United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R04-93/133
December 1992
&EPA Superfund
Record of Decision:
Redwing Carriers/Saraland,
AL
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50272-101
REPORT DOCUMENTATION
PAGE
1. REPORT NO.
EPA/ROD/R04-93/133
3. Recipient's Accession No.
Title and Subtitle
SUPERFUND RECORD OF DECISION
Redwing Carriers/Saraland, AL
First Remedial Action - Final
5. Report Date
12/15/92
7. Author(s)
8. Performing Organization Rept. No.
9. Performing Organization Name and Address
10 Project Taskwork Unit No.
11. Contraet(C) or Grant(G) No.
(C)
(0)
12. Sponsoring Organization Name and Address
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report & Period Covered
800/800
14.
15. Supplementary Notes
PB94-964030
16. Abstract (Limit: 200 words)
The 5.1-acre Redwing Carriers/Saraland site is a former trucking terminal and current
apartment complex located in Saraland, Mobile County, Alabama. Land use in the area is
predominantly residential, with wetlands and woodlands situated near the site, and
three layers of hydrogeologic units, including an alluvial and surficial aquifer,
beneath the site. The estimated 160 people who reside onsite in the Saraland Apartment
complex use wells located to the north of the site to obtain their drinking water
supply, and although not currently utilized, the alluvial and surficial aquifers are a
potential source of drinking water. There are one grass-covered and two concrete-lined
drainage ditches onsite that eventually empty into the Norton Creek. From 1961 to
1971, Redwing Carriers operated a trucking company that transported substances such as
asphalt, diesel fuel, chemicals, an'd pesticides from local plants and that used the
site as a terminal for cleanup, repairing, and parking the fleet of trucks. Sometimes
during the cleanup process, untreated substances were released sometimes directly into
the ground. Many of the contaminants likely were diluted and washed away during storm
events; however, many of them adhered to the asphalt, which was deposited later across
the property during maintenance operations. In 1971, Redwing Carriers sold the
property, which was converted into an apartment complex. In 1984, the State
(See Attached Page)
17. Document Analysis a. Descriptors
Record of Decision - Redwing Carriers/Saraland, AL
First Remedial Action - Final
Contaminated Media: soil, sediment, debris, sludge, gw
Key Contaminants: VOCs (benzene), metals (chromium)
b. Identifiers/Open-Ended Terms
c. COSATI Field/Group
18. Availability Statement
19. Security Class (This Report)
None
20. Security Class (This Page)
None .
21. No. of Pages
102
22. Price
(See ANSI-Z39.18)
See Instructions on Rtvtrse
OPTIONAL FORM 272 (4-77)
(Formerly NTJS-35)
Department of Commerce
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EPA/ROD/R04-93/133
Redwing Carriers/Saraland, AL
First Remedial Action - Final
Abstract (Continued)
investigated complaints about a tar-like sludge oozing to the surface at numerous
locations. In 1985, EPA studies detected high concentrations of 1,2,4trichlorobenzene
and naphthalene in the soil and in leachate coming from the sludge, which has been related
to onsite ground water contamination. Subsequently, EPA required Redwing to remove any
visible sludge detected on the surface of the site. This ROD addresses the first and final
remedial action for the contaminated source material and ground.water affecting the
surficial and alluvial aquifers as a drinking water source. The primary contaminants of
concern affecting the soil, sediment, debris, sludge, and ground water are VOCs, including
benzene; and metals, including chromium.
The selected remedial action for this site includes temporarily relocating onsite
residents during excavation; removing buildings or onsite structures as needed to
facilitate excavation; excavating contaminated soil, sediment, and sludge until the
remaining source material achieves excavation levels; staging and temporarily storing the
excavated material onsite; treating the surface soil, sediment, and sludge offsite using
thermal treatment, if necessary; dewatering and solidifying the subsurface soil offsite,
if necessary, before disposing of the residuals in an offsite landfill; analyzing,
treating, and discharging the water from the dewatering process in an appropriate manner;
removing, sorting, and treating offsite, if necessary, all contaminated debris, including
sidewalk slabs and pavement areas; backfilling excavated areas with clean material;
extracting approximately 12,000,000 gallons of contaminated ground water from the
surficial aquifer using extraction wells and french drains and treating it onsite using
biological treatment and sand/activated carbon filtration, with a supplemental treatment
step, if necessary, to remove contaminants not affected by biotreatment; discharging the
treated ground water offsite to a POTW or onsite in nearby surface water; disposing of
residual sludge and spent carbon offsite in an approved facility; allowing for natural
attenuation of the alluvial ground water; and monitoring the surface soil, sludge seeps,
and ground water in the alluvial aquifer to monitor the riatural attenuation process. The
estimated present worth cost for this remedial action is $7,002,562, which includes an
estimated present worth O&M cost of $518,000.
PERFORMANCE STANDARDS OR GOALS:
Soil, sediment, and sludge cleanup goals and excavation levels are based on a human health
risk from inhalation or ingestion and ground water protection with a cleanup level of 15
ug/1 for lead. Chemical-specific goals include acetone 36 ug/kg; aldrin 4 ug/kg; alpha-BHC
0.5 ug/kg; benzo(a)anthracene 1,025 ug/kg; benzo(a)pyrene 94.9 ug/kg; benzo(b)fluoranthene
540 ug/kg; carbon tetrachloride 9,590 ug/kg; chloroform 70 ug/kg; chromium 47,000 ug/kg;
chrysene 362 ug/kg; 4,4-DDT 566 ug/kg; dieldrin 0.1 ug/kg; gamma-BHC 3.2 ug/kg; methylene
chloride 0.6 ug/kg; nickel 30,000 ug/kg; vanadium 156,000 ug/kg; and vernolate 55 ug/kg.
Ground water cleanup goals are based on SDWA MCLs. Chemical-specific ground water cleanup
goals include acetone 1,120 ug/1; aldrin 0.00317 ug/1; alpha-BHC 0.00855 ug/1; beryllium 4
ug/1; bis(2-ethylhexyl)phthalate 6 ug/1; carbon disulfide 47.6 ug/1; chloroform 100 ug/1;
chromium 50 ug/1; 4,4-DDT 0.158 ug/1; dieldrin 0.00337 ug/1; gamma-BHC 0.2 ug/1; methylene
chloride 5 ug/1; nickel 100 ug/1; vanadium 78.1 ug/1; and vernolate 11.2 ug/1.
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RECORD OF DECISION
REDWING CARRIERS, INC. (SARALAND)
NPL SITE
DECEMBER 15, 1992
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THE DECLARATION
Site Name and Location
The Redwing Carriers, Inc. (Saraland) Site (Redwing Site) is
located in Mobile County, Alabama in the corporate limits of the
City of Saraland. The 5.1 acre site is about eleven miles north of
Mobile, Alabama. The Redwing Site is bounded to the east by U.S.
Highway 43 and a skating rink. On the south it is bounded by a
United Gas Pipe Line easement. A residential development is south
of the pipe line easement. The Redwing Site is bounded on the
north by a trailer park, and on the west by an undeveloped lot.
Statement of Basis and Purpose
This decision document presents the selected remedial action for
the Redwing Site in Saraland, Mobile County, Alabama, which was
chosen in accordance with the Comprehensive Environmental Response
Compensation and Liability Act (CERCLA),. as amended by the
Superfund Amendments and Reauthorization Act (SARA), and, to the
extent practicable, the National Oil and Hazardous Substances
Polluticn Contingency Plan (NCP). This decision is based on the
administrative record for this site.
The State of Alabama concurs with the selected remedy.
Assessment of the Site
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of Deqision (ROD) , may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
Description of the Selected Remedy
The Major components of the remedy are:
Excavation of sludge, sediments, and contaminated soils.
Off-site treatment/disposal of contaminated soils, sediments
and sludge.
Regrading and backfill of excavations using clean, compacted
fill material.
Temporary and possibly permanent relocation of residents with
the potential demolition of selected apartment units.
On-site treatment of contaminated groundwater in the surficial
aquifer. Monitoring and possible withdrawal and treatment of
groundwater in the alluvial aquifer. Treated groundwater will
be discharged to a Publicly Owned Treatment Works (POTW), or
if unavailable, to a nearby surface water body.
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SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
REDWING CARRIERS, INC. (SARALAND)
SARALAND, ALABAMA
Prepared By
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION IV
ATLANTA, GEORGIA
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THE DECLARATION
Site Name and Location
The Redwing Carriers, Inc. (Saraland) Site (Redwing Site) is
located in Mobile County, Alabama in the corporate limits of the
City of Saraland. The 5.1 acre site is about eleven miles north of
Mobile, Alabama. The Redwing Site is bounded to the east by U.S.
Highway 43 and a skating rink. On the south it is bounded by a
United Gas Pipe Line easement. A residential development is south
of the pipe line easement. The Redwing Site is bounded on the
north by a trailer park, and on the west by an undeveloped lot.
Statement of Basis and Purpose
This decision document presents the selected remedial action for
the Redwing Site in Saraland, Mobile County, Alabama, which was
chosen in accordance with the Comprehensive Environmental Response
Compensation and Liability . Act (CERCLA) , . as amended by the
Superfund Amendments and Reauthorization Act (SARA), and, to the
extent practicable, the National Oil and Hazardous Substances
Polluticn Contingency Plan (NCP). This decision is based on the
administrative record for this site.
The State of Alabama concurs with the selected remedy.
Assessment of the Site
Actual or threatened releases of hazardous substances from this
site, if not addressed by implementing the response action selected
in this Record of Deqision (ROD) , may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
Description of the Selected Remedy
The Major components of the remedy are:
Excavation of sludge, sediments, and contaminated soils.
Off-site treatment/disposal of contaminated soils, sediments
and sludge.
. Regrading and backfill of excavations using clean, compacted
fill material.
Temporary and possibly permanent relocation of residents with
the potential demolition of selected apartment units.
On-site treatment of contaminated groundwater in the surficial
aquifer. Monitoring and possible withdrawal and treatment of
groundwater in the alluvial aquifer. Treated groundwater will
be discharged to a Publicly Owned Treatment Works (POTW), or
if unavailable, to a nearby surface water body.
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This remedy is the only and final remedial action for the site.
The function of this remedy is to reduce the risks associated with
exposure to contaminated soils, sediments, and ground water.
The selected remedy will:
1. Prevent migration of contaminated groundwater.
2. Prevent human exposure to contaminated soils, sediments and
sludge.
3. Permanently reduce the toxicity of the harmful constituents in
all media.
4. Prevent migration of site contaminants via drainage pathways.
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 to the remedial
action, and is cost-effective. However, because treatment of the
principal threats of the site was not found to be practicable, this
remedy does not satisfy the statutory preference for treatment as
a principal element.
Because this remedy will result in hazardous substances remaining
on-site above health-based levels, a review will be conducted
within five years after commencement of remedial action to ensure
that the remedy continues to provide adequate protection of human
health and the environment.
Patrick M. Tobin Date
Acting Regional Administrator
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TABLE OF CONTENTS
1.0 SITE NAME, LOCATION AND DESCRIPTION 1
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 5
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION 5
4.0 SCOPE AND ROLE OF RESPONSE ACTION 7
5.0 SUMMARY OF SITE CHARACTERISTICS 8
5.1 SITE GEOLOGY 10
5.2 SITE HYDROGEOLOGY 10
5.3 AREA DRINKING WATER SOURCES 11
5.4 SUMMARY OF SITE CONTAMINATION 11
5.4.1 CHEMICALS DETECTED DURING THE SITE INVESTIGATION 12
5.4.2 CHEMICALS DETECTED IN GROUNDWATER 12
5.4.3 SURFACE WATER PATHWAY INVESTIGATION 12
5.4.4 AIR PATHWAY INVESTIGATION 24
5.5 FATE AND TRANSPORT 24
5.6 SOURCE AREAS OF CONTAMINATION 28
6.0 SUMMARY OF SITE RISKS 28
6.1 CONTAMINANTS OF CONCERN 32
6.2 EXPOSURE ASSESSMENT 32
6.2.1 EXPOSURE PATHWAYS 33
6.3 TOXICITY ASSESSMENT: DOSE RESPONSE EVALUATION 46
6.4 RISK CHARACTERIZATION 52
6.5 UNCERTAINTY ANALYSIS 53
6.6 HUMAN HEALTH SUMMARY 56
6.7 ENVIRONMENTAL EVALUATION 56
6.7.1 UNCERTAINTY ANALYSIS 57
6.8 RISK ASSESSMENT SUMMARY 57
6.9 CHEMICALS OF CONCERN AND CLEANUP LEVELS 53
6.10 CONCLUSION 58
7.0 DESCRIPTION OF ALTERNATIVES 61
7.1 ALTERNATIVE No. 1 61
7.2 ALTERNATIVE No. 2 61
7.3 ALTERNATIVE No. 3 62
7.4 ALTERNATIVE No. 4 63
7.5 ALTERNATIVE No. 5 64
7.6 ALTERNATIVE No 6 64
7.7 ARARS AND TBCS 66
8.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 70
8.1 THRESHOLD CRITERIA 72
8.2 PRIMARY BALANCING CRITERIA 73
8.3 MODIFYING CRITERIA 74
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9.0 THE SELECTED REMEDY 15
10.0 STATUTORY DETERMINATIONS g-,
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES 81
APPENDIX A i
APPENDIX B
11
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LIST OF TABLES
Table Page
TABLE I - GEOLOGICAL STRATA 10
TABLE 2A - RESULTS FROM ORGANIC CHEMICAL ANALYSIS OF SLUDGE ... 14
TABLE 2B - RESULTS FROM INORGANIC CHEMICAL ANALYSIS OF BLACK SLUDGE
MATERIAL 16
TABLE 3 - REDWING SITE: SUMMARY OF CHEMICALS DETECTED DURING
REMEDIAL INVESTIGATION 17
TABLE 4 - REDWING SITE: SUMMARY OF ANALYSIS OF THE ALLUVIAL AQUIFER 23
TABLE 5 - REDWING SITE: ORGANIC AND INORGANIC CONSTITUENTS
DETECTED IN DITCH SEDIMENTS 25
TABLE 6 - AREAS AND VOLUME ESTIMATES FOR SOURCE MATERIAL (INCLUDES
SLUDGE) 26
TABLE 7A - CHEMICALS OF POTENTIAL CONCERN FOR SOILS, DITCH,
SEDIMENTS, AND TAR-LIKE MATERIAL (SLUDGE) 33
TABLE 7B - CHEMICALS OF POTENTIAL CONCERN IN GROUNDWATER 34
TABLE 8A - SURFACE SOIL AND SEDIMENTS RME CONCENTRATIONS 36
TABLE 8B - GROUNDWATER RME CONCENTRATIONS 36
TABLE 9 - EXPOSURE ASSUMPTIONS FOR U/BK MODEL 39
TABLE 10 - SUMMARY OF USEPA ASSUMPTIONS 40
TABLE 11 - SUMMARY OF NON-USEPA ASSUMPTIONS 41
TABLE 12 - GENERIC EXPOSURE ASSUMPTIONS 42
TABLE 13 - SPECIFIC EXPOSURE SCENARIO ASSUMPTIONS FOR THE RME
RECEPTOR 43
TABLE 14 - REFERENCE DOSES, CONCENTRATIONS, AND CANCER SLOPE FACTORS 47
TABLE 15 - TOXICITY EQUIVALENCY FACTORS (TEFs) FOR POLYNUCLEAR
AROMATIC HYDROCARBONS (PAHs) 52
TABLE 16 - SUMMARY OF PATHWAY SPECIFIC CARCINOGENIC RISKS .... 54
TABLE 17 - SUMMARY OF PATHWAY SPECIFIC TOTAL HAZARD INDICES (NON-
CARCINOGENIC RISKS) 55
111
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TABLE 18 - CLEANUP LEVELS FOR SUBSURFACE SOIL 58
TABLE 19 - CLEANUP LEVELS FOR SURFACE SOIL AND SEDIMENTS 59
TABLE 20 - CLEANUP LEVELS FOR GROUNDWATER 60
TABLE 21A - ACTION-SPECIFIC FEDERAL ARARS 67
TABLE 2IB - CHEMICAL-SPECIFIC FEDERAL ARARS 68
TABLE 21C - STATE OF ALABAMA ARARS 69
TABLE 22A - SURFACE SOIL AND SEDIMENT EXCAVATION LEVELS 76
TABLE 22B - SUBSURFACE SOIL EXCAVATION LEVELS 77
IV
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LIST OF FIGURES
Figure
FIGURE 1 - SITE LOCATION
FIGURE 2 - AREA LAYOUT
SITE LAYOUT
OLD TERMINAL LAYOUT
LOCATION OF SOURCE AREAS
CURRENT SITE PROPERTY AND CONTAINMENT LEVEE
SOURCE AREAS
FIGURE 3 -
FIGURE 4 -
FIGURE 5 -
FIGURE 6 -
FIGURE 7 -
FIGURE 8 .- 'DEPTHS OF SLUDGE (TAR-LIKE MATERIAL)
Paae
2
3
4
6
9
13
29
30
v
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Decision Summary
Record of Decision
Redwing Carriers Inc. (Saraland)
Saraland, Alabama
1.0 . SITE NAME, LOCATION AND DESCRIPTION
The Redwing Carriers, Inc. (Saraland) Site ("Redwing Site")
comprises 5.1 acres and is located at 527 U.S. 43 in the City of
Saraland, Mobile County, Alabama. Currently, thirteen (13)
buildings which comprise the office and resident living units of
the Saraland Apartment complex are built on the Redwing Site.
The property is bounded to the north by Cook's Mobile Home Park
(containing approximately 53 mobile homes), to the south by
private residences on Craig Drive, to the west by a wooded area
and private residences on Pierce Street, and to the east by. an
indoor roller skating rink and U.S. Highway 43. Figure 1 shows
the location of the Redwing Site.
Concrete sidewalks are between and around the apartment buildings
and along the north side of the office building. A paved drive
and parking area surrounds the buildings' units and provides
access from U.S. Highway 43 east of the complex. Two concrete
lined drainage ditches run parallel to the southern and eastern
property lines of the apartment complex. The southern ditch
converges with the eastern ditch at the southeast corner of the
Redwing Site. About 220 feet north of the southeast corner, the
eastern ditch turns east and connects to a drainage ditch running
parallel with U.S. Highway 43 at the entrance to the complex. A
third drainage ditch runs along the northern property line. This
ditch is unlined, but has a grass cover. This northern ditch
also joins with the Highway 43 drainage ditch located at the
complex entrance. A United Gas Pipe Line easement also parallels
the northern side of this ditch. In the playground of the
apartment complex are a slide and swing used by children.
Storm water runoff drains into ditches on the north, south and
east borders of the property. This ditch system empties into a "
drainage ditch parallel to Highway 43 and leads to Norton Creek
approximately 1/2 mile from the Redwing Site. Wetlands are
located within a 3 mile radius.
On-site Demographics
The Redwing Site's 60-unit apartment complex houses approximately
160 residents. Eighty to ninety of the residents are
preschool-age or elementary school-age children who frequently
play in the yard surrounding the apartments. Figures 2 and 3 are
site maps which show the current layout of the property.
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The WCM GROUP. Inc. -
FIGURE - 1
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the WCM GROUP. Inc.
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2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
From 1961 to 1971, Redwing Carriers, Inc. (Redwing), a trucking
company, used the Redwing Site as a terminal for cleaning,
repairing and parking its fleet of trucks. The firm transported
a variety of substances, including asphalt, diesel fuel,
chemicals and pesticides from local plants along U.S. Highway 43
North. During cleaning, untreated substances were released to
the ground. Figure 4 depicts the general condition of the
Redwing Site property layout during Redwing's operations.
In 1971 Redwing sold the property to Harrington Inc. which' in
turn sold the property to Apartments, Inc. on December 22, 1971.
On March 26, 1973, Apartments Inc. sold the property to Saraland
Apartments Ltd. The Saraland Apartments were built on the
Redwing Site in 1973.
