Final Site Information Package for National Remedy Review Board ...

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).
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