PB95-964202
EPA/ROD/R06-95/092
March 1996
EPA Superfund
Record of Decision:
v
Longhorn Army Ammunition Plant,
(Burning Ground 3), TX
5/12/1995
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012631
RECORD OF DECISION
FOR
EARLY INTERIM REMEDIAL ACTION
AT
BURNING GROUND No. 3
LONGHORN
ARMY AMMUNITION PLANT
KARNACK, TEXAS
MAY 1995
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012682
RECORD OF DECISION
CONCURRENCE DOCUMENTATION
FOR
EARLY INTERIM REMEDIAL ACTION
AT BURNING GROUND NO. 3
LONGHORN ARMY AMMUNITION PLANT
JNACK, TEXAS
Lisa Marie Pr[6e
Remedial Project Manager
ROD Peer Review Committee
Michael C. Barra
Assistant Regional Counsel
Hitt
Superfund Texas Enforcement Section Chief
' Sam Becker
Superfund Enforcement Branch Chief
Walter Sufyon
Regional Counsel
All^n M. Davis
Hazardous Waste Management Division Director
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012683
DECLARATION
BURNING GROUND No.3
LONGHORN ARMY AMMUNITION PLANT
RECORD OF DECISION
EARLY INTERIM REMEDIAL ACTION
FEBRUARY 1995
A. SITE NAME AND LOCATION
Burning Ground No. 3, Longhom Army Ammunition Plant
Kamack, Texas
B. STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected Early Interim Remedial Action for the Burning
Ground No. 3 site (the site), Longhorn Army Ammunition Plant, in Kamack, Texas. This
selection is made in accordance with the Comprehensive Environmental Response, Compensation
and Liability Act of 1980 (CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA) and, to the extent practicable, the National Oil and
Hazardous Substances Pollution Contingency Plan (NCP). This decision is based on the
administrative record for this site.
The State of Texas concurs with the selected remedy. A copy of the concurrence letter is
attached.
C. ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare, or the environment.
D. DESCRIPTION OF THE SELECTED REMEDY
The Record of Decision for the site addresses an Early Interim Remedial Action. This Early
Interim Remedial Action is necessary to mitigate potential risks posed by the high concentrations
of chlorinated solvents and heavy metals in the shallow groundwater and buried source material
at the site. The selected remedy addresses the principal risk at the site by reducing or
preventing further migration of contaminants into deeper groundwater zones and possibly surface
water bodies.
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012684
The major components of the selected remedy include:
• Extraction and Treatment of contaminated shallow groundwater using Organic Air Stripping
and Off-gas Treatment and Metals Precipitation, and
• Excavation and Treatment of Source Material using Low Temperature Thermal Desorption
and Catalytic Oxidation for off-gas.
E. STATUTORY DETERMINATIONS
This Early Interim Remedial Action is protective of human health and the environment, complies
with Federal and State applicable or relevant and appropriate requirements for this limited-scope
action, and is cost effective. Although this Early Interim Remedial Action is not intended to
fully address the statutory mandate for permanence and treatment to the maximum extent
practicable, this Early Interim Remedial Action utilizes treatment and thus is in furtherance of
the statutory mandate.
Because this action does not constitute the final remedy for the site, the statutory preference for
remedies that employ treatment that reduces toxicity, mobility, or volume as a principal element,
(although partially addressed in this remedy) will be addressed by the final response action.
Subsequent actions are planned to address fully the threats posed by the conditions at this site.
Because this remedy may result in hazardous substances remaining on site above health-based
levels, a review will be conducted to ensure that the remedy continues to provide adequate
protection of human health and the environment within five years after commencement of the
remedial action. Because this is an Early Interim Remedial Action ROD, review of this site and
of this remedy will be continuing. The development of final remedial alternatives for the site
will also continue.
J&ie Saginaw ) j Date
Regional Administrator
EPA Region 6
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012685
Signature sheet for the foregoing Burning Ground No. 3 Record of Decision between the
Department of the Army and the U.S. Environmental Protection Agency, with concurrence by
the Texas National Resource Conservation Commission.
_
'Lewis D. Walker , Date
Deputy Assistant Secretary of the Army (I, L, & E)
Environment, Safety and Occupational Health
Lawrence J. Sowa Date
Lieutenant Colonel, U.S. Army
Commander, Longhorn Army Ammunition Plant
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012686
TABLE OF CONTENTS
A. Location and Description 1
B. Site History and Enforcement Activities 5
C. Highlights of Community Participation 7
D. Scope and Role of Response Action 7
E. Summary of Site Characteristics 8
F. ... Summary of Site Risks . 12
G. Description of Alternatives 15
H. Summary of Tie Comparative Analysis of Alternatives 20
Criteria 20
Analysis . 20
Overall Protection of Public Health
and The Environment 20
Compliance with Applicable or Relevant and
Appropriate Requirements 20
Long-Term Effectiveness or Permanence 20
Reduction of Toxicity, Mobility, or Volume
of Contaminants 20
Short-Term Effectiveness 20
Implementability 20
Cost 20
Regulatory Acceptance 20
Community Acceptance 20
I. The Selected Remedy 24
J. Statutory Determination 28
Protection of Human Health and The Environment 28
Compliance with Applicable or Relevant and
Appropriate Requirements 29
Chemical-Specific ARARS 29
Action-Specific ARARS 29
Location-Specific ARARS 30
Cost Effectiveness .30
Utilization of Permanent Solutions and Alternative
Treatment Technologies of Resource Recovery
Technologies to the Maximum Extent Practicable 30
Preference for Treatment as a Principal Element 31
K. Documentation of Significant Changes 31
APPENDIX A, The State of Texas, Letter of Concurrence A-l
APPENDIX B, Responsiveness Summary B-l
APPENDDC C, Index of Administrative Record C-l
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012687
DECISION SUMMARY
A. Location and Description
Longhorn Army Ammunition Plant (LHAAP) is located in central east Texas in the northeast
corner of Harrison County, approximately 14 miles northeast of Marshall, Texas, and
approximately 40 miles west of Shreveport, Louisiana as shown on Figure 1. The installation
occupies 8,493 acres between State Highway 43 and the western shore of Caddo Lake and is
accessed by State Highways 43 and 134.
Burning Ground No. 3 is a fenced 34.5-acre secured area located in the southeastern quadrant
of LHAAP, as shown on Figure 2. Harrison Bayou flows within 1,000 feet of the western edge
and within 500 feet of the northern edge of the site.
LHAAP is situated on gently rolling land with an average slope of 3 percent towards the
northeast Most of the terrain slopes 3 percent or less, but slopes as steep as 12 percent are
common in the western and northwestern portions of the installation and along the Harrison
Bayou floodplain. Elevations on LHAAP vary from 335 to 170 feet above mean sea level (msl).
Burning Ground No. 3 is situated on a natural topographic high slightly west of the crest of a
small topographic divide between Harrison Bayou and Saunder's Branch (Figure 3). The
topography of the site has been greatly altered by operations conducted over the past 35 years.
Ground surface elevations across the site vary from 206 feet to about 174 feet msl.
LHAAP is located in a region that is commonly called the Pineywoods, a deep inland extension
of the Gulf Coastal Plain that extends into Texas, Louisiana, Arkansas, and Oklahoma. The
area is characterized by mixed pine-hardwood forests that cover gently rolling to hilly terrain.
Mild temperatures and ample rainfall in East Texas provide excellent conditions to support an
abundant and diverse plant community. This, in turn, provides a number of niches for a rich
faunal community. LHAAP is forested with loblolly and shortleaf pines, a variety of oaks,
sweet gum, black tupelo, ash, bald cypress, and a few scattered willows. Pines predominate
throughout the installation. Burning Ground No. 3 is a cleared area within a heavily wooded
section of LHAAP.
Caddo Lake, Caddo Lake State Park, and the small unincorporated town of Karnack border
LHAAP. Other surrounding land is forested, with an oil and natural gas field located to the east
of LHAAP along the Louisiana border. Caddo Lake State Park is located approximately 2.8
miles west-northwest of the installation. Other recreational facilities and nearby lake shore
communities are within five miles. The town of Uncertain is 1.9 miles north of LHAAP.
All surface water from LHAAP drains into Caddo Lake via four drainage systems that cross
portions of the installation, as shown on Figure 3. These systems are known as Saunder's
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' 012688
OKLAHOMA
TEXARKANA
TEXAS
ARKANSAS
LOUISIANA
US Army Corps
of Engineers
Tulsa District
REGIONAL LOCATION MAP
.LONGHORN ARMY AMMUNITION PLANT
KARNACK. TEXAS
FIGURE
NUMBER
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012689
o aooo
APPRQX. SCALE IN FEET
US Army Corps
of Engineers
R; Tulsa District
LOCATION MAP
FOR BURNING GROUND No. 3
LONGHORN ARMY AMMUNITION PLANT
KARNACK. TEXAS
FIGURE
NUMBER
2
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012690
DRAINAGE BASIN
DIVIDES
0 2000 4000
APPROX. SCALE IN FEET
US Army Corps
of Engineers
Tulsa District
DRAINAGE BASINS
LONGHORN ARMY AMMUNITION PLANT
KARNACK, TEXAS
FIGURE
NUMBER
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012691
Branch, Harrison Bayou, Central Creek, and Goose Prairie Bayou. The surface drainage at
Burning Ground No. 3 occurs in all directions, but is generally directed towards Harrison Bayou
to the west and to the north by both natural and man-made ditches and drainage swales.
Harrison Bayou eventually drains into Caddo Lake, which is located approximately 1 mile
downstream from the site. The extreme western corner of Burning Ground No. 3 is located
within the 100-year floodplain of Harrison Bayou.
LHAAP, including Burning Ground No. 3, is situated on an outcrop of the Wilcox Group, which
crops out over a large part of the eastern half of Harrison County. The Wilcox consists mostly
of fine- to medium-grained sands interbedded with a considerable amount of clay and seams of
lignite. The Wilcox Group is underlain conformably by the predominantly calcareous day of
the Midway Group. Regional dip of the Wilcox is to the northwest into the East Texas syncline,
while the ground surface generally dips gently to the southeast
The Wilcox Group has been identified by the Texas Water Development Board as the basal unit
of the regional Cypress aquifer, also known as die Carrizo-Wilcox aquifer. The Cypress aquifer
outcrops over most of Harrison County and is comprised of, in ascending order, the Wilcox.
Group, the Carrizo Sand, the Reklaw Formation, and the Queen City Sand. All units are
believed to be hydraulically connected. All of these units dip ,to the northwest into the East
Texas syncline.
The availability of ground water in Harrison County is largely dependent on the hydrologic
characteristics of the units comprising the Cypress aquifer. The Wilcox Group, outcropping in
the area of LHAAP, yields small (less than 50 gallons per minute (gpm)) to moderate (50-500
gpm) quantities of fresh water to wells throughout the county. As the basal unit of the Cypress
aquifer, the Wilcox is also considered as the base of fresh water in the area. The Midway
Group, which does not yield usable quantities of water, tends to serve as a relatively
impermeable basement to the overlying water-bearing Wilcox.
Burning Ground No. 3 is situated over the regional Cypress aquifer. Evidence obtained from
geophysical logs run in deep stratigraphic test borings drilled during previous investigations at
the site suggest that the contact between the Wilcox and Midway Groups occurs anywhere from
an approximate elevation of 80 feet msl immediately east of the burning grounds area to
approximately 25 feet msl on the western side of the site.
B. Site History and Enforcement Activities
LHAAP is a government-owned, contractor-operated industrial facility under the jurisdiction of
the U.S. Army Armament, Munitions, and Chemical Command. Its primary mission is to load,
assemble, and pack pyrotechnic and illuminating/signal ammunition and solid propellant rocket
motors.
Longhorn Army Ammunition Plant was established in October 1942 with the primary mission
of producing trinitrotoluene (TNT) flake in the Plant 1 area. Production of TNT continued
through World War n until August 1945 when the plant went on standby status until February
1952. Pyrotechnic ammunition as photoflash bombs, simulators, hand signals, and tracers for
40mm were manufactured at LHAAP from 1952 until 1956. Plant 3 area rocket motor facility
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012692
began operation in November of 1955. Production of rocket motors continued to be the primary
mission of LHAAP until 1965, when the production of pyrotechnic and illuminating ammunition
was re-established.'
Recent operations consist of compounding pyrotechnic and propellant mixtures, load, assemble
and pack activities, accommodating receipt and shipment of containerized cargo, and the
maintenance and/or layaway of standby facilities and equipment as they apply to mobilization
planning. The installation has also been responsible for the static firing and elimination of
Pershing I and n rocket motors in compliance with the Intermediate-Range Nuclear Force (INF)
Treaty in effect between the United States and the former Soviet Union.
