2.10. Statutory Determinations
- Protection of Human Health and the Environment
- Compliance with ARARs
- Cost-Effectiveness
- Utilization of Permanent Solutions and Alternative Treatment Technologies to the Maximum Extent Practicable
- Preference for Treatment as a Principal Element
Section 121 of CERCLA specifies that the selected remedial actions must comply
with all Federal and State ARARs, be cost-effective, be protective of human
health and the environment, and utilize permanent solutions and alternative
treatment technologies or resource recovery technologies to the maximum extent
practicable. In addition, the selected remedies should employ treatment that
permanently and significantly reduces the volume, toxicity, or mobility of
hazardous wastes as their principal element. The selected remedies for ground
water and the unsaturated zone are the same as those described in the PRAP and
meet these statutory requirements as discussed below.
The selected remedy for ground water will provide adequate protection of human
health and the environment through extraction of contaminated ground water and
treatment at the surface to reduce in situ concentrations below MCLs.
Discharges to the air will be designed for no measurable contaminant emissions.
In addition, further offsite migration of the contaminant plume will be
prevented. The selected remedy will reduce exposure to levels within or below
EPA's acceptable carcinogenic risk range of 10-4 to 10-7, and hazard indices
will be far below 1.0 after cleanup.
Vacuum-induced venting of the unsaturated zone will remove subsurface VOCs and
FHCs and prevent contaminant migration to ground water. Implementation of the
selected remedies will not pose unacceptable short-term risks or impact the
adjacent subsurface media, other than some lowering of water levels due to
ground water extraction. Lowering of the water table will be mitigated by
locally recharging the ground water with treated ground water.
The selected remedies will comply with all Federal and State ARARs, including
the to be considered (TBC) criteria in Appendix B. Table 1 and Table B-1 in
Appendix B list and describe the ARARs and TBCs that will be attained by each
selected remedy.
The selected remedies provide overall effectiveness proportionate to their
costs. Present worth cost estimates for each alternative are presented in
Tables 5 and 6. Although the selected remedies cost somewhat more in terms of
present worth compared to the other alternatives, they enable more rapid
cleanup.
The selected remedies utilize permanent solutions and alternative treatment
technologies to the maximum extent practicable. The selected alternatives
permanently remove contaminants from ground water and the unsaturated zone by
extraction and treatment at the surface using UV/oxidation, air stripping, GAC,
and ion exchange for ground water and catalytic oxidation for vapor. Both
selected alternatives provide the best balance of tradeoffs among the
alternatives, and use treatment technologies that destroy most contaminants,
converting them to harmless compounds.
The selected alternatives will reduce contaminant mobility more than the other
alternatives. Although the selected alternatives have a higher present worth
cost than the other alternatives, the selected alternatives will accomplish the
cleanup objectives in a shorter time period. Therefore, reducing contaminant
mobility and expediting cleanup time (short-term effectiveness) were the most
important primary balancing criteria in selecting the remedies.
For both selected alternatives, overall protection of human health and the
environment and the compliance with ARARs were also decisive factors in remedy
selection. Community concerns were included in the decision-making process by
addressing community input received at CWG meetings and during the public
comment period on the PRAP. The Responsiveness Summary, attached to this ROD,
addresses community comments on the remedial alternatives.
The selected remedial actions satisfy the statutory preference for selecting
remedies in which treatment that permanently and significantly reduces the
volume, toxicity or mobility of the contaminants is a principal element. The
selected remedial action for ground water uses treatment to address the
contaminated ground water, which is the principal medium of concern.
UV/oxidation-based technology destroys contaminants leaving residual harmless
compounds such as carbon dioxide and water. Both UV/oxidation and air
stripping-based technologies will achieve a permanent and significant reduction
of the toxicity, mobility, or volume of the contaminants. Similarly, for the
unsaturated zone, vacuum-induced venting followed by catalytic oxidation of the
extracted vapor will destroy VOCs and FHCs after removal from contaminated
soil, thereby also meeting this statutory preference.
UCRL-AR-109105
