NCD062555792_20060601_Sigmons Septic Tank Service_FRBCERCLA FS_Final Feasibility Study Report OU-1-OCR

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FINAL
Feasibility Study Report
Sigmon's Septic Tank Site
Operable Unit 1
Statesville, North Carolina
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FINAL
Feasibility Study Report
Sigrnon's Septic Tank Site
Operable Unit 1
Statesville, Iredell County, North Carolina
Prepared for:
U.S. Environmental Protection Agency, Region 4
EPA Work Assignment No. 340-RICO-A44F
BVSPC Project No. 48340.0110
Prepared by:
Black & Veatch Special Projects Corp.
1145 Sanctuary Parkway, Suite 475
Alpharetta, Georgia 30004
June 2006
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Table of Contents
Section TOC
Revision No. I
June 2006
Page I of3
Page No.
1.0 Introduction ............................................................................................................................ 1-l
1.1 Objectives ........................................................................................................................ 1-2
1.2 Site Background .............................................................................................................. 1-4
1.2.1 Site Description ...................................................................................................... 1-4
1.2.2 Operational History ................................................................................................ 1-5
1.2.3 Regulatory History and Previous Investigations .................................................... 1-6
1.3 Nature and Extent of Contamination ............................................................................. I-I 4
1.3.1 SourceAreas ......................................................................................................... 1-14
1.3 .2 Downgradient Media ............................................................................................ 1-15
1.4 Contaminant Fate and Transport ................................................................................... 1-I 6
1.4.1 Soil-to-Groundwater Migration ............................................................................ 1-17
1.4.2 Soil-to-Surface Water/Sediment Migration .......................................................... 1-l 7
1.4.3 Groundwater-to-Surface Water Migration ........................................................... 1-17
1.5 Human Health Risk Assessment ................................................................................... 1-17
1.5.1 Contaminants of Concern ..................................................................................... 1-l 8
1.5.2 Exposure Scenarios and Receptors ...................................................................... 1-l 8
1.5.3 Toxicity Assessment ............................................................................................ 1-19
I . 5 .4 Risk Characterization ......................................................................................... 1-19
1.5.5 Remedial Goal Options ........................................................................................ 1-20
1.5 .6 Leachability Criteria for Groundwater COCs Present in Soils ............................ 1-22
1.6 Ecological Risk Assessment. ......................................................................................... 1-26
2.0 Identification and Screening of Technologies ........................................................................ 2-l
2.1 Basis for Remedial Action ............................................................................................... 2-l
2.2 Applicable or Relevant and Appropriate Requirements .................................................. 2-2
2.2.1 Chemical Specific Requirements ........................................................................... 2-3
2 .2.2 Location Specific Requirements ............................................................................. 2-3
2.2.3 Action Specific Requirements ................................................................................ 2-3
2.3 Remedial Action Objectives ............................................................................................ 2-3
2.3.1 Selection of Final Contaminants of Concern .......................................................... 2-4
2.4 General Response Actions and Estimated Volume of Contaminated Soil. ..................... 2-5
2.5 Compilation of Remedial Technologies and Process Options ........................................ 2-6
2.5. I Surface Soil ........................................................................................................... 2-6
2.5 .2 Subsurface Soil ...................................................................................................... 2-6
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Table of Contents
(Continued)
Section TOC
Revision No. 1
June 2006
Page2of3
Page No.
3 .0 Identification, Screening, and Evaluation of Technologies and Process Options ................. 3-1
3.1 General Response Actions ............................................................................................... 3-l
3.2 Preliminary Screening of Technologies and Process Options ......................................... 3-3
3.3 Evaluation of Retained Technologies and Process Options ............................................ 3-5
4.0 Development and Screening of Alternatives ........................................................................ .4-l
4.1 Soil Alternatives Analysis .............................................................................................. .4-l
4.1. I Alternative 1 -No Action ..................................................................................... .4-2
4.1.2 Alternative 2 -Excavation and Onsite Treatment with Solidification/
Stabilization, and Onsite Disposal of Treated Waste ............................................ .4-3
4.1.3 Alternative 3 -Excavation and Onsite Treatment with Solidification/
Stabilization and Offsite Disposal of Treated Waste ............................................ .4-5
4.2 Screening of Soil Alternatives for Further Evaluation ................................................... .4-7
4 .2.1 Effectiveness ......................................................................................................... .4-7
4.2 .2 Implementability .................................................................................................... .4-7
4.2.3 Cost ........................................................................................................................ .4-7
4.3 Selection of Soil Alternatives for Further Evaluation .................................................... .4-7
5.0 Detailed Analysis of Alternatives .......................................................................................... 5-l
5.1 Analysis of Soil and Sediment Alternatives .......................................................................... 5-5
5.1. 1 Alternative 1 -No Action ...................................................................................... 5-6
5.1.2 Alternative 2 -Excavation, Onsite Treatment with Solidification/
Stabilization, and Onsite Disposal of Treated Waste ............................................. 5-7
5.1.3 Alternative 3 -Excavation, Onsite Treatment with Solidification/
Stabilization, and Offsite Disposal of Treated Waste ............................................ 5-9
6.0 Comparative Analysis of Alternatives ................................................................................... 6-l
7 .0 References ............................................................................................................................ 7 -I
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Final Feasibility Study Report -Operable Unit l
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Table of Contents
(Continued)
Potential Chemical-Specific ARARs
Potential Location-Specific ARARs
Potential Action-Specific ARARs
Table of Applicable RGOs and Clean-up Criteria Selection
Section TOC
Revision No. I
June 2006
Page 3 of3
Tables
Table 2-1
Table 2-2
Table 2-3
Table 2-4
Table 3-1
Table 3-2
Table 3-3
Table 4-1
Table 5-1
Table 6-1
Initial Screening of Technologies and Process Options for Soils/Sediments
Evaluation of Process Options for Contaminated Soils and Sediments
Summary of Retained Technologies and Process Options -Contaminated Soil
Development of Remedial Action Alternatives for Soil
Figures
Figure 1-1
Figure 1-2
Figure 1-3
Figure 1-4
Figure 1-5
Figure 1-6
Figure 1-7
Figure 1-8
Figure 2-l
Summary of Soil Alternatives Evaluation
Comparative Analysis of Soil Alternatives
Site Vicinity Map
Site Location Map
Site Layout Map
Lead in Groundwater Samples
Mercury and Lead in Subsurface Soil Samples
Manganese in Groundwater Samples
Manganese in Subsurface Soil Samples
Mercury in Groundwater Samples
Area that Exceeds Site Cleanup Goals
Appendices
Appendix A Detailed Analysis Cost Estimation Worksheets
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Section A&A
Revision No. I
June 2006
Page I of2
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
ARAR
AWQC
Black & Veatch
bis
CERCLA
CFR
coc
COPC
DER
DOT
EPA
ES!
FS
GRA
HI-IRA
HI
HQ
µg/L
mg/kg
MCL
MEP
MITN
NCP
NCDEM
NCDENR
NCDNRCD
NCDSWM
O&M
OU
PA
PAI-I
Abbreviations and Acronyms
Applicable or Relevant and Appropriate Requirement
Ambient Water Quality Criteria
Black and Veatch Special Projects Corporation
below land surface
Comprehensive Environmental Response, Compensation Liability Act
Code of Federal Regulations
Contaminant of concern
Contaminants of Potential Concern
Data Evaluation Report
Department of Transportation
U.S. Environmental Protection Agency
Expanded Site Investigation
Feasibility Study
General Response Action
Human Health Risk Assessment
Hazard Index
Hazard Quotient
microgram per liter
milligram per kilogram
Maximum Contaminant Limit
Multiple Extraction Procedure
Mobility/Toxicity/Volume
National Contingency Plan
North Carolina Department of Environmental Management
North Carolina Department of Environment and Natural Resources
North Carolina Department of Natural Resources and Community
Development
North Carolina Department of Solid Waste Management
Operation and Maintenance
Operable Unit
Preliminary Assessment
Polycyclic Aromatic Hydrocarbon
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
PCB
PPE
PRG
RA
RAO
RAGS
RCRA
RID
RF!
RGO
RI
ROD
RTPO
SARA
SESD
SI
SLERA
sow
SQL
S/S
SSTS
svoc
TBC
TCE
TCLP
USGS
voe
Abbreviations and Acronyms
(Continued)
Polychlorinated Biphenyl
Primary Point of Entry
Preliminary Remediation Goal
Remedial Alternative
Remedial Action Objective
Risk Assessment Guidance for Superfund (Part D)
Resource Conservation and Recovery Act
Reference Dose
Remedial Field Investigation
Remedial Goal Option
Remedial Investigation
Record of Decision
Remedial Technology and Process Option
S uperfund Amendments and Reauthorization Act
EPA Sciences and Ecosystem Support Division
Site Investigation
Screening-level Ecological Risk Assessment
Statement of Work
Sample Quantitation Limit
So I id i fication/S tabilization
Sigmon's Septic Tank Service
Semi-volatile Organic Compound
To Be Considered
Trichloroethene
Toxicity Characteristic Leaching Procedure
U.S. Geological Survey
Volatile Organic Compound
Section A&A
Revision No. I
June 2006
Page 2 of2
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
1.0 Introduction
St:ction l
Revision No. I
June 2006
Page I of 26
Biack and Veatch Special Projects Corp. (Black & Veatch) was retained by the U.S.
Environmental Protection Agency (EPA) to perform a Remedial Investigation (RI)/Feasibility
Study (FS) for the Sigmon's Septic Tank Site (SSTS) Operable Unit (OU) I site located in
Statesville, Iredell County, North Carolina. The RI/FS process is authorized by the
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980
as amended by the Superfund Amendments and Reauthorization Act (SARA) of 1986 (i.e.,
Superfund program) for characterizing the nature and extent of contamination and evaluating
potential remedial options for risks to human health and the environment at uncontrolled
hazardous waste sites.
This FS report was prepared by Black & Veatch for EPA Region 4 under Work Assignment 340-
RICO-A44F in accordance with the RI/FS Statement of Work (SOW), dated May 7, 2001 (EPA,
2001a). It fulfills the requirements of Tasks 10, 11, and 12 of the EPA-approved Final RI/FS
Work Plan (Black & Veatch, 2002a). This report was written in accordance with the document
Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA
(Interim Final), Office of Solid Waste and Emergency Response Directive 9355.3-0 I (EPA,
1988). The FS represents one step in the remedy selection process under CERCLA. Following
completion of the FS, a Proposed Plan will be prepared that identifies the preferred Remedial
Alternative (RA). The Proposed Plan will be distributed for public review and comment.
Following a public comment period, a Record of Decision (ROD) will be prepared that identifies
the selected remedy.
The alternatives that are evaluated and recommended for selection in this FS represent a work in
progress that will continue to evolve and be refined based on reviewer feedback. Also, the RAs
presented in this report are not mutually exclusive choices and do not limit the choice of a final
remedy, which is not formalized until the ROD. Thus, a preferred alternative (as developed in
the Proposed Plan) or the selected remedy (as developed in the ROD) can mix the elements of
the various alternatives developed in the FS, refine or modify those elements, or add to them.
While the FS supplies information for helping select a remedy, information supplementing the
FS may be incorporated into the remedy selection process at any time .
Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
1.1 Objectives
Section l
Revision No. I
June 2006
Page 2 of 26
The primary objective of this FS is to develop an appropriate range of RAs for waste
management in soil (surface or subsurface), surface water, and sediment at the SSTS that will
protect human health and the environment, and which will meet applicable or relevant and
appropriate requirements (ARAR) for a site. Groundwater is not addressed as part of OU!.
Groundwater will be addressed under OU2 activities. A secondary objective of the FS is to
provide an opportunity for early input into: identification of Remedial Action Objectives
(RAOs); decisions regarding level of risk-based clean-up criteria for the site; development and
evaluation of General Response Actions (GRAs); and the preliminary RAs. In response to
stakeholder input, the development, screening and evaluation of RAs may be modified at any
time.
This FS consisted of the following steps:
• Early in the FS process, each interim remedial option is described and subjected to a
preliminary evaluation of effectiveness, -implementability, and cost consistent with EPA
guidance (EPA, 1988).
• This initial screening process eliminates a large number of interim options and results in a
more manageable number of viable options that are then organized into appropriate
combinations to create comprehensive RAs for the site. The RAs developed from the
interim remedial options that pass the screening process represent comprehensive, site-wide
alternatives, consistent with EPA guidance.
• Based on the results of the screening process, the options recommended for detailed
analysis in the FS are identified, and key issues for the detailed analysis are identified.
Later in the FS process, the comprehensive RAs are scrutinized more thoroughly in the
detailed analysis phase of the FS.
The RAs presented in this FS are not developed to a level of detail required to prepare a remedial
design or conduct a remedial action necessary to implement the remedy selected in the ROD;
remedial design and remedial action are post-ROD activities. Also, some uncertainty regarding
potential performance of the FS alternatives will remain after the detailed analysis has been
completed. Additional information may be collected subsequent to the FS, as needed to support
remedy selection or post-ROD remedial design/remedial action. The supplemental information
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section I
Revision No. l
June 2006
Page 3 of26
could consist of results obtained from additional site characterization or from treatability studies
designed to evaluate the effectiveness and performance of specific remedial technologies.
This FS Report consists of six main sections. Brief summaries of the remaining sections are
presented below:
■ Section 2 presents the ARARs and the objectives of remedial action at the site. The
objectives are developed to address the risks posed to human health and the environment by
the contamination found at the site. This section also discusses the remediation goals for the
media of concern, as well as the extent of contamination exceeding those goals.
■ Section 3 identifies GRAs that will satisfy the cleanup objectives for the SSTS. A wide
range of technologies and process options that are applicable to the response actions and site
characteristics are then identified and screened before assembly of remedial action
alternatives. The screening process focuses on eliminating those technologies and process
options that have severe limitations for a given set of waste-and site-specific conditions, as
well as inherent technology limitations.
■ Section 4 presents the formulation of remedial action alternatives which is the combination
of GRAs and process options chosen to represent the various technology types for each
medium of concern. A range of alternatives was assembled that result in differing levels of
site cleanup. These alternatives were developed and described in detail to facilitate
subsequent screening. The alternatives were then evaluated to determine their overall
effectiveness, implementability, and cost. Alternatives with the most favorable overall
evaluations were retained for detailed analysis.
■ Section 5 includes a detailed analysis of the remedial action alternatives that passed the
· screening process in Section 4. This analysis was performed to provide the necessary
information for EPA and the State of North Carolina to select a remedial action for
implementation. The evaluation was based on a group of technical, environmental, human
health, and institutional criteria. Cost estimates also were developed for each alternative.
■ Section 6 provides a comparison and summary of the effectiveness of each remedial action
alternative analyzed.
■ Section 7 provides references used in the preparation of this report.
Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RJCO-A44F
Sigmon's Septic Tank Site
Section l
· Revision No. 1
June 2006
Page 4 of 26
Supplementary materials (e.g., tables, figures, and appendices) referenced in this report are
included at the end of the report.
1.2 Site Background
General information pertaining to the SSTS provides the context and justification for the
remedial options identified later in this FS. This information is summarized from the OU! RI
report (Black & Veatch, 2006a) in the following sections.
1.2.1 Site Description
The SSTS is located at I 268 Eufola Road approximately 5 miles southwest of Statesville, Iredell
County, North Carolina (NCDENR [North Carolina Department of Environment and Natural
Resources], 2000a) (Figure 1-1). The SSTS is located between Eufola Road to the north and
Lauren Drive to the south. Private landowners own the properties located east and west of the
SSTS; the Pine Grove Cemetery is also located east of the SSTS (NCDENR, 2000a; USGS [U.S
Geological Survey], 1993). A landing strip is located about 0.5 miles south of the SSTS (USGS,
I 993) (Figure 1-2).
The layout and features of the SSTS are shown on Figure 1-3. The SSTS is approximately
15.35 acres in size (Moore, 1996a). According to Iredell County plat maps, the SSTS was
divided into two properties at the time of its operation; the southern parcel is 8.9 acres in size and
was listed in the name of the deceased Mr. Henry Sigmon, and the northern parcel is 6.45 acres
in size and was owned by his daughter, Ms. Mary Sigmon. Mary Sigmon and her family lived in
the onsite residence on the northern property. Several years ago, the Sigmons property was sold;
the current owner owns both parcels and resides in the onsite house formerly occupied by Ms.
Sigmon. For the purposes of this report, the property will continue to be referred to as the
"Sigmon Property."
A 1.25-acre pond (former borrow pit) is located south of the Sigmon house (Black & Veatch,
2001a). An office trailer is located south-southeast of the pond and an open-walled, roofed
storage shed is located southeast of the office. Access to the interior of the property (i.e., to the
office and open-walled shed) is provided by a gravel driveway that runs north-south along the
eastern site boundary. At the time of the initial Black & Veatch site visit (September 26, 200 I)
there were empty rusted drums, buckets, old tires, old car seats, and other debris within and near
the storage shed; these have been removed since that time. According to Mary Sigmon, these
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Final Feasibility Study Report· Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section I
Revision No. I
June 2006
Page 5 of26
materials are all from her father's operations. The drums formerly contained car wash fluids
and/or liquid waste from International Paper (Black & Veatch, 200 I a).
Approximately I 00 feet south of the shed next to the gravel access road are six above-ground
storage tanks containing liquid wastes: two rectangular concrete basins (approximately 1,000
gallons each); two cylindrical rusted tanks (approximately 10,000 gallons each); and two
cylindrical rusted tanks (approximately 12,000 gallons each). According to Mary Sigmon, the
waste contained in the above-ground storage tanks predates Sigmon Environmental operations
and the source of the waste is unknown (Black & Veatch, 2001a).
A waste pile and former lagoons are located in the southern portion of the SSTS. Two lightly
vegetated, open pits approximately 2 to 3 feet in depth are located near the southeastern comer of
the SSTS. The two pits are approximately 30 feet by IO feet and 15 feet by 8 feet in size. The
SSTS is fenced with a 4-foot barbed wire fence, and warning signs are posted on the fence and
trees. There are breaks in the fence on the eastern and southern sides of the site (Black &
Veatch, 2001a).
1.2.2 Operational History
Sigmon Septic Tank Service, a wholly owned subsidiary of AAA Enterprises, was owned and
operated by the Sigmon family since 1948. In 1970, Henry Sigmon purchased the property at
1268 Eufola Road and moved operations to this location (Moore, I 996b ). The business pumped
septic tank wastes and heavy sludges from residential, commercial, and industrial customers;
installed and repaired septic tanks; and provided a variety of industrial waste removal services.
In 1980, a nephew of Henry Sigmon, Mr. Frank Sigmon, stated to North Carolina Department of
Human Services that the septic service had pumped from Barnhardt, Clark Equipment, and
Union Glass (Grayson, 1980). In 1996, Henry Sigmon mentioned to NCDENR that some of the
septic wastes came from a medical supply company, Zimmer Industries, and a metal treating
business, Ro-Mac Company, (Moore, 1996b). Other than those sources mentioned by Mary
Sigmon, no other sources of septic waste have been named in the file material.
From 1970 to 1978, the wastewaters were discharged to the City of Statesville sewer. Around
1973 or 1974, the service received permits and land applied sludges to area farmlands (Moore,
1996b). The process of land application appears to have continued until at least 1989, according
to septage management applications filed by AAA Enterprises (NCDSWM [North Carolina
Department of Solid Waste Management], I 989a; NCDSWM, 1989b; NCDSWM, 1992). The
Final Feasibility Study Report -Operable Unit 1
EPAContract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 1
Revision No. 1
June 2006
Page 6 of26
file material does not specify on which properties the sludges were applied and whether the
farmlands produced food crops. Around 1978 or 1979, the Sigmons dug several lagoons at the
SSTS and began placing septic wastes into these lagoons (Moore, 1996b; Readling, 1990).
Henry Sigmon stated that he had received verbal permission from the Iredell County Health
Department and the Mooresville Regional Office of NCDENR to construct and use the lagoons
for septage disposal. No permits were issued for the lagoons (Moore, 1996b; Readling, 1990). It
is unknown if the lagoons ever discharged overland to the surface water pathway. AAA
Enterprises and Sigmon Septic Tank Service ceased doing business for financial reasons on
September 28, 1995 (Homesley, 1996). Shortly thereafter, Mary Sigmon purchased two trucks
from Sigmon Septic Tank Service and started Sigmon Environmental, the current operator of
septic waste services at the site (Moore, 1996b ). Sigmon Environmental has been permitted to
discharge to the Irwin Creek Wastewater Treatment Plant and the McAlpine Creek Wastewater
Treatment Plant since late 1995 (NCDSWM, 1995; NCDSWM, 1997a; NCDSWM, 1997b).
The number and size of the unlined lagoons which originally existed at the site is unclear after a
thorough review of the file material. Eight to ten unlined lagoons were utilized to hold septic
wastes. Some references indicate the lagoons were uniform in size while others depict lagoons
differing widely in size (Connell, 1995; DeRosa, 1996; Grayson, 1980; Martin, 1992; Moore,
1996b; Readling, 1990; Sigmon, 1980, Sigmon, 1995). At times, some of the lagoons were
connected with piping (referred to as a septic T) to drain water from other lagoons and facilitate
the dewatering of the sludges (Readling, 1990). · As of September 1990, eight unlined lagoons
were active; six were used for septic waste and the remaining two for dewatering (Readling,
1990). According to the son, Mr. Barry Sigmon, no septage was added. to the lagoons after the
spring of 1992 (Martin, 1992).
1.2.3 Regulatory History and Previous Investigations
The site was first investigated in June 1980 when the North Carolina Department of Human
Services inspected the site for septage disposal problems (Grayson, 1980). Nine temporary
monitoring wells were installed in the vicinity of the lagoons in September I 980 by the North
Carolina Department of Natural and Economic Resources. The samples were analyzed for
alkalinity, bicarbonate, carbonate, chloride, dissolved solids, hardness, and pH (North Carolina
Division of Environmental Management [NCDEM], 1980).
In November 1980, Sigmon Septic Tank Service submitted an interim status hazardous waste
permit application (EPA Part A) indicating that the site was used for disposal of hazardous
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Final Feasibility Study Report -Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigrnon's Septic Tank Site
Section I
Revision No. 1
June 2006
Page 7 of26
waste. The site was assigned EPA identification number NCO 062 555 792. Over the
subsequent 17 months, Mary Sigmon rescinded their permit application as a generator and
requested that the facility be reclassified as a transporter of hazardous wastes (Sigmon, 1980;
Sigmon, 1981; Sigmon, 1982; Zeller, 1981 ).
In either 1985 or 1986, two of the lagoons were apparently covered and closed out (NCDENR,
1998). In 1987, North Carolina Department of Natural Resources and Community Development
(NCDNRCD) installed and sampled four additional temporary monitoring wells (MW! through
MW4) along the western edge of the lagoons and south of the storage shed (NCDNRCD, 1987).
Analytical results indicated elevated levels of nitrates, barium, chromium, copper, iron, mercury,
manganese, and lead above EPA maximum contaminant levels (MCL) or the Title 15A
Subchapter 2L Classification and Water Quality Standards Applicable to the Groundwaters of
North Carolina. A sample of wastewater from the lagoons was also collected at this time and
contained elevated levels of arsenic, aluminum, copper, iron, mercury, magnesium, manganese,
lead, and zinc (NCDENR, 1998; NCDENR, 2000a).
Since 1989, Sigmon's Septic Tank Service has submitted applications and received permits from
the North Carolina Septage Management Program to operate a Septage Management Firm and a
Septage Disposal Site. The permit states that pumpings may only be discharged at specified
wastewater treatment plants (NCDENR, 1998).
In June 1990, the NCDEM analyzed groundwater samples from monitoring wells MW3 and
MW4 and detected elevated levels of iron, lead, manganese, and mercury above North Carolina
groundwater standards (Readling, 1990). On August 9, I 990, NCDEM notified Sigmon's Tank
Septic Service of a notice of violation regarding the groundwater contaminant levels (DeRoller,
1991 ). Sigmon's was required to submit a site assessment report and to install two monitoring
wells to replace wells MW! and MW2 which had been damaged (NCDENR, 1998).
In September 1990, the NCDEM referred the site to the North Carolina Hazardous Waste
Section, which then conducted a site investigation. It was observed that two of the lagoons had
been closed out and that two others contained the water run-off from the remaining six lagoons.
That water was used for irrigation purposes (Readling, 1990).
In March 1991, the Division of Solid Waste Management issued a notice of violation for
elevated contaminant levels in groundwater collected from onsite monitoring wells. In
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conjunction with this notice, the Division required the liquid waste and soil in each of the
lagoons to be characterized (DeRoller, 1991). Also, NCDEM began collecting groundwater
samples from nearby private wells in 1991. Detected concentrations of metals and organic
contaminants (some of those detections being elevated relative to screening values) have been
found in several samples from those wells (NCDENR, 2000a).
On August 31, and September l, 1992, NCDEM and the North Carolina Hazardous Waste
Section conducted a site investigation and sampling trip to determine whether the wastes in the
lagoons were hazardous. Water samples were collected from the eight remaining lagoons and
sludge samples were collected from five of the eight lagoons. Analytical results indicated
detectable or elevated concentrations of seven metals and 13 volatile organic compounds (VOC)
in the aqueous samples and four metals and 18 VOCs in the sludge samples. All concentrations
were below Resource Conservation and Recovery Act (RCRA) Toxicity Characteristic Leaching
Procedure (TCLP) levels; therefore, the site was transferred to the North Carolina Solid Waste
Section for continued evaluation (NCDENR, 1998).
On May 5, 1993, NCDEM analyzed groundwater samples from two monitoring wells and found
elevated levels of mercury, lead, 2-chlorotoluene, benzene, 1,3,5-trimethylbenzene, n-
butylbenzene, and naphthalene above the North Carolina groundwater standards. The Sigmons
were issued another notice of violation and were ordered to supply an alternate source of
drinking water for two residences located approximately 400 feet southwest of the lagoons
(Moore, 1996a, NCDENR, 2000a).
In September 1993, the Sigmon Septic Tank Service hired Shield Environmental Associates,
Inc., to sample and characterize the sludges in the eight unlined lagoons to comply with a closure
request by NCDENR Department of Environmental Management (Burrows, 1993). The results
indicated elevated levels of total petroleum hydrocarbons, metals, and several organic
compounds (Burrows, 1993; NCDENR, 2000a). Seven of the eight lagoons were closed by
April 1995 and the final lagoon, used to store surface water runoff during the closure process,
was closed in May 1995 (Sigmon, 1995). Reportedly, the lagoon sludges were excavated to a
depth of IO feet, mixed with sawdust, and stockpiled in one of the lagoons (Connell, 1995).