Burning Ground No. 3 has been in operation since 1955. The site has been used for the
treatment, storage, and disposal of pyrotechnic and combustible solvent wastes by open burning,
incineration, evaporation, and burial. Historical waste management units include open burning
pits, an unlined evaporation pond (UEP), stockpiles of solvent soaked sawdust, and suspected
waste burial pits. The UEP was constructed at the burning ground in 1963 as a holding pond
to store wastes resulting from the washout of rocket motor casings. In 1973, the UEP also
began receiving wash water containing solvent residues and solids collected from LHAAP
operations involving pyrotechnic material preparation and mixing. These residues and solids
commonly contained the metallic cations aluminum, arsenic, barium, cadmium, chromium, iron,
lead, magnesium, sodium, strontium, and zinc; the nonmetallic anions nitrite, nitrate, and
phosphate; and the organic solvents acetone, ethyl alcohol, methyl ethyl ketone, methylene
chloride, trichloroethylene, and toluene. Sawdust soaked with methylene chloride and other
solvents that were used to clean and scour mixers used for mixing illuminants were stockpiled
along the southern berm of the UEP and were burned in trenches in the western portion of the
burning ground. An Air Curtain Destructor was built in 1979 in the western corner of the
burning ground for the purpose of disposing of explosive-contaminated wastes by burning. Use
of burn pits and trenches was reportedly discontinued in 1984. Use of the UEP was
discontinued in 1984 when it was discovered that the pond was contaminating ground water
beneath the site. The UEP was closed as a Resource Conservation and Recovery Act (RCRA)
interim status surface impoundment in 1986 by removing all waste and capping the
impoundment. As part of the INF Treaty activities being conducted at LHAAP, a bum cage was
added in 1989 for the open burning of Pershing H missile motors, from 1989 to 1993.
As part of the U.S. Army Installation Restoration Program, the LHAAP began an environmental
investigation of current and previously used waste disposal sites in 1976. The LHAAP
installation was added to the National Priorities List (NPL) on August 30, 1990. After being
listed on the NPL, LHAAP, The U. S. Environmental Protection Agency (EPA) and the Texas
Natural Resource Conservation Commission (TNRCC) - formerly known as the Texas Water
Commission (TWC) - entered into a Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA) Section 120 Agreement for remedial activities at the facility. The
CERCLA Section 120 Agreement, referred to as the Federal Facility Agreement (FFA), became
effective on December 30, 1991.
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012693
C. Highlights of Community Participation
The U.S. Army, EPA, and TNRCC have provided significant public outreach to the community
surrounding LHAAP concerning the Burning Ground No. 3. The outreach program has
included: fact sheets, media interviews, site visits, invitations to attend monthly technical and
regulatory review meetings, and public meetings.
Copies of the Administrative Record documents have been made available to the public at
several information repository locations including: LHAAP, EPA Region VI Library, TNRCC,
and Marshall Public Library. The Proposed Plan for the Early Interim Remedial Action was
released to the public on September 8, 1994. Copies of the Proposed Plan were placed at the
Karnack Post Office, Marshall Library, Uncertain City Hall, and LHAAP. A public comment
period was designated from September 11, 1994 to October 11, 1994. In addition, a public
meeting was held at the Karnack High School on September 15, 1994, to present the Proposed
Plan and to solicit public comments on the Early Interim Remedial Action at Burning Ground
No. 3 of LHAAP. The U.S. Army placed notices of the meeting in the local newspaper and
public buildings, and distributed fact sheets describing the Proposed Plan to local officials and
hundreds of local citizens.
Representatives of the U.S. Army, EPA and TNRCC answered several questions at the public
meeting. Seventy one written comments were received during the public comment period.
These comments and those expressed at the public meeting are addressed in the Responsiveness
Summary report which is attached to the ROD as Appendix B.
D. Scope and Role of Response Action
The investigations at the Burning Ground No. 3 site have indicated the presence of high
concentrations of chlorinated solvents and heavy metals in the shallow groundwater and buried
waste. Increasing concentrations of contaminants have been detected in the groundwater
monitoring wells at the site, and the contaminated shallow groundwater plume has increased in
lateral extent over the past several years. The close proximity of the site to Harrison Bayou and
Caddo Lake creates conditions conducive to the introduction of contaminants to these aquatic
systems via groundwater transport. Consequences of this scenario could potentially include
contaminant exposure to human and ecological receptors associated with these important aquatic
resources.
The Early Interim Remedial Action is necessary to address and mitigate potential risks associated
with the high concentrations of contaminants in the shallow groundwater and their source
material. The remedial objectives for the Early Interim Remedial Action are to eliminate or
minimize the potential for exposure to human and ecological receptors. This will be
accomplished by reducing or preventing further migration of contaminants from source material
and shallow groundwater into deeper groundwater zones, and possibly surface water bodies.
The Early Interim Remedial Action will be implemented prior to completion of the site Risk
Assessment. The ongoing Remedial Investigation/Feasibility Study (RI/FS) for the Burning
Ground No. 3 site will continue as scheduled. The RI/FS will address all contaminated soil and
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012694
groundwater at the site. A final ROD will be prepared following the completion of this study/
Lessons learned during the implementation of the Early Interim Remedial Action, will be
incorporated to the. extent possible into the RI/FS. Therefore, the Early Interim Remedial
Action will be consistent with planned future actions at the site.
E. Summary of Site Characteristics
Burning Ground No. 3 is situated on an outcrop of the Wilcox Group, with a contact between
the primary materials of the Wilcox and recent alluvium running somewhere across the western
corner of the site. This contact approximates the 100-year floodplain elevation of 180 feet msl.
Although many borings have been drilled over mis entire area, stratigraphic correlation is
difficult due to the lateral and vertical heterogeneity of the materials comprising the Wilcox
Group. Subsurface data from soil borings and monitoring wells drilled and constructed as part
of past investigations of the Burning Ground No. 3 site show very few strata to be continuous
across the site area. These strata are typical for the Wilcox Group, consisting of varying
thicknesses of sands, silts, and clays that are lenticular and discontinuous in nature. Figures 4
and 5 show the locations of on-site monitoring wells and previous soil boring locations,
respectively.
Groundwater at Burning Ground No. 3 generally occurs under unconfined conditions. Depth
to groundwater, which has been measured at one foot to 23 feet beneath the ground surface, has
been observed to fluctuate approximately 2 feet over a 6-month period, reflecting the seasonal
variations in rainfall. Although groundwater elevations are known to vary seasonally, the
configuration of the groundwater surface varies little from that shown on Figure 6. The
ground water is mounded under the southern quadrant of the site in an elongated configuration
extending from the southern comer of the fenced area toward the middle of the site.
Groundwater flows in a radial pattern off Burning Ground No. 3, which contrasts with the
regional direction of flow across the area which is to the northeast. This contrast in flow
directions reflects the recharge effects of the topographically high Burning Ground No. 3.
Several investigations have been performed at the Burning Ground No. 3 site since 1976.
Existing data show that at least two known sources are contributing to the groundwater
contamination beneath the site. The primary source is the past usage of the UEP. A second
source is trenches still containing solvent-contaminated wastes in the vicinity of the Air Curtain
Destructor location. A third possible source for ground-water contamination is contaminated
soils at various burn pit locations throughout Burning Ground No. 3.
High concentrations of solvents (volatile organic compounds (VOCs)), primarily methylene
chloride and trichloroethylene, and traces of heavy metals, such as barium, have been detected
within subsurface soils, buried waste, and the uppermost water-bearing zone at the site. The
methylene chloride plume covers a larger area and has higher concentrations than the
trichloroethylene plume. This difference could be attributed to the fact that methylene chloride
is more soluble in water, more mobile, and is less likely to be absorbed to the soil than
trichloroethylene. The concentrations of methylene chloride, as of April 1994, range from
approximately 10,550 mg/1, near the center of the plume, to less than 0.005 mg/1, near the
northwest edge of the plume. The concentrations of trichloroethylene, as
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012695
C-5
C-6
•C-4A
AMO-4
C-J
O
'-21
UW13
AIR CURTAIN
DESTRUCTOR
130
REV. 1 ADDED EW-t 4/20/94
C-1
200
400
rffr
SCALE IN FEET
C-9
C-10
6-8
US Army Corps
of Engineers
Tulso District
MONITORING WELLS
BURNING GROUND No.3
LONCHORN ARMY AMMUNITION PLANT
KA3NACK. TEXAS
FIGURE
NUMBER
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012696
LEGEND
H EXISTING WJNITORING VELLS
© PREVIOUS SOIL BORING
(8A-9 PREFIX WAS LEFT OFF BORING
^ IDENTIFICATION FOR CLARITY).
( SOURCE UNITS
N
\
LEGEND OF SOLVENT CONCENTRATIONS
IN MICROGRAMS PCR KILOGRAM Cup/kg)
AV/D4S
:ALE IN FEET
0 £ 500000 (up/kg)
A i IOOAOO mooo (ug/kg)
• >. LOGO (ug/kg>
-f- >_SOO
LQNGHORN ARMY AMMUNITION PLANT
KO04MX TEXAS
BURNING GROUND No. 3
FIGURE 5
PAST SOIL INVESTIGATIONS
CONCENTRATIONS OF VOCs
S. ARMY ENG1NCER DISTRICT
CORPS OF ENGINEERS
tULSA, OKLAHOMA
DESIGNED BY.
V.D. LANIER
DRAVN BY.
C.
10
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012697
C-6
LEGENBi
•C-10 MONITORING VELL
175 GROUNDVATER ELEVATION
CONTOURS (Feet nsl)
»C-7
LDNGHORN ARMY AMMUNITION PLANT
KCRNMX TEXAS
BURNING GROUND No. 3
FIGURE 6
GROUNDVATER CONTOURS
APRIL 1994
Jl S. «MT OGtfCOt D1STWCI
msn or ENCNTRS !9'*0'<|
!u.«, i
KS1WCO IT.
VJL LAN1CR
DRAVN IT.
* VO.LS
11
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012698
of April 1994, range from approximately 1,520 mg/1 near the center of the plume, to less than
0.005 mg/1 near the northwest edge of the plume. Figures 7 and 8 show the isoconcentration
contours of the methylene chloride and trichloroethylene plumes, respectively, as,of April, 1994.
Ground water monitoring results have indicated the potential presence of methylene chloride and
trichloroethylene in a free-phase in the shallow groundwater beneath Burning Ground No. 3 to
the south and west of the UEP and in the vicinity of the Air Curtain Destructor. Since these
chemicals have a density that is greater than water, the free-phase of these compounds is also
referred to as dense nonaqueous phase liquids (DNAPLs). There is ho evidence of light
nonaqueous phase liquids at the site.
From 1987 through 1989, 174 soil samples were analyzed for VOCs. Trichloroethylene was
detected in 103 samples with a maximum concentration of 1,000 mg/kg. Methylene chloride
was detected in 64 samples with a maximum concentration of 742 mg/kg. Acetone was also
detected in 38 of the 174 samples with a maximum concentration of 33 mg/kg. These VOCs
were also detected in samples collected from potential source areas for the treatability studies
program conducted in December 1993. Buried saw dust was encountered during the treatability
studies sampling in the area adjacent to the southeast comer of the Air Curtain Destructor.
Barium, chromium, and lead have also been detected in site soil samples at concentrations
exceeding expected background concentrations (verification of background concentrations is on-
going) for the area. Known soil and debris source material locations based on the review of a
historical aerial photograph and soil sampling and testing results are shown on Figure 5.
Based on the soil sampling results, historical information, and on materials encountered during
the installation of the Air Curtain Destructor and monitoring wells at the site, there continue to
be sources of contamination for soil and groundwater at the Burning Ground No. 3 site. The
nature and extent of the source areas are not well defined. The presence of various inactive
units including bum/demolition burial pits, a row of 18 bum pits, a heavy propellant pit, a liquid
waste sump, and waste trenches surrounding the Air Curtain Destructor have been confirmed
and are possible sources.
F. Summary of Site Risks
A risk assessment is a scientific procedure which uses facts and assumptions to estimate the
potential for adverse effect on human health and the environment from exposure to site
contaminants. The environmental or ecological risk assessment determines the present and
future impacts on ecological receptors attributable to the site in its current condition. Human
health risks are determined by evaluating known chemical exposure limits and actual
concentrations at the site as identified during sampling activities. The actual contaminant
concentrations are compared to exposure concentration known to have an adverse impact. In
the risk assessment, carcinogenic and non-carcinogenic health risks are calculated. Conservative
assumptions that weigh in favor of protecting human health are made in these calculations.
A risk assessment has not been completed for the Burning Ground No. 3 site since the true
nature and extent of contamination has not yet been completely determined. A risk assessment
will be conducted concurrently with the completion of the ongoing RI/FS work. The conclusions
and recommendations of the risk assessment will be used during the development of the final
12
-------
rf-8
100 200
\ \
300
\
SCMS m
•IjfMv-e
130,
•C-l
BC-10
BC-7
LEGEND
•C-l MMITORING VELL
-40— METHYLENE CHLORIDE
ISQCONCENTRATION CONTOURS.
MICROGRAMS PER LITER
• LONGHORN ARMY AMMUNITION PLANT
KCIWKX TEXAS
BURNING GROUND No. 3
FIGURE 7
HETHYLENE CHLORIDE CONTOURS
APRIL 1994
U S. HUT! OCMZR OIST8ICT
OKK (T CNCKDK
TU.SA. (KLMOw
KIICfCD IT.
WJ1
DBAWX IT.
A. VCLLS
13
-------
012700
— 10-— TRttX-OROETHYtOC
ISOCONCENTRATION CONTOURS
MCRQGRAHS PER LITER
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012701
response action for the site. However, ongoing plume monitoring has indicated that contaminant
concentrations in on-site monitoring wells and the plume lateral extent has increased over the
past several years. Therefore, the Early Interim Remedial Action is warranted to mitigate the
potential risks posed by the high concentrations of VOCs and heavy metals detected in both the
shallow groundwater and source material.
The high concentration of contaminants in groundwater at the site, and its close proximity to
Harrison Bayou and Caddo Lake creates conditions conducive to the introduction of contaminants
to these aquatic systems via groundwater transport Consequences of this scenario could include
contaminant exposure to human and ecological receptors associated with these important aquatic
resources. The magnitude of human and ecological exposure and associated risk estimates are
dependent upon further site characterization, and will be addressed in the site risk assessment.
