CEE Seminar – Assessing Releases from Solid Materials: From Stress to Exposure

Regulatory frameworks for chemicals, materials, and advanced products increasingly require quantitative exposure data as a core component of safety dossiers. For solid materials, however, exposure assessment remains challenging because releases are not static properties but emerge dynamically over a material’s life cycle, driven by mechanical, environmental, thermal, and use-related stresses. Without robust methods to identify what is released, how much, and under which conditions, exposure assessments risk being either overly conservative or fundamentally incomplete.
This seminar addresses how solid materials-including plastics, nanocomposites, and other internally structured materials-degrade and release substances during use and end-of-life, and how these releases can be used for regulatory decision-making and Safe-by-Design strategies. Drawing on recent advances in release science, I show that solids do not simply emit pristine additives or particles, but rather complex, heterogeneous mixtures including dissolved species, composite fragments, micro- and nanoplastics, and transformed nanomaterials. The identity and rate of release depend strongly on material composition, internal structure, and the type and intensity of applied stresses.
Building on a three-step release assessment framework-representative aging, controlled sampling, and multi-modal characterization-the seminar highlights how laboratory simulations can generate exposure-relevant data that are both mechanistically meaningful and regulatorily usable, supporting Safe-and-Sustainable-by-Design strategies. Examples spanning mechanical wear, weathering, and dermal contact of plastics, paints, and cement illustrate how release rates can vary by orders of magnitude, and why standardized metadata, reference materials, and harmonized methods are essential for comparability. Finally, emphasis is placed on the strong methodological synergies between nanomaterials research and the emerging challenges of micro- and nanoplastics, positioning release testing as a central tool for future environmental and human exposure assessments.