NC0038377_R. Hennet - Final Mayo Expert Report_20160630

Expert Report of
Remy J.-C. Hennet
Mayo Steam Station
Roxboro, North Carolina
S.S. PAPADOPULOS & ASSOCIATES, INC.
Environmental & Water -Resource Consultants
June 30, 2016
7944 Wisconsin Avenue, Bethesda, Maryland 20814-3620 9 [phone]

Expert Report of
Remy J.-C. Hennet
Mayo Steam Station
Roxboro, North Carolina
Prepared for:
Duke Energy Carolinas, LLC
Prepared by:
Remy J.-C. Hennet, PhD
S.S. PAPADOPULOS & ASSOCIATES, INC.
Environmental & Water -Resource Consultants
June 30, 2016
7944 Wisconsin Avenue, Bethesda, Maryland 20814-3620 9 [phone]

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Table of Contents
Page
Listof Appendices.......................................................................................................................... ii
Section1
Introduction................................................................................................................
1
Section2
Background................................................................................................................
2
Section 3
Geochemistry of the Ash Basin.................................................................................
4
Section 4
Natural Attenuation in Groundwater.........................................................................
7
Section 5
Cap -in -Place Remedy................................................................................................
8
Section 6
Excavation and Removal...........................................................................................
9
Section7
Opinions...................................................................................................................
10
Opinion1..................................................................................................................
10
Opinion2..................................................................................................................
10
Opinion3..................................................................................................................
10
Section8
Bases for Opinions...................................................................................................
11
Opinion1..................................................................................................................
11
Opinion2..................................................................................................................
13
Opinion3..................................................................................................................
16
Appendices
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List of Appendices
Appendix A Curriculum Vitae of Remy J.-C. Hennet
Appendix B Documents Considered and/or Relied Upon
Appendix C Background Concentration Ranges — USGS, Site Data, and Private Wells
Appendix D Natural Attenuation — Ash Basin to Compliance Boundary
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REPORT

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Section 1
Introduction
This expert report was prepared by Remy J-C. Hennet. I am a Principal at S.S. Papadopulos
& Associates (SSP&A). I hold a Ph.D. degree in geochemistry and a Master's degree in geology
from Princeton University, and university degrees in hydrogeology and geology from the
University of Neuchatel, Switzerland. My expertise includes the application of geochemistry,
hydrogeology and geology to evaluate the origins, fate, and transport of chemicals in the
environment and the remediation of environmental problems. I have more than 25 years of research
and professional experience. My Curriculum Vitae and list of depositions and trial appearances
are provided as Appendix A. The hourly rate charged by SSP&A for my services is $272.
1 was retained by Duke Energy Progress, LLC. (Duke Energy) to evaluate the geochemical
data that has been collected to characterize the nature and extent of any groundwater contamination
from the operation of coal ash basin at the Mayo Steam Station, Roxboro, North Carolina (the
Site), and to evaluate whether impacts have occurred to surface waters and water supply wells. I
was also tasked to analyze and evaluate certain allegations made by Plaintiffs' experts Hutson and
Parette with regards to the appropriateness of the remedy that is proposed for the Site, cap -in -place
with monitored natural attenuation, and their contention that complete excavation of the ash is the
only acceptable remedy.
To conduct this evaluation and render my opinions, I relied on my education, research, and
professional experience. I reviewed the Comprehensive Site Assessment Report and the Corrective
Action Plan Part I and Part 2 reports for the Site. I also relied on the peer -reviewed literature and
various professional reports cited herein that describe coal ash materials. I retrieved data from
publically accessible internet sites (USEPA, USGS, and State web sites). I also visited the Site on
June 7, 2016. The data, documents and information that I considered are of the type that can be
reasonably relied upon to support my opinions. The information that I considered for this report is
listed as Appendix B.
The opinions presented in this report were reached by applying accepted methodologies in
the fields of geochemistry, hydrology, geology, and environmental remediation. The opinions
expressed in the report are my own and are based on the data and facts available to me at the time
of writing. Should additional relevant information become available, I reserve the right to
supplement the discussion and findings presented in this report.

