Cliffside_NEBA_CommunityImpactAnalysis_2018115

Community Impact Analysis
of Ash Basin Closure Options
at the Cliffside Steam Station

1805958.000 - 2920

Community Impact Analysis of
Ash Basin Closure Options at the
Cliffside Steam Station

Prepared on behalf of Duke Energy Carolinas,
LLC

Prepared by

Dr. Ann Michelle Morrison
Exponent
1 Mill & Main Place, Suite 150
Maynard, MA 01754

November 15, 2018

 Exponent, Inc.

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Contents
Page
List of Figures iv
List of Tables v
Acronyms and Abbreviations vii
Limitations viii
Executive Summary ix
1 Qualifications 1
2 Assignment and Retention 3
3 Reliance Materials 4
4 Introduction 5
4.1 Site Setting 6
4.2 Closure of the Ash Impoundments at CSS 10
5 Approach to Forming Conclusions 15
5.1 Net Environmental Benefit Analysis 17
5.2 Linking Stakeholder Concerns to NEBA 19
5.3 NEBA Risk Ratings 25
5.4 Risk Acceptability 26
6 Summary of Conclusions 28
7 Conclusion 1: All closure options for the CSS ash basins are protective of human
health. 30
7.1 Private water supply wells pose no meaningful risk to the community around CSS. 30
7.2 CCR constituents from the CSS ash basins pose no meaningful risk to human
populations. 32
7.3 NEBA – Protection of Human Health from CCR Exposure 36
8 Conclusion 2: All closure options for the CSS ash basins are protective of
ecological health. 37

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8.1 No meaningful risks to ecological receptors from CCR exposure exist under
current conditions or any closure option. 37
8.2 NEBA – Protection of Environmental Health from CCR Exposure 41
9 Conclusion 3: All closure options for the CSS ash basins create similar levels of
disturbance to communities. 43
9.1 There is no meaningful risk from diesel emissions to people living and working
along the transportation corridor. 46
9.2 The likelihood of noise, traffic, and accidents from transportation activities is
similar under all closure options. 50
9.2.1 Noise and Congestion 51
9.2.2 Traffic Accidents 51
9.3 NEBA – Minimize Human Disturbance 52
10 Conclusion 4: Most closure options for the CSS ash basins produce no net
environmental disturbance. 56
10.1 Most closure options produce net gains in environmental services. 58
10.2 NEBA – Minimize Environmental Disturbance 63
11 Conclusion 5: Most closure options for the CSS ash basins produce comparable
environmental services. 65
12 References 68

Appendix A Curriculum vitae of Dr. Ann Michelle Morrison, Sc.D.
Appendix B Human Health and Ecological Risk Assessment Summary Update for Cliffside
Steam Station
Appendix C Exposure Modeling and Human Health Risk Assessment for Diesel Emissions
Appendix D Habitat Equivalency Analysis
Appendix E Net Environmental Benefit Analysis

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List of Figures
Page
Figure 4-1. Map of CSS. Reproduced and adapted from Figure 2-1 of the 2018 CSA
Supplement (SynTerra 2018a). 7
Figure 4-2. Forest, field, scrub/shrub, and open water habitat at CSS, September 6,
2018. 9
Figure 4-3. Elemental composition of bottom ash, fly ash, shale, and volcanic ash. 10
Figure 8-1. Exposure areas evaluated in the 2018 Ecological Risk Assessment update. 40
Figure 9-1. Normalized differences between all offsite transportation activities under
combinations of CIP, excavation, and hybrid options. 46
Figure 10-1. Map of habitat types currently present at CSS 57

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List of Tables
Page
Table 4-1. Ash basin closure options provided by Duke Energy 12
Table 4-2. Overview of some key logistical differences between closure options for the
CSS Unit 5 inactive and active ash basins. 13
Table 5-1. Relationships between environmental services and concerns to the local
community associated with CCR and ash basin closure hazards 21
Table 5-2. Associations between objectives for closure and remediation of the CSS ash
basins and environmental services 22
Table 5-3. Matrix of key environmental services, attributes, and comparative metrics
applied in the NEBA 23
Table 5-4. Risk-ranking matrix for impacts and risk from remediation and closure
activities. 26
Table 7-1. Summary of human health risk assessment hazard index (HI) and excess
lifetime cancer risk (ELCR) from SynTerra (2018b) 33
Table 7-2. Summary of relative risk ratings for attributes that characterize potential
hazards to humans from CCR exposure in drinking water, surface water,
groundwater, soil, sediment, food, and through recreation 36
Table 8-1. Summary of relative risk rating for attributes that characterize potential
hazards to ecological resources from CCR exposure in surface water, soil,
sediment, and food 41
Table 9-1. Summary of offsite transportation logistics associated with each closure
option (Duke Energy 2018) 45
Table 9-2. Hazard indices (HI) and excess lifetime cancer risk (ELCR) from exposure
to diesel exhaust emissions along transportation corridors near CSS. 49
Table 9-3. Comparative metrics for increased noise and congestion and traffic accidents 52
Table 9-4. Summary of relative risk rating for attributes that characterize potential
hazards to communities during remediation activities. 54
Table 10-1. Summary of NPP DSAYs for closure options (Unit 5 Inactive Basin
Closure/Active Basin Closure) 62
Table 10-2. Percent impact of ash basin closure options. 63
Table 10-3. Summary of relative risk ratings for habitat changes that affect provision of
environmental services. 64

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Table 11-1. NEBA for closure of the ash basin at CSS. 67

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Acronyms and Abbreviations
AADT annual average daily traffic
AOW area of wetness
ASOS Automated Surface Observing S ystem
BCF bioconcentration factor
CAMA North Carolina Coal Ash Management Act
CAP corrective action plan
CCP coal combustion products
CCR coal combustion residuals
CCR Rule EPA Coal Combustion Residuals Rule of 2015
CERCLA Comprehensive Environmental Response, Compensation and Liability
Act
CIP cap in place
COI constituent of interest
COPC chemical of potential concern
CSA comprehensive site assessment
CSS Cliffside Steam Station
DPM diesel particulate matter
Duke Energy Duke Energy Carolinas, LLC
DSAY discounted service acre-year
ELCR excess lifetime cancer risk
EPA U.S. Environmental Protection Agency
ERA ecological risk assessment
HEA habitat equivalency analysis
HHRA human health risk assessment
HI hazard index
HQ hazard quotient
LOAEL lowest-observed-adverse-effects level
MOVES Mobile Vehicle Emissions Simulator
NEBA net environmental benefit analysis
NCDEQ North Carolina Department of Environmental Quality
NCDOT North Carolina Department of Transportation
NOAA National Oceanic and Atmospheric Administration
NOAEL no-observed-adverse-effects level
NPDES National Pollutant Discharge Elimination System
NPP net primary productivity
NRDA natural resource damage assessment
OSAT-2 Operational Science Advisory Team-2
RCRA Resource Conservation and Recovery Act
REL reference exposure level
RfD reference dose
SOC Special Order by Consent
TRV toxicity references value
TVA Tennessee Valley Authority

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Limitations
This report sets forth my conclusions, which are based on my education, training, and
experience; field work; established scientific methods; and information reviewed by me or
under my direction and supervision. These conclusions are expressed to a reasonable degree of
scientific certainty. The focus of this report is on local community impacts. I have, therefore, not
attempted to evaluate broader environmental impacts, such as impacts from greenhouse gas
emissions, that would be associated with each closure option.
The conclusions in this report are based on the documents made available to me by Duke
Energy or collected as part of my investigation. I reserve the right to supplement my
conclusions if new or different information becomes available to me. As an example, the
excavation option presented in this report assumes that landfilling of excavated ash can be
accommodated within the boundaries of the currently permitted landfill space. The currently
permitted landfill space was sized to accommodate future ash production and did not include the
addition of excavated ash from the Cliffside Steam Station (CSS) ash basins. If additional
landfill space is required to accommodate both excavated ash and future ash production, then
additional habitat destruction would be necessary, and that impact has not been factored into this
analysis.

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Executive Summary1
In 2015, the U.S. Environmental Protection Agency (EPA) issued a rule called the “Hazardous
and Solid Waste Management System; Disposal of Coal Combustion Residuals [CCR] from
Electric Utilities” (CCR Rule), which, among other things, regulates closure of coal ash
impoundments in the United States. Closure of coal ash impoundments in North Carolina is
further regulated by the North Carolina Coal Ash Management Act of 2014 (CAMA) as
amended by H.B. 630, Sess. L. 2016-95. Under both the North Carolina CAMA and the federal
CCR Rule, there are two primary options for closure of an ash impoundment:
 “Cap in place” (CIP) closure involves decanting the impoundment and
placing a low-permeability liner topped by appropriate cap material, soil, and
grass vegetation over the footprint of the ash to restrict vertical transport of
water through the ash, as well as a minimum of 30 years of post-closure care,
which requires the implementation of corrective action measures if and as
necessary;
 Excavation closure involves decanting the impoundment, excavating all ash
in the basin, transporting the ash to an appropriate, permitted, lined landfill,
and restoring the site.
Duke Energy Carolinas, LLC’s (Duke Energy’s) Cliffside Steam Station (CSS), also known as
the Rogers Energy Complex, has historically had two unlined, onsite inactive ash basins (Units
1–4 inactive ash basin and Unit 5 inactive ash basin) and one unlined, onsite active ash basin.
Ash from the Units 1–4 ash basin has been completely excavated, and the area repurposed,
while the Unit 5 inactive ash basin has been covered with a layer of topsoil and vegetation
(SynTerra 2018a). Two unlined dry ash storage areas are also located within the active ash
basin. Duke Energy operates a separate onsite, lined landfill, the Coal Combustion Products
(CCP) Landfill, at CSS.

1 Note that this Executive Summary does not contain all of the technical evaluations and analyses that support the
conclusions. Hence, the main body of this report is at all times the controlling document.

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Duke Energy has evaluated two representative closure options for the Unit 5 inactive ash
basin—CIP and excavation. Three representative closure options have been evaluated by Duke
Energy for the active ash basin—CIP, excavation to an onsite landfill, and hybrid closure—the
latter of which involves excavating and consolidating ash within the basin footprint to reduce
the spatial area of CIP closure. I have evaluated every combination of those closure options for
each basin. The administrative process for selecting an appropriate closure plan for the ash
basins is ongoing.
The purpose of my report is to examine how the local community’s environmental health and
environmental services2 are differently affected by each closure option as currently defined and
to evaluate these differences in a structured framework that can support decision-making in this
matter.
Environmental Decision-Making
Environmental decision-making involves understanding complex issues that concern multiple
stakeholders. Identifying the best management alternative often requires tradeoffs among
stakeholder values. These tradeoffs necessitate a transparent and systematic method to compare
alternative actions and support the decision-making process. My analyses in this matter have
used a net environmental benefit analysis (NEBA) framework (Efroymson et al. 2003, 2004) to
compare the relative risks and benefits from CIP closure, excavation closure, or a hybrid CIP
and excavation closure of the ash basins at CSS. The NEBA framework relies on scientifically
supported estimates of risk to compare the reduction of risk associated with chemicals of
potential concern (COPCs)3 under different remediation and closure alternatives alongside the
creation of any risk during the remediation and closure, providing an objective, scientifically
structured foundation for weighing the tradeoffs between remedial and closure alternatives.

2 Environmental services, or ecosystem services, are ecological processes and functions that provide value to
individuals or society (Efroymson et al. 2003, 2004).
3 COPCs are “any physical, chemical, biological, or radiological substance found in air, water, soil or biological
matter that has a harmful effect on plants or animals”
(https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?de
tails=&glossaryName=Eco%20Risk%20Assessment%20Glossary).

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Despite the scientific basis of the risk characterization process used in NEBA, stakeholders in
any environmental decision-making scenario may place different values on different types of
risk (i.e., stakeholders may have different priorities for the remediation and closure). NEBA
does not, by design, elevate, or increase the value of, any specific risk or benefit in the
framework. The purpose of NEBA is to simultaneously and systematically examine all tradeoffs
that affect the services provided to humans and the ecosystem by the environment under
remediation and closure, allowing decision-makers to more fully understand all potential
benefits and risks of each alternative.
NEBA and similar frameworks have been used extensively by regulatory agencies such as the
National Oceanic and Atmospheric Administration (NOAA) and EPA to support evaluating
tradeoffs in mitigation (e.g., NOAA 1990), remediation (e.g., U.S. EPA 1988, 1994), and
restoration (e.g., NOAA 1996). The National Environmental Policy Act (40 CFR § 1502) relies
on a structured framework to conduct environmental assessments and produce environmental
impact statements; these analyses evaluate potential adverse effects from development projects
and identify alternatives to minimize environmental impacts and/or select mitigation measures.
Natural resource damage assessment (NRDA) utilizes a structured process to estimate
environmental injury and lost services and to identify projects that restore the impacted
environment and compensate the public for the lost environmental services (e.g., NOAA 1996).
The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
remedial investigation/feasibility study process uses a set of evaluation criteria to identify
remediation projects for contaminated sites that meet remediation objectives for effectiveness,
implementability, and cost (U.S. EPA 1988). Within the Superfund Program, EPA has also
recognized the importance of remediation that comprehensively evaluates cleanup actions “to
ensure protection of human health and the environment and to reduce the environmental
footprint of cleanup activities to the maximum extent possible” (U.S EPA 2010).
The Tennessee Valley Authority (TVA) recently used a structured framework to compare the
impacts and benefits of ash basin closure alternatives at ten of its facilities (TVA 2016).
Through a NEBA-like analysis, the TVA identified “issue areas,” such as air quality,
groundwater, vegetation, wildlife, transportation, and noise, and created a summary table that

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provided a side-by-side comparison of the impacts of “no action,” “closure-in-place,” and
“closure-by-removal” actions. As a result of this analysis, TVA identified “closure-in-place” as
“its preferred alternative” for all ten facilities stating, “[t]his alternative would achieve the
purpose and need for TVA’s proposed actions and compared to Closure-by-Removal with less
environmental impact, shorter schedules, and less cost” (TVA 2016). The CSS ash basin closure
presents similar “issue areas” that can benefit from a similar, systematic analysis of net benefits
resulting from closure activities.
Linking Stakeholder Concerns to NEBA
To better understand stakeholder concerns related to closure of the ash basin at CSS, I reviewed
written communications about ash pond closure plans for CSS submitted to and summarized by
the North Carolina Department of Environmental Quality (NCDEQ 2016). From this review, I
identified the following categories of stakeholder concerns:
 Drinking water quality
 Groundwater quality
 Surface water quality
 Fish and wildlife
 Maintaining property value
 Preservation of natural beauty
 Recreational value
 Swimming safety
 Failure of the ash impoundment
 Risk created by the closure option outweighing risk from contamination.
The primary concerns expressed by community stakeholders involve perceived risks from
exposure to CCR constituents that could negatively affect environmental services that benefit
the local community: provision of safe drinking water and food, safe recreational enjoyment
(hunting, fishing, swimming), and protection of natural beauty and biodiversity.4 Potential

4 Biodiversity is the variety of plants and animals present at a location. Protection of biodiversity refers to
provision of habitat and related functions capable of sustaining biological populations.

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hazards to the community associated with closure activities include physical disturbance of
existing habitats; air pollution from diesel emissions resulting from transportation activities; and
traffic, noise, and accidents that could result in property damage, injuries, and fatalities. Table
ES-1 links concerns over CCR exposure and potential hazards created by ash basin closure to
environmental services that could be affected by closure activities.

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xiv
Table ES-1. Relationships between environmental services and concerns to the local community associated with CCR
and ash basin closure hazards
Environmental Services
Safe drinking
water quality
Safe surface
water quality
Safe air
quality
Safe food
quality
Protection of
biodiversity
Recreation Natural
beauty
Safe community
environment
CCR Concerns
Drinking water
contamination
X X X
Groundwater contamination X X X
Surface water
contamination
X X X X X X X
Fish/wildlife contamination X X X X X
Contamination impacting
property value
X X X X X X X
Contamination impacting
natural beauty
X X X
Contamination impacting
recreational enjoyment
X X X X X
Contamination impacting
swimming safety
X X X X
Failure of the ash
impoundment
X X X X X X X
Closure Hazards
Habitat loss X X X X X
Contamination of air X X X X
Noise, Traffic, Accidents X X

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In recognition of the potential discrepancy between stakeholder priorities and the broad and
balanced treatment of service risks and benefits in NEBA, I organized the NEBA analysis
around the following five objectives for ash basin closure that recognize stakeholder concerns
while being consistent with the methods and purpose of NEBA:
1. Protect human health from CCR constituent exposure
2. Protect ecological health from CCR constituent exposure
3. Minimize risk and disturbance to humans from closure
4. Minimize risk and disturbance to the local environment from closure
5. Maximize local environmental services.
In my analysis, I linked environmental services to the local community that could be potentially
impacted by ash basin closure and the identified objectives of ash basin closure, and I identified
attributes and comparative metrics5 that characterize the condition of the environmental services
(Efroymson et al. 2003, 2004).
I used human health attributes (e.g., risk to onsite construction workers, risk to offsite
swimmers) and risk quotients (hazard index [HI], excess lifetime cancer risk [ELCR]) to
evaluate whether there would be a potential impact to environmental services related to safe
water, air, and food under each ash basin closure option. I also used human health attributes to
evaluate whether there would be an impact to air quality during closure activities. I used
ecological health attributes (e.g., risk to birds, mammals) and risk quotients (hazard quotients
[HQs]) to evaluate whether there would be a potential impact to environmental services related
to safe surface water and food and protection of biodiversity and natural beauty under the ash
basin closure options. I evaluated risk and disturbance associated with traffic and accidents
using transportation metrics and trucking logistics (e.g., number of truck miles driven)
associated with each closure option to evaluate potential impacts to community safety. I used
net primary productivity (NPP)6 and discounted service acre-years (DSAYs)7 to characterize

5 For purposes of this analysis, an attribute is a feature that characterizes environmental services and may be
impacted by a closure option. Comparative metrics are features of the attribute (e.g., risk quotients, acreage of
habitat) that can be measured and compared between alternatives.
6 NPP represents the mass of chemically fixed carbon produced by a plant community during a given time
interval. It reflects the rate at which different ecosystems are able to sequester carbon, which is related to
mitigating climate change (https://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOD17A2_M_PSN).

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differences in the environmental services that derive from habitats (e.g., protection of
biodiversity, natural beauty) and that would be impacted by ash basin closure activities. Finally,
I assembled all attributes, services, and objectives within a full NEBA to examine which of the
closure options best maximizes environmental services for the local community. The metrics I
used are scientifically appropriate and commonly applied metrics to evaluate risk to humans and
the environment (U.S. EPA 1989, 1997, 2000; NHTSA 2016) and to quantitatively measure
differences in environmental services associated with impact and restoration (Dunford et al.
2004; Desvousges et al. 2018; Penn undated; Efroymson et al. 2003, 2004).
Of note, my analysis did not consider the risks involved with onsite construction activities. For
example, I did not attempt to evaluate occupational accidents created by onsite construction and
excavation. Nor did I attempt to evaluate emissions associated with onsite construction
activities. Finally, I did not attempt to consider the risk created by disturbing the ash basin and
exposing it to the elements during excavation activities.
Some stakeholders also expressed concern over safety of the ash impoundment dam (NCDEQ
2016). The most recent dam safety report produced by Amec Foster Wheeler (2018) and
submitted to NCDEQ indicates “the construction, design, operation, and maintenance of the
CCR surface impoundments have been sufficiently consistent with recognized and generally
accepted engineering standards for protection of public safety and the environment” (Browning
and Thomas 2018).
Several possible options for closure of the ash basin at CSS were identified by Duke Energy and
summarized in (Table ES-2). I used these options in the NEBA to examine how different
closure possibilities impact environmental services to the local community.

7 DSAYs are derived from habitat equivalency analysis (HEA). HEA is an assessment method that calculates
debits based on services lost and credits for services gained from a remediation action (Dunford et al. 2004;
Desvousges et al. 2018; Penn undated). A discount rate is used to standardize the different time intervals in
which the debits and credits occur, and in doing so, present the service debits and credits at present value. The
present value of the services is usually expressed in terms of discounted service acre-years of equivalent habitat,
or DSAYs, which provide a means to compare the different service levels of affected habitat acres (Dunford et
al. 2004; Desvousges et al. 2018; Penn undated).

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Table ES-2. Ash basin closure options provided by Duke Energy (2018)
Closure Option
Unit 5/Active Basins Description
Closure
Duration
(years)a,c
Construction
Duration
(years)b,c
CIP/CIP CIP both Unit 5 and active ash
basins
6 3
CIP/Excavation CIP Unit 5 basin; excavate active
basin to an onsite landfill
9 6
CIP/Hybrid CIP Unit 5 basin; partially excavate
to consolidate ash and CIP
consolidated ash
8 5
Excavation/CIP Excavate Unit 5 basin; CIP active
basin
6 3
Excavation/Excavation Excavate both Unit 5 and active ash
basins
9 6
Excavation/Hybrid Excavate Unit 5 basin; partially
excavate to consolidate ash and
CIP consolidated ash
8 5
a Includes pre-design investigation, design and permitting, site preparation, construction, and site restoration.
b Includes only site preparation, construction, and site restoration.
c Duration estimates assume simultaneous closure of the Unit 5 and active ash basins. A construction feasibility analysis
of this assumption has not been conducted. If the basins were to be closed sequentially, the duration of the estimated
closure for each option would be substantially longer.
NEBA Risk Ratings
NEBA organizes environmental hazard and benefit information into a unitless metric that
represents the degree and the duration of impact from remediation and closure alternatives. One
approach to structure this analysis is to create a risk-ranking matrix that maps the proportional
impact of a hazard (i.e., risk) with the duration of the impact, which is directly related to the
time to recovery (Robberson 2006). The risk-ranking matrix used for this application of NEBA
is provided in Table ES-3. In this application, the matrix uses alphanumeric coding to indicate
the severity of an impact: higher numbers and higher letters (e.g., 4F) indicate a greater extent
and a longer duration of impact. Shading of cells within the matrix supports visualization of the
magnitude of the effect according to the extent and duration of impact.8 When there is no
meaningful risk, the cell is not given an alphanumeric code. Relative risk ratings for each
attribute and option examined were assembled into objective-specific summaries to compare the

8 Categories and shading as defined in the risk-ranking matrix are based on best professional judgment and used
for discussion of the relative differences in relative risk ratings. Alternative risk matrices and resulting NEBA
classifications are explored in Appendix E.

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net benefits of the closure options. All closure options in the NEBA were evaluated against
current conditions as a “baseline” for comparison.
Table ES-3. Risk-ranking matrix for impacts and risk from closure activities.
Darker shading and higher codes indicate greater impact.

Duration of Impact (years)
10–15
(4)
5–9
(3)
1–4
(2)
<1
(1) % Impact No meaningful risk -- -- -- --
<5% (A) 4A 3A 2A 1A
5–19% (B) 4B 3B 2B 1B
20–39% (C) 4C 3C 2C 1C
40–59% (D) 4D 3D 2D 1D
60–79% (E) 4E 3E 2E 1E
>80% (F) 4F 3F 2F 1F
NEBA analysis of possible closure options for the ash basin at CSS helps both Duke Energy and
other stakeholders understand the net environmental benefits from the closure option
configurations that were examined. If a closure option that is preferred for reasons not
considered in the NEBA does not rate as one of the options that best maximizes environmental
services to the local community, closure plans for that option can be re-examined, and
opportunities to better maximize environmental benefits can be identified (e.g., including an
offsite habitat mitigation project to offset environmental services lost from habitat alteration).
The NEBA can then be re-run with the updated plan to compare the revised closure plan with
other closure options.
The following is a summary of my conclusions and supporting analyses, which are structured
around the five objectives identified above.
Conclusion 1: All closure options for the CSS ash basins are
protective of human health.
The first objective for ash basin closure, to protect human health from CCR constituent
exposure, is represented by environmental services that provide safe drinking water, safe

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groundwater, safe surface water, safe food consumption, and safe recreation. For purposes of the
NEBA, these safety considerations were evaluated based on the following:
1. Provision of alternate drinking water supplies to public and private well water
supply users within a 0.5-mile radius of CSS (Holman 2018);
2. Concentrations of CCR constituents of interest (COIs)9 in drinking water
wells that could potentially affect local residents and visitors, as characterized
by HDR (2015a) and SynTerra (2018a) in the Comprehensive Site
Assessment (CSA); and
3. Risk to various human populations from CCR exposure, as characterized in
the updated human health and ecological risk assessment conducted by
SynTerra (2018b; Appendix B).
Based on these analyses, no CCR impacts to drinking water and no meaningful risk to humans
from CCR exposure were found under current conditions10 or under any closure option. Using
the NEBA framework and relative risk ratings, these results are summarized in Table ES-4
within the objective of protecting human health from exposure to CCR constituents.

9 COIs are constituents relevant to analysis of potential exposure to CCR constituents but are not necessarily
associated with risk to human or ecological receptors.
10 SynTerra’s updated human health risk assessment (HHRA) considered only potential exposure pathways that
currently exist and could remain after ash basin closure under any closure option. Any potential risk currently
associated with seeps (or areas of wetness [AOWs]) at CSS was not evaluated in the HHRA or considered in this
analysis because any risk resulting from seeps will be eliminated, reduced, or mitigated per the court-enforceable
Special Order by Consent (SOC) that Duke entered with the North Carolina Environmental Management
Commission on April 18, 2018 (EMC SOC WQ S17-009; See Section 4.2). The SOC requires Duke Energy to
accelerate the schedule for decanting the ash basin to “substantially reduce or eliminate” seeps that may be
affecting state or federal waters; the SOC also requires Duke Energy to take appropriate corrective actions for any
seeps remaining after decanting is complete to ensure the remaining seeps are managed “in a manner that will be
sufficient to protect public health, safety, and welfare, the environment, and natural resources” (EMC SOC WQ
S17-009).

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Table ES-4. Summary of relative risk ratings for attributes that characterize potential
hazards to humans from CCR exposure in drinking water, surface water,
groundwater, food, and recreation
Objective Protect Human Health from CCR
Hazard Exposure to CCR Potentially Affected Populations Local Residents/Visitors Onsite Construction Workers Offsite Recreational Swimmers Offsite Recreational Waders Offsite Recreational Boaters Offsite Recreational Fishers Offsite Subsistence Fishers Scenario (Unit 5/Active ash basin closure option)
Baseline -- -- -- -- -- -- --
CIP/CIP -- -- -- -- -- -- --
CIP/Excavation -- -- -- -- -- -- --
CIP/Hybrid -- -- -- -- -- -- --
Excavation/CIP -- -- -- -- -- -- --
Excavation/Excavation -- -- -- -- -- -- --
Excavation/Hybrid -- -- -- -- -- -- --
“--” indicates “no meaningful risk.”
Current conditions and conditions under all closure options support provision of safe drinking
water, safe surface water, safe food, and safe recreation, satisfying the first objective of ash
basin closure—to protect human health from CCR constituent exposure.
Conclusion 2: All closure options for the CSS ash basins are
protective of ecological health.
The second objective for ash basin closure, to protect ecological health from CCR constituent
exposure, is represented by environmental services that provide safe surface water, safe food
consumption, and protection of biodiversity and natural beauty. For purposes of the NEBA,
these considerations were evaluated based on the following:

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1. Risk to ecological receptors from CCR exposure, as characterized by
SynTerra (2018b; Appendix B) in the updated human health and ecological
risk assessment; and
2. Aquatic community health in the Broad River as reported in the 2010
environmental monitoring report (Coughlan et al. 2010).
From my review of these analyses, no evidence of impacts to ecological receptors from CCR
exposure was identified under current conditions11 or under any closure option, and the Broad
River continues to support a healthy aquatic community. Using the NEBA framework and
relative risk ratings, these results are summarized in Table ES-5 within the objective of
protecting ecological health from exposure to CCR constituents.
Current conditions and conditions under all closure options support provision of safe surface
water, safe food consumption, and protection of biodiversity and natural beauty, satisfying the
second objective of ash basin closure—to protect ecological health from CCR constituent
exposure.

11 SynTerra’s updated ecological risk assessment (ERA) considered only potential exposure pathways that currently
exist and could remain after ash basin closure under any closure option. Any potential risk currently associated
with seeps (or AOWs) at CSS was not evaluated in the ERA or considered in this analysis because any risk
resulting from seeps will be eliminated, reduced, or mitigated per the court-enforceable SOC that Duke entered
with the North Carolina Environmental Management Commission on April 18, 2018 (EMC SOC WQ S17-009;
See Section 4.2). The SOC requires Duke Energy to accelerate the schedule for decanting the ash basin to
“substantially reduce or eliminate” seeps that may be affecting state or federal waters; the SOC also requires Duke
Energy to take appropriate corrective actions for any seeps remaining after decanting is complete to ensure the
remaining seeps are managed “in a manner that will be sufficient to protect public health, safety, and welfare, the
environment, and natural resources” (EMC SOC WQ S17-009).

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Table ES-5. Summary of relative risk ratings for attributes that characterize potential
hazards to ecological resources from CCR exposure in surface water, soil,
sediment, and food
Objective Protect Ecological Health from CCR
Hazard Exposure to CCR Potentially Affected Populations Fish Populations Aquatic Omnivore Birds (mallard) Aquatic Piscivore Birds (great blue heron) Aquatic Herbivore Mammals (muskrat) Aquatic Piscivore Mammals (river otter) Scenario (Unit 5/Active ash basin closure option)
Baseline -- -- -- -- --
CIP/CIP -- -- -- -- --
CIP/Excavation -- -- -- -- --
CIP/Hybrid -- -- -- -- --
Excavation/CIP -- -- -- -- --
Excavation/Excavation -- -- -- -- --
Excavation/Hybrid -- -- -- -- --
“--” indicates “no meaningful risk.”
Conclusion 3: All closure options for the CSS ash basins create
similar levels of disturbance to communities.
The third objective for ash basin closure, to minimize risk and disturbance to humans from
closure, is represented by environmental services that provide safe air quality and a safe
community environment. For purposes of the NEBA, these considerations were evaluated based
on the following:
1. Health risks from diesel exhaust emissions to the community living and
working along transportation corridors during trucking operations to haul

1805958.000 - 2920 xxiii
materials to and from the ash basin, as evaluated through the application of
diesel truck air emissions modeling and human health risk assessment; and
2. The relative risk for disturbance and accidents resulting from trucking
operations affecting residents living and working along transportation
corridors during construction operations, as evaluated by comparing the
relative differences in trucking operations between the closure options.
From these analyses, no meaningful health risk is expected from diesel exhaust emissions under
any closure option, but all closure options are expected to produce community disturbance in the
form of noise, traffic congestion, and risk of traffic accidents.
I used the number of trucks per day passing12 a receptor along a near-site transportation corridor
to examine the differences in noise and traffic congestion under the closure options. I compared
the increase in the average number of trucks hauling materials to CSS under the closure
options13 to the current number of truck passes for the same receptor. I specified a baseline level
of truck passes14 on the transportation corridor under current conditions of 97 passes per day.
Based on the assumed 97-truck-per-day baseline level and the number of truck trips per day
from Duke Energy’s projections (Duke Energy 2018), all options would have an impact of 15%
or less (CIP/CIP = 14%, CIP/Excavation = 9%, CIP/Hybrid = 9%, Excavation/CIP = 15%,
Excavation/Excavation = 9%, Excavation/Hybrid = 10%) on noise and traffic congestion. I
input these percent changes to the risk-ranking matrix (Table ES-3) along with the total duration
of trucking activities (Table ES-2) to evaluate which of the closure options best minimizes
human disturbances.

12 Truck passes per day resulting from closure activities are calculated as the total number of loads required to
transport earthen fill, geosynthetic materials, and other materials multiplied by two to account for return trips.
The resulting total number of passes is then divided evenly among the total number of mo nths of construction
time multiplied by 26 working days per month.
13 Truck trips to haul ash were not included in the estimate for CSS ash basin closure because trucks hauling ash
would not leave CSS property and would not affect community receptors along the transportation corridors.
14 A baseline estimate of trucking passes per day for transportation corridors near CSS was derived from North
Carolina Department of Transportation (NCDOT) data of annual average daily traffic (AADT) at thousands of
locations across the state and the proportion of road miles driven by large trucks in North Carolina (See
Appendix E for details).

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I also evaluated risk of traffic accidents by comparing the average number of annual offsite road
miles driven between closure options relative to an estimate of the current average road miles
driven in Rutherford and Cleveland Counties, North Carolina. I specified a current, or baseline,
level of annual road miles driven along the transportation corridor near CSS of 60.4 million
miles,15 and the road miles driven under the closure options are from the trucking projections
provided by Duke Energy (2018). Using the 60.4-million-truck-miles baseline assumption, all
closure options have a relative risk rating of <5% (CIP/CIP = 0.1%, CIP/Excavation = 0.05%,
CIP/Hybrid = 0.06%, Excavation/CIP = 0.11%, Excavation/Excavation = 0.06%,
Excavation/Hybrid = 0.07%). These relative risk ratings appear to be insensitive to lower
assumed baseline annual truck miles (Appendix E).
Table ES-6 summarizes the NEBA relative risk ratings based on the trucking projections and
implementation schedules provided by Duke Energy (2018) for the objective of minimizing
disturbance to humans during closure. Unlike the results from the evaluation of objectives 1 and
2 for ash basin closure, which showed no difference in environmental services under any closure
option, all closure options create disturbance and risk to human populations; however, the
cumulative impact to the community is relatively similar based on the trucking projections and
implementation schedules provided by Duke Energy (2018).

15 To estimate the number of baseline truck miles, I multiplied the number of total vehicle miles traveled in
Rutherford and Cleveland Counties (NCDMV 2017) by the average 6.9% contribution of trucks to total AADT
in Rutherford and Cleveland Counties (NCDOT 2015).

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Table ES-6. Summary of relative risk ratings for attributes that characterize
potential hazards to communities during closure activities.
Darker shading and higher codes indicate greater impact.
Objective Minimize Human Disturbance
Hazard
Noise and
Traffic
Congestion
Traffic
Accidents
Air
Pollution Potentially Affected Populations Local Residents/Visitors Local Residents/Visitors Reasonable Maximum Exposure Scenario (Unit 5/Active ash basin closure option)
Baseline baseline baseline baseline
CIP/CIP 2B 2A --
CIP/Excavation 3B 3A --
CIP/Hybrid 3B 3A --
Excavation/CIP 2B 2A --
Excavation/Excavation 3B 3A --
Excavation/Hybrid 3B 3A --
“--” indicates “no meaningful risk.”
All closure options support safe air quality from diesel truck emissions along the transportation
routes; however, each creates a comparable level of disturbance and risk that could adversely
impact community safety. Thus, all closure options similarly satisfy the third objective of ash
basin closure—to minimize risk and disturbance to humans from closure.16

16 If for any reason (e.g., safety of personnel at CSS), the basins cannot be closed simultaneously, the duration of
closure activities would be additive to an unknown degree for each basin, which has not been considered in my
analyses and may change risk ratings and NEBA conclusions.

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Conclusion 4: Most closure options for the CSS ash basins
produce no net environmental disturbance.
The fourth objective for ash basin closure, to minimize risk and disturbance to the local
environment from closure, is represented by two environmental services: protection of
biodiversity and natural beauty. For purposes of the NEBA, these considerations were evaluated
based on differences in the NPP of impacted habitats under the closure options, as estimated by
the number of DSAYs calculated by a habitat equivalency analysis (HEA).
The results of the HEA indicate that all but one closure option produce a net gain in
environmental services as indicated by a positive DSAY total. Only CIP closure of both ash
basins (CIP/CIP) results in a net loss of environmental services due primarily to reduced NPP
services provided by a grass cap,17 which adversely affects the level of environmental services
provided by the ash-impacted habitat such that environmental services produced after closure
will not compensate for the service losses resulting from the closure. The differences in NPP
services are summarized in Table ES-7. A full description of the methods, assumptions, results,
and sensitivity analyses for the HEA are provided in Appendix D and E.

17 An open field provides a relatively lower NPP service level than forest habitat (40% of for est NPP; Ricklefs
2008), and since a grass cap requires periodic maintenance mowing, for purposes of the HEA it was assumed
never to reach a level of NPP service equivalent to an open field. Grass cap was assigned a post-closure service
level of 8%, with full service attained in 2 years.

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xxvii
Table ES-7. Summary of NPP DSAYs for closure options (Unit 5 Inactive Basin Closure/Active Basin Closure)
CIP/CIP CIP/Excavation CIP/Hybrid Excavation/CIP Excavation/Excavation Excavation/Hybrid
Ash basin losses Open field −334 −334 −334 −334 −334 −334

Grass Cap −83 −83 −83 −101 −101 −101

Open Water −114 −114 −114 −113 −113 −113

Wetland
Broadleaf Forest −172 −172 −172 −181 −181 −181
Needleleaf Forest −79 −79 −79 −79 −79 −79
Scrub/Shrub −150 −150 −150 −205 −205 −205
Wetland Forest −24 −24 −24 −24 −24 −24

Total losses −955 −955 −955 −1,037 −1,037 −1,037
Ash basin post-closure gains Open field 53 53 53

Grass Cap 273 104 226 169 121

Open Water

Wetland
Broadleaf Forest 339 1541 617 1,126 2,329 1,404
Needleleaf Forest 116 528 211 385 797 481
Scrub/Shrub 82 82 82
Wetland Forest 3 16 6 12 24 14

Total gains 731 2,189 1,060 1,827 3,284 2,156
Landfill/borrow losses Forest −29 −1,200 −29 −556 −1,727 −556

Open field
Grass Cap −4 −4

Total losses −33 −1,200 -29 −560 −1,727 −556
Landfill/borrow post-closure gains Forest 23 23 23

Open Field
Grass Cap 3 75 42 114 39

Total gains 26 98 23 42 114 39
Net Gain/Loss per Option −231 132 99 272 634 601
Note: DSAYs for specific habitat types are reported here rounded to the nearest whole number. As such, the net gain/loss per option differs slightly from the sum of the individual
DSAYs reported in the table.
Closure duration estimates assume simultaneous closure of the EAB and WAB. A construction feasibility analysis of this assumption has not been conducted. If the basins were to be
closed sequentially, the duration of the estimated closure for each option would be substantially longer and change the results of the HEA.

1805958.000 - 2920 xxviii
The impact of closure on environmental services was computed as the percentage difference in
net DSAYs produced by the closure option and the baseline DSAYs (or the absolute value of
the DSAY losses). The DSAY losses represent the NPP services that would have been produced
by the ash basin, borrow areas, and landfills but for the project closure. The DSAY gains
represent the NPP services restored after project closure plus any future gains realized from
existing habitats before remediation begins. The sum of DSAY losses and gains represents the
net change of NPP services for the project resulting from closure. Dividing the closure option
net DSAYs by the absolute value of the DSAY losses provides a percentage of the impact. From
these calculations, CIP closure of both basins (CIP/CIP) will have a 23% impact, 18 while all
other closure options will have no net adverse impact on NPP services and will, in fact, increase
net NPP services. These percent impacts were input to the risk-ranking matrix (Table ES-3)
along with the duration of the closure activities (Table ES-2) to visualize, within the NEBA
framework, which of the closure options best minimizes environmental disturbances (Table ES-
8).
Within the objective of minimizing environmental disturbance from closure, my analyses
indicate that all but one closure option produce a net benefit in habitat-derived environmental
services; however, CIP closure of both basins (CIP/CIP) decreases habitat-derived
environmental services. Thus, all closure options except CIP/CIP satisfy the fourth objective of
ash basin closure—to minimize risk and disturbance to the local environment from closure.19

18 As discussed below, this habitat impact could be offset with an appropriate reforestation project.
19 If for any reason (e.g., safety of personnel at CSS), the basins cannot be closed simultaneously, the duration of
closure activities would be additive to an unknown degree for each basin, which has not been considered in my
analyses and may change risk ratings and NEBA conclusions.

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Table ES-8. Summary of relative risk ratings for habitat changes that
affect protection of biodiversity and natural beauty.
Darker shading and higher codes indicate greater impact.
Objective
Minimize Environmental
Disturbance
Hazard Habitat Change
Attribute DSAYs
Scenario (Unit 5/Active ash basin closure option
Baseline baseline
CIP/CIP 2C
CIP/Excavation --
CIP/Hybrid --
Excavation/CIP --
Excavation/Excavation --
Excavation/Hybrid --
“--” indicates “no meaningful risk.”
Conclusion 5: Most closure options for the CSS ash basins
produce comparable environmental services.
Identifying environmental actions that maximize environmental services (the fifth objective for
ash basin closure) is a function of NEBA (Efroymson et al. 2003, 2004) and the overarching
objective that encompasses each of the other four objectives and all of the environmental
services that have been considered to this point.
I organized my analyses around the following five objectives for ash basin closure, and I found
the following:
1. Protect human health from CCR constituent exposure
All closure options for the CSS ash basins are protective of human health.
2. Protect ecological health from CCR constituent exposure
All closure options for the CSS ash basins are protective of ecological health.
3. Minimize risk and disturbance to humans from closure
All closure options create similar levels of disturbance to communities.
4. Minimize risk and disturbance to the local environment from closure
Most closure options produce no net environmental disturbance.
5. Maximize environmental local services
Most closure options produce comparable environmental services.

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Table ES-9 summarizes the relative risk ratings for all attributes and objectives that have been
considered. From this analysis, which is based on a scientific definition of risk acceptability and
includes no value weighting, all closure options, with the exception of CIP closure of both
basins (CIP/CIP), produce comparable environmental benefits, similarly satisfying the fifth
objective of ash basin closure—to maximize local environmental services.
As noted previously, NEBA analysis provides an opportunity to better understand the net
environmental benefits of possible closure options. If Duke Energy’s preferred closure option
for reasons not considered in the NEBA does not best maximize environmental services to the
local community as currently defined, the NEBA results provide insight into how environmental
services could be improved for that closure option. For instance, if Duke Energy’s preferred
closure option for CSS is CIP closure of both basins but the HEA results for the currently
defined CIP closure option estimates a net environmental service loss of 231 DSAYs, Duke
Energy could consider incorporating into an updated CIP closure plan for CSS a mitigation
project that compensates for the net environmental service losses projected from the currently
defined CIP closure option. As an example, if Duke Energy started a reforestation project
outside of the ash basin in 2023 (when onsite preparation of the ash basins begins), the
reforestation project would gain 23.6 DSAYs/acre over the lifetime of the site (150 years in the
HEA), requiring an approximate 9.8 acre project to compensate for the 231 DSAY loss
projected in the HEA. Re-analysis of the HEA component of the NEBA for the updated possible
closure options would then result in no net environmental losses (as NPP services) from habitat
alteration of the basins for any currently defined closure options.
By looking at a wide variety of attributes that represent a number of different environmental
services that directly link to local stakeholder concerns for the CSS ash basins, I conclude, with
a reasonable degree of scientific certainty, that all closure options except CIP of both basins
(CIP/CIP) provide similar net environmental services and disturbance to the community and the
environment.20

20 If for any reason (e.g., safety of personnel at CSS), the basins cannot be closed simultaneously, the duration of
closure activities would be additive to an unknown degree for each basin, which has not been considered in my
analyses and may change risk ratings and NEBA conclusions.

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xxxi
Table ES-9. NEBA for closure of the ash basins at CSS.
Darker shading and higher alphanumeric codes indicate greater impact.
Objective Protect Human Health from
CCR
Protect Ecological Health from
CCR Minimize Human Disturbance
Minimize
Environmental
Disturbance
Hazard Exposure to CCR Exposure to CCR
Noise and
Traffic
Congestion
Traffic
Accidents
Air
Pollution Habitat Change Potentially Affected Populations Local Residents/Visitors Onsite Construction Workers Offsite Recreational Swimmers Offsite Recreational Waders Offsite Recreational Boaters Offsite Recreational Fishers Offsite Subsistence Fishers Fish Populations Aquatic Omnivore Birds (mallard) Aquatic Piscivore Birds (great blue heron) Aquatic Herbivore Mammals (muskrat) Aquatic Piscivore Mammals (river otter) Local Residents/Visitors Local Residents/Visitors Reasonable Maximum Exposure DSAYs
Scenario (Unit 5/Active ash basin closure option
Baseline -- -- -- -- -- -- -- -- -- -- -- baseline baseline baseline baseline
CIP/CIP -- -- -- -- -- -- -- -- -- -- -- 2B 2A -- 2C
CIP/Excavation -- -- -- -- -- -- -- -- -- -- -- 3B 3A -- --
CIP/Hybrid -- -- -- -- -- -- -- -- -- -- -- 3B 3A -- --
Excavation/CIP -- -- -- -- -- -- -- -- -- -- -- 2B 2A -- --
Excavation/Excavation -- -- -- -- -- -- -- -- -- -- -- 3B 3A -- --
Excavation/Hybrid -- -- -- -- -- -- -- -- -- -- -- 3B 3A -- --
“--” indicates “no meaningful risk.”

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1 Qualifications
I am a senior managing scientist in the Ecological and Biological Sciences Practice at Exponent,
a scientific and engineering consulting firm. I am a professional ecologist, toxicologist, and
biologist with more than 20 years of experience studying the relationship between human
activities and effects on natural resources and people. I have Doctor of Science and Master of
Science degrees in environmental health from the Harvard University School of Public Health. I
have a Bachelor of Science degree in biology from Rhodes College. My academic and
professional training includes a broad background in topics ranging from biology, ecology,
toxicology, epidemiology, pollution fate and transport, and statistical analysis. Key areas of my
practice involve the use of structured frameworks for evaluating multiple lines of evidence to
assess causation of environmental impacts and to weigh the benefits and consequences of
decisions that affect ecological and human health.
Decision support projects I have conducted include the following:
 Net environmental benefit analysis (NEBA) to facilitate the selection of a
remediation plan for a lead contaminated river and to support closure option
analysis for several coal ash basins;
 Developing beach management tools to improve public advisories related to
elevated fecal bacteria from sewage contamination at recreational beaches;
 Selecting cleanup thresholds for sediment remediation that quantitatively
weigh the tradeoff between sensitivity and specificity of potential thresholds
to meet cleanup objectives;
 Natural resource damage assessment (NRDA) to support injury quantification
and restoration selection; and
 Review and testimony on the sufficiency of environmental impact analysis to
support development planning.
Projects I have been involved in have concerned coal ash basin closures, oil spills, sewage
releases, heavy metal contamination, development planning, and various industrial and
municipal facilities that have generated complex releases to the aquatic environment. A list of

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my publications, presentations, and cases for which I have written expert reports, been deposed,
and/or provided trial testimony is provided in my curriculum vitae, included as Appendix A of
this report.

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2 Assignment and Retention
I was asked to examine how local environmental health and environmental services are
differently affected under potential closure options for the coal ash basins at Duke Energy
Carolinas, LLC’s (Duke Energy’s) Cliffside Steam Station (CSS) and to evaluate these
differences in a structured framework that can support decision-making. My assignment
included review of the comprehensive site assessment (CSA) and corrective action plan (CAP)
documents for CSS, as well as documents available through the North Carolina Department of
Environmental Quality’s (NCDEQ’s) website and documents prepared as part of Duke Energy’s
National Pollutant Discharge Elimination System (NPDES) permitting. I visited CSS on
September 6, 2018, and I reviewed expert reports prepared for related matters involving CSS. A
list of the primary documents I relied upon is provided in Section 3 of this report.

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3 Reliance Materials
In the process of conducting my analyses, I have reviewed many documents. Of those, I have
relied most on the following reports and documents. Technical (scientific literature) references
are cited in subsequent sections of this report and listed in Section 12.
 Comprehensive Site Assessment (CSA) for the Cliffside Steam Station, including all
updates (HDR 2015a, 2016b; SynTerra 2018a)
 Corrective Action Plan (CAP) for the Cliffside Steam Station, including all updates
(HDR 2015b, 2016a)
o Baseline Human Health and Ecological Risk Assessment for the Cliffside Steam
Station (HDR 2016c [Appendix F of CAP 2])
 2010 environmental monitoring report for the Broad River (Coughlan et al. 2010)
 North Carolina Department of Environmental Quality (NCDEQ) Rogers Meeting Officer
Report (NCDEQ 2016)
o Attachment V. Written Public Comments Received
o Attachment VIII. Public Comment Summary Spreadsheet
 Updated Baseline Human Health and Ecological Risk Assessment (SynTerra 2018b;
Appendix B)
 Closure logistics estimates (Duke Energy 2018).

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4 Introduction
In 2015, the U.S. Environmental Protection Agency (EPA) issued a rule called the “Hazardous
and Solid Waste Management System; Disposal of Coal Combustion Residuals [CCR] from
Electric Utilities” (CCR Rule), which, among other things, regulates closure of coal ash
impoundments in the United States. Closure of coal ash impoundments in North Carolina is
further regulated by the North Carolina Coal Ash Management Act of 2014 (CAMA), as
amended by H.B. 630, Sess. L. 2016-95. Under both the North Carolina CAMA and the federal
CCR Rule, there are two primary options for closure of an ash impoundment:
 “Cap in place” (CIP) closure involves decanting the impoundment and
placing a low permeability liner topped by appropriate cap material, soil, and
grass vegetation over the footprint of the ash to restrict vertical transport of
water through the ash, as well as a minimum of 30 years of post-closure care,
which requires the implementation of corrective action measures if and as
necessary;
 Excavation closure involves decanting the impoundment, excavating all ash
in the basin, transporting the ash to an appropriate, permitted, lined landfill,
and restoring the site.
Duke Energy has evaluated two representative closure options for the Unit 5 inactive ash
basin—CIP and excavation. Three representative closure options have been evaluated by Duke
Energy for the active ash basin—CIP, excavation to an onsite landfill, and hybrid closure—the
latter of which involves excavating and consolidating ash within the basin footprint to reduce
the spatial area of CIP closure. I have evaluated every combination of these closure options for
each basin. The administrative process for selecting an appropriate closure plan is ongoing.
The purpose of my report is to examine how the local community’s environmental health and
environmental services21 are differently affected by each closure option as currently defined and

21 Environmental services, or ecosystem services, are ecological processes and functions that provide value to
individuals or society (Efroymson et al. 2003, 2004).