G. Description of Alternatives
In order to evaluate potentially viable treatment remedial alternatives, several treatability studies
were conducted on representative samples of the source material and groundwater from
December 1993 to June 1994. An onsite pilot study, using several collection methods to
determine the most effective way to extract the shallow groundwater, was also conducted in the
spring of 1994. The results of the treatability and pilot studies are contained in the
Administrative Record of the site.
Treatability studies were conducted for various treatment technologies. Only the successful
technologies are considered as alternatives. The remaining technologies were found to be
ineffective when applied on the waste present at the site. The ineffective technologies for
groundwater included bioremediation and adsorption to activated carbon. Bioremediation was
not capable of degrading the target VOCs at significant rates. The use of activated carbon would
be cost prohibitive at the concentrations present in the groundwater.
The ineffective treatment technologies for source material included bioremediation, stabilization,
and chemical extraction. Bioremediation did not perform at a target rate of a minimum 20
percent removal. Loss of VOCs due to natural vaporization in the control sample was equivalent
to VOCs loss due to biodegradation. Compound-specific analyses confirmed with the addition
of an oxidizing enzyme, that at least some biodegradation of trichloroethylene occurred.
However, methylene chloride biodegradation was negligible.
During the course of the treatability studies, it was determined that the metals contamination in-
the source material did not leach when analyzed using the Toxicity Characteristic Leaching
Procedure (TCLP). Therefore, stabilization and chemical extraction treatability tests were not
performed for metal contamination in the source material. The alternatives presented for the
source material focus on the technologies that address only the VOCs contamination.
With all of the alternatives that involve soil treatment, approximately 50,000 cubic yards of soil
and source material would be addressed. This material would be treated to reduce the VOCs
contamination. The data collected during the treatability studies did not demonstrate that the full
scale operation of any of the appropriate treatment technologies, with the possible exception of
incineration, can attain the Land Disposal Restrictions regarding treatment standards imposed
-------
012702
under RCRA (40 Code of Federal Regulations (CFR) 268). The treatment technologies will
comply with the Land Disposal Restrictions through a Treatability Variance (40 CFR 268.44)
for the wastes, the treatment level range that will be established through the Treatability
Variance for the treatment technologies is a 90 to 99.9 percent reduction in the concentration
of the contaminants upon the completion of the treatment process. The treated soil will be used
as backfill material for the trench areas. The treated source material will be placed under a
landfill cap on the LHAAP installation.
Because all 'of the groundwater alternatives involve extraction, a pilot study was conducted to
determine the most effective technique to extract the contaminated shallow groundwater in the
spring of 1994. Three different systems of extraction were installed and used in the pilot study:
• an interceptor collection trench;
• a horizontal extraction well; and
• a vertical extraction well
Two types of flow tests were conducted on all three extraction structures; a gravity flow test
and a vacuum enhanced flow test Results of the pilot study indicated that the interceptor
collection trench was the most effective of the extraction techniques for the shallow groundwater
at the site. The vertical extraction well was also effective; however its radius of influence was
limited. The horizontal extraction well was not successful in extracting the shallow groundwater
at the site.
A combination of 5,000 feet of interceptor collection trench and eight vertical extraction wells
will be used to collect onsite shallow groundwater. These collection systems will be installed
along the perimeter and inside Burning Ground No. 3. Between 150,000 and 400,000 gallons
of contaminated shallow groundwater would be collected and treated daily during the
implementation of the Early Interim Remedial Action. The methods of effective extraction of
the shallow groundwater have been determined through the pilot study. The alternatives under
discussion present only the potential treatment methods for the extracted contaminated water.
The shallow groundwater would be treated to reduce the organic and metals contamination to
acceptable levels and discharged to the surface water.
Table 1 provides a summary description of the eight alternatives considered. All alternatives
except No-Action (Alternative 1) will include groundwater monitoring. The monitoring is
necessary to ensure that the implemented interim remedy is effective in eliminating the potential
for additional off-site migration. Alternatives 3 and 4 address the VOCs contamination, in the
groundwater. Alternatives 5 and 6 address the heavy metals in the groundwater. Alternatives
7 and 8 address the VOCs contamination in the source material.
-------
Table 1. Summary Description of The
Alternatives Considered
012703
Alternative Jl
No Action
'
Alternative 2
Limited Action
Alternative 3
Water
treatment
for volatile
organic
compounds
utilizing
ultraviolet
oxidation
Description
The No Action alternative is required by
the National Oil and Hazardous
Substances Pollution Contingency Plan
(NCP) for consideration. No Action
assumes that nothing would be done to:
• restrict site rwtt*,
• •/Mfwp? contamination; or
• fnnnftnr f}|f> i^f^tan^^mtf. migfmtinit
This alternative would not take any
actions to remove the source material or
tfw>. ffmtatnmatfA gmttiutunfor nr to
rr»ntffi| ipjgfptjnf^ ^f /«ftntflrpinfnt« jqto
clean soils or groundwater. No action
would be taken to restrict the groundwater
contaminants plume from migrating
horizontally or vertically. This alternative
would consist of long term monitoring of
the groundwater contaminant plume. The
site would be fenced and institutional
controls, in the form of deed notices and
signs, would be used to advise future
property owners and potential trespassers
of the potential health risks from
exposures trt any nf tfff. rnntaminated
media.
The laboratory treatability oxidation tests
utilized ozone, hydrogen peroxide, and
ultraviolet light (UV) to destroy organic
compounds in water. Any residual ozone
or VOCs, which may collect in the vapor
area within the UV treatment tank, are
destroyed by the catalytic air treatment
unit. The effluent water meets discharge
requirements without toxic byproducts or
air emissions. Most of the VOCs were
stripped from the water in the first 60
minutes. The VOCs were of such high
concentration that it made the air
emissions difficult to treat. This
technology is more suited to water with a
methylene chloride concentration below
10 mg/l.
Cost
pcfjm»t*H f%pit»l
Cost: $0.00
Annual Operation and
]lf«ipr*nfl|p<»; $0 00
pjrfputMf Tntnl Owls
(present worm):
$0.00
FfHnif**^ '"•pi*"1
Cost $60,000
Annual Operation and
\AfintM\anff"
$50,000
Estimated Total Costs
(present worth):
$608,000
Estimated Capital
Cost: $538,000
Annual Operation and
Maintenance:
$2,298,500
Estimated Total Costs
(present worth):
$9,500,000
Time
Estimated time of
Implementation:
Design/Remedial
Action:
0 months
Groundwater/Surface
Water monitoring:
0 years
Time of
Implementation:
.Design/Remedial
Action:
3 months
Groundwater/Surface
Water monitoring:
30 years
Time of
Implementation:
Design/Remedial
Action:
5 years
Groundwater/Surface
Water monitoring:
5 years
-------
012704
Alternative 4
Water
treatment for
VOCS utilizing
air stripping
Alternative S
Water
treatment for
metals utilizing
ion exchange
Alternative 6
Water
treatment for
metals
utilizing
precipitation
Description
Air stripping is most viable on the
extracted water. A pilot column 14 inches
in diameter and 45 feet tall with an air
flow of 100 standard cubic feet per
minute was determined. to be suitable for
achieving the desired . contaminant
removal. The test data showed at least
99.9997% removal of methylene chloride
and trichloroethylene. The air stripper off-
gas, containing VQCs would be OXidizgd
to hydrogen chloride and carbon dioxide
by a catalytic oxidizer. The gases are then
neutralized in water 'using a scrubber.
Scrubbed solutions are men used in the
groundwater treatment plant to prevent
scaling in the air stripper.
In the ion exchange process, undesirable
tons are bound to a resin then exchanged
for acceptable ions which are released to
the water. An ion exchange system was
designed to reduce the barium
concentration in .the ground-water.
Treatability tests indicate the Ion
Exchange Technology was effective in the
removal of metals from the contaminated
water at the site. The resulting waste
product may require off-site disposal.
Treatability tests were conducted using
both alum and ferric chloride as
coagulants. The water pH was adjusted
and a coagulant was added to cause the
metals to coagulate/flocculate out of the
water. In general, the ferric chloride
produced faster sedimentation and a
clearer supernatant. The precipitation
removed may require off-site disposal.
Cost
FffHmatfd Capital
Cost: $2,190,000
Annual Operation and
Maintenance;
$200,000
Estimated Total Costs
(present worm):
$3,000,000
Estimated Capital
Cost: $5,000,000
Annual Operation and
Maintenance:
$4,065.000
Estimated Total Costs
(present worth):
$20,860,000
Estimated Capital
Cost: $1.300,000
Annual Operation and
Maintenance:
$200,000
Estimated Total Costs
(present worth):
$2,080,300
Time
Time of
Implementation:
Design/Remedial
Action:
5 yean
GirtKindwater/Surface
Water monitoring:
5 yean
••
Time of
Implementation;
Design/Remedial
Action:
5 years
Croundwater/Surface
Water monitoring:
5 yean
Time of
Implementation:
Design/Remedial
Action:
5 years
Groundwater/Surface
Water monitoring:
5 years
-------
012705
Alternative 7
Soil treatment.
for
VOCs
utilizing
high.
temperature
incineration
Alternative 8
Soil treatment
for
VOCs
utilizing
low
temperature
thermal
desorption
Description
The high temperature incineration
involves the complete incineration of the
soils at a standard operating range
temperature of 914*to 1,922°F.
incineration generates a high volume of
ash and air emissions which must be
controlled. An off-gas scrubber system
will be required to handle the gases. This
system should consist of an alkaline
scrubbing media and a paniculate
suppression system, The wastewater
exiting the scrubber will be treated and
discharged in accordance with approved
water quality limits.
The low temperature thermal desorption
treatment involves the heating and mixing
of the soils at a standard operating range
temperature of 302* to 482*F. The
boiling point for water is 212*F; the
boiling points for trichloroethylene and
methylene chloride are 188* and 108*F,
respectively. This treatment technology
removes the contaminants without
changing the physical characteristics of
the soil. Off-gases would be treated using
a catalytic oxidation process. This
process will convert the solvents to
carbon dioxide, water and hydrogen
chloride gases. These gases are then
neutralized in water using a scrubber.
Scrubbed solutions are then used in the
groundwater treatment plant to prevent
scaling in the air stripper.
Cost
Pcfitnfl^ f'lpjtg]
Cost: $26,000,000
Annual Operation and
M^'ltyflMir^"
$50,000
Vet'tmatfA Total Costs
(present worth):
$26,195,000
Estimated Capital
Cost: $10,000,000
Annual Operation and
Maintenance;
$50,000
Estimated Total Costs
(present worth):
$10,195,000
Time
Time of
Imoletnentation*
UM|*»«IIB1 VIIHIIVPU.
Design/Remedial
Action:
1 year
GiDundwater/Surface
Water monitoring:
5 vears
•* JfcAAV
Time of
Implementation:
Design/Remedial
Action:
1 year
Groundwater/Surface
Water monitoring:
5 years
-------
012706
H. Summary of The Comparative Analysis of Alternatives
CERCLA regulations require that remedial alternatives be evaluated against 9 criteria to
determine which alternatives) provide the best balance between the criteria and, therefore,
should be implemented at the site. The following presents an explanation of the criteria:
1. Overall Protection of Public Health and the Environment
This criterin addresses the way in which a potential remedy would reduce, cJiminatn, or control the risks posed by
the site to human health and die environment The methods used to achieve an adequate level of protection may
be through engineering controls, treatment, techniques, or other controls such as restrictions on the future use of
the site.
2. Compliance with ARAKs
Compliance with applicable or relevant and appropriate regulations (ARARs) assures that a selected remedy will
meet all related Federal, State, and local requirements. The requirements may specify maximum concentrations
of chemicals mat can remain at a site; design or performance requirements for treatment technologies; and
restrictions that may limit potential remedial activities at a site because of its location.
3. Long-term Effectiveness or Perma
This criteria addresses the ability of a potential option to reliably protect human health and the environment over
time, after the cleanup goals have been accomplished.
4. Reduction of Toricity, Mobility, or Volume of Contaminants
This criteria assesses how effectively a proposed remedy will address the contamination problem. Factors
considered include: the nature of the treatment process; the amount of hazardous materials that will be destroyed
by the treatment process; how effectively the process reduces the toxicity, mobility, and volume of waste; and the
type and quantity of contamination that will remain after treatment.
5. Short-term Effectiveness
This criteria assesses short-term risks to the workers, the community, and the time factor. Cleanup technologies
often require several years for implementation. A potential remedy is evaluated for the length of time required for
implementation and the potential impact on human health and the environment during the remedial action.
6. Implementability
Implementability addresses the ease with which a potential remedy can be put in place. Factors such as technical
feasibility and availability of materials and services are considered.
7. Cost
Costs (including estimated capital costs required for design and construction and projected long-term maintenance
costs) are considered and compared to the benefit that will result from implementing the remedy.
8. State Accept!
The State has an opportunity to review the documents in the Administrative Record and the Proposed Plan and offer
comments. The State may agree with, oppose, or have no comment on the preferred alternatives.
9. Community Acceptance
During the public comment period, interested persons or organizations may comment on the alternatives. These
comments are considered in making the final remedy selection. The comments are addressed in a document called
Responsiveness Summary which is part of the Record of Decision.
20
-------
012707
The following is a narrative analysis for the alternatives considered:
Overall Protection of Public Health and the Environment:
With the exception of the No Action Alternative and the Limited Action Alternative for the
source material and groundwater, all of the alternatives provide some protection of human health
and the environment. Because of the need to actively address the contamination at the Burning
Ground No. 3 site, the No Action Alternative and the Limited Action Alternative will not be
carried any further in the evaluation.