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Section 2
Background
As required by the Coal Ash Management Act of 2014 (CAMA), Duke Energy conducted
a series of investigations and studies to characterize the potential for soil and groundwater
environmental impact from operation of its ash basin system. Duke Energy submitted a
Comprehensive Site Assessment Report and Corrective Action Plan Part 1 and Part 2 reports to
North Carolina Department of Environment and Natural Resources (NCDENR).
The potential source of contamination at the Site is the ash basin system at the Site. The
system consists of a single active basin. Ash is disposed of in a historical drainage feature
(Crutchfield Branch) that was dammed for impoundment. Site and ash basin operations started in
1983. The ash basin system is an integral part of the Site wastewater treatment system. The ash
basin system receives discharges from the ash removal system, coal pile runoff, landfill leachate,
flue gas desulfurization wastewater, the station yard drain sump, and site storm water.
Environmental impacts for groundwater occur when a party causes concentrations to
exceed the North Carolina Groundwater Quality Standards, as specified in 15A NCAC 2L.0202
(2L Standards). Concentration exceedances to the Interim Maximum Allowable Concentration
(IMAC) established by NCDENR pursuant to 15A NCAC 2L.0202(c) are also considered, even
though these standards have not been finalized. Surface water impacts are defined by concentration
exceedances to the North Carolina Surface Water Quality (2B) standards (2B Standards). The 2B
Standards depend upon classification of a surface water body.
For groundwater, the compounds of interest identified at the Site are: antimony, arsenic,
barium, boron, chromium, cobalt, iron, manganese, pH, thallium, total dissolved solids (TDS), and
vanadium. The compounds of interest were identified based on concentrations in groundwater that
exceed the 2L Standards and/or IMAC.
The available data for the Site includes results from chemical analysis of soil, sediment,
rock, ash basin solids, ash basin pore water, groundwater, seepages and surface water samples.
Leaching data were collected for samples of ash materials from the basin. The data include
information on mineralogical composition of geologic and ash materials, and general physical
characteristics for these materials in place (i.e., grain size, porosity, permeability). Site background
conditions were characterized through analysis of background soil, rock, and water samples.
Additional data and information on coal ash chemistry are available from peer -reviewed literature
and specialized professional reports.
The extent of groundwater contamination is described in the Comprehensive Site
Assessment Report and Corrective Action Plan reports for the Site. The Comprehensive Site
Assessment Report concluded that there is no identified imminent hazard to human health or the
environment as a result of soil or groundwater contamination at the Site. Additional work is on-
going at the Site to further delineate the extent of groundwater contamination where data gaps have
been identified.
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The Corrective Action Plan reports further evaluated the hydrology of the Site and the fate
and transport of contaminants in the groundwater environment. The reports examined the need for
remediation and the feasibility and adequacy of potential remedial measures for Site closure.
Based on its evaluation of the available data and information, Duke Energy selected a Cap-
in -place remedy for the ash basin, with additional source control measures being considered on an
as needed basis. The remedy consists of an engineered cap system over the ash basin and the
collection and treatment of storm water, runoff water, and seep water for permitted discharge. The
additional source control measures could include hydraulic containment, drains, amendments, and
other measures, as necessary to comply with future regulations and to address uncertainties and
unforeseen conditions. For the restoration of groundwater, Duke Energy has proposed to rely on
monitored natural attenuation. Monitoring after implementation of cap -in -place will provide the
basis for assessing the need for additional source control measures for groundwater restoration.
Plaintiffs' experts Hutson and Parette have submitted expert reports and opined that a Cap-
in -place remedy with monitored natural attenuation is inappropriate for the Site. These experts
opined that excavation and removal of the ash basin should be the remedy for the Site.
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Section 3
Geochemistry of the Ash Basin
Geochemical conditions across the Mayo Site are variable. Measured pH values are
variable with the majority of measured pH values ranging from 5 to 9 S.U. Approximate Eh values
range from -39 (bedrock beneath the ash basin) to about 500 mV in most bedrock wells outside of
the ash basin. Eh and pH conditions influence constituent speciation and sorption potential.
Chromium, cobalt, iron, manganese, and vanadium occur naturally at concentrations in Site
groundwater above their respective 2L values. Iron, manganese, and vanadium are ubiquitous in
Site groundwater regardless of location relative to the ash basin. Hexavalent chromium was
detected in downgradient groundwater at concentrations less than in an upgradient well.
Coal ash is a by-product from the combustion of coal. Under atmospheric conditions, some
of the minerals in coal ash are metastable and undergo transformations that lead to the formation
of secondary mineral phases that range from amorphous to crystalline (i.e., hydrous
aluminosilicates, mullite, calcite, etc.). Over time, the rate of chemical leaching decreases and the
formation of amorphous clays and other secondary minerals results in a decrease in coal ash
permeability (Jones and Lewis, 1956; Warren and Dudas, 1988; Zevenberg et al., 1999a and
1999b; Bolanz et al., 2012; Fruchter, 1990; Ghuman et al., 1999; Mudd et al., 2004; EPRI, 2009).
Depending on their properties, chemicals that are released or leached to pore water during
mineral alteration can remain in the pore water and/or can be sequestered in the secondary mineral
phases which are immobile. Sequestration in or immobilization onto the mineral phases can be
through absorption, adsorption, ion exchange, and secondary mineral precipitation and co -
precipitation.
The organic carbon content of coal ash, typically measured at the low percent level by
weight, provides a substrate for microbial activity. This activity depletes oxygen, making coal ash
pore water generally reducing or anaerobic. As for pH conditions, fresh coal ash pore water at the
Site is typically alkaline, whereas aged or weathered ash pore water tends to be neutral (reflecting
the mineral alterations and prolonged contact with carbon dioxide from the atmosphere). Ash and
coal materials that are exposed to atmospheric oxygen can become acidified as a side effect of the
oxidation of their sulfidic mineral content.
In the ash basin, the water (i.e., sluiced ash water, rain, storm water) that percolates through
the ash to groundwater has a distinctive chemical fingerprint. The chemical fingerprint reflects the
interaction between water and coal ash materials. Ash pore water is a sodium -calcium -sulfate
aqueous solution, meaning that these compounds dominate the dissolved concentrations. Boron,
chloride, strontium, magnesium, iron, manganese, and potassium are typically present at part per
million level. Aluminum, barium, and arsenic are typically present at the low part per million or
less level. Traces, at the part per billion level, are also typical for antimony, cobalt, vanadium and
molybdenum.
All of the constituents of interest occur in soils, rock, surface water, and groundwater under
background conditions. The background range concentrations can be lower, similar, or higher than
in the ash basin, depending on the compound considered. This is why it is necessary to account for
the background range for evaluating the environmental impacts of the ash basin. For groundwater
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background concentrations, data is available from the United States Geological Survey, the State
of North Carolina, and from the samples collected for Site characterization. The Site is located
within both the felsic mica gneiss (Charlotte Terrane) formation for the western portion of the ash
basin and within the felsic/mafic metavolcanic rock (Carolina Terrane) in the eastern portion
(USGS, 2005; USES, 2013b; Dicken, et al, 2007; Butler and Secor, 1991; Carpenter, 1976).'
Together and in context, these data inform on the background range for the compounds of concern.
Background data information for groundwater is illustrated in Appendix C.
The water that percolates from coal ash basin into subsurface soil and rock materials is put
in contact with different mineral phases that represent the geological materials onto which the coal
ash lies. Water -mineral interactions in the geological materials and mixing with groundwater result
in changes in chemical composition. Boron, because of its properties, remains in the water phase
and tends to transport conservatively (little or no retardation) with groundwater. Other chemicals
that include the constituents of interest, such as iron, manganese, arsenic and other trace
compounds in ash pore water, are not conservative and partition between the mineral and aqueous
(water) phases. Those reactive chemicals are attenuated in the subsurface environment by
immobilization and sequestration through mineral precipitation or co -precipitation and by
retardation through sorption and ion exchange processes. Iron is most important for attenuation in
the subsurface environment, as it is present at relatively high concentrations in ash and geological
materials. Iron minerals and mineral coatings are effective at attenuating (sequestering,
immobilizing, and retarding) other chemicals in groundwater (Dixit and Hering, 2003; Dzombak
and Morel, 1990; Stumm and Morgan, 1996).
Dissolved chemicals are present in groundwater as chemical species. The speciation of a
chemical is primarily controlled by the redox and pH conditions in the subsurface and by
interactions between chemicals in solution. The different chemical species of a given constituent
have different properties. It is therefore important to consider chemical speciation in the evaluation
of transport in the groundwater environment. For the compounds that are elevated in the ash pore
water and the impacted groundwater beneath and downgradient of the ash basin, the chemical
speciation can be derived from the Eh -pH diagrams (Atlas of Eh -pH Diagrams, 2005). Chemical
speciation informs whether a chemical can be reduced or oxidized and if its aqueous solubility is
controlled by mineral phases and/or other attenuating processes (e.g., sorption and ion exchange).
As part of the Site assessment work and studies that were conducted with Site materials,
solid -water partition coefficients (KD) were determined for 10 chemicals (arsenic, boron,
cadmium, chromium, iron, manganese, molybdenum, selenium, thallium, and vanadium). The
chemicals were dissolved in water and interacted with soil materials from the Site. The results
were obtained under controlled laboratory conditions and are not directly applicable to the Site
groundwater conditions; however, the results demonstrate that with the exception of boron, the
chemicals that were tested interact with the Site soil materials. The results demonstrate that
chemical attenuation is an active process at the Site for the tested compounds. Natural attenuation
for boron is dominated by physical attenuation and takes place principally through the
immobilization of the ash pore water and other physical processes that include dilution, diffusion,
and dispersion. Groundwater samples from wells screened within the ash contained elevated
I http://mrdata.usgs.gov/geology/state/state.php?state=NC
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concentrations of constituents of interest, confirming that attenuation is active with concentration
diminishing in the soil and rock materials beneath and downgradient of the ash basin (Appendix
D). These observations of concentrations attenuating away from the ash basin support Duke
Energy's decision to propose using monitored natural attenuation for the restoration of
groundwater as a supplement to the cap -in -place control measures.
The limited chemical interaction between boron and soil materials explains why boron is a
valid tracer for delineating the extent of the ash basin impacts; boron is typically present at low
concentration in background groundwater (<50 ug/L range) and its presence at high concentration
(-1000 ug/L range) in the ash pore water makes it a simple conservative tracer that can be used to
delineate the extent of groundwater affected by the ash basin and evaluate the effectiveness of
physical attenuation processes that would affect all mobile COI's equally. The results for the other
chemicals tested for chemical interactions support the conclusion that natural attenuation, both
physically and chemically, is active under Site conditions and that natural attenuation can be
considered as a restoration remedy for groundwater after the cap -in -place remedy has been
implemented.
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Section 4
Natural Attenuation in Groundwater
Natural attenuation results from physical, chemical, and biological processes that act alone
or in combination to reduce or decrease the volume of impacted groundwater and compound mass,
concentration, toxicity, and/or mobility in groundwater. The major processes that attenuate mass
or concentrations in groundwater are dilution, dispersion, absorption, adsorption, ion exchange,
precipitation, co -precipitation, complexation to organic substrate, and biomass accumulation. For
conservative compounds such as boron in groundwater, dilution and dispersion dominate
attenuation. For reactive compounds such as iron, manganese, or arsenic, adsorption, precipitation
and co -precipitation processes also attenuate concentrations in addition to dilution and dispersion.
USEPA provides guidance for the implementation of natural attenuation as a remedial
measure for groundwater contamination by inorganic compounds (EPA, Directive 9283.1-36,
August 2015; EPA 600-R-07-139; 2007a; EPA 600-R-07-140, 2007; EPA 600-R-10- 093, 2010;
EPA, Directive 9200.4-17P, April 21, 1999). The USEPA guidance provides objectives for the
performance of monitored natural attenuation:
1) Demonstrate that natural attenuation is occurring according to expectations;
2) Detect changes in environmental conditions (e.g., hydrogeologic, geochemical,
microbiological, or other changes) that may reduce the efficacy of any of the natural
attenuation processes;
3) Identify any potentially toxic and/or mobile transformation products;
4) Verify that the plume(s) is not expanding downgradient, laterally or vertically;
5) Verify no unacceptable impact to downgradient receptors;
6) Detect new releases of contaminants to the environment that could impact the
effectiveness of the natural attenuation remedy;
7) Demonstrate the efficacy of institutional controls that were put in place to protect
potential receptors; and
8) Verify attainment of remediation objectives.
As discussed in Section 8 of this report, the Site data indicate that natural attenuation is
occurring in the groundwater environment. The cap -in -place remedy will decrease the flux of
constituents of concern to groundwater and result in a decrease of the extent of the groundwater
impact. Monitored natural attenuation is therefore a valid remedial option for the restoration of
groundwater for this Site.
Progress toward the restoration of groundwater through natural attenuation will be
monitored once the cap -in -place remedy and additional source control measures, if any are
necessary, have been implemented. The monitoring data and information will be the basis for
selection of the final groundwater remedy for the Site.
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Section 5
Capin -Place Remed
The engineered cap -in -place remedy that Duke Energy plans to construct to cover the ash
basin will have the effect of greatly reducing the infiltration of water and wastewater through the
coal ash. The amount of ash pore water that will recharge to groundwater will be greatly
diminished and the flux of chemicals entrained with infiltration water will also decrease.
The ash materials have a high water retention capacity, meaning that absent recharge by
infiltration water, as under a cap -in -place remedy, the ash pore water is mostly immobile, further
decreasing the flux of constituents of interest from the ash materials to groundwater (Tiruta-Barna
et al. 2006).
Secondary mineral phases will continue to form in the coal ash and in the soil and rock
materials beneath the coal ash basin. The permeability of coal ash materials under the cap is
expected to continue to decrease over time, due to accumulation of secondary minerals in the pore
spaces. Groundwater -ash interactions will also decrease because of the lowering of the water table,
exposing less of the ash materials to groundwater. If monitoring of the cap -in -place remedy
indicates that restoration of groundwater is not taking place, additional source control measures
(i.e., drains, pumping, slurry walls) could be implemented to intercept the impacted groundwater
and/or to further depress the water table to further isolate the ash materials.
The geochemical conditions in the capped coal ash will remain generally reducing and
anaerobic from the continuous degradation of the organic substrate in the ash by micro-organisms,
with a pH condition near neutral to alkaline, depending on the age and degree of weathering of the
ash materials.
Under an uncapped condition, atmospheric oxygen is introduced into the ash materials with
infiltration water that contains dissolved oxygen. The atmospheric oxygen is consumed for the
oxidation of the organic substrate that is present in the ash materials. Consumption of oxygen takes
place primarily in the upper portion of the ash materials, as infiltration water progresses toward
the water table, and the effect of atmospheric oxygen is typically limited to the shallow ash. Under
a cap -in -place condition, the upper portion of the ash might possibly become more reducing. If
there was a reduction in atmospheric oxygen because of capping, it would result in more reducing
conditions in the pore water at depth in the ash materials. The geochemical result of more reducing
conditions would be for some increased sulfide activity from the reduction of sulfate to sulfide.
The presence of dissolved sulfide would result in the precipitation of sulfidic or pyritic minerals.
Under such reducing conditions, iron, manganese, and other metals dissolved in the pore water
would be precipitated or co -precipitated out of the pore water and become immobilized in the solid
matrix within the coal ash and beneath. Mineral precipitation and co -precipitation would remove
these constituents of interest from the aqueous phase, reduce their flux to groundwater, and
contribute to the restoration of groundwater.

