PB99-964008
EPA541-R99-026
1999
EPA Superfund
Record of Decision:
Stauffer Chemical Company
(LeMoyne Plant) Site OU 2
Axis, AL
3/18/1999
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5/-*, •*. » \ r-) i
"J u u 'J 1
STAUFFER CHEMICAL CO. (LEMOYNE PLANT) SITE
OPERABLE UNIT TWO
AXIS, MOBILE COUNTY, ALABAMA
PREPARED BY
U. S. ENVIRONMENTAL PROTECTION AGENCY
REGION 4
ATLANTA, GEORGIA
RECORD OF DECISION
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
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TABLE OF CONTENTS
1.0 SITE LOCATION AND DESCRIPTION , !
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 1
4.0 SCOPE AND ROLE OF OPERABLE UNIT ; 6
5-0 SUMMARY OF SITE CHARACTERISTICS 7
5.1 GEOLOGY/SOILS 7
5.2 SURFACE WATER \\[\[ g
5.3 HYDROGEOLQGY \ 8
5.4 NATURE AND EXTENT OF CONTAMINATION'!" '..'"".".".'','.', '." ' g
5-5 CURRENT AND POTENTIAL FUTURE SITE AND RESOURCE TTSF.S ... 13
6.1 CONTAMINANTS OF CONQERN '','.'.'.'.','.'.'. 14
6.2 EXPOSURE ASSESSMENT 14
6.3 TOXICITY ASSESSMENT '.'.'.'.'.'.'.'.'.'.'.'.'.". 19
6.4 RISK CHARACTERIZATION .'.'.'.'.'.'.'.'.'.'. 21
6.5 ECOLOGICAL RISK '.'.'.':'.'.'.'.'.'.'.'.'.'.'.'.'.'.'.'. 24
6.6 REMEDIATION OBJECTIVE? ' '.'.'.]'.';'.'.'.'. ...... ....... 25
7-0 DESCRIPTION OF ALTERNATIVES 28
7.1 ALTERNATIVE NO. 0 - NO ACTION 28
7.2 ALTERNATIVE NO. 1 - INSTITUTIONAL CONTROLS 28
7-3 ALTERNATIVE NO 2 - MULTI-LAYER CAP 29
7-4 ALTERNATIVE NO. 3 - EXCAVATION AND OFFSITE DISPOSAL .... 29
7-5 ALTERNATIVE NO. 4 - EXCAVATION AND EX-SITU QNSITE
BIOREMEDIATIQN 29
7.6 ALTERNATIVE NO. 5 - EXCAVATION AND EX-SITU BIOREMEblATION/
IN-SITU SOIL FLUSHING 29
7-7 ALTERNATIVE NO. 6 - EXCAVATION AND OFFSITE DISPQSAI7
IN-SITU FLUSHING 30
7.8 ALTERNATIVE NO. 7 - IN-SITU SOIL FLUSHING 30
7.9 ALTERNATIVE NO. 8 - ASPHALT CAP 30
8.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES 31
8.1 OVERALL PROTECTION OF HUMAN HEALTH AND THE
ENVIRONMENT 32
8.2 COMPLIANCE WITH ARARS ^33
, 8.3 LONG-TERM EFFECTIVENESS AND PERMANENCE 34
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8-4 REDUCTION OF TOXICITY MOBILITY OR VOLUME THROTirrH tifc
TREATMENT 34 ^
8-5 SHORT-TERM EFFECTIVFNPS^ 34
8.6 IMPLEMENTABILITY "" ,,
8.7 COST •". *
8.8 STATE ACCEPTANCE .'.'.' ~
8.9 COMMUNITY ACCEPTANPF :...'.'!.'!.'.'.'.'.'].'.'.'.'!!." .36
9-0 SUMMARY OF SELECTED RFMFTW ... .
9.1 SOIL REMgDY '
9.2 PERFORMANCE STANnARns FOR SOIL ''''''' 35
10-0 STATUTORY DETERMINATION
iai PROTECTION OF HUMAN HEALTH AND THEEN™QNVTKNT ' 40
10-2 ATTAINMENT OF THE APPT.TrABLE OR RKT JWA^FFTvK
APPROPRIATE REQUIREMENTS f ARARs) 40
U-0 DOCUMENTATION OF STfiNIFICANT CTTAKORS 42
TABLES
TABLE 5-1 - SUMMARY OF MAXIMUM CARBON TETRACHLORIDE POND SOIL
BORING DATA lft
TABLE5-2 - SUMMARY OF MAXIMUM CARBON blSULFffiE POND sb£ BORING '
. 11
"' MAXIMUM FORMER HALBY AREA'BORING DATA ...u
TABLE 6-1 - SUMMARY OF CHEMICALS OF POTENTIAL CONCERN ]6
TABLE 6-2 - EXPOSURE CONCENTRATIONS AT HALBY POND AREA 17
TABLE 6-3 - EXPOSURE CONCENTRATION AT CARBON DISULFIDE POND AND OIL
CARBON TETRACHLORIDE WWT POND , 8
TABLE 6-4 - EXPOSURE CONCENTRATION AT OLD FIREWATER POND AND
UNNAMED TRIBUTARY 19
TABLE 6-5 - CANCER SLOPE FACTORS FOR CHEMICALS OF POTENTIAL CONCERNED
TABLE 6-6 - REFERENCE DOSES FOR CHEMICALS OF POTENTIAL CONCERN 22
TABLE 6-7 - TOTAL RISKS ASSOCIATED WITH DERMAL CONTACT INHALATION
AND INGESTION ' 23
TABLE 6-8 - COMPARISON OF OBSERVED CONCENTRATIONS TO WATER QUALITY CRITERIA
TABLE 6-9 - PERFORMANCE STANDARDS FOR SUBSURFACE SOELS ............26
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TABLE 6-10 - STATUS OF ELIMINATED POTENTIAL SOURCE AREAS 27
TABLE 9-1 - SUBSURFACE SOIL PERFORMANCE STANDARDS 37
TABLE 9-2 - SUMMARY OF SELECTED REMEDY COSTS 39
TABLE 10-1 APPLICABLE OR RELEVANT AND APPROPRIATE REGULATIONS .... 43
FIGURES
Figure 1 - Area Map 2
Figure 2 - Site Map 3
APPENDICES
Appendix 1 - Responsiveness Summary
Appendix 2 - State Concurrence Letter
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DECLARATION
of the
RECORD OF DECISION
OPERABLE UNIT TWO
SITE NAME AND LOCATION
Stauffer Chemical Co.(LeMoyne Plant) Site, Operable Unit Two
Axis, Mobile County, Alabama
STATEMENT OF BASIS AND PURPOSE
This decision document (Record of Decision), presents the selected Remedial Action for Operable
Unit Two for the Stauffer Chemical Co.(LeMoyne Plant) Site ("Stauffer LeMoyne Site" or
"Site"), Operable Unit Two, Axis, Mobile County, Alabama, developed in accordance with the
Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA), as
amended, 42 U.S.C. Section 9601 el Sfifl., and to the extent practicable, the National Contingency
Plan (NCP) 40 CFR Part 300. This decision is based on the administrative record for the Stauffer
site.
The State of Alabama, as represented by the Alabama Department of Environmental Management
(ADEM), has been the support agency during the Remedial Investigation and Feasibility Study
process for the Stauffer LeMoyne Site. In accordance with 40 CFR 300.430, as the support
agency, ADEM has provided input during this process. The State of Alabama, as represented by
ADEM, has concurred with the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from the Stauffer LeMoyne Site, if not
addressed by implementing the response action selected in this ROD, may present an imminent
and substantial endangerment to public health, welfare or the environment.
DESCRIPTION OF SELECTED REMEDY
This operable unit is the second of three for the Site. This alternative requires the design and
implementation of response measures which will protect human health and the environment. EPA
signed a ROD for the first operable unit on September 27,1989. The first operable unit
addressed the groundwater contamination at this Site and the Stauffer Chemical Co. (Cold Creek
Plant) Site ("Stauffer Cold Creek Site"). The remedy for the first operable unit is ongoing. The
second operable unit addresses the source contamination in the subsurface soil. The ROD for the
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second operable unit will be the last ROD for the Stauffer LeMoyne Site. EPA signed a ROD for
the third operable unit on September 17,1993. The third operable unit, which addresses
contamination in the Cold Creek Swamp, is in the remedial design phase.
The major components of the selected remedy for operable unit two are:
• Institutional controls to restrict construction on the former Halby area until the subsurface soil
performance standards are met and to restrict the Stauffer LeMoyne Site from converting to
residential use until such time as EPA determines through a risk assessment that the Site is
available for unrestricted use,
• Construction of a soil flushing system in the former Halby area to accelerate the migration of
contaminants from the subsurface soil into the groundwater where contaminants will be
captured and treated by the existing OU1 groundwater remedy,
• Monitoring of subsurface soil for cyanide and thiocyanate in the former Halby area on an
annual basis to ensure that contaminants are moving into the groundwater in a controlled
manner where they will be captured and treated by the OU1 groundwater remedy, and
• Periodic reporting of annual monitoring results to EPA.
Because a risk assessment for a future residential scenario was not performed for OU2 of the Site,
institutional controls restricting the Site from use as residential property must remain in place until.
a human health risk assessment is conducted which demonstrates to EPA that the Site does not
pose any unacceptable risks to future residents. Restriction of construction on the former Halby
area is necessary to allow soil flushing to occur in this area. Monitoring of groundwater
concentrations will continue under the OU1 remedy. The cost of the OU2 remedy is estimated to
be $501,000.
The selected remedy will address the principal threat waste of thiocyanate in the subsurface soil.
Thiocyanate is highly mobile to the groundwater and will continue to move into the groundwater
in an uncontrolled manner, if the remedy is not implemented. The selected remedy also addresses
the low-level threat of cyanide in the subsurface soil. This remedy will accelerate and monitor the
movement of contaminants from the subsurface soil into the groundwater, and will be able to
control the movement, if necessary.
This remedy is preferred over the other alternatives considered due to its cost effectiveness and
short term effectiveness. This remedy will protect human health and the environment and will
meet all applicable or relevant and appropriate regulations, while minimizing the expenditure of
resources.
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STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the environment, complies with federal and
state requirements that are legally applicable or relevant and appropriate, and is cost-effective.
This remedy satisfies the preference for treatment that reduces toxicity, mobility, or volume as a
principal element. Treatment is provided by flushing contamination from the subsurface soil.
Further treatment is provided by the OU1 groundwater remedy. Finally, h is determined that this
remedy utilizes a permanent solution and alternative treatment technology to the maximum extent
practicable.
ROD DATA CERTIFICATION CHECKLIST
The following information is included in the Decision Summary section of this Record of
Decision. Additional information can be found in the Administrative Record file for this site.
• Chemicals of concern (COCs) and their respective concentrations
• Baseline risk represented by the COCs
• Cleanup levels established for COCs and the basis for the levels
• Current and future land and groundwater use assumptions use in the baseline risk assessment
and ROD
• Land and groundwater use that will be available at the site as a result of the Selected Remedy
• Estimated capital, operation and maintenance (O&M), and total present worth costs; discount
rate; and the number of years over which the remedy cost estimates are projected
• Decisive factors that led to selecting the remedy
This remedy is based on risk assessments for industrial use scenarios. Contamination may be
present which would restrict the use of this property for residential use. Because this remedy may
result in hazardous substances remaining on-site above levels that allow for unlimited use and
unrestricted exposure, a review will be conducted within five years after initiation of remedial
action to ensure that the remedy continues to provide adequate protection of human health and
the environment.
RICHARD D. GREEN, DIRECTOR DATE
WASTE MANAGEMENT DIVISION
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Decision Summary
Record of Decision
Operable Unit Two
Staufler Chemical Co. (LeMoyne Plant) Superfund Site
Operable Unit Two
Axis, Mobile County, Alabama
1.0 SITE LOCATION AND DESCRIPTION
The Stauffer Chemical Co. (LeMoyne Plant) Superfund Site (hereinafter, "Stauffer LeMoyne" or
"the She") is located approximately 20 miles north of Mobile Alabama on U.S. Highway 43. The
CERCLIS identification number for the Site is ALD008161176. For an area location map and
general Site map, see Figures 1 and 2, respectively. The Site encompasses approximately 730
acres. The Site is an industrial facility bounded by the Stauffer Chemical Co. (Cold Creek Plant)
site ("Stauffer Cold Creek) on the north, Courtaulds North America, another chemical company
on the south, the Mobile River on the east, and Highway 43 on the west. The area is
predominantly industrial, with a few small rural residential communities within a few miles of the
site. The site is currently owned and operated by Akzo Nobel Chemicals, Inc. (Akzo) which
manufactures carbon disulfide, sulfuric acid, and a proprietary sulfur compound at the facility.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
The Stauffer LeMoyne site was previously owned by Stauffer Chemical Company ("Stauffer"),
which began operations in 1953. In 1987, the facility was purchased by Akzo Chemie America,
Inc., now called Akzo Nobel Chemicals, Inc. Wastewaters from the Stauffer LeMoyne processes
were held in ponds, some of which discharged to the Cold Creek Swamp. All of these ponds
except for one were clay-lined and were closed under the direction of AWIC. Several membrane-
lined ponds, which are currently active, were installed during the 1970's to replace those
mentioned above. One of these is regulated by a Resource Conservation and Recovery Act
(RCRA) permit.
