NC0001422_Sutton Isotope Sampling Work Plan March 2017_20170314

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DUKE
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4C ENERGY.
Ha g , Nt—, gt60Start
Halrig�i,1V� 2760
Mailing Aadreszi
P.O. Box 1551
Mail Gbde N(: 15
Hateigh, NG 27802
March 14, 2017
919-546-7863
919-546-6302(tax)
North Carolina Department of Environmental Quality
Attn: Ms. Morella Sanchez -King
127 Cardinal Di ive Extenaiuii
Wilmington, NL 284u5
RE: L.V. Siiion E,,Crgy Complex
(3roundwater Isotope Sampling Wog k Plan
Dear Ms. Sanchez -King:
Duke Energy Progress, LLC. (DEP) submits herein the Isotope Sampling Work Plan dated March 13, 2u17
for the L.V. Sutton Energy Complex. Thib wurk plan was requested by the Depar[ment of Environmental
Quality via email received on December 21, 2u1b. The sampling of listed growidwater monitoring wclb
izo eApEcied to commence later this month. It you have any questions or neeci any clarification regarding
the information provided, feel tree to coiitact me at [e-mail] or at 919 -54b -78b3
at your convenience.
jy submitted,er, E.eer
Environmental Services
cc/enc: Mi. Steven Lanier - NCDEQ
Mr. Ed Sullivan — Duke Energy
Mr. Ricky Stroupe —Duke Energy
Mr. Perry Waldrep — SynTerra Corporation
enc: L.V. Suitui, Isotope Sampling Work Plan, March 13, 2017

MEMORANDUM
Date: March 13, 2017 File: 1026.108
To: John Toepfer
Cc: Kathy Webb (SynTerra)
From: Perry Waldrep
Subject: L.V. Sutton Isotope Sampling Work Plan
WORK PLAN SUMMARY
The CSA Supplement 1 submitted to NCDEQ on August 31, 2016 recommended
additional assessment of the Upper Pee Dee formation at the L.V. Sutton Site using
isotopic analysis of boron. The proposed isotopic evaluation is designed to collect
additional groundwater and surface water isotopic data for boron (b11B), strontium
(Sr 87/Sr86), sulfur (634S) as solute, and the hydrogen (8D) and oxygen -18 (8150) of water,
to determine natural isotopic conditions and the potential relationship of saltwater
intrusion and boron concentrations within the Pee Dee Aquifer. The analysis of
Sr87/Sr56, 634S, 6D and 6180 are included to enhance the delineation of natural conditions
compared to Coal Combustion Residual (CCR) impacted groundwater.
Boron is a typical constituent of CCR management leachate and the primary constituent
of this investigation. Isotopic b11B is best analyzed in conjunction with analysis of
Sr87/SrS6 for interpreting stable isotope mixing and flow paths based on isotopic
signatures of constituent sources'. The measurement of 634S can further support
evidence of flow paths and will strengthen the results of the 611B analysisz. The 6D and
8180 in combination with other chemical and isotopic analyses will be evaluated for a
unique seawater signature to identify suspected saltwater mixing in the Pee Dee
aquifer3.
Samples will be collected for both chemical and isotopic composition from a range of
hydrogeologic environments, including locations considered to be background, source,
plume and coastal waters to assess groundwater sources and mixing of natural and
plume waters between aquifer units. Table 1-1 lists planned sample locations with
previously reported total boron, sulfate and strontium concentrations, where available,
and the anticipated volume of water to be collected for isotopic analysis. For area
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Work Plan for Additional Isotopic Assessment March 2017
L.V. Sutton Energy Complex Page 2 of 9
coastal waters where actual boron concentration data is not available, a conservatively
large volume of water will be collected to support the range of isotopic analysis
anticipated.
PREVIOUS GROUNDWATER ISOTOPIC ANALYSIS
Previous reconnaissance level analyses of 611B were performed using another analytical
method on select wells in an effort to determine the potential origin of boron detected in
the Pee Dee zone. Results showed a relationship between boron concentrations and
61113 differentiating groundwater in the Pee Dee and Surficial aquifers (Figure 1-1).
These data were used as a screening tool and not considered conclusive. However, a
few observations can be made. The b11B values from the Pee Dee formation have a
standard deviation of ± 5.0%o and are consistent with marine 611B values' of -39%0. This
pattern indicates the occurrence of boron within the Pee Dee, particularly the lower Pee
Dee, may not be associated with the ash basins and may represent salt water intrusion.
