The United Nations is currently developing an international, legally binding instrument against plastic pollution. But scientists are concerned that this is ignoring the more than 10,000 different chemicals found in plastics. This would mean that the recycling measures that have been decided would be inefficient and the plastic contract would have little effect. The researchers therefore call for this aspect to be given sufficient attention.
Plastics are cheap and versatile, making them ubiquitous in our modern lives. But just as ubiquitous is the plastic waste that remains, polluting landscapes and seas and decomposing into dangerous microplastics. In March 2022, the United Nations Environment Assembly therefore decided to conclude a global plastics agreement by 2024 that is intended to minimize littering throughout the life cycle of plastics.
Diverse ingredients make recycling inefficient
But some scientists fear that the global community will not take full advantage of this unique opportunity. For example, Zhanyun Wang from the Federal Materials Testing and Research Institute in Switzerland and Antonia Praetorius from the University of Amsterdam are concerned that the highly diverse chemical composition of plastics may not receive enough attention in the negotiations. Because there can currently be more than 10,000 different chemicals in plastics, which has a negative effect on their recycling, as Wang and Praetorius explain.
“The enormous variety of chemicals in different plastic products makes the different waste streams incompatible. This incompatibility can significantly affect the quality of recycled products, leading to 'downcycling' and toxic waste that requires additional safety measures,” Wang said. This toxic waste poses a threat to the environment and health. The annoying thing about it: According to the two scientists, this enormous chemical variety is not even necessary and is only due to a lack of coordination between the manufacturers. Accordingly, plastics from different manufacturers often have different chemical compositions, although they serve the same purpose.
Global standards demanded
That has to change, say the researchers. The upcoming negotiations on the plastic contract are a unique opportunity to enforce such changes internationally. According to the scientists, an agreement that does not take into account the problem of ingredients would hardly be effective. Wang and Praetorius therefore recommend that the negotiators limit the diversity of ingredients globally. This is intended to make the chemicals that are in the products of different manufacturers transparent, standardized and kept as simple as possible.
The United Nations should also create incentives for plastics manufacturers to actually respond to the new handling. One possibility would be that "unnecessarily" various recipes lead to tax disadvantages. Wang and Praetorius see their demands as the necessary cornerstones for an effective circular economy worldwide, in which efficient recycling can take place. They hope that they will be included in the forthcoming negotiations.
Source: Federal Materials Testing and Research Institute; Specialist article: Environmental Science & Technology Letters, doi: 10.1021/acs.estlett.2c00763