NCD095458527_20090428_FCX Inc. (Statesville)_FRBCERCLA _Groundwater Plume Assessment Work Plan OU-3-OCR

URS
TRANSMITTAL LETTER
115 Water Street, Suite 3
Hallowell, Maine 04347
TO DWM Central Office
1646 Mail Service Center
Raleigh, NC 27699
Attn: Mr. Nile Testerman
Re: FCX (Statesville) Superfund Site (OU3)
We are sending you via [ I hand carry
the following items:
[ [ Specifications
I l USPS
[ X l Work Plan
I ] Test Rcsu Its l I Proposal Request
Item Copies Date
,'
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Project No: 39460365
Reference: FCX Statesville Superfund Site
Date: April 28, 2009
[ X ] Fed Ex
[ l Repons
I J Estimate
I l Prints [ [ Calculations/Data
[ I Copy of Letter/Transmittal
Descrintion
I I April 28, 2009 Groundwater Plume Assessment Work Plan
l X ] For your approval
I I For your use
l For your review & comments f ·1 For your information I J For your signature
I J Returned
[ l
[ [ For your quotation
[ l Executed
[ ] Approval/comments as noted [ ] As requested
[ l Response requested [ ] Please return
---------------------------------------
Remarks: This work is scheduled to begin in mid May.
By: Larry Fitzgerald Title Project Manager
Transmittal Letter. DOC
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Groundwater Plume Assessment
Work Plan
April 28, 2009
FCX (Statesville) Superfund Site (OU3)
Statesville, North Carolina
Prepared For:
EPNG Natural Gas Corporation
1001 Louisiana Street
Houston, TX 77252-2511
Prepared By:
URS
URS Corporation of North Carolina
1600 Perimeter Drive, Suite 400
Morrisville, North Carolina 27560-8421
[o)rEtlE~wlEij
~li APR 2 9 2009 l'::,
SUPEHFUND SECTION
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TABLE OF CONTENTS
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
1.0 INTRODUCTION .............................................................................................................................................. 1-I
I.I
1.2
I .3
1.4
l.3.
1.3.2
1.3.3
PROJECT BACKGROUND AND SITE LOCATION
C0NCEl'T\JAI. SITI' M0l)l,t.
l·IYDR0GEOI.0GICAI. CONDITIONS
Groundwater Occurrence ..
Groundwater Flow ...... .
Hydraulic Properties
GROUNDWATER PLU~·1E CONFIGURATION
......................... 1-1
... 1-2
........................ 1-3
.. ...................... 1-3
.............................. 1-4
............. 1-5
.... 1-5
2.0 OB,JECTIYES ANll SCOPE OF WORK ........................................................................................................ 2-I
2.1
2.2
2.3
CURRENT GtmUNDll',\TER Pt.UME DATA GAPS ..
Oil.I loCTI VES ....
SCOPE OF WORK
................ 2-1
.............................. 2-3
.. 2-3
3.0 GROUNDWATER PLUME ASSESSMENT PLAN ....................................................................................... 3-I
3
3.2
3 I. I
3.1.2
3.1.3
PRl:l,IMINJ\l{Y ACrlV!Tll::S ...... .
Acquire Property Access
Utility Markout/Clearancc.
Clearing and Grubbing
DETl::RM!NATION OF ARE,\ l·IYDR0Gl:0L0CIIC CONDITIONS.
............. 3-1
......................... 3-1
.............................. 3-2
................. 3-2
.3-2
3.2.1 Recharge Assessment....... .. ...... 3-2
3.2.1.1 Approach.. . . .. 3-2
3.2.1.2 Methodology.. .. ................................................................... 3-3
3.2.2 Geophysical Survey.......... .. ..... 3-5
3.2.2.1 Approach.. . ................................................................................................ 3-5
3.2.2.2 Seismic Refraction Survey-tvlcthodology. ..3-()
3 .2.2.3 Seismic Rcllection Survey -Methodology. .. ............................................................................... 3-7
3.2.2.4 Electrical Resistivity Imaging (ERi)-rvkthodology.. . .............................. 3-7
3.2.2.5 Cieophysics Survey Transect Mapping ..................................................................................................... 3-9
3.2.2.6 Reporting.. . .... 3-9
3.2.3 Membrane Interface Probe {MIP) Investigation.... . ................... 3-10
3.2.3.1 1\pproach .. . ............................................................................................................................................ 3-10
3.2.3 .2 l'\'le1hodolog) ........................................................................................................................................... 3-10
3.3 SUl'l'I.EMENTAL MONITORING WELLS, HYDRAULIC TESTING AND MASS Ft.UX ESTIMATES.... .. ... 3-14
3.3.1 Supplemental Plume Delineation/Stability Assessment Wells.. . ........ 3-15
3.3.1.1 Ar1mrnch/l,ocation Rationale.. . ..... 3-15
3.3.1.2 Drilling and \\'di lnstal lat ion -ivkthodology ........................................................................................ 3-19
3.3.2 Borehole Geophysics....... . ................... 3-22
3.3.2.1 Aprroach.. . ...................................................................................................... 3-22
3.3.2.2 tvkthodolog) ........................................................................................................................................... 3-23
3.3.3 Hydraulic Testing -Single Well Tests .... 3-25
3.3.3.1 Approach.. . .................................. 3-25
3.3.3.2 l\·1ethodology-Slug Tests ...................................................................................................................... 3-25
3.3 .3.3 1'-klhodology -Packer Tests.. .. ........... 3-28
3.3.4 Hydraulic Testing-Pumping Tests .......................... 3-30
3.3.4.1 Approach.. . .............................................. 3-30
3.3 .4.2 Pumping Test Methodology -Objectives/Wei I Locations... . .......................... 3-30
3.3.4.3 Pumping Test Methodology-Pre-Test Activi1ies. .. .......... 3-34
3.3.4 .4 Pumping Tes\ i\tkthodology -Stepped-Rate Drawdown Test Procedures.. .. .. .3-J(i
3.3.4.5 Pu111ping Test JVkthodology -Constant Rate Test Procedures ............................................................... 3-37
3.3.4.6 Pumping Test iVkthodology-Pumping Test Data Analysis.... ..3-39
3.3.5 Groundwater/Mass Flux. . ...... 3-40
3.3.5.1 1\rproach .............................................................................................................................................. .3-40
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3.3.5.2 Methodology.
3.4 PLUivlE EVALUATION/MONITORING.
3.4.1 Well/Boring Location Survey
3.4.2 Groundwater Sampling and Analysis ....
3.4.2.1 J\pprom.:h ..
3.4.2.2 1\.-lethodology.
3.4.3 Plume Stability Analysis
3.4.3.1 Approach ..
3.4.3.2 Methodology ..
3.5 UPDATED CSM/DAT,\ GAP INVESTIGATION REPOlrt
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
. .... J-,]11
····························3-43
....... 3-43
..3-43
. .......... 3-4•1
································3-46
..... 3-49
·································3-49
········································3-511
.3-51
4.0 ANALYTICAL PROGRAM AND FIELD OPERATIONS .......................................................................... .4-I
4.1
4.1.1
4.1.2
4.1.3
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.3
ANALYTIC,\L PROGRAM ..
Data Quality Objectives ...
Analytical Methods ....
Quality Control Samples
FIELD OPERATIONS ..... .
Project Team ...... .
Recordkceping ..
Sample Dcsignntion ..
Investigation-Derived Waste ....... .
ANTICll'ATED SCIIEDIII.E
. ........................ .4-1
...... .4-1
···········.4-2
...... .4-2
.. .... .4-3
....... .4-3
...... .4-3
...... .4-5
............................... .4-7
.... .4-8
5.0 REFERENCES ................................................................................................................................................... 5-I
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
TABLE OF CONTENTS (continued)
LIST OF TABLES
Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Table 7
Table 8
Table 9
Data Gaps
Proposed Surface Geophysical Investigations
Proposed Supplemental Well Locations and Rationale
Anticipated Well Construction Specifications
Existing Monitoring Wells Considered for Slug Tests
Proposed Observation Wells for Water Level Monitoring
During Pumping Tests
Proposed Passive Flux Meter Locations
Monitoring Wells to be Sampled as Part of Comprehensive Groundwater Monitoring
Event
Wells Proposed for Statistical Trend Analyses
LIST OF FIGURES
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
URS Corporation
Site Locus
Areas of Potential Groundwater Recharge
Current Understanding of Groundwater Impact in Saprolite
Current Understanding of Groundwater Impact in Bedrock
Current Understanding of Groundwater Impact in Transition Zone
Current Understanding of Vertical Extent of Groundwater Impact
Proposed Geophysical Investigation Locations
Proposed Membrane Interface Probe Investigation Locations
Proposed Well, Passive Flux Meter, and Pumping Test Locations
Proposed Groundwater Sampling Locations and Wells Selected for Statistical Trend
Analysis
April 28, 2009
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AGI
ALT
ANA
API
AS
ASTM
AWD
bgs
cis-DCE
CPT
CSM
CV
cvoc
DC
DNAPL
DOT
DPT
DQO
ECO
EPNG
EPA
ERi
ESD
FCX
FID
FS
GAC
GPS
IDW
mg/L
MIP
URS Corporation
LIST OF ACRONYMS
Advanced Geosciences Incorporated
Advanced Logic Technologies
Accelerated Natural Attenuation
American Petroleum Institute
Air Sparging
American Society of Testing and Materials
Accelerated Weight Drop
below ground surface
cis-1,2-dichloroethene
Cone Penetrometer
Conceptual Site Model
Coefficient of Variation
Chlorinated Volatile Organic Compound
Direct Current
Dense Non-Aqueous Phase Liquid
Department of Transportation
Direct Push Technology
Data Quality Objective
Electron Capture Detector
El Paso Natural Gas Corporation
United States Environmental Protection Agency
Electrical Resistivity Imaging
Explanation of Significant Differences
Farmers Cooperative Exchange
Flame Ionization Detector
Feasibility Study
Granular Activated Carbon
Global Positioning System
Investigation-Derived Waste
milligrams per liter
Membrane Interface Probe
1-4
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
April 28, 2009
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ml/min
MNA
milliliters per minute
Monitored Natural Attenuation
millivolts
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
mv
NCDENR
OU
North Carolina Department of Environment and Natural Resources
Operable Unit
PCE
PDBS
PFM
PID
Tetrachloroethene
Passive Diffusive Bag Samplers
Passive Flux Meter
Photoionization Detector
POTW Publicly Owned Treatment Works
PPE Personal Protective Equipment
PVC Polyvinyl Chloride
QAPP Quality Assurance Project Plan
QA/QC Quality Assurance/Quality Control
RI Remedial Investigation
ROD Record of Decision
RQD Rock Quality Designation
SOP Standard Operating Procedure
SVE Soil Vapor Extraction
SVES Soil Vapor Extraction System
TCE Trichloroethene
µg/1 Micrograms per liter
URS URS Corporation
uses Unified Soil Classification System
µv microvolts
vc Vinyl Chloride
voes Volatile Organic Compounds
YSI Yellow Springs Instruments
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1.0 INTRODUCTION
1. 1 Project Background and Site Location
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
URS Corporation (URS) of North Carolina has been retained by El Paso Natural Gas Company (EPNG), to
provide assistance with the operation, maintenance, performance monitoring and the associated reporting
requirements for the remedy that has been implemented at the Farmers Cooperative Exchange (FCX)
Superfund Site for Operable Unit (OU) 3. OU3 is defined in the Record of Decision (ROD) as on-site and
off-site groundwater that has been impacted by a release(s) of chlorinated volatile organic compounds
(CVOCs), primarily tetrachloroethene (PCE) that is believed to have originated from former dry cleaning
operations at the former Burlington Industries Building, hereinafter referred to as "the Site". The Site is
located along Phoenix Street in the City of Statesville, Iredell County, North Carolina (Figure 1). The dry
cleaning operations were associated with historical textile manufacturing activities performed at the
Burlington Industries Building. Dry cleaning activities reportedly ceased prior to Burlington's ownership of
the manufacturing operation in 1981. The equipment used for dry cleaning and textile manufacturing has
been dismantled and the building is no longer used for textile manufacturing.
The Remedial Investigation (RI) and Feasibility Study (FS) for the Site were completed in 1996. The RI
and FS were conducted to assess the potential sources, nature, and extent of impacts related to CVOCs
released from the Burlington Industries Property and to select a remedial alternative to address these
impacts in groundwater and soil. CVOCs detected in groundwater and/or soil include carbon tetrachloride,
chloroform, 1, 1-dichloroethene, cis-1,2-dichloroethene (cis DCE), 1,2-dichloropropane, methylene chloride,
PCE, 1,2,2-trichloroehtane, trichloroethene (TCE), and vinyl chloride (VC). PCE and its daughter
compounds are the most widespread and PCE is present at the highest concentrations in Site groundwater.
Moreover, PCE is typically present in groundwater at monitoring locations where other CVOCs were
detected. Consequently, remedial efforts have focused on PCE and its daughter compounds.
The United States Environmental Protection Agency (EPA) Region IV and North Carolina Department of
the Environment and Natural Resources (NCDENR) executed the ROD for OU3 on September 30, 1996,
which included:
• Treatment of contaminated groundwater in the source area using air sparging (AS);
• Treatment of soil contaminated with CVOCs using soil vapor extraction (SVE);
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville. North Carolina
• Monitored natural attenuation (MNA) in the downgradient portions of the plume; and
• Monitoring of groundwater entering and exiting the treatment area to assess the effectiveness and
performance of the remedy.
The remedy was fully implemented by 2003. Based upon a review of the first five years of groundwater
monitoring data, attenuation of CVOCs was not proceeding as rapidly as expected. As a result, EPA
signed an Explanation of Significant Differences (ESD) to the ROD for OU3 on September 8, 2006, which
incorporated Accelerated Natural Attenuation (ANA) as part of the remedy. The first phase of the ANA
component of the remedy was implemented during May 2007. Throughout the remedy, EPNG has
monitored environmental media including groundwater and surface water to assess the performance of the
remedy in reducing concentrations of CVOCs in these media.
EPNG recognizes that a significant amount of information has been collected at the Site since the
completion of the RI. EPNG believes that a detailed conceptual site model (CSM) developed from this data
is needed, to fully evaluate the performance of the existing remedy in meeting remedial goals and to guide
future remedial decisions at this Site (e.g., in response to changing regulations such as those that have
recently been implemented for surface water). At EPNG's request, URS has compiled and used the data
collected from the Site to date to develop an up-to-date CSM that provides a quantitative understanding of
hydrogeologic conditions and Site features that may affect the fate and transport of CVOCs originating from
the Burlington Industries Property (URS, 2008). Based upon the CSM, several data gaps were identified
with respect to understanding the extent of groundwater impacts and the behavior of the CVOC plume.
These data are needed to confirm that potential risks are controlled and to evaluate the performance of the
remedy. As a result, EPNG has developed this work plan to identify investigatory activities that will provide
data to address these data gaps.
The remainder of this section provides background information relevant to the groundwater plume
assessment activities proposed in this work plan.
1.2 Conceptual Site Model
The CSM document, previously provided to EPA and the NCDENR, contains detailed descriptions of site
setting and site conditions, a review of previous environmental studies and findings at the Site, detailed
descriptions of both the geologic/hydrogeologic processes and contaminant fate and transpo(t processes
ongoing at the Site, and a quantitative CSM. This work plan does not repeat that information and the
reader is directed to the CSM for that information (URS, 2008). However, the following sections summarize
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
information from the CSM in order to provide the reader with a basic understanding of subsurface
conditions that are specifically relevant to the assessment activities presented in this work plan.
1.3 Hydrogeo/ogical Conditions
1.3.1 Groundwater Occurrence
Consistent with typical groundwater systems of the North Carolina Piedmont, the water-bearing units at the
Site form an upper groundwater system that includes saturated residual soils, saprolite, transition zone, and
the underlying shallow fractured gneiss and schist (historically defined by previous consultants as the
intermediate zone), which generally becomes more competent with depth. All of these zones are
hydraulically connected. The upper groundwater system is unconfined at its upper boundary (the water
table or phreatic surface). The vast majority of monitoring wells located at the Site are screened in the
geologic units that comprise the upper groundwater system (i.e., the saprolite, transition zone, and shallow
fractured bedrock). A lower groundwater system is present in the deeper more competent bedrock. A few
wells penetrated over 100 feet into the bedrock and monitor fractures that could potentially be part of the
lower groundwater system (i.e., wells W-20d, W-28d, and W-33d).
Groundwater is present in the intergranular pore spaces of the saprolite and weathered rock and in the
fractures and other "secondary porosity" features of the bedrock. The saprolite and transition zone are
typically characterized by high porosity, low effective porosity, and low to moderate permeability.
Conceptually, these units are interpreted to act as a storage reservoir for downward infiltrating precipitation.
Fractures within the underlying bedrock act both as a secondary groundwater reservoir and as higher
permeability conduits for groundwater flow within the bedrock. Due to the low effective porosity of fractured
bedrock, groundwater velocities in bedrock fractures tend to be higher than in soils. Therefore, bedrock
contaminant plumes tend to migrate ahead of their counterparts in the overlying soil, consistent with
observations at the Site. A layer of unfractured bedrock sometimes exists between the upper and lower
groundwater systems, resulting in confined, and sometimes artesian, conditions in the lower groundwater
system.
Groundwater generally occurs at depths ranging from less than five feet below ground surface (bgs) near
the drainages north and south of the Site to greater than 40 feet bgs in wells screened in the saprolite and
transition units at the Site beneath the Burlington Industries Building. Bedrock groundwater has been noted
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
to occur under artesian conditions at W-29i, and conversely to occur at more than 90 feet bgs at well W-
33d.
1.3.2 Groundwater Flow
Precipitation enters the Site groundwater systems by percolating downward to the water table (i.e., phreatic
surface) within the saprolite through unpaved areas (Figure 2) and cracks in pavement, and then moves
laterally toward discharge zones, which are manifested as seeps or streams. Some recharge to
groundwater may also occur because of leakage from storm drains and/or sewer lines. Groundwater may
also move downward or upward through the saprolite, weathered rock transition zone and fractured
bedrock in response to changes in vertical hydraulic gradients.
The water table in the saprolite and transition zones at the Site generally mimics the overlying topography.
Water level elevations at the Site (Figure 3) indicate that a groundwater divide extends beneath the
Burlington Industries Building. Groundwater divides are typically indicative of areas of recharge to the
groundwater system. The source of the recharge to the divide beneath the building has not been verified,
but may include leakage from drain lines beneath the building that are connected to roof drains, infiltration
of precipitation and/or run-on from roof-downspouts onto unpaved surfaces, or infiltration from surface
water drainage ditches along the railroad tracks south of the Site.
The general direction of lateral groundwater flow in the upper saprolite beneath the building is northward,
toward an intermittent tributary of Gregory Creek referred to as the Northern Drainage. The general
direction of lateral groundwater flow in the saprolite south of the building is southward, toward an
intermittent tributary of Third Creek referred to as the Southern Drainage. The hydraulic gradient in the
transition zone north of the manufacturing building is also to the north. It should be noted that there are no
transition zone wells south of the manufacturing building other than W-411. It is anticipated that the
hydraulic gradient in transition zone material south of the Site is to the south.
Potentiometric data1 from bedrock wells at the Site indicate that the saprolite, transition zone, and bedrock
are interconnected hydrogeologic units. Lateral groundwater flow in bedrock is toward surface water
drainages to the north and south (i.e. Gregory Creek and Third Creek) that are inferred to be receptors of
Site groundwater.
1 Potentiometric data are groundwater pressure heads measured at depth below the water table or
phreatic surface. For this report, the phreatic surface was defined using wells screened across or near
the water table in the saprolite.
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\ Groundwater Plume Assessment Work Plan
FCX (Statesville) Superfund Site (OU3)
Statesville, North Carolina
The historical operation of pumping wells in the area appears to have affected the distribution of CVOCs in
groundwater. The most dominant example is the operation of the former Carnation Milk Company
groundwater pumping well, which has potentially resulted in spreading of the plume to the west in the
bedrock. The Carnation Well is no longer active and thus, is no longer affecting impacted groundwater at
the Burlington Industries Site. Another pumping well (i.e., the industrial process well for the Slane Glass
Company) and potentially, dewatering of a 300 foot deep quarry located approximately one mile north of
the Site (Figure 1), may be influencing the spread of the plume in a northerly direction. The potential
influence of the pumping of the Slane Glass well is inferred by low concentrations of CVOCs detected in a
groundwater sample from the Slane well collected during 2005.
1.3.3 Hydraulic Properties
Hydraulic properties of the saprolite and transition zone have been studied through two sets of pumping
tests and several slug tests performed at this and the adjacent FCX site. Based on results from these
pumping tests, bulk hydraulic conductivities are expected to range from approximately 4 X 10-3 to 5 X 10-4
cm/sec for the deeper saprolite and transition zones at the Site. There are no reliable hydraulic conductivity
data for the shallow saprolite or fractured rock zones. Based upon general observations of soil consistency
and structure, an understanding of the weathering processes that result in the formation of saprolite, and
the vertical and horizontal distribution of CVOCs, the hydraulic properties of the saprolite, transition zone,
and fractured bedrock are likely to vary in space and in direction (i.e. anisotropic conditions exist).
Anisotropic conditions may play a significant role in the fate and transport of CVOCs. Anisotropy has not
been specifically evaluated during previous studies. Activities presented in this work plan will provide data
to assess anisotropy and its influence on the fate and transport of CVOCs in groundwater. Furthermore,
data collected as part of this work plan will provide quantitative estimates of the hydraulic properties of
fractured bedrock and a broader understanding of hydraulic properties in saprolite and the transition zone
across the area of the CVOC plume.
1.4 Groundwater Plume Configuration
The groundwater plume in saprolite and shallow fractured bedrock, which contains PCE and its daughter
compounds, extends to the north and south from a groundwater divide beneath the building as shown on
Figures 3 and 4. Concentrations of PCE in groundwater in some wells beneath and downgradient of the
Burlington Industries Building (i.e. W-17s) exceed 20 percent of the aqueous solubility of PCE, which infers
that dense non-aqueous phase liquid (DNAPL) is present in saturated soils below the Burlington Industries
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
Building. The plume appears to correlate with a northwest-southeast trending bedrock fracture lineament
identified during the photolineament study presented in the CSM. In the area north of the Site, it is thought
that a bedrock trough may be parallel or coincident with the lineament and could be controlling the
distribution of PCE in the groundwater. Pumping tests conducted in the area indicated a potential response
in wells located near and along the alignment of this feature and infer that anisotropy in the bedrock (and
possibly the transition zone) is northwest to southeast, suggesting a zone of higher hydraulic conductivity in
the bedrock along this alignment.
The extent of the CVOC plumes within the saprolite and bedrock units is similar geometrically and in
orientation, as shown on Figures 3 and 4. Impacted groundwater extends more than 1,200 feet
north/northwest of the manufacturing building in the saprolite and fractured bedrock groundwater systems.
The northerly extent of impacted groundwater is not well defined. The southerly plume extends
approximately 700 feet south of the manufacturing building in the saprolite and approximately 1,800 feet
south in fractured bedrock using the 0.7 micrograms/Liter (µg/L) regulatory criterion as the basis for
defining the extent of impact. Based upon March 2007 analytical data, impacted groundwater above the
0.7 ,1g/L regulatory standard in saprolite is interpreted to extend laterally approximately 260 feet east and
approximately 160 feet west of the manufacturing building. While the concentrations of PCE in bedrock
groundwater decrease to the east and west of the manufacturing building, concentrations of PCE at the
lateral monitored portions of the shallow fractured bedrock plume are greater than the 0.7 µg/L regulatory
criterion. Therefore, the width of the plume in shallow fractured bedrock is not well defined.