In comparison, the Surficial aquifer has lower concentrations of boron, and a larger
range which may indicate intrinsic variability, mixing, or analytical variation in these
samples of low concentration in which the 511B measurement can be less reliable using
this preliminary method of analysis. Isotopic boron values of the Surficial aquifer are
consistent with analysis of fly ash leachate in which b11B are typically negative b11B
values2f6. Note, the extremely depleted values were omitted as anomalous data.
PLANNED SAMPLE LOCATIONS
The primary area targeted for investigation is along the groundwater flow path from
the ash basin CCR source area toward distal areas horizontally and vertically. Samples
will be collected from groundwater monitoring wells (30 wells) and one off-site coastal
surface water location. Proposed groundwater sample locations are shown on Figure 1-
2.
A range of groundwater and surface water environments will be sampled with the goal
of defining end member isotopic signatures to assess the groundwaters of four
stratigraphic units (Upper and Lower Surficial, Upper and Lower Pee Dee) and the
degree of groundwater mixing between units in the area associated with the presumed
CCR impacted groundwater plume. Samples from monitoring well MW -4A; well
clusters MW -5 and MW -37, and natural surface waters from a nearby coastal location
will be used to represent background concentrations and isotopic values. The CCR
source area will be represented by data from Surficial aquifer wells ABMW-2S, ABMW-
2D, CCR -10313, CCR -103C, and CCR -103D. The isotopic values from the above
sampling locations should define the range of values for the isotopic Site investigation.
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Work Plan for Additional Isotopic Assessment March 2017
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Table 1-1
Summary of Proposed Isotope Work Plan
Well ID
Previous
Sample
Collection
Date
Previously
Analyzed
Total Boron
(Ng/L)
Previously
Analyzed
Total
Strontium
(Ng/L)
Previously
Analyzed
Total
Sulfate
(mg/L)
Filtered/
Unpreserved
Sample Volume for
Isotope Analysis
(mL)
Surface
coastal
water
-
--
--
3000
Upper Surficial Aquifer
MW -4A
01/13/2016
67
63
83
1500
MW -5A
12/01/2016
<50
<5
8
2500
MW -5B
12/01/2016
<50
8
9.5
2000
MW -37B
11/30/2016
<50
<5
7.6
2500
Lower Surficial Aquifer
Background
Wells
MW -5C
12/01/2016
<50
20
14
2000
MW -37C
11/30/2016
<50
15
7.6
2000
Lower Surficial and Upper Pee Dee Aquifer
MW-5CD
12/01/2016
1200
160
190
1500
MW-37CD
11/30/2016
74
78
18
1500
Upper Pee Dee Aquifer
MW -5D
12/01/2016
2800
211
92
1500
MW -37D
11/30/2016
142
56
5.3
1500
Lower Pee Dee Aquifer
MW -5E
12/01/2016
1260
2970
49
1500
MW -37E
12/01/2016
1410
169
82
1500
Upper Surficial Aquifer
ABMW-2S
10/18/2016
235
1730
0.23
1500
CCR -1038
12/05/2016
1430
NA
61
1500
Source
Lower Surficial Aquifer
Wells
ABMW-2D
10/18/2016
732
1500
100
1500
CCR -103C
12/05/2016
3000
NA
180
1500
Upper Pee Dee Aquifer
CCR -103D
12/05/2016
804
NA
67
1500
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Work Plan for Additional Isotopic Assessment March 2017
L.V. Sutton Energy Complex Page 4 of 9
Table 1-1
Summary of Proposed Isotope Work Plan
Well ID
Previous
Sample
Collection
Date
Previously
Analyzed
Total Boron
(N9/L)
Previously
Analyzed
Total
Strontium
(N9/L)
Previously
Analyzed
Total
Sulfate
(m9/L)
Filtered/
Unpreserved
Sample Volume for
Isotope Analysis
(mL)
Upper Surficial Aquifer
AW -5B
01/13/2016
<50
6
16
2000
AW -6B
01/13/2016
<50
47
7.7
2000
MW -23B
10/19/2016
<50
227
7.3
2000
SMW-1B
1/13/2016
175
75
68
1500
SMW-6B
01/14/2016
57
38
40
1500
Lower Surficial Aquifer
AW -5C
01/13/2016
<50
28
16
2000
MW -12
10/18/2016
974
956
95
1500
MW -23C
10/19/2016
696
695
41
1500
Plume Wells
SMW-1C
10/26/2016
355
277
110
1500
SMW-6C
01/14/2016
298
178
70
1500
Upper Pee Dee Aquifer
AW -5D
01/13/2016
334
84
15
1500
AW -6D
10/18/2016
938
86
3.3
1500
MW -23D
10/27/2016
888
90
18
1500
SMW-6D
01/14/2016
1030
107
<1
2000
Lower Pee Dee Aquifer
AW -5E
1/13/2016
1830
157
33
1500
AW -6E
10/18/2016
2500
156
110
1500
MW -23E
10/27/2016
2700
133
92
1500
Well clusters AW -5, AW -6, MW -23, SMW-1, SMW-6, and well MW -12 will be sampled
for isotopic signatures and to assess the extent of vertical mixing of CCR plume and
potential saltwater intrusion within groundwater in the four stratigraphic units.
