Duke Energy-Allen-Low pH and Coal Pile Area Additional Assessment Work Plan_20190703

TECHNICAL MEMORANDUM
Date: July 2, 2019 File: 1026.17.12B
To: Courtney Murphy (Duke Energy)
Cc: Kathy Webb (SynTerra)
From: Chris Suttell C:Y5
Subject: Allen Steam Station — Low pH Area and Coal Pile Area Assessment Work Plan
INTRODUCTION
This technical memorandum provides a work plan for further assessment of
groundwater and soil at two areas within Duke Energy's Allen Steam Station (Allen,
Station, or Site) property. The assessment activities would support planning for
groundwater corrective action at the Site, located near Belmont in Gaston County,
North Carolina (Figure 1). The first area, the "low pH area," is located in the vicinity of
the northern portion of the retired ash basin (RAB) extending toward the main coal pile,
one of two coal piles at the Site. The second area, the "coal pile area," includes both the
main coal pile and the active coal pile and areas downgradient of the coal piles
(Figure 2).
Previous groundwater assessment indicates that flow is from west-southwest, passing
through the RAB and low pH area, toward the east-northeast and the coal piles and
Catawba River. This indicates the low pH and coal pile areas are hydraulically
connected. However, recent (2018) assessment of the coal pile area and historical
information from the low pH area indicates these areas might be separate sources of
constituents of interest (COIs) in groundwater. Most of the COIs detected in the low pH
area are not detected farther downgradient, including areas downgradient of the coal
piles. However, some COIs, such as sulfate, are detected in groundwater downgradient
of both the low pH and coal pile areas. Therefore, additional assessment of these
potential source areas is needed to optimize ongoing groundwater corrective action
planning.
Page 1 of 8

Technical Memorandum — Low pH Area and Coal Pile Area Assessment Work Plan July 2, 2019
Duke Energy Carolinas, LLC - Allen Steam Station
SynTerra
BACKGROUND
Allen is a five -unit coal-fired electricity generating facility that occupies approximately
1,009 acres of land. Commercial operations began at the Site in 1957.
In 2014, the North Carolina General Assembly passed the Coal Ash Management Act
(CAMA). CAMA requires owners of coal combustion residuals (CCR) surface
impoundments to conduct detailed assessment of groundwater and soil within and
surrounding CCR surface impoundments. Comprehensive site assessments of the Site
have identified the primary sources of CCR-related constituents in groundwater and
soil at Allen are the RAB and active ash basin.
In an April 5, 2019, letter from the North Carolina Department of Environmental
Quality (NCDEQ) to Duke Energy, NCDEQ listed and requested assessment of
additional potential sources of constituents to groundwater at Allen. All sources
hydrologically connected to the ash basins (including the ash basins) are to be assessed
and included in an updated Corrective Action Plan (CAP). The coal pile area was
included as an additional source hydrologically connected to the ash basins. Although
not specifically requested by NCDEQ, further evaluation of the low pH area is being
planned voluntarily to better understand the potential source area.
Low pH Area Background
The low pH area is an area where groundwater pH values are approximately 4
standard units (S.U.) or less, which is less than S.U.s at other Site areas. The low pH area
likely includes a wooded tract of land encompassing approximately 6 acres within the
northern portion of RAB waste boundary directly upgradient (west) of the main coal
pile. Boring logs and anecdotal groundwater quality data from an abandoned RAB
landfill site suitability observation well (OW-3) located near the center of the wooded
tract suggest coal "mill rejects" or "clinkers" might have been placed in this area.
"Clinkers" or "mill rejects" are rocks that became mixed with coal that was not
combusted as part of the power generation process. Clinkers can be rich in pyrite and
can cause low pH subsurface conditions.
The low pH conditions may be causing several COIs to solubilize and be transported
with shallow and deep groundwater at concentrations notably greater than
concentrations of COIs at other areas at the Site. Those COIs likely caused by the low
pH conditions include arsenic, beryllium, cadmium, calcium, nickel, selenium, thallium,
and zinc, which are not detected in groundwater at concentrations greater than
applicable regulatory or background values elsewhere at the Site. Notably, monitoring
wells upgradient and side -gradient of the low pH area have pH values ranging from 6
to 6.5 S.U. Concentrations of the aforementioned COIs in upgradient and side -gradient
Page 2 of 8