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to evaluate these differences in a structured framework that can support decision-making in this
matter.
4.1 Site Setting
CSS is a coal-fired electricity generating facility in Rutherford and Cleveland counties in North
Carolina. CSS is located on the southern bank of the Broad River and is approximately 1,000
acres in area (HDR 2015a) (Figure 4-1).
CSS began operation in 1940 with Units 1–4. Unit 5 began operation in 1972, and Unit 6 in
2008. Historically, there were three ash basins at CSS: the currently inactive and excavated
Units 1–4 ash basin, the inactive Unit 5 ash basin, and the active ash basin (Figure 4-1).
Excavation of the Units 1–4 ash basin was completed in March 2017, with the excavated ash
moved to the onsite, lined, permitted Coal Combustion Products (CCP) landfill. Two lined
basins and a wastewater treatment plant are currently being constructed within the footprint of
the former Units 1–4 ash basin. The Unit 5 ash basin was retired in 1980 when it reached
capacity; it is currently covered with a layer of topsoil and vegetation and used as a lay down
area (SynTerra 2018a). The active ash basin was constructed in 1975 and currently receives
inflows from the Unit 5 fly ash and bottom ash handling systems, cooling tower blowdown,
stormwater runoff from yard drainage, coal pile runoff, gypsum pile runoff, limestone pile
runoff, landfill leachate, and wastewater streams from various sources on site (SynTerra 2018a).
An unlined dry ash storage area is located within and beyond the northwestern portion of the
active ash basin boundary. Ash produced by Unit 6 is currently dry-handled and deposited in the
onsite CCP landfill. The Unit 5 inactive ash basin contains approximately 806,000 tons of ash,
and the active ash basin contains approximately 5,400,000 tons of ash (SynTerra 2018a).
Effluent from CSS’s active ash basin is discharged under NPDES (NPDES Outfall 002) to the
Broad River, which flows to the north of CSS (Figure 4-1).

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7

Figure 4-1. Map of CSS. Reproduced and adapted from Figure 2-1 of the 2018 CSA Supplement (SynTerra 2018a).
The location of ash basin discharge to the Broad River was added (NPDES outfall 002).

1805958.000 - 2920 8
CSS is located in an ecological transitional zone between the Appalachian Mountains and the
Atlantic coastal plain.22 Historically, much of the region was transformed from oak-hickory-pine
forests to farmland and more recently from farmland back to woodlands characterized by
successional pine and hardwood forest (Griffith et al. 2002). I observed forest, field,
scrub/shrub,23 and open water habitat areas onsite during my September 6, 2018 visit (Figure
4-2).
The area surrounding CSS consists of the Broad River, undeveloped land, and residential
properties (SynTerra 2018a). The Broad River is described as offering “miles of gentle white
water, class I and II rapids, in the southern part of Rutherford County.”24 The Broad River
Paddle Trail, developed by the Rutherford Outdoor Coalition, covers 41 miles and includes 12
trail segments starting at the Lake Lure Dam upstream of CSS and ending at the Broad River
Greenway downstream of CSS.25 Public fishing and paddling access is available at the U.S.
Highway 221-A bridge over the Broad River on Duke Energy property; primary fished species
at this location include largemouth bass (Micropterus salmoides), muskellunge (stocked; Esox
masquinongy),26 redbreast sunfish (Lepomis auratus), smallmouth bass (Micropterus dolomieu),
and white bass (Morone chrysops).27 Images of the Broad River adjacent to CSS are shown in
Figure 4-2.

22 CSS is located in the Southern Outer Piedmont based on EPA’s ecoregion classification system.
https://www.epa.gov/eco-research/ecoregions
23 Scrub/shrub habitat is characterized by low, woody plants.
24 http://www.lakelureland.com/rutherford_county/rutherford_county_nc_lakes_rivers.htm
25 http://www.rutherfordoutdoor.org/trails/board -river-paddle-trail
26 Muskellunge are not stocked in the Broad River. The North Carolina Wildlife Resources Commission stocks
muskellunge in the French Broad, Nolichucky, and New rivers as well as Lake Adger, an impoundment on the
Green River, which merges with the Broad River upstream of CSS (N.C. Wildlife Resources Commission
2010).
27 https://www.ncpaws.org/wrcmapbook/FishingAreas.aspx

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Figure 4-2. Forest, field, scrub/shrub, and open water habitat at CSS, September 6, 2018.
(a) Forest with scrub/shrub habitat looking north toward the active ash basin. (b)
Forest, field, scrub/shrub, and open water habitat looking southeast over the
western portion of the active ash basin from the dry ash storage area. (c) Two
white tail deer (Odocoileus virginianus) and a turkey (Meleagris gallopavo
silvestris) at the edge of forest habitat west-northwest of the active ash basin
near the Broad River. (d) Forest and open water habitat at the eastern portion of
the active ash basin, looking southeast from the north dam adjacent to the
Broad River. (e) Forest and open water habitat along Suck Creek, which flows
through CSS to the north and drains into the Broad River. (f) Broad River at
NPDES Outfall 002.

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4.2 Closure of the Ash Impoundments at CSS
Coal ash, or CCR, includes fly ash, bottom ash, boiler slag, and flue gas desulfurization material
(U.S. EPA 2017c). CCR are derived from the inorganic minerals in coal, which include quartz,
clays, and metal oxides (EPRI 2009). Fine-grained, amorphous particles that travel upward with
flue gas are referred to as fly ash, while the coarser and heavier particles that fall to the bottom
of the furnace are called bottom ash (EPRI 2009). The chemical composition of coal ash is
similar to natural geologic materials found in the earth’s crust, but the physical and chemical
properties of coal ash vary depending on the coal source and the conditions of coal combustion
and cooling of the flue gas (EPRI 2009). The majority of both fly ash and bottom ash are
composed of silicon, aluminum, iron, and calcium, similar to volcanic ash and shale (Figure
4-3). Trace elements such as arsenic, cadmium, lead, mercury, selenium, and chromium
generally constitute less than 1% of total CCR composition (EPRI 2009; USGS 2015). CCR are
classified as a non-hazardous solid waste under the Resource Conservation and Recovery Act
(RCRA).28

Figure 4-3. Elemental composition of bottom ash, fly ash, shale, and volcanic ash.
Excerpt from EPRI (2009).

28 https://www.epa.gov/coalash/coal-ash-rule

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EPA’s 2015 CCR Rule (40 CFR §§ 257 and 261) requires groundwater monitoring29 of CCR
landfills and surface impoundments and for corrective action, including closure, of CCR sites
under certain circumstances. Owners and operators of CCR landfills and impoundments that are
required to be closed under the regulation must conduct an analysis of the effectiveness of
potential corrective measures (a corrective measures assessment) and select a strategy that
involves either excavation or capping the “waste-in-place.” Per § 257.97(b), the selected
strategy must at a minimum be protective of human health and the environment, attain
groundwater protection standards, control the source of releases so as to reduce or eliminate
further releases of certain CCR constituents into the environment, remove from the environment
as much of the contaminated material that was released from the CCR unit as is feasible, taking
into account factors such as avoiding inappropriate disturbance of sensitive ecosystems, and
comply with the standards for management of wastes in § 257.98(d).
The CCR Rule does not provide criteria for selecting between these closure options because
they are both considered effective closure methods. The CCR Rule states both methods of
closure “can be equally protective, provided they are conducted properly.” Hence, the final CCR
Rule allows the owner or operator to determine whether excavation or closure in place is
appropriate for their particular unit (80 FR 21412).
For the last several years, Duke Energy has been evaluating all of its ash impoundments and
remains in the midst of further evaluating each one, including at CSS, under the CCR Rule and
pursuant to the administrative process set forth in CAMA. Ultimately, a final closure plan will
be approved by NCDEQ.
Multiple possible options for closure of the active and inactive ash basins at CSS were identified
by Duke Energy and are summarized in (Table 4-1). These options were used in the NEBA to

29 According to the CCR Rule, groundwater must be evaluated for boron, calcium, fluoride, pH, sulfate, and total
dissolved solids, which are defined as the constituents for detection monitoring in Appendix III of the Rule.
When a statistically significant increase in Appendix III constituents over background concentrations is
detected, monitoring of assessment monitoring constituents (Appendix IV) is required. Assessment monitoring
constituents are antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, fluoride, lead, lithium,
mercury, molybdenum, selenium, t hallium, and radium 226 and 228, combined.

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examine how different closure possibilities impact environmental services to the local
community.
Table 4-1. Ash basin closure options provided by Duke Energy
Closure Option
(Unit 5/Active) Unit 5 Inactive Basin Active Basin
Closure
Duration
(years)a,c
Construction
Duration
(years)b,c
CIP/CIP CIP CIP 6 3
CIP/Excavation CIP Excavate to onsite
landfill
9 6
CIP/Hybrid
CIP
Partially excavate to
consolidate ash and CIP
consolidated ash
8 5
Excavation/CIP Excavate to onsite
landfill CIP 6 3
Excavation/Excavation Excavate to onsite
landfill
Excavate to onsite
landfill
9 6
Excavation/Hybrid Excavate to onsite
landfill
Partially excavate to
consolidate ash and CIP
consolidated ash
8 5
a Includes pre-design investigation, design and permitting, site preparation, construction, and site restoration.
b Includes only site preparation, construction, and site restoration.
c Duration estimates assume simultaneous closure of the Unit 5 and active ash basins. A construction feasibility analysis of th is
assumption has not been conducted. If the basins were to be closed sequentially, the duration of the estimated closure for each
option would be substantially longer.
Table 4-2 provides a summary of some of the logistical differences between the closure options.
Key among these are the following: (1) a longer period is necessary to complete most
excavation closures and (2) substantially more deforestation is required under closures including
excavation.30 Considering logistics alone, however, does not provide a complete understanding
of the potential benefits and hazards associated with each closure option, and an integrated
analysis is necessary to place stakeholder concerns regarding risk from CCR in the larger
context of risks and benefits to environmental services.

30 CSS has onsite and planned lined landfills that could accept some excavated ash from the CSS ash basins;
however, there is insufficient capacity in the currently configured landfill to accept all of the coal ash from the
ash basins under an excavation closure. Forest would need to be cleared to expand the landfill capacity to create
this capacity. Deforestation is also likely under a CIP closure to access surface soil fo r capping activities.

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Table 4-2. Overview of some key logistical differences between closure
options for the CSS Unit 5 inactive and active ash basins.
Data provided by Duke Energy.
Closure Option
(Unit 5/Active)
Closure Completion
Time (years)a
Deforested
Acresb
Truck
trips/dayc
Total truck
milesd
CIP/CIP 6 1 7 192,015
CIP/Excavation 9 41 4 195,615
CIP/Hybrid 8 1 4 181,962
Excavation/CIP 6 19 7 208,701
Excavation/Excavation 9 59 5 212,301
Excavation/Hybrid 8 19 5 198,648
a Includes pre-design investigations, design and permitting, site preparation, construction, and site restoration.
b Includes areas deforested to create borrow pits and/or landfill. Assumes simultaneous closure of the EAB and WAB.
A construction feasibility analysis of this assumption has not been conducted. If the basins were to be closed
sequentially, the duration of the estimated closure for each option would be substantially longer.
c Includes the total number of offsite roundtrip truck trips to haul earthen, and geosynthetic material to and from the ash
basin.
d Includes the total number of truck miles driven over the duration of construction operations to haul material to and
from the ash basin.
Closure of the ash basin at CSS involves decanting any overlying water in the basin and
excavating or capping in place the underlying ash, as specified under CAMA and the federal
CCR Rule. Additional activities related to, but separate from, closure under CAMA and the
CCR Rule concern constructed31 and non-constructed32 seeps associated with the ash basin.33 A
Special Order by Consent (SOC; EMC SOC WQ S17-009) was signed by the North Carolina
Environmental Management Commission and Duke Energy on April 18, 2018, to “address
issues related to the elimination of seeps” from Duke Energy’s coal ash basins. The SOC
requires Duke Energy to accelerate the schedule for decanting the ash basin to “substantially
reduce or eliminate” seeps that may be affecting state or federal waters; the SOC also requires
Duke Energy to take appropriate corrective actions for any seeps remaining after decanting is
complete to ensure the remaining seeps are managed “in a manner that will be sufficient to

31 Constructed seeps are features within the dam structure, such as toe drains or filter blankets, that collect seepage
of liquid through the dam and discharge the seepage through a discrete, identifiable point source to a receiving
water; Seep S-104 and S-106 are the only constructed seeps at CSS, and they are now incorporated into the CSS
NPDES permit NC0005088 and managed as part of the wastewater treatment system at CSS (NCDEQ 2018).
32 Non-constructed seeps are not on or within the dam structure and do not convey liquid through a pipe or
constructed channel; non-constructed seeps at CSS that require monitoring (and potentially action if they are not
eliminated after ash basin decanting) are listed in the SOC (EMC SOC WQ S17 -009).
33 In 2014, Duke Energy provided a comprehensive evaluation of all areas of wetness (AOWs or seeps) on Duke
Energy property and formally applied for NPDES coverage for all seeps (EMC SOC WQ S17 -009).

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protect public health, safety, and welfare, the environment, and natural resources” (EMC SOC
WQ S17-009). Given the court-enforceable requirement for Duke Energy to remediate any
seeps remaining after decanting the ash basin to meet standards for the protection of public and
environmental health, for purposes of my analyses, seeps (or areas of wetness [AOWs]) are
assumed to contribute no meaningful risk to humans or the environment following any closure
option since all closure options will entail decanting the basins and remediating any risk
associated with remaining seeps as required by the SOC (EMC SOC WQ S17-009).

1805958.000 - 2920 15
5 Approach to Forming Conclusions
Environmental decision-making involves understanding complex issues that concern multiple
stakeholders. Identifying the best management option often requires tradeoffs among
stakeholder values. For example, remediation management alternatives can decrease potential
risks to human health and the environment from contaminants, but such benefits can also have
unintended consequences, such as adverse impacts to other functions of the environment (e.g.,
destruction of habitat) or create other forms of risk (e.g., contamination of other environmental
media). These tradeoffs between existing and future environmental services necessitate a
transparent and systematic method to compare alternative actions and support the decision-
making process.
Structured frameworks or processes are commonly used to weigh evidence and support
requirements for environmental decision-making. Examples include:
 Environmental assessment (EA) and environmental impact statement (EIS)
process that supports National Environmental Policy Act requirements for
evaluating impacts from development projects and selecting mitigation
measures (40 CFR § 1502);
 Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) remedial investigation/feasibility study process that characterizes
risk from contaminants at a site and then evaluates remediation alternatives
(U.S. EPA 1988);
 RCRA corrective measures study that supports identification, development,
and evaluation of potential remedial alternatives for corrective action (U.S.
EPA 1994);
 EPA’s causal analysis/diagnosis decision information system (CADDIS) that
supports stressor identification and selection of appropriate mitigation actions
under the Clean Water Act (Cormier et al. 2000);

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 NRDA that characterizes injury and lost human services to support selection
of restoration projects under a number of environmental laws, including
CERCLA and the Oil Pollution Act of 1990 (e.g., NOAA 1996); and
 NEBA that evaluates the tradeoffs in environmental impacts and benefits
from remediation alternatives (NOAA 1990; Efroymson et al. 2003, 2004).
These frameworks have different regulatory origins and somewhat different approaches to
accomplishing their specific objectives, but they all rely on a common core of analyses,
including characterization of exposures, identification of adverse effects, definition of complete
pathways between exposures and effects, characterization of risk or impact to exposed receptors
(i.e., human and ecological populations), and weight-of-evidence analysis.
My analyses in this matter have used a NEBA framework to compare the relative risks and
benefits derived from the closure options under consideration for the ash basins at CSS. NEBA
was originally developed to examine impacts and benefits to ecological resources and habitats
excluding impacts and risk to humans (Efroymson et al. 2004); however, as noted by EPA
(2009), remediation and closure actions can also have both direct and indirect consequences to
humans. To support a more thorough analysis of the net benefits of each closure option in this
matter, I have included comparative analyses in the NEBA that consider environmental health
more broadly, including risks and benefits to both ecological and human populations in the
vicinity. My analyses draw on the core principles of the environmental decision support
frameworks discussed above and follow a pragmatic and transparent process.
In assembling information for the NEBA and forming my conclusions, I have relied on analyses
reported in the CSA and CAP documents, as well as information provided by Duke Energy.
Because a NEBA of environmental health necessarily encompasses a variety of scientific
disciplines, I assembled a team of professionals within Exponent with expertise in ecological
risk assessment (ERA), human health risk assessment (HHRA), contaminant fate and transport,
decision support analysis, and statistics to review documents and, where indicated, conduct
analyses at my direction. The results of these efforts are included in this report and have been
reviewed by me.

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5.1 Net Environmental Benefit Analysis
Net environmental benefits are defined as “the gains in environmental services or other
ecological properties attained by remediation or ecological restoration, minus the environmental
injuries caused by those actions” (Efroymson et al. 2003, 2004). Environmental services, or
ecosystem services, are ecological processes and functions that produce value to individuals or
society. A NEBA, as discussed above, is a structured framework for comparing impacts and
benefits to environmental services and support decision-making (Efroymson et al. 2003, 2004).
NEBA can be useful in evaluating and communicating the short-term and long-term impacts of
remedial alternatives options but does not make a determination of which alternative one is best;
that decision must be made by stakeholders and decision-makers and may ultimately involve
weighing or prioritizing some values or objectives over others (Efroymson et al. 2003, 2004).
NEBA relies on scientifically supported estimates of risk to compare the reduction of risk
associated with chemicals of potential concern (COPCs) 34 under different remediation and
closure alternatives alongside the creation of any risk during the remediation and closure,
providing an objective, scientifically structured foundation for weighing the tradeoffs among
remedial and closure alternatives. Despite the scientific basis of the risk characterization
process, however, stakeholders in any environmental decision-making scenario may place
different values on different types of risk. In other words, stakeholders may have different
priorities for the remediation and closure. NEBA does not, by design, elevate, or increase the
value of, any specific risk or benefit in the framework. The purpose of NEBA is to
simultaneously and systematically examine all tradeoffs that affect the services (e.g., provision
of safe drinking water, protection of biodiversity35) provided to humans and the ecosystem by
the environment under remediation and closure, allowing decision-makers to more fully
understand all potential benefits and risks of each alternative.

34 COPCs are “any physical, chemical, biological, or radiological substance found in air, water, soil or biological
matter that has a harmful effect on plants or animals”
(https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?de
tails=&glossaryName=Eco%20Risk%20Assessment%20Glossary).
35 Biodiversity is the variety of plants and animals present at a location. Protection of biodiversity refers to
provision of habitat and related functions capable of sustaining biological populations.

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EPA supports the use of NEBA (U.S. EPA 2009) as a means to compare remediation and
redevelopment alternatives “based on their contributions to human well-being.” EPA and the
National Oceanic and Atmospheric Administration (NOAA) also use NEBA to support oil spill
response decision-making (Robberson 2006; NOAA 1990). Examples of NEBA in oil-spill
decision-making include:
 Exxon Valdez Oil Spill: NEBA was first applied to weigh the net
environmental benefits of rock-washing to remove beached oil versus leaving
the oil in place to naturally degrade (NOAA 1990).
 Deepwater Horizon Oil Spill: NEBA was used by the Operational Science
Advisory Team-2 (OSAT-2) to “compare the environmental consequences of
the defined cleanup endpoints for the oil and beach types considered, and the
consequences of cleanup beyond those endpoints,” specifically noting, “It is
at this juncture that the concept of continued remedial efforts doing ‘more
harm than good’ becomes a concern” (OSAT 2011).
I have personally applied NEBA to evaluate the net environmental benefits associated with two
alternative sediment remediation cleanup goals for lead contamination in a tidal river. At that
site, the river had been contaminated with lead from a battery manufacturing facility, and the
state required removal of contaminated sediment that could potentially pose a health risk to
people and the environment. The responsible party conducted human and ecological risk
assessments, toxicity tests, and benthic community analyses to support the selection of an
appropriate cleanup threshold for lead that would be protective of humans and the natural
environment. Uncertainty in the results, however, led to two different remediation threshold
concentrations being proposed by the state and by the responsible party. The NEBA was
conducted to examine the tradeoffs in environmental impacts associated with the two cleanup
thresholds. For one segment of the river, the footprint of remediation, including the size and
types of habitat impacted, was substantially different under the alternative cleanup goals. The
lower remediation threshold caused much greater impacts to submerged aquatic vegetation and
riparian (shoreline) habitat that had cascading consequences to animals that rely on those
environments. NEBA was able to demonstrate that remediation to the lower threshold would
cause greater ecological harm and disturbance to the local community with little or no decrease

1805958.000 - 2920 19
in risk to benthic invertebrates (the ecological receptor at issue).36 Consequently, the higher
remediation goal was applied to that segment of the river.
These examples of NEBA are particularly relevant to the issues at CSS. Remediation and
closure of coal ash basins is specifically addressed in CAMA and the CCR Rule, and both CIP
and excavation closure satisfy defined cleanup endpoints. At issue is whether removal of the
coal ash under an excavation closure crosses the “juncture,” as noted by OSAT-2, where the
action would do more harm than good (OSAT 2011).
5.2 Linking Stakeholder Concerns to NEBA
To better understand stakeholder concerns related to closure of the ash basins at CSS, I
reviewed written communications about ash basin closure plans for CSS submitted to and
summarized by NCDEQ (NCDEQ 2016). From this review, I identified the following categories
of stakeholder concerns:
 Drinking water quality
 Groundwater quality
 Surface water quality
 Fish and wildlife
 Maintaining property value
 Preservation of natural beauty
 Recreational value
 Swimming safety
 Failure of the ash impoundment
 Risk created by the closure option outweighing risk from contamination.
The primary concerns expressed by community stakeholders involve perceived risks from
exposure to CCR constituents that could negatively affect environmental services that benefit
the community: provision of safe drinking water and food, safe recreational enjoyment (e.g.,

36 Both remediation goals were found to be protective of human, fish, bird, and mammal health. Uncertain ty in
toxicity test results and concern for protection of benthic macroinvertebrates (e.g., insect larvae and
crustaceans) led the state to propose a lower remediation threshold for lead.

1805958.000 - 2920 20
hunting, fishing, swimming), protection of natural beauty, and biodiversity. Potential hazards to
the community associated with closure activities include physical disturbance of existing
habitats; air pollution from diesel emissions; and traffic, noise, and accidents that could result in
property damage, injuries, and fatalities. Table 5-1 links concerns over CCR exposure and
potential hazards created by ash basin closure to environmental services that could be affected
by closure activities.

1805958.000 - 2920
21
Table 5-1. Relationships between environmental services and concerns to the local community associated with CCR
and ash basin closure hazards
Environmental Services
Safe drinking
water quality
Safe surface
water quality
Safe air
quality
Safe food
quality
Protection of
biodiversity
Recreation Natural
beauty
Safe community
environment
CCR Concerns
Drinking water
contamination
X X X
Groundwater contamination X X X
Surface water
contamination
X X X X X X X
Fish/wildlife contamination X X X X X
Contamination impacting
property value
X X X X X X X
Contamination impacting
natural beauty
X X X
Contamination impacting
recreational enjoyment
X X X X X
Contamination impacting
swimming safety
X X X X
Failure of the ash
impoundment
X X X X X X X
Closure Hazards
Habitat alteration X X X X X
Contamination of air X X X X
Noise, Traffic, Accidents X X

1805958.000 - 2920 22
In recognition of the potential discrepancy between stakeholder priorities and the broad and
balanced treatment of service risks and benefits in NEBA, I organized the NEBA in this matter
around the following five objectives for ash basin closure that recognize stakeholder concerns
while being faithful to the methods and purpose of NEBA:
1. Protect human health from CCR constituent exposure
2. Protect ecological health from CCR constituent exposure
3. Minimize risk and disturbance to humans from closure
4. Minimize risk and disturbance to the local environment from closure
5. Maximize local environmental services.
Associations between environmental services to the local community that could be potentially
impacted by ash basin closure and the identified objectives of ash basin remediation are shown
in Table 5-2.
Table 5-2. Associations between objectives for closure and remediation of the CSS
ash basins and environmental services
Ash Basin Closure Objectives
Environmental
Services
Protect
human health
from CCR
constituent
exposure
Protect
ecological health
from CCR
constituent
exposure
Minimize risk
and
disturbance
to humans
from closure
Minimize risk
and disturbance
to the local
environment
from closure
Maximize local
environmental
services
Safe drinking
water quality X X X
Safe surface
water quality X X X
Safe air quality X X
Safe food quality X X X
Recreation X X
Natural beauty X X X
Protection of
biodiversity X X X
Safe community
environment X X

1805958.000 - 2920 23
NEBA relies upon comparative metrics for specific attributes of the environment to examine the
potential impacts and benefits from remediation and closure alternatives (Efroymson et al. 2003,
2004). NEBA methodology is not, however, prescriptive in defining attributes or comparative
metrics because each application of NEBA is unique to contaminant exposure, remediation and
closure alternatives, available data, and stakeholder concerns. NEBA is an extension of the risk
assessment process (Efroymson et al. 2004). As a result, receptors, exposure pathways, and risks
identified in a site risk assessment are key inputs to a NEBA. The links between key
environmental services, attributes that represent those services, and comparative metrics used in
this NEBA are summarized in Table 5-3.
Table 5-3. Matrix of key environmental services, attributes, and comparative metrics
applied in the NEBA
Attributes
Environmental Services Human Health
Risk
Ecological
Health Risk
Net Primary
Productivity
Transportation
Metrics
Safe ground water quality HI/ELCR -- --
Safe surface water quality HI/ELCR HQ
Safe soil and sediment quality HI/ELCR HQ --
Safe air quality HI/ELCR -- --
Safe food quality HI/ELCR HQ --
Protection of biodiversity HQ DSAYs
Recreation HI/ELCRa -- DSAYs
Natural beauty HQ DSAYs
Safe community environment -- Trucking
Logistics
Notes:
DSAYs – discounted service acre-years
ELCR – excess lifetime cancer risk
HI – hazard index
HQ – hazard quotient
a Estimated from health risks from consumption of fish.

I used human health attributes (e.g., risk to onsite construction workers, risk to offsite
swimmers) and risk quotients (hazard index [HI], excess lifetime cancer risk [ELCR]) to
evaluate whether there would be a potential impact to environmental services related to safe
water, air, and food under each ash basin closure option. I also used human health attributes to
evaluate whether there would be an impact to air quality during closure activities. I used

1805958.000 - 2920 24
ecological health attributes (e.g., risk to birds, mammals) and risk quotients (hazard quotient
[HQ]) to evaluate whether there would be a potential impact to environmental services related to
safe surface water and food and protection of biodiversity and natural beauty under the ash basin
closure options. I evaluated risk and disturbance associated with traffic and accidents using
transportation metrics and trucking logistics (e.g., number of truck miles driven) associated with
each closure option to evaluate impacts to community safety. I used net primary productivity
(NPP)37 and discounted service acre-years (DSAYs)38 to characterize differences in the
environmental services that derive from habitats (e.g., protection of biodiversity, natural beauty)
and that would be impacted by ash basin closure activities. Finally, I assembled all attributes,
services, and objectives within a full NEBA to examine which of the closure options best
maximizes environmental services to the local community. These metrics represent
scientifically appropriate and commonly applied metrics to evaluate risk to humans and the
environment (U.S. EPA 1989, 1997, 2000; NHTSA 2016) and to quantitatively measure
differences in environmental services associated with impact and restoration (Dunford et al.
2004; Desvousges et al. 2018; Penn undated; Efroymson et al. 2003, 2004).
Of note, my analysis did not consider the risks involved with onsite construction activities. For
example, I did not attempt to evaluate occupational accidents created by onsite construction and
excavation. Nor did I attempt to evaluate emissions associated with onsite construction
activities. Finally, I did not attempt to consider the risk created by disturbing the ash basin and
exposing it to the elements during excavation activities.
Some stakeholders also expressed concern over safety of the ash impoundment dam (NCDEQ
2016). The most recent dam safety report produced by Amec Foster Wheeler and submitted to
NCDEQ indicates “the construction, design, operation, and maintenance of the CCR surface

37 NPP represents the mass of chemically fixed carbon produced by a plant community during a given time
interval. It reflects the rate at which different ecosystems are able to sequester carbon, which is related to
mitigating climate change (https://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOD17A2_M_PSN).
38 DSAYs are derived from habitat equivalency analysis (HEA). HEA is an assessment method that calculates
debits based on services lost and credits for services gained from a remediation and closure action (Dunford et
al. 2004; Desvousges et al. 2018; Penn undated ). A discount rate is used to standardize the different time
intervals in which the debits and credits occur, so the services are usually expressed in terms of discounte d
service acre-years of equivalent habitat, or DSAYs, which provide a means to compare the different service
levels of affected habitat acres (Dunford et al. 2004; Desvousges et al. 2018; Penn undated).

1805958.000 - 2920 25
impoundments have been sufficiently consistent with recognized and generally accepted
engineering standards for protection of public safety and the environment” (Browning and
Thomas 2018).
5.3 NEBA Risk Ratings
NEBA organizes environmental hazard and benefit information into a unitless metric that
represents the degree and the duration of impact from a remediation and closure alternative
(Efroymson et al. 2003, 2004). One approach to structure this analysis is to create a risk-ranking
matrix that maps the proportional impact of a hazard (i.e., risk) with the duration of the impact
(Robberson 2006). The risk-ranking matrix used for this application of NEBA is provided in
Table 5-4. The matrix uses alphanumeric coding to indicate the severity of an impact: higher
numbers and higher letters (e.g., 4F) indicate a greater extent and a longer duration of impact,
respectively. Shading of cells within the matrix supports visualization of the magnitude of the
effect according to the extent and duration of an impact.39 When there is no meaningful risk, the
cell is not given an alphanumeric code. Risk ratings generated from the risk-ranking matrix for
each attribute and scenario examined were assembled into objective-specific summaries to
compare the net benefits of the closure options. All closure options in the NEBA were evaluated
against current conditions as a “baseline” for comparison.

39 Categories and shading as defined in the risk-ranking matrix are based on best professional judgment and used
for discussion of the relative differences in relative risk ratings. Alternative risk matrices and resulting NEBA
classifications are explored in Appendix E.

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Table 5-4. Risk-ranking matrix for impacts and risk from
remediation and closure activities.
Darker shading/higher codes indicate greater impact.

Duration of Impact (years)
10–15
(4)
5–9
(3)
1–4
(2)
<1
(1) % Impact No meaningful risk -- -- -- --
<5% (A) 4A 3A 2A 1A
5–19% (B) 4B 3B 2B 1B
20–39% (C) 4C 3C 2C 1C
40–59% (D) 4D 3D 2D 1D
60–79% (E) 4E 3E 2E 1E
>80% (F) 4F 3F 2F 1F
NEBA analysis of possible closure options for the ash basin at CSS helps both Duke Energy and
other stakeholders understand the net environmental benefits from the closure option
configurations that were examined. If a closure option that is preferred for reasons not
considered in the NEBA does not rate as one of the options that best maximizes environmental
services to the local community, closure plans for that option can be re-examined, and
opportunities to better maximize environmental benefits can be identified (e.g., including an
offsite habitat mitigation project to offset environmental services lost from habitat alteration).
The NEBA can then be re-run with the updated plan to compare the revised closure plan with
other closure options.
5.4 Risk Acceptability
Selecting any remediation, mitigation, restoration, or closure alternative involves considerations
of risk—risk posed by contamination in place, risk created by the action, risk remaining after the
action—and all of these risk considerations must be placed in some contextual framework if
informed decisions are to be made. Hunter and Fewtrell (2001) state, “The notion that there is
some level of risk that everyone will find acceptable is a difficult idea to reconcile and yet,
without such a baseline, how can it ever be possible to set guideline values and standards, given
that life can never be risk free?”

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EPA defines risk as “the chance of harmful effects to human health or to ecological systems
resulting from exposure to an environmental stressor” (U.S. EPA 2017a). In accordance with
EPA guidance for conducting ERAs (U.S. EPA 1997) and HHRAs (U.S. EPA 1989), risk to a
receptor (e.g., person, animal) exists when exposure to a stressor or stressors occur(s) at some
level of effect; however, because not all exposures produce adverse effects in humans or
ecological species, the exposure concentrations need to overlap with adverse effect thresholds
for there to be the potential for meaningful risk. The science supporting individual benchmarks
or levels of concern differs by the specific exposure at issue and the receptor at risk; however,
such benchmarks are considered by regulatory authorities to represent the best scientific
information available to create a baseline for risk (U.S. EPA 2017b).
The potential for risk associated with contamination is often evaluated using HQs, HIs, and
ELCRs to screen environmental media (e.g., water, soil) and identify the potential risk
associated with contamination (U.S. EPA 1989, 1997, 2000). The HQ is the ratio of an exposure
point concentration40 divided by an appropriate toxicity benchmark for the receptor, chemical,
and exposure scenario. An HI, which is used in HHRA, is the sum of the HQs for several
chemicals that share the same target organ. If the HQ or HI is less than 1, exposure to that
chemical (HQ) or group of chemicals (HI) is expected to result in no adverse effects to even the
most sensitive receptors. Cancer risk to humans is typically evaluated using a probabilistic
approach that considers an acceptable risk benchmark range of 10-4 to 10-6, meaning that a
person’s ELCR from the exposure being assessed is less than 1 in 10,000 to 1 in 1,000,000 (U.S.
EPA 1989, 2000).
NEBA relies on scientifically supported estimates of risk; however, regardless of the scientific
acceptability of the risk characterization process, stakeholders may place different values on
different types of risk.

40 A conservative estimate of the chemical concentration available from a particular media and exposure pathway.

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6 Summary of Conclusions
Based on my review and analyses, I developed the following conclusions which are structured
around the five objectives identified previously:
Conclusion 1: All closure options for the CSS ash basins are protective of human health.
Current conditions41 and conditions under all closure options support provision of safe drinking
water, safe surface water, safe food, and safe recreation, satisfying the first objective of ash
basin closure—to protect human health from CCR constituent exposure.
Conclusion 2: All closure options for the CSS ash basins are protective of ecological health.
Current conditions42 and conditions under all closure options support provision of safe surface
water, safe food consumption, and protection of biodiversity and natural beauty, satisfying the
second objective of ash basin closure—to protect ecological health from CCR constituent
exposure.
Conclusion 3: All closure options for the CSS ash basins create similar levels of
disturbance to communities All closure options support safe air quality from diesel truck
emissions along the transportation routes; however, each creates a comparable level of
disturbance and risk that could adversely impact community safety. Thus, all closure options
similarly satisfy the third objective of ash basin closure—to minimize risk and disturbance to
humans from closure.43

41 SynTerra’s updated HHRA considered only potential exposure pathways that currently exist and could remain
after ash basin closure under any closure option. Any potential risk currently associated with seeps at CSS was not
evaluated in the HHRA or considered in this analysis because any risk resulting from seeps will be eliminated,
reduced, or mitigated per the court-enforceable SOC that Duke entered with the North Carolina Environmental
Management Commission on April 18, 2018 (EMC SOC WQ S17-009; See Section 4.2).
42 SynTerra’s updated ERA considered only potential exposure pathways that currently exist and could remain after
ash basin closure under any closure option. Any potential risk currently associated with seeps at CSS was not
evaluated in the ERA or considered in this analysis because any risk resulting from seeps will be eliminated,
reduced, or mitigated per the court-enforceable SOC that Duke entered with the North Carolina Environmental
Management Commission on April 18, 2018 (EMC SOC WQ S17-009; See Section 4.2).
43 If for any reason (e.g., safety of personnel at CSS), the basins cannot be closed simultaneously, th e duration of
closure activities would be additive to an unknown degree for each basin, which has not been considered in my
analyses and may change risk ratings and NEBA conclusions.

1805958.000 - 2920 29
Conclusion 4: Most closure options for the CSS ash basins produce no net environmental
disturbance. All closure options, except for CIP closure of both the Unit 5 inactive ash basin
and the active ash basin (CIP/CIP), improve habitat-derived environmental services over
baseline conditions. Therefore, all closure options, except CIP closure of both basins (CIP/CIP),
have no net impacts to the protection of biodiversity and natural beauty, satisfying the fourth
objective of ash basin closure—to minimize risk and disturbance to the local environment from
closure.46
Conclusion 5: Most closure options for the CSS ash basins produce comparable
environmental services. All closure options, except for CIP closure of both the Unit 5 inactive
ash basin and the active ash basin (CIP/CIP), produce comparable environmental benefits with
equivalent protection of human and ecological health from CCR exposure, similar levels of
disturbance to humans, and net gains in habitat-derived environmental services,44 similarly
satisfying the fifth objective of ash basin closure—to maximize local environmental services.46
Each will be discussed in detail in the following sections.

44 As noted in Section 5 and further discussed in Section 11, the loss of habitat-derived environmental services
could be offset with an appropriate reforestation project.

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7 Conclusion 1: All closure options for the CSS ash
basins are protective of human health.
The first objective for ash basin closure, to protect human health from contaminant exposure, is
represented by environmental services that provide safe drinking water, safe groundwater, safe
surface water, safe food consumption, and safe recreation. For purposes of the NEBA, these
safety considerations were evaluated based on the following:
1. Provision of permanent alternative drinking water supplies to private well
water supply users within a 0.5-mile radius of CSS (Holman 2018);
2. Concentrations of CCR constituents of interest (COIs)45 in drinking water
wells that could potentially affect local residents and visitors, as
characterized by HDR (2015a) and SynTerra (2018a) in the
Comprehensive Site Assessment (CSA); and
3. Risk to various human populations from CCR exposure, as characterized
in the updated Human Health and Ecological Risk Assessment conducted
by SynTerra (2018b; Appendix B).
Through these two lines of evidence, I evaluated whether CCR constituents are currently
impacting drinking water wells, whether they will in the future, and whether other exposures to
CCR constituents pose a risk to human populations now or with ash basin closure.
7.1 Private water supply wells pose no meaningful r isk to the
community around CSS.
Per H.B. 630, Sess. L. 2016-95, all residents with drinking water supply wells within a 0.5-mile
radius of the CSS ash basin compliance boundary have been provided with permanent

45 COIs are constituents relevant to analysis of potential exposure to CCR constituents but are not necessarily
associated with risk to human or ecological receptors.

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alternative drinking water supplies (i.e., connection to public water supplier; Draovitch 2018),46
eliminating drinking water as a potential CCR exposure pathway for local residents or visitors.
Additionally, there are no public wells within a 0.5-mile radius of the CSS ash basin pre-2017
compliance boundaries, and available data indicate that private well water conditions are not
impacted by CCR constituents above background conditions and that groundwater flow paths
from the ash basin are away from residential wells (SynTerra 2018a).
As part of the 2018 CSA update, 71 private water supply wells were identified within a 0.5-mile
radius of the ash basin pre-2017 compliance boundaries. Most of the wells were located south,
southeast, east, and northeast of the active ash basin off McCraw Road, Prospect Church Road,
Fox Place, and Riverfront Drive; west and southwest of the Unit 5 inactive ash basin along
Duke Power Road, US-221A, and Old US- 221A; and north of the Broad River (SynTerra
2018a).
In 2016 and 2017, samples from private water supply wells were collected for chemical
analysis, and 2L47 or IMAC48 exceedances were detected for pH (14 wells), chromium (1 well),
cobalt (2 wells), iron (15 wells), manganese (4 wells), and vanadium (4 wells) (SynTerra
2018a). SynTerra (2018a) determined that provisional background threshold value
concentrations of manganese and vanadium were greater than 2L or IMAC standards, indicating
natural abundance of these elements in the regional groundwater. Results of the analysis of
water chemistry from private wells relative to the chemical composition of ash pore water,
background bedrock monitoring wells, and downgradient bedrock monitoring well data were
determined by SynTerra (2018a) to be consistent with the background bedrock well chemical
composition (SynTerra 2018a).

46 NCDEQ determined Duke Energy had satisfactorily completed the permanent alternative water provision under
CAMA General Statute (G.S.) 130A-309.21 l(cl) on October 12, 2108 (Holman 2018).
47 North Carolina Administrative code 15A NCAC 02L Groundwater Rules.
48 Interim maximum allowable concentration.

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7.2 CCR constituents from the CSS ash basins pose no
meaningful risk to human populations.
To assess potential risk to humans both onsite and offsite using the most recent and
comprehensive data available, SynTerra updated the baseline HHRA (SynTerra 2018b)
originally conducted by HDR (2016c) as a component of the CAP part 2 (HDR 2016a). The
updated HHRA included updates49 to the conceptual site model, exposure point concentrations
for human receptors with complete exposure pathways, screening level risk assessments for
human receptors with complete exposure pathways, and hazard calculations (HI, ELCR) for
receptors and COPCs with plausible complete exposure pathways.
Consistent with the 2016 baseline human health and ecological risk assessment (HDR 2016c),
the updated HHRA (SynTerra 2018) examined CCR constituent exposure to a range of human
populations, including construction workers, swimmers, waders, boaters, and recreational and
subsistence fishers under different pathways (i.e., exposure to sediment, surface water,
groundwater, or fish tissue). HIs and ELCRs were estimated for scenarios with plausible
complete exposure pathways.
Complete CCR exposure pathways evaluated in the updated HHRA included the following
(SynTerra 2018):
 Onsite construction workers via groundwater50
 Offsite recreational swimmers via offsite surface water and sediment
 Offsite recreational waders via offsite surface water and sediment
 Offsite recreational boaters via offsite surface water
 Offsite recreational fishers via offsite surface water and fish tissue
 Offsite subsistence fishers via fish tissue.

49 Updates to risk assessments are a natural part of the risk analysis process. EPA guidance for ecological risk
assessment notes, “The [risk assessment] process is more often iterative than linear, since the evaluation of new
data or information may require revisiting a part of the process or conducting a new assessment as more
information about a site is gained through site investigations, the risk assessment must be updated to reflect the
best knowledge of potential risk at a site” (U.S. EPA 1998). EPA similarly describes human health risk
characterization as an iterative process (U.S. EPA 2000).
50 Groundwater exposure to onsite construction workers was evaluated in the updated HHRA, though a pathway
for exposure was considered incomplete by SynTerra (2018).

1805958.000 - 2920 33
Since all households with drinking water supply wells within a 0.5-mile radius of the CSS
compliance boundary have received permanent alternative water supplies (Holman 2018) and no
potable water wells are located downgradient of CSS (SynTerra 2018a), offsite drinking water
risks were not further evaluated for groundwater because there was no complete exposure
pathway. A summary of the risk assessment results from the updated HHRA (SynTerra 2018b)
is provided in Table 7-1.
Table 7-1. Summary of human health risk assessment hazard index (HI) and excess
lifetime cancer risk (ELCR) from SynTerra (2018b)
Media Receptor HI ELCR
Groundwater Construction Worker 0.003 NC
Sediment Recreational Swimmer 0.008 1.3×10-7
Surface Water Recreational Swimmer 0.007 1.3×10-6
Sediment Recreational Wader 0.008 1.3×10-7
Surface Water Recreational Wader 0.004 3.1×10-7
Surface Water Recreational Boater 0.0008 2.6×10-8
Surface Water Recreational Fisher 0.0008 2.6×10-8
Biota (fish) Recreational Fisher 0.2 1.9×10-6
Biota (fish) Subsistence Fisher 5 1.44×10-4
Notes:
NC - Risk based concentration based on non-cancer HI.
The majority of exposure scenarios assessed by SynTerra (2018b) indicated that exposure to
CCR poses no meaningful risks to humans. The HI and ELCR associated with subsistence
fishers were estimated to be greater than 1 and 1×10-4, respectively, and I examined the
foundation for these more specifically.
Risk assessment is subject to a number of uncertainties, including the representativeness of
sample data, the degree to which exposure assumptions approximate actual exposure, estimation
of chemical toxicity, and characterization of background concentrations. Risk assessment
typically addresses these uncertainties by including conservative assumptions that tend to
overestimate exposure and risk. For example, to evaluate potential risk to subsistence fishers in
the CSS HHRA, SynTerra (2018) used a fish consumption rate of 170 g/day, which represents
the highest level of consumption (95th percentile) in a high consuming subsistence Native

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American population living in an area with plentiful fish resources that can support such high
fish consumption (Columbia River Tribes in Oregon) (U.S. EPA 2000a, 2011a).51 SynTerra
(2018b) further assumes this rate of fish consumption would continue for many years using only
fish from a single water body with fish tissue COPC concentrations estimated using a
conservative uptake model (bioconcentration factors [BCFs]) from the highest surface water
COPC concentrations. Each exposure pathway in the HHRA uses similarly conservative
assumptions to address uncertainty. While this serves to ensure a health protective assessment,
results that exceed target risk levels should be examined in more depth to understand the
context. Therefore, I examined the foundation for each exceedance in more detail.
Risk to fishers was modeled by SynTerra (2018b) by estimating fish tissue concentrations from
surface water sample data. The cumulative HI of 5 for subsistence fishers from these exposures
was driven by concentrations of cobalt. A similar risk of cobalt to subsistence fishers was noted
previously in the baseline HHRA (HDR 2016c), and HDR (2016c) attributed this estimated risk
to the use of onsite surface water as a surrogate for offsite conditions as well as conservative
uptake assumptions and bioaccumulation models used for cobalt exposure, which likely
overestimate cobalt concentrations in fish tissue. The cumulative ELCR of 1.44×10-4 for
subsistence fishers was driven by concentrations of chromium (VI). This risk was not identified
in the previous HHRA (HDR 2016c), as more recent samples were included in the 2018 analysis
(SynTerra 2018b).
Examining these two COPCs individually, for cobalt, the EPA provisional oral reference dose
(RfD) of 0.3 µg/kg/day may be considered unnecessarily conservative.52 A recent reanalysis of
relevant human and animal studies involving oral exposure to cobalt proposed a new RfD for
cobalt of 30 µg/kg/day, which is 100 times higher than what is currently recommended by the
EPA (Finley et al. 2012; Schoof 2017). Other government agencies have derived higher
guidance values for cobalt, including the Dutch National Institute of Public Health and the
Environment (tolerable daily intake of 98 µg/day, or 1.4 µg/kg/day for a 70 kg adult) and the
European Food Safety Authority (EFSA) (600 µg/day, or 8.6 µg/kg/day) (Schoof 2017). If the

51 In the case of CSS, SynTerra (2018b) has not identified any populations of subsistence fishers in the area.
52 The RfD is an estimate of a daily exposure to the human population that is likely to be without an appreciable
risk of deleterious effects during a lifetime. The cobalt RfD was developed in 2008 (U.S. EPA 20 08).

1805958.000 - 2920 35
recent cobalt RfD reported in Finley et al. (2012) were applied instead of the older EPA RfD for
cobalt, the HI for cobalt exposure to fishers in the Broad River would be 0.05, indicating no
meaningful risk to subsistence fishers from cobalt. SynTerra (2018b) notes that concentrations
of cobalt in background samples collected near CSS were of the same order of magnitude as the
EPC used in the risk calculations and would, thus, predict a comparable level of background risk
unassociated with CCR exposure. Based on this more detailed review, I conclude there is no
meaningful risk to subsistence fishers from exposure to cobalt in the Broad River.
For chromium (VI), the ELCR of 1.44×10-4 is less than an order of magnitude above the upper
end of the EPA’s target ELCR range of 10-6 to 10-4 (U.S. EPA 1989, 2000). This ELCR was
determined using a bioconcentration factor (BCF) for chromium (VI) of 200, based on a 1996
report from the National Council on Radiation Protection and Management (NCRP 1996).
However, a more recent review by California EPA evaluated chromium uptake in fish and
derived a lower BCF for chromium based primarily on studies of chromium (VI). OEHHA
(2012) states that chromium (VI) is not well taken up into edible fish tissue and recommends a
BCF of 20 (OEHHA 2012). Had a BCF of 20 been used the resulting ELCR would be 1.44×10-
5, within EPA’s range of acceptable risk. SynTerra (2018) notes that concentrations of
chromium (VI) in background samples were of the same order of magnitude as the EPC used in
risk calculations, and would predict a comparable level of background risk unassociated with
CCR exposure. Based on the conservative uptake assumptions and bioaccumulation factors used
in this model, and the very limited exceedance of acceptable ELCR, I conclude there is no
meaningful risk to subsistence fishers from exposure to chromium (VI) in the Broad River.
Given the lack of meaningful risk under current conditions,53 there is also no meaningful risk to
humans from CCR exposure under any of the ash basin closure options since all options reduce
or eliminate exposure pathways following closure. Thus, all closure options are protective of
public health.

53 SynTerra’s updated HHRA considered only potential exposure pathways that currently exist and could remain
after ash basin closure under any closure option. Any potential risk currently associated with seeps at CSS was not
evaluated in the HHRA or considered in this analysis because any risk resulting from seeps will be eliminated,
reduced, or mitigated per the court-enforceable SOC that Duke entered with the North Carolina Environmental
Management Commission on April 18, 2018 (EMC SOC WQ S17-009; See Section 4.2).

