2018 CAMA Annual Report 1 of 2

�� DUKE
ENERGY
April 30, 2019
North Carolina Department of Environmental Quality
Division of Water Resources
Water Quality Regional Operations Section
3800 Barrett Drive
1628 Mail Service Center
Raleigh, North Carolina 27699
Attn: Mr. Eric Rice (submitted electronically via FTP)
Re: 2018 Mayo CAMA Annual Report
Mayo Steam Electric Plant
10660 Boston Road
Roxboro, NC 27574
Dear Mr. Rice:
2500 Fairfax Road
Greensboro, North Carolina 27407
336-2154576
Enclosed you will find the 2018 CAMA Annual Report prepared by SynTerra Corporation for
the Duke Energy Mayo Steam Electric Plant. This Annual Report documents the information
required by the North Carolina Department of Environmental Quality per letter dated May 1,
2017.
If you have any questions or need any clarification regarding the information provided, feel free
to contact me at [e-mail] or at 336-215-45776 at your convenience.
Respectfully submitted,
Kimberlee Witt, PE, ME
Duke Energy, Environmental Services
cc : Eric Smith — DEQ Central Office
Steve Lanter — DEQ Central Office
Ed Sullivan - Duke Energy
Scott Davies — Duke Energy
Jerry Wylie — SynTerra Corporation
Page 1 of 1

2018 LAMA ANNUAL INTERIM
MONITORING REPORT
FOR
MAYO STEAM ELECTRIC PLANT
10660 BOSTON ROAD
ROXBORO, NC 27574
APRIL 30, 2019
PREPARED FOR:
DUKE ENERGY PROGRESS, LLC
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PREPARED BY:
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2018 CAMA ANNUAL INTERIM
MONITORING REPORT
FOR
MAYO STEAM ELECTRIC PLANT
10660 BOSTON ROAD
ROXBORO, NC 27574
APRIL 30, 2019
PREPARED FOR
DUKE ENERGY PROGRESS,. LLC
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PREPARED BY
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
EXECUTIVE SUMMARY
ES.1 Introduction
This annual report evaluates the results of groundwater monitoring performed on a
quarterly basis during the 2018 calendar year at the Mayo Steam Electric Plant (Mayo,
Plant, or Site). The Site is a coal-fired electricity -generating facility owned and operated
by Duke Energy located in Roxboro, Person County, North Carolina. Monitoring was
performed in accordance with the requirements of the Coal Ash Management Act
(CAMA) of 2014 (15A NCAC 13B .2001), and in correspondence with the North
Carolina Department of Environmental Quality (NCDEQ), and based on the Interim
Monitoring Plan (IMP) developed for the Site.
A generalized conceptual site model (CSM) for the Mayo Site is presented below. The
ash basin was constructed within a former perennial stream valley in the North
Carolina Piedmont. The following components of the hydrogeologic setting limit
constituent of interest (COI) transport in groundwater:
• Topographic ridges reflect groundwater divides on either side of the stream
valley that inhibit lateral flow side -gradient of the basin.
• Naturally occurring upward vertical groundwater gradients to the former
perennial stream limits downward migration of COIs under the basin.
• Nearly neutral hydraulic gradients within impounded ash promote horizontal
flow across the ash basin.
• The hydraulic pressure of ponded water in the ash basin drives seepage flow of
groundwater under the basin dam.
• Beyond the dam, groundwater flows upward toward Crutchfield Branch,
limiting migration of COIs to the area in close proximity to the dam.
The 2018 distribution and concentration of COIs in groundwater within the surficial,
transition zone, and bedrock flow zones are evaluated with respect to historical Site
conditions. Changes to Site conditions that occurred during 2018 that may influence
groundwater flow or quality are also discussed.
ES.2 Key Findings
Key findings of the quarterly CAMA monitoring conducted in 2018 include:
• The Ash Basin is considered the primary source of coal combustion residuals
(CCR)-related constituents in groundwater at the Site.
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
• The current distribution of COIs at the Mayo Plant are contained within the
Duke Energy property boundary with the exception being select COIs in
groundwater beyond the compliance boundary at wells MW-16S/D/BR.
• No imminent hazards to human health and safety or evidence of ecological risks
related to the ash basin have been identified.
• Groundwater flow direction is consistent with the slope -aquifer system model
common to the Piedmont Physiographic Province and is away from potential
water supply receptors located upgradient of the Site.
• The ash basin is a flow -through system with upward hydraulic gradients into the
former stream valley at upgradient ends of the basins. Hydraulic gradients are
predominantly horizontal across the basin. Hydraulic gradients are downward
in the vicinity of the ash basin dam. Upward vertical gradients occur below the
dam in the vicinity of receiving water bodies (groundwater discharge areas). This
flow -through system limits downward vertical migration of COIs into
groundwater to the areas in close proximity to the dam.
• Boron is the key indicator of groundwater migration associated with the ash
basins.
• Based on review and comparison with historical Site data, the COI plume at the
Mayo Plant appears to be stable.
ES.3 Interim Monitoring Plan Updates
Duke Energy submitted an optimized IMP to NCDEQ on March 20, 2019, which was
approved on April 4, 2019. The plan recommends adjusting the well and water quality
parameter lists to more efficiently monitor groundwater conditions at the Site. The
optimized 2019 IMP is designed to provide data associated with changes to the Site
groundwater occurrence, flow and quality as remedial efforts (e.g., ash basin decanting,
closure) are phased in.
Please note that the list of Site -specific COIs for inclusion into the Corrective Action
Plans (CAPs) is currently undergoing review using the COI management approach
presented to the NCDEQ on March 15, 2019. COIs proposed for management under the
CAP would be based on:
• Comparing constituent concentrations to regulatory standards and/or
background values
• Evaluating each constituent's relative mobility
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
• Reviewing constituent distribution in groundwater based on geochemical
conditions
• Comparing each constituent's relative concentration observed in ash pore water
to the concentration observed in groundwater
• Evaluating constituent concentration trends over time
The results of this review will be presented in the CAP and may result in proposed
modifications to the monitoring program at that time.
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
TABLE OF CONTENTS
SECTION
PAGE
EXECUTIVE SUMMARY....................................................................................................
ES-1
ES.1 Introduction............................................................................................................
ES-1
ES.2 Key Findings...........................................................................................................
ES-1
ES.3 Interim Monitoring Plan Updates.......................................................................
ES-2
1.0 INTRODUCTION.........................................................................................................1-1
1.1 Objectives and Purpose............................................................................................1-1
1.2 Site Overview and History......................................................................................1-2
1.3 Changing Site Conditions........................................................................................1-2
1.4 Regional Hydrogeology...........................................................................................1-3
1.5 Site Hydrogeology....................................................................................................1-3
1.6 Previous Reporting...................................................................................................1-5
1.7 Overview of Findings for 2018................................................................................1-6
2.0 2018 MONITORING ACTIVITIES...........................................................................
2-1
2.1 2018 Quarterly Sampling Schedule........................................................................
2-1
2.2 Changes to the CAMA Groundwater Monitoring Network ..............................
2-1
2.3 Water Level Measurements.....................................................................................2-2
2.4 Groundwater Sampling Methods...........................................................................
2-2
2.5 Laboratory Analyses.................................................................................................
2-3
2.6 Quality Control Summary (Data Validation).......................................................2-3
3.0 2018 MONITORING RESULTS.................................................................................3-1
3.1 Site -Wide Groundwater Occurrence and Flow ....................................................
3-1
3.1.1 Ash Basin Groundwater Occurrence and Flow..............................................3-2
3.1.2 Horizontal Gradients..........................................................................................3-3
3.1.3 Vertical Gradients...............................................................................................
3-3
3.1.4 Groundwater Seepage Velocity........................................................................
3-4
3.2 Data Reduction and Evaluation..............................................................................3-5
3.3 Ash Basin Water Quality........................................................................................3-10
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
TABLE OF CONTENTS (CONTINUED)
SECTION
PAGE
3.3.1 Site Conditions.................................................................................................. 3-10
3.3.2 Constituent Occurrence and Plume Status ................................................... 3-10
4.0 SUMMARY AND CONCLUSIONS.........................................................................4-1
4.1 Groundwater Occurrence and Flow......................................................................4-1
4.2 Groundwater Quality............................................................................................... 4-1
5.0 INTERIM MONITORING PLAN UPDATES......................................................... 5-1
5.1 Optimization of the Monitoring Program.............................................................5-1
5.2 2019 Monitoring and Reporting Schedule.............................................................5-2
6.0 REFERENCES................................................................................................................ 6-1
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
LIST OF FIGURES
Figure 1-1
Site Location Map
Figure 1-2
Site Map with Monitoring Well Locations
Figure 3-1
Water Level Map - Surficial Flow Zone (November 5-6 2018)
Figure 3-2
Water Level Map - Transition Zone (November 5-6 2018)
Figure 3-3
Water Level Map - Bedrock Flow Zone (November 5-6 2018)
Figure 3-4 Hydrographs
Figure 3-5 Flow Velocity Vectors and Magnitudes - Surficial Flow Zone
Figure 3-6 Flow Velocity Vectors and Magnitudes - Transition Zone Flow Zone
Figure 3-7 Flow Velocity Vectors and Magnitudes - Bedrock Flow Zone
Figure 3-8 Flow Velocity Vectors and Magnitudes through Dam
Figure 3-9 General Cross -Section A -A'
Figure 3-10 General Cross -Section B-B'
Figure 3-11 Isoconcentration Map - Geomean of Boron in Surficial Flow Zone
Figure 3-12 Isoconcentration Map - Geomean of Boron in Transition Zone Flow Zone
Figure 3-13 Isoconcentration Map - Geomean of Boron in Bedrock Flow Zone
Figure 3-14 Time Series Plots - Ash Basin (1 of 2)
Figure 3-15 Time Series Plots - Ash Basin (2 of 2)
LIST OF TABLES
Table 1-1 Monitoring Well Construction Information
Table 2-1 2018 CAMA Water Elevations
Table 3-1 Horizontal Hydraulic Gradients and Flow Velocities
Table 3-2 Vertical Hydraulic Gradients
Table 3-3 2018 Comprehensive Groundwater Quality Data
Table 3-4 Data Qualifiers and Acronyms
Table 3-5 Geometric Mean of COIs - 2018 Quarterly Data
Table 3-6 Constituents of Interest Evaluation
Table 3-7 Groundwater Background Threshold Values and Regional Background
Concentration Ranges
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
LIST OF APPENDICES
Appendix A Correspondence with NCDEQ
Appendix B Field Data and Forms
• Groundwater Sampling Forms
• Water Level Measurements
• Well Abandonment Records
• Well/Boring Logs
Appendix C Approved Low Flow Sampling Plan
Appendix D Laboratory Analytical Data (Laboratory Reports)
and Data Validation Checklists
• Q1-2018
• Q2-2018
• Q3-2018
• Q4-2018
Appendix E Optimized Interim Monitoring Plans for 2019
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
LIST OF ACRONYMS
02L
NCAC Title 15A, Subchapter 02L. Groundwater Classification and
Standards
BTV
Background Threshold Value
°C
degrees Celsius
CAMA
Coal Ash Management Act
CAP
Corrective Action Plan
CCR
Coal Combustion Residuals
COC
Chain of Custody
COI
Constituent of Interest
CSA
Comprehensive Site Assessment
CSM
Conceptual Site Model
dh/dl
hydraulic gradient
DO
Dissolved Oxygen
DQO
Data Quality Objective
DWM
Division of Waste Management
EMP
Effectiveness Monitoring Program
FGD
Flue Gas Desulfurization
ft
foot
IMAC
Interim Maximum Allowable Concentration
IMP
Interim Monitoring Plan
k
horizontal hydraulic conductivity
LRB
Lined Retention Basin
MARLAP
Multi -Agency Radiological Laboratory Analytical Protocols
mg/L
Milligrams per liter
NC
North Carolina
NCAC
North Carolina Administrative Code
NCDEQ
North Carolina Department of Environmental Quality
ne
effective porosity
NTUs
Nephelometric Turbidity Units
ORP
Oxidation -Reduction Potential
Pace
Pace Analytical
PBTV
Provisional Background Threshold Value
Plant/Site
Mayo Steam Electric Plant
Shealy
Shealy Environmental Services
SOC
Special Order by Consent
SOP
Standard Operating Procedures
S.U.
Standard Units
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
LIST OF ACRONYMS (CONTINUED)
TDS
Total Dissolved Solids
µg/L
microgram per liter
USEPA
United States Environmental Protection Agency
UTL
Upper Tolerance Limit
Vs
seepage flow velocity
WWTB
Wastewater Treatment Basin
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
1.0 INTRODUCTION
1.1 Objectives and Purpose
The purpose of this report is to evaluate the data from the Interim Monitoring Plan
(IMP) groundwater monitoring performed at Mayo Steam Electric Plant (Mayo, Plant,
or Site) for the 2018 calendar year. IMP sampling is conducted at the Site to meet
requirements of the Coal Ash Management Act (CAMA) of 2014 (15A NCAC 13B .2001).
Sampling was conducted on monitoring wells designated as part of the IMP in
correspondence from the North Carolina Department of Environmental Quality
(NCDEQ), dated May 1, 2017 (Appendix A).
An Effectiveness Monitoring Program (EMP) is required by CAMA §130A-309.209
(b)(1)e. The EMP for Mayo is anticipated to begin once the basin closure and
groundwater CAP have been implemented. In the interim, an IMP has been developed
at the direction of NCDEQ. The CAP, and a proposed EMP, will be submitted at a
future date.
This report is prepared in accordance with NCDEQ's Division of Water Resources 2017
guidance document for the investigation of soil and groundwater contamination
(NCDEQ, 2017). Data were evaluated for groundwater quality, occurrence, and flow at
the Site. Constituents of interest (COIs) are those parameters with concentrations in
groundwater greater than one or more of the groundwater screening criteria; (North
Carolina Administrative Code [NCAC], Title 15A Subchapter 02L [02L], Interim
Maximum Allowable Concentration [IMAC], or approved background threshold value
[BTV]).
The distribution and concentration of COIs in groundwater within the surficial,
transition zone, and bedrock flow zones are discussed and evaluated with respect to
historical Site conditions. Changes to ash and wastewater handling systems at the Site
that occurred during 2018 that may affect groundwater conditions at the Site are also
documented and discussed.
Geometric means (geomeans) of the COI data is used to support the analysis of
groundwater conditions and to provide a basis for defining the extent of the COI
plume. The geomean method was selected in order to capture the central tendency of
the data, which may vary over several orders of magnitude. Reported geomeans were
calculated using the four quarters of IMP data from 2018. A single sample result may
not be an accurate representation of the concentrations observed over four quarters of
data in 2018. Evaluating plume geometries with geomean data limits the potential for
incorporating occasions when COIs are reported at concentrations outside of the typical
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
concentration range for a given sample location. Previous site assessments may have
over -represented areas impacted by the ash basin by posting a single data set on maps
and cross -sections that may have included isolated data anomalies. Rationale and
procedures for calculating geomeans are discussed in greater detail in Section 3.2.
1.2 Site Overview and History
Mayo is a coal-fired electricity -generating facility in north -central North Carolina
owned and operated by Duke Energy Progress, LLC (Duke Energy). The Site is situated
in the northeastern corner of Person County, north of the City of Roxboro. Figure 1-1
depicts the Site topography and nearby surface water features.
Mayo began coal-fired power production in 1983. There is a single ash basin located
northwest of the power block. The ash basin, which contains ash generated from the
Plant's historic coal combustion, is approximately 140 acres in size and is constructed
with an earthen dike. A 500-foot compliance boundary encircles the ash basin, except on
the northeastern edge of the Site where the compliance boundary is co -located with the
boundary of the Site.
Mayo coal combustion residuals (CCR) are now handled dry. Beginning in November
2014, CCR from Mayo has been placed in the on -site industrial landfill (Monofill)
(NCDEQ DWM Permit No. 7305-INDUS). Other CCR flows to the ash basin were
ceased in 2017 and processed through the Thermal Evaporator.
Groundwater flow is generally to the north from the ash basin.
1.3 Changing Site Conditions
Several changes to Site operations and conditions to support ash basin closure occurred
in 2018, or are scheduled to occur in 2019, that are relevant to ash basin groundwater
evaluation.
Decanting of the ash basin is anticipated to begin no later than June 30, 2019.
Transducers and geochemical sondes are in place in select wells in and around the ash
basin to record changes in water levels and geochemical parameters. Reducing the
hydraulic head in the ash basin through decanting will reduce the vertical and
horizontal hydraulic gradients that drive constituent migration, with the greatest
reduction near the dam. Further, in compliance with a Special Order by Consent
(August 2018), a seep collection system is operational that captures flow from the east
and west ash basin toe drains.
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
Construction of a lined retention basin (LRB), wastewater treatment basin (WWTB), and
associated conveyance piping was ongoing in 2018. This system will come online in
2019 to receive industrial stormwater currently flowing to the ash basin.
1.4 Regional Hydrogeology
The Site is located in the Piedmont Physiographic Province. A conceptual model of
groundwater flow in the Piedmont, which is applicable to Mayo, was developed by
LeGrand (1988, 1989) and Harned and Daniel (1992). The model describes a regolith and
bedrock drainage basin with a perennial stream valley system. Groundwater is
recharged by drainage in the highlands followed by discharge to the perennial stream.
Flow in the regolith follows porous media principles, while flow in bedrock is provided
by the presence of secondary porosity features (fractures). Rarely does groundwater
move beneath a perennial stream to another more distant stream or across drainage
divides (LeGrand, 1989).
1.5 Site Hydrogeology
Groundwater from the ash basin flows south to north toward Crutchfield Branch. The
topographically controlled flow direction provides natural hydraulic control of
potential COI migration within the former stream valley system. The predominant
direction of groundwater flow is to the north.
Three hydrostratigraphic units were identified at the Mayo Site.
• Surficial Zone (alluvium, residual soil, fill/reworked soil, and saprolite):
Thickness is related to the topography, type of parent rock and geologic history,
but is generally only a few feet at the Mayo. Saprolite beneath the Site is almost
entirely unsaturated. Saturated saprolite is more frequently encountered in the
extreme south area of the Site and around Crutchfield Branch in the northern
portion of the Site.
• Transition Zone: A relatively transmissive zone of partially weathered rock.
• Bedrock Zone: Fractured competent bedrock. As described in the 2017
Comprehensive Site Assessment (CSA) Update, most fractures observed at the
Site are small and do not seem to be well-connected based on available data and
observations (SynTerra, 2017).
Ash pore water is present as wastewater within the ash basin.
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
The following presents a generalized conceptual site model (CSM) for Mayo ash basin,
which was constructed within a former perennial stream valley in the Piedmont of
North Carolina:
• Generally, the physical setting for the ash basin within the former perennial
stream valley limits the horizontal and vertical migration of constituents to areas
near and directly downgradient of the basin dam.
• The stream downgradient from the dam is a groundwater discharge zone that
limits the horizontal migration of constituents downgradient of the basin.
• The groundwater flow paths (the area of potential constituent migration in
groundwater from the basins) remain in the former stream valley.
• Topographic ridges located in areas upgradient and side -gradient of the basin
reflect groundwater divides.
• Crutchfield Branch (downgradient from the dam) is a groundwater discharge
zone that limits the horizontal migration of constituents downgradient of the
basin.
• The migration of ash pore water to the underlying groundwater near the dam is
the primary mechanism for constituent transport.
• Boron is the CCR constituent most indicative of COI migration from the ash
basin with a discernable plume pattern. Other less mobile metals such as arsenic,
chromium, cobalt, and selenium, (if detected in groundwater), might be present
within the area of the boron plume but to a lesser extent.
• COI migration to downgradient surface water bodies has not caused constituent
concentrations to be greater than surface water quality standards under current
conditions.
In summary, the ash basin is a flow -through system with groundwater discharging into
the upgradient ends, flowing laterally through the central portions and migrating
downward in the vicinity of the ash basin dam, then flowing upward beyond the dam
toward Crutchfield Branch. This flow system, along with the stratified nature of the fly
ash and bottom ash in the basin, results in limited downward vertical migration of COIs
into the underlying groundwater upstream of the dam. In the vicinity of the dam,
groundwater flows downward out of the basin and under the dam. Beyond the dam,
groundwater flows upward toward the surface water discharge zone, limiting
downward migration of COIs to the area near the dam. Boron is the CCR constituent
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
most indicative of groundwater migration from the ash basin with a discernable plume
pattern.
Monitoring wells are installed in the surficial, transition, and bedrock flow zones as part
of the on -going ash basin assessment activities. Figure 1-2 illustrates the locations of the
CAMA monitoring well network with respect to the ash basin and Site infrastructure.
Table 1-1 is a well construction table of CAMA monitoring wells included in the 2018
IMP plus additional wells installed in 2018.
1.6 Previous Reporting
Detailed descriptions of the Site operational history, the CSM, physical setting and
features, geology/hydrogeology, and results of the findings of CAMA-related work are
documented in full in the following reports:
• Comprehensive Site Assessment Report - Mayo Steam Electric Plant (SynTerra, 2015a).
• Corrective Action Plan Part 1 - Mayo Steam Electric Plant (SynTerra, 2015b).
• Corrective Action Plan Part 2 — Mayo Steam Electric Plant (SynTerra, 2016a).
• Comprehensive Site Assessment Supplement 1— Mayo Steam Electric Plant
(SynTerra,2016b)
• Comprehensive Site Assessment Update — Mayo Steam Electric Plant (SynTerra, 2017)
NCDEQ provided partial approval of background threshold values in a letter to Duke
Energy dated May 14, 2018 (Appendix A). Comparisons of data to BTVs in this report is
in reference to those approved values. BTVs will be further refined and updated in
2019.
In a letter dated May 7, 2018, NCDEQ indicated that assessment activities are sufficient
to proceed with preparing a corrective action plan (CAP), However, additional
assessment activities were identified to (e.g., groundwater to surface water migration)
be addressed in conjunction with preparation of a CAP.
This report provides an evaluation of the groundwater data collected during the 2018
calendar year. The following sections will present the 2018 CAMA monitoring data and
provide an integrated interpretation of site conditions and plume status.
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
1.7 Overview of Findings for 2018
Key findings of the CAMA groundwater data for 2018 include:
• No imminent hazards to public health and safety have been identified.
• The ash basin is considered the primary source of CCR-related constituent
concentrations in groundwater at the Site.
• COIs are contained within Duke Energy's property with the exception of
unoccupied private property located north of Mayo Lake Road and
downgradient of the ash basin.
• The ash basin is a flow -through basin with groundwater migration into the
upgradient ends. Groundwater flows predominantly laterally through the
middle regions with downward migration in the vicinity of the dam. COI
transport is downward out of the basin and under the dam. Downgradient of the
dam, the hydraulic gradient causes upward flow toward the surface water
discharge zone, limiting downward vertical migration of COIs.
• Bedrock groundwater exhibits CCR-related effects at areas with a strong
downward vertical gradient, as seen at the ash basin dam.
• Boron continues to be a key indicator of plume characteristics associated with the
ash basin. Additional COIs identified as being greater than their respective
standards are generally confined within the extent of the boron plume at the Site.
• Cobalt, molybdenum, manganese, total dissolved solids (TDS), and strontium
have been detected at concentrations greater than applicable comparison criteria
at areas downgradient of the ash basin based on geomeans of 2018 data.
• Based on review and comparison with historical Site data, the COI plume at the
Mayo Plant appears to be stable.
• Boron concentrations in the surficial and transition flow zones downgradient of
the basin have decreased. Mayo received a SOC in August 2018, which requires
continuous operation of a collection system for water at the toe of the dam.
Fourth quarter 2018 groundwater sampling occurred after the collection system
began regular operations; whereas, third quarter 2018 sampling occurred prior to
regular collection system operations.
• Analytical results for the third and fourth quarter 2018 sampling events indicate
a reduction of boron concentration in wells CW-2D and MW-16S, located
downstream of the ash basin dam.
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
• Based on updated 2018 flow and transport modeling (SynTerra, 2018), decanting
of the ash basin is predicted to cause the boron plume to recede. Evaluation of
2019 sampling results will provide additional data to determine if the previously
estimated boron plume has receded inside the compliance boundary as fourth
quarter 2018 results indicate.
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
2.0 2018 MONITORING ACTIVITIES
2.1 2018 Quarterly Sampling Schedule
The CAMA IMP monitoring well network was sampled on a quarterly basis during
2018. New wells installed during the year were included in the monitoring network.
New wells will be monitoring quarterly until four events have occurred. Thereafter the
data will further evaluated to determine the appropriate monitoring frequency. The
sampling events occurred in accordance with the IMP schedule on the following dates:
• Quarter 1 January 15 through 22, 2018
• Quarter 2 April 2 through 4, 2018
• Quarter 3 July 17 through19, 2018
• Quarter 4 November 6 through 8, 2018
Groundwater sampling was performed by technical personnel from Duke Energy or
subcontracted by Duke Energy. Comprehensive data submittal to NCDEQ occurred on
a monthly basis in 2018 until a quarterly submittal schedule was approved by NCDEQ
(June 6, 2018 email to Duke Energy), in accordance with the following schedule:
• Monthly: January through June 2018
• Quarterly: Quarter 3 September 2018
Quarter 4 January 2019
2.2 Changes to the CAMA Groundwater Monitoring Network
One CAMA monitoring well was abandoned at the Site in 2018. Eleven CAMA wells
were installed at the Site in 2018 to address data gaps identified in the 2017 CSA Update
(SynTerra, 2017). Monitoring wells BG-01, BG-02, CW-01/D, CW-02/D, CW-03/D, CW-
04, CW-05, CW-06, MW-02, MW-03, and MW-12S/D are dual-purpose wells
incorporated in both the IMP and CCR groundwater monitoring networks.
Wells Abandoned during 2018
• ABMW-04 Abandoned due to erosion that undercut well pad
Wells Installed during 2018
• ABMW-04X Replacement well for ABMW-04
• MW-103BRM Deep bedrock well downgradient of the ash basin
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
• MW-103BRL
Deep bedrock well downgradient of the ash basin
• MW-104BRM
Deep bedrock well downgradient of the ash basin
• MW-104BRL
Deep bedrock well downgradient of the ash basin
• MW-105BRM
Deep bedrock well downgradient of the ash basin
• MW-105BRL
Deep bedrock well downgradient of the ash basin
• MW-107BRM
Deep bedrock well downgradient of the ash basin
• MW-107BRL
Deep bedrock well downgradient of the ash basin
• AP-6
Ash basin pumping test well
• CCR-109BR
CCR characterization well
Well installation and abandonment documentation for 2018 are included in Appendix
B. Well locations are shown on Figure 1-2.
2.3 Water Level Measurements
During each 2018 quarterly IMP sampling event, water levels were measured for the
CAMA monitoring well network. Water level maps of monitored flow zones were
prepared based on the December 2018 sampling event as discussed in Section 3.1. This
information was used to calculate groundwater flow direction and rate. Water levels
were recorded during a 24- to 48-hour period (prior to well purging and sampling)
using an electric water level indicator and referenced to a surveyed top of casing mark.
USEPA CCR Rule compliance monitoring well water level data are generally not
included in data evaluations for 2018 because water levels from the wells were not
collected during the 24-hour period in which CAMA IMP water levels were collected.
As of Q12019, Duke Energy has implemented an optimized program that includes
selected CCR wells to provide better water level data coverage across the Site.
Groundwater elevations calculated from water levels measured during each quarterly
2018 IMP sampling events are provided in Table 2-1. Groundwater flow direction and
velocity is discussed in Section 3.1. A copy of the water level measurements from the
CAMA monitoring well network is included in Appendix B.
2.4 Groundwater Sampling Methods
Field personnel conducted groundwater sampling following procedures outlined in the
NCDEQ approved Low Flow Sampling Plan, Duke Energy Facilities, Ash Basin Groundwater
Assessment Program, North Carolina, June 10, 2015. Groundwater sampling using low
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flow methods helps to reduce agitation during sampling, resulting in lower sample
turbidity. A copy of the Low Flow Sampling Plan is included as Appendix C.
Field personnel measured and recorded groundwater quality field parameters during
the monitoring well purging process. The field parameters included the following: pH,
specific conductivity, temperature, dissolved oxygen (DO), oxygen -reduction potential
(ORP), and turbidity.
Upon collection of a groundwater sample, the chain of custody (COC) was updated and
kept with the respective samples. Upon completion of the sampling, the sample bottles
were packed on ice and chilled to approximately 4 degrees Celsius (°C). The sample
coolers and accompanying COCs were shipped to Duke by courier. Copies of sampling
logs are included in Appendix B.
2.5 Laboratory Analyses
The groundwater samples were analyzed for the parameters listed in the IMPS at the
time of collection (Appendix A). NC Certified Laboratories performed groundwater
quality analyses for selected constituents. GEL Laboratories performed the radiological
analyses on the groundwater samples.
2.6 Quality Control Summary (Data Validation)
Data review and validation is conducted for CAMA analytical sampling. Data review is
a systematic process for evaluation of data against a predefined set of criteria to provide
assurance that the data meet project analytical Data Quality Objective (DQO)
requirements. The purpose of the data review process is to evaluate whether the
usability of analytical data is affected by the overall analytical processes and sample
collection and handling procedures. If specific analytical DQOs are not met, the data are
qualified (i.e., data flags are assigned to sample results) in accordance with guidelines
established by the United States Environmental Protection Agency (USEPA, November
2002). Data review allows the data user to adequately determine whether the data can
be used for its intended purpose. The data acceptance criteria are established according
to Standard Operating Procedures (SOPs) and Statements of Work provided to the
contracted analytical laboratory.
Upon receipt of the groundwater analytical data from the respective laboratories, the
data is uploaded into the project -specific database. SynTerra performs independent
quality control checks of field and laboratory procedures that are used in collecting and
analyzing the data. Steps and guidelines followed during the data validation process
are modeled on the USEPA Contract Laboratory Program National Functional
Guidelines for Organic Superfund Methods Data Review (USEPA, January 2017a),
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USEPA Contract Laboratory Program National Functional Guidelines for Inorganic
Superfund Methods Data Review (USEPA, January 2017b), Multi -Agency Radiological
Laboratory Analytical Protocols Manual (MARLAP), Manual Volume I: Chapter 8,
Radiochemical Data Verification and Validation (MARLAP, July 2004), and Data
Validation Standard Operating Procedures for Contract Laboratory Program Routine
Analytical Services Inorganic Analysis (USEPA, September 2011). In addition, method -
specific criteria set forth in the compendium of analytical methods found in the Test
Methods for Evaluation Solid Waste; Physical/Chemical Methods (SW-846), Update VI
(USEPA, November 2017 [Phase I] and July 2018 [Phase II]) are also evaluated during
the validation process. The data review process has been adapted to meet the analytical
DQO requirements for generation of definitive critical data.
Quality control checks verify that the data collected are of appropriate quality for the
intended data use and that the analytical DQOs are met. Thus, all data determined to be
useable should be considered compliant and adequate for its intended use of
monitoring water quality at the Site.
Data validation checklists that were completed for each laboratory package, by quarter,
are presented in Appendix D.
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3.0 2018 MONITORING RESULTS
3.1 Site -Wide Groundwater Occurrence and Flow
No significant changes in water levels or groundwater flow directions are noted in the
fourth quarter 2018 groundwater elevation data compared to previous measurements
dating back to 2015. The findings are consistent with prior assessment and monitoring
data for the Mayo Site.
Monitoring well locations are shown on Figure 1-2. Water level elevations for the
CAMA IMP monitoring in 2018 are summarized in Table 2-1. In large portions of the
subsurface at the Mayo Plant, the surficial flow zone and transition zone are not
saturated and shallow bedrock is where groundwater is first encountered.
Water level maps were constructed from the most recent water level elevations
measured for the fourth quarter (November 2018) (Figure 3-1 through Figure 3-3).
General groundwater flow directions can be inferred from the water level contours on
water level maps. Groundwater beneath the Site generally flows north-northeast, across
the basin and toward Crutchfield Branch stream valley, in all flow zones. There is very
little difference between water levels in the surficial or transition zones, where
saturated, as compared to the bedrock, except immediately downgradient of the ash
basin dam.
Hydrographs of select wells are presented in Figure 3-4. Water levels in areas
upgradient (MW-12S/D), within the basin (ABMW-2/BR/BRL), immediately
downgradient of the dam (CW-2/1)), and downgradient of the Site (MW-16S/D/BR) are
consistent over time.
Figures 3-5 through 3-7 show plan view velocity vector maps for groundwater in the
each of the three primary flow zones described for Mayo (saprolite, transition zone, and
bedrock). Figure 3-8 is a cross-section velocity vector map oriented approximately
southwest to northeast through the center of the ash basin. This figure was created from
comprehensive Site data incorporated into the Site's flow and transport model. Black
arrows illustrate the direction and magnitude of groundwater flow at thousands of
individual modeled locations. Various colors illustrate relative flow velocities in feet per
day (ft/day). These figures provide additional support in understanding groundwater
flow throughout Mayo in three dimensions. Key conclusions from evaluation of these
figures include:
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• Velocity vector maps (Figures 3-5 through 3-7) generally align with groundwater
flow directions throughout the Site inferred from water level maps (Figures 3-1
through 3-3).
• Horizontal groundwater flow velocities in areas with free ponded water within
the ash basin (Figure 3-5) are less than those seen upgradient of the ash basin
and below the ash basin dam (Figure 3-6 and 3-7).
• Downgradient of the ash basin dam, groundwater in all flow zones flows toward
Crutchfield Branch, which is the main groundwater discharge point (Figures 3-6
through 3-8).
• Higher groundwater velocities are indicated in each flow zone immediately
downgradient of the ash basin dam (Figures 3-6 through 3-8).
• Groundwater flow velocities and directions, as indicated by the flow velocity
vector maps, confirm the conceptual model of groundwater flow at the Mayo
Site.
3.1.1 Ash Basin Groundwater Occurrence and Flow
In 2018, wells were installed downgradient of the ash basin to characterize
groundwater in deep bedrock near the dam. Figure 3-9 shows cross section A -A'
oriented northwest to southeast across the ash basin, perpendicular to the
general direction of groundwater flow. Figure 3-10 shows cross section B-B'
oriented southwest to northeast through the ash basin in the direction of
groundwater flow. The groundwater levels and flow directions based upon
November 2018 data are illustrated on the figures. The calculated geomeans for
boron concentrations in 2018 are posted at the respective well locations at the
screened intervals to provide a representation of boron distribution with depth.
Detailed observations concerning groundwater flow in the vicinity of the ash
basin include:
• Groundwater flow direction in this area is northeast to Crutchfield Branch
(Figures 3-1 through 3-3).
• Ash pore water exhibits predominantly horizontal flow in the upgradient
portion of the ash basin with slight downward flow into the thin saprolite
zone and transition zone beneath the basin.
Upstream of the ash basin dam where there is free ponded water, there is
a strong downward vertical gradient as depicted in the groundwater flow
and transport model (Figure 3-8).
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• Downstream of the dam, there is a strong upward vertical gradient that
produces some artesian conditions in low lying areas (Figure 3-8).
3.1.2 Horizontal Gradients
Groundwater elevations from the fourth quarter 2018 were used in this
evaluation (Table 3-2). Horizontal hydraulic gradients were derived for the
transition and bedrock flow zones using November 2018 water level
measurements. Those gradients were derived by calculating the difference in
hydraulic head over the length of an inferred flow path between two water level
contour intervals within the same flow zone (Table 3-1). The following equation
was used to calculate horizontal hydraulic gradients:
i=dh/dl
Where i is the hydraulic gradient; dh is the difference between two hydraulic
heads (measured in feet); and dl is the flow path length between the two water
level contours within the same flow zone (measured in feet).
Applying this equation along generalized groundwater flow paths observed at
the Site, shown in Figures 3-1 through 3-3 cross the ash basin dam, the hydraulic
gradient in the saprolite is approximately 0.25 feet per foot (ft/ft), the hydraulic
gradient in the transition zone is approximately 0.17 ft/ft, and the hydraulic
gradient in the bedrock is approximately 0.16 ft/ft (Table 3-1).
3.1.3 Vertical Gradients
The vertical hydraulic gradient (dhldl) is calculated at clustered wells from the
water level data and the midpoint elevations of the well screens. Overall, the
vertical gradient magnitude and directions observed at the Site are similar in
magnitude and direction to the vertical gradients presented in the CSA reports
(SynTerra, 2018).
Site -wide
The vertical gradients illustrated on well hydrographs (Figure 3-4) and
determined from flow and transport modeling (Figure 3-4) support the
assumptions of the CSM. Groundwater flows laterally through the basins with
downward migration in the vicinity of the peripheral dikes and basin dams.
Upward vertical gradients occur below the dams and dikes in the vicinity of
receiving water bodies (groundwater discharge areas).
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Ash Basin
Pore water flow within stratified ash and the groundwater flow beneath the ash
basin in the saprolite is generally horizontal with a small downward component.
Upward vertical gradients in the bedrock beneath the ask basin limit the
downward transport of COIs. Groundwater in the transition zone and bedrock
flow zones in the vicinity of the ash basin dam travels underneath the dam
upward toward Crutchfield Branch.
Figure 3-8 illustrates groundwater velocity vectors and magnitudes on a cross-
section oriented through the ash basin. An upward vertical gradient under the
basin near former stream valleys has been observed. This upward gradient acts
to limit downward vertical migration of COIs under the basin. Upstream of the
dam, the gradient from ash pore water to groundwater is downward. Within the
ash basin, a small upward vertical gradient occurs in the vicinity of ABMW-
04/D/BR cluster between ash pore water and both the transition zone and
bedrock flow zones. Downward gradients were observed in the ABMW-
02/BR/BRL and ABMW-03/S clusters (Table 3-2). These findings support the
CSM. A downward vertical gradient is expected to be present in the saprolite,
transition, and bedrock zones just upstream of the ash basin dam. There are no
monitoring wells in the area immediately upgradient of the dam due to the
presence of ponded water. In topographic low areas directly downslope from the
ash basin dam, artesian conditions are present (MW-104BRM, MW-104BRL, MW-
105BRM, CCR-104BR). There is a slight downward gradient farther
downgradient from the dam at MW-16S/BR and CW-02/1) (Table 3-2).
Crutchfield Branch is a losing stream in the area of the MW-16 well cluster,
which is supported by the observed downward gradient, due to impounded
water conditions in the stream. These findings are consistent with the CSM.
3.1.4 Groundwater Seepage Velocity
Groundwater seepage velocities are calculated using horizontal hydraulic
gradients (Table 3-1) determined from measurements collected in the fourth
quarter of 2018. Hydraulic conductivity and effective porosity values are taken
from the November 2018 updated flow and transport model (Murdoch et al.,
2019). Calibrated conductivity and porosity values for each flow zone were used
to align velocity calculations with model predictions.
Hydraulic conductivities presented in the November 2018 Updated Flow and
Transport Model are:
Hydraulic conductivity (k):
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• Surficial: 3.0 feet per day (ft/day),
• Transition Zone: 1.0 ft/day,
• Bedrock: 0.03 ft/day.
Effective porosity (n,):
• Surficial: 20 percent,
• Transition Zone: 20 percent,
• Bedrock: 5 percent.
The horizontal groundwater seepage flow velocity (vs) is estimated using a
modified form of the Darcy Equation (Table 3-1).
k dh
_
VS ne (dl)
The November 2018 quarterly sampling event, horizontal groundwater flow
velocity in the vicinity of the ash basin dam is calculated to be:
• Surficial: 3.72 ft/day (1,357.36 ft/yr)
• Transition Zone 0.86 ft/day (312.41 ft/yr)
• Bedrock: 0.09 ft/day (34.29 ft/yr)
These groundwater velocities are averages for flow across the Site and are within
the magnitude ranges for the velocities illustrated on Figures 3-4 through 3-6.
3.2 Data Reduction and Evaluation
No outliers were identified in the evaluation of the 2018 CAMA IMP groundwater
sampling data. All data on Table 3-5 have been included for use in evaluating plume
geometry in the vicinity of the ash basin.
Groundwater samples from the CAMA monitoring well network were analyzed for the
applicable constituents listed on the IMP approval letters (Appendix A). The analytical
results from each sampling event in 2018 are summarized on Table 3-3. Data qualifiers
and acronyms specific to the data table are summarized and defined on Table 3-4.
Laboratory analytical reports and accompanying data validation checklists are
presented in Appendix D.
The geomean of sampling results for 2018 CAMA data is calculated for each identified
COI to support the analysis of groundwater conditions and provide a basis for defining
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the extent of the plume in 2018. The geomean method was selected in order to capture
the central tendency of the data, which might vary over several orders of magnitude. If
four quarters of valid data were not available, the most recent valid sample result was
reported. Four quarters of valid data were not available either because the well was
recently installed or sample results from one quarter were excluded. For use in
calculating geomeans, non -detect values were assigned the lab detection limit, and
estimated (J-flag) values were treated as the value reported.
Based on USEPA's National Functional Guidelines (USEPA, 2017a, 2017b), published
research on the leaching behavior of elements from coal combustion fly ash (Izquierdo
and Querol, 2012), and professional judgement, sample results were excluded from
calculations for the following conditions:
• turbidity was greater than 10 Nephelometric Turbidity Units (NTUs)
• pH was greater than 10 standard units (S.U.) (for antimony, arsenic,
molybdenum, selenium, and vanadium only)
• if the data was flagged as unusable (RO qualified)
• if the data was non -detect at a reporting limit greater than the normal laboratory
reporting limit
Table 3-5 presents the calculated geomeans of the quarterly COI data. The grey
highlighting in the table illustrates which reported values are not calculated geomeans.
When geomeans could not be calculated, the most recent valid sample was evaluated to
determine whether the sample result is an appropriate representation of the historical
dataset. Sample results with COI concentrations significantly greater or lesser than the
historical average concentration were identified as outliers.
Geomeans are used to evaluate the occurrence of COIs at the Site. A single sample
result may not be an accurate representation of the concentrations observed over four
quarters of data in 2018. Evaluating plume geometries with geomeans limits the
occurrence of isolated COIs at concentrations greater than enforceable groundwater
standards. Previous site assessments have identified these isolated areas as not
impacted by the ash basins and provided evidence based on groundwater flow
direction and other constituent migration patterns (SynTerra, 2017).
Data from CCR Rule compliance monitoring wells are used for evaluating plume
geometry. Data from CCR wells is used in this report on isoconcentration figures and
time -series plots for a complete evaluation of COI occurrence in the vicinity of the ash
basins. These figures are discussed in Sections 3.4, 3.5, and 3.6 of this report.
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The BTVs, 02L standard, and or IMAC for each COI are summarized by flow layer at
the top of Table 3-3. Text, figures, and tables in this report reflect the updated BTVs
approved by NCDEQ in 2017. Per 15A NCAC 02L .0202(b)(3), site -specific BTVs
calculated at concentrations greater than 02L standards or IMACs are the enforceable
groundwater standards. The BTVs for the Site are anticipated to be updated and
included in the 2019 CAP Update.
Table 3-6 is a summary of an evaluation of COIs at the Site. The COI list from the 2018
CSA Update was evaluated to determine which COIs effectively define the plume in the
vicinity of the ash basin. Table 3-6 provides the following information:
• Applicable comparison criteria (02L standard, IMAC, or approved BTVs).
• Maximum 2018 geomean concentration near or outside compliance boundary.
• Exceedance ratio of the maximum geomean divided by the comparison criteria
value.
• The number of wells above criterion near or outside of the compliance boundary.
• Rationale for not including specific COIs in isoconcentration figures or time -
series plots.
Constituents that are detected near or beyond the compliance boundary at exceedance
ratios greater than one are appropriate for defining plume geometry. For the purposes
of monitoring groundwater quality, boron provides a good indication of the occurrence
and distribution of CCR-related COIs.
Manganese concentrations greater than the statistically derived background values
occur but do not correlate precisely with the boron distribution pattern. Therefore,
mapping the manganese concentrations in groundwater is not considered as useful for
the purpose of depicting COI migration from the ash basin as mapping the boron
distribution.
Arsenic, barium, total chromium, hexavalent chromium, iron, sulfate, and vanadium
were included as COIs in the CSA Update (SynTerra, 2017). These constituents do not
occur near or outside of the compliance boundary at concentrations greater than
criterion (Table 3-6).
COIs are those parameters with concentrations greater than groundwater screening
criteria (NCDEQ 02L standard, Interim Maximum Allowable Concentration [IMAC], or
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background threshold values). COIs that meet the following criteria may be designated
for future corrective action:
1) Occur downgradient of the ash basin in the direction of groundwater flow;
2) Exhibit concentrations in groundwater at or beyond the compliance boundary
greater than the 02L standard, IMAC, or approved background values,
whichever is greater;
3) Exhibit high to variable mobility (exhibit a discernable plume); and
4) Demonstrate correlation with other soluble constituents associated with coal ash.
Based on the criteria above, the following groundwater COIs are anticipated to be
evaluated in the CAP Update:
Boron Cobalt Manganese
Molybdenum Strontium Total Dissolved Solids
(TDS)
The groundwater COIs identified at Mayo occur in CCR and are also naturally
occurring in groundwater. Certain COIs (e.g., cobalt and manganese) have background
concentrations in some flow zones at the Site greater than their 02L standard or IMAC.
The 2017 CSA Update used Provisional BTVs (PBTVs) for comparison. NCDEQ
approved all BTVs for Mayo in a letter to Duke Energy dated May 14, 2018. The BTVs
for the Site will be updated and submitted to NCDEQ to be approved for inclusion in
the 2019 CAP.
Table 3-7 provides a summary of background threshold values calculated for the Site
COIs as defined in the 2017 CSA Update. The table includes previously approved BTVs
BTVs are statistically derived upper tolerance limits (UTLs). The UTL represents an
upper limit of a range of values in which a specified proportion of the data population
resides with some level of statistical confidence. Concentrations observed in upgradient
wells at the Site may exceed BTVs but still be within the range of typical background
concentration in the North Carolina Piedmont. Table 3-7 includes constituent
concentration ranges detected in background wells at Mayo and regional concentration
ranges detected in background wells in the six Duke Energy facilities located in the
North Carolina Piedmont.
Isoconcentration maps and time series plots for selected constituents are the basis of
evaluation of plume geometry and concentration trends for the source area in Sections
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3.4, 3.5, and 3.6. As a result, boron is the COI selected for creating isoconcentration
maps because:
• Boron is detected at concentrations greater than 02L standards, IMACs, or BTVs
downgradient of the ash basin.
• Boron is relatively mobile in groundwater as compared with other COIs. Boron
can, therefore, provide an indication of the areal extent of CCR-related COIs in
groundwater at the Site.
• Plume migration is typically evaluated by means of a conservative (non -reactive)
constituent with low or well- established concentrations in the natural
environment. Cobalt and manganese are both geochemically reactive
constituents with a potential for sub -surface transport (i.e., mobility determined
by laboratory and PHREEQC simulated sorption coefficients) which varies
orders of magnitude over the range of redox and pH conditions observed at the
Site. Additionally, a study conducted by Polizzotto, et al. (2015) found that
roughly 50 % of wells in NC have manganese concentrations greater than the 02L
Standard (50 µg/L). This same report noted that manganese in NC is naturally
sourced. Cobalt is known to naturally associate with manganese minerals in the
Southeastern United States (Pierce, 1944). Given the geochemically reactive
nature of cobalt and manganese and their known prevalence in the Piedmont
Region of NC, they are not suitable constituents for evaluation of plume
geometry.
Time -series graphs for wells located within and at the leading edge of the ash basin
plume were produced to provide an ongoing evaluation of change in water quality
through time for key monitoring wells. COIs selected for time -series evaluations
include the following:
• Boron
• Cobalt
• Strontium
Isoconcentration maps depicting the distributions of boron in the saprolite, transition
zone, and bedrock flow zones across the Site are provided as Figures 3-11 through 3-13
and discussed in Sections 3.4.1, 3.5.1, and 3.6.1. Time -series plots presenting historic
concentrations of boron, cobalt, and strontium at select monitoring wells within and
downgradient of the ash basin are provided as Figures 3-14 through 3-15 and discussed
in Sections 3.4.1 and 3.5.1.
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3.3 Ash Basin Water Quality
3.3.1 Site Conditions
Decanting of the ash basin is anticipated to begin in Quarter 2 of 2019.
Transducers are in place in wells near the ash basin to record changes in water
levels and geochemical parameters, including pH and ORP.
3.3.2 Constituent Occurrence and Plume Status
The geomean of the 2018 IMP monitoring boron and cobalt data were used to
evaluate COIs in groundwater (Table 3-5). Boron is used to delineate the
groundwater plume related to the ash basin because it is considered an indicator
constituent for groundwater influence from CCR. Cobalt, manganese,
molybdenum, and strontium occurrence outside the extent of boron is discussed
below.
Boron
Figures 3-11, 3-12, and 3-13 are isoconcentration maps illustrating the occurrence
of boron in the saprolite, transition zone, and bedrock across the Site based on
geomeans of 2018 IMP data. Observations about boron distribution include:
• Boron is detected at concentrations greater than 02L in one saprolite well
(ABMW-03S) and one transition zone well (ABMW-04D) installed beneath
the ash basin. (Figure 3-12).
• Boron is detected at concentrations greater than 02L in three bedrock wells
immediately downgradient of the ash basin dam (CCR-107BR, CCR-
105BR, CCR-103BR) (Figure 3-13).
• Boron is detected at concentrations greater than 02L in two transition zone
wells immediately downgradient of the dam (CCR-105D and CCR-103D)
within the compliance boundary of the ash basin. (Figure 3-12).
• Boron is not detected above 02L beyond the compliance boundary in the
transition zone.
• Boron is not detected outside the compliance boundary in bedrock.
• Migration of ash pore water is limited in depth beneath the ash basin.
Boron is not detected at concentrations greater than 02L in the bedrock
flow zone wells beneath the ash basin (Figure 3-13)
Well CW-02 (transition zone) is located downgradient of the ash basin dam near
the current compliance boundary. Historical boron concentrations have been
above the 021,; however, in the last quarter of 2018, the boron concentration in
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CW-02 has decreased below the 02L. The well will be closely evaluated during
2019 monitoring. Observations of boron concentrations in groundwater, as
presented above, provide evidence supporting predominantly horizontal flow
through the basin in the CSM. Downward migration of ash pore water is limited
beneath the basin. As discussed in Section 3.1, downward migration of
groundwater is observed at the ash basin dam. There is no ash pore water data
near the dam because of standing water in the vicinity.
Cobalt
As shown on Table 3-5, cobalt is detected at concentrations greater than
background in bedrock groundwater downgradient of the ash basin. Figures 3-
14 and 3-15 are time versus concentration graphs of boron, cobalt, and strontium
at wells located within the boron plume. The following observations are made
when considering the distribution of cobalt:
The statistically derived Site background value for cobalt in bedrock
groundwater is 1.19 µg/L. The IMAC is 1 µg/L. The Site background value
for cobalt is used as the primary comparison value (Table 3-7). In 2018,
cobalt concentrations greater than the statistically derived background
value are contiguous with boron concentrations greater than 02L in
bedrock groundwater downgradient of the ash basin dam (Table 3-5).
Concentrations of cobalt observed in background wells in all flow units
range from 1 to 6.53 µg/L in all units (Table 3-7). All cobalt concentrations
in 2018 were within the range of background concentrations observed
(Table 3-7).
• Cobalt concentrations are stable at all locations along the centerline of the
plume (Figures 3-14 and 3-15).
Cobalt is not observed at concentrations greater than IMAC in the transition zone
or surficial zone (Table 3-5). There are inconsistent detections of cobalt greater
than background in transition zone and bedrock groundwater, which fall within
the range of concentrations observed in background wells.
Manganese
As shown on Table 3-5, manganese is detected at concentrations greater than
background in saprolite beneath the ash basin (ABMW-03S), in the transition
zone beneath the ash basin (ABMW-04D), in groundwater downgradient of the
ash basin in the bedrock (MW-02, MW-03BR), in the saprolite (MW-03), side -
gradient of the ash basin in the transition zone (MW-19D), and side -gradient of
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the ash basin in the bedrock (MW-05BR, MW-18BR, MW-19BR,). The following
observations are made when considering the distribution of manganese:
Manganese is detected at concentrations greater than background in the
transition zone beneath the ash basin (ABMW-04D), in groundwater
downgradient of the ash basin in the bedrock (MW-02, MW-03BR), in the
saprolite (MW-03), side -gradient of the ash basin in the transition zone
(MW-19D), and side -gradient of the ash basin in the bedrock (MW-05BR,
MW-18BR, MW-19BR).
The approved, statistically derived background value for manganese in
the surficial zone is 253 µg/L, in the transition zone is 298 µg/L, and in
bedrock groundwater is 544 µg/L. The 02L is 50 µg/L. The Site
background values for manganese were used as the primary comparison
value (Table 3-7).
• Concentrations of manganese observed in background wells in all flow
units range from 5 µg/L to 648 µg/L (Table 3-7).
• Manganese concentrations at the Site have not been conclusively proven
to originate from the ash basin. Manganese exceeds the approved
background threshold value outside of the compliance boundary and
downgradient of the ash basin at MW-16BR and CW-06 (Table 3-5). The
geomean of concentrations at CW-06 (1371 µg/L) is consistent with
concentrations at wells side -gradient of the ash basin where boron is not
detected (e.g. MW-05BR, MW-18BR, MW-19BR).
The background concentrations of manganese at Mayo exceed the 02L standard
by an order of magnitude. Occurrences of manganese in groundwater at any
location on the Site are at least in part due to these naturally high concentrations
given the range of concentrations observed in background (Table 3-7) and side -
gradient (Table 3-5) wells. There have not been distinct trends in manganese
historically (SynTerra, 2017) and concentrations have been sporadic and
inconsistently detected.
Molybdenum
Geomeans of concentrations of molybdenum are presented in Table 3-5.The
following observations are made when considering the distribution of
molybdenum:
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• Molybdenum is detected at concentrations greater than background in the
transition zone beneath the ash basin (ABMW-04D), in the transition zone
downgradient of the ash basin (MW-16D), in the bedrock downgradient of
the ash basin (MW-16BR), and in the bedrock side -gradient to the ash
basin (CW-01D).
The approved, statistically derived background value for molybdenum in
saprolite groundwater is 3.15 µg/L, in transition zone groundwater is 1
µg/L and in bedrock groundwater is 13.1 µg/L. There are no regulatory
standards for molybdenum in groundwater. The Site background values
for molybdenum are used as the comparison value (Table 3-7).
Concentrations of molybdenum observed in background wells in all flow
units range from 0.5 µg/L to 12.9 µg/L (Table 3-7). In 2018, molybdenum
concentrations greater than background occur downgradient of the
leading edge of boron concentrations above 02L in MW-16D (5.3 µg/L)
and MW-16BR (23.5 µg/L) (Table 3-5). The molybdenum concentration at
MW-16D is within the range of concentrations observed in background
wells at the Site.
• Molybdenum is also detected at concentrations greater than background
in CW-01D, southeast of the ash basin, where boron was not detected
(Table 3-5).
• Concentrations of molybdenum greater than the Mayo BTVs
downgradient of the ash basin are consistent with, and often less than,
values of molybdenum in background wells at other Duke Energy ash
basins in the Piedmont (Table 3-7).
Molybdenum concentrations at the Site have not been conclusively proven
to originate from the ash basin. Molybdenum exceeds the approved
background threshold value outside of the compliance boundary and
downgradient of the ash basin at MW-16D and MW-16BR (Table 3-5).
The geomeans of concentrations at MW-16D (5.3 µg/L) and at MW-16BR
(23.5 µg/L) are consistent with concentrations at wells side -gradient of the
ash basin where boron is not detected (e.g. MW-09BRL, MW-18BR, CW-
01D).
Strontium
Geomeans of concentrations of strontium are presented in Table 3-5. Figures 3-
14 and 3-15 are time versus concentration graphs of boron, cobalt, and strontium
Page 3-13

