Standardized approach for developing probabilistic exposure factor distributions

Journal Article · Sat Mar 01 04:00:00 EST 2003 · Risk Analysis

OSTI ID:841695

Maddalena, Randy L ^[1]; McKone, Thomas E; Sohn, Michael D

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1. LBNL Library

The effectiveness of a probabilistic risk assessment (PRA) depends critically on the quality of input information that is available to the risk assessor and specifically on the probabilistic exposure factor distributions that are developed and used in the exposure and risk models. Deriving probabilistic distributions for model inputs can be time consuming and subjective. The absence of a standard approach for developing these distributions can result in PRAs that are inconsistent and difficult to review by regulatory agencies. We present an approach that reduces subjectivity in the distribution development process without limiting the flexibility needed to prepare relevant PRAs. The approach requires two steps. First, we analyze data pooled at a population scale to (1) identify the most robust demographic variables within the population for a given exposure factor, (2) partition the population data into subsets based on these variables, and (3) construct archetypal distributions for each subpopulation. Second, we sample from these archetypal distributions according to site- or scenario-specific conditions to simulate exposure factor values and use these values to construct the scenario-specific input distribution. It is envisaged that the archetypal distributions from step 1 will be generally applicable so risk assessors will not have to repeatedly collect and analyze raw data for each new assessment. We demonstrate the approach for two commonly used exposure factors--body weight (BW) and exposure duration (ED)--using data for the U.S. population. For these factors we provide a first set of subpopulation based archetypal distributions along with methodology for using these distributions to construct relevant scenario-specific probabilistic exposure factor distributions.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: US Department of Energy; Environmental Protection Agency Agreements DW-899-38067-01-0 and DW-988-38190-01-0 (US)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 841695
• Report Number(s): LBNL--52203
• Journal Information: Risk Analysis, Journal Name: Risk Analysis Journal Issue: 5 Vol. 24
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
DISTRIBUTION
FLEXIBILITY
RISK ASSESSMENT