In 1984, The Alabama Department of Environmental Management
(ADEM) investigated residents' complaints about a tar-like sludge
oozing to the surface at numerous locations. In 1985, EPA
conducted initial studies in which high concentrations of
1,2,4-trichlorobenzene and naphthalene were detected in the soil
and in leachate coming from the sludge.
EPA sent notice letters to potentially responsible parties (PRPs)
in 1985. EPA entered into an Administrative Order on Consent
(AOC) on July 8, 1985 with Redwing. Under the order, Redwing was
required and continues to periodically inspect the site and
remove any visible sludge on the surface.
The Redwing Site was proposed for listing on the National
Priorities List (NPL) in 1988 and finalized in February 1990. In
June 1990, Redwing Carriers Inc. entered into an Administrative
Order on Consent with EPA to conduct the Remedial
Investigation/Feasibility Study (RI/FS) to determine the nature
and extent of contamination at the site, to evaluate the
associated risks, and to evaluate alternatives for eliminating
those threats. Redwing, under EPA's oversight, began field
activities for the first phase of the remedial investigation in
January 1991. The RI/FS was completed in July of 1992.
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
All basic requirements for public participation under CERCLA
sections 113Ck)(2)(B)(i-v) and 117 were met in the remedy
selection process. Because the local community has been very
interested and involved in the Redwing Site status during the
removal and the remedial activities at this site, community
relations activities remained an important aspect throughout the
RI/FS process.
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3
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The community relations program at the Redwing Site was designed
to maintain communication between the residents in the affected
community and the government agencies conducting remedial
activities at the Redwing Site. Frequent communication with on-
site residents and local officials has been maintained as a
priority. Special attention has been directed toward keeping the
community informed of all study results. Meetings were held with
Saraland city officials and EPA staff prior to the initiation of
the RI/FS. Prior to approval of the RI/FS Workplan, EPA
officials met with the community at an availability session in
December 1990 to inform residents of EPA's intentions and to
obtain input concerning sampling locations and health and safety
procedures.
Once the first phase of the RI/FS was complete, EPA met with the
community again in August 1991 to present the Preliminary Site
Characterization Summary which detailed the results of the first
phase of the investigation. EPA also discussed the rationale for
the subsequent sampling investigation, Phase II. On August 11,
1992 after the finalization of the Remedial Investigation Report
and the completion of the Draft Feasibility Study, EPA presented
its preferred remedy for the Redwing Site during a public meeting
at the Saraland Civic Center, 731 Mae Street, Saraland, Alabama.
The 30-day public comment period began on August 1, 1992 and was
extended through September 29, 1992 pursuant to requests from the
public. A copy of the Administrative Record upon which the
remedy was based, is lo'cated at the Saraland Public Library at
111 Saraland Loop, Saraland Alabama, 36571 and extra copies of
the study were provided to a community group interested in
commenting on the proposed plan. EPA's responses to comments
which were received during the comment period are contained in
Appendix A.
4.0 SCOPE AND ROLE OF RESPONSE ACTION
This remedy is the final remedial action for the site. The
function of this .remedy is to reduce the risks associated with
exposure to contaminated soils, sediments, ground water and
sludge.
The selected remedial alternative will address four conditions
which pose a threat to human health and the environment:
Contaminated aroundwater in the surficial and alluvial aquifers
(may potentially impact drinking water supplies).
Ditch sediments along the northern, eastern and southern
boundaries of the apartment complex property (may pose a direct
contact threat to the public health).
Sludge in the upper five feet of on-site soils (presents a
7
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continuing direct contact threat to the public health).
Sludge and contaminated subsurface soils (present a continuing
source of contamination to the surficial aquifer).
Groundwater at the Redwing Site has been contaminated by the
sludge and contaminated subsurface soils. Figure 5 shows the
areas where the sludge/contaminated soil have been encountered.
These areas correspond to the locations where the highest
concentrations of contamination has been found in the surficial
aquifer. This is the principal threat posed by conditions at the
site.
Pathways of exposure include:
Ingestion of contaminated soil, sediments, and sludge
Denr.-.-". contact with contaminated soil/sediments/sludge and
potential absorption of contaminants
Ingestion of contaminated groundwater
Inhalation of vapors from volatile constituents contained in
the contaminated media.
Migration of site related contaminants to off-site areas via
drainage pathways.
The major components of the remedy are:
Excavation of sludge, contaminated soils and sediments.
Off-site materials treatment/disposal.
Receding and backfill of excavations using clean compacted
fill material.
Temporary and possibly permanent relocation of residents with
the potential demolition of selected apartment units.
On-site treatment of contaminated groundwater in the surficial
aquifer. Monitoring, possible withdrawal and treatment of
groundwater in the alluvial aquifer. Treated groundwater will
be discharged to a Publicly Owned Treatment Works (POTW), or if
unavailable, to a nearby surface water body.
5.0 SUMMARY OF SITE CHARACTERISTICS
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FIGURE - 5
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5.1
SITE GEOLOGY
The Redwing Site geology was determined from regional geological
information and from site-specific data gathered during the
Remedial Investigation. The Redwing Sit^ is situated on fill
soils overlying He . ocene and possibly Pleistocene alluvium. Four
generalized strat:. ..raphic units have been defined as in Table I
below.
TABLE 1 - GEOLOGICAL STRATA
Stratum
I
II
III
IV
Approximate
Depth Range
(feet)
0.0 - 6.0
1.0 - 12.5
4.0 - 29.5
8.0 - 40.0 +
Description
Fill: Clayey to silty sand.
Clayey to silty sand with
sandy clay and silt lenses.
Clay and sandy to silty clay
with few silty sand lenses.
Sand and silty to clayey sand
with occasional clay lenses.
Details regarding the regional and site geology are contained in
the RI Report.
5.2
SITE HYDROGEOLOGY
The primary aquifer underlying the Redwing Site is a group of
alluvial and terrace deposits ranging in thickness from a thin
veneer to more than 150 feet and consisting of fine to
coarse-grained sands, gravel, silts, sandy clay and organic
material. The groundwater in the vicinity of the Redwing Site is
approximately 10 feet below land surface. The Redwing Site is
underlain by strata that comprise the Alluvial aquifer of Mobile
County. Three distinct hydrogeologic units were identified from
four strata underlying the Redwing Site. The designations
assigned to these three units are as follows: (1) the Surficial
Aquifer (upper sands); (2) a Low Permeability Unit and (3) the
Alluvial Aquifer (lower sands). Groundwater in the aquifers
beneath the Redwing Site have been classified as Class IIB for
the surficial groundwater and Class IIA for the alluvial aquifer.
Class IIB groundwater is a potential drinking water source
although the groundwater may not be currently used as such.
Class IIA groundwater is a current source of drinking water.
10
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Watertable elevations indicate that groundwater flow within the
Surficial Aquifer is toward the south. This southward flow
coincides with the southward slope of the underlying Stratum III
surface.
The low permeability hydrogeological unit is represented by
Stratum III as was described in Table 1.
The third hydrogeologic unit encountered at the Redwing Site is
defined by the lower sands designated as Stratum IV. Stratum IV
has been designated the Alluvial Aquifer Unit. Groundwater in
the Alluvial Aquifer is generally first encountered at.depths 11
feet to 19 feet. Groundwater flow in the Alluvial Aquifer is in
a westerly direction. This flow direction is almost
perpendicular to the watertable groundwater flow in the surficial
Aquifer.
5.3 AREA DRINKING WATER SOURCES
Drinking water'for residents of Saraland is supplied by the City
of Saraland Water Department, which obtains its water supply from
wells located north of the Redwing Site. These three wells are
located between 5000 and 7500 feet north of the Redwing Site.
The depths range from 95 feet to 124 feet below ground surface.
An additional well is located about 1400 feet southeast of the
Redwing Site and extends to a depth of 98 feet. A well inventory
survey was conducted to identify private wells within a one mile
radius of the Redwing Site and identified 124 private wells in
the area. Seventeen of the wells are currently being used. Two
of the wells have their last documented use recorded as 1987.
The uses range from drinking water to water for gardening. The
wells range in depth from 15 to 140 feet. The complete results of
the survey are contained in the Remedial Investigation report.
5.4 SUMMARY OF SITE CONTAMINATION
The Remedial Investigation was initiated in December 1990. The
RI sampling, conducted in 1991 and 1992, focused on areas related
to former terminal operations. Figure 6 shows a containment
levee (thought to be the residuals disposal area) overlain by the
current site features. During the truck washing operations,
chemical residue and other contaminants were released from the
trucks onto the ground and into the drainage ditches and levee
areas on the property. Many of the contaminants were likely
diluted and washed away during storm events, however, many of
them adhered to the asphalt which was also deposited across the
property during maintenance operations. The asphalt was
contained primarily in the levee area with overflow going to the
ditches. Many of the chemicals from the truck washing affixed
themselves to the asphalt. This resulted in the sludge that we
11
-------
FIGURE - 6
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-------
currently encounter at the Redwing Site. Tables 2A and 2B
contain the results from analysis of the sludge. The sludge is
present at the Redwing Site in two forms: (1) surface seeps at
194 locations since 1985 (see Figures 5 and 6), and (2) sludge
mixed with soil found in 15 samples across the Redwing Site.
There is a direct relationship between constituents found in the
soil and in the surficial groundwater. '
5,4.1 CHEMICALS DETECTED DURING THE SITE INVESTIGATION
During the investigation, 39 soil borings were collected with a
total of 123 separate soil samples being analyzed. The
substances found most frequently at concentrations above cleanup
levels fall into three major categories: 1) pesticides and
herbicides; 2) Volatile organic compounds (VOCs) and 3)
Polycyclic Aromatic Hydrocarbons (PAHs).
These substances were found in soils, ditch sediments, and
groundwater across the Redwing Site. The highest levels of
contamination were detected in the southern and eastern portions
(the location of the former containment levee used by Redwing)
-*and across areas of former terminal operations. Inorganic
substances, which may occur in nature in significant levels, were
also detected in soils, sludge and groundwater.
-5.4.2 CHEMICALS DETECTED IN GROUNDWATER
Substances moving from soil and the sludge have contaminated
groundwater in the surficial, or shallow, aquifer. Highest
.groundwater contaminant concentrations are under the eastern half
of the Redwing Site, but the upper aquifer has been affected
under most of the Redwing Site. Limited movement of contaminants
to the alluvial (lower) aquifer has occurred, but at much lower
levels.
Table 3 illustrates the migration of contaminants from "the source
areas to the surficial groundwater and alluvial sands. The
groundwater in the alluvial aquifer was found to be contaminated
in limited areas with some site related constituents. Table 4
illustrates the result of the alluvial aquifer sampling.
5.4.3 SURFACE WATER PATHWAY INVESTIGATION
Storm water which contacts surface soils, and sludge that has
seeped to the surface, drains into on-site ditches resulting in a
possible exposure pathway. The northern ditch is unlined but
covered with grass. The southern and eastern ditches are now
concrete-lined but were unlined when Redwing operated at the
Redwing Site. Therefore, the study of the ditches extended to
13
-------
TABLE 2A - RESULTS FROM ORGANIC CHEMICAL ANALYSIS OF SLUDGE
COMPOUND
1,1,1 TRICHLOROETHANE
1,2,4 -TRICHLOROBEN2ENE
2-BUTANONE (MEK)
2 -CYCLOHEXEN- 1 -OL
2-HEPTANONE
2-HEXANONE
2 -METHYLNAPHTHALENE
2-PENTANONE, 4-HYDROXY-4-METHYL
2-PROPANOL
4 -METHYL - 2 - PENTANOl ;Z
4,4' -DDD
4, 4 '-DDE
4, 4 '-DDT
ACENAPHTHENE
ACETONE
ALDRIN
ALPHA-BHC
ALPHA-CHLORDANE
ANTHRACENE
BENZENE
B El -:,: . A ) ANTHRACENE
BENZO (A) PYRENE
BENZO (B) FLUORANTHENE
BENZO (K) FLUORANTHENE
BENZO- ( G , H , I ) PERYLENE
BETA-BHC
BIS ( 2-ETHYLHEXYL) PHTHALATE
BUTYLATE
CACARBAMOTHOIC ACID.DIPROYL
CARBON DISULFIDE
CHLOROFORM
NO OF TIMES
DETECTED
1
2
3
1
1
2
3
8
2
1
3
1
4
2
7
1
1
12
4
3
5
3
5
1
2
1
4
8
1
3
1
RANGE OF CONCENTRATIONS DETECTED
tig /kg
3
4,000 - 18,000
13 - 120
180
48
11 - 27
2,500 - 5,200
1,900 - 100,000
12-36
15
0.1 - 6.8
0.29
0.48 - 11
2,600 - 4,600
54 - 610
0.86
1.1
762 - 19,100
200 - 7,300
4-48
160 - 7,2C.
920 - 3,200
280 - 7,200
1,700
610 - 880
6.4
58 - 200
450 - 51,000
4,900
5-24
4
14
-------
TABLE 2A - RESULTS FROM ORGANIC CHEMICAL ANALYSIS OF SLUDGE
COMPOUND
CHRYSENE
CYCLOATE
CYCLOHEXANE, DICHLORO
CYCLOHEXANOL , CHLORO
DELTA-BHC
DIBENZOFURAN
DIELDRIN
ENDRIN
ENDRIN KETONE
EPTC
ETHYLBENZENE
FLUORANTHENE
FLUORENE
GAMMA-BHC (LINDANE)
HEPTACHLOR EPOXIDE
INDENO (1,2,3 -CD) PYRENE
METHOXYCHLOR
METHYLENE CHLORIDE '
MOLINATE
NAPHTHALENE
NAPHTHALENE, 1 -METHYL
NAPHTHALENE ,2,3 -DIMETHYL
PEBULATE
PHENANTHRENE
PYRENE
SULFER, MOL(S8)
TOLUENE
VERNOLATE
XYLENE
NO OF TIMES
DETECTED
5
2
1
1
1
2
2
2
1
4
2
6
4
1
1
2
1
3
2
2
1
1
7
5
6
6
3
7
3
RANGE OF CONCENTRATIONS DETECTED
Hg/kg
160 - 6,000
6.6 - 10
670
1,400
0.23
2,200 - 6,800
1.1 - 3.4
3.3 - 11
17
39 - 1,900
18 - 120
200 - 23,000
2,300 - 12,000
0.12
1.7
710 - 1,300
13
5-48
18 - 21
3,900 - 13,000
9,900
5,600
25 - 9,800
850 - 33,000
ISO - 12,000
1,600 - 100,000
30 - 52
43 - 130,000
5 - 480
15
-------
TABLE 2B - RESULTS FROM INORGANIC CHEMICAL ANALYSIS OF BLACK
SLUDGE MATERIAL
CHEMICAL
ALUMINUM
ARSENIC
BARIUM
BERYLLIUM
CADMIUM
CALCIUM
CHROMIUM .: II/VI)
COBALT
COPFSR
IRON
LEAD
MAGNESIUM
MANGANESE
MERCURY
NICKEL
POTASSIUM
SELENIUM
SODIUM
VANADIUM
ZINC
NO OF TIMES
DETECTED
12
6
11
2
2
12
11
1
11
12
11
12
10
7
6
5
3
12
12
12
RANGE OF CONCENTRATIONS INORGANIC CHEMICALS
DETECTED (mg/kg)
762 - 19,100
0.71 - 3.3
9.1 - 80,9
0.39 - 0.63
2.2 - 9.5
59.1 - 27,100
2.7 - 51.9
2.7
1 - 23.7
204 - 9,150
4.2 - 316
11.1 - 361
2.1 - 372
0.15 - 1.9
3 - 30.1
199 - 1,960
0.62 - 1.6
169 - 12,900
1.8 - 30.6
2.2 - 97.7
16
-------
TABLE 3 - REDWING SITEt SUMMARY OF CHEMICALS DETECTED DURING REMEDIAL INVESTIGATION
* - INDICATES TENTATIVELY IDENTIFIED
COMPOUNDS
6 - INDICATES ORGANIC COMPOUND WHICH
WAS ALSO DETECTED IN THE ALLUVIAL
GROUNDWATER
CHEMICALS
1.1,1 TRICHLOROETHANE
1,2-CYCLOHEHANEDIOL *
1 . 2 . 4-TRICHLOROBENZENE
1,4 DICHLOROBENZENE
2(3HI-FURANONE,DIHYDRO-4,5
2-BUTANONE (MEKI
2-CYCLOHEXEN-l-OL
2-CYCLOHEXEN-l-ONE
2-HEPTANONE
2-HEXANONE
2-HEXANONE, 5-METHYL *
2-METHYLNAPHTHALEME
2-METHYLPHENOL
2-PENTANONE.4-HYDROXY 4 METHYL '
2-PROPANOL "
2,4-D
2 , 4 -DIMETHYLPHENOL
2,4,5-T
2,5 CYCLOHEXADIENE-l, 4-D10NE *
4-METIILY-2-PEHTANONE
4 METHI.YPIIF.riOL
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE VADOSE
ZONE ( 0 ' - 2 ' 1
RANGE OF
CONCENTRATIONS
DETECTED(ng/kg)
ND
NO
290 - 18,000
ND
ND
95
ND
ND
ND
4 -64
1,300 -2,200
4,300 - 4,700
ND
5.700 - 170,000
190
ND
ND
20
NO
15 - 19
IIU
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE
SATURATED ZONE
12'- 81 )
RANGE OF
CONCENTRATIONS
DETECTED(Hg/kg)
3
ND
64 - 3,000
190
ND
8 - 13
180
ND
14
5 - 29
ND
44 - 2,600
ND
1,200 - 130,000
12 - 13
9.2
ND
NO
620
8 - 27
77
RESULTS FROM
CHEMICAL ANALYSIS OF
SURFICIAL
GROUNDWATER
RANGE OF
CONCENTRATIONS
DETECTED IHg/1)
ND
13
ND
ND
79
12 - 72
8 - 12
4.7
ND
4-16
ND
ND
120
24
ND
14
20
9.6
20
16
12 790
RESULTS FROM
CHEMICAL ANALYSIS
OF ALLUVIAL SANDS
RANGE OF
CONCENTRATIONS
DETECTED (|lg/kg!
HD
ND
ND
ND
ND
MD
ND
ND
MD
ND
210 - 7SO
I ID
ND
3, SOO - 21,000
32 - 44
8.2
ND
3.4
no
MD
HD
17
-------
TABLE 3 - REDWING SITE: SUMMARY OF CHEMICALS DETECTED DURING REMEDIAL INVESTIGATION
* - INDICATES TENTATIVELY IDENTIFIED
COMPOUNDS
6 - INDICATES ORGANIC COMPOUND WHICH
WAS ALSO DETECTED IN THE ALLUVIAL
GROUNDWATER
CHEMICALS
4. t '-ODD
t, 4 '-DDE
4, 4 '-DDT "
ACENAPHTHENE
ACETONE b
ALDRIN
ALPHA- BHC
ALPHA-CHLORDANE
ALUMINUM
ANTHRACENE
ARSENIC
BARIUM
BENZENE
BENZO ( A ) ANTHRACENE
BENZOIAIPYRENE
BENZO ( B ) FLUORANTHENE
BENZO ( K 1 FLUORANTHENE
BENZO- (G,H, IIPERYLENE
BENZOIC ACID '
BENZOIC ACID-DICHLORO *
BERYLLIUM
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE VADOSE
ZONE ( 0 ' - 2 ' 1
RANGE OF
CONCENTRATIONS
DETECTED |(lg/ kg)
12 - 65
2 - 5.8
16 - 74
2,700
3 - 230
0.36 - 10
1.1 - 4.7
4.5 - 14
(1,850 - 19, 100)E'
200 - 2,000
1,400 - 3,600
10,800 - 80,900
4
1,000 - 1,800
920 -1,200
3000
1,700
100 - 610
ND
ND
610
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE
SATURATED ZONE
(2'- 8')
RANGE OF
CONCENTRATIONS
DETECTEDIHg/kgl
.36 - 17
3.8 - 5.8
1 - 25
170 - 1,400
30 - 270
0.86 - 15
2 - 3.2
6.9 - 19
(1,740 - 10,400)E'
240 - 2,100
1,300 - 3,500
9, 100 - 56,200
4
6,900
ND
7,400
ND
ND
ND
ND
260 - 300
RESULTS FROM
CHEMICAL ANALYSIS OF
SURFIC1AL
GROUNDWATER
RANGE OF
CONCENTRATIONS
DETECTED ((lg/1)
ND
ND
0.86
ND
550 - 4,400
.011 - .47
0.044 - 0.15
ND
(8.04 - 229IE'
ND
4 - 22.6
231 - 1,100
ND
ND
ND
ND
ND
ND
16 - 66
5
3.9 - 9.5
RESULTS FROM
CHEMICAL ANALYSIS
OF ALLUVIAL SANDS
RANGE OF
CONCENTRATIONS
DETECTED (pg/kgl
ND
ND
4.5
ND
25 240
2.6
ND
210 - 750
(257 - 2,430) E'
NO
(1.3 - 1.5) F.1
(5.3 - 13.1-:.
