Evaluation of Uncertainty in a Site-Specific Risk Assessment
Publication: Journal of Environmental Engineering
Volume 123, Issue 3
Abstract
An evaluation was performed of the uncertainty in predicted carcinogenic risk resulting from uncertainty in site properties and fate and transport predictions for a simple contaminated soil site. SoilRisk, a risk model for organic contaminants in soil, was applied to a case-study site consisting of sandy soil and a thin, near surface, unconfined aquifer. The site-related parameters found to affect predicted risk most significantly were the soil-water volumetric flux rate (Jw) in the unsaturated zone, the longitudinal dispersivity (αL) and the Darcy velocity (Vd) in the saturated zone, and the soil organic carbon fraction in both zones (foc, focsat). Model runs using probability distribution functions (PDFs) for these input parameters yielded cumulative distribution functions (CDFs) for the total risk estimates, the shape and location of which depended on the chemical and exposure scenario. In general, uncertainty in risk at the case-study site was found to be greater for the more mobile and less degradable of the chemicals studied [trichloroethylene (TCE) and chlordane] than for benzene, which is highly degradable, and benzo[a]pyrene (BaP), which is very immobile in the subsurface.
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References
1.
Baes, C. F. III, and Sharp, R. D.(1983). “A proposal for estimation of soil leaching and leaching constants for use in assessment models.”J. Envir. Quality, 12(1), 17–28.
2.
Dagan, G. (1986). “Statistical theory of groundwater flow and transport: pore to laboratory, laboratory to formation, formation to regional scale.”Water Resour. Res., 22(9), 120S–134S.
3.
Donigian, A. S., Yo, T. Y., and Shanahan, E. W. (1983). “Rapid assessment of potential groundwater contamination under emergency response conditions.”Rep. EPA-600/8-83-030, U.S. Environmental Protection Agency, Washington, D.C.
4.
Ebasco Services Inc. (1989). “Final remedial investigation/feasibility study, Byron Barrel and Drum Site, Byron, NY.”Rep. EPA Contract No. 68-01-7250, U.S. Environmental Protection Agency, Washington, D.C.
5.
Freeze, R. A.(1975). “A stochastic conceptual analysis of one dimensional groundwater flow in a non-uniform homogeneous media.”Water Resour. Res., 11(5), 725–741.
6.
Freeze, R., and Cherry, J. A. (1979). Groundwater. Prentice-Hall, Inc., Englewood Cliffs, N.J.
7.
Gelhar, L. W., Mantoglou, A., Welty, C., and Rehfeldt, K. R. (1985). “A review of field-scale solute transport processes in saturated and unsaturated porous media.' Rep. EA-4190 RP-2485-05, Electric Power Research Institute, Palo Alto, Calif.
8.
Grisham, J. W. (1986). Health aspects of the disposal of waste chemicals. Pergamon Press, New York, N.Y.
9.
Jury, W. A. (1985). “Spatial variability of soil physical parameters in solute migration: a critical literature review.”Rep. EPRI EA-4228, Electric Power Research Institute, Palo Alto, Calif.
10.
Jury, W. A., Russo, D., Streile, G., and Hesham, E. A.(1990). “Evaluation of volatilization by organic chemicals residing below the soil surface.”Water Resour. Res., 26(1), 13–20.
11.
Labieniec, P. A. (1994). “The risk implications of approaches for setting soil remediation goals at hazardous waste contaminated sites,”PhD thesis, Carnegie Mellon Univ., Pittsburgh, Pa.
12.
Labieniec, P. A., Dzombak, D. A., and Siegrist, R. L.(1996a). “SoilRisk: a risk assessment model for organic contaminants in soil.”J. Envir. Engrg., ASCE, 122(5), 388–398.
13.
Labieniec, P. A., Dzombak, D. A., and Siegrist, R. L.(1996b). “Risk variability due to uniform soil remediation goals.”Envir. Engrg., ASCE, 122(7), 612–621.
14.
Loague, K.(1991). “The impact of land use on estimates of pesticide leaching potential: assessments and uncertainties.”J. Contaminated Hydro., 8, 157–175.
15.
Mason, B. J. (1983). “Preparation of soil sampling protocol: techniques and strategies.”Rep. EPA/600/4-83/020, U.S. Environmental Protection Agency, Washington, D.C.
16.
Mason, B. J. (1992). “Preparation of soil sampling protocols: sampling techniques and strategies.”Rep. EPA/600/R-92/128, U.S. Environmental Protection Agency, Washington, D.C.
17.
Morgan, M. G., and Henrion, M. (1990). Uncertainty: a guide to dealing with uncertainty in quantitative risk and policy analysis. Cambridge University Press, London, England.
18.
Seinfeld, J. H. (1986). Atmospheric chemistry and physics of air pollution. John Wiley & Sons, Inc., New York, N.Y.
19.
Spiegel, M. R. (1961). Schaum's outline series: theory and problems of statistics. McGraw-Hill Book Co., Inc., New York, N.Y.
20.
Thompson, K. M., Burmaster, D. E., and Crouch, E. A. C.(1992). “Monte Carlo techniques for quantitative uncertainty analysis in public health risk assessments.”Risk Anal., 12(1), 53–63.
21.
U.S. Department of Commerce. (1968). Climatic atlas of the United States. U.S. Government Printing Office, Washington, D.C.
22.
U.S. Environmental Protection Agency (EPA). (1987). “Data quality objectives for remedial response activities: example scenario: RI/FS activities at a site with contaminated soils and groundwater.”Rep. PB90-272634, Washington, D.C.
23.
U.S. Environmental Protection Agency (EPA). (1989). “Risk assessment guidance for superfund volume I human health evaluation manual (part A).”Rep. EPA/540/1-89/002, Office of Emergency and Remedial Response, Washington, D.C.
24.
U.S. Environmental Protection Agency (EPA). (1991). “Risk assessment guidance for superfund volume I: human health evaluation manual supplemental guidance `standard default exposure factors' interim final.”Rep. OSWER Directive: 9285.6-03 (or PB91-921314), Office of Emergency and Remedial Response, Washington, D.C.
25.
U.S. Environmental Protection Agency (EPA). (1994). “Soil screening level guidance draft.”Rep. PB95-963529, Office of Solid Waste and Emergency Response, Washington, D.C.
Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 123 • Issue 3 • March 1997
Pages: 234 - 243
Copyright
Copyright © 1997 American Society of Civil Engineers.
History
Published online: Mar 1, 1997
Published in print: Mar 1997
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