The Michael Stephen Column

PEER-REVIEWED PAPERS

I am often asked to comment on peer-reviewed papers purporting to show that oxo-biodegradable technology does not work or creates microplastics. They look impressive but BPA scientists always find a fundamental error. For example the authors (a) have not followed the procedure described in ASTM D6954 and have sometimes not followed any standard at all. (b) have followed the wrong standard eg ASTM D6400 or EN13432 (c) did not characterise the sample before starting the test, and therefore have no idea whether it contains an oxo-biodegradable masterbatch at the correct concentration or at all (d) did not continue important parts of the test for a sufficient length of time (e) used a sample so heavily laden with stabilisers that it would take a very long time before the material became biodegradable (f) exposed the plastic under conditions unlikely to be experienced by plastic litter in the open environment.

The problem is that this faulty peer-reviewed research is then cited in peer-reviewed literature-reviews and leads policymakers to make the wrong decisions.

INTERTEK EVIDENCE

I have been reading the evidence given by Intertek to the European Chemicals Agency in 2018, which is an excellent piece of work. They say:

"Almost all the micro-plastics found in the oceans have come from the fragmentation of conventional plastics. Although conventional plastics can fragment quite quickly on exposure to sunlight and mechanical stress, the fragments remain for years at a molecular mass which is too high for biodegradation. This means that conventional plastics can persist in the ocean for decades before they become biodegradable. This is why the micro-plastics tonnage in the oceans has built up: the inflow and dwell time exceeds the outflow (outflow being disappearance due to biodegradation). If the dwell time were shorter, and/or the inflow lower, build up would not occur and the micro-plastics problem would not exist."

"The faster degradation and subsequent biodegradation of oxo-biodegradable plastics means that they enter the eco-system as waste plastic in the same way as conventional plastic, but they degrade, and then ultimately biodegrade to natural materials and are recycled back into nature in less time than conventional plastics. This means that oxo-biodegradable plastics have a shorter dwell-time in the ecosystem."

The oceanic micro-plastic problem has arisen because the dwell time of conventional plastics is too long compared to the rate of arrival of more plastics. If the dwell time were shorter (i.e. conventional plastics degraded faster) and/or the incoming flow was less, the ocean would be able to handle a certain amount of plastics. The plastic contamination would disappear from the system (through biodegradation) faster than it would arise in the system (through waste plastic reaching the ocean) and there would be no build up. It is simple, undeniable physics, little different from the physics of flow of liquids through pipes. Oxo­ biodegradable plastics, through biodegrading faster, and thus having a shorter dwell time in the system, have the potential to aid the problem rather than worsen it."

"Any improvement in the speed of degradation must be useful. Considering very approximate order of magnitude figures, if conventional plastics were considered to take say 20 to 200 years to biodegrade in the oceans, and oxo-biodegradable plastics take say 1 to 10 years to biodegrade, already the oxo-biodegradable plastics are showing potential to make a positive, rather than negative, contribution to the issue."

"Various stakeholders have offered opinions on oxo-biodegradable plastics, including raising doubts about their efficacy and even doubting the point of them. Oxo-biodegradable plastics have been criticised for:

1. Increasing the amount of plastics, which is obviously illogical. The presence or not of an oxo-biodegradable additive in a plastic does not change the amount of plastic.
2. Encouraging a throw-away society, which of course they do not. The littering and inappropriate waste management that leads to the oceanic micro-plastic problem occurs irrespective of any additives in the plastics. Much of the littering is accidental, and the kind of people who deliberately throw litter do not care whether the plastic may be a type of biodegradable plastic or not.
3. Being less desirable for re-use and recycling. Oxo-biodegradable plastics are not antagonistic to re-use and recycling. As has been demonstrated by the technical reports, and in practice over years of recycling, the tiny amounts of oxo-biodegradable additive in the system make no difference to recycling or re-use.
4. Not being supportive of the circular economy. There is a clear theoretical benefit to a circular economy. However, that is a different issue from the current harsh reality of micro­ plastic pollution. If society wished to eliminate anything that is not supportive of the circular economy, it should first stop burning oil, which is a non-circular threat to sustainability that is orders of magnitude greater than the amount of oil going into making useful products such as plastics. The material used to make plastics is in any event an inevitable by-product of the process of making fuels, and the same amount of oil would be extracted from the ground if plastics did not exist.

"Some of the opinions voiced by some parties have led some stakeholders to consider a potential ban on oxo-biodegradable additives. This seems unjustified, unnecessary, and also counterproductive. For the foreseeable future, conventional plastics will continue to be used all over the world, in increasing amounts due to global development, despite the efforts of environmentalists and governments in some countries. Even if oxo-biodegradable technology was no longer available on the European market, large quantities of conventional plastics will continue to enter the ecosystem and will remain there as a problem for future generations. Therefore, a ban would be ineffective because it would have no perceivable impact on the problem."

"Perhaps the most important point is this: whatever the speed of degradation, it is faster than that of conventional plastics. The different opinions of various stakeholders concerning the speed of degradation, and the different findings of the limited research that has been carried out to date, are simply a matter of degree."

"A ban of any product would normally be justified only where there existed proof of significant harm. In the case of oxo-biodegradable plastics, the worst possible case (based on the views of the most sceptical stakeholders) could be that oxo-biodegradable plastics are little different from conventional plastics in terms of environmental impact. The best possible case is that they would be beneficial in relation to the micro-plastics issue. The point is that the range is neutral-to-good, not harmful. Therefore, a ban does not seem to be logical or justified."

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