The rise of exposure assessment among the risk sciences: an evaluation through case studies

Controlling the exposure of human populations to environmental contaminants using a risk-based approach requires both an accurate metric for the impacts of contaminants on human health and a defensible process for selecting which exposures to control. Risk assessment is a process for identifying adverse consequences and their associated probability. The purpose of this article is to provide an overview of the evolving role of exposure assessment in the field of environmental health risk assessment. This overview is provided through a set of case studies, which provide key insight on how exposure assessments are becoming more sophisticated and more important to both the risk assessment and risk management process.

I begin with an overview of the risk assessment process, which includes hazard identification, risk characterization, risk valuation, and risk management. This overview is used to identify the risk sciences and the role of exposure assessment among the risk sciences. I next provide a summary overview of the exposure assessment process and of how it is currently practiced by regulatory agencies and health scientists. Following this is a section that describes the importance of the indoor environment in characterizing and measuring human exposure to toxic substances. I next provide three case studies that illustrate how exposure assessment has been applied in some current environmental health studies and regulations. Although these examples do not capture a full spectrum of the activities going on within the exposure assessment community, they do reveal the interaction of measurement science, theoretical studies, and regulation in the emerging discipline of exposure assessment. These studies include (1) personal air measurements for the total exposure assessment methodology (TEAM) studies, (2) multiple routes of exposure for drinking-water contaminants, and (3) the use of multimedia exposure assessments for assessing the health impacts of contaminated soils. The article ends with a summary discussion of the potential for exposure assessment as a research field.