Interspecies extrapolations in risk analysis.

Quantitative risk assessment for carcinogenic chemicals is usually based on data obtained in animal studies conducted at very high levels of exposure. A key issue in using such data is the extrapolation of results from animals to man. Recently, physiological pharmacokinetic models can also be used to aid in extrapolating extrapolations. The models can also be used to aid in extrapolating between routes of administration. Model results for inhalation and ingestion of tetrachloroethylene will be presented and compared to experimental data for rats and humans.