From 1965 to 1979, a small portion of land on the western end of the LeMoyne site was leased by
Stauffer to the Halby Chemical Company (HCC), which manufactured dye chemicals. This area is
located adjacent to the Norfolk-Southern Railroad line and is approximately 700 feet north of the
main entrance to the Stauffer LeMoyne she. Witco, Inc. purchased the HCC facility (the "former
Halby area") in 1974, and continued to operate the plant until 1979. The plant used the following
raw materials: carbon disulfide, ammonia, caustic soda, ethyiene oxide, methyl acrylate, hydrogen
sulfide, and para-toluenesulfonic acid. The plant produced ammonium thiocyanate, sodium
thiocyanate, ammonium sulfide, sodium sulfur hydrate, thiodiglycolate, and methyl
mercaptopropionic acid as products and by-products.
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Figure 1 - Area Map
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0 U 1 0
Figure 2 - Site Map
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SVUMU LEGEND
t - COLD CREEK NORTH LANDFILL 10
2-COLD CREEKLECREEKWASTE 11
WATER TREATMENT POND
3 - COLD CREEK OLD NEUTRALIZATION POND «
4- COLO CREEK SOUTH LANDFILL
.6 - FORMER HAL»Y POND AREA 13
6 • NORTH CHECK POND 14
7 • OLD CHLORINE PLANT WASTE
WATER TREATMENT POND «
* - UNNAMED TRIIUTARY 10 •
i • OLD BRINEMUD POND 17 •
IS-
OLD FIREWATER POND
CARBON DISULFIDE WASTE WATH*
TREATMENT PONO
OLD CARtON TETRACHLORIOE PLANT
WASTE WATER TREATMENT POND
LEMOYNE LECREEKTftEATMENT PONO
NEW CARBON TETRACHLORIOE PLANT
WASTE WATER TREATMENT PONJD
LEMOYNE LANDFILL
LEMOYNE LANOFIU SULFUR SPILL AREA
LEMOYNE SWAMP SULFUR SPILL AREA
LEMOYNE SWAMP
I
I
UMidCVVBt
aau M rvr
Figure 2 - Site Map (continued)
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59 0012
A waste pond ("the Halby Pond") was located in the southwest portion of the former Halby area,
adjacent to the Norfolk Southern Railroad. Waste products and effluents, including thiocyanates,
were reportedly discharged to this pond. The pond was approximately 5,000 square feet in area
and may have been clay-lined. In 1979, the facility closed the pond by filling it with soil and
possibly other debris from demolition work in the former Halby area. The pond does not have an
impermeable cap.
Disposal practices led to soil and groundwater contamination which was discovered by Stauffer
and the Alabama Department of Environmental Management (ADEM) in the early 1970's when
contaminants were detected in both on-site and off-site wells. Several improvements and waste-
handling modifications were made including the construction of lined wastewater ponds and the
closure of some of the old unlined ponds. In 1973, Stauffer installed twenty-one groundwater
monitoring wells. By 1977, the water quality had deteriorated substantially and seven observation
wells were place at the southern property line of the Stauffer LeMoyne she. Using the results
from a hydrogeological investigation performed by Stauffer, three interceptor wells accompanied
by an air stripper were installed on the Stauffer LeMoyne site in late 1980. The system was
approved by the Alabama Water Improvement Commission (AWIC) which is now ADEM.
The Alabama Department of Public Health (ADPH) conducted an assessment of the site in 1982.
At the advice of ADPH, additional monitoring wells were installed around the LeMoyne Landfill
which is located on the eastern side of the Stauffer LeMoyne site. Data from these wells formed
the basis for placing the Site on the National Priorities List in September 1983.
Previous investigations at the site include a remedial investigation for Operable Unit One (OU1),
which focused on groundwater. This investigation was started in 1985 and completed in 1988. A
RCRA facility assessment was conducted in 1992. In addition, an evaluation of selected source
areas (contaminated ponds, soils, and sediments) from the Stauffer LeMoyne site and Stauffer
Cold Creek site was conducted to determine if evidence existed to suggest that the source areas
were releasing contaminants to the groundwater.
In 1984 EPA Region 4 sent a general notice letter to Stauffer Chemical Company notifying them
of potential liability for contamination at the Stauffer Chemical Co. Site (which originally included
both the Stauffer LeMoyne and the Stauffer Cold Creek sites). Stauffer agreed to conduct a
remedial investigation/feasibility study (RI/FS) under a consent agreement with EPA and the
current owners completed the work. The present owner, Akzo, agreed to prepare a RI/FS for
OU2. Akzo completed the RI/FS for OU2 under EPA's direction. This study included
evaluations of possible risk and measures to reduce risk.
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
As part of the earlier work for the Stauffer LeMoyne and Stauffer Cold Creek sites, a community
relations plan was completed in September 1985. In May 1986, EPA distributed a fact sheet
describing the site history and findings of investigations conducted at the sites. A fact sheet
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announcing EPA's proposed plan for Operable Unit One for both sites was issued in July 1989. A uB
public comment period with a public meeting was opened to solicit comments on the proposed
remedial action at both sites. EPA signed a Record of Decision for OU1 of the Stauffer LeMoyne
and Stauffer Cold Creek sites on September 17,1989.
The public comment period on the proposed plan for this ROD (operable unit two) was July 31,
1998 through September 30,1998. A public meeting was not requested by the public. The
administrative record was available to the public at both the information repository maintained at
the Satsuma Branch Library in Satsuma, Alabama, and at the EPA Region IV Library at 61
Forsyth Street in Atlanta, Georgia. The notice of availability of these documents was published in
the Mobile Register on July 31,1998. The notice of the extension to the public comments period
was published on September 3,1998 in the Mobile Register Responses to the significant
comments received during the public comment period are included in the Responsiveness
Summary which is part of this ROD (Appendix A).
This decision document presents the selected remedial action for operable unit two of the Stauffer
LeMoyne site, chosen in accordance with CERCLA, as amended, and the NCP. The decision for
this Site is based on the administrative record. The requirements under Section 117 of
CERCLA/S ARA for public and state participation have been met.
4.0 SCOPE AND ROLE OF OPERABLE UNIT
EPA has organized the work at this Superfund Site into three operable units (OUs). The Site was
divided into three operable units after EPA determined that additional investigations and
treatability studies were necessary before EPA could make decisions on the source areas and
swamp. These units are:
• OU 1: Contaminated groundwater underlying the Site which is being addressed by an ongoing
operations and maintenance of the pump and treat remedy. EPA signed a ROD for OU1 on
September 17, 1989. The purpose of operable unit one was to initiate groundwater restoration
and reduce contaminant migration into the groundwater. Future ingestion of groundwater
extracted from the aquifer poses a potential risk to human health because EPA's acceptable
risk range is exceeded and concentrations of contaminants are greater than the maximum
contaminant levels for drinking water (as specified in the Safe Drinking Water Act).
• OU 2: Source areas on the Site. This OU originally included 18 separate source areas - six
closed wastewater ponds, two inactive ponds, two active ponds, three surface water bodies,
two spill areas, and three landfills - for the Stauffer Cold Creek and Stauffer LeMoyne
facilities. Fourteen of these source areas are included in the Stauffer LeMoyne site. The
purpose of this operable unit is to remove sources of contamination which can result in further
groundwater contamination. This operable unit is addressing the principal threat of
thiocyanate which is migrating from subsurface soil into the groundwater.
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• OU3: Cold Creek Swamp. Activities at the Stauffer LeMoyne She have contributed to
contamination in the Cold Creek Swamp. EPA signed a ROD for OU3 on September 27,
1993. The purpose of this operable unit is to remove contamination from the swamp so that it
no longer poses a threat to human health or the environment. This operable unit is in the
remedial design phase and is addressing the principal threat of surface water and sediment
contamination which poses a current and potential threat to human health and the environment.
5.0 SUMMARY OF SITE CHARACTERISTICS
The conceptual site model for Operable Unit Two involves wastewater ponds, a landfill, and
drums and tanks as the primary sources. Infiltration/percolation from the ponds and landfill and
spills from the drums and tanks served as the primary release mechanism into the soil. Secondary
release mechanisms from the soil include dust and/or volatile emissions which could be carried by
wind to human and ecological receptors, infiltration/percolation into the groundwater which could
carry contaminants to human receptors, and storm water runoff which could carry contaminants
by surface water or sediments to human or ecological receptors.
5.1 GEOLOGY/SOILS
The geology beneath the Stauffer LeMoyne Site can be characterized as marine alluvial deltaic
sediments. Two shallow clayey-sand units extend to depths of 120 feet along the western area of
the site and thin slightly to bottom depths of 80 feet along the eastern river shoreline. This
surficial clayey-sand formation comprises the shallow aquifer and resides atop a dense-stiff bluish
green clay formation which forms an aquaclude with a slight dip toward the west and ranges in
thickness from 40 to 60 feet. Shallow sediments are comprised of fine to medium grained, clean
quartz sands, reddish-brown to grayish tan hi color. These sands are interbedded with grey-clay
strata, yellowish-brown to grey silty-clay lenses and quartz-gravel beds forming the upper
unconsolidated sand unit of the shallow aquifer. This shallow zone exhibits low to moderate
permeabilities caused by interbedding and discontinuous clayey strata across the Site. The upper
sand unit extends to depths of 50 to 60 feet along the western area of the Site, thinning to depths
of 30 to 50 feet along the eastern shoreline area. Lower sands of the shallow aquifer are cleaner,
coarser, and more angular with depth even occurring as 1/4 inch quartz gravel layers within this
lower zone. These coarse, clean sands comprise the water source as they exhibit moderate to
relatively high permeabilities and transmissivities. A relatively shallow clay layer in the western
portion of the Site may effectively separate the shallow aquifer into two water-bearing zones and
produce semi-confined conditions in the aquifer in certain areas. The Site is underlain by a basal
Miocene-age blue-green clay that acts as a confining layer below the shallow aquifer.
Two main U.S. Department of Agriculture soil types dominate the She. The first is the Izagora-
Bethera/Annemaine group which is common in coastal drainage areas, exhibit good drainage and
support woodland vegetation dominating the western-central portion of the Site. The other is the
Dorovan-Levy soil type which is common to coastal flooded areas, exhibiting hydric or saturated
conditions most of the year. This soil type covers most of the Mobile River shoreline area. The
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Izagora soil type is characterized as a loamy-marine sediment with a high available water capacity
and is usually well to moderately well drained, with poor fertility due to low organic content The
sod type is typically acidic and allows for a deep root zone. The Halby Pond area is located atop
the Izagora soils onsite. The Bethera Group is characterized by its location in shallow
depressions or drainage areas with poor drainage. Typically, the soil group consists of silly-clay
loam which is frequently wet from constant contact with surface or groundwater The Bethera
soil group exhibits a high available water capacity, is low in natural fertility, has low to moderate
organic content, and is usually acidic. These soUs are common along the Carbon Tetrachloride/
Carbon Disulfide ponds and extend northward in the Unnamed Tributary which runs from south
side of the Site to the Cold Creek Swamp located on the Stauffer Cold Creek site The
Annemaine Group is characterized by its location in saturated or damp areas (year-round) The
soil group is composed of silts and clays which are mostly wet or damp. The Annemaine group
exhibits a high availability of water capacity, frequently contains organics with moderate to low
lertility, and is usually acidic. The Dorovan-Levy association is limited in extent to the Mobile
Rive shoreline. These soils are characterized as very poorly drained, organic-muck sediments
which can support vegetation and coastal forests. Typically, these soils area very fertile always
moist, and provide wildlife habitat for coastal foraging fauna.
5.2 SURFACE WATER
Surface drainage from the western portion of the Stauffer LeMoyne site is toward an unnamed
stream (the Unnamed Tributary) which flows northward toward the Cold Creek Swamp The
eastern portion of the Stauffer LeMoyne site is adjacent to and drains toward the Mobile River
Flooding potential at the site is considered to be minimal
5.3 HYDROGEOLOfiY
Prior to industry utilizing the groundwater, the direction of groundwater flow was eastward
toward the Mobile River and the depth to groundwater ranged from 0 to 20 feet below ground
surface Pumping of wells for industrial water supply on the adjacent Courtaulds property has
resuhed in a lowering of the water table to between 25 and 75 feet below ground surface
Furthermore, direction of groundwater flow has been changed to southwest on the western
portion of the Site and to the southeast on the eastern portion. Most of the industries and local
communities in the area obtain water from the surficial aquifer.
5-4 NATURE AND EXTENT OF rONTAMINATTOK
EPA identified 14 potential source areas at the Stauffer LeMoyne site Five are closed
wastewater treatment (WWT) ponds:
• Old Carbon Disulfide WWT Pond
• Old Chlorine Plant WWT Pond
• Chlorine Plant North Check Pond
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• Old Brine Mud Pond, and
• Halby Treatment Pond.
Two units are inactive ponds:
• Old Carbon Tetrachloride Plant WWT Pond, and
• New Carbon Tetrachloride Plant WWT Pond.
One is an active pond:
• LeMoyne LeCreek WWT Pond.
Three units are associated with surface water bodies. One is man-made:
• the Old Firewater Pond,
and two are natural:
the Unnamed Tributary, and
LeMoyne Swamp.
Two units are associated with sulfur spills:
• LeMoyne Swamp Sulfur Spill Area, and
• LeMoyne Landfill Sulfur Spill Area.
One unit is a landfill:
• LeMoyne Landfill.
During the first remedial investigation in 1988, sampling was conducted around the ponds and
landfills at the Site. Soil borings were made around the ponds and samples were analyzed for
contaminants of potential concern. Analyses of composite soil samples associated with the Old
Carbon Tetrachloride WWT Pond and the Old Carbon Disulfide WWT Pond found low levels of
carbon tetrachloride and carbon disulfide. Soil samples from the Halby Pond detected levels of
copper and zinc above background. Cyanide and thiocyanate were also found in Halby Pond
samples (Table 5-1).