2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
at wells located within the boron plume. The following observations are made
when considering the distribution of strontium:
Strontium is detected at concentrations greater than background in the
saprolite beneath the ash basin (ABMW-03S), in the saprolite
downgradient of the ash basin (MW-16S, MW-03), in the bedrock beneath
the ash basin (ABMW-02BR, ABMW-02BRL, ABMW-04BR), and in the
bedrock side -gradient to the ash basin (MW-18BR, MW-19BR).
The statistically derived Site background value for strontium in saprolite
groundwater is 25 µg/L, in transition zone groundwater is 391 µg/L and in
bedrock groundwater is 418 µg/L. There are no regulatory standards for
strontium in groundwater. The Site background values for strontium are
used as the comparison value (Table 3-7).
• Concentrations of strontium observed in background wells in all flow
units range from 12 µg/L to 430 µg/L (Table 3-7).
Strontium is also detected at concentrations greater than background in
MW-18BR and MW-19BR, southeast of the ash basin, where boron was not
detected (Table 3-5). MW-18BR and MW-19BR are located on the opposite
side of a groundwater divide from the ash basin.
• Strontium concentrations are stable in the wells along the plume
centerline (Figures 3-14 and 3-15).
Mixing of groundwater from the various flow layers beneath and downgradient
of the ash basin may be causing concentrations above the BTV in the saprolite
downgradient of the dam. Concentrations of strontium greater than the BTV
downgradient of the ash basin are consistent with background values of other
flow layers (Table 3-5). The CSM shows that there is mixing between flow layers
as ash pore water flows downward upgradient of the dam through the bedrock
and then upward immediately downgradient of the dam (Figure 3-8).
Concentrations of strontium observed side -gradient to the ash basin in bedrock
are only slightly above background and not attributable to the ash basin due to
the direction of groundwater flow.
Page 3-14

2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
4.0 SUMMARY AND CONCLUSIONS
4.1 Groundwater Occurrence and Flow
A common finding from predictive groundwater flow and transport modeling is that
reducing the hydraulic head in the ash basin through decanting will reduce the vertical
and horizontal hydraulic gradients that drive constituent migration, with the greatest
reduction near the dam.
The following are conclusions pertaining to groundwater flow beneath the Mayo ash
basin:
• An upward vertical gradient is present at the upland edge of the ash basin
(Figure 3-8, Table 3-2).
• Horizontal flow primarily occurs across the basin, with downward flow from ash
pore water to the underlying saprolite and transition zone in the area where
water is ponded immediately upgradient of the ash basin dam.
• Downward vertical gradients occur at the ash basin dam (Figure 3-8).
• Upward vertical gradients occur beyond the dam near groundwater discharge
zones (Figure 3-8).
Groundwater level and quality data demonstrate that that groundwater flow and
related COI transport is toward Crutchfield Branch. The CSM will continue to evolve
and be updated to reflect new information as it becomes available.
4.2 Groundwater Quality
The following are conclusions pertaining to groundwater quality beneath and
downgradient of the ash basin based on data available through 2018:
• Variably reactive constituents, such as cobalt, are not suitable for delineating the
groundwater plume geometry and migration due to their sensitivity to changing
geochemical conditions in the groundwater system.
• Boron concentrations adequately describe and bound CCR influence on
groundwater at the Site.
• Boron occurrence in the saprolite, transition zone, and bedrock flow zones
confirm the CSM.
• The greatest boron concentrations in non -ash pore water wells are observed
beneath the ash basin in the transition zone and downgradient of the ash basin
dam in transition zone and shallow bedrock wells.
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
• The plume geometry of other COIs at the Site are generally contained within the
boron plume. Exceptions to this are caused by naturally occurring conditions or
Site conditions other than groundwater flow through the Site.
Page 4-2

2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
5.0 INTERIM MONITORING PLAN UPDATES
5.1 Optimization of the Monitoring Program
Duke Energy submitted an optimized IMP to NCDEQ on December 15, 2018. NCDEQ
approved the optimized IMP by email on December 21, 2018. The plan recommended
adjusting the well and water quality parameter lists to more efficiently monitor
groundwater conditions at the Site. After additional correspondence and discussion
with NCDEQ, Duke Energy submitted a revised optimized IMP on March 20, 2019
(Appendix E). The revised optimized IMP was approved on April 4, 2019, apart from
the removal of five deep bedrock wells installed in early 2019 (Appendix E). The deep
bedrock wells are under evaluation, and justification of this change to the IMP will be
provided at later date.
IMP analytical parameters were reduced to include the Site COI list and the federal
CCR Rule Appendix III and Appendix IV parameter lists beginning Quarter 1 of 2019. A
summary of the rationale for reducing the IMP well counts is provided below.
Wells critical to the IMP were identified in the following locations:
• Between CCR source areas and downgradient surface water bodies.
• At the Site compliance boundary to verify plume stability.
• At existing plume boundaries to detect plume expansion or contraction.
• Along geochemical flow transects to monitor plume stability, support the
geochemical model, and confirm horizontal and vertical distribution trends.
The optimized IMP well list is divided into quarterly and semiannual sampling
schedules. For 2019, site wells are sampled in the following manner:
• Background wells - semiannually
• Peripheral monitoring wells - semiannually
• Wells along flow transect - semiannually
• Downgradient wells used in model simulations - semiannually
• Wells with increasing COI concentrations - quarterly
New wells installed as part of the CAMA program will be monitored quarterly for at
least four quarters for the full suite of CAMA parameters listed in the optimized IMP.
After four quarterly events, Duke Energy will re-evaluate the monitoring frequency
Page 5-1

2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
and/or parameter list for the new wells with NCDEQ concurrence and revise the IMP if
needed.
The data evaluation in this annual report confirms the IMP for 2019 is appropriate. No
additional changes to the IMP are recommended at this time. It is recommended that
sampling continue in accordance with the IMP.
5.2 2019 Monitoring and Reporting Schedule
Duke Energy will sample the monitoring well network on a quarterly and semi-annual
basis during 2019 in accordance with the optimized IMP outlined above. New wells
installed throughout the year are anticipated to be added to the monitoring network
and quarterly sampling program. To maximize data available for evaluation in the
CAP, an initial sample is collected from new wells after development has been
completed and verified (i.e., turbidity <10 NTU 24 hours after development).
Depending on timing of initial sample collection, variances in quarterly sampling
schedule may be requested to avoid collection of auto -correlated data. In general, the
sampling events are anticipated to occur in accordance with the following schedule:
• Quarter 1 (wells sampled quarterly) January 2019
• Quarter 2 (wells sampled semi-annually and quarterly) April 2019
• Quarter 3 (wells sampled quarterly): July 2019
• Quarter 4 (wells sampled semi-annually and quarterly): October 2019
A quarterly, comprehensive data submittal to NCDEQ will occur in accordance with the
following schedule:
• Quarter 1 : March 2019
• Quarter 2: June 2019
• Quarter 3: September 2019
• Quarter 4: December 2019
(January 2019 data)
(April 2019 data)
(July 2019 data)
(October 2019 data)
Data from the 2019 IMP will help to refine and support groundwater quality,
occurrence, and flow evaluations as conditions change due to decanting of the basin in
the near future.
The list of Site -specific COIs for inclusion into the CAPs is currently undergoing review
using the COI management approach presented to the NCDEQ on March 15, 2019. COIs
proposed for management under the CAP would be based on:
Page 5-2

2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
• Comparing constituent concentrations to regulatory standards and/or
background values
• Evaluating each constituent's relative mobility
• Reviewing constituent distribution in groundwater based on geochemical
conditions
• Comparing each constituent's relative concentration observed in ash pore water
to the concentration observed in groundwater
• Evaluating constituent concentration trends over time
The results of this review will be presented in the CAP and may result in proposed
modifications to the monitoring program at that time.
Page 5-3

2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
6.0 REFERENCES
Harned, D., and Daniel, C., 1992. The transition zone between bedrock and regolith:
Conduit for contamination. In Daniel, C.C., White, R., and Stone, P., eds.,
Groundwater in the Piedmont, Proceedings of a Conference on Ground Water in
the Piedmont of the Eastern United States, Charlotte, N.C., Oct. 16-18, 1989.
Clemson, SC: Clemson University (336-348).
Duke Energy, June 10, 2015. Low Flow Sampling Plan, Duke Energy Facilities, Ash
Basin Groundwater Assessment Program, North Carolina.
General Assembly of North Carolina, 2014. Coal Ash Management Act of 2014. Senate
Bill 729, Ratified Bill (Session 2013) (SB729).
Izquierdo, M. and Querol, X., 2012. Leaching behaviour of elements from coal
combustion fly ash: an overview. International Journal of Coal Geology 94 (2012):
(pp. 54-66).
LeGrand, H. (1988). Region 21, Piedmont and Blue Ridge. In: J. Black, J. Rosenshein, P.
Seaber, ed. Geological Society of America, 0-2, (pp. 201-207).
LeGrand, H. (1989). A conceptual model of ground water settings in the Piedmont
region, in groundwater in the Piedmont. In: Daniel C., White, R., Stone, P., ed.
Ground Water in the Piedmont of the Eastern United States (pp. 317-327).
Clemson, SC: Clemson University.
LeGrand, H. E. 2004. A Master Conceptual Model for Hydrogeological Site
Characterization in the Piedmont and Mountain Region of North Carolina, A
Guidance Manual, North Carolina Department of Environment and Natural
Resources Division of Water Quality, Groundwater Section.
Multi -Agency Radiological Laboratory Analytical Protocols Manual (MARLAP), July
2004. MARLAP Manual Volume I: Chapter 8, Radiochemical Data Verification
and Validation.
NCDEQ, May 1, 2017. Correspondence to Duke Energy, Subject: Response to the
February 2, 2017 Letter from Duke Energy, Revised Interim Monitoring Plans for
14 Duke Energy Facilities.
NCDEQ, 2017. Guidelines for the Investigation and Remediation of Soil and
Groundwater Contamination.
Page 6-1

2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
NCDEQ, May 7, 2018. Correspondence to Duke Energy, Subject: 2017 Comprehensive
Site Assessment Update Comments - Mayo Steam Electric Plant.
NCDEQ, September 28, 2018. Correspondence to Duke Energy, Subject: Revised Interim
Monitoring Plans for 14 Duke Energy Facilities, 41hQuarter 2018.
Pierce, W. G. (1944). Cobalt -Bearing Manganese Deposits of Alabama, Georgia, and
Tennessee. Strategic Minerals Investigations, 1943 (pp. 265-285). Washington
D.C.: United States Department of Interior -Geologic Survey.
Polizzotto, M., Amoozegar, A., Austin, R., Bolich, R., Bradley, P., Duckworth, O., &
Hesterberg, D. (2015). Surface and Subsurface Properties Regulating Manganese
Contamination of Groundwater in the North Carolina Piedmont. Raleigh, NC:
UNC-WRRI.
SynTerra. (2015a). Comprehensive Site Assessment Report - Mayo Steam Electric Plant -
September 2, 2015. Roxboro, NC.
SynTerra. (2015b). Corrective Action Plan - Part 1: Mayo Steam Electric Plant -
December 1, 2015. Roxboro, NC.
SynTerra. (2016a). Corrective Action Plan - Part 2: Mayo Steam Electric Plant - February
29, 2016. Roxboro, NC.
SynTerra. (2016b). Comprehensive Site Assessment, Supplement 1 - Mayo Steam
Electric Plant - July 7, 2016. Roxboro, NC.
SynTerra. (2017b). 2017 Comprehensive Site Assessment Update - Mayo Steam Electric
Plant - October 31, 2017. Roxboro, NC.
SynTerra. (2018). Preliminary Updated Groundwater Flow and Transport Modeling
Report for Mayo Steam Electric Plant, Roxboro, NC.
United States Environmental Protection Agency, November 2002, Guidance on
Environmental Data Verification and Data Validation.
United States Environmental Protection Agency, January 2017a. National Functional
Guidelines for Organic Superfund Methods Data Review.
United States Environmental Protection Agency, January 2017b. National Functional
Guidelines for Inorganic Superfund Methods Data Review.
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
United States Environmental Protection Agency, November 2017 (Phase I) and July
2018 (Phase II). Test Methods for Evaluating Solid Waste: Physical/Chemical
Methods (SW-846), Update VI.
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2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
FIGURES

r n
1 MAYO STEAM ASH BASIN COMPLIANCE •;a ! p �'
ELECTRIC PLANT BOUNDARY
:i
PARCEL LINE J r
fFRI1 r—^ ^ 3�:
VIRGINIA. ^ _ 1 ^ IfALiFAX-
f�`0� _
NORTH CAROLINA� . - - - i � _ YERS C� J
APPROXIMATE ASH BASIN
WASTE BOUNDARY
r' 100• RIGHT-OF-WAY
WASTE WATER
—TREATMENT BASIN
CCP MONOFILL
FGD
Z*APPROXIMATE 1981 '
�\ �4P PONDS C&D LANDFILL r If
LINED RETENTION y* LOW VOLUME
BASIN AREAiL
PONDS
APPROXIMATE FUTUREASH BASIN WASTE BOUNDARY_ t rr A
(SEE NOTES, THIS DRAWING) 1� ,/
`�i� / POWER PLANT ^
Y COAL PILE AREA GYPSUM PAD AREA?
1-17
J
�• � ��, � • �� 1. ��V : ,�Sr,�•" �� � � �}�
d Cerr .c .. ). • ��, �. L�
$M "y97 " .fir-, •� �, � �-�:,. I. ,.
Pr r
_ �_ C _S3D • 1� �" � ♦ 1
NOTES: _ •` w�
2017 USGS TOPOGRAPHIC MAP, QUADRANGLE NAME, CLUSTER SPRINGS, QUAD 1
36078E8, QUADRANGLE, OBTAINED FROM ARCGIS ONLINE, APRIL 25, 2019. r __ �� lL - /„•. �;
j
AREA OF INVESTIGATION THAT DETERMINED SETTLED CCR MATERIAL --, • '+ � 4LJ.i � .. -
IS NOT PRESENT IN THIS AREA OF THE ASH BASIN. A FUTURE
IS INCLUDED
/� __- ` `T •, st.6'
REPRESENTATIVE ASH BASIN WASTE AND COMPLIANCE BOUNDARY IS INCLUDED IN THE MAYO NPDES PERMIT NC0038 PART 1, S.)
ATTACHMENTA FIGURE 1 AND ATTACHMENT B FIGURE 1.1 DATEDD JULJULY 13, 2018.
PERSON COUNTY FIGURE 1-1
14' SITE LOCATION MAP
synTerra W/NSTON-SALEM 2018 CAMA ANNUAL INTERIM MONITORING REPORT
• RALE/GH MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC
DUKE CHARLOTTE'• ROXBORO, NORTH CAROLINA
ENERGY DRAWN BY: A. ROBINSON DATE: 4/26/2019 1,000 0 1,000 2,000
PROGRESS PROJECT MANAGER: J. WYLIE CONTOUR INTERVAL: 20 Ff GRAPHIC SCALE IN FEET
CHECKED BY: P. ALTMAN MAP DATE: 2016

t �
•
/ • CCR-1045
%CCR-103BR
CCR-104BR
• • / MW-104BRL
W-104BRM
.�•MW-2
aT If PZ-1A
/ MW-105BRL
CCR-102BR-♦, MW-105BRM
/ CCR-105S
,
\ / CCR-105D
CCR-105BR
NORTH CAROLINA-VIRGINIA STATE LINE
HALIFAX COUNTY ,.. (APPROXIMATE)
__— —__—__—__—_____—__—__—__—_____—__—__—_____—__—__—__—__—__—__—__—__—__—__—_ —--
/ W-15BR PERSON COUNTY
CW-3 MW-16S
MW-3BR
CCR-109BR MW-166R �'
CCR-106BR
CW-2D-- •�• r r
LAKE RD-
MW-3 _ �MnvD ,
7CV
_6
9
MW-6BR ,
♦ MW-8BR _
... . .
P-3 CCR-107BR MW-8D
P-4
P-3A P-4A MW-107BRM (l MW-8S `♦
MW-107BRL
CCR-108BR BR
'• MW-17BR cmin
,.
�\ ♦1 1 ABMW-1 I � .�
ABMW-2 ABMW-3 e♦ CW-1
ABMW-2BR ABMW-3S `o �CW-1D
ABMW-2BRL
,
�\\� ' 1 ♦ Im
��` �►� MW-19BR
11 `1 ,.- r �`� • �
of . �L�•
I I Imo, �-- �� •
Ar
/ I , O ♦ CCR-101S-B APPROXIMATE FUTURE ASH BASIN WASTEBOUNDARY
/ , I 1 # (SEE NOTES, THIS DRAWING)
CCR-101 D-B
MW-11BR
R.O.W. 1700'
,
NOTES:
THE WATERS OF THE US HAVE NOT BEEN APPROVED BY THE US ARMY
CORPS OF ENGINEERS AT THE TIME OF THE MAP CREATION. THIS MAP IS
NOT TO BE USED FOR JURISDICTIONAL DETERMINATION PURPOSES. THE
WETLANDS AND STREAMS BOUNDARIES WERE OBTAINED FROM AMEC
FOSTER WHEELER ENVIRONMENTAL & INFRASTRUCTURE, INC. NATURAL
RESOURCE TECHNICAL REPORT FOR MAYO STEAM ELECTRIC PLANT
DATED JANUARY 20, 2014.
AREA OF INVESTIGATION THAT DETERMINED SETTLED CCR MATERIAL IS
NOT PRESENT IN THIS AREA OF THE ASH BASIN. A FUTURE
REPRESENTATIVE ASH BASIN WASTE AND COMPLIANCE BOUNDARY IS
INCLUDED IN THE MAYO NPDES PERMIT NCO038377 PART I, 5.A.(18.)
ATTACHMENTA FIGURE 1 ANDATTACHMENT B FIGURE 1.1 DATED JULY
13, 2018.
AERIAL PHOTOGRAPHY OBTAINED FROM GOOGLE EARTH PRO ON
SEPTEMBER 27, 2017. AERIAL WAS COLLECTED ON JUNE 13, 2016.
DRAWING HAS BEEN SET WITH A PROJECTION OF NORTH CAROLINA
STATE PLANE COORDINATE SYSTEM FIPS 3200 (NAD83/2011).
MW-12S
MW-12D
I
• • ,
> I3
� MULLINS LN
N �
o
OV
101
synTerra
ENERGY
PROGRESS
400 200 0 400 800 1,200
GRAPHIC SCALE IN FEET
148 RIVER STREET, SUITE 220
GREENVILLE, SOUTH CAROLINA 29601
PHONE [phone]
DRAWN BY: A. ROBINSON DATE: 04/30/2019
PROJECT MANAGER: J. WYLIE
CHECKED BY: E. KINSEY
MONITORING WELL IN
MONITORING WELL IN SAPROLITE
MONITORING WELL IN TRANSITION ZONE
MONITORING WELL IN BEDROCK
MONITORING WELL IN ASH PORE
MONITORING WELL
C PIEZOMETER IN SAPROLITE
C PIEZOMETER IN TRANSITION ZONE
C PIEZOMETER IN BEDROCK
• WATER SUPPLY WELL
APPROXIMATE ASH BASIN WASTE
WASTEWATER TREATMENT BASIN
LINED RETENTION BASIN
- - - ASH BASIN COMPLIANCE BOUNDARY
HIGHWAY 501 RIGHT-OF-WAY (DUKE ENERGY
PROPERTY)
DUKE ENERGY PROGRESS MAYO PLANT SITE
BOUNDARY
3 STREAM (AMEC NRTR)
EFFLUENT CHANNEL
0 WETLAND (AMEC NRTR)
FIGURE 1-2
SITE MAP WITH MONITORING WELL LOCATIONS
18 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC
ROXBORO, NORTH CAROLINA

