Human exposure assessment and public health.

The scientific basis for public and private actions to ameliorate environmental health risks is the suspected or verified link between environmental exposures and human health effects. Exposure information is a key parameter, along with data on dose-response relationships, in determining which environmental health risks are unacceptable. Moreover, human exposures are the standard by which we judge the success of measures to prevent or reduce those risks that are deemed unacceptable. The concept of "total human exposure" has gained credence as a useful and viable framework by which to assess environmental exposures. It places exposures in the context of the continuum beginning with pollutant emissions to the environment and ending with human health consequences. The advent of biologic exposure markers, as well as effects and susceptibility markers, promises the opportunity to more accurately characterize total human exposures for environmental contaminants; thereby enhancing the quality of health risk assessments. The U.S. Environmental Protection Agency plays a significant role in the validation, application, and interpretation of biologic markers, with a lesser but important role in their development. Because the Agency is involved in virtually all phases of the biologic markers issue, EPA scientists have identified important research questions and developed plans to address those questions over the next several years. The EPA is positioned to promote the science necessary to bring biologic markers to bear on environmental issues and to interpret the results for risk assessment, risk management, and risk communication.