ND
ND
ND
ND
ND
ND
ND
ND
430 - 440
18
-------
TABLE 3 - REDWING SITES SUMMARY OF CHEMICALS DETECTED DURING REMEDIAL INVESTIGATION
* - INDICATES TENTATIVELY IDENTIFIED
COMPOUNDS
" - INDICATES ORGANIC COMPOUND WHICH
WAS ALSO DETECTED IN THE ALLUVIAL
GROUNDWATER
CHEMICALS
BETA - BHC
BICYCLO(2,2, DHEPTAN-2-ONE
BIS(2-ETHYLHEXYL)PHTHALATE "
BUTYLATE b
CADMIUM
CALCIUM
CARBAMOTHIOJC ACID, DIPROPYL
CARBON TETRACHLOR IDE
CARBON DISUI.FIDE
CHLOROBENZENE
CHLOROFORM
CHLOROPYRIFOS
CHROMIUM (III/VI)
CHRYSENE
CINEOLEIVANI "
COBALT
COPPER
CYANIDE
CYCLOATE b
CYCLOHEXANE(DOT) *
CYOLOHEXANECARABOXYLIC ACID *
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE VADOSE
ZONE ( 0 ' - 2 ' )
RANGE OF
CONCENTRATIONS
DETECTED (fig /kg)
6.4 - 10
ND
58 - 580
1.7 -' 30,000
2,200 - 9,500
(1,440 - 61,600)E'
4,900
110,000
5
19
100
ND
4,500 - 51,900
160 - 2,400
780 - 7,700
1,900 - 2,700
1,900 - 23,700
ND
6.6 - 10
7
HO
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE
SATURATED ZONE
<2'- 8')
RANGE OF
CONCENTRATIONS
DETECTED l(Jg/kg)
2 - 29
ND
58 - 500
2.4 - 4,900
ND
(106 - 9.490IE1
470
ND
4-9
ND
250
230
3,500 - 19,000
6,000
ND
1,500
1,200 - 27,000
1,600
3.4 - 390
ND
NO
RESULTS FROM
CHEMICAL ANALYSIS OF
SURFICIAL
GROUNDWATER
RANGE OF
CONCENTRATIONS
DETECTED
-------
TABLE 3 - REDWING SITEt SUMMARY OF CHEMICALS DETECTED DURING REMEDIAL INVESTIGATION
- INDICATES TENTATIVELY IDENTIFIED
COMPOUNDS
* - INDICATES ORGANIC COMPOUND WHICH
WAS ALSO DETECTED IN THE ALLUVIAL
GROUNDWATER
CHEMICALS
CYCLOHEXANE.DICHLORO rt
CYOLOHEXANOL.CHLORO '"
CYCLOPENTANECARBOXALDEHYDE '"
CYCLOPENTANOL.2-METHLY *
DELTA -BHC "
DI-N-BUTYL PHTHALATE
DIBENZOFURAN
DICAMBA
DICHLORPROP
DIELDRIN
DIETHYLPHTHALATE
ENDOSULFAN SULFATE
ENDOSULFAN I
ENDRIN
ENDRIN ALDEHYDE
ENDRIN KETONE
EPTC b
ETHAHONE, 1- ( 3-ETHYLOXIRANYLI
ETHYLBENZENE
FLUORANTHENE
FLIIOREtlE
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE VADOSE
ZONE 10' - 2 ' )
RANGE OF
CONCENTRATIONS
DETECTED (Jig/ kg)
ND
ND
ND
ND
ND
13
2,200
100
220
0.61 - 6.3
ND
ND
0.93
1.1 - 11
ND
2.5 - 17
5.9 - 490
ND
4 - 87
660 - 11,000
3,800 - 10.000
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE
SATURATED ZONE
(2'- 8')
RANGE OF
CONCENTRATIONS
DETECTEDIHg/kg)
200 - 850
340 - 2,500
ND
ND
.23 - IS
30
130 - 1, 100
ND
ND
1.1 - 14
390
3.8 - 19
2
1.7 - 18
3.8
3.8 - 15
1.7 - 800
480
ND
120 - 14,000
170 - 2,300
RESULTS FROM
CHEMICAL ANALYSIS OF
SURFICIAL
GROUNDWATER
RANGE OF
CONCENTRATIONS
DETECTED (flg/l)
7 - 24
13 - 140
4 - 26
230
0.04
3-4
ND
ND
ND
.012 - 1.1
ND
.02
ND
.018 - 1.5
ND
ND
.24 - 1.9
ND
ND
ND
NU
RESULTS FROM
CHEMICAL ANALYSIS
OF ALLUVIAL SANDS
RANGE OF
CONCENTRATIONS
DETECTED (|ig/kgl
ND
ND
ND
ND
ND
ND
ND
ND
ND
1.9
ND
ND
ND
5
ND
ND
ND
ND
ND
NO
ND
20
-------
TABLE 3 - REDWING SITE: SUMMARY OF CHEMICALS DETECTED DURING REMEDIAL INVESTIGATION
* - INDICATES TENTATIVELY IDENTIFIED
COMPOUNDS
* - INDICATES ORGANIC COMPOUND WHICH
WAS ALSO DETECTED IN THE ALLUVIAL,
GROIJNDWATER
CHEMICALS
GAMMA-BHC ILINDANE)
GAMMA-CIILORDANE
HEPTACHLOR
IIEPTACHLOR EPOXIDE
HEXADECANOIC ACID *
HYDROCARBON COMPOUND *
IHDENO ( 1 , 2 , 3 , -CD) PYRENE
IRON
LEAD
MAGNESIUM
MAIIOAIIKSE
MERCURY
METHOXYCHLOR
METHYLENE CHLORIDE
MOLINATE
NAPHTHALENE
NAPHTHALENE 1 -METHYL * *
NAPHTHALENE. 2. 3-DIMETHYL '
NICKEL
PEBULATE
PHENANTHREHE
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE VADOSE
ZONE ( 0 ' - 2 ' )
RANGE OF
CONCENTRATIONS
DETECTED (Hg/ kg)
2.5
2.1 - 9.9
1.4
.58 - 5.3
500
ND
710
(760 - 11, 900 IE1
11.13 - 33.4IE1
(100 - 2. 150 IE'
(100 - 2, 150 IE'
120 - 1,400
4-1
4 - 89
21
3,900
9,900
5,600
4,900 - 30, 100
1.6 - 9, HOO
B50 - 15,000
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE
SATURATED ZONE
12'- 8' )
RANGE OF
CONCENTRATIONS
DETECTED (Jig/ kg 1
.12 - 16
2 - 9.6
1 - 15
.53 - 2
ND
970
ND
(2,080 - 15,400)E'
(3.9 - 42.8IE'
(56.3 - 568) E1
(2.5 - 259IE1
130 - 1,200
.25 - 34
3 - 180
18
48 - 2, 100
ND
ND
4,700 - 22,500
7.7 - 1,300
160 - 6,500
RESULTS FROM
CHEMICAL ANALYSIS OF
SIJRFICIAL
GHOUHDWATER
RANGE OF
CONCENTRATIONS
DETECTED (Jig/ 11
.01 - 0.7
ND
0.018 - 0.51
ND
ND
ND
ND
(8.63 - 937) E'
3.4 - 162
(4.73 - 45.6IE'
(757 - 1.890IE1
ND
ND
330 -650
0.14
16
ND
36.2 - 301
28.7 - 301
0.61
HD
RESULTS FROM
CHEMICAL. ANALYSIS
OF ALLUVIAL SANDS
RANGE OF
CONCENTRATIONS
DETECTED (pg/kg)
7.7 - 7.8
ND
3.4
ND
ND
ND
ND
(385 - 3.6001E'
760 - 3,000
(40.3 - 348IE'
(3.1 - 9 . 4 ) E'
ND
ND
ND
ND
ND
ND
ND
27, 100
HD
HD
21
-------
TABLE 3 - REDWING SXTEi SUMMARY OF CHEMICALS DETECTED DURING REMEDIAL INVESTIGATION
- INDICATES TENTATIVELY IDENTIFIED
COMPOUNDS
* - INDICATES ORGANIC COMh'i'lID WHICH
WAS ALSO DETECTED IN THE ALLUVIAL
GROUNDWATER
CHEMICALS
PHENOL
PHENOL-DIMETHYL *
POTASSIUM
PYRENE
SELENIUM
SODIUM
SULFUR, MOLIS8) * b
TETRACHLOROETHANE
TOLUENE
VANADIUM
t'1 VERNOLATE
XYLENE
ZINC
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE VADOSE
ZONE ( 0 ' - 2 ' )
RANGE OF
CONCENTRATIONS
DETECTED (Jig /kg)
NO
ND
(206 - 334IE1
160 - 8,400
710 - 1,600
(37.1 - 3,600)EJ
190 - 44,000
1,600
3-46
8,400 - 49,900
2 - 26,000
5 - 990
1,340 - 97,700
RESULTS FROM
CHEMICAL ANALYSIS OF
SOILS IN THE
SATURATED ZONE
12'- 9'|
RANGE OF
CONCENTRATIONS
DETECTED (fig /kg)
ND
ND
199,000
1000 - 11,000
890
(SB. 2 - 5.4301E'
380 - 100,000
ND
30
5,700 - 31,900
49 - 8,400
5
4,300 - 207,000
RESULTS FROM
CHEMICAL ANALYSIS OF
SURFICIAL
GROUNDWATER
RANGE OF
CONCENTRATIONS
DETECTED (Hg/1)
520
61
J-.U - 25,500
ND
3.7
(37.8 - 2.370IE1
6 - 96
ND
4
16.5 - 580
1.1 - 140
ND
187 - 739
RESULTS FROM
CHEMICAL ANALYSIS
OF ALLUVIAL SANDS
RANGE OF
CONCENTRATIONS
DETECTED 1 fig /kg)
ND
ND
254,000
ND
ND
(44.6 - 89.6IE'
230 - 4000
ND
24
4,700 - 8,400
ND
ND
2,700 - 51, 100
22
-------
TABLE 4 - REDWING SITE: SUMMARY OF
CHEMICALS
1 . 3 -DICXOLANE, 2-ETHYL-4 -MET
2-PROPANOL '
4, 4 ''-DDT
ACETONE
ALUMINUM
ARSENIC
BARIUM
BERYLLIUM
BIS i 2 -ETHYLHEXYL ! PKTHALATE
BUTYLATE
CALCIUM
CAPROLACATAM *
CHLORINATED HYDROCAR30N COM? *
CHROMIUM (III/VI;
COBALT
COPPER
CYCLOATE
CYCLOHEXANE.DICHLORO
CYCLOHEXANOLCHLORO
CYCLOPENTANECARBOXALDEKYDE
DE1TA-3HC
DI-N-CCTYL PHTHALATE
E?TC
IRON
LEAD
MAGNESIUM
MANGANESE
NAPHTHALENE 1-METHYL *
NICKEL
POTASSIUM
SODIUM
SULFUR, MOLIS8)
VANADIUM
VZKNOLATE
ZINC
ANALYSIS OF THE ALLUVIAL AQUIFER
RESULTS FROM CHEMICAL ANALYSIS
OF ALLUVIAL GROUNDWATER
RANGE OF CONCENTRATIONS
DETECTED (|lg/i)
ICO
£
.01 - .08
12 - 180
6. 350 - 42,000
4 - 29.8
98.9 - 213
1.3 - 5.2
2 - 620
0.31 - 1
13, 000 - 44,800
14 - 26
4 - 6.1
28.7 - 66.3
6.5 - 33.3
18.9 - 34.9
0.15
16 - 51
180 - 260
10 - 37
.02
29
0.12
8,850 - 166,000
16.5 - 79.9
2,830 - 9,640
27C - 479
6
21.4 - 44.3
3,480 - 9,090
10,300 - 77,400
30
15.8 - 111
0.44 - 1.8
67.4 - 324
NO. OF
DETECTS
1
i
2
8
11
7
±±
3
7
2
11
2
3
11
6
8
1
4
4
3
1
^
1
11
10
11
11
1
5
8
11
1
3
4
RESULTS FROM CHEMICAL ANALYSIS
OF BACKGROUND AlLl'VIAL
GSOUNDwATEr.
RANGE OF CONCENTRATIONS
DETECTED {(ig/i!
ND
ND
ND
180
3,780
NC
93.8
ND
ND
ND
11,500
ND
ND
21.3
5.2
14.3
ND
ND
ND
ND
ND
ND
ND
7,380
9
2,400
253
ND
ND
2,140
7, 590
ND
14.5
ND
55.3
Nc . OF
_/:..:.. . j
.-
ND
.::
::D
M
V"1
''"'
_
ND
ND
i
;
N'D
N-
NI.'
ND
ND
I.'D
:::
i
i
^
1
t.;~
r-.
i
i
N3
1
N"
- INDICATES TENTATIVELY IDENTIFIED COMPOUND
23
-------
soils beneath the concrete liners. Contaminants found in the 8
ditch samples were similar to those' detected in soils'. Table 5
illustrates the contaminants found in the ditch sediments.
A ditch sample collected below the concrete liner in the eastern
ditch contained the highest number of compounds at the highest
concentrations. Lower concentrations were found in downstream
ditch areas.
Site ditches provide only temporary habitats for aquatic plants
and animals. Two water species, the arrowhead plant and
mosquitofish, were observed after heavy rain. The mosquitofish
would likely move downstream as ditch water dried up. Since
contaminants in ditch sediments can move downstream and could
have moved in the past, EPA used data from on-site ditch
sediments to predict effects on plant and animal life in
downstream surface water bodies. The analysis of these data
indicates that the highest concentrations are presently separated
from the ditch by the concrete liner and that measurable levels
are not presently moving off-site.
5.4.4 AIR PATHWAY INVESTIGATION
A sample of sludge was collected and the vapor from the headspace
a:, ilyzed at temperatures 25°C and 45°C (77 and 113 degrees
fa..renheit, respectively). Two volatiles were detected at the
high temperature and one semi volatile at the low temperature.
Additionally, air modeling -was conducted using assumptions which
were more conservative than the above headspace analysis. This
was done to predict risk that might be posed if people were
breathing those contaminants in the air. Modeling and air
monitoring results indicated that exposure, above Federal/State
standards, to chemicals in the air was not likely to occur.
5.5 FATE AND TRANSPORT
An evaluation of the potential for transport and likely fate of
compounds detected during the remedial investigation consisted of
analysis of the relationships among the various media at the
Redwing Site. This evaluation also entailed a review of the
physical and chemical data for each constituent in all
potentially affected media. To estimate concentrations for media
and locations where no samples were collected or over time frames
for which data is not available, estimates were made of
concentrations using environmental fate and transport models.
Exposure pathways for modeling were (1) a source and mechanism of
chemical release; (2) an environmental transport medium; (3) a
point of pot- -.tial exposure and (4) an exposure route. The media
evaluated foi both present and potential future exposure were (a)
groundwater (alluvial and surficial); (b) soils and seeps of
sludge; (c) air and (d) surface water and sediments.
Contaminants have been found primarily in the e~ ~ern portion of
the Redwing Site and in the location of the for: / levee. The
contaminants are affiliated with the sludge and . -.e soil that is
24
-------
TABLE 5 - REDWING SITE: ORGANIC AND INORGANIC CONSTITUENTS DETECTED IN DITCH
SEDIMENTS
- INDICATES TENTATIVELY IDENTIFIED COMPOUNDS (TICs)
» - INDICATES ORGANIC COMPOUND WHICH WAS ALSO
DETECTED IN THE ALLUVIAL GROUNDWATER
CHEMICALS
RESULTS OF ANALYSIS
FROM BACKGROUND SOILS
RANGE OF CONCENTRATIONS
DETECTED '>g/kg!
RESULTS OF ANALYSIS Fr.C-K DITCH
SEDIMENTS
RANGE OF CONCENTRATIONS
DETECTED (pig/kg1
N'c. cf
0-i-*---S
OROANICS
1 , 1-, 1 -TRICKLOROETHANE
2-S'JTANONE (MEK)
2-CYCLOHEXEN-l-OL
2 -METHYLNAPHTHALENE
2-PENTANONE.4-HYDROXY 4 -METHYL '
4, 4 '-ODD
4, 4 '-DDE
4, 4 '-DDT "
ACENAPHTHENE
ACETONE "
ALDP.IN
ALPHA-BHC
ALPKA-CHLORDANE
ANTHRACENE
3ENZO ( A i ANTHRACENE
EEN20 ( S } FL'JCRANTHENE
BETA - EHC
BIS ( 2 -ETHYLHEXYL ) PHTHALATE "
B'u'TYLATE b
CHRYSENE
CYCLOHEXANE.DICHLORO ' *
CYCLOHEXANOLCHLCRO *
DELTA-BHC *
DIBENZOFURAN
DIELDRIN
ENDOSULFAN I
ENDRIN
END?. IN KETONE
ENDRIN ALDEHYDE
ETHYL3ENZENE
ETHYNS. FL'JCP.C-'
ND
8
ND
ND
ND
ND
.47 - .61
ND
ND
5 - 67
ND
ND
.38 - 1.8
ND
180
300
ND
79 - 180
ND
93
ND
ND
ND
ND
0.57
ND
ND
ND
ND
ND
ND .
8
1? - 6£
1 * f.
-t .
2,200
9,000 - 7 £,000
0.34
0.23
0.32
2,400 - 2.7CC
33 - 160
0.67 - 200
0.16
0.67 - :;
1,300
1,300
1,30:
4.8
140 - 160
120
1,300
150
1,800
18
1,500 - 1,800
C . 16
0.93
0.52
3.9
3.9
IS
7
:
;
S
1
.
J.
)
4
^
i
;
:
1
i
i
2
^
^
i
;
:
;
^
;
;
i
^
-
25
-------
TABLE 5 - REDWING SITE: ORGANIC AND INORGANIC CONSTITUENTS DETECTED IN DITCH
SEDIMENTS
- INDICATES TENTATIVELY IDENTIFIED COMPOUNDS (TICs)
» - INDICATE-- ORGANIC COMPOUND WHICH WAS ALSO
DETECTED IN THE ALLUVIAL GROUNDWATER
CHEMICALS
FL'JORAT.'THENE
FLUOP.ENE
GAMMA-BHC (LINDANE!