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Section 6
Excavation and Removal
The excavation and removal of the ash in the ash basin and a portion of the soil materials
beneath the basin was considered by Duke Energy, but determined not to be the preferred remedy
for the Site based on environmental, engineering, social, and economic considerations.
Excavation is typically conducted using specialized machinery to removed materials that
are transported for disposal elsewhere. Excavation of the ash basin would expose subsurface soil
and rock materials to geochemical conditions that are different from the conditions with the ash in
place. A change in geochemical conditions would result in a rearrangement of the mineralogy in
the aquifer, with dissolution and precipitation of secondary mineralogy affecting groundwater
chemistry and redistributing the constituents of interest in the subsurface. The geochemical
disturbance will induce transient changes in the chemistry of groundwater that would only
gradually attenuate, long after the implementation of excavation.
The presence of sulfidic minerals in the soil and rock materials beneath the ash basin would
become oxidized by contact with infiltration water and atmospheric oxygen. Oxidation of sulfidic
minerals (i.e., pyrite) generates acidity, dissolved sulfate, and dissolved metals and metalloids that
are trace compounds of the minerals and are put into solution in the process. The acidity released
to groundwater would dissolve additional metals and metalloids from the soil and aquifer matrices.
The release of acidity to groundwater would decrease natural attenuation in the aquifer and
increase the leaching of natural occurring constituents of interest from native materials.
Excavation would not remove the impacted groundwater beneath and downgradient of the
excavation. The impacted groundwater that is left behind would serve as a long term source that
could sustain the groundwater impacts after excavation.
Excavation of the large quantities of materials in the ash basin would take time to
implement (i.e., years or decades). During that period of open excavation, precipitation, storm
water, and runoff water would enter the excavation in great quantities and infiltrate to groundwater.
This added infiltration would introduce additional contamination and force impacted groundwater
farther into the aquifer system, therefore increasing the extent of the existing groundwater impacts.
Geochemical processes that control aquifer restoration are typically slow and take time to
effectively achieve restoration goals. This would be true under both the excavation and cap -in -
place remedies.
There are anticipated negative effects with regards to groundwater for the excavation and
removal remedy advocated by Plaintiffs' experts. These effects have to be considered for a
comparative evaluation of the cap -in -place and excavation options.
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Section 7
Opinions
Based on my education and experience, and a detailed review of the available data and
information, I have reached the following opinions:
Opinion 1.
The constituents of interest at the Site are naturally occurring upgradient from the Site at
concentrations that are within the background range. Certain constituents of interest are present
under background conditions at concentrations that exceed the 2L Standards, IMAC, or 2B
Standards.
Opinion 2.
The cap -in -place remedy will decrease the flux of constituents of interest from the ash basin
to groundwater. Natural attenuation is and will continue to be active in the groundwater
environment, resulting in a future decrease in the mass and concentration of the constituents of
interest that are dissolved in groundwater. The cap -in -place remedy, supplemented by source
control measures if necessary, and monitored natural attenuation are a reasonable and adequate
remedy for the Site.
Opinion 3.
Excavation of the ash basin is not necessary for Site groundwater restoration. Excavation
alone cannot achieve the complete removal of the constituents of interest from the subsurface and
provides no substantial benefit over a cap -in -place remedy to restore groundwater.
I hold these opinions with a reasonable degree of scientific certainty. I reserve the right to
modify and supplement these opinions should additional information become available.
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Section 8
Bases for Opinions
Opinion 1.
The constituents of interest at the Site are naturally occurring upgradient from the
Site at concentrations that are within the background range. Certain constituents of interest
are present under background conditions at concentrations that exceed the 2L Standards,
IMAC, or 2B Standards.
The constituents of interest identified in the Comprehensive Site Assessment Report for
groundwater are: antimony, arsenic, barium, boron, chromium, cobalt, iron, manganese, pH,
sulfate, total dissolved solids, and vanadium. These compounds and parameters are naturally
occurring in natural soil and rock materials, surface water, and groundwater.
I reviewed the publically accessible USGS data (http://nwis.waterdata.usgs.gov/nwis
wdata) for the occurrence of constituents of interest in groundwater across North Carolina and
compared that information with the data presented in the Comprehensive Site Assessment Report
for the Site. Results are illustrated in Appendix C. The data sets compared include:
• Site background wells;
• Private water wells in the vicinity of the Site; and
• Site monitoring wells.
I also evaluated natural attenuation in groundwater using the available Site data. Results
are illustrated in Appendices D and E.
From this evaluation of the available data I conclude that for the Site:
• Boron is present at high concentration (— 1,000 ug/L) in the ash pore water and impacted
groundwater and at low concentration in groundwater under background condition (i.e.,
not detected or < 50 ug/L). Under the redox and pH conditions encountered in the
groundwater environment, boron is soluble in water and does not appreciably interact with
the solid matrix. Boron therefore transports with groundwater with little or no retardation.
Under Site conditions in the groundwater environment, boron can be considered a
conservative tracer for environmental fate and transport at the Site. Boron is attenuated in
groundwater primarily by dilution and dispersion (see Appendix D).
• Sulfate is present over a wide range of concentrations in the ash pore water and
groundwater beneath and downgradient of the ash basin. Sulfate concentration in
background groundwater can vary greatly, but is typically lower than in the impacted
groundwater. Sulfate is redox reactive and its concentration in groundwater can be
controlled by several processes that include mineral precipitation (i.e., barite, pyrite).
Sulfate is attenuated in groundwater primarily by dilution and dispersion. Additional
attenuation is provided by processes that can include mineral precipitation (i.e., barite) and
reduction of sulfate to sulfides under strongly reducing conditions.
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• Arsenic, iron, and manganese are reactive in the groundwater environment and do not
behave conservatively as boron does in groundwater. Arsenic, iron, and manganese can
occur within a wide range of concentrations in background groundwater (see Appendix Q.
The compounds are present in background soil and rock materials. These compounds are
sensitive to attenuation processes in the groundwater environment. Arsenic, iron, and
manganese attenuate in the groundwater environment through dilution and dispersion, in
addition, these compounds also attenuate through other processes (i.e., sorption, ion
exchange, mineral precipitation and co -precipitation) (see Appendix D). These compounds
can occur naturally at concentrations that exceed the 2L Standards. Manganese overall
attenuation can be less than for iron and arsenic, this does not mean that manganese is not
attenuated in groundwater.
• Trivalent chromium and hexavalent chromium form a redox pair, and both chemical
species are present in groundwater under background conditions. When not specified,
chromium refers to the sum of all chromium species in a sample. Hexavalent chromium
can form from trivalent chromium through oxidation under background conditions (Oze,
2007). The reducing conditions that prevail in the ash and impacted groundwater
environments at the Site are not amenable to the formation of hexavalent chromium, and
the amount of hexavalent chromium relative to trivalent chromium is small. Chromium and
hexavalent chromium are present in background groundwater, soil, and rock materials.
Chromium is also present in grout (Hewlett, 1988). There is no groundwater impact for
chromium from the ash basins as the reported detections of chromium are within the
background range.
• Antimony, cobalt, and vanadium are present at trace levels that are typically within the
groundwater background range. These compounds are present in soil and rock materials as
well as in ash materials. There is no impact for antimony or vanadium from the ash basin
and the reported trace detections are within the background range. Cobalt concentrations
are discussed further in the well by well discussion below.
The identified constituents of interest at the Site include pH and total dissolved solids. I
reviewed the pH and total dissolved solids data in the context of the available chemical data and
mineralogical information. 1 conclude that:
• The pH range in groundwater at the Site is within the background range and there are no
wells that report acidic pH (less than pH 5) or alkaline pH (more than pH 9) that could be
related to Site operations (see Appendix Q.
• Total dissolved solids represent the sum of all chemicals that are dissolved in a water
sample. This parameter does not inform on chemical composition, but can be used to
appreciate the overall dissolved content in water samples. Total dissolved solids can vary
over a large range in background groundwater and exceed the 2L Standard. Total dissolved
solids values are elevated in ash pore water and in the impacted groundwater beneath and
downgradient of the ash basin.
Boron concentrations in groundwater outside of the ash basin area exceed the 2L Standard
in two wells (MW-03 and CW-2). These wells are located at the base of the ash basin dam. Boron
is detected at concentrations below the 2L Standard in three wells (CW-2D, CW-1, and MW-
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14BR). The extent of detectable boron reflects the extent of groundwater impacts from the ash
basin (see Appendix Q.
Arsenic concentrations do not exceed the groundwater 2L Standard outside of the ash basin
area. Iron and manganese concentrations in groundwater outside of the ash basin are within the
background range (see Appendix Q. The background range for iron and manganese includes the
2L Standards. There is therefore no arsenic, iron or manganese impact above the background
range. Manganese concentrations are at the upper end of the background range, and boron is also
detected beneath and downgradient of the ash basin. The presence of detectable boron, coupled
with manganese at the upper end of the background range, indicates that the ash basin could
possibly contribute to the manganese concentrations. Under a cap -in -place remedy, recharge
through the capped ash materials will all but cease and groundwater recharge will be from outside
of the ash basin. With less contribution from the ash basin, conditions in groundwater will evolve
toward more oxidizing. Under a more oxidizing condition, manganese is expected to attenuate
though mineral precipitation and co -precipitation. Groundwater monitoring will provide a basis to
evaluate the need for amendments to further decrease the manganese concentration, if necessary.
The constituents of interest antimony, barium, chromium, cobalt, sulfate, and vanadium
are present at concentrations that are within the background range. The background range for these
constituents includes the 2L Standards and IMAC. There is no impact to groundwater from the ash
basin for these constituents at the Site (see Appendix Q.
Concentrations in groundwater that exceed a criterion (2L Standard or IMAC) but that are
within the background range are not indicative of a coal ash impact to groundwater. At the Site, a
coal ash impact to groundwater is indicated by the presence of a geochemical fingerprint that
includes boron, alone or together with other compounds of interest, at concentrations that are
higher than the upper bound of the background range.
Opinion 2.
The cap -in -place remedy will decrease the flux of constituents of interest from the ash
basin to groundwater. Natural attenuation is and will continue to be active in the
groundwater environment, resulting in a future decrease in the mass and concentration of
the constituents of interest that are dissolved in groundwater. The cap -in -place remedy,
supplemented by source control measures if necessary, and monitored natural attenuation
are a reasonable and adequate remedy for the Site.
The cap -in -place remedy proposed by Duke Energy and additional source control measures
that will be implemented, if necessary, will decrease the flux of the constituents of interest from
the ash basin to groundwater. This will be beneficial to Site remediation and groundwater
restoration. The decrease in flux will be accompanied by a reduction of the extent of the
groundwater plume and will allow natural attenuation to proceed at an accelerated rate toward
restoration. The cap -in -place remedy will therefore represent a net improvement for groundwater
quality beneath and downgradient of the ash basin.
There is no human exposure to the impacted groundwater, and no imminent need for
aggressive remediation beyond the actions that Duke Energy is planning for the Site. The addition
of monitored natural attenuation to the source control measures will provide the means to follow
the progress of groundwater restoration.
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�S
The remediation planned by Duke Energy has flexibility built in to address unforeseen
events or to implement additional remediation at the local scale, should such measures be
necessary. For example, the interception of impacted groundwater (i.e., via pump and treat or some
form of hydraulic controls) could be implemented in some portions of the ash basin, to complement
the cap -in -place remedy if the restoration of groundwater does not occur as anticipated.
The constituents of interest attenuate in the groundwater environment. Boron attenuates
primarily by dilution and dispersion, and other constituents attenuate by dilution and dispersion
and through other processes that include sorption, mineral precipitation, and ion exchange. This is
illustrated in Appendix D for boron, arsenic, iron, and manganese.
Plaintiffs' expert Parette has opined that monitored natural attenuation is not an appropriate
remedy for the constituents of interest at the Site. Parette apparently based this on statements in
the Comprehensive Site Assessment Report and Corrective Action Plan Part 1 and Part 2 reports
that he took out of context. Duke Energy's proposed remedy for the Site is to implement a cap -in -
place remedy supplemented by source control measures, if necessary, with monitored natural
attenuation for groundwater restoration. The performance of the remedy will be evaluated through
monitoring, and a final groundwater remedy will be selected based on that information.
Furthermore, as discussed in Sections 4 and 5 above, natural attenuation for the constituents of
interest is active at the Site, and will remain active upon implementation of the cap -in -place
remedy.
Parette has opined that the utilization of monitored natural attenuation in combination with
a cap -in -place remedy is problematic, as he believes conditions would be less favorable for natural
attenuation following capping. First, less favorable conditions do not imply that natural attenuation
is not taking place or cannot restore groundwater; and less favorable conditions do not negate the
merits of natural attenuation. Second, one main reason given by Parette for this opinion is that
capping of the ash basins would lead to more anoxic conditions in the Site groundwater. The coal
ash pore water and the impacted groundwater are already depleted of dissolved oxygen
(anaerobic). Water that contains atmospheric oxygen and infiltrates into the ash, is readily depleted
of its oxygen which is utilized to oxidize the organic content of the ash materials (the organic
carbon content is reported to be at the percent level, providing an ample supply of organic substrate
to sustain microbial activity in the ash materials). A cap would not change the situation, with the
exception of a shallow zone of ash materials where oxygen from infiltration water is utilized to
degrade the organic substrate in the ash in the absence of a cap. In the impacted groundwater
environment, the conditions are typically reducing and anaerobic, and oxygen does not reach
groundwater by infiltration through the ash. Third, some dissolved oxygen is present in the shallow
groundwater upgradient from the ash basins; that condition will remain after capping. Furthermore,
the available data demonstrate that natural attenuation is active at the Site (see Appendix D), and
in the portion of the aquifer that has been impacted by the ash basin, the ratio of upgradient
groundwater to the water that percolates through the ash will increase under the cap -in -place
remedy. This will increase, not decrease, the rate of natural attenuation.
Parette opined that monitored natural attenuation should not be selected to remedy arsenic
at the Site and that the cap -in -place remedy would likely increase the mobility of arsenic in
groundwater. There are several reasons why the cap -in -place remedy does not negate the use of
natural attenuation for the restoration of groundwater at the Site. Arsenic is amenable to natural
14