A background surface water sample was collected from the Unnamed Tributary near the southern
edge of the StaufFer LeMoyne site. The only contaminants detected were mercury and zinc. Four
sediment samples and one surface water sample were collected from the LeMoyne Swamp.
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OU17
Concentrations of mercury, arsenic, beryllium, chromium, lead, and nickel were detected at or
near background levels. Concentrations of copper and zinc were elevated in comparison to
background levels.
TABLE 5-1 - SUMMARY OF MAXIMUM CARBON TETRACHLORIDE POND SOIL
BORING DATA
BORING DEPTH
(FEET)
Surface (0 - 0.5)
7
14
21
28
35
42
CARBON BISULFIDE
(UG/KG)
74
7
ND
ND
ND
ND
ND
CARBON TETRACHLORIDE
(UG/KG)
80
46
ND
89
5
9
34
ND-Not detected
Additional remedial investigation activities were conducted at the Old Carbon Disulfide WWT
Pond, the Old Carbon Tetrachloride WWT Pond, the Halby Pond, the Old Firewater Pond, and
the Unnamed Tributary in 1993 and at the LeMoyne Swamp in 1994. Additional investigations
were not conducted at eight of the potential source areas, because contamination at these areas
were addressed by existing presumptive remedies or the areas were currently regulated under
other EPA authorities. The source areas which were eliminated from further investigation were
the Old Chlorine Plant WWT Pond, the Chlorine Plant North Check Pond, the Old Brine Mud
Pond, the New Tetrachloride Plant WWT Pond, the LeMoyne LeCreek WWT Pond, the
LeMoyne Swamp Sulfur Spill Area, the LeMoyne Landfill Sulfur Spill Area, and the LeMoyne
Landfill. The field activities at the remaining six source areas included soil borings and sampling,
surface water and sediment sampling, and fish tissue sampling. Four soil borings were drilled at
both the Old Carbon Disulfide WWT Pond and the Old Carbon Tetrachloride WWT Pond.
Nineteen soil borings were drilled at the Halby Pond. Sediment samples were collected from the
Unnamed Tributary, the Old Firewater Pond, and the LeMoyne Swamp. Surface water samples
were taken in the same locations at the sediment samples and also in the Old Carbon
Tetrachloride WWT Pond.
The ecological field investigation conducted in April 1994 involved the LeMoyne Swamp, the
Unnamed Tributary and the Old Firewater Pond. Fish samples were collected from the LeMoyne
Swamp. A benthic community analysis and fish community survey were conducted in the
10
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5 9
0018
Unnamed Tributary and the Old Firewater Pond. Physicochemical parameters (water
temperature, dissolved oxygen, pH, and conductivity) were also analyzed in these areas.
TABLE 5-2 - SUMMARY OF MAXIMUM CARBON BISULFIDE FOND SOIL
BORING DATA
DEPTH (FEET)
Surface (0 - 0.5)
7
14
21
28
35
42
CARBON BISULFIDE
(UG/KG)
ND
ND
88
12
4
i
ND
840
CARBON TETRACHLORIDE
(UG/KG)
4
ND
800E
51
31
18
9700
ND - Not detected
E - Exceeded calibration range of GC/MS
Sampling results from the soil borings at the Old Carbon Tetrachloride WWT Pond and the Old
Carbon Disulfide WWT Pond, are presented in Tables 5-1 and 5-2.
Four sets of data have been collected in the former Halby area. In the 1986 site investigation,
three soil borings indicated the presence of elevated levels of thiocyanates at depths of up to 40
feet. The remedial investigation conducted in 1993 consisted of three angled borings, two eight-
foot borings, and 14 30-foot borings, with analysis for carbon disulfide, thiocyanates, and cyanide.
In 1995 four additional soil samples for thiocyanate analysis were collected at a depth of 30 feet at
locations approximating the locations of four earlier borings. Additional data was collected in
1998 to further characterize the site. Table 5-3 summarized the data from the former Halby area.
Some studies indicate that cyanide results obtained from soil analyses in the former Halby area
may be false positives caused by the nature of the analytical method utilized. Nevertheless,
because this premise has not has not been adequately demonstrated, cyanide remains as a
contaminant of concern at the Site. Future analysis using improved analytical methods may
demonstrate that cyanide is not present in the soil.
11
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S 9
OC'i9
TABLE 5-3 - SUMMARY OF MAXIMUM FORMER HALBY AREA BORING DATA
BORING
DEPTH (FEET)
Surface (0-0.5)
5-10 Feet
15-21 Feet
25-30 Feet
35-40 Feet
CARBON BISULFIDE
iUG/KG) *
ND
25
280
270
NS
THIOCYANATE
(MG/KG) **
11A
2000
9000
90,000***
300
CYANIDE
(MG/KG) **
3.57A
12.3J
5.15J
18.61
13.3J
ND-Not detected
NS-Not sampled
J - Estimated value
A - Average value
* -1993 data
**-1998 data
*** - Result may be a sampling anomaly. Next highest value is 5000 mg/kg.
Surface water sampling results for the Old Carbon Tetrachloride WWT Pond were non-detectable
for carbon tetrachloride and carbon disulfide. Surface water and sediment sampling results for the
Old Firewater Pond and the Unnamed Tributary are presented in Tables 5-4 and 5-5.
TABLE 5-4 - SUMMARY OF MAXIMUM SURFACE WATER AND SEDIMENT
DATA AT THE OLD FIREWATER POND
CONTAMINANT
Carbon disulfide
Carbon tetrachloride
Chromium
Iron
Mercury
Zinc
Cyanide
Thiocyanate
SURFACE WATER (UG/L)
14
ND
ND
680
ND
64.4
ND
ND
SEDIMENT (UG/KG)
ND
ND
260
38,500
10.6*
8,790
0.835
ND
ND - Not detected
* - Duplicate analysis not within control limits
12
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5 9
0020
Mercury contamination in the LeMoyne Swamp sediment ranged from below 0.22 mg/kg to 1.7
mg/kg. Contamination in a nearby reference area ranged from 0.22 mg/kg to 0.28 mg/kg.
Mercury contamination in fish tissue from LeMoyne Swamp ranged from below 0.08 mg/kg to
0.84 mg/kg. Mercury contamination in fish from the reference area ranged from below 0.08
mg/kg to 0.78 mg/kg.
5.5 CURRENT AND POTENTIAL FUTURE SITE AND RESOURCE USES
Current on-site land use is industrial. The Stauflfer LeMoyne Site is owned and operated by Akzo
Nobel Chemicals, Inc. (Akzo) which manufactures carbon disulfide, sulfiiric acid, and a
proprietary sulfur compound there. The Site is currently surrounded by additional industrial
facilities and the Mobile River. The anticipated future land use for this area is industrial.
The groundwater beneath the Site is classified as Class n groundwater, which is a potential source
of drinking water (Guidelines for ground-water classification under the EPA ground-water
protection strategy, Final Draft, November 1986, Office of Ground-water Protection, Office of
Water, U.S.E.P.A.). This groundwater is currently used for industrial purposes, but not for
drinking water sources. The USGS report entitled Geohydrogeology and Susceptibility of Major
Aquifers to Surface Contamination in Alabama; Area 13 (1988) designates the area around the
TABLE 5-5 - SUMMARY OF MAXIMUM SURFACE WATER AND SEDIMENT
DATA AT THE UNNAMED TRIBUTARY
CONTAMINANT
Carbon disulfide
Carbon tetrachloride
Chromium
Iron
Mercury
Zinc
Cyanide
Thiocyanate
SURFACE WATER (UG/L)
28
ND
3.2B
969
ND
46.4
ND
ND
SEDIMENT (UG/KG)
ND
ND
72. IN
17,800*
3.5N*
325
0.835
29.6
ND - Not detected
B - Reported value is less than the contract Required Detection Limit, but greater than the
Instrument Detection Limit
* - Duplicate analysis not within control limits
13
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5 9 0021
Site as a recharge area for a major aquifer which is highly susceptible to surface contamination.
The groundwater beneath the She is not expected to be used as a drinking water source in the
next 30 years, since alternative water supplies from other aquifers are available. However, these
alternative water supplies utilize groundwater near the Site as sources of drinking water.
6.0 SUMMARY OF OPERABLE UNIT TWO RISKS
CERCLA directs EPA to conduct a baseline risk assessment to determine whether a Superfund
Site poses a current or potential threat to human health and the environment in the absence of any
remedial action. The baseline risk assessment provides the basis for determining whether or not
remedial action is necessary and the justification for performing remedial action. Based upon this
analysis EPA determined that the subsurface soil poses a risk to potential users of groundwater.
The migration of subsurface contaminants into the groundwater would pose a risk for potential
adult and child residential users of the groundwater. Direct exposure to soil does not pose a
significant risk to on-site workers. Actual or threatened releases of hazardous substances from
this Site, if not addressed by implementing the response action selected in this ROD, may present
a current or potential threat to public health, welfare, or the environment.
6.1 CONTAMINANTS OF CONCERN
The majority of the wastes and residues generated by production operations at the facility have
been managed, treated, and disposed of onsite throughout the Site's history. The chemicals
measured in the various environmental media during the RI were evaluated for inclusion as
chemicals of potential concern in the risk assessment by application of screening criteria.
Cyanide, thiocyanate, carbon tetrachloride, carbon disulfide, chromium, mercury, and zinc were
identified as chemicals of potential concern (COPCs) for OU2 of the Site. These compounds
were found in surficial and subsurface soils, sediment, and surface water. Table 6-1 presents the
COPCs and their concentration ranges.
6.2 EXPOSURE ASSESSMENT
Whether a chemical is actually a concern to human health and the environment depends upon the
likelihood of exposure, i.e. whether the exposure pathway is currently complete or could be
complete in the future. A complete exposure pathway (a sequence of events leading to contact
with a chemical) is defined by the following four elements:
• A source and mechanism of release from the source,
• Atransport medium (e.g., surface water, groundwater, air) and mechanisms of migration
through the medium,
• The presence or potential presence of a receptor at the exposure point, and
14
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b 9 0022
A route of exposure (ingestion, inhalation, dermal adsorption).
If all four elements are present, the pathway is considered complete.
An evaluation was undertaken of all potential exposure pathways which could connect chemical
sources in source areas (soil and subsurface soil) at the Site with potential receptors. All possible
pathways were first hypothesized and evaluated for completeness using EPA's criteria. The
current pathways represent exposure pathways which could exist under current Site conditions
while the future pathways represent exposure pathways which could exist, in the future, if the
current exposure conditions change (such as by installing drinking water wells). For both current
and future exposure scenarios, EPA assumed the Site would remain in industrial use. Therefore,
residential scenarios were not examined. Exposure by each of these pathways was mathematically
modeled using generally conservative assumptions.
The current pathways are:
• incidental ingestion of surface water, sediment, or soil by maintenance workers,
• potential dermal exposure by on-site maintenance workers to on-site surface soils,
sediment, or surface water,
• potential inhalation exposure by on-she maintenance workers to dust, and
• potential inhalation of volatile emissions by on-site maintenance workers.
The future pathways are:
potential oral exposure by on-site construction workers to on-site surface soils,
• potential dermal exposure by on-site construction workers to on-site surface soils,
• potential inhalation exposure by on-site construction workers to dust,
• potential inhalation of volatile emissions by on-site construction workers, and
• potential ingestion of groundwater from a future drinking water well.
EPA assumed for this assessment that there would be no significant human exposure at the
LeMoyne Swamp, since the area is not subject to construction or maintenance activities and is not
easily accessible to trespassers from the Mobile River.
15
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TABLE 6-1 - SUMMARY OF CHEMICALS OF POTENTIAL CONCERN
Media
Halby Area Soil
Old Carbon Tetrachloride and Carbon
Dinilfide WWT Ponds Soil
Old Firewater Pond Sediment
Unnamed Tributary Sediment
LeMoyne Swamp Sediment
Old Firewater Pond Surfrce Water
Unnamed Tributary Surface Water
Chemical
Carbon Disulfide
Cyanide
Thiocyanate
Carbon Disulfide
Carbon Tetrachloride
Zinc
Chromium
Mercury
Cyanide
Zinc
Chromium
Mercury
Mercury
Carbon Disulfide
Carbon Disulfide
Zinc
Concentration Detected
Minimum
4
0.118
3.43
4
1
1,400
171
3.9*
0.835
14.1
5.6N
0.6N*
0.35
11
12
16.8
Maximum
280
59.6
90,000**
840
9700
8,790
260
10.6*
0.835
325
72. IN
3.5N*
1.7
14
28
46.4
Units of
Measure
ppb
pom
ppm
ppb
ppb
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppb
ppb
PI*
Frequency of Detection
10/78
32/78
52/78
10/52
26/52
3/3
3/3
3/3
1/3
5/5
5/5
5/5
in
3/3
3/5
5/5
cn
ppm - parts per million
ppb-parts per billion
* - Duplicate analysis not within control limits
** • Result may be a sampling anomaly. Next highest value is 9,000.
16
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5 9
0024
The exposure point concentrations for each of the chemicals of concern and the exposure
assumptions for each pathway were used to estimate the chronic daily intakes for the potentially
complete pathways, with the exception of the groundwater pathway. The chronic daily intakes
were then used in conjunction with cancer potency factors and noncarcinogenic reference doses to
evaluate risk.
