In current political debates, for example in the context of negotiations on a future global plastics agreement, the increased recycling of plastics is seen as a key lever for greater sustainability. However, an article now published in the journal Cambridge Prisms: Plastics points out that existing recycling systems have fundamental weaknesses - especially with regard to the chemicals contained in plastics.
The article was written by an international team of authors led by Bethanie Carney Almroth, Eric Carmona, Nnaemeka Chukwuone, Tridibesh Dey, Daniel Slunge, Thomas Backhaus and Therese Karlsson. The researchers make it clear that plastics contain a wide variety of chemical substances. These include monomers, polymers, processing aids, fillers, antioxidants, plasticizers, pigments, biocides and stabilizers.
Lack of transparency about chemical composition
According to the authors, the type and quantity of these chemicals vary greatly between different plastic products. At the same time, there have so far been few requirements for transparency, reporting and traceability. In addition, plastics are often contaminated with reaction by-products and non-intentionally added substances (NIAS).
As the chemical composition of plastic waste is unknown in many cases and many of the substances used are considered potentially hazardous, recycling has its limits. Recycling companies are often unable to reliably sort out materials with problematic ingredients. This makes safe recycling more difficult and can result in risks to the environment and health.
Political strategies for safe plastics recycling
To address these challenges, the authors propose several political approaches. These include significantly improved reporting, transparency and traceability of chemicals across the entire life cycle of plastics. They also advocate chemical simplification and group-based regulatory approaches for hazardous substances.
Other recommended measures include the expansion of chemical monitoring, systematic testing and quality control as well as economic incentives based on the waste hierarchy. In addition, the authors emphasize the importance of a just transition that also protects the people affected along the entire plastics life cycle - including informal waste collectors.
Importance for industry and regulation
The article makes it clear that expanding plastic recycling alone is not enough to minimize environmental and health risks. In the authors' view, a safe circular economy is only realistic if the chemical basis of plastic products is given greater consideration and addressed by regulation. This applies not only to the waste and recycling industry, but also to manufacturers, processors and political decision-makers alike.