On November 8, 2023, Earth Action (EA) released a report assessing the leakage of plastic additives into the environment. The study introduces a mathematical approach to modeling and quantifying the total volume of plastic additives that leak into both oceans and terrestrial ecosystems as a result of mismanaged plastic waste. In addition, the authors investigated the health and environmental consequences of these plastic additives in the environment (FPF reported).
The lack of comprehensive studies on the scale of plastic additive leakage hinders the development of effective risk assessment procedures, regulatory mechanisms, and recycling processes, the authors emphasized. By estimating the total annual leakage of additives from plastic products into the ocean and terrestrial environments, the study aims to contribute to an effective risk assessment and the development of strategies to mitigate further pollution from plastic additives.
The authors primarily quantify the release of plastic additives into the environment during the end-of-life phase and, in the case of textiles and tires, during use in the form of microplastics. The research methodology involves mathematical modeling, calculating plastic waste generation, estimating leakage, and assessing the corresponding volume of leaked additives. Data from scientific literature, technical reports, and databases were used to study the quantity, types, and utilization of additives, as well as plastic waste production and management.
According to the study, the majority of additives, over 98%, are found in the four commonly used polymers polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), and polystyrene (PS). Approximately 971,000 tons of additives were found to enter marine ecosystems annually, with an additional 5,650,000 tons ending up in terrestrial areas, based on the total amount of plastic production for the year 2021. 1,238,000 tons (18.7%) of the total leakage was attributed to plastic packaging. 208,000 tons (16.8%) of which comes from mismanaged PET bottles. The authors indicated that inadequate waste collection systems, littering, and improper disposal of plastic products are responsible for that leakage (FPF reported).
The consequences of plastic additives in marine environments named in the report include negative impacts on aquatic life, ecosystem health, and human well-being through bioaccumulation and biomagnification. The report projects a potential 50% increase in annual leakage of plastic additives into oceans and waterways by 2040 unless there are significant changes in plastic production rates, chemical composition, or improvements in waste management practices.
In their conclusion, the authors present eight principles for a way forward, including:
- Selecting polymers that are easily reusable, recyclable, or biodegradable;
- Reducing or substituting problematic chemical compounds;
- Distinguishing between essential and non-essential plastic products;
- And expanding transparency for the chemical composition of plastic items.
EA emphasized that “[…] a multifaceted approach is necessary to confront the complexities associated with plastic additives. This includes ongoing research and scientific investigation, regulatory interventions, and fundamental shifts in the use and management of certain additives.”
In a report published on November 2, 2023, Arturo Castillo Castillo and co-authors from the Institute for Molecular Science and Engineering, Imperial College London, also focused on plastic additives reviewing the current knowledge base and proposing ways forward towards non-toxic materials.
Framing the problem, the authors pointed out that known toxic additives are used in plastics of which the consumer is unaware making informed decisions impossible. Furthermore, they highlighted that data is missing on the toxicity of single additives but still, they are used until proven harmful, and if replaced they are often substituted by equally toxic alternatives (i.e., regrettable substitutions). As a further knowledge gap, they described the lack of data on the interaction of additives, as occurring in the real world. Castillo Castillo and co-authors divided “what we are currently doing wrong” into wrong definitions and reactive approaches, wrong testing, and regrettable substitutions.
Subsequently, the topic briefing provides recommendations on how to make additives safer and how policymakers and other stakeholders can contribute to it. Here, the authors discussed that low-dose effects need to be considered in toxicity testing (FPF reported) as well as mixture effects. For the latter, they propose to include biomonitoring data to account for the complexity occurring in real-world exposures. To avoid regrettable substitutions and speed up regulatory action, the scientists confirm the opinion of the European Chemicals Agency (ECHA) and others to regulate chemicals as a group (FPF reported). Interestingly, instead of proposing regulatory obligations, the authors ask consumers, governments, and producers “to demand the use of non-toxic chemicals” in plastics as well as “full supply chain transparency.” Coming from a molecular science and engineering background, Castillo Castillo et al. further emphasized actions for their discipline including the development of new non-toxic alternatives to existing additives, methods to better monitor additives’ presence, models to assess real-world chemical interactions, and new processes to reduce additive leakage into the environment.
A measure to reduce exposure to toxic chemicals not addressed by the authors is chemical simplification, i.e., the reduction of chemicals used in plastic production (FPF reported and here).
For the launch of their briefing paper, the Institute for Molecular Science and Engineering organized an in-person and online event where the paper was presented and questions addressed in a panel discussion.
Various stakeholders will have the opportunity to discuss a way forward with plastic additives at the UN Intergovernmental Negotiating Committee (INC) convening for the third time on November 13 – 19 in Nairobi. The intent is to draft a global plastics treaty by the end of 2024. The Zero Draft text published by the INC’s Secretariat in September is designed to guide the discussions ahead (FPF reported).
References
Earth Action (November 8, 2023) “Adding it up: A global assessment of plastic additives leakage.”
Castillo Castillo, A. (November 2, 2023) “Addressing plastic additives.” DOI: 10.25561/105699