Exposure concentrations are provided in Tables 6-2, 6-3, and 6-4. All exposure concentrations
are based on the 95% upper confidence limit on the arithmetic mean concentration for each
chemical. Air concentrations were calculated using models from EPA's SuperfundExposure
Assessment Manual (USEPA, 1988).
Exposure assumptions for an on-site maintenance worker are as follows:
• Ingestion rate is 50 ml/day for water and 50 mg/day for sediment and soil.
Exposure frequency is 24 days/year; exposure duration is 25 years.
• Skin surface area exposed is 3,600 cm2; inhalation rate is 0.833 m3/hour; body weight is 70
kg-
TABLE 6-2 - EXPOSURE CONCENTRATIONS AT HALB Y POND AREA
Maintenance Worker
Chemical
Carbon disulfide
Cyanide
Thiocyanate
Soil Concentration,
Surface Only
(mgftg)
1.96xlO'J
2.75 x lO'1
1.23xlO+1
Air(VOC)
Concentration from
Soil (mg/m3)
5.03 x 10-5
Dust Concentration
from Soil, Traffic
Only (mg/m3)
8.65 xlO"9
1.21x10-*
5.41 x 10'5
Construction Workers
Chemical
Carbon disulfide
Cyanide
Thiocyanate
Soil Concentration,
Surface Only
(mgfcg)
1.67 xl(T3
3.07 x 10°
3.46 x 10+2
Air(VOC)
Concentration from
Soil (mg/m3)
4.28 x 10-*
Dust Concentration
from Soil, Traffic
Only (mg/mj)
7.25 x 10*1
1.42xlO's
i.eoxio-3
17
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5 9
0025
• Averaging time is 25 years for noncarcinogens and 70 years for carcinogens.
• Soil dermal adherence factor is 1 mg/cm1; dermal absorption factor is 0.25 (unitless) for
VOCs and 0.01 for inorganics.
Exposure assumptions for an on-site construction worker are as follows:
• Exposure frequency is 40 days/year; exposure duration is 1 year.
• Skin surface area exposed is 3,600 cm2; inhalation rate is 1.25 mVhour; body weight is 70
kg.
• Averaging time is 1 year for noncarcinogens and 70 years for carcinogens.
• Soil dermal adherence factor is 1 mg/cm2; dermal adsorption factor is 0.25 for VOCs and
0.01 for inorganics.
• Ingestion rate is 50 mg/day; exposure time is 8 hours/day.
TABLE 6-3 - EXPOSURE CONCENTRATION AT CARBON BISULFIDE POND AND
OIL CARBON TETRACHLORIDE WWT POND
Maintenance Workers
Chemical
Carbon Disulfide
Carbon Tetrachloride
Soil Concentration,
Surface Only
(mg/kg)
2.67 xlO'2
2.81 x lO'2
Air(VOC)
Concentration from
Soil (mg/m3)
6.83 x W4
3.28 x 10-4
Dust Concentration
from Soil, Traffic
Only (mg/m3)
l.lSxlO'7
1.24xlO'7
Construction Workers
Chemical
Carbon Disulfide
Carbon Tetrachloride
Soil Concentration,
Surface Only
(mg/kg)
5.23 x 10'2
5.59 xlO'1
Air(VOC)
Concentration from
Soil (mg/m3)
1. 34xlO'3
6.51 x 103
Dust Concentration
from Soil, Traffic
Only (mg/m9)
2.43 x lO'7
2.59 x 10-6
VOC - Volatile organic chemicals
18
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5 9
6.3 TOXICITY ASSESSMENT
Toxicity assessment is a two-step process whereby the potential hazards associated with route-
specific exposure to a given chemical are (1) identified by reviewing relevant human and animal
studies; and (2) quantified through analysis of dose-response relationships. EPA has conducted
numerous toxicity assessments that have undergone extensive review within the scientific
community. EPA toxicity assessments and the resultant toxicity values were used in the baseline
risk assessment to determine both carcinogenic and non-carcinogenic risks associated with each
chemical of concern and route of exposure. EPA toxicity values that are used in this assessment
include:
cancer slope factors (CSFs) for carcinogenic effects, and
reference dose values (RfDs) for non-carcinogenic effects.
TABLE 6-4 - EXPOSURE CONCENTRATION AT OLD FIREWATER POND AND
UNNAMED TRIBUTARY
Maintenance Workers
Chemical
Carbon Disulfide
Carbon Tetrachloride
Chromium
Cyanide
Mercury
Thiocyanate
Zinc
Surface Water
Concentration
(mg/L)
1.76xlO"2
3.65 x 10-4
3.27 xlO'3
5.00 x 10"3
9.54 x 10"5
2.50 xlO'2
5.41 x 10'2
Sediment
Concentration
(mg/kg) .
4.30 xlO"3
1.33 x lO'3
1.54 xlO*2
3.49 xlO'1
6.05 x 10°
1.29x10*'
3.49 xlO*3
Air Concentration
from Surface Water
(mg/m3)
2.49 x 10'1
3.66 x lO'3
-
-
-
-
—
Cancer slope factors are route-specific values derived only for compounds that have been shown
to cause an increased incidence of tumors in either human or animal studies. The slope factor is
an upper bound estimate of the probability of a response per unit intake of a chemical over a
lifetime and is usually determined by high-dose to low-dose extrapolation from human or animal
studies. When an animal study is used, the final slope factor has been adjusted to account for
extrapolation of animal data to humans. If the studies used to derive the slope factor were
conducted for less than the life span of the test organism, the final slope factor has been adjusted
19
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5-9 0027
to reflect risk associated with lifetime exposure. Chromium which is present in the Old Firewater
Pond and Unnamed Tributary is considered to be carcinogenic if it is in the hexavalent form and it
exposure occurs by the inhalation route. Since the only inhalation pathway at the Old Firewater
Pond and Unnamed Tributary is inhalation of volatile compounds, chromium is not an issue as a
carcinogen at this Site. Carbon tetrachloride is the only carcinogenic chemical of potential
concern (COPC) at this Site. Carbon tetrachloride is classified by EPA as a probable human
carcinogen (EPA weight of evidence Class B2). Table 6-5 presents cancer slope factors for
carbon tetrachloride. The oral slope factor and inhalation unit risk number were obtained from
EPA's Integrated Risk Information System (IRIS). An inhalation slope factor was derived from
the unit risk using standards assumptions. The dermal slope factor was established by adjustment
of the oral slope factor by the default oral absorption factors.
TABLE 6-5 - CANCER SLOPE FACTORS FOR CHEMICALS OF POTENTIAL
CONCERN
Chemical
Carbon Tetrachloride
Oral Slope Factor
(mg/kg-day)'1
0.13
Dermal Slope Factor
(mg/kg-day)'1
0.16
Inhalation Slope
Factor (mg/kg-day)*1
0.053
Reference doses (RfDs) have been developed by EPA for indicating the potential for adverse
health effects from exposure to chemicals exhibiting noncarcinogemc effects. Reference doses are
ideally based on studies where either animal or human populations were exposed to a given
compound by a given route of exposure for the major portion of the life span (referred to as a
chronic study). The RfD is derived by determining dose-specific effect levels from all the
available quantitative studies, and applying uncertainty factors to the most appropriate effect level
to determine a RfD for humans. The RfD represents a threshold for toxicity. RfDs are derived
such that human lifetime exposure to a given chemical via a given route at a dose at or below the
RfD should not result in adverse health effects, even for the most sensitive members of the
population. Table 6-6 presents the reference doses for the chemicals of potential concern.
Chronic oral toxicity RfDs were obtained from IRIS for all COPCs except thiocyanate. No
toxicity data for thiocyanate is available in either IRIS or the Health Effects Assessment Summary
Tables (HEAST). The EPA Health Risk Superfund Technical Support Center calculated a
provisional RfD for thiocyanate, which was used in the risk assessment for this Site.
Subchronic RfDs can be used when the exposure duration is less than seven years. However, to
be conservative in this risk assessment, the chronic oral RfDs were used for the subchronic
exposures for carbon disulfide, chromium, cyanide, mercury, thiocyanate, and zinc. Carbon
tetrachloride has an established subchronic toxicity value.
Dermal toxicity values were calculated from the chronic and subchronic oral RfDs by applying
chemical-specific oral adsorption factors. EPA default adsorption values for volatiles (80%),
semi-volatiles (50%), and inorganics (20%) were used to adjust the oral toxicity values.
20
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5 9 0028
Inhalation reference concentrations are not available, except for mercury in IRIS and carbon
disulfide in HEAST. These values were converted to RfDs for the risk assessment. For the other
COPCs, the oral RfDs were substituted as inhalation RfDs to evaluate inhalation exposure.
6.4 RISK CHARACTERIZATION
Human health risks are characterized for potential carcinogenic and non-carcinogenic effects by
combining exposure and toxicity information. For carcinogens, risks area generally expressed as
the incremental probability of an individual's developing cancer over a lifetime as a result of
exposure to the carcinogen. Excess lifetime cancer risk is calculated from the following equation:
Risk = CDIxSF
where: risk = a unitless probability (e.g., 10'5) of an individual's developing cancer
GDI = chronic daily intake averaged over 70 years (mg/kg-day)
SF « slope factor, expressed as (mg/kg-day)"1
These risks are probabilities that are generally expressed in scientific notation (e.g., 10"*). For
example, an excess lifetime cancer risk of IxlO"6 indicates that an individual experiencing the
reasonable maximum exposure estimate has a 1 in 1,000,000 chance of developing cancer as a
result of site-related exposure. This is referred to as an "excess lifetime cancer risk" because it
would be in addition to the risks of cancer individuals fact from other causes such as smoking or
exposure to too much sun. The chance of an individual's developing cancer from all other causes.
has been estimated to be as high as one in three. EPA's generally acceptable risk range for site-
related exposures is 10"4 to 10*.
EPA considers individual excess cancer risks in the range of 10"4 to 10"* as protective; however
the 10"* risk level is generally used as the point of departure for setting cleanup levels at
Superfund sites. The point of departure risk level of 10"* expresses EPA's preference for remedial
actions that result in risks at the more protective end of the risk range. The risks calculated for
human direct contact at this she are below the 10"6 risk level (Table 6-7).
Potential concern for noncarcinogenic effects of a single contaminant in a single medium is
expressed as the hazard quotient (HQ) (or the ratio of the estimated intake derived from the
contaminant concentration in a given medium to the contaminant's reference dose). A HQ which
exceeds one (1) indicates that the daily intake from a scenario exceeds the chemical's reference
dose. By adding the HQs for all contaminants within a medium or across all media to which a
given population may reasonably be exposed, the Hazard Index (HI) can be generated. The HI
provides a useful reference point for gauging the potential significance of multiple contaminant
exposures within a single medium or across media. An HI which exceeds unity indicates that
there may be a concern for potential health effects resulting from the cumulative exposure to
multiple contaminants within a single medium or across media.
21
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TABLE 6-6 - REFERENCE DOSES FOR CHEMICALS OF POTENTIAL CONCERN
Chemical
Carbon Disulfide
Carbon Tetrachloride
Chromium
Cyanide
Mercury
Thiocyanate
Zinc
Chronic
Oral RfD
(mg/kg-day)
0.1
0.0007
1
0.02
0.0003
0.1
0.3
Chronic
Dermal RfD
(mg/kg-day)
0.08
0.00056
0.2
0.004
0.00006
0.05
0.06
Chronic
Inhalation RfD
(mg/kg-day)
0.0029
0.0007
1
0.02
0.0003
0.1
0.3
Subchronic
Oral RfD
(mg/kg-day)
0.1
0.007
1
0.02
0.0003
0.1
0.3
Subchronic
Dermal RfD
(mg/kg-day)
0.08
0.0056
0.2
0.004
0.00006
0.05
0.06
Subchronic
Inhalation RfD
(mg/kg-day)
0.0029
0.007
1
0.02
0.0003
0.1
0.3
en
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0 C 30
TABLE 6-7
TOTAL RISKS ASSOCIATED WITH DERMAL CONTACT, INHALATION AND
DIGESTION
AREA
Halby Area
Halby Area
Carbon Disulfide and
Old Carbon
Tetrachloride WWT
Ponds
Carbon Disulfide and
Old Carbon
Tetrachloride WWT
Ponds
Old Firewater Pond
and Unnamed
Tributary
Total Current Risk
Total Future Risk
SCENARIO
Maintenance Worker
Construction Worker
Maintenance Worker
Construction Worker
Maintenance Worker
Maintenance Worker
Construction Worker
CANCER RISK
NA
NA
4.0x10"*
7.9x10-*
NA
4.0xlO-*
7.9x10-*
NON-CANCER RISK
(HI)
2.0x10*
6.8xlO-3
4.4xlO'3
2.2xlO'2
S.SxlO*1
S.SxlO'1
2.9xlO-J
NA - Cancer risks are not applicable to this scenario.
The HQ is calculated as follows:
Non-cancer HQ = CDI/RfD
where:
CDI = Chronic daily intake
RfD = Reference dose
CDI and RfD are expressed in the same units and represent the same exposure period (i.e.,
chronic, subchronic, or short-term).
For direct exposure to soil, surface water, and sediment, the results of the risk assessment
indicated that all cumulative non-carcinogenic hazards to human health were several orders of
23
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b 9 0031
magnitude below the threshold of concern. Table 6-7 presents the results of the risk assessment fflp
for direct exposure to soils, sediment and water at the Site.
