Biomarkers as Tools in Human Health Risk Assessment

Evaluation of occupational or environmental risk due to exposure to chemicals requires sufficient information on the toxic profiles, mechanisms of action, toxicokinetics, dose-response relation, exposure, and the target dose. Usually exposure is estimated by measuring concentra-lions of the agent in air, food, water, soil, dust, or other media with which a population or an individual is in contact. However, this external exposure is only a rough estimate for the internal exposure (agent dose or its metabolite at the critical target in the organism). Factors of influence are bioavailability of the chemicals, variations in concentrations and routes of exposure, physical activ-ity, and individual variation in rates of metabolism, distri-bution, and excretion. All these affect the concentration of the toxic agent at the critical target, which is the mos