Technical Memorandum — Low pH Area and Coal Pile Area Assessment Work Plan July 2, 2019
Duke Energy Carolinas, LLC - Allen Steam Station SynTerra
wells are orders of magnitude lower than respective concentrations found immediately
downgradient of the low pH area. Pyrite -rich clinkers, if found to be present, might also
be the cause of sulfate concentrations in groundwater downgradient from this area.
No wells are currently installed in the aforementioned wooded tract. The pH of shallow
groundwater observed in existing monitoring wells located immediately downgradient
of the wooded tract range from approximately 3.5 S.U. to 4.2 S.U. (Figure 2).
Groundwater pH in this area is inconsistent with pH observed in ash pore water and
groundwater at most of the Site, which typically ranges from approximately 5 S.U. to 8
S.U. Therefore, additional assessment of the low pH area is needed to determine the
source of the low pH conditions and support corrective action planning.
Coal Pile Background
Coal has been stored on -Site since operations began in 1957. There are two adjacent but
separate coal storage areas. The active coal pile, located adjacent to the Catawba River,
encompasses approximately 2 acres. The main coal pile is located west of the active coal
pile and northeast of the RAB. The main coal pile encompasses approximately 15 acres.
Both coal piles are unlined and remain active. The current locations of the coal piles are
consistent with their locations throughout the operation history of the Station, but note
that the main coal pile footprint was slightly reduced in 2018 for construction of the
new holding basin (Figure 2).
In 2018, a holding basin was built between the active coal pile and the main coal pile as
part of a water redirect project. The holding basin was constructed within the eastern
footprint of the main coal pile. To facilitate construction of the holding basin, temporary
extraction wells were used to lower the water table. Extraction well pumping rates and
water levels were monitored in select wells in the vicinity of the holding basin during
construction. Results of these monitoring activities will be included in the assessment of
the coal pile in the CAP.
In 2018,12 monitoring wells (CP-01S/D through CP-06S/D) were installed around the
coal pile area as part of a coal pile assessment to characterize groundwater in shallow
and deep flow zones (Figure 2). The coal pile assessment is ongoing; however,
preliminary findings are that COI concentrations (primarily sulfate and TDS) in
groundwater greater than applicable regulatory or background values north of the CP-
01, CP-02, and CP-03 well pairs have not been fully delineated. Sulfate concentrations
are greatest near the low pH area, at well CCR-06S. Downgradient of the coal pile, at
CP-01S, sulfate concentrations are less than at CCR-06S. Farther downgradient, at CP-
02S, sulfate concentrations are greater than at CP-01S. This distribution of COI
Page 3 of 8

Technical Memorandum — Low pH Area and Coal Pile Area Assessment Work Plan July 2, 2019
Duke Energy Carolinas, LLC - Allen Steam Station
SynTerra
concentrations from the low pH area to areas downgradient of coal piles indicates the
coal piles might be an additional source of COIs, separate from the low pH area.
Additionally, sulfate concentrations are greater than applicable regulatory or
background values in the deep flow zone wells in the coal pile area; therefore,
installation of bedrock wells for assessment of COI vertical distribution is planned.
Additionally per preliminary coal pile assessment findings, some COI concentrations in
soil are greater than applicable regulatory or background values at locations
surrounding the coal piles. These COIs in soil have the potential to be secondary
sources of COIs in groundwater. Therefore, further delineation of COI concentrations in
unsaturated soils surrounding the coal pile area is also needed to support groundwater
corrective action planning.
ASSESSMENT OBJECTIVES
SynTerra's objectives for assessing the low pH area and coal pile area include the
following:
• Further characterize and delineate constituent concentrations in CCR, soil, ash
pore water, and groundwater within the northern portion of the RAB. The
characterization and delineation will support evaluation of potential source
material, such as mill rejects, that are causing low pH conditions in this area.
• Further characterize and delineate constituent concentrations in soil and
groundwater downgradient of the coal pile.
• Refine the understanding of groundwater flow direction in both the low pH area
and coal pile area.
SynTerra proposes that 21 monitoring wells to assess the low pH and coal pile areas be
installed (Figure 2). The proposed monitoring wells would include wells installed
within CCR ash pore water and groundwater within the shallow, deep, and bedrock
flow zones. Ash pore water is the interstitial fluid within CCR material. The shallow
flow zone is considered groundwater within soil and saprolite. Underlying the shallow
flow zone is the deep flow zone, which contains groundwater within partially
weathered rock (referred to as transition zone). Underlying the deep flow zone is the
bedrock flow zone, which contains groundwater in fractured, competent bedrock.
Page 4 of 8

