HF Lee Background Soil Tech Memo Dec 2016_20171006

TECHNICAL MEMORANDUM
Date: December 15, 2016 File: 1026.104.19
To: Ryan Czop (Duke Energy)
Cc: Kathy Webb (SynTerra)
From: Judd Mahan W�
Subject: Quantification Of Valid Background Soil Samples for Statistics Calculations — HF
Lee Enerav Complex
Proposed Preliminary Background Threshold Values (PPBTVs) for site soils will be calculated
for CAMA assessment constituents. Soil samples were collected from soil borings during the
Comprehensive Site Assessment (CSA) field activities and CSA supplement activities at the HF
Lee Energy Complex (Site) in 2015 and 2016. Table 1 provides a summary of the samples
(locations and depth intervals) which are considered for use in statistical calculations to
determine concentrations of naturally occurring (background) inorganic constituents in Site soil.
Figure 1 indicates the location of soil samples to be used for statistical calculations.
Soil samples that meet the following criteria are considered valid for use in the statistical
calculations for background concentrations:
,01 Soil sample is collected from a location that is not impacted by coal combustion
residuals or coal associated materials;
0 Soil sample is collected from a location that is not impacted by other potential
anthropogenic sources of constituents; and
E7 Soil sample is collected from the unsaturated zone, > 1 ft. above the seasonal high water
table elevation.
After review of the soil samples considering the above criteria, five samples were eliminated
from the statistical calculations. Six samples from CSA activities and one sample from a pre-
CSA assessment (September 2013) are considered suitable to be included in the statistical
evaluation. At least one on -site background soil sampling location will be identified in order to
collect an additional sample to satisfy the above criteria.
The analytical results presented in Table 1 for antimony, cobalt, selenium, and thallium present
reporting limits that are greater than the PSRG for Protection of Groundwater (POG) as revised
in October 2016. Revised laboratory reports that will provide the non -detect values and method
detection limits are in the process of being obtained from the lab.
The statistical calculation process will include a review of data to determine if outliers exist.
Professional judgment can be used to retain data that does not satisfy one or more of the valid
soil sample criteria. Likewise, professional judgement can be used to reject soil sample data
that does satisfy all valid soil sample criteria. However, the decision to retain data that does not
P:\Duke Energy Progress.1026\104. Lee Ash Basin GW Assessment\Background Summaries\ Soil\ Lee BG Soil Tech
Memo.docx

Quantification of Valid Background Soil Samples for Statistics Calculations December 15, 2016
H.F. Lee Energy Complex
Page 2 of 2
satisfy valid soil sample criteria, and the decision to reject data that satisfy valid soil sample
criteria, must be documented. A revised Background Soil Data Summary table and evaluation
of dataset sample size will be provided following review of updated analytical reports.
ATTACHMENTS: Table 1: Background Soil Data Summary
Figure 1: Background Soil Locations for Statistical Analysis
P:\Duke Energy Progress.1026\ 104. Lee Ash Basin GW Assessment\Background Summaries\Soil\Lee BG Soil Tech
Memo.docx