1805958.000 - 2920 36
7.3 NEBA – Protection of Human Health from CCR Exposure
Based on these analyses, there is no CCR risk from drinking water supplies, no evidence of
CCR impacts to drinking water wells, and no meaningful risk to humans from CCR exposure
under current conditions or under any closure option. Using the NEBA framework and relative
risk ratings, these results are summarized in Table 7-2 within the objective of protecting human
health from exposure to CCR constituents.
Table 7-2. Summary of relative risk ratings for attributes that characterize potential
hazards to humans from CCR exposure in drinking water, surface water,
groundwater, soil, sediment, food, and through recreation
Objective Protect Human Health from CCR
Hazard Exposure to CCR Potentially Affected Populations Local Residents/Visitors Onsite Construction Workers Offsite Recreational Swimmers Offsite Recreational Waders Offsite Recreational Boaters Offsite Recreational Fishers Offsite Subsistence Fishers Scenario (Unit 5/Active ash basin closure option)
Baseline -- -- -- -- -- -- --
CIP/CIP -- -- -- -- -- -- --
CIP/Excavation -- -- -- -- -- -- --
CIP/Hybrid -- -- -- -- -- -- --
Excavation/CIP -- -- -- -- -- -- --
Excavation/Excavation -- -- -- -- -- -- --
Excavation/Hybrid -- -- -- -- -- -- --
“--” indicates “no meaningful risk.”
Current conditions and conditions under all closure options support provision of safe drinking
water, safe surface water, safe food, and safe recreation, satisfying the first objective of ash
basin closure—to protect human health from CCR constituent exposure.

1805958.000 - 2920 37
8 Conclusion 2: All closure options for the CSS ash
basins are protective of ecological health.
The second objective for ash basin closure, to protect ecological health from CCR exposure, is
represented by environmental services that provide safe surface water, safe food consumption,
and protection of biodiversity and natural beauty. For purposes of the NEBA, these
considerations were evaluated based on the following:
1. Risk to ecological receptors from CCR exposure, as characterized by
SynTerra (2018b; Appendix B) in the updated human health and ecological
risk assessment; and
2. Aquatic community health in the Broad River as reported in the 2010
environmental monitoring report (Coughlan et al. 2010).
Through these two lines of evidence, I evaluated whether CCR constituents pose a risk to
ecological populations now or after ash basin closure.
8.1 No meaningful risks to ecological receptors from CCR
exposure exist under current conditions or any closure
option.
To assess potential risk to ecological receptors both onsite and offsite using the most recent and
comprehensive data available, SynTerra (2018b) updated the baseline human health and
ecological risk assessment that was originally conducted by HDR (2016c) as a component of the
CAP part 2 (HDR 2016a). The updated ERA included updates to the conceptual site model,
exposure point concentrations for receptors with potentially complete exposure pathways, and
screening level risk assessments for ecological receptors with potentially complete exposure
pathways. Updated HQs were estimated for receptors and COPCs with plausible potentially
complete exposure pathways (SynTerra 2018b).
The ecological receptors evaluated in the ERA are common representatives of particular groups
of organisms inhabiting different habitats and aspects of the food web. Key receptors in

1805958.000 - 2920 38
SynTerra’s updated ERA (SynTerra 2018b) and their potential pathways for exposure included
the following:
 Birds: Avifauna species may be exposed by ingestion of food and surface
water and by incidental ingestion of sediment and soil. Aquatic/wetland
species included were mallard duck (omnivore) and great blue heron
(piscivore).
 Mammals: Aquatic/wetland or terrestrial species may be exposed by
ingestion of food and surface water and by incidental ingestion of sediment
and soil. Aquatic/wetland species included were muskrat (omnivore) and
river otter (piscivore).
Ecological risk for these indicator species was characterized by SynTerra (2018b) using a risk-
based screening approach that compared chemical exposure levels to chemical toxicity
references values (TRVs) to calculate HQs for COPCs. TRVs in the ERA included no-observed-
adverse-effects levels (NOAELs)54 and lowest-observed-adverse-effects levels (LOAELs)55
derived from the literature for each COPC.
HQ results for the site were evaluated for three areas of CSS56 (Figure 8-1). HQs less than 1
indicate no meaningful risk to ecological receptor species associated with exposure to the
COPCs evaluated.
 Exposure Area 1: NOAEL HQ >1 for muskrat exposure to aluminum;
however, LOAEL HQ <1 for muskrat exposure to aluminum, indicating no
meaningful risk. All other HQs<1, also indicating no meaningful risk to the
other ecological receptors.

54 A NOAEL is a concentration below which no adverse effects have been observed for a specific receptor and
pathway of exposure. NOAELs are typically estimated from laboratory toxicity tests.
55 A LOAEL is a concentration associated with the lowest concentration level at which adverse effects have been
observed for a specific receptor and pathway of exposure. LOAELs are typically estimated from laboratory
toxicity tests.
56 The baseline ecological risk assessment conducted by HDR in 2016 (HDR 2016c) included four exposure areas.
Exposure Area 3 (located southwest of the active ash basin east of Suck Creek) is considered a background
location by SynTerra and was not evaluated in SynTerra’s updated ERA (SynTerra 2018b).

1805958.000 - 2920 39
 Exposure Area 2: All HQs <1, indicating no meaningful risk to ecological
receptors in this area.
 Exposure Area 4: All HQs <1, indicating no meaningful risk to ecological
receptors in this area.
Based on the updated ecological risk assessment (SynTerra 2018b), there are currently no
meaningful risks to ecological receptors associated with CCR exposure at CSS.
Additionally, the 2010 environmental monitoring report (Coughlan et al. 2010) for the Broad
River reported results from biological sampling (macroinvertebrates and fish) and water
chemistry analyses conducted between 2002 and 2007. The report concluded, “Based on the
diversity and sustainability of the fish community through time, the scarcity of pollution-tolerant
individuals, and the trophic structure of the fish community, it is concluded that a balanced and
indigenous fish community exists in the Broad River in the vicinity of CSS” (Coughlan et al.
2010). Similarly, the benthic macroinvertebrate community in the Broad River upstream and
downstream of CSS was also found to be a generally balanced and indigenous community
(Coughlan et al. 2010).
Given the lack of meaningful ecological risk from CCR exposure under current conditions based
on the lines of evidence evaluated, all closure options would be protective of ecological
receptors since all closure options reduce or eliminate potential exposure pathways.

1805958.000 - 2920
40

Figure 8-1. Exposure areas evaluated in the 2018 Ecological Risk Assessment update.
Reproduced from SynTerra (2018b).

1805958.000 - 2920 41
8.2 NEB A – Protection of Environmental Health from CCR
Exposure
Based on these analyses, no meaningful risk to ecological receptors from CCR exposure was
found under current conditions57 or under any closure option. Using the NEBA framework and
relative risk ratings, within the objective of protecting environmental health from exposure to
CCR constituents, these results are summarized in Table 8-1.
Table 8-1. Summary of relative risk ratings for attributes that characterize potential
hazards to ecological resources from CCR exposure in surface water, soil,
sediment, and food
Objective Protect Ecological Health from CCR
Hazard Exposure to CCR Affected Populations Fish Populations Aquatic Omnivore Birds (mallard) Aquatic Piscivore Birds (great blue heron) Aquatic Herbivore Mammals (muskrat) Aquatic Piscivore Mammals (river otter) Scenario (Unit 5/Active ash basin closure option
Baseline -- -- -- -- --
CIP/CIP -- -- -- -- --
CIP/Excavation -- -- -- -- --
CIP/Hybrid -- -- -- -- --
Excavation/CIP -- -- -- -- --
Excavation/Excavation -- -- -- -- --
Excavation/Hybrid -- -- -- -- --
“--” indicates “no meaningful risk.”

57 SynTerra’s updated ERA considered only potential exposure pathways that currently exist and could remain after
ash basin closure under any closure option. Any potential risk currently associated with seeps at CSS was not
evaluated in the ERA or considered in this analysis because any risk resulting from seeps will be eliminated,
reduced, or mitigated per the court-enforceable SOC that Duke entered with the North Carolina Environmental
Management Commission on April 18, 2018 (EMC SOC WQ S17-009; See Section 4.2).

1805958.000 - 2920 42
Current conditions and conditions under all closure options support provision of safe surface
water, safe food consumption, and protection of biodiversity and natural beauty, satisfying the
second objective of ash basin closure—to protect ecological health from CCR constituent
exposure.

1805958.000 - 2920 43
9 Conclusion 3: All closure options for the CSS ash
basins create similar levels of disturbance to
communities.
The third objective for ash basin closure, to minimize human disturbance and risk from closure,
is represented by environmental services that provide safe air quality and a safe community
environment. For purposes of the NEBA, these considerations were evaluated based on the
following:
1. Health risks from diesel exhaust emissions to the community living and
working along transportation corridors during trucking operations to haul
materials to and from the ash basin, as evaluated through the application of
diesel truck air emissions modeling and HHRA; and
2. The relative risk for disturbance and accidents resulting from trucking
operations affecting residents living and working along transportation
corridors during construction operations, as evaluated by comparing the
relative differences in trucking operations between the potential closure
options.
All closure options require increased trucking activity to haul materials to the site (e.g., transport
cap material from a borrow site to the ash basin) or to haul materials away from the site (e.g.,
transport coal ash from the ash basin to a lined landfill). These activities involve the use of
diesel-powered dump trucks, which increase local diesel exhaust emissions and traffic, both of
which present potential hazards to local populations in the form of air pollution and roadway
hazards. Table 9-1 summarize the transportation logistics associated with each of the closure
options Duke Energy is considering for CSS (Duke Energy 2018). The amount of offsite

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trucking involved in all closure options is relatively similar, but the duration of construction
under the closure options varies more substantially.58

58 It is important to note that estimates of the duration of closure and construction assume that both the Unit 5
inactive ash basin and the active ash basin can be closed simultaneously, an assumption that has not received a
feasibility analysis. If for any reason (e.g., safety of personnel at CSS), the basins cannot be closed
simultaneously, the duration of closure activities would be additive to an unknown degree for each basin, which
has not been considered in my analyses and may change risk ratings and NEBA conclusions.

1805958.000 - 2920
45
Table 9-1. Summary of offsite transportation logistics associated with each closure option (Duke Energy 2018)
Logistics CIP/CIP
CIP/
Excavation CIP/Hybrid
Excavation/
CIP
Excavation/
Excavation
Excavation/
Hybrid
Closure Duration (years)a 6 9 8 6 9 8
Construction Duration (years)a,b 3 6 5 3 6 5
Offsite truck loads to haul cap & fill materialc 6,615 8,167 6,596 7,381 8,933 7,362
Offsite miles driven to haul cap & fill materialc 192,015 195,615 181,962 208,701 212,301 198,648
a Includes design and permitting, decanting, site preparation, construction, and site restoration. Assumes closure of the basins can occur simultaneously. A construction
feasibility analysis of this assumption has not been conducted. If the basins were to be closed sequentially, the duration of the estimated closure for each option would be
substantially longer.
b Includes site preparation, construction, and site restoration. Assumes closure of the basins can occur simultaneously.
c Includes cover soil, top soil, and geosynthetic material.
d Includes ash, over-excavated soil, and removed dams and embankments.

1805958.000 - 2920 46
Costs to society associated with trucking include accidents (fatalities, injuries, and property
damage), emissions (air pollution and greenhouse gases), noise, and the provision, operation,
and maintenance of public roads and bridges (Forkenbrock 1999). Generally, the magnitude of
these impacts scales with the frequency, duration, and intensity of trucking operations
(Forkenbrock 1999). Figure 9-1 illustrates the normalized differences between offsite
transportation activities under excavation and hybrid closure options compared to CIP. These
results reinforce the similarity in trucking operations between the closure options (i.e., the
multipliers for total offsite volume moved, total offsite loads, and total offsite miles are
approximately 1) but also the larger relative differences in the duration of construction
operations between the options.

Figure 9-1. Normalized differences between all offsite transportation activities
under combinations of CIP, excavation, and hybrid options.
Bars represent the increased activity under closure options
compared to CIP for both basins.
9.1 There is no meaningful risk from diesel emissions to
people living and working along the transportation
corridor.
The types of large dump trucks that will be used in closure activities at CSS are generally diesel
powered, and diesel exhaust includes a variety of different particulates and gases, including

1805958.000 - 2920 47
more than 40 toxic air contaminants.59 North Carolina does not have a diesel-specific health-
based toxicity threshold because diesel exhaust is not currently regulated as a toxic air pollutant.
North Carolina also does not regulate PM2.5 or PM1060 as toxic air pollutants. North Carolina
defers to EPA’s chronic non-cancer reference concentration (RfC) for diesel particulate matter
(DPM) of 5 µg/m3 based on diesel engine exhaust to estimate risk from diesel emissions.61
California is, to my knowledge, the only state that currently regulates diesel as a toxic air
contaminant and has identified both an inhalation non-cancer chronic reference exposure level
(REL)62 of 5 µg/m3 and a range of inhalation potency factors indicating that a “reasonable
estimate” for the inhalation unit risk is 3.0×10-4 (µg/m3)-1 “until more definitive mechanisms of
toxicity become available” (OEHHA 2015). California bases the non-cancer and cancer health
factors on the whole (gas and particulate matter) diesel exhaust and uses PM10 as a surrogate
measure.
As PM10 is the basis for both the non-cancer and inhalation risk factors for diesel exhaust
exposure in California, I relied on a PM10 exposure model to evaluate potential non-cancer and
cancer health risks from diesel exhaust.63
A representative segment of road was simulated using EPA’s AERMOD model64 to quantify air
concentrations at set distances away from the road (U.S. EPA 2016). Diesel truck emissions
were configured in the model in a manner consistent with the recommendations from EPA’s
Haul Road Working Group (U.S. EPA 2011). The emission rate for diesel trucks was calculated

59 https://oehha.ca.gov/air/health-effects-diesel-exhaust
60 PM2.5 and PM10 are airborne particulate matter sizes. PM2.5 is particulate matter that is 2.5 µm or less in size;
PM10 is particulate matter that is 10 µm or less in size.
61 Integrated Risk Information System (IRIS). U.S. EPA. Diesel engine exhaust.
62 A chronic REL is a concentration level (expressed in units of micrograms per cubic meter [µg/m3]) for
inhalation exposure at or below which no adverse health effects are anticipated following long-term exposure.
EPA has defined long-term exposure for these purposes as at least 12% of a lifetime, or about eight years for
humans.
63 California regulations and guidance indicate that when comparing whole diesel exhaust to speciated
components of diesel (e.g., polycyclic aromatic hydrocarbons, metals) the cancer risk from inhalation of whole
diesel exhaust will outweigh the multi-pathway analysis for speciated components.
64 AERMOD will calculate both the downwind transport and the dispersion of pollutants emitted from a source.
Both transport and dispersion are calculated based on the observed meteorology and characteristics of the
surrounding land. AERMOD is maintained by EPA and is the regulatory guideline model for short-range
applications (transport within 50 km).

1805958.000 - 2920 48
using the U.S. EPA Mobile Vehicle Emissions Simulator (MOVES) model (U.S. EPA 2015).65
Emission factors were then applied to the average number of anticipated offsite truck trips each
year to define the average annual amount of DPM emitted along the representative road
segment, and these exposures were then summed over seventy years.66 AERMOD simulations
were run for four transportation orientation directions and used five years of local
meteorological data to estimate exposure point concentrations at regular intervals from 10 to
150 m perpendicular to either side of the road. The results of the model were translated into
average PM10 exposure (µg/m3) and excess cancer risk over a 70-year period using reasonable
maximum exposure.67 Results of the exposure modeling are provided in Table 9-2. Full results
and a more detailed description of the model are provided in Appendix C.

65 The MOVES model allows a user to determine fleet average emission factors (in units of grams of pollutant per
mile traveled) for specific classes of vehicles and specific years. In this application, factors defined by MOVES
for single unit short-haul diesel truck were used.
66 For the cancer risk analysis, emissions were calculated as an average over the regulatory default 70-year
residential exposure duration. If the truck activity for a closure option occurs over a shorter period, the duration
of the truck activity exposure is factored into the 70 -year averaging time (OEHHA 2015).
67 Long-term exposure was incorporated into the air simulation as the average exposure given estimated trucking
rates for 12 hours per day—7am to 7 pm—6 days a week for the duration of the project trucking time.

1805958.000 - 2920
49
Table 9-2. Hazard indices (HI) and excess lifetime cancer risk (ELCR) from exposure
to diesel exhaust emissions along transportation corridors near CSS.
Results are for the maximum exposures modeled.
Perpendicular
Distance
from the
Road
CIP/CIP CIP/Excavation CIP/Hybrid Excavation/CIP Excavation/Excavation Excavation/Hybrid
Cancer
Non
Cancer

Cancer
Non
Cancer

Cancer
Non
Cancer

Cancer
Non
Cancer

Cancer
Non
Cancer

Cancer
Non
Cancer
ELCR HI ELCR HI ELCR HI ELCR HI ELCR HI ELCR HI
10 m 2.15E-09 0.0000

2.17E-09 0.0000

2.00E-09 0.0000

2.40E-09 0.0000

2.38E-09 0.0000

2.23E-09 0.0000
20 m 1.83E-09 0.0000

1.85E-09 0.0000

1.70E-09 0.0000

2.05E-09 0.0000

2.03E-09 0.0000

1.90E-09 0.0000
30 m 1.45E-09 0.0000

1.47E-09 0.0000

1.35E-09 0.0000

1.62E-09 0.0000

1.61E-09 0.0000

1.51E-09 0.0000
40 m 1.19E-09 0.0000

1.21E-09 0.0000

1.11E-09 0.0000

1.33E-09 0.0000

1.32E-09 0.0000

1.24E-09 0.0000
50 m 1.01E-09 0.0000

1.02E-09 0.0000

9.38E-10 0.0000

1.13E-09 0.0000

1.12E-09 0.0000

1.05E-09 0.0000
60 m 8.75E-10 0.0000

8.85E-10 0.0000

8.13E-10 0.0000

9.76E-10 0.0000

9.68E-10 0.0000

9.07E-10 0.0000
70 m 7.81E-10 0.0000

7.90E-10 0.0000

7.26E-10 0.0000

8.72E-10 0.0000

8.64E-10 0.0000

8.10E-10 0.0000
80 m 7.05E-10 0.0000

7.13E-10 0.0000

6.56E-10 0.0000

7.87E-10 0.0000

7.80E-10 0.0000

7.32E-10 0.0000
90 m 6.43E-10 0.0000

6.50E-10 0.0000

5.98E-10 0.0000

7.18E-10 0.0000

7.11E-10 0.0000

6.67E-10 0.0000
100 m 5.92E-10 0.0000

5.98E-10 0.0000

5.50E-10 0.0000

6.60E-10 0.0000

6.55E-10 0.0000

6.14E-10 0.0000
110 m 5.47E-10 0.0000

5.53E-10 0.0000

5.09E-10 0.0000

6.11E-10 0.0000

6.05E-10 0.0000

5.68E-10 0.0000
120 m 5.09E-10 0.0000

5.15E-10 0.0000

4.73E-10 0.0000

5.68E-10 0.0000

5.63E-10 0.0000

5.28E-10 0.0000
130 m 4.76E-10 0.0000

4.81E-10 0.0000

4.42E-10 0.0000

5.31E-10 0.0000

5.27E-10 0.0000

4.94E-10 0.0000
140 m 4.47E-10 0.0000

4.52E-10 0.0000

4.15E-10 0.0000

4.98E-10 0.0000

4.94E-10 0.0000

4.63E-10 0.0000
150 m 4.20E-10 0.0000 4.25E-10 0.0000 3.91E-10 0.0000 4.69E-10 0.0000 4.65E-10 0.0000 4.36E-10 0.0000

1805958.000 - 2920 50
Based on the assumptions applied in the air model, no meaningful risk from diesel emissions
associated with ash basin closure trucking operations was identified for people living and
working along the transportation corridor. The exposure model and risk assessment applied here
represent a simple approach to estimate risk. A more refined estimate of risk could be computed
with a more sophisticated air and risk model; however, it is unlikely to change the conclusion
that there is no meaningful risk to people living and working along the transportation corridor
from diesel emissions associated with ash basin closure construction operations.
9.2 The likelihood of noise, traffic, and accidents from
transportation activities is similar under all closure
options.
Increased trucking increases noise and traffic congestion and creates a statistically based risk for
increased traffic accidents that could result in fatalities, injuries, and/or property damage
(Forkenbrock 1999; NHTSA 2016). CSS is located on North Carolina state road (SR) 1002
(Duke Power Rd/McCraw Rd) immediately adjacent to US Route 221-A, which I assumed
would be the primary transportation route for construction material hauling (see Figure 4-1).
There will be an increase in trucking traffic hauling topsoil and/or geosynthetic material under
all closure options along this corridor, with a statistically increased likelihood of traffic
accidents (NHTSA 2016). These accidents and associated risks to life, health, and property will
generally scale with the frequency and duration of trucking, total number of truckloads, number
of roundtrip truck trips per day, and duration of the closure.
For purposes of the NEBA two attributes of offsite truck traffic that create disturbance to local
communities were considered: (1) noise and congestion and (2) accidents. Noise and congestion
were evaluated by comparing the number of times a construction truck would be expected to
pass a given location along the transportation corridor during closure construction activities,
assuming all trucks must pass this location. The difference in the likelihood of traffic accidents
between the closure options was assumed to be a function of the number of offsite road miles
driven by construction trucks (NHTSA 2016).

1805958.000 - 2920 51
9.2.1 Noise and Congestion
Regardless of the option, closure of the ash basins at CSS will result in an increased number of
large trucks68 on local roads (Table 9-1). Noise from these trucks includes engine and braking
noise, which can be disruptive to the communities through which they are passing,69 and trucks
frequently passing through rural communities may pose additional disturbance from roadway
congestion. To compare the disturbance of trucking noise and congestion between closure
options, I used the average daily number of truck passes for trucks carrying earthen fill and
geosynthetic material to the construction site (Table 9-1). Excavation of the Unit 5 inactive
basin and CIP closure of the active ash basin (Excavation/CIP) is estimated to result in the
largest average number of truck passes per day at 15, hauling nearly 146,000 CY of material in
over 7,300 loads for over 3 years (38 months). CIP closure of the Unit 5 inactive basin and
excavation closure of the active ash basin result in the lowest number of average truck passes
per day (8), though this closure option hauls more volume, approximately 163,000 CY in 8,200
loads, and the disturbance occurs over more than 6 years (75 months). Results for all closure
options and their relative differences (as the ratio to CIP/CIP closure) are summarized in Table
9-3.
9.2.2 Traffic Accidents
Traffic accidents are assumed to be a function of the total number of offsite road miles driven by
construction trucks (NHTSA 2016). The CIP/hybrid closure option requires the fewest total
miles of offsite driving, approximately 182,000 miles, while the excavation/excavation closure
option requires the most offsite miles driven, approximately 212,000 miles. The difference in
distance driven between the CIP/hybrid and excavation/excavation closure options (30,339
miles) is more than one trip around the earth. Table 9-3 summarizes the results for all
disturbances considered.

68 Twenty-ton dump trucks, or similar vehicles for bulk transport, are assumed to be the primary vehicles that will
be involved in transporting materials during closure construction activities.
69 A typical construction dump truck noise level is approximately 88 decibels 50 ft. from the truck.
(https://www.fhwa.dot.gov/ENVIRONMENT/noise/construction_noise/handbook/handbook09.cfm)

1805958.000 - 2920 52
Table 9-3. Comparative metrics for increased noise and congestion and traffic
accidents
Months
of
truckinga
Noise and congestion Traffic Accidents
Average truck
passes per day
Ratio to
CIP
Total offsite
road miles driven
Ratio to
CIP
CIP/CIP 38 13 1 192,015 1
CIP/
Excavation
75 8 0.63 195,615 1.50
CIP/Hybrid 57 9 0.66 181,962 1.31
Excavation/
CIP
38 15 1.12 208,701 1.51
Excavation/
Excavation
75 9 0.68 212,301 1.92
Excavation/
Hybrid
57 10 0.74 198,648 1.73
a Duration estimates assume simultaneous closure of the Unit 5 and active ash basins. A construction feasibility analysis of
this assumption has not been conducted. If the basins were to be closed sequentially, the duration of the estimated closure
for each option would be substantially longer.

9.3 NEB A – Minimize Human Disturbance
From these analyses, no meaningful health risk is expected from diesel exhaust emissions under
any closure option, but the closure options are expected to produce community disturbance in
the form of noise, traffic congestion, and risk of traffic accidents.
I used the number of trucks per day passing70 a receptor along a near-site transportation corridor
to examine the differences in noise and traffic congestion under the closure options. I compared
the increase in the average number of trucks hauling earthen fill, geosynthetic material, and
other materials under the closure options to the current number of truck passes for the same
receptor. I specified a baseline, or current, level of truck passes on the transportation corridor,
and the number of truck passes per day under the closure options were derived directly from the
trucking projections and implementation schedules provided by Duke Energy.

70 Truck passes per day is calculated as the total number of loads required to transport earthen fill, geosynthetic
material, and other materials multiplied by two to account for return trips. The resulting total number of passes
is then divided evenly among the total number of months of trucking time multiplied by 26 working days per
month.

1805958.000 - 2920 53
A baseline estimate of trucking passes per day for transportation corridors near CSS was derived
from North Carolina Department of Transportation (NCDOT) data of annual average daily
traffic (AADT) at thousands of locations across the state and the proportion of road miles driven
by large trucks in the Cleveland and Rutherford counties.71 Based on the assumed 97 truck-per-
day baseline level and the number of truck trips per day from Duke Energy’s closure
projections, all options would have a an impact of 15% or less (CIP/CIP = 14%,CIP/Excavation
= 9%, CIP/Hybrid = 9%, Excavation/CIP = 15%, Excavation/Excavation = 9%,
Excavation/Hybrid = 10%) on noise and congestion. I input these percent impacts to the risk-
ranking matrix (Table 5-4) along with the total duration of trucking activities (Table 9-1) to
evaluate which of the closure options best minimizes human disturbances (
Table 9-4).
I evaluated risk of traffic accidents by comparing the average number of annual offsite road
miles driven between closure options relative to a baseline estimate of the current road miles
driven.72 I chose a baseline of 60 million annual road miles for Rutherford and Cleveland
Counties, North Carolina, based on the reported average total vehicle miles traveled in these
counties (NCDMV 2017) multiplied by the counties’ average 6.9% contribution of trucks to
total AADT (NCDOT 2015). I used the increase in truck miles driven over baseline in the
closure options as a surrogate for the potential increase in traffic accidents.
Using the 60.4-million-truck-miles baseline assumption, all closures have a relative risk rating
of <5% (CIP/CIP = 0.1%, CIP/Excavation = 0.05%, CIP/Hybrid = 0.06%, Excavation/CIP =
0.11%, Excavation/Excavation = 0.06%, Excavation/Hybrid = 0.07%). These relative risk
ratings appear to be insensitive to lower assumed baseline annual truck miles (see Appendix E
for sensitivity analysis); reducing the baseline assumption (e.g., to 4.3 million truck miles, the

71 A value of 1,400 AADT was chosen as a baseline value for all vehicle traffic by identifying potential
transportation routes to and from the CSS ash basins and selecting the AADT station along the route that
currently has the lowest traffic and would experience the greatest proportional increase in trucking traffic from
ash basin closure. The baseline AADT value (1,400) was then multiplied by the average of large truck traffic
volume (6.9%) in Cleveland and Rutherford Counties to derive an estimated 97 passes per day along the most
sensitive portion of the transportation corridor to and from CSS (Appendix E).
72 The difference of baseline miles and closure option miles was divided by the baseline miles and multiplied by
100 to get a percent impact.

1805958.000 - 2920 54
minimum miles driven in any North Carolina county [Hyde County]) does not appreciably
increase the expected percent impact and relative risk rating and, by extension, the estimated
risk of traffic accidents. Results are summarized in the NEBA framework (
Table 9-4) within the objective of minimizing disturbance to humans during closure.
Table 9-4. Summary of relative risk ratings for attributes that characterize
potential hazards to communities during remediation activities.
Darker shading and higher codes indicate greater impact.
Objective Minimize Human Disturbance
Hazard
Noise and
Traffic
Congestion
Traffic
Accidents
Air
Pollution Potentially Affected Populations Local Residents/Visitors Local Residents/Visitors Reasonable Maximum Exposure Scenario (Unit 5/Active ash basin closure option
Baseline baseline baseline baseline
CIP/CIP 2B 2A --
CIP/Excavation 3B 3A --
CIP/Hybrid 3B 3A --
Excavation/CIP 2B 2A --
Excavation/Excavation 3B 3A --
Excavation/Hybrid 3B 3A --
“--” indicates “no meaningful risk.”

1805958.000 - 2920 55
All closure options create disturbance and risk to human populations, though the estimated
impacts are relatively similar between the closure options based on the trucking projections and
implementation schedules provided by Duke Energy (2018).73
All closure options support safe air quality from diesel truck emissions along the transportation
routes, and each creates a comparable level of disturbance and risk that could adversely impact
community safety. Thus, all closure options similarly satisfy the third objective of ash basin
closure—to minimize risk and disturbance to humans from closure.

73 If for any reason (e.g., safety of personnel at CSS), the basins cannot be c losed simultaneously, the duration of
closure activities would be additive to an unknown degree for each basin, which has not been considered in my
analyses and may change risk ratings and NEBA conclusions.

1805958.000 - 2920 56
10 Conclusion 4: Most closure options for the CSS
ash basins produce no net environmental
disturbance.
Environmental services are derived from ecological processes or functions that have value to
individuals or society, with provision of a healthy environment to humans being one of the most
essential environmental services. Environmental services that support human health include
functions to purify freshwater, provide food, supply recreational opportunities, and contribute to
cultural values (MEA 2005). For example, forests provide habitat for deer that are hunted for
food; surface water supports fish populations that are food for bald eagles, a previously
threatened and endangered species highly valued by our society;74 and soil and wetlands purify
groundwater and surface water, respectively, by adsorbing contaminants. Central to weighing
the net environmental benefits of the closure options under consideration here is understanding
how they differentially impact the variety of environmental services at the site and in the area.
CSS, though an industrial site, supports a diversity of habitats that provide environmental
services. Figure 10-1 illustrates the types of habitats at the site. The ash impoundment provides
habitat that supports birds and mammals; the open water habitat of the impoundment also
removes solids from surface water by providing a low-flow environment in which ash particles
and other solids can settle into the sediment before the treated water can enter the Broad River.
The onsite forest provides biodiversity protection in the form of foraging, shelter, and breeding
habitat for birds and mammals, among other types of organisms; watershed protection;
landscape beauty; and carbon sequestration (Bishop and Landell-Mills 2012). Beyond CSS, the
Broad River provides aquatic habitat that supports a variety of fish and aquatic life (Coughlan et
al. 2010), which then provide food for birds and mammals.

74 Bald eagles were taken off the federal list of threatened and endangered species in 2007
(https://www.fws.gov/midwest/eagle/).

1805958.000 - 2920
57

Figure 10-1. Map of habitat types currently present at CSS

1805958.000 - 2920 58
Plants serve a vital ecosystem role by converting solar energy and carbon dioxide into food (for
themselves) and oxygen. Plants then become food for other organisms. As such, “plants provide
the energy and air required by most life forms on Earth.”75 NPP represents a measure of the
mass of chemically fixed carbon produced by a plant community during a given period and
reflects the rate at which different ecosystems are able to sequester carbon. Given the
foundational role of primary production in supporting ecological food webs and healthy air,
NPP is a good surrogate for environmental services provided by different habitat types
(Efroymson et al. 2003). For example, the annual NPP of a temperate forest habitat is
approximately 2.5 times higher than for temperate grasslands or freshwater ecosystems
(Ricklefs 2008). By multiplying the acres of habitat type by NPP, NPP becomes a single metric
by which to compare the different levels of environmental services impacted by ash basin
closure.76
The fourth objective for ash basin closure, to minimize environmental disturbance, is
represented by the environmental services protection of biodiversity and natural beauty. For
purposes of the NEBA, these considerations were evaluated based on differences in habitat-
derived services estimated from the NPP of impacted habitat acres under the potential closure
options.
10.1 Most closure options produce net gains in environmental
services.
Regardless of the closure option, habitat, and habitat-derived environmental services, will be
altered. CIP closure requires removing existing habitat within the footprint of the ash basin,
possible temporary removal of forest habitat to create a borrow pit to source earthen materials
for the cap, and restoring the ash basin with grass cap habitat. Excavation and onsite landfilling
require temporary loss and future modification of existing habitats within the footprint of the
ash basin and permanent conversion of forest habitat to grass cap at the landfill site. The hybrid
option requires temporary loss and future modification of existing habitats within the footprint

75 https://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOD17A2_M_PSN
76 I used rates of NPP by stand age from He et al. (2012, Figure 2c.) for mixed forests as the basis for establishing
NPP of onsite wooded habitats and used relative rates of NPP from Ricklefs (2008) to scale NPP for other
habitat types.

1805958.000 - 2920 59
of the ash basin. All closure options include restoration of the ash basin footprint, but the
collateral losses of habitat, the differences in service levels of restored habitat, and the timelines
for recovery of the habitats vary based on construction schedules and the acreages and types of
habitat lost or restored. This makes it challenging to appreciate the net gain or loss of
environmental services. To address this challenge, I used a HEA to quantify the differences in
environmental services resulting from each closure option.
HEA is an assessment method widely used in NRDA to facilitate restoration scaling for
environmental services (Dunford et al. 2004; Desvousges et al. 2018; Penn undated). Numerous
damage assessment restoration plans based on the use of HEA can be found on the U.S. Fish
and Wildlife Service77 and NOAA78 websites and include sites such as the St. Lawrence River
near Massena New York, Onondaga Lake near Syracuse New York, and LaVaca Bay in Texas.
As Desvousges et al. (2018) describe, use of HEA has expanded in recent years beyond original
applications for NRDA to address environmental service losses from other causes such as forest
fires and climate change. As the authors note, HEA has also been used as an assessment tool in
NEBA applications, such as evaluating the effects of transmission line routing on habitats of
greater sage-grouse (Centrocercus urophasianus), a proposed threatened species.
The objective of HEA is to estimate the amount of compensatory services necessary to equal the
value of the services lost because of a specific release or incident. The method calculates debits
based on services lost because of resource losses and credits for services gained due to resource
gains. The latter are often scaled to compensate for, or offset, the loss in services. A discount
rate is used to standardize the different time intervals in which the debits and credits occur, so
the services are usually expressed in terms of discounted acre-years of equivalent habitat, or
DSAYs (Dunford et al. 2004; Desvousges et al. 2018; Penn undated).
The HEA methodology was used here to estimate changes in environmental service levels that
will accrue under closure options. Environmental services currently provided by the site will be
eliminated when the ash basin is closed. After closure is complete, there will be a new level of

77 www.doi.gov/restoration
78 www.darrp.noaa.gov

1805958.000 - 2920 60
environmental services provided as habitat is restored. Since post-closure habitats may differ
from those that currently occur onsite, future services could be greater or less than what occurs
at present. Similarly, land used as a borrow area or converted to landfill, as per the closure
options, will also impact the net level of services, as services currently provided by those
habitats may be reduced. The environmental service losses and gains from onsite and offsite
habitats must be considered together when determining the overall net effect of a closure option.
A common ecological metric is required to make comparisons between service gains and losses
from various habitat types. For purposes of this evaluation, I used annual NPP as the metric to
standardize across habitat types. In terms of habitats currently occurring on the site, wooded
areas have the highest NPP, so that is used as the basis for defining service level, and the service
levels for other habitat types (open fields, open water) are expressed as a proportion of that
baseline service. Based on He et al. (2012), and assuming a tree stand age of 50 years, NPP
would be approximately 6.4 tons of carbon per hectare per year (6.4 t C/ha/yr) in wooded areas
onsite. Based on relative rates of NPP from Ricklefs (2008), the NPP for open field and open
water habitats would be approximately 40% of the temperate forest rate. To prevent
overestimation of NPP in open water areas of the ash basin that may not provide the same level
of NPP as natural freshwater habitats (perhaps from limited abundance or diversity of
vegetation), I assumed that open water areas of the ash basin produce NPP that is 25% that of
natural ecosystems.79 Therefore, I applied a four-fold habitat quality factor to scale NPP at these
open water areas of the ash basin to approximately 10% of the rate for wooded habitats.
Deforested land for borrow areas was assumed to be reforested after closure was complete, and
landfill areas were assumed to recover to grass cap. The grass cap on landfill was given a
service value of 8%,80 as was done for CIP.

79 I observed open water areas of the ash basin that supported aquatic vegetation but do not kn ow the extent of
vegetation in the open water areas of the ash basin. Thus, I made a conservative assumption (i.e., one that
reduces the present value of the habitat) that these areas of the ash basin provide a reduced level of NPP
compared to natural open freshwater areas.
80 An open field provides a relatively lower NPP service level than forest habitat (40% of forest NPP; Ricklefs
2008), and since a grass cap requires periodic maintenance mowing, for purposes of the HEA it was assumed
never to reach a level of NPP service equivalent to an open field. Grass cap was assumed to have 20% of the
NPP service level for open field, which is 8% of forest NPP.

1805958.000 - 2920 61
For each closure option, I used the acreage of existing habitat types and the level of service of
that habitat type to establish a baseline level of service. Based on the timelines for the various
closure options, a HEA was conducted to calculate the net change in service flow of the closure
area over the next 150 years at a 3% discount rate.81 Similarly, a HEA was run to calculate the
net change in environmental services deriving from areas used either as borrow or for landfill.
Because NPP standardizes service levels across habitat types, the DSAY estimates for all
affected habitats can be summed to calculate the net service gain/loss associated with each
closure option. In addition to the assumptions identified above, several other assumptions were
made to support the HEA, which are described in Appendix D.
Results of the HEA are presented in Table 10-182 and indicate that all but one closure option for
the ash basins at CSS result in a net gain in NPP services. Only, CIP closure of both the Unit 5
inactive basin and active ash basin (CIP/CIP) will result in a net loss of environmental services
due primarily to the reduced NPP services provided by the grass cap that will replace all of the
existing habitats in the inactive ash basin and most of the existing habitats in the active basin.
This factor adversely affects the environmental services provided by the ash-impacted habitat
such that environmental services produced after closure will not compensate for the service
losses resulting from the closure. Excavation closures produce the largest net gain in
environmental services because of the amount of forested land that will be restored within both
basins and the relatively smaller footprint of the new landfill compared to the restored ash basin
area.

81 Environmental services in future years are discounted, which places a lower value on benefits that will take
longer to accrue. The basis for this is that humans place greater value on services in the present and less value
on services that occur in the future.
82 A full description of the methods, assumptions, results, and sensitivity analyses for the HEA are provided in
Appendix D.

1805958.000 - 2920
62
Table 10-1. Summary of NPP DSAYs for closure options (Unit 5 Inactive Basin Closure/Active Basin Closure)
CIP/CIP CIP/Excavation CIP/Hybrid Excavation/CIP Excavation/Excavation Excavation/Hybrid
Ash basin losses Open field −334 −334 −334 −334 −334 −334

Grass Cap −83 −83 −83 −101 −101 −101

Open Water −114 −114 −114 −113 −113 −113

Wetland
Broadleaf Forest −172 −172 −172 −181 −181 −181
Needleleaf Forest −79 −79 −79 −79 −79 −79
Scrub/Shrub −150 −150 −150 −205 −205 −205
Wetland Forest −24 −24 −24 −24 −24 −24

Total onsite losses −955 −955 −955 −1,037 −1,037 −1,037
Ash basin post-closure gains Open field 53 53 53

Grass Cap 273 104 226 169 121

Open Water

Wetland
Broadleaf Forest 339 1541 617 1,126 2,329 1,404
Needleleaf Forest 116 528 211 385 797 481
Scrub/Shrub 82 82 82
Wetland Forest 3 16 6 12 24 14

Total onsite gains 731 2,189 1,060 1,827 3,284 2,156
Landfill/borrow losses Forest −29 −1,200 −29 −556 −1,727 −556

Open field
Grass Cap −4 −4

Total offsite losses −33 −1,200 −29 −560 −1,727 −556
Landfill/borrow post-closure gains Forest 23 23 23

Open Field
Grass Cap 3 75 42 114 39

Total offsite gains 26 98 23 42 114 39
Net Gain/Loss per Option −231 132 99 272 634 601
Note: DSAYs for specific habitat types are reported here rounded to the nearest whole number. As such, the net gain/loss per option differs slightly from the sum of the indivi dual
DSAYs reported in the table.
Closure duration estimates assume simultaneous closure of the EAB and WAB. A construction feasibility analysis of this assumption has not been conducted. If the basins were to be
closed sequentially, the duration of the estimated closure for each option would be substantially longer and change the results of the HEA.

1805958.000 - 2920 63
10.2 NEBA – Minimize Environmental Disturbance
The impact of the closure options on environmental services was computed as the percentage
difference in DSAYs produced by the closure option and the absolute value of the DSAY losses.
The DSAY losses represent the NPP services that would have been produced by the site, borrow
areas, and landfills but for the project closure. The DSAY gains represent the NPP services
restored after project closure plus any future gains realized from existing habitats before
remediation begins. The sum of DSAY losses and gains represents the net change of NPP
services for the project resulting from closure. Dividing the net DSAYs by the absolute value of
the DSAY losses provides a percentage of the impact. From these calculations, CIP closure of
both basins (CIP/CIP) will have a 23% impact,83 while all other closure options will have no net
adverse impact on NPP services and will, in fact, increase net NPP services (Table 10-2). These
percent impacts were input to the risk-ranking matrix (Table 5-4) along with the duration of the
closure activities84 (see Table 4-1) to evaluate, within the NEBA construct, which of the closure
options best minimizes environmental disturbances (Table 10-3).
Table 10-2. Percent impact of ash basin closure options.
Unit 5 basin closure/Active ash basin closure.
CIP/CIP
CIP/
Excavation
CIP/
Hybrid
Excavation/
CIP
Excavation/
Excavation
Excavation/
Hybrid
DSAY Lossesa 988 2,155 984 1,597 2,764 1,593
DSAY Gains 757 2,287 1,083 1,869 3,398 2,194
Percent Impact (%) 23% 0% 0% 0% 0% 0%
a Absolute value of DSAY losses is equivalent to baseline services of the affected habitat but for the closure

83 Note, however, that the environmental services lost due to CIP closure of both basins could be offset (see
discussion in Section 11) by a suitable reforestation project that would then result in all closure options causing
no net loss of habitat-derived environmental services in the HEA model.
84 As noted previously, estimates of the duration of closure and construction assume that both the Unit 5 inactive
ash basin and the active ash basin can be closed simultaneously, an assumption that has not received a
feasibility analysis. If for any reason (e.g., safety of personnel at CSS), the basins cannot be closed
simultaneously, the duration of closure activities would be additive for each basin and the results of the HEA
would change.

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Table 10-3. Summary of relative risk ratings for habitat changes that
affect provision of environmental services.
Darker shading and higher codes indicate greater impact.
Objective
Minimize Environmental
Disturbance
Hazard Habitat Change
Attribute DSAYs
Scenario (Unit 5/Active ash basin closure option
Baseline baseline
CIP/CIP 2C
CIP/Excavation --
CIP/Hybrid --
Excavation/CIP --
Excavation/Excavation --
Excavation/Hybrid --
“--” indicates “no meaningful risk.”
Within the objective of minimizing environmental disturbance from closure, my analyses
indicate that all but one closure option produce a net benefit in habitat-derived environmental
services; CIP closure of both basins (CIP/CIP) slightly decreases habitat-derived environmental
services. Thus, all closure options except CIP/CIP satisfy the fourth objective of ash basin
closure—to minimize risk and disturbance to the environment from closure.85

85 If for any reason (e.g., safety of personnel at CSS), the basins cannot be closed simultaneously, the duration of
closure activities would be additive to an unknown degree for each basin, which has not been considered in my
analyses and may change risk ratings and NEBA conclusions

1805958.000 - 2920 65
11 Conclusion 5: Most closure options for the CSS
ash basins produce comparable environmental
services.
Identifying environmental actions that maximize environmental services (the fifth objective for
ash basin closure) is a function of NEBA (Efroymson et al. 2003, 2004) and the overarching
objective that encompasses each of the other four objectives and all of the environmental
services that have been considered to this point. Table 11-1 summarizes the relative risk ratings
for all attributes and objectives. Impacts to environmental services considered in this NEBA
focused on key community-relevant concerns. Risk to construction workers from construction
operations, risks to local and global populations from increased greenhouse gas emissions, and
“wear-and-tear” damage to roadways from trucking were not estimated. Each of these risks,
however, would scale with the duration, frequency, and intensity of construction operations.
Sensitivity analyses of the specifications of the NEBA framework show that the specific relative
risk ratings presented in this NEBA can change depending on how baseline is defined (see
Appendix E). The purpose of the risk matrix, and the risk ratings that result from it, is to
consolidate the results from a variety of different analyses for a variety of different data types
and attributes into a single framework for comparative analysis. It is imperative, however, to
consider the underlying information used to develop the risk ratings to interpret the differences
between closure options, particularly when percent impacts or durations of closure options are
similar but receive different risk ratings.
As noted in Section 5, NEBA analysis provides an opportunity to better understand the net
environmental benefits of possible closure options. If Duke Energy’s preferred closure option
for reasons not considered in the NEBA does not best maximize environmental services to the
local community as currently defined, the NEBA results provide insight into how environmental
services could be improved for that closure option. For instance, if Duke Energy’s preferred
closure option for CSS is CIP closure of both basins but the HEA results for the currently
defined CIP closure option estimates a net environmental service loss of 231 DSAYs, Duke
Energy could consider incorporating into an updated CIP closure plan for CSS a mitigation

1805958.000 - 2920 66
project that compensates for the net environmental service losses projected from the currently
defined CIP closure option. As an example, if Duke Energy started a reforestation project
outside of the ash basin in 2023 (when onsite preparation of the ash basins begins), the
reforestation project would gain 23.6 DSAYs/acre over the lifetime of the site (150 years in the
HEA), requiring an approximate 9.8 acre project to compensate for the 231 DSAY loss
projected in the HEA. Re-analysis of the HEA component of the NEBA for the updated possible
closure options would then result in no net environmental losses (as NPP services) from habitat
alteration of the basins for any currently defined closure options.
From the closure options considered and the analyses presented in this report, which are based
on a scientific definition of risk acceptability and include no value weighting, all closure options
as currently defined except CIP closure of both the Unit 5 inactive basin and the active basin
(CIP/CIP) produce comparable environmental benefits because they offer equivalent protection
of human and ecological health from CCR exposure, similar levels of disturbance to humans,
and net gains in habitat-derived environmental services. Thus, all closure options except CIP of
both basins (CIP/CIP) provide comparable net environmental services and disturbance to the
community, similarly satisfying the fifth objective of ash basin closure—to maximize local
environmental services.86

86 If for any reason (e.g., safety of personnel at CSS), the basins cannot be closed simultaneously, the duration of
closure activities would be additive to an unknown degree for each basin, which has not been considered in my
analyses and may change risk ratings and NEBA conclusions

1805958.000 - 2920
67
Table 11-1. NEBA for closure of the ash basin at CSS.
Darker shading and higher alphanumeric codes indicates greater impact.
Objective Protect Human Health from
CCR
Protect Ecological Health from
CCR Minimize Human Disturbance
Minimize
Environmental
Disturbance
Hazard Exposure to CCR Exposure to CCR
Noise and
Traffic
Congestion
Traffic
Accidents
Air
Pollution Habitat Change Potentially Affected Populations Local Residents/Visitors Onsite Construction Workers Offsite Recreational Swimmers Offsite Recreational Waders Offsite Recreational Boaters Offsite Recreational Fishers Offsite Subsistence Fishers Fish Populations Aquatic Omnivore Birds (mallard) Aquatic Piscivore Birds (great blue heron) Aquatic Herbivore Mammals (muskrat) Aquatic Piscivore Mammals (river otter) Local Residents/Visitors Local Residents/Visitors Reasonable Maximum Exposure DSAYs
Scenario (Unit 5/Active ash basin closure option
Baseline -- -- -- -- -- -- -- -- -- -- -- baseline baseline baseline baseline
CIP/CIP -- -- -- -- -- -- -- -- -- -- -- 2B 2A -- 2C
CIP/Excavation -- -- -- -- -- -- -- -- -- -- -- 3B 3A -- --
CIP/Hybrid -- -- -- -- -- -- -- -- -- -- -- 3B 3A -- --
Excavation/CIP -- -- -- -- -- -- -- -- -- -- -- 2B 2A -- --
Excavation/Excavation -- -- -- -- -- -- -- -- -- -- -- 3B 3A -- --
Excavation/Hybrid -- -- -- -- -- -- -- -- -- -- -- 3B 3A -- --
“--” indicates “no meaningful risk.”

1805958.000 - 2920 68
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Appendix A

Curriculum Vitae of
Dr. Ann Michelle Morrison, Sc.D.

Ann Michelle Morrison, Sc.D.
12/17 | Page 1

Professional Profile
Dr. Morrison has over 20 years of experience evaluating the relationship between anthropogenic
contamination and health effects to aquatic life and humans. Dr. Morrison specializes in natural resource
damage assessment (NRDA), environmental causal analysis, and assessments of water quality
conditions. Dr. Morrison has provided scientific consultation regarding the design of field studies for
NRDA, and she has worked closely with legal counsel during scientific assessments and settlement
negotiations with state and federal trustees. Dr. Morrison has performed detailed technical assessments
of injuries to aquatic resources, including vegetation, benthic infauna, fishes, shellfishes, and corals. She
has also developed site-specific sediment toxicity thresholds based on the empirical r elationships of
chemical concentrations to biological effects. She has provided expert testimony concerning injury to
aquatic resources and the net environmental benefits of remediation alternatives .