Utilizing the SUMMERS model for soil contaminants leaching to groundwater, it was determined
that soils in the Halby area could continue to leach thiocyanate and cyanide to the underlying
groundwater aquifer at levels that would result in the exceedance of groundwater standards
established by EPA. The SUMMERS model calculations are included in the RI/FS documents
located in the Administrative Record. Although there are uncertainties in the calculation of soil
remedial goals for groundwater protection, the SUMMERS model analysis is a conservative
approach that does not underestimate the impacts of soil contamination on groundwater quality.
Carbon disulfide was not detected in groundwater. Therefore, thiocyanate and cyanide were
retained as chemicals of concern. The results of the model are supported by levels of
contaminants of concern found in monitoring wells in the vicinity of the Halby area. Thiocyanate
concentrations in groundwater currently exceed calculated acceptable groundwater levels (based
on potential drinking water source). Cyanide concentrations in groundwater currently exceed
EPA's Safe Drinking Water Act Maximum Contaminant Levels (MCLs). The soils pose an
unacceptable risk to future users of groundwater as a drinking water source.
Throughout the risk assessment process, uncertainties and variabilities associated with evaluation
of chemical toxicity and potential exposures exist. For example uncertainties arise in derivation of
toxicity values for reference doses (RfDs) and carcinogenic slope factors (CSFs), estimation of
exposure point concentrations, fate and transport modeling, exposure assumptions and ecological
toxicity data. Because of the conservative nature of the risk assessment process, risks estimated
in this assessment are likely to be overestimates of the true risks associated with current or
potential exposure at OU 2 of the Stauffer LeMoyne Site.
6.5 ECOLOGICAL RISK
The LeMoyne Swamp offers habitat for aquatic, aviary, and terrestrial wildlife. Although mercury
was detected in the sediments at elevated levels, the mercury fish tissue concentrations are at
background levels. Mercury contamination in the LeMoyne Swamp sediment ranged from below
0.22 mg/kg to 1.7 mg/kg. Contamination in a nearby reference area ranged from 0.22 mg/kg to
0.28 mg/kg. Mercury contamination in fish tissue from LeMoyne Swamp ranged from below 0.08
mg/kg to 0.84 mg/kg. Mercury contamination in fish from the reference area ranged from below
0.08 mg/kg to 0.78 mg/kg. Foraging activities, breeding, and resident habitats occur elsewhere,
indicating short term and low intensity use and exposure at the LeMoyne Swamp. The
contamination at this area poses a limited risk to ecological receptors.
The source areas, except for the LeMoyne Swamp, offer a limited and poor quality habitat for
area wildlife. The areas are located a significant distance from any areas capable of supporting
substantial numbers of animals. The wooded areas west of the Halby Area, west of the
headwaters of the tributary, and at the junction of the tributary and Cold Creek Swamp have the
greatest potential to support wildlife. There is no indication that any animals in the wooded areas
24
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0032
frequently enter these source areas. The mowed and disturbed areas have limited habitat for
foraging or movement by most species, although occasional foraging is expected. Access to these
source areas is limited due to traffic and physical barriers, such as fencing. The COPCs in these
areas pose a limited risk to ecological receptors (Table 6-8).
TABLE 6-8
COMPARISON OF OBSERVED CONCENTRATIONS TO WATER QUALITY CRITERIA
Chemical
Observed Concentration (ug/L)
Range
Mean
Criteria1
Unnamed Tributary
Carbon disulfide
Chromium
Iron
Zinc
3-14
1.6-3
391-969
16.8 - 46.4
Old Firewater Pond
Carbon disulfide
Iron
Zinc
11-14
664 - 680
51.6-64.4
7
2.4
582.8
35.1
2,100 -162.0001
1 1 (Chromium VI)2
2 10 (Chromium III)2
l.OOO2
HO2
12.3
667
59.3
2.100-162.0001
l.OOO2
no2
1AQUIRE database. Acute and chronic range for potentially resident species including
mosquitofish (Gambusia qffinis), orange spotted sunfish (Leponis hvmilis), water flea (Daphnia
magna\ and green algae (CMorella pyrenoidosa).
2 Based on U. S. EPA freshwater quality criteria.
6.6 REMEDIATION OBJECTIVES
The remedial action objective (RAO) for OU2 of the Site is to prevent contamination from
migrating to groundwater. This RAO is based on the potential beneficial groundwater use as a
drinking water supply. The selected remedy will reduce concentrations of contaminants in
subsurface soil to levels which will not result in exceedances of groundwater standards or action
levels established by EPA for OU1 of the Site.
The establishment of health-based cleanup goals serves as an important means of guiding remedial
activities. A health-based approach is warranted when cleanup standards promulgated by state or
25
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federal agencies are not available for contaminants in soil, as well as for certain groundwater HB
contaminants. The approach to developing health-based goals is derived from the risk assessment ^^
process. The risk assessment is essentially a process by which the magnitude of potential cancer
risks and other health effects at a site can be evaluated quantitatively. A cleanup goal is
established by back-calculating a health protective contaminant concentration, given a target
cancer risk or hazard index which is deemed acceptable and realistic. The concept of the cleanup
goal inherently incorporates the concept of exposure reduction which allows remedial alternatives
to be flexible.
For thiocyanate a groundwater performance standard of 3.5 mg/1 was used to calculate the
protective subsurface performance standard. The thiocyanate performance standard was
calculated using the reference dose established by EPA. Assumptions used in calculating the
groundwater performance standard are body weight of 70 kg, water ingestion of 2 liters per day,
and a provisional reference dose (RfD) of 0.1 mg/kg-day. The SUMMERS groundwater model
was used to backcalculate the allowable concentration of thiocyanate in subsurface soil which
would not result in exceedance of the groundwater performance standard.
For cyanide, a groundwater performance standard of 200 ug/liter was used to calculate the
subsurface soil performance standard. This number is the Safe Drinking Water Act Maximum
Contaminant Level for cyanide in drinking water. The SUMMERS groundwater model was used
to backcalculate the allowable concentration of thiocyanate in subsurface soil which would not
result in exceedance of the groundwater performance standard.
The subsurface soils at the Site currently contain concentrations of Site-related contaminants at
levels which would pose an unacceptable risk to human health for potential future users of
groundwater. Actual or threatened releases of hazardous substances from this Site, if not
addressed by implementing the response action selected in this ROD, may present an imminent
and substantial endangerment to public health, welfare, or the environment.
The performance standards for subsurface soil are contained in Table 6-9. Cleanup levels for
contaminated subsurface soil are based on protection of groundwater.
TABLE 6-9
PERFORMANCE STANDARDS FOR SUBSURFACE SOILS
CONTAMINANT
Cyanide
Thiocyanate
PERFORMANCE STANDARD (MG/KG)
0.47
8.5
Based on the soil sampling data and risk evaluation for OU2 and the groundwater monitoring
data from OU1, EPA determined that only the subsurface soils at the former Halby area present a
risk to human health and the environment. Thirteen potential source areas were eliminated from
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0034
TABLE 6-10 - STATUS OF ELIMINATED POTENTIAL SOURCE AREAS
POTENTIAL SOURCE AREAS
Old Firewater Pond
Unnamed Tributary
Old Carbon Disulfide WWTP
Old Carbon Tetrachloride WWTP
LeMoyne Swamp
LeMoyne Landfill Sulphur Spill Area
LeMoyne Swamp Sulphur Spill Area
LeMoyne Landfill
Old Chlorine Plant WWTP
Old Brine Mud Pond
Chlorine Plant North Check Pond
New Carbon Tetrachloride WWTP
LeMoyne LeCreek WWTP
STATUS
Maintenance activity to ensure adequate
drainage from the pond will eliminate need for
further action
Maintenance activity to ensure adequate
drainage from the tributary will eliminate need
for further action
Presumptive remedy: Pond capped in 1978-
79. Supplemental remedial investigation (RI)
demonstrated remedy is protective of
groundwater.
Pond being filled with sediments removed
from the Old Firewater Pond and Unnamed
Tributary. Pond will be brought to grade and
seeded. Supplemental RI demonstrated
remedy will be protective of groundwater.
No further action based on supplemental RI.
Presumptive remedy: Removal and disposal
of sulphur in an approved facility in 1994.
Presumptive remedy: Removal and disposal
of sulphur in an approved facility in 1995.
Presumptive remedy: Landfill closed and
capped 1994-95. Groundwater monitoring
and landfill maintenance required.
Presumptive remedy: Pond capped in 1978.
Groundwater monitoring and cap maintenance
required.
Presumptive remedy: Pond contents
approved for delisting as a hazardous waste
and pond capped in 1985. Groundwater
monitoring and cap maintenance required.
Presumptive remedy: Pond contents and liner
removed. Confirmatory samples taken and
pond backfilled in 1992.
Presumptive remedy: Pond drained and soils
tested. Pond backfilled in 1993.
Managed under EPA's Clean Water Act
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further consideration. Only the Halby area was carried through for further analysis. The status of
the remaining 13 source areas is summarized in Table 6-10.
7.0 DESCRIPTION OF ALTERNATIVES
EPA evaluated eight alternatives for the remediation of contaminated soil at OU#2 of the Site in
the Supplemental Feasibility Study for the Halby Area and in the Proposed Plan for the Site, along
with the No Action alternative. The site-specific alternatives analyzed in the Supplemental
Feasibility Study represented a range of distinct waste-management strategies addressing the
human health and environmental concerns. Eight remedial technologies for containment or
treatment were analyzed. Although the selected remedial alternative win be further refined as
necessary during the predesign phase, the analysis presented below reflects the fundamental
components of the various alternatives considered feasible for this She.
Time frames for achieving remediation goals were calculated for each of the alternatives. For the
No Action alternative and Alternatives 1 and 7, assumptions were made regarding the mass of
contamination in the soil and the movement of contamination through the soil. Because of the
considerable variability and complex distribution of contaminants in the former Halby area, these
assumptions have a great deal of uncertainty. Therefore, the actual time to achieve remediation
for these alternatives may vary greatly. However, the relative time frames for these alternatives
should remain the same, i.e. Alternative 7 with active soil flushing will achieve remediation goals
sooner than the No Action alternative and Alternative 1.
7.1 ALTERNATIVE NO. 0 - NO ACTION
The no action alternative is carried through the screening process as required by the National Oil
and Hazardous Substances Pollution Contingency Plan (NCP). This alternative is used as a
baseline for comparison with other alternatives that are developed. Under this alternative, EPA
would take no further action to minimize the impact soil contamination has on the groundwater.
Contamination could continue to migrate from the Halby area into the groundwater. Groundwater
cleanup would continue under OU1. Cleanup times of 13 to 26 years are estimated for this
alternative. The O&M costs of on-going groundwater treatment is estimated to be $517,000 for a
26 year period.
7.2 ALTERNATIVE NO. 1 - INSTITUTIONAL CONTROLS
Major components of this alternative would include legal restrictions to ensure no disturbance of
existing remedial systems or site soils would occur. Under this alternative, EPA would monitor
the impact soil contamination has on the groundwater. Groundwater cleanup and monitoring
would continue under the OU1 remediation. Cleanup times of 13 to 26 years are estimated for
this alternative. The cost of this alternative is estimated to be $535,000. The costs include legal
costs for deed restrictions and operations and maintenance (O&M) costs for groundwater
treatment and monitoring.
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7.3 ALTERNATIVE NO. 2 - MULTI-LAYER CAP
Major components of this alternative include site preparation and construction of a multi-layer cap
composed of a clay layer, a synthetic membrane cap with heat sealed joints, a drainage layer, a
cobblestone layer, and a cover material for vegetation. Groundwater monitoring would be
conducted for a minimum of five years to determine if leaching from this area is reduced. O&M
activities include cap maintenance, lawn care, groundwater treatment for one year, and routine
inspections and reviews. This alternative is estimated to reduce the groundwater contaminant
levels to below the performance standards within one year. The cost of this alternative is
estimated to be $884,000.
7.4 ALTERNATIVE NO. 3 - EXCAVATION AND OFFSITE DISPOSAL
This alternative would involve site preparation and excavation activities in the area. The
excavated soil would be transported for disposal at a regulated landfill. After confirmation
sampling documented that excavation was complete, the excavated area would be backfilled with
clean soil fill and revegetated. Excavation beyond 30 feet below ground surface, if required,
would require extensive shoring efforts. Groundwater monitoring would be conducted for a
minimum of two years to verify that contaminant concentrations are below the OU1 cleanup goal.
O&M costs include routine inspections and reviews. This alternative is estimated to meet soil and
groundwater performance standards within one year. The cost of this alternative is estimated to
be $6,195,000.
7.5 ALTERNATIVE NO. 4 - EXCAVATION AND EX-SITU ONSITE
BIOREMEDIATION
This alternative would involve a treatability study to determine the optimal bioremediation
techniques. After construction of the bioremediation system, contaminated soil would be
excavated and treated onsite. Confirmation sampling would verify that excavation was complete
and that soils were clean, before the treated soil was backfilled into the excavation area.
Groundwater monitoring would be conducted for a minimum of two years to verify that
contaminant concentrations are below the OU1 cleanup goals. O&M costs include routine
inspections and reviews. This alternative is estimated to meet soil and groundwater performance
standards within one year. The cost of this alternative is estimated to be $11,720,000.
