Assessing the uncertainty in uncertainty analysis: Application of stochastic uncertainty analysis to exposure assessment
- O`Connor Associates Environmental Inc., Calgary, Alberta (Canada)
- Health Canada Ottawa, Ontario (Canada)
Stochastic risk assessment methods have recently been applied to the evaluation of exposure to contaminants in the environment. Previously, deterministic approaches to the estimation of risk and exposure were typically utilized with no systematic or scientific insight into the range and distribution of the associated uncertainty or the level of conservatism incorporated into the estimate. With the rapidly evolving capabilities of computational tools, probabilistic modelling of uncertainty has become a viable and practical approach to risk and exposure assessment. The probabilistic approach provides greater insight into the exposure estimation process. However, the application of probabilistic techniques can convey a misleading sense of sophistication or refinement depending on the quality of information used in the input parameters. A recent study for Health Canada has applied probabilistic methods to the exposure estimates for several contaminants of concern in the Canadian environment. In this study, assumptions were required regarding the shape and distribution of uncertainty in a number of input parameters. The assumptions of shape themselves involve uncertainty which influences the outcome or exposure estimate. This paper evaluates the influence on the exposure estimate of shape for significant input parameters. An example of a typical contaminant exposure assessment is used to illustrate the effect of different distributions in exposure and risk assessment. The results of the exposure assessment are also compared in terms of the relative contribution of individual pathways to the overall exposure as a function of distribution shape and output level of confidence.
- OSTI ID:
- 218414
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
Similar Records
Quantifying uncertainty in environmental risk assessment
Application of quantitative uncertainty analysis for human health risk assessment at Rocky Flats