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�S
attenuation in the groundwater environment, as discussed above. The reduction of the infiltration
flux through the ash materials relative to the flux of groundwater from upgradient is expected to
increase arsenic attenuation in groundwater, not the reverse. In addition, more reducing conditions
in the ash materials would result in increased sulfide activity leading to the precipitation or co -
precipitation of arsenic with sulfide minerals. This sequestration of arsenic in the ash materials
would further decrease the arsenic flux from the ash to groundwater.
Plaintiffs' expert Hutson opined that dilution is not part of natural attenuation, that many
of the ash -related constituents in groundwater at this site neither degrade nor attenuate, and that
monitored natural attenuation is not an acceptable groundwater remediation strategy at the Site. First,
dilution is a natural process that cannot be avoided in the groundwater and surface water
environments. As discussed in Section 4 above, natural attenuation results from several processes,
one of which is dilution. USEPA guidance also includes dilution as a natural attenuation process
(EPA, Directive 9283.1-36, August 2015; EPA 600-R-07-139; 2007a; EPA 600-R-07-140, 2007;
EPA 600-R-10- 093, 2010; EPA, Directive 9200.4-17P, April 21, 1999). Second, the Site data
demonstrate that natural attenuation is active in groundwater at the Site (see Appendix D). Third,
Hutson misrepresents the remediation strategy proposed by Duke Energy. The remediation
strategy proposed by Duke Energy is a cap -in -place remedy with monitored natural attenuation for
groundwater restoration, and additional source control measures, if necessary, to comply with
future regulations and to address uncertainties and unforeseen conditions at the Site. Hutson is
incorrect and misrepresents the groundwater remediation strategy proposed for the Site.
Parette opined that the partition coefficients (KD) obtained from the testing of Site materials
in the laboratory are biased high because the synthetic groundwater used for the tests did not
contain all the chemical species present in Site groundwater. Because of this, Parette appears to
imply that because of this alleged bias, monitored natural attenuation is not appropriate for the
restoration of groundwater. Even if all chemical species present in Site groundwater had been
incorporated in the synthetic groundwater for testing, the main conclusions from the testing would
remain valid. The main conclusion from the testing is that the constituents of interest in
groundwater do interact with the solid matrix, demonstrating the occurrence of attenuation.
Running the tests with all chemical species incorporated in the synthetic groundwater might have
decreased somewhat the experimental KD values; however, this effect would not be a basis to
negate the conclusion that the dissolved constituents of interest interact with the Site solid matrices
that were tested. Boron is the exception, for which the testing showed that attenuation by
interaction with the solid matrix does not contribute substantially to attenuation. Attenuation for
boron is primary through dilution and dispersion, as discussed under Section 3 above.
Parette has opined that natural attenuation is impaired because of the presence of silica,
phosphate, bicarbonate, and dissolved organic carbon, and by the formation of complexes between
chemical species in groundwater. Competition between chemicals and complex formation in
groundwater does not mean that natural attenuation is not active for the constituents of interest at
the Site. The fact that the available data demonstrate that natural attenuation is active at the Site,
as discussed above, indicate that these impairments are not important and do not negate natural
attenuation. Parette's opinion is therefore not a basis to reject the monitored natural attenuation
aspect of the planned remedy for the Site.
15