7.6 ALTERNATIVE NO. 5 - EXCAVATION AND EX-SITU BIOREMEDIATION/
IN-SITU SOIL FLUSHING
This alternative would involve a treatability study to determine the optimal bioremediation
techniques and test to determine design parameters for the soil flushing system. The silty clay
layer of soil would be excavated and treated by bioremediation. Because of safety concerns with
deep excavation activities, the remaining soil would be treated by soil flushing to move
contaminants into the groundwater for capture and treatment. Since the site already has
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contaminated groundwater under OUI , in-situ soil flushing was considered a viable means for soil
remediation. Sampling would be conducted to demonstrate the effectiveness of the
bioremediation and soil flushing. Treated soil which was documented to be clean would be
backfilled into the excavated area. Groundwater monitoring would be conducted for a minimum
of two years to verify that contaminant concentrations are below the OUI cleanup goals. O&M
costs include routine inspections and reviews. This alternative is estimated to meet soil
performance standards within five to ten years. The cost of this alternative is estimated to be
$5,409,000.
7.7 ALTERNATIVE NO. 6 - EXCAVATION AND OFFSITE DISPOSAL/
IN-SITU FLUSHING
This alternative would involve tests to determine the design parameters for the soil flushing
system. The silty clay layer of soil would be excavated and transported for disposal at a regulated
landfill. The remaining soil would be treated by soil flushing to move contaminants into the
groundwater for capture and treatment. Since the site already has contaminated groundwater
under OUI, in-situ soil flushing was considered a viable means for soil remediation. Sampling
would be conducted to demonstrate the effectiveness of the excavation and soil flushing. The
excavated area would be backfilled with clean soil fill. Groundwater monitoring would be
conducted for a minimum of two years to verify that contaminant concentrations are below the
OUI cleanup goals. O&M costs include routine inspections and reviews. This alternative is
estimated to meet soil performance standards within six to twelve years. The cost of this
alternative is estimated to be $3,465,000.
7.8 ALTERNATIVE NO. 7 - IN-SITU SOIL FLUSHING
This alternative involves flushing the affected soil with water to move the contamination into the
groundwater and to accelerate the natural breakdown of contamination into non-toxic chemicals.
Since the site already has contaminated groundwater under OUI , in-situ soil flushing was
considered a viable means for soil remediation. Implementation of this remedy would involve
tests to determine design parameters for the soil flushing system. The soil would be treated by
soil flushing to move contaminants into the groundwater for capture and treatment. Groundwater
monitoring would begin after construction of the remedy is complete and would be conducted for
a period of time adequate to establish that the remedy is effective. O&M includes groundwater
treatment and routine inspections and reviews. This alternative is estimated to meet soil
performance standards within six to twelve years. The cost of this alternative is estimated to be
$501,000.
7.9 ALTERNATIVE NO. 8 - ASPHALT CAP
This alternative is similar to Alternative 2, except the cap is less complex. Implementation of this
alternative would involve site preparation, installation of a gravel base, and installation of an
asphalt pavement. Groundwater monitoring would be conducted for a minimum of five years to
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determine If leaching from this area is reduced. O&M activities include cap maintenance, lawn
care, groundwater treatment for one year, and routine inspections and reviews. This alternative is
estimated to reduce the groundwater contaminant levels to below the performance standards
within one year. The cost of this alternative is estimated to be $598,000.
8.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES
This section of the ROD provides the basis for determining which alternative provides the best
balance with respect to the statutory balancing criteria in Section 121 of CERCLA and in 40 CFR
Section 300.430 of the NCP. The major objective of the Supplemental FS was to develop,
screen, and evaluate alternatives for the remediation of Operable Unit Two at the site. The
remedial alternatives selected from the screening process were evaluated using the following nine
evaluation criteria:
• Overall protection of human health and the environment.
• Compliance with applicable and/or relevant and appropriate Federal or State public health
or environmental standards.
• Long-term effectiveness and permanence.
• Reduction of toxicity, mobility, or volume of hazardous substances or contaminants.
• Short-term effectiveness, or the impacts a remedy might have on the community, workers,
or the environment during the course of implementing it.
• Irnplementability, that is, the administrative or technical capacity to carry out the
alternative.
• Cost-effectiveness considering costs for construction, operation, and maintenance of the
alternative over the life of the project.
• Acceptance by the State.
Acceptance by the Community.
The NCP categorizes the nine criteria into three groups:
(1) Threshold Criteria - overall protection of human health and the environment and
compliance with ARARs (or invoking a waiver) are threshold criteria that must be satisfied in
order for an alternative to be eligible for selection;
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(2) Primary Balancing Criteria - long-term effectiveness and permanence; reduction of
toxicity, mobility, or volume; short-term effectiveness; implementability, and cost are primary
balancing factors used to weigh major trade-offs among alternative hazardous waste management
strategies; and
(3) Modifying Criteria - state and community acceptance are modifying criteria that are
formally taken into account after public comment is received on the proposed plan and
incorporated in the ROD.
The selected alternative must meet the requirement for overall protection of human health and the
environment and comply with all ARARs or be granted a waiver for compliance with ARARs.
Any alternative that does not satisfy both of these requirements is not eligible for selection. The
Primary Balancing Criteria are the technical criteria upon which the detailed analysis is primarily
based. The final two criteria, known as Modifying Criteria, assess the public's and the state
agency's acceptance of the alternative. Based on these final two criteria, EPA may modify aspects
of a specific alternative.
The following analysis is a summary of the evaluation of alternatives for remediating the Stauffer
LeMoyne OU2 Superfund Site under each of the criteria. A comparison is made between each of
the alternatives for achievement of a specific criterion.
Threshold Criteria
8.1 OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
Overall protection of human health and the environment addresses whether each alternative
provides adequate protection of human health and the environment and describes how risks posed
through each exposure pathway are eliminated, reduced or controlled through treatment,
engineering controls and institutional controls. The no-action alternative and alternative 1 would
not involve any active remediation efforts. However, natural flushing would move contamination
from the soil into the groundwater where it would be captured and treated by the OU1 system.
Therefore, human health and the environment would be protected after approximately 13 to 26
years. Alternative 1 would provide an additional level of protection by using institutional controls
to prevent disturbance of surface or subsurface soils which would interfere with the movement of
contamination from the soil into the groundwater. Alternative 7 utilizes active soil flushing to
remove contamination from the soil into the groundwater where it would be captured and treated
by the OU1 system. Alternatives 2 and 8 would prevent contamination from migrating into the
groundwater, but would require perpetual cap maintenance. Any breach in the cap would
potentially allow contamination to migrate into the groundwater. The remaining alternatives
provide adequate protection through proper disposal or treatment.
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8.2 COMPLIANCE WITH ARARS
Section 121(d) of CERCLA requires that remedial actions at CERCLA sites at least attain legally
applicable or relevant and appropriate Federal and State requirements, standards, criteria, and
limitations which are collectively referred to as "ARARs," unless such ARARs are waived under
CERCLA Section 121(d)(4). Applicable requirements are those substantive environmental
protection requirements, criteria, or limitations promulgated under Federal or State law that
specifically address hazardous substances, the remedial actions to be implemented at the site, the
location of the site, or other circumstances present at the site. Relevant and appropriate
requirements are those substantive environmental protection requirements, criteria, or limitations
promulgated under Federal or State law which, while not applicable to the hazardous materials
found at the site, the remedial action itself, the site location or other circumstances at the she,
nevertheless address problems or situations sufficiently similar to those encountered at the site
that their use is well-suited to the she. Compliance with ARARs addresses whether a remedy will
meet all of the applicable or relevant and appropriate requirements of other Federal and State
environmental statutes or provides a basis for invoking a waiver.
No chemical specific ARARs exist for soil contamination. Chemical specific ARARs for
groundwater are found in the Safe Drinking Water Act (40 CFR 141) in the form of Maximum
Contaminant Levels (MCLs) for public water systems. All remedies would be implemented to
ultimately reduce migration of contaminants from subsurface soil, so that MCLs would be met.
Location-specific ARARs address remedial activities in specific sensitive locations. Some areas of
contamination at the site involve wetlands or 100-year floodplains. Operable Unit 2 of the Site is
not within an area affecting national wildlife, scenic, or recreational areas or within environmental
significant agricultural areas. Neither is the site a critical habitat area or on property which is
included on the National Register of Historic Places. No location-specific ARARs were identified
for OU2 of the Site.
Action-specific ARARs are usually technology or activity based requirements or limitations on
actions taken with respect to hazardous substances. All alternatives would be implemented to
comply with action-specific ARARs. All excavation, storage, handling, treatment and disposal of
contaminated soil would be conducted in accordance with applicable or relevant and appropriate
RCRA requirements. Off-site disposal of contaminated soil under Alternatives 3 or 6 would be at
a permitted RCRA Subtitle C, or Subtitle D landfill, as appropriate. During treatment, air
emissions from the site would be monitored to ensure compliance with the Clean Air Act. Air
monitoring would be conducted to ensure that contaminant concentrations do not exceed levels
considered to be safe for human health. If levels are exceeded, mhigative procedures would be
employed to prevent harmful levels of air emissions from impacting on-site workers or from
leaving the Site. EPA developed soil performance standards for cyanide and thiocyanate, since
chemical-specific ARARs did not exist. Alternatives 2 and 8 would not comply with the soil
performance standards which were developed. However, implementation of alternative 2 or 8
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would result in OU1 performance standards for groundwater being achieved. The remaining
alternatives would be implemented to comply with the soil performance standards.
Primary Balancing Criteria
8.3 LONG-TERM EFFECTIVENESS AND PERMANENCE
Long-term effectiveness and permanence refers to expected residual risk and the ability of a
remedy to maintain reliable protection of human health and the environment over time, once
clean-up levels have been met. This criterion includes the consideration of residual risk and the
adequacy and reliability of controls.
Alternatives 2 and 8 would not remove contaminated soil from the Halby area. However, the cap
would be effective in protecting groundwater by reducing migration of contamination into the
groundwater. The cap would require yearly maintenance to ensure protection of groundwater.
Alternatives 3 and 4 would provide long-term effectiveness and permanence by removing or
treating the entire source area. Alternatives 5 and 6 would provide long-term effectiveness and
permanence by removing or treating a portion of the source and by flushing remaining
contamination into the groundwater for capture and treatment. Alternative 0,1 and 7 would
provide long-term effectiveness and permanence by flushing contamination into the groundwater
for capture and treatment.
8-4 REDUCTION OF TOXICITY. MOBILTTY OR VOLUME THROUGH TREATMENT A
Reduction of toxicity, mobility, or volume through treatment refers to the anticipated performance
of the treatment technologies that may be included as part of the remedy. Although Alternatives 2
and 8 would not reduce toxicity, mobility, or volume through treatment, they would reduce
mobility of the contaminants through the soil, If the cap is properly installed and maintained. Over
time, contaminant levels in the existing areas of contamination may decrease through natural
attenuation. Alternative 3 and the landfill portion of Alternative 6 also would not reduce
toxicity, mobility, or volume through treatment. However, placement of the soil in a permitted
landfill would reduce mobility of the contaminants. Alternatives 4 and 5 would reduce toxicity,
mobility, and volume through treatment of all or some of the contaminated soil. Flushing
contaminants into the groundwater in Alternatives 0,1,5,6 and 7 would reduce toxicity and
volume, when contaminants are captured and treated by the groundwater remedy system.
8.5 SHORT-TERM EFFECTIVENESS
Short-term effectiveness addresses the period of time needed to implement the remedy and any
adverse impacts that may be posed to workers and the community during construction and
operation of the remedy until clean-up goals are achieved. For all alternatives involving
construction, impacts such as noise, dust, and odors can be controlled with standard procedures.
There would be potential risk to workers during excavation and treatment of soils and
4 ?
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construction of the cap, primarily associated with equipment movement and exposure to
contaminated dust. Air monitoring, on-site and at the site boundary, and engineering controls
would control the potential for exposure. Workers would be required to wear appropriate levels
of protection to avoid exposure during excavation and treatment. For Alternatives 4 and 5
treatability studies would be conducted to determine how to prevent undesirable reactions during
treatment.
Alternatives 0 and 1 require the longest time frames to meet soil and groundwater cleanup
standards. Of the alternatives involving active remediation, Alternatives 4 and 5 would require
longer time frames for construction and implementation. Of the active remediation alternatives,
Alternatives 5,6 and 7 would require longer time frames for meeting soil and groundwater cleanup
standards.
8.6 IMPLEMENT ABILITY
Implementability addresses the technical and administrative feasibility of a remedy from design
through construction and operation. Factors such as availability of services and materials,
administrative feasibility, and coordination with other governmental entities are also considered.
Alternatives 0 and 1 are most easily implemented, since no active remediation is involved.
Alternatives 2,3 and 8 are easily implemented using readily available materials, equipment, and
labor. Alternative 4 involves a technology for which engineering services are available. The
technology has proven effective in the past. This alternative would require treatability studies to
resolve operational issues Alternative 5 involves two technologies for which services, equipment,
and labor are available. Treatability studies for bioremediation would be necessary. Services,
equipment and labor to implement Alternatives 6 and 7 are available. For Alternatives 3 through
6, excavation beyond 30 feet below ground surface, if require, would require extensive shoring
methods, which are available.
8.7 COST
The non-active remediation alternatives are the most cost effective alternatives. Of the active
remediation alternatives, the treatment remedies are most costly than capping and off-site disposal
alternatives. However, the treatment remedies provide more permanence and meet the regulatory
preference to reduce toxicity, mobility, and volume through treatment. Of the treatment
alternatives, bioremediation would be the most costly, due to the need for treatability studies and
the increased labor requirements to construct and operate the system.
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Modifying Criteria
8.8 STATE ACCEPTANCE
The State of Alabama, as represented by the Alabama Department of Environmental Management
(ADEM), has been the support agency during the Remedial Investigation and Feasibility Study
process for the Stauffer LeMoyne OU2 site. In accordance with 40 CFR 300.430, as the support
agency, ADEM has provided input during this process. The State of Alabama, as represented by
ADEM, has concurred with the selected remedy.