Technical Memorandum — Low pH Area and Coal Pile Area Assessment Work Plan July 2, 2019
Duke Energy Carolinas, LLC - Allen Steam Station
SynTerra
The proposed monitoring wells would be installed using procedures and well
construction materials similar to those used at wells installed as part of other CAMA
assessment activities. Those wells were installed in general accordance with the
NCDEQ-approved Proposed Groundwater Assessment Work Plan (Rev. 1) (HDR, 2014).
During borehole installations, SynTerra will describe soil and rock cuttings. Those
descriptions will include lithology, color, and the type of ash, soil, or rock. All of the
proposed monitoring wells would be constructed in accordance with NCAC Title 15A,
Subchapter 2C, Section .0100 Well Construction Standards. All of the proposed wells
would consist of 2-inch diameter schedule 40 polyvinyl chloride flush -joint threaded
casings and prepacked well screens.
After well installation is complete, monitoring wells would be developed to remove
drilling fluids and solids that might have been introduced into the surrounding
formation and sand pack during well installation. Well development helps establish
interaction of the well with surrounding ash pore water or groundwater. The location
and elevation of each newly installed well will be determined by survey. The newly
installed wells would also be slug tested to evaluate hydraulic properties of the
groundwater flow system at each location.
Groundwater samples would be collected using low -flow sampling techniques and
following procedures outlined in the Low Flow Sampling Plan, Duke Energy Facilities, Ash
Basin Groundwater Assessment Program, North Carolina, June 10, 2015 (Duke Energy,
2015). Groundwater samples would be analyzed for constituents and parameters in
Table 1 of the Interim Monitoring Plan (IMP), with the exceptions of mercury, total
radium, and total uranium, which among other constituents, are not considered COIs at
the Site. The IMP was approved in an April 4, 2019, letter from NCDEQ to Duke
Energy.
The additional wells would be added to the IMP. However, in order to have at least two
sampling events and analytical data sets available for evaluation in the CAP, samples
would be collected at a greater frequency (less than 60 days between sampling events)
prior to submittal of the CAP. After up to three sampling events, the sampling
frequency would return to a schedule consistent with the IMP.
Page 5 of 8

Technical Memorandum — Low pH Area and Coal Pile Area Assessment Work Plan July 2, 2019
Duke Energy Carolinas, LLC - Allen Steam Station
LOW PH AREA ASSESSMENT
SynTerra
Assessment of the low pH area would include installation of investigative borings for
pH screening of solids (ash and soil) and installation of sampling and monitoring wells
for groundwater sampling and water level monitoring. The characterization and
delineation will support evaluation of potential source material, such as mill rejects, that
are causing low pH conditions in this area. Information obtained from this investigation
will supplement existing data and be evaluated for corrective action planning.
Investigative Borings and Solids Sampling
Approximately 10 investigative borings (SB-10 through SB-19) would be advanced
using direct -push technology to install the borings in the low pH area (Figure 2). Those
borings would be installed at locations that form a grid -like pattern in the wooded tract
within the north portion of the RAB (Figure 2). Borings would be terminated once the
interface between ash and soil is observed. SynTerra would collect solids from the
borings at 3- to 5-foot intervals (depending on field observations) and assess the pH of
the solids in the field by making a pH paste aliquot and measuring pH with a calibrated
pH probe. The pH paste aliquot would be made by mixing deionized water with solids
at selected intervals from each boring individually. Additional solid samples would be
collected from up to three separate intervals based on field screening results and
submitted for laboratory analysis for further characterization of the potential source
area. Those solid samples would be analyzed for the following parameters:
• pH — to assess the acidity or alkalinity of the material (soil and/or ash) and
verify field measurements recorded with the pH probe
• Acid base accounting — to determine the acid -producing and acid -neutralizing
potential of the material
• Acid volatile sulfide — to assess constituent concentrations liberated during
acidification of the material
• Inorganic and mineralogical analysis — to assess the chemical composition and
mineralogy of the material
• Synthetic precipitation leaching procedure (SPLP) — to assess the leaching
potential of the material
• Hydrous iron oxide/hydrous aluminum oxide (HFO/HAO) — to assess the
available area for constituent sorption to the material
Page 6 of 8

