This report summarizes the second of a series of workshop meetings on methods for assessing human health risks from exposure to chemical mixtures sponsored by the Environmental Criteria and Assessment Office (ECAO) of the U.S. Environmental Protection Agency, July 12-13, 1983. The first workshop 'Approaches to Risk Assessment for Multiple Chemical Exposures' held in September, 1982 provided a basis for selecting methods to develop into risk assessment guidelines. Five issues were reviewed at this meeting: (1) inter-species conversion of dose and duration of exposure, (2) assessment of risk for less than lifetime exposure to carcinogens and to other toxicants, (3) additivity model for chemical mixtures, (4) methods for determination of acceptable daily intakes from quantal of continuous data, and (5) pharmacokinetic basis of route-to-route conversions. Working groups also produced recommendations for approaches to four additional problems: consideration of high risk subgroups, assessment of multiple routes of exposure, ranking the severity of effects and the use of exposure and monitoring data in health risk assessment. A symposium on this methodology is planned for the fall of 1984.

Distributed to despository libraries in microfiche. "June 1984." Includes bibliographical references (pages 101-103). "EPA-600/9-84-014a."