Although the incineration alternative (Alternative 7) would provide the highest degree of overall
protection for the source material, the high temperature destruction capability of an incinerator
is not necessary for the wastes from the Burning Ground No. 3 site. Alternative 8 provides
overall protection in that the contaminants will be removed from the source material and treated
in the vapor stage through a catalytic oxidation unit to yield carbon dioxide and water.
A combination of either Alternative 3 or 4, which address the VOCs contamination in the
groundwater, and either Alternative 5 or 6, which address the heavy metals in the groundwater,
would provide overall protection of the environment and effective treatment of groundwater.
Compliance with Applicable or Relevant and Appropriate Requirements:
Given the source material was contaminated with spent halogenated solvents (F002) from non-
specific sources, the source material is regulated under Resource Conservation and Recovery Act
(RCRA) 40 CFR 261, Subpart D. All the alternatives that involve treatment of the source
material will have to comply with the Land Disposal Restrictions for F002 waste. The
treatability studies conducted for the incineration and thermal desorption technologies indicate
that effective reduction in the concentrations of the contaminants can be achieved; however, the
reductions do not reduce the concentrations enough to meet Land Disposal Restrictions.
Therefore, the treatment technologies will comply with the Land Disposal Restrictions through
a Treatability Variance (40 CFR 268.44) for the wastes. The treatment level range that will be
established through the Treatability Variance for the treatment technologies is a 90 to 99.9
percent reduction in the concentration of the contaminants upon the completion of the treatment
process. Alternatives 7 and 8 can comply with the treatment level established by the Land
Disposal Restrictions Treatability Variance.
Applicable, Relevant and Appropriate Requirements (ARARs) will be met by those alternatives
involving treatment. The ARARs include:
• The location of the site within a 100-year floodplain;
• The treatment requirements for air emissions; and
• The discharge criteria for the treated, water.
21
-------
012708
Long-Term Effectively or Permanence:
Although the purpose of the Early Interim Remedial Action is not necessarily to implement a
permanent remedy or a remedy that will necessarily be effective in the long-term, the treatment
technologies evaluated for the source material and the extracted groundwater permanently
address the contamination associated with these contaminated media. Therefore, all of the
alternatives involving treatment address the issue of permanence.
Reduction of Toxicity. Mobility, or Volume of Contaminants,;
All the treatment alternative meet this criteria; however, the degree of reduction achieved by
each.of the alternatives is different The incineration technology (Alternative 1) was much more
efficient and effective in the reduction of the concentration of contaminants. The thermal
desorption technology (Alternative 8) is also very effective in the reduction of the concentration
of contaminants but is more efficient in their removal since the site contaminants are destroyed
at a much lower temperature than in a high temperature incinerator.
All four groundwater treatment alternatives will meet the intent of this criteria given that the
toxicity, mobility, and volume of the contaminants will be reduced upon completion of the
treatment.
Short-Term Effectiveness:
All of the alternatives involving either the excavation or extraction of contaminated media
involve short-term risks to the workers and the potential for risk to the environment. However,
engineering controls such as collection of the surface water runoff and the minimization of air
emissions during remediation, as well as the proper control and monitoring for the workers
involved in the remediation, should reduce the risks.
Implementabilitv:
Both technologies for the treatment alternatives for the source material are readily available and
are technologies that have demonstrated their effectiveness on addressing the contamination
problems associated with the Burning Ground No. 3 site. However, administrative procedures
surrounding the implementation of the incineration alternative (Alternative 7) may make
implementation difficult. The low temperature thermal desorption application (Alternative 8)
is relatively.new. However, there are approximately 40 thermal desorption projects in various
stages of implementation across the United. States. Alternative 8 is expected to be easily
implemented with no technology related problems.
Interceptor collection trenches and vertical extraction wells have been shown to effectively draw
down the water table of the shallow groundwater, as well as produce a significant volume of
water. The performance of these extraction methods meets the goal of restricting or preventing
migration of the contaminated water horizontally and vertically. In isolated pockets of
contamination or in areas where the groundwater requiring extraction is deeper than 40 feet, it
is more efficient to utilize vertical extraction wells.
22
-------
012709
A combination of these extraction methods over the site is effective and implemehtable.
Interceptor collection trenches and vacuum-enhanced liquid extraction are technologies that have
been used historically for dewatering low permeability construction sites in the most time-
efficient manner. These extraction technologies are readily available and have been used at
numerous remediation sites, including other Comprehensive Environmental Response,
Compensation and Liability Act (CERCLA) sites.
All of the technologies for treatment of the extracted groundwater are well known and readily
available. The technology that was the most effective during the treatability study for removal
of VOCs is air stripping (Alternative 4). This is a very common technology and is readily
available from many vendors. Treatment for the off-gases would be required for any treatment
technology utilized. Metals precipitation (Alternative 6) is effective, readily available, and
commonly used for removal of heavy metals from water.
Cost:
The costs for the treatment of source materials range form $10,195,000 (Alternative 8, low
temperature thermal desorption) to $26,195,000 ((Alternative 7, Incineration). The costs for the
extraction and treatment of the shallow groundwater range from $3,000,000 (Alternative 4) to
$9,500,000 (Alternative 3) for the treatment of the organic contamination, and from $2,080,300
(Alternative 6) to $20,860,000 (Alternative 5) for the metals contamination.
Regulatory Acceptance:
The EPA and TNRCC have been provided the opportunity to review the investigation results,
treatability, pilot study data, and the Proposed Plan. Support by the State of Texas for the
selected remedy for the Early Interim Remedial Action has been documented in a letter that is
included in Appendix A.
Community Acceptance:
Community Acceptance is an important consideration in the final evaluation of the remedial
alternative. All comments received during the 30-day public comment period and at the
September 15, 1994 public meeting have been specifically addressed in the Responsiveness
Summary that is included as Appendix B. These comments have dealt with site and technology
specific concerns. Based on the comments received during the public comment period, the
community appears to support the Early Interim Remedial Action as detailed in the Proposed
Plan.
-------
012710
I. The Selected Remedy
Based on consideration of the requirements of CERCLA, the detailed analysis of the alternatives,
and public comments, the U.S. Army has determined that the most appropriate remedy for
addressing the site contaminants and meeting the remedial objectives of the Early Interim
Remedial Action is a combination of Alternatives 4, 6, and 8 as follows:
•„ Extraction of shallow groundwater and treatment using metal precipitation, air stripping
and off-gas treatment for VOCs, and
• Excavation of source material and treatment using low temperature thermal desorption
and off-gas treatment for VOCs.
The present worth, capital, and operation and maintenance costs over five years for the selected
remedy are as follows:
Capital Costs
Annual Operations &
Maintenance
Present Worth
(Total Estimated Costs)
Shallow
Groundwater
Treatment &
Disposal
$4,490,000
$400,000
$5,080,300
Source Material
Excavation,
Treatment, & On-Site
Disposal
$10,000,000
$50,000
$10,195,000
Performance Standards!
The contaminated shallow groundwater will be pumped from about 5,000 feet of interceptor
collection trenches and several vertical extraction wells. The estimated groundwater pumping
rate from all extraction points is about 150,000 to 400,000 gallons per day. The hydraulic
effectiveness of the extraction system will be evaluated by monitoring groundwater levels and
quality in the shallow aquifer during the implementation of the selected remedy.
The extracted groundwater will be treated to the levels established by TNRCC (see Table 2).
The treated water will be discharged to Harrison Bayou and/or Central Creek. The precipitated
metals will be taken off-site for disposal at an approved/licensed facility. Air emissions from
both groundwater and source material treatment processes will be in accordance with 30 TAG
116 (Texas Air Control Board Standard Exemptions). Air emissions and discharged water
quality will be monitored on a regular basis to ensure that they meet the appropriate standards.
24
-------
012711
TABLE 2
Effluent Limitations for the Discharge of Remediated Groundwater
Pollutants
Methylene Chloride
(Dichloromethane)
Trichloroethylene
1,1-DichIoroethane
1,1-DichIoroethene
(1, 1-Dichloroethylene)
1,2-Dichloroethane
Vinyl Chloride
Acetone
Chloroform
Tetnchloroethene
(Tetnchloroethylene)
Ethylbenzene
Styrene '
Toluene
Benzene
Xylene
Carbon Tetrachloride
1,1,1 Trichloroethane
1 , 1 ,2 Trichloroethane
Aluminum
Arsenic (Total)
Barium (Total)
Cadmium (Total)
Chromium (Total)
Chromium (3 +)
Chromium (6+)
Cobalt*
Iron*
Lead (Total)
Units are (pg/1)
Daily Ayerage
803
85
6633
119
85
34
1132
1708
85.4
26954
2829
1980
85
39.5
85
3417
102.5
777
365
1000
1.6
355
297
58
5433
1132
2.2
Daily Maximum
1699
181
14032
253
181
72
2395
3615
180.7
57025
5987
4189
181
83.6
181
7230
216.9
1644
772
2000
3.4
752
628
124
11495
2395
4.6
MAL
20
10 .
10
•
10
10
-
10
10
10
-
10
10
-
10
10
10
20
10
10
1
5
10
10
-
-
5
-------
01271
TABLE 2
(Continued)
Pollutants
Nickel (Total)
Manganese*
Silver (total Equivalent)
Selenium (Total)
Vanadium*
Zinc
Chlorobenzene
Hexachlorobenzene
Oil and Grease
Chemical Oxygen
Demand
Chloride
Sulfate
Units are G*g/l)
Daily Average
87
7323
1.4
5.7
1698
146
22300
0.22
N/A
N/A
See Note Below
See Note Below
Daily Maximum
184
15494
3
12
3592
310
47180
0.47
15
200
N/A
N/A
MAL
10
-
2
5
-
5
50
10
-
-
-
-
"Assumes 100% dissolved
Note: Discharge limits for Chloride and sulfate are to be based on discharge rates using the following formula:
Qs = Flow rate in the receiving stream, Harrison Bayou and/or Central Creek, in cubic feet per second (cfs).
This flow rate shall be measured at a constant location no less than 100 feet upstream from the point of
discharge of treated groundwater. Measurements will be taken daily in Harrison Bayou and Central Creek
in accordance with TNRCC's Water Quality Monitoring Manual, August, 1994.
CA = Chloride/Sulfate (ambient), 10,000 microgram/per liter (/ig/1) (from State of Texas Water Quality
Inventory)
Cc = Chloride/Sulfate criteria, 100,000 jig/1 for Chloride and 50,000 ug/1 for Sulfate (from State of Texas Water
Quality Inventory)
QE = Treated Groundwater Discharge Rate in cfs. The groundwater pumping and treatment rate shall be adjusted
as necessary in order to meet the required effluent concentration CE.
CE = Effluent Concentration (discharge limit) in jig/1.
26
-------
012713
TABLE2
(Continued)
Example; For a discharge rate of 250,000 gallons per day or 0.39 cfs, and a flow rate in the receiving stream of
4 cfs, the discharge limit for chloride would be:
(4.0)(10,000)
0.39*4.0
= 1,023,
DEFINITIONS
Daily average concentration - the arithmetic average of all effluent samples, composite or grab
as required by this permit within a period of one calendar month, consisting of at least four
separate representative measurements. When four samples are not available in a calendar month,
the arithmetic average (weighted by flow) of all values taken during the month shall be utilized
as the daily average concentration.
Daily maximum concentration - the maximum concentration measured on a single day, by
composite sample, unless otherwise specified elsewhere in the permit.
TAG reference - most of the limitations are based upon water quality standards found at TAG
307 for the protection of human health and aquatic life. The limit for Barium is from TAG 319
- Subchapter B.
MAL - the minimum analytical level. All testing must be completed utilizing EPA approved
methods which can detect the pollutant to the referenced MAL.
N/A - Not Applicable.
-------
Discharged water quality will be measured in accordance with TNRCC requirements. The
quality of the discharged water shall meet the limitations established in Table 2. The monitoring
methodology and frequency for discharged water will be in accordance with TNRCC
requirements.
Approximately 50,000 cubic yards of soil and source material, including soil excavated during
the construction of the groundwater collection system, will be excavated and treated using low
temperature thermal desorption for removal of VOCs. Field and laboratory testing would be
used for confirmation of excavation limits of source material.
The excavated soil and source material will be treated according to the requirements of the Land
Disposal Restrictions (40 CFR Part 268) under RCRA. The remedy will comply with the Land
Disposal Restrictions through a Treatability Variance (40 CFR 268.44) for die wastes. The
treatment level range that will be established through the treatability variance is a 90 to 99.9
percent reduction in the concentration of the contaminants upon the completion of the treatment
process. The treated soil will be used as backfill material for the trench areas. The treated
source material will be placed under a landfill cap on LHAAP. Air emissions from the
treatment process will be monitored on a regular basis to ensure that emissions are below the
appropriate levels.
The VOCs separated from the groundwater and source material will be catalytically converted
to carbon dioxide, water, and hydrogen chloride gases. The gases will be scrubbed using water
and sodium hydroxide (if needed) to produce a very diluted acid stream. The acid stream
resulting from groundwater treatment will be pumped to and used in the groundwater treatment
plant to prevent scaling in the air stripper. The acid, stream from source material treatment will
be neutralized to produce sodium chloride that is dissolved in the water used to scrub the acid.
This water will be discharged to Harrison Bayou and/or Central Creek if it meets the
requirements pf Table 2. If it does not meet the requirements of Table 2, this water shall be
processed through the water treatment plant, and discharged once the requirements of Table 2
are met.