GROUNDWATER AND SURFACE WATER SAMPLING AND ANALYSIS
Standard low -flow groundwater sample methods will be used to collect the
groundwater samples. Standard, 500 ml, preserved metals containers along with 300 ml
unpreserved sulfate containers from each location will be shipped to the Duke Energy
Analytical Laboratory for total boron, strontium, and sulfate analysis prior to initiating
the isotope analysis. The remaining sample containers (field filtered and unpreserved
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Work Plan for Additional Isotopic Assessment March 2017
L.V. Sutton Energy Complex Page 5 of 9
aliquots) will be held by SynTerra until the total metals and sulfate results are received.
Using current boron, strontium, and sulfate concentration data, sample volumes will be
calculated to provide sufficient mass to perform analysis of the isotopes, at which time
the appropriate sample volumes will be shipped to either Tetra Tech or Isotope Tracer
Technologies laboratories. Tetra Tech plans to complete the boron, deuterium, and
oxygen -18 analyses. Isotope Tracer Technologies plan to conduct the analysis for
strontium and sulfate isotopes.
The aliquots for isotope analysis will be filtered in the field using 0.45 micron filters into
non -preserved sample containers. Minimum sample volumes are presented in Table 1-
2. The anticipated volume of water to be collected is a recommendation from Tetra
Tech who is managing the isotopic analyses. Locations with concentrations anticipated
to be at or above the detection limits will require at least 500 mL of water for each
isotopic constituent, or a total of 1,500 mL sample volume (Table 1-1). Locations with
known concentrations less than the detection limit, or no data, may require additional
volume as listed in Table 1-1. For the coastal surface water sample, 3,000 mL of water
was recommended for isotope evaluation. Although, the boron concentration in
seawater is anticipated to relatively high (reported average boron concentration of 4,500
pg/kg [2]), no data for the area is available and therefore a conservative approach will
be taken with regards to sample volume of isotope analysis.
Table 1-2
Required Sample Volumes per Analysis
Constituent
Isotope
Laboratory/Analysis
Minimum Volume Required
Technique
for Analysis (mL)
Boron
611B
Tetra Tech/TIMS
500 (filtered, unpreserved)
Strontium
87Sr/86Sr
Isotope Tracer
Tech nologies/TIMS
500 (filtered, unpreserved)
Sulfate
634s
Isotope Tracer
Tech nologies/IRMS
500 (filtered, unpreserved)
Water
61), 5180
Tetra Tech Subcontractor/GSMS
25 (filtered, unpreserved)
Total Metals
--
Duke/ICPMS
500 (not filtered, preserved)
TIMS- Thermal Ionization mass spectroscopy
IRMS- Isotope -ratio mass spectrometer
ICPMS- Inductively coupled plasma mass spectrometry
GSMS-Gas source mass spectrometry
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Work Plan for Additional Isotopic Assessment March 2017
L.V. Sutton Energy Complex Page 6 of 9
ISOTOPE EVALUATION
Data evaluation will consist of comparison of isotopic signatures, identification of end -
members, discussion of suspected sources, and constructing binary mixing and dilution
curves. Mixing curves will use end -member isotopic values of the Surficial and Pee Dee
aquifer, and other end -members if identified, to identify, where possible, the percent
dilution of groundwater moving in a vertical gradient between the aquifer units.
