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Everything falls apart: How solids degrade and release nanomaterials, composite fragments, and microplastics
Published
Author(s)
Wendel Wohlleben, Nathan Bossa, Denise Mitrano, Keana C. K. Scott
Abstract
To ensure the safe use of materials, one must assess the identity and quantity of exposure. Solid materials, such as plastics, metals, coatings and cements, degrade to some extent in their life cycle, and releases can occur during manufacturing, use and end-of-life. Releases (what is released, how does release happen, how much is released, etc.) depend on the composition and internal (nano)structures of the material as well as the applied stresses during the lifecycle. We consider, in some depth, releases from mechanical, weathering and thermal stresses and specifically address the use cases of fused-filament 3D printing, dermal contact, food contact and textile washing. Solid materials can release embedded nanomaterials, composite fragments, or micro- and nanoplastics, but can also release volatile organics, or ions and dissolved organics. The identity of the release is often a heterogenous mixture and requires adapted strategies for their sampling and analysis, with suitable quality control measures. Ideally the controls would use reference materials, which are not always available yet. The quantity of releases is typically described by time-dependent rates that are modulated by the nature and intensity of the applied stress, the chemical identity of the polymer or other solid matrix, and the chemical identity and compatibility of embedded ENM or other additives. Standardization of methods and the documentation of metadata, including all the above descriptors of the tested material, of the applied stresses, of the sampling and analytics, are identified as important needs to advance the field, and to generate robust, comparable assessments. In this regard, there are strong methodological synergies between the study of all solid materials, including the study of micro- and nanoplastics. As an outlook, we review the hazard of the released entities, and address the transfer of methods to related issues such as tire wear, advanced materials and advanced manufacturing, biodegradable polymers, and non-solid matrices. As they are poised to become more routine in industry via the lifecycle assessment in Safe-and-Sustainable-by-Design practices, release assessments will require careful study design with quality controls and standardized methods where these exist.
Wohlleben, W.
, Bossa, N.
, Mitrano, D.
and Scott, K.
(2024),
Everything falls apart: How solids degrade and release nanomaterials, composite fragments, and microplastics, NanoImpact, [online], https://doi.org/10.1016/j.impact.2024.100510, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=957111
(Accessed October 7, 2024)