Experimental approaches to data generation for REACH compliance of multi-walled carbon nanotubes: environmental fate

Abstract

Applying regulatory-accepted, standardised test guidelines to carbon-based nanomaterials is challenging. A primary difficulty is to analytically distinguish these nanomaterials from the high carbon background of the environment. Further challenges arise from the physicochemical characteristics of multi-walled carbon nanotubes (MWCNTs), which form entangled, highly cohesive bundles that agglomerate rapidly. As a result, many analytical methods are not suitable. This study evaluated the applicability of existing standardised analytical methods and explored potential alternatives. We focused on EU-REACH data requirements related to environmental fate, specifically nanomaterial dissolution, dispersion stability, and adsorption/desorption properties. Additionally, we assessed the feasibility of a sewage treatment plant (STP) simulation study according to OECD TG 303A, considering various analytical methods, including isotopic signatures. The findings of this study highlight challenges and novel analytical approaches in generating data for REACH registration purposes, and identify research needs.