Assessing Exposure
EPA develops methods and models that use sampling data to inform risk decisions. For example, research focuses on understanding the likelihood of human exposure to contaminants by modeling and evaluating exposure pathways. Decision makers need to understand all of the potential human exposure pathways in order to make more informed remediation decisions during a contamination incident.
Exposure is contact between a contaminant and a human or ecological receptor (e.g. fish, wildlife, or other organisms). EPA considers risk to be the chance of harmful effects to human health or to ecological systems resulting from exposure to an environmental contaminant. Understanding the risks to human health from the release of contaminants is important to setting priorities, predicting and preventing contamination incidents, and responding quickly and effectively to save lives during and after an incident.
EPA is particularly interested in the risk posed by exposure to contaminants that could be adapted to be used as weapons. These include chemical (including biotoxins), biological (including microbial pathogens), and radiological agents that might contaminate structures, outdoor areas, or water systems during and after a release.
EPA assesses information on the exposure and toxicity of chemical, biological, and radiological (CBR) agents with risk assessments that characterize the nature and magnitude of their risk. As part of this assessment, researchers determine what exposure pathways exist for receptors to encounter contaminants. This is called an exposure assessment, which describes the movement of a contaminant from its source through the environment to receptors. A complete exposure pathway includes the source of the contamination, its transport through the environment (e.g., air, water, or soil), and the route by which it enters the body (generally inhalation, ingestion, or direct contact). Researchers provide information to assess exposure pathways and develop exposure modeling for CBR contaminants to support risk assessment.