A significant feature of the PCE plume in fractured bedrock is an extension of the plume along the west
side of the manufacturing building that extends more than 250 feet toward the direction of the former
Carnation Property. This extension of the plume is defined by wells W-2i, W-Bi, W-9i, and W-12i and is
characterized by low concentrations of PCE (i.e., on the order of 10 µg/L or lower). One possible
explanation of this extension of the plume is that the Burlington Property was located within the hydraulic
radius of influence of the industrial supply well located on the former Carnation Property. As a result,
impacted groundwater may have been drawn toward the well under active pumping conditions. This well is
no longer active. PCE has spread vertically into the fractured bedrock to a depth of more than 250 feet
bgs. The vertical extent of the CVOC plume has not yet been defined. Activities proposed in this work
plan will help to better delineate the lateral and vertical extent of the CVOC plume and will help to quantify
groundwater and mass flux across the plume.
URS Corporation 1-6 April 28, 2009
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The balance of the work plan is presented in three sections as follows:
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
• Section 2.0 presents the objectives of the groundwater plume assessment presented in this work
plan and summarizes the scope of work that has been developed to address these objectives;
• Section 3,0 presents details of the groundwater plume assessment work plan including pre-
investigation activities, monitoring locations, rationale of specific activities and monitoring locations,
and investigatory methods to acquire data; and
• Section 4.0 provides quality assurance/quality control (QA/QC) procedures related to data
acquisition and management.
This work plan also provides a proposed schedule for completing groundwater plume assessment
activities.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
2.0 OBJECTIVES AND SCOPE OF WORK
2.1 Current Groundwater Plume Data Gaps
Data gaps related to groundwater have been identified through the development of the updated CSM. The
data gaps relate to:
• delineating the downgradient, vertical, and lateral extent of the CVOC plume;
• identifying and quantifying sources of groundwater recharge;
• identifying and characterizing areas of groundwater discharge proximal to the Site;
• characterizing the geological and hydrogeologic properties of the saprolite, transition zone and
bedrock in areas impacted by the plume and geologic features that may control the location of the
plume; and
• quantifying mass flux within the plume.
As indicated by the CSM, it appears that impacted groundwater on the north side of the building may be
migrating in a more northwesterly direction than previously thought, towards Waverly Place and the
Statesville Business Park. Most of the downgradient wells north of the Site are located along a northerly
alignment parallel to overland flow from a groundwater seep that discharges to the Northern Drainage and
may not be intercepting the core of the plume. Consequently, as shown on Figures 3 through 6, the
northerly downgradient extent of the PCE plume does not appear to be fully delineated in either bedrock,
transition zone material, or the saprolite. Although unconfined, there is some indication that the bedrock
plume could potentially be moving along a suspected northwest/southeast trending fracture zone, and PCE
transport in the saprolite and transition zone may be influenced by the weathered remnants of such a
feature, if it exists. Laterally, the extent of impacts is not well defined in the bedrock aquifer in areas to the
north, south or to the east of the Site, as shown on Figure 4.
Data gaps for which a greater understanding is needed were identified in the updated CSM and have
served to guide the activities proposed in this work plan. These data gaps are presented in Table 1. The
data gaps relate to source characterization, vertical and lateral delineation and characterization of the
plume, and geological and hydrogeologic evaluations. In summary, the data are needed to assure that
potential receptors are known; potential risks to receptors are adequately controlled; and to support a
predictive groundwater fate and transport model to forecast the behavior of the plume in response to the
current remedy.
URS Corporation 2-1 April 28, 2009
-------------------Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
TABLE 1 DATA GAPS
FCX Statesville Superfund Site
Statesville, North Carolina
Data Gap .. -Activities Proposed to Fill Data Gao
The lateral and horizontal extent of the plume in the saprolite, transition zone Drilling And Monitoring Well Installation,
and bedrock units are not sufficiently defined. Borehole Geophysics,
Membrane Interface Probe Investigation, and
Groundwater Sampling
Mass and groundwater flux across representative cross-sections of the plume Supplemental Monitoring Well Installation, and
are not well quantified. Groundwater/Mass Flux Measurements
Hydraulic conductivities (horizontal and vertical) and variability within the Hydraulic Testing (slug and Packer tests) and Pumping Tests
various layers that make up the aquifer are not adequately defined.
The bedrock surface topography at the Site, which may be influencing the Surface Geophysical Survey
location and orientation of the plume, is not well defined.
The presence and location of major fracture zones within the rock, the Surface Geophysical Survey, Borehole Geophysics,
geometry of these zones, and the hydraulic conductivities of the bedrock within Hydraulic Testing (slug and packer tests) and Pumping Tests, and
and outside these zones have not been confirmed or quantitatively assessed. Groundwater Sampling
Sources of groundwater recharge and recharge rates in the area are not Recharge Assessment
quantified and these factors affect mass flux.
Groundwater discharges in close proximity to the Site and is not adequately See Surface Water Assessment Work Plan (URS, 2009) as well as installation
characterized or defined. of membrane interface probe borings and monitoring wells described in this
work plan.
URS Corporation 2-2 April 28, 2009
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2.2 Objectives
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
I Based on the Site data evaluation conducted as part of the CSM, URS has developed an assessment
program for the delineation of the groundwater CVOC plume that will provide plume definition and
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geological and hydrogeologic data to address the data gaps described in Table 1. The objective of this
investigation is to gather information that will be used to:
• Validate or refine the CSM and verify that potential exposure pathways to impacted media are
controlled;
• Confirm/delineate the vertical and horizontal extent of groundwater impacts and help confirm
the sources of the impacts;
• Provide an assessment of factors that could affect the performance of the OU3 remedy;
• Assess the effectiveness of the existing remedy in attaining cleanup goals established by the
ROD;
• Guide future remedial decisions to manage risk, if needed;
• Support the development of a groundwater flow and transport model (described in a separate
work plan) to forecast changes in response to the remedy and to evaluate potential
effectiveness of alternative technologies on reducing plume longevity, concentration
distribution, and extent; and
• Develop performance matrices for remedial measures undertaken at the Site.
I 2.3 Scope of Work
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The tasks to be accomplished under the Groundwater Plume Assessment Work Plan can be grouped into
four groups with common elements relative to implementation, timing, and purpose/type of investigative
task. These tasks are listed below:
Preliminary Activities
1. Acquire Property Access. This task will establish legal agreements that allow investigative
activities to be conducted on properties owned by others.
2. MarkouUUtility Clearance. Proposed intrusive investigation locations will be marked in the field.
Utility clearances will be established_ to avoid damage to subsurface utilities and to protect workers.
3. Grubbing and Clearing. Clearing of brush and/or debris will be performed as needed to facilitate
surface geophysical investigations.
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Determination of Area Hydrogeologic Conditions
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
4. Recharge Assessment. A recharge assessment will be conducted to evaluate the impacts of
direct and indirect contributions of Site groundwater recharge to a groundwater mound underlying
the Site, and to determine whether actions should be taken to control recharge inputs.
5. Surface Geophysical Survey. Surface geophysical surveys will be conducted to: evaluate depth
to bedrock within the immediate vicinity of the Site and within several residential neighborhoods
bordering the Site; evaluate whether photolineaments identified in the CSM correspond to bedrock
fracture zones and to delineate such bedrock fracture zones, should they exist; identify potential
low points along the bedrock surface that may control the movement of DNAPL and the distribution
of contaminants in groundwater; and to evaluate, to the extent practicable, the thickness of an
interpreted saprolite and transition zone overlying competent bedrock. The results of the
geophysical survey will also be used in combination with existing information to: guide the selection
of suitable locations for borings and groundwater monitoring well installations to delineate the
extent of the plume; assess whether DNAPL is present in low points in the bedrock surface near
and immediately downgradient of release areas; and provide stratigraphic data to assist in
developing the framework for the groundwater flow and transport model referenced in the previous
section.
6. Membrane Interface Probe (MIP) Investigation. The MIP investigation will assist in defining the
downgradient extent of the CVOC groundwater plume in saprolite and possibly the transition zone.
This information will, in turn, be used to assist in determining the appropriate number and locations
of monitoring wells to be installed to define the downgradient extent of the CVOC plume.
Monitoring Wells, Hydraulic Testing and Mass Flux
7. Drilling and Monitoring Well Installation Program. Monitoring wells will be installed to provide:
groundwater analytical data to delineate the vertical and lateral extent of the CVOC plume
originating frorn the Site; to help quantify the vertical mass flux from the source area; and to
provide water level observation points for use during hydraulic/pumping tests.
8. Borehole Geophysics Survey. Borehole geophysics will be performed at selected locations to
locate potential water-bearing fracture zones to help identify monitoring intervals for packer testing
and well screen placement in bedrock to help delineate the vertical extent of the plume.
9. Single Well Hydraulic Testing. Two types of single-well hydraulic testing (i.e. slug tests and
packer tests) will be performed on each newly installed monitoring well and rock boreholes as well
as on a subset of existing wells, to obtain estimates of the hydraulic properties (i.e., transmissivity,
hydraulic conductivity, and/or storativity) of the saprolite, transition zone, and the fractured bedrock.
The hydraulic properties data obtained from these tests will be used to develop a predictive
groundwater flow and transport model for the Site.
10. Aquifer Pumping Tests. The primary purpose for conducting pumping tests will be to determine
site-specific aquifer properties including hydraulic conductivity (K), transmissivity, specific yield,
and storage coefficients. These properties are necessary to characterize the spatial hydraulic and
storage properties of each water-bearing zone (i.e. saprolite, transition zone, and fractured
bedrock) and to evaluate anisotropy, and to the extent allowable by the data, identify aquifer
boundary conditions. Data will be used to refine the CSM as well as provide site-specific
quantitative data needed to construct a predictive groundwater flow model. The pumping test will
URS Corporation 2-4 April 28, 2009
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
include the following field activities: collecting water level data to assess ambient trends and
normalize drawdown/recovery data collected during the pumping test; performing stepped-rate
drawdown tests for each hydrogeologic unit to determine and optimal pumping rate for constant-
rate pumping tests; performing a constant rate pumping tests for each hydrogeologic unit; and
monitoring subsequent water level recovery.
11. Groundwater/Mass Flux Estimates. The data gained from these activities will be used to provide
an understanding of the mass of PCE leaving the source area, which when coupled with an
understanding of PCE mass in the source, can be used to provide an estimate of the life
expectancy of the source area, and provide a mechanism for assessing the calibration of the
groundwater flow and transport model. This activity will involve deploying and retrieving mass flux
meters for analysis by Enviroflux to quantify groundwater flow and mass flux of PCE from the
source area.
Plume Monitoring
12. Survey. Each newly installed monitoring well will be surveyed for location and elevation and
referenced to the existing monitoring network.
13. Comprehensive Round of Groundwater Sampling and Analysis. Groundwater sampling will
be performed at new monitoring well locations and select existing wells to demonstrate that the
plume is adequately delineated and to provide a calibration data set for use in the predictive
groundwater flow and transport model for the Site.
14. Refine Monitoring Well Network to Monitor Plume Stability. The goals of the refined
monitoring program for the Site include the following: demonstrate that the plume is adequately
delineated; demonstrate that the plume is not expanding; and assess changes in the concentration
distribution in the plume, in response to implemented remedial actions and natural processes.
The details regarding activities associated with each of these tasks are presented in Section 3.0.
URS Corporation 2-5 April 28, 2009
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
3.0 GROUNDWATER PLUME ASSESSMENT PLAN
Consistent with standard practice, URS has used the CSM to identify areas where additional investigation
is warranted to delineate the extent of the CVOC groundwater plume. These data will facilitate our
assessment of areas of potential groundwater receptors as well as locations where vapor intrusion might be
a potential concern. Information obtained from these investigations will provide a logical, scientifically
supported approach to confirming that potential risks are adequately managed. In addition, the
supplemental groundwater plume assessment activities described here will provide data needed for
development of the groundwater flow and transport model for the Site, which will be used to help predict the
performance of the existing and potential alternative remedial approaches with respect to:
• meeting clean-up goals;
• reducing the longevity of the plume;
• reducing the extent of the plume, and;
• reducing contaminant concentrations within the plume.
This Groundwater Plume Assessment Work Plan includes the activities previously identified in Section 2.3.
These activities are described in detail in the following sections.
3.1 Preliminary Activities
Preliminary activities to be conducted prior to initiation of investigative activities include establishing
property access agreements, utility clearances, and brush clearing.
3.1.1 Acquire Property Access
The groundwater plume assessment described in this section encompasses commercial and private
properties owned by others and will require access agreements in order for investigative activities to be
conducted at these locations. EPNG and URS will endeavor to identify, contact, and obtain permission
from property owners as needed prior to initiating proposed investigation activities. Formal access
agreements will be sought with property owners to allow EPNG/URS personnel to access groundwater
assessment locations. In the event that certain property owners do not grant access, EPNG may seek
assistance from NCDENR and/or EPA to secure access or, if unavoidable, alternative assessment
locations will be selected.
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3.1.2 Utility Markout/Clearance
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
Proposed exploration locations shown on Figures 7 through 9 will be confirmed and marked in the field by
URS prior to conducting intrusive subsurface activities. Utilities will subsequently be located and marked
using one of two procedures. For those areas that fall on public property, URS will notify the North Carolina
One Call Center, the public utility locator service, which will mark any utilities that are known to exist near
the explorations. The locations shall be marked at the land surface using spray paint and industry standard
practices. For those investigation locations that fall outside of the responsibility of the NC One Call Center
(i.e., locations on private property), URS will use geophysical sensing equipment and/or vacuum excavation
to confirm that exploration locations are clear of subsurface utilities.
3.1.3 Clearing and Grubbing
Brush clearing and grubbing will be conducted to the extent necessary to provide the needed open space
and run length to conduct the geophysical investigations along the proposed transect lines shown on
Figure 7. Brush will be cleared and left on-site or removed as determined in the field based upon
discussions with property owners.
3.2 Determination of Area Hydrogeo/ogic Conditions
An assessment of recharge conditions, surface geophysical surveys, and a MIP investigation will be
conducted to evaluate hydrogeologic and contaminant conditions in areas proximal to the Site.
3.2.1 Recharge Assessment
As described earlier, a groundwater divide (Figure 2) extends beneath the Burlington Industries Building
through the primary CVOC source area. The presence of the divide may be, in part, the result of localized
groundwater recharge.
3.2.1.1 Approach
An understanding of the sources of recharge is important because the amount of recharge infiltrating soils
beneath the Site may affect the height of the groundwater divide and thus hydraulic gradients beneath the
source area, which directly affects the magnitude of mass flux and downgradient extent of the plume. In
addition, recharge estimates obtained from the assessment will be used in the development of the
proposed predictive groundwater fate and transport model. The focus of the recharge assessment will be
the area overlying the groundwater divide, and generally covered by the existing former Burlington
Industries building.
URS Corporation 3-2 April 28, 2009
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
To the extent practicable, the degree to which on-site anthropogenic groundwater recharge contributions
are affecting plume extent will be evaluated and it will be determined whether actions should be taken to
reduce recharge inputs as a means of reducing mass flux from this Site and potentially reducing the extent
of the dissolved CVOC plume.
The recharge assessment will include three components, as follows:
• Determine natural, direct recharge conditions for the Site;
• Document and characterize, to the extent practicable, any indirect inputs to groundwater recharge
(e.g. leakage from drains or leaks from waterlines); and
• Assess the dynamics of groundwater level fluctuations on the Site in response to precipitation.
I 3.2.1.2 Methodology
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The first step of the recharge evaluation will focus on obtaining key data necessary to determine natural,
direct recharge conditions for the Site. The quantity of precipitation that falls on the Site/area is the
foundational data point for recharge calculations. To collect the basic data needed to perform an
assessment of recharge, precipitation data will be obtained from the nearest of three National Climatic Data
Center stations located in Statesville. Recharge is also affected by the characteristics of the land surface
where precipitation and drainage from impervious (e.g., the roof of the building) to pervious surfaces (e.g.,
grassed area south of the building) occur. Areas presumed to be relatively impervious along with areas
presumed to be pervious based upon observations of surface cover are shown on Figure 2. The recharge
area will be subdivided into groups based on land use/land cover and slope. Standard runoff coefficients for
various cover materials will be used to estimate the portion of precipitation that contributes to groundwater
recharge versus surface runoff. This analysis will employ the use of Geographic Information Systems
software and publicly available data (e.g., topography, aerial photographs, etc.).
The second evaluation step will be to document and characterize any indirect inputs to groundwater
recharge from anthropogenic sources. In the case of OU3, this evaluation may include the following:
• Surface drainage features (e.g., natural stormwater/runoff retention/ponding, stormwater pipes,
culverts, etc.) associated with the railroad or roads bordering the Site will be located and evaluated.
If accessible, leakage tests will be performed on conveyance pipes for the roof drains above the
groundwater divide. The leakage tests will be performed by introducing a known flow of water into
the most upstream roof drain along a collection header and monitoring the flow at the end of the
conveyance pipe. The difference in flow rate can be inferred to be the leakage rate from the pipe.
If it is assumed that the percentage of the total flow leaking from the pipe can be applied to the
volume of precipitation falling on the impervious area draining to the roof drains during a given year
and that there is no net loss of precipitation (e.g., through leaks in the rooD, the annualized
URS Corporation 3-3 April 28, 2009
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
recharge from the conveyance piping can be reasonably approximated as a percentage of the
annual volume of precipitation falling on the contributing area for that drain.
• Water lines that cross this portion of the Site over the area of the divide will be identified and
evaluated for leakage.
• A video survey will be conducted on drain conveyance piping and sewer lines crossing the area of
the groundwater divide where accessible, to determine the integrity of the piping and to look for
breaks/leaks.
Data and information generated from the evaluation of potential indirect anthropogenic sources will be
assimilated with site recharge data to develop and quantify Site recharge parameters in/near the suspected
source areas.
A third evaluation step will focus on assessing the dynamics of groundwater level fluctuations on the Site to
obtain additional data to assess potential differences in the magnitude of groundwater recharge in the
immediate vicinity of the Burlington Industries Building as compared to background areas located away
from anthropogenic sources of recharge.
A standard approach for quantifying recharge is to monitor the response of the water table to precipitation
events. Recharge using this approach can be estimated using the following expression:
R = Sy(llh/t)
Where: R = recharge rate for a given storm event (length);
Sy= Specific yield of the water-bearing formation (in this instance, saprolite); and
llh/t = Groundwater response to a specific recharge event (length/time).
Using pressure-sensitive transducers equipped with dataloggers, water level data will be collected from
select shallow wells positioned in/around the Site's groundwater divide. Water levels will be monitored for
an extended period of time (i.e. approximately one to three months) at approximately 15-minute intervals
during two separate monitoring events in an attempt to assess the magnitude of groundwater fluctuations in
response to precipitation (recharge) events. One event will be conducted in the Spring and Summer when
precipitation occurs as a result of short duration high-intensity storms. The second monitoring event will be
conducted during fall/winter when precipitation typically occurs over longer durations at lower intensity.
Water level fluctuations in wells that are located adjacent to the south side of the building and in areas that
appear to receive drainage from the roof drains (W-2s through W-5s, and W-1 ?s) will be compared with
water level fluctuations in wells in areas that may not receive indirect anthropogenic sources of recharge
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Superlund Site (OU3)
Statesville, North Carolina
(i.e., MW-8 and W-15s which are located closer to the former Carnation Plant). Changes in water levels
will be evaluated using Sy determined from previous pumping tests and referenced in the CSM to determine
areas of greater potential recharge and to determine if a correlation exists between groundwater levels and
potential anthropogenic sources of excess recharge near the plant. If such a correlation is identified, URS
will assess (e.g., through groundwater modeling) the extent to which reducing indirect anthropogenic
sources of recharge near the building could lower the hydraulic gradient at the Site and as a consequent
reduce mass flux. It is imperative that this evaluation also consider the potential for redistribution of the
plume. Pending the findings of such an assessment, EPNG may consider steps to reduce recharge above
the groundwater divide as a means of reducing mass flux from this Site.
3.2.2 Geophysical Survey
A combination of seismic refraction, seismic reflection, and electrical resistivity imaging (ERi) surveys will
be used to characterize bedrock conditions beneath the Site and the surrounding neighborhoods.
3.2.2.1 Approach
The objectives of the geophysical investigation include the following:
• Evaluate depth to bedrock within the immediate vicinity of the Site as well as within several
residential neighborhoods bordering the Site;
• Delineate bedrock fracture zones, if any, associated with photolineaments identified in the CSM
that may serve as preferential flow paths for contaminants;
• Identify potential low points along the bedrock surface downgradient of release areas that could
potentially serve as collection points for mobil~ DNAPL, if present, and control the location of the
dissolved CVOC plume; and
• Evaluate the thickness of the interpreted saprolite and transition zone overlying competent
bedrock.
The results of, these geophysical investigations will be used to:
• Guide the selection of suitable locations for groundwater monitoring well installations to better
define the limits of the plume and assess the significance of the role of bedrock fractures in the
transport of PCE and its daughter compounds and the extent of the CVOC plume in bedrock
groundwater as discussed in Section 3.3;
• Assess whether low points exist in the bedrock surface near and immediately downgradient of
release areas that could potentially intercept and accumulate DNAPL; and
• Provide stratigraphic data to assist in developing the framework for the groundwater flow and
transport model referenced earlier.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
In order to facilitate a discussion of the geophysical survey, the proposed area of investigation has been
subdivided into four areas, which are summarized in Table 2. Geophysical survey transects for the seismic
and ERi surveys are shown on Figure 7.
Descriptions of seismic refraction, seismic reflection, and ERi methods are provided below. URS will
subcontract the seismic reflection survey to a qualified geophysical consulting firm that is capable of
performing the robust data analysis and interpretation required with seismic reflection surveying, URS will
conduct the remainder of the geophysical investigation (i.e., seismic refraction and ERi),
3.2.2.2 Seismic Refraction Survey -Methodology
Seismic refraction will be used to map depth to bedrock and identify stratigraphy in areas where bedrock is
typically present at less than 75 feet bgs. The seismic refraction method consists of transmitting seismic
energy into the ground and recording the arrival of the direct and refracted compressional-waves (P-waves)
at preset distances along the ground surface. By evaluating seismic velocities, as inferred from the
recorded first arrival travel times, and the seismic velocity contrasts, the investigator can interpret the
stratigraphy and depths of the subsurface geologic units.
A Geometrics Geode seismograph, or an equivalent system, will be used for the seismic refraction survey
performed at the Site. The proposed energy source will consist of a vehicle-mounted accelerated weight
drop (AWD) source that operates using a closed gas-charged system to accelerate the drop of a 100-
pound hammer from a height of approximately 18 inches. This robust gas-charged system is highly
efficient and can deliver substantially more energy into the ground compared to sledgehammers or other
traditional AWD sources. A 16 or 20-pound sledgehammer will be used on a limited basis in residential
areas that may not be accessible with the AWD.
The seismic refraction survey will involve collecting data along 29 individual transects (Figure 7). One
transect will be positioned at a remote location to the northwest of the Site in order to characterize
subsurface conditions and identify potential bedrock fracture lineaments near a local quarry. Where the
seismic refraction and ERi transects (Section 3.2.2.4) are co-located, the seismic refraction transects will
be positioned to match, as closely as possible, the locations of the ERi transects. Final placement of the
seismic refraction transects may differ from the locations shown on Figure 7 based on encountered
limitations associated with property access or unanticipated physical constraints.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
The total length of the proposed transects (including the remote location) is 13,800 linear feet. The lengths
of individual transects vary from approximately 230 feet to approximately 2,000 feet. Data will be collected
using a uniform geophone spacing of approximately 10 feet and a uniform interior shot point spacing of
approximately 40 feet. The relatively short distance between shot point locations is intended to provide
increased lateral resolution in characterizing subsurface conditions. Where physical site conditions permit,
additional shot point locations will be positioned, at a minimum, 50 feet and 100 feet off both ends of each
transect.