LEGEND
NOTES:
�500
WATER LEVEL IN SURFICIAL ZONE (NAVD 88, FEET)
PARCEL LINE DUKE ENERGY(APPROXIMATE)
1. WATER LEVELS COLLECTED BY SYNTERRA, NOVEMBER 05 & 06, 2018.
2. NOT ALL UTILITIES ARE IDENTIFIED ON THIS DRAWING. THE UTILITIES SHOWN ON THIS DRAWING
INFERRED WATER LEVEL IN SURFICIAL ZONE 188,FEET) — —
NORTHCAROLINA-VIRGINIASTATELINE(APPROXIMATE)
ARE VISUAL AIDS TO LOCATE THE STREAMS AND WETLANDS IN THE FIELD. THE HORIZONTAL
QIIII MW-12S
WELL I D N SURFICIAL ZONE
HIGHWAY 501/RAILROAD RIGHT OF WAY (DUKE ENERGY PROPERTY)
LOCATION AND VERTICAL LOCATION HAVE NOT BEEN FIELD LOCATED ON ANY UTILITIES AND THE
SHOWN LOCATIONS ARE APPROXIMATE.
555.04
WATER LEVEL IN SURFICIAL ZONE (NAVD 88, FEET)
O P1
PIEZOMETER ID IN SURFICIAL ZONE
— ASH BASIN 500 ft COMPLIANCE BOUNDARY
3. THE TOPOGRAPHY IS SHOWN FOR REFERENCE PURPOSES ONLY AND SHOULD NOT BE USED FOR
DESIGN OR ENGINEERING PURPOSES. TOPOGRAPHY IS BASED ON LIDAR BARE EARTH DATA
442.74
WATER LEVEL IN SURFICIAL ZONE (NAVD 88, FEET)
ASH BASIN WASTE BOUNDARY (APPROXIMATE)
OBTAINED FROM THE NORTH CAROLINA SPATIAL DATA SITE AT
https*.//sdd.nc.gov/sdd/DataDownload.aspx
ABMW 1
MONITORING WELL IN ASH PORE WATER
SURFACE WATER (AERIAL PHOTOGRAPH &TOPOGRAPHIC MAP BASED)
4. THE WATERS OF THE US HAVE NOT BEEN APPROVED BY THE US ARMY CORPS OF ENGINEERS AT
Ql MW 3
MONITORING WELL IN ALLUVIUM MATERIAL ��
STREAM
THE TIME OF THE MAP CREATION. THIS MAP IS NOT TO BE USED FOR JURISDICTIONAL
DETERMINATION PURPOSES. THE WETLANDS AND STREAMS BOUNDARIES WERE OBTAINED
FMW-31
MONITORING WELL IN TRANSITION ZONE
SURFACE WATER FLOW DIRECTION
FROM All FOSTER WHEELER ENVIRONMENTAL& INFRASTRUCTURE,INC.
NATURAL RESOURCE TECHNICAL REPORT FOR MAYO STEAM ELECTRIC PLANT DATED
MW 14BR
MONITORING WELL IN COMPETENT BEDROCK
APPROXIMATE ASH BASIN FREE PONDED WATER
1ANUARY20,2014.
5. AREA OF INVESTIGATION THAT DETERMINED SETTLED CCR MATERIAL IS NOT PRESENT IN THIS
AP-6L30
PIEZOMETER IN ASH PORE WATER
NPDES REGULATED WATER FEATURE
AREAOFTHEASH BASIN. A FUTURE REPRESENTATION ASH BASIN WASTE AND COMPLIANCE
C 1
PIEZOMETER IN BEDROCK
BOUNDARY IS INCLUDED IN THE MAYO NPDES PERMIT NCO038377 PART I, S.A. (18.)
DEP
WETLAND BY AMEC FOSTER WHEELER
ATTACHMENT A FIGURE 1 AND ATTACHMENT B FIGURE 1.1 DATED JULY 13, 2018.
O P1A
PIEZOMETER IN EARTH DAM (FILL)
STREAM BY AMEC FOSTER WHEELER
MY-03
WATER SUPPLY WELL
__ CULVERT LOCATION
OUTFALL 002
NPDES OUTFALL (APPROXIMATE) 54o
TOPOGRAPHIC CONTOUR (10' INTERVAL)
TOPOGRAPHIC CONTOUR (2' INTERVAL)
♦�
GROUNDWATER FLOW DIRECTION
Ramwl •
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DRAWN BY: JOHN CHASTAIN\ C. NEWELL FIGURE 3-1
CHECKED BY: E. KINSEY WATER LEVEL MAP
-1 (SHALLOW WIL) SURFICIAL FLOW ZONE
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LEGEND
NOTES:
� 500 �
WATER LEVEL IN TRANSITION ZONE (NAVD 88, FEET)
PARCEL LINE DUKE ENERGY (APPROXIMATE)
1.
WATER LEVELS COLLECTED BYSYNTERRA, NOVEMBER 05 & 06, 2018.
2.
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WATER LEVEL INTRANSITION ZONE ,__
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AREVISUALAIDSTO LOCATE THE STREAMS AND WETLANDS IN THE FIELD. THE HORIZONTAL
!9
CW-3
CW-3
WELL ID I N TRANSITION ZONE
HIGHWAY 501/RAILROAD RIGHT OF WAY (DUKE ENERGY PROPERTY)
LOCATION AND VERTICAL LOCATION HAVE NOT BEEN FIELD LOCATED ON ANY UTILITIES AND THE
SHOWN LOCATIONS ARE APPROXIMATE.
419.41
WATER LEVEL IN TRANSITION ZONE (NAVD 88, FEET)
— ASH BASIN 500 ft COMPLIANCE BOUNDARY
3.
THE TOPOGRAPHY IS SHOWN FOR REFERENCE PURPOSES ONLY AND SHOULD NOT BE USED FOR
ABMW 1
MONITORING WELL IN ASH PORE WATER
DESIGN OR ENGINEERING PURPOSES. TOPOGRAPHY IS BASED ON LIDAR BARE EARTH DATA
ASH BASIN WASTE BOUNDARY (APPROXIMATE)
OBTAINED FROM THE NORTH CAROLINA SPATIAL DATA SITE AT
� MW-3
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https://sdd.nc.gov/sdd/DataDownload.aspx
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MW-12S
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SURFACE WATER FLOW DIRECTION
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JANUARY20,
C DEP-1
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5.
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STREAM BY AMEC FOSTER WHEELER
OUTFACE 002
NPDES OUTFACE (APPROXIMATE)
----------
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LEGEND
NOTES:
500
WATER LEVEL IN BEDROCK ZONE (NAVD 88, FEET) —
PARCEL LINE DUKE ENERGY (APPROXIMATE)
1. WATER LEVELS COLLECTED BYSYNTERRA, NOVEMBER 05 & 06, 2018.
2. NOTALL UTILITIESARE IDENTIFIED ON THIS DRAWING. THE UTILITIES SHOWN ON THIS DRAWING
INFERRED WATER LEVEL IN BEDROCK ZONE (NAVD 88, FEET) — —
NORTH CAROLINA - VIRGINIA STATE LINE (APPROXIMATE)
AREVISUALAIDSTO LOCATE THE STREAMS AND WETLANDS IN THE FIELD. THE HORIZONTAL
MW 2
WELL ID I N BEDROCK ZONE
HIGHWAY 501/RAILROAD RIGHT OF WAY (DUKE ENERGY PROPERTY)
LOCATION AND VERTICAL LOCATION HAVE NOT BEEN FIELD LOCATED ON ANY UTILITIES AND THE
SHOWN LOCATIONS ARE APPROXIMATE.
434.53
WATER LEVEL IN BEDROCK ZONE (NAVD 88, FEET)
— ASH BASIN 500 ft COMPLIANCE BOUNDARY
3. THE TOPOGRAPHY IS SHOWN FOR REFERENCE PURPOSES ONLY AND SHOULD NOT BE USED FOR
ABMW 1
MONITORING WELL IN ASH PORE WATER
DESIGN OR ENGINEERING PURPOSES. TOPOGRAPHY IS BASED ON LIDAR BARE EARTH DATA
ASH BASIN WASTE BOUNDARY (APPROXIMATE)
OBTAINED FROM THE NORTH CAROLINA SPATIAL DATA SITE AT
Qii MW-3
MONITORING WELL IN ALLUVIUM MATERIAL
httPs:Hsdd.nc.gov/sdd/DataDownload.aspx
SURFACE WATER (AERIAL PHOTOGRAPH & TOPOGRAPHIC MAP BASED)
4. THEWATERSOFTHEUSHAVE NOT BEENAPPROVEDBYTHEUSARMYCORPSOFENGINEERSAT
MW12S
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THETIMEOFTHE MAP CREATION. THIS MAP IS NOTTO BEUSED FOR JURISDICTIONAL
STREAM AERIAL PHOTOGRAPH &TOPOGRAPHIC MAP BASED
( )
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CW-3
MONITORING WELL IN TRANSITION ZONE
FROM AMEC FOSTER WHEELER ENVIRONMENTAL & INFRASTRUCTURE, INC.
SURFACE WATER FLOW DIRECTION
NATURAL RESOURCE TECHNICAL REPORT FOR MAYO STEAM ELECTRIC PLANT DATED
c AP 6L30
PIEZOMETER IN ASH PORE WATER
JANUARY20, 2014.
APPROXIMATE ASH BASIN FREE PONDED WATER
C DEP 1
PIEZOMETER IN BEDROCK
5. AREA OF INVESTIGATION THAT DETERMINED SETTLED CCR MATERIAL IS NOT PRESENT IN THS
NPDES REGULATED WATER FEATURE
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O P1A
PIEZOMETER IN EARTH DAM (FILL)
BOUNDARY IS INCLUDED IN THE MAYO NPDES PERMIT NCO038377 PART I, S.A. (18.)
WETLAND BY AM EC FOSTER WHEELER
ATTACH M ENT A FIGURE 1 AND ATTACHMENT B FIGURE 1.1 DATED JULY 13, 2018.
• MY-03
WATER SUPPLY WELL
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1
} r
r
x 5-
L.
i t ,
l
/r
r
_ r
0
S
r
4,
r •
y I
. `•III .III 1I �` � � � i4, .r r .
L
RYA
FA
r
MAYO RESERVOIR
WL ± 433'
W WATER INTAKE
• ��� �\'� i� A °ter j ,, f .
-ter
",..._ 1�... a � :!,+• ..-.
t'
�` � ����JJ • `,ell '� � • � �� .� >, _
dp ..
l e• • • • •FIGURE 3-3
PROJECTCHECKED BY: E. KINSEY WATER LEVEL MAP
LAYOUT NAME: FIGURE 3-3 (BEDROCK WL) BEDROCK FLOW ZONE
f f `GRAPHIC SCALE (NOVEMBER 05 • 1618
l •� , i� s+ll ' I,li�,.. ...�+I� .� ��. _ ,ti s • Ise _ ' MONITORING
•. REPORT
.•

550
c 500
350 +-
01/15
07/15 01 /16 07/16 01 /17 07/17 01 /18 07/18 01 /19
Date
0 MW-12D ♦ - ABMW-2BRL ❑ MW-16D
p MW-12S • CW-2 O MW-16S
❑ ABMW-2 0 CW-2D
ABMW-2BR V MW-16BR
Notes:
1. Hydrographs are drawn from water levels measured in the field at each monitoring well
during routine monitoring events.
2. All water levels are in feet (ft), NAVD 88.
148 RIVER STREET, SUITE 220
GREENVILLE, SOUTH CAROLINA 29601
PHONE: [phone]
p�^
�TGI ra
www.synterracorp.com
:.DUKE
DRAWN BY: ENK DATE: 4/3/2019
PROJECT MANAGER: JAW
►. ENERGY
CHECKED BY: JAW
FIGURE 3-4
HYDROGRAPHS
2018 CAMA ANNUAL INTERIM
MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC
ROXBORO, NORTH CAROLINA

lot
COAL
PILE —
Notes: � � � ► � � � � �' _ -� �, .. �� i ..,,�R. r — _ — l ' � �.
Velocity magnitudes in feet per day (ft/day).
Velocity vectors are in three dimensions.
Velocity vector directions shown as black arrows.
Source: Preliminary Updated Groundwater Flow and Transport Modeling Report for Mayo Steam Electric Plant, Roxboro, NC, November 2018 (Murdoch, Yu, Graziano & Falta, Revised January 2019).
LEGEND
0.1-0.2
ft/day
148 RIVER STREET, SUITE 220
FIGURE 3-5
■0
— 0.001
ft da
/ y
0.2-0.3
ft/day
GREENVILLE, SOUTH CAROLINA 29601
PHONE:[phone]
FLOW VELOCITY VECTORS AND MAGNITUDES
■
0.001-0.01
ft/day
0.3-0.4
ft/day
synTerra
www.synterracorp.com
SURFICIAL FLOW ZONE
■
0.01-0.05
ft/day
0.4-0.5
ft/day
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
0.05 — 0.075
ft/day
0.5 -1.0
ft/day
�� DUKE
`�
DRAWN BY: J. EBENHACK DATE: 4/12/2019
DUKE ENERGY PROGRESS, LLC
0.075 — 0.1
ft/day
.
1.0t
ft/day
ENERGY
PR('
PROJECT MANAGER: J.WYLIE
CHECKED BY: E. KINSEY
ROXBORO, NORTH CAROLINA

�� 1V � rr✓ram r- .�
tX.4
ntiti b� `�� L� G ti �• ~` �g f/ �..'� P f ! r l7 t �;��. f'r 8.11�j ~ �' t i r i
+� � ti ti `• ., �•w1.`.`.•,\. ••t 1 f%/J��-,. _ f P � +..�•. }-•.iifi
ASH
BASIN
� .�� t t t 1 l r, �����ti�♦ `� 1 � j � \`� ��� � -, 93 ti i r �. � r.� ���'J, 111� ��1� PsI
� / f .err • a �- ti� � IS
ti
jf 1 rT ¢•r't� 1 t�� • -�': ti �� ����� ` ti I `f
�. rl S tilt 1 l � 1 1 r� ,� •,'\'� .♦ '. t
"` �'�_.-_~ • •r 1 r11 t 1 l fi � _r'�'l � � "r�� �*�.ti'����\ti�ti�� `��'� "_y Y ry �� l-w ���'�� ti
r�Y•�--"''- • rill\ 1't t ��f>t] r �•.♦\♦\����♦ ♦ ''�,r• � '' 1 •�
r��`" ` , . 1 I L l 1 t P , t t ' -, '� ti�� � \ti s ► '� - t 1 ; 4%
MAYO
-- -� Tm J f `>>•�>>.�f .\\\�ti\\\\\\\ \ PLANT
COAL
PILE
��-
Notes:
Notes:
Velocity magnitudes in feet per day (ft/day).
Velocity vectors are in three dimensions.
Velocity vector directions shown as black arrows.
Source: Preliminary Updated Groundwater Flow and Transport Modeling Report for Mayo Steam Electric Plant, Roxboro, NC, November 2018 (Murdoch, Yu, Graziano & Falta, Revised January 2019).
LEGEND
0.1-0.2
ft/day
148 RIVER STREET, SUITE 220
FIGURE 3-6
■0
— 0.001
ft da
/ y
0.2-0.3
ft/day
GREENVILLE, SOUTH CAROLINA 29601
PHONE:[phone]
FLOW VELOCITY VECTORS AND MAGNITUDES
■
0.001-0.01
ft/day
synTerra
TRANSITION ZONE FLOW ZONE
■
0.01-0.05
ft/day
0.3-0.4
0.4-0.5
ft/day
ft/day
www.synterracorp.com
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
0.05-0.075
ft/day
0.5-1.0
ft/day
��DUKE
`*'
DRAWN BY: J.EBENHACK DATE: 4/12/2019
DUKE ENERGY PROGRESS, LLC
0.075 — 0.1
ft/day
.
1.0t
ft/day
ENERGY
FR.'
PROJECT MANAGER: J. WYLIE
CHECKED BY: E. KINSEY
ROXBORO, NORTH CAROLINA

1 'l 'tI fl.ft��-�.� � � �• > t �, 1 >ti ���a 'r...�%if
1�
rr 1 jam,. ".. • , . ��-+>>' P qS._� .� -- j
`' r , .• . rr�__�..-,'Y /r tom--_ _.�-- � 1 � o � 1 l
� r � ^� � . _ - r r t '� ;P� �� jt' :�ti ��- � ` + \�� Sr' r , 1 �•- .�r,f rf � Y Y ti
z 1 1r
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\ � t t tip-' f` � - � .= �ti��ti P��•. � 1 � � r��.�r
• ` \\\\\ +\� \'�
tiL\` 1�ti�-: .. �•. . r� ?: ---'� _ 1 r r f �.
_ � 4��`.S'`+Y1•\\\11�1\,`` Ii/". •'irl�r:.a'l � r✓��•j�~~~ �� f ` P ..��' f.
� � _��-- r~...a�"-`• �.`� • .....,�4:"\ti\\k.• •, t t f 5 •A.1.��� 1 ..«��� r f j % � - .1 _., •4..
\ '- �t r� : f frtt t t { t1. `v,��• • . ti t f BASIN\
a r rr,° l i t ,� ..�- ��������.R t r r 1 1 1 �� y�� \'.1•. t'�� r t '' ,�� ���1 ��
V- >
/ rl.�r ..� � ti•. \L •.rya\ y\ty\ti �""�-.��� � - �.� \ L%'�
MAYO
,� ��w.-��-� --.ter Pit•��� •� L� .. �'�� ti. \\\\\1ti 1�� � �S� � � � �, �\ ; ! ` � f'
-,_----���a � l; � rp P� N, y , •--�--".�� �, y 1\\ti�� �~ r �, f.. ti � �, a � � L 1
���� �f~ t. r PJf 1ti� � t PJ,p f jr �,.. �R�titi\"�\\\\�'�•� ti� ~ ti �_' "� f r - � .. �"'1`"_��� . , 1 t y'a l 1 1 f P r ..-.�.� ••:'• .�����\ti �� \ � � ti �` � -� � �„ r l r �
PLANT
�� ,���• �,�� ���tiZ�.�-_-_,� r fr,l����titi��,������ � ti s, � ,` , r r--.~`r�„ �`:,1 � ��� �, P Ir
PILE
Notes: � ~ ~ . � ~ •. '` � ,. '..� R � , t . P � � R •` Z t � , T t . _• -. —~r i _, -• -
Velocity magnitudes in feet per day (ft/day).
Velocity vectors are in three dimensions.
Velocity vector directions shown as black arrows.
Source: Preliminary Updated Groundwater Flow and Transport Modeling Report for Mayo Steam Electric Plant, Roxboro, NC, November 2018 (Murdoch, Yu, Graziano & Falta, Revised January 2019).
LEGEND
0.1-0.2
ft/day
148 RIVER STREET, SUITE 220
FIGURE 3-7
■0
— 0.001
ft da
/ y
0.2-0.3
ft/day
GREENVILLE, SOUTH CAROLINA 29601
PHONE:[phone]
FLOW VELOCITY VECTORS AND MAGNITUDES
■
0.001-0.01
ft/day
0.3-0.4
ft/day
synTerra
www.synterracorp.com
BEDROCK FLOW ZONE
■
0.01-0.05
ft/day
0.4-0.5
ft/day
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
0.05-0.075
ft/day
0.5-1.0
ft/day
��DUKE
`*'
DRAWN BY: J.EBENHACK DATE: 4/12/2019
DUKE ENERGY PROGRESS, LLC
0.075 — 0.1
ft/day
.
1.0t
ft/day
ENERGY
FR.'
PROJECT MANAGER: J. WYLIE
CHECKED BY: E. KINSEY
ROXBORO, NORTH CAROLINA

Ash Basin Ash Basin
Pond Dam
P f
... _ _ � � y 1 f f f � � � �� ri'JJ.•O�r/J/ f
/ t �
Notes: 4 ''7' _
Flow Velocity Vectors and Magnitudes through the Ash Basin and Dam Current Conditions `
Velocity Magnitudes in feet per day (ft/day).
Velocity vectors are in three dimensions.
Velocity vector directions shown as black arrows.' f=''
Vertical Exaggeration = 3xM..
Source: Preliminary Updated Groundwater Flow and Transport Modeling Report for Mayo Steam Electric Plant, Roxboro, NC, November
2018 (Murdoch, Yu, Graziano & Falta, Revised January 2019).
0 - 0.001 ft/day 148 RIVER STREET, SUITE 220 FIGURE 3-8
LEGEND 0.2 - 0.3 ft/day `� PHONE: [phone] GREENVILLE, SOUTH CAROLINA 29601 FLOW VELOCITY VECTORS AND
0.001 - 0.01 ft/day
0.3 - 0.4 ft/day 5�'lTerrd MAGNITUDES THROUGH DAM
0.01 - 0.05 ft/day www.synterracorp.com 2018 CAMA ANNUAL INTERIM
0.4 - 0.5 ft/day 0.05 - 0.075 ft/day DRAWN BY: J. EBENHACK MONITORING REPORT
0.5 - 1.0 ft/day �� DUKE DATE: 4/11/2019 MAYO STEAM ELECTRIC PLANT
(
0.075 - 0.1 ft/day 1+ ft/day � ENERGY. CHOJECTIVAN GER: JYWYUE DUKE ENERGY PROGRESS, LLC
0.1 - 0.2 ft/day ROXOBORO, NORTH CAROLINA

A A'
NORTHWEST SOUTHEAST
DUKE ENERGY MAYO STEAM ELECTRIC PLANT PROPERTY
a
ASH BASIN COMPLIANCE BOUNDARY
Lo PROFILE BASED ON HISTORIC a
USGS TOPOGRAPHIC MAP
ASH BASIN WASTE BOUNDARY
m LANDFILL
o s It
K
� S
'S tii r z .r ��+r vP`
M ZO m n
LSi
o �tl �^ PROFILE BASED ON HISTORIC
o�__ U �Y '�luf t ylyi^yrt� p /� /USGS TOPOGRAPHIC MAP
ASH BASIN tI\
%/� it v;r+-- _TovoFDAMass'--___-- _—REGOLITH�
----------------------------------------
WATER ELEVATION=480'---------- —
ASH �i� !,\/1\I `�\/�� I r \
MAYO RESERVOIR
TOP OF DAM 444
_ t \ / \ _ _ \ / - \ / �r r• \ \ i \ / — l i I \ !! REGOLITH
I 1 \ / / 1 \ / \—\ \ \ / GENERALIZED GROUNDWATER I \ / _ \ I / \ — \ I \ / _ \ \ / — \ IIP
WATER ELEVATION=433
GROUNDWATER / / \ / _ \ / \FLOW DIRECTION / \ / 1 / \ \ / \ / 1 / \ / \ I / 1 / / \ / / 1
'FLOW DIRECTION / / �1 / - - _ / \ / 1 / / /
—�� \ — — 1 \ — — 1'/ ASH / \ \ — 1 �/\—/ \ 1'/ —� \ — 1'/�—/—\ \ — 1'/�—//`—/ \ \%A
3 p \ I / \ i \ / I i \ i \ I / \ i \ / I \ \ I / \ i \_ �_� \ / I \ i \ I /�� \ / I i \ i \ / I / \ i \ / I i \ i \ I / \ irc�\ / I i \ i I / GENERALIZED \ \ /�
_ \' \ / — \ ♦ i /N pI>� / — \ \ i / — _ \' / — \ \ i / — _ \ / — \ \ i / _ \ \� \ \ i / — — \' ` � �► / — _ \ / — \ \ i / — _ \ / — �_ ,F .h — _ ♦ —GROUNDWATER z 'Al \
\/\I/1\/\/\I/\/\I/1\/\/\I/\/\I/1\/\/\I/1\/\/\/\/1\/\/\I/1\/\/\I/1/3o/\I/1\/\/\I/1\/\/\I/1\'\/\I/1\/ /¢�w/1\/\/\I/1\/FLOW DIRECTION
/FORMER CHANNEL OF 11 /\—_ \ \ /.� — — \ /\—_ \ 1 /\Z�>I� \—_ \ \ /.� — /.—_ \ 1 /.� — s1 zIQ Jw► \l_i�\\I \/I� —/\/—i`'\I./ /I\i / \ii\\I./I\—/\/_i\'\I•/ /I\,\l—/\I./I _/\/\\'\I�/ ;I\ /\ / /\I//1I,_/\l i/\I/1\/\_/\I/1�//\I//1\'/\_'\\I/1I\/\/\I// `/l\i/\I/` I �// 1\' /l\i/\I/1I�/BE�D/R\OIC/K1\'\/\I/1I _
CRUTCHFIELD BRANCH' PROFILE BASED ON HISTORIC
1qvo. \
USGS TOPOGRAPHIC MAP
PROFILE BASED ON HISTORIC — \
%` BEDROCK%\.//�I / \\ `BEDROCK\\ ;\. �I / \\\USGS TOPOGRAPHIC MAP
/ 7%
LEGEND
MW 16S
WELL IN ALLUVIUM MATERIAL
MW 12S
WELL IN SAPROLITE MATERIAL
MW 16D
WELL IN TRANSITION ZONE
MW 16BR
WELL IN COMPETENT BEDROCK
ABMW 2
WELL IN ASH PORE WATER
MY 1001
WATER SUPPLY WELL
_
GENERALIZED WATER TABLE
GENERALIZED GROUNDWATER
FLOW DIRECTION
GENERALIZED SUBSURFACE ASH
PORE WATER FLOW DIRECTION
— — —
LITHOLOGIC CONTACT
ASH
— ASH PORE WATER
BEDROCK
502.70' WATER LEVEL
ry ASH FLOW LAYER
WATER LEVEL ELEVATION
SURFICIAL FLOW LAYER GROUNDWATER
WELL WATER LEVEL ELEVATION
TRANSITION ZONE FLOW LAYER GROUNDWATER
WELL WATER LEVEL ELEVATION
BEDROCK FLOW LAYER GROUNDWATER
WELL WATER LEVEL ELEVATION
®j BORON CONCENTRATION IN ug/L
0116106i
1. DEPTH TO WATER GAUGED IN MONITORING WELLS ON NOVEMBER 5 & 6, 2018.
2. BORON CONCENTRATIONS ARE THE GEOMEAN FOR SAMPLES COLLECTED IN 2018.
3. THE NORTH CAROLINA 2L FOR BORON IS 700 Ng/L.
4. BACKGROUND THRESHOLD VALUE (BTV) FOR BORON IS 50 Ng/L WITHIN THE SHALLOW,
50 Ng/L DEEP, 50 Ng/L BEDROCK FLOW LAYERS.
5. ALL VERTICAL ELEVATIONS ARE MEASURED IN FEET, NORTH AMERICA VERTICAL DATUM (NAVD) OF 1988.
SOURCE INFORMATION:
0 125 250 500
HORIZONTAL SCALE: 1" = 500'
VERTICAL SCALE: 1" = 100'
5X VERTICAL EXAGGERATION
EXISTING GROUND SURFACE BASED ON A DRAWING PROVIDED BY THE WSP GROUP, TITLED "MAYO PLANT FINAL", DATED MAY 19, 2015.
HISTORIC GROUND SURFACE BASED ON THE 7-1/2' USGS TOPOGRAPHIC MAP FOR CLUSTER SPRINGS, VA DATED 1968.
PRIVATE WATER SUPPLY WELL INFORMATION WAS OBTAINED FROM A LIST PROVIDED BY DUKE ENERGY PROGRESS
16, VERTICAL EXAGGERATION 5X FIGURE 3-9
GENERAL CROSS-SECTION A -A'
WnTem 148 RIVER STREET, SUITE 220 2018 CAMA ANNUAL INTERIM MONITORING REPORT
GREENVILLE, SOUTH CAROLINA 29601
PHONE[phone] MAYO STEAM ELECTRIC PLANT
www.synterracorp.com rp. com
DUKE DUKE ENERGY PROGRESS, LLC
P ENERGY DRAWN DATE:04/25/2019 ROXBORO, NORTH CAROLINA
PROJECT MANAGER:JERRY WYLIE
LAYOUT: SECTION A -A'
PROGRESS

B--a
SOUTHWEST
—w---=A=ROL=TE---
SMALL
STREAM
PROFILE BASED ON 1968
USGS TOPOGRAPHIC MAP
v1
W
— \ COAL PILE AREA
0
0 0
DUKE ENERGY MAYO STEAM ELECTRIC PLANT PROPERTY
ASH BASIN COMPLIANCE BOUNDARY
- ASH BASIN WASTE BOUNDARY
J
v ci
D] CO
(n
N N
I?m
D] D7
D]
D7
Q Q
Q
Q
ASH BASIN
EARTHEN DAM u:I_)
(FILL)
TOP OF DAM 488
- N r
� O �
m � m
M m rr
-mmm-- B'
NORTHEAST
PROFILE BASED ON
1968 USGS
TOPOGRAPHIC MAP
_ _ _ uJ uJ
—� TRANSITION GENERALIZED G
T= 1♦�� r_T SLOW DIRECTION OUNDWgTER — — — �,��1 — �� — 1 L • WATER ELEVATION=480 Q a O O O O O r c B.
l \ / I / \l i l \ / I / \/ i l \ / i �� — — ASH � uJ
♦ \/ — _\/�/ / _\/\/� _ --- — fV N UUU Y m
------------ \
cq
\/I/\� \/I/\il\/I/\\ \/I/ it\/I/��l\/I/\il\/I/\\� \TIT'\i'T1-•�- M
♦ / \ / — _ \ / / — \ \ / / — — ♦ / — \ / / — — \ / \ / — \ \ / \ / — / — \ \ / / — _�' �-•— �� TRANSITION ASH
i\I/1\/\/\I/1//�/\I/1♦/\ \I \/\I/1`/\/\I/1`/�/\I/1`� I/1`/ /\I ♦/\/\I/1`i--/\I ♦T \?\'iT T� �•—.� ����—_ �,f cV cV
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� /♦—_ \ — 1 � /♦� — � — \ � /♦—_ \ — j /♦� — � — 1 � /♦—_ \ — \ � /♦� — � — \ � / — j /♦/ — i — \ % /`—_ \ — 1 � /`/ i \ l /` — \ — 1 / /♦/ i \ l /♦ — \ — 1 / /♦/ i 1 / /♦ \ 1 / /♦/'1 \�♦ T — � � � � U U
♦ \ /I \/ \ / /I — `/ i /I `� \ / \ /I — \/ i /I \l \ / ♦ /I — `/ i \ — / \ /I — \/ i /I `/ \ / \ /I — `/_' i / I / \/_� /I — \/_� i / I / `/_� \ /I — \l i / / \l ` /I _ \l i / I / \//T/ ; r" r .-� _
i\I/1♦/\/\I/1,/\/\I/1`/\\I/1�'\/\I/1`/\/\I/1,/\/\I/1`/\/\I/1�/\/\I/1`/\/\I/1�/\/\I/1`/\/\I/1,/\/\I/1`/\/\I/1�/\/\I/1/\/\I/1,/\/\I/1`/\/\I/1`/\/\I/1`/\�I/1�
ALLUVIUM
Ar
/ \\/ I / \`� / \♦/ I � \ i l \\/ I / \` l \♦/ I / \ i l \\/ I / \l \♦/ I / \ i l \\/ I / \/ \♦/ I / \ `. /I � `\ ♦/ \♦/ I / ` \\ /I � \\ \� /I / \\ � /`I � `\ � /\� /I / \\ � /\. /I � \\ /I � \\i �\\/ I / \/ \♦/ I / \ i l \\/ I / \`� l \♦/ I / \ / \`�,l \♦ � �T�Nsr� �
\I / 1 ♦ `\ / \BEDROCK / \ I / 1 ` \ \I / 1 ` / \I / 1 ♦ \ / \ I / 1 ♦ / \I / 1 ` \ / \I / 1 ` / \I / 1 \ / \ I / 1 ` / \I / 1 ` \ / \I / 1 ` / \ I / 1 ` \ / \I / 1 ` / \I / 1 \ / \ I / 1 ` / \ I / 1 ` \ / \I / 1 ` / \I / 1 ` \ / \ I / 1 ♦ \ / \I / \ \ \ \ / \ I / ��
/♦ \ — 1 /♦-- \ — 1 /♦—_ \ — % /♦-- \ — 1 /♦ \ — \ /♦-- \ — 1 /♦ \ — \ /♦—_ \ — 1 .BEDROCK j /♦-- \ — \' /♦ \ — 1 /♦—_ \ — \' /♦—_ \ — \ /♦—_ \ — 1 ' / r \ — 1 /♦—_ \ 1 /♦__ \ — \ /♦—_ \ — \ ' /♦__ \ — \ /♦—_ \ 1 /♦_ \ — 1 / /♦-- \ \' /♦—_ \ — /♦
\/1 \/\/\/ \/\I/1 \/♦/1/ \/\I/1`�\i\I/1/ \/\I/1` \/\I/1�/ %\I/1` \i\I/1�/ /\I/1` \/\I/1�/ %\I/1` \/\I/1�//\I/1♦/\i\I/1/��BEDROCK/\/\I/1���%\I/1`/\i\I/1/��/♦I/1 \/\I/1/��\\I/1`/\i\I/
l \�/ I / \\ i l \♦/ I / \ i l \\/ I / \` i l \♦/ I / \ i l \\/ I / \` l \♦/ I / \ i l \\/ I / \` i l \♦/ I / \ i l \\/ I / \\ l \♦/ I / \ i l \\/ I / \` l \♦/ I / \ i l \\/ I / \` i l \♦/ I / \ i l \\/ I / \\ i l \♦/ I / \ i l \\/ I / \` i l \♦/ I / \ i l \\/ I / \\ i l \♦/ I / \ i l \\/ / \` i l \♦/ I CRUTCHF/ELD \ i l \♦
/ 1 ` / I ♦ / — ♦ / I ♦ / — ♦ / I ♦ / — ♦ / I ♦ / — ♦ / I ♦ / — ♦ / I ♦ / — ♦ / I ♦ / — ♦ / I ♦ / — \ / I ♦ / — ♦ / I ♦ / — I -BRANCH I
ol
i \I / � ♦ \ � / \I / 1 ` � \ / \ I / 1 ` � \ / \I / 1 ` � \ / \I / 1 ` � \ / \ I / 1 ` � \ / \I / 1 ` � \ / \I / 1 ` � \ / \I / 1 ` � \ / \ I / 1 ` � \ / \I / 1 ` � \ / \I / 1 ` � \ / \ I / 1 ` � \ / \I / 1 ` � \ / \I / 1 ` � \ / \ I / 1 ` � \ / \ I / 1 ` � \ / \I / 1 ` � \ / \I / 1 ` � \ / \ I / 1 ` � \ / \I / 1 � \ / \I / 1 ` / \ / \ I / 1 ` / \ / \ I /
• �\\/ I / \`� / \♦/ I � \ i l \\/ I / \`� / \♦/ I / \ i l \\/ I / \`� l \♦/ I / \ i l \\/ I / \`� /`♦ /I / \\ � /`� /I � `\ \ /\\ /I / `\ � /`\ /I � \\ ♦ /\♦ /I / \\ � /`�//I � `\ \ /\\ /I / \\ � /`� /I � \\ ♦ /\♦ /I / `\ � /`\//I � `\ ♦ /\♦ /I / \\ � /`�//I � `\ � /`♦//I / `\ � /`♦// � \\ � /`♦ /I / \\' /`\/ I / `\' /\\
\/1 _\/\/\/ \/♦/1 \/\/1/ \/♦/\ \/\/1/ \/\/1 _\/\/1/ \/\I/1 \/\/\/ \/\I/1 \/\/\/ \/\I/1 /\/`/1/ \/\I/1 \/\/\/ \/\I/1 /\/`/1/ \/\I/1 \/♦/li/\/♦I/1 '\/\I/1��\/\I/1`/\/\I/
—
i \I / 1 ♦ \ \ / \I / 1 ♦ \ / \ I / 1 ` \ / \I / 1 ♦ \ / \I / 1 ` \ / \ I / 1 ♦ \ / \I / 1 ` \ / \I / 1 ♦ \ / \I / 1 ♦ \ / \ I / 1 ` \ / \I / 1 ` \ / \I / 1 ♦ \ / \ I / 1 ♦ \ / \I / 1 ` \ / \I / 1 ` \ / \ I / 1 ♦—\ / \ I / 1 ` \ / \I / 1 ` \ / \I / 1 ♦ \ / \ I / 1 \ \ / \I / 1 \ / \I / 1 ♦ \ / \ I / 1 ♦ \ / \ I /
4
LEGEND
0 125 250 500
NOTES
MW 16S
WELL IN ALLUVIUM MATERIAL
ASH FLOW LAYER
HORIZONTAL SCALE: 1" = 500'
VERTICAL SCALE: V= 100'
MW 12S
WELL IN SAPROLITE MATERIAL
WATER LEVEL ELEVATION
1. DEPTH TO WATER GAUGED IN MONITORING WELLS ON NOVEMBER 5 & 6, 2018.
5X VERTICAL EXAGGERATION
MW16D
WELL IN TRANSITION ZONE
V
SURFICIAL FLOW LAYER GROUNDWATER
2. BORON CONCENTRATIONS ARE THE GEOMEANFOR SAMPLES COLLECTED IN2018.
MW 16BR
WELL IN COMPETENT BEDROCK
WELL WATER LEVEL ELEVATION
3. THE NORTH CAROLINA 2L FOR BORON IS 700 pg/L.
ABMW 2
WELL IN ASH PORE WATER
V
TRANSITION ZONE FLOW LAYER GROUNDWATER
4. BACKGROUND THRESHOLD VALUE (BTV) FOR BORON IS 50 pg/L WITHIN THE SHALLOW,
MY-1001
WATER SUPPLY WELL
WELL WATER LEVEL ELEVATION
50 pg/L DEEP, 50 pg/L BEDROCK FLOW LAYERS.
GENERALIZED WATER TABLE
BEDROCK FLOW LAYER GROUNDWATER
5. ALL VERTICAL ELEVATIONS ARE MEASURED IN FEET, NORTH AMERICA VERTICAL DATUM (NAVD) OF 1988.
_
WELL WATER LEVEL ELEVATION
GENERALIZED GROUNDWATER
FLOW DIRECTION
BORON CONCENTRATION IN pg/L
SOURCE INFORMATION:
GENERALIZED SUBSURFACE ASH
PORE WATER FLOW DIRECTION
EXISTING GROUND SURFACE BASED ON A DRAWING PROVIDED BY THE WSP GROUP, TITLED "MAYO PLANT FINAL", DATED MAY 19, 2015.
HISTORIC GROUND SURFACE BASED ON THE 7-1/2' USGS TOPOGRAPHIC MAP FOR CLUSTER SPRINGS, VA DATED 1968.
- - -
LITHOLOGIC CONTACT
PRIVATE WATER SUPPLY WELL INFORMATION WAS OBTAINED FROM A LIST PROVIDED BY DUKE ENERGY PROGRESS
0
ASH
ASH PORE WATER
VERTICAL EXAGGERATION 5X FIGURE 3-10
BEDROCK
pm
GENERAL CROSS-SECTION B-B'
545.63'
WATER LEVEL
�Q
148 RIVER STREET, SUITE 220 2018 CAMA ANNUAL INTERIM MONITORING REPORT
GREENVILLE, SOUTH CAROLINA 29601
DUKE
4n
PHONE[phone] MAYO STEAM ELECTRIC PLANT
www.synterracorp.com
DUKE ENERGY PROGRESS, LLC
ENERGY DRAWN BY: C.NEWELL DATE:04/25/2019 ROXBORO, NORTH CAROLINA
PROJECT MANAGER: JERRY WYLIE
PROGRESS
LAYOUT: SECTION B-B'

E
•
}
+
+
.� •-
•
•
MW-16S
0 CCR-103S i
187.2
683 +
+
s
CCR-104S
+
-
338
s�
yyo 1 1 ,
r
1+ CCR-105S MW-3 �+
+1 + I 282 1089.4 ►y
1 1 I 1
I I d ■
`�� 1 1 •1 I ►
I
�� \ +r j r "-•�i � 1
• \ I I
ABMW-1 ABMW-2 / I
Rqi� I 5071.7 8486.7 A s
Oe ABMW-3 �+
r , 1962.3 ■►
ABMW-3S APO
I I 1314.7 0�
t ^ I ABMW-0
5900.0
ABMW-4X* 0
5290.0
' S r I ..w� I► I -R
A t --f , to , ► ' / . y`�
I I lyl • �..�
41
I . •I %
►fk I APPROXIMATE FUTURE ASH BASIN WASTE BOUNDARY
(SEE NOTES, THIS DRAWING)
CCR-101 S-BG'y
<50 r..
T 7 r I I
� I I
t R.C: W. 100'
� , I
I
<50
+ � . <50
,
r
ULLINS LN t , I
rIl ,
7
G �
400 200 0 400 800 1,200
GRAPHIC SCALE IN FEET
synTerra
148 RIVER STREET, SUITE 220
GREENVILLE, SOUTH CAROLI A 29601
PHONE
DUKE
www.s nterracor .com
terrac m.COM
DRAWN BY: A. ROBINSON DATE: 04/25/2019
ENERGY
,i
PROJECT MANAGER: J. WYLIE
PROGRESS
CHECKED BY: E. KINSEY
NORTH CAROLINA-VIRGINIA STATE LINE
(APPROXIMATE)
LEGEND
0
0
= mm =i
I
NOTES:
FIGURE 3-11
ISOCONCENTRATION MAP
GEOMEAN OF BORON IN SURFICIAL FLOW ZONE
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC
ROXBORO, NORTH CAROLINA

E
R rH
FST
FRRo
------------------
+
+ . - CW-03 MW-16D
' ■ ' a, CCR-103D r • <50 <50 '
+ ' `■ 1670
+ r r
+ _ J CCR-105D CW-02858 4 - - , . } �
r ` 831 - -
-
� 1
r
1981 C&D
t Q/
- �w
� CW-01
<50
MW-19D
<50
L I
4 + I . +
A
Bc-oz
' ' J
r1lr I
LMAYOPLA
APPROXIMATE FUTURE ASH BASIN WASTE BOUNDARY
f� `/ i t f• (SEE NOTES, THIS DRAWING)
I � ,
IN
I
i
vr^ ,
,
r
ULLINS LN � , I
N ,
7
G �
r +
11
400 200 0 400 800 1,200
GRAPHIC SCALE IN FEET
148 RIVER STREET, SUITE 220
synTerra GREENVILLE, SOUTH CAROLI A 29601
PHONE [phone]
I DRAWN BY: A. ROBINSON DATE:04/26/2019
ENERGY
PROJECT MANAGER: J. WYLIE
PROGRESS CHECKED BY: E. KINSEY
NORTH CAROLINA-VIRGINIA STATE LINE
(APPROXIMATE)
7
LEGEND
NOTES:
FIGURE 3-12
ISOCONCENTRATION MAP
GEOMEAN OF BORON IN TRANSITION ZONE FLOW ZONE
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC
ROXBORO, NORTH CAROLINA

t
RTh,
FSTFR
Rp
r------ CW-04
+ CCR-103BR
+ 2700 ■ a ~
MW-14BR +
<50 � ■' �
+ � w
CW-05 ■� r
ti rr
i
ti MW-13BR 1
<50
=4/ r
1
- P7)E.w.105BIRM]
yMW-02<509BR MW-16BR
3 <50
CCR-105BR
854
CW-06
<50
MW-08BR
<50
MW-104BRL CCR-10813R
■�
� CCR-104BR MW-04
<50 <50 -
I
„ •
MW-0913RL
<50
jp
■
ABMW-02BRL
<50 �
I <50
ABMW-02BR oPp <50
<50 gP��■
• l 1
BG-01
A
ri II
r
1
� I
i 1■� � yl ,s—
.�-
� , 1
` CW-02D
271.9
O` CCR-106BR
` 55
j MW-104BRM ` CCR-107BR
` �O <50 1060
" • MW-19BR
ABMW-04BR i <50
<50
MW-18BR
<50
+ I MW-10BR
<50
m
APPROXIMATE FUTUREASH BASIN WASTE BOUNDARY
(SEE NOTES, THIS DRAWING) -
.ti
■
ilaoo zoo o aoo eoo 1.200
I- GRAPHIC SCALE IN FEET
P 148 RIVER STREET, SUITE 220
synTerl'a
■ GREENVILLE, SOUTH CAROLINA 29601
DUKE PHONE[phone]
� www. n err r . m
ENERGY DRAWN BY: A. ROBINSON DATE: 04/25/2019
PROJECT MANAGER: J. WYLIE
+ PROGRESS CHECKED BY: E. KINSEY
NORTH CAROLINA-VIRGINIA STATE
7
LEGEND
0
0
NOTES:
a
FIGURE 3-13
ISOCONCENTRATION MAP
GEOMEAN OF BORON IN BEDROCK FLOW ZONE
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC
ROXBORO, NORTH CAROLINA

