112 Framework development for grouping polymers based on their toxicology

Abstract Polymers are essential across various industries, used in everything from medical devices and packaging to automotive components and electronics, highlighting their versatility in modern life. However, their diverse chemical structures, complex degradation processes, limited toxicity data, various manufacturing process and interactions with other substances complicate hazard assessments. Given the impracticality of individual animal testing for each polymer, there is a critical need to streamline and standardize toxicity assessments to better manage the environmental and health risks associated with their extensive use and ongoing innovation. Grouping is an approach that streamlines hazard assessment by providing evidence of similarity between substances so that animal hazard data can be read-across from one group member to another. This would allow assessment of the vast number of polymers to address environmental and human health concerns while promoting the 3Rs (Replacement, Reduction, and Refinement of animal studies) for hazard studies. It introduces a novel strategy integrating the existing grouping framework (from the EU project GRACIOUS) by replacing nano-specific elements with polymer-specific considerations. In the developed polymer grouping hypothesis, which includes consideration of the purpose of grouping and the lifecycle of polymers, and answers the fundamental questions of what they are, where they go, and what they do. Two case studies, polyacrylic acid (PAA) and polyethylene glycol (PEG) through inhalation exposure are included. These case studies demonstrate the practical application of the framework and highlights future directions for research and implementation. This project presents a significant advancement in polymer risk assessment, emphasizing the need for efficient, cost-effective, and comprehensive evaluation methods.