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1SU
Opinion 3.
Excavation of the ash basin is not necessary for Site groundwater restoration.
Excavation alone cannot achieve the complete removal of the constituents of interest from
the subsurface and provides no substantial benefit over a cap -in -place remedy to restore
groundwater.
The excavation and removal of the ash in the ash basin and a portion of the soil materials
beneath the basin was evaluated by Duke Energy and determined not to be the best remedy for the
Site. Cap -in -place control measures with monitored natural attenuation combined with additional
control measures, if necessary, was selected as a better remedy for the Site. The determination is
based on a technical evaluation of the merits and limitations of these two options.
Excavation and complete removal of ash and shallow soil materials from the ash basin is
the remedy that Plaintiffs' experts advocate for the Site. I disagree with that conclusion for the
following major reasons (see also Sections 5 and 6 above):
• The engineered cap -in -place control measures that Duke Energy plans to construct to cover
the ash basin will have the effect of greatly reducing the infiltration of water and
wastewater through the coal ash. The amount of ash pore water that will recharge to
groundwater will be greatly diminished and the flux of chemicals entrained with infiltration
water will decrease.
• Natural attenuation will provide for a gradual restoration of the impacted groundwater
under either the cap -in -place or excavation scenarios. Geochemical processes that control
aquifer restoration will be slow and gradual and will require a long period of time (i.e.,
years or decades) under both the excavation and cap -in -place remedies.
• Excavation would not remove all the ash materials. It is simplistic to assume that
excavation at the scale promoted by Plaintiffs' experts would be able to remove the totality
of the ash at the Site. Ash materials were placed on bare soils for several decades, and some
ash most likely penetrated deeper in the subsurface than can be reached by the excavation
promoted by Plaintiffs' experts.
• Excavation would not remove the impacted groundwater beneath and downgradient of the
excavation. The residual mass of ash materials and the impacted groundwater would serve
as long term sources and sustain the groundwater impacts.
• Excavation will disturb large volumes of coal ash and expose chemically reduced materials
to atmospheric oxygen and water. A change in geochemical conditions would result in a
rearrangement of the mineralogy of the aquifer, with dissolution and precipitation of
secondary mineralogy affecting groundwater chemistry and redistributing the constituents
of interest in the subsurface. The geochemical disturbance would induce transient changes
in the chemistry of groundwater that would only gradually and slowly attenuate long after
the implementation of excavation.
• Excavation of the large quantities of materials in the ash basin would take time to
implement (i.e., years or decades). During that period of open excavation, precipitation,
storm water, and runoff water would enter the excavation in great quantities and infiltrate
to groundwater. This added infiltration would introduce additional contamination and force
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impacted groundwater farther into the aquifer system, thereby increasing the extent of the
existing groundwater impacts.
Plaintiffs' expert Hutson opined that removal of the coal ash by excavation will remove the
source and reduce the concentration and extent of groundwater and surface water contaminants. Hutson
relies on model predictions from the Correction Action Plan reports, even though he criticizes the
model for not reflecting real -world conditions. Hutson wrongly assumes that the source of
contamination would be entirely removed by the excavation remedy. The excavation would not
remove the impacted groundwater. The excavation would not remove the mass of contaminants
that is stored by sorption and mineral coatings in the soil, rock and aquifer materials that could not
be excavated. The excavation would also not remove the naturally occurring compounds of
concern that are components of the native soil and rock materials. Furthermore, the excavation
would not remove residual ash materials that could have penetrated into the subsurface beyond the
extent of the excavation.
Hutson opined that a cap -in -place remedy will not be protective of surface water quality in
Crutchfield Branch. First, Hutson ignores the fact that the remedy proposed by Duke Energy consists
of a cap -in -place remedy with additional source control measures being considered, if necessary.
The remedy consists of an engineered cap system over the ash basin and the collection and
treatment of storm water, runoff water, and seep water for permitted discharge. The additional
source control measures could include hydraulic containment, drains, amendments, and other
measures, as necessary to comply with future regulations and to address uncertainties and
unforeseen conditions. For the restoration of groundwater, Duke Energy has proposed to rely on
monitored natural attenuation. Monitoring after implementation of cap -in -place will provide the
basis for assessing the need for additional source control measures for groundwater restoration.
The cap -in -place remedy supplemented by source control measures on an as needed basis to restore
groundwater will be protective of surface water quality in Crutchfield Branch. Second, Hutson
fails to consider that the excavation remedy by its own cannot remove the entirety of the source of
constituents of interest at the Site, and that under an excavation remedy, source control measures
might also be required to protect surface water in Crutchfield Branch.
Hutson opined that the cap -in -place remedy will not protect groundwater quality
downgradient of the ash basin. The engineered cap -in -place remedy that Duke Energy plans to
construct to cover the ash basin will have the effect of greatly reducing the infiltration of water
and wastewater through the coal ash. The amount of ash pore water that will recharge to
groundwater will be greatly diminished and the flux of chemicals entrained with infiltration water
will also decrease. Duke Energy has proposed to rely on monitored natural attenuation for the
restoration of groundwater. Monitoring will provide data and information that will be used to
determine whether source control measures will be necessary for groundwater restoration. Hutson
fails to consider and address the fact that an excavation remedy would not immediately restore
groundwater, as discussed previously in this report.
17

APPENDICES

Appendix A
Curriculum Vitae of Remy J.-C. Hennet

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REMY J.-C. RENNET
Geochemist
AREAS OF EXPERTISE
■ Geochemistry, Hydrogeology, Geology
■ Origin, Fate, and Transport of Chemicals
in the Environment
SUMMARY OF QUALIFICATIONS
A geochemist with 25 years of research and professional
experience, Dr. Hennet specializes in evaluating the origin,
fate, and transport of organic and inorganic chemicals in
the environment. Dr. Hennet is often retained as an expert
witness for litigation in providing services to industry, law
firms, and the U.S. Department of Justice. His areas of
expertise include the analysis of geochemical fingerprints,
the evaluation of the timing of chemical releases, allocation
of responsibilities, geochemical modeling, and the
evaluation and application of novel on -site technologies to
solve environmental problems. He is a member of the
American Academy of Forensic Sciences, the American
Chemical Society, and the Association of Groundwater
Scientists and Engineers. He was awarded the Woods
Hole Oceanographic Institution's Postdoctoral Scholarship
in 1987 and has numerous publications in the fields of
inorganic and organic geochemistry.
REPRESENTATIVE EXPERIENCE
S.S. Papadopulos & Associates, Inc., Bethesda,
Maryland
■ Environmental Forensics
■ Litigation Support
U.S. Department of Justice — Served as an expert
witness for several environmental litigation cases.
Examples of this work include: the quantification of the
history of benzene flux from the subsurface to ambient
air following the release of military jet fuel; the
evaluation of multi -source petroleum hydrocarbon
releases and their individual extent; the evaluation of
the impact of bleaching agent when released in a
desert environment; the impact and duration of large
herbicides, and other products); and the origin, fate,
chlorinated solvents at several military bases.
YEARS OF EXPERIENCE: 25+
EDUCATION
PhD - Geochemistry, Princeton
University, 1987
MA -Geology, Princeton University,
1983
Diplome - 3eme Cycle, Hydrogeologie,
Universite de Neuchatel, 1981
Diplome - Geologie, Sciences Exactes,
Universite de Neuchatel, 1980
REGISTRATIONS
Certified Professional Geological
Scientist: No. 10572, American
Institute of Professional Geologists
Licensed Professional Geoscientist:
Texas No. 425
PROFESSIONAL HISTORY
S.S. Papadopulos & Associates, Inc.:
Principal, 1989 to present
Woods Hole Oceanographic
Institution: Postdoctoral Scholar,
1987-1989
Princeton University: Research
Assistant, 1983-1987; Teaching
Assistant, 1982-1985
Universite de Neuchatel: Research
Assistant, 1980-1981
scale pesticide applications (fumigants,
transport, and timing of the release of
Atlantic Richfield Company, Montana —Provided technical support for natural resource damage
litigation and testified as an expert witness. For the Anaconda tailings ponds site, collected data for
a modeling simulation of the fate and transport of dissolved arsenic and cadmium in the alluvium
beneath and down -gradient of the ponds. For the Butte mining district, evaluated the background
condition for metals, arsenic, and sulfur chemical species. For the Montana Pole wood treatment
site, evaluated the mobility of arsenic and pentachlorophenol (PCP) in the groundwater
environment. For the Milltown Reservoir on the Clark Fork River; evaluated the background
conditions and the mobility of metals and arsenic chemical species in sediments accumulated
behind the reservoir.
■ Allocation of Responsibility and Costs (Confidential Clients), Nationwide — Reviewed and
interpreted large volumes of information to support multi -party allocation models.

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• Atlantic Richfield/BP, California, Nevada — Provided a detailed evaluation of the design and
performance of abatement measures at closed sulfur and copper mines. Applied geochemical
fingerprints and performed modeling to evaluate the origin fate and transport of contamination.
■ Rhone Poulenc Corporation, Pennsylvania, California, and New Jersey — Studied arsenic
fixation in soil material by various physicochemical treatments as part of a collaborative effort with
Pennsylvania State University, with a focus on understanding the processes that control the fixation
of arsenic in soils. Advised on the interpretation of data to characterize the mobility of arsenic
chemical species at the Bay Road Site in the San Francisco Bay area, and at the Factory Lane Site
in New Jersey.
■ Panhandle Eastern Pipeline Company — Evaluated and characterized the fate, transport, and
distribution of polychlorinated biphenyls (PCBs) in the subsurface at several sites along a major
pipeline system. Pipeline liquid condensate was discharged to unlined pits located at pumping
stations spread along the system. The condensate contained PCBs from the operational bleeding
of oil from gas pressurization turbines. The disposal of condensate resulted in surface and
subsurface contamination by PCBs and light hydrocarbon compounds. Provided guidance in site
characterization, site remediation, and to the site closure process.
• Envirosafe Services Landfill, Toledo, Ohio —Reviewed detailed organic, inorganic, and isotope
data to evaluate the integrity of a large active landfill complex located in an area characterized by
historical waste disposal activity.
■ Lone Pine Superfund Site, Freehold, New Jersey —Performed data collection and interpretation
to predict chemical composition for the design of a treatment facility.
■ Heleva Superfund Site, Allentown, Pennsylvania —Conducted specialized sampling to assess
trace amount of chlorinated hydrocarbons in acetone -rich groundwater. Acquired isotope and
nutrient data to characterize subsurface conditions for natural attenuation and design of the
treatment plant.
• Love Canal, Niagara Falls, New York, and Stringfellow, Glen Avon, California, Superfund Sites
— Performed detailed data interpretations to assess the validity of expert witness' testimonies
related to the fate, behavior, and migration of toxic chemicals in the subsurface.
■ Tyson Superfund Site, Pennsylvania — Conducted a detailed technical investigation of the
performance of a large vacuum -extraction system consisting of more than 250 individual extraction
wells. The extraction of volatile organic compounds was impeded by subsurface heterogeneities
and the presence of residual non -aqueous phase liquids in the subsurface.
■ Little Mississinewa River Superfund Site, Union City, Indiana, — Several miles of river
sediments were contaminated with waste oil containing elevated PCBs, and PCTs, PAHs, and
metals. The main sources of contamination consisted of two major industrial outflows that
discharged to the river over a period of several decades. Using chromatograms and raw electronic
instrument response data from the analysis of about 200 samples, characterized the chemical
fingerprints of both sources and quantified relative contributions.
■ Coronet Company, Florida —Provided a detailed evaluation of the fate and transport of arsenic,
boron, radium, polonium, and other chemicals in soil, ponds sediment, and groundwater at a former
phosphate mining and fertilizer processing plant. Conducted geochemical modeling.
• White Pine Sash Superfund Site, Missoula, Montana —The release of wood treatment product
containing pentachlorophenol (PCP) in diesel resulted in contamination of the vadose zone above
a major water supply aquifer. Chlorinated-dioxins/furans were also detected in soil samples.
Concurrently with the PCP product release(s), diesel/fuel oil No 2 had been released from
underground storage tanks in the area. Evaluated and delineated the extent of impact of the
diesel/fuel oil No 2 release independently of the PCP -diesel release(s).