J. Statutory Determination
The primary responsibility at CERCLA sites is to select remedial actions that are protective of
human health and the environment. Section 121 of CERCLA requires that the selected remedial
action for the site comply with, applicable or relevant and appropriate environmental standards
established under Federal and State environmental laws, unless a waiver is granted. The selected
remedy must also be cost-effective and utilize permanent treatment technologies or resource
recovery technologies to the maximum extent practicable. The statute also contains a preference
for remedies that include treatment as a principal element. The following sections discuss how
the selected remedy for the Early Interim Remedial Action at Burning Ground No. 3 meets the
statutory requirements even though is not designed or expected to be final.
Protection of Human Health and the Environment:
The selected remedy for the shallow groundwater and source material protects human health and
the environment. The extraction and treatment of contaminated groundwater will prevent the
28
-------
012715
lateral expansion of the plume and the migration of contaminants to lower water bearing zones
at the burning ground. The excavation and treatment of source material will prevent further
migration of contaminants into the shallow groundwater zone. This action would prevent
contamination from reaching nearby aquatic systems and consequently contaminant exposure to
human and ecological receptors associated with these systems. Based on treatability test results,
air stripping will remove sufficient VOCs from extracted groundwater to meet State of Texas
discharge standards of the VOCs present in the groundwater. The low temperature thermal
desorption remedy will remove the VOCs from the source material into gaseous state. The air
stripper and'thermal desorber off-gas containing these VOCs will be catalytically converted to
carbon dioxide, water and hydrogen chloride gases. These gases will then be scrubbed using
water and sodium hydroxide (if needed) to produce a very diluted acid stream. ThisacidwiU
be pumped back into the water treatment plant where it will be used to prevent scaling in the
air stripper. A groundwater monitoring program will be maintained during the extraction^nd
treatment process. By maintaining such a program, prevention of exposure can be assured.
There are no short-term threats associated with the selected remedy that cannot be readily
controlled. In addition, no adverse cross-media impacts are expected from the remedy.
Compliance with Applicable or Relevant and Appropriate Requirements;
The selected remedy will comply with all applicable or relevant and appropriate action-,
chemical-, and location-specific requirements (ARARs). The ARARs are presented below:
Chemical-Specific ARARs:
The waste materials have been classified as F002 hazardous waste under RCRA. Treatment
levels will be established under the Treatability Variance Procedures of 40 CFR 268.44 for the
thermal desorption treatment of soils and source material. The treatment level range that will
be established throughout the Treatability Variance for the treatment technologies is a 90 to a
99.9 percent reduction in the concentration of the contaminants upon the completion of the
treatment process.
Treatment levels for the contaminated groundwater will be in accordance with state requirements
listed in Table 2.
Metals and other treatment residuals that are hazardous wastes will be managed in accordance
with RCRA (40 CFR 261).
Action-Specific ARARs:
Water discharges to a surface body of water must satisfy the substantive ^uirement. ofthe
National Pollution Discharge -Elimination System program, 40 CFR Part 125 and 30 Texas
Administrative Code (TAG).
Air emissions from both groundwater and source material treatment processes will be in
accordance with 30 TAG 116 (Texas Air Control Board Standard Exemptions).
Occupational Safety and Health Administration requirements (29 CFR) will be applicable to the
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work conducted during the Early Interim Remedial Action.
Location-Specific ARARs:
RCRA requirements concerning location of a treatment, storage or disposal facility within a 100
year floodplain will be relevant and appropriate, as part of the Burning Ground is within a 100
year floodplain (40 CFR Part 264.18).
Texas groundwater rules (30 TAG) require restoration of contaminated groundwater, if feasible.
While no historic or archeological points of interest are known to be present at the site, should
they be discovered the procedures of the National Historic Preservation Act of 1966 (36 CFR
Part 800) will be adhered to.
Cost Effectiveness;
The selected remedy is cost-effective in achieving the objectives of the Early Interim Remedial
Action. The cost for treatment of source materials range from $10,195,000 for the selected
alternative (low temperature thermal desorption) to $26,195,000 for high temperature
incineration. Therefore, the selected remedy is most effective and least expensive. The cost for
treatment of VOCs in extracted water ranges from $3,000,000 for the selected air stripping
remedy and $9,000,000 for the ultraviolet oxidation alternative. In addition, the cost for
treatment of metals in the extracted groundwater ranges from $2,080,000 for the selected metal
precipitation remedy and $20,860,000 for the ion exchange alternative. Therefore, the selected
groundwater treatment technologies provide the greatest overall protection while being cost
effective,
Utilization of Permanent Solutions and Alternative Treatment Technologies or Resource
Recovery Technologies to the Maximum Extent Practicable:
The Early Interim Remedial Action is not designed or expected to be final remedy for the
Burning Ground No. 3 site. However, the selected interim remedy represents the best balance
of trade-offs among the other alternatives with respect to the pertinent criteria. The selected
remedy satisfies the statutory requirements of CERCLA 121(b) by:
• Being protective of human health and the environment;
• Complying with applicable, relevant arid appropriate requirements;
• Being cost-effective;
• Utilizing permanent solutions and alternative treatment technologies to the
maximum extent practicable; and
• Satisfying the statutory preference for treatment as a principal element.
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Preference for Treatment as a Principal Elemenf
This selected remedy employs the use of treatment as a principal element In addition, the
preference for remedies that employ treatment as a principal element will be addressed in the
final ROD.
K. .Documentation of Significant Changes
The Proposed Plan for the Early Interim Remedial Action at the site was released for public
comments on September 9, 1994. The Proposed Plan identified the preferred alternative to be
a combination of Alternatives 4, 6, and 8: •
• Extraction of shallow groundwater and treatment using metal precipitation, air
stripping and off-gas treatment for volatile organic compounds, and
• Excavation of source material and treatment using low temperature thermal
desorption and off-gas treatment for volatile organic compounds.
The U.S. Army reviewed all written and oral comments submitted during the public comment
period. Significant, but not fundamental, changes to proposed remedy are as follows:
• The response given to Comment Number 28 from the public meeting for the
Proposed Plan (see Appendix B, page B-9) requires revision. The response
indicated that 99% of the contaminants would be removed by the treatment
process before the off-gases are emitted into the air. This response was in
reference to the test data presented in the Proposed Plan from the treatability
study for groundwater air stripping. The response correction is that the off-gas
emitted during groundwater and soil treatment will be in compliance with the
pertinent standard exemption for air emissions listed in 30 TAG 116 (May 4,
1994).
• The water used to neutralize gases in the scrubber, of the water treatment plant,
will be used in the groundwater treatment plant to prevent scaling in the air
stripper.
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APPENDIX A
THE STATE OF TEXAS
LETTER OF CONCURRENCE
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n Hall. Chairman
i K«u, Commissioner
gy Garner. Commissioner
\ Pearson. Executive Director
TEXAS NATURAL RESOURCE CONSERVATION COMMISSION
Prelecting Texas by Reducing and Preventing Pollution
February 28, 1995
Allyn M. Davis, Ph.D., Director
Hazardous Waste Management Division
U. S. Environmental Protection Agency
Region VI
1445 Ross Avenue
Dallas, Texas 75202-2733
Re: Longhorn Army Ammunition Plant
Draft Record of Decision
Dear Dr. Davis:
We have reviewed the proposed Record of Decision (ROD) for the
Early Interim Remedial Action, Burning Ground No. 3, Longhorn Army
Ammunition Plant. We concur that the remedy described in the
February 22, 1995 ROD is the most appropriate for the site. The
selected remedy calls for extraction and treatment of contaminated
shallow ground water using organic air stripping, off-gas
treatment, and metals precipitation; and excavation and treatment
of source material using low temperature thermal desorption, and
off-gas treatment using catalytic oxidation.
We have provided information regarding the State's waste discharge
and air emission standards, which have been incorporated into the
ROD. We anticipate that adequate funding and personnel resources
will be provided through the Department of Defense/State Memorandum
of Agreement and the Federal Facility Agreement to allow our
continued participation in the remedial action.
Sincerely,
son
e Director
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APPENDIX B
RESPONSIVENESS SUMMARY
INTERIM REMEDIAL ACTION
BURNING GROUND NO. 3
LONGHORN ARMY AMMUNITION PLANT
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EARLY INTERIM REMEDIAL ACTION
BURNING GROUND NO. 3
LONGHORN ARMY AMMUNITION PLANT
This Community Relations Responsiveness Summary provides written responses to public
comments submitted regarding the Proposed Plan of Action at the Burning Ground No. 3 site.
The summary is divided into two sections:
Section I: Background of Community Invplvement and Concerns. This section provides a. brief
history of community interest and concerns raised during the remedial planning activities at the
site.
Section n: Summary of Major Comments Received. The comments (both oral and written) are
summarized. The U.S. Army responses are provided.
I. Background of Community Involvement and Concerns
The community surrounding the Longhom Army Ammunition Plant (LHAAP) is aware of the
problems associated with the Burning Ground No. 3 site. This awareness is evident by the
heavy turnout for the public meeting that was held at the Kamack High School on September
IS, 1994 and by site visits conducted by a number of local officials and community activists.
The community has not expressed any opposition to the interim action at the site. However, the
community has raised some concerns through comments made during the public meeting and
written comments provided during the public comment period. The comments received from
the community concentrated mainly on past and future exposure to site contaminants as well as
questions related to the technologies presented in the selected remedy. Several members of the
community have been supportive of the interim action as can been seen from the comments
below.
II. Summary of Major Comments Received
Public notice announcing the public comment period and invitation to public meeting was given
from September 9 to September 15,1994 , in the Marshall News Messenger a widely circulated
local newspaper. Also, thirteen hundred invitation letters and fact sheets were mailed to local
citizens on September 10,1994. The Proposed Plan of Action was released to the general public
on September 8, 1994. The public comment period began on September 11, 1994, and ended
on October 11, 1994. A public meeting was held on September 15, 1994 at the Karnack High
School. The purpose of the meeting was to discuss the proposed plan and to solicit public
comments on the interim action at the Burning Ground site. Representatives of the U.S. Army
made presentations about the interim action and answered public comments during the public
meeting. Also, representatives of the Environmental Protection Agency (EPA) and the Texas
Natural Resource Conservation Commission (TNRCC) attended the meeting and assisted in the
responses to public comments as needed.
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One hundred and fifty people attended the public meeting and at least twenty asked questions
or made comments. Two sets of written comments and questions were received during the
public comment period.
The following comments and questions were received during the public meeting. A full account
of the public meeting can be found in the public meeting transcripts which are document in the
site Administrative Record: I
1. Comment by Thdma Gary:
I want to know how much of that contamination can get into our water system right now?
Response:
The U.S. Army has no indication that there is any threat to a public water supply either
on the plant or off the plant from this source or any other source that is under
investigation at the plant
2. Comment by Carol Campbell:
Are we to assume that you have identified all areas of the approximately 8,500 acres of
this facility, or is this just a first step or will there be other, say burning ground areas,
or areas that are subject to cleanup as well as this?
Response:
The units that are presently under investigation are the known units that warranted action
at this time. If any other information comes forward that gives us reason to believe that
a site or unit requires investigation, then it will be studied and go through the same
process. We went through an investigative phase and part of that phase was interviewing
and researching past employees4of Thiokol and the prior contractors' practices. The
process is a continuing one. If there are members in the community who know
something we may have overlooked in our investigative process, we would like to know
that. As a matter of fact, one of the units that is under investigation today is a unit that
was not uncovered because of former records, but was based, on a recollection of an
employee.
3. Comment by Carol Cambell:
Approximately what percentage of the total acreage has already been checked out.
Response:
An exact figure does not exist. The U.S. Army has concentrated on centralized areas
of the facility. A rough estimate would be 2,000 acres.
4. Comment by Carol Cambell:
Since it has been going on for so long, it is quite possible that there could be pits that
trees have grown up over the last thirty four years, covered up. So, you know, this has
to be a continuing thing to check out all of the acreage.
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Response:
There has been centralized surveys done and you are right, there may be one or two
places out there that we haven't thought of or we have not had an indication of.
However, this is a continuous process as the comment suggests.
5. Comment by Carol Cambell:
Right, The U.S. Army just made a point that a former employee came forward and it
, might be that you would not have located that site otherwise. Also, there may be
empibyees that are not going to be able to come forward. My only point is I am glad
that it is a continuing thing and that this is not going to be the end.
Response:
This is not going to be the end. Obviously, we have other work to do and this is where
we are going to start
6. Comment by Cynthia McGeorge:
How safe is it to assume that only a paint remover and a degreaser are the contaminants
on the site?
Response:
Those are the principle contaminants at the site. There are metal constituents in the area
and other material, but those are the principle contaminants of concern at the site.
7. Comment by Cynthia McGeorge:
Please explain air stripping and metal precipitation.
Response:
Air stripping consists of transferring the contaminants in the water into a gas phase.
These gases are then chemically reacted to convert them into other constituents that are
not a threat.
4
8. Comment by Cynthia McGeorge:.
I understand. What is the percentage of that being successful?
Response:
The U. S. Army has been very careful to insure that a technology that is effective be
used at the site. Samples were collected and treatability studies in off site laboratories
were conducted to evaluate the effectiveness of several technologies in treating the onsite
contaminants. For the groundwater, it will be treated to the levels of the drinking water
standard.
9. Comment by Cynthia McGeorge:
Is it possible for the public to get a list of the other contaminants that are on site other
than the two primary contaminants?
