Streszczenie: Komisja Europejska opublikowała raport, wykonany przez niezależną firmę konsultingową, dotyczący wpływu materiałów „oxo-degradowalnych” na środowisko, z którego wynika, że wyroby „oxo-degradowalne” nie są przydatne do żadnych form kompostowania i wpływają negatywnie na proces recyklingu. Ponadto, KE bierze pod uwagę możliwość zakazu stosowania tego typu wyrobów na terenie Unii Europejskiej.
Abstract: The European Commission has published a report prepared by an independent consulting company on the impact of „oxo-degradable” plastic on the environment. It clearly shows that „oxo-degradable” products are not compostable under any conditions and have negatively influence on the recycling process. In addition, The European Commission takes into consideration the possibility of prohibition of such products in the EU.
1. Introduction
Oxo-degradable or oxo-biodegradable plastics are conventional plastics, such as High Density Polyethylene (HDPE), commonly used in carrier bags, which also include additives which are designed to promote the oxidation of the material to the point where it embrittles and fragments. This may then be followed by biodegradation by bacteria and fungi at varying rates depending upon the environment. It has been debated for some time whether or not these additives perform in the way in which their manufacturers claim they will, whether they cause harm to the environment, and whether they effectively make plastics recycling more problematic. In November 2014, Members of the European Parliament proposed an outright ban on „oxo-degradable” plastics within the EU. Although this measure was blocked, an amendment to the Packaging and Packaging Waste Directive, adopted in May 2015, commits the Commission to examine the impact of the use of oxo-degradable plastic on the environment.
„By 27 May 2017, the Commission shall present a report to the European Parliament and to the Council, examining the impact of the use of oxo-degradable plastic carrier bags on the environment and present a legislative proposal, if appropriate.” [1].
This study has been undertaken in response to that request and compiles the requisite information regarding environmental impacts of this material, to the extent that such information is available, in order to form an opinion on any appropriate actions to be taken. The report presented here draws on the available scientific literature in order to investigate the claims from the industry with regard to biodegradation in different environments, and compatibility with current recycling processes. Input from key stakeholders—including the industry itself – has been used during the review to understand the impacts of the use of these materials.
Throughout this study, the material is referred to as Pro-oxidant Additive Containing (PAC) Plastic as a means of describing the material’s physical make up, and without implying any presumption as to how it will behave in different environments.
2. Issues Related to Biodegradation
The following are the key findings of this study regarding whether or not PAC plastic biodegrades in different environments.
2.1. Composting and Aerobic Digestion
The evidence suggests that PAC plastic is not suitable for any form of composting or Anaerobic Digestion process and will not meet current standards for packaging recoverable through composting in the EU (EN 13432). PAC plastics are designed to degrade in much slower timeframes than are required for industrial composting. There is, therefore, a risk that fragmented plastics could be applied to land. In most countries that have compost standards in place, the output is strictly controlled, and the presence of plastic fragments would invariably lead to a failure to meet these standards. It should be recognized that the majority of PAC plastics manufacturers do not claim that their products are suitable for composting.
2.2. Open Environment
The review of evidence undertaken for this report suggests that whilst PAC plastic can biodegrade under certain circumstances, there is still doubt as to whether they do so fully or within reasonable time periods in practice (and acknowledging the impracticality of defining what a ‘reasonable” time period might be). One finding that is clear is that PAC plastic is prohibited from biodegradation if it is not first exposed to UV radiation (and, to a certain extent, heat). This breaks down the anti-oxidants and accelerates the oxidation process that is triggered by the pro-oxidant additives. This first abiotic stage of degradation prepares the PAC plastic for biodegradation by reducing the molecular weight of areas on the plastic surface to the point where it can be consumed by biological organisms, kick-starting the biotic degradation phase. If the circumstances for this to
take place are absent (e. g. if UV exposure is only fleeting), biodegradation will either not take place (it will behave as a conventional plastic) or will be slowed significantly. This is the same for all environments.
Extrapolations from a laboratory study on a particular LDPE film engineered with a short service life suggest that almost complete degradation in soil can be achieved within two years (following perhaps one year of abiotic degradation while the material is in use).
With the results of the laboratory study showing over 91% conversion to CO2, the author contends that the „risk of plastic fragments remaining in soil indefinitely is very low.” Nowhere is such a claim for complete bio-assimilation proven in practice though.
Other studies have shown significantly reduced biodegradation, suggesting that anything less than ideal conditions will, at very least, extend the timeframe for biodegradation. Furthermore, different products should be expected to behave differently. One major issue for PAC plastic is the trade-off between the intended service life period, and the period that may be needed for degradation in an open environment. Although it can be believed that biodegradation can be facilitated by careful engineering of the chemical package in PAC plastic, evidence is not available to definitively conclude that this will happen in real world situations with PAC plastic products being placed on the market.