However, a neighbor who assisted in the closure, Mr. Danny Lamberth, claims that sawdust was
not added to the sludge (Black & Veatch, 200 I b ). The lagoons were backfilled with soil
excavated from the northern portion of the site. In late 1996, NCDENR visually estimated the
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section I
Revision No. I
June 2006
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quantity of sludge in the waste pile as 2,000 to 2,700 tons and the areal dimensions of the former
lagoon area as approximately 215 feet by 250 feet, or 1.21 acres (Moore, 1996b ).
In December I 995, the site was referred to the North Carolina Super fund Section by NC DEM
regarding a possible emergency removal action determination for the waste pile (Connell, 1995).
Land application of the sludge was considered but denied due to lack of sufficient acreage to
apply the sludge (NCDENR, 1998).
In December 1996, the site was added to the Comprehensive Environmental Response,
Compensation and Liability Information System database for further investigation (DeRosa,
1996). In January 1997, the North Carolina Superfund Section referred the site to the EPA
Region 4 Emergency Response and Removal Branch for a removal evaluation. In April 1997,
EPA responded that the site did not meet the criteria for an emergency removal action (Lair,
1997).
In 1998, the North Carolina Superfund Section conducted a combined Preliminary Assessment
(PA)/Site Inspection (SI) for the site. The PA/SI included the collection of nine groundwater
samples, 15 soil samples (including one duplicate), eight surface water samples (including one
duplicate), and nine sediment samples (including one duplicate). The samples were analyzed for
inorganics, volatile organics, extractable organics, and polychlorinated biphenyls (PCB). The
PA/SI confirmed the presence of groundwater contamination south and east of the site;
constituents detected in the wells included barium, chromium, lead, manganese, mercury,
chlorobenzene, 1,4-dichlorobenzene, and 1,2-dichlorobenzene. The investigation also confirmed
the presence of organic and inorganic contaminants in the soils associated with the lagoons and
waste pile. The surface water pathway was also a concern. Samples from two of the primary
points of entry (PPE) that were documented as fisheries contained barium, chromium, lead,
manganese (Davidson Pond), and magnesium (an unnamed tributary). PCBs were not detected
above the sample quantitation limit in any of the PA/SI samples (NCDENR, 2000a).
An Expanded Site Inspection (ESI) was completed by the North Carolina Superfund Section in
March 2000 (NCDENR, 2000a). The ES! included the collection of nine groundwater samples
(including one duplicate), ten soil samples (including one duplicate), six surface water samples,
and six sediment samples (Black & Veatch, 2006a). The samples were analyzed for inorganics,
volatile organics, and extractable organics. One groundwater sample was collected from an
onsite monitoring well. The remaining groundwater samples (including one duplicate) were
Final Feasibility Study Report· Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section I
Revision No, I
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collected from private wells, including one private well that served as a background well. Three
of the soil samples (and one duplicate) were collected from tlie lagoons at depths of 1 to 3 feet
below land surface (bls) or 1 to 4 feet bls. Two soil samples were collected from the waste pile
at a depth of approximately 1 foot into the pile. Two soil samples were collected as background
surface and subsurface soil samples. The remaining two soil samples were collected from the
drainage ditch on both sides of the culvert leading to the Davidson pond to determine attribution
of contamination found in the pond. Two surface water and sedjment samples were collected
from the Davidson pond, one from the PPE. into the pond and one from just upgradient of the
discharge culvert from the pond to the downgradient surface water pathway. One surface water
and sediment sample was collected at the PPE into the perennial stream located southwest of the
site. Two surface water and sediment samples were collected upstream of that PPE as attribution
samples. One surface water and sediment sample was collected from West's pond to serve as a
background sample.
Several constituents were detected in groundwater samples at concentrations either two times
greater than background levels or exceeding sample quantitation limits (SQL), including:
aluminum (8800 micrograms per liter [µg/L]), arsenic (4.2J µg/L), barium· (83 to 620 µg/L),
chromium (86 µg/L), cobalt (1.2 to 39 µg/L), iron (11,000 µg/L), manganese (15 to 27000 µg/L),
mercury (1.IJ to 6.61 µg/L), nickel (2.3 to 73 µg/L), 1,1-dicholoroethane (3 µg/L), 1,2-
dichlorobenzene (8 µg/L), l,3-dichlorobenzene (I µg/L), 1,4-dichlorobenzene (2 to 11 µg/L),
acetone (SJ to 29J µg/L), benzene (2 µg/L), chlorobenzene (72 µg/L), chloroethane (I µg/L), cis-
1,2-dichloroethene (3 µg/L), and total xylenes (2 µg/L). Analytical results are summarized in
Table 2-2 of the OUl RI report (Black & Veatch, 2006a).
The soil samples collected from the waste pile were compared to the surface soil background
sample; the soil samples from the lagoon were compared to the subsurface soil background
sample. The following constituents were detected in the waste pile samples at concentrations
either two times greater than the surface soil background concentration or exceeding the SQLs:
aluminum (31000 milligrams per kilogram [mg/kg)], antimony (42J mg/kg), arsenic (3.2 to 3.8
mg/kg), barium (230 to 310 mg/kg), cadmium (3.91 to 4.61 mg/kg), chromium (60 to 75 mg/kg),
copper (200J to 380J mg/kg), iron (17000 to 23000 mg/kg), lead (l 80J mg/kg), manganese (180
to 290 mg/kg), mercury (0.26 to 0.56 mg/kg), nickel (61 to 74 mg/kg), silver (3.5 mg/kg),
vanadium (41 to 49.mg/kg), zinc (870 to 880 mg/kg), 3-and/or 4-methylphenol (72001 µg/kg),
1, 1-biphenyl (17001 µg/kg), 4-chloroaniline (3400J to 14001 µg/kg), 1,2-dichlorobenzene (250
µg/kg), 1,3-dichlorobenzene (19 µg/kg), 1,4-dichlorobenzene (24 to 120 µg/kg), 2-
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section I
Revision No. I
June 2006
Page 11 of26
methylnaphthalene (19001 to 36001 µg/kg), acetone (21 µg/kg), benzyl butyl phthalate (220000
µg/kg), bis(2-ethylhexyl)phthalate (38000 to 240000 µg/kg), chlorobenzene (l lJ µg/kg), ethyl
benzene ( 41 µg/kg), methyl butyl ketone (270 µg/kg), methylcyclohexane ( 40 µg/kg),
naphthalene (25001 to 37001 µg/kg), phenanthrene (1800J µg/kg), toluene (63 µg/kg), and total
xylenes (200 µg/kg). Analytical results are summarized in Table 2-3 of the OU! RI report
(Black & Veatch, 2006a).
The following constituents were detected at elevated concentrations in the lagoon soil samples
when compared to the background subsurface soil sample: antimony (251 to 291 mg/kg), barium
(140 to 1400 mg/kg), cadmium (0.571 to 3.8J mg/kg), chromium (40 to 140 mg/kg), copper (641
to 3401 mg/kg), lead (841 to 2501 mg/kg), manganese (l 60 to 240 mg/kg), mercury (0.51 to 0.8
mg/kg), nickel (20 to 350 mg/kg), selenium (1.6J to 2.51 mg/kg), silver (3.2 mg/kg), zinc (310 to
1400 mg/kg), 3-and/or 4-methylphenol (23000 to 48000 µg/kg), 1,1-biphenyl (21001 to 35001
µg/kg), 4-chloroaniline (94001 to 140001 µg/kg), 1,3-dichlorobenzene (76 to 170 µg/kg), 1,4-
dichlorobenzene (44 to 290 µg/kg), 2-methylnaphthalene (22001 to 43001 µg/kg), acetone (43 to
160 µg/kg), benzenaldehyde (30001 µg/kg), benzene (14J to 18 µg/kg), bis(2-
ethylhexyl)phthalate (920J to I 00000 µg/kg), chlorobenzene (74 to 50001 µg/kg), cyclohexane
(39 µg/kg), dimethyl phthalate (47000 µg/kg), ethyl benzene (190 to 300 µg/kg),
isopropylbenzene (l lJ to 16J µg/kg), methyl ethyl ketone (34 to 76 µg/kg), methyl isobutyl
ketone (80 µg/kg), methylcyclohexane (26 to 180 µg/kg), naphthalene (20001 to 11 OOOJ µg/kg),
toluene (210 to 70001 µg/kg), and total xylenes (l SJ to 1300 µg/kg). Analytical results are
summarized in Table 2-3 of the OU! RI report (Black & Veatch, 2006a).
The soil samples collected in the drainage ditch were compared to the background surface soil·
sample. The following constituents were detected at elevated concentrations when compared to
the background surface soil sample: aluminum (30,000 mg/kg), arsenic (2.7 to 3.4 mg/kg),
barium (85 to 160 mg/kg), chromium (21 to 31 mg/kg), cobalt (7.8J mg/kg), copper (I OJ to 24 J
mg/kg), iron (19000 to 20000 mg/kg), lead (12J to 131 mg/kg), manganese (1300 to 4200
mg/kg), nickel (8.2 to 17 mg/kg), vanadium ( 45 to 46 mg/kg), zinc (36 to I 00 mg/kg),
benzenaldehyde ( 440J µg/kg), benzo(a)anthracene (830 µg/kg), benzo(a)pyrene (730 µg/kg),
benzo(b )fluoranthene (960 µg/kg), benzo(k)fluoranthene (840 µg/kg), chrysene (920 µg/kg),
dimethyl phthalate (460 µg/kg), fluoranthene (1600 µg/kg), phenanthrene (1200 µg/kg), and
pyrene (1600 µg/kg). Analytical results are summarized in Table 2-3 of the OU! RI report
(Black & Veatch, 2006a).
Final Feasibility Study Report• Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 1
Revision No. 1
June 2006
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Surface water sample SST-023-SW was considered a background sample during the ES!;
however, it was collected from a surface water pathway that has the potential for being impacted
by the site. The following constituents were detected in surface water samples at elevated
concentrations when compared to background sample SST-021-SW: aluminum (1900 µg/L),
arsenic (3.6J to 18J µg/L), barium (14 to 210 µg/L), cadmium (I to 1.2 µg/L), cobalt (4.8 to 14
µg/L), iron (740 to 7000 µg/L), lead (1.3 to 4.1 µg/L), manganese (35 to 1300 µg/L), nickel (4.3
to 11 µg/L), and zinc (85 to 220 µg/L). The highest concentrations of these constituents were
typically found in the samples collected from the Davidson pond. Analytical results are
summarized in Table 2-4 of the OUl RI report (Black & Veatch, 2006a).
Sediment sample SST-023~SD was considered a background sample during the ES!; however, it
was collected from a surface water pathway that could potentially be impacted by the site. The
following constituents were detected in sediment samples at elevated concentrations when
compared to background sample SST-021-SD: arsenic (8 mg/kg), barium (210 mg/kg),
chromium (46 mg/kg), copper (37J mg/kg), iron (3200 to 37000 mg/kg), manganese (280 to 380
mg/kg), nickel (21 mg/kg), and zinc (150 mg/kg). Analytical results are summarized in Table 2-
5 of the OU! RI report (Black & Veatch, 2006a).
The two soil samples collected from the drainage ditch upgradient of the Davidson pond have
also been included on Table 2-4 of the OU! RI report (Black & Veatch, 2006a). Although not
detected above the SQLs of the background sediment sample, numerous polynuclear aromatic
hydrocarbons (P AH) were detected in the Davidson pond, Many of these constituents were also
detected in the soil sample SST-018-SL collected in the drainage ditch between the road and the
pond, indicating that contamination in the pond may be attributable to a source other than the
site.
Black & Veatch conducted a site visit in September 200 I. The site was evaluated by Black &
Veatch ecological and human health risk assessors, the Black & Veatch project manager, and
EPA personnel to determine the appropriate RI sampling locations. A statistically based protocol
for selecting an appropriate soil grid size for the field investigation was applied by Black &
Veatch and EPA (Black & Veatch, 2002b) using the Visual Sample Plan (Hassig et al., 2005).
EPA recommended a geophysical investigation for the SSTS in order to further focus the soil
investigation.
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RJCO-A44F
Sigmon's Septic Tank Site
Section I
Revision No. I
June 2006
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In May 2002 Black & Veatch personnel assisted EPA Sciences and Ecosystem Support Division
(SESD) in a geophysical investigation at the SSTS. The objective was to obtain information on
the location of the former lagoons and pits which would guide future soils sampling and support
the Rl/FS for the SSTS. Data was collected using the electromagnetic induction meter (EM31-
MK2) and the magnetometer (G-856). The results of that investigation, documented in the
Geophysical Investigation Report for Sigmon's Septic Tank Sile, Statesville, North Carolina
(EPA, 2002a), indicated the presence of both non-ferrous and ferrous metallic, non-native
materials in the subsurface soil at the SSTS. Those results were used to guide future soil
sampling investigations. That geophysical investigation report is presented in Appendix A of the
OU! RI report (Black & Veatch, 2006a).
Black & Veatch submitted a "Final" screening-level ecological risk assessment (SLERA) to the
EPA on July l, 2002. The SLERA was based on data collected during the ES! conducted at the
SSTS. Black & Veatch collected additional data as part of the RI sampling investigation in
October 2002. The additional data was evaluated to determine its impacts on the conclusions of
the July 2002 SLERA. There were contaminants exceeding the concentrations reported in the
July I, 2002 SLERA that would have affected the outcome of the SLERA. These included
beryllium and thallium in surface soil. In addition, contaminants detected in the October 2002
RI sampling event but not analyzed for in the July I, 2002 SLERA include 4,4'-DDD and alpha-
Chlordane in sediments; PCB-I 260 in surface water; and numerous pesticides/PCBs and dioxins
in surface soil. A technical review of the SLERA performed for the site and other pertinent
information available at the time (Steiner, 2002), it was concluded that ecological risk would not
require further evaluation. Chapter 7 of the OU! RI discusses the decision regarding ecological
risk assessment at the SSTS.
In October 2004, a data evaluation report (DER) was completed by Black & Veatch in
accordance with the Final RJ/FS Work Plan for the SSTS (Black & Veatch, 2002a). The DER
evaluated the usability of data collected by the RI project team to support project conclusions
and recommendations for the SSTS RI/FS. The DER summarized and evaluated data collected
from the October 2002, March and April 2003, and May 2004 sampling events. An additional
field investigation was conducted in February 2005 to primarily address the delineation of soil
contamination at the SSTS. A DER was not written for the February 2005 soil data; however,
the OU! RI report (Black & Veatch, 2006a) reviews, evaluates, and discusses this new data set
in detail; therefore, a separate DER was not necessary. The October 2002, March and April
2003, May 2004, and February 2005 sampling investigations and data sets collected during the
Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 1
Revision No. I
June 2006
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remedial field investigations (RFI) are presented and further evaluated in the OU 1 RI report
(Black & Veatch, 2006a).
1.3 Nature and Extent of Contamination
The OU! (soil) RI for this site successfully delineated the nature and extent of contamination in
all media except for the extent of groundwater contamination. This section discusses the nature
and extent of contamination at the SSTS. This evaluation is based on a detailed discussion of
analytical results associated with environmental media samples collected during RI fieldwork
conducted between October 2002 and February 2005.
1.3.1 Source Areas
The contaminant source areas at the SSTS site consist of soil and debris associated with eight to
ten unlined lagoon pits created by the site owners in 1978 or 1979. These pits were used to hold
septic tank wastes and heavy sludges from residential, commercial, and industrial customers;
other waste-related activities include installing and repairing septic tanks and providing a variety
of industrial waste removal services.
Numerous samples of media from the suspected source area were analyzed for inotganics,
dioxins/furans, semi volatile organics, pesticides/PeBs, and volatile organics. A number of these
~alytes were detected among the various media samples; however, not all analyte detections
exceeded corresponding screening values. The analytical data obtained from these sampling
efforts suggests that the nature of contamination at the SSTS is relatively narrow in scope,
limited to primarily metals with some localized svoe and voe contamination.
Samples of media from the source area contain consistent and frequent detections and screening
value exceedences of the following metals: aluminum, arsenic, barium, calcium, chromium,
copper, iron, lead, magnesium, manganese, nickel and zinc. Samples of surface soil and
subsurfac~ soil contain frequent detections and a few screening value exceedences of a number
of SVOes ( e.g., naphthalene, various PAHs, bis-[2-ethylhexyl] phthalate, I, I '-bi phenyl) and
some pesticides (e.g., alpha-chlordane, gamma-chlordane, heptachlor epoxide, alpha-BHe, beta-
BHe, 4,4'-DDE and 4,4'-DDT). Subsurface soil contains many voes, including chlorinated
compounds ( e.g., 1,4-dichlorobenzene, total xylenes, trichloroethene, toluene, tetrachloroethene );
surface soil contains very few voe detections and no screening value exceedences (Table 4-13
of the OU! RI report [Black & Veatch, 2006a]).
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Sc:ptic Tank Site
Section I
Revision No. I
June 2006
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Subsurface soil associated with the site boundaries may be impacted by site-related
contamination through infiltration of precipitation, percolation of contaminants associated with
the downward migration of storm-water, and soil grading activities involving trenching and
digging into the subsurface.
1.3.2 Downgradient Media
Around I 973 or 1974, the owners of the site received permits to land-apply sludges to area
farmlands (Moore, I 996b ). The process of land application appears to have continued until at
least 1989, according to septage management applications filed by AAA Enterprises
(NCDSWM, 1989a; NCDSWM, 1989b; NCDSWM, 1992). The file material does not specify
on which properties the sludges were applied and whether the farmlands produced food crops.
Based on observations made during field sampling events in the 2004-2005 time period, surface
soil within the site boundaries appears to have been moved by grading activities and by
incidental transport with vehicular traffic. It is likely that attempts had been made to grade the
surface soil into piles creating berm-like features along the circumference of the presumed
sludge lagoon pit area in the southern third of the site boundary. The configuration of these
berm-like piles, and the subsequent regrowth of short vegetation and grasses on the material,
seems to successfully minimize surface soil erosion to the south and retain precipitation and
erosion to within the site boundaries. Currently the surface topography slopes east to west.
From I 970 to 1978, the wastewaters were discharged to the City of Statesville sewer. The
current operator of septic waste services at the site (Sigmon Environmental; Moore, 1996b) was
given a permit to discharge to the Irwin Creek Wastewater Treatment Plant and the McAlpine
Creek Wastewater Treatment Plant beginning in late I 995 (NCDSWM, I 995; NCDSWM,
1997a; NCDSWM, I 997b ).
It is unknown if the lagoons ever discharged overland to the surface water pathway. Surface
water features near the site consist exclusively of ephemeral drainage ditches that collect storm-
water and are the discharge points for shallow groundwater flow at the site. One unnamed
drainage feature exists to the south of the site, and another unnamed drainage feature carries
drainage from Sigmon onsite toward the west. The nearest perennial creeks or rivers are about ½
mile west and southwest of the site (i.e., Reeder Creek and the Catawba River). Uncontrolled
migration of overland storm-water flow may impact several surface water features in the area:
Davidson Pond to the south of the site, Sigmon Pond within the site boundaries, and Lambreth
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Work Assignment No. 340-RICO-A44F
Sigrnon's Septic Tank Site
and Williams Ponds to the west of the site (Figure 1-3). Further west of these, Sliwinski Pond
lies within the drainage ditch system between the site and the Catawba River, and it could
receive storm-water flow originating from the site, as well (Figure 1-2).
Samples of surface water and sediment contain consistent and frequent detections and screening
value exceedences of the following metals: aluminum, arsenic, barium, calcium, chromium,
copper, iron, lead, magnesium, manganese, nickel and zinc. Surface water and sediment contain
very few VOC detections and ·no screening value exceedences (Table 4-13 of the OU! RI report
[Black & Veatch, 2006a ]).
1.4 Contaminant Fate and Transport
The primary sources of contamination at the site are summarized in Section 1.3. I of this FS
report. Almost all contaminant inputs at the site occurred prior to 1990. The time lag between
the last contaminant input and current conditions has direct implication on the aging and
equilibration of contaminants in the environment. Volatilization is a relatively rapid process that
can occur soon after entry to the environment. Solubility also is a relatively rapid process; most
of the mass of soluble contaminant can dissolve soon after entry into the environment. For
partially or slightly soluble material, there could be ongoing dissolution over time as new
percolating storm water is introduced to the contaminant source. Adsorption mechanisms over
time may trend toward stronger bonding strength resulting in the contaminant being more
tightly-bound to the sorbent (e.g., soil particle, organic matter, mineral crystal, etc.).
Based on the nature of the contamination at the site and the physical characteristics of the site,
potential routes of contaminant migration likely include the following:
•
•
•
•
Slow migration due to strong binding of contaminants to surface and subsurface soil media .
Dissolution and migration with percolating storm water (i.e., in the vertical direction from
surface soil to subsurface soil to groundwater).
Overland transport of bound contaminants associated with water-eroded soil media (i.e.,
from surface source areas along drainage pathways to aquatic media).
Movement of bound contaminants associated with soil or water media incidentally attached
to mobile receptors such as human workers, human residents, ecological species, etc.
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section I
Revision No. I
June 2006
Page 17of26
Any metals present in the surface or subsurface soil media at the site are likely in the form of
insoluble minerals because more readily soluble metal species likely already have dissolved and
moved off site since the initial contaminant input(s). These migration routes are summarized
further in the following sections.
1.4.1 Soil-to-Groundwater Migration
Analytical data shows similar contaminants detected in surface soil, subsurface soil, and shallow
groundwater. These results suggest that contaminants have migrated downward since the initial
source inputs during periods of active site-use. Likely migration downward is based on two
mechanisms: (!) dissolution of soil-bound or soil-associated contaminants in infiltrated storm
water followed by the downward percolation of storm water flow through soil and (2) downward
migration of soil particles due to mixing and settling.
1.4.2 Soil-to-Surface Water/Sediment Migration
Topography at the site may have changed over time. Currently, topography supports retention of
storm water on the southern portion of the site or migration of storm water to the central areas of
the site boundary. In the past, eroded contaminated soil may have been carried overland in one
of two directions: (I) south toward the ephemeral drainage features located to the south of the
site (e.g., unnamed drainage tributary and Davidson Pond) and (2) north toward the central
portion of the site where Sigmon Pond is located. From this dispersion of contaminants,
additional transport can occur from cycles of suspension and deposition of contaminated
soil/sediment.
1.4.3 Groundwater-to-Surface Water Migration
Based on empirical observations of surface water features near the site, shallow groundwater
likely is connected to several of the surface impoundment ponds and drainage ditches located
within and around the site. This suggests that groundwater can emerge from the subsurface into
these surface features; thus contaminated groundwater can migrate from the subsurface to the
surface water and further downgradient along the surface water drainage pathways.
1.5 Human Health Risk Assessment
This section summarizes the Baseline Human Health Risk Assessment (HHRA) for the site,
highlighting the contaminants of concern (COCs) selected, the approaches used for estimating
exposure, the toxicological assumptions, and the total potential carcinogenic and non-
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carcinogenic risks to each receptor group. For more details, refer to the original HHRA ( see
Section 6 and Appendix M of the OU! RI report [Black & Veatch, 2006a]).
1.5. 1 Contaminants of Concern
Contaminants in source area media were identified from samples of soil and on-site groundwater.
Groundwater was included in the HHRA because(!) the nature of contamination in groundwater
was adequately determined, although the extent of contamination requires further investigation,
and (2) including it allows risk managers to address soil-to-groundwater leaching potential.
Although over I 00 chemicals (including VOCs, semi volatile organic compounds (SVOCs),
P AHs, pesticides, PCBs, dioxin and inorganics) were detected in these media, many of the
concentrations were below screening values. The maximum detected concentrations were
compared to risk-based screening levels (EPA Region 9 Preliminary Remediation Goals
[PRGs]).
Through this process, a large number of constituents were eliminated and selected as chemicals
of potential concern (COPCs) for the SSTS. The Risk Assessment Guidance for Superfund
(RAGS) Part D Tables 2.1 through 2.25 in Appendix M of the OU! RI report documents the
elimination of VOCs, SVOCs, pesticide, and PCBs in onsite surface soil; SVOCs, PAHs,
pesticides, and PCBs in onsite subsurface soil; VOCs, SVOCs, pesticides, PCBs, and PAHs in
offiste surface soil; VOCs, SVOCs, PAHs, pesticides, PCBs, and dioxin in offsite subsurface
soil; VOCs and PCBs in surface water; and SVOCs, pesticides, and PCBs in groundwater (Black
& Veatch, 2006a).
Not every COPC selected and carried through the risk assessment was retained as a COC. Those
constituents retained as COCs were chemicals that significantly contributed to a use scenario for
a receptor that exceeded a I E-04 total carcinogenic risk or exceeded a hazard index (HI) of I.
Individual chemicals contributing to these scenarios, that were greater than or equal to I E-06 for
carcinogens or yielded a hazard quotient (HQ) greater than or equal to 0.1 for noncarcinogens
were considered COCs.
1.5.2 Exposure Scenarios and Receptors
The exposure assessment consisted of characterizing the local climate, geology, soils,
groundwater, surface water conditions, and population demographics, as well as identifying
exposure pathways and quantifying exposure intakes for each receptor group at the site. Local
population statistics and land/water uses also were presented. A fate and transport analysis of the
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Final Feasibility Study Report -Operable Unit I
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COCs in conjunction with the source area characteristics identified the potential constituent
migration and exposure pathways at the site. An exposure pathway screening was conducted to
identify those pathways warranting inclusion in the detailed quantitative analysis. Exposure
pathways identified by the risk assessments as most applicable to the SSTS site are presented in
the OU! RI report (Black and Veatch, 2006a). Exposure was quantified based on an analysis of
the COC exposure point concentrations for each media in each exposure unit. Intake was
estimated for receptors for each media in each exposure unit.
1.5.3 Toxicity Assessment
The toxicity assessment presented the available human health toxicological health effect criteria
for each COC and for each exposure route identified for the site.
For carcinogenic effects, the available oral and inhalation cancer slope factors and unit risk
factors were identified and presented for each constituent classified as a carcinogen by EPA. In
addition, dermal cancer slope factors were calculated by dividing the oral cancer slope factor by
an oral-to-dermal adjustment factor.
For chronic noncarcinogenic effects, the available oral and inhalation reference doses and
reference concentrations were identified and presented for each constituent. In addition, dermal
reference doses were calculated by multiplying the oral reference dose by an oral-to-dermal
adjustment factor.