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Response:
A very extensive record search to what could be found on site was conducted. Following
the search, several groundwater and soil samples were collected from the site and sent
to a laboratory for testing. The list of contaminants tested for is extensive, about twelve
hundred. The laboratory data is available in the administrative record. Few other
contaminants were encountered but in much lower concentrations. The proposed
technologies will easily address these contaminants.
10. Comment by Ted ImHoff:
Is the run-off water contained on the site now or is it allowed to disperse?
Response:
The storm water runs off the site. There is a storm water pollution prevention plan and
contaminants are managed in a controlled fashion all over the plant So, there aren't
uncontrolled releases from known sources except for those mat are permanent in the
waste water discharge system. The water is sampled and the limits of the permits are
met. Releases of any constituents to storm water anywhere on the plant are controlled.
11. Comment by Ted ImHoff:
What is the elevation of this site in relation to the hundred year flood plain?
Response:
The northwest comer of the site is inside the hundred year flood plain. However, most
of the site is above what is considered the hundred year flood plain. There is no surface
contamination at the site. The only way the run-off will be contaminated is if it conies
into contact with contaminants at the surface. They will be provisions in place for
protecting run-off during the implementation of the interim remedial action. Concerning
the ongoing activities at the burning ground, concrete pads around the bum cages have
been added recently. After every burn the ash is swept and placed in special containers.
The ash does not come into contact directly with the soil in the area.
12. Comment by Marsha Jones:
I understand that approximately three hundred million gallons of contaminated
groundwater have been identified. Is that an accurate estimate or a preliminary
assessment or what, and could you give an accurate count on the number of cubic yards
of contaminated soil there is, and then what exactly will be done with it after the thermal
desorption treatment is rendered to that contaminated soil?
Response:
In short the actual number would be somewhat problematic. The treated soil will be used
for fill material back in the excavated area. Three hundred million gallons of water is
what will be treated over the course of several years. The placement of the groundwater
extraction system will generate approximately twenty-five thousand cubic yards of
material. This material will be treated even though it may not be contaminated. This
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will be done to insure that its free of contaminants before its placed back on site.
Another twenty five thousand cubic yards of source material will be excavated and
treated to the treatability variance under the law. At a minimum it will meet 90%
removal of contaminants. The treated source material will be taken to an inactive landfill
on the plant for placement as an additional protective measure. This landfill will be
capped so that the treated material will be further protected.
13. Comment by Ted ImHoff:
What depth are we talking about with regard to shallow groundwater that you are going
to be treating?
Response:
It varies across the site because of the topography. It varies from twenty five to forty
feet in depth.
14. Comment by Larry Pinney Gee:
If I understand previous responses correctly, you make it seem that air stripping is an
experimental process, is that correct?
Response:
No, it is not experimental in the least Air stripping has existed for a long time. The
oil industry and other industries have used air stripping for many years. It has been used
for remediation at many sites. It is proven and well used technology. As a matter of
fact, all of the alternatives that were investigated include proven technologies.
15. Comment by JoAnne ImHoff:
What is the result of no action? . What would be the result of no action?
Response:
No action, is the least cost alternative. However, it is not considered an acceptable
alternative for this action because we have a known contaminant in an area and we
understand how to deal with it. Up to few years ago we could not determine where the
burial pits on site were. We think we have a good/very good idea where they are based
on the research we have done. If we had no action then, the water coming through the
soil over the next five years will also go through the contaminated material.
16. Comment by unknown:
What would be the effect on the environment?
Response:
All it would do is continue the contamination. We can go in there and clean it up and
we can retrieve the source material. That would result in stopping the infection.
Whereas, if we do nothing, we just extend it out by five years.
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17. Comment by unknown:
If you do not do anything, it would continue on for five more years, is that it?
Response:
Well, it is there. It is in the soil and it was there in 1955, 1965, or 1975, we do not
know. However, we do know where it is located and it is to everyone's advantage to
go in there and clean it up and treat it You could also say that it is there and it's
something you can get to in the normal course of the remediation. Now, understand that
the site clean-up at Longhorn may take into the year .2010. By the time we prioritize the
sites requiring action, based on funding, it could well into the year 2010 before we
address each individual site. This is one site that we think that we need to address up
front and this is one site we have a plan for and it. makes sense to do it
18. Comment by Thelma Gary:
Well, I am trying to figure out, how are you going to treat this soils that you are going
to move. You treat it and then take it and put it back. So, how are you going to go
through the process of treating it? what are you going to use to treat it?
Response:
The method of treatment is called thermal desorption. It is kind of like baking the soil
at lower temperatures but removing and destroying the contaminants. The methylene
chloride will be changed into chemical constituents that are not at all harmful, like carbon
dioxide and water.
19. Comment by Thelma Gary:
So you are cooking the soil?
Response:
Yes, we are cooking it.
20. Comment by unknown:
Is it going on at other sites across the country?
Response:
There are many defense installations that are going through the same programs. For
specifically thermal desorption, there are about forty sites where this technology is being
used right now for remedying contaminants.
21. Comment by Pete Grant:
Is it not true that you have monitoring wells around this site?
Response:
Yes, there are numerous monitoring wells on and around the site, and all over the
installation including its borders. A limited number of wells is monitored quarterly and
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the data is released to the state. There are other ongoing monitoring events that are part
of ongoing investigations. There are fifty-two wells that are dedicated to this site for
monitoring. We began about nine months ago monitoring on quarterly basis. The
monitoring data goes through a validation process as soon as we receive it in order to
make sure that the test was conducted in accordance with all the requirements of EPA
for testing. Once that process is complete, that data is placed in the administrative
record for everybody's review.
22. Comment by Pete Grant:
I would like to know how deep are these wells. Do they go into the aquifer? How deep
they are and who does this information go to, such as water supply companies?
Response:
The wells vary in depth across the site. The majority are considered shallow wells.
They are less than forty feet in depth, although some extend past that point. The well
logs, all the details about the construction of the wells, who drilled them, in accordance
with state requirements, we have to record all the data with the state. All the data is also
in the public record. As far as notification, the state and EPA have all been involved
in it. It is open to the public. Anybody that is interested, the data is in the record.
There is no indication of a threat to any public water supply, either on the plant or off
the plant. There are wells that you are probably concern with north of the plant and
. Uncertain. But there is no threat to those water systems.
23. Comment by Ruth Culver:
I am the Conservation Chairperson for the Uncertain Audubon and hopefully everyone
got one of these slips (indicating) as they came through the door.
Because of the accumulation of data from the site, one the things that the EPA does is
to allow for a TAG grant which is a technical assistance grant and it is given to citizens
groups. It is not given to a government entity. It is given for the purpose of hiring
technical assistance to help explain to the citizens of the community exactly what these
guys (U.S. Army) are doing. All the information that they collect is available for all of
us to go and look at, but it is rather difficult for some of us to be able to decipher
exactly what that information is.
Colonel (LTC) Sowa and David Tolbert (U.S. Army Longhorn Staff) have been very
generous to get us out onto the site. I had someone else with me who said, "Hey, Ruth,
this is a really clean operation here. I have been on other sites that will just really blow
your mind." These guys are really apparently out there trying to get the job done. But
with all of this data that we are being able to review, it is difficult to make heads or tails
of it. So, that is why our group is applying for this TAG fund. It is not money that will
go into the Uncertain Audubon. It is money that is accountable for. As a matter of fact
it is burdensome to some extent to apply for this because of the regulations and how we
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have to account for the money. But we felt that it was very needed for the community
just because of some of the questions posed here tonight And hopefully with this, we
will be able to bring some of you back here and say, this is what they are doing and be
able to be explained to you, to where all of can, hopefully, understand and know what
is going on.
So, if there are any other groups that's here, tonight that is interested in aligning
. themselves with us in order to become part of this TAG grant, I would appreciate you
contacting me. You have until October 2nd to do so.
Again, this 16 million dollars that they have acquired to come in and start the cleanup
on the bum site will provide some jobs in this area. Colonel (LTQ Sowa has told me
that they will hire as locally as they can in order to help people participate out on the site
for the cleanup. This will be some money that will be put back into the economy in our
immediate area.
So, if you have any questions about the TAG grant - there probably will be some. Lisa
Price (EPA) will be working with me to help get funds for the technical assistance.
Hopefully, that will help in the future answer some question for the public.
Response:
The Army is interested in the free flow of information. Technical assistance grants is
a normal part of the process. The Army will continue to share information and solicit
your comments and inputs into the process as we continue.
24. Comment by unknown: .
How much will that cost the tax payers?
Response:
Typically the amount funded is a $50,000 grant.
25. Comment by Ruth Culver:
This grant will also last over the entire period of the Superfund. It is long term.
Response:
It is limited to a three year period. $50,000 over a three year period.
26. Comment by Rick Michaels:
I am with the Network Environmental Services from Baton Rouge, Louisiana. I have
been privileged enough to have doors opened to me out at the plant by the Longhorn staff
who have been kind enough to take us through step by step and show us the entire
process. I know that I am concerned about Caddo Lake and all of the ramifications that
any of these contaminants might have on the lake and the eco system itself, fish, water,
whatever. The main thing that impresses me though about this site is the way the Army
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is running it. I know the Army has a hand in creating this site but they are doing a great
job overseeing its-cleanup. I have seen a lot of these sites all over the country and I just
want to tell you my personal view is that you all are doing a great job with a terrible
situation that you have gotten in.
Response:
Thank you, we appreciate your comment This is a team effort and we look at it that
. way.
27. Comment by Tony Williams:
I am with the city of Marshall and am concerned with portions of Caddo Lake and
Bayous. For many months* the Longhom staff of the U.S. Army have been keeping us
informed on this project. I. have been invited to the meetings and I appreciate the flow
of information. I am proud that you all are so active in moving this thing forward.
Response:
(Statement, no response required)
28. Comment by Ardell Sweatman:
I would like to know a little about the emissions that are going to be released when you
all do all this. A little bit about the air pollution. Let's talk a little bit about it
Response:
The process is like a catalytic converter in your car that controls the emissions from the
car. What we will do is transfer the contaminants into a gas phase into the air in a
closed chamber. That air will go through a unit that will catalytically convert the
contaminants. They will be converted to carbon dioxide, hydrogen chloride, gas and
water, exactly like they are in the car, except for hydrogen chloride gas. The converted
material will then be mixed with a water solution that will capture the hydrogen chloride
gas. It will result in the removal of 99% (responder referencing treatabiUty study results)
of the contaminants of concern before they are emitted into the air. The resulting
solution, the acid solution will be used elsewhere in the treatment process so we have
almost a complete closed lid system. This process will be used in both of the
recommended soil and water treatment alternatives.
29. Comment by Carol Campbell:
Since this goes back so far, I really can't understand what I just found out about it last
week. Now, I have lived in Harrison County for many years and I am just wondering
what information has been put out to the public? The City Manager talks about the
information that he has been furnished. Has the public in general been getting, been
given information previously about what has been discovered, progress reports, and why
not, if they have not been furnished this information?
Response:
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We learn new things every day. However, as far as information to the public, we have
an administrative record at the Marshall Public Library that has been in place since 1991.
30. Comment by Carol Campbell:
Who knows about it? Do you advertise the fact that it is put there? I seemed to have
missed it, as have most of the people that I have talked to.
Response:
That 'is what this meeting is about If you have not seen it in the papers the last two
weeks, may be you are not reading many .papers. We are pretty visible. However, it
has taken some time to do studies. We had an indication that there were problems there.
We had to know the extent of the problems. We had to survey it We had to validate
the data. We validated the data to get the money to address the problem. So, it has
been a process. The TRC or the committee that meets and goes through the process, is
open to the public. We probably need to publish the date when we are having the next
TRC meeting. The TRC is a technical committee. We are going to be talking
engineering, about how to fix things. You are welcome to be there and welcome to ask
any question.
-\
31. Comment by Carol Campbell:
Well, I think it is an appropriate question since this was identified in the '70s, right?
Response:
We identified that there was a specific problem of contaminants out there.
32. Comment by Carol Campbell:
That's what I say. Okay, now, all during this period, they've had these studies going on?
Response:
That was to identify the extent of the contamination and to develop a solution for it.
33. Comment by Carol Campbell:
As far as I know though, the general public has not been informed about the progress.
that has been made during this particular period. In other words, we see the culmination
here tonight of what is taking place. But we have not been informed and kept informed.
I mean I can see the City Manager certainly needs to made aware of it because the City
of Marshall gets their water. We drink the water, though.
Response:
We hear your criticism, of course, always.
34. Comment by Carol Campbell:
The general public needs to be well informed. They need to be kept aware of the
contaminants, the problems, what's being done all along.
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Response:
That is a true statement That is what we arc attempting to do, it has hard for us to
address what it did not happen back in the 70s and 80s. We can tell you that we are
doing it now. We are trying to open this up and get the information flowing.
35. Comment by Dorothy Grant
When Longhom was put on the Superfund Site list, it came out in U.S. News and World
Report, Newsday and every other thing nationwide, USA Today, and indicated on the
map all the NPL sites. Those maps are available in the administrative record.
Response:
Thank you.
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The following include the comments and questions received in writing in two separate letters
during the public comments period and the U.S. Army response. A full account of the public
comments can be found in the site Administrative Record. The following comments were
submitted by the Uncertain Audubon Society
1. Comment:
What is "trichloroethylene?" Please explain its components in a way that untrained lay
. person can understand.
Response:
Trichloroethylene, also referred to as trichloroethene, or simply TCE is a clear and
colorless liquid. It has a chloroform-like odor. It is a man made non-flammable product
that has been used extensively as a degreasing agent and dry cleaning fluid throughout
the United States. In homes, this product may be an ingredient in typewriter correction
fluid, paint, carpet cleaning fluids, and varnishes.