Technical Memorandum — Low pH Area and Coal Pile Area Assessment Work Plan July 2, 2019
Duke Energy Carolinas, LLC - Allen Steam Station
SynTerra
In addition to the samples collected from the investigation borings, SynTerra would
also collect solid samples at proposed monitoring well locations as part of well
installation activities (Figure 2). Unsaturated solid samples would be collected every 3
feet to 5 feet until the water table is encountered. The water table is estimated to occur
approximately 10 feet to 30 feet below ground surface (Table 1). To supplement data
used for the geochemical model, additional soil samples would be collected for
HFO/HAO analysis at depths that coincide with the depths in which well screen
intervals will be installed.
Solid samples from the proposed well locations would be submitted for laboratory
analysis and analyzed for inorganic constituents (Table 2). Results would be compared
to the Preliminary Soil Remediation Goal (PSRG) Protection of Groundwater (POG).
SPLP would be performed on a single unsaturated solid sample from each boring to
enable analysis of potential leaching of inorganic constituents (Table 2) from solids.
Groundwater Assessment
SynTerra proposes that monitoring well clusters be installed at five locations within the
low pH area to enable evaluation of the potential source area. The proposed source area
well clusters would consist of either two or three monitoring wells. Proposed locations
with three monitoring wells include wells installed within CCR ash pore water, the
groundwater of the shallow flow zone, and the groundwater of the deep flow zone.
Proposed locations with two morning wells include wells installed within the
groundwater of the shallow flow zone and the groundwater of the deep flow zone. The
locations of the wells would be determined based on the investigative borings pH
screening results.
SynTerra proposes that a single well cluster be installed downgradient of the low pH
area to supplement existing well clusters in the area. The proposed cluster would
consist of wells installed within groundwater of the shallow and deep flow zones. A
summary of the proposed well installations is provided in Table 1.
COAL PILE AREA ASSESSMENT
Assessment of the coal pile area would include installation of monitoring wells and soil
sampling at the proposed well locations. Water levels and groundwater samples would
be collected from the newly installed wells. The purpose of these assessment activities is
to further delineate COIs in the coal pile area to support corrective action planning.
Page 7 of 8

Technical Memorandum — Low pH Area and Coal Pile Area Assessment Work Plan July 2, 2019
Duke Energy Carolinas, LLC - Allen Steam Station
Soil Assessment
SynTerra
SynTerra would collect soil samples at proposed monitoring well locations as part of
well installation activities (Figure 2). Soil samples would be collected every 3 feet to 5
feet until the water table is encountered. The water table is estimated to occur
approximately 10 feet to 30 feet below ground surface (Table 1). To supplement
geochemical modeling data, additional soil samples would be collected below the water
table at depths that coincide with the depths in which well screen intervals will be
installed. SPLP would be performed on a single unsaturated solid sample from each
boring to enable analysis of potential leaching of inorganic constituents (Table 2) from
solids.
Groundwater Assessment
SynTerra proposes that two well clusters be installed downgradient of the existing coal
pile assessment well network (Figure 2) to further delineate COI concentrations. Each of
the proposed well clusters would consist of wells with screened intervals within
groundwater of the shallow, deep, and bedrock flow zones. SynTerra also proposes that
a single bedrock well be installed at the location of the existing CP-02 well cluster to
further delineate COIs concentrations detected in the deep flow zone (Figure 2). A
summary of the proposed well installation is provided in Table 1.
ASSESSMENT REPORTING
SynTerra would include the findings from the assessment of the low pH and coal pile
areas in the CAP to be submitted to NCDEQ at a later date.
Page 8 of 8