3.2.2.3 Seismic Reflection Survey -Methodology
Seismic reflection will be used to evaluate the depth to bedrock surface, bedrock stratigraphy, and to help
delineate suspected deep fracture lineaments in areas where bedrock is anticipated to occur at greater
than 75 feet bgs, such as in the area immediately northwest of the Site. A seismic reflection survey utilizes
much of the same type of equipment as a seismic refraction survey, except that the method measures the
arrival time of the reflected seismic energy wave from a subsurface interface as opposed to the refracted
wave.
The seismic reflection survey will involve collecting data along 9 individual transects (Figure 7), Where the
seismic reflection and ERi transects (Section 3.2.2.4) are co-located, the seismic reflection transects will
be positioned to match, as closely as possible, the locations of the ERi transects. Final placement of the
seismic reflection transects may differ from the locations shown on_ Figure 7 based on encountered
limitations associated with property access or unanticipated physical constraints.
Approximately 7,260 linear feet of seismic reflection data is proposed as part of this investigation.
Individual transect lengths will vary between approximately 550 feet and approximately 1,100 feet.
3.2.2.4 Electrical Resistivity Imaging (ERi) -Methodology
The primary purpose of conducting ERi is to evaluate depth to suspected fracture zones. The method
relies on the principle that different subsurface materials resist the flow of electrical current to varying
degrees. A material's resistance to electrical current is measured as the ratio of electrical potential, or
voltage (v), to the applied current (I). Resistivity (p) is the ratio of resistance over the cross-sectional area
of a material that the current passes through,
In general, soil and rock act as electrical insulators and are highly resistive. Consequently, the flow of
electrical current is primarily through moisture-filled pore spaces. The observed resistivity is controlled by
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
the following: rock composition, porosity, permeability, amount of water within the pore spaces, and the
concentration of dissolved solids within the pore fluids. Therefore, resistivity measurements can yield useful
information for the characterization of the stratigraphy, structure, and composition of the subsurface,
including the locations of fracture zones.
A direct current (DC) electrical resistivity survey is performed by placing two pairs of electrodes in the
ground and connecting them to a power source to create a simple electric circuit in the subsurface. An
electric current is passed through two of the electrodes (i.e. current electrodes), and the resulting voltage is
measured at various locations along the ground surface between a second pair of electrodes (i.e. potential
electrodes). Subsurface resistivity values are calculated from the separation and geometry of the electrode
positions, the amount of applied current, and the measured voltage across the potential electrodes. There
are several types of electrode arrays that can be used to collect electrical resistivity data. The most
common arrays used in environmental and engineering surface applications include the Wenner,
Schlumberger, and dipole-dipole arrays. The dipole-dipole electrode configuration will be utilized at the
Site because it provides the optimum depth of penetration and resolution relative to the project objectives
and anticipated site conditions. This configuration is widely used for identifying fractures and other
discontinuities in bedrock.
ERi data will be collected using an Advanced Geosciences, Inc. (AGI) Super Sting Model R81P resistivity
meter with a maximum of 56 electrodes or similar. This multi-electrode resistivity meter allows for a
relatively high signal-to-noise ratio, which results in better data quality than older versions of the AGI Sting
system. The AGI Super Sting Model R81P allows for the automatic data collection of up to eight
simultaneous readings using an 8-channel system switchbox, resulting in increased speed of data
collection as well as improved data quality.
The ERi data will be collected along 19 transect lines as shown on Figure 7. The total length of these
transects is approximately 12,520 linear feet. Individual transect lengths will generally vary between
approximately 550 feet and approximately 1,100 feet. Data will be collected with a uniform electrode
spacing of either approximately 10 feet or approximately 15 feet, depending on the results of preliminary in-
field testing and physical site constraints.
Where ERi and seismic transects are co-located, the ERi transects will be positioned to match, as closely
as possible, the locations of the seismic transects. Final placement of the ERi transects may differ from the
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
locations shown on the survey plan based on encountered limitations associated with property access or
unanticipated physical constraints.
3.2.2.5 Geophysics Survey Transect Mapping
A backpack-mounted Global Positioning System (GPS) receiver will be used to record the location,
wherever possible, of each seismic and ERi transect line. The GPS receiver will likely not be able to be
used in dense woods or other portions of the Site that may exhibit poor GPS satellite coverage. In these
areas, transect lines will be flagged and located using traditional survey methods. Relative ground surface
elevations will be recorded along the seismic and ERi transect lines during the surveys using a laser level,
a hand level, or a surveyor's level. Transect line elevations will be tied to permanent site features shown
on the existing base map. True elevations will be established at the ends and midpoint of each transect,
and the seismic and ERi relative elevations will be converted and presented as true elevations.
The seismic refraction data will be analyzed using the Seislmager computer program, developed by
Geometrics. The program is used to correct survey geometry errors, select first arrival times of the direct
and refracted P-waves, enter elevation data, and make subsurface layer assignments prior to inputting the
data into the program's forward modeling subroutine. The results of the models are subsequently exported
to the contouring package Surfer, developed by Golden Software ..
ERi data will be processed using the Earthlmager 2D program, developed by AGI. Pre-processing involves
filtering and editing the data, as necessary and importing elevation data. The edited data are subsequently
input into the Earthlmager 2D inversion routine to produce a two-dimensional resistivity model of the
subsurface.
3.2.2.6 Reporting
The geophysical survey will be performed in two phases. The Phase 1 geophysical survey will encompass
the area located north of railroad right-of-way that separates the Burlington Industries Property from the
FCX property. Phase 2 will encompass the areas south of the railroad right-of-way. Results of Phase 1
and Phase 2 will be summarized in technical memoranda completed after each phase of the investigation.
Each memorandum will describe the geophysical survey methods, field investigation program, and results
of the fieldwork. Color-enhanced two-dimensional cross-sections will be included as attachments along
with an updated bedrock surface elevation contour map. The locations of interpreted fractures will be
shown on the cross-sections and on a separate figure in plan view. The locations of relevant site features
URS Corporation 3-9 April 28, 2009
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FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
will be annotated along the ground surface of each cross-section to assist in the siting of monitoring
wells/borings along fracture zones and/or low spots in the bedrock surfaces. The data presented in each
memorandum will be used to facilitate the siting of new monitoring wells to delineate the plume.
The results of the seismic reflection survey will be presented in a separate report prepared by the
subcontractor selected to perform the survey. These data will be incorporated into the assessment of
bedrock topography, stratigraphy, and potential fracture zones described in the technical memoranda.
3.2.3 Membrane Interface Probe (MIP) Investigation
An investigation will be completed using direct push technology (DPT) to advance a cone penetrometer
(CPT) and a MIP at approximately 29 locations north of the Burlington Industries Site.
3.2.3.1 Approach
The purpose of this screening level investigation will be to help define the downgradient extent of the
CVOC groundwater plume in saprolite and, depending upon the depths achieved by the CPT, the transition
zone. This information will be used to assist in determining the appropriate number and locations of
monitoring wells to define the,downgradient extent of the CVOC plume.
3.2.3.2 Methodology
The MIP technology uses a heated probe with a permeable membrane to measure relative concentrations
of volatile organic compounds (VOCs) in soil and groundwater. Heat from the probe causes VOCs in the
soil and groundwater to diffuse across the membrane into a carrier gas that circulates directly behind the
membrane. VOCs partitioning into the carrier gas are subsequently transported through a trunk line to gas-
phase detectors at the ground surface for detection and quantification as an electrical signal that is
quantified in microvolts (µV). The MIP probe can detect the presence of VOCs using three different gas-
phase detectors: a flame ionization detector (FID), a photoionization detector (PIO) and an electron capture
detector (ECO). Each detector, while capable of detecting a wide range of VOCs, is more sensitive to
specific groups of compounds. The ECO is the most sensitive detector for CVOCs (e.g., PCE), which is
consistent with previous MIP work performed at the Site. Therefore, the ECO results will be most heavily
relied upon with respect to assessing downgradient impacts related to the Site.
During a previous MIP investigation, depths greater than 50 feet bgs were achieved near the building using
a Geoprobe®. Greater depths could potentially be achieved using the more powerful CPT rigs operated by
FUGRO, which are planned for use for this investigation. It should be noted, however, that the depth to
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
which the MIP can be advanced is dependent on geology and the durability of the MIP probe (i.e., how
much down pressure can be applied to the MIP probe without damaging the probe, note that this is
somewhat dependent upon the experience of the operator). These factors will ultimately determine the
penetration depths achieved at a given location.
The rate of MIP/CPT advancement at each location will be dependent upon the presence and magnitude of
contamination. To obtain a representative in-situ measurement of VOCs, the MIP probe must remain still at
the depth interval where contamination is detected for a sufficient period of time to allow the carrier gas to
return from the MIP probe to the detectors at the ground surface (i.e., typically on the order of 35 to 40
seconds for a depth of 100 feet or less). Efforts will be made to expedite the advancement of the MIP
through the vadose zone (which has not been directly impacted by site releases in the MIP/CPT exploration
areas) by minimizing stops to approximately every 5 to 10 feet above the water table and focusing stops at
smaller intervals of every 4 to 5 feet in the saturated zone or more frequently, as deemed necessary, where
impacts are detected.
In order to help define the extent of the groundwater plume, MIP/CPT explorations are proposed in the
following areas:
• Eight locations (i.e., locations MIP-1 through MIP-8) along Wendover Road;
• Two locations (i.e., locations MIP-9 and MIP-10) located along Waverly Place;
• Eight locations (i.e., locations MIP-11 through MIP-18) west of ldlewile Drive; and
• Eleven locations (i.e., locations MIP-19 through MIP-29) along Gregory Road.
These proposed MIP/CPT explorations are shown on Figure 8. Final locations will be dependent upon
gaining access to the properties on which the explorations are proposed and accessibility on the property
itself.
MIP logs provide an indication of relative concentrations of dissolved CVOCs with depth. During previous
MIP work completed at the Site, the MIP detected zones of impacted groundwater exhibiting dissolved
concentrations of PCE ranging from approximately 20 micrograms per liter (µg/L) to more than 21,000 µg/L
based upon a comparison to vertically stratified groundwater samples collected using passive diffusive bag
samplers (PDBS), as indicated below.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Sile (OU3)
Statesville, North Carolina
PCE Concentration in Passivo Diffusive Bag Samples From Selocted N•1 Wells
versus MIP Response
MIP ResponH (uv)
Similar trends were identified for confirmatory groundwater grab samples collected with the Geoprobe® at
previous MIP locations but the data showed a greater degree of scatter, and generally lower CVOC
concentrations than would be anticipated based upon the MIP response. These variations are potentially
due to bias introduced from sediment entrainment, which is common with groundwater sampling performed
with a Geoprobe®. Based upon the relationship indicated above, a response of approximately 2 x 105
microvolts (uv) or less will be considered indicative of approximate limits of CVOC impacts in groundwater.
In addition to the MIP, the CPT will provide tip resistance, sleeve resistance, and pore pressure data to help
assess stratigraphy and water level with depth. Pore pressure dissipation testing will also be performed
with the CPT at selected intervals below the water table, in a subset of exploration locations, to estimate
horizontal hydraulic conductivity of the soils penetrated by the CPT. Zones selected for pore pressure
dissipation testing will be based upon a review of real time pore pressures, MIP results, and tip resistance
data during advancement of the MIP/CPT.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
Upon completion of each push, the subcontractor will backfill the completed MIP/CPT holes to the ground
surface using a cement-bentonite grout slurry or similar sealing material. As needed, the sensory portion of
the MIP will be cleaned between explorations.
Prior to each working day, the instrument will be tuned and calibrated by the subcontractor according to the
manufacturer's recommendations. The trip time will be calibrated using a PCE standard each day. In order
to confirm the sensitivity of the MIP used for this investigation, the probe will be advanced at a previous
MIP location and to the same depth as the original exploration to confirm a similar response in known
contaminated zones.
It should be noted that the MIP investigation will not eliminate the need for monitoring wells to delineate the
downgradient extent of the plume. Rather, the MIP is a screening tool to provide a scientific basis for
identifying monitoring locations and helping to identify appropriate screen intervals for monitoring wells
installed to delineate the downgradient extent of the CVOC plume in saprolite and possibly transition zone
materials. The MIP will not provide information regarding impacts to bedrock and therefore, monitoring
wells will be installed to define the downgradient extent of impacts in fractured bedrock, with the placement
of these wells guided by results of the geophysical investigations described in Section 3.2.2.
Upon completing the MIP/CPT investigation, data will be presented in a report from the subcontractor that
includes a description of the investigation, specific data collected during the investigation, methods and
specifications of equipment used to collect the data, a map showing the locations of MIP/CPT explorations,
and graphical presentation of the results in two and three-dimensional views. MIP logs showing ECD, PID,
and FID responses with depth and CPT logs showing changes of tip resistance, sleeve resistance, and
pore pressure with depth will be provided as an attachment along with supporting data and computations of
hydraulic conductivity from pore dissipation tests. These data will be reviewed by the EPNG Statesville
technical team and used to identify downgradient well locations and screen intervals at locations A, D, H
and I (see Section 3.3.1), to define the downgradient vertical and horizontal extent of impacts in saprolite
and the transition zone, to the extent permitted by the data.
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FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
3.3 Supplemental Monitoring Wells, Hydraulic Testing and Mass
Flux Estimates
Supplemental monitoring wells will be installed in the saprolite, transition zone, and in the shallow and
deeper fractured bedrock based upon a consideration of the following:
• the findings of the CSM;
• groundwater analytical data collected from the existing monitoring well network;
• groundwater equipotential data;
• results of the seismic and ERi surveys described in Section 3.2.2; and/or
• results of the MIP investigation described in Section 3.2.3.
These wells will be installed to:
• Provide groundwater analytical data to refine the delineation of the vertical and lateral extent of the
CVOC plume originating from the Site;
• Provide water level information to characterize the groundwater flow field in saprolite, transition
zone material and fractured bedrock downgradient of the CVOC source area;
• Provide supplemental monitoring locations to help quantify the horizontal mass flux from the source
area; and
• Provide water level observations during pumping tests proposed in saprolite, transition zone, and
fractured bedrock to estimate hydraulic properties and evaluate anisotropy in these units. Slug
tests performed at monitoring wells used to delineate the lateral and horizontal extent of impacts
will be used to provide additional information regarding the distribution of hydraulic conductivities.
These data will facilitate the development of a predictive groundwater fate and transport model
referenced earlier and discussed in a separate work plan. The model will be used to predict
timeframe for the current remedy or alternative approaches to meet cleanup goals established in
the ROD.
It should be noted that the remainder of this section discusses only those supplemental wells, which will be
installed and used to delineate the plume. New monitoring wells proposed to support pumping tests in
saprolite, transition zone material, and fractured bedrock as well as measurements of mass flux are
described later in Sections 3.3.4 and 3.3.5, respectively. The approximate drilling locations for the
proposed wells are shown on Figure 9. Final drilling locations will be determined (and may be adjusted)
pending results of the geophysical survey and MIP investigation. The wells proposed for plume delineation
assume that the current understanding of bedrock topography does not significantly change with the
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FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
acquisition of new data proposed as part of this work plan. Table 3 presents details of the proposed well
installation program including:
• generalized locations;
• purpose and rationale for the monitoring wells at each location;
• geologic units to be monitored at each location;
• basis for selection of the screen intervals at each location; and
• .intended use of monitoring wells at each location.
Table 4 summarizes the anticipated depths, drilling methodology, well diameter, screen slot size, and
screen intervals for proposed supplemental well locations based upon an interpretation of hydrogeology,
depth to fractured bedrock, and inferred depth of impacts using existing site data presented in the CSM. It
should be noted that both Table 3 and Table 4 include information for wells installed to support pumping
tests and mass flux estimates described later in this work plan. The depths and screened intervals for
proposed monitoring wells are subject to adjustment pending conditions observed during drilling (e.g.,
fractures in core samples and water yield/loss), results of packer testing (Section 3.3.3.3), and borehole
geophysical logging (Section 3.3.2) at specific locations.
3.3.1 Supplemental Plume Delineation/Stability Assessment Wells
3.3.1.1 Approach/Location Rationale
Based upon a review of previous investigations, it appears that the vast majority of the monitoring wells
installed following the completion of the RI have been sited either along or tangential to the axis of the
plume or near the primary CVOC source areas identified in the CSM. For this reason, and since historical
wastewater disposal to sewer lines along Phoenix Street and Yadkin Streets may have been a secondary
source of impact to groundwater, the lateral extent of groundwater impacts in the Northern and Southern
CVOC Plume is not well delineated. In addition, the CSM that has been developed for the Site using
available data collected since the completion of the RI suggests that groundwater flow from the northern
end of the Burlington Industries Building may not be directly to the north as previously thought. Rather,
groundwater flow in this area appears to be in a more northwesterly direction, potentially controlled by the
topography of bedrock and possibly a northwest/southeast trending fracture zone. As a consequence, the
wells located furthest downgradient from the north side of the source area (i.e., W-31s/i) may actually be
located near the eastern lateral margin of the Northern Plume. Therefore, EPNG believes that the extent of
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FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
the Northern CVOC Plume should be further delineated in order to verify that potential receptors have been
identified and are not adversely affected by impacted groundwater. On this basis, EPNG is proposing to
advance soil borings and install supplemental groundwater monitoring wells at the following locations,
which are identified on Figure 9. The proposed well locations are based upon the distribution of CVOCs in
groundwater determined from a comprehensive set of groundwater analytical data and the current
understanding of the locations of source areas and groundwater flow.
Location A: A near-field well cluster will be completed in the inferred core of the CVOC plume at
the northern end of the property owned by EPNG. The final location of this well cluster will be
determined based upon the presence of geological anomalies, if any, identified as part of the
geophysical investigation described in Section 3.2.2. The well cluster will be located to coincide
with geophysical anomalies, if identified, which potentially are indicative of fracture zones. This
well cluster will include a well screened in shallow saprolite, one in deeper saprolite, one in the
transition zone, and two or more wells screened in fractured bedrock. The purpose of this
monitoring well cluster is to define the vertical limits and concentration distribution in the core of the
plume, the location of the core of the plume, and to assess concentrations of PCE and its daughter
compounds in potentially significant fracture zones controlling the migration of CVOCs in bedrock
groundwater. In order to guide decisions regarding the placement of screen intervals in bedrock,
EPNG plans to log the bedrock borehole at Location A using the following geophysical methods:
caliper, fluid conductivity, resistivity, temperature, and acoustic televiewer to identify water-bearing
fractures. These data will be used to identify zones for packer testing and selecting monitoring
intervals in bedrock. If multiple water-bearing fractures (i.e., more than two intervals) are identified
from the geophysical logging, a West Bay® multilevel well system will be installed in bedrock at this
location. Otherwise, bedrock monitoring wells will likely be installed using conventional polyvinyl
chloride (PVC) materials in separate adjacent bedrock borings. The borehole(s) for the bedrock
monitoring wells will be completed using either rotosonic methods or an air hammer. It should be
noted that existing data suggests that elevated concentrations of dissolved CVOCs have migrated
along the bedrock surface from the primary source area towards Location A. In order to minimize
the potential for vertical movement of high concentrations of CVOCs from the transition zone into
fractured bedrock via the bedrock borehole, a temporary oversized steel casing will be installed
and sealed in competent bedrock at this location prior to completing the bedrock borehole(s). The
bottom of the casing will be advanced into a one to two foot deep socket drilled into the bedrock.
Prior to advancing the casing, the socket will be filled with bentonite grout to a level of two to three
feet above the bedrock surface. The casing will then be advanced through these sealing materials
to the bottom of the socket. Before completing the bedrock borehole, the sealing materials will be
allowed to hydrate for approximately 12 hours or longer. Overburden monitoring wells at Location
A will be completed using hollow-stem augers, case and wash .drilling methods (as needed
depending upon depth and drilling difficulty) or rotosonic methods. Screen intervals for the
saprolite and transition zone monitoring wells will be completed based upon soil field screening
results using an FID or PIO and Color-Tee® colorimetric tubes for PCE as well as grain-size
distribution and other observations from soil samples retrieved during drilling. Additional
information on drilling methods is provided in Section 3.3.1.2.
Location B: A well cluster is proposed along the east side of Phoenix Street between the
intersections with Reid and Melviney Streets in order to define the eastern extent of the Northern
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FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
CVOC Plume and provide a monitoring point to confirm the stability of the lateral extent of the east
side of the Northern Plume. Four monitoring wells are proposed at this well cluster: one screened
in shallow saprolite, one in deeper saprolite, one in the transition zone, and one in shallow
fractured bedrock. Wells at this location will be installed using hollow-stem augers, case and wash
methods, as needed, or rotosonic Methods and coring with an H-sized core barrel (bedrock well).
The screen interval for the shallow bedrock well will be based upon a combination of observations
of fractures in the rock core, packer test results, and screening groundwater samples collected
from identified fracture zones during packer testing and analyzed using Color-Tee® colorimetric
tubes for PCE. Similarly, screen intervals for the saprolite and transition zone monitoring wells will
be completed based upon soil field screening results using an FID or PIO and Color-Tee®
colorimetric tubes for PCE as well as grain-size distribution and other observations from soil
samples retrieved during drilling. Well cluster Location B has been sited in an area that is
interpreted to be outside of the lateral extent of the CVOC groundwater plume based upon existing
data. If groundwater samples collected from the wells are found to contain PCE or its daughter
compounds above the cleanup criteria presented in the ROD and ESD, additional wells may be
warranted further to the east/northeast to define the lateral extent of the Northern CVOC Plume.
Location C: A well cluster is proposed northwest of the Site and west of Waverly Place in the
Statesville Business Park to define the western extent of the Northern CVOC Plume and provide a
monitoring point to confirm the stability of the lateral extent of the west side of the Northern Plume.
As at Location B, four monitoring wells are proposed at this well cluster: one screened in shallow
saprolite, one in deeper saprolite, one in the transition zone, and one in shallow fractured bedrock.
Wells drilled at this well cluster location and screen intervals for individual wells will be selected
using the same methods employed at Location B. Well cluster Location C has been sited in an
area that is interpreted to be outside of the lateral extent of the CVOC groundwater plume based
upon existing data. If groundwater samples collected from the wells are found to contain PCE or
its daughter compounds above the cleanup criteria presented in the ROD and ESD, additional
wells may be warranted further to the west/northwest to define the lateral extent of the Northern
CVOC Plume.
Location D: A far-field well cluster is proposed just northwest of the intersection of Wendover
Road and Waverly Place. As with Location A, the final location of this well cluster will be
determined based upon the presence of geological anomalies, if any, identified as part of the
geophysical investigation described in Section 3.2.2, as well as from results of the MIP
investigation described in Section 3.2.3. The well cluster will be located to coincide with
geophysical anomalies, if identified, that potentially are indicative of fracture zones and at a
location downgradient of potentially impacted groundwater identified using the MIP. This well -
cluster will include a well screened in shallow saprolite, one in deeper saprolite, one in the
transition zone, and two or more wells screened in fractured bedrock. The purpose of this
monitoring well cluster is to define the downgradient extent of the Northern CVOC Plume. In order
to guide decisions regarding the placement of screen intervals in bedrock, EPNG plans to log the
bedrock borehole at Location D using the following geophysical methods: caliper, fluid conductivity,
temperature, and acoustic televiewer to identify water-bearing fractures. These data will be used
to identify zones for packer testing and selecting monitoring intervals in bedrock. If multiple water-
bearing fractures (i.e., more than two) are identified from the geophysical logging, a West Bay®
multilevel well system will be installed in bedrock. Otherwise, bedrock monitoring wells will likely
be installed using conventional polyvinyl chloride (PVC) materials in separate adjacent bedrock
borings. Overburden monitoring wells at Location D will be completed using hollow-stem augers,
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the case and wash method (as needed}, or rotosonic methods. Screen intervals for the saprolite
and transition zone monitoring wells will be completed based upon soil field screening results using
an FID or PID and Color-Tee® colorimetric tubes for PCE as well as grain-size distribution and
other observations from soil samples retrieved during drilling. The borehole(s) for the bedrock
monitoring wells will be completed using either rotosonic methods or an air hammer.
