Chapter 3 - Hazard and Risk Assessment of Workplace Exposure to Engineered Nanoparticles: Methods, Issues, and Carbon Nanotube Case Study

Abstract

This chapter discusses the methods and issues related to hazard and risk assessment of workplace exposure to engineered nanoparticles. Toxicology data from experimental studies in animals are frequently used in risk assessment when human dose–response data are not available. Risk assessment is a process to systematically characterize the scientific evidence of potential adverse health effects from human exposures to hazardous agents. The traditional risk assessment framework developed in the United States, and used in various forms worldwide, includes four main steps: hazard assessment, dose–response assessment, exposure assessment, and risk characterization. The design of toxicology research studies for use in risk assessment necessitates an interface between toxicology and risk assessment to develop adequate data for qualitative and quantitative analyses. Evaluating the key information needs in this process provides an opportunity to focus additional research efforts to the generation of data necessary to reduce uncertainties in estimating the hazard and risk of exposure to nanoparticles. As with workers exposed to other chemicals or particles, nanotechnology workers are likely to have the highest exposures and greatest potential for adverse health effects associated with the production of nanoparticles and their use in commercial applications. The chapter discusses the hazard and dose–response assessment steps used in the quantitative risk assessment. The exposure assessment step is needed to characterize the risk in a given population. Furthermore, a case study is presented using rat subchronic inhalation data of multiwalled carbon nanotubes (MWCNT) to illustrate the application of risk assessment methods to engineered nanoparticles using currently available data.