01-2672. Options for Development of Parametric Probability Distributions for Exposure Factors

AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notice of availability of a final report.

SUMMARY:

The notice announces the availability of a final report, Options for Development of Parametric Probability Distributions for Exposure Factors (EPA/600/R-00/058, July 2000). This report was prepared by the National Center for Environmental Assessment, within the Office of Research and Development (EPA) at the request of the Office of Emergency and Remedial Response within the Office of Solid Waste and Emergency Response, to assist them when applying probabilistic techniques in exposure assessments. The purpose of the document is to provide procedures to fit distributions to selected data from the Exposure Factors Handbook (EPA/600/P-95/002Fa-c). The procedure includes the selection of models, estimation, assessment of fit, and uncertainty. Three exposure factors were used as test cases. These included tap water intake, inhalation rates, and population mobility. The procedures used in these three exposure factors are fairly general and applicable to other factors.

ADDRESSES:

The document will be made available electronically through the National Center for Environmental Assessment's web site (www.epa.gov/​ncea). A limited number of paper copies will be available from the EPA's National Service Center for Environmental Publications (NSCEP), P.O. Box 42419, Cincinnati, OH 45242; telephone: [phone] or 513-489-8190; facsimile: 513-489-8695. Please provide your name and mailing address and the title and EPA number of the requested publication.

FOR FURTHER INFORMATION CONTACT:

Jacqueline Moya, National Center for Environmental Assessment-Washington Office (8623D), U.S. Environmental Protection Agency, Washington DC 20460; telephone: [phone]; facsimile: 202-565-0076; email:[e-mail].

SUPPLEMENTARY INFORMATION:

Since the publication of the Exposure Factors Handbook (EPA/600/P-95/002Fa-c) in 1997, users of the Handbook have commented on the need to fit distributions to the data in the Handbook to assist them when applying methods to express assessments. This report is issued as a companion document to the Exposure Factors Handbook.

The methodology presented in the document was tested with three exposure factors: tap water, inhalation rates, and population mobility. However, the document provides a discussion on the applicability of this methodology to other exposure factors in the Exposure Factors Handbook.

The report discusses the pertinent statistical concepts and theory used and how they apply to the methodology developed for the fitting of distributions. The methodology models, estimation, assessment of fit, and uncertainty.

Dated: December 22, 2000.

Bruce Rodan,

Director, National Center for Environmental Assessment.