Enabling a circular economy for chemicals in plastics
Enabling a circular economy for plastics in Europe and beyond is an ambitious goal. To reach a fully closed loop, numerous challenges and knowledge gaps need to be overcome. This review provides a list of more than 6000 chemicals reported to be found in plastics and an overview of the challenges and gaps in assessing their impacts on the environment and human health along the life cycle of plastic products. We further identified 1518 plastic-related chemicals of concern, which should be prioritized for substitution by safer alternatives. At last, we propose five policy recommendations, including the need of a global and overarching regulatory framework for plastics and related chemicals, in support of a circular economy for plastics and of target 12.4 of the UN Sustainable Development Goals.
State of knowledge of chemicals in plastics
Overview of chemical additives
The production of chemicals for plastics is continuously increasing in terms of both quantity and diversity, with several thousand chemicals used across many material applications. Estimating global additives production is not an easy task, because these data are usually not publicly available. However, with a global plastic production of 368 Mt in 2019, and assuming 1–10% additives mass fraction for nonfibre plastics, the total amount of additives used in 2019 might be around 20 (3.6–36.8) Mt. If plastic production follows current increasing trends, it is estimated that we will have produced 2000 Mt of additives by the end of 2050. Plasticizers are the most used additives and together with flame retardants cover almost 50% of globally applied additives. Owing to their wide-ranging application and high-production volumes, these two types of additives have been receiving special attention (e.g. Commission Regulation (EU) 2018/2005).
Additives are applied during the production process at different concentrations based on the specific function that they need to fulfil. It provides an overview of functions, typical material application, chemical classes, and application ranges. For example, plasticizer application ranges vary across materials, and can reach up to 60–70% of the plastic mass in soft PVC resin products. Other additives are usually applied at much lower concentrations, such as 0.7–25% for flame retardants or 0.05–5% for stabilizers and antioxidants. The concentration of unintentional residues is typically