ABMW-04D
ABMW-03
5000
2000
f Boron
­v— Strontium
—E]-- Cobalt
4000
c
0
�
0
c 3000
c
1500
0
U
N
U
C
O
U
O
U
jBoron
2000
Strontium
Cobalt
0 1000
0
1000
U 10
U
5
0
0
^�
1/1/15 1/1/16 1/1/17
1/1/18
1/1/19
1/1/15
1/1/16
1/1/17
1/1/18 1/1/19
Time
Time
CW-02
CW-02D
1100
500
1000 -0-- Boron
f Boron
­�— Strontium
Strontium
J 900 --0-- Cobalt
400
—E]--- Cobalt
800
0 700
0
600
ca
300
500
400
U
�o
200
300
c
a�
200
o
c 100
c
100
0
U
U
5
5
0
0
1/1/10 1/1/11 1/1/12 1/1/13 1/1/14 1/1/15
1/1/16 1/1/17 1/1/18
1/1/19
1/1/10
1/1/11 1/1/12 1/1/13
1/1/14 1/1/15 1/1/16 1/1/17 1/1/18 1/1/19
Time
Time
Reference Boron Cobalt Manganese
LEGEND
Reporting Limits
148 RIVER STREET, SUITE 220
FIGURE 3-14
Criteria (pg/L) (pa/0 (pa/L)
Boron (u9/L
5o
GREENVILLE, SOUTH CAROLINA 29601
TIME —SERIES PLOTS
2L 700 N/A 50
L Cobalt (pg/)
0.1
PHONE:[phone]
IMAC N/A 1 N/A
Manganese (pg/L)
5
ASH BASIN (1 OF 2)
BTV (S) 50 1.02 253
Sulfate (mg/L.)
1
synTerra
www.synterracorp.com
2018 CAMA ANNUAL INTERIM
BTV (50 1 298
BTV (BR)
R) 50 1.19 544
MONITORING REPORT
Notes: N/A = Not Applicable BTV = Background Threshold Value S = Shallow D = Deep/Transition zone
`�� DUKE
DRAWN BY: H. GARRETT
PROJECT MANAGER: J. WYLIE
DATE: 4/3/2019
MAYO STEAM ELECTRIC PLANT
BR = Bedrock IMAC = Interim Maximum Allowable Concentration pg/L = micrograms per liter
'� ENERGY.
CHECKED BY: E.KINSEY
DUKE ENERGY PROGRESS, LLC
mg/L. = milligrams per liter
CAROLINAS
ROXBORO, NORTH CAROLINA

MW-16S
MW-16D
MW-16BR
700
200
600
f Boron
�— Strontium
140
f Boron
�— Strontium
Cobalt
150
J
J
J 120
—0-- Cobalt
500
f Boron
100
0
100
400
—0—obat
Cobalt
0
a)
300
v 50
80
�• N
• •T�• •T•
•
0
0
0 60
U
200
U 2
U
c
m
c
m
0 40
100
C:
C
20
U
U
U 5
10
0
0
0
1/1/15 1/1/16
1/1/17 1/1/18
1/1/19
1/1/15 1/1/16
1/1/17 1/1/18
1/1/19
1/1/15
1/1/16 1/1/17 1/1/18 1/1/19
Time
Time
Time
LEGEND
Reference Boron Cobalt Manganese
Reporting Limits
148 RIVER STREET, SUITE 220
FIGURE 3-15
Criteria (pg/L) (pa/0(pa/L)
BoronGREENVILLE,
0011
SOUTH CAROLINA 29601
TIME -SERIES PLOTS
2L 700 N/A 50
Cobalt (pg/L) 0.1
PHONE:[phone]
IMAC N/A 1 N/A
Manganese (pg/L) 5
ASH BASIN (2 OF 2)
BTV (S) 50 1.02 253
Sulfate (mg/L.) 1
synTerra
www.synterracorp.com
2018 CAMA ANNUAL INTERIM
BTV (D) 50 1 298
DUKE
DRAWN BY: H. GARRETT DATE:
4/3/2019
BTV (BR) 50 1.19 544
MONITORING REPORT
Notes: N/A = Not Applicable
BTV = Background Threshold Value S =
Shallow D = Deep/Transition ZoneENERGY
PROJECT MANAGER: J. WYLIE
MAYO STEAM ELECTRIC PLANT
BR = Bedrock IMAC = Interim Maximum Allowable Concentration
pg/L = micrograms per liter
x
CHECKED BY: E.KINSEY
DUKE ENERGY PROGRESS, LLC
mg/L. = milligrams per liter
CAROLINAS
ROXBORO, NORTH CAROLINA

2018 CAMA Annual Interim Monitoring Report April 30, 2019
Duke Energy Progress, LLC - Mayo Steam Electric Plant SynTerra
TABLES

TABLE 1-1
MONITORING WELL CONSTRUCTION INFORMATION
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Well ID
Date
Installed
Date
Abandoned
Monitoring Zone
Material
Diameter
(Inches)
Northing
(Ft-NAD 83)
Easting
(Ft-NAD 83)
Measuring Point
TOC Elevation
(Ft-NAVD 88)
Ground Surface
Elevation
(Ft-NAVD 88)
Boring
Depth 3
(Ft-BGS)
Surface Casing
Depth
(Ft-BGS)
Total Well
Depth
(Ft-BGS)
Measured Well
Depth
(Ft -TOC)
Screened
Interval
(Ft-BGS)
Top of Screen
Elevation
(Ft-NAVD 88)
Bottom of Screen
Elevation
(Ft-NAVD 88)
Ash Basin
ABM W-01
6/2/2015
NA
Ash
PVC
2.00
1012988.38
2029253.96
483.81
481.11
13.3
NA
13.3
15.65
2.8
13.3
478.66
468.16
ABM W-02
5/31/2015
NA
Ash
PVC
2.00
1012778.26
2030477.81
493.90
490.68
41.5
NA
39.2
42.48
34.0
39.2
456.62
451.42
ABMW-02BR
6/3/2015
NA
Bedrock
PVC
2.00
1012781.97
2030476.42
493.85
490.65
130.0
0-41.0
106.0
107.64
94.0
104.0
396.21
386.21
ABMW-02BRL
1/12/2016
NA
Bedrock
PVC
2.00
1012774.00
2030465.00
493.97
491.05
180.0
0-120.0
165.0
168.57
155.0
165.0
335.40
325.40
ABMW-03
5/20/2015
NA
Ash
PVC
2.00
1012714.21
2030856.72
500.17
497.34
40.5
NA
40.5
43.50
35.3
40.5
461.87
456.67
ABMW-03S
5/27/2015
NA
Saprolite
PVC
2.00
1012718.52
2030858.24
500.30
497.33
68.0
0-43.0
61.0
63.16
50.0
1 60.0
1 447.14
437.14
ABM W-04
5/31/2015
8/17/2018
Ash
PVC
2.00
1012345.36
2030478.85
491.44
488.76
60.0
NA
53.2
56.20
48.0
53.2
440.44
435.24
ABMW-04D
5/31/2015
NA
Transition Zone
PVC
2.00
1012350.06
2030467.97
491.50
488.68
64.5
0-54.5
64.5
65.75
55.8
61.0
430.95
425.75
ABMW-04BR
6/4/2015
NA
Bedrock
PVC
2.00
1012348.07
2030473.02
491.61
488.62
108.5
0-60.0
108.5
111.50
98.7
108.2
389.61
380.11
ABMW-04X
8/17/2018
NA
Ash
PVC
2.00
NM
NM
NM
NM
60.0
NA
54.0
60.00
49.0
54.0
NM
NM
AP-06
8/8/2018
NA
Ash
PVC
6.00
1013194.33
2030385.13
488.76
486.57
73.0
NA
65.2
65.20
45.0
55.0
433.56
423.56
CSA Wells
MW-03BR
2/10/2015
NA
Bedrock
PVC
2.00
1015654.79
2031277.75
438.24
435.53
77.0
NA
75.1
76.35
68.8
74.0
367.12
361.89
MW-05BR
1/30/2015
NA
Bedrock
PVC
2.00
1015146.30
2029179.66
511.40
508.74
67.0
NA
65.0
65.72
58.0
63.0
450.68
445.68
MW-06BR (piezometer)
4/13/2015
NA
Bedrock
PVC
2.00
1014756.09
2033040.31
463.99
461.70
100.0
NA
100.0
100.31
90.0
100.0
373.68
363.68
MW-07D
4/25/2015
6/12/2017
Transition Zone
PVC
2.00
1014307.45
2034169.17
453.94
451.17
32.5
NA
32.5
32.70
19.5
30.5
432.24
421.24
M W-07BR
4/24/2015
6/12/2017
Bedrock
PVC
2.00
1014311.86
2034175.46
453.50
451.21
77.5
NA
77.5
79.60
66.8
77.5
384.60
373.90
MW-08S (piezometer)
2/16/2015
NA
Saprolite
PVC
2.00
1014446.92
2034603.67
466.87
466.94
30.1
NA
30.1
30.20
25.0
30.0
441.67
436.67
MW-08D (piezometer)
2/16/2015
NA
Transition Zone
PVC
2.00
1014443.85
2034599.43
466.89
467.04
41.0
NA
41.0
38.30
33.3
38.5
433.79
428.59
MW-08BR
2/14/2015
NA
Bedrock
PVC
2.00
1014440.25
2034593.99
466.99
467.27
86.5
0-46.5
67.7
67.05
61.8
67.0
405.14
399.94
MW-09BR (piezometer)
4/11/2015
NA
Bedrock
PVC
2.00
1013360.32
2033864.48
495.39
492.85
66.0
NA
61.0
60.63
48.0
58.0
444.76
434.76
MW-09BRL
2/28/2017
NA
Bedrock
PVC
2.00
1013345.71
2033841.83
498.56
495.84
158.5
NA
70.3
73.44
60.5
70.3
435.00
425.12
M W-10BR
2/25/2015
NA
Bedrock
PVC
2.00
1011436.41
2032770.90
513.39
513.47
65.5
NA
65.5
57.60
48.0
58.0
465.79
455.79
MW-11BR(piezometer)
4/24/2015
NA
Bedrock
PVC
2.00
1010083.75
2027499.40
527.36
524.34
95.0
NA
95.0
98.80
84.3
94.4
438.66
428.56
MW-12S
4/29/2015
NA
Saprolite
PVC
2.00
1008653.91
2029202.47
587.38
587.48
56.0
NA
51.0
50.40
39.5
49.5
546.98
536.98
MW-12D
4/28/2015
NA
Transition Zone
PVC
2.00
1008654.13
2029191.43
588.02
588.17
97.0
NA
97.0
96.55
87.0
97.0
501.47
491.47
MW-13BR
4/15/2015
NA
Bedrock
PVC
2.00
1013587.37
2027633.00
528.83
526.67
107.0
NA
100.0
100.71
88.8
98.7
438.02
428.12
MW-14BR
2/5/2015
NA
Bedrock
PVC
2.00
1015432.97
2028964.70
520.75
517.76
46.4
NA
35.4
36.87
29.0
34.0
488.88
483.88
MW-15BR (piezometer)
5/12/2015
NA
Bedrock
PVC
2.00
1016021.83
2031813.20
460.92
460.94
78.5
NA
64.0
62.64
53.0
63.0
408.28
398.28
MW-16S
5/8/2015
NA
Alluvium
PVC
2.00
1015654.53
2032640.89
371.11
367.94
8.5
NA
8.5
10.59
4.9
7.6
363.22
360.52
MW-16D
5/8/2015
NA
Transition Zone
PVC
2.00
1 1015659.09
2032643.26
371.21
367.74
39.0
NA
39.0
41.44
28.7
38.9
339.97
329.77
MW-16BR
5/8/2015
NA
Bedrock
PVC
2.00
1015664.50
2032645.73
371.30
367.83
65.0
0-47.2
59.5
62.26
48.7
59.0
319.34
309.04
MW-17BR
1/10/2016
NA
Bedrock
PVC
2.00
1013955.00
2033766.00
490.55
487.51
120.0
NA
120.0
123.50
108.0
118.0
377.05
367.05
MW-18D
11/3/2016
NA
Transition Zone
PVC
2.00
1012472.09
2032396.93
516.71
514.46
49.5
NA
48.8
51.89
38.5
48.8
475.09
464.82
MW-18BR
11/8/2016
NA
Bedrock
PVC
2.00
1012468.45
2032399.87
516.78
514.45
129.5
59.50
111.0
113.69
96.0
111.0
418.09
403.09
MW-19D
11/4/2016
NA
Transition Zone
PVC
2.00
1012214.02
2032796.86
495.81
493.18
54.5
NA
54.1
57.03
43.5
54.1
449.41
438.78
MW-19BR
11/7/2016
NA
Bedrock
PVC
2.00
1012206.73
2032793.93
495.94
493.51
94.0
74.50
94.0
97.18
84.0
94.0
408.76
398.76
Previously Installed Wells
BG-1
10/15/2008
NA
Bedrock
PVC
2.00
1012000.52
2028480.40
540.11
537.04
UNK
NA
52.0
55.20
42.0
52.0
494.91
484.91
BG-2
9/28/2010
NA
Transition Zone
PVC
2.00
1010809.99
2028799.48
542.66
539.84
53.0
NA
53.0
48.40
25.4
44.9
513.76
494.26
CW-1
11/9/2010
NA
Transition Zone
PVC
2.00
1012696.54
2032714.46
489.88
486.96
25.5
NA
25.5
28.82
15.5
25.0
470.56
461.06
CW-11D
11/8/2010
NA
Bedrock
PVC
2.00
1012703.55
2032715.65
490.96
488.31
40.4
NA
40.4
43.65
30.1
39.9
457.11
447.31
CW-2
11/11/2010
NA
Transition Zone
PVC
2.00
1015043.98
2032238.71
389.00
386.56
18.0
NA
18.0
20.47
7.7
17.5
378.33
368.53
CW-2D
11/11/2010
NA
Bedrock
PVC
2.00
1015046.88
2032245.02
389.53
386.93
55.9
t NA
55.9
58.55
45.6
55.4
340.78
330.98
Page 1 of 2

TABLE 1-1
MONITORING WELL CONSTRUCTION INFORMATION
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Well ID
Date
Installed
Date
Abandoned
Monitoring Zone
Material
Diameter
(Inches)
Northing
(Ft-NAD 83)
Easting
(Ft-NAD 83)
Measuring Point
TOC Elevation
(Ft-NAVD 88)
Ground Surface
Elevation
(Ft-NAVD 88)
Boring
Depth 3
(Ft-BGS)
Surface Casing
Depth
(Ft-BGS)
Total Well
Depth
(Ft-BGS)
Measured Well
Depth
(Ft -TOC)
Screened
Interval
(Ft-BGS)
Top of Screen
Elevation
(Ft-NAVD 88)
Bottom of Screen
Elevation
(Ft-NAVD 88)
Previously Installed Wells (Continued)
CW-3
11/16/2010
NA
Transition Zone
PVC
2.00
1015647.59
2031278.02
437.68
435.27
32.3
NA
32.3
34.76
17.0
31.8
417.72
402.92
CW-4
11/12/2010
NA
Bedrock
PVC
2.00
1015911.44
2030436.27
451.31
448.76
40.3
NA
40.0
42.81
35.0
39.8
413.30
408.50
CW-5
11/15/2010
NA
Bedrock
PVC
2.00
1015162.23
2029182.29
509.60
507.21
43.0
NA
43.0
44.03
36.3
41.1
470.37
465.57
CW-6
11/11/2010
NA
Bedrock
PVC
2.00
1014743.82
2033046.08
462.83
NM
77.4
NA
77.4
80.56
72.1
76.9
387.07
382.27
MW-2
10/14/2008
NA
Bedrock
PVC
2.00
1015359.31
2030912.32
461.23
459.18
48.0
NA
48.0
50.12
38.0
48.0
421.11
411.11
MW-3
10/14/2008
NA
Alluvium
PVC
2.00
1 1014955.04
1 2032010.00
384.00
NM
18.0
NA
18.0
1 19.93
8.0
1 18.0
1 374.07
364.07
MW-4
10/15/2008
NA
Bedrock
PVC
2.00
1013846.48
2032346.28
522.77
519.46
55.0
NA
55.0
59.05
35.0
55.0
483.72
463.72
Previously Installed Piezometers
P1
c. 1983
NA
Earthen Dam
PVC
2.00
1015210.58
2030732.42
475.86
473.43
UNK
UNK
UNK
51.22
UNK
UNK
UNK
UNK
PIA
c. 1983
NA
Earthen Dam
PVC
2.00
1015207.52
2030735.62
475.00
473.38
UNK
UNK
UNK
36.40
UNK
UNK
UNK
UNK
P2
c. 1983
NA
Earthen Dam
PVC
2.00
1014965.67
2031226.56
458.65
455.77
UNK
UNK
UNK
49.66
UNK
UNK
UNK
UNK
P2A
c. 1983
NA
Earthen Dam
PVC
2.00
1014968.75
2031221.26
458.62
456.17
UNK
UNK
UNK
18.66
UNK
UNK
UNK
UNK
P3
c. 1983
NA
Earthen Dam
PVC
2.00
1014648.01
2031793.01
446.99
443.69
UNK
UNK
UNK
67.84
UNK
UNK
UNK
UNK
P3A
c. 1983
NA
Earthen Dam
PVC
2.00
1014650.72
2031787.93
445.69
443.39
UNK
UNK
UNK
51.34
UNK
UNK
UNK
UNK
P4
c. 1983
NA
Earthen Dam
PVC
2.00
1014521.83
2031950.40
454.57
452.59
UNK
UNK
UNK
64.15
UNK
UNK
UNK
UNK
P4A
c. 1983
NA
Earthen Dam
PVC
2.00
1014524.33
2031947.13
454.99
452.70
UNK
UNK
UNK
36.17
UNK
UNK
UNK
UNK
Previously Installed Production Wells
DEP-1 (piezometer)
c. 1980
NA
Bedrock
Steel
6.00
1008975.82
2031689.61
518.32
517.91
130.00
0-36
130.00
UNK
NA
NA
NA
NA
DEP-2 (piezometer)
c. 1980
NA
Bedrock
Steel
6.00
1009275.47
2029241.25
562.58
562.01
238.00
0-21
238.00
UNK
NA
NA
NA
NA
DEP-3 (piezometer)
c. 1980
NA
Bedrock
Steel
6.00
1009247.06
2029946.59
539.52
539.29
250.00
0-21
250.00
UNK
NA
NA
NA
NA
Staff Gauges/Sample Location
SW-CB1
3/3/2016
NA
Crutchfield Br
Fiberglass
0.25
1015087.00
2032239.00
375.88
NA
NA
NA
NA
NA
NA
NA
NA
NA
SW-CBT1
3/3/2016
NA
Trib to C'field Br
Fiberglass
0.25
1014867.00
2033298.00
407.22
NA
NA
NA
NA
NA
NA
NA
NA
NA
SW-CB2 (no staff gauge)
(no staff gauge)
NA
Crutchfield Br
NA
NA
pending
pending
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
SW-REF1
3/3/2016
NA
Background sw
Fiberglass
0.25
1008502.11
2031771.53
486.00
NA
NA
NA
NA
NA
NA
NA
NA
NA
Deep Bedrock Wells
MW-103BRM
10/18/2018
NA
Bedrock
PVC
2.00
1015454.71
2030518.47
490.46
487.59
240.0
175.00
240.0
NM
225.0
240.0
262.59
247.59
MW-103BRL
10/11/2018
NA
Bedrock
PVC
2.00
1015456.10
2030508.86
491.88
488.53
351.0
61, 106
351.0
NM
336.0
351.0
152.53
137.53
MW-104BRM
10/12/2018
NA
Bedrock
PVC
2.00
1015163.11
2031305.40
410.23
407.04
180.0
150.00
180.0
NM
165.0
180.0
242.04
227.04
MW-104BRL
10/10/2018
NA
Bedrock
PVC
2.00
1015167.41
2031318.21
410.08
407.03
250.0
21, 80
250.0
NM
235.0
250.0
172.03
157.03
MW-105BRM
10/11/2018
NA
Bedrock
PVC
2.00
1014912.57
2031777.45
391.14
392.43
125.0
100.00
125.0
NM
110.0
125.0
282.43
267.43
MW-105BRL
10/9/2018
NA
Bedrock
PVC
2.00
1014904.91
2031768.75
391.35
388.07
250.0
46, 87
250.0
NM
235.0
250.0
153.07
138.07
MW-107BRM
10/18/2018
NA
Bedrock
PVC
2.00
1014573.82
2032267.89
441.55
438.30
192.0
125.00
192.0
NM
177.0
192.0
261.30
246.30
MW-107BRL
10/11/2018
NA
Bedrock
PVC
2.00
1014570.06
2032273.45
443.32
439.82
302.0
46, 67
302.0
NM
287.0
302.0
152.82
137.82
Notes:
** Estimated until ground surface elevation is resurveyed
i - Well depths initially measured during well installation and updated as new wells are installed.
2 - "Boring Depth" is the total depth of soil boring; "Total Well Depth" is the depth to the bottom of the filter pack
3 - Values measured during well installation
BGS - Below ground surface NM - Not measured
Ft -Feet PVC- Polyvinyl chloride
NA - Not applicable RM - Needs to be remeasured
NAD 83 - North American Datum 1983 TOC - Top of Casing
NAVD 88 - North American Vertical Datum 1988 UNK - Data not known
Prepared by: RKD Checked By: JAW
Page 2 of 2

TABLE 2-1
2018 CAMA WATER ELEVATIONS
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO NC
Well ID
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Screened
Interval
(Ft-BGS)
Monitoring Zone
Groundwater Elevation
(Ft - NAVD-88)
01/15-01/18/18
Groundwater Elevation
(Ft - NAVD-88)
04/02-04/03/18
Groundwater Elevation
(Ft - NAVD-88)
07/12-07/18/18
Groundwater Elevation
(Ft - NAVD-88)
11/05-11/06/18
ABMW-1
480.75
480.47
478.54
481.3
2.8
13.3
Ash
ABMW-2
482.36
483.05
482.93
483.66
34.0
39.2
Ash
ABMW-2BR
481.75
482.93
482.83
483.02
94.0
104.0
Bedrock
ABMW-2BRL
481.44
482.51
482.26
482.73
155.0
165.0
Bedrock
ABMW-3
482.52
483.12
482.96
483.54
35.3
40.5
Ash
ABMW-3S
482.48
483.13
482.9
483.52
50.0
60.0
Saprolite
ABMW-4
483.56
484.99
-
484.94
48.0
53.2
Ash
ABMW-4BR
483.76
485.13
484.9
485.91
98.7
108.2
Bedrock
ABMW-4D
483.49
484.98
484.74
485.67
55.8
61.0
Transition Zone
BG-1
507.93
508.91
510.25
513.23
42.0
52.0
Bedrock
BG-2
509.74
509.66
510.16
510.8
25.4
44.9
Transition Zone
CCR-101D-BG
-
-
511.24
513.62
11.20
16.20
Transition Zone
CCR-101S-BG
-
-
500.3
501.28
29.16
34.16
Surficial (Saprolite)
CCR-102BR-BG
-
-
499.26
501.18
63.15
73.15
Bedrock
CCR-103BR
-
-
472.47
472.96
67.48
77.48
Bedrock
CCR-103D
-
-
470.94
471.76
46.55
56.55
Transition Zone
CCR-103S
-
-
469.69
470.84
23.19
33.19
Surficial (Saprolite)
CCR-104BR
-
-
401.72
408.58
40.2
50.2
Bedrock
CCR-104S
-
407.08
404.93
6.75
11.75
Surficial (Saprolite/
Alluvium
CCR-105BR
-
-
379.18
381.75
37.36
47.36
Bedrock
CCR-105D
-
-
380.50
383.05
21.93
26.93
Transition Zone
CCR-105S
-
-
378.30
383.15
11.12
16.12
Surficial (Saprolite)
CCR-106BR
-
-
375.56
377.6
34.16
44.16
Transition Zone
CCR-107BR
-
-
434.03
438.55
25.18
35.18
Bedrock
CCR-108BR
-
-
471.12
473.35
48.53
58.53
Bedrock
CCR-109BR
-
-
-
396.36
53.65
68.65
Bedrock
CW-1
470.37
471.17
471.09
472.27
15.5
25
Transition Zone
CW-1D
470.36
470.96
470.95
472.11
30.1
39.9
Bedrock
CW-2
374.95
376.48
374.54
376.82
7.7
17.5
Transition Zone
CW-2D
373.07
374.10
373.08
373.67
45.6
55.4
Bedrock
CW-3
417.54
419.19
419.17
419.41
17
31.8
Transition Zone
CW-4
427.19
428.16
428.05
428.78
35
39.8
Bedrock
Page 1 of 3

TABLE 2-1
2018 CAMA WATER ELEVATIONS
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO NC
Well ID
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Screened
Interval
(Ft-BGS)
Monitoring Zone
Groundwater Elevation
(Ft - NAVD-88)
01/15-01/18/18
Groundwater Elevation
(Ft - NAVD-88)
04/02-04/03/18
Groundwater Elevation
(Ft - NAVD-88)
07/12-07/18/18
Groundwater Elevation
(Ft - NAVD-88)
11/05-11/06/18
CW-5
493.62
498.42
499.09
501.66
36.3
41.1
Bedrock
CW-6
446.40
447.38
448.65
449.89
72.1
76.9
Bedrock
DEP-1
-
502.82
503.82
504.84
NA
NA
Bedrock
DEP-2
-
544.73
544.84
545.63
NA
NA
Bedrock
DEP-3
-
518.27
515.92
518.52
NA
NA
Bedrock
MW-10BR
498.31
498.24
498.29
501.16
48.0
58.0
Bedrock
MW-11BR
-
490.06
-
490.54
84.3
94.4
Bedrock
MW-12D
553.31
553.74
555.17
555.52
87.0
97.0
Transition Zone
MW-12S
552.94
553.39
555.03
555.04
39.5
49.5
Saprolite
MW-13BR
498
498.46
498.5
499.34
88.8
98.7
Bedrock
MW-14BR
499.28
501.9
501.55
502.7
29.0
34.0
Bedrock
MW-15BR
-
401.32
-
402.16
53.0
63.0
Bedrock
MW-16BR
364.23
365.41
364.08
366.78
48.7
59.0
Bedrock
MW-16D
364.62
365.62
364.32
367.13
28.7
38.9
Transition Zone
MW-16S
365.21
365.51
364.46
367.27
4.9
7.6
Alluvium
MW-17BR
-
457.27
-
460.76
108.0
118.0
Bedrock
MW-18BR
492.02
495.64
496.25
504.35
96.0
111.0
Bedrock
MW-18D
489.59
492.02
492.93
505.06
38.5
48.8
Transition Zone
MW-19BR
483.57
485.97
485.73
487.86
84.0
94.0
Bedrock
MW-19D
484.77
487.34
487.29
488.76
43.5
54.1
Transition Zone
MW-2
431.81
433.29
433.81
434.53
38.0
48.0
Bedrock
MW-3
377.4
377.53
-
378.15
8.0
18.0
Alluvium
MW-3BR
418.62
419.69
419.64
420.11
68.8
74.0
Bedrock
MW-4
486.95
489.67
491.23
492.26
35.0
55.0
Bedrock
MW-5BR
493.89
497.39
498.54
501.92
58.0
63.0
Bedrock
MW-6BR
-
447.89
449.19
449.61
90.0
100.0
Bedrock
MW-8BR
430.25
430.82
431.52
431.89
61.8
67.0
Bedrock
MW-8D
-
431.29
431.54
438.71
33.3
38.5
Transition Zone
MW-8S
-
437.01
437.01
437.02
25.0
30.0
Saprolite
MW-9BR
-
463.96
463.51
466.54
48.0
58.0
Bedrock
MW-9BRL
461.16
465.25
464.49
467.32
60.5
70.3
Bedrock
PZ-1
-
443.01
437.8
442.74
UNK
UNK
Earthen Dam
PZ-1A
-
438.21
441.38
437.52
UNK
UNK
Earthen Dam
Page 2 of 3

TABLE 2-1
2018 CAMA WATER ELEVATIONS
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO NC
Well ID
Quarter 1
Quarter 2
Quarter 3
Quarter 4
Screened
Interval
(Ft-BGS)
Monitoring Zone
Groundwater Elevation
(Ft - NAVD-88)
01/15-01/18/18
Groundwater Elevation
(Ft - NAVD-88)
04/02-04/03/18
Groundwater Elevation
(Ft - NAVD-88)
07/12-07/18/18
Groundwater Elevation
(Ft - NAVD-88)
11/05-11/06/18
PZ-2
-
412.92
412.86
434.35
UNK
UNK
Earthen Dam
PZ-2A
-
-
-
442.16
UNK
UNK
Earthen Dam
PZ-3
-
394.36
394.05
395.23
UNK
UNK
Earthen Dam
PZ-32D
-
-
-
-
-
-
-
PZ-32S
-
-
-
-
-
-
-
PZ-3A
-
396.32
393.9
399.91
UNK
UNK
Earthen Dam
PZ-4
-
414.77
414.28
414.98
UNK
UNK
Earthen Dam
PZ-4A
-
-
-
-
UNK
UNK
Earthen Dam
Notes:
0 - water level identified as anamolous likely due to field transcription error
Not measured/available
* - Abandoned sampling location
** - Survey information incomplete/not available
Artesian conditions present
Z - Installed in 2018, not sampled
BGS - below ground surface
BTP - Water Level below top of pump
Dry - Well was dry at time of Water Level check
Ft - feet
NAVD 88 - North American Vertical Datum of 1988.
UNK - Unknown
Prepared by: HEG Checked by: GTC
Page 3 of 3

TABLE 3-1
HORIZONTAL HYDRAULIC GRADIENTS AND FLOW VELOCITIES
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Saprolite
Source Area
Upgradient
Groundwater
Level hl (ft)1
Downgradient
Groundwater
Level h2 (ft)1
K
(ft/day)2
Ah
(ft)
Al
(ft)
n 2
a
v
(ft/day)
v
(ft/yr)
Gradient
(Ah/AI)
Ash Basin
480
380
3.000
100.00
375
0.2
4.000
1460.00
0.27
Ash Basin
1 480
1 380
1 3.000
100.00
350
1 0.2
4.286
1564.291
0.29
Ash Basin
1 470
1 380
1 3.000
1 90.00
1 450
1 0.2
3.000
1 1095.001
0.20
Saprolite
Geometric Mean 1 3.72 11357.361 0.25
Average 1 3.76 11373.10 0.25
Deep Flow Zone
Upgradient
Downgradient
Source Area
Groundwater
Groundwater
K
Ah
Al
n 2
vs
vs
Gradient
Level hl (ft)1
Level h2 (ft)1
(ft/day)2
(ft)
(ft)
a
(ft/day)
(ft/yr)
(Ah/AI)
Ash Basin
480
380
1.000
100.00
350
0.2
1.429
521.43
0.29
Ash Basin
480
1 380
1 1.000
100.00
975
1 0.2
0.513
187.18
1 0.10
Transition Zone
Geometric Mean 0.86 312.41 0.17
Average 0.97 354.30 0.19
Bedrock Flow Zone
Upgradient
Downgradient
Source Area
Groundwater
Groundwater
K
Ah
Al
n 2
vs
vs
Gradient
Level hl (ft)1
Level h2 (ft)1
(ft/day)2
(ft)
(ft)
a
(ft/day)
(ft/yr)
(Ah/AI)
Ash Basin
480
380
0.030
100.00
375
0.05
0.160
58.40
0.27
Ash Basin
480
380
0.030
100.00
1088
0.05
0.055
20.14
0.09
Bedrock
Geometric Mean 0.09 34.29 0.16
Average 0.11 39.27 0.18
Prepared by: GTC Checked by:ENK
Notes:
1 - Groundwater level shown corresponds to upgradient groundwater contour on Figures 3-1 through 3-3
2 - Groundwater level shown corresponds to downgradient groundwater contour on Figures 3-1 through 3-3
3 - Values taken from Preliminary Updated Groundwater Flow and Transport Modeling Report for Allen Steam Station, Belmont, NC, November 2018 (SynTerra)
4 - The length of a flow path between an upgradient and downgradient groundwater contor within the same flow zone
dh/dl - horizontal hydraulic gradient (ft/ft)
ft - feet
h - water level height in feet
K - horizontal hydraulic conductivity
I - horizontal distance between wells
ne - effective porosity
vs - horizontal seepage velocity
Page 1 of 1

TABLE 3-2
VERTICAL HYDRAULIC GRADIENTS
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Well ID
Monitoring
Zone
Reference
Cross -Section
Total Well
Depth
(Ft-BGS)
Water Level
Elevation
4Q-2018
Vertical Gradient
(dh/dl)
and Flow Direction
Upgradient of Ash Basin
CW-5
Bedrock
A -A'
43
501.66
1.31E-02
Upward
MW-05BR
Deep Bedrock
65
501.92
MW-12S
Saprolite
B-B'
51
555.04
1.05E-02
Upward
MW-12D
Transition
97
555.52
Within Ash Basin
ABMW-02
Saprolite
B-B'
39.2
483.66
1.02E-02
Downward
AMBW-02BR
Bedrock
106
483.02
ABMW-02BR
Bedrock
B-B'
106
483.02
4.77E-03
Downward
ABMW-02BRL
Deep Bedrock
165
482.73
ABMW-03
Ash Pore Water
B-B'
40.5
483.54
1.17E-03
Downward
ABMW-03S
Saprolite
61
483.52
ABMW-04
Ash Pore Water
NA
53.2
484.94
1.83E-02
Upward
ABMW-04BR
Bedrock
108.5
485.91
ABMW-04
Ash Pore Water
NA
53.2
484.94
7.69E-02
Upward
ABMW-04D
Transition
64.5
485.67
Downgradient of Ash Basin
MW-16S
Saprolite
B-B'
8.5
367.27
1.03E-02
Downward
MW-16BR
Bedrock
59.5
366.78
CW-2
Transition
B-B'
18
376.82
8.39E-02
Downward
CW-2D
Bedrock
40.4
373.67
CW-3
Transition
NA
32.3
419.41
1.53E-02
Upward
MW-03BR
Bedrock
75.1
420.11
Sidegradient of Ash Basin
MW-18D
Transition
A -A'
48.8
505.06
1.20E-02
Downward
MW-18BR
Bedrock
111
504.35
M W-19D
Transition
A -A'
54.1
488.76
2.23E-02
Downward
MW-19BR
Bedrock
94
487.86
CW-1
Transition
NA
25.5
472.27
1.18E-02
Downward
CW-ID
Bedrock
40.4
472.11
M W-08S
Saprolite
NA
30.1
437.02
2.12E-01
Upward
MW-08BR
Bedrock
67.7
431.89
Notes:
' - "Boring Depth" is the total depth of soil boring; "Total Well Depth" is the depth to the bottom of the filter pack.
z - Values measured during well installation
BGS - Below ground surface
Ft - Feet
NAVD 88 - North American Vertical Datum 1988
Vertical gradient calculations based on June 19-20, 2017 water level data collected within 24 hours
Prepared by: GTC Checked by: ENK
Page 1 of 1

