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9. Comparative Analysis of Alternatives This section compares the alternatives with one another in terms of the CERCLA threshold and primary balancing evaluation criteria required by the NCP. The purpose of this comparative analysis is to identify the relative advantages and disadvantages of the alternatives in terms of these CERCLA criteria. The comparative analysis is also designed to identify the key tradeoffs that decisionmakers must balance in the remedy selection process. Section 9.1 presents the comparative analysis of the 11 remedial alternatives, and Section 9.2 presents the comparative analysis of the two remedy protection alternatives. 9.1 Remedial Alternatives The comparative analysis of the No Action Alternative and Alternatives 3+(a) through 3+(e) is provided in Table B9-1a, and the comparative analysis for Alternatives 4+(a) through 4+(e) is provided in Table B9-1b. Key technical issues identified for comparison between the remedial alternatives included the following: • Impacted sediment accessibility. Impacted sediments located in river banks and beds are a major source of dissolved metals loading in the Upper Basin. Many of these impacted sediments are inaccessible, located under I-90 and other infrastructure or on private property. Cleanup or isolation of these impacted sediments is difficult and costly, with impacts on the local communities and the natural environment. • Time to achieve ARARs compliance. None of the alternatives are likely to attain compliance with chemical-specific ARARs immediately following implementation; a period of natural recovery is required for all the alternatives. • Availability of materials. Uncontaminated materials are required for covers, backfill, and revegetation actions included in the alternatives. Obtaining these materials in enough quantity could present challenges in implementing the alternatives and cause environmental impacts at offsite source locations. • Repository siting. Finding suitable available sites and fulfilling substantive permit requirements of action- and location-specific ARARs for siting and construction of repositories may be difficult. • Long-term management and associated costs. Overall operation and maintenance (O&M) requirements are associated with engineered controls such as repositories, groundwater containment systems, and active and semi-passive water treatment systems. • Socio-economic impacts. Construction associated with implementation of the remedy will have short-term “quality of life” and potential economic impacts for the local B9-1
SITE INFORMATION PACKAGE FOR NATIONAL REMEDY REVIEW BOARD PART B, SECTION 9: COMPARATIVE ANALYSIS OF ALTERNATIVES communities. These include increased truck traffic, dust, noise, disruption of services and recreational opportunities, and reduced aesthetic quality. In the following sections, the comparative analysis of the remedial alternatives is presented in terms of the CERCLA threshold criteria in Sections 9.1.1 and 9.1.2, and the CERCLA primary balancing criteria in Sections 9.1.3 through 9.1.7. 9.1.1 Overall Protection of Human Health and the Environment All of the alternatives, except the No Action Alternative, achieve the criterion of overall protection of human health and the environment. All of the alternatives based on Alternative 3+ rank slightly higher under this criterion than those based on Alternative 4+, regardless of which OU 2 alternative is included. The estimated implementation time frame for Alternative 4+ may be decades longer than that for Alternative 3+ and, during this time, Alternative 4+ would involve construction-related risks for workers, the community, and the environment resulting from the massive extent of long-term construction and hauling involved, which are risks that are considered to outweigh the long-term benefits of the proposed actions. Alternative 4+ would also have the greatest short-term environmental effects at offsite locations where borrow materials would be obtained. Implementation time frames are shorter for Alternative 3+, and the remedial actions are less extensive and carry fewer risks to workers, the community, and the environment. The differences in ranking under the criterion of overall protection of human health and the environment amongst the OU 2 alternatives do not outweigh the differences between Alternatives 3+ and 4+ overall. However, in balancing the overall effectiveness with shortterm risks, the ranking of the OU 2 alternatives under this criterion, from highest to lowest, is as follows: d, c, b, a, and e. The No Action Alternative ranks the lowest under this criterion because of the low level of protectiveness it would provide to human health and the environment. Remedial action effectiveness was evaluated in the FFS Report (USEPA, 2010) using both numerical groundwater models (CH2M HILL, 2007a, 2009a) and Predictive Analysis (USEPA, 2007; CH2M HILL, 2009f). In general, the groundwater models were used to estimate metals load reductions for actions involving groundwater collection, and the Predictive Analysis was used to estimate load reductions for remaining actions within the alternatives. The Predictive Analysis was initially developed to support the evaluation of alternatives in the 2001 FS Report (USEPA, 2001d), and was subsequently used to support evaluations in the Proposed Plan and ROD for OU 3 (USEPA, 2002). Documentation for the Predictive Analysis (referred to as the Probabilistic Analysis at the time) was initially provided in a 2001 Technical Memorandum titled Probabilistic Analysis of Post-Remediation Metal Loading (URS Greiner, 2001b). The Predictive Analysis was evaluated as part of the review conducted by the NAS (2005). Following the NAS review, a second technical memorandum, A Predictive Analysis for Post-Remediation Metals Loading, was prepared by USEPA (2007). This second memorandum provided clarification and additional documentation related to the Predictive Analysis, but the fundamentals of the analysis have remained unchanged since its initial development for the 2001 FS Report. To support the current effort, the Predictive Analysis has been updated to include data through August 2009 and modified to include the remedial actions that comprise the remedial alternatives in the FFS Report (USEPA, 2010). B9-2
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United States Environmental Protect
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Contents Acronyms and Abbreviations
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SITE INFORMATION PACKAGE FOR NATION
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Acronyms and Abbreviations µg/dL m
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RAO remedial action objective RI/FS
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Rose Lake ll n e §¨¦ 90 DUDLEY "
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1992-1994 Removal of tailings and c
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The box plot shows the median or 50
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! ( ! ! ( ! ! ! Upper Basin Coeur d
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DUDLEY ") §¨¦ 90 ") St Joe River
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Base Map Data: NHDPlus (Rivers, Wat
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[Two Updated Updated Woodland Ecolo
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Ninemile Creek WALLACE BUNN Upper B
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OSBURN §¨¦ 90 Upper Basin Coeur
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176 E Upper Basin Coeur d'Alene Riv
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§¨¦ 90 ENAVILLE The Bunker Hill
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E 169 §¨¦ 90 Upper Basin Coeur d
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TABLE B2-1 Summary of Ongoing Data
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TABLE B4-2 Screening Level Exceedan
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TABLE B7-1 Preliminary Remediation
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TABLE B8-1 Descriptions of Typical
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TABLE B8-2 Summary of Alternatives
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TABLE B9-1a Comparative Analysis of
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TABLE B9-1b Comparative Analysis of
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TABLE B11-1 Legend of Bureau of Lan
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TABLE B11-1 Legend of Bureau of Lan
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TABLE B11-2 Summary of Estimated Po
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TABLE B11-4 Summary of Remedy Prote
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TABLE B14-1 Estimated Costs Summari
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TABLE B14-2 Summary of Estimated Co
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TABLE B14-2 Summary of Estimated Co
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