For acute noncarcinogenic effects, the available acute inhalation health effects criteria were
reviewed for each COC selected for the surface and subsurface soil exposure pathways. Since
acute inhalation reference concentrations were not available, to provide a conservative evaluation
and in consultation with the EPA Region 4 toxicologist, the lowest available acute toxicity value
for each constituent was selected as the toxicity value for purposes of evaluating the potential for
acute health effects associated with inhalation of dusts at the SSTS site. The toxicity values used
for COC in each media in each exposure unit as presented in RAGS Part D Tables 5 and 6
(Tables 5. l through 5.3 and Tables 6. l through 6.2) in Appendix M of the OU l RI report (Black
& Veatch, 2006a).
1.5.4 Risk Characterization
Potential cancer risks and noncancer hazards associated with exposures at each of the
investigated areas at the SSTS site are summarized below. Included in this summary are
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contaminants that appear to present an unacceptable risk but which actually are present at
concentrations within or near concentration ranges found in background samples. Although
included in this summary, such contaminants are not to be considered _in the development of
remedial alternatives for this site. These contaminants also are discussed in detail in the original
HHRA (see Section 6.1 of the OU! RI report [Black & Veatch, 2006a)]).
A total of six chemicals were identified as COCs in onsite and offsite soil including aluminum,
chromium, iron, thallium, vanadium and trichloroethene (TCE). However, based on the limited
toxicity data available additional discussion is warranted for the constituent TCE.
TCE was not detected in the onsite surface soil; TCE was only detected in one onsite subsurface
soil sample at a concentration exceeding the PRO (it was detected at a concentration of 38,000
mg/kg in onsite subsurface in sample SS-SB2-06). Also, as discussed in Section 6.2.4.2.1 of the
OU! RI report (Black & Veatch, 2006a), the reference dose (Rills) for this compound is
considered Tier 3 toxicity criteria. The EPA Region 9 PRO table value was used because other
toxicity criteria is lacking. However, the values are outdated, and therefore, should not be used
as the basis for any remediation decisions. Therefore, since the hazard quotient for TCE is based
on Tier 3 toxicity criteria and subsurface soil is not currently available for direct contact, TCE is
not likely to pose a significant threat to receptors at the site and remediai goal options (ROOs)
were not calculated for TCE.
1.5.5 Remedial Goal Options
This section contains the site-specific ROOs for the chemicals and media of concern at the SSTS.
In accordance with Region 4 guidance (EPA, 2000a), ROOs are included in the Baseline HHRA
to provide the Remedial Project Manager with a range of risk-based media cleanup levels options
and ARARs as a basis for developing the selected remediation goals in the FS and Proposed
Plan.
ROOs were developed for COCs in each land use scenario evaluated in the HHRA for this site.
COCs are chemicals that significantly contribute to a use scenario for a receptor that exceeds a
1 E-04 total carcinogenic risk or exceeds a HI of 1. Individual chemicals contributing to these
scenarios had ROOs developed if their contribution was greater than or equal to 1 E-06 for
carcinogens or yielded a HQ greater than or equal to 0.1 for noncarcinogens. Using the above
criteria, the appropriate chemicals, exposure units, exposure routes, and receptors for which
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Final Feasibility Study Report -Operable Unit I
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Work Assignment No. 340-RICO-A44F
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RGOs were calculated were selected from RAGS Part D Tables 9.1 through 9.17 (Appendix M
of the OU I RI report (Black & Veatch, 2006a)).
RAGS Part D Tables 11. I through 11.6 (Black & Veatch, 2006a) present the media-specific
RGOs for the COCs for each exposure scenario (refer to Appendix M RAGS Part D Tables I 0.1
through 10.9 (Black & Veatch, 2006a) for the media, scenarios, exposure units, and COCs which
present unacceptable risks and hazards). The derived RGOs reflect the combined exposure
through the applicable routes for any given medium (i.e., for exposure to surface soil, incidental
ingestion inhalation, and dermal contact were combined).
The results of the HHRA indicate that the current adolescent trespasser and future outdoor
worker exposure to surface soil, surface water, and groundwater do not 'result in any
unacceptable cancer risks or hazards. The results also indicate that the current/future adult
resident's exposure to offsite surface soil, surface water, and potable wells PW-03, PW-05, and
PW-IO were below the HI of 1, the applicable threshold for hazards. Additionally, the cancer
risks for all receptors were at or below the unacceptable risk level, a cumulative excess lifetime
cancer risk of I E-04.
The hazards for the future construction worker and adult and child residents were above the
applicable thresholds (a total HI greater I). The largest contributors to the HI for the
construction worker included ingestion of iron and vanadium in surface soil; ingestion of
chromium, iron, and vanadium in subsurface soil; and ingestion of arsenic, barium, iron,
manganese, mercury, and vanadium in groundwater.
The contributors to the HI for the adult resident included ingestion of iron in surface soil and
ingestion of aluminum, arsenic, barium, iron, manganese, mercury, and vanadium in
groundwater.
The contributors to the HI for the child resident included ingeslion of aluminum, chromium, iron,
thallium, and vanadium . in surface soil and ingestion of aluminum, arsenic, barium, iron,
manganese, mercury (PW-03), vanadium, and zinc (PW-10) in groundwater. Additionally,
ingestion of mercury in potable well PW-03 and zinc in potable well PW-10.
Although aluminum was identified as a COC for both ons_ite and offsite surface soil in Section
6.2. 7 of the HHRA in the OU I RI Report (Black & Veatch, 2006a), further evaluation of both
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the historical and RI field investigation data revealed that the maximum concentrations found in
surface soil (72,000 mg/kg and 64,000 mg/kg) were less than the risk-based RGO of 76,865
mg/kg; therefore, aluminum was eliminated as a COC for surface soil.
Although chromium was identified as a COC for both surface and subsurface soils in Section
6.2.7 of the HHRA in the OU! RI Report (Black & Veatch, 2006a), further evaluation of both
the historical and RI field investigation data revealed that the maximum concentrations found in
surface soil were less than the risk-based RGO of 155 mg/kg and the maximum concentrations
found in subsurface soil were less than the risk-based RGO of 858 mg/kg. Therefore, chromium
has been eliminated as a COC for surface and subsurface soil.
Although irori was identified as a COC for both surface and subsurface soils in Section 6.2.7 of
· the HHRA in the OU! RI Report (Black & Veatch, 2006a), further evaluation of both the
historical and RI field investigation data revealed that with the exception of one location, the
maximum concentrations found in surface soil were less than the risk-based RGO of 22,730
mg/kg and the maximum concentrations found in subsurface soil were less than the risk-based
RGO of 91,729 mg/kg; therefore, iron was eliminated as a COC for both surface and subsurface
soils.
Based on the HHRA, thallium was originally identified as a COC for surface soil; however,
maximum concentrations found in both surface soil and subsurface soil were less than the risk-
based RGO of 6 mg/kg. Therefore, thallium was· eliminated as a COC for surface soil and
subsurface soil.
Based on the HHRA, vanadium was identified as a COC for surface soil. Concentrations of
vanadium were found in both onsite and off-site surface soils above the risk-based RGO of 73
mg/kg; therefore, vanadium and has been included as a COC for surface soil.
1.5.6 Leachability Criteria for Groundwater COCs present in Soils
The general approach for determining screening criteria to evaluate the potential for soil-to-
groundwater leaching was discussed in Sectiori 5. This section presents the soil screening
standards based on soil-to-groundwater leaching for the groundwater COCs identified in Section
6.2.7 in the OU! RI report (Black & Veatch, 2006a). The criteria evaluated and selected are
presented in Table 6-1 and discussed. below:
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Work Assignment No. 340-R!CO-A44F
Sigmon's Septic Tank Site
• EPA Region 9 PRGs -

A

site-specific dilution attenuation factor (OAF= 3) was determined
in the OU! RI (Black & Veatch, 2006a). The screening criteria based on the site-specific
OAF was determined via linear interpolation between the criteria presented for OAF = I
and OAF= 20.
•
•
Groundwater Section Guidelines for the Investigation and Remediation of Soil and
Groundwater (NCOENR, 2000a).
Leachability criteria provided by Nile Testerman (NCOENR Project Manager) or
calculated by Black & Veatch (Black & Veatch, 2004).
Where criteria from two or more of these sources was available, the lowest concentration was
selected. Comparison of these standards to the data presented in Section 4 resulted in the
following general conclusions:
•
•
•
Aluminum: The leachability screening concentration of72,0I0 mg/kg was not exceeded by
any of the surface soil samples, and in only one of the subsurface soil samples. Therefore,
aluminum has been eliminated as a COC for surface and subsurface soil.
Arsenic: For protection of groundwater and as stated in Section 6.2.8 of the HHRA in the
OU! RI )3.eport (Black & Veatch, 2006a), arsenic was found in very few surface and
subsurface soil samples exceeding the EPA leachability standard for protection of
' groundwater of 4.0 mg/kg calculated using default parameters; however, arsenic was not
found in any of the groundwater samples at levels exceeding the MCL of IO ug/L except
for one groundwater sample collected in October of 2002 from SS-MW-11 C at a
concentration of 26 ug/L. Therefore, arsenic has been eliminated as a COC for surface and
subsurface soil.
Barium: Barium was not detected in groundwater above the MCL of 2,000 ug/L even
though as stated in Section 6.2.8 of the l:IHRA in the OU! RI Report (Black & Veatch,
2006a), barium was found in eight surface soil locations and several deep boring locations
in the lagoon exceeding the NC leachability standard for protection of groundwater of
241.8 mg/kg which was calculated using default parameters. Therefore, barium has been
eliminated as a COC for surface and subsurface soil.
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• Lead: Based on the HHRA, lead was not identified as a COC for surface soil, subsurface
soil, or groundwater. Although lead was detected in many of the soil samples across the
site, it only exceeded the groundwater protection value of270 mg/kg at SB-06 at a depth of
5-7 feet (Figures 1-4 and 1-5). Furthermore, low concentrations of lead generally less than
5 ug/L were found in the majority of wells; however, the only exceedences of the MCL (15
ug/L) were found at potable wells PW-09 and PW-10 and monitoring well MW-14. Both
wells PW-09 and PW-10 are located upgradient of the site. At well PW-09, lead was
detected at 50 ug/L in 2002, 14A ug/L in 2003, 20J ug/L in 2004 and 4.3J ug/L in 2005. At
well PW-I 0, lead was detected at a concentration of l 40J ug/L in 2004 and I lJ ug/L in
2005. Lead was detected at a concentration of 16 ug/L in well MW-14, but this may be
falsely high due to the high turbidity (380 NTUs) of the sample. Based on subsequent risk
management discussions with EPA and the State of North Carolina, the determination was
made not to include lead as a COC for surface and subsurface soil.
• Manganese: Although manganese was identified as a COC for groundwater in Section
6.2. 7 of the HHRA in the OU! RI Report (Black & Veatch, 2006a), further evaluation of
both the historical and RI field investigation data revealed that manganese exceeded the
EPA's health advisory value of 300 ug/L in three of the site monitoring wells MW-I IC,
MW-13B, and MW-14 and five of the push point/temporary wells (PP-5, PP-7, PP-8, TW-
3, and TW-9) (Figure 1-6). The concentration of manganese found in the three monitoring
wells ranged from 5,200 to 19,000 ug/L. The wells are all located in the_ southwestern area
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of the site. These results indicate the potential of a manganese plume originating in the 1 southern portion of the site. Groundwater in this area generally flows to the south and
southwest. The septic pits were located in the southern portion of the site. Using the EPA
health advisory value of 300 ug/L, a leachability standard for protection of groundwater of I
391 mg/kg was calculated. The subsurface soil samples that exceeded this standard were
found in the southern portion of the site at concentrations ranging from 430 mg/kg to 1,300
mg/kg (Figure 1-7). The orientation and concentration of these subsurface soil samples
suggest the possibility that the high level of manganese observed in the wells may be site
related. It is possible that the oxidatioiyreduction of chlorinated solvents located in the
center of the southern portion of the site resulted in the mobilization of manganese in this
area. Upon further discussions with EPA and the State of North Carolina, it was determined
that the concentration of manganese in the groundwater will be monitored over time.
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• Mercury: Based on the HHRA, mercury was not identified as a COC for either surface and
subsurface soil, but was preliminarily identified as a groundwater COC based on a NC leachability standard of 0.015 mg/kg. Although mercury was detected in many of the subsurface soil samples in the southern half of the property above this groundwater
protection number of 0.015 mg/kg with a maximum concentration of 1.6 mg/kg at SB-06 at a depth of 5-7 ft, mercury was only detected in two wells, potable well PW-03 and
monitoring well MW-14 (Figure 1-8). The federal MCL (2 ug/L) as well as the North Carolina MCL (I. I ug/L) were exceeded only at PW-03 (2.IA ug/L) during the 2002
sampling event but the mercury concentration at this well decreased to 0.98 ug/L in 2004
and 0.2 ug/L in 2005. Mercury was also found in well MW-14 at a concentration of 441 ug/L in 2004 but this result may be falsely high due to the high turbidity (380 NTUs) of the sample. Based on subsequent risk management discussions with EPA and the State of
North Carolina, the determination was made to eliminate mercury as a COC for surface and subsurface soil.
• Vanadium: The leachability screening concentration of900 mg/kg was not exceeded in any of the surface or subsurface samples.
• Zinc: Based on the HHRA, zinc was originally identified as a COC for groundwater based
on an EPA protection of groundwater leachability standard of 1817 .8 mg/kg; maximum
concentrations found in surface soil were below this standard and just barely above this standard in a few locations in subsurface soil. Based on the fact that zinc was not found above the MCL of 5,000 ug/L in any of the wells, it was eliminated as a COC for surface
soil, subsurface soil, and groundwater.
Based on further evaluation of both the historical and RI field investigation data and risk management discussions with EPA and the State of North Carolina, the only.COC for the SSTS is as follows:
• Surface Soil (Onsite/Offsite): Vanadium
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1.6 Ecological Risk Assessment
Section 1
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EPA evaluated the potential for ecological risks at the SSTS. Ecological risk assessment
addressed the objectives set forth by the National Contingency Plan, 40 Code of Federal
Regulations 300, under CERCLA for protection of the environment from current and potential
threats posed by an uncontrolled hazardous substance release. After evaluation of the SLERA
(Steiner, 2002), EPA determined that there was no ecological risk associated with the SSTS.
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site:
2.0 Identification and Screening of Technologies
2.1 Basis for Remedial Action
Section 2
Revision No. I
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Justification for RAO development and subsequent remedial action at the SSTS is based on the
evaluation of four factors (listed below):
• The nature and current extent of contamination at the site.
•
•
The potential for current contamination to migrate and continue to be a potential hazard .
The existence of risk-based COCs as determined by the Baseline Risk Assessment
presented in Section 6.0 of the OU! RI report (Black & Veatch, 2006a).
• Any existing ARARs for the SSTS.
The first criterion (nature and extent of contamination) is evaluated in Section 4 of the OU! RI
report (Black & Veatch, 2006a) and is summarized in Section 1.3 of this FS report. That
evaluation identified areas associated with the Former Lagoon Pit area, smaller areas in the
central and northern portions of the SSTS represent areas onsite, and ponds located offsite, as
areas of contamination to be addressed by the SSTS risk management team. The RAOs for the
SSTS were designed to reduce or eliminate contaminated media at these locations.
The second criterion (fate and transport) is evaluated in Section 5 of the OU! RI report (Black &
Veatch, 2006a) and is summarized in Section 1 .4 of this FS report. Soil-associated contaminants
appear to have migrated vertically from their original source location by leaching from surface
and shallow subsurface soil to deeper layers of subsurface soil and possibly into shallow
groundwater under the SSTS. Lateral migration may have occurred through overland surface
runoff flow from source areas to local surface drainage pathways ( e.g., ponds and drainage
ditches). The RAOs for the SSTS were designed to eliminate source material (to prevent
additional migration of contamination) and currently contaminated media (to reduce the potential
for receptors' exposure to contamination).
The third criterion (risk) is evaluated in Section 6 (human health) and 7 (ecological) of the OU!
RI report (Black & Veatch, 2006a) and is summarized in Section 1.5 and 1.6, respectively, of
this FS report. Potential risk to human receptors ( e.g., child, etc.) exists with exposure to surface
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soil-associated COCs (onsite: vanadium; offsite: vanadium) and subsurface soil-associated COCs
( onsite: vanadium). The unsecured soil stockpile located in the southern half of the site contains
various organic and inorganic contaminants (NCDENR, 2000). It is also assumed that
contamination from the stockpile has leached downwards to a depth of 5-7 feet below the ground
surface in the area of the stockpile.
The fourth criteria for the SSTS (i.e., ARARs criterion) is evaluated in the following subsections
in preparation for RAO development.
2.2 Applicable or Relevant and Appropriate Requirements
Remedial actions must comply with ARARs of federal laws and more stringent, promulgated
state laws. Applicable requirements include federal or state cleanup standards, standards of
control, and other substantive requirements, criteria, or limitations that specifically address a
hazardous substance, pollutant, contaminant, remedial action, location, or other circumstance at
the site. Relevant and appropriate requirements include federal and state cleanup standards,
standards of control, and other substantive environmental protection requirements, criteria, or
limitations that, while not applicable, address problems or situations sufficiently similar to those
at the site that their use is well suited (EPA, 1987). EPA's Interim Guidance on Compliance with
Applicable or Relevant and Appropriate Requirements (EPA, 1987) and CERCLA Compliance
with Other Laws Manual Part II (EPA, 1989) establish how requirements of federal and state
laws are generally identified and applied to remedial actions at CERCLA sites.
ARARs are determined by applying a two-tiered test to determine first whether the requirement
is applicable or second to determine whether the requirement is relevant and appropriate.
Applicable requirements means those cleanup standards, standards of control, and other
substantive environmental protection requirements, 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 (EPA, 1987). · Relevant and
appropriate requirements means those cleanup standards, standards of control, and other
substantive environmental protection requirements, criteria, or limitations promulgated under
Federal or State law that, while not "applicable" to a hazardous substance, pollutant,
contaminant, remedial action, location, or other circumstance at a CERCLA site, address
problems or situations sufficiently similar to those encountered at the CERCLA site that their use
is well suited to the particular site (EPA, 1987).
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Final Feasibility Study Report -Operable Unit I
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Section 2
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In addition, the guidance documents also identify nonpromulgated advisories or guidance
documents issued by federal or state governments as "to-be-considered" materials (TBCs) for the
site. TBCs are not considered legally enforceable and, therefore, are not considered to be
applicable for the site but are evaluated along with ARARs to set protective cleanup level targets.
TBCs should be used in the absence of ARARs when ARARs are not sufficiently protective to
develop cleanup goals or when multiple contaminants may be posing a cumulative risk (EPA,
I 987).
2.2.1 Chemical Specific Requirements
Chemical-specific ARARs establish health or risk-based concentration limits for various media,
and may set cleanup levels for specific chemicals or discharge limits. This section outlines many
(but perhaps not all) of the federal and state chemical-specific ARARs applicable to the SSTS
site. All of the ARARs provide some specific guidance on "acceptable" or "permissible"
concentrations of contaminants in water. Identified chemical-specific ARARs for various
contaminants at the SSTS are summarized in Table 2-1.
2.2.2 Location Specific Requirements
Action-specific ARARs establish controls or restrictions on the remedial activities which are part
of the remedial solution. Action-specific ARARs are triggered by the specific activity rather
than the chemicals present. Location specific ARARs for the SSTS are summarized in Table 2-
2.
2.2.3 Action Specific Requirements
Location-specific ARARs set limitations on remedial activities as a result of the site
characteristics and location. Remedial activities may be limited or restricted based on the site
lo'cation or characteristics. Some action-specific ARARs that may apply to various specific
alternatives analyzed during the FS for the SSTS are summarized in Table 2-3.
2.3 Remedial Action Objectives
CERCLA, as amended by Section 121 (b) of SARA, requires selection of remedial actions to
attain a degree of cleanup that ensures protection of human health and the environment, are cost
effective, and use permanent solutions and alternative treatment technologies or resource
technologies to the maximum extent practicable. To satisfy CERCLA requirements, a set of
recommended RAOs for the SSTS are developed based on the evaluation of the five factors
listed in Section 2.0. The results of those evaluations are described in the OU! RI report (Black
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& Veatch, 2006a), in the additional data evaluations performed in Sections 2.2 and 2.3 of this FS
report, and in discussions with the SSTS risk management team.
2.3.1 Selection of Final Contaminants of Concern
The risk-based COCs identified by the HHRA (see Section 6 of the OU! RI report; Black &
Veatch, 2006a) were reviewed by the SSTS risk management team along with the ARARs, and
other non-risk assessment information. Risk-based COCs found to be of minimal concern to
health or the environment were eliminated from further consideration for remediation. This is
summarized in Table 2-4; the rationale and conclusions of the risk management team decisions
are outlined below.
2.3.1.1 Surface Soil. Vanadium was the only metal in surface soil at the SSTS not screened
by the evaluation of the four factors (see Section 2.1 ). Vanadium was found to be a COC for
human health receptors (e.g., the child resident and the construction worker),vanadium was
found at concentrations above 73 mg/kg (the site-specific risk-based RGO concentration for the
child resident hazard index of!; Appendix M RAGS Part D Table I 1.5 in the OU! RI report
[Black & Veatch, 2006a]) and above 308 mg/kg (the site-specific risk-based RGO concentration
for the on-site construction worker hazard index of 1; Appendix M RAGS Part D Table 11.1
[Black & Veatch, 2006a]).
Several metals in the surface soil were screened from further consideration based on their
concentrations being less than the site-specific, risk-based RGO concentration for surface soil
(aluminum less than 76,865 mg/kg, chromium less than 155 mg/kg, iron with only one
exceedance of22,730 mg/kg, and thallium less than 6 mg/kg; Appendix M RAGS Part D Table
I 1.5 [Black & Veatch, 2006a]). · As discussed in Section 1.5.5, several other metals in the surface
soil were screened from further consideration based on either their leaching potential and/or risk
management discussions with EPA and the State ofNorth Carolina.
2.3.1.2 Subsurface Soil. Some metals (e.g., aluminum, arsenic, barium, manganese,
mercury, and zinc) were not identified as risk-based COCs in subsurface soil but were identified
as groundwater COCs based on their potential for leaching from soil into groundwater. Their
presence in groundwater samples dictated that they be re-evaluated for leaching potential to
shallow groundwater from subsurface soil. As discussed in Section 1.5.6, there are no COCs
based on groundwater protection.
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Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 2
Revision No. 0
March 2006
Page 5 of6
No metals were identified as final COCs in subsurface soil on the basis of direct exposure.
Chromium, iron, and vanadium in subsurface soil were screened from further consideration on
the basis of concentrations not exceeding risk-based RGOs for specific, sensitive receptors or
concentrations being within the distribution.
2.4 General Response Actions and Estimated Volume of
Contaminated Soil
GRAs are generic remedial activities capable of satisfying various RAOs at any number of
CERCLA sites. Identified GRAs that apply to the SSTS include: institutional controls,
monitored natural attenuation, containment of contaminated media to prevent migration to other
locations, excavation/transport/disposal of contaminated media to a controlled location,
treatment of contaminated media to chemically degrade or physically stabilize the contaminants
in place, and treatment of excavated contaminated media into other, less hazardous, forms.
Not all GRAs apply equally to all media; therefore, GRAs were identified for specific media.
The applicability of a GRA depends on a number of factors, one of which is the volume and/or
area of the affected medium. Some GRAs (e.g., containment and access limits) are more
reasonable options for large volumes or areas of contaminated media ( e.g., large mounds of
contaminated material) whereas other GRAs ( e.g., treatment and processing) are more suitable
(e.g., in terms of cost) for small, localized areas or volumes of contaminated media (e.g., small
volumes of surface or subsurface soil). For this reason, areas and volumes of COC-contaminated
media were estimated based on locations and depths of concentrations exceeding RGO
concentrations (Table 2-4), and by using reasonable assumptions of interpolated concentrations
between locations and depths. The estimated areas and volumes of surface and subsurface soil at
the SSTS needing remedial action are listed below:
Surface Soil:
Onsite/Offsite Areas 3,357 cubic yards
Subsurface Soil:
Onsi le Areas 3,867 cubic yards
Stockpile:
Onsite Areas 1,349 cubic yards
Feasibility Study Report -Operable Unit I
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Sigmon's Septic Tank Site
Sludge associated with debris piles
Onsite Areas 400 cubic yards
Total Volume= 8,973 cubic yards
Section 2
Revision No. 0
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Page 6 of6
Contaminated soil areas were estimated based on the. historical and Rl data as shown on Figure
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2-1. Volumes were calculated from these estimated areas based on the depth of the deepest I
contaminant detection exceeding the identified RGOs (Table 2-4).
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Final Feasibility Study Report· Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's S~ptic Tank Site
Section 3
Revision No. I
June 2006
Page I of8
3.0 Identification, Screening, and Evaluation of Technologies
and Process Options
This section presents the identification and screening of technology types and process options
applicable for remediation of contaminated media at the SSTS using the available site
information. The areas to be addressed were considered through the development of applicable
technologies. Potential technologies and process options for contaminated media were identified
and screened to eliminate infeasible or impractical options.
The GRAs for remediation include various containment, removal, treatment (in situ, ex situ, and
offsite), and disposal options. Technologies within these categories have been considered for the
COCs in contaminated media at the SSTS. A preliminary screening of technologies was
conducted on the basis of technical implementability which reduced the wuverse of potentially
applicable technologies. Those technologies that can be technically implemented were further
evaluated on the basis of effectiveness, implementability, and cost. Those technologies retained
for remediation at the site were combined to form remedial action alternatives, presented in
Section 4 and analyzed in detail in Section 5.
3.1 General Response Actions
Based on the established RAOs, site conditions, waste characteristics, and volume of
contaminated media requiring remediation, the selection of technology alternatives for the
remediation of site media were identified. GRAs are those actions that singly or in combination,
satisfy the RA Os for the identified media by reducing the concentration of hazardous substances
or reducing the likelihood of contact with hazardous substances. The GRAs appropriate for
addressing contamination at the SSTS include:
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no action,
institutional controls,
containment,
removal/extraction,
treatment, and
disposal/discharge .
Each GRA was further investigated and screened for specific technologies and process options.
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No Action. The no action response is identified for the purposes of establishing a baseline
against which other GRAs are compared. There would not be any preventive or remedial action
implemented as a result of the no action response, and the current contamination at the site
would continue unabated. However, in accordance with CERCLA Section 121(c), a review/
reassessment of the conditions at the site is required at 5-year intervals to determine if other
remedial action efforts are warranted.
Institutional Controls. Institutional controls are limited actions implemented to reduce the
potential for human exposure to contaminants. Institutional controls may be physical, such as
fences, barriers, or warning signs; or legal, including relocation, zoning, security-restricted
access, deed restrictions or notices upon resale or transfer of title, and notices given to current or
prospective owners or renters. Extended monitoring is also considered an institutional control.