Technical Memorandum — Low pH Area and Coal Pile Area Assessment Work Plan July 2, 2019
Duke Energy Carolinas, LLC - Allen Steam Station
ATTACHMENTS:
SynTerra
Figure 1: Site Location Map
Figure 2: Proposed Low pH Area and Coal Pile Area Assessment Sample Locations
Table 1: Proposed Low pH Area and Coal Pile Area Assessment Monitoring Wells
and Soil Samples
Table 2: Soil Analytical Parameters
Table 1 from Interim Monitoring Program Optimization — Summary of Analytical
Parameters for Newly Installed Wells (to begin Q12019)
REFERENCES:
Duke Energy, June 10, 2015. Low Flow Sampling Plan, Duke Energy Facilities, Ash
Basin Groundwater Assessment Program, North Carolina.
HDR. (2014). Allen Steam Station Ash Basin Proposed Groundwater Assessment Work
Plan (Rev. 1), December 30, 2014
HDR. (2016a). Comprehensive Site Assessment Supplement 1— Allen Steam Station —
February, 2016.
HDR. (2016b). Comprehensive Site Assessment Supplement 2 — Allen Steam Station — August,
2016.
NCDEQ, April 4, 2019, Correspondence to Duke Energy, Subject: Response to the
Interim Monitoring Plans (IMP) for 14 Duke Energy Facilities — Modification
Request Annual Reports — Modification Request
NCDEQ, April 5, 2019, Correspondence to Duke Energy, Subject: Coal Ash
Impoundment Closures at Allen, Belews Creek, Cliffside/Rogers, Marshall, Mayo
and Roxboro Facilities
NCDEQ, May 9, 2019, Correspondence to Duke Energy, Subject: Final Comprehensive
Site Assessment and Corrective Action Plan Approvals for Duke Energy Coal
Ash Facilities
SynTerra (2018a). Comprehensive Site Assessment Update — Allen Steam Station — January,
2018. Belmont, NC.
SynTerra (2018b). Allen Steam Station Coal Pile Assessment Work Plan — January 2018.
Revised June 2018. Belmont, NC.
Page 9 of 8

Technical Memorandum — Low pH and Coal Pile Area Assessment Work Plan July 2, 2019
Duke Energy Carolinas, LLC - Allen Steam Station
ATTACHMENTS
SynTerra

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LOW pH AREA AND COAL PILE AREA
CAROLINAS
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ALLEN STEAM STATION
GASTON COUNTY, NORTH CAROLINA
GASTON DRAWN
COUNTY REVISED
BY: B. YOUNG DATE: 05/02/2019
BY: K. KING DATE: 06/25/2019
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BY: L. DRAGO DATE: 06/25/2019
MANAGER: C. SUTTEL
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LEGEND
PROPOSED LOW pH / COAL PILE ASSESSMENT
MONITORING WELL
PROPOSED LOW pH ARE ASSESSMENT
INVESTIGATIVE SOIL BORING
EXISTING MONITORING WELL EXHIBITING LOW pH
EXISTING COAL PILE ASSESSMENT WELLS
LANDFILL BOUNDARY
DORS FILLS BOUNDARIES
LANDFILL COMPLIANCE BOUNDARY
DUKE ENERGY CAROLINAS ALLEN PLANT
■ SITE BOUNDARY
NOTES:
ALL BOUNDARIES ARE APPROXIMATE.
PROPERTY BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS.
2014 AERIAL ORTHOPHOTOGRAPHY OBTAINED FROM WSP, APRIL 2014.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA STATE PLANE
COORDINATE SYSTEM FIPS 3200 (NAD83).
FIGURE 2
PROPOSED LOW pH AREA AND COAL PILE AREA
ASSESSMENT SAMPLE LOCATIONS
ALLEN STEAM STATION
BELMONT, NORTH CAROLINA