Locations E and F: The downgradient extent of the CVOC plume located to the south of the Site
(i.e., the Southern CVOC Plume) has been defined in saprolite and bedrock, as has the lateral
limits of this plume in the saprolite (but not in bedrock). The concentration of PCE detected in
groundwater from the transition zone in the Southern CVOC Plume near the source areas beneath
the Burlington Industries Property (i.e., at well W-41t) is low (i.e., approximately 6 µg/L and much
lower than PCE concentrations in either saprolite or bedrock in the vicinity of this location) and
daughter products have not been detected at this well. Consequently, it appears that the Southern
CVOC Plume in the transition zone may not extend beyond the downgradient extent of the South
CVOC Plume identified in saprolite or shallow bedrock. The lateral extent of the Southern CVOC
Plume in the transition zone and bedrock are not well defined. On this basis, two well couplets,
each consisting of a well screened in the transition zone immediately above shallow competent
bedrock and a well screened within shallow bedrock, will be installed to provide data to better
delineate the lateral limits of CVOC impacts in these units. The well couplet at Location E has
been sited along Woodlawn Drive and the well couplet at Location F has been sited near the
intersection of West Front Street with Hickory Highway/Newton Drive. The wells will be installed
using a combination of hollow-stem augers, case and wash methods (as needed), or rotosonic
methods and coring using an H-size core barrel (bedrock wells}. The screen interval for the
shallow bedrock wells at these well couplets will be based upon a combination of observations of
fractures in the rock cores, packer test results, and screening groundwater samples collected
during packer testing from identified fracture zones using Color-Tee® colorimetric tubes for PCE.
Screen intervals for the transition zone wells will be based upon soil screening measurements
made using an FID or PID and Color-Tee® colorimetric tubes for PCE. Locations E and F have
been sited in an area that is interpreted to be outside of the lateral extent of the CVOC
groundwater plume based upon existing data. If groundwater samples collected from the wells are
found to contain PCE or its daughter compounds above the cleanup criteria presented in the ROD
and ESD, additional wells may be warranted further to the east and west to define the lateral extent
of the Southern CVOC Plume.
Location G: Based upon information presented in the CSM, historical pumping of an industrial
supply well located at the former Carnation Building west of the Site appears to have caused
spreading of groundwater impacted with CVOCs towards the well. That well is now inactive and no
longer affecting OU3. Results of an environmental database search identified another bedrock
well, with a yield of 15 gallons per minute, to the east of the Burlington Industries Building near
Piedmont Street. The status and potential effect of this well, if any, on impacted groundwater at
OU3 is not known. In order to assess if this well induced impacted groundwater to move east of
the Site, a monitoring well will be installed in shallow bedrock at Location G east of the Burlington
Industries Building and adjacent to the north side of Piedmont Street. The boring for the well will be
completed using hollow-stem augers, case and wash methods (as needed), or rotosonic methods
and coring using an H-size core barrel. The screen interval for the shallow bedrock well at this
location will be based upon a combination of observations of fractures in the rock cores, packer
test results, and screening groundwater samples collected during packer testing from identified
fracture zones using Color-Tee® colorimetric tubes for PCE.
URS Corporation 3-18 April 28, 2009
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
Locations H and I (if needed): In the event that groundwater analytical results indicate that the
Northern CVOC Plume extends beyond well cluster Location D, additional wells may be needed to
define the downgradient extent of the Northern CVOC Plume in saprolite, the transition zone,
and/or fractured bedrock. In the absence of impacts at well Location D, a piezometer nest will be
installed at one of these two locations to provide water level data to support the development of a
predictive groundwater fate and transport model described earlier. It is anticipated that the bedrock
explorations for these locations would be completed to a depth corresponding to the bottom of the
quarry located north of Interstate 40 using rotosonic or air-rotary drilling methods. Upon
completion, the bedrock borehole(s) will be evaluated for water-bearing fractures using the
following borehole geophysical methods: caliper, fluid conductivity, temperature, and resistivity.
Depending upon the uniformity of the borehole, the boring may also be logged using an acoustic
televiewer. After geophysical logging, packer testing will be conducted to assess the hydraulic
properties of the bedrock and a Westbay® Multilevel Well System or an equivalent system will be
installed in the borehole(s) with screen intervals at each significant water-bearing fracture zone.
Wells installed in saprolite and transition zone materials will be completed using rotosonic, hollow-
stem augers, or case and wash methods and wells will be constructed of conventional PVC well
materials to allow for adequate development and hydraulic testing of these materials The screen
intervals for saprolite and transition zone wells at these locations will be assessed based upon
observations of soil stratigraphy and soil screening results performed using an FID or PIO and
Color-Tee® colorimetric tubes for PCE.
3.3.1.2 Drilling and Well Installation -Methodology
As noted above and in Table 4, it is anticipated that monitoring wells will be installed using a combination of
several different drilling methods depending upon the information to be collected from the monitoring well.
The drilling methods to be used to install the wells proposed in this work plan include hollow-stem augers,
case and wash methods, coring with and H-size core barrel, rotosonic, and air hammering (i.e., air-rotary)
methods .
During drilling at plume delineation well locations described above and where stratigraphic information is
needed to select well screen intervals (e.g., at the proposed saprolite/transition zone pumping test
location), soil samples will be collected from a single boring that extends to bedrock.2 The samples will be
collected at five-foot intervals in the unsaturated zone and then continuously through the saturated portion
of the saprolite and transition zone to the unweathered bedrock surface. The samples will be collected
using either a two or three-inch diameter steel split-spoon sampler that is decontaminated prior to use and
2 At drilling locations for the pumping test, samples will be collected continuously to bedrock at one location for the
saprolite/transition zone pumping test and at one location for the bedrock pumping test and at five-foot intervals below the water
table at the remaining locations for lithologic classification. In the case of the pumping test performed for saprolite and transition
zones where observation wells are co-located, soil sampling shall not be duplicated (i.e., samples will be obtained from the
boring penetrating the transition zone but not from the boring drilled for the well to be completed in the saprolite).
URS Corporation 3-19 April 28, 2009
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
after each sample interval using a solution of laboratory-grade detergent (e.g., Alconox® or Liquinox®)
followed by a rinse with potable water or a rotosonic core barrel where rotosonic methods are used.
Following collection, each sample will be visually classified according to color, density, grain-size
distribution, and moisture content according to the Unified Soil Classification System (USCS). Care will be
taken to identify zones or layers exhibiting differences in grain-size distribution or color in the overall
sample matrix. These data will be recorded on field soil boring log forms along with sample recovery, blow
counts (as applicable), the type of drilling and sampling equipment, drilling tool diameter, borehole
diameter, depth to groundwater, and field screening information. After logging the sample, a portion of the
sample will be placed in a glass jar covered with aluminum foil or in a plastic Ziploc® bag for screening
using an FID or a PID equipped with a 10.2 electron volt or higher intensity lamp. Where rotosonic
methods are used, each soil core will be divided into 2-foot sections and a sample from each section will be
retrieved for screening. If layering of soils exhibiting different grain-size is noted in a recovered soil sample,
then separate samples representative of each layer will be collected for screening using the FID or PID. In
the event that a positive result above background is measured, the soil samples from that location will be
further screened for CVOCs using a Color-Tee® colorimetric tube for PCE. If the FID does not identify a
response above background conditions in soil at a particular boring location, a minimum of two soil samples
from that location will be screened using the Color-Tee® Method, one from the saprolite and one from the
transition zone above the bedrock surface. Screening results will be recorded on the soil boring logs and
used to help select monitoring well screen intervals in the saprolite and transition zone. At locations where
bedrock is cored, coring will be performed using the wire-line method equipped with a triple tube core barrel
(or alternatively as double core barrel), pending local availability. Each section of core will be marked from
top to bottom using a paint marker or a permanent marker with the top and bottom of the interval
designated as "T" and "B" Cores will be logged for percent recovery, the depth interval of the core, t_he
depth and dip of individual fractures, the degree of weathering of fracture surfaces, rock type and
mineralogy, and Rock Quality Designation (ROD). ROD is defined as the total length of core sections over
4 inches in length divided by the total length of the core expressed as a percentage. In addition, the rate of
advancement of the core barrel and water loss (if any) will be noted for each core interval. These data will
be used to develop rock core logs for each core location ..
At locations B, C, E, F, and G, groundwater samples will be collected from fracture zones identified from
bedrock cores during borehole advancement, using a packer assembly equipped with a submersible pump.
URS Corporation 3-20 April 28, 2009
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
A minimum of five borehole volumes isolated by the packer system will be removed prior to sampling, after
which a groundwater sample will be collected from the discharge line of the pump. The groundwater
sample will then be screened for the presence of PCE using a Color-Tee® colorimetric tube in accordance
with the Standard Operating Procedure (SOP) published by the manufacturer. These data will be recorded
on the boring logs and used in combination with packer test results to select the screen interval for the
bedrock monitoring wells.
Upon completion of the drilling, and where applicable borehole geophysics (Section 3.3.2) and packer
testing (Section 3.3.3.3), two-inch diameter monitoring wells will be constructed in the boreholes. With the
exception of bedrock monitoring wells at Locations A and D, along with Locations H and I (if installed), wells
will be constructed of Schedule 40 polyvinyl chloride (PVC) materials, each equipped with a five to ten-foot
section of factory-slotted No. 10 or 20 (0.010 to 0.020 inch slots) well screen with flush joints. It is
anticipated that multiple water-bearing fractures will be identified at Locations A and D as well as at
Locations H and I (if installed). For this reason and since the purpose of these well clusters is to define the
vertical and downgradient extent of the Northern CVOC Plume, EPNG plans to install Westbay Multilevel
Well Systems or an equivalent system in bedrock at Locations A and D, and potentially at H and I. The
Westbay System (or equivalent) will allow for monitoring of multiple fractures zones in bedrock in a single
borehole, thereby reducing drilling costs and minimizing generation of investigation-derived waste, which
will require disposal. Appropriately sized sandpacks will be placed in the annulus around the well screens
and extended approximately 1 to 2 feet above the top of the screen. The remainder of the annulus above
the sandpack will be sealed with a minimum two-foot thick bentonite seal followed by cemenVbentonite
grout. Each well will be completed with a locking steel protective casing or flush-mounted gate box set in
concrete. Conventional PVC wells will be developed by surging and purging to restore, to the extent
practicable, the permeability of the formation adjacent to the well screen. At a minimum, five well screen
volumes will be removed from each well (including Westbay® discrete sample zones) and development will
continue until the discharge water is visually free of settleable solids or ten screen volumes have been
removed, whichever occurs first. Well development water will be containerized and disposed of off-site by
a licensed disposal contractor. Well construction and development information will be recorded on well
completion logs.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
All downhole drilling and testing equipment will be steam cleaned or power washed prior to use and
between drilling locations at a central decontamination area that has been previously established at the Site
near the boiler house. Splitspoons will be cleaned between samples using a wash with dilute Alconox® or
Liquinox® solution followed by a rinse with potable water. The decontamination activities will be performed
to limit the potential transfer of constituents of interest between drilling locations, which is vital since the
goal of the perimeter plume delineation wells is to establish the absence of CVOCs even at low levels.
Decontamination fluids generated from cleaning drilling equipment will be collected and managed through
off-site disposal with a licensed disposal contractor. Other investigation-derived wastes associated with
drilling activities will include drill cuttings, development water, and spent personal protective equipment
(PPE). Decontamination fluids, development water, and drill cuttings will be containerized in 55-gallon
Department of Transportation (DOT) rated drums, and tested to assess the appropriate method of disposal.
Drummed cuttings and development water will be transported and temporarily staged on-site near the
boiler house with spent PPE and decontamination fluids pending disposal. URS will assist EPNG as an
agent in preparing manifests, identifying disposal facilities and coordinating the removal and disposal of
residuals.
3.3.2 Borehole Geophysics
URS will perform geophysical logging in the deepest bedrock borings completed at locations A, D, H (if
installed), I (if installed), and at wells W-61i and W-85i installed to support mass flux measurements
described later in Section 3.3.5 .
3.3.2.1 Approach
The purpose of conducting borehole geophysics at the described locations is to identify the vertical
locations of water-bearing fractures in order to assist in selecting screen intervals for bedrock monitoring
wells used to assess the vertical extent of the CVOC plume.
URS will likely perform caliper, fluid temperature, fluid conductivity, and normal resistivity logging in the rock
boreholes at the locations described above. The use of multiple logging tools provides added confidence in
identifying water-bearing fractures and correlating fractures with geological anomalies, if any, identified
during surface geophysical surveys.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
Depending upon the uniformity of the borehole, which will be assessed from the caliper log, the boreholes
may also be logged using an acoustic televiewer. A brief description of each geophysical method is
presented herein followed by the approach that will be used to complete the survey.
3.3.2.2 Methodology
3-Arm Caliper
In the open-hole section of a boring, this log will identify potential fractures or sections where pieces of rock
may have been plucked from the surface of the borehole wall. The log will identify features along the
borehole wall that resulted in localized changes in the borehole diameter, some of which may represent
fractures. The caliper log is run from the bottom of the well to the top. The 3-Arm Caliper alone is not
sufficient to identify water-bearing fractures.
Fluid Temperature & Conductivity
These logs will provide temperature and resistivity information for the borehole fluid, to delineate
temperature and resistivity gradients within the well. Relatively localized spikes in temperature or resistivity
may indicate the presence of water-bearing zones, whereas uniform gradients may be more indicative of
ambient conditions. Fluctuations in gradients may be indicative of mixing zones.
Fluid conductivity is obtained directly from the fluid resistivity log as the inverse of resistivity. Generally,
temperature is recorded down the well and fluid resistivity (conductivity) recorded up the well as these logs
can be run from a single tool.
16-inch Normal Resistivity
The 16-inch normal resistivity log measures formation resistivity, The 16-inch designation refers to the
electrode separation within the tool, where the greater the separation, the greater the zone of investigation
into the formation from the borehole. This log can only be run in the open-hole portion of the well because
casing will prevent accurate measurements.
The formation resistivity log is useful for locating water-bearing zones. Porous media characterized by
increased pore water content, typically exhibit lower resistivity than less porous, or impermeable, geologic
media. The utility of the formation resistivity log is dependent upon the water-bearing fractures
representing a discernable resistivity contrast compared to the unfractured bedrock.
URS Corporation 3-23 April 28, 2009
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Acoustic Televiewer
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
The acoustic televiewer utilizes a fixed acoustic transducer and a rotating acoustic mirror capable of focusing
the acoustic signal in large-diameter boreholes or relatively turbid water. Data are corrected to magnetic north
through use of a series of magnetometers and accelerometers. These corrections enable fracture orientation
to be determined, and thus correlated with geophysical anomalies identified with surface geophysics, which
may represent larger scale fracture zones in bedrock.
The acoustic televiewer provides high-resolution acoustic amplitude and travel time data in order to
characterize features in boreholes such as solution openings and fractures. The acoustic elements and
impedance are matched to the borehole fluid in order to provide optimum reflected amplitude and high-
resolution images.
The acoustic televiewer cannot be run in dry conditions because water is required to transmit the acoustic
signal. The acoustic televiewer cannot be run inside casing because it will interfere with transmission of the
signal into the formation. No other logs can be collected simultaneously with the acoustic televiewer.
Survey Sequence
URS anticipates the borehole logging in the following sequence:
• Temperature;
• Fluid Conductivity;
• Resistivity;
• 3-Arm Caliper; and
• Acoustical Televiewer (depending upon the smoothness of the borehole).
Only the open-hole section below the groundwater level will be logged during the survey. Guidance will be
provided by project representatives regarding proper decontamination procedures for the geophysical
logging tools prior to mobilization to the Site and between borehole locations. At a minimum, the downhole
equipment will be washed with distilled water prior to use and between survey locations.
Final geophysical logging data will be processed using the software WellCad, issued by Advanced Logic
Technology (ALT). After processing, the results of the geophysical logging will be reviewed to select well
screen intervals in bedrock at each of the logged locations. Results of the borehole geophysics will be
provided in a technical memorandum with geophysical logs provided as an attachment.
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3.3.3 Hydraulic Testing -Single Well Tests
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
Data concerning the hydraulic properties of the groundwater systems at the Site are sparse and there are
currently no reliable estimates of the hydraulic properties of fractured bedrock.
3.3.3.1 Approach
One of two types of single-well hydraulic testing will be performed on each newly installed monitoring well
and rock borehole as well as on a subset of existing wells to obtain estimates of the hydraulic properties
(i.e., transmissivity, hydraulic conductivity and/or storativity) of the saprolite, transition zone, and the
fractured bedrock. These single-well hydraulic tests will include slug tests and packer tests. The hydraulic
properties data obtained from these tests will be used to develop a predictive numerical groundwater fate
and transport model for the Site, which is described in a separate work plan (URS, 2009). The model will
be used to help forecast the performance of the existing remedy or alternative technologies in achieving the
established cleanup objectives.
3.3.3.2 Methodology -Slug Tests
Slug tests will be performed in up to 40 existing wells and in newly-installed monitoring wells screened in
the saprolite and transition zone material. Wells selected for slug tests will be based upon a consideration
of the plume location, geophysical data, and results of the MIP survey to provide data across the lateral
area and vertical extent of the plume. Existing wells that will potentially be considered for testing are
summarized in Table 5.
Saprolite Wells
MP-1
MP-3
MP-4
MP-7
W-1s
URS Corporation
Table 5
Existing Monitoring Wells Considered for Slug Testing
FCX Statesville Superfund Site
Statesville, North Carolina
Transition Zone Wells Shallow Bedrock Wells 'DeE!per:Sedrock Wells .. _.,,
MW-10 W-1i W-20d
W-211 W-2i W-28d
W-34t W-5i W-33d
W-36t W-10i
W-38t W-13i
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Saprolite Wells Transition Zone Wells
W-2s
W-5s
W-8s
MW-9
W-10s
W-15s
W-16s
W-18s
W-20s
W-21s
W-24s
W-31s
W-36s
W-38s
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
Shallow Bedrock Wells Deeper Bedrock Wells
W-15i
W-16i
W-20i
W-26i
W-28i
W-29i
W-30i
W-31i
W-32i
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It is recognized that wells that are installed in fine-grained soils and are not sufficiently developed can be
affected by low-hydraulic conductivity dynamic well skins (Butler, 1998). A well skin is a layer of fines that
can form along the sides of the borehole a.s a result of smearing or deposition by fluids in the borehole
during the drilling process. If not removed, these fines can result in an underestimate of the hydraulic
conductivity of the water-bearing formation based upon analysis of slug test data. To minimize the potential
for interference from well skins, all newly installed monitoring wells will be developed. In order to confirm
that low-hydraulic conductivity well skins are not adversely affecting the hydraulic conductivity data in wells
completed in the saprolite and transition zone, generally three tests will be performed in each tested well as
suggested by Butler (1998). For wells screened across the water table, all three tests will be performed as
rising head slug tests. For wells screened below the water table, two of the slug tests will be performed as
rising head slug tests and the third test will be performed as a falling head test. Typically, two of the tests
will be performed at the same displacement to permit an assessment of dynamic skin effects, and the
remaining test will be performed at a different water displacement, varying by a factor of at least two from
the displacement during the other two tests, if a sufficient water column is present in the well. Two slug
tests will typically be completed at existing bedrock wells selected for testing using two different size
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
bailers. Recovery data normalized to the water level displacement at the start of each test will be plotted
with time and assessed for changes in the recovery plots to assess the presence of a well skin. Data will
be evaluated using a method described by Butler including Cooper et. al. (1967) and other appropriate
methods to provide a representative range of hydraulic conductivities of the water-bearing materials.
In general, slug tests will be performed in the following manner:
1. Prior to performing slug tests, well construction and geologic information (i.e., well diameter,
borehole diameter, screen length, total well depth, and the depth interval of the geologic unit
screened by the well) will be tabulated. To the extent practicable, readily observable well
construction information that is needed for the analysis of the slug test data (i.e., casing radius and
well depth) will be verified and recorded in a field note book and/or on a slug test data collection
form.
2. A pressure-sensitive transducer/data logger will be deployed in the well to be tested a minimum of
1 foot off the bottom of the well. The transducers used for the testing will be rated for pressures
appropriate for hydraulic heads in the monitoring wells. The transducer cable will be pre-measured
so that the amount of water above the transducer is known. The transducer will be secured at the
wellhead and the depth of the transducer in the well will be recorded in a field notebook and/or on
the data collection form.
3. For tests performed in the rising head mode, a dedicated bailer to be used to remove a slug of
water will be lowered into the well. The bailer will be a minimum of 30 inches in length. As
indicated earlier, different sized bailers or a slug of a different equivalent volume (where falling
head tests are performed) will be used for subsequent testing, as feasible, to create different
displacements during the testing. Theoretically, the different displacements should yield
comparable estimates of hydraulic conductivity. In the event that a solid cylindrical slug is
employed for testing, falling and rising head tests using the slug will be performed first followed by
a rising head test using a bailer displacing a volume of approximately 0.5 or 2 times the volume of
the solid slug. At wells where only rising head tests are performed (e.g., wells screened across the
water table), the slug tests will be performed using two different sized bailers with the first and last
test performed using the same bailer (i.e., at the same displacement).
4. Prior to removing the bailer or inserting the solid slug (in the case of falling head tests), the static
water level will be measured in the well and recorded in a field notebook or on the data collection
form.
5. The datalogger/transducer will be programmed with the test parameters.
6. Once programmed, the water level sensed by the transducer will be recorded in the field notebook.
The transducer will then be raised by a measured increment and the water level sensed by the
transducer will be rechecked to verify that the transducer and data logger are generating accurate
water level data. Theoretically, the difference in the hydraulic head should be equal to the
measured incremental change in the transducer depth. In the event that the difference between
the observed change and the measured incremental change exceeds 0.05 feet, the transducer will
be taken out of service and a new transducer that meets the above criteria will be used.
URS Corporation 3-27 April 28, 2009
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, Nor1h Carolina
7. After verifying that the transducer is providing accurate measurements of water level change, the
data logger will be activated and the bailer (or slug) will be rapidly withdrawn from/inserted into the
well.
8. When the water level has recovered approximately 90 percent or after a maximum of 60 minutes,
the test will be stopped.
9. After the test has been stopped and when the water level has recovered to within at least 80
percent of the static water level, the test will be repeated following steps 3, 7 and 8.
At the end of each day or more frequently as necessary, data will be downloaded to a laptop computer and
emailed to the data manager, and will be retained in the project file pending analysis. Results of the slug
tests will be documented in a technical memorandum describing the methods used to perform the slug
tests and analyze the data, and will present a summary of the results of the data analysis. The technical
memorandum will include graphical data plots generated by the aquifer testing software referred to as
AOTESOLV®.