Like the no-action response, these actions would not reduce contaminant concentrations or
protect environmental receptors. The contamination at the site would continue unabated.
Institutional actions may be appropriate at sites where there is a high rate of natural attenuation
of biodegradable contaminants, the contaminants are immobile, the future use risk assessment
scenario does not identify them as a potential future hazard, or when the benefits of cleanup are
·far outweighed by the cost to implement a remedial action. Institutional controls may be ari
appropriate response when used in conjunction with other remedial measures.
Containment. Containment consists of the construction of physical barriers to prevent human
contact with contaminated material and to limit adverse effects on the environment. Common
containment options include capping of contaminated areas and construction of subsurface
barrier walls. Containment is used to isolate the contaminated media and to restrict migration of
the contaminants via soil, water, or air pathways. It does not reduce the concentration or volume
of contaminants. Containment is the presumptive remedy for low-level threat metals-in-soil
wastes.
Removal/Extraction. Removal involves the physical removal of contaminated media from a
site. As a result of such a removal, the area is no longer contaminated (as confirmed by testing
of soil and/or groundwater) and may be restored to use. Removal generally refers to the
excavation of solid media, such as soil or solid/bulk waste 1and/or the extraction of groundwater
via wells. Removal is usually used in conjunction with other technologies, such as treatment or
disposal options, to achieve the RAOs for the removed media. The removal response action does
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Final Feasibility Study Report -Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 3
Revision No. I
June 2006
Pagd of 8
not reduce the concentrations of contaminants in the affected media. It merely transfers the
contaminants to be dealt with under another response action.
Treatment0 Treatment involves the destruction of contaminants in the affected media; transfer
of contaminants from one media to another; or alteration of the contaminants thus making them
innocuous. The result is a reduction in Mobility/ToxicityNolume (M/TN) of the waste.
Treatment technologies vary between environmental media and can consist of chemical,
physical, thermal, and biological processes. Treatment can occur in place or above ground. This
GRA is usually preferred unless site-or contaminant-specific characteristics make it infeasible
from an engineering or implementation sense, or too costly. EPA expects to use treatment to
address the principal threats posed by a site, wherever practicable.
Disposal/Discharge. Disposal involves the transfer of contaminated media, concentrated
contaminants, or other related materials to a site reserved for treatment or long-term storage of
such materials. This generally takes place onsite in an engineered landfill or offsite in an
approved commercial or municipal landfill. Disposal does not reduce the concentration or
volume of waste; it relocates it to a secure area.
Discharge also involves the transfer of contaminated media. It generally refers to the
management of liquids. This response action involves discharging site liquids to an offsite
location, such as a wastewater treatment plant, for disposal or further treatment. It also may
involve onsite discharge via surface water, injection wells, or infiltration galleries.
3.2 Preliminary Screening of Technologies and Process Options
For each GRA there are various remediation methods, or technologies, used to carry out the
response action. The term technology refers to general categories of technology types, such as
thermal treatment. Each technology may have several process options, which refer to the
specific material, equipment, or method used to implement a technology. For example, under the
technology category of thermal treatment for soil, there may be incineration or thermal
desorption process options. These technologies describe broad categories used in remedial
action alternatives but do not address details, such as performance data, associated with specific
process options.
In the initial phase of technology screening, process options and entire technology types were
eliminated from consideration if they were difficult to implement due to their compatibility with
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site characteristics ( e.g., physical features of the site and chemical characteristics of the medium
of concern), or if the technology had not been proven to effectively control the COCs. These
screening criteria were applied based on published information, experience with the technologies
and process options, knowledge of site characteristics, and engineering judgment. Specifically, a
technology or process option was rejected during the initial screening because it:
• would not be a practical method for the volume or area of contaminated media that is to be
remediated;
• would not be an effective method for cleanup of all the contaminants, either as a sole
technology or in combination with another technology, because of characteristics or
concentrations of contaminants present at the site;
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would not be feasible or effective because of site conditions, including conditions such as
location and size, surrounding land use, climate, geology and soils, hydrogeology, and
characteristics of the contaminated media;
could not be effectively administered;
has not been successfully demonstrated for the site contaminants or media; or
has extremely high costs relative to other equally effective technologies .
Table 3-1 describes the process options, present initial screening comments, and summarizes the
technology screening process for contaminated site soil. A description of each process option is
included in the table to provide an understanding of each option and to assist in the evaluation of
its technical implementability. The screening comments address the technical feasibility and
ability of a given process option to serve its intended purpose. The screening comments include
a statement as to whether each process option was retained or rejected. The technologies and
process options listed in the table were selected based on the fate and transport characteristics of
the COCs identified in affected media and on the applicability of a given technology or process
option to the soil. The retained technologies and process options are further evaluated in Section
3.3.
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Final Feasibility Study Report -Operable Unit 1
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Section 3
Revision No. 1
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Page 5 of8
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
3.3 Evaluation of Retained Technologies and Process Options
Incorporation of all process options that survive initial screening into detailed alternatives would
result in a cumbersome number of remedial action alternatives. To reduce that number, process
options that survived initial screening were reevaluated on the basis of effectiveness,
implementability, and cost. In cases where several process options had similar evaluations, a
single process option considered representative of each technology type was selected.
Identifying a representative process option for each technology type was not intended to limit the
process options that could be employed in the remedial design, but instead, provide a basis for
evaluation of a manageable number of alternatives. In some cases, more than one process option
may have been selected for a technology type because the options were sufficiently different in
performance to preclude selecting one as representative of all. The choice of specific process
options for a selected technology can and should be evaluated more completely during the
remedial design phase.
Effectiveness. Specific technology processes were evaluated for their effectiveness in protecting
human health and the environment and in satisfying one or more of the RAOs defined for each
category of media. This evaluation compared the effectiveness of the process options within the
same technology types, while maintaining a variety of technologies needed to develop a range of
alternatives.
This criterion focused on:
•
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the degree to which a process option reduces M/TN through treatment and minimizes
residual risks;
the effectiveness in handling the estimated areas or volume of media and meeting the
RGOs identified;
the effectiveness in protecting human health and the environment during the construction
phase and operation and how quickly it achieves protection;
the degree to which the process option complies with all requirements; and
how proven and reliable the process option is with respect to the contaminants at the site.
Final Feasibility Study Report -Operable Unit I
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Section 3
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Options providing significantly less effectiveness than other, more promising options were
eliminated.
Implementability. This criterion focused on the technical feasibility and availability of the
option and the administrative feasibility of implementing the option. During the first screening,
process options that were ineffective or unworkable at the site were eliminated as being
technically infeasible. The secondary screening continued the evaluation on a more detailed
level, placing greater emphasis on the institutional aspects. Implementability considered:
• availability of treatment, storage, and disposal services as well as capacity, and
• availability of necessary equipment and skilled workers to implement the technology.
Options that were technically or administratively infeasible or that would require equipment,
specialists, or facilities that are not available within a reasonable period of time were eliminated
from further consideration.
Cost. The costs of construction and any long-term costs associated with operation and
maintenance (O&M) were considered. Costs that were excessive compared to the overall
effectiveness of options was considered as one of several factors used to eliminate optio~s.
Options providing effectiveness and implementability similar to those of another option by
employing a similar method of treatment or engineering control, but at a greater cost, were
eliminated. It should be noted that the greatest cost variability during site remediation is
generally seen between the technology types, rather than within specific process options in a
given technology.
Relative costs are used rather than detailed estimates. At this stage in the process, the cost
analyses are subjectively made on the basis of engineering judgment. Each process option was
evaluated as to whether costs are high, moderate, or low relative to other process options of the
same technology groups. In terms of dollars, cost_ ranges with ~espect to total cost consisted of
• high= >$2 million,
• moderate = $500,000 to $2 million, and
• low= <$500,000.
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon' s Septic Tank Site
Section 3
Revision No. I
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The evaluation of the retained technologies and process options based on effectiveness,
implementability, and cost for contaminated site soils is presented in Table 3-2. A summary of
the retained technologies and process options is presented in Table 3-3. These technologies and
process options were used in the development of the remedial action alternatives as presented in
Chapter 4.
After the initial screening presented in Table 3-2, several process options were eliminated from
further analysis as follows.
Contaminated Soils. In-situ soil flushing was eliminated because of problems with
implementability due to the site geology that includes impermeable layers, residual flushing
additives in the soil may be a concern, and the technology would require the construction of
slurry walls, collection wells or subsurface drains. In situ solidification and stabilization also
was eliminated from further consideration due to the spatial distribution of inorganic
contamination encompassing both onsite and offsite areas of the site making this technology
impractical, and since in situ treatment introduces chemical agents into the ground which may
cause a pollution problem in itself. In situ vitrification was eliminated from further consideration
because of the large surface areas ana relatively shallow depths of site contamination make other
technologies more efficient.
In considering the ex situ treatment technologies, RCRA Hazardous Waste Treatment Facility
was eliminated because offsite treatment may not be the most cost effective solution since onsite
treatment is a feasible alternative. Pyrometallurgical processing was eliminated because it
requires uniform high concentration feed materials to be cost effective. Vitrification was
eliminated because of its uncertain ability to treat site contaminants and its high capital and
O&M costs. Soil washing was eliminated because its implementability may be problematic for
several reasons. For example, most extraction solutions are effective only for a narrow range of
metals and matrix combinations; therefore, a single target metal would be preferable to multiple
metals. Finally, creation of an onsite RCRA landfill was eliminated from further consideration
because of space requirements, the need for compliance with state landfill siting requirement, as
well as permanent restrictions on future land use and long-term maintenance.
Final Feasibility Study Report -Operable Unit I
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Work Assignment No. 340-RICO-A44F
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Table 3-3
Section 3
Revision No. I
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Page 8 of8
Summary of Retained Technologies and Process Options
Sigmon's Septic Tank Site -Statesville, North Carolina
Contaminated Soil
General Response
Action Remedial Technolouv Process Option
No Action None Not Annlicable
Institutional Controls Access and Use Restrictions Land Use Restrictions
Deed/Zoning Restrictions
Fencing
Environmental Monitorin~ Air, Soil, and/or Groundwater
Removal Excavation A II processes
Ex-Situ Treatment-Physical/Chemical Solidification/Stabilization/
Immobilization Fixation/Composting
Disposal Offsite Subtitle D Landfill
Onsite Disoosal of Treated Material Onsite
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Final Feasibility Study Rt:port -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
4.0 Development and Screening of Alternatives
Section 4
Revision No. I
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Page I of 7
The objective of this section is to combine the list of previously screened technologies and
process options to form a range of remedial action alternatives for the SSTS. To address the site-
specific RAOs, a variety of alternatives were formulated by combining the retained technologies
in Section 3.3. The range of alternatives for contaminated soil includes no action, institutional
controls, containment, removal, treatment, and disposal options.
In formulating alternatives, contaminants with concentrations above remediation goals,
applicable technologies, and the contaminants which these technologies most effectively address
were considered. The goal in developing remedial action alternatives is to provide a range of
cleanup options together with sufficient information to adequately compare alternatives against
each other.
Each alternative developed and described in this section was evaluated to determine its overall
effectiveness, implementability, and cost. These criteria for alternative evaluation are similar to
that previously used to evaluate the process options. The use of effectiveness, implementability,
and cost as evaluation criteria has been defined in Section 3 .3.
After each criterion was evaluated, RAs with the most favorable overall evaluations were
retained to undergo detailed analysis. The screening procedure attempts to maintain
representative alternatives from a full range of technologies. Those alternatives not selected may
be considered at a later step during the design stage if information is developed that identifies an
additional advantage not previously apparent or an alternative for a similar retained alternative
that continues to be evaluated favorably.
4.1 Soil Alternatives Analysis
A summary of the developed alternatives for the SSTS is presented in Table 4-1 for solid media
(soil). The alternatives that were selected for soil at the SSTS include no action, excavation with
solidification/stabilization and onsite disposal, and excavation with solidification/stabilization
and off-site disposal.
Final Feasibility Study Report -Operable Unit I
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Table 4-1
Development Of Remedial Action Alternatives For Soil
Sigmons Septic Tank Site -Statesville, North Carolina
Alternative Description of Alternative
I No Action
Section 4
Revision No. I
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Page 2 of 7
2 Excavation, On-Site Treatment with Solidification/Stabilization and On-Site Disposal of
Treated Waste
Excavate contaminated soil
Consolidate material on-site and treat by solidification/stabilization
Excavate on-site disposal area
Dispose of treated material back into on-site excavated area
Media monitoring
3 Excavation, On-Site Treatment with Solidification/Stabilization and Off-Site Disposal of
Treated Waste
Excavate contaminated soil
Consolidate material on-site and treat by solidification/stabilization
Dispose of treated material into offsite RCRA Subtitle D landfill
Media monitoring
Note:
For the purpose of developing treatment-based alternatives involving immobilization technologies, the terms
"solidification" and "stabilization" are used. However, other immobilization technologies, such a fixation, or other
physical or chemical reaction/interaction such as biosolid composting, which prevents solubilization of contaminants
and limits the bioavailability of contaminants also may be appropriate for consideration.
4. 1. 1 Alternative 1-No Action
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4.1.1.1 Description. Under this alternative, no action would be taken to remedy the
contaminated soil or other solid media at the site. The alternative would only involve the I
continued monitoring of soil at the site. Approximately 15 soil samples would be collected from
the affected areas and analyzed for the COCs found in each medium every five years for 30
years. Public health evaluations would be conducted every five years and would allow EPA to
assess the ongoing risks to human health and the environment posed by the SSTS. The
evaluations would be based on the data collected from media monitoring.
4.1.1.2 Effectiveness. The no action alternative is required by the NCP to be carried through
the screening process, as it serves as a baseline for comparison of the site remedial action
alternatives. This alternative does not reduce the exposure of receptors to site contaminants.
Continued migration of contaminants and the resulting exposure of receptors would occur. As a
result, this alternative is not effective in protecting human health or the environment, or reducing
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Final Feasibility Study Report• Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
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Section 4
Revision No. I
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Page 3 of 7
M/T/V of contaminants at the site. Monitoring proposed under this alternative would allow EPA
to assess the ongoing threats to human health and the environment posed by the site.
4. 1.1.3 Implementability. The only task which would require implementation under this
alternative is the periodic media monitoring at the site. This alternative could be easily
implemented since monitoring equipment is readily available and procedures are in place.
4.1.1.4 Cost. Minimal costs are associated with this alternative relative to other remedial
action alternatives. No capital costs are associated with this alternative. There will be annual
O&M costs for media sampling associated with the monitoring.
4.1.2 Alternative 2-Excavation and On-Site Treatment With Solidification/
Stabilization and On-Site Disposal of Treated Waste
4.1.2. 1 Description. Contaminated soil throughout the site would be excavated and
consolidated. Confirmation sampling and analysis would be performed to ensure that the
cleanup goals are met for all contaminants.
Solidification/Stabilization (S/S) technology would be used to treat the contaminated soil.
Contaminants within soil would be physically bound or enclosed within a stabilized mass
(solidification), or chemical reactions would be induced between a stabilizing agent and the
contaminant to reduce its mobility (stabilization). S/S treatment technologies include the
addition of cement, lime, pozzolan, or silicate-based additives, or chemical reagents that
physically or chemically react with the contaminant. Once treated and confirmed to be
nonhazardous, the soil would be consolidated and disposed of in an onsite, unlined excavation.
The onsite disposal area would be about 300 feet long, 200 feet wide and 4.25 feet deep. A I-
foot soil cover consisting of uncontaminated soil excavated from the disposal area would be
placed over the disposal cell. A 6-inch topsoil layer would be placed over the entire site.
The components of this alternative are outlined as follows:
• Excavation of contaminated soil (8,600 yd') plus an additional 400 yd' associated with existing onsite
debris piles for a total of9,000 yd'.
• Confirmation sampling and analysis of the excavated areas to ensure that the cleanup goals are met.
• Stabilization or solidification of contaminated soil (approximately 9,000 yd3).
Final Feasibility Study Report· Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RJCO-A44F
Sigmon's Septic Tank Site
• Excavation of onsite disposal area (9,500 yd').
Section 4
Revision No. 1
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Page 4 of 7
• Compaction of 9,500 yd' of waste; assuming a 5% increase m soil volume due to
stabilization/solidification.
• Backfill of clean soil into areas where contaminated soil and sediment were removed {9,000 yd').
• Place a I-foot clean soil cover over the disposal site (2,200 yd').
• Place a 6 inch topsoil cover and grass seeding over disposal cell and soil excavation areas (3.5 acres).
• Land use/deed restrictions and fencing:
Alternative 2 would eliminate direct contact with contaminated media, eliminate onsite physical
hazards, and eliminate contaminant migration to groundwater and surface water from the site.
The final treatment system would depend upon the outcome of treatability testing and would be
determined during the remedial design phase. The fixed material would be subjected to SPLP
testing to determine if treatment has been effective, prior to placement in the excavated disposal
area.
Treatability testing may be required to demonstrate contaminant immobilization for this
treatment process and to help determine the volume mcrease caused by the
solidification/stabilization process.
Deed restrictions may be placed on the site while the remedial action takes place. Monitoring
would be required to assess the effectiveness of the remedial action.
4.1.2.2 _Effectiveness Under this alternative, contaminated media would be treated and
converted to a nonhazardous, nonleachable material and buried on site. Migration of hazardous
contamination to groundwater would be eliminated because the treated, buried material would
effectively bind or bond the contaminants, preventing leaching and contaminant migration. This
combination of technologies would ensure that the selected treatment system would remediate
surface soil and sediment contamination to concentrations meeting remediation goals, and RAOs
would be met. Excavation and onsite treatment permanently eliminates the long-term health and
environmental risks at the site, as well as reducing contaminant mobility.
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Final Feasibility Study Report -Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RJCO-A44F
Sigmon's Septic Tank Site
Section 4
Revision No. I
June 2006
Page 5 of 7
4.1.2.3 Implementability. Treatment of contaminated soil and sediments is offered by
numerous vendors. Onsite treatment utilizes standard construction practices and material
handling equipment. No significant construction issues are expected to be encountered.
Treatment of the contaminated waste will likely increase the volume of the waste soil and
sediment material; however, slight volume reductions may occur when some chemical reagents
are used to treat the material. Typical volume increases range from about 5 percent to as high as
I 00 percent, depending upon the treatment method used. An increase in the volume of the
treated waste material will have an impact on the disposal volume required. Calculations used in
the development of this alternative utilized a volume increase estimate of 5 percent.
Wastewater may be generated during implementation of this alternative through water runoff
generated as a result of dust emission control. Wastewater may also be generated as a result of
decontamination activities required for equipment and on-site workers. Containment and
treatment or disposal of these wastewaters may be required. Depending upon the treatment
methodology selected, the wastewater may be able to be utilized in the soils treatment process.
4. 1.2.4 Cost. Moderate to high costs are associated with this alternative relative to other
remedial action alternatives. Typical expenditures would include capital costs for equipment and
construction of the treatment system, as well as excavation.
4.1.3 Alternative 3-Excavation and On-Site Treatment With Solidification/
Stabilization and Off-Site Disposal of Treated Waste
4.1.3.1 Description. Alternative 4 is similar to Alternative 3 except that the S/S treated soil
and sediment will be disposed offsite. The specific components of this alternative are outlined
as follows:
• Excavation of contaminated soil (8,600 yd3) plus an additional 400 yd3 associated with existing
onsite debris piles for a total of9,000 yd3.
• Confirmation sampling and analysis of the excavated areas to ensure that the cleanup goals are met.
•
•
Stabilization or solidification of contaminated soil (approximately 9,000 yd3l .
Off-site disposal of the treated material at a nonhazardous disposal facility 9,500 yd3 (assuming a
5 percent increase in volume during treatment).
Final Feasibility Study Report -Operable Unit l
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 4
Revision No. I
June 2006
Page 6 of 7
• Backfill of clean soil into areas where contaminated soil and sediment were removed (9,000 yd\
• Place a 6 inch topsoil cover and grass seeding over the soil excavation areas (2.5 acres).
Alternative 3 would eliminate direct contact with contaminated media, eliminate onsite physical
hazards, and eliminate contaminant migration to groundwater and surface water from the site.
Deed restrictions may be placed on the site while the remedial action takes place. Monitoring
would be required to assess effectiveness of the remedial action.
4.1.3.2 Effectiveness. Under this alternative, contaminated media would be treated and
converted to a nonhazardous, nonleachable material and transported to an offsite disposal
facility. Migration of hazardous contamination would be eliminated because the material
containing contaminant concentrations above the cleanup goals would be treated and removed
from the site. This combination of technologies would ensure that the selected treatment system
would remediate surface soil to concentrations meeting remediation goals, and RAOs would be
met. Excavation and onsite treatment with offsite disposal permanently eliminates the long-term
health and environmental risks at the site. This alternative would ensure that the surface soil and
sediment concentrations would meet remediation goals and RAOs.
4.1.3.3 Implementability. Treatment of contaminated soil and sediment is offered by
numerous vendors. Onsite treatment utilizes standard construction practices and material
handling equipment. No significant construction issues are expected to be encountered.
Implementation of this process option is considered technically feasible and could be readily
implemented. Access to Subtitle D facilities also is available.
Treatment of the contaminated waste will likely increase the volume of the waste soil and
sediment material; however, slight volume reductions may occur when some chemical reagents
are used to treat the material. Typical volume increases range from about 5 percent to as high as
100 percent, depending upon the treatment method used. An increase in the volume of the
treated waste material will have an impact on the disposal volume required. Calculations used in
the development of this alternative utilized a volume increase estimate of 5 percent.
Wastewater may be generated during implementation of this alternative through water runoff
generated as a result of dust emission control. Wastewater may also be generated as a result of
decontamination activities required for equipment and on-site workers. Containment and
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Final Feasibility Study Report -Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 4
Revision No. I
June 2006
Page 7 of 7
treatment or disposal of these wastewaters may be required. Depending upon the treatment
methodology selected, the wastewater may be able to be utilized in the soils treatment process.
As is the case for Alternative 2, treatability testing may be required to demonstrate contaminant
immobilization for this treatment process and to help determine the volume increase caused by
the solidification/stabilization process.
4.1.3.4 Cost. High costs are associated with this alternative, as a result of offsite disposal
costs and transportation of the waste to a disposal facility. Capital costs include equipment for
excavation of the contaminated material and the purchase of clean fill. In addition, monitoring
costs associated with excavation verification are realized costs.
4.2 Screening of Soil Alternatives for Further Evaluation
4.2.1 Effectiveness
Alternative I is not effective in achieving any of the RAOs. Alternative 2 can partially meet
RAOs by reducing risks associated with exposure pathways; however, at least some
contaminated material still remains onsite. Alternative 3 is potentially effective in achieving
RAOs.
4.2.2 Implementability
All of the alternatives are implementable. Alternative I is easiest to implement, followed by
Alternatives 3 and 2.
4.2.3 Cost
Alternative I is the least costly of all of the alternatives, followed by Alternatives 2 and 3.
4.3 Selection of Soil Alternatives for Further Evaluation
Alternative I (no action) is retained for detailed analysis as required by the NCP. This
alternative serves as a baseline for decision makers to evaluate the other alternatives.
Alternatives 2 and 3 are retained for further consideration since they can achieve RAOs through
treatment.
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
5.0 Detailed Analysis of Alternatives
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Page I of 12
In accordance with the National Contingency Plan (NCP), the retained alternatives for soil
described in Section 4 were evaluated against the nine criteria as described below.
Overall Protection of Human Health and the Environment
Each alternative was assessed to determine whether it can adequately protect human health and
the environment,, in both the short-and long-term, from unacceptable risks posed by hazardous
substances, pollutants, or contaminants present at the site by eliminating, reducing, or controlling
exposures to levels established during development of remediation goals. Overall protection of
human health and the environment draws on the assessments of other evaluation criteria,
especially long-term effectiveness and permanence, short-term effectiveness, and compliance
with ARARs.
Compliance with ARARs
Each alternative was assessed to determine whether it will attain ARARs under federal and state
environmental or facility siting laws, or provide grounds for invoking one of the waivers.
Long-Term Effectiveness and Permanence
Each alternative was assessed for the long-term effectiveness and permanence it presents, along
with the degree of certainty that the alternative will prove successful. Factors considered as
appropriate included the following:
• Magnitude of residual risk remaining from untreated waste or treatment residuals remaining
at the conclusion of the remedial activities. The characteristics of the residuals are
considered to the degree that they remain hazardous, taking into account their M/T/V and
propensity to bioaccumulate.
• Adequacy and reliability of controls such as containment systems and institutional controls
that are necessary to manage treatment residuals and untreated waste. This factor addresses
the uncertainties associated with land disposal for providing long-term protection from
residuals; the assessment of the potential need to replace technical components of the
alternative; and the potential exposure pathways and risks posed should the remedial action
need replacement.
Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigrnon's Septic Tank Site
Reduction of MITIV Through Treatment
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The degree to which each alternative employs recycling or treatment that reduces MITN was
assessed, including how treatment is used to address the principal threats posed by the site.
Factors considered as appropriate included the following:
• the treatment or recycling processes the alternatives employ and the materials they will treat;
• the amount of hazardous substances, pollutants, or contaminants that will be destroyed,
treated, or recycled;
• the degree of expected reduction of M/TN of the waste due to treatment or recycling and
the specification of which reduction(s) are occurring;
• the degree to which the treatment is irreversible;
• the type and quantity of residuals that will remain following treatment, considering the
persistence, toxicity, mobility, and propensity to bioaccumulate such hazardous substances
and their constituents; and
• the degree to which treatment reduces the inherent hazards posed by principal threats at the
site.
Short-Term Effectiveness
The short-term effectiveness of each alternative was assessed considering the following:
• short-term risks that might be posed to the community during implementation of an
alternative;
• potential impacts on workers during remedial action and the effectiveness and reliability of
protective measures;
• potential environmental impacts of the remedial action and the effectiveness and reliability
of mitigation measures during implementation; and
• time until protection is achieved.
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Implementability
Section 5
Revision No. I
June 2006
Page 3 of 12
The ease or difficulty of implementing each alternative was assessed by considering the
following types of factors as appropriate:
• Technical feasibility, including technical difficulties and unknowns associated with the
construction and operation of a technology, the reliability of the technology, ease of
undertaking additional remedial actions, and the ability to monitor the effectiveness of the
remedy.
• Administrative feasibility, including activities needed to coordinate with other offices and
agencies and the ability and time required to obtain any necessary approvals and permits
from other agencies ( e.g., off-site disposal).
• Availability of services and materials, including the availability of adequate off-site
treatment, storage capacity, and disposal capacity and services; the availability of necessary
equipment and specialists, and provisions to ensure any necessary additional resources; the
availability of services and materials; and availability of prospective technologies.