Projects she has been involved with have concerned oil spills, sewage releases, heavy metal
contamination, and various industrial and municipal facilities that have generated complex releases to the
environment. Dr. Morrison applies statistical tools and weight-of-evidence approaches to delineate
exposure zones, predict the likelihood of contamination events, evaluate net environmental benefits, and
assess causation. She uses a broad knowledge of aquatic life and human health to assess risk and injury
to these populations.
Academic Credentials & Professional Honors
Sc.D., Environmental Health, Harvard University, 2004

M.S., Environmental Health, Harvard University, 2001

B.S., Biology, Rhodes College, 1997
Prior Experience
Senior Scientist, Sole Proprietor, Morrison Environmental Data Services, 2004 –2007

Data Analyst, ETI Professionals, 2005

Scientist, NIH Toxicology Training Grant, Harvard School of Public Health, 2000 –2004

Guest Student, Woods Hole Oceanographic Institution, Stegeman Lab, 2001–2004

Science Intern, Massachusetts Water Resources Authority, 03-05/2000, 10/2000-10/2001

Ann Michelle Morrison, Sc.D.
Senior Managing Scientist | Ecological & Biological Sciences
1 Mill and Main Place, Suite 150 | Maynard, MA 01754
[phone] tel | [e-mail]

Ann Michelle Morrison, Sc.D.
12/17 | Page 2
Research technician, Bermuda Biological Station for Research, Inc., Benthic Ecology Research Program
(BERP), Bermuda, 01/1998-09/1999, 06-08/2000

Research Intern, Bermuda Biological Station for Research, Inc., Benthic Ecol ogy Research Program
(BERP), Bermuda, 05/1997-12/1997

NSF Research Experience for Undergraduates Fellowship, Bermuda Biological Station for Research, Inc.,
Benthic Ecology Research Program (BERP), Bermuda, 08-11/1996
Professional Affiliations
American Chemical Society — ACS

Society for Risk Analysis — SRA

Society of Environmental Toxicology and Chemistry — SETAC

North Atlantic Chapter of SETAC
Publications
Mearns AJ, Reish DJ, Bissell M, Morrison AM, Rempel-Hester MA, Arthur C, Rutherford N, Pryor R.
Effects of pollution on marine organisms. Water Environment Research 2018; 90(10):1206–1300.
Mearns AJ, Reish DJ, Oshida PS, Morrison AM, Rempel-Hester MA, Arthur C, Rutherford N, Pryor R.
Effects of pollution on marine organisms. Water Environment Research 2017; 89(10):1704–1798.

Morrison AM, Edwards M, Buonagurio J, Cook L, Murray K, Boehm P. Assessing the representativeness
and sufficiency of water samples collected during an oil spill. Proceedings, 2017 International Oil Spill
Conference, Vol 2017, No 1.

Mearns AJ, Reish DJ, Oshida PS, Morrison AM, Rempel-Hester MA, Arthur C, Rutherford N, Pryor R.
Effects of pollution on marine organisms. Water Environment Research 2016; 88(10):1693–1807.

Morrison AM, Kashuba R, Menzie CA. Evaluating alternative causes of environmental change.
Environmental Perspectives 2016; 1.

Boehm PD, Morrison AM, Semenova S, Kashuba R, Ahnell A, Monti C. Comprehensive oil spill liability
estimation. Environmental Perspectives 2016; 1.

Boehm PD, Morrison AM. Oil spill liability modeling: helping to manage existential risks. Oil & Gas Insight,
2016; 4.

Morrison AMS, Goldstone JV, Lamb DC, Kubota A, Lemaire B, Stegeman JJ. Identification, modeling and
ligand affinity of early deuterostome CYP51s, and functional characterization o f recombinant zebrafish
sterol 14α-demethylase. Biochimica et Biophysica Acta, 2014; 1840:1825 –1836.

Menzie C, Kane Driscoll SB, Kierski M, Morrison AM. Advances in risk assessment in support of sediment
risk management. In: Processes, Assessment and Remediation of Contaminated Sediments. Reible DD
(ed), SERDP ESTCP Environmental Remediation Technology, Vol. 6, pp. 107–130, 2014.

Mudge S, Morrison AM. Tracking sources of sewage in the environment. Environmental Forensic Notes,
2010; 9.

Ann Michelle Morrison, Sc.D.
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Pietari J, Bigham G, Morrison AM. Source tracking for identification of microbial pollution sources.
Environmental Forensic Notes, 2009; 6.

Goldstone JV, Goldstone HMH, Morrison AM, Tarrant AM, Kern SE, Woodin BR, Stegeman JJ.
Cytochrome P450 1 genes in early deuterostomes (tunicates and sea urchins) and vertebrates (chicken
and frog): Origin and diversification of the CYP1 gene family. Molecular Biology and
Evolution 24(12):2619–31, 2007.

Morrison AM. Receiver Operating Characteristic (ROC) Curve Analysis of Antecedent R ainfall and the
Alewife/Mystic River Receiving Waters. Boston: Massachusetts Water Resources Authority. Report
ENQUAD 2005-04, 2005. 26 p.

Morrison AM, Coughlin K. Results of intensive monitoring at Boston Harbor beaches, 1996–2004. Boston,
Massachusetts Water Resources Authority, Report ENQUAD 2005-05, 76 pp., 2004.

Morrison AM, Coughlin K, Shine JP, Coull BA, Rex AC. Receiver operating characteristic curve analysis
of beach water quality indicator variables. Applied and Environmental Microbiology, 2003 ; 69:6405–6411.

Coughlin K, Stanley AM. Boston Harbor beach study suggests a change in beach management.
Coastlines, 2001; Issue 11.6.

Coughlin K, Stanley AM. Water quality at four Boston Harbor beaches: Results of intensive monitoring
1996–2000. Boston, Massachusetts Water Resources Authority, Report ENQUAD 2001-18, 46 pp., 2001.

Published Abstracts

Stegeman J, Handley-Goldstone H, Goldstone J, Tarrant A, Morrison AM, Wilson J, Kern S. Pantomic
studies in environmental toxicology answers, questions and extrapolation. Journal of Experimental
Zoology Part a-Comparative Experimental Biology, 2006; 305A:181.

Goldstone JV, Goldstone HMH, Morrison AM, Tarrant A, Kern SE, Woodin BR, Stegeman JJ. Functional
evolution of the cytochrome P450I gene family: Eviden ce of a pre-vertebrate origin. Marine Environmental
Research, 2006; 62: S47

Handley HH, Goldstone JV, Morrison AM, Tarrant, Wilson JY, Godard CA, Woodin BR, Stegeman JJ.
Abstracts from the 12th International Symposium on Pollutant Responses in Marine Orga nisms (PRIMO
12) — Receptors and Regulation of Cytochrome P450. Marine Environmental Research, 2004; 58:131+.

Morrison AM, Stegeman JJ. Abstracts from the Twelfth International Symposium on Pollutant Responses
in Marine Organisms (PRIMO 12) — Cloning, Expression and Characterization of Cytochrome P450 51:
An investigation of CYP51 azole sensitivity in aquatic animals. Marine Environmental Research, 2004;
58:131+.

Morrison AM, Stegeman JJ. CYP51 azole sensitivity in lower vertebrates and invertebrate. Drug
Metabolism Reviews: Biotransformation and Disposition of Xenobiotics, 2003; 35(2):179.

Presentations

Morrison AM, Ma J, Gard N, Palmquist K, Lin C, Deines A. Ecosystem services accounting in support of
corporate environmental stewardship in a changing climate. Society of Environmental Toxicology and
Chemistry (SETAC) North America 39th Annual Meeting, Sacramento, CA. November 5–8, 2018.
Pietari J, Morrison AM, Kashuba R, Boehm PD. Incorporating a framework for risk assessment, risk
management, and risk mitigation of extreme weather events at Superfund sites. Society of Environmental

Ann Michelle Morrison, Sc.D.
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Toxicology and Chemistry (SETAC) North America 39th Annual Meeting, Sacramento, CA. November 5–
8, 2018.
Deines AM, Palmquist K, Morrison AM. Global Status and Risk of Non-Native Fish Aquaculture. 148th
Annual Meeting of the American Fisheries Society, Atlantic City, NJ. August 19–23, 2018.
Morrison AM, Palmquist K, Kashuba R. Baseline in the Open-Access and “Big Data” Era. Law Seminars
International. Washington, D.C. March 1, 2018.
Palmquist K, Morrison AM, Edwards ME. Addressing white hat bias: Lessons from environmental
litigation. Society of Environmental Toxicology and Chemistry (SETAC) North America 38th Annual
Meeting, Minneapolis, MN. November 12–16, 2017.

Palmquist KR, Ginn TC, Morrison AM, Boehm PD. 2017. Addressing Spatial Data Gaps in Deep-sea
Benthic Sediment Sampling Following a Large-Scale Oil Spill. Battelle Sediment Conference in New
Orleans, LA.

Morrison AM. The Science. Natural Resource Damages 101. Law Seminars International. Washington,
D.C. March 9, 2016.

Morrison AM, Murray KJ, Cook LC, Boehm PD. Spatial and Temporal Extent of PAHs Associated with
Surface Oil Distributions (Anomalies). Gulf of Mexico Research Initiative Conference. Tampa, F L.
February 1–4, 2016.

Boehm PD, Morrison AM. The Interplay of Data Needs and Data Analysis Frameworks to Optimize the
Collection and Use of Data from Oil Spills. Gulf of Mexico Research Initiative Conference. Tampa, F L.
February 1–4, 2016.

Whaley JE, Morrison AM, Savery LC. Using the Causal Analysis Framework to Investigate Marine
Mammal Unusual Mortality Events (poster), Society of Marine Mammalogy Biennial Conference, San
Francisco, CA. December 2015.

Kashuba R, Morrison AM, Menzie C. The Application and Misapplicat ion of Directed Acyclic Graphs for
Causal Inference in Ecology. Society of Environmental Toxicology and Chemistry (SETAC) North America
36th Annual Meeting, Salt Lake City, UT. November 1–5, 2015.

Kierski M, Morrison AM, Kane Driscoll S, Menzie C. A Refined Multi-Site Model to Estimate the Toxicity of
PAH-Contaminated Sediments at MGP Sites. Society of Environmental Toxicology and Chemistry
(SETAC) North America 36th Annual Meeting, Salt Lake City, UT. November 1–5, 2015.

Morrison AM, McArdle M, Menzie C. A Tiered Approach to Causal Analysis in Natural Resource Damage
Assessment. 35th Annual Society of Environmental Toxicology and Chemistry (SETAC) Meeting,
Vancouver, BC, Canada. November 9–13, 2014.

Morrison AM, Kane Driscoll S, McArdle M, Menzie C. Integrated environmental benefit analysis of
sediment remediation thresholds. 32nd Annual Society of Environmental Toxicology and Chemistry
(SETAC) Meeting, Boston, MA. November 14–17, 2011.

Kierski M, Morrison AM, Kane Driscoll S, Menzie C. A multi-site model to estimate the toxicity of PAH
contaminated sediments at MGP sites. 32nd Annual Society of Environmental Toxicology and Chemistry
(SETAC) Meeting, Boston, MA. November 14–17, 2011.

Kierski M, Morrison AM, Kane Driscoll S, Menzie C. Use of receiver operating characteristic curve
analysis to estimate ecological risk zones as part of an ecological risk assessment. 31st Annual Society

Ann Michelle Morrison, Sc.D.
12/17 | Page 5
of Environmental Toxicology and Chemistry (SETAC) Meeting, Portland, OR. November 7–11, 2010.

Morrison AM, Coughlin K, Rex A. Bayesian network predictions of Enterococcus exceedances at four
Boston Harbor beaches. Water Resources Conference 2008, Amherst, MA . April 8, 2008.

Stegeman J, Handley-Goldstone H, Goldstone J, Tarrant A, Morrison AM, Wilson J, Kern S. Pantomic
studies in environmental toxicology answers, questions and extrapolation. 15th International Congress of
Comparative Endocrinology, Boston, MA. 2005.

Goldstone JV, Goldstone HMH, Morrison AM, Tarrant A, Kern SE, Woodin BR, Stegeman JJ. Functional
evolution of the cytochrome P450I gene family: Evidence of a pre-vertebrate origin. 13th International
Symposium on Pollutant Responses in Marine Organisms (PRIMO 13), Alessandria, Italy, June 2005.

Morrison AM, Stegeman JJ. CYP51 azole sensitivity in lower vertebrates and invertebrate. 12th North
American Meeting of the International Society for the Study of Xenobiotics, Providence, RI . October 12–
16, 2003.

Morrison AM, Stegeman JJ. Cloning, expression and characterization of Cytochrome P450 51: An
investigation of CYP51 azole sensitivity in aquatic animals. 12th International Symposium, Pollutant
Responses in Marine Organisms, Tampa, FL. May 2003.

Handley HH, Goldstone JV, Morrison AM, Tarrant AM, Wilson JY, Godard CA, Woodin BR, Stegeman JJ.
12th International Symposium, Pollutant Responses in Marine Organisms, Tampa, FL. May 2003.

Morrison AM, Coughlin KA, Shine JP, Coull BA, Rex AC. Receiver operating characteristic curve analysis
of beach water quality indicator variables. Pathogens, Bacterial Indicators, and Watersheds: Treatment,
Analysis, Source Tracking, and Phase II Stormwater Issues. New England Watershed Association,
Milford, MA. May 14, 2003.

Stanley AM, Coughlin KA, Shine JP, Coull BA, Rex AC. Receiver operating characteristic analysis is a
simple and effective tool for using rainfall data to predict bathing beach bacterial water quality. 102nd
General Meeting, American Society for Microbiology, Salt Lake City, UT . May 2002.

Coughlin K, Stanley AM. Five years of intensive monitoring at Boston harbor beaches: Overview of beach
water quality and use of the Enterococcus standard to predict water quality. Massachusetts Coastal Zone
Marine Monitoring Symposium, Boston, MA. May 2001.

Smith SR, Grayston LM, Stanley AM, Webster G, McKenna SA. CARICOMP coral reef monitoring: A
comparison of continuous intercept chain and video transect techniques. Scientific Aspects of Coral Reef
Assessment, Monitoring and Management, National Coral Reef Institute (NCRI), Nova Southeastern
University, Ft. Lauderdale, FL. 1999.
Project Experience
Dr. Morrison has been involved in numerous complex projects relating to environmental contamination
and potential risk to humans and biological resources in the affected environment.

Risk Assessments and Natural Resource Assessments

Expert witness concerning net environmental benefits from coal ash closure alternatives at two coal ash
plants in North Carolina. Roanoke River Basin Association v. Duke Energy Progress, LLC, United States
District Court, Middle District of North Carolina, Case No. 1:16-cv-607 and Roanoke River Basin
Association v. Duke Energy Progress, LLC, United States District Court, Middle District of North Carolina,
Case No. No. 1:17-cv-452.

Ann Michelle Morrison, Sc.D.
12/17 | Page 6

Expert witness concerning potential damages to terrestrial and aquatic resources, including coral reefs,
endangered sea turtles, fish and shellfish, and seagrass beds, resulting from a coastal development
project on the Caribbean island of Nevis. Anne Hendricks Bass vs. Director of Physical Planning,
Development Advisory Committee, and Caribbean Development Consultant Limited. Eastern Caribbean
Supreme Court, in the High Court of Justice Saint Christopher and Nevis, Nevis Circuit, Civil Case No.
NEVHCV2016/0014.

Expert witness concerning potential impacts to California fishery populations from the Refugio oil spill.
Andrews et al. v. Plains All American Pipeline, L.P. et al. United States District Court, Central District of
California, Wester Division, Case No. 2:15-cv-04113-PSG-JEM.

Provided analysis and technical support in Florida v. Georgia United States Supreme Court case that
considered questions of causation relative to alleged adverse ecological changes in downstream river
and bay populations.

Conducted a comprehensive review of an environmental impact assessment of potential impacts to coral
reefs from a proposed dairy farm development in Hawaii.

Provided scientific support for the Deepwater Horizon NRDA in the Gulf of Mexico.

Developed a cooperative NRDA field study in the offshore waters of the Gulf of Mexico to collect
sediment samples for analysis of chemistry, toxicology, and benthic infauna.

Expert witness concerning alleged injuries to aquatic resources from disposal of bauxite ore processing
wastes for the case: Commissioner of the Department of Planning and Natural Resources, Alicia V.
Barnes, et al. v. Virgin Islands Alumina Company et al. District Court of the Virgin Islands, Division of St.
Croix, Civil Case No. 2005-0062.

Developed decision management products for beach water quality stakeholders using statistical data
analysis tools such as receiver operating characteristic (ROC) curves and Bayesian networks to improve
public beach advisories related to elevated fecal bacteria.

Developed net environmental benefit analysis (NEBA) for a lead contaminated river. This analysis used
site-specific data to evaluate the costs and benefits of two different remediation options that were being
considered. The NEBA was successfully used by the client to negotiate a higher remediation goal than
original proposed by the state Department of Environmental Protection.

Performed ROC curve analyses of site-specific polycyclic aromatic hydrocarbon (PAH) toxicity data to
assess the relationship between PAH concentration and toxicity at three ecological risk assessment
projects in Wisconsin. The curves were used to identify site-specific toxicity thresholds for PAH
concentration in sediment that were indicative of various zones of toxicity (no toxicity, low tox icity, and
high toxicity), with very limited misidentification of sediments.

Provided research support to calculate site-specific no-observed-adverse-effect level (NOAEL) and
lowest-observed-adverse-effect level (LOAEL) concentrations for mammals and birds for use in a
baseline ecological risk assessment in Wisconsin.

Performed ROC curve analysis of national mercury toxicity data to assess the relationship between
mercury concentration and toxicity. The curves were also used to identify a threshold mercur y
concentration for sediment that indicates likely toxicity, with very limited misidentification of sediments that
are not toxic.

Assembled and analyzed data and reviewed remedial investigations to conduct a screening-level

Ann Michelle Morrison, Sc.D.
12/17 | Page 7
ecological risk assessment for sediment, surface water, and groundwater for a site in Connecticut. The
chemicals considered were total petroleum hydrocarbons (TPH), metals, and PAHs.

Reviewed species lists and created summary descriptions of organisms that could be potentially impacted
by dam construction on a high-altitude river in the Caribbean. This information was important to develop
the risk assessment from dam construction.

Researched the toxicity of malathion to fish to support a technical review of the National Marine Fisherie s
biological opinion for the registration of pesticides containing malathion.

Ecological and Toxicity Studies

Conducted surveys to assess the health of coral reefs, seagrass beds, and mangrove swamps in the
nearshore environment of Bermuda. Projects included area-wide habitat surveys as well as targeted sites
potentially impacted by a heavy metals dump, hot water effluent from an incinerator, sedimentation from
cruise ship traffic, and chronic release of raw sewage. In addition to ecological surveys, wate r quality was
assessed through measurements of trace metals in water, sediment, and coral tissue.

Surveyed juvenile coral recruitment in the Florida Keys to evaluate if marine protected areas (MPA s)
provide a benefit to coral recruitment.

Studied cytochrome P450 family enzymes, including CYP51 and CYP1, examining their sensitivity to
environmental chemicals and their evolution through molecular biology and biochemistry approaches.

Environmental Forensics Projects

Performed document review, information m anagement, and technical writing for numerous complex
projects that dealt with historical petroleum contamination and multiple site owners in several types of
environmental media.

Reviewed documents, assembled data, and researched metal concentrations associated with crude oil
and railroads in support of a Superfund project in Oklahoma.

Examined the correlation of multiple contaminants (PAHs, metals) with polychlorinated biphenyl (PCB)
congeners at a historically contaminated site in Alabama to identify the likely origins of the PCB
contamination.

Performed statistical analysis to determine source contribution in a chemical fingerprinting case at a
Superfund site in Washington that involved hydrocarbons in water, sediment, and groundwater.

Human Health Projects

Organized, managed, and simplified a complex database of field sampling reports for a litigation case in
Louisiana regarding human air exposure to PAHs.

Performed data analysis and document review for a Superfund site in Oklahoma. The analyses us ed
hydrocarbon chromatograms and limited PAH and metal data to identify the likely sources of
contamination.

Researched and compiled screening-level human health inhalation toxicity values for refinery-related
gases for an overseas project.

Developed a questionnaire and related database for industrial hygiene surveys to support regulatory
compliance for a highly specialized industry.

Appendix B

Human Health and Ecological
Risk Assessment Summary
Update for Cliffside Steam
Station

Matt Huddleston, Ph.D.
Senior Scientist
Heather Smith
Environmental Scientist

HUMAN HEALTH AND
ECOLOGICAL RISK ASSESSMENT
SUMMARY UPDATE
FOR

CLIFFSIDE STEAM STATION
573 DUKE POWER ROAD
MOORESBORO, NORTH CAROLINA 28114
NOVEMBER 2018
PREPARED FOR
DUKE ENERGY CAROLINAS, LLC
526 SOUTH CHURCH STREET
CHARLOTTE, NORTH CAROLINA 28202

Risk Assessment Summary Update November 2018
Cliffside Steam Station SynTerra

Page 1
1.0 INTRODUCTION
This update to the Cliffside Steam Station (CSS or Site) human health and ecological
risk assessment incorporates results from sampling events conducted August 2008
through August 2018. The samples were collected from surface water, sediment, and
groundwater. This update was performed in support of a Net Environmental Benefits
Analysis. As set forth below in detail, this updated risk assessment concludes that: (1)
the CSS ash basins do not cause any material increase in risks to human health for
potential human receptors located on-Site or off-Site; and (2) the CSS ash basins do not
cause any material increase in risks to ecological receptors.
The original 2016 risk assessment was a component of the Corrective Action Plan Part 2
pertaining to CSS (HDR, 2016). To assist in corrective action decision making, the risk
assessment characterized potential effects on humans and wildlife exposed to naturally
occurring elements, often associated with coal ash, present in environmental media.
Corrective action is to be implemented with the goal of ensuring future site conditions
remain protective of human health and the environment, as required by the 2014 North
Carolina General Assembly Session Law 2014-122, Coal Ash Management Act (CAMA).
The risk assessment was updated as part of the 2018 Comprehensive Site Assessment
(CSA) Update report (SynTerra, 2018). This update follows the methods of the 2016 risk
assessment (HDR, 2016) and is based on U.S. Environmental Protection Agency
(USEPA) risk assessment guidance (USEPA, 1989; 1991; 1998).
Areas of wetness (AOWs), or seeps, are not subject to this risk assessment update.
AOWs associated with engineered structures, also referred to as “constructed seeps,”
have been addressed in a National Pollutant Discharge Elimination System (NPDES)
permit. Other AOWs (non-constructed seeps) are now addressed under a Special Order
by Consent (SOC) issued by the North Carolina Environmental Management
Commission (EMC SOC WQ S17-009). Many AOWs are expected to reduce in flow or
be eliminated after decanting (i.e., removal of the free water). The SOC requires that
any seeps remaining after decanting must be addressed with a corrective action plan
that must ”protect public health, safety, and welfare, the environment, and natural
resources” (EMC SOC WQ S17-009, 2. d.).
This risk assessment update includes results from samples of surface water, sediment,
and groundwater collected since the 2018 CSA update. New information regarding
groundwater flow and the treatment of source areas other than the ash basins has
resulted in refinement of exposure pathways and exposure areas. The Conceptual Site
Models (CSMs) (Figures 1 and 2) reflect potentially complete exposure pathways with
potential risks, and ecological exposure areas are depicted in Figure 3. Human health
Risk Assessment Summary Update November 2018
Cliffside Steam Station SynTerra

Page 2
risks were evaluated Site-wide and in adjacent areas, so no exposure area figure is
provided. Changes to the CSMs include:
• Exposure to coal combustion residual (CCR) constituents by Site workers is
considered incomplete, because Duke Energy maintains strict health and safety
requirements and training. The use of personal protective equipment (e.g., boots,
gloves, safety glasses) and other safety behaviors exhibited by Site workers limits
exposure to CCR constituents. Following conservative risk assessment practices,
the initial risk assessment report considered CCR constituent exposure pathways
for Site workers to be potentially complete. Further information has revealed
that on-Site worker exposure pathways are incomplete, and this risk assessment
update has been revised to reflect this change.
• The number of ecological exposure areas was reduced from four to three, as
depicted in Figure 3. Other ecological exposure areas evaluated in the 2016 risk
assessment were eliminated because updated modeling and data collection
demonstrate that they are not influenced by groundwater migration from the ash
basins.
• Surface water sampling and sediment sampling of the Broad River allow for
direct assessment, rather than using AOW data as a surrogate.
Results from samples of surface water, sediment, and groundwater were compared
with human health and ecological screening values (Attachments 1 and 2) to identify
constituents of potential concern (COPCs) for further review. Exposure point
concentrations (EPCs) were calculated for COPCs (Attachments 3 and 4) to incorporate
into human health and ecological risk models. Results of risk estimates (Attachments 5
and 6) are summarized below.
Risk Assessment Summary Update November 2018
Cliffside Steam Station SynTerra

Page 3
2.0 SUMMARY OF RISK FINDINGS
2.1 Human Health
There is no exposure to residential receptors at or near CSS because no one lives on-Site
or near enough to the Site to be affected by groundwater migration from the ash basins.
Potential receptors off-Site are recreational users of the Broad River, including
swimmers, waders, boaters, and fishers. However, background concentrations of the
same elements also present similar risks to the same potential receptors. Those risks are
not associated with the ash basins.
• There is no material increase in cancer risks attributable to the ash basins
associated with the boater, swimmer, and wader exposure scenarios.
o There is no material increase in cancer risks for the boater, swimmer, and
wader exposure scenarios attributable to the ash basins. Incorporating
arsenic concentrations in sediment samples and hexavalent chromium
concentrations in surface water samples collected since the 2018 CSA
update produced modeled potential carcinogenic risks under the boater,
swimmer, and wader scenarios. However, these modeled risks are not
materially greater than the background level of risk. Sediment samples
collected upstream of the site contained as much as 1.5 mg/kg arsenic,
compared to the risk assessment EPC of 1.85 mg/kg calculated from
sampling data. The hexavalent chromium EPC calculated based on
sampling data for use in the risk assessment was 0.3 µg/L, compared to
the upstream concentration of 0.09 µg/L. Although the EPCs are slightly
greater than the background concentrations, they do not produce a
materially greater amount of risk in the model. There is, therefore, no
material increase in cancer risks attributable to the ash basins.
o No evidence of non-carcinogenic risks for the recreational swimmer,
wader, or boater exposure scenarios was identified.
• There is no material increase in cancer risks attributable to the ash basins
associated with the fisher exposure scenario.
o There is no material increase in cancer risks for the fisher exposure
scenario attributable to the ash basins. Hexavalent chromium
concentrations in surface water produced modeled results of potential
carcinogenic risks under the recreational and subsistence fishing exposure
scenarios. However, substituting hexavalent chromium concentrations
detected in surface water samples upstream of the Site also resulted in
Risk Assessment Summary Update November 2018
Cliffside Steam Station SynTerra

Page 4
modeled risks under the exposure assumptions. There is, therefore, no
material increase in cancer risks attributable to the ash basins. Moreover,
risk estimates from fish consumption are based on CCR constituent
concentrations in fish tissue modeled from concentrations in surface
water. Thus, the modeled concentration of hexavalent chromium in fish
tissue is likely overestimated. 1
o No evidence of non-carcinogenic risks was identified for the recreational
fisher potentially exposed to the Broad River by dermal contact or fish
consumption.
o Potential non-carcinogenic risks from consumption of fish containing
cobalt (modeled from surface water concentrations) were modeled for the
subsistence fisher on the Broad River. Subsistence fishing, defined by
USEPA (2000) as ingestion of 170 grams (0.375 pounds) of fish per day,
has not been identified on the Broad River.2 But even if there were
subsistence fishers using the water body, there would be no material
increase in risks to them posed by the ash basin. The cobalt EPC used in
the risk assessment was 1.0 µg/L, compared to the upstream concentration
of 0.2 µg/L. When substituted into the risk assessment model, the
upstream cobalt concentration also resulted in modeled potential risks.
There is no material increase in risks attributable to the ash basins. In any
event, the fisher exposure scenarios overestimate risks based on exposure
model assumptions of bioconcentration and fish consumption rates.
There is not likely to be any material increase in non-carcinogenic risks for
the subsistence fisher scenario.
• The updated risk assessment found no evidence of risks associated with
exposure to groundwater by Site workers. Trespasser exposure to AOWs was

1 For conservative estimation of hexavalent chromium concentrations in fish tissue, the recreational and
subsistence fisher exposure models used in this risk assessment assume a hexavalent chromium
bioconcentration factor (BCF) of 200 (NRCP, 1996). Bioconcentration is the process by which a chemical is
absorbed by an organism from the ambient environment through its respiratory and dermal surfaces
(Arnot and Gobus, 2006). The degree to which bioconcentration occurs is expressed as the BCF.
Published BCFs for hexavalent chromium in fish can be as low as one, suggesting that potential
bioconcentration in fish is low (USEPA, 1980; 1984; Fishbein, 1981; ATSDR, 2012). The conservative BCF
of 200 used here likely overestimates the hexavalent chromium concentration in fish tissue.
2 To put the fish ingestion rate into context, a 170 gram per day fish meal is approximately equal to six
ounces or approximately five fish sticks per meal (see http://gortons.com/product/original-batter-
tenders); it is assumed that the subsistence fisher catches this amount of fish in the local water body and
has such a fish meal once per day, every day for years.
Risk Assessment Summary Update November 2018
Cliffside Steam Station SynTerra

Page 5
not evaluated because AOWs are addressed in the SOC. There is, therefore, no
material increase in risks associated with onsite exposure scenarios.
In summary, there is no material increase in risks to human health attributable to the
Cliffside ash basins.
2.2 Ecological
There is no evidence of ecological risks associated with the Broad River, Suck Creek,
and adjacent wooded areas (Exposure Areas 1, 2, and 4).
• In practice, ecological risks are quantified by comparing an average daily dose
(ADD) of a constituent to a toxicity reference value (TRV) for a given wildlife
receptor. The ratio of the ADD and TRV is the hazard quotient (HQ), where an
HQ less than unity (1) indicates no evidence of risks. TRVs are generally no-
observed-adverse-effects-levels (NOAEL) or a lowest-observed-adverse-effects-
levels (LOAEL) from toxicity studies published in scientific literature.
• No HQs based on LOAELs exceeded unity for the wildlife receptors (mallard
duck, great blue heron, muskrat) exposed to surface water and sediments.
• One HQ based on a NOAEL of aluminum was 1.59 for the muskrat. The
modeled risk related to aluminum is negligible. Moreover, the model likely
overestimates any real risk. Aluminum occurs naturally in soil, sediment and
surface water in this area. Per the U.S. Geological Survey (USGS), aluminum is
the third most abundant element following oxygen and silicon in the Earth's
crust (USGS, 2018).
In summary, the CSS ash basins do not cause any material increase in risks to ecological
receptors.
Risk Assessment Summary Update November 2018
Cliffside Steam Station SynTerra

Page 6
3.0 REFERENCES
Agency for Toxic Substances and Disease Registry (ATSDR). (2012). Toxicological
Profile for Chromium. Atlanta, GA: U.S. Department of Health and Human
Services, Public Health Service.
Arnot, J.A. and F.A.P.C. Gobus. (2006). A review of bioconcentration factor (BCF) and
bioaccumulation factor (BAF) assessments for organic chemicals in aquatic
organisms. Environmental Reviews 14: 257–297.
Fishbein, L. (1981). Sources, transport and alterations of metal compounds: an
overview. I. Arsenic, beryllium, cadmium, chromium, and nickel.
Environmental Health Perspectives 40: 43-64.
National Council on Radiation Protection and Measurements (NCRP). (1996).
Screening Models for Releases of Radionuclides to Atmosphere, Surface Water
and Ground. NCR Report No. 123. Cited in:
https://www.tn.gov/assets/entities/health/attachments/Screen.pdf
SynTerra. (2018). 2018 Comprehensive Site Assessment Update, January 31, 2018.
United States Environmental Protection Agency. (1980). Ambient water quality criteria
for chromium. Washington, D.C. EPA 440/5-80-035.
United States Environmental Protection Agency. (1984). Health assessment document
for chromium. Research Triangle Park, NC. EPA 600/8-83-014F.HDR. (2016).
Corrective Action Plan Part 2 – Cliffside Steam Station Ash Basin, February 11,
2016.
United States Environmental Protection Agency. (1989). Risk Assessment Guidance for
Superfund: Volume 1 - Human Health Evaluation Manual (Part A). Office of
Emergency and Remedial Response, Washington, D.C. EPA/540/1-89/002.
United States Environmental Protection Agency. (1991). Risk Assessment Guidance for
Superfund: Volume 1 - Human Health Evaluation Manual (Part B, Development
of Risk-based Preliminary Remediation Goals). Office of Emergency and
Remedial Response, Washington, D.C. EPA/540/R-92/003.
United States Environmental Protection Agency. (1998). Guidelines for Ecological Risk
Assessment. Washington, D.C. EPA/630/R-95/002F.
United States Environmental Protection Agency. (2000). Guidance for Assessing
Chemical Contaminant Data for Use in Fish Advisories. Volume 1, Fish
Risk Assessment Summary Update November 2018
Cliffside Steam Station SynTerra

Page 7
Sampling and Analysis, Third Edition. Office of Science and Technology, Office
of Water, Washington, D.C. EPA 823-B-00-007.
United States Geological Survey. (2018, October 29). Aluminum Statistics and
Information. Retrieved from
https://minerals.usgs.gov/minerals/pubs/commodity/aluminum/
Risk Assessment Summary Update November 2018
Cliffside Steam Station SynTerra

FIGURES
š (b)
Coal Ash
Basins Post Excavation
Soil
AOWs (c)
Groundwater
Dust Outdoor Air
Soil Remaining
Post-Excavation
(d)
Surface Water
(Off-site)
(e)
Surface Water
(On -site)
Sediment
(Off-site)
(e)
Fish Tissue
(f)
Groundwater
Migration to
Surface Water
and Sediment
Inhalation
Incidental
Ingestion
Dermal Contact
Drinking Water
Use
Incidental
Ingestion
Incidental
Ingestion
Dermal Contact
Incidental
Ingestion
Dermal Contact
Ingestion
Drinking Water
Use (b)
Dermal Contact
Incidental
Ingestion
Potential
Exposure
Route
Current/
Future Off-Site
Resident
Adult/Child
Current/
Future On-Site
Recreational
Trespasser
Current/
Future Off-Site
Recreational
Swimmer
Current/
Future Off-Site
Recreational
Wader
Current/
Future Off-Site
Recreational
Boater
Current/
Future Off-Site
Recreational /
Subsistence
Fisher
Current/
Future On-site
Commercial/
Industrial
Worker
Current/
Future On-Site
Construction
Worker
š š š š
šš š š š
š š š š š
šš š š š
š š š
š š š š š (b)š š
š š š š š (b)š š
š š š š š š š
š š š š ˜š š
š š š
š ˜˜š š
š š š š
Primary
Sources
Primary
Release
Mechanisms
Secondary
Sources
Secondary
Release
Mechanisms
Potential
Exposure
Media
Human Receptors
˜
š
(a)
Potentially complete exposure pathway based on results of 2018 risk assessment
update.
Pathway evaluated and found incomplete /insignificant .
Incidental surface water ingestion assumed only to occur for receptors for the
swimming and wading scenarios.
Infiltration/
Leaching
Runoff/Flooding
Infiltration/
Leaching
Dermal Contact š š š ˜˜
AOW Water
(On -site)Dermal Contact š š š š š
AOW Soil
(On -site)Dermal Contact
Sediment
(On -site)
Incidental
Ingestion
Dermal Contact
š š š š š
š š
š ˜(a)š š
˜˜
š
š
š
š
š š š š š š
š š š š š š š
š š š š š š
š
š
˜(a)
š
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š š
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NOTES
š
š
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˜˜
š
š
š
š
š
š
š
š
š
š š š
š
š
š
FIGURE 1
HUMAN HEALTH RISK ASSESSMENT
CONCEPTUAL SITE MODEL
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA
š š
š š
Concentration of COPCs in fish tissue modeled from surface water concentration .
(e)
(f)
Broad River.
Pathway incomplete as long as ash remains in place ; re-evaluation upon
excavation (if conducted ) may be warranted.
(d)
Areas of Wetness (AOWs) are addressed in the Special Order by Consent
(SOC) and not evaluated in the risk assessment update at this time.
Groundwater exposure evaluated in the risk assessment update, although an
incomplete exposure pathway for construction worker .
(c)
(b)
š š š š
š
š
š
š š š š
š
š
˜
š
š
š
š
š
š
š
š
š
š
MammalMammal
š š
š
˜˜
Red Fox
(Carnivore)
š
š
š
š
š
š
River Otter
(Piscivore )
š
š
š
š
š
š
š
Robin
(Omnivore)
š
š
š
š
š
š
š
š
š
š
Avian
š
TERRESTRIAL (d)
Inhalation
Plant/Incidental
Ingestion
Direct Contact
Ingestion
Ingestion
Direct Contact
Plant/Incidental
Ingestion
Direct Contact
Ingestion
Direct Contact
Ingestion
Potential
Exposure Route Fish
š
š
š
Primary Sources Primary Release
Mechanisms
Secondary
Sources
Secondary Release
Mechanisms
Potential
Exposure Media
AQUATIC
Direct Contact l(e)
Ingestion š
Plant/Incidental
Ingestion
Plant/Incidental
Ingestion
Direct Contact
š
š
š
š
š
š
š
š
š
Active Coal
Ash Basins
Post Excavation
Soil
AOWs (a)
Groundwater
Dust Outdoor Air
Soil Remaining
Post-Excavation
(b)
Surface Water
(Off-site )
Surface Water
(On-site)
Sediment
(Off-site)
Fish Tissue
(c)
Groundwater
Migration to
Surface Water
and Sediment
Infiltration/
Leaching
Runoff/Flooding
Infiltration/
Leaching
AOW Water
(On-site)
AOW Soil
(On-site)
Sediment
(On-site)
˜
š
Potentially complete exposure pathway based on results of 2018 risk
assessment update.
Pathway evaluated and found incomplete/insignificant.
Benthic
Invertebrates Mallard
(Omnivore)
Great Blue
Heron
(Piscivore)
Muskrat
(Herbivore)
š š š
š š
š š š š
š š š š
š š š
š š š
l(e)
l(e)
š š
š
š š š
š š
š š š
š
š š š š
š š š š
š
š š š
š š š
š
š
š
š
š
Avian
Meadow Vole
(Herbivore)
š
š
š š
˜˜˜š š
š
š
š
š
š
š
š
š
Red-Tailed
Hawk
(Carnivore)
š
š
š
˜
š
š
š
š
š
š
š
š
š
š Areas of Wetness (AOWs) are addressed in the Special Order by Consent
(SOC) and not evaluated in the risk assessment update at this time.
Pathway incomplete as long as ash remains in place ; re-evaluation
upon excavation (if conducted) may be warranted.
š š
˜˜š š
š
š
NOTES
CSM reflects exposure pathways evaluated quantitatively in the risk assessment .
š š š š š š š
š š š
š š
š š
š
š
FIGURE 2
ECOLOGICAL RISK ASSESSMENT
CONCEPTUAL SITE MODEL
CLIFFSIDE STEAM STATION
MOORESBORO, NORTH CAROLINA
š š š š š š š š
š š
š
š
š
Concentration of COPCs in fish tissue modeled from surface water
concentration.
Exposure to terrestrial receptors was not evaluated because AOWs
are addressed in the SOC.
(c)
(d)
(a)
Based on screening against aquatic criteria.(e)
(b)
")
")
")
")
")
")
")
")
")
")")
")")
")
")
")
")")
")
")
")
")
")
")
")
")")
")")")
")
")
EXPOSUREAREA 4
EXPOSUREAREA 1
EXPOSUREAREA 2
EXPOSUREAREA 3(SEE NOT E 3)
UNIT 5INACTIVEASH BASIN
C
LIF
F
SI
D
E

H
I
G
H
WA
Y
FORM ERUNITS 1-4ASH BASIN
ACTIVEASH BASIN
SPOILAREA
ASHSTORAGE
SC _2_UP
CLFSTR-53
SC_2_DN
S-8
S W -1
SW -2
S W -3
SW -4
SW -5
S W-7
S W -8
SW -9 S W -BRAB-1 SW -BRAB-2
SW -BRAB-3
S W -BRBG
S W-BRU14-1
S W -BRU14-2
SW -BRU14-3
S W-BRU5-1
SW -SBRBG
S W-S C-1
S W-S C-2
SW -SC-3
SW -SC-4
SW-S C-5
S W -S C-6
SW -SC-7SW-W CU5-1
S W -10A
SW -10B
S W -10C
FIGURE 3HUMAN HEA LT H ANDECOLOGICAL E XPOSURE AREASCLIFFSIDE STEAM ST AT IONDUKE E NERG Y CAROLINAS, LLCMOORESBORO, NO RT H CAROLINADRAWN BY: A. FEIGLPROJECT MANAGER: S. SPINNERCHECKED BY: T. GRANT
DATE: 10/31/2018
148 RIVER STREET, SUITE 220GREENVILLE, SOUTH CAROLINA 29601PHONE [phone]www.synterracorp.com
P:\Duke Energy Progress.1026\00 GIS B ASE DATA\Cli ffside\M apdocs\MISC\Risk Assessment\Fig03_CliffsideExposureAreas.mxd
400 0 400 800200
GRAPHIC SCALE IN FEET
BROAD RIVER
CCPLANDFILL
NOTES:
1. GENERA LIZED AREAL E XTENT OF MIGRATION REPRESENTED BY NCAC 02LEXCEEDANCES OF MULTIPLE CONS TIT UENTS IN MULTIPLE FLOW ZONES.
2. FOUR EXPOS URE AREAS WERE DEVELOPED TO EVALUATE ECOLOGICALEXPOSURE TO SURFACE WATER AND SEDIMENT. THE EXPOSURE AREAS CONSIDERECOLOGICAL HABITATS, NEARBY WATER BODIES, AND WET AREAS.
3. ECOLOGICAL EXPOSURE ARE A 3 IS CONSIDERED A BACKGROUND LOCATION ANDWAS NOT EVALUATED.
4. PROPE RT Y BOUNDARY PROVIDED BY DUKE ENERGY CAROLINAS.
5. AERIAL PHOTOGRAPHY OBTAINE D FROM GOOGLE EARTH PRO ON SEPTEMBER 26,2017 . AERIAL WAS C OLLECTED ON APRIL 1, 2017.
6. DRAWING HAS BEEN SET WITH A PROJ ECTION OF NORTH CAROLINA STATE PLANECOORDINATE SY STEM FIP S 3 200 (NAD83/2011).
7. AT TH E TIME OF COMP LETION OF RE CEPTOR S URVEYS THE UNIT 5 INACTIVE ASHBASIN AN D UNITS 1-4 INA CTIVE ASH B ASIN WERE ASSUMED TO HAVE COMPLIANCEBOUNDARIES.
LEGEND
EXPOSURE AREA 1
EXPOSURE AREA 2EXPOSURE AREA 3
EXPOSURE AREA 4
AR EA OF CONCENTRATION IN GROUNDWATERABOVE NC2L (SEE NOTES)
ASH BASIN WASTE BOUNDARY
ASH BASIN C OMPLIANCE BOUNDARY
LANDFILL / ASH STORAGE AREA BOUNDARY
DUKE ENERGY CAROLINAS CLIFFSIDE PLANTSITE BOUNDARY
<STREAM (AMEC N RTR 2015)
WETLAND (AMEC NRTR 2015)
LANDFILL COMPLIANCE BOUNDARY
")SU RFACE WATER LOCATION
Risk Assessment Summary Update November 2018
Cliffside Steam Station SynTerra