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• CSX Transportation, Florida — Evaluated the origin(s) fate and transport of arsenic in the
environment.
• Titan Tire Corporation, Iowa — Evaluated the origin of PCB contamination and conducted a
detailed review of laboratory data packages.
■ Uranium Mine Tailings, New Mexico —Evaluated tailings piles (from the processing of uranium
ore) for water balance, dewatering, contaminant flux to groundwater, the progress of groundwater
plume development, and the effects of remedial measures. Recommended dose reconstruction in
water wells.
■ Citizens about Rushton Rezoning, Inc., South Lyon, Michigan — Analyzed the potential
environmental and hydrogeological impacts of water -treatment lagoons and infiltration spraying
fields. Calculated the fate and transport of nitrogen and phosphorous in the soil and groundwater.
[The lagoons and spraying fields were selected as a wastewater treatment for a large residential
development. The spraying fields were located on sloped glacial till that has limited permeability
and capacity. Regulated surface -water bodies were located adjacent to the spraying fields and
lagoons.]
Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
Studied the organic and inorganic chemistry of the Guaymas Basin hydrothermal system.
Performed detailed trace analyses of metals and petroleum hydrocarbons. The research included
the use of the research submarine Alvin for in -situ parameter measurements and sampling.
Researched and studied the formation of natural petroleum and the effects of organic molecules
degradation and migration on the formation of geopressured zones.
Princeton University, Princeton, New Jersey
As Research Assistant, studied metal -organic interaction in natural settings, and served as Senior
Thesis Advisor for an experimental study of lead -organic complexing and for an experimental study
of trichloroethane in groundwater. Served as Teaching Assistant in Historical Geology and
Geomorphology.
Universite de Neuchatel, Centre d'Hydrologie, Switzerland
Studied tritium in groundwater and performed related laboratory work. Conducted geochemical
fingerprinting in carbonate terrains as applied to the development of water resources.
PROFESSIONAL SOCIETIES
American Academy of Forensic Sciences
American Chemical Society
American Institute of Professional Geologists
Geological Society of America
National Ground Water Association — Association of Ground Water Scientists and Engineers
HONORS & AWARDS
Postdoctoral Scholar, Woods Hole Oceanographic Institution, 1987-1989
Princeton University Fellowship, 1982-1987
Swiss National Science Foundation Fellowship at Princeton University, 1981-1982
Mention Bien, Geologie, Universite de Neuchatel, 1980

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APPOINTMENTS
2002-2005: Geological Sciences Advisory Board, University of Alabama.
1996-2001: Member of Governing Board, Association of Princeton Graduate Alumni.
2000: Convenor, THEIS 2000 Conference: Iron in Groundwater, National Ground Water
Association.
1993-1999: Technical Advisory Board, Xetex Corporation.
1989-1992: Member of Steering Committee, Working Group 91, Scientific Commission for
Oceanic Research.
PUBLICATIONS
Soderberg, K., D.P. McCarthy, and R. J.-C. Hennet, 2015. Volatilization of Polychlorinated Biphenyls:
Implication for their Distribution, Forensics and Toxicity in Urban Environments. Presentation at
the Geological Society of America Annual Meeting, November 1-4, 2015, Baltimore, MD.
Soderberg, K. and R.J.-C. Hennet, 2014. Detection of Pharmaceuticals in the Environment: History
of Use as a Forensic Tool. in Goldstein, W. ed. Pharmaceutical Accumulation the Environment:
Prevention, Control, Health Effects and Economic Impact. CRC Press: Boca Raton, FL. 262 p.
Hennet, R.J.-C, 2010. PCBs in the Interstate Natural Gas Transmission System — Status and
Trends. White Paper prepared for the Interstate Natural Gas Association of America.
Hennet, R.J.-C, 2010. Working with Lawyers: The Expert Witness Perspective. United States
Attorneys' Bulletin, v. 58, no. 1, pp. 14-17.
Soderberg, K., and R.J.-C. Hennet, 2007. Uncertainty and Trend Analysis -- Radium in
Groundwater and Drinking Water. Ground Water Monitoring and Remediation, v. 27, no. 4, pp.
122-127.
Soderberg, K., R. Hennet, and C. Muffels, 2005. Uncertainty and Trend Analysis for Radium in
Groundwater and Drinking Water (abstract). Presentation at the 2005 National Ground Water
Association Conference on Naturally Occurring Contaminants: Arsenic, Radium, Radon, and
Uranium, February 24-25, 2005, Charleston, SC. in Abstract Book, pp. 30-44.
Hennet, R.J.-C, 2002. The Application of Stable Isotope Ratios in Environmental Forensics. in
American Academy of Forensic Sciences Proceedings, pp. 103-104.
Hennet, R.J.-C, 2002. Life is Simply a Particular State of Organized Instability. in Fundamentals of
Life, G. Palyi et al., eds. Paris, France: Elsevier, pp. 109-110.
Hennet, R.J.-C., and L. Chapp, 2001. Using the Chemical Fingerprint of Pharmaceutical
Compounds to Evaluate the Timing and Origin of Releases to the Environment. in Proceedings
of the American Academy of Forensic Sciences, v.4, no. 1, p. 101.
Vlassopoulos, D., C. Andrews, R. Hennet, and S. Macko, 1999. Natural Immobilization of Arsenic in
the Shallow Groundwater of a Tidal Marsh, San Francisco Bay. Presentation at the American
Geophysical Union Spring Meeting, Boston, MA, May 31-June 4, 1999.
Hennet, R.J.-C, D. Carleton, S. Macko, and C. Andrews, 1997. Environmental Applications of
Carbon, Nitrogen, and Sulfur Stable Isotope Data: Case Studies (abstract). Invited speaker at
the Geological Society of America Annual Meeting, Salt Lake City, UT, November.
Jiao, J., C. Zheng, and R. Hennet, 1997. Analysis of Under -pressured Reservoirs for Waste
Disposal. Hydrogeology Journal, v.5, no. 3, pp. 19-31.

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Jiao, J., C. Zheng, and R. Hennet, 1995. Study of the Feasibility of Liquid Waste Disposal in
Underpressured Geological Formations. Proceedings of the American Geophysical Union Spring
Meeting, Baltimore, MD, May 30—June 2, 1995. in Eos Supplement, v. 76, no. 17, S137.
Vlassopoulos, D., P. Lichtner, W. Guo, and R. Hennet, 1995. Long -Term Controls on Attenuation of
Mine -Waste Related Contamination in Alluvial Aquifers: The Role of Aluminosilicate Clay
Minerals. Proceedings of the American Geophysical Union Spring Meeting, Baltimore, MD, May
30-June 2, 1995. in Eos Supplement, v. 76, no. 17, S150.
Feenstra, S., and R. Hennet, 1993. Assessment of Performance Limitations on Soil Vapor
Extraction (SVE) in Variable Soils. The Newsletter of the Association of Ground Water Scientists
and Engineers, v. 9, no. 3, pp. 112-113.
Hennet, R.J.-C., and S. Feenstra, 1993. Assessment of Performance Limitations on Soil Vapor
Extraction (SVE) in Variable Soils (abstract). Presentation at the Symposium on Chlorinated
Volatile Organic Compounds in Ground Water, National Ground Water Association 45th Annual
Convention, Kansas City, MO, October 17-20, 1993. in Ground Water, v. 31, no. 5, pp. 828-829.
Hennet, R.J.-C., and C. Andrews, 1993. PCB Congeners as Tracers for Colloid Transport in the
Subsurface —A Conceptual Approach. in Manipulation of Groundwater Colloids for
Environmental Restoration. Ann Arbor, MI: Lewis Publishers, pp. 241-246.
Hennet, R.J.-C, 1992. Abiotic Synthesis of Amino Acid Under Hydrothermal Conditions and the
Origin of Life: A Perpetual Phenomenon? Invited speaker at the Gordon Research Conference
on Organic Geochemistry, New Hampshire.
Hennet, R.J.-C, N. Holm, and M. Engel, 1992. Abiotic Synthesis of Amino Acid Under Hydrothermal
Conditions and the Origin of Life: A Perpetual Phenomenon? Naturwissenschaften, v. 79,
pp. 361-365.
Hennet, R.J.-C, and N. Holm, 1992. Hydrothermal Systems: Their Varieties, Dynamics, and
Suitability for Prebiotic Chemistry. in Origins of Life and Evolution of the Biosphere, Netherlands,
v. 22, pp. 15-31.
Holm, N., A. Cairns -Smith, R. Daniel, J. Ferris, R. Hennet, E. Shock, B. Simoneit, and H. Yanagawa,
1992. Future Research. in Origins of Life and Evolution of the Biosphere, v. 22, pp. 181-190.
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2