Cost
• The types of costs that were assessed include the following:
• Capital costs, including both direct and indirect costs;
• Annual O&M; and
• Net present worth of capital and O&M costs.
The present worth of each alternative provides the basis for the cost comparison. The present
worth cost represents the amount of money that, if invested in the initial year of the remedial
action at a given rate, would provide the funds required to make future payments to cover all
costs associated with the remedial action over its planned life.
The present worth analysis was performed on all remedial alternatives using a 7% discount rate
over a period of 30 years. Inflation and depreciation were not considered in preparing the
Final Feasibility Study Report -Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RJCO-A44F
Sigmon's Septic Tank Site
Section 5
RcvisiOn No. 1
June 2006
Page 4 of12
present worth costs. Appendix C contains spreadsheets showing each component of the present
worth costs.
State Acceptance
Assessment of State concerns will not be completed until comments on the FS report are
received but may be discussed, to the extent possible, in the proposed plan issued for public
comment. The State concerns that shall be assessed include the following:
• the State's position and key concerns related to the preferred alternative and other
alternatives; and
• State comments on ARARs.
Community Acceptance
This assessment includes determining which components of the alternatives interested persons in
the community support, have reservations about, or categorically reject. This assessment will not
be completed until comments on the proposed plan are received.
In order to establish priority among these criteria, they are separated into three groups. The first
two criteria listed are threshold criteria and must be satisfied by the remedial action alternative
being considered. The next five criteria are secondary criteria used as balancing criteria among
those alternatives which satisfy the threshold criteria. The last two criteria are not evaluated
during the FS. State and community acceptance is evaluated by EPA during the public comment
period of the proposed plan, and an EPA responsiveness summary is incorporated into the ROD.
The objective of this section is to evaluate each of the alternatives for site remediation,
individually on the basis of the threshold and balancing criteria. A summary of this analysis for
soil is presented in Table 5-1. A comparative analysis of how the seven criteria are satisfied by
each of the alternatives is presented in Chapter 6.
In accordance with the NCP, the retained alternatives described in Section 4 were evaluated
against the nine criteria. However, the description for the cost criteria has been modified as
listed below:
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Cost
The types of costs that were assessed include the following:
• Capital costs (those expenditures that are required to construct a remedial action),
Section 5
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• O&M costs (post-construction costs necessary to ensure or verify the continued
effectiveness of a remedial action), and
• Periodic costs (those costs that occur only once every few years or expenditures that occur
only once during the. entire O&M period or remedial time frame).
The costing for this feasibility study was performed in accordance with A Guide to Developing
and Documenting Cost Estimates During the Feasibility Study (EPA 2000).
The present worth of each alternative provides the basis for the cost comparison. The present
worth cost represents the amount of money that, if invested in the initial year of the remedial
action at a given rate, would provide the funds required to make future payments to cover all
costs associated with the remedial action over its planned life.
The present worth analysis was performed on all remedial alternatives using a 7% discount rate
over a period of 30 years. Inflation and depreciation were not considered in preparing the
present worth costs. Appendix A contains spreadsheets showing each component of the present
worth costs.
5.1 Analysis of Soil and Sediment Alternatives
Three of the four alternatives were carried through the screening process presented in Section 4.
These alternatives are:
• Alternative 1
• Alternative 2
• Alternative 3
No Action
Excavation, Onsite Treatment With Solidification/ Stabilization, and On-
Site Disposal of Treated Waste
Excavation, Onsite Treatment With Solidification/ Stabilization, and Off-
Site Disposal of Treated Waste
Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon 's Septic Tank Site
Section 5
Revision No. I
June 2006
Page 6 of 12
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Those alternatives not selected may be reconsidered at a later step during the remedial design I
phase if information is developed that identified an additional advantage not previously apparent,
or as an alternative for a similar retained alternative that continues to be evaluated favorably.
5.1.1 Alternative 1-No Action
Overall Protection of Human Health and the Environment
The no action alternative does not eliminate any exposure pathways or reduce the level of risk of
the existing soil contamination.
Compliance with ARARs
This alternative does not achieve the RAOs or chemical-specific ARARs established for surface
soil. Location-and action-specific ARARs do not apply to this alternative since further remedial
actions will not be conducted.
Long-Term Effectiveness and Permanence
The remediation goals derived for protection of human health and the environment would not be
met. Because contaminated soil remains under this alternative, a review/reassessment of the
conditions at the site would be performed at 5-year intervals to ensure that the remedy does not
become a greater risk to human health and the environment.
Reduction of M/T/V Through Treatment
No reductions in contaminants' MITN are realized under this alternative.
Short-Term Effectiveness
Since no further remedial action would be implemented at this site, this alternative poses no
short-term risks to on-site workers. · It is assumed that Level D personal protective equipment
would be used when sampling various media.
Implementability
This alternative could be implemented immediately smce monitoring equipment 1s readily
available and procedures are in place.
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Sitt:
Cost
The total present worth cost for this alternative 1s approximately $72,000.
estimates are presented in Appendix A.
5.1.2 Alternative 2-Excavation, Onsite Treatment With Solidification/ Stabilization, and Onsite Disposal of Treated Waste Overall Protection of Human Health and the Environment
Section 5
Revision No. I
June 2006
Page 7 of 12
Detailed cost
Successful implementation of this alternative would eliminate risks to human health and the
environment and meet the removal action objectives by (I) eliminating exposure of residents and
trespassers to waste material by direct contact and airborne migration, (2) eliminating exposure
of trespassers to direct contact with on-site physical hazards, and (3) eliminating the migration of
contaminants to groundwater and surface water. The threat of direct human exposure to
contaminated waste and physical hazards would be eliminated by this alternative. Treatment of
the waste material would eliminate contaminant exposure through the receptor routes of
ingestion and inhalation. Contaminated soil would be treated and converted to a nonhazardous
material. Waste immobilized by treatment or removed by decontamination would eliminate
contaminant migration from the site.
Compliance with ARARs
If the treated soils are disposed on site, a cap consisting of at least 6 inches of asphalt or at least
12 inches of compacted soil is required. The other standards of the State of North Carolina
included in Table 2-5, Water Quality Criteria Standards and Water Pollution Control
Regulations, will be complied with if stabilization precludes leaching hazardous constituents
from the solidified or stabilized mass.
Long-Term Effectiveness and Permanence
If the disposal area is classified as a Class II disposal facility, the area may have to be maintained
to ensure that it continues to perform as designed; consequently, monitoring, inspection, and
maintenance would be required. The soil cover area would be susceptible to settlement, ponding
of-surface water, erosion, and disruption of cover integrity by deep-rooting vegetation and
burrowing animals. However, the cover would be periodically inspected, and required
maintenance could be implemented.
If the SSTS is not classified as a Class II disposal facility; monitoring, inspection, and
maintenance may not be required. Treatment reagents are typically tested by the Multiple
Extraction Procedure (MEP, SW-846 Method 1320) to measure long-term stability. The test is
Final Feasibility Study Report· Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 5
Revision No. 1
June 2006
Page 8 of 12
intended to approximate leachability under acidic cond!tions over a 1,000-year time frame.
Based on successful completion of bench-scale testing that would include MEP analysis, this
alternative is expected to provide adequate long-term effectiveness and permanence. Access
restrictions such as land use controls and fencing m~y be required to prevent/ land uses
incompatible with the site.
Reduction of M/T/V Through Treatment
The primary objective of this alternative is to reduce COl)-taminant toxicity and mobility through
treatment; contaminant volume would not be reduced. Contaminant toxicity would be reduced
by altering the physical or chemical structure of the cont[!J11inant into a nonhazardous material.
Contaminant mobility would be reduced by binding or bonding the contaminant into a
nonleachable form that would eliminate contaminant migration from the site. Conta¾inant
mobility is expected to be reduced to an extent that woul,d result in overall risk reduction from all
pathways and exposure routes.
Short-Term Effectiveness
The construction phase of this alternative would likely be accomplished within one field season;
therefore, impacts associated with construction would likely be short term and minimal. Short-
term impacts are associated with excavation, consolidation, and treatment of waste soil and
sediment; however, these potential, short-term impacts would be mitigated during the
construction phase.
If the excavated material is dry, on-site workers will be exposed to waste soil and sediment dust
during excavation and consolidation activities. Ingestion of dust could involve some health
effects because of the high level of metals in waste soils.
Onsite workers would be adequately protected fro/n short-term risks by using appropriate
personal protective equipment and by following proper operating and safety proce(\ures.
However, short-term air quality impacts to the surrounding environment may occur during waste
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consolidation and grading. Dust emissions would /be monitored at the property boundaries.
Fugitive dust emissions would be controlled by applying water as needed to surfaces receiving
heavy vehicular traffic or in excavation areas. A measurable, short-term impact. to the
surrounding area would include increased vehicular traffic and associated safety hazards,
potential dust generation, and noise.
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Final Feasibility Study Report -Operable Unit I EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Implementability
Section 5
Revision No. I
June 2006
Page 9 of 12
Treatment of contaminated soil and sediment is offered by numerous vendors. On-site treatment
utilizes standard construction practices and material handling equipment. No significant
construction issues are expected to be encountered.
Treatment of the contaminated waste will likely increase the volume of the waste soil and
sediment material; however, slight volume reductions may occur when some chemical reagents
are used to treat the material. Typical volume increases range from about 5 percent to as high as
I 00 percent, depending upon the treatment method used. An increase in the volume of the
treated waste material will have an impact on the disposal volume required. Calculations used in
the development of this alternative utilized a volume increase estimate of 5 percent.
Wastewater may be generated during implementation of this alternative through water runoff
generated as a result of dust emission control. Wastewater may also be generated as a result of
decontamination activities required for equipment and on-site workers. Containment and treatment or disposal of these wastewaters may be required. Depending upon the treatment
methodology selected, the wastewater may be able to be utilized in the soils treatment process.
The on-site disposal area for the treated waste may be classified as a Class II disposal facility. If
so, the substantive requirements -of the Solid Waste Processing and Disposal (SWPD) rule regarding Class II disposal facilities would apply to the site.
All services and materials for this alternative are readily available.
Cost
The total present worth cost for this alternative is approximately $2.2 million. Estimated capital costs are $2 million and estimated O&M costs are $220,000. Detailed cost estimates are presented in Appendix A.
5.1.3 Alternative 3-Excavation, On-Site Treatment With Solidification/ Stabilization, and Off-Site Disposal of Treated Waste Overall Protection of Human Health and the Environment
Successful implementation of this alternative would eliminate risks to human health and the
environment and meet the RA Os by (I) eliminating exposure of residents and trespassers to
Final Feasibility Study Report • Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 5
Revision No. 1
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Page 10 of 12
waste material by direct contact and airborne migration, (2) eliminating exposure of trespassers
to direct contact with on-site physical hazards, and (3) eliminating the migration of contaminants
to groundwater and surface water. The threat of direct human exposure to contaminated waste
and physical hazards would be eliminated by this alternative. Treatment and removal of the
waste material would eliminate contaminant exposure through the receptor routes of ingestion
and inhalation. Contaminated soil and sediment would be treated and converted to a
nonhazardous material and transported to an off-site disposal facility. Structures throughout the
site would be demolished and either disposed of in an excavated disposal area beneath the
existing pavement or recycled. As a result, physical hazards associated with deteriorating
structures would be eliminated. Removal of waste would mitigate contaminant migration from
the site.
Compliance with ARARs
Transportation of treated soils would be in accordance with applicable Department of
Transportation (DOT) hazardous material regulations. Disposal at a RCRA-permitted Subtitle D
landfill would be in compliance with ARARs ..
Long-Term Effectiveness and Permanence
Treatment and removal of the waste material would not require monitoring, inspection, or
maintenance for the site. Treatment reagents are typically tested by MEP SW-846 Method 1320
to measure long-term stability. The test is intended to approximate leachability under acidic
conditions over a 1,000-year time frame. Based on successful completion of bench-scale testing
that would include MEP analysis, this alternative is expected to provide adequate long-term
effectiveness and permanence. Access restrictions such as land use controls and fencing would
likely not be required.
Reduction of Mll/V Through Treatment
The primary objective of this alternative is to reduce contaminant toxicity and mobility through
treatment; contaminant volume would not be physically reduced. Contaminant toxicity would be
reduced by altering the physical or chemical structure of the contaminant into a nonhazardous
material. Contaminant mobility would be reduced by binding or bonding the contaminant into a
nonleachable form. Subsequent removal would mitigate contaminant migration from the site.
Contaminant volume would not be physically reduced under this alternative.
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Final Feasibility Study Report -Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Short-Term Effectiveness
Section 5
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June 2006
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The construction phase of this alternative would likely be accomplished within one field season; therefore, impacts associated with construction would likely be short term and minimal. Short-term impacts are associated with excavation, consolidation, and treatment of waste soil; however, these potential, short-term impacts would be mitigated during the construction phase.
If the excavated material is dry, on-site workers will be exposed to waste soil dust during excavation and consolidation activities. Ingestion of dust could involve some health effects because of the high level of metals in waste soil.
On-site workers would be adequately protected from short-term risks by usmg appropriate
personal protective equipment and by following proper operating and safety procedures.
However, short-term air quality impacts to the surrounding environment may occur during waste consolidation and grading, and transportation of treated waste for offsite disposal. Monitoring of dust emissions would be monitored at the property boundaries. Fugitive dust emissions would be controlled by applying water as needed to surfaces receiving heavy vehicular traffic or in excavation areas. A measurable, short-term impact to the surrounding area would include increased vehicular traffic and associated safety hazards, potential dust generation, and noise.
Implementability
Treatment of contaminated soil and sediment is offered by numerous vendors. On-site treatment utilizes standard construction practices and material handling equipment. No significant
construction issues are expected to be encountered.
Treatment of the contaminated waste will likely increase the volume of waste soil and sediment
material; however, a slight volume reduction may occur if a chemical reagent is used to treat the material. Typical volume increases range from about 5 percent to as high as 100 percent, depending upon the treatment methodology used. An increase in the volume of the treated waste material will have an impact on the transportation costs to a disposal facility. Calculations used in the development of this alternative assume a volume increase of 5 percent.
Wastewater may be generated during implementation of this alternative through water runoff
generated as a result of dust emission control. Wastewater may also be generated as a result of decontamination activities required for both equipment and on-site workers. Containment and
Final Feasibility Study Report• Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 5
Revision No. 1
June 2006
Page 12 of 12
treatment or disposal of these wastewaters may be required. Depending upon the treatment
methodology selected, the wastewater may be able to be utilized in the soils treatment process.
No state or federal permits are expected to be required; however, advance consultation should
occur in planning the action to ensure that all involved agencies are allowed to provide input.
All services and materials for this alternative are readily available.
Cost
The total present worth cost for this alternative is approximately $3.8 million. Estimated capital
costs are $3.6 million and estimated O&M costs are $200,000. Detailed cost estimates are
presented in Appendix A.
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Final Feasibility Study Report -Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RlCO-A44F
Sigmon's S~ptic Tank Site
6.0 Comparative Analysis of Alternatives
Section 6
Revision No. I
June 2006
Page 1 of 1
This section presents a comparative analysis of the soil alternatives based on the threshold and
balancing evaluation criteria. The objective of this section is to compare and contrast the
alternatives so that decision makers may select a preferred alternative for presentation in the
ROD.
The alternatives are presented here to give decision makers a range of potential actions that could
be taken to remediate this site.
For soil/sediment, these actions include:
• No action,
•
•
Excavation, on-site treatment with solidification/stabilization, and on-site disposal of
treated waste, and
Excavation, on-site treatment with solidification/stabilization, and off-site disposal of
treated waste.
Table 6-1 presents a summary of each soil remedial alternative along with ranking scores for
each evaluation criterion. Each alternative's performance against the criteria (except for present
worth) was ranked on a scale ofO to 5, with O indicating that none of the criterion's requirements
were met and 5 indicating all of the requirements were met. The ranking scores are not intended
to be quantitative or additive, but rather are only summary indicators of each alternative's
performance against the CERCLA evaluation criteria. The ranking scores combined with the
present worth costs provide the basis for comparison among alternatives.
Alternatives 2 and 3 ranks higher than Alternative I in overall protection of human health and
the environment, compliance with ARARs, long-term effectiveness and permanence, and
reduction of M/T/V. Alternative 3 ranks slightly higher than Alternative 2 in compliance with
ARARs, long-term effectiveness and permanence, and implementability. Alternative 2 ranks
slightly higher than Alternative 3 in short-term effectiveness.
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Final Feasibility Study Report· Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
7.0 References
Section 7
Revision No. I
June 2006
Pagel of6
Black & Veatch, 2001a. Letter to Giselle Bennett, EPA Region 4, from Christopher J. Allen,
Black & Veatch Special Projects Corp., dated October 1, 2001. Subject: Site Visit Letter
Report
Black & Veatch, 2001b. Memorandum to File, from Christopher J. Allen, Black & Veatch
Special Projects Corp., dated December 7, 2001. Subject: Phone Memos.
Black & Veatch, 2002a, Black & Veatch Special Projects Corp. Revised Final Sampling and
Analysis Plan, Volume I-Quality Assurance Project Plan Remedial Investigation, Volume 2-
Field Sampling Plan Remedial Investigation, Sigmon 's Septic Site, July 19, 2002.
Black & Veatch, 2002b. Black & Veatch Special Projects Corp. Revised Final Work Plan,
Volume I -Technical Approach, Volume 2 -Confidential Business Information, Sigmon 's Septic
Site, July I 9, 2002.
Black & Veatch, 2004, Black & Veatch Special Projects Corp. Email communication from Nile
Testerman (NCDENR Project Manager) to Chris Allen; dated June 24, 2004.
Black & Veatch, 2006a. Black & Veatch Special Projects Corp, Remedial Investigation Report
Operable Unit 1 for Sigmon's Septic Tank Site -Revision L Prepared for the U.S.
Environmental Protection Agency, Region 4; March 2006.
Black & Veatch, 2006b. Black & Veatch Special Projects Corp. Risk management team
conference call to discuss RGO and clean-up criteria. February 28, 2006.
Black & Veatch, 2006c. Black & Veatch Special Projects Corp. Risk management team
conference call to discuss RGO and clean-up criteria. March 6, 2006.
Burrows, 1993. Letter to Chris DeRoller, NC Division of Environmental Management, from
Steven Burrows, Shield Environmental Associates, dated November 3, 1993. Subject: Septic Pit
Lagoon Sludge Sampling Report.
·. Final Feasibility Study Report -Operable Unit I
EPA Contract No: 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank_ Site
Section 7
. Revision No. 1
June 2006 .' I'. • 1 .r' Page 2 pf6
Connell, 1995. Memorandum to Pat,DeRosa, NC Division of Solid Waste Management, from·.
Karen Corinell, NC Division of Environmental Management, dated December 15, 1995. Subject:
Sigmon Septic:_ Tank Service GroU11dwater. Incident #3422. . , . , , .. ,
Craftsman Book Company, 2005. National CD Estimator -Heavy Construction:' Craftsman ..
Book Company, 6058 Corte de! Cedro, P.O. Box 6500, Carlsbad, CA 92018. ,Downloaded fr~m
. ,. . ( l ·
website· on:. May 14, 2005 . (URL: http://craftsman-book.com/downloads/do.wnload. . . . . . . ' . . . . . ' ., . ', .
php?download id=21). ' -· 1(-''
,(
·.)),elta Re~.earch c;orporation, 2005: Remedial Action Cos_t Estimation (RACER) dec[sion support
software._ This software »'as peveloped by Delta Research Corp~ration (1501 Me1~hants Way,
Niceville, Florida 325_78) . to_ run on a . Microsoft Windows . platf.~rpl-(URL: ·
http://www.deltabtg.com).
DeRoller, 1991. Letter to ·Barry Sigmon, AAA Enterprises, from Chris DeRoller, NC Division
of Environmental Management, dated April 8, 1991. Subject: Groundwater Sampling Results . . ' ',
Groundwater Incident #3422.
DeRosa, 1996. Lett\!r to Cindy Gurley, EPA Region,4, from Pat DeRosa, NC Division of Solid.
. ' . • . • ' • I .
Waste Management, dated December 12, 1996. Subject: CERCLIS Site Addition.
Dickinson, David J. and Scarlette M. Gray, 1986. Method of impregnating wood. United _States·
Patent No. 4,591,515. U.S. Patent and Trademark Office (USPTO); May 27, 1986.
Egerton, Ian K. and Andrew D.J. Broome, 1989. Wood preservation compositions and a process
for their production. United States Patent No. 4,804,494. U.S. Patent and Trademark Office • I • '
(USPTO); February 14, 1989.
Grayson, I 980. Minutes of Meeting in Statesville, North Carolina, by_ Sµsan Grayson, NC
Department of Human Resources, June 20, 1980.
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Final Feasibility Study Report· Operable Unit 1
. EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 7
Revision No. 1
June 2006
Page 3 of6
Hassig, N.L., R.O. Gilbert, L.L. Nuffer, J.E. Wilson, and B.A. Pulsipher, 2005. Visual Sample
Plan -Version 4.0 User's Guide. Report Number PNNL-15247. Prepared for the U.S.
Department of Energy under Contract DE-AC05-76RL0l830. Pacific Northwest National
Laboratory; Richland, Washington 99352. July 2005. (Online URL:
http://dqo.pnl.gov/vsp/pnnl 1524 7.pdf)
Homesley, I 996. Letter to Keith Overcash, NC Division of Environmental Management, from
T.C. Homesley, Jr., Homesley, Jones, Gaines, and Fields, dated February 19, 1996. Subject:
Insolvency of AAA Enterprises.
Lair, 1997. Letter to Jack Butler, NC Division of Solid Waste Management, from Myron Lair,
EPA Region 4, dated April I, 1997. Subject: Sigmon Septic Tank Service Eligibility for
· Removal Action.
Martin, 1992. Internal Memorandum to Keith Masters, NC Waste Management Branch, from
Laurie Martin, dated December 30, 1992. Subject: Site Investigation at Sigmon Septic/AAA
Enterprises.
Moore, 1996a. Memorandum to Pat DeRosa, NC Site Assessment and Removal Branch, from
Douglas Moore, NC Superfund Section, dated December 12, 1996. Subject: Removal
Evaluation.
Moore, 1996b. Memorandum to File, from Douglas Moore, NC Superfund Section, dated
December 17, 1996. Subject: Removal Evaluation and On-Site Reconnaissance.
National Oil and Hazardous Substances Pollution Contingency Plan (NCP). 40 Code of Federal
Regulations (CFR) Part 300.
North Carolina Division of Environmental Management (NCDEM), 1980. Drilling Well
Records and Analytical Sampling Results; September 8, 1980.
North Carolina Department of Environment and Natural Resources (NCDENR), 1998.
Preliminary Assessment Site Investigation. Sigmon's Septic Tank Service, Statesville, Iredell
County, North Carolina; September 1998.
· Final Feasibility Study Report -Operable Unit 1
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RJCO-A44F
Sigmon's Septic Tank Site
North Carolina Department• of Environment .and Natural Resources
Expanded Site Inspection Report, Sigmon 's Septic Tank Service Site,
Statesville, Iredell County, North Carolina; March 31, 2000,
Section}
· Revision No. 1
June 2006
Page4of6
(NCOENR), 2000a.
NCD. 062 555. 792,
North Carolina Department of Environment and Natural Resources (NCDENR), 2006.
Background Soil Study (data tables). Mooresville Regional Office, North Carolina Groundwater
Section. Data provided electronically by Nile Testerman (NCDENR Project, Manager) .on
)anuary 19, 2006. •
North Carolina Department of Natural Resources and Community Development (NCDNRCD),
19~7. Well Construction Records; August 31, 1987.
North Carolina Division of Solid Waste Management (NCDSWM), 1989a. NC Division of
Solid Waste Management, Septage Management Program, Application for Permit to Operate a
Septage Management Firm for AAA Enterprises, May 12, 1989.
North Carolina Division of Solid Waste Management (NCDSWM), 1989b. NC Division of
Solid Waste Management, Septage Management Program, Application for Permit to ·operate a
Septage Management Firm for AAA Enterprises, December 11, 1989.
North Carolina Division of Solid Waste Management (NCDSWM), 1992. NC Division of Solid
Waste Management, Septage Management Program, Application for Permit to Operate a Septage
Management Firm for AAA Enterprises, April 21, 1992.
North Carolina Division of Solid Waste Management (NCDSWM), 1995. NC Division of Solid
Waste Management, Septage Management Program, Authorization to Discharge Septage to a
Wastewater Treatment Facility for Sigmon Environmental, December 15, 1995.
North Carolina Division of Solid Waste Management (NCDSWM), 1997a. Septage
Management Program, Authorization to Discharge Septage to a Wastewater Treatment Facility
for Sigmon Environmental, January 8, 1997.
North Carolina Division of Solid Waste Management (NCDSWM), 1997b. NC Division of
Solid Waste Management, Management Program, Permit to Operate a Septage Management
Firm for Sigmon Environmental, February 20, 1997.
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Final Feasibility Study Report· Operable Unit I
EPA Contract No. 68-W-99-043
Work Assignment No. 340-RICO-A44F
Sigmon's Septic Tank Site
Section 7
Revision No. I
June 2006
Page 5 of6
Readling, I 990. Internal Letter to Keith Masters, NC Hazardous Waste Compliance Unit, from
Scott Readling, dated September 14, 1990. Subject: Site Investigation of AAA Enterprises.
Sigmon, 1980. EPA.Hazardous Waste Notification Form, Part A, Henry Sigmon, Applicant,
November 10, 1980.
Siginon, 1981. Section 3007 RCRA Questionnaire, Followup Information for Part A
Application, Mary Sigmon, Respondent, June 11, I 981.
Sigmon, 1982. Letter to Bill Myer, NC Department of Human Resource, from Mary Sigmon,
AAA Enterprises, dated April 19, 1982. Subject: Reinstatement of AAA Enterprises as a
Transporter.
Sigmon, 1995. Letter to Karen Walker, NC Department of Environment and Natural Resources,
from Barry Sigmon, dated April 26, 1995. Subject: Lagoon Closure Activities Groundwater
Incident #3422.
Steiner, Bill, 2002. Technical memorandum to Beverly Hudson. Review of the Eco Risk
Analysis (Steps 1 and 2) for the Sigmon's Septic Tank Site in Statesville, North Carolina.
U.S. Environmental Protection Agency (EPA), 1987. Interim Guidance on Compliance with
Applicable or Relevant and Appropriate Requirements. Office of Solid Waste and Economy
Response (OSWER). Directive 9234.0-05; July 9, I 987.
