Authors: C.M. Long
Affilation: Gradient Corporation, United States
Pages: 134 - 137
Keywords: carbon nanotubes, risk assessment, product lifecycle, nanocomposite
Although the Project on Emerging Nanotechnologies estimates that there are already over 500 nanotechnology-based consumer products on the market, few published data are available to support thorough nanomaterial safety assessments. To address questions of product safety in this time of uncertain information, we have developed a risk assessment framework that can provide a tool for qualitatively assessing the exposure potential of commercial nanomaterials. Since the health risk posed by a nanomaterial is a function of both toxicity and exposure and there remain large uncertainties regarding the toxicity of specific nanoparticle types, our framework focuses on exposure potential to assess product safety. As shown in Figure 1, our framework explicitly considers the several steps that typically connect nanoparticles within a product to a human exposure to free nanoparticles, including a product use or disposition that results in a release, environmental fate processes that can modify nanoparticle properties, and human exposure scenarios that bring people into contact with affected environmental media (e.g., air, water, food, soil). Central to our framework is the assessment of potential exposures along each step of the product lifecycle (e.g., from manufacture to distribution to use to end-of-life disposal), and the use of both available nanomaterial-specific data as well as data for similar materials (i.e., “bridging” data) to fill in data gaps. Our framework highlights the relationship between nanoparticle physical-chemical properties and exposure potential, and the need for repeated characterization of nanoparticle properties given that they can change along each step of a product lifecycle and in the environment.