2.3. Landfill
The degradation that occurs in landfill is primarily confined to the initial aerobic stage in the higher levels of the landfill. In the absence of oxygen (under anaerobic conditions of landfill operations), the PAC plastic is thought not to biodegrade. This makes PAC plastic marginally worse than conventional plastic from a GHG point of view as it may lead to emissions of fossil CO2 during the period where biodegradation takes place (if it does in practice to any meaningful degree).
2.4. Marine Environment
There is currently insufficient evidence to provide assurance that PAC plastic will biodegrade in the marine environment.
Very few tests have been conducted, and there are currently no standards that can be met which will allow a certification.
Biodegradation is expected to be much slower in water compared to land based open environments. Evidence is not available to properly understand the fate of PAC plastic in marine environments, and thus there remains a risk that plastic fragments may remain either indefinitely, or for long enough to cause significant environmental damage.
3. Issues Related to Littering
Directly related to the issues of biodegradation are those of littering and how the PAC plastic will behave if it is littered, and thus, what impacts might be expected.
3.1. Toxic Effects
The potential toxic effects on soils of any residual additives have been identified as a concern by some commentators. Whilst it has not been conclusively proven that there are no negative effects, it does appear that the PAC plastics industry can create products that have minimal toxic impact on flora and fauna. This does not mean that all products on the market avoid negative toxic effects, as there is no regulatory control currently exercised in this regard. It is at least encouraging that almost all existing test standards for PAC plastic specify some form of toxicity test using established methods (such as germination and earthworm survival tests). However, problems remain that (a) accreditation is not mandatory for products on the EU market, (b) some of the standards do not have pass/fail criteria for the toxicological test results, and (c) there remains uncertainty surrounding real world toxicological impacts.
3.2. Increase in Littering
There is a suggestion, on the basis of the evidence which is available, that indicates a greater tendency for littering to occur if the user believes that the substance is ‘biodegradable”. Although there is no noticeable physical difference between PAC | plastic (until it starts to fragment) and conventional plastic, specific markings can be placed on products at the point of manufacture to differentiate a PAC plastic product. It is also possible-indeed it seems quite likely-that there would be some form of marketing extolling the claimed benefits of PAC plastic products in this regard. Consequently, it may be that littering of PAC products is more likely because of claims regarding their biodegradability. Nevertheless, rather than speculation, objective behavioral research is required to move this topic forward in a constructive manner.
3.3. Marine Litter
As indicated above, there is no conclusive proof of PAC plastic biodegradation in the marine environment. It is the least aggressive of all the environments investigated in this report, but arguably, it is also the environment where the most damage could be done, and with the least chance of subsequently recovering the plastic.
With PAC plastic being more likely to fragment than conventional plastic, to the extent that this occurs, it is less likely to be recovered during litter clean-up exercises, and will also likely be more easily mobilized. These factors can be reasoned to increase the chance of being transported into the marine environment. However, should full biodegradation on land occur, this would reduce the quantity that may otherwise transfer to the marine environment. It is not possible to conclude whether PAC plastic would increase or decrease absolute quantities of plastic in marine environments.
Nonetheless, it seems likely that the fragmentation behavior of PAC plastics will exacerbate issues related to microplastics.
Working under the assumption that PAC plastic in marine environments will be more fragmented, the effect may be to reduce the impacts on wildlife in some respects (such as entanglement), but to increase the impacts in others (such as physical ingestion of microplastics). The PAC plastic is more likely to fragment quicker so the impacts associated with microplastics are concentrated within a shorter period of time – this could ultimately be worse than spreading out the impacts over a longer period of time due to an increase in the proportion of individuals, species and habitats affected, as well as the burden of impacts for an individual of a species. Although we are not able to provide conclusive judgement on marine issues, concerns remain that PAC plastics do not eliminate impacts, and also that impacts may be increased in certain important impact categories.
4. Issues Related to Recycling
On issues relating to recycling of PAC plastics, the following key conclusions are drawn.
4.1. Identifying PAC Plastic
The evidence available does not support the suggestion that PAC plastic can be identified and sorted separately by reprocessors with the technology that is currently available.
Furthermore, manual sorting would be time-consuming and is unlikely to be economically viable. In the absence of market controls within any individual country, recycling of PAC plastic must, therefore, be considered in the context of a mixture with conventional plastic.
4.2. Quality Issues
There are significant concerns within the recycling industry that PAC plastic negatively affects the quality of recycled plastics. Evidence suggests that the impacts of prodegradant additives on recyclates can under certain circumstances be avoided with the inclusion of stabilizers. The appropriate quantity and chemistry of stabilizer would depend on the concentration and nature of the prodegradants in the feedstock. This presents significant issues, as the concentration of PAC plastic in recyclate in real world situations where the market is not controlled is unknown, and therefore it is difficult to know the correct dosing. Furthermore, evidence suggests that oxidised PAC plastic can significantly impair the physical qualities and service life of the recycled product. The fact that it is impossible to fully control the level of aging experienced by PAC plastics during the product use phase, prior to products becoming waste and entering recycling processes, presents a major issue.