TABLE 1
PROPOSED LOW pH AREA AND COAL PILE AREA MONITORING WELLS AND SOIL SAMPLES
ALLEN STEAM STATION
DUKE ENERGY CAROLINAS, LLC, BELMONT, NC
Location ID
Estimated Depth
(feet bgs)
Soil Sample ID
(Estimated Depth Interval in feet
bgs)
Comments
Investigative Soil Borings
SB-10
32
TBD
TBD
SB-11
32
TBD
TBD
SB-12
32
TBD
TBD
SB-13
32
TBD
TBD
SB-14
32
TBD
TBD
SB-15
32
TBD
TBD
SB-16
32
TBD
TBD
SB-17
32
TBD
TBD
SB-18
32
TBD
TBD
SB-19
32
TBD
TBD
Monitoring Wells
AB-40SS
50
AB-40SB (45-46)
Soil sample from shallow well screened interval
AB-40D
80
AB-40SB (75-76)
Soil sample from deep well screened interval
AB-41S
30
AB-41SB (25-26)
Ash sample from ash pore water well screened interval
AB-41SS
50
AB-41SB (45-46)
Soil sample from shallow well screened interval
AB-41D
80
AB-41SB (75-76)
Soil sample from deep well screened interval
AB-42SS
50
AB-42SB (45-46)
Soil sample from shallow well screened interval
AB-42D
80
AB-42SB (75-76)
Soil sample from deep well screened interval
AB-43S
30
AB-43SB (25-26)
Ash sample from ash pore water well screened interval
AB-43SS
50
AB-43SB (45-46)
Soil sample from shallow well screened interval
AB-43D
80
AB-43SB (75-76)
Soil sample from deep well screened interval
AB-44SS
50
AB-44SB (45-46)
Soil sample from shallow well screened interval
AB-44D
80
AB-44SB (75-76)
Soil sample from deep well screened interval
GWA-27SB (2-3)
Near -surface unsaturated soil sample, water table —15 feet bgs
GWA-27SB (8-9)
Unsaturated soil sample, water table —15 feet bgs
GWA-27SB (13-14)
Unsaturated soil sample, water table —15 feet bgs
GWA-27S
40
GWA-27SB (35-36)
Soil sample from shallow well screened interval
GWA-27D
125
GWA-27SB (120-121)
Soil sample from deep well screened interval
GWA-27SB (2-3)
Near -surface unsaturated soil sample, water table —10 feet bgs
GWA-27SB (8-9)
Unsaturated soil sample, water table —10 feet bgs
GWA-28S
GWA-28SB (35-36)
Soil sample from shallow well screened interval
GWA-28D
GWA-28SB (65-66)
Soil sample from deep well screened interval
GWA-28BR
GWA-28SB (125-126)
Soil sample from bedrock well screened interval
GWA-28SB (2-3)
Near -surface unsaturated soil sample, water table —10 feet bgs
GWA-28SB (8-9)
Unsaturated soil sample, water table —10 feet bgs
GWA-29S
40
GWA-29SB (35-36)
Soil sample from shallow well screened interval
GWA-29D
70
GWA-29SB (65-66)
Soil sample from deep well screened interval
GWA-29BR
130
GWA-29SB (125-126)
Soil sample from bedrock well screened interval
CP-02BR
130
CP-02SB (125-126)
Soil sample from bedrock well screened interval
Prepared by: LWD Checked by: CJS
Notes:
bgs = below ground surface
— = Approximately
TBD = to be determined; based on field observations
SynTerra recommends rotosonic drilling methods for boring and well installation
Continuous cores from sonic drilling provide sufficient material for soil sampling and lithologic description.
Estimated well and soil sample depths based on data from the OW-3, GWA-6S/DA, CP-2S/D.
Number of soil samples shown is approximate. A shallower water table will result in fewer samples,deeper water table will result in additional samples.
SynTerra recommends each well screen be submerged beneath the water table and have a length of at least 10 feet
P:\Duke Energy Carolinas\17.ALLEN\XX.Low pH Area Assessment\
Table 1 - Proposed Low pH Area Assessment Monitoring Wells and Soil Samples.xlsx Page 1 of 1

