A recent report that appeared under the title ‘Bioplastics Are Trash: the unforeseen environmental consequences of PLA from production to disposal’ and that was compiled by the North American branch of the international consultancy firm Eunomia, purported to explore the sustainability of one of the more commonly used bio-based plastics today: PLA.
‘Plastic pollution is widely recognised as a threat to human and planetary health’, the report states. This recognition is ‘creating a market for alternative materials such as bio-plastics which are made to look, feel, and perform like conventional plastics, but are derived from non-fossil-based feedstock’, and this report aims to assess the ‘extent to which PLA is a sustainable alternative to conventional, fossil-based single-use plastics’.
Commissioned by the Plastic Pollution Council, the report’s findings make interesting reading. Its overall conclusions, in particular, give pause for thought.
Sustainable Plastics spoke with Leah Ford, Global Marketing & Communications director at NatureWorks, one of the PLA producers mentioned in the report, about that company’s perspective on its contents.
The tenor of the report slanted towards the negative, she noted. Hence: “These types of reports are frustrating, because we're really trying to move this industry into a more diverse direction,” said Ms Ford.
Among the key findings were the concerns about land use for materials production. It is a concern that has been extensively researched and discussed, among others, by European Bioplastics, the trade association for bioplastics in Europe. PLA is today mostly made from carbohydrate-rich food crops, such as corn or sugar cane; also known as first generation feedstock.
“In the early years, for NatureWorks, using these crops was a big question and a big concern,” said Ford. “However, work published by various organisations, such as EuBP, nova-Institute and the Institute for Bioplastics and Biocomposites has demonstrated that currently, some 96 percent of the global agricultural area is used to grow food and feed or used as pastures. The area needed to grow biomass for material use accounts for approximately 2 percent. Within this share, bioplastics account for just 0.03 percent – a mere sliver.”
Moreover, she pointed to the fact that in the US, most of the corn that is grown is not used for food. It is industrial corn of which the proteins go to livestock feed, the oil is used as corn oil for a variety of food ingredients and the starches for everything from making paper adhesives, batteries to high fructose corn syrup to PLA. “Every acre is highly productive for downstream markets. It is one of the main benefits to corn,” she emphasised.
Moreover, she said, the report goes on to state that ‘context-specific LCAs are required to determine PLA’s impact relative to fossil-based plastics’ – without mentioning that this data is already available. Both NatureWorks and TotalEnergies Corbion, another PLA manufacturer, have compiled extensive eco-profiles that, said Ford, ‘are some of the most specific ones that exist’. There are no specific LCAs or eco profiles like that for other plastics, Ford pointed out.
“And both come out with similar carbon footprints, which is really interesting. Given that they're very different feedstocks in very different countries, we still came to roughly the same carbon footprint.”
The Eunomia report goes on to claim that ‘PLA cannot be easily recycled along with conventional plastics, which can lead to contamination given PLA can be confused with conventional plastics by consumers when sorting their recycling’. What it fails to mention is that PLA is readily sortable using industrial standard near infrared sorting technologies. Purities of 97% have been obtained – a percentage higher than most traditional plastics. Furthermore, studies have shown that PLA does not contaminate the traditional plastic recycle stream any more than other traditional plastics; in fact, adding 10% PLA into polyolefin recycling streams has the same impact on the material properties as adding 10% PET or PS to these streams. ‘PLA bioplastics can be mechanically and chemically recycled and there are no technical barriers to doing so’ states a whitepaper compiled by TotalEnergies Corbion.
“Recycling can really work beautifully,” agreed Ford. “ We've done it in multiple closed loop venues – music festivals and the like - in both the US and in Europe, where we've collected all the cups and sent them either to mechanical recycling or even chemical recycling to recapture the lactic acid. Both are very doable in a closed loop setting.”
She also noted that the current debate about the recycling versus composting of PLA was not about the ‘best’ end of life option, but about the most sustainable option in any specific case.
“This [report] felt like it was trying to take a little position on shaping that debate. But we can't be in this market if we aren't trying to hit really high sustainability goals and be able to answer questions like the ones raised here. Because brands won't take that risk. They too have a responsibility and must report on their material choices. We've learned a lot in the time since we started manufacturing this material, and we know the sustainability credentials we need to get.”
It would therefore seem that, while the ‘Bioplastics are trash’ report does explore the sustainability of PLA in some detail, it fails to tell the whole story. The reason can perhaps be found in the final paragraph of the report’s conclusion.
‘Current solutions to plastic and bioplastic waste focus on recovery and recycling. However, the principles of the waste hierarchy should lead to the prioritisation of reduce and reuse’, the authors write.
There is no doubt that reduce and reuse play a major role in plastic waste management. But that alone will not be enough to solve the plastic waste crisis currently confronting the planet. In that light, it is worthwhile evaluating all the options – openly and evenhandedly.
Different materials have different end-of-life disposal options and these can even vary per application. Just as reduce and reuse, recycling, recovery and even compostability may all be considered key components in the efforts to tackle plastic waste.
Bioplastics do end up as trash, as do so many other kinds of plastic. The point is, of course, what is the most sustainable way to handle these materials at the end of life?
According to this report, the sustainability of PLA ‘is conditional on the development of appropriate policies and regulations to minimise or eliminate unintended and negative production consequences, alongside comprehensive waste management strategies and large-scale infrastructure investments’.
Exactly. If all plastics could be held to this standard, we would be well on our way to solving the plastic pollution problem.