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7

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0

Appendix C
Background Concentration Ranges - USGS,
Site Data, and Private Wells

2.2- bV6VD06nr oe 8F b220CIVIE2' INC'
Appendix C Explanation Sheet
Background concentration cumulative distribution plots were created for the following analytes:
• Boron
• Chromium
• Sulfate
• Antimony
• Arsenic
• Vanadium
• Iron
• Cobalt
• Manganese
• pH
• Barium
• Total Dissolved Solids
The cumulative distribution plots illustrate the differences in the range of concentrations sampled from
different locations. Locations (site background wells, private wells, and USGS wells) can be compared by
the relationships between their sample concentrations at different percentiles.
Data Sources
The site background data was obtained from the from the Duke Energy MANAGES environmental
database, queried on 6/23/2016 by Tim Hunsucker.
USGS well dataset was obtained from the USGS National Water Information System' (NWIS). The NWIS
was queried on 6/10/2016 for all groundwater data from North Carolina wells for the analytes listed
above. The NWIS query results did not contain data for total boron or total vanadium.
The private well data was obtained from the NC DEQ websitez from the document "Full Well Water
Testing Results For Posting 8.2031,. Estimated values (J qualifier) were omitted from the analysis for the
private well data.
Data Handling
The following site wells were considered background wells for the calculations:
• BG-1
• BG-2
• MW-10BR
• MW-11BR
• MW-12D
• MW-12S
• MW-14BR
All non -detects samples in the site background and private wells datasets were set to one half their
detection limit.
1 http://nwis.waterdata.usgs.gov/nwis/qwdata
z https://deg.nc.gov
3 https://ncdenr.s3.amazonaws.com/s3fs-public/document-
libra ry/Full%20WeII%20Water%20Testing%20Results%20For%2OPosting%208.20.pdf

2.2- bV6VD06nr'o2 8F b220CIVIE2' INC'
The USGS dataset sample values were averaged by well after sAMlues to one half their detection
limit, in an effort to try to avoid unnecessary spatial bias in sites sampled more frequently. Sites where
all the values in the average calculation were non -detects were considered non -detects for plotting
purposes.
For percentile calculations and plotting, all non -detect values for a given analyte were set to the lowest
non -detect value in that dataset. This ensured non -detect samples would be the top (highest) ranks for
the percentile calculation. This was necessary because they cannot be assumed to be greater than any
detected value.

100%
90%
80%
70%
60%
c
50%
L
40%
30%
20%
10%
0%
10
Site Background Wells/Private Wells for Mayo - Boron (Unfiltered)
Site Background Wells Boron pg/L n = 70
Private Wells Boron pg/L n = 2
Site Background Wells Non -detect
Private Wells Non -detect
NC 2L Standard, 700 fag/L
100
Concentration pg/L
1000

Site Background Wells/USGS Wells/Private Wells for Mayo - Sulfate (Unfiltered)
• Site Background Wells Sulfate mg/L n = 70
• USGS Wells Sulfate, Averaged by Location mg/L n =60
Private Wells Sulfate mg/L n = 2
Site Background Wells Non -detect
USGS Wells Non -detect
Private Wells Non -detect
100%
90%
80%
70%
60%
a�
c
50%
a
40%
30%
20%
10%
cr-?
0%
0.01 0.10
NG 2L Standard, 25U
1.00
10.00
Concentration mg/L
100.00 1000.00

100%
90%
80%
70%
60%
a�
40%
30%
20%
10%
0%
Site Background Wells/USGS Wells/Private Wells for Mayo - Arsenic (Unfiltered)
• Site Background Wells Arsenic pg/L n = 70
• USGS Wells Arsenic, Averaged by Location pg/L n =122
Private Wells Arsenic pg/L n = 2
Site Background Wells Non -detect
USGS Wells Non -detect
Private Wells Non -detect
NC 2L Standard, 10 /L
g • ® r
i •
n�
I-;
•
ty =
4,
0.01 0.10 1.00 10.00
Concentration pg/L
100.00 1000.00

100%
90%
80%
70%
60%
a�
40%
30%
20%
10%
0%
Site Background Wells/USGS Wells/Private Wells for Mayo - Iron (Unfiltered)
• Site Background Wells Iron pg/L n = 70
• USGS Wells Iron, Averaged by Location pg/L n =2221
Private Wells Iron pg/L n = 2
Site Background Wells Non -detect
USGS Wells Non -detect
Private Wells Non -detect
NC 2L Standard, 300 p/L
• • ••
Z
s•
i
•
0.1 1.0 10.0 100.0 1000.0
Concentration pg/L
10000.0 100000.0 1000000.0

100%
90%
80%
70%
60%
a�
50%
a
40%
30%
20%
10%
0%
Site Background Wells/USGS Wells/Private Wells for Mayo - Manganese (Unfiltered)
• Site Background Wells Manganese fag/L n = 70
• USGS Wells Manganese, Averaged by Location pg/L n =813
Private Wells Manganese pg/L n = 2
Site Background Wells Non -detect
USGS Wells Non -detect
Private Wells Non -detect
NC 2L Standard, 50 /L
•
:i
0.01 0.10 1.00 10.00 100.00
Concentration pg/L
1000.00 10000.00 100000.00

100%
90%
80%
70%
60%
50%
o_
40%
30%
20%
10%
0%
1
Site Background Wells/USGS Wells/Private Wells for Mayo - Barium (Unfiltered)
Site Background Wells Barium lag/L n = 70
USGS Wells Barium, Averaged by Location lag/L n =77
Private Wells Barium lag/L n = 2
Site Background Wells Non -detect
USGS Wells Non -detect
Private Wells Non -detect
10
INU zL z:)tanaara, tuu
100
Concentration lag/L
1000
10000

100%
90 %
80 %
70 %
60%
a�
40%
30
20%
10%
0%
0.01
Site Background Wells/USGS Wells/Private Wells for Mayo - Chromium (Unfiltered)
• Site Background Wells Chromium pg/L n = 70
• USGS Wells Chromium, Averaged by Location pg/L n =124
Private Wells Chromium pg/L n = 2
Site Background Wells Non -detect
USGS Wells Non -detect
Private Wells Non -detect
NU 1L Standard, 10
0.10 1.00 10.00 100.00 1000.00
Concentration pg/L

100%
90%
80%
70 %
60%
a�
40%
30%
20%
10%
0%
Site Background Wells/USGS Wells/Private Wells for Mayo - Antimony (Unfiltered)
• Site Background Wells Antimony pg/L n = 70
• USGS Wells Antimony, Averaged by Location pg/L n =61
Private Wells Antimony pg/L n = 2
Site Background Wells Non -detect
USGS Wells Non -detect
Private Wells Non -detect
NC IMAC Standard, 1 /L
•
•
•
• i•
•
•
•
0
00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0.01
0.10
Concentration pg/L
1.00
10.00

100%
90 %
80 %
70 %
60%
a�
40%
30
20%
10%
0%
0.1
Site Background Wells/Private Wells for Mayo - Vanadium (Unfiltered)
• Site Background Wells Vanadium pg/L n = 38
Private Wells Vanadium pg/L n = 1
Site Background Wells Non -detect
Private Wells Non -detect
NC IMAC Standard, 0.3 pg/L
•
1.0
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Concentration pg/L
•
10.0
100.0

100%
90%
80%
70%
60%
a�
40%
30%
20%
10%
0%
0.1
Site Background Wells/USGS Wells/Private Wells for Mayo - Cobalt (Unfiltered)
• Site Background Wells Cobalt pg/L n = 40
• USGS Wells Cobalt, Averaged by Location pg/L n =2
Private Wells Cobalt pg/L n = 2
Site Background Wells Non -detect
USGS Wells Non -detect
Private Wells Non -detect
NC IMAC Standard, 1 /L
•
•
•
•
•
•
1.0
Concentration pg/L
10.0

100%
90%
80%
70%
60%
a�
50%
a
40%
30%
20%
10%
0%
Site Background Wells/USGS Wells/Private Wells for Mayo - pH
• Site Background Wells pH n = 59
• USGS Wells pH, Averaged by Location n =875
Private Wells pH n = 2
Site Background Wells Non -detect
USGS Wells Non -detect
Private Wells Non -detect
N[; 91 gtgn(iqrd R 5 - R 5
01
�• • •
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
• •
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
2 4
6
8
10
12
14
16
18
20
pH

100%
90%
80%
70%
60%
a�
40%
30%
20%
10%
0%
Site Background Wells/USGS Wells/Private Wells for Mayo - Total Dissolved Solids (Filtered)
• Site Background Wells Total Dissolved Solids mg/L n = 70
• USGS Wells Dissolved solids, Averaged by Location mg/L n =2014
Private Wells Total Dissolved Solids mg/L n = 2
Site Background Wells Non -detect
USGS Wells Non -detect
Private Wells Non -detect
1
10
100
1000
Concentration mg/L
10000
100000

