US EPA

The Environmental Criteria and Assessment Office (ECAO) in Cincinnati has developed health risk assessment methods for chronic exposure to single chemical from a single route of exposure. Risk assessments for carcinogens associated an exposure level with a particular incidence of cancer using a non-threshold model which is linear at low doses. For systemic toxicants, the no-observed-adverse-effect level (NOAEL)/Uncertainty Factor approach was used to estimate an acceptable daily intake (ADI). In order to develop methods for assessing risk from exposure to mixtures of chemicals, all relevant routes and all exposure durations must be considered. The basis of the single chemical approach is constantly updated to keep pace with developments in pharmacokinetics, species and route extrapolation, mathematical models, additivity and interaction. These and other relevant issues were addressed during a 2-day workshop on 'Approaches to Risk Assessment for Multiple Chemical Exposures' held by the U.S. Environmental Protection Agency in Cincinnati, Ohio on September 29 and 30, 1982. The workshop was attended by 50 scientists from EPA and private industry. This document presents the results of this workshop, including presentations, critiques and discussion for each of the 11 subtopics covered.

Stara, J. AND L. Erdreich. APPROACHES TO RISK ASSESSMENT FOR MULTIPLE CHEMICAL EXPOSURES. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/9-84/008 (NTIS PB84182369), 1984.

Prepared in cooperation with Dynamac Corp., Rockville, MD.