Acute Exposure Human Health Risks from the Accidental Release of Hazardous Substances. H. M. Hartmann and A. J. Policastro, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439
Much of the focus of human health risk assessment to date has been on modeling effects of long-term lowlevel exposures. U.S. Environmental Protection Agency (EPA) guidance has generally addressed this type of risk assessment. However, the need for risk assessment for acute chemical exposures from the accidental release of hazardous chemicals has recently been receiving more attention. We have developed methods to assess these acute exposures that address the following issues: (1) identification of human health end points of concern (e.g., potential for fatality, sublethal effects, carcinogenicity); (2) determination of exposure levels that correspond to these health end points; (3) identification of the potentially exposed populations of concern (e.g., industrial employees and the general public); and (4) exposure assessment, including air dispersion modeling. These methods have been employed in assessing transportation risks for a U.S. Department of Energy complex-wide evaluation of hazardous waste management alternatives and in assessing the risks of ongoing industrial operations at a U.S. Department of Defense site. The presentation will detail the methods developed by the authors for these risk assessments. Particular attention will be given to establishing air concentrations corresponding to health effect end points for a wide variety of chemicals. The methods used to establish these concentration levels are of particular interest because criteria levels established by the EPA (i.e., reference doses and slope factors) required some modification for application to acute exposures, and because no EPA criteria values are available for many of the chemicals with the highest potential for acute inhalation toxicity.
Work supported by the U.S. Department of Energy, Assistant Secretary for Environmental Management, under contract W-31-109-Eng-38.