U.S. Environmental Protection Agency (EPA), 1988. Guidance for Conducting Remedial
Investigations and Feasibility Studies under CERCLA. Interim Final. EPA-540-G89-004.
October 1988.
U.S. Environmental Protection Agency (EPA), 1989. CERCLA Compliance with Other Laws
Manual: Part II. Clean Air Act and Other Environmental Statutes and State Requirements.
Office of Solid Waste and Economy Response (OSWER). Directive 9234.1-02, August I 989.
· Final Feasibility Study Report -Operable Unit l
EPA Contract No. 68-W-99-043 .
Work Assignment No. 340-RICO-A44F
Sigrnon's Septic Tank Site
Section 7
Revisi,on No. 1
June 2006
.. Page 6 ~f6
U.S. Environmental Protection Agency (EPA), 2000a, Supplemental to RAGS: Region 4 ·
Bulletins· Human_ Health, Risk Assessment Bulletins. : EPA Region · 4, originally published
November: 1995: http://www.epa.gov/region4/waste/oftecser/healtbul.htm
U.S. Environmental Protection· Agency (EPA), 2000b. A Guide to Developing and Documenting
Cost Estimates during the Feasibility Study. EPA 540-R-00-002. July 2000.
,U.S. Environmental Pro.tection Agency (EPA); 2001a. Work Assignment Form for WA No. 040.-. .
RJCO-A44F. Statement of Work (SOW) for the.RI/PS at the. Sigmcin's Septic Tank site in
Statesville, Iredell County, North Carolina; May 7, 2001.
U.S. Environmental Protection Agency (EPA), 2002a. Geophysical Investigation Report for
Sigmon 's Septic Tank Site, Statesville, North Carolina. Performed in conjunction with Blapk and
Veatch Special Projects Corporation in May, 2002.
U.S. Environmental Protection Agency (EPA), 2005. Chromated Copper Arsenate .(CCA).
Interim study on the effectiveness of sealants in reducing the amount of CCA that leaches frqm
the treated wood. May 11, 2005. Online URL: http://www.epa.gov/oppad00l/reregistration/cca .
U.S. Geological Survey (USGS), 1993. 7.5 minute series Topographic Quadrangle Maps of
North Carolina: Troutman, North Carolina 1993.
Zeller, 1981. Letter to Mary Sigmon, AAA Enterprises, from Howard Zeller, dated June 5,
1981. Subject: Section 3007 RCRA Request for Information
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Standaros, Kequirements,
Criteria, or Limitations
FEDERAL
Federal Groundv-.1ater Classification
Safe Drinking Water Act (SDWA)
National Primary Drinking
Water Standards
Clean Water Act
Ambient Water Quality Criteria
Toxic Pollutant Effluent
Standards
National Pollutant Discharge Elimination System (Ni'DbS)
National Pretreatment
Standards
Resource Conservation and Recovery Act (RCRA)
RCRA Groundv.·ater Protection
RCRA Solid Waste Disposal Facility Requirements
Table 2-1
Potential Chemical-Specific ARARs
Sigmon's Septic Tank Site
Statesville, Iredell County, North Carolina
Citation Description Comments
55 Federal Retster Federal classification system to establish The afuifer beneath the site carries a federal classification of (FR) Part 873 groundwater usage categories for aquifers as Class . This classification means that the surficial aquifer is part of a groundwater protection strategy. a sole-source aquifer that is an irreplaceable groundwater resource and warrants a high degree of protection.
40 United Stales Code (USC) f300
40 Code of Federal Established maximum contaminant levels The MCLs for organic and inorganic constituents are relevant Rcfulations (CFR) Part (MCLs) which arc health-based standards for and appropriate to the groundwater contamination in a sole 14 , Subpart B and G public water systems. source aauifer.
33 USC Sect. 1251-1376
40 CFR Part 131 Requires the states to set ambient water quality A WQCs for some inor~nic and o&anic constituents in the criteria ~A WQC) criteria for water quality based groundwater at the site ave been eveloped and may be on use c assifications and the criteria developed relevant and appropriate. under Section 304(a) of the Clean Water Act.
40 CFR Part 129 Establishes effluent standards or prohibitions Would not be applicable because this regulation does not for certain toxic pollutants: aldrin/dieldrin, cover contaminants detected onsite that are site-attributable or DDT, endrin, toxaphcne, benzidine, PCBs. COCs.
40 CFR Parts 122, 125 Detennines maximum concentrations for the Discharge limits would be established for effluent if discharge of ITillutants from any point source discharged to surface water body on site. into waters o the United States.
40 CFR Part 403 Sets standards to control pollutants that pass If an alternative involved discharge to gublicly owned through or interfere \vith treatment processes in treatment works, these standards woul be applicable if publicly owned treatment works or that may discharged on site. contaminate sewage sludge.
40 use 6905, 6912, 6924. 6925
40 CFR Part 264 Provides for groundwater protection standards, The RCRA standards could be relevant and appropriate for general monitoring requirements and technical groundwater at the site if an onsite l~ndfill is constructed. reauirernents.
40 CFR Part 257.3-4 Provides for protection of groundwater at solid May be a~plicable if remedial action includes provisions for waste disoosal facility . an onsitc andfill.
•
Page I of2
-
Standards, Keqmrements,
Criteria, or Limitations
Clean Air Act
National Primal"¥ and
Secondary Ambient Air
Oualitv Standards
National Emissions Standards
for Hazardous Air Pollutants (NESHAPS)
Comprehensive
Environmental Response,
Compensation, and Liability
Act tCERCLA)
STATE
North Carolina Hazardous Waste
Management Rules and Solid
Waste Management Law
ldentlllcatlon ana L1stmg 01
Hazardous Waste
Water Pollution Control
Regulations
North Carolina Dnnkmg Water
Act
North Carolina Water and Air
Resources Act
North Carolina Water Quality
Standards
North Carolina Groundwater
Quality Standard
- ---
•
Table 2-1
Potential Chemical-Specific ARARs
Sigmon's Septic Tank Site
Statesville, lrede ountv, ort aroma IIC N hC r
Citation · Description Comments
42 USC Sect. 7401-7642
40 CFR Part 50 Establishes standards for ambient air quality to May be applicable if contaminants are discharged to the air
protect public health and welfare. durmg a treatment process.
40 CFR Part 61 Provides emissions standards for hazardous air May be relevant or (ipropriate if onsite treatment units with
pollutants for which no ambient air quality emissions arC part o remedial actions. standard exists.
9' l 2 l\o)(2)lB )(IIJ Prov1ues alternative groundwater concentrat1on Tnere are suspected e11scnarges ot groundwater to surtace
limits for groundwater that discharges to a water n"ear the site.
surface water body.
15A NCAC 13A
15A NCAC BA.0006 Deunes t~ose so11u wastes which are subject to Wou1a potentially oe appucame to remeaia1 act10ns 1nvo1vmg state regulation as a hazardous waste. solid waste removal.
Consistent with corresponding federal
standards.
15A NCAC 2B.0100 Estao11snes .acceptable water quality-related Potentially apphcable to remedial act10ns mvo1vmg sun ace
parameters m state surface water. discharge of treated groundwater.
General Statutes 01 NC, Estao11snes criteria tor protection of state public Apphcao1e for the protection 01 annKmg water aqu11er .. Chapter 130A, Article water supplies. State equivalent to Federal
10 SDWA.
General Statutes otNC, Chapter 143, Art1c1e 21
NCAC, Tille 15A,
Chapter 2B
Sunace water quality standards for fresh and
salt water bodies. Apphcame tor tne protection 01 surrace water.
NCAC, Title 15A, Estaousnes groun9water classihcat1ons and App11cao1e. Presents maximum a1_1owao1e concentrat10ns tor Chad:ter 2, Subchapters groundwater quality standards. contaminants including COCs at the Potter's Pits site. 2L. 100, 2L.0200,
?I moo
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:standard, Requirement,
Criteria, or Limitation
FEDERAL
National Historic Preservation
Act
Archaeological and Historic
Preservation
Historic Site, Buildings, and
Antiquities Act
Fish and \Vildlife Coordination
Act
Endangered Species Act
Migratory Bird Treaty Act
Clean Water Act
Dredge or Fill Requirements
(Section 404)
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Citation
16 United States Code
(USC) f 470
40 Code of F cderal
Regulations (CFR) Part
6.301 (b)
36 CFR Part 800
16 USC Sect. 469
40 CFR Seel. 6.30l(c)
16 USC Sect. 461-467
40 CFR Sect. 6.30l(a)
16 use Sect. 661-666
16USC1531
50 CFR Parts 200 and
402
16 use 703 et seq.
Table 2-2
Potential Location-Specific ARARs
Sigmon's Septic Tank Site
Statesville, Iredell County, North Carolina
Description
Requires federal agencies to take into account the effect of any federally-assisted undertaking or licensing on any
district, site, building, structure, or object that is included in, or eligible for inclusion in, the National Register of Historic
Places.
Establishes procedures to provide for preservation of historical and archaeological data which might be destroyed through alteration of terrain as a result of a Federal
construction project or a Federally licensed activity or program.
Requires Federal agencies to consider the existence and location of landmarks on the National Registry of Natural
Landmarks to avoid undesirable impacts on such landmarks.
Requires consultation when Federal department or agency
proposes or authorizes any modification of any stream or other water body and adequate provision for protection of fish and wildlife resources.
Requires action to conserve endangered species within
critical habits upon which endangered species depend, includes consultation with Department oflnterior.
No federal action may jeopardize the habitat of birds with migratory pathways through the area.
33 USCSect.1251 et.~.
40 CFR Parts 230 and Requires permits for discharge of dredged or fill material into
23 I navigable waters.
Page I of3
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Comment
No current district site, b\Jilding, structure, or object listed on or eligible for the National
Register is on or adjacent to the site.
No current historical or archeological data is on or adjacent to the site.
No current National Landmark is on or adjacent to the site.
Unlikely that an alternative would cause damage
or loss of wildlife by modifying a stream or body
of water.
No threatened or endangered species or critical
habitats are identified at the site.
Unlikely that an alternative would effect any migratory nathways.
Unlikely that an alternative would require
discharge of dredge or fill material into navigable . ., .
Standard, Requirement,
Criteria, or Limitation
Rivers and Harborn Act of
1899
Section IO Permit
Executive Order on Flood
Plail1 Management
Executive Order on
Protection of Wetlands
Wilderness Act
National Wildlife Refuge
System
Scenic River Act
Coastal Zone Management Act
STATE
North Carol ma Solid and
Hazardous Waste Management
Act
Sttmg Cntena for
Hazardous Waste
Treatment and Disposal
Facilities
Dam Satcty and W~tcrway
Mana2:emcnt Act
-- --
Citation
33 USC Sect. 403
33 CFR Parts 320-330
Executive Order No.
11,988
Executive Order No.
11,990 40 CFR 6.302(a)
and Appendix A
16USC 1311
50 CFR 35.1
16 USC 668
50 CFR 27
16 use 1211
40 CFR 6.302(e)
16USC 1451
Table 2-2
Potential Location-Specific ARARs
Sigmon's Septic Tank Site
Statesville, Iredell County, North Carolina
Description
Requires permit for structures of work in or affecting
navigable waters.
Requires Federal agencies to evaluate the potential effects of
actions they may take in a flood plain to avoid, to the extent
possible, the adverse impacts associated with direct and
indirect develooment of a flood plain.
Reqmres Federal agencies to avo1C1, to the extent poss101e,
the adverse impacts associated with the destruction or loss of
wetlands and to avoid support of new construction in
wetlands ifa practicable alternative exists.
Administer facility owned wilderness area to leave it
unimpacted.
Restricts activities within a National Wildlife Refuge.
Prohibits adverse effects on scenic river.
Conduct activities in accordance with State approved
manageme.nt program.
General Statutes, Chapter 130A, Article 9
Estaousnes state s1tmg cntena ror new nazaraous waste
15A NCAC 13A.0009 treatment and disposal facilities.
15A NCAC Estabhshes state cntena tor protection ot wetlands.
Page 2 of3
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Comment
It is unlikely that an alternative would effect a
navigable waterway.
Site activities will be located outside the 500-year
flood plain.
Un,111..ely an alternative woulel nave a negative
impact on area wetlands.
No wilderness areas exist on site or adjacent to the
site.
No wildlife refuge areas exist on site·or adjacent
to the site.
No scenic river is in the area of the site.
The site is not located near the coastal zone.
Potentrnuy app11cao1e II a treatment or msposa1
facility is set up onsite for hazardous waste.
No· wet1anos nave oeen tuentmed on the S:sTS.
-----
-----..
Standard, Requirement,
Criteria, or Limitation Citation
Watershed Management Act 15A NCAC
Game and Wildlife Code 15A NCAC
-----
Table 2-2
Potential Location-Specific ARARs
Sigmon's Septic Tank Site
Statesville, Iredell County, North Carolina
Description
Estao11shes state criteria tor nrotection 01 floodplains.
Allows the State Game Comm1ss1on to protect, propagate,
manage, and preserve game fur-bearing animals and birds through management of lands for public hunting.
Page 3 of3
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Comment
The site 1s not locatcct ma tloodplam.
The sue 1s private property and not designated for
hunting activities.
------------- ---- -
Standarel, Requirement,
Criteria, or Limitation
FEDERAL
Solid \Vaste Disoosal Act
Criteria for Classification of
Solid \Vaste Disposal Facilities
and Practices
Hazardous Waste Management
Systems General
Identification and Listing of
Hazardous Wastes
Standards Applicable to
Generators ofHaz.ardous
Waste
Standards Applicable to
Transporters of Hazardous
Waste
Standards for Owners and
Operators of Hazardous Waste
Treatment, Storage, and
Disoosal.Facilities
Interim Standards for Owners
and Operators of Hazardous
Waste Treatment, Storage, and
Disposal Facilities
Standards for Management of
Specific Hazardous Wastes
and Specific Types of
Ha7..ardous Waste Management
Facilities
Citation
Table 2-3
Potential Action-Specific ARARs
Sigmon's Septic Tank Site
Statesville, Iredell County, North Carolina
Description
40 United States Code (USC) f 6901-6987
40 Code of Federal Establishes criteria for use in detennining which solid Regulations (CFR) waste disposal facilities and practices pose a reasonable Part 257 probability of adverse effects on health, and thereby constitute prohibited open dumps.
40 CFR Part 260 Establishes procedure and criteria for modification or revocation of any provision in 40 CFR Parts 260-265.
40 CFR Part 261 Defines those solid wastes which are subject to regulations
as hazardous wastes under 40 CFR Parts 262-265 and Parts
124,270, and 271, -
40 CFR Part 262 Establishes standards for generators of hazardous waste.
40 CFR Part 263 Establishes standards which apply to persons transporting
hazardous waste within the U.S. if the transportation
requires a manifest under 40 CFR Part-262.
40 CFR Part 264 Establishes minimum national standards which define the
acceptable management of hazardous waste for owners and operators of facilities which treat, store, or dispose of
hazardous waste.
40 CFR Part 265 Establishes minimum national standards which define the
acceptable management of hazardous waste during the period of interim status and until certification of final
closure or if the facility is subject to post-closure
requirements, until post-closure responsibilities are fulfilled,
40 CF R Part 266 Establishes requirements which apply to recyclable
materials.
Page I of5
Comments
If an alternative involved onsitc land disposal of solid
waste, this part would be applicable.
May be applicable if a substance from the site was to
be excluded from the list of hazardous wastes.
Would be applicable in identifying if a substance at
the site should be· defined as a hazardous waste.
Would require handling as a ha:t..ardous waste.
If an alternative involved onsite diSposal or treatment
of hazardous wastes, these standards would be
annlicable.
If an alternative involved onsite transportation of
haz.ardous wastes, these standards apply.
May be applicable or relevant and appropriate if
hazardous waste will be disposed of onsite.
May be applicable or relevant and appropriate if hazardous waste will be disposed of onsite.
No substances arc anticipated to be present at the site in quantities to warrant recycling.
I!!!!!!!!
Standard, Requirement,
Criteria, or Limitation
Interim Standards for Owners
and Operators of New
Hazardo~s Waste Land
Disposal Facilities
Land Disposal
Hazardous Waste Permit
Program
Underground Storage Tanks
Occupat1onal Satety and Health
Act
Inspections, Citations, and
Proposed Penalties
Rccordmg and Reporting·
Occupational Injuries and
Illnesses
General Industry Standards
Occupational Satety and
Health Standards for the
Construction Industry
Safe Drinkini! Water Act
- - - -
Citation
40 CFR Part 267
40 CFR Part 268
40 CFR Part 270
40 CFR Part 280
Table 2-3
Potential Action-Specific ARARs
Sigmon's Septic Tank Site
Statesville, Iredell County, North Carolina
Description
Establishes minimum national standards which define the
acceptable management of hazardous waste for new land
disposal facilities.
Establishes a timetable for restriction of burial of wastes
and other hazardous materials.
Establishes provisions covering basic EPA permitting
requirements.
Establishes regulations related to underground storage
tanks.
29 USC Sect. 651-678
Regulates worker health and safety with regards to onsite
29 CFR Part 1903 remedial activities. Authorizes the Department of Labor to
conduct inspections and to issue citations and-proposed -penalties for alleged violations.
Regulates worker healtn and satety w1tn regard to onslte
29 CFR Part I 904 remedial activities. Provides for record keeping and
reporting by employers.
Regulates worker health and satety and regards to onsite
remedial activities. Establishes generic specifications for
29 CFR Part 19 IO using tools maintaining industrial structures, installing
work place safety equipment, providing medical attention,
and other general health and safety practices.
29 CFR Part 1926
Regulates worker health and satety w1tn regaras to ons1te
remedial activity. Establishes safety and health standards
for the construction industry.
42 USC Sect. 300/f)
Page 2 of5
Comments
May be applicable or relevant and appropriate if
hazardous waste will be disposed of onsite.
May be applicable or relevant and appropriate if
hazardous waste will be disposed of onsite.
A permit is not required for onsite CERCLA response
actions. Substantive requirements are addressed in 40
CFR Part 264.
Would be applicable if an alternative would involve
use of underground storage tanks onsite.
Under 40 CFR Section 300.38, requirements of the
Act apply to all response activities upder the NCP.
Under 40 CFR Section 300.38, requirements of the
Act apply to all response activities under the NCP.
Under 40 CFR Section 300.38, requirements of the
Act apply to all response activities under the NCP.
Unaer 40 CFR Section 3u0.38, requirements 01 tne
Act apply to all response activities under the NCP.
- -- --- - - -----
-------- ----·----- -
Standard, Kequirement,
Criteria, or Limitation
Standards for Owners and
Operators of Public Water
Suoply System
Underground Injection Control
(UIC) Regulations
Clean \Valt:r Act
National Pollutant Discharge
Elimination System (NPDES)
Ambient Water Quality
Criteria
National Pretreatment
Standards
Toxic Pollutant Effluent
Standards
Citation
40 CFR 141
40 CFR Parts 144-
147
Table 2-3
Potential Action-Specific ARARs
Sigmon's Septic Tank Site
Statesville, Iredell County, North Carolina
Description
Provides treatment (water quality) requirements for public
water supply systems.
Provides for protection of underground sources of drinking water.
33 use Sect. 125I-1376
40 CFR Parts 122 and Requires pcnnits for the discharge of pollutants from any 125 point source into waters of the United States.
40 CFR Part 13 I Requires the states to set A WQC criteria for water quality Quality Criteria for
Water, I 976, I 980, based on use classifications and the criteria developed
1986 under Section 304(a) of the Clean Water Act.
Sets standards to control pollutants v-:hich pass through or 40 CF R Part 403 interfere with treatment processes in publicly owned treatment works or which may contaminate sewage sludge.
Establishes effiuent standards or prohibitions for certain 40CFRPart 129 toxic pollutants: aldrin/dieldrin, DDT, endrin, toxaphene,
benzidine, PCBs.
Page 3 of5
Comments
MCLs may be relevant and appropriate to the
establishment of cleanup goals for groundwater
contamination.
If an alternative involved onsite underground
injection, this part \\'Ould be annlicable.
A permit is not required for onsite CERCLA response
actions, but the substantive requirements would apply if an alternative involved discharge into a creek or
other surface water on site. A pennit would be required if the discharge is to a creek or other surface
water off site.
A WQCs for some inorganic and organic constituents
in the groundwater at the site have been developed
and may be relevant and appropriate.
If an alternative involved discharge to a publicly
owned treatment works, these standards \\'ould be annlicable.
These contaminants are not site attributable potential contaminants of concern at the site. However, if
these contaminants are detected, these regulations
would be ann!icablc.
-
-
Standard, Reqmrement,
Criteria, or Limitation
Clean Air Act
National Ambient Air Quality
Standards
Noise Control Act of 1972
Hazardous Materials
Transnonation Act
Hazardous Materials
Transportation Regulations
STATE
Nortn Carol ma So11u and
Hazardous Waste Management
Act
Solid Waste Management
Rules
Hazardous Waste Management
Water Pollution Control
Regulations
Citation
Table 2-3
Potential Action-Specific ARARs
Sigmon's Septic Tank Site
Statesville, Iredell County, North Carolina
Description
42 USC Sect. 7401-7642
40 CFR 50.1-.17 .. 50-
.54; .150-.154 .480-Treatment technology standard for emissions to air from .489; 40 CFR 53.1-
.33; 40 CFR 61.01-incinerators, surface impoundments, waste piles, landfills,
. 18 .50-.112, .240-and fugitive emissions.
.247
42 USC Sect. 4901 et Federal activities must not result in noise that will
seq. jeopardize the health or welfare of public.
.
49 USC Sect. 1801-1813
49 CFR Parts I 07,
171-177 Regulates transportation of hazardous materials.
General Statutes, Chapter 130A, Article 9
15A NCAC 13B Establishes state-level comprehensive residual waste
management system.
15A NCAV 13A Establishes state_-level version of comprehensive waste
management system.
NLAC T1t1e 15, Requires penmt tor discharge ol ettluent trom pomt
Chapter 2, Subchapter sources into surface waters. State-level version of federal
2H NPDES oroizram.
Page 4 of5
- - --- - --- -
Comments
If an alternative involved emissions governed by
these standards then the requirements would be
applicable .
If activities, such as drilling, etc., were to take place
too close to a public access point, this may be
applicable .
If an alternative involved transportation of hazardous
materials, these requirements would apply. Does not
apoly to remediation onsite.
Potentially applicable to rcmectml act10ns mvolvmg
removal of wastes that qualify as residual waste.
Potentially apolicable to drill cuttings.
Potcnt1ally applicable to remedial actions mvolvmg
removal of wastes that qualify as hazardous wastes.
Potentially applicable to drill cuttings.
Potentially applicable to remedial actions involving
point source discharges to surface \Vaters.
- - - - -
---·-
~tandard, Kequ1rement.
Criteria, or Limitation
Wastewater Treatment
RcquircrncnL'>
Erosion Control
North Carol ma Water and Air
Resources Act
Standards for Contaminants
Standards for Sources of
voes
North Carolina Groundwater
Quality Standards
--------- -----
Citation
NCAC Title 15,
Chapter 2, Subchapter
2H.01
15A NCAC, Chapter
4. Subchaoter 4B
Table 2-3
Potential Action-Specific ARARs
Sigmon's Septic Tank Site Statesville, Iredell County, North Carolina
Description
Establishes basic ,.,,astcwater treatment requirements for effluent discharge.
.
Estaoushes erosion and sed1mentat1on control measures tor earth-moving activities
General Statutes, Chapter 143, Article 21
NCAC Title 15A, Establishes state source-specific emissions limitations for Chapter 2, Subchapter
2D particulate matter, sulfur compounds, odor, and opacity.
NCAC Title 15A, Establishes state standards for storage tanks containing Chapter 2, Subchapter voes. 2D
NCAC Title I 5A,
Chapter 2, Establishes a series of classifications and water quality Subchapters 2L.0 IO0, n coon 01 0100
standards applicable to groundwater of the state.
Page 5 of5
Comments
Potentially applicable to remedial actions involving
point source discharges to surface waters.
Potentially applicable for earth moving activities.
Potentially applicable for earth moving activities.
Potentially applicable to remedial actions utilizing storage tanks for wastes containg VOCs.
Potentially applicable for protection of groundwater..
-
-------- --------
Is the Contaminant a COC in this
Contaminant medium?
GW ss SB
I Aluminum Yes -I No
i
Arsenic Yes No I No
Barium Yes No f No
--j
Chromium No -I -
Iron Yes --~anese Yes No No
Mercury ___ Yes No ' No
I
Toalli~ No -No
I
Vanadium Yes Yes I -I I Zinc Yes No I No
I I
Table 2--4
Table of Applicable RGOs and Cleanup Criteria Selection
Sigmon's Septic Tank Site
Statesville, Iredell County, North Carolina
Cao Cootamiaa~ NC (3) Most Sensitive Receptor Most Sensitive Receptor Potentially 2006 NC (2) Leaehing EPA DAF3 (3) and RGO in Surface SOil and RGO in Surface Soil Leacti to GW? (1) SRG (mg/kg) (m909) Leadl (mg/kg) Receptor RGO Receptor RGO
!
Yes NE NE 72010(4) Child Resident 76865 None NA
Yes NE NE 4.0 None NA None NA
Yes NA 848 241.8 None NA None NA
Construction No 44 (see note) NA NA Child Resident 155 Worker 858
Construction Yes NE NE NE Child Resident 22730 Worker 91729
Yes NA 65.2 NE None NA None NA --
Yes NA O.D15 NE None NA None NA
No 1.04 NE NE Child Resident 6 None NA
Construction Yes 15.6 NE 900 Child 73 Worker 308
Yes NA NE 1817.8 None NA None NA
Governing Clean-up Maximum
Criterion for Soil (5) Concentration
ss SB ss -I
72010 72010 -~
4.0 4.o 4.2
242 242 560
155 858 8Q
(6)
22730 91729 -65.2 65.2 770
0.015 0.D15 0.75
6 6 ...
73 308 c;-g;{&l~:,
1817.8 1817.8 .,.
!
Note: The human health risk assessment was conducted in 2005, prior to 2006 North Carolina Soil Remediation Goals becoming available. \f,Jhen 2005 and 2006 values differed, the 2006 value was use. NE. Not Established
NA -Not Applicable
Note: Strikeouts indicate that the particular CCC/medium combination is eliminated from the need tor remedial action. Shaded cells correspond to CCC/medium combinations that are retained for remedial action. (1) tt a groundwater COC is not identified as a soil COG, then the soil leachabllity criteria apply. Conversely, if a soil COC is not also a groundwater COG, then leachabfitty criteria do not apply. (2) NA in this column means that a 2006 NC SRG exists; however, the contaminant is not a COG for soil exposure. Leachability criteria would apply, but not the SRG. (3) N/\ in this column means that available leachability criteria values do not apply here. The contaminant is a COG in soi! but not in groundwater, so leaching is not an issue. (4) Leachability standard was cala.Jlated based on a RGO of 16 mg/L (for the child resident receptor).
