European Bioplastics trades blows with University of Gothenburg over “misleading” PLA toxicity study

11 Oct 2023 --- European Bioplastics has accused the University of Gothenburg, Sweden, of “damaging the reputation of the bioplastics sector” after publishing a press release on an investigation into the toxicity of polylactic acids (PLA) in paper cups, which the industry association deems “misleading” and “erroneous.”

The press release detailed the findings from a study titled “Single-use takeaway cups of paper are as toxic to aquatic midge larvae as plastic cups,” published in Environmental Pollution.

The study examined the impact of discarded paper cups and plastic cups in a marine environment and found both to have a toxic effect on larvae. PLA, a bioplastic typically composed of corn starch or sugarcane, is used as a grease repellent for paper applications to make renewable materials (like paper) suitable for F&B packaging. 

The university’s press release brands the replacement of plastic cups with paper as “problematic.” It states that “PLA is often regarded as biodegradable, meaning that it can break down faster than oil-based plastics under the right conditions, but the researchers’ study shows that it can still be toxic.”

European Bioplastics has retorted, stating that: “It is essential to clarify that the study’s findings pertain to the toxicity of single-use cups, which are composed of various materials, including paper, adhesives, inks and PLA.”

“The research does not conclusively attribute toxicity to PLA specifically. We must emphasize that this misrepresentation has contributed to significant confusion regarding the correlation between biodegradability and toxicity, as well as the unverified assertion that all single-use items are inherently toxic due to the presence of PLA.”

Correlating toxicity 
Dr. Bethanie Carney Almroth, professor of ecotoxicology and environmental science at the university’s Department of Biological and Environmental Sciences, who led the study, tells us that while press releases do not necessarily reflect a study’s findings, she agrees with the university’s portrayal of the research. Study lead Dr. Almroth encourages further research to help the industry understand how to eliminate harmful substances in packaging.

“A researcher will report their current findings but may very well comment on the research field as a whole to put the current study into context — this is not to mislead the reader, rather the opposite since the researcher refers to other earlier studies made in the matter,” she says. 

Almroth also points to several other studies in the reference section of her paper regarding the toxicity of PLA.

“In my role as a researcher, it is not my task to evaluate their [the bioplastics sector] reputation. It is, however, my role to not only communicate but also to contextualize scientific research results.”

European Bioplastics says it believes the development of robust methodologies for assessing environmental hazards associated with various littered materials is of “utmost importance” and that the article represents “a significant step” to creating a comprehensive framework for evaluation and policy direction. 

However, the association also says accurate scientific communication must be shared with the general public and European stakeholders. “Sadly, this press release is contributing to disseminating inaccurate information and bringing confusion to a sector that is already facing many misconceptions and false claims,” it asserts. 

In a similar dispute, European Bioplastics recently challenged a “first-of-its-kind” study, which found that synthetic textiles, including “compostable” plastics like PLA, do not degrade after more than a year in the ocean. The bioplastics industry dismissed the findings as irrelevant, pointing out that the fashion industry does not use PLA because it is “compostable” but because it is bio-based and avoids fossil-based resources.

Further research 
While the university’s press team decided that it would not issue a supplementary press release emphasizing that the study does not draw a direct link between PLA and toxicity, Almroth says further research can be done to aid the packaging industry in identifying and eliminating harmful substances from its products. The University of Gothenburg researchers warn that paper-based cups can be toxic, but European Bioplastics highlights that the study does not specifically attribute toxicity to PLA.

“While the burden to produce non-toxic bio-based plastics should lie with producers and R&D experts, scientists such as myself can test the validity of claims of safety and sustainability, and can do so using real-life products in both standardized testing paradigms, ecologically relevant scenarios, or new fit for purpose methodologies.”

“We cannot simply replace one product or material with another without ensuring that we are avoiding regrettable substitutions. Solutions need to be evaluated from a systems perspective so that implications are broadly understood and we can find the best way forward toward safe and sustainable production and use of plastics,” she says. 

A provision of the ongoing UN negotiations for a legally binding global plastic treaty is that chemicals and polymers of concern should be identified using rigorous scientific standards and banned or restricted accordingly. 

“As evidence shows that PLA does not always degrade completely in different environments, clear and concise standards for degradation of biodegradable plastics in different environments (for example, industrial composters, soil and marine systems) are also necessary,” asserts Almroth. 

“Safety and sustainability criteria should apply to all plastics.”

By Louis Gore-Langton