S. Bernatchez, A. Afghan, D. Lai, P. Sayre, M. Hill
New Substances Assessment and Control Bureau, Canada
pp. 578 - 580
Keywords: nanomaterials, nanoparticles, toxicity screening framework
The framework proposed here was developed under the Canada-US Regulatory Cooperation Council (RCC) Nanotechnology Initiative and represents a concern-driven approach to focus human health concerns and additional testing requirements for nanoparticles based on their physical characteristics (i.e. particle shape, aspect ratio, particle/fibre size, solubility, composition and surface chemistry). It is intended as a paradigm for the human health risk assessment of particles under existing regulatory frameworks. Particle toxicology differs from molecular toxicology in that the particles’ physical characteristics are often the primary drivers of toxicity rather than their composition. Consequently, different paradigms are required in particle risk assessment. Particles come in various shapes, sizes, composition. A substance with a fixed composition can now be engineered into different shapes with varying physical characteristics. Although these different forms possess identical composition, the effects of changing the physical parameters may alter the substance’s behaviour in environmental and biological media, thereby influencing its toxicological properties. The magnitude and specificity of this influence are currently impossible to predict in absence of nanoparticle-specific test data. Using the approach outlined herein should lead to more focused toxicological testing and a more tailored risk assessment of new particulate substances, including nanoparticles.