2. Comment:
What is "methylene chloride?" Again, please explain so I can understand?
Response:
Methylene chloride is a clear and colorless liquid. It also gives off a chloroform-odor.
It is a non-flammable product that is used as a degreasing and cleaning agent. It is also
used in food processing (e.g. it is used in the coffee decafeination process).
3. Comment:
What other heavy metals have been detected at the burn site? (The handout mentioned
acetone, barium, chromium and lead.)
Response:
Other metals that have been detected in trace amounts include: arsenic, thallium, nickel,
cadmium, zinc, mercury, and selenium.
4. Comment:
How do these volatile compounds and metals affect the environment, for example how
do they contaminate water, soil, air?
Response:
These volatile compounds will dissipate rapidly if exposed to the air. Because methylene
chloride is water soluble, it will rapidly become diluted and the concentrations of the
chemical will decrease with mixing. Impacts on the soil are limited if the soil is exposed
to water because of the mobile nature of methylene chloride. Trichlorethylene has low
solubility, but is mobile in water. Metals are generally less mobile, and have very low
solubility, therefore this limits the ability to contaminate the environment.
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5. Comment:
What health hazards do the compounds and metals pose to humans? For example, if they
enter the water column and are ingested, is cancer .or some other life threatening disease
a likely result?
Response:
Trichlorethylene is a suspected carcinogen and is mildly toxic to humans by ingestion or
., inhalation. Effects of inhalation of trichlorethylene include headaches and drowsiness.
Methylene chloride is moderately toxic by ingestion. It is also an eye and moderate skin
irritant Metals such as nickel and barium can be dangerous in high concentrations if
ingested.
6. Comment:
Have these substances been found in the groundwater you have tested on site?
Response:
Yes, they have been detected, as discussed in the Proposal Plan, Section E of the Record
of Decision.
7. Comment:
If so, please provide me with a copy of the reports and data showing what's been found.
Response:
All the data is available in the Administrative Record, which is located at the Marshall
Public Library.
8. Comment:
Are the contaminants moving toward Caddo Lake through the soil or the groundwater?
Response:
Since the beginning of groundwater monitoring at the plant, the area of the contaminant
plume at the burning ground has increased in size such that its edge is closer to the lake.
The groundwater continues to be monitored. As part of the ongoing remedial
investigation/feasibility study, the best way to address the deeper groundwater
contamination will be determined. Soil contamination near the lake has not been
investigated due to the nature of the activities. Soil contamination is not expected near
Caddo Lake.
9. Comment:
If so, how soon are they likely to enter Caddo Lake? Have you already conducted tests
showing contaminants in the lake off site? If you have conducted off site tests, please
describe the location of each site and the results of the tests. Please provide a map of
the testing sites, the test data, and any report.
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Response:
The data to. answer these questions in detail continue to be collected in the ongoing
Remedial Investigation. Existing data does not allow a reliable prediction of when or
even if, significant concentrations of contaminants will enter the lake from the site.
Offsite tests have not been conducted. Present data do not indicate that contamination
has reached the facility boundary. However, we are aggressively pursuing the Early
Interim Remedial Actidn to mitigate this possibility of offsite migration of contaminants.
Additional investigation to support a risk assessment is being implemented. The risk
assessment will provide a prediction of what exposure is possible from the site.
Validated groundwater monitoring data from the Burning Ground No. 3 site is included
in the administrative record which is updated periodically as new data becomes available.
10. Comment:
What would the effect of methylene chloride, trichloroethylene, and heavy metals be
upon the water of Caddo lake, the inhabitants of the lake, such as fish, birds, turtles,
alligators, other vertebrates, and invertebrates?
Response:
The effects of any substances on Caddo Lake would depend on the concentration of those
substances, what substances were mixed in the water, other environmental stresses, and
the specific species involved. To attempt to determine any specific effects would be very
difficult to do at this time. Ecological data necessary to support a risk assessment is
currently being collected and evaluated. The risk assessment will address the potential
impact on the lake and its inhabitants.
11. Comment:
What are and have been the health hazards from the existence of such contaminants on
the site over many years, eg. is there a likelihood of increased cancer, leukemia, other
diseases in inhabitants living near LHAAP?
Response:
There is no indication of the release of contaminants offsite. Therefore, there is no
likelihood of any increase of risk to the nearby community. These issues will be
addressed in the risk assessment.
12. Comment:
What are the possible future health hazards to residents near LHAAP from the continued
existence of these compounds either without the proposed remedial action or with such
action?
Response:
There is no indication of the release of contaminants offsite. The site risk assessment
will address all possible future health hazards.
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13. Comment:
Does the proposed remedial action at the site pose any health problems to man or
environmental damage to the surrounding ecosystem?
Response:
The proposed interim remedial action will not pose any significant hazard to health or
the environment, and is designed to decrease any existing risk at the site. Short term
. exposure to construction personnel, during the interim action, will be minimized by the
use of proper controls and handling techniques, and by the implementation of a strict
health and safety program which will include continuous monitoring in the work zone and
the use of proper personal protection equipment
14. Comment:
What danger do these chemicals and heavy metals pose to human health if they enter the
water column, the aquifer underneath Longhom, and/or Caddo Lake?
Response:
As stated in the Proposed Plan, these contaminants are present in groundwater beneath
the Burning Ground No. 3 site. The investigation data is available in the Administrative
Record and was summarized in the Proposed Plan. Potential impacts will be evaluated
in the risk assessment once sufficient data has been collected. However, the
implementation of the interim remedial action will decrease or eliminate any potential
adverse impact to human health and the environment from the site while the ongoing
investigations are conducted.
15. Comment-
Why do you consider early interim remedial action to be necessary?
Response:
The high concentration of contaminants in groundwater at the site, and its close
proximity to Harrison Bayou and Caddo Lake creates conditions' conducive to the
potential introduction of contaminants to these aquatic systems via groundwater transport.
Consequences of this scenario could include contaminant exposure to human and
ecological receptors associated with these important aquatic resources. The magnitude
of future human and ecological exposure and associated risk estimates are dependent
upon further site characterization, and will be addressed in the site risk assessment.
Therefore, the U.S. Army is choosing to be proactive and initiate the Early Interim
Remedial Action to mitigate a threat that may occur in the future.
16. Comment:
What methods have you used to locate the identified contamination sites, for eg. aerial
photographs, "whistle-blowing," questionnaires, records?
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Response:
All sources of information were pursued including records, personnel interviews, aerial
photographs, and site inspections.
17. Comment:
What does the term "fence to fence" mean when applied to LHAAP as a Superfund site?
Response:
The term "fence to fence" means the entire LHAAP facility is listed on the National
Priorities lost rafher than specific sites. .
18. Comment:
Have you located all contamination sites at LHAAP?
Response:
Please refer to the responses of Public Meeting comments 2 through 5.
19. Comment:
Are there additional sites to be added to the listed Phase I and Phase n sites presented
at the September 15, 1994 hearing?
Response:
-For the record, please note that a public meeting was held on September 15, 1994 and
not a public hearing. Please refer to the responses of Public Meeting comments 4 and
5..
20. Comment:
How long do you estimate it will take you to locate all such sites at LHAAP?
Response:
Please refer to the responses of Public Meeting comments 4 and 5.
21. Comment:
Have you measured the depth of the deep groundwater through wells or other methods?
Response:
Groundwater at the burning ground and surrounding area has been measured in
monitoring wells. No other methods were used.
22. Comment:
If so, how deep is the groundwater at the Burn site?
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Response:
The water table at the burning ground has been measured between one foot and 23 feet
below existing ground surface.
23. Comment:
What deep ground water monitoring has been done at this site or elsewhere on LHAAP?
x
. Response:
The deepest groundwatef monitoring well inside the fence of the burning ground area
extends to about 70 feet below ground surface. The deepest groundwater monitoring
well outside the fence of the site extends to about 120 feet below ground surface. This
well is located outside the northeast comer of the burning ground.
24. Comment:
What are the results of such monitoring of the deep groundwater. i.e. what contaminants
are detected at deeper levels?
Response:
Traces of methylene chloride and trichloroethylene have been detected in the deepest
wells located in and around the site. Additional groundwater investigation is being
conducted in ongoing Phase n work. Detailed information is included in the
Administrative Record.
25. Comment:
If you have not begun such monitoring, when will you start to monitor the deep
groundwater?
Response:
The next scheduled phase of investigation will address this.
26. Comment:
Is LHAAP located over the primary aquifer or other substantial water supply to the East
Texas area?
Response:
Yes. LHAAP is situated on an outcrop of the Wilcox Group which has been identified
by the Texas Water Development Board as the basal unit of the regional Cypress aquifer,
also known as the Carrizo-Wilcox aquifer. This aquifer yields small fless than 50 gallons
per minute (gpm)) to moderate ( 50 to 500 gpm) quantities of fresh water to wells
throughout Harrison County. The Wilcox is also considered as the base of fresh water
in the area.
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27. Comment:
Describe what you've done to determine if the contamination is migrating toward Caddo
Lake?
Response:
Since the beginning of groundwater monitoring at the plant, the area of the contaminant
plume at the burning ground has increased in size such that its edge is closer to the lake.
The groundwater continues to be monitored. As part of the ongoing remedial
investigation/feasibility study, the best way to address the deeper groundwater
contamination will be determined. Soil contamination near the lake has not been
investigated due to the nature of the activities. Soil contamination is not expected near
Caddo Lake. This is the focus of the next remedial investigation phase at the Burning
Ground No. 3 site.
28. Comment: . .
Do you have a map of the area of the trichloroethylene plumes? you provided one in the
report for the methylene chloride plumes. Please furnish me a copy.
Response:
See Figure 8 in ROD
29. Comment: .
What are the identified sources of contamination to the soil and groundwater at Burning
Ground No. 3? What are the suspected other sources? Please described these in terms a
lay person can understand.
Response:
Burning Ground No. 3 has been in operation since 1955. The site has been used for the
treatment, storage, and disposal of pyrotechnic and combustible solvent wastes by open
burning, evaporation, and burial. Past waste management units have been identified as
the sources of contamination. These units include open burning pits where plant waste
were flash burned, an unlined evaporation pond (UEP) where liquid waste from the plant
was stored and allowed to evaporate, and waste, burial pits where solid waste such as
solvent soaked sawdust was disposed of and later covered with soil.
30. Comment:
How. long will it take you to conduct the formal Risk Assessment and what is the
anticipated cost?
Response:
The risk assessment is scheduled to be conducted between September 1995 and May
1996. Specific cost information is considered procurement sensitive and can not be
released until after the contract is awarded.
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31. Comment:
How will that assessment better inform the contaminated sites at LHAAP?
Response:
A risk assessment is a scientific procedure which uses facts and assumptions to estimate
the potential for adverse effect on human health and the environment from exposure to
site contaminants. The environmental or ecological risk assessment determines the
. present and future impacts on ecological receptors attributable to the site in its current
condition. Human health risks are determined by evaluating known chemical exposure
limits and actual concentrations at the site as identified by analysis of samples. The
actual contaminant concentrations are compared to exposure concentration known to have
an adverse impact In the risk assessment, carcinogenic (cancer causing) and non-
carcinogenic (other types of health effects, e.g. skin irritation) health risks are calculated.
Conservative assumptions that weigh in favor of protecting human health are made in
these calculations. This means if uncertainty exists on a particular effect, a worst case
scenario is generally assumed. The conclusions and recommendations of the risk
assessment will be used during the development of the final clean up action for the site.
The risk assessment will be included in the administrative record when completed and
approved by state and federal regulatory agencies.
32. Comment:
What information do you currently have about the migration of these substances into
shallow groundwater, deeper groundwater, and possible surface runoff?
Response:
Concerning the Groundwater please refer to responses for comments 8 and 28. No
surface runoff contamination has been detected at the site.
33. Comment:
Can you provide me a copy of the Administrative Record? Will there be a cost? If so,
how much will this record cost me? How long will it take you to provide this record to
me?
Response:
The Administrative Record currently consists of approximately 5,000 pages. This is
made up of technical reports, associated correspondence, and other relevant documents.
It is available at LHAAP and the Marshall Public Library. To obtain a copy directly
from the Government, you should follow the procedures under the Freedom of
Information Act.
34. Comment:
How long will the cleanup at the burn site take? what will it cost?
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Response:
The interim remedial action at the burning ground will take approximately five years and
cost 16 million dollars.
35. Comment:
How do you support the figure that you will be cleaning and treating 300 million gallons
of water (as stated at the hearing?) Please provide that support?
/
Response:
For the record, please note that a public meeting was held on September 15, 1994 and
not a public hearing. The pilot study, which was conducted on site in the Spring of 1994
to determine the most effective groundwater extraction technique, concluded that about
100 to 150 gallons per minute of shallow groundwater could be extracted from the site
for treatment. This will result in an approximate volume of 260 to 400 million gallon
of water over 5 years.
36. Comment:
Explain the process of air stripping proposed in Alternative 4 in terms a lay person can
understand?
Response:
Air stripping is a natural process to remove certain compounds, including chlorinated
solvents such as methylene chloride and trichloroethylene from water. Air is brought
into close contact with water containing the solvents. This is done through the use of a
tall, narrow pipe or "column" filled with plastic rings or "packing". The contaminated
water is pumped into the top of the column, and a simple device, called a "distributor"
distributes the incoming, contaminated water over the packing. The distributor works
like a shower head. The contaminated water trickles down the packing as a very thin
film, wetting each ring.