TABLE 3-3
2018 COMPREHENSIVE GROUNDWATER QUALITY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
FIELD PARAMETERS
WATER QUALITY PARAMETERS
SELECTED 40CFR257 APPENDIX III CONSTITUENTS plus Sr
INORGANIC PARAMETERS (TOTAL CONCENTRATION)
Analytical Parameter
pH
Water
Level
Temp
Spec
Cond
DO
ORP
Eh
Turbidity
Alkalinity
Bi-
carbonate
Alkalinity
Sulfide
Total
Organic
Carbon
Total
Suspended
Solids
Boron
Calcium
Chloride
Strontium
Sulfate
Total
Dissolved
Solids
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
(VI)
Chromium
Cobalt
Reporting Units
S.U.
ft
Deg C
umhos/cm
mg/L
mV
mV
NTUs
mg/L
mg/L
mg/L
mg/L
mg/L
ug/L
mg/L
mg/L
ug/L
mg/L
mg/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
15A NCAC 02L Standard
6.5-8.5
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
700
NE
250
NE
250
500
NE
1*
10
700
4*
2
10
10
1*
Provisional Background Threshold Values (Surficial Unit)
4.9-6.5
NE
NE
NE
NE
NE
NE
NE
13
13
0.1
2
NE
50
2.89
3.3
25
1.6
85
566
1
1
19
1
1
0.088
3.23
1.02
Provisional Background Threshold Values (Transition Zone Unit)
5.7-6.5
NE
NE
NE
NE
NE
NE
NE
302
302
0.1
1.8
NE
50
59.2
33.3
391
7.5
430
490
1
1
78.3
1
1
1.26
6
1
Provisional Background Threshold Values (Bedrock Unit)
5.0-7.3
NE
NE
NE
NE
NE
NE
NE
223
223
0.1
1.01
NE
50
73.3
43
418
18
340
536
1
1
97
1
1
0.4
7
1.19
Sample ID
Well Screen
Location
Sample
Collection Date
Analytical Results
ABMW-01
Ash Pore Water
O1/16/2018
7.8
3.06
13
555
0.16
-145
60
8.3
281
281
<0.1
3.851
<5
5900
49.9
15
1850
29
300
156
12
172
430
<1
<1
<0.025
<1
2.86
ABMW-01
Ash Pore Water
04/03/2018
7.9
3.20
16
562
0.19
-217
-12
5.9
264
264
<0.1
3.3 S1
<5
5400
49.8
14
1680
25
300
132
5.06
282
476
<1
<1
0.039
0.4j
3.04
ABMW-01
Ash Pore Water
07/19/2018
7.4
4.92
21
981
0.20
-57
148
5.3
453
453
<0.1
3
16
4080
99.5
16
3640
11
500
90
10.3
368
1010
<1
<1
<0.025
0.371j
11.1
ABMW-01
Ash Pore Water
11/08/2018
7.9
2.66
14
551
0.61
-178
27
9.7
286
286
<0.1 Ml,RI
3.2 S1
6
5090
48.6
15
1890
23
340
160
7.67
373
546
<1
<1
<0.025
0.393j
1.78
ABMW-02
Ash Pore Water
01/16/2018
8.9
11.54
14
629
0.27
-136
69
1.0
284
252
<0.1
7.8SI
<5
9140
12
13
815
35
370
96
<1
936
54
<1
<1
<0.025
<1
<1
ABMW-02
Ash Pore Water
04/03/2018
9.3
10.89
16
690
0.24
-75
130
1.7
287
239
<0.1
7.3
<5
7980
11.5
14
728
39
390
72
<1
935
48
<1
<1
<0.025
<1
<1
ABMW-02
Ash Pore Water
07/19/2018
9.4
10.92
34
733
0.26
51
256
1.1
326
274
0.23
7.3
<5
8270
23.1
14
921
36
410
77
<1
896
64
<1
<1
<0.025
<1
<1
ABMW-02
Ash Pore Water
11/07/2018
9.0
10.29
23
685
0.45
65
270
0.7
270
212
0.27
7.6
<5
8600
14.2
SS
784
35
340
78
1.07
920
53
<1
<1
0.027
<1
<1
ABMW-02BR
Bedrock
01/16/2018
7.5
12.10
14
572
0.44
-133
72
2.3
274
274
0.1
1.3SI
<5
<50
76.1
26
1080
11
340
48
<1
3.26
105
<1
<1
0.025
<1
<1
ABMW-02BR
Bedrock
04/03/2018
7.5
11.01
SS
594
0.40
-60
145
1.3
283
283
<0.1
1.1 sl
<5
<50
80.8
26
1140
12
320
27
<1
2.98
109
<1
<1
<0.025
<1
<1
ABMW-02BR
Bedrock
07/19/2018
7.5
11.14
29
607
0.30
19
224
1.4
269
269
<0.1
0.75
<5
<50
76.9
27
1090
12
360
17
<1
3
104
<1
<1
<0.025 P4,RO
<1
<1
ABMW-02BR
Bedrock
11/07/2018
7.3
10.61
23
618
0.53
82
287
0.4
245
245
<0.1
0.704 SI
<5
19.895j
86.3
28
1180
13
320
11
<1
3.11
110
<1
<1
<0.025
<1
<1
ABMW-02BRL
Bedrock
01/16/2018
7.5
12.53
15
492
0.48
-159
46
0.9
236
236
0.14
1.5 S1
5
<50
67.3
21
2250
<0.1
280
16
<1
2.6
72
<1
<1
<0.025
<1
<1
ABMW-02BRL
Bedrock
04/03/2018
7.6
11.54
16
507
0.57
6
211
1.3
256
256
<0.1
1.3
6
<50
69.9
20
2210
<0.1
280
13
<1
2.68
75
<1
<1
<0.025
<1
<1
ABMW-02BRL
Bedrock
07/19/2018
7.6
11.76
28
519
0.45
24
229
1.1
244
244
<0.1
0.955
<5
<50
65.3
20
2130
0.26
310
15
0.373j
2.86
72
<1
<1
<0.025
<1
<1
ABMW-02BRL
Bedrock
11/07/2018
7.4
11.13
21
528
0.55
63
268
1.0
221
221
<0.1
0.97 SI
<5
<50
72.1
22
2280
0.38
270
SS
<1
2.23
72
<1
<1
<0.025
<1
<1
ABMW-03
Ash Pore Water
01/16/2018
6.8
17.65
17
573
0.22
-122
83
1.6
138
138
<0.1 Ml
2.8 S1
15
2010
60.4
66
1600
36
320
61
<1
247
242
<1
<1
0.027
<1
<1
ABMW-03
Ash Pore Water
04/03/2018
6.9
17.13
21
581
0.22
-34
171
2.3
137
137
<0.1
2.5 SI
12
1940
62.7 M4
67
1480
38
310
34
<1
93.8
215
<1
<1
<0.025
<1
<1
ABMW-03
Ash Pore Water
07/18/2018
6.5
17.15
27
591
0.43
264
469
2.4
171
171
<0.1
2.3 S1
9
1940
63.6
64
1590
23
320
30
<1
67.2
242
<1
<1
<0.025
0.383j
<1
ABMW-03
Ash Pore Water
11/08/2018
6.9
16.56
18
594
0.44
80
285
0.7
115
115
<0.1
2.4 SI
14
1960
59.3
70
1370
41
310
33
<1
288
203
<1
<1
<0.025
0.359j
<1
ABMW-03S
Saprolite
01/16/2018
5.2
17.82
14
109
0.31
126
331
8.8
30.7
30.7
<0.1
1.2 S1
<5
1280
3.35
12
75
0.39
100
82
<1
1.54
25
<1
<1
0.04 P4,RO
<1
1.88
ABMW-03S
Saprolite
04/03/2018
5.2
17.08
21
116
0.44
115
320
8.4
30.6
30.6
<0.1
0.953 SI
<5
1300
3.39
12
77
0.42 SI
88
27
<1
0.701j
26
0.502j
<1
<0.025
1.08
1.62
ABMW-03S
Saprolite
07/18/2018
5.0
17.32
26
105
0.21
511
716
9.2
32.1
32.1
<0.1
0.59 S1
<5
1340
3.18
12
77
0.39
94
22
<1
0.732j
28
0.452j
<1
<0.025
<1
1.59
ABMW-03S
Saprolite
11/08/2018
5.2
16.76
18
111
0.46
376
581
8.3
29
29
<0.1
0.643 SI
<5
1340
3.32
13
80
0.35
97
26
<1
0.862j
30
0.473j
<1
<0.025
<1
1.45
ABMW-04
Ash Pore Water
01/16/2018
7.2
7.88
14
852
0.29
-178
27
2.4
477
477
0.11
2.8 S1
18
6130
117
11
3060
44
540
27
<1
346
587
<1
<1
<0.025
<1
1.82
ABMW-04
Ash Pore Water
04/03/2018
7.4
6.52
17
893
0.30
-132
73
2.3
502
502
0.12
2.7 SI
20
5900
123
11
3050
49
530
21
<1
382
623
<1
<1
<0.025
<1
2.41
ABMW-04BR
Bedrock
01/16/2018
7.3
7.85
9
519
0.61
-173
32
1.0
236
236
0.11
1.1 S1
<5
<50
80.1
5.1
2060
49
320
21
<1
1.8
108
<1
<1
<0.025 P4,RO
<1
<1
ABMW-04BR
Bedrock
04/03/2018
7.8
6.53
16
540
0.37
-144
61
4.7
234
234
0.12
0.848 SI
<5
20.206j
84.4
5.3
2020
48
300
26
<1
1.91
113
<1
<1
<0.025
<1
<1
ABMW-04BR
Bedrock
07/18/2018
7.4
6.50
24
537
0.70
211
416
0.6
234
234
<0.1
0.47SI
<5
<50
80.1
5.4
2020
46
310
15
<1
2.02
109
<1
<1
<0.025
0.347j
<1
ABMW-04BR
Bedrock
11/08/2018
7.8
5.67
17
526
0.47
66
271
0.8
225
225
0.34
0.788 SI
<5
38.274j
76.7
5.7
1920
37
320
19
<1
1.97
118
<1
<1
<0.025
0.521j
<1
ABMW-04D
Transition Zone
01/16/2018
6.4
8.01
13
1052
0.40
-90
115
9.9
556
556
<0.1
7.5SI
100
3450
111
14
1840
1.7
550
386
<1
24.9
890
<1
<1
<0.025 P4,110
1.16
5.85
ABMW-04D
Transition Zone
04/03/2018
6.3
6.60
18
1072
0.37
-54
151
7.6
513
513
<0.1
7.4
82
3050
111
14
1590
0.55 sl
520
184
<1
23
904
<1
<1
<O.025 P4,R0
0.95j
6.11
ABMW-04D
Transition Zone
07/18/2018
6.1
6.74
24
1081
0.32
292
497
0.9
522
522
<0.1
7
71
3430
114
14
1760
1.6
530
159
<1
23.1
907
<1
<1
<0.025 P4,110
0.759j
5.34
ABMW-04D
Transition Zone
11/08/2018
6.3
5.90
19
1059
0.40
174
379
6.7
481
481
<0.1
7
70
3040
111
13
1580
2.3
500
115
<1
21.4
901
<1
<1
<0.025
0.795j
6.3
ABMW-04X
Ash Pore Water
11/08/2018
7.0
6.50
20
709
0.20
-48
157
5.5
311
311
<0.1
5.6 S1
17
5290
91.2
12
2310
43
430
88
<1
63
443
<1
<1
<0.025
0.692j
0.444j
BG-01
Bedrock
O1/16/2018
5.7
32.18
13
147
2.42
187
392
2.5
54.1
54.1
<0.1
0.992 SI
<5
<50
12
10
174
0.28
110
22
<1
<1
83
<1
<1
0.34
<1
<1
BG-01 IMP
Bedrock
04/04/2018
5.5
31.10
16
149
1.58
335
540
0.8
58.5
58.5
<0.1
0.86 S1
<5
<50
12.7
10
177
0.3
130
230
<1
<1
94
<1
<1
0.36
0.703j
<1
BG-01 IMP
Bedrock
07/16/2018
5.5
28.89
20
146
1.67
494
699
3.8
56.8
56.8
<0.1
0.585 SI
<5
<50
12.5
10
170
0.24
98
Ill
<1
<1
88
<1
<1
0.42
0.687j
<1
BG-01
Bedrock
11/06/2018
5.6
26.84
17
145
2.18
338
543
1.4
51.2
51.2
<0.1
0.494 S1
<5
<50
12.6
8.9
176
0.25
110
553
<1
<1
86
<1
<1
0.47
0.839j
<1
BG-02
Transition Zone
O1/15/2018
6.5
32.92
15
579
0.17
17
222
1.9
218
218
<0.1
1.5 sl
<5
<50
50.4 B2
39
292
5.6
270
62
<1
<1
41
<1
<1
<0.025
<1
<1
BG-02 IMP
Transition Zone
04/03/2018
6.4
32.90
18
565
0.21
262
467
1.9
222
222
<0.1
1.7SI
<5
<50
50.9
39
291
5.5
300
49
<1
<1
42
<1
<1
<0.025
4.33
<1
BG-02 IMP
Transition Zone
07/17/2018
6.3
32.28
20
527
0.21
368
573
1.1
206
206
<0.1
1.3SI
<5
<50
49.5
42
277
5.5
340
30
<1
<1
38
<1
<1
<0.025 MI
<1
<1
BG-02
Transition Zone
11/06/2018
6.3
31.85
17
579
0.12
240
445
1.4
203
203
<0.1
1.4SI
<5
<50
52.6
39
299
5.2
290
14
<1
<1
42
<1
<1
<0.025
<1
<1
CW-OS
Transition Zone
O1/15/2018
6.0
19.51
13
148
4.79
127
332
3.0
36.7
36.7
<0.1
0.539 SI
<5
<50
9.32 B2
17
59
8.4
130
SOS sl
<1
<1
<5
<1
<1
0.12
<1
<1
CW-01 IMP
Transition Zone
04/03/2018
5.9
18.05
1S
142
5.65
327
532
2.0
37
37
<0.1
0.67 S1
7
<50
9.34
16
64
8.2
120
349
<1
<1
3.289j
<1
<1
0.13
1.14
<1
CW-OS IMP
Transition Zone
07/16/2018
5.6
18.80
30
160
4.06
434
639
0.5
38.4
38.4
<0.1 RI
0.39 SI
<5
<50
8.79
16
65
9.1
110
25
<1
<1
<5
<1
<1
0.11
<1
<1
CW-Ol
Transition Zone
11/06/2018
5.7
17.61
20
161
3.88
289
494
1.0
35.9
35.9
<0.1
0.55 Sl
<5
<50
8.61
16
61
9.4
110
24
<1
<1
<5
<1
<1
0.15
0.425 j
<1
CW-OID
Bedrock
O1/15/2018
7.3
20.60
11
380
0.50
21
226
3.0
193
193
<0.1
0.371 SI
<5
<50
57.8 B2
9.8
211
3.1
220
88
<1
<1
<5
<1
<1
<0.025
<1
<1
CW-01D IMP
Bedrock
04/03/2018
7.0
19.95
20
354
2.14
315
520
2.3
185
185
<0.1
0.583 SI
<5
<50
48.2
9.4
172
3
200
7
<1
<1
1.845j
<1
<1
0.056
0.432j
<1
CW-01D IMP
Bedrock
07/17/2018
6.7
20.00
25
334
1.89
406
611
8.6
176
176
<0.1
0.264 SI
<5
<50
47.2
9.4
180
2.8
220
18
<1
<1
1.742j
<1
<1
0.12
0.805j
<1
CW-01D
Bedrock
11/06/2018
6.7
18.85
20
387
0.54
313
518
3.2
164
164
<0.1
0.311 S1
<5
<50
47.2
8.3
177
2.4
ISO
25
<1
<1
2.008j
<1
<1
0.063
0.646j
<1
CW-02
Transition Zone
O1/17/2018
5.3
14.05
11
311
2.15
220
425
0.3
6.2
6.2
<0.1
1.3
<5
1060
19.7 B2
61
297
44
170
16
<1
<1
143
<1
<1
0.12
<1
<1
CW-02 IMP
Transition Zone
04/03/2018
5.3
12.60
11
236
4.52
327
532
0.3
<5
<5
<0.1
1.4SI
<5
799
16.1
45
210
42
150
19
<1
<1
Ill
<1
<1
0.099
<1
<1
CW-02 IMP
Transition Zone
07/16/2018
5.0
14.60
22
259
0.97
501
706
0.2
7.5
7.5
<0.1
0.811 SI
<5
970
16.2
43
221
42
140
12
<1
<1
109
<1
<1
0.095
<1
<1
CW-02
Transition Zone
11/07/2018
5.2
1 12.34
17
190
1 0.81
1 174
1 3791
5.1
1 6.27
1 6.27
1 <0.1
I 1.3SI
1 <5
661
1 11.1
1 26
1 159
1 33
100
126
<1
<1
78
<1
<1
0.1
<1
<1
Page 1 of 9

TABLE 3-3
2018 COMPREHENSIVE GROUNDWATER QUALITY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Analytical Parameter
INORGANIC PARAMETERS (TOTAL CONCENTRATION)
INORGANIC PARAMETERS (DISSOLVED CONCENTRATION WITH FILTER SIZE)
Copper
ug/L
Iron
ug/L
Lead
ug/L
Lithium
ug/L
Magnesium
mg/L
Manganese
ug/L
Mercury
ug/L
Molybdenum
ug/L
Nickel
ug/L
Nitrate +
Nitrite
mg-N/L
Potassium
mg/L
Selenium
ug/L
Sodium
mg/L
Thallium
ug/L
Vanadium
ug/L
Zinc
ug/L
Aluminum
(0.45u)
ug/L
Antimony
(0.45u)
ug/L
Arsenic
(0.45u)
ug/L
Barium
(0.45u)
ug/L
Beryllium
(0.45u)
ug/L
Boron
(0.45u)
ug/L
Cadmium
(0.45u)
ug/L
Chromium
(0.45u)
ug/L
Cobalt
(0.45u)
ug/L
Copper
(0.45u)
ug/L
Iron
(0.45u)
ug/L
Reporting Units
15A NCAC 02L Standard
1000
300
15
NE
NE
50
1
NE
100
NE
NE
20
NE
0.2*
0.3*
1000
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Provisional Background Threshold Values (Surficial Unit)
1.9
385
1
NE
0.753
253
0.2
3.15
3.03
0.798
3.78
1
5.49
0.2
0.974
227
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Provisional Background Threshold Values (Transition Zone Unit)
5
1319
1
NE
13.5
298
0.2
1
5
1 0.295
1 3.61
1
53.3
0.2
5.88
12
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Provisional Background Threshold Values (Bedrock Unit)
5
2550
1
NE
13.1
544
0.05
13.1
5
1 1.03
1 6.56
1
72.6
0.2
S.s2
37.9
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Sample ID
Well Screen
Location
Sample
Collection Date
Analytical Results
ABMW-01
Ash Pore Water
01/16/2018
<1
1260
<1
1050
22.6
566
<0.05
268
3.2
<0.02
20.7
<1
17.5 BI
0.328
85.4
<5
154
12.5
125
402
<1
5530
<1
<1
2.67
<1
825 SI
ABMW-01
Ash Pore Water
04/03/2018
0.489j
1950
<1
1010
26.3
601
<0.05
267
2.4
<0.02
22.3
<1
17.4
0.17j
32.7
<5
112
5.28
251
438
<1
5450
<1
<1
2.77
<1
1260
ABMW-01
Ash Pore Water
07/19/2018
0.959j
5600
<1
804
45.7
1870
<0.05
167
11.8
<0.01
24.7
<1
19.1
0.55
52.5
7
73
9.52
363
932
<1
4480
<1
<1
9.89
<1
4300
ABMW-01
Ash Pore Water
11/08/2018
0.728j
1940
<1
930
31.5
627
<0.05
274
1.55
<0.01
24.1
<1
17.9
<0.2
27.4
6
156
6.98
376
540
<1
5400
<1
<1
1.58
<1
1430
ABMW-02
Ash Pore Water
01/16/2018
<1
23 S1
<1
1130
16.8
16
<0.05
1340
<1
<0.02
65.2 M4
<1
60.2 B1
<0.2
0.618
<5
73
<1
987
71
<1
8450
<1
<1
<1
<1
35 S1
ABMW-02
Ash Pore Water
04/03/2018
<1
15
<1
1060
17.1
21
<0.05
1360
0.422j
<0.02
78.7
<1
67.3
<0.2
0.569
<5
67
<1
992
98
<1
8670
<1
<1
<1
<1
69
ABMW-02
Ash Pore Water
07/19/2018
<1
33
<1
1100
17.2
152
<0.05
1350
2.96
<0.01
72.7
<1
61.7
<0.2
0.852
<5
68
<1
943
92
<1
8360
<1
<1
<1
<1
41
ABMW-02
Ash Pore Water
11/07/2018
<1
12
<1
1120
18.7
47
<0.05
1330
<1
<0.05
74.5
<1
60.7
<0.2
0.655
<5
72
0.501j
1020
68
<1
8440
<1
<1
<1
<1
19
ABMW-02BR
Bedrock
01/16/2018
<1
1330
<1
<5
12.5
236
<0.05
18.4
<1
<0.02
5.74 B3
<1
24.2 B1
<0.2
<0.3
<5
<5
<1
1.63
105
<1
<50
<1
<1
<1
<1
1210 S1
ABMW-02BR
Bedrock
04/03/2018
<1
1270
<1
2.508 j
13.4
235
<0.05
17.3
<1
<0.02
6
<1
23.9
<0.2
0.19 j
<5
3.406 j
<1
2.46
110
<1
<50
<1
<1
<1
<1
1100
ABMW-02BR
Bedrock
07/19/2018
<1
1250
<1
4.082j
12.9
228
<0.05
19
<1
<0.01
5.67
<1
22.5
0.083j
0.335
3.287j
4.8671
<1
2.2
115
<1
<50
<1
<1
<1
<1
1110
ABMW-02BR
Bedrock
11/07/2018
<1
1280
<1
<5
14.4
227
0.018j
20.1
<1
<0.01
5.83
<1
24.1
<0.2
0.161j
<5
3.462j
<1
2
117
<1
18.662j
<1
<1
<1
<1
1040
ABMW-02BRL
Bedrock
01/16/2018
<1
1950
<1
<5
10.4
358
<0.05
2.62
<1
<0.02
5.95 B3
<1
17.4 B1
<0.2
<0.3
<5
7
<1
2.03
73
<1
<50
<1
<1
<1
<1
1660 S1
ABMW-02BRL
Bedrock
04/03/2018
<1
18s0
<1
2.99j
11
357
<0.05
2.38
<1
<0.02
6.15
<1
17.6
<0.2
0.189j
<5
7
<1
2.02
74
<1
<50
<1
<1
<1
<1
1670
ABMW-02BRL
Bedrock
07/19/2018
<1
1860
<1
4.1911
10.4
339
<0.05
2.62
<1
<0.01
5.8
<1
16.6
<0.2
0.375
2.526 j
8
<1
2.28
76
<1
<50
<1
<1
<1
<1
1750
ABMW-02BRL
Bedrock
11/07/2018
<1
1630
<1
1.828 j
11.2
328
0.023 j
2.16
<1
<0.01
6.09
<1
17.5
<0.2
<0.3
<5
6
<1
1.7
74
<1
<50
<1
<1
<1
<1
1520
ABMW-03
Ash Pore Water
01/16/2018
<1
13300
<1
234
12.7
763
<0.05
37.6
<1
0.04
13.2 B3
<1
12.5 BI
<0.2
0.584
<5
21
<1
243
229
<1
1870
<1
<1
<1
<1
11000
ABMW-03
Ash Pore Water
04/03/2018
<1
6060
<1
218
13.5
616
<0.05
34.7
<1
<0.02
13.4
<1
15.1
<0.2
0.397
<5
13
<1
143
208
<1
1920
<1
<1
<1
<1
5400
ABMW-03
Ash Pore Water
07/18/2018
<1
6170
<1
215
14.1
785
<0.05
19.2
<1
0.00731
13.7
<1
13.7 B2
<0.2
0.34551
2.173j,B2
11
<1
106
231
<1
1920
<1
<1
<1
<1
4740
ABMW-03
Ash Pore Water
11/08/2018
<1
8160
<1
238
13.1
504
<0.05
38.3
<1
0.012
12.7
<1
15.8
0.1j
0.335
2.029j
18
<1
280
193
<1
2000
<1
<1
<1
<1
6220
ABMW-03S
Saprolite
01/16/2018
<1
2700
<1
<5
0.765
303
<0.05
<1
<1
<0.02
0.938 B3
<1
15.8 B1
<0.2
0.711
<5
10
<1
<1
23
<1
1280
<1
<1
1.86
<1
1740 S1
ABMW-03S
Saprolite
04/03/2018
0.338j
1120
<1
<5
0.816
304
<0.05
0.108j
0.627j
<0.02
0.936
<1
15.9
<0.2
0.371
2.738j
10
<1
<1
24
<1
1270
<1
<1
1.59
<1
307
ABMW-03S
Saprolite
07/18/2018
<1
1100
<1
3.7891
0.832
294
<0.05
<1
<1
<0.01
0.941
<1
15.7 B2
<0.2
0.39 S1
7 B2
11
<1
<1
27
0.385j
1310
<1
<1
1.56
<1
167
ABMW-03S
Saprolite
11/08/2018
<1
1340
<1
1.876 j
0.798
285
<0.05
0.099 j
<1
<0.01
0.926
<1
15.8
<0.2
0.642 S1
4 j
39 S1
<1
0.466 j
29
0.439 j
1350
<1
<1
1.46
<1
653
ABMW-04
Ash Pore Water
01/16/2018
<1
6980
<1
546
31.5 R1
2150
<0.05
281
<1
0.03
27.3 B3
<1
15.5 BI
<0.2
4.06
<5
17
<1
375
612
<1
6040
<1
<1
2.11
<1
6860
ABMW-04
Ash Pore Water
04/03/2018
<1
8150
<1
530
32.7
2190
<0.05
320
1.05
<0.02
27.5
<1
14.5
0.105j
3.94
<5
15
<1
387
654
<1
6150
<1
<1
2.18
<1
7420
ABMW-04BR
Bedrock
01/16/2018
<1
790 S1
<1
<5
5.61
448
<0.05
5.55
<1
<0.02
5.92 B3
<1
20.7 B1
<0.2
<0.3
<5
11
<1
1.32
127
<1
<50
<1
<1
<1
<1
733 SI
ABMW-04BR
Bedrock
04/03/2018
0.564j
918
<1
2.571j
5.98
474
<0.05
5.36
<1
<0.02
5.86
<1
20.7
<0.2
0.218j
<5
13
<1
1.43
125
<1
33.916j
<1
<1
<1
<1
591
ABMW-04BR
Bedrock
07/18/2018
0.393j
790
<1
3.2551
5.96
483
<0.05
5.5
0.362j
<0.01
5.84
<1
20.2
<0.2
0.349 S1
<5
11
<1
1.27
132
<1
34.188j
<1
<1
<1
<1
646
ABMW-04BR
Bedrock
11/08/2018
<1
589
<1
3.015j
5.58
435
<0.05
22.3
<1
<0.01
6.18
<1
27
<0.2
0.189j
<5
9
<1
1.39
126
<1
28.812j
<1
<1
<1
<1
904
ABMW-04D
Transition Zone
01/16/2018
<1
56900
<1
24
34.1
6160
<0.05
15.7
1.52
0.071
15 B3
<1
16.3 BI
<0.2
8.58
<5
69
<1
25.6
900
<1
3750
<1
<1
5.14
<1
53500
ABMW-04D
Transition Zone
04/03/2018
<1
57900
<1
12
34.2
6190
<0.05
3.26
1.46
0.046
13.1
<1
15.9
<0.2
10.3
<5
65
<1
23.2
871
<1
3290
<1
0.709j
5.15
<1
53800
ABMW-04D
Transition Zone
07/18/2018
<1
54500
<1
31
37.5
6360
<0.05
17.1
0.893j
0.027
16.3
<1
17 B2
0.106 j,S1
8.52
6 B2
65
<1
22
880
<1
3400
<1
0.627j
4.82
<1
50600
ABMW-04D
Transition Zone
11/08/2018
<1
53600
<1
17
33.2
6s90
<0.05
8.07
0.947j
0.037
13.7
<1
16.1
<0.2
9.75
<5
41
<1
21.2
886
<1
3410
<1
0.779j
5.43
<1
51100
ABMW-04X
Ash Pore Water
11/08/2018
<1
3570
<1
505
23.3
1390
<0.05
158
<1
0.0069j
18.7
0.508j
16.3
<0.2
2.81
<5
16
<1
80.9
465
<1
5610
<1
0.483j
0.3571
<1
4520
BG-01
Bedrock
01/16/2018
<1
18 S1
<1
<5
3.16
<5
<0.05
<1
1.2
0.83
1.33 B3
<1
11.7 BI
<0.2
3.84
<5
<5
<1
<1
85
<1
<50
<1
<1
<1
<1
<10
BG-01 IMP
Bedrock
04/04/2018
0.899 j
126 SI
<1
3.629 j
3.35
9
<0.05
<1
1.32
0.92
1.34
<1
11.8
0.081 j
4.42
3.977 j
2.866 j
<1
<1
88
<1
<50
<1
0.384 j
<1
<1
<10
BG-01 IMP
Bedrock
07/16/2018
<1
91
<1
3.143j
3.35
8
0.02j
<1
1.36
0.869
1.33
<1
11.2
<0.2
3.94
4.785j
2.527j
<1
<1
87
<1
<50
<1
0.464j
<1
<1
<10
BG-01
Bedrock
11/06/2018
0.899j
286
<1
2.1751
3.3
14
0.029j
<1
1.04
0.886
1.31
<1
11.7
<0.2
4.58
5
2.2531
<1
<1
86
<1
<50
<1
0.604j
<1
<1
<10
BG-02
Transition Zone
01/15/2018
<1
180
<1
6
10.5
86
<0.05
<1
<1
0.026 SI
3.36
<1
45.6 B3
<0.2
4.44
<5
<5
<1
<1
41
<1
<50
<1
<1
<1
<1
97
BG-02 IMP
Transition Zone
04/03/2018
0.41j
187
<1
4.6671
10.5
82
<0.05
0.8511
3.98
0.028
3.26
<1
43.8
0.082j
4.26
<5
1.6991
<1
<1
40
<1
<50
<1
3.58
<1
<1
126
BG-02 IMP
Transition Zone
07/17/2018
<1
94
<1
3.739j
9.85
62
<0.05
0.629j
0.508j
0.033
3.31
<1
42.7
<0.2
4.72
1.975j
<5
<1
<1
37
<1
<50
<1
<1
<1
<1
52
BG-02
Transition Zone
11/06/2018
0.617j
122
<1
2.9551
10.9
105
0.02j
0.6351
0.355j
0.024
3.32
<1
45
<0.2
4.61
<5
<5
<1
<1
39
<1
<50
<1
<1
<1
<1
82
CW-01
Transition Zone
01/15/2018
1.56
130
<1
<5
3.48
11
<0.05
<1
<1
1.5
1.24
<1
15.9 B3
<0.2
0.884
12
22
<1
<1
<5
<1
<50
<1
<1
<1
1.36
<10
CW-01 IMP
Transition Zone
04/03/2018
2.51
279
<1
2.733j
3.35
18
<0.05
0.4581
0.975j
1.6
1.16
<1
15.7
<0.2
1.03
11
2.665j
<1
<1
1.966j
<1
<50
<1
<1
<1
0.7191
<10
CW-01 IMP
Transition Zone
07/16/2018
1.32
23
<1
<5
3.71
4.043j
<0.05
0.321j
0.649j
1.5
1.01
<1
15.8
<0.2
O.s02 S1
9
315
<1
<1
4.816j
<1
<50
<1
0.806j
<1
1.72
424
CW-01
Transition Zone
11/06/2018
2.41
22
<1
1.803j
3.48
3.707j
0.018j
0.3571
0.376j
1.5
1.03
<1
16
<0.2
0.561
11
3.079j
<1
<1
<5
<1
<50
<1
0.335j
<1
1.27
<10
CW-OSD
Bedrock
01/15/2018
<1
69
<1
<5
8.97
65
<0.05
24.8
<1
<0.02
2.73
<1
13.4 B3
<0.2
1.28
<5
<5
<1
<1
<5
<1
<50
<1
<1
<1
<1
<10
CW-01D IMP
Bedrock
04/03/2018
<1
7.226j
<1
<5
9.29
10
<0.05
20.6
<1
0.31
2.18
<1
13.3
<0.2
1.14
1.9731
2.216j
<1
<1
1.748j
<1
<50
<1
<1
<1
0.3821
<10
CW-01D IMP
Bedrock
07/17/2018
0.36j
21
<1
<5
9.17
8
<0.05
21.8
<1
0.276
2.12
<1
13.1
<0.2
1.27
2.447j
2.257j
<1
<1
1.729j
<1
<50
<1
0.478j
<1
<1
14
CW-011)
Bedrock
11/06/2018
0.809j
26
<1
<5
9.38
17
<0.05
22.2
<1
0.227
2.16
<1
13.3
<0.2
1.37
2.7931
3.104j
<1
<1
1.819j
<1
<50
<1
<1
<1
0.4941
<10
CW-02
Transition Zone
01/17/2018
<1
<10
<1
<5
9.48
92
<0.05
<1
1.29
0.055
2.08
<1
17.8 B3
<0.2
<0.3
9
10
<1
<1
140
<1
966
<1
<1
<1
<1
<10
CW-02 IMP
Transition Zone
04/03/2018
<1
4.441j
<1
<5
8.21
58
<0.05
<1
0.846j
<0.02
1.83
<1
16.1
<0.2
j 0.18j
3.636j
11
<1
<1
110
<1
792
<1
<1
<1
<1
<10
CW-02 IMP
Transition Zone
07/16/2018
<1
3.724j
<1
<5
7.55
313
<0.05
<1
1.87
0.02
1.87
<1
17
<0.2
0.222 j,S1
3.404j
9
<1
<1
106
<1
959
<1
<1
<1
<1
7.195j
CW-02
Transition Zone
11/07/2018
0.588j
92
<1
1 <5
5.37
107
1 0.018j
<1
0.997j
0.017
1.74
<1
13
<0.2
0.441
6
9
<1
<1
76
<1
649
<1
<1
<1
0.5191
11
Page 2 of 9

TABLE 3-3
2018 COMPREHENSIVE GROUNDWATER QUALITY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Analytical Parameter
INORGANIC PARAMETERS (DISSOLVED CONCENTRATION WITH FILTER SIZE)
RADIONUCLIDES
OTHER PARAMETERS
Lead
(0.45u)
ug/L
Lithium
(0.45u)
ug/L
Manganese
(0.45u)
ug/L
Mercury
(0.45u)
ug/L
Molybdenum
(0.45u)
ug/L
Nickel
(0.45u)
ug/L
Phosphorus
(0.45u)
mg/L
Selenium
(0.45u)
ug/L
Silver
(0.45u)
ug/L
Strontium
(0.45u)
ug/L
Thallium
(0.45u)
ug/L
Vanadium
(0.45u)
ug/L
Zinc
(0.45u)
ug/L
Radium-226
pCi/L
Radium-228
pCi/L
Total Radium
pCi/L
Uranium-238
ug/mL
Total Uranium
ug/mL
Carbonate
Alkalinity
mg/L
Fluoride
mg/L
Phosphorus
mg/L
Reporting Units
15A NCAC 02L Standard
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
5^
NE
0.03^
NE
2
NE
Provisional Background Threshold Values (Surficial Unit)
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
4
NE
0.000367
5
NE
NE
Provisional Background Threshold Values (Transition Zone Unit)
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
9
NE
0.001
5
NE
NE
Provisional Background Threshold Values (Bedrock Unit)
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
7.6
NE
0.00203
5
NE
NE
Sample ID
Well Screen
Location
Sample
Collection Date
Analytical Results
ABMW-01
Ash Pore Water
01/16/2018
<1
1010
507
<0.05
277
2.87
<0.05
<1
NA
1780
0.284
88.2
<5
<1
<1
<RL
NA
0.105
<5
0.19
0.087 SI
ABMW-01
Ash Pore Water
04/03/2018
<1
1030
539
<0.05
301
2.2
0.077
<1
NA
1600
0.194j
12.2
<5
0.897
0.256 U
1.153
NA
0.0885
<5
0.17
0.097
ABMW-01
Ash Pore Water
07/19/2018
<1
866
1710
<0.05
192
9.77
0.076
<1
NA
3340
0.469
33.6
5
0.434
0.288 U
0.722
NA
0.0762
<5
0.14
0.14
ABMW-01
Ash Pore Water
11/08/2018
<1
981
613
<0.05
284
0.829j
0.12
<1
NA
1950
<0.2
12.3
1.817j
0.123 U
0.372 U
0.495
0.0733
0.0733
<5
0.21
0.19
ABMW-02
Ash Pore Water
01/16/2018
<1
1030
159
<0.05
1410
<1
0.064
<1
NA
967
<0.2
0.621
<5
NA
NA
NA
NA
NA
31.5
1.2
0.051 M1,S1
ABMW-02
Ash Pore Water
04/03/2018
<1
1060
329
<0.05
1490
<1
0.084
<1
NA
1300
0.117j
0.727
<5
NA
NA
NA
NA
NA
48
1.2
0.06
ABMW-02
Ash Pore Water
07/19/2018
<1
1050
298
<0.05
1420
0.346j
0.12
<1
NA
1230
<0.2
0.666
<5
NA
NA
NA
NA
NA
51.6
1.1
0.1
ABMW-02
Ash Pore Water
11/07/2018
<1
1060
154
<0.05
1500
<1
0.077
<1
NA
938
<0.2
0.698
<5
NA
NA
NA
NA
NA
57.9
0.88
0.064
ABMW-02BR
Bedrock
01/16/2018
<1
<5
227
<0.05
17.6
<1
<0.05
<1
NA
1100
<0.2
<0.3
36
NA
NA
NA
NA
NA
<5
1.2
<0.05
ABMW-02BR
Bedrock
04/03/2018
<1
2.962j
220
<0.05
15.9
<1
<0.05
<1
NA
1110
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
1.2
<0.05
ABMW-02BR
Bedrock
07/19/2018
<1
4.4851
221
<0.05
16.6
<1
<0.05
<1
NA
1160
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
1.1
<0.05
ABMW-02BR
Bedrock
11/07/2018
<1
1.803j
205
<0.05
17.1
<1
<0.05
<1
NA
1160
<0.2
0.255j
<5
NA
NA
NA
NA
NA
<5
1.1
<0.05
ABMW-02BRL
Bedrock
01/16/2018
<1
<5
339
<0.05
2.05
<1
<0.05
<1
NA
2310
<0.2
<0.3
12
NA
NA
NA
NA
NA
<5
0.93
<0.05
ABMW-02BRL
Bedrock
04/03/2018
<1
2.964j
353
<0.05
2.08
<1
<0.05
<1
NA
2210
<0.2
0.104j
<5
NA
NA
NA
NA
NA
<5
0.89
<0.05
ABMW-02BRL
Bedrock
07/19/2018
<1
4.1831
313
<0.05
1.62
<1
<0.05
<1
NA
2370
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
0.84
<0.05
ABMW-02BRL
Bedrock
11/07/2018
<1
1.739j
337
0.018j
1.77
<1
<0.05
<1
NA
2330
<0.2
0.227j
<5
NA
NA
NA
NA
NA
<5
0.77
<0.05
ABMW-03
Ash Pore Water
01/16/2018
<1
219
673
<0.05
38.2
<1
<0.05
<1
NA
1510
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
0.47
<0.05
ABMW-03
Ash Pore Water
04/03/2018
<1
223
569
<0.05
38
<1
<0.05
<1
NA
1440
<0.2
0.16j
<5
NA
NA
NA
NA
NA
<5
0.42
<0.05
ABMW-03
Ash Pore Water
07/18/2018
<1
222
718
<0.05
19.9
<1
<0.05
<1
NA
1610
<0.2
0.185 j,B3
1.968j
NA
NA
NA
NA
NA
<5
0.43
<0.05
ABMW-03
Ash Pore Water
11/08/2018
<1
237
458
<0.05
44.6
<1
<0.05
<1
NA
1310
<0.2
0.199j
<5
NA
NA
NA
NA
NA
<5
0.43
<0.05
ABMW-035
Saprolite
01/16/2018
<1
<5
300
<0.05
<1
<1
<0.05
<1
NA
75
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
<0.1
<0.05
ABMW-03S
Saprolite
04/03/2018
<1
<5
294
<0.05
<1
<1
<0.05
<1
NA
74
<0.2
<0.3
3.283 j
NA
NA
NA
NA
NA
<5
<0.1
0.052
ABMW-03S
Saprolite
07/18/2018
<1
<5
278
<0.05
0.134j
<1
<0.05
<1
NA
72
<0.2
0.182 j, B3
4.082j
NA
NA
NA
NA
NA
<5
<0.1
<0.05
ABMW-03S
Saprolite
11/08/2018
<1
<5
269
0.018 j
<1
<1
<0.05
<1
NA
75
<0.2
<0.3
5
NA
NA
NA
NA
NA
<5
0.0547 j
<0.05
ABMW-04
Ash Pore Water
01/16/2018
<1
516
2160
<0.05
289
<1
<0.05
<1
NA
3140
<0.2
4.09
<5
0.817
0.773
1.59
NA
0.000872
<5
0.27
<0.05
ABMW-04
Ash Pore Water
04/03/2018
<1
540
2270
<0.05
310
0.997j
0.055
<1
NA
3220
<0.2
4
<5
1.12
0.431 U
1.551
NA
0.000677
<5
0.27
0.057
ABMW-04BR
Bedrock
01/16/2018
<1
<5
399
<0.05
19.1
<1
<0.05
<1
NA
2020
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
1.1
<0.05
ABMW-04BR
Bedrock
04/03/2018
<1
3.946j
381
<0.05
21
<1
<0.05
<1
NA
1940
<0.2
0.163j
<5
NA
NA
NA
NA
NA
<5
1
<0.05
ABMW-04BR
Bedrock
07/18/2018
<1
2.4451
423
<0.05
17.2
<1
<0.05
<1
NA
2060
<0.2
0.232 j,B3
1.891j
NA
NA
NA
NA
NA
<5
1.1
<0.05
ABMW-04BR
Bedrock
11/08/2018
<1
1.804j
419
0.019j
12.2
<1
<0.05
<1
NA
2020
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
1.1
<0.05
ABMW-04D
Transition Zone
01/16/2018
<1
33
5640
<0.05
21
<1
<0.05
<1
NA
2010
<0.2
7.76
<5
NA
NA
NA
NA
NA
<5
0.14
<0.05
ABMW-04D
Transition Zone
04/03/2018
<1
22
5750
<0.05
9.43
0.861j
<0.05
<1
NA
1710
<0.2
8.62
<5
NA
NA
NA
NA
NA
<5
0.2745j
<0.05
ABMW-04D
Transition Zone
07/18/2018
<1
29
6050
<0.05
16.3
0.7991
<0.05
<1
NA
1850
<0.2
7.34 B3
2.537j
NA
NA
NA
NA
NA
<5
0.14
<0.05
ABMW-04D
Transition Zone
11/08/2018
<1
27
6040
<0.05
15.8
0.585j
<0.05
<1
NA
1820
<0.2
8.88
1.903j
NA
NA
NA
NA
NA
<5
0.11
<0.05
ABMW-04X
Ash Pore Water
11/08/2018
<1
517
1520
<0.05
169
<1
0.058
0.401j
NA
2480
<0.2
2.36
<5
1.1
0.394 U
1.494
0.000272
0.000272
<5
0.33
0.056
BG-01
Bedrock
01/16/2018
<1
<5
<5
<0.05
<1
<1
0.17
<1
NA
175
<0.2
3.79
<5
2.97
<1
2.97
NA
0.00147
<5
0.12
0.1771
BG-01 IMP
Bedrock
04/04/2018
<1
<5
5
<0.05
0.1j
1.26
0.2
<1
NA
174
0.225
3.7
4.779j
4.13
0.215 U
4.345
NA
0.0001231
<5
0.0923j
0.17
BG-01 IMP
Bedrock
07/16/2018
<1
3.787j
4.808j
<0.05
<1
1.14
0.16
<1
NA
168
<0.2
3.2
6
2.52
0.186 U
2.706
NA
<0.0002
<5
0.0658j
0.17
BG-01
Bedrock
11/06/2018
<1
1.756j
4.451j
<0.05
<1
1.02
0.18
<1
NA
177
<0.2
3.82
4.545j
1.69
0.0533 U
1.7433
<0.0002
<0.0002
<5
0.0793j
0.19
BG-02
Transition Zone
01/15/2018
<1
6
70
<0.05
<1
<1
0.15
<1
NA
294
<0.2 B2
4.23
<5
0.706
<1
0.706
NA
0.000839
<5
0.34
0.16
BG-02 IMP
Transition Zone
04/03/2018
<1
4.688j
69
<0.05
0.798j
5.04
0.16
<1
NA
280
0.104j
4.04
<5
2.75
0.172 U
2.922
NA
0.000718
<5
0.31
0.16
BG-02 IMP
Transition Zone
07/17/2018
<1
3.674j
57
<0.05
0.507j
0.533j
0.14
<1
NA
273
<0.2
4.39
<5
2.29
0.0147 U
2.3047
NA
0.00061
<5
0.28
0.14
BG-02
Transition Zone
11/06/2018
<1
3.288j
82
<0.05
0.628j
<1
0.15
<1
NA
290
<0.2
4.21
1.707j
1.56
0.145 U
1.705
0.000639
0.000639
<5
0.26
0.15
CW-01
Transition Zone
01/15/2018
<1
<5
<5
<0.05
<1
<1
0.17
<1
NA
59
<0.2 B2
0.744
13
NA
NA
NA
NA
NA
<5
0.13
0.18
CW-01 IMP
Transition Zone
04/03/2018
<1
3.05 j
3.103 j
<0.05
0.486 j
0.699 j
0.16
<1
NA
65
<0.2
0.528
9
NA
NA
NA
NA
NA
<5
0.0808 j
0.18
CW-01 IMP
Transition Zone
07/16/2018
<1
<5
14
<0.05
0.296j
0.907j
0.17 MI
<1
NA
67
<0.2
1.03
13
NA
NA
NA
NA
NA
<5
0.0817j
0.21
CW-01
Transition Zone
11/06/2018
<1
2.047j
2.91
<0.05
0.316j
<1
0.2
<1
NA
66
<0.2
0.547
11
NA
NA
NA
NA
NA
<5
0.0964j
0.19
CW-OSD
Bedrock
01/15/2018
<1
<5
15
<0.05
27.2
<1
0.13
<1
NA
198
<0.2 B2
1.25
<5
NA
NA
NA
NA
NA
<5
0.17
0.12
CW-01D IMP
Bedrock
04/03/2018
<1
<5
4.192 j
<0.05
21.8
0.54 j
0.16
0.363 j
NA
169
<0.2
1.27
2.485 j
NA
NA
NA
NA
NA
<5
0.13
0.17
CW-01D IMP
Bedrock
07/17/2018
<1
<5
<5
<0.05
20.4
0.347j
0.14
0.608j
NA
178
0.169j
1.23
1.744j
NA
NA
NA
NA
NA
<5
0.15
0.15
CW-011)
Bedrock
11/06/2018
<1
<5
<5
<0.05
21.9
<1
0.19
<1
NA
174
<0.2
1.24
3.281 j
NA
NA
NA
NA
NA
<5
0.13
0.18
CW-02
Transition Zone
01/17/2018
<1
<5
83
<0.05
<1
1.29
<0.05
<1
NA
286
<0.2
<0.3
7
1.92
<1
1.92
NA
<0.0002
<5
<0.1
<0.05
CW-02 IMP
Transition Zone
04/03/2018
<1
<5
56
<0.05
<1
0.936j
<0.05
<1
NA
209
0.104j
0.103j
4.08j
4.63
0.0451 U
4.6751
NA
<0.0002
<5
<0.1
<0.05
CW-02 IMP
Transition Zone
07/16/2018
<1
<5
305
<0.05
<1
1.74
<0.05
<1
NA
217
<0.2
0.117j
4.039j
0 U
0.308 U
0.308
NA
<0.0002
<5
<0.1
<0.05
CW-02
Transition Zone
11/07/2018
<1
<5
305
<0.05
<1
0.934j
<0.05
<1
NA
153
<0.2
0.289j
7
2.68
0.265 U
2.945
<0.0002
<0.0002
<5
<0.1
<0.05
Page 3 of 9