3.3.3.3 Methodology -Packer Tests
Packer testing will be performed on new bedrock borings and at existing openhole bedrock monitoring wells
(e.g., IW-1 through IW-3). Testing intervals will be based upon a review of bedrock cores and/or results of
borehole geophysical logging. Packer testing is not planned over intervals that do not exhibit natural
fractures (e.g., as indicated by cores exhibiting mechanically induced fractures with high ROD). Packer
testing will typically be performed at 5 to 10 foot intervals depending upon the degree of fracturing observed
on rock cores or identified from geophysical logs. This testing will determine the horizontal hydraulic
conductivity and/or transmissivity of the tested interval. Packer testing in fractured bedrock will be
performed using the most recent version of American Standard Testing and Material (ASTM) Method
D4630-86, the method developed by the United States Bureau of Reclamation as presented by Cedegren
(1989), or an equivalent method as appropriate based upon an assessment of the method assumptions
and boundary effects. The packer tests involve installing packers above and/or below the tested interval,
injecting water under different pressures or flow rates and monitoring the water flow and/or pressure
response with time. For the ASTM Method these data are plotted on logarithmic paper and matched
against a type curve of a mathematical function G(a) versus a dimensionless numerical value (a) provided
in the ASTM Standard. Values of the water injection rate (0), time (t), G(a) and a are selected from the
curve matching and are used to solve for transmissivity (T) and Storativity (S) using the following equations:
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Where:
T = Qpg/(2nG(a)P and S = Ttiarw2
P = excess test hole pressure (Mass/Length Time2);
p = water density (Mass/Length3);
g = gravitational constant (Length/Time2); and
rw = borehole radius (Length).
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
For the method developed by the Bureau of Reclamation, the hydraulic conductivities are calculated using
the following equations:
and
where:
K = (Q/2nLh) * ln(L/r) for conditions where L?. 10r
K = (Q/2nLh) 'sinh-1(L/2r) for conditions where 10r > L?. r
K = Hydraulic conductivity (Length/Time);
Q = Constant flow rate into hole (Volume/Time);
h = Differential head from static condition during test (Length);
L = Length of the tested interval (Length);
r = Radius of the bedrock borehole (Length);
In = Natural Logarithm; and
sinh-1 = arc hyperbolic sine.
Prior to conducting the test, meters used to monitor water flow into the borehole will be verified using a
bucket and stop watch. The acceptability criteria for the meter will be a difference in average of three
consecutive measurements made with the flow meter and the bucket and stop watch of no greater than 10
percent. If this criterion is not met, the meter will be replaced with a meter that can meet this acceptance
criterion. Packer spacing will be measured prior to use in each borehole to determine the length of tested
interval. The radius of the borehole will be determined from the diameter of the core barrel when core
drilling methods are used and from caliper measurements when an air hammer is used to complete the
borehole and geophysical logging is performed to identify water-bearing fracture zones. During testing,
water levels above the packer interval will be monitored using an electronic water level meter with an
accuracy of 0.01 feet, to assess potential connections between fractures above and intersecting the tested
interval. The differential water level will be determined using the electronic water level meter. Testing data
will be recorded in a field book and on packer test data sheets. Measurements made for the packer test
calculations will be recorded in a fieldbook and/or on field data sheets. Completed data sheets and copies
URS Corporation 3-29 April 28, 2009
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
of field notes will be maintained in the project file pending analysis. Results of the packer testing will be
documented in a technical memorandum identifying the locations and methods of packer testing at
individual well locations and summarizing results of the packer testing by location and depth interval.
3.3.4 Hydraulic Testing -Pumping Tests
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and fractured bedrock including hydraulic conductivity (K), transmissivity, specific yield, and storage I coefficients.
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Pumping tests have three distinct advantages over single well hydraulic tests:
1. Pumping tests affect much larger areas than a single well test and therefore, provide
representative estimates of the average hydraulic properties of the aquifer.
2. Since pumping tests involve dewatering significant portions of the aquifer, the water level response
can provide information regarding boundary conditions within the hydrogeologic system (e.g., the
general locations of low permeability boundaries and areas of potential recharge), which may be
important in defining the fate and extent of impacted groundwater.
3. Pumping tests can help define anisotropic conditions in an aquifer that may explain the distribution
of impacts and direction of contaminant transport in groundwater systems and may confirm the
presence and orientation of fracture zones in bedrock.
Information concerning anisotropy and boundary conditions is important with respect to confirming the
CSM, evaluating the extent of impacts, and developing a predictive groundwater fate and transport model
to assess the performance of the existing or alterative remedial approaches in reaching the interim cleanup
goals. Therefore, pumping tests will be performed at wells completed in the saprolite, transition zone, and
bedrock groundwater systems. The hydraulic properties obtained from the pumping tests will be integrated
with data collected from the single well hydraulic tests to provide a representative distribution of hydraulic
properties for the development of the predictive groundwater model. Activities associated with the
proposed pumping test are summarized in the following sections.
3.3.4.2 Pumping Test Methodology -Objectives/Well Locations
In order to facilitate the pumping tests, three (3) pumping wells will be installed, one in each of the three
distinct hydrogeologic units at the Site (i.e., saprolite, transition zone, and shallow fractured bedrock). The
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
primary purpose of conducting the pumping tests will be to characterize the spatial hydraulic and storage
properties of each water-bearing zone, evaluate anisotropy and, to the extent allowable by the data, identify
boundary conditions. The collected data will be used to refine the CSM as well as provide site-specific
quantitative data needed to construct a predictive groundwater flow model referred to earlier in this work
plan. To the extent feasible, existing monitoring wells will be used as observation wells.
The pumping wells installed in the saprolite and transition zone will be constructed based upon a
consideration of the grain-size of the formation, to develop an appropriately-sized sandpack and well
screen slot size, which will help to optimize the efficiency of the well. The bedrock pumping well will be
completed with a commercially available sandpack that is appropriately sized for the slot size of the well
screen.
Boreholes will be sufficiently large to accommodate a four-inch diameter pumping well. Wells installed in
the saprolite and transition zone will be installed using either rotosonic or hollow-stem augers or other
industry-standard method. Depending on drilling difficulty, the boring for the transition zone well may be
completed with an alternative method (e.g., tricone roller bit). Pumping wells completed in the saprolite and
transition zones will be fully screened across each respective unit. The borings for the bedrock pumping
well and associated observation wells will be completed using a combination of air-rotary methods to
advance 8-inch diameter casing into bedrock, followed by coring to a maximum depth of 50 feet into
bedrock with an HQ core barrel to identify fracture intervals, then enlarging the boring with an air hammer
to accommodate the well. As described earlier in Section 3.3.1.2, coring will be performed using the wire-
line method and a triple-tube core barrel, pending availability. Cores will be examined for natural fractures
and will be evaluated for ROD. Where weathered fractures are encountered, a water withdrawal test will be
performed by lowering a submersible pump into the corehole and pumping from the fractured zone until the
water level stabilizes above the pump to evaluate fracture yields. These data will be used to identify the
screen interval for the pumping well and individual observation wells. The bedrock pumping well will be
screened as appropriate to induce water level changes in the fractures located within the upper 20 to 30
feet of bedrock.
Well screens for the pumping wells will be continuously-slotted in order to maximize the open area of the
screen to the formation, particularly given the apparent low to moderate permeability of the saprolite. It
should be noted that to collect the data necessary to assess anisotropy, observation well pairs will need to
be completed in the same water-bearing units as the pumping wells at varying depths and aligned in
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
different directions from the pumping well. Observation wells will be drilled using the same method as the
pumping well for the respective hydrogeologic unit and will be constructed using 2-inch diameter flush-
threaded PVC riser and an appropriate length of No. 10 or 20 slot (0.010 to 0.020 inch slot) well screen.
Sand filter packs and seals for the pumping and observation wells will be constructed as described under
Section 3.3.1.2, taking care to isolate the screen within the hydrogeologic unit being tested. Boring and
well completion logs will be compiled for each well location and will include the following information: a
description of soil lithology using the USCS with descriptors of density, moisture content, color, and grain-
size and depths at which changes in stratigraphy occur; a description of rock cores (where applicable)
including rock type (e.g., gneiss), ROD, recovery, fracture depth, and indications of weathering on fracture
surfaces, well screen length and interval; diameter of well; screen slot size; sandpack and seal intervals;
and the type of surface completion. Following installation, both observation wells and pumping wells will be
developed by surging and purging a minimum of 5 well bore volumes and until the development water is
visibly free of settleable sediment. The placement of bedrock pumping/observation wells will be based in
part on the results of the proposed geophysical survey.
Pumping tests are proposed at locations designated as "X" and "Y" shown on Figure 9. Wells to be
installed for the pumping tests performed at these locations are summarized below.
• Location X-Saprolite and Transition Zone Pumping Tests: Location Xis adjacent to N-1 well
location W-72. This location was selected due in part to the presence of saprolite well MP-17 and
transition zone monitoring well IW-5t, which will be used as observation wells during the pumping
test for these units and its proximity to the plume making further spreading of the plume into less
impacted areas during pumping unlikely. In addition, this location is in an area where boundary
effects (i.e., recharge from surface water) are less likely to affect drawdown data. It is anticipated
that the saprolite pumping well will be installed 5 to 10 feet south of well MP-17. In addition to the
pumping well, four observation well couplets will be installed in the saprolite at this location for the
pumping test. One well couplet will be installed along a north-trending alignment from the
pumping well approximately 15 to 20 feet from MP-17, one well couplet will be installed
approximately 10 to 15 feet northwest of the pumping well, and two well couplets will be installed
along a west to east alignment approximately 5 to 10 feet and 20 to 25 feet from the pumping well,
respectively. Observation wells will be installed using either rotosonic or hollow-stem augers.
During pumping well drilling, splitspoon samples or soil cores will be collected continuously to
competent bedrock and from the deepest boring at each observation well couplet at 5 foot
intervals to the bedrock surface for lithologic classification. These data will be used to select
screen intervals for the observation wells both in saprolite as well as for observation wells for the
transition zone pumping test.
It is anticipated that the pumping well for the transition zone will be installed approximately 5 to 10
feet south of IW-5\. In addition to the pumping well, four observation wells will be installed at the
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
transition zone. One well will be installed along a north-trending alignment from the pumping well
approximately 10 to 20 feet from IW-5t, one well will be installed approximately 10 to 15 feet
northwest of the pumping well, and two wells will be installed along an east to west alignment
approximately 5 to 10 feet and 20 to 25 feet from the pumping well, respectively. Boreholes for the
observation wells will be drilled using rotosonic or hollow-stem augers and completed, if necessary,
with a roller bit or air hammer. Since the transition zone observation wells will be located in close
proximity to the observation wells installed in the saprolite as described above, splitspoon samples
will not be collected at these locations.
• Location Y -Bedrock Pumping Test: Location Y is adjacent to existing openhole bedrock well,
IW-3. This location was selected since IW-3 took water during packer testing performed at the
time of installation whereas two other wells (i.e., IW-1 and IW-2) did not. In addition, IW-3 is
located near a north-south trending alignment of bedrock wells that exhibited a response during a
hydraulic test performed on a hybrid well (i.e., EW-1) during the RI. On this basis, IW-3 is likely
located in an area of interconnected fractures and has a greater potential to exhibit a water level
change in response to pumping and provide information to evaluate the fate and transport of
CVOCs in bedrock groundwater. Therefore, a pumping well will be installed in the bedrock
approximately 10 to 15 feet south of well lW-3. The boring for this well will be extended to a depth
of 120 feet bgs using methods described earlier in this section.
Bedrock well IW-3 will be used as an observation well for the bedrock pumping test. Geophysical
logging indicates the presence of open water-bearing fractures in IW-3 at depths ranging between
approximately 77 feet and 104 feet bgs. This well is currently a four-inch diameter open hole
bedrock well completed to a depth of approximately 128.6 feet bgs. In order to allow this well to be
used for a pumping test, the open borehole will be converted to a 2-inch diameter PVC bedrock
monitoring well. Prior to this conversion, passive-diffusive bag samplers (PDBS) will be installed in
the well to identify fracture zones containing the highest concentration of CVOCs. Based upon the
previous geophysical logging, PDBS will be installed at the following intervals: 77 to 80 feet bgs, 86
to 89 feet bgs, and 103 to 106 feet bgs. After an appropriate equilibration time, the PDBS will be
retrieved and samples will be submitted for analysis of CVOCs (i.e., PCE, TCE, cis-DCE, and vinyl
chloride) using SW-846 Method 8260B. The samples will be handled and preserved in accordance
with chain-of-custody protocols and requirements of the analytical method as specified In the
QAPP. The data from the PDBS will be used to select the screen interval for the PVC monitoring
well.
In order to quantify hydraulic characteristics of the fractured bedrock including anisotropy, three
additional observation wells will be installed for the bedrock pumping test. One of the observation
wells will be installed 20 to 30 feet north of IW-3 and the two 'remaining observation wells will be
completed due east or west of the pumping well at distances of approximately 15 feet and 30 to 40
feet, respectively. The final locations of the borings will be based upon a consideration of
geophysical anomalies identified from the surface geophysical survey, if any, described in Section
3.2.2. The borings for the observation wells will be completed to a depth of 120 feet bgs and
evaluated for water-bearing fractures. Screen intervals will be selected based upon the location of
water-bearing fractures identified from logging of the cores and results of withdrawal tests
performed at discrete fracture intervals.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
3.3.4.3 Pumping Test Methodology-Pre-Test Activities
Several activities will need to be completed prior to performing the pumping tests. These activities include:
• Arranging for treatment and disposal of discharge water generated during pumping, including
obtaining any necessary discharge permits for on-site discharges;
• Installing an on-site rain gage and identifying a nearby weather station for barometric pressure
data (if vented transducers are not utilized for water level measurements); and
• Performing ambient water level monitoring.
Discharge Planning
A key pre-pumping activity will be to arrange for the handling and disposal of pumping test discharge water.
A temporary water treatment system will be used to treat the discharge water prior to disposal. The system
will be comprised of conveyance piping, a minimum of two drums containing liquid-phase granular activated
carbon (GAG), discharge piping, and a flow meter/totalizer. Prior to performing the pumping test, URS will
arrange for a temporary discharge permit with the City of Statesville to allow treated groundwater to be
discharged to an accessible on-site sanitary sewer manhole for disposal at the local publicly owned
treatment works (POTW). The treatment system will include a sufficient amount of GAG to minimize the
potential for breakthrough based upon approximate influent concentration of VOCs and the discharge rate
during the pumping test. Samples of treatment system effluent will be collected for parameters dictated by
the POTW and at a frequency required by the POTW.
Precipitation Monitoring
One of the primary assumptions of analytical models used to analyze pumping test data is that there are no
sources of external recharge during the pumping test (e.g., no significant precipitation). Since the
occurrence of local precipitation events is not always predictable, a temporary rain gage will be set up on
site in the area where the pumping tests will occur to help quantify precipitation, if it occurs, and its impact
on the data, if discernable. The rain gage will consist of an open cylindrical container, which will be located
in an open area on the site away from buildings and trees near N-1 well location W-45. This location is
more than 100 feet from the nearest building and large trees. At a minimum, precipitation will be monitored
on a daily basis (72-hour period) during performance of the pumping test and at the end of each rainfall
event. The quantity of precipitation, the time of the observation, and the approximate start and end time of
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
precipitation events that occur during the pumping test will be recorded in a project field book. It should be
noted that for the ambient water level monitoring period prior to the pumping test discussed below,
precipitation measurements will be obtained from one of the three National Weather Service weather
stations located in Statesville in the event that URS personnel are not present on site for the duration of the
monitoring period. Barometric pressure data will also be obtained from one of the National Weather
Service weather stations to assess potential impacts on water levels at the observation wells where water
levels are monitored using non-vented transducers.
Ambient Water Level Monitoring
Drawdown observed during a pumping test can be affected by factors for which no allowances are made in
the analytical solutions used to evaluate the data, These factors can include unidirectional changes (i.e.,
natural recharge or drainage of the aquifer) or rhythmic changes (i.e., leakage from sewers and/or drains,
or changes in barometric pressure). Water level changes due to barometric changes can also be non-
rhythmic, In order to assess whether such factors have a potential to affect drawdown measurements,
ambient water levels will be monitored in the observation wells located in the vicinity of the pumping well for
a minimum of three days preceding the constant-rate pumping test in each· hydrogeologic unit, If
unidirectional changes or rhythmic fluctuations are identified, these data will be used to the extent feasible,
to adjust the drawdown data collected during the pumping test prior to analysis, using the following
equations, as applicable:
• For unidirectional changes in groundwater levels indicative of natural recharge, corrected drawdown
will be calculated as s' = s + tih, where s' is the drawdown adjusted for natural recharge, s is the
measured drawdown during the test at a time since pumping started, t, and tih is the projected
increase in water level due to natural recharge between t = 0 and t.
• For unidirectional changes in groundwater levels indicative of natural drainage, corrected drawdown
will be calculated as s' = s -tih, where the terms are identical to those above except due to natural
drainage, not recharge.
• If water level changes at a particular well are found to correlate with fluctuations in barometric pressure,
then a barometric efficiency factor will be calculated for that particular well and used to correct the
water level using the following equation:
BE= (W/B) '100
where:
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BE = Barometric efficiency;
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
W = The change in water level due to change in barometric pressure (feet); and
B = The change in barometric pressure relative to the start of water level monitoring
(converted to feet of water).
s' = s + !::,W for barometric pressure that is lower than at the start of pumping, and
s' = s -!::,W for barometric pressure that is higher than at the start of pumping.
3.3.4.4 Pumping Test Methodology -Stepped-Rate Drawdown Test
Procedures
Prior to initiating ambient water level monitoring and the constant rate pumping test, a stepped-rate
drawdown test will be performed on each pumping well in order to identify an optimum discharge rate that
will adequately stress each groundwater system and effect drawdown at far as practicable from the
pumping well during the constant rate test. An electrical submersible pump will be temporarily installed in
the pumping well approximately one to two feet off from the bottom of the well and the discharge line will be
equipped with a manually operated flow control valve and an in line flow meter. The valve will be installed
downstream from the flow meter to minimize the potential for inaccurate measurements due to turbulent
flow and to maintain sufficient back-pressure to operate the flow meter. The pump will be powered by a
portable generator. In addition, a transducer will be installed above the pump and programmed to collect
drawdown data as described below for the constant rate test. During this test, the pump will be operated at
up to five different discharge rates varying from low to high during the test. The maximum discharge rate
and pump selection will be based upon observations of well yield made during well development. Pumping
will continue at the step-specific discharge rate until drawdown stabilizes at an asymptotic level. It is
anticipated that the duration of each step will be one to two hours. When the drawdown in the pumping
well has stabilized, the discharge will be incrementally increased and water levels will again be monitored
until drawdown stabilizes at the new discharge rate. This process will be repeated until a constant head of
approximately three to five feet of water is maintained above the top of the transducer and pump intake.
The final discharge rate that achieves this criterion will be used as the optimum discharge rate for the
constant rate pumping test.
During the stepped-rate test, discharge will be routed through the temporary treatment system described
earlier and discharged to an on-site sewer for disposal at the Statesville POTW. After performing the
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
stepped-rate drawdown test, the water level in the pumping well will be allowed to equilibrate to static
conditions overnight or until the water level recovery is within 10 percent of the original static water level or
water level recovery ceases, whichever occurs first. Upon recovery, ambient water level monitoring
described in Section 3.3.4.3 will be initiated, followed by the constant rate pumping test described in the
following section.
3.3.4.5 Pumping Test Methodology -Constant Rate Test Procedures
Excluding the stepped-rate drawdown test, URS anticipates that the pumping test, including ambient water
levels and the recovery test will be performed over the course of 7 to 8 days for each hydrogeologic unit,
assuming no significant rainfall. During the constant-rate pumping test, drawdown will be monitored over a
minimum period of 72 hours followed by a minimum 48 hour recovery period. Once the tests start, round-
the-clock oversight will be needed to: monitor the discharge rate; collect periodic water levels from
observation wells for quality assurance checks; keep the generator filled with gas; and for security
purposes. Prior to beginning a 72-hour pumping test for each hydrogeologic unit, static baseline water
levels will be collected from the pumping well, nearby observation wells and any other monitoring wells in
the area that are deemed to provide useful information. Observation wells proposed for water level
monitoring during each constant rate pumping test (including ambient monitoring) are tabulated below:
TABLE 6
PROPOSED OBSERVATION WELLS FOR WATER LEVEL MONITORING
DURING PUMPING TESTS
.. Saprolite Pumpinq Test
Saprolite Pumpinq Well (New)
W-7s
MP-17
W-19s
W-72
W-35s
New saprolite well couplet 1
New saprolite well couplet 2
New saprolite well couplet 3
New saprolite well couplet 4
W-1 Os (background H2O level)
IW-St
New transition zone well 1
URS Corporation
FCX STATESVILLE SUPERFUND SITE
STATESVILLE, NORTH CAROLINA
:rransition Zone Pumpiiiq Test
Transition Zone Pumping Well (New)
IW-4t
IW-St
IW-6t
W-34t
W-35t
New transition zone well 1
New transition zone well 2
New transition zone well 3
New transition zone well 4
MP-17
New saprolite well couplet 1 (closest
to pumping well north)
New saprolite well couplet 3 (closest
3-37
'Bedrock Pumpina Test
Bedrock Pumpinq Well (New)
IW-3
New bedrock well 1
New bedrock well 2
New bedrock well 3
IW-2
W-9i
W-16i
W-33i
IW-4t
W-Bi
W-26i
April 28, 2009
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Saprolite Pumping Test
(closest to pumping well north)
New transition zone well
(closest to pumping well west)
Transition Zone Pumping Test
to pumpinq well west)
3
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
Bedrock Pumping Test
It should be noted that during the pumping tests, water levels will be collected from the following wells using
an electronic water level indicator: W-?s, W-19s, and W-35s during the saprolite pumping test; and IW-4t,
IW-6t, W-34t, and W-35t during the transition zone pumping test. Water levels will be collected from these
wells at a frequency of every two to six hours during the constant rate pumping test. Water levels in the
remaining saprolite and transition zone observation wells and pumping wells will be monitored primarily
using transducers. Since water levels in monitoring wells completed in fractured rock respond relatively
quickly sometimes at significant distances due to low storativity of fractured rock and changes in pressure
head propagated along fractures in response to pumping, water levels in the bedrock observation wells will
be monitored primarily using transducers.
Data collected using the transducers will be performed at a linear scale of every 10 minutes during ambient
water level monitoring and at a logarithmic time scale during the pumping test. During each constant rate
pumping test, water levels will be collected from the observation wells equipped with transducers and from
the active pumping well every two to six hours using a hand held electronic water level meter as a quality
assurance check against water levels collected using the transducers. Discharge measurements will be
checked and verified with a bucket and stopwatch every hour for the first 8 hours of the test and
approximately every two to four hours thereafter until pumping ceases. Water level observations,
discharge measurements, the time, and location of the water level observations will be recorded in a field
notebook and/or pumping test data collection forms.
Transducers will be placed in designated observation wells for collecting "real time" data during the test.
The transducers will be programmed with the static water level measured in the well, transducer
specifications, and other test parameters. After programming the transducers, each transducer will be
raised by a measured increment of at least 0.5 feet and the change in water level monitored by the
transducer will be compared to this measurement. A difference of 10 percent or less will be considered
acceptable. If the difference between the recorded water level change versus the actual change in
transducer depth exceeds 10 percent, the transducer will be reprogrammed and this quality assurance step
will be repeated. If a difference of greater than 10 percent is again observed, the transducer will be taken
out of service and replaced. If, however, the difference between the change in water level measured by the
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
transducer and the change in the depth of the transducer agree within 10 percent, the transducer will be
considered acceptable for water level monitoring.