ATTACHMENTS
TABLE 1-1
HUMAN HEALTH SCREENING - GROUNDWATER
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Min.Max.
Aluminum 7429-90-5 1,539 1,080 5 128,000 128,000 NA NA 3,500 50 to 200 (i)4,000 3,500 Y
Antimony 7440-36-0 2,003 629 0.1 94.9 94.9 1 NA 1 6 1.56 (m)1 Y
Arsenic 7440-38-2 2,075 1,708 0.04 4,680 4,680 10 NA 10 10 0.052 (h,jj)10 Y
Barium 7440-39-3 2,086 2,036 2.5 5,090 5,090 700 NA 700 2,000 760 700 Y
Beryllium 7440-41-7 1,942 1,161 0.01 98.6 98.6 NA 4 4 4 5 4 Y
Boron 7440-42-8 2,089 1,371 25 2,750 2,750 700 NA 700 NA 800 700 Y
Cadmium 7440-43-9 2,075 619 0.026 94.1 94.1 2 NA 2 5 1.84 2 Y
Chromium (Total)7440-47-3 2,063 1,765 0.092 838 838 10 NA 10 100 4,400 (n)10 Y
Chromium (VI)18540-29-9 1,267 799 0.0083 25.2 25.2 NA NA 0.07 NA 0.035 (jj)0.07 Y
Cobalt 7440-48-4 1,942 1,803 0.01 895 895 NA 1 1 NA 1.2 1 Y
Copper 7440-50-8 1,661 1,200 0.11 316 316 1,000 NA 1,000 1,300 (k)160 1,000 N
Lead 7439-92-1 2,075 1,057 0.028 84.3 84.3 15 NA 15 15 (l)15 (jj)15 Y
Lithium 7439-93-2 693 673 0.17 467 467 NA NA NA NA 8 8 Y
Manganese 7439-96-5 1,684 1,612 2.5 37,000 37,000 50 NA 200 50 (i)86 50 Y
Mercury 7439-97-6 2,081 159 0.05 13 13 1 NA 1 2 1.14 (o)1 Y
Molybdenum 7439-98-7 1,947 1,103 0.081 337 337 NA NA 18 NA 20 18 Y
Nickel 7440-02-0 1,661 1,391 0.14 380 380 100 NA 100 NA 78 (p)100 Y
Selenium 7782-49-2 2,075 821 0.17 117 117 20 NA 20 50 20 20 Y
Strontium 7440-24-6 1,539 1,534 3.4 40,400 40,400 NA NA 2,100 NA 2,400 2,100 Y
Thallium 7440-28-0 2,001 1,144 0.015 5.6 5.6 0.2 NA 0.2 2 0.04 (q)0.2 Y
Vanadium 7440-62-2 1,523 1,094 0.058 207 207 NA NA 0.3 NA 17.2 0.3 Y
Zinc 7440-66-6 1,672 1,107 2.447 870 870 1 NA 1 5,000 (i)1,200 1 Y
Notes:
AWQC - Ambient Water Quality Criteria DENR - Department of Environment and Natural Resources NC - North Carolina su - Standard units
CAMA - Coal Ash Management Act DHHS - Department of Health and Human Services NCAC - North Carolina Administrative Code µg/L - micrograms/liter
North Carolina Session Law 2014-122, ESV - Ecological Screening Value ORNL - Oak Ridge National Laboratory USEPA - United States Environmental Protection Agency
HH - Human Health PSRG - Preliminary Soil Remediation Goal WS - Water Supply
/Senate/PDF/S729v7.pdf HI - Hazard Index Q - Qualifier < - Concentration not detected at or above the reporting limit
CAS - Chemical Abstracts Service IMAC - Interim Maximum Allowable Concentration RSL - Regional Screening Level j - Indicates concentration reported below Practical Quantitation Limit
CCC - Criterion Continuous Concentration MCL - Maximum Contaminant Level RSV - Refinement Screening Value (PQL) but above Method Detection Limit (MDL) and therefore concentration is estimated
CMC - Criterion Maximum Concentration mg/kg - milligrams/kilogram SMCL - Secondary Maximum Contaminant Level
COPC - Constituent of Potential Concern NA - Not Available SSL - Soil Screening Level
Concentration
Used for
Screening
(µg/L)
15A NCAC 02L
.0202 Standard
(e)
(µg/L)
15A NCAC
02L .0202
IMAC (e)
(µg/L)
DHHS
Screening
Level (d)
(µg/L)
Federal MCL/
SMCL (c)
(µg/L)
Tap Water RSL
HI = 0.2 (a)
(µg/L)
Screening
Value Used
(µg/L)
Number of
Samples
Frequency of
Detection
Range of Detection
(µg/L)COPC?Analyte CAS
http://www.ncleg.net/Sessions/2013/Bills
* Data evaluated includes data from 2015 to August 2018 Prepared by: HEG Checked by: HES
Page 1 of 2
TABLE 1-1
HUMAN HEALTH SCREENING - GROUNDWATER
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
(a) - USEPA Regional Screening Levels (May 2018). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed October 2018.
https://www.epa.gov/risk/regional-screening-levels-rsls-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed October 2018.
https://www.epa.gov/wqc/national-recommended-water-quality-criteria-human-health-criteria-table
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2018 Edition of the Drinking Water Standards and Health Advisories. March 2018. Accessed October 2018.
https://www.epa.gov/sites/production/files/2018-03/documents/dwtable2018.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental
Epidemiology Branch. http://portal.ncdenr.org/c/document_library/get_file?p_l_id=1169848&folderId=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Groundwater Standards & IMACs. http://portal.ncdenr.org/c/document_library/get_file?uuid=1aa3fa13-2c0f-45b7-ae96-5427fb1d25b4&groupId=38364
Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http://reports.oah.state.nc.us/ncac/title%2015a%20-%20environmental%20quality/chapter%2002%20-%20environmental%20management/subchapter%20b/subchapter%20b%20rules.pdf
WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption of fish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stingent of all applicable standards.
(g) - USEPA Region 4. 2018. Region 4 Ecological Risk Assessment Supplemental Guidance. March 2018 Update.
https://www.epa.gov/sites/production/files/2018-03/documents/era_regional_supplemental_guidance_report-march-2018_update.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals
(j) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(l) - Lead Treatment Technology Action Level is 0.015 mg/L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium.
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and
CMC1 and CMC2 are 185.9 µ/gL and 12.82 µ/gL, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 µ/gL.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http://www.lanl.gov/community-environment/environmental-stewardship/protection/eco-risk-assessment.php
(y) - Long, Edward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program.
NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bernacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for
Florida Inland Waters. Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario.
(bb) - Los Alamos National Laboratory ECORISK Database. September 2017. http://www.lanl.gov/environment/protection/eco-risk-assessment.php (µg/kg dw)
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http://www.epa.gov/gliclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/TM-96/R2.
http://www.esd.ornl.gov/programs/ecorisk/documents/tm96r2.pdf
(ee) - USEPA. Interim Ecological Soil Screening Level Documents. Accessed October 2018. http://www2.epa.gov/chemical-research/interim-ecological-soil-screening-level-documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter II, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-126/R2. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm126r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-85/R3. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI = 0.2. September 2015. http://portal.ncdenr.org/c/document_library/get_file?uuid=0f601ffa-574d-4479-bbb4-253af0665bf5&groupId=38361
as part of a risk assessment based on potential toxic effects, therefore; pH was not investigated further as a category 1 COPC. Water quality relative to pH will be addressed as a component of water quality monitoring programs for the site.
(jj) - Hazard Index = 0.1
(ii) - As part of the water quality evaluation conducted under the CSA, pH was measured and is reported as a metric data set. The pH comparison criteria are included as ranges as opposed to single screening values. pH is not typically included
Page 2 of 2
TABLE 1-2
HUMAN HEALTH SCREENING - SEDIMENT
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Min.Max.
Aluminum 7429-90-5 15 15 2,200 40,000 40,000 15,000 15,400 100,000 220,000 15,000 100,000 Y N
Antimony 7440-36-0 15 0 ND ND ND 6.2 (m)6.2 (m)94 (m)94 (m)6.2 94 N N
Arsenic 7440-38-2 15 13 0.47 3.9 3.9 0.68 (h)0.68 (h, jj)3 (h)3 (h, jj)0.68 3 Y Y
Barium 7440-39-3 15 15 7.7 200 200 3,000 3,000 44,000 44,000 3,000 44,000 N N
Beryllium 7440-41-7 15 15 0.098 1.5 1.5 32 32 460 460 32 460 N N
Boron 7440-42-8 15 0 ND ND ND 3,200 3,200 46,000 46,000 3,200 46,000 N N
Cadmium 7440-43-9 15 8 0.05 0.39 0.39 14 14.2 200 196 14 200 N N
Chromium (Total)7440-47-3 15 15 8.2 44 44 24,000 (n)24,000 (n)100,000 (n)360,000 (n)24,000 100,000 N N
Chromium (III)16065-83-1 2 2 18.5 37.4 37.4 24,000 24,000 100,000 360,000 24,000 100,000 N N
Cobalt 7440-48-4 15 13 1.1 12 12 4.6 4.6 70 70 4.6 70 Y N
Copper 7440-50-8 15 15 0.96 21 21 620 620 9,400 9,400 620 9,400 N N
Lead 7439-92-1 15 14 2 16 16 400 400 (jj)800 800 (jj)400 800 N N
Manganese 7439-96-5 15 15 22 780 780 360 360 5,200 5,200 360 5,200 Y N
Mercury 7439-97-6 15 1 0.0081 0.0081 0.0081 4.6 (o)4.6 (o)3.1 (o)70 (o)4.6 3.1 N N
Molybdenum 7439-98-7 15 0 ND ND ND 78 78 1,200 1,160 78 1,200 N N
Nickel 7440-02-0 15 15 1.5 20 20 300 (p)300 (p)4,400 (p)4,400 (p)300 4,400 N N
Selenium 7782-49-2 15 0 ND ND ND 78 78 1,200 1,160 78 1,200 N N
Strontium 7440-24-6 15 14 0.76 16 16 9,400 9,400 100,000 140,000 9,400 100,000 N N
Thallium 7440-28-0 15 13 0.035 0.5 0.5 0.16 (q)0.156 (q)2.4 (q)2.4 (q)0.16 2.4 Y N
Vanadium 7440-62-2 15 15 5.6 66 66 78 78 1,160 1,160 78 1,160 N N
Zinc 7440-66-6 15 15 5.2 90 90 4,600 4,600 70,000 70,000 4,600 70,000 N N
Notes:
AWQC - Ambient Water Quality Criteria DENR - Department of Environment and Natural Resources NC - North Carolina su - Standard units
CAMA - Coal Ash Management Act DHHS - Department of Health and Human Services NCAC - North Carolina Administrative Code µg/L - micrograms/liter
North Carolina Session Law 2014-122, ESV - Ecological Screening Value ORNL - Oak Ridge National Laboratory USEPA - United States Environmental Protection Agency
HH - Human Health PSRG - Preliminary Soil Remediation Goal WS - Water Supply
/Senate/PDF/S729v7.pdf HI - Hazard Index Q - Qualifier < - Concentration not detected at or above the reporting limit
CAS - Chemical Abstracts Service IMAC - Interim Maximum Allowable Concentration RSL - Regional Screening Level j - Indicates concentration reported below Practical Quantitation Limit
CCC - Criterion Continuous Concentration MCL - Maximum Contaminant Level RSV - Refinement Screening Value (PQL) but above Method Detection Limit (MDL) and therefore concentration is estimated
CMC - Criterion Maximum Concentration mg/kg - milligrams/kilogram SMCL - Secondary Maximum Contaminant Level
COPC - Constituent of Potential Concern NA - Not Available SSL - Soil Screening Level
Analyte CAS
Number
of
Samples
Frequency
of
Detection
Concentration
Used for
Screening
(mg/kg)
Range of Detection
(mg/kg)
NC PSRG
Residential Health
Screening Level
(hh)
(mg/kg)
Residential Soil
RSL (a)
HI = 0.2
(mg/kg)
NC PSRG
Industrial Health
Screening Level
(hh)
(mg/kg)
Industrial Soil
RSL (a)
HI = 0.2
(mg/kg)
Residential
Screening
Value Used
(mg/kg)
Industrial
Screening
Value Used
(mg/kg)
http://www.ncleg.net/Sessions/2013/Bills
Industrial
COPC?
Residential
COPC?
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted Prepared by: HEG Checked by: HES
Page 1 of 2
TABLE 1-2
HUMAN HEALTH SCREENING - SEDIMENT
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
(a) - USEPA Regional Screening Levels (May 2018). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed October 2018.
https://www.epa.gov/risk/regional-screening-levels-rsls-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed October 2018.
https://www.epa.gov/wqc/national-recommended-water-quality-criteria-human-health-criteria-table
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2018 Edition of the Drinking Water Standards and Health Advisories. March 2018. Accessed October 2018.
https://www.epa.gov/sites/production/files/2018-03/documents/dwtable2018.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental
Epidemiology Branch. http://portal.ncdenr.org/c/document_library/get_file?p_l_id=1169848&folderId=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Groundwater Standards & IMACs. http://portal.ncdenr.org/c/document_library/get_file?uuid=1aa3fa13-2c0f-45b7-ae96-5427fb1d25b4&groupId=38364
Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http://reports.oah.state.nc.us/ncac/title%2015a%20-%20environmental%20quality/chapter%2002%20-%20environmental%20management/subchapter%20b/subchapter%20b%20rules.pdf
WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption of fish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stingent of all applicable standards.
(g) - USEPA Region 4. 2018. Region 4 Ecological Risk Assessment Supplemental Guidance. March 2018 Update.
https://www.epa.gov/sites/production/files/2018-03/documents/era_regional_supplemental_guidance_report-march-2018_update.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals
(j) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(l) - Lead Treatment Technology Action Level is 0.015 mg/L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium.
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and
CMC1 and CMC2 are 185.9 µg/L and 12.82 µg/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 µg/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http://www.lanl.gov/community-environment/environmental-stewardship/protection/eco-risk-assessment.php
(y) - Long, Edward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program.
NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bernacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for
Florida Inland Waters. Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario.
(bb) - Los Alamos National Laboratory ECORISK Database. September 2017. http://www.lanl.gov/environment/protection/eco-risk-assessment.php (µg/kg dw)
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http://www.epa.gov/gliclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/TM-96/R2.
http://www.esd.ornl.gov/programs/ecorisk/documents/tm96r2.pdf
(ee) - USEPA. Interim Ecological Soil Screening Level Documents. Accessed October 2018. http://www2.epa.gov/chemical-research/interim-ecological-soil-screening-level-documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter II, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-126/R2. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm126r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-85/R3. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI = 0.2. September 2015. http://portal.ncdenr.org/c/document_library/get_file?uuid=0f601ffa-574d-4479-bbb4-253af0665bf5&groupId=38361
as part of a risk assessment based on potential toxic effects, therefore; pH was not investigated further as a category 1 COPC. Water quality relative to pH will be addressed as a component of water quality monitoring programs for the site.
(jj) - Hazard Index = 0.1
(ii) - As part of the water quality evaluation conducted under the CSA, pH was measured and is reported as a metric data set. The pH comparison criteria are included as ranges as opposed to single screening values. pH is not typically included
Page 2 of 2
TABLE 1-3
HUMAN HEALTH SCREENING - SURFACE WATER
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Min.Max.
Aluminum 7429-90-5 72 70 72.9 1,320 1,320 NA NA NA NA NA NA 50 to 200 (i)4,000 50 Y
Antimony 7440-36-0 72 1 0.17 0.17 0.17 1 NA NA NA 5.6 640 6 1.56 (m)1 N
Arsenic 7440-38-2 73 71 0.12 4.3 4.3 10 NA 10 10 0.018 (h)0.14 (h)10 0.052 (h, jj)10 N
Barium 7440-39-3 73 73 13.1 60.6 60.6 700 NA 1,000 NA 1,000 NA 2,000 760 700 N
Beryllium 7440-41-7 72 55 0.01 0.067 0.067 NA 4 NA NA NA NA 4 5 4 N
Boron 7440-42-8 73 32 25.5 179 179 700 NA NA NA NA NA NA 800 700 N
Cadmium 7440-43-9 73 2 0.07 0.083 0.083 2 NA NA NA NA NA 5 1.84 2 N
Chromium (Total)7440-47-3 73 70 0.16 2.4 2.4 10 NA NA NA NA NA 100 4,400 (n)10 N
Chromium (VI)18540-29-9 67 56 0.018 1 1 NA NA NA NA NA NA NA 0.035 (jj)0.035 Y
Cobalt 7440-48-4 72 72 0.12 3.4 3.4 NA 1 NA NA NA NA NA 1.2 1 Y
Copper 7440-50-8 73 59 0.11 1.9 1.9 1,000 NA NA NA 1,300 NA 1,300 (k)160 1,000 N
Lead 7439-92-1 73 73 0.095 0.95 0.95 15 NA NA NA NA NA 15 (l)15 (jj)15 N
Lithium 7439-93-2 4 4 0.62 0.67 0.67 NA NA NA NA NA NA NA 8 8 N
Manganese 7439-96-5 72 72 26.8 1,040 1,040 50 NA 200 NA 50 100 50 (i)86 50 Y
Mercury 7439-97-6 73 68 2.76E-04 0.00226 0.00226 1 NA NA NA NA NA 2 1.14 (o)1 N
Molybdenum 7439-98-7 72 7 0.11 0.71 0.71 NA NA NA NA NA NA NA 20 20 N
Nickel 7440-02-0 73 41 0.32 2.4 2.4 100 NA 25 NA 610 4,600 NA 78 (p)100 N
Selenium 7782-49-2 73 4 0.21 0.41 0.41 20 NA NA NA 170 4,200 50 20 20 N
Strontium 7440-24-6 72 72 18 206 206 NA NA NA NA NA NA NA 2,400 2,400 N
Thallium 7440-28-0 74 26 0.016 0.069 0.069 0.2 NA NA NA 0.24 0.47 2 0.04 (q)0.2 N
Vanadium 7440-62-2 72 69 0.12 2.9 2.9 NA NA NA NA NA NA NA 17.2 17 N
Zinc 7440-66-6 73 28 2.5 22.9 22.9 1 NA NA NA 7,400 26,000 5,000 (i)1,200 1 Y
Notes:
AWQC - Ambient Water Quality Criteria DENR - Department of Environment and Natural Resources NA - Not Available SMCL - Secondary Maximum Contaminant Level
CAMA - Coal Ash Management Act DHHS - Department of Health and Human Services NC - North Carolina SSL - Soil Screening Level
North Carolina Session Law 2014-122, ESV - Ecological Screening Value NCAC - North Carolina Administrative Code su - Standard units
http://www.ncleg.net/Sessions/2013/Bills/Senate/PDF/S729v7.pdf HH - Human Health ORNL - Oak Ridge National Laboratory µg/L - micrograms/liter
CAS - Chemical Abstracts Service HI - Hazard Index PSRG - Preliminary Soil Remediation Goal USEPA - United States Environmental Protection Agency
CCC - Criterion Continuous Concentration IMAC - Interim Maximum Allowable Concentration Q - Qualifier WS - Water Supply
CMC - Criterion Maximum Concentration MCL - Maximum Contaminant Level RSL - Regional Screening Level < - Concentration not detected at or above the reporting limit
COPC - Constituent of Potential Concern mg/kg - milligrams/kilogram RSV - Refinement Screening Value
Screening
Value Used
(µg/L)
15A NCAC 02B
Water Supply
(WS) (f)
(µg/L)
COPC?Analyte CAS Number of
Samples
Frequency of
Detection
Prepared by: HEG Checked by: HES* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted.
15A NCAC 02B
Human Health
(HH) (f)
(µg/L)
USEPA AWQC
Consumption
of Water and
Organism (b)
(µg/L)
USEPA AWQC
Consumption
of Organism
Only (b)
(µg/L)
Range of Detection
(µg/L)
15A NCAC 02L
.0202 Standard
(e)
(µg/L)
15A NCAC 02L
.0202 IMAC
(e)
(µg/L)
Federal MCL/
SMCL (c)
(µg/L)
Tap Water RSL
HI = 0.2 (a)
(µg/L)
Concentration
Used for
Screening (µg/L)
Page 1 of 2
TABLE 1-3
HUMAN HEALTH SCREENING - SURFACE WATER
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
(a) - USEPA Regional Screening Levels (May 2018). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed October 2018.
https://www.epa.gov/risk/regional-screening-levels-rsls-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed October 2018.
https://www.epa.gov/wqc/national-recommended-water-quality-criteria-human-health-criteria-table
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2018 Edition of the Drinking Water Standards and Health Advisories. March 2018. Accessed October 2018.
https://www.epa.gov/sites/production/files/2018-03/documents/dwtable2018.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental
Epidemiology Branch. http://portal.ncdenr.org/c/document_library/get_file?p_l_id=1169848&folderId=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Groundwater Standards & IMACs. http://portal.ncdenr.org/c/document_library/get_file?uuid=1aa3fa13-2c0f-45b7-ae96-5427fb1d25b4&groupId=38364
Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http://reports.oah.state.nc.us/ncac/title%2015a%20-%20environmental%20quality/chapter%2002%20-%20environmental%20management/subchapter%20b/subchapter%20b%20rules.pdf
WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption of fish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stingent of all applicable standards.
(g) - USEPA Region 4. 2018. Region 4 Ecological Risk Assessment Supplemental Guidance. March 2018 Update.
https://www.epa.gov/sites/production/files/2018-03/documents/era_regional_supplemental_guidance_report-march-2018_update.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals
(j) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(l) - Lead Treatment Technology Action Level is 0.015 mg/L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium.
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and
CMC1 and CMC2 are 185.9 µg/L and 12.82 µg/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 µg/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http://www.lanl.gov/community-environment/environmental-stewardship/protection/eco-risk-assessment.php
(y) - Long, Edward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program.
NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bernacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for
Florida Inland Waters. Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario.
(bb) - Los Alamos National Laboratory ECORISK Database. September 2017. http://www.lanl.gov/environment/protection/eco-risk-assessment.php (µg/kg dw)
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http://www.epa.gov/gliclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/TM-96/R2.
http://www.esd.ornl.gov/programs/ecorisk/documents/tm96r2.pdf
(ee) - USEPA. Interim Ecological Soil Screening Level Documents. Accessed October 2018. http://www2.epa.gov/chemical-research/interim-ecological-soil-screening-level-documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter II, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-126/R2. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm126r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-85/R3. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI = 0.2. September 2015. http://portal.ncdenr.org/c/document_library/get_file?uuid=0f601ffa-574d-4479-bbb4-253af0665bf5&groupId=38361
as part of a risk assessment based on potential toxic effects, therefore; pH was not investigated further as a category 1 COPC. Water quality relative to pH will be addressed as a component of water quality monitoring programs for the site.
(jj) - Hazard Index = 0.1
(ii) - As part of the water quality evaluation conducted under the CSA, pH was measured and is reported as a metric data set. The pH comparison criteria are included as ranges as opposed to single screening values. pH is not typically included
Page 2 of 2
TABLE 2-1
ECOLOGICAL SCREENING - SEDIMENT - BROAD RIVER - EXPOSURE AREA 1
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Min.Max.ESV RSV
Aluminum 7429-90-5 7 7 5,100 37,000 37,000 25,000 (x)58,000 (x)25,000 Y
Antimony 7440-36-0 7 0 ND ND ND 2 (y)25 (y)2 N
Arsenic 7440-38-2 7 6 0.59 2.1 2.1 9.8 (z)33 (z)10 N
Barium 7440-39-3 7 7 23 200 200 20 (z)60 (z)20 Y
Beryllium 7440-41-7 7 7 0.22 1.5 1.5 NA NA NA N
Boron 7440-42-8 7 0 ND ND ND NA NA NA N
Cadmium 7440-43-9 7 5 0.13 0.39 0.39 1 (z)5 (z)1 N
Chromium (Total)7440-47-3 7 7 11 44 44 43.4 (z)111 (z)43 Y
Chromium (III)16065-83-1 1 1 18.5 18.5 18.5 NA NA NA N
Cobalt 7440-48-4 7 6 3.7 12 12 50 (aa)NA (aa)50 N
Copper 7440-50-8 7 7 1.9 21 21 31.6 (z)149 (z)31.6 N
Lead 7439-92-1 7 6 3.5 14 14 35.8 (z)128 (z)35.8 N
Manganese 7439-96-5 7 7 32 660 660 460 (bb)1,100 (bb)460 Y
Mercury 7439-97-6 7 1 0.0081 0.0081 0.0081 0.18 (z)1.1 (z)0.18 N
Molybdenum 7439-98-7 7 0 ND ND ND NA NA NA N
Nickel 7440-02-0 7 7 3.5 20 20 22.7 (z)48.6 (z)22.7 N
Selenium 7782-49-2 7 0 ND ND ND 0.8 (bb)1.2 (bb)0.8 N
Strontium 7440-24-6 7 7 1.9 16 16 NA NA NA N
Thallium 7440-28-0 7 6 0.089 0.5 0.5 NA NA NA N
Vanadium 7440-62-2 7 7 12 66 66 NA NA NA N
Zinc 7440-66-6 7 7 10 90 90 121 (z)459 (z)121 N
Notes:
AWQC - Ambient Water Quality Criteria DENR - Department of Environment and Natural Resources NC - North Carolina su - Standard units
CAMA - Coal Ash Management Act DHHS - Department of Health and Human Services NCAC - North Carolina Administrative Code µg/L - micrograms/liter
North Carolina Session Law 2014-122, ESV - Ecological Screening Value ORNL - Oak Ridge National Laboratory USEPA - United States Environmental Protection Agency
HH - Human Health PSRG - Preliminary Soil Remediation Goal WS - Water Supply
/Senate/PDF/S729v7.pdf HI - Hazard Index Q - Qualifier < - Concentration not detected at or above the reporting
CAS - Chemical Abstracts Service IMAC - Interim Maximum Allowable Concentration RSL - Regional Screening Level limit
CCC - Criterion Continuous Concentration MCL - Maximum Contaminant Level RSV - Refinement Screening Value j - Indicates concentration reported below Practical
CMC - Criterion Maximum Concentration mg/kg - milligrams/kilogram SMCL - Secondary Maximum Contaminant Level Quantitation Limit (PQL) but above Method Detection
COPC - Constituent of Potential Concern NA - Not Available SSL - Soil Screening Level Limit (MDL) and therefore concentration is estimated
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted Prepared by: TCP Checked by: HES
http://www.ncleg.net/Sessions/2013/Bills
Concentration
Used for
Screening
(mg/kg)
USEPA Region 4 Sediment
Screening Values (g)
(mg/kg)
Screening
Value Used
(mg/kg)
COPC?Analyte CAS Number of
Samples
Frequency
of
Detection
Range of
Detection
(mg/kg)
TABLE 2-1
ECOLOGICAL SCREENING - SEDIMENT - BROAD RIVER - EXPOSURE AREA 1
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
(a) - USEPA Regional Screening Levels (May 2018). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed October 2018.
https://www.epa.gov/risk/regional-screening-levels-rsls-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed October 2018.
https://www.epa.gov/wqc/national-recommended-water-quality-criteria-aquatic-life-criteria-table
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2018 Edition of the Drinking Water Standards and Health Advisories. March 2018. Accessed October 2018.
https://www.epa.gov/sites/production/files/2018-03/documents/dwtable2018.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental
Epidemiology Branch. http://portal.ncdenr.org/c/document_library/get_file?p_l_id=1169848&folderId=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Groundwater Standards & IMACs. http://portal.ncdenr.org/c/document_library/get_file?uuid=1aa3fa13-2c0f-45b7-ae96-5427fb1d25b4&groupId=38364
Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http://reports.oah.state.nc.us/ncac/title%2015a%20-%20environmental%20quality/chapter%2002%20-%20environmental%20management/subchapter%20b/subchapter%20b%20rules.pdf
WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption of fish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stingent of all applicable standards.
(g) - USEPA Region 4. 2018. Region 4 Ecological Risk Assessment Supplemental Guidance. March 2018 Update.
https://www.epa.gov/sites/production/files/2018-03/documents/era_regional_supplemental_guidance_report-march-2018_update.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals
(j) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(l) - Lead Treatment Technology Action Level is 0.015 mg/L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium.
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and
CMC1 and CMC2 are 185.9 µg/L and 12.82 µg/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 µg/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http://www.lanl.gov/community-environment/environmental-stewardship/protection/eco-risk-assessment.php
(y) - Long, Edward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program.
NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bernacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for
Florida Inland Waters. Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario.
(bb) - Los Alamos National Laboratory ECORISK Database. September 2017. http://www.lanl.gov/environment/protection/eco-risk-assessment.php (µg/kg dw)
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http://www.epa.gov/gliclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/TM-96/R2.
http://www.esd.ornl.gov/programs/ecorisk/documents/tm96r2.pdf
(ee) - USEPA. Interim Ecological Soil Screening Level Documents. Accessed October 2018. http://www2.epa.gov/chemical-research/interim-ecological-soil-screening-level-documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter II, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-126/R2. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm126r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-85/R3. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI = 0.2. September 2015. http://portal.ncdenr.org/c/document_library/get_file?uuid=0f601ffa-574d-4479-bbb4-253af0665bf5&groupId=38361
TABLE 2-2
ECOLOGICAL SCREENING - SURFACE WATER - BROAD RIVER - EXPOSURE AREA 1
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Min.Max.Total Dissolved Total Dissolved Total Dissolved Total Dissolved Total Dissolved Total
Aluminum 7429-90-5 32 31 72.9 1,320 1,320 NA NA NA NA 750 (b)NA 87 (b)NA 750 NA 87 NA 87 Y
Antimony 7440-36-0 32 0 ND ND ND NA NA NA NA 900 (cc)NA 190 (cc)NA NA NA NA NA 190 N
Arsenic 7440-38-2 33 32 0.14 4.3 4.3 NA 340 NA 150 340 (b, h)NA 150 (b, h)NA 340 (h)NA 150 (h)NA 150 N
Barium 7440-39-3 33 33 13.1 49.5 49.5 NA NA NA NA 2000 (cc)NA 220 (cc)NA NA NA NA NA 220 N
Beryllium 7440-41-7 32 22 0.01 0.067 0.067 NA 65 NA 6.5 31 (r, cc)NA 3.6 (r, cc)NA NA NA NA NA 4 N
Boron 7440-42-8 33 9 25.5 179 179 NA NA NA NA 34,000 (cc)NA 7,200 (cc)NA NA NA NA NA 7,200 N
Cadmium 7440-43-9 33 2 0.07 0.083 0.083 NA NA NA NA 1.1 (r)NA 0.16 (r)NA NA 1.8 (r)0.27 (r)NA 0.16 N
Chromium (Total)7440-47-3 33 31 0.23 1.6 1.6 NA NA 50 NA 1,022 (n, r)NA 48.8 (n, r)NA NA NA NA NA 50 N
Chromium (VI)18540-29-9 30 27 0.018 1 1 NA 16 NA 11 16 NA 11 NA NA 16 NA 11 11 N
Cobalt 7440-48-4 32 32 0.19 1.4 1.4 NA NA NA NA 120 (cc)NA 19 (cc)NA NA NA NA NA 19 N
Copper 7440-50-8 33 26 0.11 0.97 1 NA NA NA NA 7.3 (r)NA 5.16 (r)NA NA NA NA NA 5.16 N
Lead 7439-92-1 33 33 0.095 0.95 0.95 NA NA NA NA 33.8 (r)NA 1.32 (r)NA NA 65.0 (r)NA 2.5 (r)1 N
Lithium 7439-93-2 2 2 0.62 0.62 0.62 NA NA NA NA 910 (cc)NA 440 (cc)NA NA NA NA NA 440 N
Manganese 7439-96-5 32 32 31 1,040 1,040 NA NA NA NA 1,680 (cc)NA 93 (cc)NA NA NA NA NA 93 Y
Mercury 7439-97-6 33 30 2.76E-04 0.00196 0.00196 NA NA 0.012 NA 1.4 (b, s)NA 0.77 (b, s)NA NA 1.4 (s)NA 0.77 (s)0.012 N
Molybdenum 7439-98-7 32 5 0.11 0.56 0.56 NA NA NA NA 7,200 (cc)NA 800 (cc)NA NA NA NA NA 800 N
Nickel 7440-02-0 33 13 0.32 0.91 0.91 NA NA NA NA 261 (r)NA 29 (r)NA NA 470 (r)NA 52 (r)29 N
Selenium 7782-49-2 33 1 0.41 0.41 0.41 NA NA 5 NA 20 (cc)NA 5 (cc)NA NA NA NA NA 5 N
Strontium 7440-24-6 32 32 18 206 206 NA NA NA NA 48,000 (cc)NA 5,300 (cc)NA NA NA NA NA 5,300 N
Thallium 7440-28-0 34 10 0.019 0.061 0.061 NA NA NA NA 54 (cc)NA 6 (cc)NA NA NA NA NA 6 N
Vanadium 7440-62-2 32 31 0.28 2.9 2.9 NA NA NA NA 79 (cc)NA 27 (cc)NA NA NA NA NA 27 N
Zinc 7440-66-6 33 10 2.6 8.8 8.8 NA NA NA NA 67 (r)NA 67 (r)NA 120 (r)NA 120 (r)NA 67 N
Notes:
AWQC - Ambient Water Quality Criteria DENR - Department of Environment and Natural Resources NC - North Carolina su - Standard units
CAMA - Coal Ash Management Act DHHS - Department of Health and Human Services NCAC - North Carolina Administrative Code µg/L - micrograms/liter
North Carolina Session Law 2014-122, ESV - Ecological Screening Value ORNL - Oak Ridge National Laboratory USEPA - United States Environmental Protection Agency
HH - Human Health PSRG - Preliminary Soil Remediation Goal WS - Water Supply
/Senate/PDF/S729v7.pdf HI - Hazard Index Q - Qualifier < - Concentration not detected at or above the reporting limit
CAS - Chemical Abstracts Service IMAC - Interim Maximum Allowable Concentration RSL - Regional Screening Level
CCC - Criterion Continuous Concentration MCL - Maximum Contaminant Level RSV - Refinement Screening Value
CMC - Criterion Maximum Concentration mg/kg - milligrams/kilogram SMCL - Secondary Maximum Contaminant Level
COPC - Constituent of Potential Concern NA - Not Available SSL - Soil Screening Level
15A NCAC 2B
Freshwater Aquatic
Life Acute (f)
(µg/L)
15A NCAC 2B
Freshwater Aquatic Life
Chronic (f)
(µg/L)
Frequency
of
Detection
Range of
Detection
(µg/L)
Concentration
Used for
Screening
(µg/L)
Prepared by: TCP Checked by: HES
http://www.ncleg.net/Sessions/2013/Bills
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted
USEPA Region 4
Freshwater Acute Screening
Values (g)
(µg/L)
USEPA Region 4
Freshwater Chronic
Screening Values (g)
(µg/L)
USEPA
AWQC (b)
CMC (acute)
(µg/L)
USEPA
AWQC (b)
CCC (chronic)
(µg/L)
Dissolved
Screening
Value Used
(µg/L)
COPC?Analyte CAS
Number
of
Samples
Page 1 of 2
TABLE 2-2
ECOLOGICAL SCREENING - SURFACE WATER - BROAD RIVER - EXPOSURE AREA 1
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
(a) - USEPA Regional Screening Levels (May 2018). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed October 2018.
https://www.epa.gov/risk/regional-screening-levels-rsls-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed October 2018.
https://www.epa.gov/wqc/national-recommended-water-quality-criteria-aquatic-life-criteria-table
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2018 Edition of the Drinking Water Standards and Health Advisories. March 2018. Accessed October 2018.
https://www.epa.gov/sites/production/files/2018-03/documents/dwtable2018.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental
Epidemiology Branch. http://portal.ncdenr.org/c/document_library/get_file?p_l_id=1169848&folderId=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Groundwater Standards & IMACs. http://portal.ncdenr.org/c/document_library/get_file?uuid=1aa3fa13-2c0f-45b7-ae96-5427fb1d25b4&groupId=38364
Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http://reports.oah.state.nc.us/ncac/title%2015a%20-%20environmental%20quality/chapter%2002%20-%20environmental%20management/subchapter%20b/subchapter%20b%20rules.pdf
WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption of fish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stingent of all applicable standards.
(g) - USEPA Region 4. 2018. Region 4 Ecological Risk Assessment Supplemental Guidance. March 2018 Update.
https://www.epa.gov/sites/production/files/2018-03/documents/era_regional_supplemental_guidance_report-march-2018_update.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals
(j) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(l) - Lead Treatment Technology Action Level is 0.015 mg/L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium.
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and
CMC1 and CMC2 are 185.9 µg/L and 12.82 µg/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 µg/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http://www.lanl.gov/community-environment/environmental-stewardship/protection/eco-risk-assessment.php
(y) - Long, Edward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program.
NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bernacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for
Florida Inland Waters. Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario.
(bb) - Los Alamos National Laboratory ECORISK Database. September 2017. http://www.lanl.gov/environment/protection/eco-risk-assessment.php (µg/kg dw)
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http://www.epa.gov/gliclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/TM-96/R2.
http://www.esd.ornl.gov/programs/ecorisk/documents/tm96r2.pdf
(ee) - USEPA. Interim Ecological Soil Screening Level Documents. Accessed October 2018. http://www2.epa.gov/chemical-research/interim-ecological-soil-screening-level-documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter II, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-126/R2. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm126r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-85/R3. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI = 0.2. September 2015. http://portal.ncdenr.org/c/document_library/get_file?uuid=0f601ffa-574d-4479-bbb4-253af0665bf5&groupId=38361
Page 2 of 2
TABLE 2-3
ECOLOGICAL SCREENING - SEDIMENT - SUCK CREEK - EXPOSURE AREA 2
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Min.Max.ESV RSV
Aluminum 7429-90-5 4 4 2,200 11,000 11,000 25,000 (x)58,000 (x)25,000 N
Antimony 7440-36-0 4 0 ND ND ND 2 (y)25 (y)2 N
Arsenic 7440-38-2 4 3 0.47 1.2 1.2 9.8 (z)33 (z)10 N
Barium 7440-39-3 4 4 7.7 41 41 20 (z)60 (z)20 Y
Beryllium 7440-41-7 4 4 0.098 0.43 0.43 NA NA NA N
Boron 7440-42-8 4 0 ND ND ND NA NA NA N
Cadmium 7440-43-9 4 0 ND ND ND 1 (z)5 (z)1 N
Chromium (Total)7440-47-3 4 4 8.2 37.4 37.4 43.4 (z)111 (z)43 N
Chromium (III)16065-83-1 1 1 37.4 37.4 37.4 NA NA NA N
Cobalt 7440-48-4 4 3 1.1 3.2 3.2 50 (aa)NA (aa)50 N
Copper 7440-50-8 4 4 0.96 7.9 7.9 31.6 (z)149 (z)31.6 N
Lead 7439-92-1 4 4 2 5.9 5.9 35.8 (z)128 (z)35.8 N
Manganese 7439-96-5 4 4 22 97.1 97.1 460 (bb)1,100 (bb)460 N
Mercury 7439-97-6 4 0 ND ND ND 0.18 (z)1.1 (z)0.18 N
Molybdenum 7439-98-7 4 0 ND ND ND NA NA NA N
Nickel 7440-02-0 4 4 1.5 8.1 8.1 22.7 (z)48.6 (z)22.7 N
Selenium 7782-49-2 4 0 ND ND ND 0.8 (bb)1.2 (bb)0.8 N
Strontium 7440-24-6 4 3 0.76 2.8 2.8 NA NA NA N
Thallium 7440-28-0 4 3 0.035 0.22 0.22 NA NA NA N
Vanadium 7440-62-2 4 4 5.6 20.7 20.7 NA NA NA N
Zinc 7440-66-6 4 4 5.2 21 21 121 (z)459 (z)121 N
Notes:
AWQC - Ambient Water Quality Criteria DENR - Department of Environment and Natural Resources NC - North Carolina su - Standard units
CAMA - Coal Ash Management Act DHHS - Department of Health and Human Services NCAC - North Carolina Administrative Code µg/L - micrograms/liter
North Carolina Session Law 2014-122, ESV - Ecological Screening Value ORNL - Oak Ridge National Laboratory USEPA - United States Environmental Protection Agency
HH - Human Health PSRG - Preliminary Soil Remediation Goal WS - Water Supply
/Senate/PDF/S729v7.pdf HI - Hazard Index Q - Qualifier < - Concentration not detected at or above the reporting limit
CAS - Chemical Abstracts Service IMAC - Interim Maximum Allowable Concentration RSL - Regional Screening Level j - Indicates concentration reported below Practical Quantitation Limit
CCC - Criterion Continuous Concentration MCL - Maximum Contaminant Level RSV - Refinement Screening Value (PQL) but above Method Detection Limit (MDL) and therefore
CMC - Criterion Maximum Concentration mg/kg - milligrams/kilogram SMCL - Secondary Maximum Contaminant Level concentration is estimated
COPC - Constituent of Potential Concern NA - Not Available SSL - Soil Screening Level
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted Prepared by: TCP Checked by: HES
http://www.ncleg.net/Sessions/2013/Bills
Concentration
Used for
Screening
(mg/kg)
USEPA Region 4 Sediment
Screening Values (g)
(mg/kg)
Screening
Value Used
(mg/kg)
COPC?Analyte CAS Number of
Samples
Frequency
of
Detection
Range of Detection
(mg/kg)
TABLE 2-3
ECOLOGICAL SCREENING - SEDIMENT - SUCK CREEK - EXPOSURE AREA 2
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
(a) - USEPA Regional Screening Levels (May 2018). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed October 2018.
https://www.epa.gov/risk/regional-screening-levels-rsls-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed October 2018.
https://www.epa.gov/wqc/national-recommended-water-quality-criteria-aquatic-life-criteria-table
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2018 Edition of the Drinking Water Standards and Health Advisories. March 2018. Accessed October 2018.
https://www.epa.gov/sites/production/files/2018-03/documents/dwtable2018.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental
Epidemiology Branch. http://portal.ncdenr.org/c/document_library/get_file?p_l_id=1169848&folderId=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Groundwater Standards & IMACs. http://portal.ncdenr.org/c/document_library/get_file?uuid=1aa3fa13-2c0f-45b7-ae96-5427fb1d25b4&groupId=38364
Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http://reports.oah.state.nc.us/ncac/title%2015a%20-%20environmental%20quality/chapter%2002%20-%20environmental%20management/subchapter%20b/subchapter%20b%20rules.pdf
WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption of fish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stingent of all applicable standards.
(g) - USEPA Region 4. 2018. Region 4 Ecological Risk Assessment Supplemental Guidance. March 2018 Update.
https://www.epa.gov/sites/production/files/2018-03/documents/era_regional_supplemental_guidance_report-march-2018_update.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals
(j) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(l) - Lead Treatment Technology Action Level is 0.015 mg/L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium.
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and
CMC1 and CMC2 are 185.9 µg/L and 12.82 µg/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 µg/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http://www.lanl.gov/community-environment/environmental-stewardship/protection/eco-risk-assessment.php
(y) - Long, Edward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program.
NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bernacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for
Florida Inland Waters. Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario.
(bb) - Los Alamos National Laboratory ECORISK Database. September 2017. http://www.lanl.gov/environment/protection/eco-risk-assessment.php (µg/kg dw)
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http://www.epa.gov/gliclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/TM-96/R2.
http://www.esd.ornl.gov/programs/ecorisk/documents/tm96r2.pdf
(ee) - USEPA. Interim Ecological Soil Screening Level Documents. Accessed October 2018. http://www2.epa.gov/chemical-research/interim-ecological-soil-screening-level-documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter II, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-126/R2. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm126r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-85/R3. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI = 0.2. September 2015. http://portal.ncdenr.org/c/document_library/get_file?uuid=0f601ffa-574d-4479-bbb4-253af0665bf5&groupId=38361
TABLE 2-4
ECOLOGICAL SCREENING - SURFACE WATER - SUCK CREEK - EXPOSURE AREA 2
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Min.Max.Total Dissolved Total Dissolved Total Dissolved Total Dissolved Total Dissolved Total
Aluminum 7429-90-5 36 35 77.4 219 219 NA NA NA NA 750 (b)NA 87 (b)NA 750 NA 87 NA 87 Y
Antimony 7440-36-0 36 1 0.17 0.17 0.17 NA NA NA NA 900 (cc)NA 190 (cc)NA NA NA NA NA 190 N
Arsenic 7440-38-2 36 35 0.18 0.6 0.6 NA 340 NA 150 340 (b, h)NA 150 (b, h)NA 340 (h)NA 150 (h)NA 150 N
Barium 7440-39-3 36 36 18.8 60.6 60.6 NA NA NA NA 2,000 (cc)NA 220 (cc)NA NA NA NA NA 220 N
Beryllium 7440-41-7 36 31 0.01 0.044 0.044 NA 65 NA 6.5 31 (r, cc)NA 3.6 (r, cc)NA NA NA NA NA 4 N
Boron 7440-42-8 36 23 25.8 79.8 79.8 NA NA NA NA 34,000 (cc)NA 7,200 (cc)NA NA NA NA NA 7,200 N
Cadmium 7440-43-9 36 0 ND ND ND NA NA NA NA 1.1 (r)NA 0.16 (r)NA NA 1.8 (r)0.27 (r)NA 0.16 N
Chromium (Total)7440-47-3 36 35 0.16 2.4 2.4 NA NA 50 NA 1,022 (n, r)NA 48.8 (n, r)NA NA NA NA NA 50 N
Chromium (VI)18540-29-9 33 25 0.019 0.56 0.56 NA 16 NA 11 16 NA 11 NA NA 16 NA 11 11 N
Cobalt 7440-48-4 36 36 0.18 3.4 3.4 NA NA NA NA 120 (cc)NA 19 (cc)NA NA NA NA NA 19 N
Copper 7440-50-8 36 29 0.29 1.9 1.9 NA NA NA NA 7.3 (r)NA 5.16 (r)NA NA NA NA NA 5.16 N
Lead 7439-92-1 36 36 0.11 0.49 0.49 NA NA NA NA 33.8 (r)NA 1.32 (r)NA NA 65.0 (r)NA 2.5 (r)1 N
Lithium 7439-93-2 2 2 0.62 0.67 0.67 NA NA NA NA 910 (cc)NA 440 (cc)NA NA NA NA NA 440 N
Manganese 7439-96-5 36 36 30 288 288 NA NA NA NA 1,680 (cc)NA 93 (cc)NA NA NA NA NA 93 Y
Mercury 7439-97-6 36 34 6.07E-04 0.00226 0.00226 NA NA 0.012 NA 1.4 (b, s)NA 0.77 (b, s)NA NA 1.4 (s)NA 0.77 (s)0.012 N
Molybdenum 7439-98-7 36 2 0.13 0.71 0.71 NA NA NA NA 7,200 (cc)NA 800 (cc)NA NA NA NA NA 800 N
Nickel 7440-02-0 36 28 0.37 2.4 2.4 NA NA NA NA 261 (r)NA 29 (r)NA NA 470 (r)NA 52 (r)29 N
Selenium 7782-49-2 36 3 0.21 0.4 0.4 NA NA 5 NA 20 (cc)NA 5 (cc)NA NA NA NA NA 5 N
Strontium 7440-24-6 36 36 18.6 51.4 51.4 NA NA NA NA 48,000 (cc)NA 5,300 (cc)NA NA NA NA NA 5,300 N
Thallium 7440-28-0 36 15 0.016 0.069 0.069 NA NA NA NA 54 (cc)NA 6 (cc)NA NA NA NA NA 6 N
Vanadium 7440-62-2 36 34 0.12 0.98 0.98 NA NA NA NA 79 (cc)NA 27 (cc)NA NA NA NA NA 27 N
Zinc 7440-66-6 36 15 2.5 12.1 12.1 NA NA NA NA 67 (r)NA 67 (r)NA 120 (r)NA 120 (r)NA 67 N
Notes:
AWQC - Ambient Water Quality Criteria DENR - Department of Environment and Natural Resources NC - North Carolina su - Standard units
CAMA - Coal Ash Management Act DHHS - Department of Health and Human Services NCAC - North Carolina Administrative Code µg/L - micrograms/liter
North Carolina Session Law 2014-122, ESV - Ecological Screening Value ORNL - Oak Ridge National Laboratory USEPA - United States Environmental Protection Agency
HH - Human Health PSRG - Preliminary Soil Remediation Goal WS - Water Supply
/Senate/PDF/S729v7.pdf HI - Hazard Index Q - Qualifier < - Concentration not detected at or above the reporting limit
CAS - Chemical Abstracts Service IMAC - Interim Maximum Allowable Concentration RSL - Regional Screening Level j - Indicates concentration reported below Practical Quantitation Limit
CCC - Criterion Continuous Concentration MCL - Maximum Contaminant Level RSV - Refinement Screening Value (PQL) but above Method Detection Limit (MDL) and therefore concentration is estimated
CMC - Criterion Maximum Concentration mg/kg - milligrams/kilogram SMCL - Secondary Maximum Contaminant Level
COPC - Constituent of Potential Concern NA - Not Available SSL - Soil Screening Level
Prepared by: HEG Checked by: HES
http://www.ncleg.net/Sessions/2013/Bills
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted
USEPA Region 4
Freshwater Acute Screening
Values (g)
(µg/L)
USEPA Region 4
Freshwater Chronic
Screening Values (g)
(µg/L)
USEPA
AWQC (b)
CMC (acute)
(µg/L)
USEPA
AWQC (b)
CCC (chronic)
(µg/L)
Dissolved
Screening
Value Used
(µg/L)
COPC?Analyte CAS
Number
of
Samples
15A NCAC 2B
Freshwater Aquatic
Life Acute (f)
(µg/L)
15A NCAC 2B
Freshwater Aquatic Life
Chronic (f)
(µg/L)
Frequency
of
Detection
Range of
Detection
(µg/L)
Concentration
Used for
Screening
(µg/L)
Page 1 of 2
TABLE 2-4
ECOLOGICAL SCREENING - SURFACE WATER - SUCK CREEK - EXPOSURE AREA 2
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
(a) - USEPA Regional Screening Levels (May 2018). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed October 2018.
https://www.epa.gov/risk/regional-screening-levels-rsls-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed October 2018.
https://www.epa.gov/wqc/national-recommended-water-quality-criteria-aquatic-life-criteria-table
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2018 Edition of the Drinking Water Standards and Health Advisories. March 2018. Accessed October 2018.
https://www.epa.gov/sites/production/files/2018-03/documents/dwtable2018.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental
Epidemiology Branch. http://portal.ncdenr.org/c/document_library/get_file?p_l_id=1169848&folderId=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Groundwater Standards & IMACs. http://portal.ncdenr.org/c/document_library/get_file?uuid=1aa3fa13-2c0f-45b7-ae96-5427fb1d25b4&groupId=38364
Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http://reports.oah.state.nc.us/ncac/title%2015a%20-%20environmental%20quality/chapter%2002%20-%20environmental%20management/subchapter%20b/subchapter%20b%20rules.pdf
WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption of fish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stingent of all applicable standards.
(g) - USEPA Region 4. 2018. Region 4 Ecological Risk Assessment Supplemental Guidance. March 2018 Update.
https://www.epa.gov/sites/production/files/2018-03/documents/era_regional_supplemental_guidance_report-march-2018_update.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals
(j) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(l) - Lead Treatment Technology Action Level is 0.015 mg/L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium.
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and
CMC1 and CMC2 are 185.9 µg/L and 12.82 µg/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 µg/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http://www.lanl.gov/community-environment/environmental-stewardship/protection/eco-risk-assessment.php
(y) - Long, Edward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program.
NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bernacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for
Florida Inland Waters. Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario.
(bb) - Los Alamos National Laboratory ECORISK Database. September 2017. http://www.lanl.gov/environment/protection/eco-risk-assessment.php (µg/kg dw)
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http://www.epa.gov/gliclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/TM-96/R2.
http://www.esd.ornl.gov/programs/ecorisk/documents/tm96r2.pdf
(ee) - USEPA. Interim Ecological Soil Screening Level Documents. Accessed October 2018. http://www2.epa.gov/chemical-research/interim-ecological-soil-screening-level-documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter II, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-126/R2. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm126r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-85/R3. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI = 0.2. September 2015. http://portal.ncdenr.org/c/document_library/get_file?uuid=0f601ffa-574d-4479-bbb4-253af0665bf5&groupId=38361
Page 2 of 2
TABLE 2-5
ECOLOGICAL SCREENING - SEDIMENT - BROAD RIVER - EXPOSURE AREA 4
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Min.Max.ESV RSV
Aluminum 7429-90-5 2 0 ND ND ND 25,000 (x)58,000 (x)25,000 N
Antimony 7440-36-0 2 2 0.58 0.73 0.73 2 (y)25 (y)2 N
Arsenic 7440-38-2 2 2 1.2 3.9 3.9 9.8 (z)33 (z)10 N
Barium 7440-39-3 2 2 27 160 160 20 (z)60 (z)20 Y
Beryllium 7440-41-7 2 0 ND ND ND NA NA NA N
Boron 7440-42-8 2 1 9.7 9.7 9.7 NA NA NA N
Cadmium 7440-43-9 2 2 0.15 0.24 0.24 1 (z)5 (z)1 N
Chromium (Total)7440-47-3 2 2 17 38 38 43.4 (z)111 (z)43 N
Chromium (III)16065-83-1 2 2 1 1 1 NA NA NA N
Cobalt 7440-48-4 2 2 2.2 9.9 9.9 50 (aa)NA (aa)50 N
Copper 7440-50-8 2 2 4.1 21 21 31.6 (z)149 (z)31.6 N
Lead 7439-92-1 2 2 4.5 16 16 35.8 (z)128 (z)35.8 N
Manganese 7439-96-5 2 0 ND ND ND 460 (bb)1,100 (bb)460 N
Mercury 7439-97-6 2 0 ND ND ND 0.18 (z)1.1 (z)0.18 N
Molybdenum 7439-98-7 2 2 2.2 7.8 7.8 NA NA NA N
Nickel 7440-02-0 2 0 ND ND ND 22.7 (z)48.6 (z)22.7 N
Selenium 7782-49-2 2 0 ND ND ND 0.8 (bb)1.2 (bb)0.8 N
Strontium 7440-24-6 2 2 1.5 16 16 NA NA NA N
Thallium 7440-28-0 2 2 0.093 0.41 0.41 NA NA NA N
Vanadium 7440-62-2 2 2 16 60 60 NA NA NA N
Zinc 7440-66-6 2 2 14 74 74 121 (z)459 (z)121 N
Notes:
AWQC - Ambient Water Quality Criteria DENR - Department of Environment and Natural ResourcesNC - North Carolina su - Standard units
CAMA - Coal Ash Management Act DHHS - Department of Health and Human Services NCAC - North Carolina Administrative Code µg/L - micrograms/liter
North Carolina Session Law 2014-122, ESV - Ecological Screening Value ORNL - Oak Ridge National Laboratory USEPA - United States Environmental Protection Agency
HH - Human Health PSRG - Preliminary Soil Remediation Goal WS - Water Supply
/Senate/PDF/S729v7.pdf HI - Hazard Index Q - Qualifier < - Concentration not detected at or above the reporting limit
CAS - Chemical Abstracts Service IMAC - Interim Maximum Allowable Concentration RSL - Regional Screening Level j - Indicates concentration reported below Practical Quantitation Limit
CCC - Criterion Continuous Concentration MCL - Maximum Contaminant Level RSV - Refinement Screening Value (PQL) but above Method Detection Limit (MDL) and therefore concentration is
CMC - Criterion Maximum Concentration mg/kg - milligrams/kilogram SMCL - Secondary Maximum Contaminant Level estimated
COPC - Constituent of Potential Concern NA - Not Available SSL - Soil Screening Level
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted Prepared by: TCP Checked by: HES
http://www.ncleg.net/Sessions/2013/Bills
Concentration
Used for
Screening
(mg/kg)
USEPA Region 4 Sediment
Screening Values (g)
(mg/kg)
Screening
Value Used
(mg/kg)
COPC?Analyte CAS Number of
Samples
Frequency
of
Detection
Range of
Detection
(mg/kg)
TABLE 2-5
ECOLOGICAL SCREENING - SEDIMENT - BROAD RIVER - EXPOSURE AREA 4
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
(a) - USEPA Regional Screening Levels (May 2018). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed October 2018.
https://www.epa.gov/risk/regional-screening-levels-rsls-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed October 2018.
https://www.epa.gov/wqc/national-recommended-water-quality-criteria-aquatic-life-criteria-table
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2018 Edition of the Drinking Water Standards and Health Advisories. March 2018. Accessed October 2018.
https://www.epa.gov/sites/production/files/2018-03/documents/dwtable2018.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental
Epidemiology Branch. http://portal.ncdenr.org/c/document_library/get_file?p_l_id=1169848&folderId=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Groundwater Standards & IMACs. http://portal.ncdenr.org/c/document_library/get_file?uuid=1aa3fa13-2c0f-45b7-ae96-5427fb1d25b4&groupId=38364
Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http://reports.oah.state.nc.us/ncac/title%2015a%20-%20environmental%20quality/chapter%2002%20-%20environmental%20management/subchapter%20b/subchapter%20b%20rules.pdf
WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption of fish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stingent of all applicable standards.
(g) - USEPA Region 4. 2018. Region 4 Ecological Risk Assessment Supplemental Guidance. March 2018 Update.
https://www.epa.gov/sites/production/files/2018-03/documents/era_regional_supplemental_guidance_report-march-2018_update.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals
(j) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(l) - Lead Treatment Technology Action Level is 0.015 mg/L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium.
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and
CMC1 and CMC2 are 185.9 µg/L and 12.82 µg/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 µg/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http://www.lanl.gov/community-environment/environmental-stewardship/protection/eco-risk-assessment.php
(y) - Long, Edward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program.
NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bernacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for
Florida Inland Waters. Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario.
(bb) - Los Alamos National Laboratory ECORISK Database. September 2017. http://www.lanl.gov/environment/protection/eco-risk-assessment.php (µg/kg dw)
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http://www.epa.gov/gliclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/TM-96/R2.
http://www.esd.ornl.gov/programs/ecorisk/documents/tm96r2.pdf
(ee) - USEPA. Interim Ecological Soil Screening Level Documents. Accessed October 2018. http://www2.epa.gov/chemical-research/interim-ecological-soil-screening-level-documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter II, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-126/R2. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm126r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-85/R3. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI = 0.2. September 2015. http://portal.ncdenr.org/c/document_library/get_file?uuid=0f601ffa-574d-4479-bbb4-253af0665bf5&groupId=38361
TABLE 2-6
ECOLOGICAL SCREENING - SURFACE WATER - BROAD RIVER - EXPOSURE AREA 4
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Min.Max.Total Dissolved Total Dissolved Total Dissolved Total Dissolved Total Dissolved Total
Aluminum 7429-90-5 4 4 171 299 299 NA NA NA NA 750 (b)NA 87 (b)NA 750 NA 87 NA 87 Y
Antimony 7440-36-0 4 0 ND ND ND NA NA NA NA 900 (cc)NA 190 (cc)NA NA NA NA NA 190 N
Arsenic 7440-38-2 5 4 0.12 0.2 0.2 NA 340 NA 150 340 (b, h)NA 150 (b, h)NA 340 (h)NA 150 (h)NA 150 N
Barium 7440-39-3 5 5 13.5 17 17 NA NA NA NA 2000 (cc)NA 220 (cc)NA NA NA NA NA 220 N
Beryllium 7440-41-7 4 2 0.012 0.024 0.024 NA 65 NA 6.5 31 (r, cc)NA 3.6 (r, cc)NA NA NA NA NA 4 N
Boron 7440-42-8 5 0 ND ND ND NA NA NA NA 34,000 (cc)NA 7,200 (cc)NA NA NA NA NA 7,200 N
Cadmium 7440-43-9 5 0 ND ND ND NA NA NA NA 1.1 (r)NA 0.16 (r)NA NA 1.8 (r)0.27 (r)NA 0.16 N
Chromium (Total)7440-47-3 5 4 0.47 0.51 0.51 NA NA 50 NA 1,022 (n, r)NA 48.8 (n, r)NA NA NA NA NA 50 N
Chromium (VI)18540-29-9 4 4 0.073 0.081 0.081 NA 16 NA 11 16 NA 11 NA NA 16 NA 11 11 N
Cobalt 7440-48-4 4 4 0.12 0.16 0.16 NA NA NA NA 120 (cc)NA 19 (cc)NA NA NA NA NA 19 N
Copper 7440-50-8 5 4 0.33 0.7 0.7 NA NA NA NA 7.3 (r)NA 5.16 (r)NA NA NA NA NA 5.16 N
Lead 7439-92-1 5 5 0.15 0.325 0.325 NA NA NA NA 33.8 (r)NA 1.32 (r)NA NA 65.0 (r)NA 2.5 (r)1 N
Lithium 7439-93-2 0 0 ND ND ND NA NA NA NA 910 (cc)NA 440 (cc)NA NA NA NA NA 440 N
Manganese 7439-96-5 4 4 26.8 31.3 31.3 NA NA NA NA 1,680 (cc)NA 93 (cc)NA NA NA NA NA 93 N
Mercury 7439-97-6 5 5 8.00E-04 0.00115 0.00115 NA NA 0.012 NA 1.4 (b, s)NA 0.77 (b, s)NA NA 1.4 (s)NA 0.77 (s)0.012 N
Molybdenum 7439-98-7 4 0 ND ND ND NA NA NA NA 7,200 (cc)NA 800 (cc)NA NA NA NA NA 800 N
Nickel 7440-02-0 5 0 ND ND ND NA NA NA NA 261 (r)NA 29 (r)NA NA 470 (r)NA 52 (r)29 N
Selenium 7782-49-2 5 0 ND ND ND NA NA 5 NA 20 (cc)NA 5 (cc)NA NA NA NA NA 5 N
Strontium 7440-24-6 4 4 23.6 26.7 26.7 NA NA NA NA 48,000 (cc)NA 5,300 (cc)NA NA NA NA NA 5,300 N
Thallium 7440-28-0 5 1 0.056 0.056 0.056 NA NA NA NA 54 (cc)NA 6 (cc)NA NA NA NA NA 6 N
Vanadium 7440-62-2 4 4 0.88 1.2 1.2 NA NA NA NA 79 (cc)NA 27 (cc)NA NA NA NA NA 27 N
Zinc 7440-66-6 5 3 3.4 22.9 22.9 NA NA NA NA 67 (r)NA 67 (r)NA 120 (r)NA 120 (r)NA 67 N
Notes:
AWQC - Ambient Water Quality Criteria DENR - Department of Environment and Natural Resources NC - North Carolina su - Standard units
CAMA - Coal Ash Management Act DHHS - Department of Health and Human Services NCAC - North Carolina Administrative Code µg/L - micrograms/liter
North Carolina Session Law 2014-122, ESV - Ecological Screening Value ORNL - Oak Ridge National Laboratory USEPA - United States Environmental Protection Agency
HH - Human Health PSRG - Preliminary Soil Remediation Goal WS - Water Supply
/Senate/PDF/S729v7.pdf HI - Hazard Index Q - Qualifier < - Concentration not detected at or above the reporting limit
CAS - Chemical Abstracts Service IMAC - Interim Maximum Allowable Concentration RSL - Regional Screening Level j - Indicates concentration reported below Practical Quantitation Limit
CCC - Criterion Continuous Concentration MCL - Maximum Contaminant Level RSV - Refinement Screening Value (PQL) but above Method Detection Limit (MDL) and therefore concentration is estimated
CMC - Criterion Maximum Concentration mg/kg - milligrams/kilogram SMCL - Secondary Maximum Contaminant Level
COPC - Constituent of Potential Concern NA - Not Available SSL - Soil Screening Level
Prepared by: TCP Checked by: HES
http://www.ncleg.net/Sessions/2013/Bills
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted
USEPA Region 4
Freshwater Acute Screening
Values (g)
(µg/L)
USEPA Region 4
Freshwater Chronic
Screening Values (g)
(µg/L)
USEPA
AWQC (b)
CMC (acute)
(µg/L)
USEPA
AWQC (b)
CCC (chronic)
(µg/L)
Dissolved
Screening
Value Used
(µg/L)
COPC?Analyte CAS
Number
of
Samples
15A NCAC 2B
Freshwater Aquatic
Life Acute (f)
(µg/L)
15A NCAC 2B
Freshwater Aquatic Life
Chronic (f)
(µg/L)
Frequency
of
Detection
Range of
Detection
(µg/L)
Concentration
Used for
Screening
(µg/L)
Page 1 of 2
TABLE 2-6
ECOLOGICAL SCREENING - SURFACE WATER - BROAD RIVER - EXPOSURE AREA 4
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
(a) - USEPA Regional Screening Levels (May 2018). Values for Residential Soil, Industrial Soil, and Tap Water. HI = 0.2. Accessed October 2018.
https://www.epa.gov/risk/regional-screening-levels-rsls-generic-tables
(b) - USEPA National Recommended Water Quality Criteria. USEPA Office of Water and Office of Science and Technology. Accessed October 2018.
https://www.epa.gov/wqc/national-recommended-water-quality-criteria-aquatic-life-criteria-table
USEPA AWQC Human Health for the Consumption of Organism Only apply to total concentrations.
(c) - USEPA 2018 Edition of the Drinking Water Standards and Health Advisories. March 2018. Accessed October 2018.
https://www.epa.gov/sites/production/files/2018-03/documents/dwtable2018.pdf
(d) - DHHS Screening Levels. Department of Health and Human Services, Division of Public Health, Epidemiology Section, Occupational and Environmental
Epidemiology Branch. http://portal.ncdenr.org/c/document_library/get_file?p_l_id=1169848&folderId=24814087&name=DLFE-112704.pdf
(e) - North Carolina 15A NCAC 02L .0202 Groundwater Standards & IMACs. http://portal.ncdenr.org/c/document_library/get_file?uuid=1aa3fa13-2c0f-45b7-ae96-5427fb1d25b4&groupId=38364
Amended April 2013.
(f) - North Carolina 15A NCAC 02B Surface Water and Wetland Standards. Amended January 1, 2015.
http://reports.oah.state.nc.us/ncac/title%2015a%20-%20environmental%20quality/chapter%2002%20-%20environmental%20management/subchapter%20b/subchapter%20b%20rules.pdf
WS standards are applicable to all Water Supply Classifications. WS standards are based on the consumption of fish and water.
Human Health Standards are based on the consumption of fish only unless dermal contact studies are available.
For Class C, use the most stringent of freshwater (or, if applicable, saltwater) column and the Human Health column.
For a WS water, use the most stringent of Freshwater, WS and Human Health. Likewise, Trout Waters and High Quality Waters must adhere to the most stingent of all applicable standards.
(g) - USEPA Region 4. 2018. Region 4 Ecological Risk Assessment Supplemental Guidance. March 2018 Update.
https://www.epa.gov/sites/production/files/2018-03/documents/era_regional_supplemental_guidance_report-march-2018_update.pdf
(h) - Value applies to inorganic form of arsenic only.
(i) - Value is the Secondary Maximum Contaminant Level.
https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidance-nuisance-chemicals
(j) - Value for Total Chromium.
(k) - Copper Treatment Technology Action Level is 1.3 mg/L.
(l) - Lead Treatment Technology Action Level is 0.015 mg/L.
(m) - RSL for Antimony (metallic) used for Antimony.
(n) - Value for Chromium (III), Insoluble Salts used for Chromium.
(o) - RSL for Mercuric Chloride used for Mercury.
(p) - RSL for Nickel Soluble Salts used for Nickel.
(q) - RSL for Thallium (Soluble Salts) used for Thallium.
(r) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(s) - Value for Inorganic Mercury.
(t) - Acute AWQC is equal to 1/[(f1/CMC1) + (f2/CMC2)] where f1 and f2 are the fractions of total selenium that are treated as selenite and selenate, respectively, and
CMC1 and CMC2 are 185.9 µg/L and 12.82 µg/L, respectively. Calculated assuming that all selenium is present as selenate, a likely overly conservative assumption.
(u) - Criterion expressed as a function of total hardness (mg/L). Value displayed is the site-specific total hardness of mg/L.
(v) - Chloride Action Level for Toxic Substances Applicable to NPDES Permits is 230,000 µg/L.
(w) - Applicable only to persons with a sodium restrictive diet.
(x) - Los Alamos National Laboratory ECORISK Database. http://www.lanl.gov/community-environment/environmental-stewardship/protection/eco-risk-assessment.php
(y) - Long, Edward R., and Lee G. Morgan. 1991. The Potential for Biological Effects of Sediment-Sorbed Contaminants Tested in the National Status and Trends Program.
NOAA Technical Memorandum NOS OMA 52. Used effects range low (ER-L) for chronic and effects range medium (ER-M) for acute.
(z) - MacDonald, D.D.; Ingersoll, C.G.; Smorong, D.E.; Lindskoog, R.A.; Sloane, G.; and T. Bernacki. 2003. Development and Evaluation of Numerical Sediment Quality Assessment Guidelines for
Florida Inland Waters. Florida Department of Environmental Protection, Tallahassee, FL. Used threshold effect concentration (TEC) for the ESV and probable effect concentration (PEC) for the RSV.
(aa) - Persaud, D., R. Jaagumagi and A. Hayton. 1993. Guidelines for the protection and management of aquatic sediment quality in Ontario. Ontario Ministry of the Environment. Queen's Printer of Ontario.
(bb) - Los Alamos National Laboratory ECORISK Database. September 2017. http://www.lanl.gov/environment/protection/eco-risk-assessment.php (µg/kg dw)
(cc) - Great Lakes Initiative (GLI) Clearinghouse resources Tier II criteria revised 2013. http://www.epa.gov/gliclearinghouse/
(dd) - Suter, G.W., and Tsao, C.L. 1996. Toxicological Benchmarks for Screening Potential Contaminants of Concern for Effects on Aquatic Biota: 1996 Revision. ES/ER/TM-96/R2.
http://www.esd.ornl.gov/programs/ecorisk/documents/tm96r2.pdf
(ee) - USEPA. Interim Ecological Soil Screening Level Documents. Accessed October 2018. http://www2.epa.gov/chemical-research/interim-ecological-soil-screening-level-documents
(ff) - Efroymson, R.A., M.E. Will, and G.W. Suter II, 1997a. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-126/R2. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm126r21.pdf)
(gg) - Efroymson, R.A., M.E. Will, G.W. Suter II, and A.C. Wooten, 1997b. Toxicological Benchmarks for Screening Contaminants of Potential Concern for Effects on Terrestrial Plants:
1997 Revision. Oak Ridge National Laboratory, Oak Ridge, TN. ES/ER/TM-85/R3. (Available at http://www.esd.ornl.gov/programs/ecorisk/documents/tm85r3.pdf)
(hh) - North Carolina Preliminary Soil Remediation Goals (PSRG) Table. HI = 0.2. September 2015. http://portal.ncdenr.org/c/document_library/get_file?uuid=0f601ffa-574d-4479-bbb4-253af0665bf5&groupId=38361
Page 2 of 2
TABLE 3-1
SUMMARY OF EXPOSURE POINT CONCENTRATIONS
HUMAN HEALTH - GROUNDWATER
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Constituent Reporting
Units
Number of
Samples
Frequency of
Detection
Minimum
Detected
Concentration
Maximum
Detected
Concentration
Mean of
Detected
Concentration
UCL Selected UCL Exposure Point
Concentration
Exposure Point
Concentration
(mg/L)
Aluminum µg/L 1,539 1,080 5 128,000 871.4 95% KM (Chebyshev) UCL 1,065 1065 1.065
Antimony µg/L 2,003 629 0.1 94.9 1.527 95% KM (Chebyshev) UCL 0.95 0.95 0.00095
Arsenic µg/L 2,075 1,708 0.04 4,680 27.72 95% KM (Chebyshev) UCL 49.44 49.44 0.04944
Barium µg/L 2,086 2,036 2.5 5,090 65.73 95% KM (Chebyshev) UCL 87.36 87.36 0.08736
Beryllium µg/L 1,942 1,161 0.01 98.6 0.569 95% KM (Chebyshev) UCL 0.607 0.607 0.000607
Boron µg/L 2,089 1,371 25 2,750 347.5 95% KM (Chebyshev) UCL 277.1 277.1 0.2771
Cadmium µg/L 2,075 619 0.026 94.1 0.397 95% KM (Chebyshev) UCL 0.361 0.361 0.000361
Chromium (Total)µg/L 2,063 1,765 0.092 838 5.773 95% KM (Chebyshev) UCL 7.452 7.452 0.007452
Chromium (VI)µg/L 1,267 799 0.0083 25.2 0.818 95% KM (Chebyshev) UCL 0.741 0.741 0.000741
Cobalt µg/L 1,942 1,803 0.01 895 16.84 95% KM (Chebyshev) UCL 20.24 20.24 0.02024
Lead µg/L 2,075 1,057 0.028 84.3 0.729 95% KM (Chebyshev) UCL 0.681 0.681 0.000681
Lithium µg/L 693 673 0.17 467 8.182 95% KM (Chebyshev) UCL 12.46 12.46 0.01246
Manganese µg/L 1,684 1,612 2.5 37,000 1,279 95% KM (Chebyshev) UCL 1,515 1515 1.515
Mercury µg/L 2,081 159 0.05 13 0.44 95% KM (Chebyshev) UCL 0.136 0.136 0.000136
Molybdenum µg/L 1,947 1,103 0.081 337 5.79 95% KM (Chebyshev) UCL 4.856 4.856 0.004856
Nickel µg/L 1,661 1,391 0.14 380 9.092 95% KM (Chebyshev) UCL 9.879 9.879 0.009879
Selenium µg/L 2,075 821 0.17 117 5.47 95% KM (Chebyshev) UCL 3.262 3.262 0.003262
Strontium µg/L 1,539 1,534 3.4 40,400 402.7 95% KM (Chebyshev) UCL 640.2 640.2 0.6402
Thallium µg/L 2,001 1,144 0.015 5.6 0.239 95% KM (Chebyshev) UCL 0.194 0.194 0.000194
Vanadium µg/L 1,523 1,094 0.058 207 2.944 95% KM (Chebyshev) UCL 3.318 3.318 0.003318
Zinc µg/L 1,672 1,107 2.447 870 20.1 95% KM (Chebyshev) UCL 18.73 18.73 0.01873
Notes:
---: Calculations were not performed due to lack of samples ND - Not Determined
Mean - Arithmetic mean UCL - 95% Upper Confidence Limit
mg/L - milligrams per liter
µg/L - micrograms per liter
(c) - 0 is defined as a number of samples analyzed or the frequency of detection among samples.
(a)- Mean calculated by ProUCL using the Kaplan-Meier (KM) estimation method for non-detect values: only given for datasets with FOD less than 100% and that met the minimum sample size and FOD requirements for use with
ProUCL; see note (b).
(b)- Sample size was greater than or equal to 10 and the number of detected values was greater than or equal to 6, therefore, a 95% UCL was calculated by ProUCL. The UCL shown is the one recommended by ProUCL. If more than
one UCL was recommended, the higher UCL was selected. ProUCL, version 5.0
(d) - The 95% UCL values are calculated using the ProUCL software (V. 5.0; USEPA, 2013a). The ProUCL software performs a goodness-of-fit test that accounts for data sets without any non-detect observations, as well as data sets with non-detect
observations. The software then determines the distribution of the data set for which the EPC is being derived (e.g., normal, lognormal, gamma, or non-discernable), and then calculates a conservative and stable 95% UCL value in accordance with the
framework described in “Calculating Upper Confidence Limits for Exposure Point Concentrations at Hazardous Waste Sites” (USEPA, 2002b). The software includes numerous algorithms for calculating 95% UCL values, and provides a recommended UCL value
based on the algorithm that is most applicable to the statistical distribution of the data set. ProUCL will calculate a 95% UCL where there are 3 or more total samples with detected concentrations. Where too few samples or detects are available, the maximum
detected concentration is used as the EPC.
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted Prepared by: HEG Checked by: HES
TABLE 3-2
SUMMARY OF EXPOSURE POINT CONCENTRATIONS
HUMAN HEALTH - SEDIMENT
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Constituent Reporting
Units
Number of
Samples
Frequency of
Detection
Minimum
Detected
Concentration
Maximum
Detected
Concentration
Mean Detected
Concentration UCL Selected UCL
Exposure Point
Concentration
(mg/kg)
Aluminum mg/kg 15 15 2,200 40,000 14,689 95% Adjusted Gamma UCL 23,844 23,844
Arsenic mg/kg 15 13 0.47 3.9 1.406 95% KM (t) UCL 1.85 1.85
Cobalt mg/kg 15 13 1.1 12 5.669 95% KM (t) UCL 6.914 6.914
Manganese mg/kg 15 15 22 780 234.2 95% Adjusted Gamma UCL 437.6 437.6
Thallium mg/kg 15 13 0.035 0.5 0.237 95% KM (t) UCL 0.303 0.303
Notes:
---: Calculations were not performed due to lack of samples ND - Not Determined
Mean - Arithmetic mean UCL - 95% Upper Confidence Limit
mg/kg - milligrams per kilogram
(c) - 0 is defined as a number of samples analyzed or the frequency of detection among samples.
(a)- Mean calculated by ProUCL using the Kaplan-Meier (KM) estimation method for non-detect values: only given for datasets with FOD less than 100% and that met the minimum sample size and FOD requirements for use with ProUCL; see
note (b).
(b)- Sample size was greater than or equal to 10 and the number of detected values was greater than or equal to 6, therefore, a 95% UCL was calculated by ProUCL. The UCL shown is the one recommended by ProUCL. If more than one UCL was
recommended, the higher UCL was selected. ProUCL, version 5.0
(d) - The 95% UCL values are calculated using the ProUCL software (V. 5.0; USEPA, 2013a). The ProUCL software performs a goodness-of-fit test that accounts for data sets without any non-detect observations, as well as data sets with non-
detect observations. The software then determines the distribution of the data set for which the EPC is being derived (e.g., normal, lognormal, gamma, or non-discernable), and then calculates a conservative and stable 95% UCL value in
accordance with the framework described in “Calculating Upper Confidence Limits for Exposure Point Concentrations at Hazardous Waste Sites” (USEPA, 2002b). The software includes numerous algorithms for calculating 95% UCL values, and
provides a recommended UCL value based on the algorithm that is most applicable to the statistical distribution of the data set. ProUCL will calculate a 95% UCL where there are 3 or more total samples with detected concentrations. Where too
few samples or detects are available, the maximum detected concentration is used as the EPC.
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted Prepared by: HEG Checked by: HES
TABLE 3-3
SUMMARY OF EXPOSURE POINT CONCENTRATIONS
HUMAN HEALTH - SURFACE WATER
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Constituent Reporting
Units
Number of
Samples
Frequency of
Detection
Minimum
Detected
Concentration
Maximum
Detected
Concentration
Mean Detected
Concentration UCL Selected UCL Exposure Point
Concentration
Exposure Point
Concentration
(mg/L)
Aluminum µg/L 72 70 72.9 1,320 199.5 95% KM (BCA) UCL 237.9 237.9 0.2379
Chromium (VI)µg/L 67 56 0.018 1 0.174 95% KM (Chebyshev) UCL 0.259 0.259 0.000259
Cobalt µg/L 72 72 0.12 3.4 0.518 95% H-UCL 0.58 0.58 0.00058
Manganese µg/L 72 72 26.8 1,040 98.89 95% Chebyshev (Mean, Sd) UCL 174.7 174.7 0.1747
Zinc µg/L 73 28 2.5 22.9 5.132 95% KM (Chebyshev) UCL 5.223 5.223 0.005223
Notes:
---: Calculations were not performed due to lack of samples ND - Not Determined
Mean - Arithmetic mean UCL - 95% Upper Confidence Limit
mg/L - milligrams per liter
µg/L - micrograms per liter
(c) - 0 is defined as a number of samples analyzed or the frequency of detection among samples.
(a)- Mean calculated by ProUCL using the Kaplan-Meier (KM) estimation method for non-detect values: only given for datasets with FOD less than 100% and that met the minimum sample size and FOD requirements for use with ProUCL; see note (b).
(b)- Sample size was greater than or equal to 10 and the number of detected values was greater than or equal to 6, therefore, a 95% UCL was calculated by ProUCL. The UCL shown is the one recommended by ProUCL. If more than one UCL was recommended, the
higher UCL was selected. ProUCL, version 5.0
(d) - The 95% UCL values are calculated using the ProUCL software (V. 5.0; USEPA, 2013a). The ProUCL software performs a goodness-of-fit test that accounts for data sets without any non-detect observations, as well as data sets with non-detect observations. The software then determines
the distribution of the data set for which the EPC is being derived (e.g., normal, lognormal, gamma, or non-discernable), and then calculates a conservative and stable 95% UCL value in accordance with the framework described in “Calculating Upper Confidence Limits for Exposure Point
Concentrations at Hazardous Waste Sites” (USEPA, 2002b). The software includes numerous algorithms for calculating 95% UCL values, and provides a recommended UCL value based on the algorithm that is most applicable to the statistical distribution of the data set. ProUCL will calculate a
95% UCL where there are 3 or more total samples with detected concentrations. Where too few samples or detects are available, the maximum detected concentration is used as the EPC.
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted Prepared by: HEG Checked by: HES
TABLE 4-1
SUMMARY OF EXPOSURE POINT CONCENTRATIONS
ECOLOGICAL - SEDIMENT - BROAD RIVER - EXPOSURE AREA 1
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Aluminum mg/kg 7 7 5,100 37,000 15,281 ------37,000
Barium mg/kg 7 7 23 200 87.17 ------200
Chromium (Total)mg/kg 7 7 11 44 21.36 ------44
Manganese mg/kg 7 7 32 660 268 ------660
Prepared by: TCP Checked by: HEG
Notes:
---: Calculations were not performed due to lack of samples mg/kg - milligrams per kilogram
Mean - Arithmetic mean UCL - 95% Upper Confidence Limit
(b) - 0 is defined as a number of samples analyzed or the frequency of detection among samples.
(a)- Sample size was greater than or equal to 10 and the number of detected values was greater than or equal to 6, therefore, a 95% UCL was calculated by ProUCL. The UCL shown is the one recommended by ProUCL. If more than one
UCL was recommended, the higher UCL was selected. ProUCL, version 5.0
(c) - The 95% UCL values are calculated using the ProUCL software (V. 5.0; USEPA, 2013a). The ProUCL software performs a goodness-of-fit test that accounts for data sets without any non-detect observations, as well as data sets with
non-detect observations. The software then determines the distribution of the data set for which the EPC is being derived (e.g., normal, lognormal, gamma, or non-discernable), and then calculates a conservative and stable 95% UCL
value in accordance with the framework described in “Calculating Upper Confidence Limits for Exposure Point Concentrations at Hazardous Waste Sites” (USEPA, 2002b). The software includes numerous algorithms for calculating 95%
UCL values, and provides a recommended UCL value based on the algorithm that is most applicable to the statistical distribution of the data set. ProUCL will calculate a 95% UCL where there are 3 or more total samples with detected
concentrations. Where too few samples or detects are available, the maximum detected concentration is used as the EPC.
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted
Frequency of
Detection
Number of
Samples
Reporting
UnitsConstituent
Maximum
Detected
Concentration
Minimum
Detected
Concentration
Exposure Point
ConcentrationUCLUCL SelectedMean Detected
Concentration
Page 1 of 2
TABLE 4-2
SUMMARY OF EXPOSURE POINT CONCENTRATIONS
ECOLOGICAL - SURFACE WATER - BROAD RIVER - EXPOSURE AREA 1
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Constituent Reporting
Units
Number of
Samples
Frequency of
Detection
Minimum
Detected
Concentration
Maximum
Detected
Concentration
Mean Detected
Concentration UCL Selected UCL Exposure Point
Concentration
Exposure Point
Concentration
(mg/L)
Aluminum µg/L 32 31 72.9 1,320 254.4 95% KM (Chebyshev) UCL 445.5 445.5 0.4455
Manganese µg/L 32 32 31 1,040 119.7 95% Chebyshev (Mean, Sd) UCL 286.1 286.1 0.2861
Prepared by: TCP Checked by: HEG
Notes:
---: Calculations were not performed due to lack of samples µg/L - micrograms per liter
Mean - Arithmetic mean UCL - 95% Upper Confidence Limit
mg/L - milligrams per liter
(b) - 0 is defined as a number of samples analyzed or the frequency of detection among samples.
(a)- Sample size was greater than or equal to 10 and the number of detected values was greater than or equal to 6, therefore, a 95% UCL was calculated by ProUCL. The UCL shown is the one recommended by ProUCL. If more than one UCL was recommended, the higher UCL was selected.
ProUCL, version 5.0
(c) - The 95% UCL values are calculated using the ProUCL software (V. 5.0; USEPA, 2013a). The ProUCL software performs a goodness-of-fit test that accounts for data sets without any non-detect observations, as well as data sets with non-detect observations. The software then determines
the distribution of the data set for which the EPC is being derived (e.g., normal, lognormal, gamma, or non-discernable), and then calculates a conservative and stable 95% UCL value in accordance with the framework described in “Calculating Upper Confidence Limits for Exposure Point
Concentrations at Hazardous Waste Sites” (USEPA, 2002b). The software includes numerous algorithms for calculating 95% UCL values, and provides a recommended UCL value based on the algorithm that is most applicable to the statistical distribution of the data set. ProUCL will calculate a
95% UCL where there are 3 or more total samples with detected concentrations. Where too few samples or detects are available, the maximum detected concentration is used as the EPC.
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted
Page 2 of 2
TABLE 4-3
SUMMARY OF EXPOSURE POINT CONCENTRATIONS
ECOLOGICAL - SEDIMENT - SUCK CREEK - EXPOSURE AREA 2
BELEWS CREEK STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Barium mg/kg 4 4 7.7 41 21.73 ------41
Prepared by: TCP Checked by: HEG
Notes:
---: Calculations were not performed due to lack of samples mg/kg - milligrams per kilogram
Mean - Arithmetic mean UCL - 95% Upper Confidence Limit
(b) - 0 is defined as a number of samples analyzed or the frequency of detection among samples.
(a)- Sample size was greater than or equal to 10 and the number of detected values was greater than or equal to 6, therefore, a 95% UCL was calculated by ProUCL. The UCL shown is the one recommended by ProUCL. If more than one
UCL was recommended, the higher UCL was selected. ProUCL, version 5.0
(c) - The 95% UCL values are calculated using the ProUCL software (V. 5.0; USEPA, 2013a). The ProUCL software performs a goodness-of-fit test that accounts for data sets without any non-detect observations, as well as data sets with
non-detect observations. The software then determines the distribution of the data set for which the EPC is being derived (e.g., normal, lognormal, gamma, or non-discernable), and then calculates a conservative and stable 95% UCL
value in accordance with the framework described in “Calculating Upper Confidence Limits for Exposure Point Concentrations at Hazardous Waste Sites” (USEPA, 2002b). The software includes numerous algorithms for calculating 95%
UCL values, and provides a recommended UCL value based on the algorithm that is most applicable to the statistical distribution of the data set. ProUCL will calculate a 95% UCL where there are 3 or more total samples with detected
concentrations. Where too few samples or detects are available, the maximum detected concentration is used as the EPC.
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted
Frequency of
Detection
Number of
Samples
Reporting
UnitsConstituent
Maximum
Detected
Concentration
Minimum
Detected
Concentration
Exposure Point
ConcentrationUCLUCL SelectedMean Detected
Concentration
Page 1 of 2
TABLE 4-4
SUMMARY OF EXPOSURE POINT CONCENTRATIONS
ECOLOGICAL - SURFACE WATER - SUCK CREEK - EXPOSURE AREA 2
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Constituent Reporting
Units
Number of
Samples
Frequency of
Detection
Minimum
Detected
Concentration
Maximum
Detected
Concentration
Mean Detected
Concentration UCL Selected UCL Exposure Point
Concentration
Exposure Point
Concentration
(mg/L)
Aluminum µg/L 36 35 77.4 219 147.4 95% KM (t) UCL 155.6 155.6 0.1556
Manganese µg/L 36 36 30 288 88.28 95% Adjusted Gamma UCL 99.73 99.73 0.0997
Prepared by: HEG Checked by: HES
Notes:
---: Calculations were not performed due to lack of samples µg/L - micrograms per liter
Mean - Arithmetic mean UCL - 95% Upper Confidence Limit
mg/L - milligrams per liter
(b) - 0 is defined as a number of samples analyzed or the frequency of detection among samples.
(a)- Sample size was greater than or equal to 10 and the number of detected values was greater than or equal to 6, therefore, a 95% UCL was calculated by ProUCL. The UCL shown is the one recommended by ProUCL. If more than one UCL was recommended, the higher UCL was selected.
ProUCL, version 5.0
(c) - The 95% UCL values are calculated using the ProUCL software (V. 5.0; USEPA, 2013a). The ProUCL software performs a goodness-of-fit test that accounts for data sets without any non-detect observations, as well as data sets with non-detect observations. The software then determines
the distribution of the data set for which the EPC is being derived (e.g., normal, lognormal, gamma, or non-discernable), and then calculates a conservative and stable 95% UCL value in accordance with the framework described in “Calculating Upper Confidence Limits for Exposure Point
Concentrations at Hazardous Waste Sites” (USEPA, 2002b). The software includes numerous algorithms for calculating 95% UCL values, and provides a recommended UCL value based on the algorithm that is most applicable to the statistical distribution of the data set. ProUCL will calculate a
95% UCL where there are 3 or more total samples with detected concentrations. Where too few samples or detects are available, the maximum detected concentration is used as the EPC.
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted
Page 2 of 2
TABLE 4-5
SUMMARY OF EXPOSURE POINT CONCENTRATIONS
ECOLOGICAL - SEDIMENT - BROAD RIVER - EXPOSURE AREA 4
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Barium mg/kg 2 2 27 160 93.5 ------160
Prepared by: TCP Checked by: HEG
Notes:
---: Calculations were not performed due to lack of samples mg/kg - milligrams per kilogram
Mean - Arithmetic mean UCL - 95% Upper Confidence Limit
(b) - 0 is defined as a number of samples analyzed or the frequency of detection among samples.
(a)- Sample size was greater than or equal to 10 and the number of detected values was greater than or equal to 6, therefore, a 95% UCL was calculated by ProUCL. The UCL shown is the one recommended by ProUCL. If more than one
UCL was recommended, the higher UCL was selected. ProUCL, version 5.0
(c) - The 95% UCL values are calculated using the ProUCL software (V. 5.0; USEPA, 2013a). The ProUCL software performs a goodness-of-fit test that accounts for data sets without any non-detect observations, as well as data sets with
non-detect observations. The software then determines the distribution of the data set for which the EPC is being derived (e.g., normal, lognormal, gamma, or non-discernable), and then calculates a conservative and stable 95% UCL
value in accordance with the framework described in “Calculating Upper Confidence Limits for Exposure Point Concentrations at Hazardous Waste Sites” (USEPA, 2002b). The software includes numerous algorithms for calculating 95%
UCL values, and provides a recommended UCL value based on the algorithm that is most applicable to the statistical distribution of the data set. ProUCL will calculate a 95% UCL where there are 3 or more total samples with detected
concentrations. Where too few samples or detects are available, the maximum detected concentration is used as the EPC.
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted
Frequency of
Detection
Number of
Samples
Reporting
UnitsConstituent
Maximum
Detected
Concentration
Minimum
Detected
Concentration
Exposure Point
ConcentrationUCLUCL SelectedMean Detected
Concentration
Page 1 of 2
TABLE 4-6
SUMMARY OF EXPOSURE POINT CONCENTRATIONS
ECOLOGICAL - SURFACE WATER - BROAD RIVER - EXPOSURE AREA 4
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Constituent Reporting
Units
Number of
Samples
Frequency of
Detection
Minimum
Detected
Concentration
Maximum
Detected
Concentration
Mean Detected
Concentration UCL Selected UCL Exposure Point
Concentration
Exposure Point
Concentration
(mg/L)
Aluminum µg/L 4 4 171 299 229.8 ------299 0.299
Prepared by: TCP Checked by: HEG
Notes:
---: Calculations were not performed due to lack of samples µg/L - micrograms per liter
Mean - Arithmetic mean UCL - 95% Upper Confidence Limit
mg/L - milligrams per liter
(b) - 0 is defined as a number of samples analyzed or the frequency of detection among samples.
(a)- Sample size was greater than or equal to 10 and the number of detected values was greater than or equal to 6, therefore, a 95% UCL was calculated by ProUCL. The UCL shown is the one recommended by ProUCL. If more than one UCL was recommended, the higher UCL was selected.
ProUCL, version 5.0
(c) - The 95% UCL values are calculated using the ProUCL software (V. 5.0; USEPA, 2013a). The ProUCL software performs a goodness-of-fit test that accounts for data sets without any non-detect observations, as well as data sets with non-detect observations. The software then determines
the distribution of the data set for which the EPC is being derived (e.g., normal, lognormal, gamma, or non-discernable), and then calculates a conservative and stable 95% UCL value in accordance with the framework described in “Calculating Upper Confidence Limits for Exposure Point
Concentrations at Hazardous Waste Sites” (USEPA, 2002b). The software includes numerous algorithms for calculating 95% UCL values, and provides a recommended UCL value based on the algorithm that is most applicable to the statistical distribution of the data set. ProUCL will calculate a
95% UCL where there are 3 or more total samples with detected concentrations. Where too few samples or detects are available, the maximum detected concentration is used as the EPC.
* Data evaluated includes data from 2015 to 2nd quarter 2018, unless otherwise noted
Page 2 of 2