GAMMA-CHLORDANE
HEPTACHLOR
HEPTACHLOR EPOXIDE
METHOXYCHLOR
METKV^ENE CHLORIDE
NAPHTHALENE
NAPTHALENE. -TRIMETHYL-
NAPHTHALENE, 2, 3 -DIMETHYL *
PEBULATE
PHENANTHRENE
PYRENE
SULFUR, MOL(S8) "
VERNOLATE
XYLENE
RESULTS OF ANALYSIS
FROM BACKGROUND SOILS
RANGE OF CONCENTRATIONS
DETECTED (Jig/kg)
310
ND
ND
.42 - 1.3
ND
ND
ND
2-10
NC
ND
ND
ND
97
240
ND
ND
ND
INORGANICS
ALUMINUM
ARSENIC
BARIUM
CALCIUM
CHROMIUM (III/VI)
COBALT
COPPER
IRON
LEAD
MAGNESIUM
MANGANESE
MERCURY
NICKEL
POTASSIUM
254 - 4,140
ND
7.6 - 42.1
38.3 - 1,350
1.4 - 8.2
8.9
1.1 - 4.2
322 - 9,520
3.8 - 9.8
28.5 - 820
1.9 - 107
ND
7
25.8 - 396
RESULTS OF ANALYSIS ~ZCV D:~CH .
SEDIMENTS i
RANGE OF CONCENTRATIONS
DETECTED (fig/kg!
4, 500 - 7,700
2,500 - 2.SOC
0.087 - 54
0.76 - 18
0.69
1.5
2.5
7-31
5,200
9, 300
13, OOC
IS - 71
8,700 - 11,000
3,300 - 4, SOO
180 - 52,000
290 - 2,600
17 - 25
No . of
Deteccs
:,
2
;
;
1
2
:
:
2
:
;.
2
n
1,350 - 10,700
1.2 - 2.8
11.5 - 32.2
338 - 6,460
4.9 - 24.3
1.8 - 2.5
2.3 - 4.3
2,950 - 28,900
8.2 - 17.3
74.1 - 149
7.3 - 20
0.33 - 3.1
6.1
250
9
->
*3
8
c
:
5
4
5
c
=
;
1
i
26
-------
TABLE 5 - REDWING SITE: ORGANIC AND INC
SEDIMENTS
- INDICATES TENTATIVELY IDENTIFIED COMPOUNDS (TICsl
b - INDICATES ORGANIC COMPOUND WHICH WAS ALSO
DETECTED IN THE ALLUVIAL GRCUNDWATER
CHEMICALS
SODIUM
VANADIUM
ZINC
IRGANIC CONSTITUI
RESULTS OF ANALYSIS
FROM BACKGROUND SOILS
RANGE OF CONCENTRATIONS
DETECTED (|ig/kg>
40.9 - 46.3
6-17
1.9 - 31.9
SNTS DETECTED IN
RESULTS OF ANALYS7- '
SEDIMENTS
RANGE OF CONCENTRATIONS
DETECTED (Jig /kg!
41 - 3.500
9.4 - 29.2
17.- - 30. e
DITCH
Cv DT7CK
N£ . Of
*i
4
~
commingled with the sludge. This combination shall be referred
to as the "source material". Various classes of compounds were
distributed across areas of the former terminal operations.
Volatile organic compounds (VOCs) and aromatic compounds are
generally less persistent in surficial soil and surface water.
The VOCs are most persistent in groundwater. The semivolatile
compounds detected at the Redwing Site are found to be insoluble
in the groundwater with the exception of the phenols. Some of
the Polycyclic Aromatic Hydrocarbons (PAHs) are very persistent
and tend to bioaccumulate in the environment although no
significant concentrations were found in the groundwater at the
Redwing Site.
Pesticides and herbicides detected at the Redwing Site are
chlorinated hydrocarbons such as aldrin and carbamate compounds
such as butylate. These compounds are not easily water soluble;
however, they are persistent and tend to remain in groundwater
and soil once transport has taken place.
Inorganic chemicals are widespread naturally in the environment
and occur in varying concentrations. Inorganic chemicals in
aqueous form tend to be transported easily into groundwater and
surface water. Several inorganic chemicals were detected in the
groundwater at the Redwing Site.
The groundwater at the Redwing Site has been impacted by
contaminants coming from the source material. The highest
concentrations of contaminants in the groundwater occur in the
eastern half of the apartment complex but the surficial
groundwater has been impacted under almost the entire site.
The storm water from the Redwing Site contacts surface soils and
sludge seeps. The contaminated sediments in the unlined northern
ditch are also a current vehicle for transport of chemicals of
concern.
27
-------
5.6
SOURCE AREAS OF CONTAMINATION
The results of the remedial investigation identified eight areas
of the Redwing Site as the source of the groundwater
contamination. Those areas are shown on Figures 7 and 8. The
bulk of the sludge was detected in the eastern area of the
Redwing Site. This coincides with the area of highest
concentrations of groundwater contamination. The source material
(i.e. sludge commingled with soil) was also concentrated in the
central area of the Redwing Site, the northwest area near
building 1200 and in two areas near the southwest corner of the
Redwing Site.
Table 6 shows the estimated volumes of source material which were
evaluated from the data collected during the RI.
TABLE 6 AREAS AND VOLUME ESTIMATES FOR SOURCE
MATERIAL (INCLUDES SLUDGE) *
SOURCE
AREA
E-l
E-2 1
E-3 I
C-l 1
C-2 1
N-l I
SW-1 I
SW-2 |
TOTALS]
SQUARE
FEET
5,800
1,500
4,760
9,180
730
3,240
640
680
26,610
SLUDGE
THICKNESS
(FT)
2.0
0.5
2.4
1.2 '
2.5
1.5
2.0
1.0
n/a
SLUDGE
VOLUME
(CU. YDS)
433
29
423
408
68
180
47
25
1,613
SOURCE
MATERIAL
THICKNESS
(FT)
5
5
6
6
6
3.5
5
5
n/a
SOURCE
MATERIAL
VOLUME
(CU. YDS)
1,080
285
1,060
2,040
162
420
119
126
5,292
* Source material includes black sludge and influenced soils,
6.0
SUMMARY OF SITE RISKS
CERCLA directs that the EPA protect human health and the
environment from current and future exposu.e to hazardous
28
-------
FIGURE - 7
K)
10
-------
FIGURE - 8
I I f^t-k ll-\ II OanalM prob«bl. »r««l
LEGEND ( ) -i-Bl °r i«-'»
v x t«rl«l.
SB-I
e F..I
Soil
SA 4 I9BS II S EPA bnr Ing
T.r-
Soil 5 F..I tj.lo.
FIGURE-8 Aeriol extent
depths, csnd thicl-cness of
the tor-~llke moterlol.
-------
BLANK PAGE
31
-------
substances at Superfund sites. In order to assess the current
and future risks for th - "edwing Site, a baseline risk assessment
(BRA) was conducted as : _t of the Remedial Investigation. The
BRA consists of a human ialth and environmental assessment of
current and potential exposures at the Redwing Site.
As defined by the 1990 National Oil and Hazardous Substances
Pollution Contingency Plan (NCP), the BRA:
"characterize [s] the current and potential threats to human
health and the environment that may be posed by contaminants
migrating to ground water or surface water, releasing to air,
leaching through soil, remaining in the soil, and
bioaccumulating in the food chain."
40 C.F.R 300.430(d)'->. The BRA is organized into two major
components, the Huir Health Risk Assessment and the
Environmental Evalu . ;>n. The risk assessment processes are
evaluated within ea component.
6.1 CONTAMINANTS OF CONCERN
Tables 7A and 7B provide a comprehensive list of the contaminants
identified as chemicals of potential concern (COCs) at the site
in their various media. Chemicals provided in Tables 8A and 8B
are the contaminants which the baseline risk assessment (BRA)
indicated might pose a current or future significant risk. The
criteria for a significant risk was a carcinogenic risk level
within or above the acceptable risk range (i.e., 10E-4 to 10E-6),
or a hazard quotient greater than unity (1). Tables 8A and B
also provide the reasonable maximum exposure (RME) concentrations
which were used in the BRA.
The exposure point concentrations are based on the 95% upper
confidence limit (UCL) of the arithmetic average. The soil UCLs
are based on samples taken from the top 1 foot (12 inches) of
soils or sediments.
6.2 EXPOSURE ASSESSMENT
The exposure assessment is the identification of populations that
may be exposed to the constituent and the determination of the
potential magnitude and duration of their exposures. A
quantitative exposure assessment is the estimation of the
magnitude, duration and frequency of exposure to various
environmental media including both current and potential future
exposures.
32
-------
TABLE - 7A
CHEMICALS OF POTENTIAL CONCERN FOR SOILS. DITCH SEDIMENTS
AND TAR-LIKE MATERIAL
1.1,1-TRICHLOROETHANE
1,2,4-TRICHLOROBENZENE
1.4-DICHLOROBENZENE
2,4-D
2,4,5-T
2-BUTANONE (MEK)
4,4'-DDD
4,4'-DDE
4.4--DDT
4-METHYL-2-PENTANONE
4-METHYLPHENOL
ACENAPHTHENE
ACETONE
ALDRIN
ALPHA-BHC
ALPHA-CHLOROANE
ANTHRACENE
BENZALOEHYDE
BENZENE
BENZO(A)ANTHRACENE
BENZO(A)PYRENE
BENZO(B)FLUORANTHENE
BENZO(G.H,I)PERYLENE
BENZO(K)FLUORANTHENE
BETA-BHC
BIS(2-ETHYLHEXYL)PHTHALATE
BUTYLATE
CADMIUM
CARBON OISULFIDE
CARBON TETRACHLORIDE
CHLOROBENZENE
CHLOROFORM
CHLORPYRIFOS
CHROMIUM (III/VI)
CHRYSENE
CYANIDE
DI-N-BUTYLPHTHALATE
DI-N-OCTYL PHTHALATE
DIBENZ(A,H)ANTHRACENE
DICAMBA
DIELDRIN
DIETHYLPHTHALATE
ENDOSULFAN I
ENDRIN
EPTC
ETHYLBENZENE
FLUORANTHENE
FLUORENE
GAMMA-BHC (UNDANE)
GAMMA-CHLORDANE
HEPTACHLOR ,
HEPTACHLOR EPOXIDE
INDENO(1,2.3-CD)PYRENE
LEAD
MANGANESE
MERCURY
METHOXYCHLOR
METHYLENE CHLORIDE
MOUNATE
NAPHTHALENE
PEBULATE
PHENOL
PYRENE
SELENIUM
TETRACHLOROETHENE
TOLUENE
VERNOLATE
XYLENE
ZINC
33
-------
TABLE 7B
CHEMICALS OF POTENTIAL CONCERN IN GROUNDWATPR
Chemical
2.4-0
2,4-Dimethylphenol
2.4,5-T
2-Butanone
4.4'-DDT
4-MethyJ-2-Pentanone
4-Methylpheno<
Acetone
Aldrin
Alpha-BHC
Arsenic
Barium
Benzoic Acid
Beryllium
Bis(2-ethylhexyl)pntnalate
Butylate
Caprofactum
Carbon Disulfide
Chloroform
Chromium (III/VI)
Copper
Cyanide
Di-n-butylphthalate
Di-n-octylphthalate
Dieldrin
Endrin
EPTC
Gamma-BHC
Heptacrdor
Iron
Lead
Manganese
Detected in Alluvial Aquifer
*
*
*
*
*
*
*
*
s
*
Detected in Surficial Water
Table Unit
*
*
*
*
»
*
*
*
*
*
*
*
*
*
*
*
-------
TABLE - 7B
CHEMICALS OF POTENTIAL CONCERN IN GRQUNDWATER
Chemical
Methylene Chloride
Molinate
Naphthalene
Nickel
Pebuiate
Phenol
Selenium
Toluene
Vanadium
Vernolate
Zinc
Detected in Alluvial Aquifer
*
Detected in Surficial Water
Table Unit
*
*
*
*
*
*
*
*
* Detected in corresponding medium
35
-------
TABLE 8A - SURFACE SOIL AND SEDIMENTS RME CONCENTRATIONS
CONTAMINANTS OF CONCERN
BENZO (A) PYRENE
BENZO (B) FLUORANTHENE
BENZO (A) ANTHRACENE
CARBON TETRACHLORIDE
CHRYSENE
CONCENTRATION
RANGE
(jig/kg)
73 - 3,200
230 - 7,400
67 - 7,200
110,000
93 - 3,800
RME
CONCENTRATIONS
(Jig/kg)
671
3,170
2,880
25,600
2,660
TABLE 8B - GROUNDWATER RME CONCENTRATIONS
CONTAMINANTS OF CONCERN
4,4' -DDT
ACETONE
ALDRIN
ALPHA -BHC
ARSENIC
£RYLLIUM
BIS ( 2 -ETHYLHEXYL ) PHTHALATE
. CARBON DISULFIDE
CHLOROFORM
CHROMIUM
LEAD
METHYLENE CHLORIDE
NICKEL
VANADIUM '
VERNOLATE
CONCENTRATION
RANGE (ug/1)
0.96
10,000 -
2,100,000
0.11 - 0.47
0.044 - 0.15
4,000 - 29,800
1.3 - 9.5
2 - 620
9 - 5,500
2,900 - 27,000
6.2 - 355
2.4 - 162
330 - 650
28.7 - 301
6.6 - 580
1.1 - 140
RME
CONCENTRATIONS
(Jig/kg)
0.223.
1,520
0.121
0.0595
15
5.18
206
1,220
7,740
156
69.1
204
151
272
35.5
36
-------
The exposure assessment was conducted in three steps: (1)
identification of exposure pathways, (2) estimation of
environmental concentrations and (3) selection of exposure
assumptions and estimation of human intake. Included was an
evaluation of possible exposure doses to people currently living
at the Redwing Site and potential future exposure doses due to
groundwater.
Exposure pathways at the Redwing Site were defined in terms of
the following elements: (1) a source and mechanism of chemical
release into the environment, (2) an environmental transport
medium, (3) a point of potential human exposure and (4) an
exposure route (e.g., ingestion of drinking water).
The media considered for both present and potential future
exposure are: (1) gro.undwater (alluvial and surficial), (2) soils
and seeps of sludge (tar-like material), (3) air, and (4) on-site
ditch sediments.
Chemical concentrations used in the exposure assessment were
based on sampling data collected during the remedial
investigation. The exposure dose was calculated using the 95%
upper confidence limit (UCL) of the arithmetic mean of the
concentration unless this was greater than the maximum
concentration detected, in which case the maximum observed value
was used. Whenever possible, actual sampling data were used.
When sampling data was not available, environmental fate and
transport modeling was used to estimate concentrations based on
the .sampling data. Calculated chemical concentrations for the
exposure assessment used all detected concentrations of a
chemical plus half the quantification limit for each sample in
which that chemical was not detected. Only chemicals that were
detected in at least one sample from the Redwing Site were
included in these calculations. These data are summarized in
Tables XI-1 through XI-8 of Appendix XI of the RI Report for all
COCs. Table 8A & 8B of this section provide a summary of the
more significant contaminants and their respective RME
concentrations.
Based on sampling results and Site layout, four areas of possible
current exposure were identified as (1) the eastern portion of
the Redwing Site (Target Area E), (2) the western portion of the
Redwing Site not covered by apartment buildings or pavement
(Grassy Area), (3) the Northern Ditch and (4) the apartments'
living quarters. The Redwing Site was divided into these four
areas for fate and transport modeling and calculations of human
intake. The receptors considered for the exposure assessment
included an adult, a 9-year-old child (the average of a child
ages 6 through 12 years) and a 4-year-old child (the average of a
child ages 6 months through 6 years).
When site-specific data were not available, the exposure
37
-------
assumptions used in the risk assessment were based on standard
methodology. Tables 9 through L;, which were originally
presented in the RI Report as T. le 6-8 and Tables 6-10 through
6-13, identify assumptions used in the risk assessment are
provided in the following pages. In the tables and as presented
in the RI Report, the contaminated sludge is referred to as "tar-
like material."
6.2.1 EXPOSURE PATHWAYS
Groundwater: The surficial groundwater is a potential drinking
water source. For the City of Saraland, the alluvial aquifer is
a current and potential future drinking water source. Presently,
three municipal wells located within 1.5 miles of the Redwing
Site receive water from the alluvial aquifer. Although no wells
are located on the Redwing Site, there are several private wells
located within a one-mile radius of the ." edwing S:te. These
wells were installed at various depths a;.d contact the surficial
as well as the alluvial aquifer. Remedial Investigation sampling
data revealed contamination in on-site groundwaters, however, no
Site related contaminants were detected in off-site wells. The
potential future exposure associated with a well installed on the
Redwing Site was evaluated. The evaluation addressed potential
future exposure to groundwater from both the surficial and
alluvial aquifer as a result of ingestion and showering.
Soils: Exposure to soils and seeps at the Redwing Site may occur
through incidental ingestion, dermal contact or inhalation of
vapors and particulates. Actual exposure at the Redwing Site has
not been measured, therefore, conservative default estimates were
used. Possible exposure to soils and seeps was estimated by
proportionally dividing exposure (time of contact and ingestion
mass) among the three outdoor areas (Target Area E, Grassy Area
and Northern Ditch) and seeps for relative .i.ntribution of risk.
Seeps (Sludge): The ongoing removal of seeps by Redwing has not
been incorporated into the BRA. The maximum seep area was
estimated using historical data in conjunction with ground-level
and aerial photographs from the period prior to the current seep
inspection and removal program. Additional seep analyses were
conducted which estimates exposure of sludge (tar-like material)
seeps found at the Redwing Site. Methodology assumptions used to
estimate the total seep area and the resulting risk estimates are
presented in Appendix XVII of the BRA.
This analysis resulted in a total seep area of 540 ft2 or 0.34%
of the potential exposure area (sum of Target Area E and Grassy
Area less the area of apartments and Northern ditch). The
population potentially exposed to the seeps are residents of
Saraland Apartments consisting of approximately 96 adults and 64
children. The estimate of seep constituent concentrations
include all samples of sludge regardless of depth.
38
-------
TABLE - 9
EXPOSURE ASSUMPTIONS FOR U/BK MODEL
Exposure Assumption
Air Data
Concentration (^g Pb/m3)
Lung Absorption
Breathing Rate (m'/d)
Diet Data
Intake (»g Pb/day)
Water Data
Jftmount Ingested (liters/day)
Soil/Dust Data
Percent of soil and dust that is soil
Amount ingested (mg/day)
Soil contribution to house dust
U/BK Default'
0.202
32.0%
4.5
6.38
0.48
45%
100
28%
Saraland Modification
NM
NM
8
NM
1.3
NM
200
NM
' Average for children ages 0 to 6 years old.
* Mean concentration in urban air (USEPA 1990b).
NM - Not modified.
39
-------
TABLE 10
SUMMARY OF USEPA ASSUMPTIONS
Exposure Assumptions
Ingestion of water
o Amount ingested per day
adult
-9-year-old
-4-year-old
o Years exposed (adult)
Showering
o Breathing rate
o Years exposed (adult)
Soil and tar-like material ingestion
o Amount ingested
-Adult
- 9-year-old
- 4-year-old
o Days/year exposed
adult and children
Dermal contact with soil (all areas)
o Adherence factor
sofl
tar-like material
o Days/year exposed
adult and children
Dermal Absorption
o Organics
o Inorganics
Vapor Inhalation indoors
o Days/year exposed indoors
adult and children
RAGS
(USEPA
1989b)/1991a)
2 liters
30 years
30 years
100 mg/day
100 mg/day
200 mg/day
350 d/year
350 d/year
350 d/year
Exposure Factors
Handbook
(USEPA 1989a)
1.5 liters
1.3 liters
0.6 m3/hr
New Interim Region
IV Guidance
(USEPA 1992)
I '
0.2 mg/cm2
1 .0 mg/cm2
1.0%
,_ 0.1%
40
-------
TABLE 11
SUMMARY OF NON-USEPA ASSUMPTIONS
Exposure Assumption
Showering
o Tim* exposed adult
o Years exposed (children)
Incidental ingestion of soil and
dermal contact (all areas)
o Years exposed-adult
Dermal contact with soil (all areas)
o Surface area
adult
9-year old
- 4-year old
Inhalation of particulates
o Contact time
Inhalation of vapors
o Outdoor-contact time
o Indoor-contact time
RAGS
(USEPA 19895)
7(12) min per day average
(worst) case
NA
30years-
90th percent) le at one
residence
Dependent on duration of
exposure
Dependent on duration of
exposure
Dependent on duration of
exposure
Hypothetical
Values Used in
Saraland Risk
Assessment
36 min/day
6/5.5 years
9.6 years
2756cm2
3655cm*
2522cm2
8 hr/day
8 hr/day
16 hr/day
Rationale for Non-USEPA
Assumptions
Adjust .for additional indoor air
exposure (e.g.. dishwasher)
due to volatilization from water
Number of years for each age
group
95% UCL for residence at
Saraland Apartments. Children
exposed over total age period.