REFERENCES
' Faure, G. The principles of Isotope Geology; Wiley: New York, NY, 1986
2 Davidson, Gregg R., and Randy L. Bassett. "Application of boron isotopes for
identifying contaminants such as fly ash leachate in groundwater." Environmental
science & technology 27.1 (1993): 172-176.
z Cook, P. G., & Herczeg, A. L. (Eds.). (2012). Environmental tracers in subsurface
hydrology. Springer Science & Business Media.
4 Mance, G, Smith, P. R, O'Donnell, A. R and Water Research Centre (Great Britain)
Proposed Environmental quality standards for list II substances in water: boron.
Water Research Centre, Marlow, Bucks, 1988.
5 Vengosh, Avner, et al. 'Boron isotope application for tracing sources of contamination
in groundwater." Environmental Science & Technology 28.11 (1994): 1968-1974.
6 Bassett, R.L. & Ed Muller, "Stable isotope data and geochemical modeling for
compliance with CCR," USWAG CCR Workshop (2017).
Project Manager
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Work Plan for Additional Isotopic Assessment March 2017
L.V. Sutton Energy Complex Page 7 of 9
FIGURES
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Work Plan for Additional Isotopic Assessment March 2017
L.V. Sutton Energy Complex Page 8 of 9
40
Backgrou
c 20 V
0
m 0
� 1
LO
-20
-40
Figure 1-1
CSA December 2015 Boron Isotope Evaluation
11
Marine water 8 B 3
10100
�`7'--0 •
Fly As`Iech
Boron (µg/L)
N e
•
i 0 \ 10000
11
43 B -19,1t6'15.8%0
• Pee Dee Aquifer 0 Surficial Aquifer
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Work Plan for Additional Isotopic Assessment March 2017
L.V. Sutton Energy Complex Page 9 of 9
Figure 1-2
Boron Isotope Sampling Locations
P:\Duke Energy Progress. 1026\108. Sutton Ash Basin GW Assessment Plan\Boron Isotopes\Isotope Sampling Work
Plan.docx

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pc a PE -SW -6D
LEGEND
Dsmw ss PLUME BORON ISOTOPE
SAMPLING LOCATION
DAB mw -2s SOURCE BORON ISOTOPE
SAMPLING LOCATION
Mwa7o BACKGROUND BORON ISOTOPE
SAMPLING LOCATION
CCR MONITORING WELL (SURVEYED)
MONITORING WELL (SURVEYED)
COMPLIANCE MONITORING WELL
(SURVEYED)
lie CAMAMONITORING WELL (SURVEYED)
BACKGROUND COMPLIANCE
MONITORING WELL (SURVEYED)
PRIVATE WATER SUPPLY WELL
ASH BASIN
COMPLIANCE BOUNDARY
HALF -MILE OFFSET FROM
COMPLIANCE BOUNDARY
:: DUKE ENERGY PROGRESS SUTTON
PLANT SITE BOUNDARY
NOTES:
1. COASTAL SURFACE WATER SAMPLE LOCATION NOT
SHOWN. 147
2.2014 AERIAL ORTHOPHOTOGRAPHY OBTAINED FROM USDA
NRCS GEOSPATIAL DATA GATEWAY c M
(haps AWING HAS usda.g ET WITH A PROJECTION
s�, Terra
3. DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH
it
' r n
A
GRAPHIC SCALE
500 250 0 500 1,000
IN FEET
148 RIVER STREET, SUITE 220
GREENVILLE, SOUTH CAROLINA 29601
PHONE [phone]
www.svnterracori).com
DRAWN BY:A. FEIGL DATE: 02/21/2017
PROJECT MANAGER: P. WALDREP
CHECKED BY: B. WYLIE
PE -SW -6E
PZ -23D
FIGURE 1-2
BORON ISOTOPE SAMPLING
LOCATIONS
L.V. SUTTON ENERGY COMPLEX
IWIr ilk
M W -4A
a
e
MW-37CD �
MW -376 MW -37D
MW -37C 'u- MW -37E
--
a
c
s
PZ -23D
FIGURE 1-2
BORON ISOTOPE SAMPLING
LOCATIONS
L.V. SUTTON ENERGY COMPLEX