The constant-rate test will be initiated by preprogramming each transducer to begin collected data at a
designated time. At the designated time, the pump will be activated and the discharge rate will be adjusted
to match the rate identified from the 8-hr stepped-rate drawdown test. At the beginning of the test, the
control valve will be set to a flow rate below optimum fi'ow rate, determined from the stepped-rate test, so
as to provide sufficient back pressure for operation of the flow meter. The flow control valve then will be
adjusted to the position corresponding to the selected flow rate determined from the stepped-rate
drawdown test. During the test, URS field personnel will monitor (1) operational issues (maintaining steady
pumping rate, water disposal, maintaining proper fuel level in generator, and electrical/power), and (2)
general observations about site conditions (e.g., rainfall or other events that could potentially affect the
data).
After cessation of pumping, recovery will be monitored for a maximum of 48 hours or until recovery rates
reach asymptotic levels, whichever occurs first. URS personnel will collect water level data manually
during the recovery phase at the same frequency as during the active pumping portion of the test for quality
assurance.
3.3.4.6 Pumping Test Methodology -Pumping Test Data Analysis
Upon completion of each data collection event (i.e., stepped-rate drawdown test, ambient water level
monitoring, constant-rate drawdown test, and post pumping recovery), data will be downloaded from the
transducer/data logger, corrected as needed to account for unidirectional, rhythmic, and/or non-rhythmic
effects. The data will then evaluated using an appropriate analytical solution (e.g., Theis, Neuman,
Hantush, Walton, DeGlee, etc.) for the aquifer condition (i.e., unconfined [saprolite], confined [potentially
fractured bedrock], leaky-confined, or leaky unconfined [potentially the transition zone]) and type of test
(i.e., stepped-rate drawdown test or constant-rate pumping test). Anisotropy will be evaluated using
methods developed by Hantush (1966) as presented in Kruseman and DeRidder (1983). Data analysis will
be facilitated by the aquifer testing software package referred to as AQTESOLV®. In addition to the
determination of specific aquifer characteristics, distance vs. drawdown graphs and time vs.
drawdown/recovery plots will be generated during data analysis and included as part of a technical
memorandum describing the pumping test data collection activities and data analysis. The graphical data
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
plots will be evaluated for evidence aquifer boundary effects, Such evidence, if identified will be discussed
in the memorandum.
3.3.5 Groundwater/Mass Flux
Groundwater flux and mass flux will be measured through a cross-section of the plume along the alignment
of the N-1 well locations.
3.3.5.1 Approach
Groundwater/mass flux measurements will be used to:
• Provide an understanding of the mass of PCE leaving the source area, which when coupled with
an understanding of PCE mass in the source (which is addressed under a separate work plan), can
be used to provide an estimate of the life expectancy of the source area; and
• Provide a mechanism for assessing the calibration of the numerical groundwater flow and transport
model previously referenced in this document.
Mass flux, which can be defined as contaminant concentration times seepage (or Darcian) velocity at any
given location within an aquifer, is becoming a more commonly used parameter for evaluating the I performance of a remedial treatment in a quantified manner, particularly at DNAPL sites. In addition, mass
flux can be a useful tool for assessing the calibration of numerical groundwater solute transport models.
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This concept represents an extension of the commonly used metric of groundwater contamination
concentration. Whereas groundwater contaminant concentration measurement is valid for a single point in
space and time, mass flux surveys can provide a better quantitative understanding of contaminant
transport, mass removal rates, and effectiveness of remediation systems.
3.3.5.2 Methodology
Mass flux can be estimated from the results of several tracer test methods (API, 2003) including natural
gradient tests, induced gradient tests, and a relatively new method developed by researchers at the
University of Florida at Gainsville using a device referred to as a passive flux meter (PFM), which EPNG
proposes to use to assess mass flux at the Site.
A PFM is a device used for direct in-situ measurement of both cumulative water and contaminant fluxes I (Annable et al., 2005; Hatfield et. al., 2004). The PFM may be used to provide depth-discrete
measurements of groundwater flux and mass flux, average concentrations of organic compounds in
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
groundwater, and vertically discrete estimates of hydraulic conductivity when hydraulic head data 1s
available for such zones.
The PFM device is a self-contained permeable unit that is inserted into a well or boring, which allows
groundwater flow through the device. The interior composition of the PFM is a matrix of a permeable
sorbent that retains dissolved contaminants present in the groundwater intercepted by the unit. After a
specified period of exposure to groundwater flow, the PFM is removed from the well or boring. The sorbent
is carefully extracted to quantify the mass of all contaminants intercepted by the PFM and the residual
masses of all tracers. The contaminant masses are used to calculate time-averaged contaminant fluxes,
while residual resident tracer masses are used to calculate cumulative groundwater flux. Depth variations
of both water and contaminant mass fluxes can be measured in an aquifer from a single PFM by vertically
segmenting the exposed sorbent packing and analyzing for resident tracers and contaminants. Thus, at
any specific depth, an extraction from the locally exposed sorbent yields the mass of resident tracer
remaining and the mass of contaminant intercepted. These data are used to estimate local cumulative
water and contaminant fluxes.
A potential limitation that has been observed with this device is the influence of sandpack in the presence
of significant vertical hydraulic gradients. Wells with a sandpack that is more permeable than the adjacent
native materials can facilitate vertical contaminant flux along the well screen resulting in measurement bias.
It should be noted that recent vertical flux measurements made in selected N 1 wells reportedly did not
exhibit a significant component of vertical in-well flow. Consequently, the above limitation would not appear
to adversely affect the N1 wells, particularly since baffles are used when deploying multiple flux meters in a
well.
After a pre-specified period following installation, the PFM devices would be retrieved from the individual
wells and analyzed for the CVOCs that adsorbed to the PFM matrix and the amount of tracer remaining.
The data will be analyzed to generate plots of groundwater flux, mass flux of individual organic compounds,
estimates of depth discrete hydraulic conductivities (assuming a uniform horizontal hydraulic gradient that
is constant with depth in the specific hydrogeologic unit screened by the well, which is reasonable based
upon vertical flow measurements in selected N-1 wells), and estimates of contaminant concentration.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
The PFM approach to estimate groundwater and mass flux will be implemented using existing wells along
the N 1 transect installed for ANA injections, existing monitoring wells near and along the N-1 transect, a
new transition zone monitoring well adjacent to W-1 0s/i and two supplemental bedrock wells adjacent to
wells W-61 and W-85. The supplemental bedrock wells will be initially completed as openhole bedrock
wells to a depth of 130 feet bgs using an air hammer or rotosonic drilling. Upon completion, the well will be
developed to remove drilling fluids and then logged using the geophysical methods described in Section
3.3.2. PFMs will be installed at approximately two-foot intervals along length of the saturated zone that is
screened by other wells completed in the saprolite and transition zone and at discrete fracture intervals at
bedrock well locations. Each PFM is approximately 1.7 feet long and will be separated from lower PFMs
using baffles to minimize the potential for vertical mixing (which, as noted earlier, is low) from other tested
zones. The wells where PFMs will be implemented are tabulated below and depicted on Figure 9:
Well Location
Saprolite!Transition
' Zone Wells
W-8s
W-10s
W-43
W-48
W-61
W-71
URS Corporation
Table 7
Proposed Passive Flux Meter Locations
FCX Statesville Superfund Site
Statesville, North Carolina
Approximate PFM Well Location· :oepth Interval
(feet) Bedrock Wells
25 to 35 IW-1
28 to 35 IW-2
30 to 70 IW-3
33 to 68 W-10i
32 to 59 New Bedrock Well, W-
61 i, adjacent to W-61
32 to 60 New Bedrock Well, W-
85i Adjacent to W-85
3-42
Approximate PFM
Depth Interval
'
(feet)
I
124.5 to 126.1
79.3 to 81
104.5 to 106.2
12410125.7
128 to 129
77 to 78.7
79 to 80.7
86.5 to 88.1
103.5 to 105.1
118.510120.1
121.5 to 123.1
126.5 to 128.1
59 to 69
To be determined from
borehole geophysical
logging
To be determined from
borehole geophysical
logging
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Well Location Approximate PFM
Depth Interval
Saprolite!Transition (feet) Zone Wells
W-85 32 to 49
New Transition Zone 42 to 52
Well W-10t
Groundwater Plume Assessment Work Plan
FCX {Statesville) Supertund Site {OU3)
Statesville, North Carolina
Well Location Approximate PFM
Depth Interval
Bedrock Wells (feet)
Upon completing mass flux measurements using the PFMs, openhole bedrock wells will be comP.leted as
two-inch diameter PVC monitoring wells screened across discrete fracture intervals. The screen intervals
will be selected based upon the mass flux measurements and will, in all likelihood, correspond to fracture
zones exhibiting the highest mass flux, since concentration trends in these zones may be a good indicator
of mass reduction in the source area and the effectiveness of the source area remedy. These wells will be
constructed and developed in the same manner as the plume delineation monitoring wells described earlier
in Section 3.3. 1.2.
3-4 Plume Evaluation/Monitoring
Upon completion of the investigative tasks described herein, a well location/elevation survey will be
conducted, groundwater samples will be collected and analyzed from the newly-installed monitoring wells,
and a statistical trend analysis will be conducted to evaluate plume stability.
3.4.1 Well/Boring Location Survey
Each of the newly installed monitoring wells will be surveyed to establish the horizontal and vertical (elevation)
positions of the wells relative to the existing monitoring well network. Horizontal and vertical accuracy will be
within 1 and O.Q1 feet, respectively. Surveying will be conducted by a surveyor licensed in the State of North
Carolina. The surveyor will provide an updated base map showing the locations of the new wells along with
elevations for ground surface, the top of the PVC riser of the monitoring wells, and the rim elevation for the
steel protective casings.
3.4.2 Groundwater Sampling and Analysis
Following installation, groundwater samples will be collected from each monitoring well cluster identified in
Section 3.3.1.1 to verify that the extent of the CVOC plume originating from the Site has been adequately
delineated. Following this initial confirmatory sampling event, a second, comprehensive set of groundwater
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
sampling will be performed concurrently with semi-annual sampling performed as part of the long-term
monitoring program for the Site.
3.4.2.l Approach
The purpose of the comprehensive monitoring event will be to provide a data set that fully delineates the
CVOC plume for the predictive groundwater flow and transport model referenced earlier. Samples
collected from the wells will be analyzed for PCE, TCE, cis-DCE, and vinyl chloride using SW-846 Method
82606. Wells that will be sampled as part of the comprehensive monitoring event are shown on Figure 10
and summarized in Table 8.
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TABLE 8
Groundwater Plume Assessment Work Plan FCX (Statesville) Supertund Site (OU3) Statesville, North Carolina MONITORING WELLS TO BE SAMPLED AS PART OF COMPREHENSIVE GROUNDWATER MONITORING EVENT FCX STATESVILLE SUPERFUND SITE STATESVILLE, NORTH CAROLINA Saprolite Monitoring Wells Transition Zone Monitoring-We/ls Bedrock Monitoring Wells W-1s EW-3 IW-4t W-1i W-2s EW-4 IW-St W-2i W-3s EW-5 IW-6t W-Si W-4s EW-6 W-10t W-9i W-Ss EW-7 W-21t W-10i W-6s EW-8 W-30t W-12i W-7s EW-9 W-34t W-13i W-8s EW-10 W-35t W-14i W-9s EW-11 W-36t W-16i W-10s EW-12 W-38t W-20i W-11s EW-13 W-40t W-22i W-13s EW-14 W-411 W-26i W-16s EW-15 New T ransilion Zone, Well Cluster A W-28i W-17s EW-16 New T ransilion Zone Well, Cluster B W-29i W-18s EW-17 New Transition Zone Well, Cluster C W-30i PZ-90 EW-18 New Transition Well, Cluster D W-31i W-19s EW-19 New Transition Zone Well, Cluster E W-32i W-20s EW-20 New Transition Zone Well, Cluster F W-33i W-21s EW-21 New Transition Zone Well, Cluster H (if installed) W-42i W-23s EW-22 New Transition Zone Well, Cluster I (if installed) W-20d W-24s EW-23
W-28d W-25s EW-24
W-33d W-27s MW-1
IW-1* W-31s MW-Gs
IW-2* W-35s MW-2
IW-3* W-36s MP-1
New Bedrock Wells, Cluster A W-38s MP-3
New Bedrock Wells, Cluster B PZ-22s MP-4
New Bedrock Wells, Cluster C PZ-16W MP-7
New Bedrock Wells, Cluster D New Saprolite Wells, Cluster A MP-8
New Bedrock Wells, Cluster E New Saprolite Wells, Cluster B MP-15
New Bedrock Wells, Cluster F New Saprolite Wells, Cluster C MP-16
New Bedrock Well, Cluster G New Saprolite Wells, Cluster D MP-17
New Bedrock Wells, Cluster H (if installed)
New Saprolite Wells, Cluster H (if installed)
New Bedrock Wells, Cluster I (if installed)
New Saprolite Wells, Cluster I (if installed)
New Source Area Bedrock Wells (if installed)** EW-2
Notes: • = Fracture zones in these wells were previously identified from acoustic televiewer logs. Vertically discrete samples will be collected from the fracture intervals using passive diffusive bag samplers for analysis of PCE and its daughter compounds TCE, cis-DCE, and VC.
Field parameters in these wells will be sampled using a downhole sonde. " = Source area bedrock wells described in Source Area Investigation Pian.
URS Corporation
3-45
April 28, 2009
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,1
3.4.2.2 Methodology
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
A variety of methods will be used to obtain groundwater samples depending upon the well construction as
described below.
Low-Flow Sampling
At monitoring wells constructed of conventional PVC materials, groundwater sampling will be performed in
general accordance with the EPA Low Flow Sampling Method as described in the most recent update of
Low-Flow (Minimal Drawdown) Groundwater Sampling Procedures (EPA, 1996). Prior to purging the well,
the water level in the well will be measured using an electronic water level meter with an accuracy of ±0.01
foot and the volume of water contained in the well screen will be calculated using information presented on
the well construction log. The well will subsequently be purged of a minimum of one screen volume (three
if possible) using a dedicated bladder pump, a precleaned variable speed submersible pump or peristaltic
pump (depending upon the depth to groundwater in the well) equipped with well-dedicated polyethylene
tubing. The pump intake will be set near the midpoint of the water column in the screen interval. The
discharge rate will be controlled to minimize drawdown, to the extent feasible, in wells screened across the
water table and avoid dewatering the well screen of wells screened below the water table.
After purging one well screen volume from the well, field indicator parameters (i.e., pH, temperature,
specific conductance, redox potential, and dissolved oxygen) will be measured at three to five minute
intervals using a Yellow Springs Instruments (YSI) Model 650 Water Quality Meter or equivalent equipped
with a flow cell. The meter will be calibrated at the beginning of each day using appropriate calibration
standards and checked for drift at the end of each day. Calibration records will be maintained in a field
' notebook. Measurements of static water level, field indicator parameters, drawdown, and purge rate will be
recorded in a field notebook and/or on summary field sample data sheets. Purging will continue until three
consecutive measurements meet the following criteria:
• pH does not vary by more than :!:0.1 standard pH unit;
• Temperature does not vary by more than 1 degree Celsius (°C);
• Specific conductance does not vary by greater than :!:10 percent;
• Dissolved oxygen when greater than 1 milligram per liter (mg/I) does not vary by more than 10
percent or by greater than :!:0 2 mg/I when less than 1 mg/I; and
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I • Redox potential does not vary by more than:!: 10 millivolts (mv).
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
I Upon reaching stabilization, the flow cell will be disconnected from the pump discharge line and samples
will be collected into pre-preserved sample containers for analysis. A separate aliquot of sample will be
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collected into a separate container for measurement of turbidity. If encountered, wells that purge dry at low
flow rates (i.e., <300 milliliters) will be sampled with a bailer once the well has sufficiently recharged. Purge
water generated during sampling will be collected and managed for off-site disposal by a licensed
contractor.
Passive Diffusion Bag Samplers
As indicated above in the tabulation of monitoring wells to be included in the comprehensive monitoring
event, three bedrock monitoring wells (i.e., bedrock wells IW-1 through IW-3), will be sampled using PDBS.
PDBs are permeable polyethylene bags that contain volatile-free water. When placed in a monitoring well,
VOCs, if present in groundwater, diffuse across the polyethylene into the water contained in the PDBS in
response to the concentration gradient that exists between groundwater and the water inside the PDBS.
Eventually, the concentrations of organic compounds inside the PDBS reach a state of quasi-equilibrium
with groundwater providing a representative concentration of the organic compounds in the groundwater.
The use of PDBS in characterizing groundwater quality has been extensively documented (Vroblesky et.
al., 2001 a, 2001 b; ITRC, 2004; and USAF, 2005) and is an accepted method by EPA for measuring
concentrations of CVOCs in groundwater. PDBS will be installed in the three wells at the depth intervals
presented in the following table, corresponding to potential water-bearing fractures identified from acoustic
televiewer logs generated by a previous consultant.
. Depth of-Fracture 'Identified ,PDB Sample Interval Monitoring Well with Acoustic Televiewer (feet ,. ' '
(bgs) (feet bgs)
IW-1 125.5 124 to 126
IW-2 79.9 79 to 81 80.8
105.1 104 to 106
125 12410126
128.8 . 127 to 129
IW-3 77.6
77.7 77 to 80
79.9
87.4 86 to 88
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Depth of Fracture Identified
Monitoring Well with Acoustic Televiewer (feet
(bgs)
104.7
119.3
122.3
127.1
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
PDB Sample Interval
(feet bgs)
103.5 to 105.5
118 to 120
121 to 123
126 to 128
The PDBS will be installed, at a minimum, approximately two to three weeks prior to the remainder of the
sampling activities to allow the PDBS to reach equilibrium with the surrounding groundwater. The PDBS
will be hung inside the wells using 30 to 40 pound test monofilament line. At the end of the equilibration
period, the PDBS will be retrieved and their contents transferred into appropriately preserved laboratory
supplied sample containers. After retrieval, field indicator parameters will be monitored in-~itu using the
YSI MOS 650 water quality meter equipped with a downhole sonde. In addition to providing information on
the vertical concentration distribution of CVOCs in bedrock, the PDBS data may be used to provide
recommendations regarding the design of a longer-term liner/sampling system (e.g., Flute®) for wells IW-2
and IW-3, which have multiple fracture zones.
Multi-level Well Systems
As noted in Section 3.3, 1.1, new bedrock wells proposed at Locations A and D, and potentially at
Locations H and I, will be constructed using the Westbay® Multilevel Well System or an equivalent system.
The Westbay® System and similar multilevel sampling systems allows for the collection of discrete samples
from multiple zones within the same borehole. The Westbay® System consists of a series of sampling
ports integrated along a single well casing, which is typically filled with distilled water. The sampling ports
are maintained in a closed position that prevents groundwater from entering the well, except when
sampling, collecting pore pressure measurements, and conducting hydraulic tests. At the time of sampling,
a sampling probe equipped with a sample collection vessel is lowered into the well to the desired sampling
port. Upon reaching the sampling port, the probe is pneumatically activated to open the sampling port,
which allows for the collection of a discrete groundwater sample from that interval. Samples are collected
from other sampling ports at various depths in the same manner. After sampling, a separate tool is lowered
into the well to obtain measurements of pressure at each sampling port, which will be used to calculate to a
water level elevation. Indicator parameters affected by exposure to the atmosphere (i.e., dissolved oxygen
and redox potential) will not be measured at the multilevel well system locations since the sampling method
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
at these locations does not allow for use of a flow cell. An aliquot of sample will be collected from each
sample port for measurement of other indicator parameters (i.e., pH, specific conductance, temperature,
and turbidity) at the ground surface using the YSI model MOS 650 water quality meter or equivalent.
General Sample Collection Procedures
Groundwater sample containers will be labeled with the following information: sample location/identification,
date and time of sample collection, requested analytical parameter and analytical method, sample
preservative, and the sampler's initials. Following collection, samples will be logged on a chain-of-custody
form and placed in a secure cooler with ice for shipment by courier service to the laboratory for analysis.
Prior to and between uses at each monitoring location, reusable equipment (i.e., submersible pumps, flow
cells, and Westbay® sample probe) will be cleaned using a solution of distilled water and Alconox® or
Liquinox® followed by a rinse with distilled water. Spent cleaning solutions along with purge water
generated during sampling will be collected and disposed of off-site by a licensed disposal contractor.
Field and laboratory QA/QC samples will be collected during each sampling event as described in the
updated QAPP to provide data to evaluate the representativeness, accuracy and precision of analysis, and
the effectiveness of decontamination procedures.
Analytical results for the QA/QC samples will be reviewed and evaluated along with calibration records,
tuning results, surrogate spike recoveries, holding times, and detection limits to verify the usability of the
data with or without qualifications. The data review will follow the most recent EPA national data validation
functional guidelines for evaluating laboratory analytical data for volatile organic compounds. Results of the
data will be documented in data validation memoranda along with qualifications to the data (if any) resulting
from the review information presented in the laboratory analytical data packages.
3.4.3 Plume Stability Analysis
In order to demonstrate that potential risks associated with impacted groundwater are adequately
controlled, a statistical trend analysis will be performed on data from selected wells within and near the
margins of the plume, if the data sets are sufficient (i.e., minimum of four rounds of data from the same
water level condition -high, low or average water levels).
3.4.3.1 Approach
The wells proposed for statistical analysis are shown on Figure 10 and summarized in Table 9.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
TABLE 9
WELLS PROPOSED FOR STATISTICAL TREND ANALYSIS
FCX STATESVILLE SUPERFUND SITE
STATESVILLE, NORTH CAROLINA
Saprolite!Transition Zone Wells Bedrock Wells
MW-1 W-2i
MW-2 W-Bi
W-2s W-9i
W-4s W-10i
W-5s MW-11
W-6s W-12i
W-Bs W-13i
W-10s W-15i
W-13s W-20i
W-15s W-20d
W-18s W-26i
W-20s W-29i
W-21s W-31i
W-23s W-32i
W-24s
W-31s
MW-10 (transition zone well) '
Note: There are no transition zone wells al the margins of the plume.
The statistical trend analysis will evaluate the concentrations of PCE at individual monitoring wells, in order
to identify wells that exhibit statistically significant trends or demonstrate that contaminant plumes are
stable. Trend evaluation results from individual monitoring wells will then be interpreted within the
hydrogeologic context of the site to describe site-wide trends in plume behavior.
3.4.3.2 Methodology
The Mann-Kendall Trend Test and the coefficient of variation (CV) test will be used to identify decreasing,
stable or increasing concentration trends at individual wells and, by extension, identify decreasing, stable or
increasing plumes. The plume stability evaluation using the Mann-Kendall analysis will use the following
approach and assumptions:
• A confidence level of 85% was deemed appropriate for trend evaluations.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
• Mann-Kendall trend evaluations will be performed on datasets that are filtered to remove
seasonality.
• Trend results for individual wells will be interpreted taking into consideration the location of
source area(s), groundwater flow directions and approximate dissolved plume locations.
Analytical data from site perimeter monitoring wells often have many consecutive rounds of non-detect data
interspersed with several rounds that include detected compounds. Since the non-detect values are all
considered equal in the Mann-Kendall evaluation, the result is often a determination of "no trend."
However, the validity of the "no trend" result is drawn into question because the Mann-Kendall test does not
take into account the variability in the dataset. Since the identification of no trend is important for the
evaluation of stable plumes, the CV is used to measure the variability within each dataset.