Assumed face and 2/3 upper
limbs for adult, and face,
2/3 upper limbs and 1/2 lower
limbs for children (ICRP 1984)
Assumed to be the reasonable
maximum exposure time
outdoors
Assumed to be the reasonable
maximum exposure time
outdoors
Assumed to be the reasonable
maximum exposure time
indoors
-------
TABLE 12
GENERIC EXPOSURE ASSUMPTIONS1
Assumptions
Days per Lifetime
Years of Exposure4
Body Weight (kg)
Breathing Rate (m'/rir)
Total Body Surface Area (cm2)6
Surface Area of Lower Limbs (cm2) (37.5%)
Hands (cm2) (5.2%)
Upper Limbs (cm2) (18.8%)
Head and Neck (cm2) (7.8%)
Adult
25,550
9.6*
70
0.833
16,900
6." .17.5
£ .8
3,177.2
1.318.2
9-Year-2
Old Chad
25.550
69
31
0.6256
10,425
3.909.4
542.1
1,959.5
813.2
4-Year-3
Old Chad
25,550
5.5s
14.5
0.333'
7.195
2,698.1
374.1
1.352.7
561.2
Notes:
USEPA 1989a
3 Average of a child ages 6 to 12 years.
3 Average of a child ages 6 months to 6 years.
4 Upper 95th percentile value for residents currently residing at the Saraland Apartments. For
hypothetical groundwater exposure scenarios, 30 years (USEPA upper 95th percentile for
U.S. residence at a location) will be used.
9 Based on adult residence time of 9.6 years, child could theoretically reside at Saraland
Apartments for entire time period within this age group.
8 ICRP 1984.
-------
TABLE 13
SPECIFIC EXPOSURE SCENARIO ASSUMPTIONS FOR THE RME RECEPTOR
Exposure Scenario Assumptions
Adult
9-Year-
Old
Child
4-Year-
Old
Child
Reference
HYPOTHETICAL FUTURE EXPOSURE: Assumes future installation of water supply wells
INGESTION OF WATER. ALLUVIAL AQUIFER
Amount ingested (I/day)
Number of contacts total (days/yr * yrs exposed)1
INGESTION OF WATER. SURFICIAL WATER
TABLE UNIT (ON-SITE AND OFF-SITE)
Amount of water ingested (I/day)
Number of contacts total (days/yr * yrs exposed)1
SHOWERING, ALLUVIAL AQUIFER
Breathing Rate (m3/hr)
Time Exposed (hr/day)
Number of contacts total (days/yr*yrs exposed)1
SHOWERING, SURFICIAL WATER TABLE UNIT
(ON-SITE AND OFF-SITE)
Breathing Rate (m3/hr)
Time Exposed (hr/day)
Number of contacts total (days/yr yrs exposed)1
2
10500
2
10500
0.6
0.6*
10500
0.6
0.6s
10500
1.5
2100
1.5
2100
0.6
0.43
2100
0.6
0.43
2100
1.3
1925
1.3
1925
0.6
0.43
1925
0.6
0.4'
1925
USEPA 19893
1989b
USEPA
19895/1991 a
USEPA 1989a
USEPA
19890/1 991 a
USEPA 1989b
ENVIRON
USEPA
1989a/1991 a
USEPA 19696
ENVIRON
USEPA
1989a/1 991 a
CURRENT EXPOSURE
INGESTION OF SOIL Eastern sector
Amount ingested (kg/day)
Total time of ingestion (days/yr * yrs exposed)
Days exposed per year
Fraction of time in Eastern sector
INGESTION OF SOIL, Western/Central sector
Amount ingested (kg/day)
Total time of ingestion (days/yr * yrs exposed)
Fraction of time In Western/Central sector
INGESTION OF TAR -LIKE MATERIAL
Amount ingested (kg/day)
Ingestion time (days/yr ' yrs exposed)
Fraction of time exposed to seeps of tar-like
material
0.0001
3360
350
49.83%
0-0001
3360
49.83%
0.0001
3360
0.34%
0.0001
2100
350
72.83%
0.0001
2100
18.83%
0.0001
2100
0.34%
0.0002
1925
350
55.83%
0.0002
1925
38.83%
0.0002
1925
0.34%
USEPA 1989b
USEPA 1991 a/
ENVIRON
USEPA 19913
ENVIRON
USEPA 1989b
USEPA 1991 a/
ENVIRON
ENVIRON
USEPA 1989b
USEPA 19913/
ENVIRON
ENVIRON
-------
TABLE 13
SPECIFIC EXPOSURE SCENARIO ASSUMPTIONS FOR THE RME RECEPTQR
Exposure Scenario Assumptions
INGESTION OF SEDIMENTS. NORTHERN DITCH
Amount Ingested (kg/day)
Total time of ingestion (days/yr yrs exposed)
Fraction of time in ditch
DERMAL, SOIL, Eastern sector
Number contacts total (days/yr * yrs exposed)
Days expcted per yea'
Son to skin adher= :e factor (K^'cm2)
Dermal absorptio- 4)
Compounc Class Specific
organics
inorganics
Surface area of contact (cm2)
for Adult = Face + 2/3 Upper limbs
for NINE and FOUR = Face + 2/3 Upper
limbs + 1/2 Lower limbs
Fraction of time in Eastern sector
DERMAL, SOIL, Western/Central sector
Number contacts total (days/yr * yrs exposed)
Son to skin adherence factor (kg/cm2)
Dermal absorption (%)
Compound Class Specific (see above)
Surface area of contact (cm*)
Fraction of time in Western/Central sector
DERMAL, TAR-UKE MATERIAL
Number contacts total (days/yr * yrs exposed)
Soil to skin adherence factor (kg/cm2)
Dermal absorption (%)
Compound Class Specific (see above)
Surface area of contact (cm2)
Fraction of time exposed to seeps of taNike
material
Adult
0.0001
3360
0%
3360
350
2.00E-07
1%
0.1%
2756
49.83%
3360
2.00E-07
9-Year-
Old
Child
o.oooi
2100
8%
2100
350
2.00E-07
1%
0.1%
3655
72.83%
2100
2.00E-07
2756 3655
49.83%
3360
1.00E-06
2756
0.34%
18.83%
2100
1.00E-06
3655
0.34%
4-Year-
Old
Child
0.0002
1925
5%
1925
350
2.00E-07
1%
0.1%
2522
55.83%
1925
2.00E-07
2522
38.83%
1925
1.00E-06
2522
0.34%
Reference
USEPA 1989b
USEPA 1991 a/
ENVIRON
ENVIRON
USEPA 19913/
ENVIRON
USEPA 19913
USEPA 1992
USEPA 1992
USEPA 1992
USEPA 1989a
ENVIRON
ENVIRON
USEPA 1991 a/
ENVIRON
USEPA 1992
USEPA 1992
USEPA 1989a
ENVIRON
USEPA 1991 a/
ENVIRON
USEPA 1992
USEPA 1992
ICRP 1984/
ENVIRON
ENVIRON
-------
TABLE 13
SPECIFIC EXPOSURE SCENARIO ASSUMPTIONS FOR THE RME RECEPTOR
Exposure Scenario Assumptions
DERMAL SEDIMENT, NORTHERN DITCH
Number contacts total (days/yr * yrs exposed)
Soil to skin adherence factor (kg/cm2)
Dermal absorption (%)
Compound Class Specific (see above)
Surface area of contact (cm2)
Fraction of time in ditch
INHALATION - PARTICULATES, Eastern sector
Contact time (hr/day)
Number contacts total (days/yr ' yrs exposed)
Fraction of time in Eastern sector
INHALATION - VAPORS. Eastern sector
Contact time (hr/day)
Number contacts total (days/yr yrs exposed)
Fraction of time in Eastern sector
INHALATION - VAPORS, Western/Centra) sector
Contact time (hr/day)
Number contacts total (days/yr * yrs exposed)
Fraction of time in Western/Central sector
INHALATION - VAPORS, TAR-LJKE MATERIAL
Contact time (hr/day)
Number contacts total (day/yr * yrs exposed)
Fraction of time exposed to seeps of tar-like
material
INHALATION - VAPORS. INDOORS
Contact time (hr/day)
Number contacts total (days/yr * yrs exposed)
Fraction of time indoors
Adult
3360
2.00E-07
2756
0%
2
3360
49.83%
2
3360
49.83%
2
3360
49.83%
2
3360
0.34%
22
3360
100%
9-Year-
Old
Child
2100
2.00E-07
3655
8%
2
2100
72.83%
2
2100
72.83%
2
2100
18.83%
2
2100
0.34%
22
2100
100%
4-Year-
Old
Child
1925
2.00E-07
2522
5%
2
1925
55.83%
2
1925
55.83%
2
1925
38.83%
2
1925
0.34%
22
1925
100%
Reference
USEPA 1991 a/
ENVIRON
USEPA 1992
USEPA 1992
ENVIRON
ENVIRON
ENVIRON
USEPA 1991 a/
ENVIRON
ENVIRON
ENVIRON
USEPA 1991 a/
ENVIRON
ENVIRON
ENVIRON
USEPA 1991 a/
ENVIRON
ENVIRON
ENVIRON
USEPA 1991 a/
ENVIRON
ENVIRON
ENVIRON
USEPA 1991 a/
ENVIRON
ENVIRON
1 Based on default USEPA value for length of residence, 350 days per yean 30 years (adult). 6
years (9 year old) and 5.5 years (4 year old).
2 Based on Inhalation during 15 minute daily shower and additional exposure to other voiatues for
20 minutes per day.
3 Based on inhalation during 24 minute bath.
45
-------
Air: Although exposures have not been measured, exposure to
constituents through inhalation of vapor and particulates
ispossible. Possible exposures to vapors in the grassy area,
indoors, target area E and the sludge have been evaluated via
mathematical modeling. Indoor exposure may occur from the
inhalation of vapor that may diffuse through concrete foundation
cracks or utility openings. In addition, outdoor ambient air
concentrations can contribute to indoor air concentrations.
Total indoor air concentrations were estimated from the sum of
modeled indoor and outdoor ambient air concentrations.
6.3 TOXICITY ASSESSMENT: DOSE RESPONSE EVALUATION
The toxicity assessment evaluates the adverse effects on humans
due to exposure to the chemicals of concern. The dose-response
evaluation is the characterization of the relationship between
the dose received and the resulting effect. The toxicity values
are then derived from quantitative dose-response relationships.
These values are used to predict the incidence or probabili-y of
an adverse effect occurring relative to a dose. Toxicity values
are used during risk characterization to estimate the possibility
of an adverse effect occurring under a given set of
circumstances.
Scientists have developed several mathematical models to
extrapolate low-dose carcinogenic risks to humans based on
carcinogenicity observed at high doses typically used in
experimental animal studies. These models provide an estimate of
the upper limit on lifetime cancer risk per unit dose,
Carcinogenic Slope Factor (CSF). The mathematical model used by
EPA to generate CSFs is a linearized multistage model.
Non-carcinogenic risks for long-term exposures are characterized
by the chronic reference dose (RfD) for ingestion, or reference
concentration (RfC) for inhalation which is similar in concept to
an "acceptable daily intake." The RfD or RfC represents an
estimate of daily exposure that is not expected to result in an
increased risk of adverse health effects. Initially, the
threshold dose is identified by determining the
no-observed-effect level (NOEL), or, if a NOEL is not available,
the lowest-observed-effect level (LOEL) from observations of
people or experimental animals.
Toxicity values developed by EPA (RfDs, RfCs, and CSFs) have been
used to characterize risk for all compounds except Lead and PAHs.
Lead and PAHs are discussed below. Table 14, summarizes utilized
toxicity values from Appendix XII of the RI report.
For polynuclear aromatic hydrocarbons (PAHs), a CSF has been
onlyestablished for benzo(a)pyrene (BaP). Therefore, a Region IV
interim guidance document has recently adopted a toxicity
46
-------
TABLE - 14
REFERENCE DOSES. REFERENCE CONCENTRATIONS AND CANCER SLOPE FACTORS
CHEMICAL
Acenaphthene
Acetone
AJdrln
Anthracene
Benz(a)anlhracene*
Bens(a)pyrene
Benialdehyde
Benzene
Benio(b)fluorenlhene'
Bemo(ghl)perylene
Benzo(k)fliiorantlMfw*
BeniotoAcW
Bls(2-elhy(hexyt)phthalate (BEHP)
Bulylete
Caprolactam
Carbon dlsulflda
Carbon tetrechlorlde Tetfachroromethane
NON-CARCINOCENIC
lekeLWC
Imifln/tor)
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
2.86 x 10 '
NA
InhaL RIC
SOURCE
HEAST 1991
Oral RID
(mc/M/tfar)
6.00x10*
1.00 X 10 '
3.00 X 10 9
300 X 10 '
NA
NA
1.00x10*
NA
NA
300x10*
NA
4.00
2.00 x 10*
5.00 x 10*
5.00 x 10 '
1.00 x 10 '
7.00 x 10"*
Oral RID
SOURCE
HEAST/inS 1991
HEAST/inS 1991
HEAST/IRIS 1991
HEAST/IRIS 1991
HEAST 1991
HEAST/IRIS 1991
HEAST 1991
HEAST/IRIS 1991
HEAST/IRIS 1991
HEAST 1991
HEAST/IRIS 1991
HEAST/IRIS 1991
CARCINOGENIC
InkiL CSF
l/(mj/lt/day)
NA
NA
1.70 x 10*
NA
6.10x10*
6.10
NA
2.90 x 10 *
6.10x10*
NA
6.10x10*
NA
NA
NA
NA
NA
1.30 x 10 *
InhiL CSF
SOURCE
HEAST/IRIS 1991
HEAST 1991
(BaP TEF)
HEAST 1991
HEAST/IRIS 1991
HEAST 1991
(BaP TEF)
HEAST 1991
(BaP TEF)
HEAST/IRIS 1991
Oral CSF
l/d-tAt/**)
NA
NA
1.70 x 10*
NA
5.80x10*
5.80
NA
2.90 x 10*
5.80x10*
NA
5.80x10*
NA
1.40 x 10*
NA
NA
NA
1.30x10'
Oral CSF
SOURCE
HEAST/IRIS 1991
HEAST 1991 (BaP
TEF)
HEAST 1991
HEAST/IRIS 199t
HEAST 1991
(BaP TEF)
HEAST 1991
(BaP TEF)
HEAST/IRIS 1991
HEAST/IRIS 1991
-------
TABLE -14
REFERENCE DOSES. REFERENCE CONCENTRATIONS AND CANCER SLOPE FACTORS
CHEMICAL
Chlordana (alpha)
Chlordan* (gamma)
ChtorolMnzviM MooocJitorobanMo*
Chloroform TrteMoromattwiw
Chlorpyrlfot
CfiiyMn*'
Crawl (p-) (4-Mattiyl Phanol)
2.4-0 (2.4 OcMoroptwnoxyacctio acid)
Ol-n-btilyl pttihalai*
Oi-fl«dyl phthalat*
Dib«ni(a,h)anttiracan«l
DteamtM
»!-_ t- M. * >
p-OeMorobantafl*
DfchlprodlprMflyl dteMonMttuM (p.p1-)
(ODD)
DtcMofodlphanyl dtehtonMttiyton* (p-pl
(DOE)
NONr>
1.30
1.30
NA
8.10x10*
NA
6.10x10*
NA
NA
NA
NA
6.10
NA
NA
NA
NA
IrtaL CSF
SOURCE
HEAST/IWS 1991
HEAST/IRIS 1991
HEAST/IRIS 1991
HEAST 1991
(BaPTEF)
HEAST 1991
(OaPTEF)
OnlCSF
i/(m/i«/-'-.>
1.30
1.30
NA
6. 10 x Iff4
NA
5.80x10*
NA
NA
NA
NA
6.60
NA
2.40x10*
2.40 xlO'1
3.40 x 10 '
OnlC5F
SOURCE
HEAST/IRIS 19!
HEAST/lfVS 10
HEAST/IRIS 19S
HEAST 1991
(BaPTEF)
HEAST 1991
(BaPTEF)
HEAST 1991
HEAST/IWS 1991
HEAST/IRIS 1891
/.a
-------
TABLE -14
REFERENCE DOSES. REFERENCE CONCENTRATIONS AND CANCER SLOPE FACTORS
CHEMICAL
Dichkxodlphanyftrlchloroethan* (p.p1-)
(DDT)
DiolhyiphthalalB
Oleldrln
Dimalhylphanol (2.4-)
Endosulfan
Endosulfan IIs
Endrln and meiaboliwi
Ethyl
-------
CHEMICAL
Mwx>(1.2.3)pyr«n«'
Mithoxychtof
Mtltiyt %< MI-M ;f,n K) - 2-txitanon*
Mrthyt Itobutyi fc
Pfwnol
2.4.5-T
Tolu«n* Toluol
Ttlctik)fOb«nw» (1,2.4-)
TflchkKO«tti«n» (1.1,1-)
Vtmolit*
Xyten*a
TABLE -14
NA
NA
9.00 x 10 *
8.60 x JO'
NA
NA
NA
NA^
NA
NA
_NA_
8.71 x 10'
NA
8.60 x 10 *
)NCENTRAT»ON!
NON^CARCINOCENIC
hluLRIC I OralRfD I OralRfD
SOURCE
0.00
SOURCE
HEAST 1991
HEAST 1991
HEAST 1991
HEAST 1991
HEAST 1991
HEAST 1991
HEAST 1991
g.OO »
5.00 K 1Q»
5.00 n 10'*
6.00 n
2.00
4.00 K
5.00x10^
6.00 ii 10 '
^3.00 x 10*
1.00 K 10a
j.oomo-a
_2.00 ic 10 *
t.31
1.00K103
2.00
HEAST/IRIS 1991
HEAST
HEAST 1991
HEAST/IRIS 1991
HEAST/IRIS 1991^
HEAST 1991
'1991
HEAST/IRIS 1991
HEAST/IHIS 1991
HEAST/intS 1991
HEAST/IRIS 1991
HEAST 1991
HEAST 1991
HEAST 1991
HEAST/IRIS 1991
lnh.1 CSP
6.10x10'
NA
NA
NA
1.65 XJIO3
_NA_
NA
NA_
NA
_NA_
NA
InkiL CSP
SOURCE
HEAST 1991
JBaP TEF)
CARCINOGENIC
Oral CSP
HEAST 1991
HEAST 1991
5.80 x 10'
_NA_
NA
_NA_
7.50 xIQ"3
_NA
NA
_NA_
NA^
_NA_
_NA_
'.10x10*
_NA_
_NA_
_NA_
_NA_
NA
r>0
-------
TABLE -14
REFERENCE DOSES. REFERENCE CONCENTRATIONS AND CANCER SLOPE FACTORS
CHEMICAL
Arsenic
Barium
Beryllium
Cadmium dusts & tails ( Cd)
Chromium (III)
Chromium (VI)
Copper
Cyanides ( CM)
Manganese
Mercury Inorganic
Ntefcel
Selenium
Vanadium
Zino and oompoundi
NON-CARCINOCENIC
lakaLMC
(«c/ks/
NA
NA
NA
NA
5.70 X 10 r
5.70 x 10'7
NA
NA
1.14 x 10"*
8.57 x 10 9
NA
NA
NA
NA
InhiL RfC
SOURCE
HEAST 1991
HEAST 1901
IRIS 1991
HEAST 1991
Oral RID
(rac/kc/da;)
3.00 x 10~*
7.00 x 10'*
.5.00x10'
5.00 x 10"*
1.00
5.00 x Iff3
1.00
2.00 x 10*
1.00 x 10 '
3.00 xHT4
2.00 x 10*
5.00 x 10^
7.00 x 10"3
2.00 x 10 '
Oral RID
SOURCE
IRIS 1991
IRIS 1991
IRIS 1991
HEAST/IRIS 1991
HEAST 1991
IRIS 1991
IRIS 1991
HEAST 1991
IRIS 1991
HEAST 1991
HEAST 1991
IRIS 1991 .
