oxodegradable plastics reach landfill, the biodegradation potential can only be accessed when they are in the aerobic (first) stages of landfill, after which the breakdown is limited.

Additionally, evidence suggests that oxodegradable plastics have limited reuse and/or recyclability potential. It has been suggested that the quality of recycled material is reduced by the inclusion of oxodegradable plastics which, in turn, reduces the recycled material’s market value. It is also understood that waste management facilities would not be able to successfully identify and remove oxodegradable plastics from their feedstock chain. Therefore, if oxodegradable plastics are not suitable for long-term reuse, recycling, composting or anaerobic digestion, have limited benefit when reaching landfill and only breakdown in specific open environment conditions, it is difficult to see where the value of introducing such materials to the waste stream would lie.

Finally, in most circumstances our preference is for plastic to be reused or recycled. This is in line with our circular economy ambitions and does not align with encouraging the use of oxodegradable plastics.”

This letter was copied to Symphony, who commented as follows:

“For the following reasons, the letter shows that DEFRA officials are not fully aware of Symphony Environmental and the products we provide, and that there is indeed a need for a meeting between our scientists and theirs.  Their muddled thinking is very damaging to a British technology.

OXO-Degradable or OXO Biodegradable?

The letter shows that DEFRA have not understood the difference between oxodegradable and oxo-biodegradable plastic. “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.

Accordingly, DEFRA are correct to say that “it is not guaranteed that the resulting plastic fragments of oxodegradable plastic will themselves breakdown.”  This is why they should ban ordinary (oxodegradable) plastics, which perform in this way, and encourage or require consumer plastics to be upgraded with oxo-biodegradable technology.

By contrast, “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.

Scientific Evidence

DEFRA ought to be aware of a really important report published in 2021 in English and French from the Oxomar project  (OXOMAR Report)

This is the most significant piece of actual scientific work (as distinct from literature reviews) conducted in recent years, and DEFRA have not even mentioned it.  Oxomar was a three-year study, sponsored by the French government, which proves beyond doubt that oxo-biodegradable plastic does biodegrade in the marine environment.  To be quite sure, the scientists exposed a sample containing carbon 13 to bacteria, and they identified carbon 13 in the bacteria themselves – proving that the bacteria had bioassimilated the material. They are writing a further report on this.

Research at Queen Mary University London has shown that the biodegradation can be up to ninety times faster than ordinary plastic. 

Report  (para. 2.3) 

“Highly Specific Environments

DEFRA are mistaken in thinking that oxodegradable plastics biodegrade in highly specific environments. As mentioned above, they do not biodegrade at all, except over a very long period of time. DEFRA are confusing these with “compostable” plastics, which are tested (according to EN13432) to biodegrade in the specific conditions found in a composting facility.

By contrast, oxo-biodegradation happens under the normal conditions found in the open environment, so the plastic does not have to be collected and taken to a composting facility or any other specific environment.


DEFRA say that “encouraging the use of oxodegradable plastics may inadvertently increase the presence of microplastics.” They will be aware that ordinary (oxodegradable) plastic will rapidly fragment into microplastics when exposed to weathering, but in the case of oxo-biodegradable plastic, the molecular structure of the plastic is modified by rapid oxidation, so that it is no longer a plastic.  It converts into a waxy substance which is biodegradable. 

The European Chemicals Agency was asked to study this subject in 2018, and they issued a Call for Evidence to which we and many others responded. They also read the reports published by the European Commission, and after ten months (30.10.18) they said that they were not convinced that microplastics were formed.  If the European Union’s own experts were not convinced we don’t see how DEFRA can be.


DEFRA do not need research to tell them that oxodegradable plastics do not meet the standards for composting. As mentioned above they are ordinary plastics, and nobody suggests that they are suitable for composting. With regard to oxo-biodegradable plastics, DEFRA should know that they have been proved according to ISO 14855 to biodegrade in compost, but this is irrelevant because they are not marketed for composting. 

In fact there is no plastic which will convert into compost.  There are plastics deceptively marketed as “compostable” but the very standards by which they are tested (EN13432 and ASTMD6400) require them to convert rapidly into C02 gas, not compost. Conversion of plastic into CO2 gas is not composting, recycling, or recovery – it is waste. For composting of plastics generally see Composting


This is also irrelevant, because neither oxodegradable, nor oxo-biodegradable, nor “compostable” plastic is designed to biodegrade in landfill. If a piece of plastic has been put into a landfill it has been responsibly disposed of, and biodegradation is neither necessary nor desirable.  In fact, since biodegradation in anaerobic conditions would generate methane (a dangerous greenhouse gas) oxo-biodegradable plastic has been designed so that it will not degrade in the absence of oxygen.


The type of plastic market as “compostable” will certainly contaminate an ordinary plastic recycling stream, and should be banned if DEFRA is concerned about this.  Oxodegradable plastic will not contaminate a recycling stream, as it is ordinary plastic.  With regard to oxo-biodegradable plastic, this has been commercially available for more than 20 years and there have been no reports that it has caused any problems when recycled together with ordinary plastic.  The type of plastic items for which oxo-biodegradable technology is used are not in any event worth recycling in economic or environmental terms, but expert studies in Austria and South Africa show that it can be safely recycled without separation. See Recycling

Waste Management

DEFRA officials seem to devote most of the time spent on plastics thinking about waste management, and we have (despite many attempts) found it impossible to focus their minds on the FAILURE of waste management.  They say that their preference is for plastic to be re-used or recycled, but how can you re-use or recycle plastic if you cannot realistically collect it from the open environment?

If it could all be collected for these purposes there would be no plastics in the ocean or elsewhere in the open environment, but everyone knows that this is not the realty.  If DEFRA officials could be brought to focus their minds on this issue they would see that the value of oxo-biodegradable plastics is not in the managed waste stream but in dealing with plastic which escapes from it. 

Nobody wants plastic in the ocean at all, but is it preferable for governments to encourage plastic which will quickly biodegrade if it does get into the oceans, or for them to continue to permit ordinary plastic, which they know will create microplastics and persist in that environment for very many decades? 


Generally, we find it unacceptable that a DEFRA Minister uses phrases such as “evidence suggests” or “it has been suggested.” It is possible to find evidence to “suggest” almost anything.  DEFRA officials cannot be relied upon to formulate policy unless they have a thorough understanding of all the evidence, including evidence from scientists working in the industry who have an in-depth knowledge of the subject. It is remarkable that they have no wish to engage with those scientists.  The Department for BEIS must also be involved here, as DEFRA’s muddled management of this subject is damaging the reputation of British oxo-biodegradable technology.”

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 Oxo-biodegradable Plastics Association.

Earlier Postings in this Column

All articles of Michael Stephen can be found here

Interview with Michael Stephen


The opinions expressed here by Michael Stephen and other columnists are their own, not those of Bioplasticsnews.com.

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