Recyclate made from mixtures containing unknown PAC plastic should not be used for long-life products, due to the lack of evidence surrounding the long-term impact in secondary products. The existence of PAC plastic and the global nature of secondary materials markets does, therefore, present risks of using recovered plastic in such applications. The uncertainty of whether recyclate may – or may not – contain PAC plastic, and the degree of oxidation likely to have occurred prior to recovery, therefore results in limits on the end-use for the recyclate.
For shorter-life products, it may be possible to create a recyclate, which has no reduced properties over the short-term life of a particular product. However, most of the evidence suggests that the concentration of PAC plastic in the feedstock resin may be important – though evidence is not sufficient to suggest what limits should be followed.
It must also not be ignored that any oxidation and degradation of PAC plastic that occurs prior to recycling will impair the recyclate.
4.3. Marketability of Recyclates
Opinions and anecdotal evidence provided by the plastics recycling industry indicate there is significant risk associated with PAC plastic due to the way in which it is perceived by reprocessors. The inclusion of PAC plastic has a negative effect on the marketability of plastic films sent for recycling. The industry is keen to eliminate PAC so as to minimize any effect on prices related to the quality and marketability of secondary materials.
5. Summary
This report is split into 13 distinct hypotheses, each of which reflect either a claim from the PAC plastics industry or a commonly held belief about the material. The hypotheses are addressed, in turn, and the evidence is gathered and analyzed to ascertain whether the hypotheses can be supported or refuted. The summary of this exercise is shown in Table 1 (with a green to red color coding indicating whether each hypothesis is upheld or not).
6. Recommendations
The debate around the biodegradability of PAC plastic is not finalized, but should move forward from the assertion that PAC plastics merely fragment, towards confirming whether the timeframes observed for total biodegradation are acceptable from an environmental point of view and whether this is likely to take place in natural environments. The variety of formulations – most of which are proprietary and confidential – and the lack of regulation of them means that there are no guarantees that all PAC plastic will perform appropriately in the markets in which they are sold, and in environments they may end up.
No suitable certifications are available currently that allow a PAC plastic supplier to claim that biodegradation will happen in a certain environment to a particular set of requirements.
Certifications from France and the UAE are not without shortcomings, and neither should be adopted as best practice by the EU. For PAC plastic to remain on the market, work to develop a (set of) European standard (s) should be a matter of priority.
One of the biggest issues to be confronted by both policy makers and the PAC plastics industry when deciding on limits and controls is that there are no unified standards. We have observed throughout this research that the PAC plastics industry consists of different manufacturers and stakeholders, each of which claims to have developed the definitive method for assessing biodegradability: indeed, new methods appear to be surfacing all the time. This makes it less than straightforward to garner a rational body of evidence on the matter – as results from differing tests are incomparable – and to define a suitable approach through which one can be sure that the PAC plastics industry, as a whole, produces products that are not environmentally harmful.
In the meantime the PAC plastics industry should be prevented from selling their products into markets that have been conclusively proved to be unsuitable – primarily composting and AD markets. There is also no clear evidence to support the contention that PAC plastic is a solution to the problem of plastic in the marine environment: it is suggested that no form of communication should be permitted that uses this as selling point, especially for single use items (the sort of products which PAC plastic is primarily aimed at).
It would go some way to alleviate fears of toxic effects if all PAC plastic products in the market were required to pass toxicity tests. As the PAC plastics manufacturers specifically state that their products are designed to help deal with the effects of littering it is incumbent upon them to demonstrate that each product they sell does not have a negative toxic effect on the environment that it may be littered into. Such tests should be included as part of any European standard.
The issue of littering behavior is something not confined to PAC plastic but applicable to all products that claim to be biodegradable or compostable – terms which are often synonymous in the mind of the consumer. California recognized this issue, and in 2011, regulated the use of these terms to help consumers make informed decisions without “greenwash”, and to target littering [2]. Specifically: „Environmental marketing claims, whether explicit or implied, must be substantiated by competent and reliable scientific evidence and meet specified standards to prevent misleading consumers about the environmental impact of degradable plastic products, including bags, food service ware, and packaging.”
This has resulted in court action on multiple occasions. The legislation also encourages manufacturers to work towards the production of appropriate standards that allow sound scientific tests to be performed to support any claim. Similar standardized regulation and alignment of nomenclature would also be beneficial to the EU and create a level playing field for manufacturers of products that are genuinely biodegradable in the relevant environments. It would also incentivize the PAC plastics industry towards aligning their efforts towards creating effective standards.
Sources
[1] Directive (EU) 2015/720 amending DIRECTIVE 94/62/EC on packaging and packaging waste.
[2] California Senate Bill No. 567 http://www.leginfo.ca.gov/pub/11-12/bill/sen/sb_05510600/sb_567_bill_20111008_chaptered.pdf.
Opracowano na podstawie raportu The Impact of the Use of "Oxo-degradable"
Plastic on the Environment For the European Commission DG Environment.
Project conducted under Framework Contract No ENV.A.2/FRA/2015/0008
Alfa-Print Sp. z o.o.
ul. Świętokrzyska 14A
00-050 Warszawa