HEAST 1991
HEAST 1991
CARCINOGENIC
InNaL CSF
l/(iH8/kg/d.r)
5.00 x 10*
NA
8.40
6.30
NA
4.20 x 10*
NA
NA
NA
NA
8.40 x 10 '
NA
NA
NA
Inhal CSF
SOURCE
HEAST 1991
IRIS 1991
IRIS 1991
IRIS 1991
HEAST 1991
Oral CSF
l/(mt/ftt/«iay>
1.75
NA
4.30
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Oral CSF
SOURCE
IRIS 1991
IRIS 1991
*
1 Cancer elope factou have been adjusted using toxlclty equivalency factor (TEF) methodology as cited In New Interim Region IVGuidanct. February 1992 memo from USEPA Region IV.
2 HEAST 1991 and IRIS 1991 provide references for Endosulfan only. These values were also used for Endosuffan II.
-------
equivalency factor (TEF) methodology for carcinogenic PAHs based
on the relative potency of each compound to the potency of BaP.
The oral CSF for BaP is 5.8 (mg/kg-day)"'. Therefore, compounds
with a TEF of 0.1 were evaluated using oral CSFs of 0.58 (mg/kg-
day)'1. This TEF approach was used for inhalation, dermal and
oral exposure pathways (see Table 15).
TABLE 15 - TOXICITY EQUIVALENCY FACTORS (TEFs) FOR POLYNUCLEAR
AROMATIC HYDROCARBONS (PAHs)
Compound TEF
Benzo(a)anthracene 0.1
Benzo(b)fluoranthene 0.1
Benzo(k)fluoranthene 0.1
Chrysene 0.01
Dibenzo(a,h)anthracene 1.0
Indeno(l,2,3-c,d)pyrene 0.1
For Lead, the RfD or CSF currently does not exist, nor are value's
likely to be developed in the foreseeable future due to
difficulty of detecting effects of very low levels of lead
exposure. The Uptake/Biokinetic (U/BK) model, developed by
Harley and Kneip (USEPA 1991b), has been used by the USEPA Office
of Air Quality Planning and Standards to set the National Ambient
Air Quality Standards (NAAQS) for lead. Also, the Environmental
Criteria and Assessment Office (ECOA) has distributed the U/BK
model as a method for establishing soil cleanup levels for lead.
Accordingly, the U/BK model was used in the Risk Assessment for
this site as the most appropriate method currently available to
estimate the potential risks associated with exposure to lead.
6.4 RISK -lARAv-TERIZATION
Human health risks are characterized for potential carcinogenic
and noncarcinogenic effects by combining exposure and toxicity
information. Excessive lifetime cancer risks are determined by
multiplying the estimated daily intake level with the cancer
potency factor. These risks are probabilities that are generally
expressed in scientific notation (e.g., 1'x 10"6) . An excess
lifetime cancer risk of IxlO'6 indicates that, as a plausible
upper bound, an individual has a one in one million additional
(above their "normal risk) chance of developing cancer as a result
of site-related exposure to a carcinogen over a 70-year lifetime
under the assumed specific exposure conditions at a site.
The Agency considers individual excess cancer risks in the range
of IxlO"4 to IxlO'6 as protective; however the IxlO'6 risk level is
generally used as the point of departure for setting cleanup
52
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levels at Superfund sites. The point of departure risk level of
IxlO"6 expresses EPA's preference for remedial actions that
result in risks at the more protective end of the risk range.
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
contaminants'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 there may be a concern for potential
health effects resulting from the cumulative exposure to multiple
contaminants within a single medium or across media. Tables 16
and 17 provide a summary of specific carcinogenic and
noncarcinogenic risks respectively. The future potential
exposure to the surficial and/or alluvial aquifer were the only
pathways which represent an unacceptable risk.
6.5 UNCERTAINTY ANALYSIS
Throughout the risk assessment process, uncertainties associated
with evaluation of chemical toxicity and potential exposures
arise. 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 risk associated with potential
exposure at the Redwing Site.
Because of the uncertainty in the calculation of the total area
occupied by seeps, three different estimations of seep area were
conducted in the risk assessment. This was done to quantify the
range of possible exposure and the resulting risks at the Redwing
Site. These calculations are presented in the RME scenario
(Section 6.2.3.4) of the RI Report and in Appendix XVII of the
Report.
Since 1985, a seep inspection and removal program has been
implemented at the Redwing Site. As a result, seeps have not
been observed to increase in size beyond approximately 2 inches
in diameter. However, the risk assessment was conducted to
evaluate risks associated under the conditions that would occur
at the Redwing Site if the removal actions were not occurring.
53
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TABLE 16 - SUMMARY OP PATHWAY SPECIFIC CARCINOGENIC
RISKS
E 705'JRE SCENARIO
ALLUVIAL ACVIFSR
ingest ion of water
inhalation during showering
SUHFICIAL AQUIFER
ingest ion of water
inhaiation during showering
ADULT
CANCER
RISK
9 YEAR OLD
CANCER RISK
4 YEAR OLD
CANCER RISK
SUM OF 9 AND
4 YEAR OLD
CANCER RISK
5xl
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TABLE 17 - SUMMARY OF PATHWAY SPECIFIC TOTAL HAZARD
INDICES (NON-CARCINOGENIC RISKS)
EXPOSURE SCENARIO
ADULT
ALLUVIAL AQUIFER.
Ingest ion of water
Inhalation during showering
SUr.FICIAL AC'-IFER
i~3-~stion of water
Inhalation during showering
2xioc
0
NINE-YEAR-
OLD
FOUR-YEAH-
OLD
4X10°
0
3X101
8X10°
5X101
ix:o:
ex:?°
0
9X101
3x:c:
TARGET AREA E
ir.gesticn of soil
dermal contact Iw/soil)
inhalation (vapors)
inhalation (particulates)
4X1C"
2X10-'
ixio-'
3X10"
ixio"
8X10'J
2x:o-J
8X10'2
5X10-1
9X10"
2X10-)
7X10"
GRASSY AREA
ingestion of soil
dermal contact (w/soil)
inhalation (vapor)
3X10°
9X10-1
2X10'4
2X10'J
ixio-4
1X10"
2X10"
3X10-4
2x:o-4
INDOOR EXPOSURE
inhalation of vapor (includes seeps!
inhalation of vapor (excludes seepsl
3X10"
5X10"
5X10-'
8X1C-'
SX10"
9X10-'
NORTHERN DITCK
ingestion of sediments
dermal contact with sediments
EXPOSURE TO SEEPS OF SLUDGE.
ingestion of sludge
dermal contact with sludge
inhalation of vapors
TOTAL CURRENT BXPOSTOB
[Includes risks from eastern+western/ central*
indccr-ditch»seeps . ]
TOTAL POTBHTXAL KXPOSOTB
Includes currents exposure + exposure co the
alluvial aquifer.
Includes current exposure » exposure to the
surficial groundwater.
0
0
ixicr4
2X10'5
2X10"'
1X10''
3X10°
4X101
7X10-'
3X10-'
3X10"
6X10'5
4X10"
SxlO'1
5X10"
6X1 01
2x:c-J
3X10'4
1X10"
9X10-5
4X10"
7x10"
9X10°
1X10'
55
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.-"! alte. .tive se=p a.-alysis -'as conducted assuming a maximum
i.;ssibl. eep area of 10,400 _c2. This is 20 times greater than
tne arei used in the RME scenario. Using the alternative seep
analysis, Els for the 9 and 4-year-old children exceed 1. The
alternative seep area also increased carcinogenic risks under the
current exposure scenario by an order of magnitude.
6.6 HUMAN HEALTH SUMMARY
EPA evaluated present and possible future exposure from 1)
surficial and alluvial groundwater, 2) soils and seeps of sludge,
3) air and (4) site surface water and sediments. The risk
assessment indicates that contaminant levels in surface soil,
sediments and sludge seeps are not high enough to pose a
significant health threat via current exposure. Furthermore,
there is no current exposure to people from voundwater or
subsurface soil contamination. However, CO' :ould pose a future
health risk if the surficial aquifer were u: as a source of
potable water or if contamination moves int \e alluvial
aquifer. Additionally, COCs may pose a hea. risk if the PAHs
detected under the concrete liner become ex sd because of the
removal of the liner, or if similar contami..... _ion is found
elsewhere along the drainage pathway. The COCs in the northern
ditch do not currently present a significant human health threat.
6.7 ENVIRONMENTAL EVALUATION
The environmental evaluation examined the potential for adverse
ecological impacts as a result of the presence of the chemicals
at the Redwing Site. The evaluation was conducted in four steps:
(1) identification of the presence of critical habitats _and
species of concern, (2) identification of chemicals of potential
concern, (3) estimation of a.:ute and chronic toxicity and
exposure concentrations, and >4) comparison of toxicity threshold
estimates and exposure estimates.
The ecological risk assessment primarily addressed risk to on-
site receptors. The Redwing Site is mostly a non-vegetated, non-
aquatic habitat in an urban/residential area and does not provide
any special or unique habitats. Therefore, it is unlikely to
attract or support endangered or threatened species. Terrestrial
(land) plants are limited to mowed grass and a few bushes and
trees. Animals likely to be found at the Redwing Site are song
or field birds, small rodents, frogs, and possibly reptiles.
Although Redwing Site contaminants might have harmful effects on
some plants and animals, the source area is presently covered
with soil making direct exposure unlikely. Wildlife would
probably avoid the tar seeps. Therefore, the source material
does not a. pear to pose an environmental risk.
56
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Site ditches provide only temporary habitats for aquatic plants
and animals. Two aquatic species, the arrowhead plant and the
mosquitofish, were observed in the concrete-lined ditches
following heavy rainfall. The mosquitofish would likely move
downstream as water in the ditch dries up. Since contaminants in
unlined ditch sediments could move downstream and those in the
lined ditch could have moved in the past, data from on-site ditch
sediments were used to predict effects on plant and animal life
in downstream surface water bodies. The analysis indicated that
the highest contaminant concentrations were found under the
concrete liner in the ditch and measurable levels of contaminants
are not presently moving off site. Dilution factors were applied
to the maximum detected ditch sediment concentrations to
determine possible sediment contaminant levels downstream in
Norton Creek resulting from any past migration. Comparison of
these levels with toxicity information indicated that possible
past migration of sediment contaminants downstream into Norton
Creek would have little effect on the aquatic biota.
For specific information on EPA's environmental and human health
evaluations, refer to the Baseline Risk Assessment portion of the
RI Report.
6.7.1 UNCERTAINTY ANALYSIS
The major uncertainties associated with the environmental
evaluation are the extrapolation of soil/ditch sediment
concentrations to actual exposures. In addition the
extrapolation of laboratory toxicity data on pure compounds or
specific complexes to the Redwing Site, where the actual
environmental forms are unknown, adds to the uncertainty.
6.8 RISK ASSESSMENT SUMMARY
The health risk posed at this site is primarily from the future
use of the groundwater in both the surficial and alluvial aquifer
as a potable source. This is due to the presence of contaminants
presently at concentrations above EPA's Maximum Containment
Levels for drinking water. Surface soils and sediments are
subject to contamination from the continual leaching of
contaminants from the sludge which percolates to the surface.
With regard to environmental risks, there are no permanent on-
site aquatic habitats and the only on-site surface water bodies
are intermittent ditches. The highest sediment contaminant
levels are under the lined ditch and therefore not presently
available to migrate along the surface water pathway. Dilution
factors, with respect to possible effects on aquatic biota on
surface water bodies downstream, show that there would be no
adverse effect on aquatic biota from sediment contaminant levels.
57
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6.9 CHEMICALS OF CONCERN AND CLEANUP LRVRT.fi
The chemicals of potential concern were determined during the
risk assessment. All constituents detected at the Redwing Site
were initially considered as chemicals of potential concern. The
results of the risk assessment have provided a basis for
narrowing that list to those constituents in the soils which pose
a threat via the direct contact (ingestion and inhalation) route
and via the migration pathway to groundwater. The chemicals
determined for the remedial investigation to be of potential
concern to human health and the environment and their respective
protective cleanup levels for soils and sediments are presented
in Tables 18 and 19. Additionally, Table 20 lists protective
groundwater concentrations. These allowable post-remediation
concentrations are based upon the current groundwater protection
standard (MCL) or where such standards are not available, the
number is based on the results of the risk assessment which
constitute health-based cleanup goals.
6.10
CONCLUSION
Actual or threatened releases of hazardous substances from this
Site, if not addressed by implementing the response action
selected in the ROD may present an imminent and substantial
endangerment to public health, welfare, or the environment.
TABLE 18 - CLEANUP LEVELS FOR SUBSURFACE SOIL
CONTAMINANTS OF CONCERN
4, 4 '-DDT **
ACETONE
ALDRIN
ALPHA-BHC
CHLOROFORM
. CHROMIUM
DIELDRIN
GAMMA -BHC (LINDANE)
METHYLENE CHLORIDE
CONCENTRATION
RANGE
(Jig/kg)
0.48 - 140
3 - 2,300
0.67 - 200
0.1 - 4.7
4 - 46,000
2,800 - 52, 900
0.57 - 6.3
2.5 - 54
3-89
CLEANUP
LEVEL *
(Jig/kg)
566
36
4
0.5
70
47,000
0.1
3.2
0.6
58
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TABLE 18 - CLEANUP LEVELS FOR SUBSURFACE SOIL
CONTAMINANTS OF CONCERN
NICKEL
VANADIUM **
VERNOLATE
CONCENTRATION'
RANGE
(ug/kg)
3,000 - 36,500
1,800 - 50,200
2 - 130,000
CLEANUP
LEVEL *
(ug/kg)
30,000
156,000
55
* Cleanup levels are based on groundwater protection. If
lead is detected in subsurface soils not already cited for
remediation because cleanup levels above are exceeded, and the
concentration of lead is above 541 OOP liq/kcr, then
groundwater and soil characterization will be conducted to
determine if soil cleanup is required for the protection of
groundwater at 15ng/l, the current action level for lead in
groundwater.
** Concentrations of these site related contaminants were
detected above cleanup levels in groundwater during the
remedial investigation but not in the subsurface soils. Their
current existence in subsurface soils above cleanup levels
must be verified.
TABLE 19 - CLEANUP LEVELS FOR SURFACE SOIL AND SEDIMENTS
CONTAMINANTS OF CONCERN
BENZO (A) PYRENE
BENZO (B) FLUORANTHENE
BENZO (A) ANTHRACENE
CARBON TETRACHLORIDE
CHRYSENE
CONCENTRATION
RANGE
(jig/kg)
73 - 3,200
230 - 7,400
67 - 7,200
110,000
93 - 3,800
CLEANUP LEVEL
(jig/kg) *
94.9
540 1
1,025
9,590
362
* Based on risk from inhalation or ingestion
59
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TABLE 20 - CLEANUP LEVELS FOR GROUNDWATER
CONTAMINANTS OF CONCERN
4,4' -DDT
ACETONE
ALDRIN
ALPHA-BHC
BERYLLIUM
BIS (2- ETHYLHEX YL ) PHTHALATE
CARBON DISULFIDE
CHLOROFORM
CHROMIUM
DIELDRIN
GAMMA - BHC (LINDANE)
METHYLENE CHLORIDE
NICKEL
VANADIUM
VERNOLATE
CONCENTRATION
RANGE (Hg/1)
0.86
10,000 - 2,100,000
0.11 - 0.47
0.044 - 0.15
1.3 - 9.5
2 - 710
9 - 5,500
2,900 - 27,000
6.2 - 355
0.012 - 1.1
O.OL- 0.7
330 - 650
28.7 - 301
6.6 - 580
1.1 - 140
CLEANUP LEVEL
(Hg/1) * .(
0.158
1,120
0.00317
0.00855
4.00
6.00
47.6
100
50
.00337
0.2
5
100
78.1
11.2
* Based on MCL or Risk Assessment
60
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7.0
DESCRIPTION OF ALTERNATIVES
The Feasibility Study Report evaluated possible alternatives for
remediation of conditions at the Redwing Site. A total of six
(6) alternatives have been established for detailed analysis
consideration. These alternatives were selected to provide a
range of remedial actions for the Redwing Site.
1.
2.
3.
4.
5.
6.
No Action
Continuing Response Action
Collection of Source Material and Off-
Site Treatment Disposal; Extraction of
Groundwater with On-Site Treatment and
Off-Site Disposal to a POTW
RCRA Cap
Concrete Cap
Collection of Source Material and On-
Site Treatment Disposal; Extraction of
Groundwater with On-Site Treatment and
Off-Site Disposal to a POTW
7.1
ALTERNATIVE No. 1 - 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 developed alternatives. Under
this alternative the seep inspection and removal program
currently being conducted by Redwing under a removal order would
cease. Sludge seeps would be allowed to emerge unchecked and the
EPA would not take further action to minimize the impact that
soil contamination would have on the groundwater. Contaminants
in the soil would continue to leach into the groundwater. Levels
of contamination would continue to exceed groundwater protection
standards. The overall remedial action levels would not be
achieved by utilizing this alternative. There is no cost
associated with this alternative since no actions would be
conducted.
7 .2 ALTERNATIVE No. 2 - Inspection and Seep Removal with
Groundwater Monitoring
This alternative consists of inspection for and removal of
surfaced seeps of sludge along with monitoring surficial and
61
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alluvial groundwater quality and movement. This alternative
contains some of the elements currently being conducted under an
Administrative Order by Redwing Carriers, Inc. Groundwater
remediation is not addressed by this alternative. Under this
alternative, institutional controls and natural attenuation of
the contamination within the surficial and alluvial groundwater
would be the mechanism to prevent exposure and groundwater
remediation respectively. The estimated costs for this
alternative is $558,000 for the thirty (30) years of
implementation. However, the timeframe for natural attenuation
to occur has not been determined.
7 .3 ALTERNATIVE No. 3 - Excavation of Source Material,
Extraction of Surficial Groundwater with Off-Site
Treatment and Disposal of each. Groundwater Monitoring
of the Alluvial Aquifer.
This alternative involves excavation and transportation of soil
and sludge (i.e. source material) to an off-site treatment and
disposal facility. Additionally, extraction and disposal of
contaminated surficial groundwater would be required.
Groundwater monitoring of the alluvial aquifer would be
implemented to assure attenuation of the contaminant levels.
Source material and groundwater pre-treatment may be required
prior to disposal. This may require thermal and biological
treatment of soils and groundwater, respectively. Excavated
subsurface soils may require dewatering and stabilization prior
to land disposal. This water will be analyzed and
treated/disposed of in an appropriate manner. Excavation may be
accomplished with or without the removal of buildings or
structures in areas requiring excavation. Currently, there is no
evidence that contamination exists under the buildings. However,
if contamination is found during the remedial design appropriate
action, which may involve the demolition of some buildings, will
be undertaken. EPA will consult the public before taking this
action.
The areas of soil and sludge would be excavated. Residents would
be temporarily relocated during the period of excavation. Source
materials would be moved to a staging area on-site prior to being
hauled off-site. Some of the excavated soils will be removed
from the saturated zone and will require dewatering. Sidewalk
slabs and pavement areas may be contaminated and thus require
removal. Excavated areas would be backfilled with clean
material. The excavated material would be sorted and
characterized to determine if treatment is required before land
disposal. If treatment is required it will be conducted off-site
at an approved facility. All excavated soil, source material,
sludge, and contamina- =d debris will be disposed of off-site at
an approved facility. :t is estimated -.nat the excavation and
removal would be accoir ..Dished in 18 months.