--
Maximum
Coocentration
SB
~~
7.6
--860 ___
,.
"""""
450
1.6~
._.
""'
2100
(5) Soil SRG and leaching standards are compared to numbers generated in the human health risk assessment, as applicable. Selection of final deanup criteria occurred during the risk management conference call of Marcil 6, 2006. (6) The maximum concentration of iron in surface soil exceeded the governing deanup criterion; however, it exceeded that criterion in only one sample. Therefore, ii was deleted as a COG. (7) The background concentraUons used are based on "similar soil" from the local NC oounties.
AU units are in parts per million (mg/kg)
Page 1 of2
-
CDC Media
Aluminum lsurface Soil
Aluminum Subsurface Soil
Arsenic Surface Soil
Arsenic Subsurface Soil
Barium Surface Soil
Barium Subsurface Soil
Chromium Surface Soil
Chromium Subsurface Soil
Iron Surface Soil
Iron Subsurface Soil
Manganese Surface Soil
Manganese Subsurface Soil
Mercury Surface Soil
Mercury Subsurface Soil
Thamum Surface Soil
ThaUium Subsurface Soil
Vanadium Subsurface Soil
Zinc Surface Soil
Zinc Subsurface Soil
---
I
Table 2-4
Table of Applicable RGOs and Cleanup Criteria Selection
Sigmon's Septic Tank Site
Statesville, Iredell County, North Carolin~
Rationale for Elimination as COC I The maximum observed concentration in surface soil was less than the risk-based RGO
Onlv one subsurface soil samole exceeded the orotection of groundwater leachabiliN' standard
Very few surface soil samples exceeded the protection of groundwater leachability standard and aluminum waj not found in the grouiidwater above it's MCL Very few subsurface soil samt les exceeded the protection of groundwater leachability standard and aluminum was not found in the groundwater above it's MCL Although some surface soil samoles exceeded the protection of groundwater leachabilitv standard, barium was not found in oroundwater above it's MCL Although some subsurface soil samples exceeded the protection of groundwater leachabilily standard, barium was not found in groundwater above it's MCL Although some surfaca soil samples exceeded the protection of groundwaterleachabili~ standard, Chromium was not found in groundwater above it's MCL The maximum observed concentration in subsurface soil was less than the risk-based RGO
Only one surface soil sample exceeded the risk-based RGO
The maximum observed concentration in subsurface soil was less than the risk-based RGO
Although some surface soil samples exceeded the protection of groundwater leachabUily standard and it's respective MCL, EPA and State of North Carolina have agreed to monitor the concentrations of manganese in groundwater.
Although some subsurface soil samples exceeded the protection of groundwater reachability standard and it's respective MCL, EPA and State of North Caro!lna have aareed lo monitor the concentrations of manganese in groundwater.
Although some surtac.e soil samples exceeded the protection of groundwater leachabilily standard, merrury was only found in one sample above it's respective MCL. ~
Although some subsurface soil samples exceeded the protection of groundwater leachabilily standard, men::ury was only found in one sample above it's respective MCL.
The maximum observed concentration in surface soil was less than the risk-based RGO
The maximum observed concentration in surface soil was less than the risk-based RGO
The maximum observed concentration in surface soil was less than the risk-based RGO
The maximum observed concentration was less than the protection of groundwater leachabHity standard
Atthouqh some subsurface soil samo!es e)(ceeded the protection of Qroundwater leachabilitv standard, zinc was not found in Qroundwater above it's MCL
Page 1 of 2
---------------
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D
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General Response Action Remedial Technology Process Option
Not Applicable ~=:::N:o:A:c:t::io:n==='.HL ____ __:_N::o:::n:::• ____ __JH
Institutional Controls Access and Use Restrictions Land Use Restrictions
Deed/Zoning Restrictions
Fencing
Environmental Monitoring Air, Soil, and/or Groundwater
Containme0s,_t __ .J Caps Atl Processes
~---R_e_m_o_v_a_l __ ~H'------=E::.xca=v::a::ti:::o::.n ____ .JHL ___ _;A..:lc.l :..P::.ro::c::•:::s:::s•::;s:.._ ___ ...J
Treatment In Situ . ----------------------------------..
Offsite
Soil Flushing
Solidification/Stabilization/
Composting/Fixation
Vitrification
---Stea'; Exiracti;;' --7 -------------
RCRA Hazardous Waste
Treatment Facility
: ~ ~ Process option eliminated from further consideration
Section 3
Identification, Screening, and Evaluation of Technologies and Process Options
Description
Site is left in its existing state.
Land use restrictions recorded in property deeds to prohibit activities that might disturb contaminated soiL
Deeds for property in the area of contamination would include restrictions on wells and activities that might disturb
contaminated soil.
Security fence insta1led around contaminated area to limit access.
Site conditions and contaminant levels in these media 1NOuld be monitored during and after implementation of remedial action.
Placement of a cap of low permeability material over the area occupied by the contaminated soil to minimize the infiltration
of surface water. Cap types include native soil, clay, asphalt, concrete, synthetic membrane, and RCRA multilayer.
Use of grouts, low permeability slurry, or liners placed beneath wastes to limit leaching of contaminants (horizontal barrier)
or perpendicular to wastes to form an impermeable barrier (vertical barrier).
Use of mechanical excavating equipment to remove and load contaminated soil for transport.
The activity of naturally occurring microbes is stimulated by circulating water-based solutions through contaminated soil to
enhance in situ biological degradation of organic contaminants. Nutrients, oxygen, or other amendments may be used to
enhance biodegradation and contaminant desorption from subsurface materials.
Oxygen is delivered to contaminated unsaturated soil by forced air movement (either extraction or injection of air) to
increase oxygen concentrations and stimulate biodegradation. The system also may include the injection of contaminated
gases, using the soil system for remediation.
Contaminants are made unavailable to biological organisms after uptake through tree (e.g., poplar) roots.
Water, or water containing an additive to enhance contaminant solubility, is applied to the soil or injected into the
groundwater lo raise the water table into the contaminated soil zone. Contaminants are leached into the groundwater,
which is then extracted and captured/treated/removed.
Vacuum is applied through extraction wells to create a pressure gradient that induces gas-phase volatiles to diffuse through
soil to extraction wells. The process includes a system for handling offgases. This technology is kno......., as in situ soil
venting, in situ volatilization, enhanced volatilization, or soil vacuum extraction.
Contaminants are physically bound or enclosed within a stabilized mass (solidification), or chemical reactions are induced
bet'-Neen the stabilizing agent and contaminants to reduce their mobility (stabilization).
Electrodes for applying electricity, or joule heating, are used to melt contaminated soil, producing a glass and crystalline
structure with very low leaching characteristics.
Steam/hot air injection is used to increase the mobility of VOCs and facilitate extraction. The process includes a system for
handling off-gases.
Excavated soil is transported to ;;i RCRA Subtitle C facility for treatment and subsequent landfill disposal.
Screening Comment
Required for consideration by the NCP.
Retained for further evaluation.
Retained for further evaluation.
Retained for further evaluation.
Retained for further evaluation.
Retained for further evaluation.
Rejected. A large percentage of the total volume of contaminated soil
is limited to the surface. It 'NOUld be more effective and practical to
remediate the material in place or remove it for treatmenUdisposal as
opposed to creating barriers around and/or under the areas. It 'NOUld
be difficult to predict the reliability of a horizontal barrier over such a
large area.
Retained for further evaluation.
Rejected. Technology is ineffective for the site's inorganic
contaminants.
Rejected. Technology is ineffective for the site's inorganic
contaminants.
Rejected. Unkno......., effectiveness for type and concentrations of
contaminants present at the site.
Retained for further evaluation.
Rejected. Technology is ineffective for the site's inorganic
contaminants.
Retained for further evaluation.
Retained for further evaluation.
Rejected. Technology is ineffective for the site's inorganic
contaminants.
Retained for further evaluation.
Table 3-1
Initial Screening of Technologies and Process Options for Soils/Sediments
Sigmons Septic Tanks Site
Statesville, North Carolina
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General Response Action Remedial Technology
Thermal
Physical/Chemical
Disposal Onsite
Off site
Process Option
--Incineration -I .. ___________ _
Pyrometallurgical Processing
Vitrification
Soil Washing
Solidification/Stabilization/
Composting/Fixation
r Ch";;i-caT R8d';ctloni'o7ici:'ti'on 7 1,, ___________ .....
Onsite RCRA Landfill
Backfill Treated Material
RCRA Landfill
(Hazardous or Nonhazardous)
:-=. ~ Process option eliminated from further consideration
Section 3
Identification, Screening, and Evaluation of Technologies and Process Options
Description
High temperatures, 1,600 to 2,200 degrees F, are used to volatilize and combust (in the presence of oxygen) organic
contaminants in hazardous waste. Processes include liquid injection, rotary-kiln, fluidized-and circulatory-bed, and infrared.
Wastes are heated at lowC..r medium temperatures to volatilize water and organic contaminants. A carrier gas or vacuum
system transports volatilized water and organics to the gas treatment system.
Pyrometatlurgy encompasses elevated temperature techniques for extraction and processing of metats, including roasting,
retorting and smelting for use or disposal.
Contaminated soil is melted at high temperatures to form glass and crystalline characteristics.
Excavated soil is mixed with soil amendments and placed in aboveground enclosures that have leachate collection systems
and some form of aeration. Processes include prepared treatment beds, biotreatment cells, and soil piles. Moisture, heat,
nutrients, oxygen, and pH may be controlled to enhance biodegradation.
An aqueous slurry is created by combining soil with water and other additives. The slurry is mixed to keep solids
suspended and microorganisms in contact with the soil contaminants. Nutrients, oxygen, and pH in the bioreactor may be
controlled to enhance biodegradation. Upon completion of the process, the slurry is dewatered and the treated soil is
disposed.
Contaminants sorbed onto the soil particles are separated from soil in an aqueous-based system. The wash water may be
augmented with a basic leaching agent, surfactant, pH adjustment, or chelating agent to help remove organics and heavy
metals.
Contaminants are physically bound or enclosed within a stabilized mass (solidification), or chemical reactions /interactions
are induced to help remove organics and heavy metals or otherwise prevent solubilization of contaminants.
An alkaline polyethylene glycolate (APEG) reagent is used to dehalogenate halogenated aromatic compounds in a batch
reactor. Potassium polyethylene glycolate (KPEG) is the most common APEG reagent. Contaminated soil and the reagent
are mixed and heated in a treatment vessel. In the APEG process, the reaction causes the polyethylene glycol to replace
halogen molecules and render the compound nonhazardous. The reaction between chlorinated organics and KPEG causes
replacement of a chlorine molecule and results in a reduction in toxicity.
Waste and solvent are mixed in an extractor, dissolving the organic contaminant into the solvent. The extracted organics
and solvent are then placed in a separator, where the contaminants and solvent are separated for treatment and further
use.
Reduction/oxidation chemically converts hazardous contaminants to nonhazardous or less toxic compounds that are more
stable, less mobile, and/or inert. The reducing/oxidizing agents most commonly used are ozone, hydrogen peroxide,
hypochlorites, and chlorine. Chemical oxidation is often enhanced using ultraviolet (UV) irradiation or chemical catalysts.
Excavated soil is permanently disposed of in a centrally located RCRA landfill.
Treated soil is placed in a central location or back into excavated areas.
Excavated soil (treated or untreated) is disposed of in a RCRA Subtitle C or D landfill depending on TCLP results.
Screening Comment
Rejected. Technology is ineffective for the site's inorganic
contalTiinants.
Reject~d. Technology is ineffective for the site's inorganic
contaminants.
Retained for further consideration.
Retain~d for further consideration.
Reject~d. Technology is ineffective for the site's inorganic
contaminants.
Rejected. Technology is ineffective for the site's inorganic
contaminants.
Retained for further consideration.
Retained for further consideration.
Rejected. Technology is ineffective for the site's contaminants.
Rejected. Technology is ineffective for the site's inorganic
contaminants.
Rejected. Technology is ineffective for the site's inorganic
contaminants.
Retained for further evaluation.
Retained for further evaluation.
Retained for further evaluation.
Table 3-1 (continued)
Initial Screening of Technologies and Process Options for Soils/Sediments
Sigmons Septic Tank Site
Statesville, North Carolina
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General Response Action Remedial Technology Process Option
No Action H None H~==::::N::o::t':Ap:':pl::,:a":b:::le::::::==:::!
I Institutional Controls L--...1 Access and Use Restrictions Land Use Restrictions I
r Deed/Zoning Restrictions I
' Fencing I
'-I Environmental Monitorinn 7 r Air, sou, and/or Groundwater I
~--~R=e0m000,=•cl ___ JH'---~E0,0c=•=•=•=tio="=----'Hc ____ AcccllcPcroc=e=s=s=e=s~ __ _,
r·----, i_ __ _j
Treatment : ____ In Situ ___ 1 r-------------, __ Soil FlushJmL __ ....1
SollldificationfStablllzatlon I L _ Composting/Fixation _ _J
_ _ _ Vitrification ___ 7
Offslte L____r RCRA Hazardous Waste 7 • • I Treatment Facllltv I ________ ;,:;ii __ _
1 _ _ _ Thennal __ -rl'.!.omel>llu'j!cal Pmcess!!!liJ
Le __ Vllriflcalloa ___ J
Process option eliminated from further consideration
Effectiveness
Does not achieve any measure of remediation or meet RAOs.
Does not achieve any measure of remediation or meet RAOs. Effectiveness
depends on enforcement of restrictions. Used in conjunction with other
Does not achieve any measure of remediation or meet RAOs. Effectiveness
depends on future land use. Used in conjunction with other technologies.
Does not achieve any measures of remediation or meet RAOs. Provides
minimal protection to receptors. Site is already fenced. Used in conjunction
with other technologies.
Does not achieve any measure of remediation or meet RAOs. Useful for
tracking contaminant migration and/or effectiveness of remedial actions.
Used in conjunction with other technologies.
Capping would effectively minimize the potential for drect contact with
contaminated material and limit leaching of the site contaminants.
Proven, reliable technology. Would effectively reduce the potential threat to
human health. Short-term effects include noise and fugitive dust emissions
Would be used in conjunction with an ex situ treatment technology.
Should be effective for the removal of most inorganics however, site geology
including impermeable layers is not conducive to this technology. Will result in
a concentration of contaminants. Successful treatment of metal-loaded
leachant is required for the successful cleaning of soil. Soil washing has been
applied at several Superfund sites.
The spatial distribution of inorganic contamination both onsite and offsite
areas will make this insitu technology impractical. Solidification/stabilization
has been proven effective for reducing the mobility of metals in contaminated
soils. Would not reduce the volume or toxicity of contamiants, only their
mobility by binding and encapsulating them.
Vitrification may or may not be applicable for the site contaminants depending
on the level of difficulty encountered in retaining metals in the melt, and
controlling and treating any volatile emissions that may occur.
Would meet the RAOs by removing contaminated so~ and sediment from the
site. However, offsite treatment may not be the most cost effective solution
since onsite treatment is a feasible alternative.
Pyrometallurgical processing usually is preceded by physical treatment to
produce a uniform feed material and upgrade the metal content. In order for
this technology to be technically feasibly, it must be possible to generate a
concentrate from the contaminated soil that will be acceptable to the
processor.
Vitrification may or may not be applicable for the site contaminants depending
on the level of difficulty encountered in retaining metals in the melt, and
controlling and treating any volatile emissions that may occur.
Section 3
Identification, Screening, and Evaluation of Technologies and Process Options
Implementability
Readily implementable since no action is taken.
Readily implementable.
Readily implementable.
Readily implementable. Requires long-term maintenance. Equipment,
seNices, and personnel readily available.
Readily implementable. No construction or operation is necessary.
Equipment, seNices, and personnel are already available and procedures
are in place.
Implementable. Conventional technology. Equipment, personnel, and
services readily available. Requires long-term maintenance. Requires
restrictions on future land use.
Easily implementable. Equipment, personnel, and services readily available
May be implementable at the SSTS; however, its implementability may be
problematic for several reasons. First, most extraction solutions are
effective only for a narrow range of metals and matrix combinations;
therefore, a single target metal would be preferable to multiple metals. Also,
the method has been used for Cr, Hg, and Pb treatment but not for As
which is also present at the site. The site geology will also make the
implementation of this technology diff1Cult.
Requires relatively simple technologies; easy to construct and operate. May
result in a significant increase in volume.
In situ vitrification faces implementation problems where soils contain >25%
moisture content (causing excessive fuel consumption), metals
concentration in soils exceed their solubility in glass, or As is present in
waste (may require pretreatment to produce less volatile forms).
Easily implementable. Equipment, personnel, and services readily
available
Few pyrometallurgical systems are currently available in mobile or
transportable conf19urations. Offsite treatment must comply with EPA's
offsite treatment policies and procedures. Unless a very concentrated feed
steam can be generated, there will be a charge, in addition to transportation,
for processing the concentrate.
Ex situ vitrification faces implementation problems where waste contains
>25% moisture content (causing excessive fuel consumption), metals
concentration in soils exceed their solubility in glass, or As is present in
waste (may require pretreatment to produce less volatile fom,s).
Cost
Negligible
Minimal
Minimal
Low capital; low O&M
Low capital:
negligible O&M
Moderate to high
capital; moderate
Moderate capital;
negligible O&M
Moderate to high
capital; negligible
O&M
Moderate to high
capital; moderate
High capital; high
Moderate to high
capttal, negligible
O&M
High capital; high
High to very high
Table 3-2
Evaluation of Process Options for Contaminated Soils and Sediments
Sigmons Septic Tank Site
Statesville, North Carolina
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I General Response Action Remedial Technology
I Ph icaVChemical
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I Disposal Onsite
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I Offsite
I [::] Process option eliminated from further consideration
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Process Option
___ SoilWash}ns_ __ 7
Solid ification/Stabi!ization/
Composting/Fixation
_ Onslte RCRA Landfill _ J
Backfill Treated Material
RCRA Landfill (Hazardous or
Effectiveness
Should be effective for the removal of most metals. Will result in a
concentration of contaminants. Successful treatment of metal-loaded
leachant is required for the successful cleaning of soil. Soil washing has been
applied or selected at several Superfund sites.
Solidification/Stabilization has been proven effective for reducing the mobility
of metals in contaminated soils and sediments. Would not reduce the volume
or toxicity of contaminants, only their mobility by binding and encapsulating
them. Use of biosolids, and biosolid composting to restore metals
contaminated land is an emerging technology with limited tun scale
application.
Proven, effective method for disposing of contaminated soil. Material from
offsite would be excavated and consolidated onsite. Would minimize the
potential for direct contact with contaminated material Does not treat
contamination.
Effective means for placement of treated material back onsite. Note that
Land Disposal Restrictions (LDRs) must be met prior to placement.
Effective method of disposing of contaminated soil and sediment. Must meet
the waste accpetance criteria of the landfill.
Section 3
Identification. Screening, and Evaluation of Technologies and Process Options
Implementability
May be implementable at the RSDS; however, its implementability may be
problematic for several reasons. First, most extraction solutions are
effective only for a narrow range of metals and matrix combinations;
therefore, a single target metal would be preferable to multiple metals. Also,
the method has been used for Cr, Hg, and Pb treatment but not for As
which is also present at the site.
Requires relatively simple technologies; easy to construct and operate. May
result in a significant increase in volume.
Would require compliance with state landfill siting requirements, as well as
other landfill regulations. Requires permanent restrictions on future land
use and long-term maintenance. Because of the large volume of
contaminated soil, it may be more "attractive" to actually treat the material
onsite rather than to tum the site into a large landfill, unless soil is
consolidated into a smaller area which will increase the overall height; thus
potentially making it aesthetically displeasing.
Readily implementable.
Readily implementable. Land Oispoasl Restriction (LDRs) may not allow
disposal of untreated hazardous waste.
Cost
High capital;
moderate O&M
Moderate to high
capital; moderate
O&M
Moderate capital;
high O&M
Low capital; low O&M
Moderate to high
capital; negligible
O&M
Table 3-2 (Continued)
Evaluation of Process Options for Contaminated Soils and Sediments
Sigmons Septic Tank Site
Statesville, North Carolina
------
Threshold Criteria Remedial
Alternative Overall Protection of Compliance with Human Health and the ARAR,
Environment
1 -NoActmn Does not elITT11nate 8)(posure Chemical-specific pathways Of reduce the level ARA~s are not of risk. Does not limit met Location-
migration of or remove and action-
contaminants specific ARARs
do not apply
2 -Excav~tion, Eliminates exposure ARARs are met Treatment With pathways and reduces the through Solidification/ level of risk. Removes d"rect excavation, ons·1te Stabilization and exposure to contamination treatment, and Ons11e Disposal and eliminates further onsite disposal. migration
3 -Excavatron. Eliminates exposure ARARs are met Treatment with pathways and reduces the through Solidifcatiorv'Stabiliza level of risk. Removes excavation, onsIte tion and Offsite contamination and el1111inates treatment, and Disposal in Subtnle D
Landfill
further migrat10n offsite disposal.
------
Table 5-1
Summary of Soil Alternatives Evaluation_
Sigmons Septic Tank Site
Statesville, North Carolina
- -
Balancing Criteria
long-Term Reduction of M/TN Through Short-Term Effectiveness Implementability Effectiveness and Treatment Permanence Tochnical/Englneering Estimated Time for
Considerations Implementation
(years)
The contaminated material No reduction of MITN is level D protactive equipment N= <\ is a long-tenn impact. The realized is required during sampling remediation goals are not
met
long-term public health Reduction of mobility through level C and D protective Treatability testing requtred I threats associated 'Nlth treatment is realized Volume equipment required during site Available space could be a surface so·i1 are greatly may increase activities. E;,:;cavating and problem depending on the reduced. Groundwater is grading may result in potential type of process implemented furth8!' protected through release of dust. Noise TCLP criteria would need to the immobilization of the nuisance from use of heavy be met poor to disposal. Deep contaminants in the soil. equipment excavations may require
dewatering and use of
shootinglshoong
Loog-term public health Reduction of mobility through Level C and D protective Treatabillty testing requlfed. I threats associated with treatment is realized. Volume equipment required d11ing site Available space could be a surface soil are greatly may 111crease activities. Excavating and problem depending on the reducad. Groundwater grading may result in potential type of process implemented would also be protected release of dust. Noise TCLP aiteria would need to through removal of the nuisance from use of heavy be met prior to disposal. Deep source contamination equipment. Treated waste excavations may require
would be transported over dewatering and use of
public roads to the offsite sheeting/shoring. Treated
disposal facilrty. material must meet the Waste
Acceptance Cr'1tena of the
disposal facilrty.
l!!!!!!l I!!!!!! !!!!!!!!I
Cost
Approx. Total Present
WO<lh
S72,000
$2.2 million
S3.8 million
-----
Remedial
Alternative
Overall Protection of
Human Health and
the Environment
1 No Action 0
2 Excavation, 5
Onsite Treatment
with Solidification/
Stabilization and
Onsite Disposal
3 --Excavation, 5
Onsite Treatment
with Solidification/
Stabilization and
Offsite Disposal in
Subtitle D landfill
--
Compliance
withARARs
0
4
5
---
Table 6-1
Comparative Analysis of Soil Alternatives
Sigmons Septic Tank Site
Statesville, North Carolina
Criteria Rating
Long-Te·rm Reduction of MfTN
-
Short-Term
Effectiveness and Through Treatment Effectiveness
Permanence
0 0 5
3 3 4
5 3 3
--
Implementability
5
3
4
A ranking of ~a" indicates noncompliance, while a ranking of ~5" indicates complete compliance.
----
Approximate
Present Worth ($)
$72,000
$2.2 million
$3.B million
-------------------
SIGMON'S SEPTIC TANK SITE
STATESVILLE, IREDELL COUNTY, NORTH CAROLINA SITE VICINITY MAP
N
Figure
1-1
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REFS.· USGS 7.5 MINUTE SERIES TOPOGRAPHIC MAP; TROUTMAN, NC 1993.
SITE LOCATION MAP
SIGMON'S SEPTIC TANK SITE
STATESVILLE, IREDELL COUNTY, NORTH CAROLINA
1" -3,000'
FIGURE
1·2
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REFS.· USGS 7.5 MINUTE SERIES TOPOGRAPHIC MAP; TROUTMAN, NC 1993.
SITE LAYOUT MAP
SIGMON'S SEPTIC TANK SITE
STATESVILLE, IREDELL COUNTY, NORTH CAROLINA
~(.,_~ ~ . v, -N-
J \ ~
(\\
l\
J~v---. '()///"--
" ;,:
•
• .---o--.. .. ~ .