8.9 COMMUNITY ACCEPTANCE
Comments were received on the proposed plan for Operable Unit 2 of the Site. The comments
and their responses are summarized in the responsiveness summary in Attachment 2.
9.0 SUMMARY OF SELECTED REMEDY
Based upon consideration of the requirements of CERCLA, the NCP, the detailed analysis of
alternatives and public and state comments, EPA has selected a remedy for Operable Unit 2 of the
Site. The selected remedy is Alternative 7, In-shu Soil Flushing. This remedy is selected because
it provides cleanup of contaminated subsurface soil within six to twelve years, but has the lowest
cost of the alternatives.
9.1 SOIL REMEDY
Approximately 39,700 cubic yards of subsurface soil containing thiocyanate and cyanide above
the performance standards are present in the Halby Area. Previous data indicate that natural soil
flushing is moving subsurface soil contamination from the soil into the groundwater where it is
being captured by the existing groundwater pump-and-treat system. The selected remedy for
contaminated soils accelerates this natural process with an in-situ soil flushing system. This
remedy provides for the following:
• Institutional controls to restrict the She from being used as residential property and to
restrict any construction on the former Halby area which would interfere with the
construction and operation and maintenance of the selected remedy,
• Construction of a soil flushing system to accelerate the migration of contaminants from the
subsurface soil into the groundwater where it will be captured and treated by the existing
OU1 groundwater remedy,
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• Monitoring of subsurface soil for cyanide and thiocyanate on an annual basis to determine
if contaminants are moving into the ground water in a controlled manner where they will be
captured and treated by the OU1 groundwater remedy, and
• Periodic reporting of annual monitoring results to EPA.
Because a risk assessment for a future residential scenario was not performed for OU2 of the Site,
institutional controls restricting the Site from use as residential property must remain in place until
a human health risk assessment is conducted which demonstrates to EPA that the Site does not
pose any unacceptable risks to future residents. The institutional controls restricting any
construction on the former Halby area which would interfere with the operation and maintenance
of the selected remedy can be removed when EPA determines that the subsurface soil monitoring
demonstrates that the performance standards have been met.
This remedy is contingent upon the continued operations and maintenance of the Operable Unit 1
groundwater pump and treatment system. Accordingly, if the groundwater pump and treatment
system is not operated and maintained for the life of this remedy for OU2, EPA may, at its sole
discretion, select an alternative remedy for OU2. Similarly, if, at any time, the selected remedy
for OU2 is found to be ineffective at reducing subsurface soil contaminant concentrations, EPA
may, at its sole discretion, select an alternative remedy for OU2.
TABLE 9-1 - SUBSURFACE SOIL PERFORMANCE STANDARDS
Contaminant
Cyanide
Thiocyanate
Performance Standard
0.47 mg/kg (ppm)
8.5 mg/kg (ppm)
Basis for Performance Standard
Compliance with MCLs
Risk assessment (HQ=1)
MCL - Maximum Contaminant Level (EPA Safe Drinking Water Act)
ppm - parts per million
HQ - Hazard quotient
In order to facilitate this remedy, the former Halby area, which includes the location of the former
Halby facility, including the Halby Treatment Pond, located in the northwest portion of the
Stauffer LeMoyne site, is designated as an Area of Contamination (AOC) for purposes of this
ROD. All waste managed within the AOC must comply with the requirements set out in this
ROD for soil remediation. The AOC also includes suitable areas in close proximity to the
contamination necessary for implementation of the remedy selected in this ROD.
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9.2 PERFORMANCE STANDARD? FOR SOIL
Subsurface soil performance standards were developed for the protection of groundwater.
Remediation of subsurface soils to these performance standards will reduce migration of
contamination to groundwater, so that groundwater will not pose an unacceptable risk to
potential users of groundwater as a drinking water source. The subsurface soil performance
standards are presented in Table 9-1.
9.3 CONFIRMATION TESTING
Soil testing shall be conducted on the site to determine the effectiveness of meeting the soil
performance standards outlined in Table 9-1. This samplbg will be conducted in accordance with
an EPA approved sampling and analysis plan. Performance standards will be met only when the
confirmatory sampling shows to EPA that subsurface soil samples have been remediated to a level
at or below the performance standards. Subsurface soil sampling and analysis shall be conducted
no less frequently that every 12 months.
Confirmation testing may also require the installation and monitoring of additional piezometers.
The purpose of the piezometers is to verity groundwater capture from beneath the former Halby
area, as predicted in groundwater models. The piezometers shall be monitored on an annual basis.
The piezometers will be required if EPA determines that existing monitoring wells do not
adequately confirm the capture of the contaminants. If data from the piezometers and other
monitoring wells indicate that groundwater capture from beneath the former Halby area is not
occurring as predicted in groundwater models, EPA may, at its sole discretion, select an
alternative remedy for OU2.
9.4 COST
For in-situ soil flushing, the estimated present worth cost of the remedy is approximately
$501,000. These costs include fees for institutional controls, as well as operations and
maintenance costs. These estimated costs include $197,000 in capital costs and $304,000 in
operation and maintenance costs, including a 20% contingency.
9.5 EXPECTED OUTCOME OF THE SELECTED REMEDY
The selected remedy addresses contaminated subsurface soil which is continuing to contaminate
underlying groundwater. The remedy will maintain the current land use of the Site, which is
industrial use. The contamination from the Halby area is expected to attenuate to acceptable
levels (below the performance standards) within six to twelve years.
38
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5 9
OC46
TABLE 9-2 - SUMMARY OF SELECTED REMEDY COSTS
Capital Colt*
Site preparation
Soil flushing components
Direct Construction Cost (DCT)
Indirect Construction Cost (15% of
DCT)
Construction Total (CT)
Permitting and Legal
Design/Resident Engineering (10% of
CT)
Total Capital Costs
Contingency (20%)
Quantity
1
1
Unit
LS
LS
Unit Cost
$57,200
$41,100
Estimated
Installed Cost
$57,200
$41,100
$98,300
$15,000
$113,000
$40,000
$11,000
$164,000
$33,000
O&M CoiU
Site Inspections
Repair/Maintenance
Biennial Groundwater Monitoring
(Annualized)
Recovered Water Treatment
5-Year Review of Effectiveness
(Annualized)
Total Annual O&M Cost
SYear Present Worth Cost
Projected O&M Cost*
TOTAL COST
96
2
1
1
1
Hour
LS
LS
LS
LS
$70
$1,200
$3,200
$25,000
$1,800
$6,700
$2,400
$3,200
$25,000
$1,800
$39.100
$253,000
$304,000
$501,000
Projected O&M cost includes 20% contingency
LS - Lump sum
Notes:
1) Estimated costs are based on conceptual evaluation of the potential remedy and are subject to change based on
preliminary and final design
2) Unit costs were obtained from Means Building Construction Cost Data 1995, as well as professional experience
39
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5 9 0047
Under its legal authorities, EPA's primary responsibility at Superfund sites is to undertake
remedial actions that achieve adequate protection of human health and the environment. In
addition, Section 121 of CERCLA establishes several other statutory requirements and
preferences. These specify that, when complete, the selected remedial action for this Site must
comply whh applicable or relevant and appropriate environmental standards established under
Federal and State environmental laws. The selected remedy also must be cost-effective and utilize
permanent solutions and alternative treatment technologies or resource recovery technologies to
the maximum extent practicable. Finally, the statute includes a preference for remedies that
employ treatment that permanently and significantly reduce the volume, toxicity, or mobility of
hazardous wastes as their principal element. The following sections discuss how the selected
remedy meets these statutory requirements.
10.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The selected remedy protects human health and the environment through monitoring the isolation
and treatment of threats at Operable Unit 2 of the Site in the contaminated subsurface soil. The
selected remedy provides protection of human health and the environment by reducing and
controlling risk through movement of contamination from the subsurface soils to the groundwater
and treatment of groundwater (though the existing OU1 remedy). Contamination in the
subsurface soils at Operable Unit 2 of the Site will be moved by in-situ soil flushing into the
groundwater, where contaminants will be captured and treated. The subsurface soils will be
cleaned up to levels that are protective of groundwater.
10.2 ATTAINMENT OF THE APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS (ARARs)
Remedial actions performed under CERCLA must comply with all applicable or relevant and
appropriate requirements (ARARs). All alternatives considered for OU2 of the Site were
evaluated on the basis of the degree to which they complied with these requirements. The
selected remedy was found to meet or exceed all ARARs, which are listed in Table 10-1.
Waivers
Section 121 (d){4)(C) of CERCLA provides that an ARAR may be waived when compliance with
an ARAR is technically impracticable from an engineering perspective. No waivers are necessary
with respect to the selected remedy.
40
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59 0048
Other Guidance To Be Considered
Other Guidance To Be Considered (TBCs) include health based advisories and guidance. TBCs
have been utilized in estimating incremental cancer and non-cancer risk numbers for the site. The
risk numbers are evaluated relative to the normally accepted point of departure risk range of 10"4
to 10"* or a hazard quotient of 1.
10.3 COST EFFECTIVENESS
Cost effectiveness is determined by comparing the cost of all alternatives being considered with
their overall effectiveness to determine whether the costs are proportional to the effectiveness
achieved. Overall effectiveness is defined by three of the five balancing criteria: long-term
effectiveness, short-term effectiveness, and reduction of toxicity, mobility, or volume through
treatment. EPA evaluates the incremental cost of each alternative as compared to the increased
effectiveness of the remedy. The selected remedy provides long-term effectiveness and reduction
of toxicity, mobility, or volume through treatment. Other alternatives provide greater short-term
effectiveness, in shorter time frames for completion. However, the costs of these alternatives are
much greater. Given that groundwater is not currently used as a drinking water source and is not
anticipated to be used in the next 30 years, the selected remedy is the most cost-effective. EPA
chose a remedy which accelerates soil remediation over natural flushing because the remedy is
more cost effective. In addition, uncertainties in calculating remediation times make it prudent to
select a remedy which has greater short term effectiveness when practicable.
The estimated cost of EPA's selected remedy is $501,000. The selected remedy, Alternative 7, is
the least costly alternative.
10.4 UTILIZATION OF PERMANENT SOLUTIONS TO THE MAXIMUM EXTENT
PRACTICABLE
The selected remedy utilizes permanent solutions to the maximum extent practicable by using
treatment to permanently reduce contaminant levels. This remedy provides long-term
protectiveness by accelerating and monitoring the migration of contaminants from subsurface soils
into the groundwater where it will continue to be captured and treated by the OU1 remedy.
Reduction of toxicity, mobility, or volume through treatment is provided by removing
contaminants from the subsurface soil by flushing contaminants into the groundwater.
Contaminants will be captured and removed from the groundwater by the OU1 remedy.
Alternative 1, Institutional Controls, would provide the same protection, but over a much longer
time period. The capping alternatives, Alternatives 2 and 8, are not as effective in providing long-
term effectiveness, since contamination will remain in the subsurface soil. In addition, these
remedies do not provide reduction of toxicity, mobility, or volume through treatment. Alternative
3, excavation and off-site disposal, provides long-term effectiveness but does not reduce toxicity,
41
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5 9 0049
mobility, or volume through treatment. The excavation and treatment alternatives, Alternatives 4,
5, and 6, provide long-term effectiveness and reduction of toxicity, mobility, or volume through
treatment. However, these alternatives are not cost effective. Cost and long-term effectiveness
were the most decisive criteria in the selection decision.
10.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
The statutory preference for treatment will be met because the selected remedy treats subsurface
soil contamination by flushing contamination into the groundwater where contamination will be
captured and treated under the Operable Unit I remedy.
10.6 FIVE-YEAR REVIEW REQUIREMENTS
This remedy is based on risk assessments for industrial use scenarios. Contamination may be
present which would restrict the use of this property for residential use. Because this remedy may
result in hazardous substances remaining on-site above levels that allow for unlimited use and
unrestricted exposure, a review win be conducted within five years after initiation of remedial
action to ensure that the remedy continues to provide adequate protection of human health and
the environment.
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The subsurface soil performance standard for cyanide was changed from 0.64 mg/kg to 0.47
mg/kg. The 0.64 mg/kg proposed standard in the proposed plan was a typographical error. In
addition, the cost estimate for each alternative was re-evaluated due to the age of some of the
estimates. Estimates for all alternatives were modified based on more recent and accurate cost
data. The cost of each alternative changed following release of the proposed plan. The most
significant cost update was in the cost of treating contaminated groundwater from the active soil
flushing alternative (Alternative 7). This change resulted in the total cost for Alternative 7
changing from $3,939,300 to $501,000. The no-action alternative (Alternative 0) and the
institutional controls alternative (Alternative 1) also changed significantly due to the addtion of
groundwater treatment costs to the cost estimates. EPA understands that the revisions occurred
due to the use of more accurate cost measurements, in place of the assumptions previously used
by the parties that prepared the RI/FS. Both sets of data are available for review and comparison
in the Administrative Record.
42
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TABLE 10-1 APPLICABLE OR RELEVANT AND APPROPRIATE REGULATIONS
ACTION-SPECIFIC ARARS
Standard, Requirement,
Criteria, or Limitation
Citation
Applicable or Relevant
& Appropriate
Description
Federal
Occupational Safely and Health
Act
Clean Water Act
Clean Air Act
National Ambient Air Quality
Standards
(NAAQS)
Resource Conservation and
Recovery Act
Characteristics of Hazardous Waste
20 USC Section 651-
678
40 CFR 122.28
42 USC Section 7401-
7642
40 CFR Part 50
42 USC Section 6901-
6907
40 CFR 261 .24
Applicable
Relevant and appropriate
Applicable
Applicable
Applicable
Regulates worker health and safety.