62
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Alternative 3 also includes extraction and active treatment of
the surficial groundwater. Under this alternative contaminated
groundwater would be extracted, treated on-site and discharged to
the POTW or to a nearby surface water body if appropriate limits
can be met. The alluvial groundwater will be monitored to insure
that chemicals of concern decrease to cleanup levels. If natural
attenuation does not progress at a rate to meet cleanup levels
within the timeframe of active treatment to the surficial
aquifer, the remedial design will be modified to include active
treatment of alluvial as well as surficial groundwater.
An installed network of extraction wells and french drains will
extract contaminated groundwater from the surficial aquifer for
on-site treatment. The treatment system will use a biotreatment
process and sand/activated carbon filtration to treat more
heavily contaminated groundwater. After concentrations decrease
the system may be adjusted to reduce the rate of extraction or to
a point where only the filtration system is required. The
groundwater may also contain contaminants which may not be
effectively treated using a biotreatment process. These
contaminants may require a supplemental treatment step. Residual
constituents in the biotreatment sludges or spent carbon would be
disposed of off-site at an approved facility.
It is predicted that 12 million gallons of surficial groundwater
must be treated to reduce concentrations to cleanup levels. The
groundwater cleanup time frame is estimated to be 7 years. The
time may be shortened by putting nutrients into the surficial
aquifer to enhance biodegradation.
This alternative would provide overall protection for any present
or future uses of the property. The estimated implementation
timeframe for this alternative is seven (7) years. The estimated
cost for this alternative is $7,002,562.
7.4 ALTERNATIVE No. 4 - RCRA Cap. Extraction of Surficial
Groundwater for On-site Treatment, and Groundwater
Monitoring for the Alluvial-Aquifer.
This alternative involves placement of a RCRA cap over the
eastern half of the apartment complex, extraction and on-site
treatment of the surficial groundwater and monitoring of the
alluvial aquifer. Construction of the RCRA cap will require the
demolition of approximately six buildings and the capped area
would be fenced. As part of this alternative, the contaminated
surficial groundwater will be extracted in order to prevent
further migration of contamination. Groundwater will be treated
on-site and subsequently discharged. The integrity of the cap
would be maintained indefinitely with monitoring of the surficial
and alluvial aquifer. Surficial groundwater extraction and
treatment is expected to reduce contaminant concentrations below
63
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cleanup levels within eleven (11) years. The estimated cost for
this alternative is $3,870,460.
7 .5 ALTERNATIVE No. 5 - Concrete Cap. Extraction and Off-Site
Treatment and Disposal of Surficial Groundwater and
Monitoring of the Alluvial Acruifer.
This alterative consists of the placement of a concrete cap over
sections of the eastern half open grassy areas of the Redwing
Site,- surficial groundwater extraction with off-site treatment
and disposal and monitoring of the groundwater in the alluvial
aquifer.
The concrete cap would be constructed without the demolition of
any apartment buildings. The cap could be placed around the
existing apartment units which are in source areas of
contamination. The cap would be constructed such that its
integrity can be maintained and upward movement of subsurface
sludge would be inhibited.
The cap would be designed with sufficient thickness and joint
impermeability to control seeps of sludge and potential vapor
emissions. The cap would be designed and constructed above grade
over the current ground surface of the Redwing Site such that it
would eliminate migration of sludge around the edges of the cap.
The capped area would remain accessible for use by the apartment
residents. To maintain the existing functional use of the
Redwing Site, recreational-use improvements would be incorporated
into the cap design.
The contaminated surficial groundwater would be extracted and
treated on-site, as necessary, for disposal to the POTW.
Implementation of groundwater monitoring of the alluvial aquifer
and maintenance of the cap would be required. The estimated
timeframe for remediation of the surficial groundwater is ten
(10) years. Natural attenuation would be the mechanism for
remediation of the alluvial groundwater. The cap would be
maintained indefinitely. The estimated cost of this alternative
is $2,233,751.
7.6 ALTERNATIVE No 6 - Excavation of Source Material and
Surficial Groundwater with On-Site Treatment/Disposal.
Groundwater Monitoring of the Alluvial Aquifer.
This alternative combines source material excavation with on-site
treatment of source material and surficial groundwater.
Temporary relocation for approximately 2 years would be required
during excavati'. - and treatment of the source material.
Currently, the 3 no evidence that contamination exists under
the buildings. //ever, if contamination is found during the
64
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remedial design appropriate action, which may involve the
demolition of some buildings, will be undertaken. EPA will
consult the public before taking this action.
The following primary on-site treatment processes will be
implemented: 1) soil washing/flushing, 2) filtration, and 3)
biotreatment. The excavated source material will be stockpiled
and washed with a compatible washing agent as a volume reducing
treatment step. The washed soil would be then dewatered and
analyzed before backfilling into the excavation. The spent wash
solution and soil fines would be pumped through a filtration
system to further separate and concentrate the dissolved and
suspended constituents. The filtrate may be reused as wash
solution. The filtered constituents will then be sent to the
biotreatment unit. The biotreatment process will be designed to
create a favorable environment for microorganisms which are
capable of degrading the compounds of concern at the Redwing
Site.
In addition to the soil washing, other technologies (ex-situ soil
flushing, gravity separation and ex-situ bioremediation) may also
be used in addition to or instead of ex-situ -soil washing, if
during the remedial design these technologies are effective in
^reducing soil contaminant concentrations and are determined to be
cost effective.
Alternative 6 also includes extraction and active treatment of
surficial groundwater. Under this alternative, contaminated
groundwater would be extracted, treated on-site and discharged to
the POTW or to a nearby surface waterbody if appropriate limits
can be met. The alluvial groundwater will be monitored to insure
that chemicals of concern decrease to cleanup levels. If natural
attenuation does not progress at a rate to meet cleanup levels
within the timeframe of active treatment to the surficial
aquifer, the remedial design will be modified to include active
treatment of alluvial as well as surficial groundwater.
An installed network of extraction wells and french drains will
extract contaminated groundwater from the surficial aquifer for
on-site treatment. The treatment system will use a biotreatment
process and sand/activated carbon filtration to treat more
heavily contaminated groundwater. After concentrations decrease
the system may be adjusted to reduce the rate of extraction or to
a point where only the filtration system is required. The
groundwater may also contain contaminants which may not be
effectively treated using a biotreatment process. These
contaminants may require a supplemental treatment step. Residual
constituents in the biotreatment sludges or spent carbon would be
treated prior to disposal.
It is predicted that 12 million gallons of surficial groundwater
must be treated to reduce concentrations to cleanup levels. The
65
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groundwater" cleanup time frame is estimated to be 7.1 years. The
time may be shortened by putting nutrients into the surficial
aquifer to enhance biodegradation.
The estimated timeframe for treatment of the source material and
groundwater is 2 and 7 years respectively. The estimated cost of
this alternative is $6,168,452.
7.7 ARARS AND TBCS
The remedial action for the Redwing Site, under CERCLA Section
121 (d) , must comply with federal and state environmental laws
that are either applicable or relevant and appropriate (ARARs).
Applicable requirements are those standards, criteria or
limitations promulgated under federal or state law that
specifically address a hazardous substance, pollutant,
contaminant, remedial action, location or other circumstance at a
CERCLA site. Relevant and appropriate requirements are those
that, while not applicable, still address problems or situations
sufficiently similar to those encountered at the site that their
use is well suited to the particular site. To-Be-Considered
Criteria (TBCs) are non-promulgated advisories and guidance'that
are not legally binding but should be considered in determining
the necessary level of cleanup for protection of health or the
environment.
While TBCs do not have the status of ARARS, EPA's approach to
determining if a remedial action is protective of human health
and the environment involves consideration of TBCs along with
ARARs.
The affected groundwater in the aquifers beneath the Redwing Site
have been classified as Class IIB for the surficial groundwater
and Class IIA for the alluvial aquifer. Class IIB groundwater is
a potential drinking watei source althoug.. the groundwater may
not be currently used as such.' Class IIA groundwater is a
current source of drinking water. It is EPA's policy that
groundwater resources be protected and restored to their
beneficial uses. The six remedial alternatives with the
exception of alternative one (no action) have components which
may to some degree promote the beneficial use of the aquifers. A
complete definition for groundwater classification is provided in
the Guidelines for Ground-water Classification under the EPA
Ground Water Protection Strategy. Final Draft, December 1986.
The action level for lead in groundwater (IS^ig) is the only TBC
that has been identified at this time. The potential action
specific, chemical s --rific and State ARARs are presented in .
Tables 21A, B and C.
66
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TABLE 21A -
ACTION-SPECIFIC FEDERAL ARARS FOR THE REDWING
SITE
CLEAN WATER ACT - 33 U. S. C. 1251-1376
R & A
40 CFR Part 122, 125 -
National Pollutant
Discharge Elimination
System
Requires permits for the
discharge of pollutants for any
point source into waters of the
United States.
40 CFR Part 403 - National
Pretreatment Standards
Sets standards to control
pollutants which pass through or
interfere with treatment
processes in public treatment
works or which may contaminate
sewage sludge.
RESOURCE CONSERVATION AND RECOVERY ACT - 42 D.S.C. 6901-6987
R & A
40 CFR Part 257 - Criteria
for Classification-of
Solid Waste Disposal
Facilities and Practices
Establishes criteria for use in
determining which solid waste
disposal facilities and
practices pose a reasonable
probability of adverse effects
on public health or the
environment.
R & A
40 CFR Part 262 -
Standards Applicable to
Generators of Hazardous
Waste
Establishes standards for
generators of hazardous wastes
40 CFR Part 263 -
Standards Applicable to
Transportation of
Hazardous Waste
Establishes standards which
apply to transporters of
hazardous waste within the U.S.
if the transportation requires a
manifest under 40 CFR PaRt 262.
R & A
40 CFR Part 264 -
Standards for Owners and
Operators of Hazardous
Waste Treatment, Storage
and Disposal (TSD)
Facilities
Establishes minimum-national
standards which define the
acceptable management of
hazardous wastes for owners and
operators of facilities which
treat, store or dispose of
hazardous wastes.
40 CFR Part 268 - Land
Disposal
Identifies hazardous wastes that
are restricted from land
disposal and describes those
circumstances under which an
otherwise prohibited waste may
be land disposed.
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TABLE 21A -
ACTION-SPECIFIC FEDERAL ARABS FOR THE REDWING
SITE
SAFE DRINKING WATER ACT
40 CFR Parts 144 - 147
Underground Injection
Control Regulations
Provides for protection of
underground sources of drinking
water
HAZARDOUS MATERIALS TRANSPORTATION ACT - 49 U.S. C 1801-1813
40 CFR Parts 107,%171-177
- Hazardous Materials
Transportation Regulations
Regulates transportation of
hazardous materials.
A. = APPLICABLE REQUIREMENTS WHICH WERE PROMULGATE? UNDER FEDERAL LAW TO SPECIFICALLY ADDRESS A HAZARDOUS SUBSTANCE,
POLLUTANT, CONTAMINANT, REMEDIAL ACTION LOCATION C- THER CIRCUMSTANCE AT THE REDWNC SITE.
R b A. * RELEVANT AND APPROPRIATE REQUIREMENTS WHO- MOLE THEY ARE NOT 'AT 'UCABLE" TO A HAZARDOUS SUBSTANCE. POLLUTANT,
CONTAMINANT, REMEDIAL ACTION. LOCATION, OR OTHER CIRCUMSTANCE AT THE RED WNC SITE, ADDRESS PROBLEMS OR SITUATIONS SUmdlXTVt
SIMILAR TO THOSE ENCOUNTERED AT THE REDWING SITE THAT THEIR USE IS WELL SUITED TO THE SITE.
TABLE 21B - CHEMICAL-SPECIFIC FEDERAL ARARS FOR THE REDWING
SITE
CLEAN WATER ACT - 33 U. S. C. 1251-1376
R & A
A
40 CFR Part 131 - Ambient
Water Quality Criteria
requirements
40 CFR Part 403 - National
Pretreatment Standards
Suggested ambient standards for
the protection of human health
and aquatic life.
Sets standards to control
pollutants which pass through or
interfere with treatment
processes in publicly-owned
treatment works or which may
contaminate sewage sludge.
RESOURCE CONSERVATION AND RECOVERY ACT - 42 U.S.C. 6901-6987
R & A
40 CFR Part 261 -
Identification and Listing
of Hazardous Wastes
Defines those solid wastes which
are subject to regulation as
hazardous wastes under 40 CFR
Parts 263-265 and Parts 124,
2~0, and 271.
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TABLE 218 - CHEMICAL-SPECIFIC FEDERAL ARARS FOR THE REDWING
SITE
R & A
40 CFR Part 262 -
Standards Applicable to
Generators of Hazardous
Waste
Establishes standards for
generators of hazardous waste.
CLEAN AIR ACT - 42 USC Section 7401 - 7642
R & A
40 CFR Part 50 - National
Primary and Secondary
Ambient Air Quality
Standards
Establishes standards for
ambient air quality to protect
public health and welfare.
SAFE DRINKING WATER ACT - 40 USC Section 300
R & A
R & A
40 CFR Part 141 - National
Primary Drinking Water
Standards
PL No. 99-339 100 Stat.462
(1986) - Maximum
Contaminant Level Goals
(MCLGs)
Establishes maximum contaminant
levels (MCLs) which are health-
based standards for public water
systems .
Establishes drinking water
quality goals set at levels of
no known or anticipated adverse
health effects with an adequate
margin of safety.
A = APPLICABLE REQUIREMENTS WHICH WERE PROMULGATED UNDER FEDERAL LAWTO SPECIFICALLY ADDRESS A HAZARDOUS SUBSTANCE.
POLLUTANT, CONTAMINANT, REMEDIAL ACTION LOCATION OR OTHER CIRCUMSTANCE AT THE REDWING SITE.
R fr A = RELEVANT AND APPROPRIATE REQUIREMENTS WHICH WHttE THEY ARE NOT "APPL/CABLE" TO A HAZARDOUS SUBSTANCE, POLLUTANT.
CONTAMINANT, REMEDIAL ACTION, LOCATION. OR OTHER CIRCUMSTANCE AT THE RED WNC SITE, ADDRESS PROBLEMS OR SITUATIONS SUFFICIENTLY
SIMILAR TO THOSE ENCOUNTERED AT THE REDWING S/TE THAT THEIR USE IS WELL SUITED TO THE SITE.
TABLE 21C -STATE OF ALABAMA ARARS FOR THE REDWING SITE
REGULATION
APPLICABLE OR
RELEVANT AND
APPROPRIATE
BASIS FOR
DETERMINATION
Alabama Water Pollution
Control Act code of
Alabama, Title 22,
Chapter 22 - Water
Improvement Commission)
APPLICABLE REQUIREMENT WHICH WAS
PROMULGATED BY THE STATE OF
ALABAMA TO SPECIFICALLY ADDRESS A
HAZARDOUS SUBSTANCE, POLLUTANT,
CONTAMINANT. REMEDIAL ACTION
LOCATION OR OTHER CIRCUMSTANCE
AT THE REDWING SITE.
Establishes
standards for
limits of
pollution and
quality of water.
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TABLE 21C -STATE OP ALABAMA ARARS FOR THE REDWING SITE
Alabama National
Pollutant Discharge
Elimination System
Permit Regulations
(Alabama Administrative
Code, Department of
Environmental
Management, Water
Division, Water Quality
Program, Chapter 335-6-
6 NPDES; adopted
October 19, 1979;
amended January 24,
1989 v-
Alab -a Primary
Dri. _:ig Water
Sta:. .^rds (Alabama
Administrative Code,
Department of
Environmental
Management, Water
Division - Water supply
Program, Chapter 335-7-
2-Primary Drinking
Water Standards;
Adopted January 4,
1989)
APPLICABLE REQUIREMENT WHICH WAS
PROMULGATED BY THE STATE OF
ALABAMA TO SPECIFICALLY ADDRESS A
HAZARDOUS SUBSTANCE. POLLUTANT,
CONTAMINANT. REMEDIAL ACTION
LOCATION OK OTHER CIRCUMSTANCE
AT THE REDWINC SITE.
State
administered
permit program
comparable to the
National
permitting
system.
APPLICABLE REQUIREMENT WHICh
PROMULGATED BY THE STATE OF
ALABAMA TO SPECIFICALLY ADDRL
HAZARDOUS SUBSTANCE. POLLUTE.
CONTAMINANT. REMEDIAL ACTION
LOCATION OR OTHER CIRCUMSTANCE
AT THE REDWINC SHE.
Applicable to
water systems
required to
monitor for
various
contaminants.
Maximum Concentration
of Constituents for
Groundwater Protection
(Alabama Administrative
Code, Department of
Envi ronment a1
Management, Hazardous
Waste Program, Chapter
335-14-5.06-Releases
from Solid Waste
Management Units;
adopted June 8,m 1983;
amended January 25,
1992)
RELEVANT AND APPROPRIATE
REQUIREMENT WHICH WHILE IT IS NOT
APPLICABLE ' TO A HAZARDOUS
SUBSTANCE, POLLUTANT,
CONTAMINANT, REMEDIAL ACTION.
LOCATION, OR OTHER CIRCUMSTANCE
AT THE REDWINC SITE. ADDRESS
PROBLEMS OR SITUATIONS
SUmaiNTVf SIMILAR TO THOSE
ENCOUNTERED AT THE REDWINC SITE
THAT THEIR USE IS WELL SUITED TO
THE SITE.
Applies to
owners/operators
of facilities
that transport,
store, or dispose
of hazardous
waste.
8.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
This section of the ROD provides the basis for determining which
70
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alternative provides the best balance with respect to the
statutory balancing criteria in Section'121 of CERCLA, 42 U.S.C.
Section 9621, and in the NCP, 40 C.F.R, Section 300.430. The
major objective of the FS was to develop, screen and evaluate
alternatives for the remediation of the Redwing Site. A wide
variety of alternatives and technologies were identified as
candidates to remediate the contamination at the Redwing Site.
These were screened based on their feasibility with respect to
the contaminants present and the site characteristics. After the
initial screening, the remaining alternatives/technologies were
combined into potential remedial alternatives and evaluated in
detail. The remedial alternative was selected from the screening
process using the following nine evaluation criteria:
Overall protection of human health and the environment;
Compliance with applicable and/or relevant 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
implementation;
Implementability, 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, including additional costs should it fail;
Acceptance by the State and
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;
(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
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(3) Modifying Criteria - state and community acceptance are
modifying criteria that are formally taken into account
after public comments are received on the proposed plan and
incorporated in the ROD.
The selected alternative must meet the threshold criteria 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 is the technical criteria upon which the
detailed analysis of alternatives 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 Redwing Carriers Inc.,
(Saraland) Superfund Site under each of the criteria. A
comparison is made between each of the alternatives for
achievement of a specific criterion.
8.1 THRESHOLD CRITERIA
Overall Protection of Human Health and the Environment
Each of the alternatives with the exception of Alternative 1 and
2 would provide protection of human health and the environment by
minimizing or controlling the risk associated with the
contaminated soils through institutional controls and treatment
or containment. Alternative 2 would rely on an ongoing
maintenance endeavor to achieve satisfactory protection from
direct contact with the source material, but is ineffective for
protection of groundwater. Therefore, cleanup levels for
groundwater would not be achieved with Alternative 2. The
containment alternatives 4 and 5 would rely on continued
maintenance to achieve satisfactory protection. These two
alternatives provide overall protection by isolating the source
material from potential direct contact, ingestion or inhalation.
The surficial groundwater pump and treat action may eventually
achieve the remedial objective for the surficial groundwater,
however, the source material would remain. Therefore, overall
protection may not be achieved with alternatives 4 and 5. Those
alternatives involving excavation, (Alternatives 3 and 6), would
minimize the"majority of the risk by removing and treating the
principal source of the soil and groundwater contamination.