TABLE 2
SOIL ANALYTICAL PARAMETERS
ALLEN STEAM STATION
DUKE ENERGY CAROLINAS, LLC, BELMONT, NC
INORGANIC COMPOUNDS
PSRG POG
UNITS
METHOD
Aluminum
110000
mg/kg
EPA 6010D
Antimony
0.9
mg/kg
EPA 6020B
Arsenic
5.8
mg/kg
EPA 6020B
Barium
580
mg/kg
EPA 6010D
Beryllium
63
mg/kg
EPA 6020B
Boron
45
mg/kg
EPA 6010D
Cadmium
3
mg/kg
EPA 6020B
Calcium
NE
mg/kg
EPA 6010D
Chloride*
NE
mg/kg
EPA 9056A
Chromium
3.8
mg/kg
EPA 6010D
Cobalt
0.9
mg/kg
EPA 6020B
Copper
700
mg/kg
EPA 6010D
Iron
150
mg/kg
EPA 6010D
Lead
270
mg/kg
EPA 6020B
Magnesium
NE
mg/kg
EPA 6010D
Manganese
65
mg/kg
EPA 6010D
Mercury
1
mg/kg
EPA 7471B or 7470A
Molybdenum
7.1
mg/kg
EPA 6010D
Nickel
130
mg/kg
EPA 6010D
Nitrate as Nitrogen*
NE
mg/kg
EPA 9056A
pH*
NE
S.U.
EPA 9045D
Potassium
NE
mg/kg
EPA 6010D
Selenium
2.1
mg/kg
EPA 6020B
Sodium
NE
mg/kg
EPA 6010D
Strontium
1500
mg/kg
EPA 6010D
Sulfate*
NE
mg/kg
EPA 9056A
Thallium low level
0.28
mg/kgmg/kg
EPA 6020B
Total Organic Carbon*
NE
mg/kg
EPA 9060A
Vanadium
350
mg/kg
EPA 6020B
Zinc
1200
mg/kgmg/kg
EPA 6010D
Prepared by: RBI Checked by: CJS
Notes•
1. Soil samples to be analyzed for Total Inorganics using USEPA Methods 6010/6020 and pH using USEPA Method 9045, as noted above.
Select soil samples will also be analyzed for leaching potential using SPLP Extraction Method 1312 in conjunction with USEPA Methods
6010/6020.
2. Analytical methods as presented were applicable as of May 6, 2019. Analytical methods are updated periodically and applied as
appropriate.
*Select constituents are not analyzed for leaching potential.
PSRG POG - Primary Soil Remediation Goals Protection of Groundwater
mg/kg - Milligrams per kilogram
S.U. - Standard Unit
P:\Duke Energy Carolinas\17.ALLEN\XX.Low pH Area Assessment\Table 2 - Soil Analytical Parameters.xlsx Page 1 of 1

TABLE 1
IMP Optimization
Summary of Analytical Parameters for Newly Installed Wells
(to begin Q1 2019)
For each of Duke Energy's 14 North Carolina facilities, new wells installed as part of the CAMA program will be
monitored quarterly. Samples from these wells will be analyzed for parameters formerly included as part of the 4th
Quarter 2018 IMP and additional constituents analyzed voluntarily. After four quarterly events, the monitoring
frequency and/or parameter list for the new wells will be re-evaluated with NCDEQ and may be reduced and/or
optimized. A summary of analytical parameters to include under this criteria is provided below.
SUMMARY OF ANALYTICAL PARAMETERS FOR NEWLY INSTALLED WELLS
Minimum CAMA Parameters per Q4 2018 IMP
(Metals are Totals)
Additional Voluntary Parameters
[Dissolved (0.45 micron filter)]
Aluminum
Mercury
Molybdenum
Aluminum
Antimony
Mercury
Molybdenum
Nickel
Alkalinity (CO3/HCO3)
Antimony
Nickel
Arsenic
Arsenic
Potassium
Barium
Phosphorus
Barium
Radium (226 + 228)
Beryllium
Potassium
Beryllium
Selenium
Boron
Selenium
Boron
Sodium
Cadmium
Silver
Cadmium
Strontium
Calcium
Sodium
Calcium
Sulfate
Chromium
Strontium
Chloride
Sulfide
Cobalt
Thallium
Chromium
Total Dissolved Solids (TDS)
Copper
Vanadium
Cobalt
Thallium
Iron
Zinc
Copper
Total Organic Carbon (TOC)
Lead
Hexavalent Chromium
Uranium (233+234+236+238)
Lithium
Iron
Lead
Total Suspended Solids (TSS)
Magnesium
IManganese
Vanadium
Magnesium
Zinc
Additional Voluntary Parameters
(Totals)
Manganese
Fluoride
Lithium
Nitrate + Nitrite
Phosphorus
Methane*
Additional Field Water Quality Parameters
A� = A
Dissolved Oxygen (DO)
Oxidation -Reduction Potential (ORP)
Redox Potential (Eh)
Turbidity
Temperature
Specific Conductance
pH
* W.H. Weatherspoon Power Plant only