Establishes standards under the
National Pollutant Discharge
Elimination System (NPDES) for
discharges to surface waters
Treatment technology standard for
emissions to air
« incinerators
•surface impoundments
•waste piles
•landfills
•fugitive emissions
Describes methods for determining
hazardous waste characteristics
en
43
O
o
un
c-
-------
ACTION-SPECIFIC ARARS
Standard, Requirement,
Criteria, or Limitation
Releases from Hazardous Waste
Management Units
Post-closure notices
Citation
40 CFR 264.90-
264.101
40 CFR 264.1 19
Applicable or Relevant
& Appropriate
Relevant & appropriate
Relevant & appropriate
Description
Monitor and respond to releases to
uppermost aquifer beneath SWMU
Requires post-closure notices for
hazardous waste disposal units
State
NAAQS Paniculate Matter
Underground Injection Control
Groundwater Protection
Land Division Solid Waste Program
Procedures
ADEM Section R.335-
3-1.03
ADEM Section R.335-
6-8
ADEM Section R.335-
6-10
ADEM Section R.335-
13-4 and R.335-13-5
Applicable
Relevant and appropriate
Applicable
Applicable
Regulates fugitive particulate
emissions
Regulates soil flushing
Regulates soil flushing
Procedures for obtaining disposal
permits
CHEMICAL-SPECIFIC ARARS
Standard, Requirement, Criteria,
or Limitation
Citation
Applicable or Relevant
& Appropriate
Description
Federal
Safe Drinking Water Act
40 CFR 141
Relevant and
Appropriate
Establishes primary drinking water
regulations and related regulations
applicable to public water systems.
en
44
o
o
en
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r o
APPENDIX 1
RESPONSIVENESS SUMMARY
STAUFFER CHEMICAL CO. (LEMOYNE PLANT) SITE
OPERABLE UNIT 2
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5 9 OC53
Responsiveness Summary
Record of Decision
Stauffer LeMoyne Site
Operable Unit Two
Axis, Mobile County, Alabama
^>S'f™?^£ ^rotection Agency (EpA) held a public comment period from July 31
1 998 to August 31. 1 998 for interested parties to give input on EPA's Proposed Plan for Remedial
Action at Operable Unit Two (OU 2) of the Stauffer LeMoyne (Stauffer jluperfimd S
Mobile County, Alabama. EPA offered the opportunity for a public mBeftHo^
meetui was no
D
meetuig was not requested. The public comment period wastendedadi 30 dav
fromAugustSl, 1998 to September 30, 1998, after EPA received a request for
A responsiveness summary is required to document how EPA addressed citizen comments and
thC PUbUc C0mment I"** AD com!nem™
mto the amended fiMl decision of the remedial
This responsiveness summary for the Stauffer Site is divided into the following sections.
I. Overview - This section discusses the recommended alternative for remedial action
and the public reaction to this alternative.
H. Background on Community Involvement and Concerns - This section provides a
brief history of community interest and concerns regarding the Stauffer Site.
III. Summary of Major Questions and Comments Received During the 1996 Public
Comment Period and EPA's Responses - This section presents comments
submitted during the public comment period and provides the responses to these
comments.
IV. Summary of Major Questions and Comments Received During the 1998 Public
Comment Period and EPA's Responses
V. Concerns to be Addressed in the Future- This section discusses community
concerns of which EPA should be aware during remedial design.
/
I. Overview
The remedial alternatives for the Stauffer site were presented to the public in an Proposed Plan
released on July 31, 1998. The public comment period was Jury 31/1998
1998. A public notice was published in the Mobile
indicated the EPA wold hold a public
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5 9 0054
to the public comment period was published in the Mobile Register on SentemW i 1993 A
public meeting was not requested by the public. '
EPA has organized the work at this Site into three phases or operable units (OUs). OUI involves
the groundwater beneath the Stauffer LeMoyne site, as well as the Stauffer Cold Creek site
Current remedial actions on OUI are addressing groundwater contamination underneath both
Sites. Operable unit three addresses the swamp area located adjacent to the Stauffer LeMoyne
and Stauffer Cold Creek Sites. This responsiveness summary addresses comments on operable
unit two, which involves source contamination at the Stauffer LeMoyne Site. The contaminated
area requiring remediation is limited to the former Halby area of the Site.
For the contaminated soils at OU2, the selected remedy is Alternative 7: In-situ Soil Flushing The
estimated cost of this alternative is $501,000. This remedy accelerates natural processes which
are moving contamination from the subsurface soil into the groundwater where it will be captured
and treated. Institutional controls will restrict use of the Site for residential use and will limit the
use of surface and subsurface soils in the former Halby area of the Site until the subsurface soil
performance standards are met. Regular monitoring of subsurface soil will be conducted to
determine if performance standards have been met. In addition, groundwater monitoring
piezometers will be installed to confirm groundwater modeling.
This selected remedy differs from the proposed plan recommended remedy in that deed
restrictions to prevent residential use of the property were added to the remedy.
IL Background on Community Involvement and Concerns
EPA has taken the following actions to ensure that interested parties have been kept informed and
given an opportunity to provide input on activities at the Stauffer OU2 Site.
Multiple meetings have been held regarding site work at the Stauffer LeMoyne site The Satsuma
Branch Library in Satsuma, Alabama was chosen as the local information repository for the Site
Fact sheets describing remedial investigations at the Site were issued in 1986 and 1989 A public
comment period for operable unit one ran from July 13, 1989 to August 13 1989 A public
meeting was held on July 27, 1989. For operable unit three, availability sessions were held in
February 1991 and April 1992. The public comment period ran from June 15 1993 to July 14
1993. A public meeting was held on June 29, 1993. '
The public comment period on the proposed plan for the operable unit two ROD was July 3 1
1998 through September 30, 1998. EPA published notice that it would hold a public meeting
upon request of the community. However, a public meeting was not requested by the public The
admmistrative record was available to the public at both the information repository maintained at
the Satsuma Branch Library and at the EPA Region IV Library at 61 Forsyth Street in Atlanta
Georgia. The notice of availability of the proposed plan and administrative record were published
in the Mobile Register on July 3 1, 1998. Notice of the extension of the comment period was
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5 9 0055
published in the Mobile Register on September 3, 1998
m. Summary of Major Questions and Comments Received During the Public Comment
Period and EPA's Responses
1. Comment: Several commenters supported the proposed remedy.
EPA Response: EPA concurs.
2. Comment: Several commenters stated that they preferred the alternative of excavating
contaminated soil and disposing the soil in an off-site landfill.
EPA Response: The excavation and off-site disposal alternative does not result in
treatment of contamination to reduce toxicity, mobility, or volume of contamination. The
selected alternative will move contamination into the groundwater, where the existing
pump and treat system will capture and treat the contamination. In addition, the cost for
the excavation and off-site disposal alternative is not justified given the current site
conditions (e.g., no current unacceptable risk to workers, additional groundwater
contamination which restricts groundwater use).
3. CoPMient: One commenter expressed concern that contamination may be migrating off-
site into residential property. The commenter asked if the remedy would guarantee the
elimination of future problems.
EPA Response; Monitoring data from OU1 wells indicates that contamination has not
migrated into residential property. The selected remedy is intended to be a permanent
solution for contaminated areas in operable unit two of the Site. Contamination from the
soils will continue to be flushed into the groundwater, where the existing pump and treat
system captures and treats the contamination. EPA will periodically inspect the
groundwater system to ensure that it is operating effectively.
4. Comment: One commenter stated that the proposed plan incorrectly lists cyanide as a
contaminant of concern. The commenter discussed previous soil sampling which
suggested that the total cyanide detections were false positives arising from conversion of
thiocyanate to cyanide during analysis.
EPA Response: EPA reviewed the report submitted by the commenter entitled "Stauffer
LeMoyne Superfund Site, Former Halby Area Soil and Groundwater 1998 Sampling
Results," dated July 6, 1998. The report does not unquestionably support the contention
that the cyanide detected in the soil samples is an artifact of the analytical process. While
the data produced by this effort may ultimately support the theory of interferences, the
report is inconclusive with respect to the occurrence of false positive cyanide values.
Therefore, cyanide will be retained as a contaminant of concern.
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59 OG56,
5. Comment: One commenter stated that the risk assessment in the proposed plan is
premised on an inaccurate future use scenario for groundwater. The commenter pointed
out that the groundwater is not currently used as a source of drinking water, that the
groundwater underlying the Site is classified as Class II and so is not anticipated to be
used as a drinking water source, that a public drinking water source is available in the area
which has sufficient capacity for projected future use, and that there is no reasonably
anticipated future use of groundwater at this industrial site which could result in human
exposure risks, because the duration of the site-wide groundwater cleanup is estimated at
approximately 30 years.
EPA Response: Although the groundwater beneath the Site is not currently used as a
drinking water source, it has been used as a drinking water source in the past and is
classified as Class II groundwater. According to EPA's "Guidelines for Ground-Water
Classification under the EPA Ground-Water Protection Strategy," Class II groundwater
includes groundwater which is currently used, or potentially available, for drinking water
and other beneficial use. Future use is not limited to a 30 year time frame. Remediation
of this groundwater aquifer will ensure the long-term availability of adequate water
supplies. The decision to protect this aquifer is valid.
6. Comment: One commenter stated that the proposed plan mistakenly estimates the duration
of groundwater remediation as five years. The feasibility study indicated that a period of 5
- 10 years would be required for the in-situ flushing system.
EPA Response: EPA agrees. The omission of the 5-10 year time range was an error.
Based on new data, the time frame has been changed to six to twelve years
7. Comment: One commenter stated that the recommended remedy is not consistent with the
NCP. The proposed plan describes the selected remedy as being equal to the Institutional
Controls alternative in all aspects except cost and short-term effectiveness. The
commenter stated that no basis exists for accelerating the soil cleanup in the Halby area,
since site-wide groundwater cleanup will not occur for an estimated 30 years. The
commenter further states that an accelerated remedy is unjustified, since the groundwater
beneath the Site is not currently, nor in the near-term, anticipated to be a source of
drinking water.
EPA Response: Based on new cost data, the selected remedy is the least costly alternative.
In addition, it results in cleanup of contaminated subsurface soils in significantly less time
than the Institutional Controls alternative.
The recommendation of an active soil flushing alternative was partly based on Akzo
Nobel's desire to have unrestricted use of the Halby area property. Akzo Nobel has
indicated that its only current plan for the Halby area is for a railroad spur. A railroad
spur could possibly be constructed so that it would not interfere with the selected remedy.
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5 9 0057
To EPA's knowledge, a 30 year time frame for groundwater remediation at the Site is
undocumented in the Site files. The Record of Decision (ROD) statement that
groundwater well monitoring will continue for 30 years was based on a RCRA
requirement to monitor closed RCRA facilities for 30 years. However, the ROD does not
provide a time frame for the groundwater cleanup. The 1992 preliminary remedial design
report included groundwater modeling which demonstrated that 1 to 2 years would be
required to capture groundwater from the contaminated areas. However, the report does
not predict the time frame for reducing groundwater contamination to acceptable levels
The recommendation of an active soil flushing alternative is based on EPA's desire to
accelerate subsurface soil clean up, since the potential exists for the groundwater to be
cleaned in a shorter period of time than 30 years.
8. Comment: One commenter stated that EPA should be flexible in designing the soil
remediation.
EPA Response: In meetings with potentially responsible parties, EPA has indicated its
willingness to be flexible in the design of the soil remediation.
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5 9 0058
APPENDIX 2
STATE CONCURRENCE LETTER
STAUFFER CHEMICAL CO. (LEMOYNE PLANT) SITE
OPERABLE UNIT 2
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»ffl-!8-S9 ffiU 10:47 UB FAX NO. . 334 S79 3050 ,.«
59 0059
_ADEM
ALABAMA DEPARTMENT OF ENVIRONMENTAL MANAGEMENT
t*MiO»*ce>eK3Dm» • 17C1 COMB. W. 1- PngN>on own 9no»aEOS
MONTGOMERY, ALABAMA 36130-1463
JMKSW.WMH wwwju»unrATEJU_in DOHSCGCLIUN
m* t-« ,««o 034)271-7700 a*****
March 18, 1999
Ms. Annie M. Godfrey ^/^
Remedial Project Manager ""* a7MC6°
South Site Management Branch
U.S. Environmental Protection Agency E*
Region 4
Atlanta Federal Center I
61 Forsyth Street, SW s
Atlanta, GA 30303-3104 j
Re: Draft Record of Decision t
Stauffer LeMoyne Site. Operable Unit 2 f
Axis, Alabama I
Dear Ms. Godfrey: j
t
The Alabama Department of Environmental Management (AJDEM) has reviewed the I
referenced Draft Record of Decision. Based on our review, we concur with the Draft [
Record of Decision. [
Tf there are questions regarding this matter, please contact Mr. Keith West of the f
Industrial Facilities Section at (334) 271-7754. {
Sincerely, ji
f
•^- -—- m • •• - _ _ _ _ •— — — m^- ;.
Wm.Gei»IdHirdy, Chief /( j;
Land Division
i
i
WGH/KNW/scm:L:AkzoOU-2DniftROD (3-18-99) j
File: Akzo/CGRCLA/Rod Contspondence {
F
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