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Title: Risk assessment calculations using MEPAS, an accepted screening methodology, and an uncertainty analysis for the reranking of Waste Area Groupings at Oak Ridge National Laboratory, Oak Ridge, Tennessee. Environmental Restoration Program

Technical Report ·
DOI:https://doi.org/10.2172/10132587· OSTI ID:10132587

The Waste Area Groupings (WAGs) at the Oak Ridge National Laboratory (ORNL) were reranked with respect to on- and off-site human health risks using two different methods. Risks associated with selected contaminants from each WAG for occupants of WAG 2 or an off-site area were calculated using a modified formulation of the Multimedia Environmental Pollutant Assessment System (MEPAS) and a method suitable for screening, referred to as the ORNL/ESD method (the method developed by the Environmental Sciences Division at ORNL) in this report. Each method resulted in a different ranking of the WAGs. The rankings from the two methods are compared in this report. All risk assessment calculations, except the original MEPAS calculations, indicated that WAGs 1; 2, 6, 7 (WAGs 2, 6 and 7 as one combined WAG); and 4 pose the greatest potential threat to human health. However, the overall rankings of the WAGs using constant parameter values in the different methods were inconclusive because uncertainty in parameter values can change the calculated risk associated with particular pathways, and hence, the final rankings. Uncertainty analysis using uncertainties about all model parameters were used to reduce biases associated with parameter selection and to more reliably rank waste sites according to potential risks associated with site contaminants. Uncertainty analysis indicates that the WAGs should be considered for further investigation, or remediation, in the following order: (1) WAG 1; (2) WAGs 2, 6, and 7 (combined); and 4; (3) WAGs 3, 5, and 9; and, (4) WAG 8.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
10132587
Report Number(s):
ORNL/ER-53; ON: DE92010266
Resource Relation:
Other Information: DN: Environmental Sciences Division Publication No. 3751; PBD: Mar 1992
Country of Publication:
United States
Language:
English