TABLE 1
BACKGROUND SOIL DATA SUMMARY
H.F. LEE ENERGY COMPLEX
DUKE ENERGY PROGRESS, LLC, GOLDSBORO, NC
Analytical Parameter
pH
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chloride
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Nitrate
sN)
Potassium
Selenium
Sodium
Strontium
Sulfate
Thallium
Vanadium
Zinc
Reporting Units
S.U.
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
PSRG Protection of Groundwater
NE
0.9
5.8
580
63
45
3
NE
NE
360000
0.9
700
150
270
NE
65
1
NE
130
NE
NE
2.1
NE
NE
NE
0.28
6
1200
Sample ID
CollSample
ection Date
Sample
Elevation
ft. msl
Water Table
Elevation
Analytical Results
AMW-11 (0-2)
02/10/2015
73
69.04
4.8
3290
<2.7
<2.7
15
0.19j
3.8
<0.32
62.2
<274
4.1
<2.7
2.3
3780
3.7
223
19.9
0.0045j
<0.54
1.4
<27.4
106
<2.7
<53.7
0.93
<274
<2.7
10.6
5.7
AMW-12 SB (0-2)
02/18/2015
87
80.45
5.1
1720
<1.2
1.4
6.1
0.039j
1.8j
<0.15
42.4
<297
2.4
9.9
1.2
2350
4.8
52
2.7
0.011
<0.61
0.84
<29.7
40.4j
0.89j
<60.9
0.35j
<297
0.66j
37.6
4.3
AMW-12 SB (5-6)
02/19/2015
83
80.45
5.1
2400
<1.2
4.5
8.1
0.058 j
4.8
0.082 j
74.8
<289
4.4
11.3
2.7
5850
3.5
55.3
3
0.0044 j
<0.58
0.57
<28.9
44.4 j
0.96 j
<58.1
0.69
<289
0.73 j
37.2
4.8
AMW-13 SB (0-2)
02/23/2015
67
63.82
4.5
9510
<1.3
1.8
58.3
0.94
15.5 j
<0.16
130
<312
14
17.5
13.8
16100
8
1830
377
0.05
<0.65
5.1
<31.2
722
1.4
<65.3
3.3
<312
0.84 j
94.8
27.9
AMW-16BC (0-2)
05/24/2016
111
89.40
NA
2440
<2 112
<1
9.6
<0.051
<2.6
<0.12
30.6
NA
2.2
<1
1.2
1610
NA
110
19.5
<0.0091
<0.51
1
NA
62.2
<1
<51.1
1.1
NA
<1
2.9
2.9
AMW-16BC (19-21)
05/24/2016
92
89.40
NA
6220
<2.3 N2
<1.1
14.6
<0.057
<2.8
<0.14
62.5
NA
4.2
<1.1
2
3440
NA
177
12.3
<0.0094
<0.57
2
NA
123
<1.1
<56.8
1.4
NA
<1.1
7.7
4.7
SMW-02 (Geosyntec) (20.0-20.5)
1 09/09/2013
95.8*
90.22*
NA
NA
<0A
<0.0979
NA
NA
<0.979
<0.0536
NA
NA
1.7 j
NA
1.17 j
NA
j 3.01
NA
j 9.42
<0.0116
NA
0.921 j
NA
NA
<0.117
NA
NA
NA
<0.035
NA
0.896 j
Total Count of Valid Samples
4
6
1
7
6
6
7
7
6
4
7
0
7
0
1 5
6
1 6
7
6
7
4
6
6
6
6
4
1
1
7
Prepared by: DMY Checked by: JDM
Notes:
0 Concentration or detection limit greater than PSRG Protection of Groundwater Standard
mg/kg = milligrams per kilogram NA = Not analyzed
NE = Not established
S.U. = Standard Units
j = Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit.
< = concentration not detected at or above the adjusted reporting limit.
PSRG Protection of Groundwater = NCDEQ IHSB Preliminary Soil Remediation Soil Remediation Goals Table - October 2016
= Water table elevations collected during 24 hour site -wide well gauging event on December 4, 2015.
= Water table elevations for SMW-2, AMW-16BC and AMW-17BC were collected during a well gauging event on December 13, 2016.
N2 = The lab does not hold accreditation for this parameter.
*The ground surface elevation for SMW-02 was not available. An adjacent ground surface elevation (AMW-16BC) was used to calculate the sample and water table elevations.
P:\Duke Energy Progress. 1026\104. Lee Ash Basin GW Assessment\Background Summaries\Soil\Lee Background Soil Data Summary.xlsx Page 1 of 1

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SURFACE IMPOUNDMENT BOUNDARY
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COMPLIANCE BOUNDARY
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� • PLANT SITE BOUNDARY
NOTES:
2014AERIAL ORTHOPHOTOGRAPHY OBTAINED FROM USDA NRC
GEOSPATIAL DATA GATEWAY
(https://gdg.sc.egov.usda.gov/GDGOrder.aspx).
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH
CAROLINA STATE PLANE COORDINATE SYSTEM FIPS 3200
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GRAPHIC SCALE
300 150 0 300 600
IN FEET
148 RIVER STREET, SUITE 220
GREENVILLE, SOUTH CAROLINA 29601
PH ON E 864-421-9999
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DRAWN BY: A. FEIGL DATE 12/14/2016
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PR
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P:0uke Energy Progress, 1026\00 GIB BASE DATA\HF Lee
BACKGROUND SOIL
SAMPLE LOCATIONS
H.F. LEE ENERGY COMPLEX
GOLDSBORO, NORTH CAROLINA