CV = Standard Deviation / Arithmetic Mean
The CV should be less than or equal to 1 for a Mann-Kendall "no upward or downward trend" result to be
considered a stable trend. If the CV is greater than 1, the trend is considered unstable. Thus, in order to
show a stable or attenuating plume, one would look for a preponderance of wells, especially at the edges of
a plume, that show a decreasing trend or no trend in the Mann-Kendall analysis with a coefficient of
variation less than or equal to one.
I 3.5 Updated CSM/Data Gap Investigation Report
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Results of the field investigation activities described in this work plan will be incorporated into an Updated
Conceptual Site Model/Data Gap Investigation Report, which will document investigations completed to
address data gaps identified in the Conceptual Site Model and Data Gap Analysis Report (URS, 2008).
The report will also document the findings of addition investigations described in other work plans, which
will have been submitted to EPA and NCDENR including:
• Receptor Survey Work Plan;
• Sewer Line Investigation Work Plan;
• Surface Water Assessment Work Plan; and
• Soil Gas Assessment Work Plan.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Sile (OU3)
Statesville, North Carolina
The updated CSM will provide the basis for the predictive groundwater fate and transport model previously
discussed in this work plan, and will be described in detail in a separate work plan, to be submitted to EPA
and NCDENR.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
4.0 ANALYTICAL PROGRAM AND FIELD OPERATIONS
EPNG intends to update the existing QAPP to include information relevant to investigatory activities
planned for the remainder of 2009 through 2010. A copy of that QAPP will be submitted to EPA and
NCDENR separately. A QAPP is currently in place for the FCX Statesville OU3 Site (Brown and Caldwell,
February 2004). The site-specific QAPP provides detailed information concerning the organization,
activities, and QA/QC protocols needed to achieve project data quality objectives (DQOs). The information
provided in this section is not intended to duplicate the content, information, or procedures presented in the
QAPP. Information provided in this section is intended to supplement the QAPP with specific information or
procedures directly related to the groundwater plume delineation investigations described herein. For topics
not specifically included in this section, the reader is directed to the QAPP.
4.1 Analytical Program
4.1.1 Data Quality Objectives
DQOs are qualitative and quantitative statements that specify the quality of the data required to support •
decisions made during field activities and are based on the end uses of the data. DQO levels address
various data uses, and the QA/QC effort and methods that are required to achieve the desired level of data
quality. These DQO levels include:
• Field Screening (DQO Level I): This DQO level is characterized by the use of portable
instruments such as field water quality instrumentation, colorimetric tubes and/or an FID or PIO
which can provide real-time data to assist in the optimization of sampling locations and health and
safety support. Data can be generated regarding the presence or absence of certain contaminants
at sampling locations. Level I DQOs have been established for activities presented in this work
plan. These DQOs include the following: 1) Use of an FID and Color Tee® colorimetric tubes to
provide semi-quantitative data to define changes in the magnitude of CVOC impacts with depth in
saprolite, transition zone, and within discrete fractures, to assist in selecting groundwater
monitoring intervals for permanent wells; and 2) Use of the YSI Model MOS 650 water quality
meter and turbidity meter to measure field parameters during groundwater sampling.
• Field Analyses (DQO Level II): This level is characterized by the use of portable analytical
instruments, which can be used on site, or in a mobile laboratory stationed near a site. Depending
upon the types of contaminants, sample matrix, and personnel skills, qualitative and quantitative
data can be obtained. There are no Level II DQOs established for the groundwater plume
delineation field activities.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, Nol1h Carolina
• Screening Data with Definitive Confirmation (DQO Level 111): These data are generated by
rapid, less precise methods of analysis with less rigorous sample preparation. Sample preparation
steps may be restricted to simple procedures such as dilution with a solvent, instead of elaborate
extraction/digestion. Screening data provides analyte identification and quantification, although the
quantification may be relatively imprecise. At least 10% of the screening data should be confirmed
using appropriate analytical methods and QA/QC procedures and criteria associated with definitive
data. Screening data without associated confirmation data are not considered data of known
quality. Use of the MIP to identify potential zones of impacted groundwater to identify well locations
is considered DQO Level Ill, since monitoring wells and subsequent groundwater sampling will be
performed to confirm the level of impacts identified by the MIP.
• Definitive Data (DQO Level IV): These data are generated using rigorous analytical methods,
such as approved EPA reference methods. Data are analyte-specific, with confirmation of analyte
identity and concentration. These methods produce tangible raw data (e.g., chromatograms,
spectra, or digital values) in the form of paper printouts or computer-generated electronic files.
Analysis may be conducted at the site or at an off-site location, as long as the QA/QC requirements
are satisfied. To be definitive, either the analytical or total measurement error must be determined.
Laboratory generated chemical analysis of groundwater samples collected as part of the plume
assessment investigations, to confirm the extent of the plume as described herein, are considered
to be definitive analytical data (i.e., Level IV DQO) as are the data generated from PFMs.
4.1.2 Analytical Methods
Aqueous (groundwater) samples collected during the proposed investigation will be analyzed for PCE and
its daughter compounds by Accutest Laboratories (Accutest), a North Carolina-certified laboratory.
Accutest has a quality control program in place that is comparable to the EPA Contract Laboratory Program I to ensure the reliability and validity of the analyses performed. Analytical procedures are documented as
standard operating procedures, which specify the minimum requirements for each procedure. The
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Laboratory-specific QAPP is available for review upon request. Data generated by the laboratory will be
considered as Definitive Data (DQO Level IV).
4.1.3 Quality Control Samples
Field and laboratory QA/QC samples will be collected to evaluate the representativeness and usability of
groundwater analytical data generated as part of the groundwater plume assessment investigations
described herein. A discussion of specific quality control samples, the method of collection, and the
frequency of analysis will be discussed in an updated QAPP along with parameters that will be evaluated to
assess representativeness and usability. The updated QAPP will be submitted to EPA and NCDENR
under a separate cover.
URS Corporation 4-2 April 28, 2009'
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Sile (OU3)
Statesville, North Carolina
4.2 Field Operations
Field operations will be conducted in accordance with the specifications and procedures provided in an
updated QAPP that is revised to include certain modifications/enhancements to address specific
investigation activities, not covered in the current QAPP. The updated QAPP will include Standard
Operating Procedures (SOPs) for investigation activities discussed in this work plan along with discussions
of quality control checks that will be implemented to assure that the data collected during the investigations
are accurate, representative, reliable, and usable for the intended purpose. The updated QAPP will also
detail performance evaluation criteria for assessing laboratory analytical data. Calibration procedures for
field instrumentation provided by equipment manufacturers will be incorporated as appendices to the
updated QAPP. A copy of the updated QAPP will be provided to EPA and NCDENR for review and
approval prior to implementing this work plan.
4.2.1 Project Team
URS Corporation has been selected and authorized by EPNG to implement groundwater plume
assessment activities at the Site. Key project team personnel include:
• EPNG Project Coordinator-Brian Johnson (Houston, TX -713.420.3425)
• URS Program Manager-Larry Fitzgerald, PG (Hallowell, ME-207.623.9188)
• URS Deputy Program Manager -Conan Fitzgerald, PE (Morrisville, NC -919.461.1100)
• URS Field Operations Manager/Site Health and Safety Officer -Amanda Taylor, PG (Charlotte,
NC -704.522.0330)
• URS Senior Hydrologist-Jeff Hansen, PH (Hallowell, ME -207.623.9188)
• URS Lead Senior Geologist-Jerry Wylie, PG (Greenville, SC-864.609.9111)
4.2.2 Recordkeeping
Documentation of an investigative team's field activities serves as a basis for technical Site evaluation and
report preparation. It is essential that field documentation provide a clear, unbiased picture of field
activities. Aspects of sample collection, sample handling, and observations will be documented in field
books or on applicable field forms. Bound field books will be used on work assignments requiring field
activities. Entries into field books will be legibly written in indelible ink and provide a clear record of all field
activities.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
The following information will be provided on the inside front cover or the first page of the field book:
• Project Name and Project Manager,
• Site Location,
• Job Number,
• Date,
• Individual to whom the field notebook is assigned.
Instructions and procedures relating to the format and technique by which notebook entries are made are
as follows:
1.
2.
3.
4.
5.
Leave the first two pages blank. They will provide space for a table of contents to be added
when the field notes are complete.
Entries will be made in waterproof ink.
Entries will be made in language that is objective, factual, and free of personal feelings or other
terminology, which might appear unclear or inappropriate.
Entries will be printed as neatly as possible.
Entries will be logged in military time format.
6. Errors in the field notes will be indicated by drawing a single line through the text, ensuring the
text is still legible, and initialing and dating the errors.
7. A new page will be started at the beginning of each day's field activities and any remaining
blank portion of a page at day's end will be marked out with a single initialed line.
8. The person taking notes shall sign, number and date each page.
9. Later additions, clarifications, or corrections must be dated and signed.
Instructions and procedures providing guidance on the information to be recorded on field activities are
provided below:
1. A new page will be used at the start of each day's activities. The date, time, on-site personnel,
and observed weather conditions will be noted. Significant changes in weather conditions will
be noted as they occur.
2. Sketches or maps to identify photo and/or sample locations will be included in the field book.
Landmarks and/or direction of north will be included.
3. On-site health and safety meetings or will be documented.
4. As part of the chain-of-custody procedure, sampling information will include sample number,
date, time, sampling personnel, sample type, designation of sample as a grab or composite,
analysis requested with the analytical method (as appropriate) and any preservative used.
Sample locations will be referenced to sample numbers on a Site sketch or map.
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7.
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
Information for in-situ measurements will include a sample ID number or location ID, date,
time, and personnel taking measurements.
If on-site interviews occur, relevant information obtained will be recorded. Names of persons
interviewed, the interest group represented (if applicable), address, and phone number will be
recorded.
Any other relevant information, which would be difficult to acquire at a later date, will be
recorded. I Copies of field notes and original field data sheets will be presented to the field operations manager as
soon as practicable and will be maintained in the project file.
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4.2.3 Sample Designation
Samples collected for specific field analyses or measurement data will be recorded directly in bound
logbooks (field books) and on field forms (as appropriate) using a designated sample identification.
Standard sample labels will be attached to the sample containers and the labels will carry the designated
sample identification and sample analysis procedure.
All samples collected for analysis will be assigned a unique sample identifier. The identifier will link specific
samples to the location and, if applicable, the depth from which the sample was collected, sample media,
and sample type. The sample identifiers will be recorded on the sample label that is attached to the sample
container, in a project field book and/or sample log, on sample chain-of-custody forms, and in the project
database. The sample designation references location and includes qualifiers.
Sample Location. The first portion of the sample designation will be a one-to three-letter alphabetic code
that will identify the type of sample location as identified below. The codes for investigation-derived waste
samples will correspond to a particular container (i.e., drum, tank, etc) instead of a location.
• M -MIP location,
• B -Soil Boring,
• CGW -Groundwater from soil core location,
• MW or EW -Monitoring or extraction well location,
• IDW -investigation-derived waste (IDW) sample (sample of waste generated by the RI activities).
The initial alphabetic code will be followed by a sequential numeric code for each of the above location
types that specifies the location of the sample horizontally and if appropriate vertically. For example, a
groundwater sample collected from EW-1 would be identified as sample EW1. Similarly, a groundwater
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
sample collected from a depth of 50 to 52 feet at a rock core location from a new bedrock well URS-1 BR
would be designated as URS1BR-CGW50-52.
Qualifiers. The final portion of the sample designation is used to identify quality assurance samples.
Samples that are collected for routine analysis only (i.e., not for quality assurance purposes) will not have
qualifiers appended. Additionally, samples with a qualifier included in the sample designation are
considered secondary and will be used only for data quality assessment. For example, the results from the
analysis of a duplicate sample will not be used in the assessment of Site conditions. Only the results from
the primary sample will be used for assessment. The following qualifiers will be appended to the
appropriate sample type:
• DP -duplicate sample,
• RP -replicate sample, and
• MS/MSD -matrix spike/matrix spike duplicate.
Certain samples will require special sample designations. In general, the samples requiring special
designations are quality control-related samples and include trip blanks and equipmenVrinsate blanks. The
procedures for assigning sample designations for these samples are as follows.
Trip blanks and temperature blanks will accompany each shipping container that contains samples for VOC
analysis. The sample designation for trip and temperature blanks wjll be derived using the date the samples
are shipped:
1. Begin the sample designation with "TB" (for trip blanks) or "TEMP" (for temperature blanks) followed by
the numerical month, day, and year (e.g., TB-01152009 for January 15, 2009).
2. Add a media identifier code (e.g., S for soil or sediment, GW for water)
3. Add a sequential number if more than one trip blank by media is being shipped on a single day (e.g., 2
for the second of two water trip blanks shipped on the same day).
Equipment blanks will be collected from any equipment used in sample collection or processing that is re-l used for more than one sample location and is not equipped with a liner. Equipment blanks will be
designated using the same sample designation for the first sample taken after decontamination procedures.
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The qualifier "RB" will be appended to the sample designation to indicate an equipment rinsate blank. For
example, for an equipment blank from a pump after decontamination and before sampling monitoring well
W-1 s , the sample designation for the equipment blank will be W-1 sRB.
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Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
Sampling information regarding blanks will be recorded directly in bound logbooks (field books) and/or
referenced field forms using designated sample identification nomenclature. Standard sample labels will be
attached directly onto sample bottleware/containers immediately before or after sample collection.
Information on sample labels will include:
• Unique sample designation;
• Date and time that the sample was collected;
• Laboratory analyses that will be conducted on the sample; and
• Sample preservative (if appropriate); and
• Initials of person collecting the sample.
Completed labels will be secured to the sample container with clear tape.
4.2.4 Investigation-Derived Waste
IDW that may be generated during the groundwater plume assessment investigation will primarily include
decontamination fluids, well development and purge water, groundwater discharged during pumping tests,
soil cuttings, sampling containers, and spent PPE. IDW will be managed in general accordance with EPA
Region IV procedures and relevant state and federal regulations and guidelines. Decontamination fluids
used during sampling will consist of potable and distilled rinse water, solutions containing laboratory-grade
detergent (e.g., Alconox® or Liquinox®). Decontamination fluids will be contained in appropriately labeled
drums and characterized to determine disposal options. Soil cuttings from borings and well installation
activities as well as development water will be contained in appropriately labeled drums and characterized
to determine disposal options. Disposable equipment, used PPE, and other Site trash will be collected and
disposed as non-hazardous materials. Drums and other waste containers will be labeled with relevant
information including contents, date of generation, and generator. Disposal of IDW will occur after the
contents have been adequately characterized by an appropriate off-site facility.
It is anticipated that groundwater generated during pumping tests will be treated on-site and discharged
with permission from the City of Statesville to an on-site sewer line for disposal at the Statesville POTW as
described earlier.
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4.3 Anticipated Schedule
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
It is anticipated that groundwater plume delineation activities will begin in Spring 2009 commencing with the
surface geophysical survey and MIP investigation. Once initiated, it is anticipated that proposed
investigation work tasks will be accomplished within the general timeframes presented in the schedule
below. Note that the timing of activities will be dependent upon several factors including regulatory
approval and decisions regarding discretionary corporate expenditures.
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5.0 REFERENCES
Groundwater Plume Assessment Work Plan
FCX (Statesville) Supertund Site (OU3)
Statesville, North Carolina
American Petroleum Institute, 2003. Groundwater Remediation Strategies Tool. Publication 4730.
December 2003.
Annable, M.D., Hatfield,K, Cho, J., Klammler, H., Parker, B., Cherry, J.A., and Rao, P.S.C.,, 2005.
Field-Scale Evaluation of the Passive Flux Meter for Simultaneous Measurement of Groundwater
Contaminant Fluxes. Environmental Science and Technology. Accepted for Publication July 2005,
Brown & Caldwell, 2004. Quality Assurance Project Plan, Statesville FCX Superfund Site
Operable Unit (OU) 3, Statesville, North Carolina.
Butler, J.J., Jr., 1998. The Design, Performance, and Analysis of Slug Tests. Lewis Publishers,
CRC Press, Boca Raton, Florida.
Cedegren, H,R, 1989, Seepage, Drainage, and Flow Nets, Third Edition. John Wiley & Sons,
New York, NY.
Cooper, H.H., Bredehoeft, J.D., and Papadopulos, I.S., 1967. "Response of a Finite-Diameter Well
to and Instantaneous Charge of Water", Water Resources Research, 3(1 ), 263.
Hantush, M.S., 1966. Analysis of Data from Pumping Tests in Anisotropic Aquifers. Journal of
Geophysical Resources, Volume 71, p, 421 -426,
Hatfield, K., Annable, M., Cho, J,, Rao, P.S.C., and Klammler, H., 2004. A direct Passive Method
for Measuring Water and Contaminant Fluxes in Porous Media. Journal of Contaminant
Hydrology, Volume 75, p. 175-181.
ITRC, 2004, Technical and Regulatory Guidance for Using Polyethylene Diffusion Bag Samplers
to Monitor Volatile Organic Compounds in Groundwater.
Kruseman, G.P. and NA DeRidder, 1983. Analysis and Evaluation of Pumping Test Data.
International Institute for Land Reclamation and lmprovemenUILRI. AA Wageningen, The
Netherlands.
United States Environmental Protection Agency, 1996. Groundwater Issue, Low-Flow (Minimal
Drawdown) Ground-Water Sampling Procedures. EPA/540/S-95/50.
URS, 2008. Conceptual Site Model and Data Gap Analysis, Statesville FCX Superfund Site
Operable Unit (OU) 3, Statesville, North Carolina.
URS, 2009, in preparation. Groundwater Fate and Transport Model Work Plan, Statesville FCX
Superfund Site Operable Unit (OU) 3, Statesville, North Carolina.
Vroblesky, , DA, 2001 a. User's Guide for Polyethylene Diffusion Bag Samplers to Obtain Volatile
Organic Compound Concentrations in Monitoring Wells.' Part 1. Deployment, Recovery, Data
Interpretation, and Quality Control and Assurance. United States Geological Survey Water
Resources Investigation Report 01-4060.
Vroblesky,, DA, 2001b. User's Guide for Polyethylene Diffusion Bag Samplers to Obtain Volatile
Organic Compound Concentrations in Monitoring Wells: Part 2. Field Tests. United States
Geological Survey Water Resources Investigation Report 01-4061.
URS Corporation 5-1 April 28, 2009
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Area Description
Area 1 North
• mixed residential and commercial neighborhood
• encompasses the Site itself as well as residential
neighborhoods along Waverly Place, Wendover Road
(between Waverly Place and Ferndale Drive), and
Birchcrest Drive east of Waverly Place, includes the
sections of Melviney, Reid, and Yadkin Streets west
of Phoenix Street.
Area 1 South
• densely wooded, southern portions of Area 1
(immediate northwest of the Site)
• Northern Surface Water Drainage extends through this
wooded area.
Area 2
• residential community
• south of West Front Street, north of East Garner
Bagnal Boulevard, neighborhoods east of Woodlawn
Avenue, west of Phoenix Street, including those along
Newlon Drive.
• roads with heavy traffic, areas between single-family
homes are reportedly densely wooded.
Area 3
• commercial property
• encompassed by Phoenix Street, Miller Street, West
Front Street, and Yadkin Street, includes Piedmont
Street between Phoenix Street and Miller Street.
Area 4
• north of the Site between the quarry and Interstate 40 .
URS Corporation
TABLE 2
SUMMARY OF GEOPHYSICAL INVESTIGATION
FCX STATESVILLE SUPERFUND SITE
STATESVILLE, NORTH CAROLINA
Estimated
Depth to Seismic ERi Seismic Rationale Bedrock Refraction Reflection
(ft bgs)
• combination of two methods provides
20 to 70 X X added ccnfidence in mapping depth to
bedrock and identifying potential fracture . zones .
• to evaluate depth lo bedrock and
70 lo 120 X X delineate suspected deep fracture
lineaments.
• lo evaluate depth lo bedrock and
delineate suspected fracture lineaments. 65 (N) to X X • no seismic surveying because of heavy 100 (S) traffic along the roads and limited remote
site access.
• to evaluate depth to bedrock.
• less geologic information is available
60 lo 70 X from this area compared to Areas 1 and
2 and will be included in the domain of
the numerical flow model.
• lo provide stratigraphic information
to be including depth to bedrock in an area
determined X anticipated to be in the domain of the
numerical groundwater flow model
•
•
•
•
•
•
•
•
----
Comments
7 transect lines, -3,250 linear feet
g transect lines, -7,260 linear feet
seismic refraction not likely to achieve to
adequate depth because of potential
limitations on the types of energy sources
that can be used as well as Site physical
constraints
3 transect lines, -2,010 linear feet
18 transect lines, -6,540 feet
transect lines are spaced approximately
100 feel apart because the survey
objective in Area 3 involves identifying
potential low points along the bedrock
surface.
1 transect line, -800 feet
data will be used to locate piezometers
used to assess hydraulic head near the
quarry for the development of the
numerical groundwater flow model.
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Well Cluster/
Well Locations Description
Plume Delineation Wells
Near field cluster located along the axis of
A the Northern Plume near the north end of
the Burlington Industries Property.
Well cluster located along Phoenix Street
B between Melviney and Reid Streets
northeast of Burlington Industries Facility.
C Well cluster located off Weinig Street
northwest of Burlington Industries Facility.
D Far-field cluster to define downgradient
extent of Northern Plume
Transition zone/shallow bedrock well
E couplet located near intersection of
Woodlawn Drive with West Front Street.
Transition zone/shallow bedrock well
F couplet located near intersection of
Newton Drive with West Front Street.
Shallow bedrock monitoring well located
G along south side of 214 Phoenix Street
adjacent to Piedmont Street.
Far-field clusters located adjacent to
Hand I Gregory Road or along north side of
Interstate 40 (if needed).
Suppfementaf Wells to be Installed to Support Pumping Tests
A 4-inch diameter pumping well and four 2
Saprolite Pumping inch diameter observation well couplets
Test will be installed near location MP-17 and N
1 injection well W-72.
A 4-inch diameter pumping well and four 2
Transition Zone inch diameter observation we!ls installed
Pumping Test near location IW-St and N-1 Injection we!I
W-72.
Shallow Bedrock A 4-inch diameter pumping well and three
Pumping Test 2-inch diameter observation wells installed
near location IW-3.
Table 3
Proposed Supplemental Well Locations and Rationale
FCX Statesville Superfund Site
Statesville, North Carolina
Rationale and Purpose
;
1
scr~jned
1
zonj
SS DS TZ SB DB Basis for Location
To delineate the vertical concentration distribution within the plume and to assess the potential
concentration of PCE in potentially significant fracture zones that could be facilitating off~site ✓ ✓ ✓ ✓ ✓ Seismic Survey and Electrical Resistivity Imaging (ERi) survey results. transport of PCE'. Wells will also provide hydraulic characteristics of saprolite, transition zone
material, and fractured bedrock to sunnort a nredictive nroundwater fate and transnort model.
Wells intended to define the eastern edge of the Northern Plume and to provide a sentinel well Seismic survey, groundwater now direction and existing concentration location to assess the stability of the east side of the plume. Wells will also provide hydraulic ✓ ✓ ✓ ✓ distribution in saprolite, transition zone, and fractured bedrock suggests that characteristics of saprolite, transition zone material, and fractured bedrock to support a location B is cross gradient of plume. oredictive nroundwater fate and transnort model.
We!!s intended to define the western edge of the Northern Plume and to provide a sentinel well Seismic survey, groundwater now direction and existing concentration location lo assess the stability of the west side of the plume. Wells will also provide hydraulic ✓ ✓ ✓ ✓ distribution in saprolite, transition zone, and fractured bedrock suggests that characteristics of saprolite, transition zone material, and fractured bedrock to support a location C is cross gradient of plume. oredictive aroundwater fate and transoort model.