Risk-Based Concentration Ash Basin-
Groundwater
Non-Cancer Cancer Final Exposure Point
Concentration
(mg/L)(mg/L)(mg/L)(mg/L)
Aluminum 7429-90-5 9.6E+04 nc 9.6E+04 nc 1 0.00001 nc
Antimony 7440-36-0 1.7E+01 nc 1.7E+01 nc 0.001 0.00005 nc
Arsenic 7440-38-2 2.9E+01 4.5E+02 2.9E+01 nc 0.05 0.0017 nc
Barium 7440-39-3 5.0E+03 nc 5.0E+03 nc 0.09 0.00002 nc
Beryllium 7440-41-7 4.8E+02 nc 4.8E+02 nc 0.001 0.000001 nc
Boron 7440-42-8 1.9E+04 nc 1.9E+04 nc 0.28 0.00001 nc
Cadmium 7440-43-9 1.0E+01 nc 1.0E+01 nc 0.0004 0.00003 nc
Chromium, Total 7440-47-3 8.6E+03 nc 8.6E+03 nc 0.01 0.0000009 nc
Chromium (VI)18540-29-9 2.8E+01 7.6E+01 2.8E+01 nc 0.001 0.00003 nc
Cobalt 7440-48-4 3.3E+02 nc 3.3E+02 nc 0.02 0.0001 nc
Lead (a,b)7439-92-1 0.001 NC nc
Lithium 7439-93-2 0.01 NC nc
Manganese 7439-96-5 2.2E+03 nc 2.2E+03 nc 1.52 0.001 nc
Mercury 7439-97-6 5.0E+01 5.0E+01 nc 0.0001 0.000 nc
Molybdenum 7439-98-7 4.8E+02 nc 4.8E+02 nc 0.005 0.00001 nc
Nickel 7440-02-0 1.0E+03 nc 1.0E+03 nc 0.01 0.00001 nc
Selenium 7782-49-2 4.8E+02 nc 4.8E+02 nc 0.003 0.00001 nc
Strontium 7440-24-6 1.9E+05 nc 1.9E+05 nc 0.64 0.000003 nc
Thallium 7440-28-0 0.0002 NA nc
Vanadium 7440-62-2 9.6E+02 nc 9.6E+02 nc 0.003 0.000003 nc
Zinc 7440-66-6 3.1E+04 nc 3.1E+04 nc 0.02 0.000001 nc
Cumulative Risk 0.003 0.00E+00
Prepared by: HHS Checked by: TCP
Notes:
COPC - Chemical of potential concern NA - No toxicity value available; remedial goal not calculated
c - Remedial goal based on cancer risk NC - Not Calculated
nc - Remedial goal based on non-cancer hazard index
(a) USEPA has an action level of 15 ug/L for lead in drinking water (USEPA, 2012b). Refer to Attachment D, Section 2.5 of the Marshall Steam Station CAP (HDR 2015).
(b) Lead was not included in the cumulative risk calculation, as risk for lead is typically evaluted using biokinetic models. Lead concentrations are less than the conservative action level of 15 ug/L.
Groundwater at the site is not used for drinking water.
Exposure Routes Evaluated
Incidental Ingestion Yes
Dermal Contact Yes
Ambient Vapor Inhalation No
Target Hazard Index (per Chemical)1E+00
Target Cancer Risk (per Chemical)1E-04
NA
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
TABLE 5-1
SUMMARY OF ON-SITE GROUNDWATER EPC/RBC COMPARISON
CONSTRUCTION - CONSTRUCTION WORKER (ADULT)
CLIFFSIDE STEAM STATION
Risk Ratio
Non-Cancer Cancer
COPC CAS
Basis
NA
NA
Page 2 of 11
Sediment
Non-Cancer Cancer Final
Exposure
Point
Concentration
(mg/kg)(mg/kg)(mg/kg)(mg/kg)
Aluminum 7429-90-5 1.2E+07 nc 1.2E+07 nc 23,844 0.002 nc
Arsenic 7440-38-2 1.5E+03 1.4E+03 1.4E+03 c 2 0.001 1.29E-03
Cobalt 7440-48-4 3.7E+03 nc 3.7E+03 nc 6.914 0.002 nc
Manganese 7439-96-5 1.7E+06 nc 1.7E+06 nc 438 0.0003 nc
Thallium 7440-28-0 1.2E+02 nc 1.2E+02 nc 0.3 0.002 nc
0.008 1.29E-03
Prepared by: HHS Checked by: TCP
Notes:
COPC - Chemical of potential concern
c - Remedial goal based on cancer risk
nc - remedial goal based on non-cancer hazard index
Exposure Routes Evaluated
Incidental Ingestion Yes
Dermal Contact Yes
Particulate Inhalation No
Ambient Vapor Inhalation No
Target Hazard Index (per Chemical)1E+00
Target Cancer Risk (per Chemical)1E-04
TABLE 5-2
SUMMARY OF OFF-SITE SEDIMENT EPC/RBC COMPARISON
RECREATIONAL SWIMMER - CHILD, ADOLESCENT, and ADULT
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Risk-Based Concentration
Basis
COPC CAS
Non-Cancer Cancer
Risk Ratio
Cumulative Risk
Page 3 of 11
Surface Water
Non-Cancer Cancer Final Exposure Point
Concentration
(mg/L)(mg/L)(mg/L)(mg/L)
Aluminum 7429-90-5 1.1E+03 nc 1.1E+03 nc 0.2 0.0002 nc
Chromium (VI)18540-29-9 3.3E-01 2.0E-02 2.0E-02 c 0.0003 0.0008 1.31E-02
Cobalt 7440-48-4 3.5E-01 nc 3.5E-01 nc 0.001 0.002 nc
Manganese 7439-96-5 4.1E+01 nc 4.1E+01 nc 0.2 0.004 nc
Zinc 7440-66-6 3.4E+02 nc 3.4E+02 nc 0.005 NC nc
Cumulative Risk 0.007 1.31E-02
Prepared by: HHS Checked by: TCP
Notes:
COPC - Chemical of potential concern NA - No toxicity value available; remedial goal not calculated
c - Remedial goal based on cancer risk NC - Not Calculated
Exposure Routes Evaluated
Incidental Ingestion Yes
Dermal Contact Yes
Ambient Vapor Inhalation No
Target Hazard Index (per Chemical)1E+00
Target Cancer Risk (per Chemical)1E-04
TABLE 5-3
SUMMARY OF OFF-SITE SURFACE WATER EPC/RBC COMPARISON
RECREATIONAL SWIMMER - CHILD, ADOLESCENT, and ADULT
CLIFFSIDE STEAM STATION
nc - Remedial goal based on non-cancer hazard index
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Basis
Risk-Based Concentration
COPC CAS
Cancer
Risk Ratio
Non-Cancer
Page 4 of 11
Sediment
Non-Cancer Cancer Final Exposure Point
Concentration
(mg/kg)(mg/kg)(mg/kg)(mg/kg)
Aluminum 7429-90-5 1.2E+07 nc 1.2E+07 nc 23,844 0.002 nc
Arsenic 7440-38-2 1.5E+03 1.4E+03 1.4E+03 c 2 0.001 1.29E-03
Cobalt 7440-48-4 3.7E+03 nc 3.7E+03 nc 6.914 0.002 nc
Manganese 7439-96-5 1.7E+06 nc 1.7E+06 nc 438 0.0003 nc
Thallium 7440-28-0 1.2E+02 nc 1.2E+02 nc 0.3 0.002 nc
Cumulative Risk 0.008 1.29E-03
Prepared by: HHS Checked by: TCP
Notes:
COPC - Chemical of potential concern
c - Remedial goal based on cancer risk
Exposure Routes Evaluated
Incidental Ingestion Yes
Dermal Contact Yes
Particulate Inhalation No
Ambient Vapor Inhalation No
Target Hazard Index (per Chemical)1E+00
Target Cancer Risk (per Chemical)1E-04
nc - Remedial goal based on non-cancer hazard index
TABLE 5-4
SUMMARY OF OFF-SITE SEDIMENT EPC/RBC COMPARISON
RECREATIONAL WADER - CHILD, ADOLESCENT, and ADULT
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Risk-Based Concentration
Basis
COPC CAS
Risk Ratio
Non-Cancer Cancer
Page 5 of 11

Risk-Based Concentration Surface Water
Non-Cancer Cancer Final
Exposure
Point
Concentration
(mg/L)(mg/L)(mg/L)(mg/L)
Aluminum 7429-90-5 1.2E+03 nc 1.2E+03 nc 0.2 0.0002 nc
Chromium (VI)18540-29-9 9.5E-01 8.3E-02 8.3E-02 c 0.0003 0.0003 3.1E-03
Cobalt 7440-48-4 3.6E-01 nc 3.6E-01 nc 0.001 0.002 nc
Manganese 7439-96-5 9.0E+01 nc 9.0E+01 nc 0.2 0.002 nc
Zinc 7440-66-6 3.6E+02 nc 3.6E+02 nc 0.005 0.00001 nc
Cumulative Risk 0.004 3.1E-03
Prepared by: HHS Checked by: TCP
Notes:
COPC - Chemical of potential concern NC - Not Calculated
c - Remedial goal based on cancer risk
Exposure Routes Evaluated
Incidental Ingestion Yes
Dermal Contact Yes
Ambient Vapor Inhalation No
Target Hazard Index (per Chemical)1E+00
Target Cancer Risk (per Chemical)1E-04
Basis
nc - Remedial goal based on non-cancer hazard index
COPC CAS
Cancer
Risk Ratio
Non-Cancer
NA - No toxicity value available; remedial goal not calculated
TABLE 5-5
SUMMARY OF OFF-SITE SURFACE WATER EPC/RBC COMPARISON
RECREATIONAL WADER - CHILD, ADOLESCENT, and ADULT
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Page 6 of 11

Surface Water
Non-Cancer Cancer Final
Exposure
Point
Concentration
(mg/L)(mg/L)(mg/L)(mg/L)
Aluminum 7429-90-5 5.6E+04 nc 5.6E+04 nc 0.2 0.000004 nc
Chromium (VI)18540-29-9 2.1E+00 9.8E-01 9.8E-01 c 0.0003 0.0003 2.6E-04
Cobalt 7440-48-4 4.2E+01 nc 4.2E+01 nc 0.001 0.00001 nc
Manganese 7439-96-5 3.1E+02 nc 3.1E+02 nc 0.2 0.0006 nc
Zinc 7440-66-6 2.8E+04 nc 2.8E+04 nc 0.005 0.0000002 nc
Cumulative Risk 0.0008 2.6E-04
Prepared by: HHS Checked by: TCP
Notes:
COPC - Chemical of potential concern NA - No toxicity value available; remedial goal not calculated
c - Remedial goal based on cancer risk
Exposure Routes Evaluated
Incidental Ingestion No
Dermal Contact Yes
Ambient Vapor Inhalation No
Target Hazard Index (per Chemical)1E+00
Target Cancer Risk (per Chemical)1E-04
Risk-Based Concentration
Basis
nc - Remedial goal based on non-cancer hazard index
NC - Not Calculated
COPC CAS
Cancer
Risk Ratio
Non-Cancer
TABLE 5-6
SUMMARY OF OFF-SITE SURFACE WATER EPC/RBC COMPARISON
RECREATIONAL BOATER - RECREATIONAL BOATER (ADULT)
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Page 7 of 11

Surface Water
Non-Cancer Cancer Final Exposure Point
Concentration
(mg/L)(mg/L)(mg/L)(mg/L)
Aluminum 7429-90-5 5.6E+04 nc 5.6E+04 nc 0.2 0.000004 nc
Chromium (VI)18540-29-9 2.1E+00 9.8E-01 9.8E-01 c 0.0003 0.0003 2.6E-04
Cobalt 7440-48-4 4.2E+01 nc 4.2E+01 nc 0.001 0.00001 nc
Manganese 7439-96-5 3.1E+02 nc 3.1E+02 nc 0.2 0.001 nc
Zinc 7440-66-6 2.8E+04 nc 2.8E+04 nc 0.005 0.0000002 nc
Cumulative Risk 0.001 3E-04
Prepared by: HHS Checked by: TCP
Notes:
COPC - Chemical of potential concern NA - No toxicity value available; remedial goal not calculated
c - Remedial goal based on cancer risk
Exposure Routes Evaluated
Incidental Ingestion No
Dermal Contact Yes
Ambient Vapor Inhalation No
Target Hazard Index (per Chemical)1E+00
Target Cancer Risk (per Chemical)1E-04
Risk-Based Concentration
Basis
nc - Remedial goal based on non-cancer hazard index
NC - Not Calculated
COPC CAS
Cancer
Risk Ratio
Non-Cancer
TABLE 5-7
SUMMARY OF OFF-SITE SURFACE WATER EPC/RBC COMPARISON
RECREATIONAL FISHER - RECREATIONAL FISHER (ADULT)
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Page 8 of 11