TABLE 3-3
2018 COMPREHENSIVE GROUNDWATER QUALITY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
FIELD PARAMETERS
WATER QUALITY PARAMETERS
SELECTED 40CFR257 APPENDIX III CONSTITUENTS plus Sr
INORGANIC PARAMETERS (TOTAL CONCENTRATION)
Analytical Parameter
pH
Water
Level
Temp
Spec
Cond
DO
ORP
Eh
Turbidity
Alkalinity
carBi-
bonate
Alkalinity
Sulfide
Total
Organic
Carbon
Total
Suspended
Solids
Boron
Calcium
Chloride
Strontium
Sulfate
Total
Dissolved
Solids
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
(VI)
Chromium
Cobalt
Reporting Units
S.U.
ft
Deg C
umhos/cm
mg/L
mV
mV
NTUs
mg/L
mg/L
mg/L
mg/L
mg/L
ug/L
mg/L
mg/L
ug/L
mg/L
mg/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
15A NCAC 02L Standard
6.5-8.5
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
700
NE
250
NE
250
Soo
NE
1*
10
700
4*
2
10
10
1*
Provisional Background Threshold Values (Surficial Unit)
4.9-6.5
NE
NE
NE
NE
NE
NE
NE
13
13
0.1
2
NE
So
2.89
3.3
25
1.6
85
566
1
1
19
1
1
0.088
3.23
1.02
Provisional Background Threshold Values (Transition Zone Unit)
5.7-6.5
NE
NE
NE
NE
NE
NE
NE
302
302
0.1
1.8
NE
50
59.2
33.3
391
7.5
430
490
1
1
78.3
1
1
1.26
6
1
Provisional Background Threshold Values (Bedrock Unit)
5.0-7.3
NE
NE
NE
NE
NE
NE
NE
223
223
0.1
1.01
NE
50
73.3
43
418
18
340
536
1
1
97
1
1
0.4
7
1.19
Sample ID
Well Screen
Location
Sample
Collection Date
Analytical Results
CW-02D
Bedrock
01/17/2018
7.0
16.46
6
547
0.42
25
230
2.6
147
147
<0.1 M1
1.1
<5
242
77.8 B2
34
369
71
320
33
<1
<1
22
<1
<1
0.033
<1
<1
CW-02D IMP
Bedrock
04/03/2018
7.1
15.45
14
515
0.96
211
416
0.8
100
100
<0.1
0.991 SI
<5
407
48.3
42
321
57
260
533
0.537j
0.561j
40
<1
<1
1.7
22.7
0.65j
CW-02D IMP
Bedrock
07/16/2018
7.0
16.56
22
633
0.80
339
544
9.1
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
CW-02D IMP
Bedrock
07/17/2018
6.8
30.30
23
565
3.72
404
609
9.5
162
162
<0.1
0.735 SI
9
263
80.4
36
409
80
360
180
0.553j
0.405j
26
<1
<1
0.45
5.28
<1
CW-02D
Bedrock
11/07/2018
7.2
15.73
16
745
0.33
18
223
8.5
158
158
<0.1
0.532 S1
<5
211
83.5
35
386
76
310
55
0.3991
0.427j
19
<1
<1
0.25
1.07
<1
CW-03
Transition Zone
O1/22/2018
6.7
20.14
16
581
1.96
43
248
9.9
140
140
<0.1
2.1 SI
17
<50
62.3
94
309
17
350
414
<1
<1
15
<1
<1
0.055
<1
<1
CW-03 IMP
Transition Zone
04/04/2018
6.6
18.40
17
598
2.76
53
258
3.6
147
147
<0.1
2.1 S1
9
<50
61.6
91
312
17
350
110
<1
<1
19
<1
<1
0.052
0.484 j
<1
CW-03 IMP
Transition Zone
07/17/2018
6.2
18.60
22
543
1.33
410
615
3.5
137
137
<0.1
1.8 SI
10
<50
59.2
88
304
16
370
220
<1
<1
17
<1
<1
0.053
0.583 j
<1
CW-03
Transition Zone
11/08/2018
6.2
18.28
16
580
0.96
63
268
7.6
129
129
<0.1
1.9 SI
<5
<50
58.5
88
300
17
350
161
<1
<1
14
<1
<1
0.065 S1
0.381 j
<1
CW-04
Bedrock
O1/17/2018
6.0
24.12
10
232
3.20
197
402
5.5
40.2
40.2
<0.1
0.975
<5
<50
14.7 B2
12
193
40
150
87
<1
<1
37
<1
<1
0.55 MI
<1
<1
CW-04 IMP
Bedrock
04/04/2018
6.0
23.10
17
176
2.27
316
521
4.6
57.3
57.3
<0.1
0.883 S1
<5
<50
13.5
7.5
133
22
160
53
<1
<1
27
<1
<1
0.18
0.399j
<1
CW-04 IMP
Bedrock
07/17/2018
5.9
23.30
21
186
2.80
370
575
0.9
51.9
51.9
<0.1
0.473 SI
<5
<50
12.9
8.8
141
26
180
15
<1
<1
29
<1
<1
0.22
<1
<1
CW-04
Bedrock
11/08/2018
5.9
22.55
15
180
1.36
158
363
8.8
55.4
55.4
<0.1
0.414 S1
<5
<50
13.3
6.1
116
17
140
198
<1
<1
24
<1
<1
0.053
<1
<1
CW-05
Bedrock
O1/22/2018
6.8
15.98
16
463
0.34
-7
198
7.3
165
165
<0.1
1.3 SI
<5
<50
56.6
41
172
6.3
280
22
<1
<1
56
<1
<1
<0.025
2.16
<1
CW-05 IMP
Bedrock
04/04/2018
6.7
10.96
19
436
1.65
273
478
3.3
169
169
<0.1
1.3 S1
<5
<50
53.8
39
170
7
280
19
<1
<1
55
<1
<1
<0.025
0.459j
0.805j
CW-OS IMP
Bedrock
07/17/2018
6.5
10.80
25
429
0.73
250
455
2.5
154
154
<0.1
1 SI
<5
<50
52.9
35
164
6.8
290
12
<1
<1
52
<1
<1
<0.025
0.443j
1.08
CW-05
Bedrock
11/06/2018
6.6
7.53
17
415
0.36
-13
192
7.3
151
151
<0.1
1 S1
<5
<50
53.5
33
163
6.6
260
38
<1
<1
55
<1
<1
<0.025
0.629j
0.964j
CW-06
Bedrock
O1/22/2018
6.8
16.43
15
846
0.30
-53
152
3.0
285
285
<0.1
2 SI
<5
<50
115
95
321
39
510
13
<1
<1
41
<1
<1
<0.025
<1
<1
CW-06 IMP
Bedrock
04/03/2018
6.6
15.45
13
885
0.41
226
431
1.7
289
289
<0.1
2 SI
<5
<50
104 M4
94
328
38
500
8
<1
<1
43
<1
<1
<0.025
<1
0.671j
CW-06 IMP
Bedrock
07/16/2018
6.5
14.20
19
865
0.27
315
520
3.7
293
293
<0.1
1.7 S1
<5
<50
99.1
92
326
36
480
19
<1
<1
43
<1
<1
<0.025
<1
0.741j
CW-06
Bedrock
11/07/2018
6.6
12.88
16
883
0.26
12
217
4.1
264
264
<0.1
1.9
<5
<50
110
94
340
37
480
21
<1
<1
42
<1
<1
<0.025
<1
0.628j
MW-02
Bedrock
O1/15/2018
5.9
29.42
14
326
0.37
92
297
1.6
1O1
SOS
<0.1
5.5
<5
<50
19.4 B2
22
218
18
210
73
<1
<1
73
<1
<1
<0.025
<1
4.34
MW-02
Bedrock
04/03/2018
6.0
27.92
17
298
0.18
65
270
1.2
113
113
<0.1
2.1 S1
<5
<50
18.2
16
192
17
190
42
<1
<1
60
<1
<1
<0.025
<1
2.44
MW-02
Bedrock
07/18/2018
5.6
27.41
22
330
0.60
355
560
4.4
108
SOS
<0.1
2.1 S1
5
<50
20.1
18
220
18
200
385
<1
0.343j
74
<1
<1
<0.025
<1
4.79
MW-02
Bedrock
11/06/2018
5.5
26.59
18
329
0.37
97
302
17.6
104
104
<0.1
S1
6
<50
18.9
14
191
18
ISO
1520
JF4
<1
<1
<0.025
0.575j
1.76
MW-03
Alluvial
O1/15/2018
6.1
6.60
11
326
1.77
207
412
1.2
65.9
65.9
<0.1
1.1 S1
<5
1040
25.7 B2
46
318
23
200
22 S1
<1
<1
53
<1
<1
0.19
<1
<1
MW-03
Alluvial
O1/16/2018
NM
NM
NM
NM
NM
NM
NM
NM
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-03
Alluvial
04/03/2018
6.0
6.47
13
353
0.82
296
501
0.5
78.2
78.2
<0.1
1.2 SI
<5
1010
29.4
47
330
23
190
7
<1
<1
56
<1
<1
0.14
<1
<1
MW-03
Alluvial
07/18/2018
5.8
6.80
19
333
1.41
565
770
0.2
64.7
64.7
<0.1
0.987 S1
<5
1230
25.1
47
325
25
200
4.668j
<1
<1
56
<1
<1
0.2
<1
<1
MW-03
Alluvial
11/08/2018
5.8
6.39
16
312
1.39
336
541
0.9
61.9
61.9
<0.1
0.937 S1
<5
1090
23.7
40
302
23
190
34
<1
<1
55
<1
<1
0.19
0.495j
<1
MW-03BR
Bedrock
01/22/2018
7.1
19.62
16
899
0.44
-75
130
1.5
237
237
<0.1
2 S1
<5
<50
139
150
394
11
570
23
<1
<1
40
<1
<1
<0.025
<1
<1
MW-03BR
Bedrock
04/04/2018
7.0
18.46
17
954
0.46
6
211
1.7
227
227
<0.1
2 SI
<5
<50
143
140
413
10
600
44 SI
<1
0.556j
53
<1
<1
<0.025
0.863j
<1
MW-03BR
Bedrock
07/17/2018
6.8
18.60
25
876
0.36
306
511
3.1
228
228
<0.1
1.7 S1
<5
<50
135
150
387
11
690
9
<1
<1
40
<1
<1
<0.025
<1
<1
MW-03BR
Bedrock
11/08/2018
6.6
18.09
15
917
0.32
-10
195
3.7
212
212
<0.1
1.7 SI
<5
<50
141
ISO
395
11
610
33
<1
<1
42
<1
<1
<0.025
0.505j
<1
MW-04
Bedrock
01/15/2018
6.4
35.82
13
309
0.58
124
329
9.4
101
101
<0.1
0.765 S1
19
<50
25.8 B2
9.1
95
39
200
151
<1
<1
8
<1
<1
0.068
1.34
<1
MW-04
Bedrock
04/04/2018
6.3
32.90
16
330
0.43
112
317
8.9
110
110
<0.1
1.1 SI
7
<50
28.4
7.9
109
38
210
153
1.6
<1
9
<1
<1
0.044
1.82
<1
MW-04
Bedrock
07/18/2018
6.3
31.55
20
344
1.78
408
613
1.5
116
116
<0.1
0.738 S1
<5
<50
33.9
8.7
124
38
210
20
<1
<1
6
<1
<1
0.028
<1
<1
MW-04
Bedrock
11/06/2018
6.6
30.30
17
406
0.66
63
268
2.4
136
136
<0.1
0.634 SI
<5
<50
50.6
8.1
167
35
220
6
<1
<1
7
<1
<1
0.14
<1
<1
MW-05BR
Bedrock
01/22/2018
7.2
17.51
15
642
0.29
-132
73
3.6
237
237
0.14
2 S1
13
<50
96.2
69
228
0.98
380
15
<1
<1
35
<1
<1
<0.025
<1
<1
MW-05BR
Bedrock
04/04/2018
7.0
13.05
18
641
0.41
132
337
7.5
243
243
<0.1
2.1 SI
25
<50
98.9
70
229
2.1
400
13
<1
1.04
37
<1
<1
<0.025
0.843j
0.563j
MW-05BR
Bedrock
07/17/2018
6.8
13.10
31
669
0.88
89
294
1.1
228
228
<0.1
1.7 S1
18
<50
103
68
229
2.4
460
10
<1
0.698j
35
<1
<1
<0.025
<1
<1
MW-05BR
Bedrock
11/06/2018
7.0
9.06
17
632
0.39
-130
75
2.4
215
215
<0.1
1.8 S1
17
<50
97.2
64
225
2.6
380
14
<1
1
34
<1
<1
<0.025
1.76
<1
MW-08BR
Bedrock
01/16/2018
6.5
36.74
14
749
0.23
-26
179
5.8
148
148
<0.1
2.2 S1
12
<50
68.5
120
354
38
460
80
<1
<1
22
<1
<1
<0.025
6.17
<1
MW-08BR
Bedrock
04/04/2018
6.4
35.85
16
777
0.36
-11
194
7.3
149
149
<0.1
1.9 SI
<5
<50
71.3
120
365
40
420
104
<1
<1
20
<1
<1
<0.025 MI
1.22
0.499j
MW-08BR
Bedrock
07/18/2018
6.1
35.61
23
707
0.72
409
614
1.2
139
139
<0.1
1.5 S1
<5
<50
69.7
120
357
40
480
32
0.811
0.5j
15
0.498j
0.389j
0.03
0.494j
0.821j
MW-08BR
Bedrock
11/06/2018
6.2
35.10
16
724
0.59
246
451
2.9
129
129
<0.1
1.6 SI
<5
<50
72.9
110
364
36
400
25
<1
<1
14
<1
<1
<0.025
0.734j
0.343j
MW-09BRL
Bedrock
O1/16/2018
7.1
37.40
8
840
0.70
115
320
9.5
108
108
<0.1
2.4 S1
<5
<50
40.3
83
203
12
300
229
<1
<1
29
<1
<1
0.039
<1
<1
MW-09BRL
Bedrock
04/04/2018
6.6
33.51
17
422
0.28
42
247
82.2
47.6
47.6
<0.1 MS
3 S1
<5
<50
13.1
16
71
9.6
240
4950
<1
0.571j
26
<1
<1
0.031
MW-09BRL
Bedrock
07/19/2018
6.7
34.34
18
650
0.51
-3
202
16.3
76.3
76.3
<0.1
2.1
<5
<50
24.8
46
128
9.5
220
859
0.681j
0.574j
16
<1
<1
<0.025MW-09BRL
Bedrock
11/06/2018
6.2
30.40
17
251
0.65
291
496
86.5
48.6
48.6
<0.1
2S1
7
<50
12.4
19
64
8.8
220
7160
<1
0.559j
18
<1
<1
0.028MW-104BRL
Bedrock
11/29/2018
7.2
Artesian
16
630
0.29
20
225
1.8
197
197
<0.1
0.825
<5
<50
112
55
957
55
390
14
<1
<1
29
<1
<1
<0.025MW-104BRM
Bedrock
11/29/2018
8.0
107.28
15
453
8.72
129
334
9.9
196
196
<0.1
0.782
13
<50
65.2
13
714
37
290
262
0.469j
0.871j
19
<1
<1
0.53
N-32O
MW-105BRM
Bedrock
11/29/2018
7.2
89.85
14
566
1.14
39
244
16.1
244
244
<0.1
1.4
6
<50
77.2
26
441
29
350
32
<1
<1
0.036MW-10BR
Bedrock
O1/15/2018
6.4
15.08
10
451
0.47
160
365
2.2
106
106
<0.1
2S1
<5
<50
29.3 B2
20
201
88
310
21 S1
<1
<1
<5
<1
<1
0.09MW-10BR
Bedrock
04/03/2018
6.2
14.40
14
457
0.36
197
402
1.1
113
113
<0.1
2.1S1
<5
<50
29.9
20
202
89
300
8
<1
<1
3.739j
<1
<1
0.049
Page 4 of 9

TABLE 3-3
2018 COMPREHENSIVE GROUNDWATER QUALITY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Analytical Parameter
INORGANIC PARAMETERS (TOTAL CONCENTRATION)
INORGANIC PARAMETERS (DISSOLVED CONCENTRATION WITH FILTER SIZE)
Copper
ug/L
Iron
ug/L
Lead
ug/L
Lithium
ug/L
Magnesium
mg/L
Manganese
ug/L
Mercury
ug/L
Molybdenum
ug/L
Nickel
ug/L
Nitrate +
Nitrite
mg-N/L
Potassium
mg/L
Selenium
ug/L
Sodium
mg/L
Thallium
ug/L
Vanadium
ug/L
Zinc
ug/L
Aluminum
(0.45u)
ug/L
Antimony
(0.45u)
ug/L
Arsenic
(0.45u)
ug/L
Barium
(0.45u)
ug/L
Beryllium
(0.45u)
ug/L
Boron
(0.45u)
ug/L
Cadmium
(0.45u)
ug/L
Chromium
(0.45u)
ug/L
Cobalt
(0.45u)
ug/L
Copper
(0.45u)
ug/L
Iron
(0.45u)
ug/L
Reporting Units
15A NCAC 02L Standard
1000
300
15
NE
NE
50
1
NE
100
NE
NE
20
NE
0.2*
0.3*
1000
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Provisional Background Threshold Values (Surficial Unit)
1.9
385
1
NE
0.753
253
0.2
3.15
3.03
0.798
3.78
1
5.49
0.2
0.974
227
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Provisional Background Threshold Values (Transition Zone Unit)
5
1319
1
NE
13.5
298
0.2
1
5
1 0.295
1 3.61
1
53.3
0.2
5.88
12
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Provisional Background Threshold Values (Bedrock Unit)
5
2550
1
1 NE
13.1
544
0.05
13.1
5
1 1.03
6.56
1
72.6
0.2
5.52
37.9
NE
NE
NE
NE
NE
NE
NE
NE
I NE
NE
NE
Sample ID
Well Screen
Location
Sample
Collection Date
Analytical Results
CW-02D
Bedrock
01/17/2018
<1
32
<1
<5
9
66
<0.05
2.3
<1
0.08
4.23
<1
18.7 B3
<0.2
1.23
<5
<5
<1
<1
26
<1
312
<1
<1
<1
<1
<10
CW-02D IMP
Bedrock
04/03/2018
2.69
575
0.862 j
4.684 j
8.9
22s
<0.05
2.06
12.1
0.082
4.17
<1
21
0.133 j
1.11
15
1.943 j
0.449 j
0.597 j
33
<1
410
<1
1.92
<1
0.403 j
6.452 j
CW-02D IMP
Bedrock
07/16/2018
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
CW-02D IMP
Bedrock
07/17/2018
0.976j
208
<1
2.4j
9.13
201
<0.05
2.25
2.74
0.038
4.59
<1
19.5
<0.2
1.45
10
2.641j
0.607j
0.366j
22
<1
245
<1
0.671j
<1
0.456 j,B2
4.324j
CW-02D
Bedrock
11/07/2018
20.1
45
<1
<5
8.99
31
0.017j
2.18
1.23
0.041
4.52
<1
18.1
<0.2
1.19
20
1.7391
<1
0.438j
22
<1
219
<1
0.336j
<1
0.3871
28
CW-03
Transition Zone
01/22/2018
<1
374
<1
6
7.36
19
<0.05
<1
<1
0.302
4.37
<1
41.9 B3
<0.2
2.14
5
<5
<1
<1
13
<1
<50
<1
<1
<1
<1
<10
CW-03 IMP
Transition Zone
04/04/2018
1.62
95 S1
<1
4.9451
7.48
13
<0.05
0.372j
<1
0.34
4.28
<1
41.4
<0.2
1.96
<5
6
<1
<1
17
<1
<50
<1
<1
<1
<1
15
CW-03 IMP
Transition Zone
07/17/2018
0.692j
238
<1
3.952j
7.16
15
<0.05
0.364j
0.495j
0.31
4.17
<1
41.7
<0.2
1.93
4.662j
<5
<1
<1
15
<1
<50
<1
<1
<1
<1
<10
CW-03
Transition Zone
11/08/2018
0.442j
133
<1
5
7.24
9
<0.05
0.3561
<1
0.306
4.1
<1
42.2
<0.2
1.81
<5
42
<1
<1
16
<1
<50
<1
<1
<1
<1
3.717j
CW-04
Bedrock
01/17/2018
<1
61
<1
<5
4.58
<5
<0.05
<1
1.91
0.084
1.19
<1
19.1 B3
<0.2
1.4
<5
<5
<1
<1
37
<1
<50
<1
<1
<1
<1
<10
CW-04 IMP
Bedrock
04/04/2018
0.695 j
25 SI
<1
3.953 j
3.5
<5
<0.05
0.358 j
0.539 j
0.16 S3
1.57
0.395 j
17.5
<0.2
1.11
4.136 j
2.017 j
<1
<1
27
<1
<50
<1
<1
<1
<1
<10
CW-04 IMP
Bedrock
07/17/2018
<1
12
<1
2.329 j
3.6
2.954 j
<0.05
0.279 j
0.642 j
0.118
1.3
0.336 j
17.5
<0.2
0.978
1.786 j
1.89 j
<1
<1
29
<1
<50
<1
0.357 j
<1
<1
11
CW-04
Bedrock
11/08/2018
<1
84
<1
3.83 j
3.34
<5
<0.05
0.455 j
<1
0.134
1.64
0.335 j
16.7
<0.2
1.22
4.048 j
2.0011
<1
<1
25
<1
<50
<1
<1
<1
<1
3.561 j
CW-05
Bedrock
01/22/2018
4.68
705
<1
7
7.77
669
<0.05
<1
2.15
<0.01
6.1
<1
19.2 B3
<0.2
<0.3
12
<5
<1
<1
52
<1
<50
<1
<1
<1
<1
347
CW-05 IMP
Bedrock
04/04/2018
1.11
326
<1
7
7.9
593
<0.05
0.89 j
1.94
<0.02
6.02
<1
19.1
<0.2
0.268 j
2.242 j
1.746 j
<1
<1
52
<1
<50
<1
<1
0.653 j
<1
207
CW-05 IMP
Bedrock
07/17/2018
<1
413
<1
5
7.49
803
<0.05
0.985j
0.711j
<0.01
5.8
<1
18.4
<0.2
0.244j
5
<5
<1
<1
50
<1
<50
<1
<1
0.874j
<1
217
CW-05
Bedrock
11/06/2018
<1
810
<1
5
7.44
787
0.024j
0.9861
0.343j
<0.01
5.71
<1
18
<0.2
0.149j
2.4511
2.871
<1
<1
53
<1
<50
<1
<1
0.9321
<1
401
CW-06
Bedrock
01/22/2018
<1
1520
<1
6
23.9
1330
<0.05
3.03
1.32
<0.01
9.18
<1
37.2 B3
<0.2
<0.3
<5
<5
<1
<1
41
<1
<50
<1
<1
<1
<1
1530
CW-06 IMP
Bedrock
04/03/2018
<1
1570
<1
7
21.8
1370
<0.05
2.83
1.27
<0.02
9.75
<1
37.1
<0.2
0.134j
<5
2.8253
<1
<1
43
<1
<50
<1
<1
0.677j
<1
1520
CW-06 IMP
Bedrock
07/16/2018
<1
1600
<1
6
22
1330
<0.05
2.83
1.31
<0.01
9.43
<1
36.5
<0.2
0.166 j,S1
7
4.47j
<1
<1
42
<1
<50
<1
<1
0.676j
<1
1500
CW-06
Bedrock
11/07/2018
<1
1670
<1
4.9711
20.8
1460
<0.05
2.93
0.863 j
<0.01
9.47
<1
38.8
<0.2
0.248 j
<5
2.684 j
<1
<1
41
<1
<50
<1
<1
0.7 j
<1
1550
MW-02
Bedrock
01/15/2018
<1
1020
<1
8
8.14
1350
<0.05
<1
3.56
0.16 SI
4.99
<1
26.2 B3
<0.2
0.53
<5
6
<1
<1
59
<1
<50
<1
<1
2.81
<1
587
MW-02
Bedrock
04/03/2018
<1
674
<1
6
8.02
761
<0.05
0.8411
2.94
0.18
3.78
<1
27.8
0.088j
0.467
<5
5
<1
<1
54
<1
<50
<1
<1
1.93
0.6711
472
MW-02
Bedrock
07/18/2018
3.4
1240
<1
8 B2
8.34
1310
<0.05
1.22
3.2
0.12
4.86
<1
29.1 B2
<0.2
0.76 S1
2.73 j,B2
5
<1
<1
59
<1
<50
<1
<1
2.62
<1
645
MW-02
Bedrock
11/06/2018
1.4
848
j <1
4.937j
7.78
537
0.019j
1.98
3.54
0.17
3.58
<1
31.4
<0.2
1.27
7
5
3.25
<1
<1
<50
<1
<1
1.5
<1
314
MW-03
Alluvial
01/15/2018
<1
35
<1
<5
8.55
1160
<0.05
<1
2.47
0.065 S1
2
<1
21.2 B3
<0.2
<0.3
<5
<5
<1
<1
53
<1
1020
<1
<1
<1
<1
13
MW-03
Alluvial
01/16/2018
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-03
Alluvial
04/03/2018
<1
8.159j
<1
<5
9.02
1530
<0.05
0.401j
2.81
0.053
2.14
<1
21.1
<0.2
0.233j
<5
<5
<1
<1
56
<1
1070
<1
<1
<1
<1
<10
MW-03
Alluvial
07/18/2018
1.86
4.883j
<1
3.0091
8.9
1040
<0.05
0.1461
2.12
0.074
2.13
<1
22.1 B2
<0.2
0.319 S1
<5
1.71
<1
<1
57
<1
1200
<1
<1
<1
<1
3.581j
MW-03
Alluvial
11/08/2018
<1
12
<1
1.9j
8.17
1320
0.022j
0.3j
2.19
0.052
2.09
<1
20.7
0.145j
0.335
8
<5
<1
<1
50
<1
991
<1
0.443j
<1
<1
<10
MW-03BR
Bedrock
01/22/2018
<1
329
<1
9
10.8
555
<0.05
<1
<1
<0.01
7.41
<1
20.6 B3
<0.2
<0.3
<5
<5
<1
<1
38
<1
<50
<1
<1
<1
<1
271
MW-03BR
Bedrock
04/04/2018
1.46 SI
694
<1
9
11
745
<0.05
1.78
0.38j
<0.02
7.51
<1
22.7
<0.2
0.627
<5
4.089j
<1
<1
39
<1
<50
<1
<1
<1
<1
254
MW-03BR
Bedrock
07/17/2018
<1
331
<1
7
10.6
564
<0.05
0.9511
<1
<0.01
7.2
<1
20.5
<0.2
0.249j
<5
1.748j
<1
<1
35
<1
<50
<1
<1
<1
<1
214
MW-03BR
Bedrock
11/08/2018
<1
361
<1
9
11.1
574
<0.05
0.981j
<1
<0.01
7.42
<1
20.9
<0.2
0.134j
<5
86
<1
<1
40
<1
22.379j
<1
<1
<1
<1
270
MW-04
Bedrock
01/15/2018
2
170
<1
6
7.44
72
<0.05
2.35
2.38
0.65
5.37
<1
19.7 B3
<0.2
0.968
21
<5
<1
<1
7
<1
<50
<1
<1
<1
<1
12
MW-04
Bedrock
04/04/2018
2.8
151 SI
0.445 j
4.971 j
7.38
63
<0.05
2.83
2.13
0.55
5.57
<1
20.2
<0.2
1.41
45
2.265 j
1.36
<1
7
<1
<50
<1
<1
<1
2.35
<10
MW-04
Bedrock
07/18/2018
4.2
25
<1
6 B2
7.42
53
<0.05
2.57
0.606 j
0.389
5.31
<1
19.8 B2
<0.2
0.6 S1
19 B2
2.052 j
<1
1.26
4.867 j
<1
<50
<1
<1
<1
1.15
4.288 j
MW-04
Bedrock
11/06/2018
1.2
6.703 j
<1
2.87 j
7.27
511
<0.05
4.13
1.27
0.052
5.17
<1
20.1
<0.2
0.655
37
16
<1
<1
3.863 j
<1
<50
<1
<1
<1
<1
<10
MW-05BR
Bedrock
01/22/2018
<1
5070
<1
<5
6.9
1790
<0.05
<1
<1
0.011
5.93
<1
16.8 B3
<0.2
<0.3
<5
13
<1
<1
36
<1
<50
<1
<1
<1
<1
8370
MW-05BR
Bedrock
04/04/2018
0.762j
8570
<1
3.698j
7.23
1910
<0.05
0.938j
0.823j
<0.02
5.56
<1
17.6
<0.2
0.4
<5
14
<1
0.557j
36
<1
<50
<1
<1
1.68
<1
10700
MW-05BR
Bedrock
07/17/2018
<1
5430
<1
3.559j
7.1
1750
<0.05
0.804j
<1
0.01
5.57
<1
18.7
<0.2
0.207j
2.0981
11
<1
0.681j
36
<1
<50
<1
<1
0.7521
<1
8190
MW-05BR
Bedrock
11/06/2018
<1
59s0
<1
2.427j
7
1780
0.019j
1.1
<1
0.0056j
5.37
<1
19.4
<0.2
0.119j
1.948j
8
<1
0.84j
35
<1
<50
<1
<1
0.951j
<1
8030
MW-08BR
Bedrock
01/16/2018
<1
320 S1
<1
<5
21.9
330
<0.05
2.85
4.95
0.23
5.68 B3
<1
28.9 BI
<0.2
0.849
9
<5
<1
<1
20
<1
<50
<1
1.05
<1
<1
146 SI
MW-08BR
Bedrock
04/04/2018
0.737j
219
<1
3.847j
22.4
258
<0.05
3.34
2.4
0.24 SI
5.34
<1
29.3
<0.2
0.943
28
2.415j
<1
<1
18
<1
<50
<1
<1
0.47j
<1
44
MW-08BR
Bedrock
07/18/2018
2.37
53
0.7261
5 B2
21.6
188
<0.05
2.46
2.5
0.252
4.78
0.552j
28.5 B2
0.608 S1
1.52 S1
4.843 j,B2
2.9j
<1
<1
15
<1
<50
<1
<1
0.3981
<1
<10
MW-08BR
Bedrock
11/06/2018
0.996j
104
<1
2.053j
23.2
156
0.018j
1.76
1.73
0.248
4.7
<1
28.6
<0.2
0.995
6
<5
<1
<1
14
<1
<50
<1
<1
0.394j
<1
<10
MW-09BRL
Bedrock
01/16/2018
2.66
211 51
<1
<5
11.6
491
<0.05
4.59
2.28
0.043
7.32 B3
<1
37.1 BI
<0.2
1.9
<5
<5
<1
<1
23
<1
<50
<1
<1
<1
2.47
24 51
MW-09BRL
Bedrock
04/04/2018
11.1
4620
1
7
3.66
187
0.022j
0.949j
3.44
0.25 S1
2.32
<1
14
<0.2
6.97
14
12
<1
<1
4.246j
<1
<50
<1
0.843j
<1
6.67
7.502j
MW-09BRL
Bedrock
07/19/2018
4.62
573
<1
4.656j
6.89
493
0.018j
2.41
2.98
0.062
4.12
<1
22.1
<0.2
1.97
4.067j
6
0.82j
0.354j
13
<1
<50
<1
<1
<1
2.2
12
MW-09BRL
Bedrock
11/06/2018
10.5
4620
0.695j
6
4.14
223
0.033j
1.43
2.84
0.202
2.6
<1
15.3
0.136j
6.63
9
9
<1
<1
4.508j
<1
<50
<1
<1
<1
8.25
20
MW-104BRL
Bedrock
11/29/2018
<1
224
<1
6
6.47
80
<0.05
2.22
<1
0.00441
4.73
<1
15.6
<0.2
<0.3
2.349j
3.362j
<1
<1
29
<1
<50
<1
<1
<1
<1
212
MW-104BRM
Bedrock
11/29/2018
0.501j
158
<1
42
4.48
17
<0.05
4.95
5.87
0.00791
23.3
<1
22.8
<0.2
3.63
22
77
0.527j
0.938j
18
<1
<50
<1
0.826j
<1
<1
3.513j
MW-105BRM
Bedrock
11/29/2018
0.874j
337
<1
8
16.9
1 3.23
0.011
7.8
<0.2
1.2
1
0.867j
<1
1
105
MW-10BR
Bedrock
01/15/2018
<1
12
<1
6
13.3
48
<0.05
<1
2.13
0.042 S1
4.04
<1
38.6 B3
<0.2
2.03
66
<5
<1
<1
<5
<1
<50
<1
<1
<1
<1
<10
MW-10BR
Bedrock
04/03/2018
<1
11
<1
4.863 j
13.7
53
<0.05
0.595 j
1.69
<0.02
4.12
<1
39.4
0.082 j
1.91
3.6 j
3.084 j
<1
<1
3.608 j
<1
<50
<1
<1
<1
<1
<10
Page 5 of 9