1" = 3,000'
FIGURE
1-3
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D
Legend
• Groundwater Sample Locations
• Sample Exceeds MCL of 15 ug/L for Lead
Sigmon's Septic Tank Site
Statesville, Iredell County
North Carolina
Date
2002
2004
_Q~ResuJUugl!,.)_
2004 1.1
Date Result (ugll\
2004 3.4
Date Result {ug/L)
2004 1.7
Date Result (ug/l)
2002 7.5
2004 2.6
Date Result (u__glU__
2004 140.J
2005 11J
Date Result (ug/L)
2002 5
2004 4.4J
2005 1.6.J
PW,03
-13B. ~ Date Result (ug/L}
2004 16
0 Tu/bidity = 380
PW-01
Date Result (ug/l)
2002 12 □up 4.3
2004 3.8J □up 7.SJ
2005 3.7J
Date
2002
2004
Result (uq/Lj_
3U
2.1
I\
Date Result (ug/l)
2004 1.4
Date Result (ug(!J__
2002 1.4
2004 3.1J
2005 1.1J
Result (ug/l)
2.7J
Date Result /ug/L)
50
Date Result (ug/L)
2002 1.3
2004 1.3J
2005 1.1J Dup 1.3.J
PW-06
Date
2002
2004
2005
Result (ug/l)
1.6
7.SJ
0.74UJ
2002
2003
2004
2005
6A □up 14A Filtered Tap 2.3 Unfiltered Tap 1 U
20.J Dup 8.3.J
4.3J
400 200 0 400 800 1,200
~ ; I I I
Lead in Groundwater Samples
1,600
I Feet
Figure
1-4 I ® I L'::::======~========================~======================================J_1=======1 North Carolina State Plane Coordinate System (NAO 83, Feet)
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MERCURY
Depth Resutt (mg/kg)
2-4' 0.09UJ
10-12' 0.12
MERCURY
Depth Result (mg/kg)
2-4' 0.06U
5-7' 0.06U
10-12' 0.06U
15-17' 0.27
20-22' 0.06UJ
25-27' 0.13U
0
< •
MERCURY
Depth Result (mg/kg)
5-7' 0.12U
10-12' 0.16
----
SS-SB-15 • SS-SB-16
*
MERCURY
Depth Result (mg/kg)
2-4' 0.06U
5-7' 0.06U
10-12' 1.2(2004)
10-12' 0.1U(2005)
SS-S8-17 SS-SB-18 * *
SS-SF/SB-12
SS-SF/SB-F09 •
* SS-SB-21 SS-SF/SB-09
* MERCURY f SS-58-26 Depth Result (mg/kg)
5-7' 0.17 I *
I ""' SS-SF/SB-03
$$-SF/SB-08
* I ~ ss-*-25
SS-SB-24
D
MERCURY
MERCURY Depth Result (mg/kg)
Depth Result (mg/kg) 5-7' 1.6
2-4' 0.17 10-12' 0.21
10-12' 0.11 15-17' 0.35
SS-SF/SB-J05
*
Legend
Mercury non-detects
Not detected in any sample interval; * However, all detection limits are above 0.015 mg/kg
Mercury Concentration mg/kg
@) At least one sample interval exceeds 0.015 mg/kg
Note: See Table 1 for sample results
Sigmon's Septic Tank Site
Statesville, Iredell County
North Carolina
*
North Carolina State Plane Coordinate System (NAO 83, Feet)
LEAD
Depth
5-7'
10-12'
15-17'
SS-SF/SB-C12
*
Result (mg/kg)
280
130
110
SS-SF/SB-01BG
*
igmon Pond
SS-SF/SB-H19
* ---·-·-------·-·----
Mustang Lane
400
Mercury and Lead in Subsurface Soil Samples
200
SS-SF/SB-D23
*
SS-SF/SB-c24
* m
C
0
•
Low Lane
0
Feet
SS-SF/SB-J25
*
Figure
1-5
1r-----------~-----~----------
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j Date Result (ug/L)
2004 350
Date Result (ug/L)
2004 410
D
• Groundwater Sample Locations
• Sample Exceeds 300 ug/L for Manganese
Sigmon's Septic Tank Site
Statesville, Iredell County
North Carolina
Date
2002
2004
Result (ug/L)
5200
9400
Qate Result (ug/L)
2002 17000
2004 19000
TW-05 •
TW-06
\\
e \ Date Result fug/1...)
PP-OS/2,.,_2_004 ___ 11_00 __ ...... _
.?P'07
TW-08
TW~ ,-Da-te_R_e-,u-11-(u-g/L_l_) I
• n~ \ 2004 370 P.P-Q,s/4,.._ _____ __,J
MW-108 •
Manganese in Groundwater Samples
400
I
PW-06 •
800
I
1,200
I
1,600
I Feet
Figure
1-6 I
® ·L-=======-=======~==================~====1_ North Carolina State Plane Coordinate System (NAD 83, Feet)
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Result (mg/kg)
110
11 Depth
2-4'
5-7'
10-12'
Result (mg/kg)
81
BBJ
140J
Dup. (mgfkg)
88J 270 (2005) Depth
2-4'
5-7'
10-12'
15-17'
20-22'
25-27
71
460 (2005) SS-SF/$B-C12
Depth
5-7'
10-12'
490
950J
360.J Dup. (mg/kg)
370..J------960 (2005) 1,300 (2005)
Depth Result (mg/kg) Dup. (mg/kg)
5-7 170.J
10-12' 640J 1600.J
I' - - -,,,...,
I ~ ~ SS-SB-16 ss-~8~7 I SS-SB-15 • •
' .
' 1 ss;-1\
SS-SB-18 • SS-SB-19 •
SS-SF/SB-13 u SS-SF/SB-12
SS-SFISB-F05 •
Result (mg/kg)
180J
690J
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SS-SB-27 •
p ~SS-SB-26
SS-SF/$B-F09 • •
SS-SF/SB-09 •
•
SS-SB-20 •
SS-SB-21 •
~----,./1 • $$-SF/$8-06 SS-SB-22........::
Depth Result (mg/kg)
Depth
3-4'
5-7'
10-12'
15-17
Depth
10-12'
~
SS-SF/$B-08 ..... Pl\ Result (mg/kg)
120 ':::;;:?~•\
250J
790J
430J
SS-SF/SB..J05 •
Depth
2-4'
5-7
10-12'
15-17'
20-22'
25-27'
Result (mg/kg)
260
270
740
390
350J
330J
Legend
Manganese Concentration (mg/kg)
SS-SF/$B(\ • IIlil
--1 SS-SB-23
•ss-SF~B-H09~ .,.._"--,__-_-_-_-_=_=_~_Ill-=--=--=--=-
5-7' 210
10-12' 720
Depth
2-4'
5-7'
10-12'
15-17'
20-22'
25-27'
~ c________:"'i SS.SF/SB-04
Depth Result (mg/kg) Dup. (mg/kg)
Result (mg/kg)
140
400
150
350
930
660J
10-12' 350 470
Dup. (mg/kg)
190
SS-SF/SB-01 BG
• No Sample Interval Exceeds 391 mg/kg
e At Least One Sample Interval Exceeds 391 mg/kg
Note: See Table 1 for sample results
Sigmon's Septic Tank Site
Statesville, Iredell County
North Carolina
North Carolina State Plane Coordinate System (NAO 83, Feet)
•
igmon Pond Q
CJ
CJ SS-SF/SB·H19
Depth Result (mg/kg)
2-4' 450
SS-SF/SB-02 •
Mustang Lane
/400 200
Manganese in Subsurface Soil Samples
SS-SF/SB-c24
SS-SF/SB-D23 •
•
m
C
0 •
~
0 • 0
Low Lane
0
Feet
SS-SF/SB-J25 •
Figure
1-7
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Legend
Date
2002
2004
2005
Result (ug/L)
2.1A
0.98
0.2 Result (ug/L)
44J
380 NTV
Date
2004
Turbidity
PW-03 ;
MW-128 •
Davids n
Pond
C
• 0
0
< •
Groundwater Sampling Locations
Mercury Detections
®
Sigmon's Septic Tank Site
Statesville, Iredell County
North Carolina
North Carolina State Plane Coordinate System (NAO 83, Feet)
Lam ert Pond
PW-04
~
• PW-05
m
C
0
•
PW-08
~ ~-=------=-------1 I
PW-09
• Mustang Lane C
•
MW-108 •
400
Mercury in Groundwater Samples
PW-06 •
200 0
"l!~-~0-l,la;;;;;aa-z
400
Feet
Figure
1-8
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r • C
0
< 0
\
lamber
-SF/SB-017
;r----~-~-----T--=_,,_,m\~OMG/-KG--~=-~""m:::98M::::G/KGJ./
'-\,;le~,{:-~~.. ~ CJ /J1/ \.:;i Sigmoc Po d 1//1
D
Legend
• suriace_cleanup_locations
C Suriace/Subsuriace Soil Cleanup Area (Total Volume to be removed 7224 cubic yard)
1: 1 Stock-pile (Volume = 1349 cubic yard)
Sigmon's Septic Tank Site
Statesville, Iredell County
North Carolina
North Carolina State Plane Coordinate System (NAD 83, Feet)
-SF/SB-G16 SS-SF/SB-022
dlum 210 MG/KG
----
Mustang Lane
Low Lane
200
Area that Exceeds Site Cleanup Goals
l!'.
0.-SF/SB-825 vd•m 120 MG/KG
100 0
---------------
Feet
Figure
2-1
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Appendix A
Detailed Analysis Cost Estimate Worksheets
Altcrnath'e I -No Action PRESENT WORTH COST
Discount Rate: 7%
Site Name: Sigmons Septic Tank Site
Site Locaiion: Srntesville, North Carolina
I I OUA:,.;T!TY 1 UNIT PRICE I TOTAL COST
!TEM DESCRIPTION UNITS DOLLARS DOLLARS
No Ac1ion (5-Ycar Review\ so
I Subtotal. Ca• ital Cost so
Contractor Feet 10% ofCanital Cost) so
I Lt"al Fees, Licenses & Pennits (5% ofCaoital Cost) so
En"ineerin" & Administrative ( 15% ofCaoi1al Cost) $0
Subtotal $0
I Contin"CllC" (25% of Subtotal) so
TOTAL CONSTRUCTION COST $0
I PRESENT WORTH O&M COST $72;347
TOT AL PRESENT WORTH COST $72,347
I Alternative I -No Action OPERATION & MAINTENANCE COSTS
Discow11 Rate: 7%
I Site Name; Sigmons Septic Tank Site
Site Location: Statesville, North Carolina
UNITS QUANTITY UNIT PRICE TOTAL ANNUAL OPERATION PRESENT
I ITEM DESCRIPTION DOLLARS COST, DOLLARS TIME, YEARS WORTH
5-YEAR REVIEWS
Personnel (2-man crew@ 2 12-how days) hours 48 sso $480 30 $5,956
I
Supplies/ Travel days J $3,000 51,800 30 $22,336
Soil/Groundwater Sampling and Lab Tes ting ~ample 20 $500 $2,000 JO $24,818
Rcnort Prenarution lumn sum I 55,000 Sl 000 6 $4,767
O&M SUBTOTAL $5,280 $57,877
I Contractor Fee ( 10% ofO&M cost) $528 $5,788
Le.,al Fees Licenses & Pcnnits (5% ofO&M Cost) $26 $289
I
CONTINGENCY (25% ofSubtornl\ $1,320 $14,469
SUBTOTAL $6.600 572,347
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Al1cm11li~e l -t:1r>1~11tio11, O11si1• T, .. atmc,nt v,/ Solidifiu1ion/S111bliu1ion, PRESENT WORIB COST
11nd O,uil<' Dispou.l
Discount Jute: 7%
Site Namci: Sigmons S<.'ptic T:inl Sile
Sit<.' Lo.:ation. S1a1~,il!c, Nonh Carntinl
U1'1T PRICE TOTAL COST
ITEM DESCRIPTION UNITS l"UANlTJY DOLLARS DOLL\RS
I ,\10131LlZATION/DEMOBILlZATION
Tram port Equipm<'nl & Staff each ' S!00,000 SHI0,000
r._.mpora,y Fa.:ihlles ~"' ' S75,000 sn,ooo
EXCAVATION
I Soil E ... ca,·aiion -Contaminated Soil cy '),000 '" $90,000
Soil E"ca,·.ition. Pisposal Mea ,, •J,500 SlO S•/5,000
Dmt Control & Placement in Stor:ise Alea " !8,500 '" $185,000
BIIClfill faca,·atcd Areas with Clean F,\lrT1<.'11te.l Soil " 18,50.) " S92,500
P!;icc l foo1thiclla)crd""'1fillmcrdisposalsite " 2,200 "" S22.000
I
Place 6 inchtop soil layer over .:,cavaied 111cas cy 2,800 SW S56,000
Grading & Compacting cicre J, S5,000 S 17,500
Seed & Mulch x,o 3' S2,000 S7J)OO
ONSITE TREATME~'T
Trcatability Study lwnpsum ' S50,000 S50,000
I S,1lidifiC11tion/S 1abiliza1ion "" I 1,700 SJO S351,000
EQUIPMENT & MATERIALS
Health & Safety Equipment -' SI00,000 SI00,000
I Subtotal • C..,icaJ Cost Sl,241,000
Comractor fee(ltW.ofC.1 ital Cost) S!24.\00
I Le~al Fees, Licenses & Pcrmi1s (5% ofCaoitaJ Cos!\ $62,050
En~ineccin • & Administrative (15% of ca~ilaJ Cost I $186,150
Subtotal $1 6!3,300
I Contin~encv (25% of Sub!Ot.ifl $403,325
TOT AL CONSTRUCTION COST Sl,016,625
PRESENT WORTH O&M COST $219,626
I TOT AL PRESENT WORTII COST $2 236,251
I Allllmativc ~ •· Eu,11.-.11.Jon, Onsitc T1catmcm "' Solid1fic;ition1Stabli1.11ion, OPERATION & MAINTENANCE COSTS
am! Ons.lc Dispusal
Discount Rate 7"/o
I Si1c Name. SigmoM Septic T;ml S,ce
Site Location· StalL-S\'i!le, North Carolina
UNIT PRJCE TOT AL ANNUAL OPERATION PllESE:-.rT
I ITEM DESCRIPTION UNITS louANTTTY DOLLARS COST, DOLLARS TIME, YEARS WORlll
TREAThmNTSYSTEM MONJTORlNG
Soil Sample Analys..s wccL 52 $2,001) SI04,000 ' $'.17,1%
I
EXCAVATION MONITORING
C,mfirmatory S=plc Analyses samples so S500 $20,000 ' Sl~.6'/2
AIR QUALITY MONITOIONG wc~k 52 tl,000 ~52,0IK) ' $4R,.'i'IH
I.Aw:-; MAIN'fENANCE month " Sl,000 Sl1,000 ' Sl 1,2!5
I S\JRTOTAL SIHK.0\10 SI 7.~.71\l
COl'-TINGEl"sCY (25% of Subtotal) H?,000 S..3,925
I TOTAL $135,000 S119.li26
Tre.1tab1li1y 11udy and soliJificill1on/itab1[j;.11ion ue:itment ca,i. Me from EPA guidance, \~nJor-iupphed tnformJ!ion, JJid similar type "'orL JI other 1iles
l !Oil'" 1 cy
I Cosi. =umc a 1-ye:ir trcalment tune fralfllC
,hsumes a .'i¾ ;n,reasc m ,olume of soil treated na 1olidifica1ion/,1ab1li;.ation
,\55wn,:5 thal ,;oil exc.>Ya.ted from disposal :irea can be used as bacLfill for contaminated :u.:a.
I
Alternative I -No Action PRESl~NT WORTH COST
Discount Rate: 7%
Site Name: Si8111011s Septic Tank Site
Site Location: Statesville, North Carolina
I I OUANTITY I UNIT PRICE I TOTAL COST
ITEM DESCRIPTION UNITS DOLLARS DOLLARS
No Action IS-Year Reviewl $0
Suhtota! -Canital Cost $0
Contractor Fee (10% ofCanital Costl $0
Legal Fees, Licenses & Permits /5% ofCanital Cost\ $0
En~incerin, & Administrative (15% ofCapital Cost) $0
Suhtotal $0
Contin1,tCUCV (25% of Subtotal) $0
TOTAi. CONSTRUCTION COST $0
PRESENT WORTH O&M COST ns,424
TOTAL PRESENT WORTll COST $78,424
A!ccmative I --No Action OPERATION & MAINTENANCE COSTS
Discount Rate: 7'%
Site Name: SiijlllOns Septic Tank Site
Site Location: Statesville, North Carolina
UNITS QUANTITY UNIT PRICE TOTAL ANNUAL OPERATION PRESENT
ITEM DESCRIPTION DOLLARS COST, DOLLARS TIME, YEARS WORTH
5-YEAR REVIEWS
Personnel (2-man crew@ 2 12-hour days) hours 48 $50 $480 30 $5,956
Supplies/ Travel "'' J $3,000 $1,800 30 $22,336
Soil/Groundwater Sampling and Lab Testing sample 20 $50-0 $2,000 JO $24,818
Renort Prenaratiun hmm sum I $5,000 $1,000 6 $4,767
O&M SUBTOTAL $5,280 $57,877
Contractor Fee/ 10% ofO&M cost) $528 $5,788
Le11al Fees, Licenses & Pennits (5% ofO&M Cosn $26 $289
CONTINGENCY 125% ofSuhto1all $1,320 $14,469
SUBTOTAL $6,600 $78,424
Altcrna1ivc 2 -Exc11n1tion, 011silc Treatmenl wl Solidilk11tlon/StablU.a1lo11, PRESENT WORTII COST
and 0111lte Disposal
Discouot Rale: 7'½,
Site Name: Sii;mons Septic Tani. Site
Site Location: Statesville, Nonh Carolina
UNIT PRICE TOTAL COST
ITEM DESCRIPTION UNITS IOUANTITY DOLLARS DOLLARS
MOBILIZA TIONIDEMOEJILIZA TION
Transpon Equipment & Staff each I $100.000 $100,000
Temporary Facilities each I $75.000 $75.000
EXCAVATION
Soil fa,cavation • Contarnina1ed Soil ey 9,000 SIO $90,000
Excavate Onsitc Disposal Area ,y 9,100 $10 $91,000
Excavation Confim1ation Testini; ( 1 test J)l,'1" 100 Ill) tes1 !,089 $100 $108,900
Dust Control & Air Monitorinl,l ,, 18,100 $10 $181,000
Bacltill ExcavateJ Areas with Clca11 Fillffri:ated Soil ,y 18,100 " $90.500
Place 1 foot thick layer clean fill over disposal site cy 2,200 $10 $22,000
Place 6 inchtop soil layer over excavated are-as ,y 2,800 $20 $5(,,000
Gradini; & Compactiui; acre ,., $5,000 $17.500
Seed & Mulch acre ,., $2,000 $7,000
ONSITE TREATMENT
Treatability Study lump SUU1 I $50,000 $50,000
Solidi ficationr'Stabi!ization loo 2,925 SJO $87,750
EQUIPMENT & MATERIALS
Health & Safety l!quipmem each I $100,000 $\00,000
Subtotal • Capital Cost $ 1.07(,,650
Contractor Fee I 10% ofCaoital Cost\ $107,665
l.e1:al Fees, Licenses & Pennits (5% of Capital Cost} SSJ,833
Eo •ineerin • & Administrative 115% ofCanital Cost\ $161.498
Subtoul Sl,399,645
Contin1:ency (25% ofSubtoul) $349,911
TOT AL CONSTRUCTION COST $1,749,556
PRESENT WORTII O&M COST $268,0JS
TOTAL PRESENT WORTH COST $2.017.592
Alternative 2 --Excavation. Onsite Treatment w/ Solidificalion/Stablization, OPERATION & MAINTENANCE COSTS
and Onsitc Disposal
Discount Rate: 7%
Site Name: Sii;mons Septic Tank Site
Site Location: Statesville, North Carolina
UNIT PRICE TOTAL ANNUAL
ITEM DESCRIPTION UNITS OUANTITY DOLLARS COST. DOLLARS
Remedy Monitorinl,l & Five Year Review/Report ycai I SS,280 $5,280
Soil Cap and Lawn Maintenance month " Sl,000 $12,000
SUBTOTAL $17,280
CONTINGENCY 125% of Subtotal I $4.320
TOTAL $21,600
Treat.ability study and solidification/stabilization treatment costs are from EPA i;uiJance, vendor-supplied infom1alion, and similar type worl at other sites.
lcy=I.Jtons
Costs assume a 1-ycar treatment time frame.
Assumes a 5%increase in volume of soil treated via soliJifica1ionls1abiliza1ion
Transportation and disposal costs developed from R.S. Means 1999
OPERATION
TIME. YEARS
JO
30
PRESENT
WORTH
$65.520
$\48.908
S214.428
SSJ,607
$268,035
,\l1trn1ti.-t J -£u:1u1lon, Onshc Trulment "'' Solldlne11lonlStabllza1lon, PRESENT WORTH COST
and Offsi1c llispos1J
Discount Ra1e 7%
Site Name. Sigmol\s Scp1ic Tanl.s Site
Site Loca1ion: Statesville, North Carolina
UNIT PRICE TOTAL COST
ITEM DESCRIPTION UNITS nuANTITY DOI.LARS DOI.LARS
MOBI LJZATlONll)EMOBI LJZA TION
Transport Equipment & Staff =h I Sl00.000 Sl00,000
Temporary J'acili1ies ,~h I S75,000 S75,000
EXCAVATION
Soil Excavation • Contaminated Soil ,, ,,ooo SIO SQ0,000
facavation Confirma1ion Testing ( l 1est per 100 f1 2) ,~, 1,089 SIOO S\08,900
Dust Control & Air Monitoring ,y <l,000 $10 $90,000
Backfill Excava1cd Areas wllh Clean Fill cy 0,000 " 145,000
Place 6 inchtop wil layer over excavated areas cy 1,700 S20 SJ4,000
Grading & Compacting ~" 2.5 $5,000 \12,500
Seed & Mulch ~" ,., $2.000 55,000
ONSITE TREATMENT
Treatability Study lump sum I sso,ooo $50,000
Solidi fic.itiun/Stabil izati,m '"" 2,',25 $JO $87,750
OFFSJTE DISPOSAL
Truck Transport ''" l\,!W, "' S\77,694
Disposal at Subtitle D l.andfill '"" I t,846 !JO \.155,388
EQUIPMENT & MATERIALS
Health & Safety Equipment each I SI00,000 SI00,000
Sub101al -C!lllital Cost SI.JJl,231
Contractor Fee 110% of Ca 1i1al Cost\ Sl.13,123
I ~al Fees, Licenses & Permits (5°/4 of Capital Cost) $66,562
Em1.inecrin11 & Administrative I 15% of Ca 1i1al Cost) Sl'}'),685
SubcOlal Sl,B0,601
Contim1encv /25% of Subtotal) S4J2,650
TOT AL CONSTRUCTION COST S2.H,J.251
PRESENT WORTll O&M COST $26,243
TOTAL PRESENT WORTII COST S2,t8Q,494
Alternative 3 •• E~cavalion, Onsite Treatment wl Solidification/Stablization. OPERATION & MAINTENANCE COSTS
and Offsitc Disposal
Discoum Rate 7%
Site Name. Sigmons Scp1ic Tanks Site
Site Location: Statesville. Nonh Carolin3
UNIT PRICE TOTAL ANNUAL
ITEM DESCRIPTION UNITS OLJANTITY DOI.LARS COST. DOLLARS
Monitoring & Maintenance of Re, Vegetatc<l Arca (.)uancrly 4 S2.000 $8,000
SUIHOTAL $8,000
CONTINGENCY (25% of Subtotal) S2.000
TOTAL 5!0,000
Treatability study and solidification/stabilization tre3tmcnt costs are from EPA guid:mce, vendor•supp!ied inform.uion. and 5imilar type worl at Olhcr sites
lcy-L31ons
C051, ossume a I •year tre3!mem 1ime frame
A5sumes a S¾increase in volume of soil tre.:ucd via solidilication/stabilization
Transportation and disposal C051S developed from RS Means 1999
OPERATION
TIME, YEARS
J
PRESENT
WORTll
S20,99S
$20,995
S5.249
S2b.243
AJtemadve J -Euanlion, OnJite Treatment w/ Solidlflr■tloo/Siablb.alion, PRESENT WORTI--1 COST and Off"1ite Disposal
Diseount Rile: 7%
Sue NDl'lle: Sigmons Septic Tanks Sito
Site Location: Statesville, North Carolina
UNIT PRICE TOTAL COST ITEM OESCIUPTION UNITS OUANTITI DOLLARS DOLLARS
MOBJLIZATION/DEMOBIUZATION
Tram;pol1 Equipmenl & Stall ,.,, I $!00,000 $100,000 Temporary Facilities "" I $75,000 $75,000
EXCAVATION
Soil Excava1ion -Contam.ina1ed Soil cy 9,000 SI0 $90,000 Dusi Control & Placement in Storage Area cy ,.ooo SI0 $90,000 Backfill Excavllled Arca, with Clean FiJVTrea1ed Soil cy ,.ooo " $45,000 Place 6 inchtop J-Oil layer over exca.vllled areas cy 1,700 '20 S34,000 Grnd.ing & Compactina ~" ,, $5,000 S 12,500 Seocl &Mulch ~" '' $2,000 $5,000
ONSITETREATMENT
Treatabllily Study !ump,um I $50,000 $50,000 Solidification/Stabiliution 100 11,700 SJ0 S351,000
OFFSITE DISPOSAL
Truck Transport truckload 6'0 S700 $455,000 Disposal :u Subtitle D Landfill = 12,285 "' $798,525
EQUIPMENT&. MATERIALS
Heallh & Safety Equipment "" I $100,000 Sl00,000
Subtotal -Caoilal Cost $2,206 025 -Contr11etor Fee 110% o(Cllllital Cost\ S220 603
Leaal Fees, Licmses &. Permits (5% ofCAnital Cost I SII0,301
Eniinocrin11: &. Adminisu3tive 05% of Capital Cost) SJJO 904
Subtotal $2 867,833
Continaen"" (25% ofSubtolll) $716 958
TOTAL CONSlRUCTION COST n ss4191
PRESENT WORlli O&.M COST $205,607
! TOTAL PRES8'IT WORTII COST SJ 790 398 -
' I I : --' A11emalive J -facavalion, Onsite Truunent wl So!idtfication/Stab!ization, OPERATION&. MAINTENANCE COSTS 1111d Offsite Dispow
Disco\Ult Rate: 7%
Site Name Sigmons Septic Tanks Site
Site Location: SWe:sville, North_ Carolina
UNIT PRICE TOTAL ANNUAL OPERATION PRESENT ITEM DESCRIPTION UNITS OUA!<ITIY DOLLARS COST DOLLARS TIME YEARS WORTH
PRE•DISPOSAL MONITORING
Soil Sample Analyses ~ul< " $2,000 SI0-.,000 I $97,196
EXCAVATION MONITORING
ConJirm.1tory S1UT1ple Analyses samples 40 $500 $20,000 I S\8,692
AIR QUALITY MONITORING w ...
,.
" SJ,000 ;',!' .. , .. $52,000 I $48,598 ' . ,•., ,. , 2'.;.,:J_,•.
J SUBTOTAL . . '.~,;?:· ft~l76.000 $]64486 .. ' ::.:·1:-..... ,., ~, . COITTINGENCY (25% of Subtotal) ~ •. l\ ', >. S4-1,000 S4I 121
J
.. ,. ~·:u .:-' .. .[;.4;'?:.hF.#$21.oooo TOTAL $205 607 .. .. -,-. r ~;,. ..
J
~ .. ' ' ' ' ~(,;~~/~ Tre11Ulbili1y study .llld solid1fica1ionl11abilization treatment costs an= li"om EPA guidance, vendor-supplied mformatioo, mi similar tyjle~ II ochcrsitcs. lcy.,l.Jlons -, • ~r•~f:;;;~; Co~lll auume a l·yc11t treatment time frame. "\ \ <:..:.t;. •
Asswnes trmispon of 18 10115/truck load and a1·ailability of a disposal t'.ecility within 350 miles. . ::~ rt ~;f:J," ; Assumes a 5%incr=c in volume of soil tr~ed via solidificattonlstabilization , ,, .•·,'t·;:,,;h~:~":i, Transportation and diJposal costs developed from RS. Means 1999 < ~•(J° ~ ,;', )--,,,,
J _::~·~'
"i~