Non-Cancer Cancer Final Non-Cancer Cancer Final Non-Cancer Cancer Final
Exposure
Point
Concentration
(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/L)(mg/L)(mg/L)(mg/L)
Aluminum 7429-90-5 4.6E+03 nc 4.6E+03 nc 5.8E+03 nc 5.8E+03 nc 4.6E+03 nc 2.7 1.7E+03 nc 1.7E+03 nc 0.2 0.0001 nc
Chromium (VI)18540-29-9 1.4E+01 6.4E+00 6.4E+00 c 1.7E+01 2.7E+00 2.7E+00 c 1.4E+01 2.7E+00 200 6.9E-02 1.4E-02 1.4E-02 c 0.0003 0.004 0.019
Cobalt 7440-48-4 1.4E+00 nc 1.4E+00 nc 1.7E+00 nc 1.7E+00 nc 1.4E+00 nc 400 3.4E-03 nc 3.4E-03 nc 0.001 0.2 nc
Manganese 7439-96-5 6.4E+02 nc 6.4E+02 nc 8.1E+02 nc 8.1E+02 nc 6.4E+02 nc 2.4 2.7E+02 nc 2.7E+02 nc 0.2 0.001 nc
Zinc 7440-66-6 1.4E+03 nc 1.4E+03 nc 1.7E+03 nc 1.7E+03 nc 1.4E+03 nc 2059 6.7E-01 nc 6.7E-01 nc 0.005 0.01 nc
Cumulative Risk 0.18 1.9E-02
Prepared by: HHS Checked by: TCP
Notes:
COPC - Chemical of potential concern NA - No toxicity value available; remedial goal not calculated BCF - Bioconcentration Factor
c - Remedial goal based on cancer risk NC - Not Calculated Surface water RBC = Fish Tissue RBC / BCF
nc - Remedial goal based on non-cancer hazard index
Exposure Routes Evaluated
Ingestion Yes
Target Hazard Index (per Chemical)1E+00
Target Cancer Risk (per Chemical)1E-04
Lowest
Non-
Cancer
RBC
Value
Lowest
Cancer
RBC
Value
Adult Adolescent (a)
Basis
Surface Water Risk Ratio
Non-Cancer Cancer
TABLE 5-8
SUMMARY OF FISH TISSUE EPC/RBC COMPARISON
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
FISHER - RECREATIONAL (ADULT AND ADOLESCENT)
COPC CAS
Basis
Risk-Based Concentration - Surface Water
Basis
BCF
(unitless)
Risk-Based Concentration - Fish Tissue
Page 9 of 11

Non-Cancer Cancer Final Non-Cancer Cancer Final Non-Cancer Cancer Final Exposure Point
Concentration
(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/kg)(mg/L)(mg/L)(mg/L)(mg/L)
Aluminum 7429-90-5 4.7E+02 nc 4.7E+02 nc 1.5E+02 nc 1.5E+02 nc 1.5E+02 nc 2.7 5.7E+01 nc 5.7E+01 nc 0.2 0.004 nc
Chromium (VI)18540-29-9 1.4E+00 6.6E-01 6.6E-01 c 4.6E-01 3.6E-02 3.6E-02 c 4.6E-01 3.6E-02 200 2.3E-03 1.8E-04 1.8E-04 c 0.0003 0.11 1.44
Cobalt 7440-48-4 1.4E-01 nc 1.4E-01 nc 4.6E-02 nc 4.6E-02 nc 4.6E-02 nc 400 1.1E-04 nc 1.1E-04 nc 0.001 5 nc
Manganese 7439-96-5 6.6E+01 nc 6.6E+01 nc 2.1E+01 nc 2.1E+01 nc 2.1E+01 nc 2.4 8.9E+00 nc 8.9E+00 nc 0.2 0.02 nc
Zinc 7440-66-6 1.4E+02 nc 1.4E+02 nc 4.6E+01 nc 4.6E+01 nc 4.6E+01 nc 2059 2.2E-02 nc 2.2E-02 nc 0.005 0.2 nc
Cumulative Risk 5 1.44E+00
Prepared by: HHS Checked by: TCP
Notes:
COPC - Chemical of potential concern NA - No toxicity value available; remedial goal not calculated BCF - Bioconcentration Factor
c - Remedial goal based on cancer risk NC - Not Calculated Surface water RBC = Fish Tissue RBC / BCF
nc - remedial goal based on non-cancer hazard index
There is no evidence of subsistence fishing occuring in the waterbody evaluated.
Exposure Routes Evaluated
Ingestion Yes
Target Hazard Index (per Chemical)1E+00
Target Cancer Risk (per Chemical)1E-04
Risk-Based Concentration - Fish Tissue
Lowest
Non-
Cancer
RBC
Value
Lowest
Cancer
RBC
Value
Adult Child (a)
Risk Ratio
Non-Cancer Cancer
TABLE 5-9
SUMMARY OF FISH TISSUE EPC/RBC COMPARISON
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
FISHER - SUBSISTENCE (ADULT AND CHILD)
COPC CAS
Basis Basis
Surface WaterRisk-Based Concentration - Surface Water
Basis
BCF
(unitless)
Page 10 of 11
Source Table
(PRG Tables)Media Exposure Pathway Risk Ratio -
Non-cancer
Risk Ratio -
Cancer
TABLE 5-1 Groundwater- On-Site CONSTRUCTION - CONSTRUCTION WORKER (ADULT)0.003 0.00E+00
TABLE 5-2 Sediment- Off-Site OFF-SITE RECREATIONAL SWIMMER - CHILD, ADOLESCENT, and ADULT 0.008 1.3E-03
TABLE 5-3 Surface Water- Off-Site OFF-SITE RECREATIONAL SWIMMER - CHILD, ADOLESCENT, and ADULT 0.007 1.3E-02
TABLE 5-4 Sediment- Off-Site OFF-SITE RECREATIONAL WADER - CHILD, ADOLESCENT, and ADULT 0.008 1.3E-03
TABLE 5-5 Surface Water- Off-Site OFF-SITE RECREATIONAL WADER - CHILD, ADOLESCENT, and ADULT 0.004 3.1E-03
TABLE 5-6 Surface Water- Off-Site OFF-SITE RECREATIONAL BOATER - OFF-SITE RECREATIONAL BOATER (ADULT)0.0008 2.6E-04
TABLE 5-7 Surface Water- Off-Site OFF-SITE RECREATIONAL FISHER (ADULT)0.0008 2.6E-04
TABLE 5-8 Biota (fish)- Off-Site OFF-SITE FISHER - RECREATIONAL (ADULT AND ADOLESCENT)0.2 1.9E-02
TABLE 5-9 Biota (fish)- Off-Site OFF-SITE FISHER - SUBSISTENCE (ADULT AND ADOLESCENT)5 1.4E+00
Prepared by: HHS Checked by: TCP
TABLE 5-10
SUMMARY OF EXPOSURE POINT CONCENTRATION COMPARISON TO RISK-BASED CONCENTRATION
CLIFFSIDE STEAM STATION
DUKE ENERGY CAROLINAS, LLC, MOORESBORO, NC
Page 11 of 11
Plants Mammal/Terr.
Vertebrates Fish Invertebrates Birds Soil
BW IRF IRW PF AM AF AI AB SF HR SUF
kg kg/kg BW/day L/kg BW/day %%%%%%hectares unitless
Meadow Volea 0.033 0.33 0.21 97.6%0%0%0%0%2.4%0.027 1
Muskratb 1.17 0.3 0.97 99.3%0%0%0%0%0.7%0.13 1
Mallard Duckc 1.134 0.068 0.057 48.3%0%0%48.3%0%3.3%435 1
American Robind 0.08 0.129 0.14 40%0%0%58%0%2%0.42 1
Red-Tailed Hawke 1.06 0.18 0.058 0%91.5%0%0%8.5%0%876 1
Bald Eaglef 3.75 0.12 0.058 0%28%58%0%13.5%0.5%2199 1
Red Foxg 4.54 0.16 0.085 6%89%0%2%0%3%1226 1
River Otterh 6.76 0.19 0.081 0%0%100%0%0%0%348 1
Great Blue Heroni 2.229 0.18 0.045 0%0%90%9.5%0%0.5%227 1
NOTES:
SUF - Seasonal Use Factor
PF - Plant Matter Ingestion Percentage
AM - Mammal/Terrestrial Vertebrate ingestion percentage
AF - Fish Ingestion Percentage
AB - Bird Ingestion Percentage
SF - Soil Ingestion Percentage
f BW, PF, AF, AM, AB, HR from USEPA 1993 (sections 2-91 and 2-97); IRF from Nagy 2001
g BW, PF, AF, AI, HR from USEPA 1993 (sections 2-224 and 2-225); SF from Beyer et al. 1994
h BW, IRw, AF, HR from USEPA 1993 (sections 2-264 and 2-266); SF from Sample and Suter 1994; IRF from Nagy 2001
i BW, PF, AF, AI, HR from USEPA 1993 (sections 2-8 and 2-9); SF from Sample and Suter 1994; IRF from Nagy 2001
j Seasonal Use Factor is set to a default of 1 to be overly conservative and protective of ecological receptors.
Table 1
Seasonal Use
Factorj
Home
RangeBody Weight Food Ingestion Rate Water Ingestion
Rate
Dietary Composition
Algorithm ID
Units
Parameter
Exposure Parameters for Ecological Receptors
Ecological Exposure Area 1
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Ecological ReceptorsBW - Body Weight
kg - Kilograms
IR - Ingestion Rate
HR - Home Range
HERBIVORE
OMNIVORE
CARNIVORE
PISCIVORE
kg/kg BW/day - Kilograms Food per Kilograms Body Weight per Day
L/kg BW/day - Liters Water per Kilogram Body Weight per Day
a BW, IRf, IRw, PF, HR from USEPA 1993 (sections 2-328 and 2-329); SF from Sample and Suter 1994
b BW, IRf, IRw, PF, HR from USEPA 1993 (sections 2-340 and 2-341); SF from TechLaw Inc. 2013; IRF from Nagy 2001
c BW, PF, AI, HR from USEPA 1993 (sections 2-43 and 2-45); SF from Beyer et al. 1994; IRF from Nagy 2001
d BW, PF, AI, HR from USEPA 1993 (sections 2-197 and 2-198); SF from Sample and Suter 1994; IRF from Nagy 2001
e BW, PF, AM, AB, IRF, HR from USEPA 1993 (sections 2-82 and 2-83)
Table 2
Toxicity Reference Values for Ecological Receptors
Ecological Exposure Area 1
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Mallard Duck
(mg/kg/day)
Great Blue
Heron
(mg/kg/day)
Bald Eagle
(mg/kg/day)
Muskrat
(mg/kg/day)
River Otter
(mg/kg/day)
American
Robin
(mg/kg/day)
Red-Tailed
Hawk
(mg/kg/day)
Meadow Vole
(mg/kg/day)
Red Fox
(mg/kg/day)
Aluminuma 110 110 110 1.93 1.93 110 110 1.93 1.93
Antimonya NA NA NA 0.059 0.059 NA NA 0.059 0.059
Arsenicb 2.24 2.24 2.24 1.04 1.04 2.24 2.24 1.04 1.04
Bariumc 20.8 20.8 20.8 51.8 51.8 20.8 20.8 51.8 51.8
Berylliuma NA NA NA 0.532 0.532 NA NA 0.532 0.532
Borona, b 28.8 28.8 28.8 28 28 28.8 28.8 28 28
Cadmiuma 1.47 1.47 1.47 0.77 0.77 1.47 1.47 0.77 0.77
Calcium EN EN EN EN EN EN EN EN EN
Chromium, Totald 1 1 1 2740 2740 1 1 2740 2740
Chromium VI (hexavalent)a NA NA NA 9.24 9.24 NA NA 9.24 9.24
Chromium IIIa 2.66 2.66 2.66 2.4 2.4 2.66 2.66 2.4 2.4
Cobalta 7.61 7.61 7.61 7.33 7.33 7.61 7.61 7.33 7.33
Coppera 4.05 4.05 4.05 5.6 5.6 4.05 4.05 5.6 5.6
Iron EN EN EN EN EN EN EN EN EN
Leadb 1.63 1.63 1.63 4.7 4.7 1.63 1.63 4.7 4.7
Magnesium EN EN EN EN EN EN EN EN EN
Manganesea 179 179 179 51.5 51.5 179 179 51.5 51.5
Mercurye 3.25 3.25 3.25 1.01 1.01 3.25 3.25 1.01 1.01
Molybdenuma, d 3.53 3.53 3.53 0.26 0.26 3.53 3.53 0.26 0.26
Nickela 6.71 6.71 6.71 1.7 1.7 6.71 6.71 1.7 1.7
Potassium EN EN EN EN EN EN EN EN EN
Seleniuma 0.29 0.29 0.29 0.143 0.143 0.29 0.29 0.143 0.143
Sodium EN EN EN EN EN EN EN EN EN
Strontiuma, d NA NA NA 263 263 NA NA 263 263
Thalliuma NA NA NA 0.015 0.015 NA NA 0.015 0.015
Titanium NA NA NA NA NA NA NA NA NA
Vanadiuma 0.344 0.344 0.344 4.16 4.16 0.344 0.344 4.16 4.16
Zinca 66.1 66.1 66.1 75.4 75.4 66.1 66.1 75.4 75.4
Nitrated NA NA NA 507 507 NA NA 507 507
Analyte
Aquatic
TRVs (NOAEL)
Terrestrial
Mallard Duck
(mg/kg/day)
Great Blue
Heron
(mg/kg/day)
Bald Eagle
(mg/kg/day)
Muskrat
(mg/kg/day)
River Otter
(mg/kg/day)
American
Robin
(mg/kg/day)
Red-Tailed
Hawk
(mg/kg/day)
Meadow Vole
(mg/kg/day)
Red Fox
(mg/kg/day)
Aluminuma 1100 1100 1100 19.3 19.3 1100 1100 19.3 19.3
Antimonya NA NA NA 0.59 0.59 NA NA 0.59 0.59
Arsenicb 40.3 40.3 40.3 1.66 1.66 40.3 40.3 1.66 1.66
Bariumc 41.7 41.7 41.7 75 75 41.7 41.7 75 75
Berylliuma NA NA NA 6.6 6.6 NA NA 6.6 6.6
Borona, b 100 100 100 93.6 93.6 100 100 93.6 93.6
Cadmiuma 2.37 2.37 2.37 10 10 2.37 2.37 10 10
Calcium EN EN EN EN EN EN EN EN EN
Chromium, Totald 5 5 5 27400 27400 5 5 27400 27400
Chromium VI (hexavalent)a NA NA NA 40 40 NA NA 40 40
Chromium IIIa 2.66 2.66 2.66 9.625 9.625 2.66 2.66 9.625 9.625
Cobalta 7.8 7.8 7.8 10.9 10.9 7.8 7.8 10.9 10.9
Coppera 12.1 12.1 12.1 9.34 9.34 12.1 12.1 9.34 9.34
Iron EN EN EN EN EN EN EN EN EN
Leadb 3.26 3.26 3.26 8.9 8.9 3.26 3.26 8.9 8.9
Magnesium EN EN EN EN EN EN EN EN EN
Manganesea 348 348 348 71 71 348 348 71 71
Mercurye 0.37 0.37 0.37 0.16 0.16 0.37 0.37 0.16 0.16
Molybdenuma, d 35.3 35.3 35.3 2.6 2.6 35.3 35.3 2.6 2.6
Nickela 11.5 11.5 11.5 3.4 3.4 11.5 11.5 3.4 3.4
Potassium EN EN EN EN EN EN EN EN EN
Seleniuma 0.579 0.579 0.579 0.215 0.215 0.579 0.579 0.215 0.215
Sodium EN EN EN EN EN EN EN EN EN
Strontiuma, d NA NA NA 2630 2630 NA NA 2630 2630
Thalliuma NA NA NA 0.075 0.075 NA NA 0.075 0.075
Vanadiuma 0.688 0.688 0.688 8.31 8.31 0.688 0.688 8.31 8.31
Zinca 66.5 66.5 66.5 75.9 75.9 66.5 66.5 75.9 75.9
Nitrated NA NA NA 1130 1130 NA NA 1130 1130
TRV - Toxicity Reference Value
Table 2 (Cont.)
NOTES:
NOAEL - No Observed Adverse Effects Level
LOAEL - Lowest Observed Effects Level
EN - Essential nutrient
NA - Not available
b USEPA 2005 EcoSSL
c Only a single paper (Johnson et al., 1960) with data on the toxicity of barium hydroxide to one avian species (chicken) was identified by USEPA (2005); therefore, an avian TRV could not
be derived and an Eco-SSL could not be calculated for avian wildlife (calculation requires a minimum of three results for two test species). Johnson et al. (1960) reports a subchronic
NOAEL of 208.26 mg/kg/d. The NOAEL was multiplied by an uncertainty factor of 0.1 to derive a very conservative TRV of 20.8 mg/kg/d.
d Sample et al. 1996
a CH2M Hill. 2014. Tier 2 Risk-Based Soil Concentrations Protective of Ecological Receptors at the Hanford Site. CHPRC-01311. Revision 2. July.
Http://pdw.hanford.gov/arpir/pdf.cfm?accession=0088115
Analyte Aquatic
TRVs (LOAEL)
Terrestrial
Table 3
Exposure Area and Area Use Factors for Ecological Receptors
Ecological Exposure Area 1
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Mallard
Duck
Great Blue
Heron Muskrat River
Otter
Bald
Eagle
American
Robin
Red-Tailed
Hawk
Meadow
Vole Red Fox
Ecological Exposure Area 1 6.3 1.45%2.78%100%1.81%0.29%100%0.719%100%0.51%
NOTES:
Area Use Factor (AUF)
Exposure Point Exposure Areaa
(hectares)
a Exposure Area 1 is north of the Inactive Ash Basins and Active Ash Basin. The area includes aquatic habitats in Broad River and Suck Creek.
Table 4
EPCs for Use in the Risk Assessment
Ecological Exposure Area 1
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
COPC CASRN
Sediment EPC Used in
Risk Assessmentc
(mg/kg)
Surface Water EPC Used
in Risk Assessment
(mg/L)
Aluminum 7429-90-5 37,000 0.4455
Barium 7440-39-3 200
Chromium, Total 7440-47-3 44
Manganese 7439-96-5 660 0.2861
Aquatic EPCsa, b
a Surface water EPCs are based on 95% UCLs where there is adequate sample size to calculate
UCLs. Sediment EPCs are based on maximum values due to insufficient sample size.
b Surface water and sediment are used to estimate risk to aquatic receptors.
c Analysis of solids (i.e., soil and sediment) was reported as dry weight.
NOTES:
COPC - Constituent of Potential Concern
CASRN - Chemical Abstracts Service Registration Number
EPC - Exposure Point Concentration
Table 5
Calculation of Average Daily Doses for Mallard Duck
Ecological Exposure Area 1
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCp EPCi NIRw ADDW Pf NIRf NIRp ADDp Af NIRa ADDa Sf NIRs ADDs BF ADDt SUF AUF ADDtot
Analyte COPEC in Water
(mg/L)
COPEC in Solid
(mg/kg)
Slope, or Plant
Uptake (BAF)Intercept
Estimated1
Concentration
in Vegetation
(mg/kg dry)
Slope, or
Invertebrate
Uptake (BAF)
Intercept
Estimated2
Concentration
in
Invertebrates
(mg/kg dry)
Water
Ingestion Rate
(L/kg BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Plant Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg BW/day)
Plant Ingestion
Rate, Dry
(kg/kg BW/day)
Unadjusted
Average Daily
Dose Plant
(mg/kg/day)
Fraction Diet
Invertebrates
(percent)
Invertebrates
Ingestion Rate
(kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose
Invertebrates
(mg/kg/day)
Fraction Diet
Soil (percent)
Soil Ingestion3
Rate (kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose Soil
(mg/kg/day)
Bioavailability3
(percent)
Omnivore
Intake
(mg/kg/day)
Seasonal Use
Factor
(unitless)
Area Use Factor
(Exposure
Area/Home
Range)
Adjusted Total
Omnivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.45 37,000 0.0008 29.6 1 37000 0.057 0.025 48%0.068 0.0049 0.145827 48%0.007 267.3502 3.3%0.00029 10.79364 100%278.32 1 0.01 4.030769
Barium 200 0.03 6 1 200 0.057 0 48%0.068 0.0049 0.02956 48%0.007 1.4451 3.3%0.00029 0.05834 100%1.533 1 0.01 0.022203
Chromium, Total 44 0.0015 0.066 0.1 4.4 0.057 0 48%0.068 0.0049 0.000325 48%0.007 0.0318 3.3%0.00029 0.01284 100%0.04495 1 0.01 0.000651
Manganese 0.29 660 0.05 33 0.682 -0.809 37.29 0.057 0.016 48%0.068 0.0049 0.162578 48%0.007 0.2694 3.3%0.00029 0.19254 100%0.64 1 0.01 0.009281
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
AVERAGE DAILY DOSE VIA:
WATER
1 Bechtel Jacobs Company 1998a; Baes et al. 1984 (Mo); Environmental Restoration Division - Manual ERD-AG-003 1999; default value of 1 is used for constituents for which a BAF could not be found.
2 Bechtel Jacobs Company 1998b, Table 2, median BAFs for sediment to benthic invertebrates for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn; Sample et al. 1998b (earthworms) for Mn; default value of 1 is used for constituents for which a BAF could not be found.
PLANTS/VEGETATION INVERTEBRATES SOIL
3 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
Table 6
Calculation of Average Daily Doses for Great Blue Heron
Ecological Exposure Area 1
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCfish EPCi NIRw ADDw Af NIRf NIRa ADDa Af NIRa ADDa BF ADDt SUF AUF ADDtot
Analyte COPEC in
Water (mg/L)
COPEC in Solid
(mg/kg)
Fish Uptake
(BCF)
Estimated1
Concentration
in Fish (mg/kg)
Slope, or
Invertebrate
Uptake (BAF)
Intercept
Estimated2
Concentration
in
Invertebrates
(mg/kg dry)
Water
Ingestion Rate
(L/kg BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Animal Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg
BW/day)
Fish Ingestion
Rate (kg/kg
BW/day)
Unadjusted
Average Daily
Dose
(mg/kg/day)
Fraction Diet
Invertebrates
(percent)
Invertebrates
Ingestion Rate
(kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose
Invertebrates
(mg/kg/day)
Bioavailability3
(percent)
Piscivore
Intake
(mg/kg/day)
Seasonal Use
Factor
(unitless)
Area Use
Factor
(Exposure
Area/Home
Range)
Adjusted Total
Piscivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.446 37,000 0.1 0.04 1 0.45 0.045 0.02 90%0.18 0.162 0.007 10%0.004 0.0017 100%0.03 1 0.028 0.001
Barium 200 4 0 1 0 0.045 0 90%0.18 0.162 0 10%0.004 0 100%0 1 0.028 0
Chromium, Total 44 200 0 0.1 0 0.045 0 90%0.18 0.162 0 10%0.004 0 100%0 1 0.028 0
Manganese 0.286 660 400 114.44 0.682 -0.809 0.19 0.045 0.013 90%0.18 0.162 18.539 10%0.004 0.0007 100%18.55 1 0.028 0.51
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
WATER FISH INVERTEBRATES
AVERAGE DAILY DOSE VIA:
1 Al (Voigt et al. 2015), mean of fish tissue BAFs; Cu (USEPA 1980); Environmental Restoration Division - Manual ERD-AG-003 1999.
3 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
2 Bechtel Jacobs Company 1998b, Table 2, median BAFs for sediment to benthic invertebrates for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn; Sample et al. 1998b (earthworms) for Mn; default value of 1 is used for constituents for which a BAF could not be found.
Table 7
Calculation of Average Daily Doses for Muskrat
Ecological Exposure Area 1
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCp NIRW ADDw Pf NIRf NIRp ADDp Sf NIRs ADDs BF ADDt SUF AUF ADDtot
Analyte COPEC in Water
(mg/L)
COPEC in Solid
(mg/kg)
Slope, or Plant
Uptake (BAF)Intercept
Estimated1
Concentration
in Vegetation
(mg/kg dry)
Water Ingestion
Rate (L/kg
BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Plant Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg BW/day)
Plant Ingestion
Rate, Dry
(kg/kg/day)
Unadjusted
Average Daily
Dose Plant
(mg/kg/day)
Fraction Diet
Soil (percent)
Soil Ingestion
Rate (kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose Soil
(mg/kg/day)
Bioavailability2
(percent)
Herbivore
Intake
(mg/kg/day)
Seasonal Use
Factor (unitless)
Area Use Factor
(Exposure
Area/Home
Range)
Adjusted Total
Herbivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.4 37,000 0.0008 29.6 0.97 0.43 99%0.3 0.045 1.32268 1%0.000273 1.31313 100%3.07 1 1 3.07
Barium 200 0.03 6 0.97 0 99%0.3 0.045 0.26811 1%0.000273 0.0071 100%0.28 1 1 0.28
Chromium, Total 44 0.0015 0.066 0.97 0 99%0.3 0.045 0.00295 1%0.000273 0.00156 100%0 1 1 0
Manganese 0.3 660 0.05 33 0.97 0.28 99%0.3 0.045 1.47461 1%0.000273 0.02342 100%1.78 1 1 1.78
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
AVERAGE DAILY DOSE VIA:
WATER PLANTS / VEGETATION SOIL
1 Bechtel Jacobs Company 1998a; Baes et al. 1984 (Mo); Environmental Restoration Division - Manual ERD-AG-003 1999; default value of 1 is used for constituents for which a BAF could not be found.
2 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
Table 8
Calculation of Average Daily Doses for River Otter
Ecological Exposure Area 1
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCPREY NIRw ADDw Pf NIRf NIRa ADDa BF ADDt SUF AUF ADDtot
Analyte
COPEC in
Water (mg/L)
COPEC in Solid
(mg/kg)
Fish Uptake
(BCF)
Estimated1
Concentration
in Fish (mg/kg)
Water
Ingestion Rate
(L/kg BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Animal Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg BW/day)
Fish Ingestion
Rate (kg/kg
BW/day)
Unadjusted
Average Daily
Dose
(mg/kg/day)
Bioavailability2
(percent)
Piscivore
Intake
(mg/kg/day)
Seasonal Use
Factor
(unitless)
Area Use
Factor
(Exposure
Area/Home
Range)
Adjusted Total
Piscivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.4 37,000 0.1 0.04 0.081 0.036 100%0.19 0.19 0.0085 100%0.045 1 0.018 0.000807
Barium 200 4 0 0.081 0 100%0.19 0.19 0 100%0 1 0.018 0
Chromium, Total 44 200 0 0.081 0 100%0.19 0.19 0 100%0 1 0.018 0
Manganese 0.3 660 400 114.44 0.081 0.023 100%0.19 0.19 21.74 100%21.767 1 0.018 0.394054
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
AVERAGE DAILY DOSE VIA:
DRINKING WATER FISH
1 Al (Voigt et al. 2015), mean of fish tissue BAFs; Cu (USEPA 1980); Environmental Restoration Division - Manual ERD-AG-003 1999.
2 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
Table 9
Hazard Quotients for COPCs - Aquatic Receptors
Ecological Exposure Area 1
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Mallard Duck Great Blue Heron Muskrat River Otter
Aluminum 3.66E-02 7.30E-06 1.59E+00 4.18E-04
Barium 1.07E-03 0.00E+00 5.31E-03 0.00E+00
Chromium, Total 6.51E-04 0.00E+00 1.65E-06 0.00E+00
Manganese 5.19E-05 2.88E-03 3.45E-02 7.65E-03
Mallard Duck Great Blue Heron Muskrat River Otter
Aluminum 3.66E-03 7.30E-07 1.59E-01 4.18E-05
Barium 5.32E-04 0.00E+00 3.67E-03 0.00E+00
Chromium, Total 1.30E-04 0.00E+00 1.65E-07 0.00E+00
Manganese 2.67E-05 1.48E-03 2.50E-02 5.55E-03

Hazard Quotients greater than or equal to 1 are highlighted in gray and in boldface.
Wildlife Receptor Hazard Quotient Estimated using the 'No Observed Adverse Effects Level'
AquaticAnalyte
Analyte
Wildlife Receptor Hazard Quotient Estimated using the 'Lowest Observed Adverse Effects
Aquatic
NOTES:
NM - Not measured due to lack of a Toxicity Reference Value
Plants Mammal/Terr.
Vertebrates Fish Invertebrates Birds Soil
BW IRF IRW PF AM AF AI AB SF HR SUF
kg kg/kg BW/day L/kg BW/day %%%%%%hectares unitless
Meadow Volea 0.033 0.33 0.21 97.6%0%0%0%0%2.4%0.027 1
Muskratb 1.17 0.3 0.97 99.3%0%0%0%0%0.7%0.13 1
Mallard Duckc 1.134 0.068 0.057 48.3%0%0%48.3%0%3.3%435 1
American Robind 0.08 0.129 0.14 40%0%0%58%0%2%0.42 1
Red-Tailed Hawke 1.06 0.18 0.058 0%91.5%0%0%8.5%0%876 1
Bald Eaglef 3.75 0.12 0.058 0%28%58%0%13.5%0.5%2199 1
Red Foxg 4.54 0.16 0.085 6%89%0%2%0%3%1226 1
River Otterh 6.76 0.19 0.081 0%0%100%0%0%0%348 1
Great Blue Heroni 2.229 0.18 0.045 0%0%90%9.5%0%0.5%227 1
NOTES:
SUF - Seasonal Use Factor
PF - Plant Matter Ingestion Percentage
AM - Mammal/Terrestrial Vertebrate ingestion percentage
AF - Fish Ingestion Percentage
AB - Bird Ingestion Percentage
SF - Soil Ingestion Percentage
f BW, PF, AF, AM, AB, HR from USEPA 1993 (sections 2-91 and 2-97); IRF from Nagy 2001
g BW, PF, AF, AI, HR from USEPA 1993 (sections 2-224 and 2-225); SF from Beyer et al. 1994
h BW, IRw, AF, HR from USEPA 1993 (sections 2-264 and 2-266); SF from Sample and Suter 1994; IRF from Nagy 2001
i BW, PF, AF, AI, HR from USEPA 1993 (sections 2-8 and 2-9); SF from Sample and Suter 1994; IRF from Nagy 2001
j Seasonal Use Factor is set to a default of 1 to be overly conservative and protective of ecological receptors.
Table 1
Seasonal Use
Factorj
Home
RangeBody Weight Food Ingestion Rate Water Ingestion
Rate
Dietary Composition
Algorithm ID
Units
Parameter
Exposure Parameters for Ecological Receptors
Ecological Exposure Area 2
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Ecological ReceptorsBW - Body Weight
kg - Kilograms
IR - Ingestion Rate
HR - Home Range
HERBIVORE
OMNIVORE
CARNIVORE
PISCIVORE
kg/kg BW/day - Kilograms Food per Kilograms Body Weight per Day
L/kg BW/day - Liters Water per Kilogram Body Weight per Day
a BW, IRf, IRw, PF, HR from USEPA 1993 (sections 2-328 and 2-329); SF from Sample and Suter 1994
b BW, IRf, IRw, PF, HR from USEPA 1993 (sections 2-340 and 2-341); SF from TechLaw Inc. 2013; IRF from Nagy 2001
c BW, PF, AI, HR from USEPA 1993 (sections 2-43 and 2-45); SF from Beyer et al. 1994; IRF from Nagy 2001
d BW, PF, AI, HR from USEPA 1993 (sections 2-197 and 2-198); SF from Sample and Suter 1994; IRF from Nagy 2001
e BW, PF, AM, AB, IRF, HR from USEPA 1993 (sections 2-82 and 2-83)
Table 2
Toxicity Reference Values for Ecological Receptors
Ecological Exposure Area 2
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Mallard Duck
(mg/kg/day)
Great Blue
Heron
(mg/kg/day)
Bald Eagle
(mg/kg/day)
Muskrat
(mg/kg/day)
River Otter
(mg/kg/day)
American
Robin
(mg/kg/day)
Red-Tailed
Hawk
(mg/kg/day)
Meadow Vole
(mg/kg/day)
Red Fox
(mg/kg/day)
Aluminuma 110 110 110 1.93 1.93 110 110 1.93 1.93
Antimonya NA NA NA 0.059 0.059 NA NA 0.059 0.059
Arsenicb 2.24 2.24 2.24 1.04 1.04 2.24 2.24 1.04 1.04
Bariumc 20.8 20.8 20.8 51.8 51.8 20.8 20.8 51.8 51.8
Berylliuma NA NA NA 0.532 0.532 NA NA 0.532 0.532
Borona, b 28.8 28.8 28.8 28 28 28.8 28.8 28 28
Cadmiuma 1.47 1.47 1.47 0.77 0.77 1.47 1.47 0.77 0.77
Calcium EN EN EN EN EN EN EN EN EN
Chromium, Totald 1 1 1 2740 2740 1 1 2740 2740
Chromium VI (hexavalent)a NA NA NA 9.24 9.24 NA NA 9.24 9.24
Chromium IIIa 2.66 2.66 2.66 2.4 2.4 2.66 2.66 2.4 2.4
Cobalta 7.61 7.61 7.61 7.33 7.33 7.61 7.61 7.33 7.33
Coppera 4.05 4.05 4.05 5.6 5.6 4.05 4.05 5.6 5.6
Iron EN EN EN EN EN EN EN EN EN
Leadb 1.63 1.63 1.63 4.7 4.7 1.63 1.63 4.7 4.7
Magnesium EN EN EN EN EN EN EN EN EN
Manganesea 179 179 179 51.5 51.5 179 179 51.5 51.5
Mercurye 3.25 3.25 3.25 1.01 1.01 3.25 3.25 1.01 1.01
Molybdenuma, d 3.53 3.53 3.53 0.26 0.26 3.53 3.53 0.26 0.26
Nickela 6.71 6.71 6.71 1.7 1.7 6.71 6.71 1.7 1.7
Potassium EN EN EN EN EN EN EN EN EN
Seleniuma 0.29 0.29 0.29 0.143 0.143 0.29 0.29 0.143 0.143
Sodium EN EN EN EN EN EN EN EN EN
Strontiuma, d NA NA NA 263 263 NA NA 263 263
Thalliuma NA NA NA 0.015 0.015 NA NA 0.015 0.015
Titanium NA NA NA NA NA NA NA NA NA
Vanadiuma 0.344 0.344 0.344 4.16 4.16 0.344 0.344 4.16 4.16
Zinca 66.1 66.1 66.1 75.4 75.4 66.1 66.1 75.4 75.4
Nitrated NA NA NA 507 507 NA NA 507 507
Analyte
Aquatic
TRVs (NOAEL)
Terrestrial
Mallard Duck
(mg/kg/day)
Great Blue
Heron
(mg/kg/day)
Bald Eagle
(mg/kg/day)
Muskrat
(mg/kg/day)
River Otter
(mg/kg/day)
American
Robin
(mg/kg/day)
Red-Tailed
Hawk
(mg/kg/day)
Meadow Vole
(mg/kg/day)
Red Fox
(mg/kg/day)
Aluminuma 1100 1100 1100 19.3 19.3 1100 1100 19.3 19.3
Antimonya NA NA NA 0.59 0.59 NA NA 0.59 0.59
Arsenicb 40.3 40.3 40.3 1.66 1.66 40.3 40.3 1.66 1.66
Bariumc 41.7 41.7 41.7 75 75 41.7 41.7 75 75
Berylliuma NA NA NA 6.6 6.6 NA NA 6.6 6.6
Borona, b 100 100 100 93.6 93.6 100 100 93.6 93.6
Cadmiuma 2.37 2.37 2.37 10 10 2.37 2.37 10 10
Calcium EN EN EN EN EN EN EN EN EN
Chromium, Totald 5 5 5 27400 27400 5 5 27400 27400
Chromium VI (hexavalent)a NA NA NA 40 40 NA NA 40 40
Chromium IIIa 2.66 2.66 2.66 9.625 9.625 2.66 2.66 9.625 9.625
Cobalta 7.8 7.8 7.8 10.9 10.9 7.8 7.8 10.9 10.9
Coppera 12.1 12.1 12.1 9.34 9.34 12.1 12.1 9.34 9.34
Iron EN EN EN EN EN EN EN EN EN
Leadb 3.26 3.26 3.26 8.9 8.9 3.26 3.26 8.9 8.9
Magnesium EN EN EN EN EN EN EN EN EN
Manganesea 348 348 348 71 71 348 348 71 71
Mercurye 0.37 0.37 0.37 0.16 0.16 0.37 0.37 0.16 0.16
Molybdenuma, d 35.3 35.3 35.3 2.6 2.6 35.3 35.3 2.6 2.6
Nickela 11.5 11.5 11.5 3.4 3.4 11.5 11.5 3.4 3.4
Potassium EN EN EN EN EN EN EN EN EN
Seleniuma 0.579 0.579 0.579 0.215 0.215 0.579 0.579 0.215 0.215
Sodium EN EN EN EN EN EN EN EN EN
Strontiuma, d NA NA NA 2630 2630 NA NA 2630 2630
Thalliuma NA NA NA 0.075 0.075 NA NA 0.075 0.075
Vanadiuma 0.688 0.688 0.688 8.31 8.31 0.688 0.688 8.31 8.31
Zinca 66.5 66.5 66.5 75.9 75.9 66.5 66.5 75.9 75.9
Nitrated NA NA NA 1130 1130 NA NA 1130 1130
TRV - Toxicity Reference Value
Table 2 (Cont.)
NOTES:
NOAEL - No Observed Adverse Effects Level
LOAEL - Lowest Observed Effects Level
EN - Essential nutrient
NA - Not available
b USEPA 2005 EcoSSL
c Only a single paper (Johnson et al., 1960) with data on the toxicity of barium hydroxide to one avian species (chicken) was identified by USEPA (2005); therefore, an avian TRV could not
be derived and an Eco-SSL could not be calculated for avian wildlife (calculation requires a minimum of three results for two test species). Johnson et al. (1960) reports a subchronic
NOAEL of 208.26 mg/kg/d. The NOAEL was multiplied by an uncertainty factor of 0.1 to derive a very conservative TRV of 20.8 mg/kg/d.
d Sample et al. 1996
a CH2M Hill. 2014. Tier 2 Risk-Based Soil Concentrations Protective of Ecological Receptors at the Hanford Site. CHPRC-01311. Revision 2. July.
Http://pdw.hanford.gov/arpir/pdf.cfm?accession=0088115
Analyte Aquatic
TRVs (LOAEL)
Terrestrial
Table 3
Exposure Area and Area Use Factors for Ecological Receptors
Ecological Exposure Area 2
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Mallard
Duck
Great Blue
Heron Muskrat River
Otter
Bald
Eagle
American
Robin
Red-Tailed
Hawk
Meadow
Vole Red Fox
Ecological Exposure Area 2 4.2 0.97%1.85%100%1.21%0.19%100%0.479%100%0.34%
NOTES:
Area Use Factor (AUF)
Exposure Point Exposure Areaa
(hectares)
a Exposure Area 2 is west of the Active Ash Basin and Southeast of the Inactive Ash Basins. The area includes aquatic habitat in Suck Creek.
Table 4
EPCs for Use in the Risk Assessment
Ecological Exposure Area 2
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
COPC CASRN
Sediment EPC Used in
Risk Assessmentc
(mg/kg)
Surface Water EPC Used
in Risk Assessment
(mg/L)
Aluminum 7429-90-5 0.1556
Barium 7440-39-3 41
Manganese 7439-96-5 0.0997
Aquatic EPCsa, b
a EPCs for surface water are based on 95% UCLs. EPCs for sediment are based on maximum values.
b Risk to aquatic receptors is evaluated based on surface water and sediment data.
c Analysis of solids (i.e., soil and sediment) was reported as dry weight.
NOTES:
COPC - Constituent of Potential Concern
CASRN - Chemical Abstracts Service Registration Number
EPC - Exposure Point Concentration
Table 5
Calculation of Average Daily Doses for Mallard Duck
Ecological Exposure Area 2
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCp EPCi NIRw ADDW Pf NIRf NIRp ADDp Af NIRa ADDa Sf NIRs ADDs BF ADDt SUF AUF ADDtot
Analyte COPEC in Water
(mg/L)
COPEC in Solid
(mg/kg)
Slope, or Plant
Uptake (BAF)Intercept
Estimated1
Concentration
in Vegetation
(mg/kg dry)
Slope, or
Invertebrate
Uptake (BAF)
Intercept
Estimated2
Concentration
in
Invertebrates
(mg/kg dry)
Water
Ingestion Rate
(L/kg BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Plant Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg BW/day)
Plant Ingestion
Rate, Dry
(kg/kg BW/day)
Unadjusted
Average Daily
Dose Plant
(mg/kg/day)
Fraction Diet
Invertebrates
(percent)
Invertebrates
Ingestion Rate
(kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose
Invertebrates
(mg/kg/day)
Fraction Diet
Soil (percent)
Soil Ingestion3
Rate (kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose Soil
(mg/kg/day)
Bioavailability3
(percent)
Omnivore
Intake
(mg/kg/day)
Seasonal Use
Factor
(unitless)
Area Use Factor
(Exposure
Area/Home
Range)
Adjusted Total
Omnivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.1556 0.0008 0 1 0 0.057 0.009 48%0.068 0.0049 0 48%0.007 0 3.3%0.00029 0 100%0.01 1 0.010 0.000086
Barium 41 0.03 1.23 1 41 0.057 0 48%0.068 0.0049 0.00606 48%0.007 0.2963 3.3%0.00029 0.01196 100%0.3143 1 0.010 0.00303
Manganese 0.0997 0.05 0.057 0.006 48%0.068 0.0049 0 48%0.007 0 3.3%0.00029 0 100%0.01 1 0.010 0.000055
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
AVERAGE DAILY DOSE VIA:
WATER
1 Bechtel Jacobs Company 1998a; Baes et al. 1984 (Mo); Environmental Restoration Division - Manual ERD-AG-003 1999; default value of 1 is used for constituents for which a BAF could not be found.
2 Bechtel Jacobs Company 1998b, Table 2, median BAFs for sediment to benthic invertebrates for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn; Sample et al. 1998b (earthworms) for Mn; default value of 1 is used for constituents for which a BAF could not be found.
PLANTS/VEGETATION INVERTEBRATES SOIL
3 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
Table 6
Calculation of Average Daily Doses for Great Blue Heron
Ecological Exposure Area 2
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCfish EPCi NIRw ADDw Af NIRf NIRa ADDa Af NIRa ADDa BF ADDt SUF AUF ADDtot
Analyte COPEC in
Water (mg/L)
COPEC in Solid
(mg/kg)
Fish Uptake
(BCF)
Estimated1
Concentration
in Fish (mg/kg)
Slope, or
Invertebrate
Uptake (BAF)
Intercept
Estimated2
Concentration
in
Invertebrates
(mg/kg dry)
Water
Ingestion Rate
(L/kg BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Animal Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg
BW/day)
Fish Ingestion
Rate (kg/kg
BW/day)
Unadjusted
Average Daily
Dose
(mg/kg/day)
Fraction Diet
Invertebrates
(percent)
Invertebrates
Ingestion Rate
(kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose
Invertebrates
(mg/kg/day)
Bioavailability3
(percent)
Piscivore
Intake
(mg/kg/day)
Seasonal Use
Factor
(unitless)
Area Use
Factor
(Exposure
Area/Home
Range)
Adjusted Total
Piscivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.1556 0.1 0.02 1 0.16 0.045 0.007 90%0.18 0.162 0.003 10%0.004 0.0006 100%0.01 1 0.019 0.0002
Barium 41 4 0 1 0 0.045 0 90%0.18 0.162 0 10%0.004 0 100%0 1 0.019 0
Manganese 0.0997 400 39.89 0.682 -0.809 0.09 0.045 0.004 90%0.18 0.162 6.463 10%0.004 0.0003 100%6.47 1 0.019 0.120
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
WATER FISH INVERTEBRATES
AVERAGE DAILY DOSE VIA:
1 Al (Voigt et al. 2015), mean of fish tissue BAFs; Cu (USEPA 1980); Environmental Restoration Division - Manual ERD-AG-003 1999.
3 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
2 Bechtel Jacobs Company 1998b, Table 2, median BAFs for sediment to benthic invertebrates for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn; Sample et al. 1998b (earthworms) for Mn; default value of 1 is used for constituents for which a BAF could not be found.
Table 7
Calculation of Average Daily Doses for Muskrat
Ecological Exposure Area 2
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCp NIRW ADDw Pf NIRf NIRp ADDp Sf NIRs ADDs BF ADDt SUF AUF ADDtot
Analyte COPEC in Water
(mg/L)
COPEC in Solid
(mg/kg)
Slope, or Plant
Uptake (BAF)Intercept
Estimated1
Concentration
in Vegetation
(mg/kg dry)
Water Ingestion
Rate (L/kg
BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Plant Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg BW/day)
Plant Ingestion
Rate, Dry
(kg/kg/day)
Unadjusted
Average Daily
Dose Plant
(mg/kg/day)
Fraction Diet
Soil (percent)
Soil Ingestion
Rate (kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose Soil
(mg/kg/day)
Bioavailability2
(percent)
Herbivore
Intake
(mg/kg/day)
Seasonal Use
Factor (unitless)
Area Use Factor
(Exposure
Area/Home
Range)
Adjusted Total
Herbivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.1556 0.0008 0.0 0.97 0.15 99%0.3 0.045 0 1%0.000273 0 100%0.1509 1 1 0.1509
Barium 41 0.03 1.23 0.97 0 99%0.3 0.045 0.05496 1%0.000273 0.00146 100%0.0564 1 1 0.0564
Manganese 0.0997 0.05 0 0.97 0.10 99%0.3 0.045 0 1%0.000273 0 100%0.097 1 1 0.0967
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
AVERAGE DAILY DOSE VIA:
WATER PLANTS / VEGETATION SOIL
1 Bechtel Jacobs Company 1998a; Baes et al. 1984 (Mo); Environmental Restoration Division - Manual ERD-AG-003 1999; default value of 1 is used for constituents for which a BAF could not be found.
2 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
Table 8
Calculation of Average Daily Doses for River Otter
Ecological Exposure Area 2
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCPREY NIRw ADDw Pf NIRf NIRa ADDa BF ADDt SUF AUF ADDtot
Analyte
COPEC in
Water (mg/L)
COPEC in Solid
(mg/kg)
Fish Uptake
(BCF)
Estimated1
Concentration
in Fish (mg/kg)
Water
Ingestion Rate
(L/kg BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Animal Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg BW/day)
Fish Ingestion
Rate (kg/kg
BW/day)
Unadjusted
Average Daily
Dose
(mg/kg/day)
Bioavailability2
(percent)
Piscivore
Intake
(mg/kg/day)
Seasonal Use
Factor
(unitless)
Area Use
Factor
(Exposure
Area/Home
Range)
Adjusted Total
Piscivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.1556 0.1 0.02 0.081 0.013 100%0.19 0.19 0.003 100%0.016 1 0.01 0.000188
Barium 41 4 0 0.081 0 100%0.19 0.19 0 100%0 1 0.01 0
Manganese 0.0997 400 39.89 0.081 0.008 100%0.19 0.19 7.58 100%7.588 1 0.01 0.091574
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
AVERAGE DAILY DOSE VIA:
DRINKING WATER FISH
1 Al (Voigt et al. 2015), mean of fish tissue BAFs; Cu (USEPA 1980); Environmental Restoration Division - Manual ERD-AG-003 1999.
Table 9
Hazard Quotients for COPCs - Aquatic Receptors
Ecological Exposure Area 2
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Mallard Duck Great Blue Heron Muskrat River Otter
Aluminum 7.78E-07 1.70E-06 7.82E-02 9.73E-05
Barium 1.46E-04 0.00E+00 1.09E-03 0.00E+00
Manganese 3.07E-07 6.68E-04 1.88E-03 1.78E-03
Mallard Duck Great Blue Heron Muskrat River Otter
Aluminum 7.78E-08 1.70E-07 7.82E-03 9.73E-06
Barium 7.28E-05 0.00E+00 7.52E-04 0.00E+00
Manganese 1.58E-07 3.44E-04 1.36E-03 1.29E-03

