Health Risk Ranking Framework for the Life Cycle of Nanomaterial-Containing Products

A.K. Madl, K. Unice, M. Kreider, M. Kovochich, I.G. Bebenek
ChemRisk, LLC, US

Keywords: risk assessment, hazard ranking, toxicity

Summary:

The diverse use of nanomaterials in occupational, consumer and environmental settings warrants a significant need for risk assessment tools for hazard and health risk evaluations. A hierarchical risk ranking framework was developed to identify and prioritize hazards and health risk scenarios involving nanomaterials. A hazard classification scheme was established based on the 1) location of the nanoscale structure in the system or matrix, and 2) intrinsic nanomaterial physical and chemical properties. Utilizing a control banding framework, a numerical risk ranking was derived based on a customized hierarchical scheme of product and nanomaterial characteristics, use and exposure patterns, and toxicological information. The sensitivity of the assumptions used and the numerical score for risk ranking were also assessed. Several parameters were apparent as primary drivers for influencing the risk ranking estimates, including releasibility from the system or matrix, exposure pathway and intensity, bioavailability, biopersistence, and severity of health effects. There were evident differences in hazard ranking between nanostructured materials of similar elemental composition but different morphologies. This framework offers a novel hazard/risk ranking approach that applies information about the parent product and substructure, use and exposure propensity, and physicochemisty that influences toxicity throughout the nanomaterial lifecycle.