an important pathway of exposure to chemicals contained in tobacco smoke and that control policies reduced exposure was a key step in the success of the public-health strategy related to smoking (active and passive). Some argue strongly that public-health professionals and clinicians would benefit from access to a large pool of well-characterized biomarkers to guide both prevention of adverse health effects and health promotion (Jackson 2005).

Biomonitoring can also serve as a valuable tool in various public-health activities aimed at avoiding the deleterious effects associated with exposure to toxic substances. From a risk-assessment and risk-management perspective, the determination of markers of internal exposure may serve a number of purposes that can be situated along a continuum of risk-assessment and -management activities (e.g., Burke et al. 1992). Four broad categories are represented here because they pertain to activities that use biomonitoring: scoping, status and trends, exposure and health research, and risk assessment. Examples of types of activities included in each category are listed in Box 3-1. Scoping is a basic risk-management activity that may provide the first indication of a potential problem. The qualitative information gathered through scoping assists in addressing fundamental questions such as, is a chemical present in the biomonitoring sample (Burke et al. 1992)? Examples of scoping include screening, exploratory and source investigations,