TABLE 3-3
2018 COMPREHENSIVE GROUNDWATER QUALITY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Analytical Parameter
INORGANIC PARAMETERS (DISSOLVED CONCENTRATION WITH FILTER SIZE)
RADIONUCLIDES
OTHER PARAMETERS
Lead
(0.45u)
ug/L
Lithium
(0.45u)
ug/L
Manganese
(0.45u)
ug/L
Mercury
(0.45u)
ug/L
Molybdenum
(0.45u)
ug/L
Nickel
(0.45u)
ug/L
Phosphorus
(0.45u)
mg/L
Selenium
(0.45u)
ug/L
Silver
(0.45u)
ug/L
Strontium
(0.45u)
ug/L
Thallium
(0.45u)
ug/L
Vanadium
(0.45u)
ug/L
Zinc
(0.45u)
ug/L
Radium-226
pCi/L
Radium-228
pCi/L
Total Radium
pCi/L
Uranium-238
ug/mL
Total Uranium
ug/mL
Carbonate
Alkalinity
mg/L
Fluoride
mg/L
Phosphorus
mg/L
Reporting Units
15A NCAC 02L Standard
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
5^
NE
0.03^
NE
2
NE
Provisional Background Threshold Values (Surficial Unit)
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
4
NE
0.000367
5
NE
NE
Provisional Background Threshold Values (Transition Zone Unit)
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
9
NE
0.001
5
NE
NE
Provisional Background Threshold Values (Bedrock Unit)
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
7.6
NE
0.00203
5
NE
NE
Sample ID
Well Screen
Location
Sample
Collection Date
Analytical Results
CW-02D
Bedrock
01/17/2018
<1
<5
<5
<0.05
2.34
<1
<0.05
<1
NA
358
<0.2
0.908
6
0.41 R1
<1
0.41
NA
0.00296
<5
0.18
<0.05
CW-02D IMP
Bedrock
04/03/2018
<1
3.792j
16
<0.05
1.86
2.14
<0.05
<1
NA
319
0.089j
0.427
8
0.405 U
0.229 U
0.634
NA
0.00196
<5
0.12
0.055
CW-02D IMP
Bedrock
07/16/2018
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
0.347
0.449 U
0.796
NA
0.00189
NA
NA
NA
CW-02D IMP
Bedrock
07/17/2018
<1
1.972j
119
<0.05
2.03
0.728j
<0.05
<1
NA
371
<0.2
0.957
6
NA
NA
NA
NA
NA
<5
0.16
<0.05
CW-02D
Bedrock
11/07/2018
<1
<5
174
<0.05
2.3
0.4441
<0.05
<1
NA
460
<0.2
0.997
4.485j
0.159 U
0.457
0.616
0.00252
0.00252
<5
0.12
<0.05
CW-03
Transition Zone
01/22/2018
<1
6
<5
<0.05
<1
<1
0.13
<1
NA
308
<0.2 B3
1.46
<5
NA
NA
NA
NA
NA
<5
0.24
0.14
CW-03 IMP
Transition Zone
04/04/2018
<1
2.623 j
4.249 j
<0.05
0.385 j
<1
0.15
<1
NA
313
<0.2
1.48
2.089 j
NA
NA
NA
NA
NA
<5
0.21
0.14
CW-03 IMP
Transition Zone
07/17/2018
<1
3.912j
<5
<0.05
0.28j
0.39j
0.13
<1
NA
289
<0.2
1.27
<5
NA
NA
NA
NA
NA
<5
0.16
0.14
CW-03
Transition Zone
11/08/2018
<1
3.3261
<5
0.0181
0.357j
<1
0.18
<1
NA
308
<0.2
1.44
4.031j
NA
NA
NA
NA
NA
<5
0.1876j
0.15
CW-04
Bedrock
01/17/2018
<1
<5
<5
<0.05
<1
1.27
0.19
<1
NA
189
<0.2
1.06
<5
NA
NA
NA
NA
NA
<5
0.13
0.19
CW-04 IMP
Bedrock
04/04/2018
<1
<5
<5
<0.05
0.306 j
0.604 j
0.19
0.435 j
NA
132
<0.2
1.03
<5
NA
NA
NA
NA
NA
<5
0.12
0.18
CW-04 IMP
Bedrock
07/17/2018
<1
2.522 j
2.065 j
<0.05
0.219 j
0.711 j
0.17
0.37 j
NA
147
<0.2
0.838
<5
NA
NA
NA
NA
NA
<5
0.11
0.17
CW-04
Bedrock
11/08/2018
<1
1.7061
<5
0.0181
0.376j
<1
0.19
<1
NA
114
<0.2
1
<5
NA
NA
NA
NA
NA
<5
0.13
0.18
CW-05
Bedrock
01/22/2018
<1
6
647
<0.05
<1
<1
0.12
<1
NA
173
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
0.29
0.21
CW-05 IMP
Bedrock
04/04/2018
<1
4.1881
554
<0.05
0.885j
1.67
0.11
<1
NA
169
<0.2
0.182j
2.306j
NA
NA
NA
NA
NA
<5
0.27
0.12
CW-05 IMP
Bedrock
07/17/2018
<1
4.789 j
688
<0.05
0.89 j
0.711 j
0.1
<1
NA
158
<0.2
<0.3
2.49 j
NA
NA
NA
NA
NA
<5
0.26
0.14 MI
CW-05
Bedrock
11/06/2018
<1
5
767
<0.05
0.993j
<1
0.15
<1
NA
161
<0.2
0.225j
2.637j
NA
NA
NA
NA
NA
<5
0.24
0.26
CW-06
Bedrock
01/22/2018
<1
6
1370
<0.05
2.94
1.03
0.09
<1
NA
330
<0.2 B3
<0.3
<5
47.8
10.1
57.9
NA
0.00026
<5
0.39
0.094
CW-06 IMP
Bedrock
04/03/2018
<1
6
1360
<0.05
2.96
1.27
0.1
<1
NA
329
<0.2
<0.3
<5
1.39
10.6
11.99
NA
0.000245
<5
0.35
0.1
CW-06 IMP
Bedrock
07/16/2018
<1
7
1330
<0.05
2.64
1.3
0.088
<1
NA
320
0.113j
<0.3
3.644j
22.1
5.79
27.89
NA
0.000179j
<5
0.29
0.11
CW-06
Bedrock
11/07/2018
<1
6
1420
<0.05
2.9
1.37
0.11
<1
NA
331
<0.2
0.227j
1.727j
110
8.76
118.76
0.000216
0.000216
<5
0.26
0.1
MW-02
Bedrock
01/15/2018
<1
6
762
<0.05
1.01
2.69
0.14
<1
NA
189
<0.2 B2
0.541
<5
NA
NA
NA
NA
NA
<5
0.23
0.16
MW-02
Bedrock
04/03/2018
<1
6
575
<0.05
0.937j
2.89
0.17
<1
NA
185
0.143j
0.449
2.948j
NA
NA
NA
NA
NA
<5
0.19
0.18
MW-02
Bedrock
07/18/2018
<1
4.322j
815
<0.05
1.09
2.48
0.15
<1
NA
193
<0.2
0.397 B3
2.854j
NA
NA
NA
NA
NA
<5
0.23
0.15
MW-02
Bedrock
11/06/2018
<1
3.452j
455
<0.05
1.98
0.17
<1
NA
178
<0.2
0.68
3.185j
NA
A
NA
NA
0.24
0.18
MW-03
Alluvial
01/15/2018
<1
<5
974
<0.05 M2
<1
2.11
<0.05
<1
NA
324
<0.2 B2
0.301
<5
NA
NA
NA
NA
NA
<5
0.17
<0.05
MW-03
Alluvial
01/16/2018
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
3.39
<1
3.39
NA
0.000134 j
NA
NA
NA
MW-03
Alluvial
04/03/2018
<1
<5
1230
<0.05
0.361j
2.6
<0.05
<1
NA
338
<0.2
0.159j
<5
4.58
0.487
5.067
NA
<0.0002
<5
0.12
<0.05
MW-03
Alluvial
07/18/2018
<1
<5
1030
<0.05
0.191j
2.01
<0.05
<1
NA
323
<0.2
0.31 B3
2.23j
6.5
-0.015 U
6.485
NA
<0.0002
<5
0.15
<0.05
MW-03
Alluvial
11/08/2018
<1
<5
1210
<0.05
0.161j
2.06
<0.05
<1
NA
281
<0.2
0.171j
3.58j
0.454 U
0.522
0.976
<0.0002
<0.0002
<5
0.12
<0.05 M1
MW-03BR
Bedrock
01/22/2018
<1
8
538
<0.05
<1
<1
<0.05
<1
NA
399
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
<0.5
<0.05
MW-03BR
Bedrock
04/04/2018
<1
7
538
<0.05
0.852j
<1
0.058
<1
NA
397
<0.2
0.163j
<5
NA
NA
NA
NA
NA
<5
0.348j
0.051
MW-03BR
Bedrock
07/17/2018
<1
6
486
<0.05
0.736j
<1
<0.05
<1
NA
362
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
0.24
<0.05
MW-03BR
Bedrock
11/08/2018
<1
7
557
0.018j
0.732j
<1
0.064
<1
NA
406
<0.2
<0.3
4.431j
NA
NA
NA
NA
NA
<5
0.28j
0.06
MW-04
Bedrock
01/15/2018
<1
5
36
<0.05
2.44
1.3
0.066
<1
NA
96
<0.2 B2
0.721
14
NA
NA
NA
NA
NA
<5
0.24
0.067
MW-04
Bedrock
04/04/2018
<1
2.824j
25
<0.05
2.69
0.954j
0.066
0.439j
NA
102
0.112j
0.599
40
NA
NA
NA
NA
NA
<5
0.22
0.066
MW-04
Bedrock
07/18/2018
<1
3.3231
12
<0.05
2.54
0.487j
<0.05
<1
NA
114
<0.2
0.518 B3
15
NA
NA
NA
NA
NA
<5
0.21
0.051
MW-04
Bedrock
11/06/2018
<1
3.294j
112
<0.05
3.32
0.506j
0.064
<1
NA
127
<0.2
0.638
20
NA
NA
NA
NA
NA
<5
0.19
<0.05
MW-05BR
Bedrock
01/22/2018
<1
<5
1820
<0.05
<1
<1
0.085
<1
NA
228
<0.2 B3
<0.3
<5
NA
NA
NA
NA
NA
<5
0.25
0.091
MW-05BR
Bedrock
04/04/2018
<1
1.894j
1810
<0.05
2.3
0.442j
0.11
<1
NA
219
<0.2
0.11j
<5
NA
NA
NA
NA
NA
<5
0.2
0.11
MW-05BR
Bedrock
07/17/2018
<1
3.1961
1820
<0.05
0.849j
<1
0.079
<1
NA
227
<0.2
0.121j
<5
NA
NA
NA
NA
NA
<5
0.19
0.11
MW-05BR
Bedrock
11/06/2018
<1
2.935j
1860
0.021j
2.2
<1
0.12
<1
NA
219
<0.2
0.147j
<5
NA
NA
NA
NA
NA
<5
0.18
0.12
MW-08BR
Bedrock
01/16/2018
<1
<5
299
<0.05
2.65
3.04
0.051
<1
NA
352
<0.2
0.667
<5
NA
NA
NA
NA
NA
<5
0.2
0.075 SI
MW-08BR
Bedrock
04/04/2018
<1
2.078j
242
<0.05
2.78
2.05
0.063
<1
NA
358
<0.2
0.757
38
NA
NA
NA
NA
NA
<5
0.162j
0.071
MW-08BR
Bedrock
07/18/2018
<1
2j
198
<0.05
1.89
1.81
0.055
<1
NA
360
<0.2
0.76 B3
4j
NA
NA
NA
NA
NA
<5
0.1566j
0.058
MW-08BR
Bedrock
11/06/2018
<1
2.21j
180
<0.05
1.8
1.43
0.069
<1
NA
353
<0.2
0.974
4.257j
NA
NA
NA
NA
NA
<5
0.1314j
0.074
MW-09BRL
Bedrock
01/16/2018
<1
<5
471
<0.05
3.62
1.79
0.13
<1
NA
177
<0.2
1.44
<5
NA
NA
NA
NA
NA
<5
0.19
0.11 S1
MW-09BRL
Bedrock
04/04/2018
<1
<5
98
<0.05
0.72 j
1.38
0.26
<1
NA
46
<0.2
1.09
19
NA
NA
NA
NA
NA
<5
0.15
0.3
MW-09BRL
Bedrock
07/19/2018
<1
4.448j
423
<0.05
2.22
1.41
0.22
<1
NA
116
<0.2
1.06
2.238j
NA
NA
NA
NA
NA
<5
0.13
0.22
MW-09BRL
Bedrock
11/06/2018
<1
2.161 j
163
0.02 j
1.6
1.19
0.34
<1
NA
45
<0.2
1.27
8
NA
NA
NA
NA
<5
0.15
0.4
MW-104BRL
Bedrock
11/29/2018
<1
4.124j
81
<0.05
2.29
<1
<0.05
<1
NA
989
<0.2
<0.3
<5
0.71
2.99
3.7
0.00124
0.00124
<5
0.78
<0.05
MW-104BRM
Bedrock
11/29/2018
<1
43
14
<0.05
4.9
2.84
<0.05
<1
NA
707
<0.2
3.32
16
3.21
-0.121 U
3.089
0.00306
0.00306
<5
1.3
<0.05
MW-105BRM
Bedrock
11/29/2018
<1
7
<0.05
<1
NA
NA
200
<0.2
<0.2 B2
.84
2.13
0.671
0.11 U
<1
0.588
0.00133
NA
0.00133
<0.0002
<5
0.39
0.22
MW-10BR
Bedrock
01/15/2018
<1
6
44
<0.05
<1
1.46
0.22
<1
7
0.588
MW-10BR
Bedrock
04/03/2018
<1
5
54
<0.05
0.655j
1.67
0.22
<1
NA
204
0.155j
1.93
4.755j
2.38
0.26 U
2.64
NA
0.00007981
<5
0.39
0.22
Page 6 of 9

TABLE 3-3
2018 COMPREHENSIVE GROUNDWATER QUALITY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
FIELD PARAMETERS
WATER QUALITY PARAMETERS
SELECTED 40CFR257 APPENDIX III CONSTITUENTS plus Sr
INORGANIC PARAMETERS (TOTAL CONCENTRATION)
Analytical Parameter
pH
Water
Level
Temp
Spec
Cond
DO
ORP
Eh
Turbidity
Alkalinity
carBi-
bonate
Alkalinity
Sulfide
Total
Organic
Carbon
Total
Suspended
Solids
Boron
Calcium
Chloride
Strontium
Sulfate
Total
Dissolved
Solids
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
(VI)
Chromium
Cobalt
Reporting Units
S.U.
ft
Deg C
umhos/cm
mg/L
mV
mV
NTUs
mg/L
mg/L
mg/L
mg/L
mg/L
ug/L
mg/L
mg/L
ug/L
mg/L
mg/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
15A NCAC 02L Standard
6.5-8.5
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
700
NE
250
NE
250
Soo
NE
1*
10
700
4*
2
10
10
1*
Provisional Background Threshold Values (Surficial Unit)
4.9-6.5
NE
NE
NE
NE
NE
NE
NE
13
13
0.1
2
NE
So
2.89
3.3
25
1.6
85
566
1
1
19
1
1
0.088
3.23
1.02
Provisional Background Threshold Values (Transition Zone Unit)
5.7-6.5
NE
NE
NE
NE
NE
NE
NE
302
302
0.1
1.8
NE
50
59.2
33.3
391
7.5
430
490
1
1
78.3
1
1
1.26
6
1
Provisional Background Threshold Values (Bedrock Unit)
5.0-7.3
NE
NE
NE
NE
NE
NE
NE
223
223
0.1
1.01
NE
50
73.3
43
418
18
340
536
1
1
97
1
1
0.4
7
1.19
Sample ID
Well Screen
Location
Sample
Collection Date
Analytical Results
MW-10BR
Bedrock
07/18/2018
6.0
12.91
21
448
0.35
184
389
0.5
102
102
<0.1 RI
1.9 51
<5
<50
29.1
21
200
87
290
6
<1
<1
4.689j
<1
<1
0.16
<1
<1
MW-10BR
Bedrock
11/06/2018
6.1
12.26
18
456
0.43
296
501
1.3
98.9
98.9
<0.1
1.8 S1
<5
<50
31.3
19
207
85
290
23
<1
<1
4.263j
<1
<1
0.14
0.404j
<1
MW-12D
Transition Zone
01/16/2018
6.2
34.71
14
128
3.46
96
301
7.0
54.9
54.9
<0.1
0.689 51
<5
<50
11.3
4.2
85
1.1
98
31
<1
<1
14
<1
<1
0.77
<1
<1
MW-12D
Transition Zone
04/02/2018
6.0
34.28
17
129
3.28
104
309
3.7
59.9
59.9
<0.1
0.495 SI
<5
<50
12.4
4.1
91
1.1
65
38
<1
<1
15
<1
<1
0.64 M1
0.882 j
<1
MW-12D
Transition Zone
07/18/2018
5.8
32.84
18
132
3.41
171
376
2.6
61.9
61.9
<0.1
0.254 SI
<5
<50
12.1
4.3
92
1.1
110
22
<1
<1
16
<1
<1
0.96
0.791j
<1
MW-12D
Transition Zone
11/07/2018
6.0
32.60
16
151
3.85
316
521
8.1
53.8
53.8
<0.1
0.264 S1
<5
<50
12.7
4.4
92
1.1
86
82
<1
<1
15
<1
<1
0.82
1.02
<1
MW-12S
Saprolite
01/16/2018
6.0
34.44
13 IN
45
1 3.06
85
1 29W
32.2
13.8
13.8
0.1
2.2 51
31
<50
1.43
2.1
19
1 <1 V
0.03
1.42
1.98
MW-12S
Saprolite
04/02/2018
5.9
33.99
18
46
0.32
97
302
9.9
14.5
14.5
<0.1
5.8
5
<50
0.843
1.6
12
1.6
32
370
<1
0.908j
12
<1
<1
0.052
<1
0.695j
MW-12S
Saprolite
07/18/2018
5.2
33.49
21
50
0.35
165
370
9.9
14.6
14.6
<0.1
1.9 S1
<5
<50
2.16
2.5
21
1.6
52
490
<1
0.52 j
17
<1
<1
0.045
0.851 j
0.667 j
MW-12S
Saprolite
11/07/2018
5.8
32.40
15
61
1.28
318
523
15.3
14.6
14.6
<0.1
3.4
6
<50
2.86
2.4
18
1.3
<25
1020
<1
0.53 j
16
<1
<1
0.063
0.996 j
0.948 j
MW-13BR
Bedrock
01/16/2018
7.0
30.83
14
494
0.46
-79
126
8.7
197
197
<0.1
0.98851
10
<50
61.3
29
322
15
290
134
<1
<1
22
<1
<1
<0.025
5.7
6.53
MW-13BR
Bedrock
04/04/2018
6.9
30.22
17
493
0.43
39
244
9.8
205
205
<0.1
0.781 S1
11
<50
65.2
30
333
16
290
162
0.581j
<1
22
<1
<1
<0.025
3.96
4.77
MW-13BR
Bedrock
07/18/2018
6.8
30.50
22
1.92
-84
121
14.9
206
206 jjj<O.1
0.405 SI
36
<50
64.2
29
341
16
310
1040
0.37j
<1
40
<1
<1
<0.025
3.48
5.99
MW-13BR
Bedrock
11/08/2018
6.8
29.55
18
473
0.46
-82
123
4.7
184
184
0.11
0.496 S1
8
<50
62.3
28
319
16
280
111
<1
<1
18
<1
<1
0.045
0.727j
4.67
MW-14BR
Bedrock
01/22/2018
6.9
21.47
16
315
2.56
195
400
2.2
138
138
<0.1
1.1 51
<5
<50
15
14
230
9.1
220
42
<1
<1
20
<1
<1
0.054
<1
<1
MW-14BR
Bedrock
04/04/2018
6.6
18.66
16
276
2.42
196
401
2.3
115
115
<0.1
1.1 SS
<5
<50
16
13
161
8.9
200
85
<1
0.621j
18
<1
<1
0.025
<1
<1
MW-14BR
Bedrock
07/18/2018
6.5
19.39
22
273
0.85
79
284
5.8
112
112
<0.1
0.793 S1
<5
<50
15.6
14
147
9.2
190
118
<1
0.538j
17
<1
<1
<0.025 M1
<1
0.581j
MW-14BR
Bedrock
11/07/2018
6.3
17.94
18
276
0.48
180
385
9.2
SOS
SOS
<0.1
0.8 SI
<5
<50
14.2
13
166
9.5
160
236
<1
0.582j
16
<1
<1
0.028
<1
1.53
MW-16BR
Bedrock
01/22/2018
7.7
7.07
13
355
0.17
-200
5
2.6
157
157
0.12
8.4 B3
<5
<50
38.2
8.4
140
0.92
180
13
<1
<1
15
<1
<1
<0.025
<1
<1
MW-16BR
Bedrock
04/03/2018
7.7
5.89
11
334
0.21
-106
99
4.0
166
166
<0.1
2.5 SI
<5
26.161j
38.2
8.2
140
1.4 SI
180
11
<1
0.392j
15
<1
<1
<0.025
<1
<1
MW-16BR
Bedrock
07/18/2018
7.5
7.22
20
316
0.16
-157
48
9.8
156
156
<0.1
0.823 51
6
25.78j
34.7
8.6
132
0.75
180
12
<1
0.428j
15
<1
<1
<0.025
<1
<1
MW-16BR
Bedrock
11/06/2018
7.5
4.52
18
309
0.35
-179
26
9.6
147
147
<0.1
0.765 SI
7
22.397j
37.3
8.2
135
1.4
160
11
<1
<1
14
<1
<1
0.025
<1
<1
MW-16D
Transition Zone
01/22/2018
6.9
6.59
14
241
1.55
166
371
2.4
82.8
82.8
<0.1
0.293 51
<5
<50
26.6
12
175
8.7
150
44
<1
<1
<5
<1
<1
0.14 M1
<1
<1
MW-16D
Transition Zone
04/03/2018
7.1
5.59
13
230
1.99
8
213
4.5
80.6
80.6
<0.1
0.565 SI
6
<50
25.8
11
168
7.7
140
83
<1
<1
4.04 j
<1
<1
0.15
<1
<1
MW-16D
Transition Zone
07/18/2018
7.0
6.89
18
227
1.90
72
277
9.5
80.7
80.7
<0.1
0.172 SI
5
<50
26.3
11
170
7.7
140
134
<1
<1
4.956j
<1
<1
0.14
0.37j
<1
MW-16D
Transition Zone
11/06/2018
6.9
4.08
18
226
2.20
110
315
2.9
72.8
72.8
<0.1
0.293 SI
7
<50
27
11
175
7.3
130
140
<1
<1
4.907j
<1
<1
0.15
0.447j
<1
MW-16S
Alluvial
01/22/2018
6.2
5.90
30
192
2.76
188
393
3.0
41.8
41.8
<0.1
1.1 51
<5
402
16.4
25
215
15
100
7
<1
<1
110
<1
<1
<0.025
<1
<1
MW-16S
Alluvial
04/03/2018
6.1
5.60
10
155
2.69
169
374
5.5
23.9
23.9
<0.1
0.801 SI
<5
190
11.8
14
148
11
80
7
<1
<1
75
<1
<1
<0.025
<1
<1
MW-16S
Alluvial
07/18/2018
5.6
6.65
21
121
0.50
166
371
7.8
24.8
24.8
<0.1
0.497 51
<5
164
10.4
9.7
133
8.7
80
21
0.364j
<1
75
<1
<1
<0.025
<1
<1
MW-16S
Alluvial
11/06/2018
5.7
3.84
18
121
1.19
196
401
1.9
30.9
30.9
<0.1
0.536 SI
<5
98
9.64
1 4.1
126
9.6
51
12
<1
<1
71
<1
<1
0.044
<1
<1
MW-18BR
Bedrock
01/15/2018
7.3
24.76
8
626
0.61
-90
115
2.7
268
268
<0.1
0.898 51
<5
<50
106
67
462
14
400
106
<1
<1
96
<1
<1
<0.025 RS
<1
<1
MW-18BR
Bedrock
04/04/2018
7.1
20.86
18
697
0.36
-79
126
5.2
250
250
<0.1
1.2 SI
<5
<50
103
70
481
15
400
15
<1
1.01
98
<1
<1
<0.025
<1
<1
MW-18BR
Bedrock
07/18/2018
7.2
20.47
23
716
0.33
-93
112
4.0
512
512
<0.1
0.892 51
<5
<50
95.5
69
444
21
420
39
<1
2.51
90
<1
<1
<0.025
<1
<1
MW-18BR
Bedrock
09/12/2018
6.9
20.89
21
702
0.40
-38
167
2.3
248
248
<0.1
1.3
<5
<50
96.8 B2
65
450
17
410
18
<1
2.01
91
<1
<1
<0.025
<1
<1
MW-18BR
Bedrock
11/06/2018
7.1
11.01
19
720
0.47
121
326
4.9
244
244
<0.1
0.878 S1
6
<50
99.3
66
462
18
380
111
<1
1.96
92
<1
<1
<0.025
<1
<1
MW-18BR
Bedrock
12/05/2018
7.1
11.78
11
703
0.45
2
207
5.8
235
235
<0.1
0.825
<5
<50
97.3 B2
67
448
17
390
82
<1
1.29
91
<1
<1
<0.025
<1
<1
MW-18D
Transition Zone
01/15/2018
6.4
27.12
12
387
0.37
49
254
2.6
128
128
<0.1
1.2 51
<5
<50
44.5 B2
25
161
38
270
137 51
<1
<1
<5
<1
<1
<0.025
<1
<1
MW-18D
Transition Zone
04/04/2018
6.3
24.33
16
415
0.26
99
304
6.4
132 M1
132
<0.1
1.4 SI
<5
<50
46.5
25
168
38
280
202 SI
<1
<1
3.713j
<1
<1
<0.025
0.383j
<1
MW-18D
Transition Zone
07/18/2018
6.3
23.76
22
407
0.42
86
291
9.1
126
126
<0.1
1.1 51
<5
<50
40.4
25
156
37
270
40
<1
<1
3.536j
<1
0.385j
0.034
<1
<1
MW-18D
Transition Zone
09/12/2018
6.0
24.04
19
409
0.22
88
293
3.1
123
123
<0.1
1.1
<5
<50
40.6 B2
23
158
36
260
14
<1
<1
3.691j
<1
<1
<0.025
<1
<1
MW-18D
Transition Zone
11/06/2018
6.2
12.68
18
421
0.31
297
502
6.2
121
121
<0.1
1 51
<5
<50
46.7
22
172
36
260
932
<1
<1
6
<1
<1
<0.025
0.594j
<1
MW-18D
Transition Zone
12/05/2018
6.1
12.63
10
387
0.39
178
383
9.3
114
114
<0.1
1
<5
<50
39.6 B2
23
152
37
250
332
<1
<1
4.775j
<1
<1
0.058
0.528j
<1
MW-19BR
Bedrock
01/15/2018
6.9
12.37
7
935
0.53
-123
82
0.6
247
247
<0.1
2 S1
<5
<50
124 B2,M4
140
421
57
570
46 S1
<1
<1
56
<1
<1
<0.025
<1
<1
MW-19BR
Bedrock
04/04/2018
6.9
9.82
17
990
0.28
-6
199
1.2
251
251
<0.1
2.1 SI
<5
<50
119
150
439
60
580
4.845j
<1
0.405j
58
<1
<1
<0.025
<1
0.404j
MW-19BR
Bedrock
07/18/2018
6.8
10.27
20
980
0.34
-52
153
2.7
475
475
<0.1
1.8 51
<5
<50
118
150
440
60
670
9
<1
0.415j
58
<1
<1
<0.025
<1
0.387j
MW-19BR
Bedrock
11/06/2018
6.7
8.80
17
1098
0.34
108
313
8.7
230
230
<0.1
1.9 S1
<5
<50
124
130
436
56
560
16
<1
0.442j
58
<1
<1
<0.025
<1
0.41j
MW-19D
Transition Zone
01/15/2018
6.8
11.04
10
841
0.31
-76
129
1.7
207
207
<0.1
1.8 51
<5
<50
97 B2
130
359
58
SID
50 51
<1
<1
60
<1
<1
<0.025
<1
<1
MW-19D
Transition Zone
04/04/2018
6.6
8.34
16
890
0.27
144
349
9.8
199
199
<0.1
2 SI
<5
<50
94.3
130
363
63
500
21
<1
<1
61
<1
<1
<0.025
<1
0.832j
MW-19D
Transition Zone
07/18/2018
6.7
8.97
19
881
0.65
-33
172
4.3
208
208
<0.1
1.751
<Sj
<50
1 92.1
1 130
357
62
580
12
<1
<1
58
<1
<1
<0.025
<1
0.757j
MW-19D
Transition Zone
11/06/2018
6.8
7.05
1 18
1 1114
1 0.22
1 106
1 3111
9.7
199
199
<0.1
1.8 SS
1 6
1 <50
1 98.7
1 120
1 374
59
470
21
1 <1
1 0.39j
61
<1
<1
<0.025
0.354j
0.77j
Prepared by: BER Checked by: JAW
Page 7 of 9

TABLE 3-3
2018 COMPREHENSIVE GROUNDWATER QUALITY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Analytical Parameter
INORGANIC PARAMETERS (TOTAL CONCENTRATION)
INORGANIC PARAMETERS (DISSOLVED CONCENTRATION WITH FILTER SIZE)
Copper
ug/L
Iron
ug/L
Lead
ug/L
Lithium
ug/L
Magnesium
mg/L
Manganese
ug/L
Mercury
ug/L
Molybdenum
ug/L
Nickel
ug/L
Nitrate +
Nitrite
mg-N/L
Potassium
mg/L
Selenium
ug/L
Sodium
mg/L
Thallium
ug/L
Vanadium
ug/L
Zinc
ug/L
Aluminum
(0.45u)
ug/L
Antimony
(0.45u)
ug/L
Arsenic
(0.45u)
ug/L
Barium
(0.45u)
ug/L
Beryllium
(0.45u)
ug/L
Boron
(0.45u)
ug/L
Cadmium
(0.45u)
ug/L
Chromium
(0.45u)
ug/L
Cobalt
(0.45u)
ug/L
Copper
(0.45u)
ug/L
Iron
(0.45u)
ug/L
Reporting Units
1SA NCAC 02L Standard
1000
300
15
NE
NE
50
1
NE
100
NE
NE
20
NE
0.2*
0.3*
1000
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Provisional Background Threshold Values (Surficial Unit)
1.9
385
1
NE
0.753
253
0.2
3.15
3.03
0.798
3.78
1
5.49
0.2
0.974
227
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Provisional Background Threshold Values (Transition Zone Unit)
5
1319
1
NE
13.5
298
0.2
1
5
1 0.295
1 3.61
1
53.3
0.2
5.88
12
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Provisional Background Threshold Values (Bedrock Unit)
5
2550
1
1 NE
13.1
544
0.05
13.1
5
1 1.03
1 6.56
1
72.6
0.2
5.52
37.9
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
Sample ID
Well Screen
Location
Sample
Collection Date
Analytical Results
MW-10BR
Bedrock
07/18/2018
2.43
7.238j
<1
6 B2
13.4
40
0.05
0.617j
1.79
0.062
4.17
<1
38.7 B2
0.152 j,S1
1.93 S1
27 B2
2.738j
<1
<1
7
<1
<50
<1
0.385j
<1
<1
<10
MW-10BR
Bedrock
11/06/2018
0.486 j
27
<1
3.935 j
14
34
0.039 j
0.622 j
1.44
0.019 M1
4
<1
38.9
0.171 j
2.05
17
2.67 j
<1
<1
4.296 j
<1
<50
<1
<1
<1
0.402 j
<10
MW-12D
Transition Zone
01/16/2018
<1
92 S1
<1
<5
3.03
20
<0.05
<1
<1
0.23
1.33 B3
<1
9.03 B1
<0.2
0.741
<5
<5
<1
<1
14
<1
<50
<1
<1
<1
<1
<10
MW-12D
Transition Zone
04/02/2018
1.66
89
<1
<5
3.36
22
<0.05
0.604j
1.23
0.25
1.41
<1
9.35
0.109j
0.709
3.621j
<5
<1
<1
16
<1
<50
<1
0.815j
<1
0.463j
<10
MW-12D
Transition Zone
07/18/2018
2.83
48
<1
3.184j
3.36
18
<0.05
0.342j
0.794j
0.25
1.41
<1
9.4 B2
<0.2
0.747 S1
1.962 j,B2
<5
<1
<1
16
<1
<50
<1
0.845j
<1
<1
<10
MW-12D
Transition Zone
11/07/2018
0.582j
149
<1
<5
3.39
28
0.021j
0.37j
0.371j
0.241
1.42
<1
9.25
0.083j
0.68
14
2.501j
<1
<1
15
<1
<50
<1
0.889j
<1
0.76j
9.654j
MW-12S
Saprolite
01/16/2018
3.88
3010
1.52
.856
<1
1.29
0.024
2.19 B3
4.05 B1
<0.2
2.09
15
23
<1
<1
1.46
<1
1880 S1
MW-12S
Saprolite
04/02/2018
1.06
809
<1
<5
0.577
128
<0.05
0.205j
0.805j
0.047
1.62
<1
4.69
0.091j
1.05
24
6
<1
0.875j
10
<1
<50
<1
<1
0.624j
<1
517
MW-12S
Saprolite
07/18/2018
3.51
510
0.383j
3.692j
0.91
101
<0.05
0.332j
1.4
0.135
2.06
<1
4.11 B2
<0.2
1.5 S1
126 B2
41
<1
0.588j
16
<1
<50
<1
0.471j
0.724j
<1
346
MW-12S
Saprolite
11/07/2018
2.57
776
0.597j
<5
0.861
153
0.023j
0.272j
0.837j
0.214
2.23
<
3.9
<0.2
2.09
94
47
<1
0.446j
13
<1
<50
<1
0.666j
0.925j
41
323
MW-13BR
Bedrock
01/16/2018
<1
1850
<1
<5
11.3
369
<0.05
2.34
3.52
<0.02
4.14 B3
<1
16.2 BI
<0.2
0.408
<5
<5
<1
<1
21
<1
<50
<1
<1
5.78
<1
1430 S1
MW-13BR
Bedrock
04/04/2018
0.945j
1640
<1
3.056j
12.5
321
<0.05
2.02
2.7
<0.02
4.24
<1
16.4
<0.2
1 0.363
3.817j
3.134j
0.384j
<1
20
<1
<50
<1
0.357j
4.41
<1
1290
MW-13BR
Bedrock
07/18/2018
2.86
2080
1.27
5 B2
303
<0.05
2.06
.87
<0.01
<1
16.3 B2
<0.2
1.97 S1
9 B2
4.952j
<1
<1
17
<1
<1
1
3.97
]JILI
488
MW-13BR
Bedrock
11/08/2018
0.635j
675
<1
2.316j
12.2
260
0.02j
2.11
<1
<0.01
4.34
<1
15.9
<0.2
0.282j
<5
2.587j
<1
<1
16
<1
<50
<1
<1
4.54
<1
554
MW-14BR
Bedrock
01/22/2018
1.52
30 B2
<1
47
2.49
57
<0.05
5.96
<1
0.126
8.63
<1
49.1 B3
<0.2
2.23
<5
<5
<1
<1
19
<1
<50
<1
<1
<1
1.01
<10
MW-14BR
Bedrock
04/04/2018
2.09
45 S1
<1
7
2.72
55
<0.05
3.99
<1
0.4
3.9
<1
37
<0.2
2.4
2.407 j
1.9581
<1
0.575 j
17
<1
<50
<1
<1
<1
0.856 j
<10
MW-14BR
Bedrock
07/18/2018
3.23
104
<1
9 B2
2.71
119
<0.05
4.37
0.42j
0.364
4.11
<1
38.8 B2
<0.2
2.55 Si
3.146 j,B2
4.119j
<1
0.482j
15
<1
<50
<1
<1
<1
0.566j
<10
MW-14BR
Bedrock
11/07/2018
2.65
178
<1
9
2.49
114
0.019j
4.18
<1
0.427
3.91
<1
40.6
<0.2
2.74
2.656j
3.511j
<1
0.518j
13
<1
<50
<1
<1
<1
1.22
<10
MW-16BR
Bedrock
01/22/2018
<1
1290
<1
<5
4.4
366
<0.05
25.7
<1
0.014
3.24
<1
24.4 B3
<0.2
<0.3
<5
5
<1
<1
13
<1
<50
<1
<1
<1
<1
894
MW-16BR
Bedrock
04/03/2018
0.508j
1650
<1
2.401j
4.55
346
<0.05
23
<1
0.033
3.36
<1
24.5
<0.2
0.234j
2.671j
3.603j
<1
0.452j
14
<1
30.726j
<1
<1
<1
<1
612
MW-16BR
Bedrock
07/18/2018
0.789j
1950
<1
3.388j
4.21
306
<0.05
25.5
<1
0.0067j
3.3
<1
24.3 B2
<0.2
0.222 j,S1
2.042 j,B2
4.318j
<1
0.388j
14
<1
25.176j
<1
<1
<1
<1
1530
MW-16BR
Bedrock
11/06/2018
0.613j
2400
<1
<5
4.51
319
<0.05
20.1
<1
0.007j
3.12
<1
21.9
<0.2
0.103j
3.136j
3.257j
<1
0.339j
14
<1
24.161j
<1
<1
<1
<1
1720
MW-16D
Transition Zone
01/22/2018
<1
47 B2
<1
<5
5.29
49
<0.05
5.64
<1
2.7
1.87
<1
9.63 B3
<0.2
0.677
<5
<5
<1
<1
<5
<1
<50
<1
<1
<1
<1
<10
MW-16D
Transition Zone
04/03/2018
<1
117
<1
1.672 j
5.2
10
<0.05
4.58
<1
3.3
1.82
0.547 j
10
<0.2
0.669
<5
2.442 j
<1
<1
3.386 j
<1
<50
<1
<1
<1
<1
<10
MW-16D
Transition Zone
07/18/2018
1.38
195
<1
3.187j
5.36
128
<0.05
5.49
<1
2.9
1.84
0.49j
9.88 B2
<0.2
0.823 SI
<5
4.063j
<1
<1
3.128j
<1
<50
<1
<1
<1
<1
<10
MW-16D
Transition Zone
11/06/2018
0.885j
156
<1
<5
5.14
173
<0.05
5.41
0.404j
3
1.77
<1
9.73
<0.2
0.761
7
1.882j
<1
<1
3.179j
<1
<50
<1
<1
<1
<1
<10
MW-16S
Alluvial
01/22/2018
<1
80
<1
<5
4.36
17
<0.05
<1
1.08
0.182
1.26
<1
12.1 B3
<0.2
<0.3
8
<5
<1
<1
107
<1
397
<1
<1
<1
<1
34
MW-16S
Alluvial
04/03/2018
<1
151
<1
<5
3.03
6
<0.05
0.197j
0.905j
2.2
1.08
<1
8.32
<0.2
0.175j
2.953j
2.009j
<1
<1
78
<1
200
<1
<1
<1
<1
<10
MW-16S
Alluvial
07/18/2018
1.3
657
<1
2.174j
2.72
23
<0.05
0.423j
1.51
2.6
1.33
<1
6.65 B2
<0.2
0.3 S1
7 B2
<5
<1
<1
75
<1
183
<1
<1
0.429j
<1
<10
MW-16S
Alluvial
11/06/2018
0.937j
5o
<1
<5
2.52
10
<0.05
0.261j
0.599j
0.432
1.29
<1
5.92
<0.2
0.144j
4.052j
4.201j
<1
<1
73
<1
105
<1
<1
<1
<1
<10
MW-18BR
Bedrock
01/15/2018
<1
343
<1
9
8.21
1510
<0.05
1.88
<1
<0.02
7.37
<1
22.5 B3
<0.2
<0.3
<5
<5
<1
<1
94
<1
<50
<1
<1
<1
<1
243
MW-18BR
Bedrock
04/04/2018
0.622j
430
<1
7
8.43
1420
<0.05
5.85
<1
<0.02
7.73
<1
25.2
<0.2
0.188j
<5
3.189j
<1
0.573j
97
<1
<50
<1
<1
<1
<1
327
MW-18BR
Bedrock
07/18/2018
0.502j
690
<1
6 B2
8.32
1300
<0.05
27.8
<1
<0.01
8.19
<1
36.7 B2
<0.2
0.398 S1
<5
3.495j
<1
1.74
90
<1
<50
<1
<1
<1
<1
603
MW-18BR
Bedrock
09/12/2018
<1
632
<1
3.49j
8.38
1320
<0.05
20.3
<1
<0.01
7.92
<1
33.7
<0.2
0.25j
<5
3.238j
<1
1.11
91
<1
<50
<1
<1
<1
<1
445
MW-18BR
Bedrock
11/06/2018
0.388j
625
<1
5
8.36
1380
0.017j
19.3
<1
<0.01
7.75
<1
32.8
<0.2
0.284j
2.331j
3.481j
<1
1.44
89
<1
<50
<1
<1
<1
<1
513
MW-18BR
Bedrock
12/05/2018
<1
491
<1
6
8.18
1360
<0.05
12.6
<1
<0.01
7.46
<1
28.8
<0.2
<0.3
2.298 j,B2
3.374j
<1
0.826j
92
<1
<50
<1
<1
<1
<1
421
MW-18D
Transition Zone
01/15/2018
<1
87 S1
<1
30
5.75 S1
7
0.08 S1
<1
<1
0.91
5.6
<1
28.3 B3
<0.2
1.51
8 S1
<5
<1
<1
<5
<1
<50
<1
<1
<1
<1
<10
MW-18D
Transition Zone
04/04/2018
2.05
118 SI
<1
8
5.63
7
0.06
0.802 j
0.743 j
0.92
5.5
0.397 j
28.8
<0.2
1.98
6 SI
2.567 j
<1
<1
3.212 j
<1
<50
<1
<1
<1
0.505 j
<10
MW-18D
Transition Zone
07/18/2018
1.56
28
<1
9 B2
6.15
3.055j
<0.05
0.698j
0.752j
0.864
5.28
0.336j
28 B2
0.114 j,S1
1.5 S1
18 B2
2.049j
<1
<1
3.474j
<1
<50
<1
<1
<1
<1
<10
MW-18D
Transition Zone
09/12/2018
0.741 j
7.779 j
<1
4.811 j
6.46
2.249 j
<0.05
0.669 j
0.57 j
0.87
5.3
0.401 j
29.1
<0.2
1.29
21
43
<1
<1
3.44 j
<1
<50
0.342 j
<1
<1
1.04
8.094 j
MW-18D
Transition Zone
11/06/2018
1.33
385
<1
7
6.03
26
0.03j
0.777j
0.55j
0.797
5.48
<1
28.3
<0.2
1.9
12
<5
<1
<1
3.948j
<1
<50
<1
<1
<1
0.531j
<10
MW-18D
Transition Zone
12/05/2018
0.816 j
144
<1
7
5.92
4.426 j
<0.05
0.668 j
0.634 j
0.857
5.06
<1
28.1
<0.2
1.36
15 B2
1.812 j
<1
<1
3.862 j
<1
<50
<1
<1
<1
0.482 j
<10
MW-19BR
Bedrock
01/15/2018
<1
1300
<1
<5
35.5
1370
<0.05
<1
<1
<0.02
7.17
<1
27.2 B3
<0.2 B3
<0.3
<5
<5
<1
<1
59
<1
<50
<1
<1
<1
<1
1310
MW-19BR
Bedrock
04/04/2018
<1
1340
<1
3.394 j
33.5
1330
<0.05
0.563 j
0.408 j
<0.02
7.15
<1
27.7
<0.2
0.178 j
<5
5
<1
0.358 j
58
<1
<50
<1
<1
0.37 j
<1
1280
MW-19BR
Bedrock
07/18/2018
0.917j
1360
<1
6 B2
35.8
1340
<0.05
0.594j
0.413j
0.0039j
7.37
<1
28.2 B2
<0.2
0.214j,S1
4.007j,B2
6
<1
<1
61
<1
<50
<1
<1
0.389j
<1
1340
MW-19BR
Bedrock
11/06/2018
<1
1330
<1
2.549 j
33.6
1360
<0.05
0.797 j
<1
<0.01
7.13
<1
28
<0.2
0.19 j
<5
3.5663
<1
0.345 j
60
<1
<50
<1
<1
0.376 j
<1
1370
MW-19D
Transition Zone
01/15/2018
<1
1770
1.76
7
34.7
1040
<0.05
<1
<1
<0.02
6.99
<1
27.6 B3
<0.2
<0.3
6
<5
<1
<1
60
<1
<50
<1
<1
<1
<1
1240
MW-19D
Transition Zone
04/04/2018
0.622j
2140
4.15
4.139j
32.8
941
<0.05
0.382j
0.565j
<0.02
6.8
<1
28.5
0.091j
0.263j
<5
2.773j
<1
<1
59
<1
<50
<1
<1
0.75j
<1
1200
MW-19D
Transition Zone
07/18/2018
0.643j
1470
0.478j
6 B2
33.9
981
<0.05
0.434j
0.589j
<0.01
6.98
<1
28.8 B2
0.084 j,S1
0.184j,S1
2.234j,B2
3.02j
<1
<1
58
<1
<50
<1
<1
0.696j
<1
1110
MW-19D
Transition Zone
1 11/06/2018
0.478j
2470
5.98
1 2.935j
32.9
1190
0.017j
0.744j
0.455j
<0.01
7.3
<1
29.2
<0.2
0.281j
3.13j
2.799j
<1
<1
59
<1
1 <50
<1
<1
0.713j
<1
1120
Prepared by: BER Checked by: JAW
Page 8 of 9