Wells intended to _define the downgradient extent of the Northern Plume. Wells will also provide
hydraulic characteristics of saprolite, transition zone material, and fractured bedrock to support a ✓ ✓ ✓ ✓ ✓ Seismic and ERi survey, MIP/CPT Investigation results, and groundwater How
direction. predictive groundwater fate and transport model.
Wells intended to define the western edge of the Sorthern Plume and to provide a sentinel well Seismic survey, groundwater now direction and existing concentration location to assess the stability of the west side of the plume. Wells will also provide hydraulic ✓ ✓ distribution in saprolite, transition zone, and fractured bedrock suggests that characteristics of saprolite, transition zone material, and fractured bedrock to support a location Eis cross gradient of plume. oredictive aroundwater fate and transoort model.
Wells intended to define the eastern edge of the Sorthem Plume and to provide a sentinel well Seismic survey, groundwater How direction and existing concentration location to assess the stability of the east side of the plume. Wells will also provide hydraulic ✓ ✓ distribution in saprolite, transition zone, and fractured bedrock suggests that characteristics of saprolite, transition zone material, and fractured bedrock to support a location Fis cross gradient of plume. oredictive oroundwater fate and transoort model.
Well is intended tO assess whether a deep bedrock well identified in the Conceptual Site Model Seismic survey, groundwater How direction and existing concentration
as being located along Piedmont Street could have induced the movement of impacted ✓ ✓ distribution in saprolite, transition zone, and fractured bedrock suggests that
groundwater east of the facility. location Fis cross gradient of plume.
Impacted bedrock groundwater may extend beyond impacts in saprolite due to lower Wells to be installed if impacts identified in bedrock at location D at retardation, potentially greater advective transport, and increased hydraulic gradients in bedrock ✓ ✓ ✓ ✓ ✓ concentrations an order or magnitude greater than current groundwater due to dewatering of the quarry. Wells would he!p define downgradient extent of Northern standard or greater. Plume and influence of nuarrv on nlume location.
Wells will be used to monitor water level drawdown and recovery during a pumping test to Location is proximal to the core of the plume and thus, pumping at this
estimate hydraulic properties, anisotropy, and boundary conditions affecting the saprolite. Data location is not likely to cause spreading of the plume into unimpacted areas.
will be used to support the development of a predictive groundwater fate and transport model to ✓ ✓ Monitoring well MP-17 is proximal lo the location and can be used as an
assess the effectiveness of the existing remedy and/or alternative appoaches in meeting observation well. Location is in an area that minimizes the potential for
nroundwater cleanu" "Oals established in the Record of Decision. induced rechame from surface water.
We!ls will be used to monitor water level drawdown and recovery during a pumping test to Location is proximal to the core of the plume and thus, pumping at this
estimate hydraulic properties, anisotropy, and boundary conditions affecting the transition zone. location is not likely to cause spreading of the plume into unimpacted areas.
Data will be used to support the development of a predictive groundwater fate and transport ✓ Monitoring well lW-5t is proximal to the location and can be used as an
observation well. location is in an area that minimizes the potential for model to assess the effectiveness of the existing remedy and/or alternative appoaches in induced recharge from surface water. Observation wells for saprolite pumping meeting groundwater cleanup goals established in the Record of Decision. test are co-located in this area and will be used to assess
Wells will be used to monitor water level drawdown and recovery during a pumping test to location is proximal to the core of the plume and thus, pumping at this
estimate hydraulic properties and boundary conditions affecting shallow bedrock. Data will be location is not likely to cause spreading of the plume into unimpacted areas.
used to support the development of a predictive groundwater fate and transport model to assess ✓ Monitoring well lW-3 is proximal to the location and can be used as an
the effectiveness of the existing remedy and/or alternative appoaches in meeting groundwater observation well. Location is in an area that minimizes the potential for
cleanu" "Oals established in the Record of Decision. induced rechame from surface water.
Supplemental Wells to be Installed to Support Mass Flux Measurements
W-101
W-61i
W-85i
Notes:
URS Corporation
Transition Zone Well at W-105/I cluster
Shallow bedrock well paired with N-1 well
W-61
Shallow bedrock well paired with N-1 well
W-/JS
SS = Shallow Saprolite
DS = Deeper Saprolite
Provide mass flux data from transition zone near east end of N-1 transect.
Provide groundwater Hux and mass flux data in bedrock across N-1 transect
Provide groundwater flux and mass Hux data in bedrock across N-1 transect
SB= Shallow Fractured Bedrock
DB = Deeper Competent Bedrock
Tl= Transition Zone (partially weathered rock)
✓ Near east end of plume, no transition zone well
✓ Improve resolution of mass Hux estimate in bedrock
✓ Improve resolution of mass flux estimate in bedrock
Page 1 of 1
Basis for Selection of
Well Screen lnterval(s) Well Use
Visual inspection of soil samples collected with a Groundwater sampling, hydraulic testing, and water levels.
splitspoon, borehole geophysical results, existing Concentration data will help delineate vertical location of the plume
analytical data, and packer testing in bedrock and geologic controls on plume location and migration (i.e., of
boreholes. transition zone bedrock tonrviraohv and fracture zonesl.
Visual inspection of soil samples collected with a Groundwater sampling, hydraulic testing, and water levels. Bedrock splitspoon, existing analytical data, inspection of groundwater samples collected for analysis of PCE, TCE, cis-DCE, bedrock cores, and packer testing in bedrock and VG during packer testing. boreholes. ·
Visual inspection of soil samples collected with a Groundwater sampling, hydraulic testing, and water levels Bedrock splitspoon, existing analytical data, inspection of groundwater samples collected for analysis of PCE, TCE, cis-DCE, bedrock cores, and packer testing in bedrock and VC during packer testing. boreholes.
Groundwater sampling, hydraulic testing, and water levels.
Visual inspection of soil samples collected with a Concentration data will help delineate vertical location of the plume
splitspoon, borehole geophysical results, existing and geologic controls on plume location and migration (i.e., of
analytical data, and packer testing in bedrock transition zone, bedrock topography and fracture zones). Bedrock
boreholes. groundwater samples collected for analysis of PCE, TCE, cis-DCE,
and VG durinn nacker testinn.
Visual inspection of soil samples collected with a Groundwater sampling, hydraulic testing, and water levels. Bedrock splitspoon, existing analytical data, inspection of groundwater samples collected for analysis of PCE, TCE, cis-DCE, bedrock cores, and packer testing in bedrock and VG during packer testing. boreholes.
Visual inspection of soil samples collected with a Groundwater sampling, hydraulic testing, and waler levels. Bedrock splitspoon, existing analytical data, inspection of groundwater samples collected for analysis of PCE, TCE, cis-DCE, bedrock cores, and packer testing in bedrock and VC during packer testing. boreholes.
Visual inspection of soil samples coltected with a Groundwater sampling, hydraulic testing, and water levels. Bedrock splitspoon, existing analytical data, inspection of groundwater samples collected for analysis of PCE, TCE, cis-DCE, bedrock cores, and packer testing in bedrock and VC during packer testing. boreholes.
Borehole geophysical results, packer testing in bedrock Groundwater sampling, hydraulic testing, and water levels. Bedrock
boreholes, and discrete groundwater sampling results groundwater samples collected for analysis of PCE, TCE, cis-DCE,
from fracture zones. and VC.
Existing understanding of thickness of saprolite from Monitor drawdown and recovery during an approximately 72 hour
nearby wells. pumping test.
Existing understanding of thickness of transition zone Monitor drawdown and recovery during an approximately 72 hour
from nearby wells. pumping test.
Observation of fractures in rock cores and fracture Monitor drawdown and recovery during an approximately 72 hour
yield. pumping test.
WeU log for W-10i Mass Hux and groundwater Hux measurement and groundwater
monitorirv,
Borehole geophysical results, packer testing in bedrock Mass flux and groundwater flux measurement and groundwater boreholes, and discrete groundwater sampling results
from fracture zones. monitoring
Borehole geophysical results, packer testing in bedrock Mass flux and groundwater flux measurement and groundwater boreholes, and discrete groundwater sampling results
from fracture zones. monitoring
O.\Project"LEI paso. Stateville\A. Admnistra:ive F~es\A 3 Project Managemenl\A Jg Work PlanslGW Plume investigation\Tallles 3 4
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Well Cluster Screened
Location Well Type Unit
Wells Installed to Facilitate Delineation and Plume Stability Assessment
A MW ss
MW OS
MW TZ
MW SB
MW DB
B MW ss
MW OS
MW TZ
MW SB
C MW ss
MW OS
MW TZ
MW SB
D MW ss
MW OS
MW TZ
MW SB
MW DB
E MW TZ
MW SB
F MW TZ
MW SB
G MW SB
H (if needed) MW SB
MW DB
I (if needed) MW SB
MW DB
Wells Installed to Support Pumping Test
Saprolite Pumping Test Pumping Well Saprolile
Observation Wells -Shallow Saprolite ss
Observation Wells -Deeper Saprolite OS
Transition Zone Pumping Test Pumping Well TZ
Observation Wells TZ
Shallow Bedrock Pumping Test Pumping Well SB
Observation Wells SB
Wells Installed to Support Mass Flux Estimates
W-101 MW TZ
W-61i MW SB
W-85i MW SB
Notes:
Table 4
Estimated Well Construction Specifications
Groundwater Plume Assessment
FCX Statesville, North Carolina Superfund Site (OU3)
Statesville, North Carolina
Soil Samples for
Lithologic Well
Drilling Classification and Diameter
Methodology Screening for voes (inches)
Hollow-stem augers or Rotosonic N 2
Hollow-stem augers or Rotosonic N 2
Hollow-stem augers/Case and Wash or Rotosonic y 2
Air-rotary or Rotosonic Soil Cores may be Collected, 2
Air-rotary or Rotosornc Not for Screening 2
Hollow-stem augers or Rotosonic N 2
Hollow-stem augers or Rotosonic N 2
Hollow-stem augers/Case & Wash or Rotosonic N 2
Hollow-stem augers/Case & Wash/Rotosonic/HQ core y 2
Hollow-stem augers or Rotosonic N 2
Hollow-stem augers or Rotosonic N 2
Hollow-stem augers/ Case & Wash or Rotosonic N 2
Hollow-stem augers/Case & Wash/Rotosonic/HQ core y 2
Hollow-stem augers or Rotosonic N 2
Hollow-stem augers or Rotosonic N 2
Hollow-stem augers/ Case & Wash or Rotosonic y 2
Air-rotary or Rotosonic Soil Cores may be Collected, 2
Air-rotary or Rotosonic Nol for Screening 2
Hollow-stem augers or Rotosonic N 2
Hollow-stem augers/Case & Wash/Rotosornc/HQ core y 2
Hollow-stem augers or Rotosonic N 2
Hollow-stem augers/Case & Wash/Rotosonic/HQ core y 2
Hollow-stem augers/Case & Wash/Rotosonic/HQ core y 2
Air-rotary or Rotosonic y 2
Air-rotary or Rotosonic 2
Air-rotary or Rotosonic y 2
Air-rotary or Rotosonic 2
Hollow-stem augers N 4
Hollow-stem augers N 2
Hollow-stem augers N 2
Hollow-stem augers/Case and Wash/Rotosonic y 4
Hollow-stem augers y 2
Air Rotary N 4
Air Rotary or Rotosonic Soil Cores may be Collected; 2 Not for Screening
Hollow-stem augers/Case and Wash/Rotosonic N 2
Air-Rotary or Rotosonic Soil Cores may be Collected; 2 Not for Screening
Air-Rotary or Rotosonic Soil Cores may be Collected; 2 Not for Screening
1. Screen slot size to be determined based upon grain-size distribution data. Screen will be continuous slot type
Screen
Slot Estimated
Size Depth
(inches) (ft bgs)
0.010 30
0.010 55
0.010 110
0.010 See Note 2
0.010 250
0.010 40
0.010 60
0.010 80
0.010 130
0.010 50
0.010 70
0 010 120
0.010 150
0.010 30
0.010 60
0.010 95
0.010 See Note 2
0.010 280
0.010 60
0.010 120
0.010 65
0.010 120
0.010
0.010 See Note 2
0,010 265
0 010 See Note 2
0.010 265
See Note 1 55
0.010 45
0.010 55
See Note 1 65
0.010 62.5
See Note 1 120
0.010 120
0.010 53
0.010 130
0.010 130
2. Screen intervals will be based upon borehole geophysical logging and packer testing. Depending on number of fractures, multiple zones may be screened in rock with West Bay System or multichannel tube. Will require only one borehole.
3. Screen interval will be based upon observations of recovered rock core and packer test results
MW= Monitoring well used primarily for groundwater sampling and water level observations. Wells screened in saprolite and transition zone will also be used for single well hydraulic testing.
SS = Shallow saprolite
OS = Deep saprolite
TZ = Transition zone/partially weathered rock
SB = Shallow fractured bedrock.
DB = Deeper competent bedrock.
Proposed
Screen
lnterval1
(ft bgs) Well Type
20 to 30 Conventional PVC
45 to 55 Conventional PVC
10010110 Conventional PVC
See Note 2 West Bay or Multichannel Tube
See Note 2 West Bay or Multichannel Tube
30 to 40 Conventional PVC
50 to 60 Conventional PVC
70 to 80 Conventional PVC
See Note 3 Conventional PVC
40 to 50 Conventional PVC
60 to 70 Conventional PVC
110to120 Conventional PVC
See Note 3 Conventional PVC
15 to 30 Conventional PVC
SO to 60 Conventional PVC
85 to 95 Conventional PVC
See Note 2 West Bay or Multichannel Tube
See Note 2 West Bay or Multichannel Tube
50 to 60 Conventional PVC
See Note 3 Conventional PVC
55 to 65 Conventional PVC
See Note 3 Conventional PVC
See Note 3 Conventional PVC
See Note 2 West Bay or Multichannel Tube
See Note 2 West Bay or Multichannel Tube
See Note 2 West Bay or Multichannel Tube
See Note 2 West Bay or Multichannel Tube
30 10 55 Conventional PVC
30 to 45 Conventional PVC
50 to 55 Conventional PVC
55 to 65 Conventional PVC
57.5 to 62.5 Conventional PVC
See Note 3 Conventional PVC
See Note 3 Conventional PVC
43 to 53 Conventional PVC
See Note 2 Openhole converted to PVC monitoring weU after mass flux measurement
See Note 2 Openhole converted to PVC monitoring well after mass flux measurement.
Well depths and screen intervals estimated from interpolation of existing data Actual depths and screen intervals may change based upon conditions encountered during drilling, particularly al more distant locations from the Site where there is no nearby borings or wells (e.g., location C, D. H, and I)
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0 2000
SCALE, FEET
SOURCE:
USGS 7.5-MINUTE TOPOGRAPHIC MAP OF THE
STATESVILLE WEST, NORTH CAROLINA QUADRANGLE
DATED 2002. 10 FOOT CONTOUR INTERVAL.
4000
PROJECT NO: 39460238 CLIENT: EL PASO mu::
JSH SCALE: AS SHOWN
APPROVED; LJF DATE: 3/18/09
DRAWN: LRH Fili No: STATESVILLE
PROJECT: STATESVILLE
FCX SUPERFUND SITE
STATESVILLE, NC
SITE LOCUS
FIGURE NO:
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LEGEND
10----PHREATIC SURFACE CONTOUR IN SAPROLITE
(FEBRUARY 2008) -DASHED WHERE INFERRED.
SEE FIGURE 2 FOR WELL LOCATIONS AND
GROUNDWATER ELEVATIONS USEO TO DEVELOP
CONTOURS
INFERRED FLOW DIRECTION
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tc
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RAILROAD LINE
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PROJECT LOC~TION: STATESVILLE, NORTH CAROLINA
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PROJECT NO.: FILE NAME:
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WELL USED TO DEVELOP iSOCONCENTRATION
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10----TETRACHLOROETHENE !SOCONCENTRATION
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GRAB SAMPLE LOCATIONS
USED
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NO (60.6) TETRACHLOROETHENE NOT DETECTED
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EL PASO NATURAL GAS CORPORATION
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LEGEND
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REV DATE
North
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URS Corporation
1 1 5 Water Street, Suite 3
Hallowell, ME 04347
Tei: 207.623.9188
Fax : 207.622.608::,
www.urscorp,com
FCX BLDG.
PROJEC1 NAME:
PROJECT LOCATION:
CLIENT:
PROJECT NO,:
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SCALE, FEET
STATESVILLE, NORTH CAROLINA
EL PASO NATURAL GAS CORPORATION
FILE NAME:
39460238 STATESVILLE fig 2-10 plume del.dwg
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LEGEND
WELL
MP -MONITORING PROBE FOR SOIL VAPOR EXTRACTION/AIR SPARGE WELL,
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SOIL BORINGS
EW -SOIL VAPOR EXTRACTION WELL,
SAPROUTE (RED/BROWN SILT/CLAY, SAND)
TRANSITION ZONE (GRAY, TAN, GREEN SILT/SAND/GRAVEL/ROCK FR/'.GMENTS)
BEDROCK
GEOLOGIC CONTACf
DASHED WHERE INFERRED
TETRACHLOROETHENE CONCENTRATION IN SOIL
MICROGRAMS PER KILOGRAM
GROUNDWATER PHREATIC SURFACE MARCH 2007
921 --GROUNDWATER EQUIPOTENTIA.L CONTOURS (10' CONTOURS, FEET MSL)
1000--INFERRED TETRACHLOROETHENE iSOCONTOUR IN SOIL
IN MICROGRAMS PER l<ILOGRAM
15200!
INFERRED GROUNDWATER FLOW DIRECTION
TETRACHLOROETHENE CONCENTRATIONS IN GROUNDWATER
IN MICROGRAMS PER LITER
1000--INFERRED TETRACHLOROETHENE ISOCONTOUR IN GROUNDWATER
IN MICROGRAMS PER LITER (MARCH 200 7)
s SHALLOW -SAPROLITE WELL
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INTERMEDIATE ZONE WELL IN FRACTURED BEDROCK
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MEAN SEA LEVEL
NO WATER LEVEL MEASUREMENT. MARCH 2007
CURRENT UNDERSTANDING OF
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IMPACTS
SCALE: DATE:
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STAMP:
DESIGN: JSH URS Uf~S Corporati on
DRAWN:
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CHECKED: PBL
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Fox: 207.622.6085
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PROJECT NAME: FCX SUPERFUND SITE
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CLIENT:
EL PASO NATURAL GAS CORPORATION
PROJECT NO.: FILE NAME: SCALE:
39460238 STATESVILLE fig 2-10 plume de!.dwg AS SHOWN
10------
LEGEND
UT!LITY POLE
UGHT POLE
FENCE
RAILROAD
LIMITS OF PLUME
BEDROCK CONTOURS
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I I AREA 1 SOUTH SEISMIC REFLECTION AND ERi
I I AREA 2 SEISMIC REFRACTION AND ERi
I I AREA 3 SEISMIC REFRACTION
I I AREA 4 SEISMIC REFRACTION
PROPERTY BOUNDARY
PROPOSED GEOPHYSICAL
INVESTIGATION LOCATIONS
DATE:
i/26/09
SHEET 1 OF X
FIGURE NO.:
7 I
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STAMP: ISSUED FOR DATE: DESIGN: JSH URS URS Corporation
PRELl,AINARY 11 5 Water Street, Suite 1/26/09 DRAWN: LRH Hallowel l, ME 04347
APP ROVAL Tel: 207.623,9188 CHECKED: PBL Fax: 207,622.6085
RE'✓ DATE UESCRIPTION CONS-RUCTION APPROVED: LJF
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PROJECT NAME:
3 PROJECT LOCA:flON:
CLIENT:
PROJECT NO.:
NOTE:
LOCATIONS OF ROADS AND LOT LINES
ARE APPROXIMATE
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PROPOSED MEMBRANE INTERFACE
INVESTIGATION LOCATIONS
150 300
SC,<\LE, FEET
FCX SUPERFUND SITE SHEET TITLE:
STATESVILLE, NORTH CAROLINA
EL PASO NATURAL GAS CORPORATION
PROPOSED MEMBRANE INTERFACE
PROBE INVESTIGATION LOCATIONS
39460238
FILE NAME: I SCALE:
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DATE:
1/26/09
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FIGURE NO.:
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GEOPHYSICAL INVESTIGATION.
ISSUED FOR: DATE: DESIGN:
PRELI ,1 I NARY 01/26/09 DRAWN :
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Ho ilo well, ME 04347
Tel: [phone]
Fax: [phone]
www .u rscorp .com
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PROJECT NAME:
PROJECT LOCATiON:
CLIENT:
PROJECT NO,:
0 120 240
SCALE, FEET
FCX SUPERFUND SITE
STATESVILLE , NORTH CAROLINA
El PASO NATURAL GAS CORPORATION
FILE NAME:
3946023!3 STA.TESVlLLE fig 2-10 plume deLdwg
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LEGFND
EXISTING WELL
PROPOSED INITIAL MONITORING WELL
PROPOSED SUPPLEMENTAL WELL
NEt/ BEDROCK WELL
NEW TRANSITION ZONE WELL
SUPPLEMENTAL PUMPING TEST WELL
PASSIVE FLUX METER WELL LOCATIONS
--PLUME BOUNDARY
TOPOGRAPlcHC CONTOUR
LIGHT POLE
UTILITY POLE
-PERIMETER FENCE LINE
------PROPERTY LINE
-SURFACE WATER
DRAINAGE DIRECTiON
OF FLOW INDICATED BY
===== RAILROAD LINE
------TRENCH DRAIN
AR'<OWS
SHEET TiTLE:
SCALE
PROPOSED WELL, PASSIVE FLUX
METER AND PUMPING TEST LOCATIONS
DATE:
AS SHOWN 1/26/09
SHEET 1 OF X
FIGURE NO.:
9
a--
~
!SSUED FOR; DATE: DESIGN:
PREU MINARY 01/26/09 DRAWN:
APPROVAL Cf<ECKW:
REV DATE DESCRIPTION CONST RU CTION APPROVED:
' ·.I • , , , ' •
STAMP:
JSH
LRH URS
PSL
LJF
URS Corporation
115 Water Street, Suite 3
Hallowell, ME 04347
Tel: [phone]
Fox: 207.622.6085
www .urscorp.com
PROJECT NAME:
PROJECT LOCATION:
CLIENT:
PROJECT NO.:
0 120 240
SCALE, FEET
FCX SUPERFUND SITE
STATESVILLE, NORTH CAROLINA
EL PASO NATURAL GAS CORPORATiON
FILE NAME: 39460238 STATESVlLLE fig 2-10 plume ;jeLdwg
◊
*
BE1DROCK MONITORING WELLS
TO BE SAMPLED
WELL IS NOT SAMPLED, HOWEVER
HISTORICAL DATA WILL. BE INCLUDED
IN STATISTICAL TR[ND ANALYSIS
WELLS PROPOSED FOR STATISTICAL
TREND ANALYSIS
LOCATION OF PASSIVE DIFFUSER
BAG SAMPLES .
"1CHT 0 0· F L. 7 , L_
UTILITY POLE
FENCE
-, -' -PERIMETER FENCE LINE
------PROPERTY LINE
-SURFACE WATER
DRAINAGE DIRECTION
OF FLOW INDICATED BY .ARROWS
I ====== RAILROAD LINE
FLOW DIRECTION
SHEET TITLE:
SCALE:
PROPOSED GROUNDVv'ATER SAMPLINiG
LOCATIONS AND WELLS SELECTED
FOR STATISTICAL TREND ANALYSIS
DATE:
AS SHOWN i/26/09
SHEET 1 OF X
FIGURE NO.:
0