Appendix M: Installation Narrative Summaries - denix

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Twin Cities Army Ammunition Plant (AAP) formerly
manufactured small arms ammunition and projectile casings,
and supported DoD tenants. Past waste disposal practices
released contaminants into soil, groundwater, and sediment.
Contaminated groundwater has impacted municipal water
supplies. Ammunition-related metals, volatile organic
compounds (VOCs), and polychlorinated biphenyls (PCBs) are
the primary soil contaminants at the installation. In September
1983, EPA placed the installation on the NPL. Twin Cities AAP
established a technical review committee in 1985 and a
Restoration Advisory Board (RAB) in FY96. From FY86 to
FY93, the Army installed soil and groundwater extraction and
treatment systems. The installation constructed a boundary
groundwater containment system to contain and treat
VOC-contaminated groundwater at the installation's southwest
boundary. The Army provided a groundwater treatment system
for the City of New Brighton and a municipal water supply
hookup at Lowry Grove Trailer Park. The Army, State of
Minnesota, and EPA signed a federal facility agreement (FFA)
in 1987. In FY95, the installation completed an unexploded
ordnance (UXO) sweep in support of the CERCLA site
cleanups. The Army procured a technical assistance for public
participation contract to support the RAB in FY99. The Army
completed 5-year reviews of Operable Units (OUs) 1, 2, and 3
in FY99 and FY04.
The installation grouped 25 sites, including former landfills,
burning and burial grounds, ammunition testing and disposal
sites, industrial operations buildings, and sewer system
discharge areas, into 3 OUs. To date, the Army has signed
three Records of Decision (RODs). The cleanup progress at
Twin Cities AAP for FY02 through FY05 is detailed below.
In FY02, the Army completed remedial action construction
(RA-C) fieldwork at Sites 129-3 and 129-15, and began the
RA-C reconfiguration of the Twin Cities AAP groundwater
recovery system (TGRS) for OU 2. The installation completed
the remedial design and RA workplan for Site D metals. Staged
completion of the OU 3 requirements continued. The regulators
approved a revised cleanup goal at Site G, resulting in no
further action for VOC-contaminated soil at the site. The
installation initiated design work for a cover over the dump at
Site G. The regulators approved the 135 and 535 Primer/Tracer
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Area preliminary assessments and the 135 workplan site
inspection (SI). The SI work commenced at the Building 135
Primer/Tracer Area. The Army abandoned 31 unused
monitoring wells, both on and off the installation. The regulators
approved closeout reports for the Grenade Range and the
Outdoor Firing Range.
In FY03, the Army completed RA-C fieldwork at Site A (VOC
soils), Site D (metal soils), and the removal of the corrective
action management unit (CAMU), and submitted the respective
closeout reports. The regulators approved the closeout reports
for Site 129-3 and Site 129-15, with the exception of land use
control (LUC) requirements. The regulators approved the
reconfiguration plan for the TGRS. The installation completed
the SI fieldwork for both the 135 and 535 Primer/Tracer Areas.
RA-C fieldwork began to upgrade the cover for the Site G dump
and to place a cover at the 1900 Yard Range. At Site C, the
Army obtained approval for a work plan and performed
additional characterization work. The Army commissioned a
Phase I/Phase II environmental site assessment to support
future property transfers. The Army conducted an inventory of
closed, transferred, and transferring ranges and sites with UXO,
discarded military munitions, or munitions constituents that
identified no Military Munitions Response Program (MMRP)
sites at the installation.
In FY04, the installation completed the cover construction at
Site G. The regulators approved the closeout reports for Site A
(1945 Trench) and Site D, both with the exception of LUCs, the
closeout report for the CAMU (with no LUCs), and the second
5-year review.
In FY05, Twin Cities AAP obtained regulatory approval for the
Tier II ecological risk assessment for various water bodies, and
the Army initiated a feasibility study (FS) to evaluate remedies.
Regulators also approved the closeout report for Site G (except
LUCs), the SI reports for the 135 and 535 Primer/Tracer Areas,
and an evaluation report for the vapor intrusion pathway off the
installation.
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Twin Cities AAP received regulatory approval for an
alternatives analysis addressing revised and new remedies for
Site C. A ROD Amendment was signed for OU 1, resolving
disagreements over groundwater containment and the need for
further action deeper in the aquifer. Additionally, the Army
signed another ROD Amendment for OU 3, documenting the
final decision to turn off the extraction well. Contaminated
sediment was removed from a ditch near the 135 Primer/Tracer
Area and the closeout report was approved by the regulators.
With the exception of LUCs, the regulators also approved a
closeout report for construction of a cover over contaminated
soil at the 1900 Yard Range of the Outdoor Firing Range.
Regulatory issues delayed the LUC issue resolution and ROD
amendments for various soil sites. Regulatory issues also
delayed approval and trustee concurrence for the aquatic sites
FS.
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The Army has identified no MMRP sites at this installation.
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Plan of action items for Twin Cities Army Ammunition Plant are
grouped below according to program category.
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0 Resolve LUC issues and sign ROD amendments
for various soil sites in FY07.
0 Initiate engineering evaluation and cost
analysis for 135 and 535 Primer/Tracer Areas
and Building 102 in FY07.
0 Complete the soil and sediment remedies at
Site C in FY08.
0 Obtain regulatory approval and trustee
concurrence for the aquatic sites FS in FY08.
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There are no MMRP actions scheduled for FY07 or
FY08.
M-196