Appendix D
Natural Attenuation — Ash Basins to
Compliance Boundary

2.2- bV6VD06nr oe 8F b22OCIVIE2' INC'
Appendix D Explanation Sheet
Box plots were created for boron, sulfate, arsenic, iron, manganese, vanadium, barium, chromium,
antimony, cobalt, pH, and total dissolved solids (TDS) to illustrate concentration changes that occur from
the ash basins to the compliance boundary. Box plots were created for ash pore -water data, wells within
the waste boundary, and wells outside the waste boundary but within the compliance boundary. Any
sample event in which boron was not detected (>50 ug/L) was excluded from the analysis since it would
not be indicative of groundwater impacted by the ash basins.
For comparison purposes box plots of the Site background data, private drinking water supply well (<0.5
mile radius from site), and USGS data are included, even if boron was not detected during the sampling
event. The Site background and USGS data are included in the illustration for comparison and are
referenced in Appendix C. Ash porewater, inside waste boundary, and outside waste boundary groups
only included concentrations if boron was detected (>50 ug/L) at that well for the sample date.
Estimated values (J qualifier) were omitted from the analysis for the private well data. Groups in which
samples have been screened for boron detects are colored differently from groups which use all sample
results regardless if boron was detected. The box plots were constructed to show the median with the
upper and lower "hinges" corresponding to the first and third quartiles (25th and 75th percentiles).
Values for non -detects are set at half of the detection limit. All data analyzed for unfiltered samples to
allow for comparison to the 2L standards and IMAC. The exception is for TDS which requires filtration.
The box plots contain two categories of six groups, and are defined as follows:
Wells with boron detected > 50 ug/L in sample
Ash Porewater — Wells screened within the ash
Inside Waste Boundary— Wells screened below the ash, within the waste boundary
Outside Waste Boundary — Wells screened outside the waste boundary, downgradient from ash
All wells, regardless if boron was detected in sample
Site Background — Wells screened outside compliance boundary, up -gradient of ash basin
Private Water Supply — All private drinking wells samples within 0.5-mile radius of the Site'
USGS Groundwater— North Carolina USGS well data'
The following table is a list of all Site wells used for the box plot analysis and which group they were
sorted in. No wells were excluded from the private water supply data or USGS groundwater.
' https://ncdenr.s3.amazonaws.com/s3fs-public/document-
libra ry/Full%20WeII%20Water%20Testing%20Res ults%20For%20Posting%208.20.pdf
Z http://nwis.waterdata.usgs.gov/nwis/qwdata queried downloaded on 6/10/2016 and included all data from
North Carolina for the analytes listed above

2.2- bV6VD06nr oe 8F b22OCIb.LE2' INC'
Mayo Box Plot Well Group List
All Wells
Wells
with Boron > 50 ug/L
Background
Porewater
Inside Waste
Outside Waste
BG-1
ABMW-1
ABMW-2BR
CW-1
BG-2
ABMW-2
ABMW-3S
CW-11D
MW-10BR
ABMW-3
ABMW-4BR
CW-2
MW-11BR
ABMW-4
ABMW-4D
CW-21D
MW-12D
MW-12S
MW-14BR
ABMW-2BRL
CW-3
CW-4
CW-5
CW-6
MW-13BR
MW-16BR
MW-16D
MW-16S
MW-2
MW-3
MW-3BR
M W-4
MW-5BR
MW-7BR
MW-7D
MW-8BR
MW-9BR

Antimony (Unfiltered) - Mayo
C
O
U
C
O
30 -
•
•
■
0-
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=44 n=70 n=61
Sample Location Type. Red Line: NC IMAC Standard (1 ug/L)
10.0 — •
N _
U
Cn '
i�
O -
J
I
J -
C
O
U
C 0.1 —
U
Ash Porewater
n=16
•
4
I I I I
Inside Waste Outside Waste Site Groundwater Private Wells
Boundary Boundary Background n=2
n=8 n=44 n=70
Sample Location Type. Red Line: NC IMAC Standard (1 ug/L)
USGS
Groundwater
n=61

Arsenic (Unfiltered) - Mayo
J
1000 -
750 -
250 -
0
C
O _
M
a
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells
n=16 Boundary Boundary Background n=2
n=8 n=44 n=70
Sample Location Type. Red Line: NC 2L Standard (10 ug/L)
USGS
Groundwater
n=122
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=44 n=70 n=122
Sample Location Type. Red Line: NC 2L Standard (10 ug/L)

Barium (Unfiltered) - Mayo
WIC
C
O
U
C
� j 500 -
0-
ROOM
Ash Porewater
n=16
Inside Waste
Outside Waste
Site Groundwater Private Wells
USGS
Boundary
Boundary
Background n=2
Groundwater
n=8
n=44
n=70
n=77
Sample Location Type. Red Line:
NC 2L Standard (700 ug/L)
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells
n=16 Boundary Boundary Background n=2
n=8 n=44 n=70
Sample Location Type. Red Line: NC 2L Standard (700 ug/L)
USGS
Groundwater
n=77

Boron (Unfiltered) - Mayo
7500 -
J
0 5000 -
C
O
U
C
O
U
2500 -
0-
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells
n=16 Boundary Boundary Background n=2
n=8 n=44 n=70
Sample Location Type. Red Line: NC 2L Standard (700 ug/L)
10000 —
N
U _
U)
0)
O
J
J _
1
C
O
1 100 — •
C -
U
C -
O _
U
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells
n=16 Boundary Boundary Background n=2
n=8 n=44 n=70
Sample Location Type. Red Line: NC 2L Standard (700 ug/L)

Chromium (Unfiltered) - Mayo
250 -
200 -
J
0 150-
C
O
c
1100 -
C
0
U
.ON
0-
1P
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=44 n=70 n=124
Sample Location Type. Red Line: NC 2L Standard (10 ug/L)
100 —
N
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells
n=16 Boundary Boundary Background n=2
n=8 n=44 n=70
Sample Location Type. Red Line: NC 2L Standard (10 ug/L)
•
USGS
Groundwater
n=124

Cobalt (Unfiltered) - Mayo
15-
c
CD
U
C
0
5-
1
0-
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=18 n=40 n=2
Sample Location Type. Red Line: NC IMAC Standard (1 ug/L)
T
•
•
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells
n=16 Boundary Boundary Background n=2
n=8 n=18 n=40
Sample Location Type. Red Line: NC IMAC Standard (1 ug/L)
USGS
Groundwater
n=2

Iron (Unfiltered) - Mayo
3e+05 -
2e+05 -
C
O
U
C
U 1 e+05 -
Oe+00
1e+05
N
U
O
J
' 1e+03 —
1
i
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=44 n=70 n=2221
Sample Location Type. Red Line: NC 2L Standard (300 ug/L)
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=44 n=70 n=2221
Sample Location Type. Red Line: NC 2L Standard (300 ug/L)

Manganese (Unfiltered) - Mayo
30000 -
20000 - _
J
1
C
O
C
CD
U
C •
O •
U 10000 - s•
i
•
• i
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=44 n=70 n=813
Sample Location Type. Red Line: NC 2L Standard (50 ug/L)
10000 —
a)
U
O
J -
100 =
c
O '
a> =
U -
C
O _
U
1—
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=44 n=70 n=813
Sample Location Type. Red Line: NC 2L Standard (50 ug/L)

pH (Unfiltered) - Mayo
12.5 -
a3
c
7.5 -
0
U Ow
IN
am
A
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells
n=8 Boundary Boundary Background n=2
n=4 n=42 n=59
Sample Location Type. Red Line: NC 2L Standard (6.5 - 8.5)
USGS
Groundwater
n=875
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=8 Boundary Boundary Background n=2 Groundwater
n=4 n=42 n=59 n=875
Sample Location Type. Red Line: NC 2L Standard (6.5 - 8.5)

Sulfate (Unfiltered) - Mayo
250
200 -
J
E 150 -
0
L
0 100 -
0
U
.�
m
a> _
M
U _
U)
0)
O
J
J -
E -
C _
O
M
0 =
U -
C -
O
•
•
•
•
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=44 n=70 n=60
Sample Location Type. Red Line: NC 2L Standard (250 mg/L)
Ash Porewater
n=16
Inside Waste Outside Waste Site Groundwater Private Wells
Boundary Boundary Background n=2
n=8 n=44 n=70
Sample Location Type. Red Line: NC 2L Standard (250 mg/L)
•
•
USGS
Groundwater
n=60

Total Dissolved Solids (Filtered) - Mayo
25000 -
20000 - 8
1
J
0 15000 - •
O
io •
i
C
chi 10000 -
c
O =
U
5000 -
0- •
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=44 n=70 n=2014
Sample Location Type. Red Line: NC 2L Standard (500 mg/L)
10000 —
a>
M
U
U)
0)
O
J
J
E
C
O
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells USGS
n=16 Boundary Boundary Background n=2 Groundwater
n=8 n=44 n=70 n=2014
Sample Location Type. Red Line: NC 2L Standard (500 mg/L)

Vanadium (Unfiltered) - Mayo
300 -
200
0)
C
O •
c
CD
U
C
O
U
100 - •
0
0111,
Ash Porewater Inside Waste Outside Waste Site Groundwater Private Wells
n=16 Boundary Boundary Background n=1
n=8 n=16 n=38
Sample Location Type. Red Line: NC IMAC Standard (0.3 ug/L)
Ash Porewater Inside Waste Outside Waste Site Groundwater
n=16 Boundary Boundary Background
n=8 n=16 n=38
Sample Location Type. Red Line: NC IMAC Standard (0.3 ug/L)
Private Wells
n=1