At the bottom of the column, clean, moist air is being blown in by a blower. This clean
air flows up through the packing rings. Due to the relatively low solubility of the
chlorinated solvents, the solvents leave or "strip" out of the water and into the air stream
passing across the water films. The water gets cleaner and cleaner as it approaches the
bottom of the column. The air stream gets more and more laden with solvents as it
moves up the column. The end result is clean water suitable for discharge and an air
stream that must be treated to remove the chlorinated solvents.
37. Comment:
Do you have a diagram of the air stripping process? Please include that in your response.
Response:
A diagram will be included in the Workplans for the Project. These will be incorporated
in the Administrative Record.
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38. Comment:
What is the compound you will use for the catalyst? what are its potential effects on the
environment and/or hazards to human health? how toxic is it?
Response:
The catalyst is a Platinum group catalyst on a ceramic carrier. The composition of the
catalyst is proprietary information held by the manufacturer (Johnson Matthey) and is not
specifically Platinum. The manner in which the material is handled, used, and disposed
of presents no known hazard to human health and the environment The materials are.
confined and in the form used are not considered toxic.
39. Comment-
How will you protect against groundwater runoff contamination when you are cleaning
the soil during this process?
Response:
A waste management and spill control plan that is approved by the EPA and TNRCC
will be implemented during the onsite remediation. Controls such as berms, dust
spraying, and silt fences will be used during implementation of the interim remedial
action.
40. Comment:
What methods will you use to contain any potential additional contamination to soil and
groundwater during the air stripping process?
Response:
Based on the design of the system, no such contamination will occur.
41. Comment:
What secondary containment system will you use around the converter?
Response:
There is no need for secondary containment. The materials being handled are in the gas
form in an enclosed chamber (flue gas off the desorber unit) and secondary containment
is not possible. The catalyst is in brick form and therefore contained within itself (no
liquid spills can be generated from the desorber or catalytic oxidizer units). The
scrubber section will have primary and secondary containment to handle 110% of the
held liquids.
42. Comment:
Have you run any safety tests for the site using this process? If so, what are the results
of such testing? Please provide the data and report for such testing. What is the
estimated cost of this process for the bum site?
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Response:
The proposed technologies for the interim remedial action are proven and widely used
throughout the United States. They have been shown to conform to Federal safety
standards. No specific testing other then setup, maintenance, and optimization is
required for these technologies. The total cost of soil treatment is estimated at 5 million
dollars.
43. Comment
Please provide the data showing that this method of treatment is more efficient that the
other proposed methods?
Response:
Please refer to the Proposed Plan document and the ROD for detail discussions on
different alternatives that were considered for the, site. For additional technical
information, refer to treatability study reports which are included in the Administrative
Record.
44. Comment:
Regarding Alternative 6, please describe that process in terms a lay person can
understand?
Response:
Onsite groundwater contains very low parts-per-million (ppm) traces of metals. The Safe
Drinking Water Act regulates the amounts of these metals that may be present in drinking
water. As a result, the common practice in preparing drinking water is'to make these
metals insoluble by adding chemicals to precipitate (to fall out of solution) the metals,
such as magnesium hydroxide (milk of magnesia) to collect the metals dissolved in the
water. The milk of magnesium will capture the incoming groundwater. The heavy
metals will stay with the magnesium all the way through solids dewatering and disposal.
45. Comment:
Please provide a diagram of the process with your response?
Response:
A diagram will be included in the workplans for the project. These will be incorporated
in the Administrative Record.
46. Comment:
What is the coagulant you propose using? What are its properties? Is it toxic? How might.
coagulant affect he environment or the health of humans?
Response:
We will remove suspended solids from groundwater using a process that is almost
identical to the one used for preparing drinking water. We expect to use trace (ppm)
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amount of coagulants commonly used to make, and approved for, drinking water. We
will also use ppm amounts of magnesium hydroxide (milk of magnesia) to remove
microscopic-diameter clay and silt particles (suspended solids) normally found in
groundwater.
The specific type will be determined just before the water treatment plant starts up to
ensure the best coagulant for the water at that time. We will also re-evaluate the specific
type throughout the year, since the groundwater can change with the seasons. We will
work'together with known manufacturers of coagulants, using coagulants approved for
drinking water preparation.
Site studies suggest about one pound of solids will enter the plant with each one thousand
gallons of water. These solids must be removed before pumping the water into the
stripping column to prevent plugging in the column. The coagulant and magnesia act
together to "capture" and bind very small particles that might otherwise plug up the
stripping column. These particles then settle out of the water in the "settler* as a 1 - 2%
slurry in water. .
This slurry, or "sludge", will be prepared for dewatering and disposal. Additional
thickening aids may be used to boost the solids concentration to 5 96 solids and 95%
water. These thickening aids will also be approved for potable water use and will be
sued in very small amounts. The thicker sludge will then be air stripped in covered
cone-bottom tanks. That air, containing chlorinated solvents, will be treated along with
the air from the stripper. The clean sludge may be further thickened, then gently
pumped onto the nearby sand drying bed located under a pavilion to keep out rain.
There, the sludge will dry out forming a small amount of "cake" that contains up to 40%
solids and at least 60% water. All water that drains from the sludge will be pumped
back to water treatment.
47. Comment:
How is the process controlled from a containment point of view, so as to avoid
contamination of the soil and groundwater?
Response:
The entire process is conducted in vessels that are protected against corrosion. The
entire process area is contained inside a concrete bermed area. All water captured inside
the process area will be treated.
48. Comment:
How much precipitation do you believe will be generated from this process? What will
be the contents of that precipitation? Is the precipitation toxic? What are its potential
effects on the environment and the health of humans?
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Response:
The products of the process are clean water and dried cake for landfill at an approved
site. We expect to discharge up to 300 gallons per minute of clean water. The solids
cake, consisting of cleaned silts, clays, magnesium and small amount of polymer could
total 500 pound per day of dry matter or 800 pounds per day of cake. The volume is
very small, less than 1.5 cubic yards per day. Reasonable care will be taken to minimize
the amount of silt and clay that is pumped from the groundwater recovery wells. The
actual pounds of solids may be well below the estimates listed here. The cake is not
expected to exhibit hazardous characteristics as defined by the Resource Conservation and
Recovery Act (40 CFR §261).
49. Comment:
What is the proposed cost of this process? How did you reach that number?
Response:
The total cost of this process is estimated to be $2,080,300. This includes the amount
of funding required to purchase and install the equipment used in the process, and to
operate and maintain the system.
50. Comment:
Where do you intend to take the precipitant off-site or on-site? What will you iio to store
the precipitant? Please describe the storage proposal in detail.
Response:
The cake will be managed in accordance with Texas and Federal requirements. They
will be tested to determine if the cakes are hazardous or non-hazardous. The cake will
be hauled to an approved landfill in Department of Transportation-approved containers
such as drums or bins. Disposal will also comply with Texas and Federal requirements.
51. Comment:
Regarding Alternative 8, please describe the process in terms a lay-person can
understand.
Response:
Simply speaking the soil is placed into a rotating pipe. Hot air is passed over the soil
to heat the soil and release the contaminants from the soil (leaving the soil clean). The
hot air then passes through a set of filters (to remove any dust that was caught up in the
hot air stream). After passing through the filters the gas is passed to the secondary
heating chamber where hot air is used to heat the gas to the catalyst activation
temperature (the catalyst, just like the catalyst in the car, must be an a minimum
temperature to work properly). The gas then passes through the catalyst and are
completely oxidized to hydrochloric acid, sometimes referred to as Muriatic Acid [the
acid used in swimming pool pH control], C02, and water. Plants use CC^, and expire
O2. Humans produce CO2
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during respiration. This oxidation takes place at relatively low temperatures
(about 800 °F). The gas is then passed through a cooling chamber (called a
Quench) and then through a Scrubber. The scrubber uses water and sodium
hydroxide to scrub the acid from the gas and in so doing produces table salt
(NaCl). The salt is dissolved in the water used to scrub the acid and is processed
through the water treatment plant that is to be located on the site. The gases
leave the system with CQj, water and minor amounts of other gases (like
nitrogen from the air used to -heat the soil).
52. Comment:
Please provide a diagram of the process with your response.
Response:
A diagram will be included in the workplans for the project These will be incorporated
in the Administrative Record.
S3. Comment:
How do you treat the off-gases and what will these gases consist of? Are they toxic?
What hazards do they pose to humans and the environment?
Response:
Please note answer to written comment number 51. The off gases from the treatment
system are not toxic and will pose no appreciable risk to human health or the
environment.
54. Comment:
Where on the site will you place the treated soil? How clean from contamination will
that soil be after treatment?
Response:
The excavated soil and source material would be treated to reduce the VOCs
contamination. The data collected during the treatability studies did not demonstrate that
the full scale operation of any of the appropriate treatment technologies, with the possible
exception of the incineration, can attain the Land Disposal Restrictions regarding
treatment standards imposed under RCRA (40 CFR 268). The treatment technologies
will comply with the Land Disposal Restrictions through a Treatability Variance (40 CFR
268.44) for the wastes. The treatment level range that will be established through the
Treatability Variance for the treatment technologies is a 90 to 99.9 percent reduction in
the concentration of the contaminants upon the completion of the treatment process. The
treated soil will be used as backfill material for the trench areas. The treated source (the
higher contaminated material) will be placed under a landfill cap on the LHAAP
installation.
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55. Comment:
What tests do you have to support your contention about the efficiency of this alternative
and the ability of Alternative 8 to clean the soil? Please provide a copy of the data
supporting your position. What will be the cost of this process and what is your support
for that number?
Response:
The Low Temperature Thermal Desorber has been operated on several sites containing
contaminants similar to the contaminants identified at the Longhorn site. The soil being
remediated passed all applicable standards for land disposal for each of the sites. In
addition significant design testing has been conducted by the supplier of the catalyst
system. The supplier guarantees the system (at design conditions) to remove 99% of all
designed for chlorinated contaminants. Please refer to Table 1 in ROD for cost
information.
56. Comment:
How will you dispose of the contaminants removed and where on-site will you dispose
of them? Please describe the storage system you propose using for these contaminants.
Response:
The soil contaminants removed from the soil will be converted to hydrochloric acid,
sometimes referred to as Muriatic Acid [the acid used in swimming pool pH control],
CO2 (the gas produced by plants during respiration), and water. The acid will be
absorbed by water in a quench and scrubber and the C02 and water will be vented to the
atmosphere (see response to comment number 51).
57. Comment:
What secondary containment system will you use to avoid runoff of contaminants into
groundwater or soil during this remediation process?
Response:
Refer to response for comment number 39.
58. Comment:
Many times, in discussing this subject, you have used the terms "probable", "possible",
and "probable cause". Please define those terms.
Response:
The terms are used as in normal english usage indicating an effect, event, or cause that
may or may not be actual (i.e. has a degree of uncertainty).
59. Comment:
What is the "worst case" scenario to human health and the environment of the proposed
Alternatives 4, 6, and 8?
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Response:
The worst case is to leave the-groundwater contamination as it now is.
60. Comment:
Are you soliciting bids from the private sector for use of any part of LHAAP?
Response:
We appreciate the comments/questions provided (above) and understand your concern.
However, these issues are not related to the proposed interim action at Burning Ground
No. 3. Accordingly, responses are beyond the scope of this forum which is dedicated
to the proposed efforts at Burning Ground No.3, and will be deferred for present
61. Comment:
What is the process by which you are soliciting such bids? When was this process
started?
Response:
See response to written comment number 60.
62. Comment:
Who is authorized to contract with the private sector for lease or sale of any portion of
LHAAP , the government, Thiokol, others?
Response:
See response to written comment number 60.
63. Comment:
Please explain how the Army or others can actively solicit bids if all the contaminated
sites have not been determined, if the LHAAP has been classified in its entirety as a
Superfund site, and if remedial action has not been commenced?
Response:
See response to written comment number 60.
64. Comment:
How would leasing or sale to private parties comply with the directive that activities at
LHAAP are appropriate and protect the health and welfare of the public and the
environment?
Response:
See response to written comment number 60.
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65. " Comment:
Is there anything in Thiokol's contract with the Army that provides for their sharing in
the costs of clean-up? Can you provide me with a copy of that contract?
Response:
See response to written comment number 60.
66. Comment:
Would you please send me a copy of the Responsiveness Summary? The request form
is attached.
i
Response:
Yes a copy of the Responsiveness Summary will be sent to the address provided.
67. Comment:
Will there be any contamination in air emissions from either Alternative 4, 6, and 8?
If so, please describe these contaminants and how you intend to capture and/or treat
them? What health hazards do such contaminants pose to humans and the environment? .
Response:
Refer to the responses to written comments 51 and 56.
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The following comments were received from Mr. Mark Chance:
1. Comment:
Will the risk assessment be completed and results be available before actual response
action is taken?
Response:
No. This is an Early Interim remedial Action, which by definition is done prior to
completion of the risk assessment
2. Comment:
Who will actually implement the response actions- Army or EPA personnel, a third party
contractor, or a combination?
Response:
Response actions will be implemented by the Army and its contractors as needed.
However, EPA and TNRCC will continue to be involved in the planning and decision
making process.
3. Comment:
How often will progress reviews be made available to the public during actual
implementation of the response actions?
Response:
Updates on the remedial action will be provided at the quarterly Technical Review
Committee meetings which are open to the public.
4. Comment:
Are there any plans to make the Administrative Record available to the public in an
electronic format?
Response:
Such plans do not exist at the present time.
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