TABLE 3-3
2018 COMPREHENSIVE GROUNDWATER QUALITY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Analytical Parameter
INORGANIC PARAMETERS (DISSOLVED CONCENTRATION WITH FILTER SIZE)
RADIONUCLIDES
OTHER PARAMETERS
Lead
(0.45u)
ug/L
Lithium
(0.45u)
ug/L
Manganese
(0.45u)
ug/L
Mercury
(0.45u)
ug/L
Molybdenum
(0.45u)
ug/L
Nickel
(0.45u)
ug/L
Phosphorus
(0.45u)
mg/L
Selenium
(0.45u)
ug/L
Silver
(0.45u)
ug/L
Strontium
(0.45u)
ug/L
Thallium
(0.45u)
ug/L
Vanadium
(0.45u)
ug/L
Zinc
(0.45u)
ug/L
Radium-226
pCi/L
Radium-228
pCi/L
Total Radium
pCi/L
Uranium-238
ug/mL
Total Uranium
ug/mL
Carbonate
Alkalinity
mg/L
Fluoride
mg/L
Phosphorus
mg/L
Reporting Units
15A NCAC 02L Standard
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
5^
NE
0.03^
NE
2
NE
Provisional Background Threshold Values (Surficial Unit)
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
4
NE
0.000367
5
NE
NE
Provisional Background Threshold Values (Transition Zone Unit)
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
9
NE
0.001
5
NE
NE
Provisional Background Threshold Values (Bedrock Unit)
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
NE
7.6
NE
0.00203
5
NE
NE
Sample ID
Well Screen
Location
Sample
Collection Date
Analytical Results
MW-10BR
Bedrock
07/18/2018
<1
4.011j
36
<0.05
0.579j
1.75
0.19
<1
NA
203
<0.2
1.84 B3
50
5.71
0.307 U
6.017
NA
0.0000671j
<5
0.37
0.21
MW-10BR
Bedrock
11/06/2018
<1
3.597j
31
<0.05
0.644j
1.37
0.22
<1
NA
201
<0.2
2.05
22
1.54
-0.0199 U
1.5201
<0.0002
<0.0002
<5
0.35
0.23
MW-12D
Transition Zone
01/16/2018
<1
<5
17
<0.05
<1
<1
<0.05
<1
NA
84
<0.2
0.606
<5
2.74
<1
2.74
NA
0.000102j
<5
0.1
<0.05
MW-12D
Transition Zone
04/02/2018
<1
1.829j
17
<0.06
0.388j
0.882j
<0.05
<1
NA
91
<0.2
0.523
3.138j
0.421
0.246 U
0.667
NA
0.000108j
<5
0.0968j
0.053
MW-12D
Transition Zone
07/18/2018
<1
<5
14
<0.05
0.354j
0.779j
<0.05
<1
NA
89
0.106 j,B3
0.605 B3
1.986j
16.1
-0.155 U
15.945
NA
0.0000928j
<5
0.0788j
<0.05
MW-12D
Transition Zone
11/07/2018
<1
<5
21
<0.05
0.31j
0.654j
0.053
<1
NA
90
<0.2
0.641
13
3.61
0.245 U
3.855
0.000107j
0.000107j
<5
<0.1
0.056
MW-12S
Saprolite
01/16/2018
<0.05
<0.05
1
NA
18
<0.2
0.69
NA JILO.0000804j
<0.05
MW-12S
Saprolite
04/02/2018
<1
1.712j
125
<0.05
0.194j
0.465j
<0.05
<1
NA
12
<0.2
0.661
22
0.153 U
0.441 U
0.594
NA
0.0000866j
<5
0.0782j
<0.05
MW-12S
Saprolite
07/18/2018
<1
<5
146
<0.05
0.297 j
1.07
<0.05
<1
NA
21
<0.2
1.12 B3
92
0.407
-0.0751 U
0.3319
NA
<0.0002
<5
0.0703 j
<0.05
MW-12S
Saprolite
11/07/2018
<1
<5
53
<0.05
.27j
0.953j
<0.05
<1
NA
17
<0.2
1.59
77
0.54
0.22 U
0.0000899j
0.0000899j
<5
0.0493j
<0.05
MW-13BR
Bedrock
01/16/2018
<1
<5
337
<0.05
2.06
1.22
0.059
<1
NA
329
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
0.15
0.06951
MW-13BR
Bedrock
04/04/2018
<1
<5
296
<0.05
2.04
1.46
0.08
<1
NA
333
<0.2
0.122j
3.709j
NA
NA
NA
NA
NA
<5
0.12
0.089
MW-13BR
Bedrock
07/18/2018
.044j
1.92
0.409j
0.058
NA
326
<0.2
0.16 j,B3
2.724j
kp.11
0.073
MW-13BR
Bedrock
11/08/2018
<1
<5
257
<0.05
1.63
<1
0.083
<1
NA
340
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
0.0772j
0.073
MW-14BR
Bedrock
01/22/2018
<1
39
51
<0.05
5.78
<1
0.36
<1
NA
218
<0.2
2.23
<5
NA
NA
NA
NA
NA
<5
0.36
0.35
MW-14BR
Bedrock
04/04/2018
<1
6
43
<0.05
3.78
<1
0.3
<1
NA
161
0.12 j
2.22
3.693 j
NA
NA
NA
NA
NA
<5
0.32
0.3
MW-14BR
Bedrock
07/18/2018
<1
7
70
<0.05
3.69
<1
0.31
<1
NA
155
<0.2
2.23 B3
3.077 j
NA
NA
NA
NA
NA
<5
0.3
0.3
MW-14BR
Bedrock
11/07/2018
<1
8
57
<0.0555
3.38
<1
0.38
<1
NA
159
<0.2
2.46
2.701j
NA
NA
NA
NA
NA
<5
0.25
0.37
MW-16BR
Bedrock
01/22/2018
<1
<5
265
<0.05
34.1
<1
<0.05
<1
NA
124
<0.2
<0.3
<5
0.125 U
-0.0772 U
0.0478
NA
0.0000771j
<5
0.36
<0.05
MW-16BR
Bedrock
04/03/2018
<1
2.007j
268
<0.05
35.2
<1
<0.05
<1
NA
125
<0.2
<0.3
<5
0.378
0.112 U
0.49
NA
0.000105j
<5
0.33
<0.05
MW-16BR
Bedrock
07/18/2018
<1
<5
304
<0.05
23.2
<1
<0.05
<1
NA
131
<0.2
0.146 j,B3
<5
0.0518 U
0.126 U
0.1778
NA
0.000114j
<5
0.4
<0.05
MW-16BR
Bedrock
11/06/2018
<1
<5
351
<0.05
20.6
<1
<0.05
<1
NA
137
<0.2
0.158j
<5
0.0388 U
0.0964 U
0.1352
0.000151j
0.000151j
<5
0.32
<0.05
MW-16D
Transition Zone
01/22/2018
<1
<5
<5
<0.05
5.15
<1
0.11
<1
NA
178
<0.2
0.611
<5
0.462
0.368 U
0.83
NA
0.000416
<5
0.24
0.11
MW-16D
Transition Zone
04/03/2018
<1
2.185j
<5
<0.05
4.61
<1
0.13
0.577j
NA
165
0.181j
0.567
1.87j
4.17
0.174 U
4.344
NA
0.000281
<5
0.21
0.13
MW-16D
Transition Zone
07/18/2018
<1
<5
2.952j
<0.05
4.74
<1
0.11
0.447j
NA
169
<0.2
0.57 B3
<5
0.903
0.357 U
1.26
NA
0.000276
<5
0.22
0.12
MW-16D
Transition Zone
11/06/2018
<1
<5
3.044 j
<0.05
5.09
<1
0.13
0.44 j
NA
176
<0.2
0.704
<5
3.45
0.19 U
3.64
0.000289
0.000289
<5
0.2
0.13
MW-16S
Alluvial
01/22/2018
<1
<5
21
<0.05
<1
<1
<0.05
<1
NA
214
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
<0.1
<0.05
MW-16S
Alluvial
04/03/2018
<1
<5
7
<0.05
0.215 j
0.956 j
<0.05
<1
NA
147
0.101 j
<0.3
2.374 j
NA
NA
NA
NA
NA
<5
<0.1
<0.05
MW-16S
Alluvial
07/18/2018
<1
<5
36
<0.05
0.233j
1.24
<0.05
<1
NA
137
<0.2
0.126 j, B3
3.94j
NA
NA
NA
NA
NA
<5
0.0594j
<0.05
MW-16S
Alluvial
11/06/2018
<1
<5
10
<0.05
0.241j
0.552j
<0.05
<1
NA
128
<0.2
0.171j
3.428j
NA
NA
NA
NA
NA
<5
<0.5
<0.05
MW-18BR
Bedrock
01/15/2018
<1
8
1400
<0.05
1.61
<1
<0.05
<1
NA
464
<0.2 B2
<0.3
<5
NA
NA
NA
NA
NA
<5
0.22
<0.05
MW-18BR
Bedrock
04/04/2018
<1
6
1430
<0.05
3.62
<1
<0.05
<1
NA
471
0.085j
<0.3
2.376j
NA
NA
NA
NA
NA
<5
0.19
<0.05
MW-18BR
Bedrock
07/18/2018
<1
4.578j
1340
<0.05
16.9
<1
<0.05
<1
NA
447
<0.2
0.166 j, B3
<5
NA
NA
NA
NA
NA
<5
0.19
<0.05
MW-18BR
Bedrock
09/12/2018
<1
6
1340
<0.05
8.84
<1
<0.05
<1
NA
448
0.148j
0.253j
2.023j
0.371 U
0.275 U
0.646
0.00601
0.00601
<5
0.18
<0.05
MW-18BR
Bedrock
11/06/2018
<1
6
1360
<0.05
14.5
<1
<0.05
<1
NA
442
<0.2
<0.3
1.775j
NA
NA
NA
NA
NA
<5
0.16
<0.05
MW-18BR
Bedrock
12/05/2018
<1
4.631j
1390
<0.05
8.7
<1
<0.05
<1
NA
457
<0.2
<0.3
<5
1.64
0.737
2.377
0.00485
0.00485
<5
0.14
<0.05
MW-18D
Transition Zone
01/15/2018
<1
9
<5
<0.05
<1
<1
0.17
<1
NA
162
<0.2 B2
1.29
21
NA
NA
NA
NA
NA
<5
0.19
0.17
MW-18D
Transition Zone
04/04/2018
<1
6
2.529j
<0.05
0.677j
0.567j
0.18
0.413j
NA
159
<0.2
1.22
23
NA
NA
NA
NA
NA
<5
0.17
0.16
MW-18D
Transition Zone
07/18/2018
<1
6
2.371j
<0.05
0.632j
0.537j
0.18
<1
NA
156
<0.2
1.13 B3
23
NA
NA
NA
NA
NA
<5
0.16
0.17
MW-18D
Transition Zone
09/12/2018
<1
6
1.783j
<0.05
0.726j
0.664j
0.17
<1
NA
157
<0.2
1.49
25
1.41
0.102 U
1.512
0.000224
0.000224
<5
0.16
0.17
MW-18D
Transition Zone
11/06/2018
<1
7
20
<0.05
0.773j
0.356j
0.17
<1
NA
162
<0.2
1.34
15
NA
NA
NA
NA
NA
<5
0.15
0.18
MW-18D
Transition Zone
12/05/2018
<1
5
3.403j
<0.05
0.645j
0.489j
0.17
<1
NA
151
<0.2
1.14
13
2.87
-0.0417 U
2.8283
0.000204
0.000204
<5
0.11
0.16
MW-19BR
Bedrock
01/15/2018
<1
8
1330
<0.05
<1
<1
<0.05
<1
NA
434
<0.2 B2
<0.3
<5
NA
NA
NA
NA
NA
<5
<0.5
<0.05
MW-19BR
Bedrock
04/04/2018
<1
<5
1310
<0.05
0.657j
0.442j
<0.05
<1
NA
424
<0.2
<0.3
<5
NA
NA
NA
NA
NA
<5
0.2805j
<0.05
MW-19BR
Bedrock
07/18/2018
<1
2.819j
1360
<0.05
0.696j
0.439j
<0.05
<1
NA
437
<0.2
0.156 j,B3
1.711j
NA
NA
NA
NA
NA
<5
0.1894j
<0.05
MW-19BR
Bedrock
11/06/2018
<1
2.326j
1390
<0.05
0.828j
<1
<0.05
<1
NA
438
0.124j
0.165j
1.867j
NA
NA
NA
NA
NA
<5
0.236j
<0.05
MW-19D
Transition Zone
01/15/2018
<1
6
944
<0.05
<1
<1
<0.05
<1
NA
366
<0.2 B2
<0.3
<5
NA
NA
NA
NA
NA
<5
<0.5
0.12
MW-19D
Transition Zone
04/04/2018
<1
2.12j
946
<0.05
0.355j
0.639j
<0.05
<1
NA
358
<0.2
0.114j
2.288j
NA
NA
NA
NA
NA
<5
0.2815j
0.081
MW-19D
Transition Zone
07/18/2018
<1
2.991j
970
<0.05
0.41j
0.591j
<0.05
<1
NA
353
<0.2
0.151 j,B3
2.631j
NA
NA
NA
NA
NA
<5
0.1886j
<0.05
MW-19D
Transition Zone
11/06/2018
<1
3.004j
1030
<0.05
0.419j
0.554j
<0.05
<1
NA
363
<0.2
0.199j
3.801j
NA
NA
NA
NA
NA
<5
0.1626j
0.13
Prepared by: BER Checked by: JAW
Page 9 of 9

TABLE 3-4
DATA QUALIFIERS AND ACRONYMS
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
COLOR NOTES
Bold highlighted concentration indicates exceedance of the 15A NCAC 02L .0202 Standard or the IMAC. (Effective date for 15A NCAC 02L .0202
Standard and IMAC is April 1, 2013)
Turbidity of Sample >_ 10 NTUs
Provisional Background Threshold Values updated with Background Results through October 2017.
Analytical data review has not been completed for this dataset.
ABBREVIATION NOTES
BGS - below ground surface
BOD - Biologic Oxygen Demand
CB - Compliance Boundary
COD - Chemical Oxygen Demand
Deg C - Degrees Celsius
DMAs - dimethylarsinic acid
DUP - Duplicate
Eh - Redox Potential
ft - Feet
GPM - gallons per minute
IMAC - Interim Maximum Allowable Concentrations. From the 15A NCAC 02L Standard, Appendix 1, April, 1, 2013.
MDC - Minimum Detectable Concentration
McSe - Methylseleninic acid
mg/kg - milligrams per kilogram
mg/L - milligrams per liter
mg-N/L - Milligram nitrogen per liter
MMAs - mono methylarsonic acid
mV - millivolts
NA - Not available or Not Applicable
NE - Not established
NM - Not measured
NTUs - Nephelometric Turbidity Units
pCi/L - picocuries per liter
PSRG - Primary Soil Remediation Goals
RL - Reporting Limit
SeCN - selnocynante
SeMe (IV) - Selenomethionine
SPLP - Synthetic Precipitation Leaching Procedure
S.U. - Standard Units
TCLP - Toxicity Characteristic Leaching Procedure
ug/L - micrograms per liter
ug/mL - microgram per milliliter
umhos/cm - micromhos per centimenter
Well Locations referenced to NAD83 and elevations referenced to NAVD88
LABORATORY FLAGS
< - concentration not detected at or above the adjusted reporting limit.
A Federal MCL.
* Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013.
** - 15A NCAC 02B .0218 Standards for Class WS-V Waters only applicable to SW-REF1 and S-06 locations (for turbidity, 25 NTUs).
lg - Result confirmed by second analysis performed out of hold.
2g - The concentration in the Blank QC is less than the reporting limit but greater than 1/2 the reporting limit.
B - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample is less than 1OX the concentration
in the method blank. Analyte concentration in sample could be due to blank contamination.
Bl - Target analyte detected in method blank at or above the reporting limit. Target analyte concentration in sample was greater than 1OX the
concentration in the method blank. Anal to concentration in sample is not affected by blank contamination.
Page 1 of 2

TABLE 3-4
DATA QUALIFIERS AND ACRONYMS
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
LABORATORY FLAGS (CONTINUED)
B2 - Target analyte was detected in blank(s) at a concentration greater than 1/2 the reporting limit but less than the reporting limit. Analyte
concentration in sample is valid and may be used for compliance purposes.
B3 - Target analyte was detected in Continuing Calibration Blank(s) at a concentration greater than 1/2 the reporting limit but less than the reporting
limit. Analyte concentration in sample is valid and may be used for compliance purposes.
134 - Target analyte was detected in Continuing Calibration Blank(s) at or above the reporting limit.
B5 - Target analyte was present in blank(s) above the method detection limit but less than the reporting limit. Data is valid for compliance purposes.
B6 - Target analyte was detected in Continuing Calibration Blank(s) at a concentration greater than the reporting limit.
CH - The continuing calibration for this compound is outside of Pace Analytical acceptance limits. The results may be biased high.
CL - The continuing calibration for this compound is outside of Pace Analytical acceptance limits. The results may be biased low.
CR - The dissolved metal result was greater than the total metal result for this element. Results were confirmed by reanalysis.
CU - The continuing calibration for this compound is outside of Pace Analytical acceptance limits. Analyte presence below reporting limits in associated
samples. Results unaffected by high bias.
D3 - Sample was diluted due to the presence of high levels of non -target analytes or other matrix interference.
D4 - Sample was diluted due to the presence of high levels of target analytes.
D6 - The precision between the sample and sample duplicate exceeded laboratory control limits.
E - Analyte concentration exceeded the calibration range. The reported result is estimated.
H - Sample analyzed past the recommended holding time.
H1 - Analysis conducted outside the EPA method holding time.
H2 - Extraction of preparation conducted outside EPA method holding time.
H3 - Sample was received or analysis requested beyond the recognized method holding time.
H6 - Analysis initiated outside of the 15 minute EPA required holding time.
HS - Results are from sample aliquot taken from VOA vial with headspace (air bubble greater than 6 mm diameter).
j - Estimated concentration above the adjusted method detection limit and below the adjusted reporting limit.
Ll - Analyte recovery in the laboratory control sample (LCS) was above quality control (QC) limits. Results may be biased high.
L2 - Analyte recovery in the laboratory control sample (LCS) was below QC limits. Results for this analyte in associated samples may be biased low.
L3 - Analyte recovery in the laboratory control sample (LCS) exceeded quality control (QC) limits. Analyte presence below reporting limits in
associated samples. Results unaffected by high bias.
M - Matrix spike / matrix spike dup failure.
M1 - Matrix spike recovery was high: the associated Laboratory Control Spike (LCS) was acceptable.
M2 - Matrix spike recovery was Low: the associated Laboratory Control Spike (LCS) was acceptable.
M4 - The spike recovery value was unusable since the analyte concentration in the sample was disproportionate to the spike level.
M6 - Matrix spike and Matrix spike duplicate recovery not evaluated against control limits due to sample dilution.
N2 - The lab does not hold accreditation for this parameter.
ND - Not detected
P2 - Re -extraction or re -analysis could not be performed due to insufficient sample amount.
P4 - Sample field preservation does not meet EPA or method recommendations for this analysis.
P8 - Analyte was detected in the method blank. All associated samples had concentrations of at least ten times greater than the blank or were below
the reporting limit.
PM - The data are unusable (analyte may or may not be present). Resampling and reanalysis is necessary for verification. Manual review of raw data is
recommended in order to determine if the defect impacts data use.
RO - The data are unusable. The sample results are rejected due to serious deficiencies in meeting QC criteria. The analyte may or may not be present
in the sample.
RI - Relative Percent Difference (RPD) value was outside control limits.
S - Associated calibration check did not meet specified criteria.
S1 - Data review findings indicate result may be unreliable. Use with caution.
U - Analyte was analyzed for, but not detected above the MDC.
Page 2 of 2

TABLE 3-5
GEOMETRIC MEAN OF COIs - 2018 QUARTERLY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Analytical Parameter
SELECTED CONSTITUENTS OF INTEREST (COIs)
Boron
Strontium
Total
Dissolved
Solids
Cobalt
Manganese
Molybdenum
Reporting Units
Ng/L
Ng/L
mg/L
Ng/L
Ng/L
Ng/L
15A NCAC 02L Standard
Zo
NE
529
1*
50
NE
Background Threshold Values (Surficial Zone)
50
25
85
1.02
253
3.15
Background Threshold Values (Transition Zone)
50
=
430
1
1
ZQ$
1
Background Threshold Values (Bedrock)
50
418
340
1.19
544
13.1
Sample ID
Well Screen Location
Location Description
Sample
Collection Date
Analytical Results
ABMW-01
Ash Pore Water
Within ash basin
Geomean
5072
2150
352
3.6
795
239
ABMW-02
Ash Pore Water
Within ash basin
Geomean
8487
809
377
1.0
39.4
1345
ABMW-02BR
Bedrock
Beneath ash basin
Geomean
39.7
1122
335
1.0
231
18.7
ABMW-02BRL
Bedrock
Beneath ash basin
Geomean
50.0
2217
285
1.0
345
2.4
ABMW-03
Ash Pore Water
Within ash basin
Geomean
1962
1507
315
1.0
657
31.3
ABMW-03S
Saprolite
Beneath ash basin
Geomean
131
77.2
95
1_6
296
0.32
ABMW-04
Ash Pore Water
Within ash basin
Geomean
5900
3050
530
2.4
2190
320
ABMW-04BR
Bedrock
Beneath ash basin
Geomean
37.3
2004
312
1.0
460
7.8
ABMW-04D
Transition Zone
Beneath ash basin
Geomean
3236
1689
521
L2
6323
9.2
ABMW-04X
Ash Pore Water
Within ash basin
Geomean
5290
2310
430
0.44
1390
15
BG-01
Bedrock
Background well
Geomean
50.0
174
111
1.0
8.4
1.0
BG-02
Transition Zone
Background well
Geomean
50.0
290
299
1.0
82.3
0.76
CW-01
Transition Zone
Sidegradient of ash basin, outside of compliance boundary
Geomean
50.0
62.2
117
1.0
7.4
0.48
CW-01D
Bedrock
Sidegradient of ash basin, outside of compliance boundary
Geomean
50.0
184
204
1.0
17.2
22.3
CW-02
Transition Zone
Downgradient of ash basin, immediately inside of compliance boundary
Geomean
216
137
1.0
116
1.0
CW-02D
Bedrock
Downgradient of ash basin, immediately inside of compliance boundary
Geomean
272
370
310
0.90
98.1
2.2
CW-03
Transition Zone
Downgradient of ash basin, immediately inside of compliance boundary
Geomean
50.0
306
355
1.0
14
0.47
CW-04
Bedrock
Downgradient of ash basin, immediately inside of compliance boundary
Geomean
50.0
143
157
1.0
4.4
0.46
CW-05
Bedrock
Sidegradient of ash basin, inside compliance boundary
Geomean
50.0
167
277
1.0
zo
1.0
CW-06
Bedrock
Downgradient of ash basin, outside of compliance boundary
Geomean
50.0
329
492
0.75
1371
2.9
MW-02
Bedrock
Downgradient of ash basin, inside of compliance boundary
Geomean
50.0
220
200
�8
1310
1.2
MW-03
Saprolite
Downgradient of ash basin, inside of compliance boundary
Geomean
1089
319
195
1.0
1249
0.36
MW-03BR
Bedrock
Downgradient of ash basin, immediately inside of compliance boundary
Geomean
50.0
397
¢j¢
1.0
605
1.1
MW-04
Bedrock
Sidegradient of ash basin
Geomean
50.0
121
210
1 1.0
105
2.9
MW-05BR
Bedrock
Sidegradient of ash basin, inside compliance boundary
Geomean
50.0
228
404
0.87
Im
1.0
Page 1 of 2

TABLE 3-5
GEOMETRIC MEAN OF COIs - 2018 QUARTERLY DATA
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Analytical Parameter
SELECTED CONSTITUENTS OF INTEREST (COIs)
Boron
Strontium
Total
Dissolved
Solids
Cobalt
Manganese
Molybdenum
Reporting Units
Ng/L
pg/L
mg/L
Ng/L
pg/L
pg/L
15A NCAC 02L Standard
Zo
NE
529
1*
50
NE
Background Threshold Values (Surficial Zone)
50
25
85
1.02
253
3.15
Background Threshold Values (Transition Zone)
50
=
430
1
1
2M
i
Background Threshold Values (Bedrock)
50
418
340
1.19
544
13.1
Sample ID
Well Screen Location
Location Description
Sample
Collection Date
Analytical Results
MW-08BR
Bedrock
Side gradient of ash basin, outside of compliance boundary
Geomean
50.0
360
439
0.61
224
2.5
MW-09BRL
Bedrock
Sidegradient of ash basin, outside of compliance boundary
Geomean
50.0
203
300
1.0
491
4_6
MW-10BR
Bedrock
Upgradient of ash basin
Geomean
50.0
202
297
1.0
43.1
0.69
MW-12D
Transition Zone
Background well
Geomean
50.0
90.0
88
1.0
21.7
0.53
MW-12S
Saprolite
Background well
Geomean
50.0
21.0
52
0.67
101
0.33
MW-13BR
Bedrock
Background well
Geomean
50.0
319
280
4_7
260
2_I
MW-14BR
Bedrock
Background well
Geomean
50.0
173
191
1.0
80.8
} ¢
MW-16BR
Bedrock
Downgradient of ash basin, outside of compliance boundary
Geomean
29.5
137
175
1.0
333
23.5
MW-16D
Transition Zone
Downgradient of ash basin, outside of compliance boundary
Geomean
50.0
172
140
1.0
57.4
5.3
MW-16S
Saprolite
Downgradient of ash basin, outside of compliance boundary
Geomean
187
152
76
1.0
12.4
0.38
MW-18BR
Bedrock
Sidegradient of ash basin, outside of compliance boundary
Geomean
50.0
9;z$
400
1.0
1380
10.7
MW-18D
Transition Zone
Sidegradient of ash basin, outside of compliance boundary
Geomean
50.0
161
265
1.0
5.8
0.76
MW-19BR
Bedrock
Sidegradient of ash basin, outside of compliance boundary
Geomean
50.0
9¢
0.50
1350
0.72
MW-19D
Transition Zone
Side gradient of ash basin, outside of compliance boundary
Geomean
50.0
363
513
0.83
1034
0.59
Prepared by: HEG Checked by: ENK
Notes:
Geometric means were calculated for wells with four or more valid sample results. Sample results were excluded if turbidity>10, pH>10 (for antimony, arsenic, chromium (total), molybdenum, selenium and vanadium only) and
unusable data (RO qualified). For wells with datasets containing fewer than four valid results, the most recent valid sample was used. All data is from 2018.
Bold, underlined, italicized text - Constituent concentration exceeds applicable comparison criteria.
0 - Constituent concentration shown is most recent valid sample available due to insufficient dataset for geomean calculation.
* - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013.
< - concentration not detected at or above the adjusted reporting limit.
pg/L - Micrograms per liter
mg/L - Milligrams per liter
NE - Not Established
S.U. - Standard Unit
Page 2 of 2

TABLE 3-6
CONSTITUENTS OF INTEREST EVALUATION
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
Constituent of Interest
(2019 IMP Parameters)
2L Criterion
Groundwater Zone Statistically Derived
Background Value'
Maximum 2018
Geomean
Concentration
Near or Outside of Compliance
Boundary (mg/L)
Exceedance
Ratio
Number of
Wells Above
Criterion Near
or Outside of
Compliance
Boundary
Rationale for Exclusion from Mapping in Annual Report
Constituents with 2L Criteria
Shallow: 1
<1.0
0
0
No concentrations greater than criterion.
Arsenic
10 (pg/L)
Transition Zone: 1
<1.0
0
0
No concentrations greater than criterion.
Bedrock: 1
<1.0
0
0
No concentrations greater than criterion.
Shallow: 19
81.41
0.12
0
No concentrations greater than criterion.
Barium
700 (pg/L)
Transition Zone: 78.3
107.80
0.15
0
No concentrations greater than criterion.
Bedrock: 97
43.40
0.06
0
No concentrations greater than criterion.
Shallow: 50
187.18
0.27
0
Figure 3-11
Boron
700 (pg/L)
Transition Zone: 50
858.40
1.2
1
Figure 3-12
Bedrock: 50
271.90
0.4
0
Figure 3-13
Shallow: 3.23
<1.0
0
0
No concentrations greater than criterion.
Chromium (Total)
10 (pg/L)
Transition Zone: 6
<1.0
0
0
No concentrations greater than criterion.
Bedrock: 7
5
0.5
0
No concentrations greater than criterion.
Shallow: 0.088
0.03
0
0
No concentrations greater than criterion.
Chromium (Hexavalent)
10 (pg/L)
Transition Zone: 1.26
0.1
0
0
No concentrations greater than criterion.
Bedrock: 0.4
0.3
0.03
0
No concentrations greater than criterion.
Shallow: 385
141.14
0.37
0
No concentrations greater than criterion.
Iron
300 (pg/L)
Transition Zone: 1319
152.7
0.1
0
No concentrations greater than criterion.
Bedrock: 2550
1776.6
0.7
0
No concentrations greater than criterion.
Shallow: 253
12.38
0.05
0
No concentrations greater than criterion.
Manganese
50 (pg/L)
Transition Zone: 298
115.6
0.4
0
No concentrations greater than criterion.
Bedrock: 544
1371.5
2.52
2
Occurs in high and variable concentrations in background - does not exhibit a discernable plume. Variably reactive COI.
Shallow: 1.6
10.83
0.04
0
No concentrations greater than criterion.
Sulfate
250 (mg/1)
Transition Zone: 7.5
40
0.16
0
No concentrations greater than criterion.
Bedrock: 18
70.4
0.28
0
No concentrations greater than criterion.
Shallow: 85
75.59
0.15
0
No concentrations greater than criterion.
Total Dissolved Solids
500 (mg/1)
Transition Zone: 430
139.8
0.28
0
No concentrations greater than criterion.
Bedrock: 340
616
1.23
1
Does not exhibit a discernable plume.
Shallow: 4
0.00
0.00
0
No concentrations greater than criterion.
Total Radium
5 (pCi/L)
Transition Zone: 9
2.95
0.33
0
No concentrations greater than criterion.
Bedrock: 7.6
118.76
15.63
1
Does not exhibit a discernable plume.
Shallow: 0.000367
0.00
0.00
1 0
0-co ncentrations greater than criterion.
Total Uranium
0.3 (pg/m L)
Transition Zone: 0.001
0.00
0.01
0
No concentrations greater than criterion.
Bedrock: 0.00203
0.00
0.08
0
No concentrations greater than criterion.
Constituents with IMAC Criteria
Shallow: 1.02
1
0.98
0
No concentrations greater than criterion.
Cobalt
1 (pg/L)
Transition Zone: 1
1
1
2
Exceedances due to matching background values of 1.
Bedrock: 1.19
1
0.84
0
No concentrations greater than criterion.
Shallow: 0.974
<0.3
0
0
No concentrations greater than criterion.
Vanadium
0.3 (pg/L)
Transition Zone: 5.88
0.7
0.12
0
No concentrations greater than criterion.
Bedrock: 5.52
2
0.35
0
No concentrations greater than criterion.
Background Criteria
Shallow: 3.15
0.38
0.12
0
No concentrations greater than criterion.
Molybdenum
NE
Transition Zone: 1
5.3
5.26
2
Does not exhibit a discernable plume and does not correlate to boron plume.
Bedrock: 13.1
23.5
1.79
1
Does not exhibit a discernable plume and does not correlate to boron plume.
Shallow: 25
151.96
6.08
1
Concentration is attributed to transition zone and bedrock background groundwater based on updated CSM. Values are consistent with TZ and BR BTVs.
Strontium
NE
Transition Zone: 391
216.4
0.55
0
No concentrations greater than criterion.
Bedrock: 418
397.1
0.95
0
No concentrations greater than criterion.
Notes:
1 - Background values shown reflect those accepted by NCDEQ in June 15, 2018 letter. These values are currently being updated for re -approval from NCDEQ in 2019.
2 - Constituent list reflects the COI list identified in the CSA Update (SynTerra, 2018) with radium included per NCDEQ request (per Comments to CSA Update)
3 - The following wells were used to calcuate geomean concentrations at or near the compliance boundary: CW-02/D, CW-03, CW-04, CW-06, MW-03BR, MW-16S/D/BR❑
*IMAC
**Shallow background values come from transition zone
^ Federal MCL
pg/L - micrograms per liter
Highlighted value reference criterion
mg/L - milligrams per liter
NE - Not Established
Prepared by: DAA Checked by: ENK
Page 1 of 1

TABLE 3-7
GROUNDWATER BACKGROUND THRESHOLD VALUES AND
REGIONAL BACKGROUND CONCENTRATION RANGES
2018 CAMA ANNUAL INTERIM MONITORING REPORT
MAYO STEAM ELECTRIC PLANT
DUKE ENERGY PROGRESS, LLC, ROXBORO, NC
1
Constituent
Reporting
Unit
15A NCAC
02L Standard
Background Threshold ValueS2
Constituent Concentration Ranges
in Background Wells
Constituent Concentration Ranges in
Big 6 Piedmont Background Wells
Surficial
Flow Zone
Transition
Zone
Bedrock
Flow Zone
Surficial
Flow Zone
Transition
Flow Zone
Bedrock
Flow Zone
Shallow
Flow Zone
Deep
Flow Zone
Bedrock
Flow Zone
pH
S.U.
6.5-8.5
4.9-6.5
5.7-6.5
5.0-7.3
4.9-6.5
5.6-6.7
5.0-7.4
4.0-7.8
3.8-8.5
4.5-8.5
Arsenic
pg/L
10
1
1
1
<1
<1
<1
<0.1 - 1.1
<0.1 - 2.1
<0.1 - 3.13
Barium
pg/L
700
19
78
97
10 - 19
13 - 65
14 - 95
9.8 - 730
<5 - 146
<5 - 880
Boron
pg/L
700
50
50
50
<50
<50
<50
<50
<50
<50
Chromium
dig/L
10
3.23
6
7
<1 - 1.78
<1 - 4.6
<1 - 7.65
<0.5 -14.1
<0.5 - 19.5
<0.5 - 11.3
Chromium (VI)
pg/L
NE
0.088
1
0.4
0.038 - 0.16
<0.025 - 0.82
<0.025 - 0.47
<0.025 - 7.1
<0.025 - 12.2
<0.025 - 8
Cobalt
pg/L
1*
1.02
1
1.19
<1 - 1.59
<1
<1 - 6.53
<0.1 - 17.3
<0.1 - 6.1
<0.1 - 21.7
Iron
pg/L
300
385
1319
2550
108 - 6820
48 - 585
11 - 3260
<50 - 6820
<50 - 3200
<50 - 8730
Manganese
pg/L
50
253
298
544
11 - 395
18 - 237
<5 - 648
<5 - 780
<5 - 408
<5- 1510
Molybdenum
pg/L
NE
3.15
1
13.1
<1
<1
<1 - 12.9
<0.5 - 10.7
<0.5 - 30.2
<0.5 - 24.3
Strontium
pg/L
NE
25
391
418
12 - 27
83 - 391
131 - 430
<5 - 309
<5 - 782
<5 - 458
Sulfate
mg/L
250
1.6
7.5
18
0.85 - 2.2
0.96 - 5.8
0.21 - 140
<1 - 12.8
<1 - 48.1
<1 - 140
TDS
mg/L
500
85
430
340
26 - 110
65 - 420
66 - 510
<25 -164
<25 - 750
<25 - 820
Vanadium
pg/L
0.3*
0.974
5.88
5.52
<0.3 - 5.9
0.637 - 5.88
<0.3 - 4.74
<0.3 - 15.4
<0.3 - 24.4
<0.3 - 26.6
Notes:
* - Interim Maximum Allowable Concentrations (IMACs) of the 15A NCAC 02L Standard, Appendix 1, April 1, 2013.
pg/L - micrograms per liter
1 - Indicates that BTVs were calculated for constituents identified as a COI in the 2018 CSA Update (January 2018)
Z - Indicates that BTVs were calculated using data from background groundwater samples collected June 2015 to March 2017
BTV - Background Threshold Value
BTVs represent UTLs calculated from background datasets
COI - Constituent of Interest
CSA - Comprehensive Site Assessment
mg/L - milligrams per liter
NCAC - North Carolina Administrative Code
NE - Not Established
S.U. - Standard Units
TDS - Total Dissolved Solids
UTL - Upper tolerance limit
Nreparea oy: iMwMtS unecKea oy: MtL3
Page 1 of 1