Alternatives 3 and 6 would provide the best overall protection
because of removal and treatment of contaminated soils and
groundwater.
Compliance with ARARs
72
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Each of the remaining alternatives (alternatives 3,. 4, 5 and 6)
could comply with all Federal or State ARARs or justify a waiver.
Chemical specific ARARs for groundwater would be met through
compliance with the groundwater protection standards (ie., MCLs).
8.2 PRIMARY BALANCING CRITERIA
Long-Term Effectiveness and Permanence
The long-term effectiveness is demonstrated by treatment of
contaminated soils and groundwater using proven technologies thus
eliminating potential exposure and long term maintenance.
Alternatives 3, 4, 5 and 6 would provide long-term effectiveness
through limiting the migration of contamination or treatment of
the contaminated soils at the Redwing Site'. For alternatives 4
and 5, long-term effectiveness relies on proper cap maintenance
and continued extraction and treatment of groundwater.
Implementation would require restricted use of the affected
groundwater until the remedial cleanup goals are achieved. In
Alternative 4, the contaminants are contained on-site in a RCRA
landfill while Alternative 5 uses a concrete cap to prevent
infiltration of rainwater into the contaminated soils. The
long-term effectiveness of Alternative 4 and 5 is satisfactory
since continuous inspection and monitoring would be required
while allowing for the use of the property as an apartment
complex. Alternatives 3 and 6 provide the best level of
long-term effectiveness because treatment would be utilized to
permanently remediate the soils and groundwater.
Reduction of Toxicity, Mobility or Volume Through Treatment
Alternatives 4 and 5 would isolate the contamination from the
environment thus minimizing the forces which drive contaminant
mobility. However, toxicity and volume would not be affected by
Alternative 4 or 5. Alternatives 3 and 6 would reduce the
mobility, toxicity, and volume of contaminants which are above
acceptable risk levels.
Short-Term Effectiveness
Alternatives 3, 4, 5 and 6 will require varying amounts of time
to implement. None are immediately implementable or effective.
Threshold toxicity criteria would not be exceeded by implementing
Alternatives 3 and 6. Health risks to remedial workers is
unlikely since appropriate monitoring and engineering controls
will be applied. Of the alternatives evaluated, Alternatives 3
and 6 are most effective because contaminated soils and
groundwater would be removed and treated. However Alternative 6
would require a longer implementation time period because of the
requirement for on-site treatment, thus reducing its short term
73
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effectiveness.
Xmplementability
Alternatives 3, 4, 5 and 6 are equally implementable but may
require the temporary/permanent relocation of on-site residents
to allow for excavation and construction. Alternative 4 may
require permanent demolition of the on-site buildings located in
the capped area. Complexities in the implementation of
alternatives 3, 4 and 6 exist because remediation impacts on the
apartment complex residents. Alternative 5 (Concrete Cap) design
would be complex to allow for the continued use of the property
as a pleasant living environment.
Cost
All of the alternatives which involve on-site treatment
components have higher capital and present worth cos- . However,
the cost associated with Alternatives 3 and 6 (exca- ion with
on-site/off-site treatment) would not extend into th . operation
and maintenance period except for a limited time to achieve the
groundwater cleanup goals. Alternatives 4, and 5 would require
expenditure of funds for an indefinite period of time.
Cost Summary
Since no action would be taken under alternative 1, no additional
costs would be incurred. The other alternatives range in cost as
shown below. Temporary relocation costs are not included in cost
estimates for alternatives 3 and 6. Capital costs include direct
and indirect costs. Operation and Maintenance costs are present
worth dollars based on 5% discount rate. Implementation present
worth is the sum of capital cost3 and the present worth of the
total Operation and Maintenance expenditures.
Alternative Capital Cost O&M Costs Present Worth Costs
2 $ 76,000 $ 482,000 $ 558,000
3 $6,484,763 $ 518,000 $7,002,562
4 $2,065,755 $1,805,000 $3,870,000
5 $1,811,017 $ 423,000 $2,233,751
6 $5,951,165 $ 217,000 $6,168,000
8.3 MODIFYING CRITERIA
State Acceptance
The State of Alabama has concurred with the selection of
Alternative 3 to remediate the Redwing Site. The State of
Alabama expressed concern that the originally proposed
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Alternative 6 would not be the appropriate option for the Redwing
Site. EPA took the state agency's concern into account and
reevaluated the preferred alternative.
Community Acceptance
At the August 11, 1992 public meeting the primary concern
expressed by the community was that the sludge and contaminated
materials be removed from the Redwing Site. Implementation of an
off-site option (Alternative 3) will provide a protective
remedial alternative and satisfy the primary community concern.
9.0 THE 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 source control and groundwater
remedy for this site. The risk associated with this site has
been calculated at 10"6 at the completion of this remedy. This
is determined to be protective of human health and the
environment. The total present worth cost of the selected
remedy, Alternative #3, is estimated at $7,002,562.
A. Source Control
Source control remediation will address the contaminated soils,
sludges and sediments at the Site. Source control shall include
excavation of soils, sludges and sediments, staging, dewatering,
characterization, and transportation to an approved disposal
facility.
A.I. The manor components of source control to be implemented
include:
Soils, sludges and related materials shall be excavated
at the Redwing Site and staged on-site for off-site
disposal. Excavation shall occur in all areas of site
related contamination above cleanup levels. The concrete
liners in the southern and eastern ditches shall be
removed and excavation shall occur along past and present
drainage pathways from the Redwing Site. Excavation
shall continue until the remaining soils and sediments
material achieve the levels specified in the tables
below.
In order to comply with ARARs, source material may
require pre-treatment prior to disposal. This may
require thermal treatment of soils. Excavated subsurface
soils may require dewatering and stabilization prior to
land disposal. The water from the saturated soils must
be analyzed and treated/disposed of in an appropriate
75
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manner.
Excavation may be accomplished with or without the
removal of buildings or structures. While the areas of
soil and sludge (i.e. source material) are excavated
residents will be temporarily relocated. Source
materials will be excavated and moved to a staging area
on-site prior to being hauled off-site. Some of the
excavated soils will be removed from the saturated zone
and will require dewatering. Sidewalk slabs and pavement
areas may be contaminated and thus require removal.
Excavated areas will be backfilled with clean material.
The excavated material will be sorted and characterized
to determine if treatment is required before land
disposal. If treatment is required it will be conducted
off-site at an approved facility. All excavated soil,
source material, sludge, and contaminated debris will be
disposed of off-site at an approved facility.
Excavation of the surface soils and along the drainage
pathways shall continue until the levels identified in
the table below are met.
TABLE 22A SURFACE SOIL AND SEDIMENT
EXCAVATION LEVELS
CONTAMINANT
BENZO (A) PYRENE
BENZO (B) FLUORANTHENE
BENZO (A) ANTHRACENE
CARBON TETRACHLORIDE
CHRYSENE
EXCAVATION
LEVEL
(jig/kg)
94.9
540
1,025
9,590
362
Excavation of materials shall occur in the subsurface
soils contaminated with chemical concentrations above the
levels identified in the table below*:
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TABLE 22B SUBSURFACE SOIL EXCAVATION LEVELS
CONTAMINANT
4,4' -DDT
ACETONE
ALDRIN
ALPHA -BHC
CHLOROFORM
CHROMIUM
DIELDRIN
GAMMA- BHC (LINDANE)
METHYLENE CHLORIDE
NICKEL
VANADIUM
VERNOLATE
EXCAVATION
LEVEL
(jig/kg)
566
36
4
0.5
70
47,000
0.1
3.2
0.6
30,000
156,000
55
If lead is detected in subsurface soils not
already cited for remediation because the cleanup
levels above have been exceeded, and the
concentration of lead is greater than 54j 00Dug/kg;
then groundwater and soil characterization will be
conducted to determine if soil cleanup is required
for the protection of groundwater at 15|ag/l, the
current action level for lead in groundwater.
A.2 Treatment of excavated material
The excavated material will be sorted and characterized
for RCRA hazardous waste characteristics, to determine if
thermal or other treatment is required before land
disposal. If treatment is required it will be conducted
off-site at an approved facility.
A.3 . Performance Standards
The performance standards for this component of the
77
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selected remedy include, but are not limited to, the
following excavation and treatment standards:
a. Excavation Standards:
Excavation shall continue until the remaining soil and
material achieve the concentration levels identified in
Table 22A and 22B of the previous section. All
excavation shall comply with ARARs, including, but not
limited to OSHA and state standards. Testing methods
approved by EPA shall be used to determine if the
concentration levels have been achieved.
b. Treatment Standards:
. -1 excavated soils, sludges and related materials will
cisposed of at an appropriate approved facility. Pre-
treatment may be required prior disposal. Treatment
will be conducted at an approved facility.
B. Groundwater Remediation
Groundwater remediation will address the contaminated groundwater
at the Redwing Site. Contaminated surficial groundwater will be
extracted, treated on-sife and discharged to the POTW or to a
nearby surface waterbody if the POTW is unavailable and if
appropriate limits can be met. The alluvial groundwater will be
monitored to insure that chemicals of concern decrease to cleanup
levels. If natural attenuation does not progress at a rate to
meet cleanup levels within the timeframe of the active treatment
of the surficial groundwater, the remedial design will be
modified to include active treatment of the alluvial aquifer as
well as surficial groundwater.
B.I. The ma-jor components of qroundwater remediation to be
implemented include:
Extraction and active treatment of the surficial
groundwater. The major component of groundwater
remediation to be implemented at the Redwing Site is
installation of a network of extraction wells and french
drains to extract contaminated groundwater from the
surficial aquifer for on-site treatment with discharge to
a POTW or to a nearby surface waterbody if appropriate
limits can be met.
B.2. Extraction, Treatment, and Discharge of Contaminated
Groundwater
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The treatment system will use a biotreatment process and
sand/activated carbon filtration to treat heavily
contaminated groundwater. After concentrations decrease
(estimated at 1,000,000 gallons), the system may be
adjusted to reduce the rate of extraction or where only
the filtration system is required. The groundwater may
also contain contaminants which will not be effectively
treated using a biotreatment process. These contaminants
may require a supplemental treatment step as identified
during the remedial design. Residual constituents in the
biotreatment sludges or spent carbon will be disposed of
at an approved facility.
It is predicted that approximately 12 million gallons of
surficial groundwater must be treated to reduce
concentrations to cleanup levels which are specified in
Table 20 of this ROD and repeated in Section B.3 below.
The groundwater cleanup time frame is estimated to be 7
years. The time may be shortened by putting nutrients
into the surficial aquifer to enhance biodegradation.
B.3. Performance Standards
Groundwater shall meet the clean-up levels specified in
the table below at the wells in the surficial and
alluvial aquifers at the Redwing Site.
a. Extraction Standards:
Groundwater will be extracted from the surficial
aquifer in a. manner to be determined during the
remedial design.
b. Treatment Standards:
Groundwater shall be treated until the cleanup levels
identified below are attained at the wells designated
by EPA as compliance points:
CONTAMINANTS OF
CONCERN
4,4'-DDT
ACETONE
ALDRIN
GROUNDWATER
CLEANUP
LEVEL
(Liq/1) *
0.158
1,120
0.00317
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CONTAMINANTS OF
CONCERN
ALPHA-BHC
BERYLLIUM
BIS(2-ETHYLHEXYL)PHTHALATE
CARBON DISULFIDE
CHLOROFORM
CHROMIUM
DIELDRIN
GAMMA - BHC (LINDANE)
METHYLENE CHLORIDE
NICKEL
VANADIUM
VERNOLATE
GROUNDWATER
CLEANUP
LEVEL
(Uq/1) *
0.00855
4.00
6.00
47.6
100
50
.00337
0.2
5
100 .
78.1
11.2
* Based on MCL or Risk Assessment
c. Discharge Standards:
Discharges for the groundwater treatment system shall
comply with all ARARs, including, but not limited to,
POTW pretreatment requirements, substantive
requirements of the NPDES permitting program under the
Clean Water Act, 33 U.S.C Section 1251 et sea., and all
effluent limits established by EPA.
d. Design Standards:
The design, construction and operation of the
groundwater treatment system shall be conducted in
accordance will all ARARs, including the RCRA
requirements set forth in 40 C.F.R. Part 264 (Subpart
F) .
C. Compliance Monitoring
Groundwater monitoring shall be conducted at this site on a
monthly basis at wells designated by EPA as compliance points.
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After demonstration of compliance with Performance Standards, the
Site including soil and groundwater shall continue to be
monitored quarterly for five years. Inspection of surface soils
for sludge seeps shall occur not less than monthly during the
summer months of the year. If monitoring indicates that the
Performance Standards set forth in Paragraph B.3 are being
exceeded at any time after pumping has been discontinued,
extraction and treatment of the groundwater will recommence until
the Performance Standards are once again achieved. If monitoring
of the remaining soil indicates Performance Standards set forth
in Paragraph A.3 have been exceeded, the effectiveness of the
source control component will be re-evaluated.
10.0 STATUTORY DETERMINATIONS
The selected remedy satisfies the requirement of CERCLA section
121 to protect human health and the environment by eliminating
and by reducing risks posed through each pathway and population
through treatment. The remedy ensures adequate protection of
human health and the environment. The site risk will be reduced
to the 10"6 risk range for carcinogens, and a Hazard Index for
non-carcinogens of less than one.
No short-term risks or cross-media impacts will be caused by
implementation of the remedy. The selected remedy satisfies the
requirement of CERCLA section 121 to comply with ARARS.
The selected remedy provides overall effectiveness proportionate
to its costs (i.e., is cost-effective). The selected remedy
satisfies the requirement of CERCLA section 121 to utilize
permanent solutions and alternative treatment technologies or
resource recovery technologies to the maximum extent practicable.
The selected remedy provides the best balance of tradeoffs among
the alternatives with respect to the evaluation criteria. Those
criteria that were most critical in the selection decision (i.e.,
those criteria that distinguish the alternatives most) are:
Overall protection of human health and the environment,
compliance with ARARs; reduction of toxicity, mobility and volume
through treatment; long term effectiveness and permanence; state
and community acceptance.
11.0 DOCUMENTATION OF SIGNIFICANT CHANGES
Significant changes from the Proposed Plan must be documented in
accordance with CERCLA section 117(b). Although the changes from
the originally proposed remedial alternative are significant they
could have been reasonably anticipated by the public based on the
alternatives and other information available in the proposed plan
and the supporting analysis and information in the administrative
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record. Therefore, no additional public comment on the revised
remedial alternative will be offered.
The State of Alabama indicated grave concern about the on-site
treatment aspect of Alternative 6. This was due to the density
of the population in close proximity to the on-site treatment of
contaminated soils. The Region evaluated the State's concerns
with great scrutiny and agreed that the selection of Alternative
3 provided for a better balance between the preference for on-
site treatment, and the concerns for the overall negative effect
on the community. Alternative 3 has therefore been selected as
±he final remedial alternative for the Redwing Site.
The soil clean-up levels protective of ground water generated by
Redwing Carriers Inc., in the Draft Feasibility Study Report and
subsequently put-forth in the Proposed Plan, were reviewed and
revised. Redwing used the SUMMERS model to generate the levels
and one correction was necessary for each compound. Redwing
incorrectly calculated the octanol/water partitioning coefficient
.(Koc) because they used an equation that is specific to only
certain compounds. EPA recalculated the soil clean-up levels
using compound specific Koc values from the EPA publication
entitled Basics of Pump-and-Treat Ground Water Remediation
'Technology. Table 18 reflects the results of these
calculations.
Redwing did not use a site specific partitioning coefficient to
determine the soil cleanup level for lead. It was determined
that site specific values should be used. EPA performed a
statistical analysis of site specific soil/water partitioning
coefficients (Kd's) generated for the site rather than use the Kd
that was used before. The cleanup level which was obtained for
lead using this site specific Kd can been specified as an action
level for further characterization of soil and groundwater in
areas where cleanup levels for other constituents of concern have
not been exceeded.
Although some of the cleanup levels contained in the Draft
Feasibility Study were computed incorrectly they were calculated
to achieve the remediation goals which would result in acceptable
exposure levels that are protective of human health and the
environment. The result of EPA's recalculation of the cleanup
levels was that some of the levels became higher while others
became lower, however, the final remediation goal remains the
same. In the case of the subsurface soil cleanup levels,
protection of the qroundwater AB a potential drinking water
source is the final remediation goal. A comparison of the
cleanup levels from the Draft Feasibility Study and EPA's
recalculated values, is presented below:
82
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SOIL CLEAN-UP LEVELS PROTECTIVE OF GROUND WATER
(all cleanup levels are in units of ug/ka)
Compound
DDT
Acetone
Aldrin
A-BHC
Chloroform
Chromium
Dieldrin
G-BHC (Lindane)
Methylene Chloride
Nickel
Vanadium
Vernolate
Proposed Plan
Cleanup Level
131
295
0.860
0.402
419
85,800
0.0959
9.40
9.05
30,300
157,000'
56.0
ROD Cleanup
Level
566
36
4
0.5
70
47,000
0.1
3.2
0.6
30,000
156,000
55.0
83
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APPENDIX B:CONCURRENCE LETTERS
XIV
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IVL
Leigh Pegues. Director
1751 Cong.W.L.
Dickinson Drive
Montgomery. AL
36130
(205)271-7700
FAX 271-7950
270-5612
Field Offices.
110 Vulcan Road
Birmingham. AL
3S209
(205)942-6166
FAX 941-1603
P.O. Box 9S3
Oecatur, AL
35602
(205)353-1713
FAX 340-9359
2204 Perimeter Road
Mobile. AL
3661S
(205)450-3400
FAX 479-2593
ALABAMA
DEPARTMENT OF ENVIRONMENTAL MANAGEMENT
Guy Hunt
Governor
November 30,
Mr. Kenneth A. Lucas, RPM
U.S. EPA, SSRB
345 Courtland St. N.E.
Atlanta, GA 30365
Re: Redwing Carriers/Sarland Apartments NPL Site
Record of Decision
Dear Mr. Lucas:
The Alabama Department of Environmental Management
(ADEM), Special Projects, received the second draft
Record of Decision (ROD) for the Redwing
Carriers/Saraland Apartments NPL Site on November 6,
1992, for review and requested concurrence.
This office appreciates the EPA's consideration of
STATE concerns expressed in correspondence and at our
September -29, 1992 meeting, with you and Mr. Arthur
Collins, here in Montgomery.
The STATE concurs with this ROD, but has
reservations that the selected remedy could be onerous
to implement. We reiterate the position that
protection of human health and the environment could
be accomplished with a less extensive and disruptive
alternative.
Confirmation of the presence or absence of source
material beneath buildings can be ascertained by use
of recently developed sensing equipment used in the
oil industry and discussed with you.
It is suggested that the clean-up level for
Methylene Chloride in subsurface soil and surficial
groundwater may be at or below detection limits.
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Page 2
Mr. Kenneth A. Lucas
November 30, 1992
In Section 7.3. page 63. 2nd paragraph, thermal
pre-treatment of source material and groundwater is
not understood. We see similar language in the draft
Scope of Work, received Wednesday, November 25, 1992.
Applicable air emission standards would have to be met
in the use of any thermal device.
Section 9.0 B.. page 80. Groundwater Remediation.
calls for discharge of treated water to be discharged
to the POTW or to a nearby surface waterbody. Except
for rain events, the closest waterbody is Norton
Creek, 1/2 mile from the site.
Please be advised that concurrence with this ROD
does not bind the STATE contractually to matching
requirements in the event of Fund .Lead remediation.
If this Lead is followed, the department would
approach the Legislature to request funds to meet the
fiscal matching requirements concerning this Site.
If there are questions, call this office at
(205)260-2787 or 260-2786.
Dahle^L E. Cooper,
Special Projects
/JEM/jdb
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