Hazard Quotients greater than or equal to 1 are highlighted in gray and in boldface.
Wildlife Receptor Hazard Quotient Estimated using the 'No Observed Adverse Effects Level'
AquaticAnalyte
Analyte
Wildlife Receptor Hazard Quotient Estimated using the 'Lowest Observed Adverse Effects
Aquatic
NOTES:
NM - Not measured due to lack of a Toxicity Reference Value
Plants Mammal/Terr.
Vertebrates Fish Invertebrates Birds Soil
BW IRF IRW PF AM AF AI AB SF HR SUF
kg kg/kg BW/day L/kg BW/day %%%%%%hectares unitless
Meadow Volea 0.033 0.33 0.21 97.6%0%0%0%0%2.4%0.027 1
Muskratb 1.17 0.3 0.97 99.3%0%0%0%0%0.7%0.13 1
Mallard Duckc 1.134 0.068 0.057 48.3%0%0%48.3%0%3.3%435 1
American Robind 0.08 0.129 0.14 40%0%0%58%0%2%0.42 1
Red-Tailed Hawke 1.06 0.18 0.058 0%91.5%0%0%8.5%0%876 1
Bald Eaglef 3.75 0.12 0.058 0%28%58%0%13.5%0.5%2199 1
Red Foxg 4.54 0.16 0.085 6%89%0%2%0%3%1226 1
River Otterh 6.76 0.19 0.081 0%0%100%0%0%0%348 1
Great Blue Heroni 2.229 0.18 0.045 0%0%90%9.5%0%0.5%227 1
NOTES:
a BW, IRf, IRw, PF, HR from USEPA 1993 (sections 2-328 and 2-329); SF from Sample and Suter 1994
b BW, IRf, IRw, PF, HR from USEPA 1993 (sections 2-340 and 2-341); SF from TechLaw Inc. 2013; IRF from Nagy 2001
c BW, PF, AI, HR from USEPA 1993 (sections 2-43 and 2-45); SF from Beyer et al. 1994; IRF from Nagy 2001
d BW, PF, AI, HR from USEPA 1993 (sections 2-197 and 2-198); SF from Sample and Suter 1994; IRF from Nagy 2001
e BW, PF, AM, AB, IRF, HR from USEPA 1993 (sections 2-82 and 2-83)Ecological ReceptorsBW - Body Weight
kg - Kilograms
IR - Ingestion Rate
HR - Home Range
HERBIVORE
OMNIVORE
CARNIVORE
PISCIVORE
kg/kg BW/day - Kilograms Food per Kilograms Body Weight per Day
L/kg BW/day - Liters Water per Kilogram Body Weight per Day
Algorithm ID
Units
Parameter
Exposure Parameters for Ecological Receptors
Ecological Exposure Area 4
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Table 1
Seasonal Use
Factorj
Home
RangeBody Weight Food Ingestion Rate Water Ingestion
Rate
Dietary Composition
f BW, PF, AF, AM, AB, HR from USEPA 1993 (sections 2-91 and 2-97); IRF from Nagy 2001
g BW, PF, AF, AI, HR from USEPA 1993 (sections 2-224 and 2-225); SF from Beyer et al. 1994
h BW, IRw, AF, HR from USEPA 1993 (sections 2-264 and 2-266); SF from Sample and Suter 1994; IRF from Nagy 2001
i BW, PF, AF, AI, HR from USEPA 1993 (sections 2-8 and 2-9); SF from Sample and Suter 1994; IRF from Nagy 2001
j Seasonal Use Factor is set to a default of 1 to be overly conservative and protective of ecological receptors.
SUF - Seasonal Use Factor
PF - Plant Matter Ingestion Percentage
AM - Mammal/Terrestrial Vertebrate ingestion percentage
AF - Fish Ingestion Percentage
AB - Bird Ingestion Percentage
SF - Soil Ingestion Percentage
Table 2
Toxicity Reference Values for Ecological Receptors
Ecological Exposure Area 4
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Mallard Duck
(mg/kg/day)
Great Blue
Heron
(mg/kg/day)
Bald Eagle
(mg/kg/day)
Muskrat
(mg/kg/day)
River Otter
(mg/kg/day)
American
Robin
(mg/kg/day)
Red-Tailed
Hawk
(mg/kg/day)
Meadow Vole
(mg/kg/day)
Red Fox
(mg/kg/day)
Aluminuma 110 110 110 1.93 1.93 110 110 1.93 1.93
Antimonya NA NA NA 0.059 0.059 NA NA 0.059 0.059
Arsenicb 2.24 2.24 2.24 1.04 1.04 2.24 2.24 1.04 1.04
Bariumc 20.8 20.8 20.8 51.8 51.8 20.8 20.8 51.8 51.8
Berylliuma NA NA NA 0.532 0.532 NA NA 0.532 0.532
Borona, b 28.8 28.8 28.8 28 28 28.8 28.8 28 28
Cadmiuma 1.47 1.47 1.47 0.77 0.77 1.47 1.47 0.77 0.77
Calcium EN EN EN EN EN EN EN EN EN
Chromium, Totald 1 1 1 2740 2740 1 1 2740 2740
Chromium VI (hexavalent)a NA NA NA 9.24 9.24 NA NA 9.24 9.24
Chromium IIIa 2.66 2.66 2.66 2.4 2.4 2.66 2.66 2.4 2.4
Cobalta 7.61 7.61 7.61 7.33 7.33 7.61 7.61 7.33 7.33
Coppera 4.05 4.05 4.05 5.6 5.6 4.05 4.05 5.6 5.6
Iron EN EN EN EN EN EN EN EN EN
Leadb 1.63 1.63 1.63 4.7 4.7 1.63 1.63 4.7 4.7
Magnesium EN EN EN EN EN EN EN EN EN
Manganesea 179 179 179 51.5 51.5 179 179 51.5 51.5
Mercurye 3.25 3.25 3.25 1.01 1.01 3.25 3.25 1.01 1.01
Molybdenuma, d 3.53 3.53 3.53 0.26 0.26 3.53 3.53 0.26 0.26
Nickela 6.71 6.71 6.71 1.7 1.7 6.71 6.71 1.7 1.7
Potassium EN EN EN EN EN EN EN EN EN
Seleniuma 0.29 0.29 0.29 0.143 0.143 0.29 0.29 0.143 0.143
Sodium EN EN EN EN EN EN EN EN EN
Strontiuma, d NA NA NA 263 263 NA NA 263 263
Thalliuma NA NA NA 0.015 0.015 NA NA 0.015 0.015
Titanium NA NA NA NA NA NA NA NA NA
Vanadiuma 0.344 0.344 0.344 4.16 4.16 0.344 0.344 4.16 4.16
Zinca 66.1 66.1 66.1 75.4 75.4 66.1 66.1 75.4 75.4
Nitrated NA NA NA 507 507 NA NA 507 507
Analyte
Aquatic
TRVs (NOAEL)
Terrestrial
Mallard Duck
(mg/kg/day)
Great Blue
Heron
(mg/kg/day)
Bald Eagle
(mg/kg/day)
Muskrat
(mg/kg/day)
River Otter
(mg/kg/day)
American
Robin
(mg/kg/day)
Red-Tailed
Hawk
(mg/kg/day)
Meadow Vole
(mg/kg/day)
Red Fox
(mg/kg/day)
Aluminuma 1100 1100 1100 19.3 19.3 1100 1100 19.3 19.3
Antimonya NA NA NA 0.59 0.59 NA NA 0.59 0.59
Arsenicb 40.3 40.3 40.3 1.66 1.66 40.3 40.3 1.66 1.66
Bariumc 41.7 41.7 41.7 75 75 41.7 41.7 75 75
Berylliuma NA NA NA 6.6 6.6 NA NA 6.6 6.6
Borona, b 100 100 100 93.6 93.6 100 100 93.6 93.6
Cadmiuma 2.37 2.37 2.37 10 10 2.37 2.37 10 10
Calcium EN EN EN EN EN EN EN EN EN
Chromium, Totald 5 5 5 27400 27400 5 5 27400 27400
Chromium VI (hexavalent)a NA NA NA 40 40 NA NA 40 40
Chromium IIIa 2.66 2.66 2.66 9.625 9.625 2.66 2.66 9.625 9.625
Cobalta 7.8 7.8 7.8 10.9 10.9 7.8 7.8 10.9 10.9
Coppera 12.1 12.1 12.1 9.34 9.34 12.1 12.1 9.34 9.34
Iron EN EN EN EN EN EN EN EN EN
Leadb 3.26 3.26 3.26 8.9 8.9 3.26 3.26 8.9 8.9
Magnesium EN EN EN EN EN EN EN EN EN
Manganesea 348 348 348 71 71 348 348 71 71
Mercurye 0.37 0.37 0.37 0.16 0.16 0.37 0.37 0.16 0.16
Molybdenuma, d 35.3 35.3 35.3 2.6 2.6 35.3 35.3 2.6 2.6
Nickela 11.5 11.5 11.5 3.4 3.4 11.5 11.5 3.4 3.4
Potassium EN EN EN EN EN EN EN EN EN
Seleniuma 0.579 0.579 0.579 0.215 0.215 0.579 0.579 0.215 0.215
Sodium EN EN EN EN EN EN EN EN EN
Strontiuma, d NA NA NA 2630 2630 NA NA 2630 2630
Thalliuma NA NA NA 0.075 0.075 NA NA 0.075 0.075
Vanadiuma 0.688 0.688 0.688 8.31 8.31 0.688 0.688 8.31 8.31
Zinca 66.5 66.5 66.5 75.9 75.9 66.5 66.5 75.9 75.9
Nitrated NA NA NA 1130 1130 NA NA 1130 1130
TRV - Toxicity Reference Value
Analyte Aquatic
TRVs (LOAEL)
Terrestrial
NA - Not available
b USEPA 2005 EcoSSL
c Only a single paper (Johnson et al., 1960) with data on the toxicity of barium hydroxide to one avian species (chicken) was identified by USEPA (2005); therefore, an avian TRV could not
be derived and an Eco-SSL could not be calculated for avian wildlife (calculation requires a minimum of three results for two test species). Johnson et al. (1960) reports a subchronic
NOAEL of 208.26 mg/kg/d. The NOAEL was multiplied by an uncertainty factor of 0.1 to derive a very conservative TRV of 20.8 mg/kg/d.
d Sample et al. 1996
a CH2M Hill. 2014. Tier 2 Risk-Based Soil Concentrations Protective of Ecological Receptors at the Hanford Site. CHPRC-01311. Revision 2. July.
Http://pdw.hanford.gov/arpir/pdf.cfm?accession=0088115
Table 2 (Cont.)
NOTES:
NOAEL - No Observed Adverse Effects Level
LOAEL - Lowest Observed Effects Level
EN - Essential nutrient
Table 3
Exposure Area and Area Use Factors for Ecological Receptors
Ecological Exposure Area 4
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Mallard
Duck
Great Blue
Heron Muskrat River
Otter
Bald
Eagle
American
Robin
Red-Tailed
Hawk
Meadow
Vole Red Fox
Ecological Exposure Area 4 3.4 0.78%1.50%100%0.98%0.15%100%0.388%100%0.28%
NOTES:
Area Use Factor (AUF)
Exposure Point Exposure Areaa
(hectares)
a Exposure Area 4 is located northwest of Unit 5 Inactive Ash Basin. The area includes a section of the Broad River, upstream of the Active Ash Basin, and
wooded areas on the plant side of the river.
Table 4
EPCs for Use in the Risk Assessment
Ecological Exposure Area 4
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
COPC CASRN
Sediment EPC Used in
Risk Assessmentc
(mg/kg)
Surface Water EPC Used
in Risk Assessment
(mg/L)
Aluminum 7429-90-5 0.299
Barium 7440-39-3 160
Aquatic EPCsa, b
a EPCs for surface water and sediment are based on maximum detected values.
b Surface water and sediment data are used to evaluate aquatic receptors.
c Analysis of solids (i.e., soil and sediment) was reported as dry weight.
NOTES:
COPC - Constituent of Potential Concern
CASRN - Chemical Abstracts Service Registration Number
EPC - Exposure Point Concentration
Table 5
Calculation of Average Daily Doses for Mallard Duck
Ecological Exposure Area 4
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCp EPCi NIRw ADDW Pf NIRf NIRp ADDp Af NIRa ADDa Sf NIRs ADDs BF ADDt SUF AUF ADDtot
Analyte COPEC in Water
(mg/L)
COPEC in Solid
(mg/kg)
Slope, or Plant
Uptake (BAF)Intercept
Estimated1
Concentration
in Vegetation
(mg/kg dry)
Slope, or
Invertebrate
Uptake (BAF)
Intercept
Estimated2
Concentration
in
Invertebrates
(mg/kg dry)
Water
Ingestion Rate
(L/kg BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Plant Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg BW/day)
Plant Ingestion
Rate, Dry
(kg/kg BW/day)
Unadjusted
Average Daily
Dose Plant
(mg/kg/day)
Fraction Diet
Invertebrates
(percent)
Invertebrates
Ingestion Rate
(kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose
Invertebrates
(mg/kg/day)
Fraction Diet
Soil (percent)
Soil Ingestion3
Rate (kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose Soil
(mg/kg/day)
Bioavailability3
(percent)
Omnivore
Intake
(mg/kg/day)
Seasonal Use
Factor
(unitless)
Area Use Factor
(Exposure
Area/Home
Range)
Adjusted Total
Omnivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.3 0.0008 0.0000 1 0.00 0.057 0.017 48%0.068 0.0049 0.000000 48%0.007 0.0000 3.3%0.00029 0.00000 100%0.02 1 0.008 0.000133
Barium 160 0.03 4.8000 1 160.00 0.057 0.000 48%0.068 0.0049 0.023648 48%0.007 1.1561 3.3%0.00029 0.04668 100%1.2264 1 0.008 0.009586
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
AVERAGE DAILY DOSE VIA:
WATER
1 Bechtel Jacobs Company 1998a; Baes et al. 1984 (Mo); Environmental Restoration Division - Manual ERD-AG-003 1999; default value of 1 is used for constituents for which a BAF could not be found.
2 Bechtel Jacobs Company 1998b, Table 2, median BAFs for sediment to benthic invertebrates for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn; Sample et al. 1998b (earthworms) for Mn; default value of 1 is used for constituents for which a BAF could not be found.
PLANTS/VEGETATION INVERTEBRATES SOIL
3 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
Table 6
Calculation of Average Daily Doses for Great Blue Heron
Ecological Exposure Area 4
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCfish EPCi NIRw ADDw Af NIRf NIRa ADDa Af NIRa ADDa BF ADDt SUF AUF ADDtot
Analyte COPEC in
Water (mg/L)
COPEC in Solid
(mg/kg)
Fish Uptake
(BCF)
Estimated1
Concentration
in Fish (mg/kg)
Slope, or
Invertebrate
Uptake (BAF)
Intercept
Estimated2
Concentration
in
Invertebrates
(mg/kg dry)
Water
Ingestion Rate
(L/kg BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Animal Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg
BW/day)
Fish Ingestion
Rate (kg/kg
BW/day)
Unadjusted
Average Daily
Dose
(mg/kg/day)
Fraction Diet
Invertebrates
(percent)
Invertebrates
Ingestion Rate
(kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose
Invertebrates
(mg/kg/day)
Bioavailability3
(percent)
Piscivore
Intake
(mg/kg/day)
Seasonal Use
Factor
(unitless)
Area Use
Factor
(Exposure
Area/Home
Range)
Adjusted Total
Piscivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.3 0.1 0.03 1 0.30 0.045 0.013 90%0.18 0.162 0.005 10%0.004 0.0011 100%0.02 1 0.015 0.000
Barium 160 4 0.00 1 0.00 0.045 0.000 90%0.18 0.162 0.000 10%0.004 0.0000 100%0.00000 1 0.015 0.000
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
WATER FISH INVERTEBRATES
AVERAGE DAILY DOSE VIA:
1 Al (Voigt et al. 2015), mean of fish tissue BAFs; Cu (USEPA 1980); Environmental Restoration Division - Manual ERD-AG-003 1999.
3 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
2 Bechtel Jacobs Company 1998b, Table 2, median BAFs for sediment to benthic invertebrates for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn; Sample et al. 1998b (earthworms) for Mn; default value of 1 is used for constituents for which a BAF could not be found.
Table 7
Calculation of Average Daily Doses for Muskrat
Ecological Exposure Area 4
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCp NIRW ADDw Pf NIRf NIRp ADDp Sf NIRs ADDs BF ADDt SUF AUF ADDtot
Analyte COPEC in Water
(mg/L)
COPEC in Solid
(mg/kg)
Slope, or Plant
Uptake (BAF)Intercept
Estimated1
Concentration
in Vegetation
(mg/kg dry)
Water Ingestion
Rate (L/kg
BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Plant Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg BW/day)
Plant Ingestion
Rate, Dry
(kg/kg/day)
Unadjusted
Average Daily
Dose Plant
(mg/kg/day)
Fraction Diet
Soil (percent)
Soil Ingestion
Rate (kg dry/kg
BW/day)
Unadjusted
Average Daily
Dose Soil
(mg/kg/day)
Bioavailability2
(percent)
Herbivore
Intake
(mg/kg/day)
Seasonal Use
Factor (unitless)
Area Use Factor
(Exposure
Area/Home
Range)
Adjusted Total
Herbivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.3 0.0008 0.0000 0.97 0.29 99%0.3 0.045 0.00000 1%0.000273 0.00000 100%0.29 1 1 0.29
Barium 160 0.03 4.8000 0.97 0.00 99%0.3 0.045 0.21449 1%0.000273 0.00568 100%0.22 1 1 0.22
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
AVERAGE DAILY DOSE VIA:
WATER PLANTS / VEGETATION SOIL
1 Bechtel Jacobs Company 1998a; Baes et al. 1984 (Mo); Environmental Restoration Division - Manual ERD-AG-003 1999; default value of 1 is used for constituents for which a BAF could not be found.
2 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
Table 8
Calculation of Average Daily Doses for River Otter
Ecological Exposure Area 4
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
EPCw EPCs EPCPREY NIRw ADDw Pf NIRf NIRa ADDa BF ADDt SUF AUF ADDtot
Analyte
COPEC in
Water (mg/L)
COPEC in Solid
(mg/kg)
Fish Uptake
(BCF)
Estimated1
Concentration
in Fish (mg/kg)
Water
Ingestion Rate
(L/kg BW/day)
Unadjusted
Average Daily
Dose Water
(mg/kg/day)
Fraction Diet
Animal Matter
(percent)
Food Ingestion
Rate, Wet
(kg/kg BW/day)
Fish Ingestion
Rate (kg/kg
BW/day)
Unadjusted
Average Daily
Dose
(mg/kg/day)
Bioavailability2
(percent)
Piscivore
Intake
(mg/kg/day)
Seasonal Use
Factor
(unitless)
Area Use
Factor
(Exposure
Area/Home
Range)
Adjusted Total
Piscivore
Average Daily
Dose
(mg/kg/day)
Aluminum 0.3 0.1 0.03 0.081 0.024 100%0.19 0.19 0.0057 100%0.030 1 0.010 0.000292
Barium 160 4 0.00 0.081 0.000 100%0.19 0.19 0.000 100%0.000 1 0.010 0.000000
NOTES:
EPC - Exposure Point Concentration BF - Bioavailability Factor SUF - Seasonal Use Factor
NIR - Normalized Ingestion Rate BAF - Bioaccumulation Factor AUF - Area Use Factor
ADD - Average Daily Dose BCF - Bioconcentration Factor
AVERAGE DAILY DOSE VIA:
DRINKING WATER FISH
1 Al (Voigt et al. 2015), mean of fish tissue BAFs; Cu (USEPA 1980); Environmental Restoration Division - Manual ERD-AG-003 1999.
2 Bioavailability is set to a default of 100% to be conservative and protective of ecological receptors.
Table 9
Hazard Quotients for COPCs - Aquatic Receptors
Ecological Exposure Area 4
Baseline Ecological Risk Assessment
Duke Energy
Cliffside Steam Station, Mooresboro, NC
Mallard Duck Great Blue Heron Muskrat River Otter
Aluminum 1.21E-06 2.64E-06 1.50E-01 1.51E-04
Barium 4.61E-04 0.00E+00 4.25E-03 0.00E+00
Mallard Duck Great Blue Heron Muskrat River Otter
Aluminum 1.21E-07 2.64E-07 1.50E-02 1.51E-05
Barium 2.30E-04 0.00E+00 2.94E-03 0.00E+00

Hazard Quotients greater than or equal to 1 are highlighted in gray and in boldface.
1 The bald eagle was added to this risk assessment model because the species is federally protected and represents a raptor
that preys upon fish, primarily, while the Red-Tailed Hawk primarily preys upon small terrestrial vertebrates (e.g., rodents,
snakes, etc.). Hazard quotient calculations for the Bald Eagle include hypothetical consumption of fish that inhabit adjacent
surface water areas in addition to terrestrial vertebrates that inhabit adjacent areas.
Wildlife Receptor Hazard Quotient Estimated using the 'No Observed Adverse Effects Level'
AquaticAnalyte
Analyte
Wildlife Receptor Hazard Quotient Estimated using the 'Lowest Observed Adverse Effects
Aquatic
NOTES:
NM - Not measured due to lack of a Toxicity Reference Value

Appendix C

Exposure Modeling and
Human Health Risk
Assessment for Diesel
Emissions

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C-1
Air Dispersion Modeling for CSS Ash Basin Closure
I used screening models to evaluate the potential for both cancer and non-cancer risks from
diesel exhaust emissions due to increased trucking operations related to the closure of the coal
ash basins at the Duke Energy Cliffside Steam Station (CSS). The calculated cancer and non-
cancer risks are associated with increased diesel trucking activity near residential properties that
lie along transportation corridors near CSS. Modelling was conducted for simultaneous closure
of the inactive Unit 5 basin/active ash basin in the following combinations (Unit 5/Active
Basin): CIP/CIP, CIP/Excavation, CIP/Hybrid, Excavation/CIP, Excavation/Excavati on, and
Excavation/Hybrid. Details of these closure options are provided in the main body of the report.
Emission rates for the fleet of diesel trucks operating as part of closure activities were calculated
based on truck activity and emission factors representative of the region from the U.S.
Environmental Protection Agency (EPA) Mobile Vehicle Emissions Simulator (MOVES). I
estimated airborne concentrations of emitted pollutants using the EPA model AERMOD for
atmospheric dispersion and transport. AERMOD is a Gaussian plume model that accounts for
the impacts of meteorology and land characteristics on airborne pollutants. Together these tools
allowed for the estimation of airborne concentrations of diesel particulate matter (DPM) emitted
from passing trucks and subsequent calculation of potential non-cancer health impacts (hazard
index [HI]) and cancer risk estimates (excess lifetime cancer risk [ELCR]).
The following sections detail the data and models used in this evaluation, including the
meteorological data, trucking operations, emissions calculations, and dispersion modeling. I also
include additional discussion of the results and associated uncertainties.
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C-2
Methodology
Meteorological Data
AERMOD-ready five-year1 meteorological data sets of hourly surface meteorological data for
the years 2012–2016 were generated from the National Weather Service (NWS) Surface
Observing System station at the Shelby-Cleveland County Regional Airport (KEHO) in Shelby,
North Carolina.2 The Shelby-Cleveland County Regional Airport is located approximately 15
km from CSS. I judged this station to be representative of the meteorology in the region of CSS.
Surface parameters applied to the modeling study included wind speed and direction,
temperature, pressure, relative humidity, and cloud cover. Twice daily rawinsonde3 observations
of upper air winds and temperatures were also taken from Greensboro, North Carolina (KGSO),
which, at 195 km from CSS, is the closest upper air sounding site.
The meteorological data were processed using AERMET (v16216) with default options.4
AERSURFACE5 was used to define the land-use characteristics in the region around the surface
observational site (i.e., Shelby-Cleveland County Regional Airport). The surface characteristics,
which are important when calculating the level of atmospheric dispersion in meteorological
modeling, include surface roughness, albedo,6 and Bowen ratio7.

1 Use of five years of meteorological data is standard in regulatory application of AERMOD (EPA Guideline on
Air Quality Models, Section 8.3.1, 2005).
2 Integrated surface hourly weather observations are available at ftp://ftp.ncdc.noaa.gov/pub/data/noaa/. 2-minute
average ASOS wind data are available at ftp://ftp.ncdc.noaa.gov/pub/data/asos-onemin/.
3 A rawinsonde is a device typically carried by weather balloons that collects meteorological and atmospheric
data, especially regarding winds.
4 AERMET is an EPA program that will read standard recorded meteorological observations, calculate boundary
layer meteorological parameters, and output the data in a format readable by the AERMOD model (U.S. EPA
2016).
5 AERSURFACE is the EPA model used to calculate average land -use characteristics. It can read standard
databases and calculate the average values of surface roughness, albedo, and Bowen ratios, consistent with EPA
recommended methods.
6 Albedo is the ratio of reflected flux density to incident flux density. It indicates how much incoming energy is
absorbed by the land surface. Light surfaces (such as snow) will reflect higher levels of incoming energy.
7 Bowen ratio is the ratio of sensible to latent heat fluxes from the earth’s surface up into the air. Lower Bowen
ratio is indicative of greater water content in the land surface.
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C-3
Trucking Operations
Diesel emissions estimates from trucking are based on the number of trucks passing a given
receptor location along transportation corridors used during ash basin closure. The total number
of offsite truckloads required for transporting ash, earthen fill, and geosynthetic materials under
the CSS closure options were projected by Duke Energy (2018). These truckloads equate to
13,230 total truck passes for the CIP/CIP closure; 16,334 total truck passes for the
CIP/Excavation closure; 13,192 truck passes for the CIP/Hybrid closure; 14,762 truck passes for
the Excavation/CIP closure; 17,866 truck passes for Excavation/Excavation closure; and 14,724
truck passes for the Excavation/Hybrid closure. I included only loads hauling earthen fill,
geosynthetic materials, and other materials along offsite transportation corridors in
transportation emissions estimates for all closure options because trucks hauling ash do not
leave CSS. Onsite loads of over-excavated soil8 and earthen fill were also not included in
emissions estimates. Trucks hauling earthen fill are assumed to travel 11 miles one way from
the site, and trucks hauling geosynthetic material are assumed to travel 260 miles one way from
Georgetown, South Carolina. Air modeling is conducted for a receptor along the transportation
route within the 11-mile radius traveled both by trucks hauling earthen fill and trucks hauling
geosynthetic material. Trucks are assumed to travel in round trips, so the number of material
loads was doubled to represent the number of truck passes.
AERMOD
The AERMOD modeling system (U.S. EPA 2016) is a steady-state plume model that
incorporates air dispersion based on planetary boundary layer turbulence structure and scaling
concepts, including treatment of surface and elevated sources. EPA’s “Guideline on Air Quality
Models” (U.S. EPA 2016) identifies AERMOD as the preferred refined dispersion modeling
technique for receptors within 50 km of a modeled source.
The latest version of AERMOD (v16216r) was used with default options to conduct the
modeling.

8 The 12 in. of soil beneath the ash that would also be removed as part of excavation.
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C-4
Modeled Source and Receptors
AERMOD was configured to simulate an approximately 1-km stretch of road. This road
segment was assumed representative of any segment along the proposed transportation
corridors. The road emission source was modeled as a continuous distribution of emission along
the road due to the passage of multiple trucks. In the cross-road direction, the emissions drop off
based on a normal (or Gaussian) distribution. The road emissions were represented using a line
of closely spaced volume sources running down the center of the road. Volume sources define
the initial pollutant distribution based on an initial release height and the standard deviation of
the normal distribution in both the vertical and horizontal directions (sigma-y and sigma-z). The
appropriate values for the release height and standard deviations were calculated based on
guidance in EPA’s Haul Road Working Group Final Report (U.S. EPA 2010).
Transport and dispersion of pollutants away from the road segment may be sensitive to the
predominant wind directions at the site and the orientation of the road compared to those
predominant wind directions. To fully evaluate the impacts of any road segment, four
orientations of the road were considered. Modeled orientations included roads running
north/south, east/west, northeast/southwest, and northwest/southeast. For each modeled road
orientation, receptors were included on both sides of the road to represent impacts at distances
between 10 and 150 m from the edge of the road. The representative road segments and
sampling receptor locations are shown in Figure C-1.
AERMOD was run for the five-year period (2012–2016) defined by the meteorological data.
The resulting five-year average dispersion factors were assumed representative of long-term
average dispersion of truck roadway emissions along roads in this region.
1805958.000 - 2920
C-5

Figure C-1. Location of road sources (blue) and sampling receptors (red) for each of four
road orientations

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C-6
Source Emission Rates
Emission rates for mobile sources are typically calculated based on a combination of emission
factors and activity rates. The emission factors define the amount of pollutant emitted per unit
distance traveled (grams of pollutant per kilometer traveled), and the activity rates define how
much activity occurs (i.e., the number of kilometers driven by the vehicles). Emission factors
will be specific to the type of vehicle being considered, the model year, the age of the vehicle,
and the local climate. For this evaluation, EPA’s MOVES model was used to define fleet
average emission factors for various years between 2018 and 2050 (2050 is the last year
simulated by MOVES) (U.S. EPA 2015). These emission factors are specific to North Carolina
and have been selected to represent large, single-unit diesel trucks.
Tailpipe emissions from diesel trucks (DPM) are the subset of PM10 of particular interest when
evaluating the cancer and non-cancer risk estimates in this analysis. The DPM emission factors
generated by MOVES were multiplied by the expected number of trucks under each of the
considered closure options to calculate emission rates for each one.
For the cancer risk analysis, emissions were calculated as an average over the regulatory default
70-year residential exposure duration. If the truck activity for a closure option occurs over a
shorter period, the duration of the truck activity exposure is factored into the 70-year averaging
time (OEHHA 2015). These average emission rates were multiplied by the dispersion factors
calculated by AERMOD to predict airborne concentrations. The resulting values were then
multiplied by the cancer unit risk factor9 to quantify cancer risk.
For the non-cancer analysis, airborne concentrations of DPM were calculated and compared to
the non-cancer risk threshold of 5 µg/m3.10 In this case, the average concentrations are not tied
to a 70-year period and are calculated over the period of operation for each closure option.

9 A “reasonable estimate” for the inhalation unit risk of 3.0×10-4 (µg/m3)-1 was applied based on California
guidelines (OEHHA 2015).
10 North Carolina defers to EPA’s chronic non-cancer reference concentration (RfC) for diesel particulate matter
of 5 µg/m3 based on diesel engine exhaust to estimate risk from diesel emissions (Integrated Risk Information
System [IRIS]. U.S. EPA. Diesel engine exhaust).
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C-7
Uncertainties
A number of uncertainties should be considered when evaluating the modeled results. First, air
dispersion modeling is a mathematical calculation of pollutant transport and dispersion and may
differ from real world conditions. Typically, for regulatory applications, air dispersion models
are expected to predict concentrations within a factor of two (40 CFR Part 51). Longer
averaging periods, such as those used in this study, would often have lower uncertainties as
compared with shorter average periods such as 1-hour or 24-hour averages.
The calculation of emission factors is meant to represent fleet average characteristics. The fleet
of trucks used at this specific site may differ from the average values included in MOVES. This
may result in higher or lower actual emission rates. Additionally, MOVES includes predictions
of future year emission factors based on typical patterns of vehicle turnover and any regulations
scheduled to be implemented in future years. Not all future regulations are presently known and
future conditions may vary from these estimates.
For the non-cancer risk, an evaluation of the average concentrations was calculated over the
actual period of activity, which varies between closure options. For this portion of the
evaluation, there was no accounting for how long the emissions were present. The non-cancer
risk value is generally considered applicable over a period of approximately eight years. For
activities that occur for less than eight years, comparison with this risk value may overstate the
actual risk. Correspondingly, for activities that run significantly longer than eight years, there
may be sub-periods with higher average concentrations and higher associated non-cancer risk.

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C-8
Results
Worst-case impacts were calculated for each distance from the modeled road. The worst-case
result represents the highest value calculated over the four road orientations. This may not be
the same orientation for all distances. For example, a road that runs northeast/southwest aligns
with the predominant wind direction. This results in higher concentrations for receptors close to
the road. For receptors farther away from the edge of the road, the worst case occurs for a
northwest/southeast road where winds are perpendicular to the road. Worst-case results are
reported in Table 9-2 of the main report. The following sections include results for all road
orientations and distances from both sides of the road.
Model-estimated cancer risk
ELCR results for the four road orientations and both sides of the road are provided in Table C-1.

1805958.000 - 2920
C-9
Table C-1. ELCR estimates from DPM exposure due to trucking operations
associated with closure of the CSS ash basins under combinations of CIP
closure, excavation closure, and hybrid closure. Results are for each road
orientation and distances from both sides of the road (ELCR columns per
orientation).

E-W Run

NE-SW Run

N-S Run

NW-SE Run
CIP/CIP
10 m 1.5E-09 1.5E-09 1.9E-09 2.1E-09 2.1E-09 2.0E-09 1.3E-09 1.6E-09
20 m 1.5E-09 1.5E-09 1.6E-09 1.8E-09 1.8E-09 1.7E-09 1.4E-09 1.6E-09
30 m 1.3E-09 1.2E-09 1.2E-09 1.5E-09 1.4E-09 1.3E-09 1.1E-09 1.4E-09
40 m 1.1E-09 9.8E-10 1.0E-09 1.2E-09 1.2E-09 1.1E-09 9.2E-10 1.1E-09
50 m 9.2E-10 8.4E-10 8.4E-10 1.0E-09 9.7E-10 9.3E-10 7.8E-10 9.9E-10
60 m 8.1E-10 7.3E-10 7.2E-10 8.7E-10 8.4E-10 8.1E-10 6.8E-10 8.7E-10
70 m 7.2E-10 6.5E-10 6.3E-10 7.7E-10 7.3E-10 7.1E-10 6.0E-10 7.8E-10
80 m 6.5E-10 5.8E-10 5.5E-10 6.9E-10 6.5E-10 6.3E-10 5.4E-10 7.1E-10
90 m 5.9E-10 5.2E-10 4.9E-10 6.2E-10 5.8E-10 5.6E-10 4.9E-10 6.4E-10
100 m 5.4E-10 4.8E-10 4.4E-10 5.6E-10 5.2E-10 5.1E-10 4.5E-10 5.9E-10
110 m 5.0E-10 4.4E-10 4.0E-10 5.2E-10 4.8E-10 4.6E-10 4.1E-10 5.5E-10
120 m 4.7E-10 4.1E-10 3.7E-10 4.8E-10 4.4E-10 4.3E-10 3.8E-10 5.1E-10
130 m 4.4E-10 3.8E-10 3.4E-10 4.4E-10 4.0E-10 3.9E-10 3.5E-10 4.8E-10
140 m 4.1E-10 3.5E-10 3.1E-10 4.1E-10 3.7E-10 3.6E-10 3.3E-10 4.5E-10
150 m 3.9E-10 3.3E-10 2.8E-10 3.9E-10 3.4E-10 3.4E-10 3.1E-10 4.2E-10
CIP/Excavation
10 m 1.5E-09 1.5E-09 1.9E-09 2.2E-09 2.1E-09 2.0E-09 1.4E-09 1.6E-09
20 m 1.5E-09 1.5E-09 1.6E-09 1.9E-09 1.8E-09 1.7E-09 1.4E-09 1.7E-09
30 m 1.3E-09 1.2E-09 1.3E-09 1.5E-09 1.4E-09 1.4E-09 1.1E-09 1.4E-09
40 m 1.1E-09 9.9E-10 1.0E-09 1.2E-09 1.2E-09 1.1E-09 9.3E-10 1.2E-09
50 m 9.3E-10 8.5E-10 8.5E-10 1.0E-09 9.9E-10 9.4E-10 7.9E-10 1.0E-09
60 m 8.1E-10 7.4E-10 7.3E-10 8.8E-10 8.5E-10 8.1E-10 6.9E-10 8.8E-10
70 m 7.3E-10 6.5E-10 6.3E-10 7.8E-10 7.4E-10 7.1E-10 6.1E-10 7.9E-10
80 m 6.6E-10 5.9E-10 5.6E-10 6.9E-10 6.6E-10 6.3E-10 5.5E-10 7.1E-10
90 m 6.0E-10 5.3E-10 5.0E-10 6.3E-10 5.9E-10 5.7E-10 4.9E-10 6.5E-10
100 m 5.5E-10 4.8E-10 4.5E-10 5.7E-10 5.3E-10 5.2E-10 4.5E-10 6.0E-10
110 m 5.1E-10 4.5E-10 4.1E-10 5.2E-10 4.8E-10 4.7E-10 4.1E-10 5.5E-10
120 m 4.7E-10 4.1E-10 3.7E-10 4.8E-10 4.4E-10 4.3E-10 3.8E-10 5.1E-10
130 m 4.4E-10 3.8E-10 3.4E-10 4.5E-10 4.1E-10 4.0E-10 3.6E-10 4.8E-10
140 m 4.2E-10 3.6E-10 3.1E-10 4.2E-10 3.7E-10 3.7E-10 3.3E-10 4.5E-10
150 m 3.9E-10 3.4E-10 2.9E-10 3.9E-10 3.5E-10 3.4E-10 3.1E-10 4.3E-10
CIP/Hybrid
10 m 1.3E-09 1.4E-09 1.8E-09 2.0E-09 1.9E-09 1.8E-09 1.2E-09 1.5E-09
20 m 1.4E-09 1.4E-09 1.5E-09 1.7E-09 1.7E-09 1.6E-09 1.3E-09 1.5E-09
30 m 1.2E-09 1.1E-09 1.2E-09 1.3E-09 1.3E-09 1.3E-09 1.0E-09 1.3E-09
40 m 9.9E-10 9.1E-10 9.4E-10 1.1E-09 1.1E-09 1.0E-09 8.5E-10 1.1E-09
50 m 8.5E-10 7.8E-10 7.8E-10 9.4E-10 9.1E-10 8.7E-10 7.3E-10 9.2E-10
60 m 7.5E-10 6.8E-10 6.7E-10 8.1E-10 7.8E-10 7.5E-10 6.3E-10 8.1E-10
70 m 6.7E-10 6.0E-10 5.8E-10 7.2E-10 6.8E-10 6.6E-10 5.6E-10 7.3E-10
80 m 6.0E-10 5.4E-10 5.1E-10 6.4E-10 6.0E-10 5.8E-10 5.0E-10 6.6E-10
90 m 5.5E-10 4.9E-10 4.6E-10 5.8E-10 5.4E-10 5.2E-10 4.5E-10 6.0E-10
100 m 5.1E-10 4.4E-10 4.1E-10 5.2E-10 4.9E-10 4.7E-10 4.1E-10 5.5E-10
110 m 4.7E-10 4.1E-10 3.7E-10 4.8E-10 4.4E-10 4.3E-10 3.8E-10 5.1E-10
120 m 4.4E-10 3.8E-10 3.4E-10 4.4E-10 4.1E-10 4.0E-10 3.5E-10 4.7E-10
130 m 4.1E-10 3.5E-10 3.1E-10 4.1E-10 3.7E-10 3.7E-10 3.3E-10 4.4E-10
140 m 3.8E-10 3.3E-10 2.9E-10 3.8E-10 3.4E-10 3.4E-10 3.1E-10 4.2E-10
150 m 3.6E-10 3.1E-10 2.6E-10 3.6E-10 3.2E-10 3.1E-10 2.9E-10 3.9E-10

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C-10
Table C-1. (cont.) ELCR estimates from DPM exposure due to trucking operations
associated with closure of the CSS ash basins under combinations of CIP
closure, excavation closure, and hybrid closure. Results for each road
orientation and distances from both sides of the road (ELCR columns per
orientation).

E-W Run

NE-SW Run

N-S Run

NW-SE Run
Excavation/CIP
10 m 1.6E-09 1.7E-09 2.1E-09 2.4E-09 2.3E-09 2.2E-09 1.5E-09 1.8E-09
20 m 1.7E-09 1.6E-09 1.8E-09 2.0E-09 2.0E-09 1.9E-09 1.5E-09 1.8E-09
30 m 1.4E-09 1.3E-09 1.4E-09 1.6E-09 1.6E-09 1.5E-09 1.2E-09 1.5E-09
40 m 1.2E-09 1.1E-09 1.1E-09 1.3E-09 1.3E-09 1.2E-09 1.0E-09 1.3E-09
50 m 1.0E-09 9.3E-10 9.4E-10 1.1E-09 1.1E-09 1.0E-09 8.7E-10 1.1E-09
60 m 9.0E-10 8.1E-10 8.0E-10 9.8E-10 9.4E-10 9.0E-10 7.6E-10 9.8E-10
70 m 8.0E-10 7.2E-10 7.0E-10 8.6E-10 8.2E-10 7.9E-10 6.7E-10 8.7E-10
80 m 7.2E-10 6.5E-10 6.2E-10 7.7E-10 7.3E-10 7.0E-10 6.0E-10 7.9E-10
90 m 6.6E-10 5.8E-10 5.5E-10 6.9E-10 6.5E-10 6.3E-10 5.4E-10 7.2E-10
100 m 6.1E-10 5.3E-10 4.9E-10 6.3E-10 5.9E-10 5.7E-10 5.0E-10 6.6E-10
110 m 5.6E-10 4.9E-10 4.5E-10 5.8E-10 5.3E-10 5.2E-10 4.6E-10 6.1E-10
120 m 5.2E-10 4.5E-10 4.1E-10 5.3E-10 4.9E-10 4.8E-10 4.2E-10 5.7E-10
130 m 4.9E-10 4.2E-10 3.7E-10 4.9E-10 4.5E-10 4.4E-10 3.9E-10 5.3E-10
140 m 4.6E-10 4.0E-10 3.4E-10 4.6E-10 4.1E-10 4.1E-10 3.7E-10 5.0E-10
150 m 4.3E-10 3.7E-10 3.2E-10 4.3E-10 3.8E-10 3.8E-10 3.4E-10 4.7E-10
Excavation/Excavation
10 m 1.6E-09 1.7E-09 2.1E-09 2.4E-09 2.3E-09 2.2E-09 1.5E-09 1.8E-09
20 m 1.7E-09 1.6E-09 1.8E-09 2.0E-09 2.0E-09 1.9E-09 1.5E-09 1.8E-09
30 m 1.4E-09 1.3E-09 1.4E-09 1.6E-09 1.6E-09 1.5E-09 1.2E-09 1.5E-09
40 m 1.2E-09 1.1E-09 1.1E-09 1.3E-09 1.3E-09 1.2E-09 1.0E-09 1.3E-09
50 m 1.0E-09 9.3E-10 9.3E-10 1.1E-09 1.1E-09 1.0E-09 8.7E-10 1.1E-09
60 m 8.9E-10 8.1E-10 8.0E-10 9.7E-10 9.3E-10 8.9E-10 7.5E-10 9.7E-10
70 m 7.9E-10 7.1E-10 6.9E-10 8.5E-10 8.1E-10 7.8E-10 6.7E-10 8.6E-10
80 m 7.2E-10 6.4E-10 6.1E-10 7.6E-10 7.2E-10 6.9E-10 6.0E-10 7.8E-10
90 m 6.5E-10 5.8E-10 5.4E-10 6.8E-10 6.4E-10 6.2E-10 5.4E-10 7.1E-10
100 m 6.0E-10 5.3E-10 4.9E-10 6.2E-10 5.8E-10 5.6E-10 4.9E-10 6.5E-10
110 m 5.6E-10 4.9E-10 4.4E-10 5.7E-10 5.3E-10 5.1E-10 4.5E-10 6.1E-10
120 m 5.2E-10 4.5E-10 4.0E-10 5.3E-10 4.8E-10 4.7E-10 4.2E-10 5.6E-10
130 m 4.9E-10 4.2E-10 3.7E-10 4.9E-10 4.4E-10 4.3E-10 3.9E-10 5.3E-10
140 m 4.6E-10 3.9E-10 3.4E-10 4.6E-10 4.1E-10 4.0E-10 3.6E-10 4.9E-10
150 m 4.3E-10 3.7E-10 3.1E-10 4.3E-10 3.8E-10 3.7E-10 3.4E-10 4.6E-10
Excavation/Hybrid
10 m 1.5E-09 1.6E-09 2.0E-09 2.2E-09 2.1E-09 2.1E-09 1.4E-09 1.7E-09
20 m 1.6E-09 1.5E-09 1.7E-09 1.9E-09 1.8E-09 1.8E-09 1.4E-09 1.7E-09
30 m 1.3E-09 1.2E-09 1.3E-09 1.5E-09 1.5E-09 1.4E-09 1.1E-09 1.4E-09
40 m 1.1E-09 1.0E-09 1.0E-09 1.2E-09 1.2E-09 1.1E-09 9.5E-10 1.2E-09
50 m 9.5E-10 8.7E-10 8.7E-10 1.0E-09 1.0E-09 9.7E-10 8.1E-10 1.0E-09
60 m 8.4E-10 7.6E-10 7.5E-10 9.1E-10 8.7E-10 8.4E-10 7.1E-10 9.1E-10
70 m 7.5E-10 6.7E-10 6.5E-10 8.0E-10 7.6E-10 7.3E-10 6.3E-10 8.1E-10
80 m 6.7E-10 6.0E-10 5.7E-10 7.1E-10 6.7E-10 6.5E-10 5.6E-10 7.3E-10
90 m 6.1E-10 5.4E-10 5.1E-10 6.4E-10 6.0E-10 5.8E-10 5.1E-10 6.7E-10
100 m 5.6E-10 5.0E-10 4.6E-10 5.9E-10 5.4E-10 5.3E-10 4.6E-10 6.1E-10
110 m 5.2E-10 4.6E-10 4.2E-10 5.4E-10 4.9E-10 4.8E-10 4.3E-10 5.7E-10
120 m 4.9E-10 4.2E-10 3.8E-10 5.0E-10 4.5E-10 4.4E-10 3.9E-10 5.3E-10
130 m 4.5E-10 3.9E-10 3.5E-10 4.6E-10 4.2E-10 4.1E-10 3.7E-10 4.9E-10
140 m 4.3E-10 3.7E-10 3.2E-10 4.3E-10 3.8E-10 3.8E-10 3.4E-10 4.6E-10
150 m 4.0E-10 3.4E-10 3.0E-10 4.0E-10 3.6E-10 3.5E-10 3.2E-10 4.4E-10

1805958.000 - 2920
C-11
Model-estimated non-cancer risk
HI results for the four road orientations and both sides of the road are provided in Table C-2.
Table C-2. HI estimates from DPM exposure due to trucking operations associated
with closure of the CSS ash basins under combinations of CIP closure,
excavation closure, and hybrid closure. Results are for each road
orientation and distances from both sides of the road (HI columns per
orientation).

E-W Run

NE-SW Run

N-S Run

NW -SE Run
CIP/CIP
10 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
20 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
30 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
40 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
50 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
60 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
70 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
80 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
90 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
100 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
110 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
120 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
130 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
140 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
150 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
CIP/Excavation
10 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
20 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
30 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
40 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
50 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
60 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
70 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
80 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
90 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
100 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
110 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
120 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
130 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
140 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
150 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
CIP/Hybrid
10 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
20 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
30 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
40 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
50 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
60 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
70 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
80 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
90 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
100 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
110 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
120 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
130 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
140 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
150 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
1805958.000 - 2920
C-12
Table C-2. (cont.) HI estimates from DPM exposure due to trucking operations
associated with closure of the CSS ash basins under combinations of CIP
closure, excavation closure, and hybrid closure. Results are for each road
orientation and distances from both sides of the road (HI columns per
orientation).

E-W Run

NE-SW Run

N-S Run

NW -SE Run
Excavation/CIP
10 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
20 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
30 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
40 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
50 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
60 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
70 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
80 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
90 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
100 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
110 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
120 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
130 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
140 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
150 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
Excavation/Excavation
10 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
20 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
30 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
40 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
50 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
60 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
70 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
80 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
90 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
100 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
110 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
120 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
130 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
140 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
150 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
Excavation/Hybrid
10 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
20 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
30 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
40 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
50 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
60 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
70 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
80 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
90 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
100 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
110 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
120 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
130 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
140 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
150 m 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Appendix D

Habitat Equivalency Analysis

1805958.000 - 2920 D-1
Habitat Equivalency Analysis
Habitat equivalency analysis (HEA) was used to estimate changes in environmental service
levels under different closure options for the Duke Energy Cliffside Steam Station (CSS). The
extent of environmental service flows currently provided by ash basin habitats (wooded areas,
open field, open water, etc.) and associated sites (borrow/landfill areas) was calculated and
compared to service flows provided by post-closure habitats in these areas.
The HEA proceeded in four steps:
1. Estimate habitat areas: The acres of different habitat types (e.g., forest,
open field, open water, wetland) that would be affected by closure under each
closure option (i.e., cap in place [CIP], excavation, and hybrid closures) were
estimated from aerial imagery.
2. Evaluate environmental service levels: The relative level of environmental
services provided by these habitats was estimated in terms of net primary
productivity (NPP).
3. Apply discounting for future services: The relative levels of environmental
services were calculated over time according to the construction
implementation schedule developed by Duke Energy (2018) and expressed in
units of discounted service acre-years (DSAYs).
4. Calculate discounted environmental services: DSAYs were summed
across the gains and losses of each habitat type to produce a net gain or loss
in environmental service levels for each closure option.
Estimate Habitat Areas
Acreages of current habitat types were calculated from geographic information system (GIS)
files provided by Duke Energy that included spatial representations of the current acreage of
open field, wetland, wooded area, and open water habitats surrounding the ash basin. The
acreages of ash basin to be closed and land converted to landfill or borrow pit were based on
information provided by Duke Energy (2018) according to the assumptions below. For the
1805958.000 - 2920 D-2
excavation and hybrid options, the closure-by-removal portions of the ash basin were assumed
to be restored to historical, pre-basin conditions. Historical acreage of forested, open field, and
stream habitat types were estimated by measuring aerial photographs from 1955 provided in the
comprehensive site assessment (CSA; SynTerra 2018a) using GIS. Unclassified current habitat
areas in the ash basin footprint were assumed to be bare ground and to have a 0% service value.
Historical habitat types were broadly classified into forest, open water, and open-unclassified
areas since not all currently measured habitat types (e.g., scrub-shrub) could be resolved from
historical images. Historical areas of forest sub-habitat types not resolved in the historical
imagery were estimated by assuming the current (non-basin) site-wide percentages of broadleaf
forest (70%), needleleaf forest (29%), and wetland forest (<1%) were applied to the historical
forest areas within the ash basin footprint. Historical areas of open-unclassified (as forest or
open water) habitat types were estimated by assuming the current site-wide percentages of
scrub-shrub (56%), emergent wetland (0%), and open field (44%) applied to these areas within
the historical ash basin footprint. It is important to note that not all closure options impacted all
basin habitat areas, thus different closure options may be modeled in the HEA using different
total areas.
Additional assumptions used to calculate habitat areas included:
 Stream habitats in the ash basin were not indicated for CSS in historical
imagery and not included in the NPP services in ash basin restoration.
 Fill material for closure was assumed to be derived from excavation of basin
dam features and new, onsite borrow pits. The areal extent of these borrow
pits was calculated from the volume (cubic yards) of required earthen fill
material, assuming borrow pits would be dug to 15 ft.
 Area lost to borrow pit excavation was assumed to contain forest habitat,
which is the predominant non-basin habitat type on the CSS property.
 Borrow material required for CIP closure of the Unit 5 basin was assumed to
not be available from closure activities in the active ash basin.
1805958.000 - 2920 D-3
Evaluate Environmental Services
NPP was used to standardize environmental services across habitat types. NPP is a measure of
how much photosynthesis occurs in an area greater than the amount required by the plants for
immediate respiration needs. Fundamentally, NPP is a measure of the energy available to
perform environmental services and is a useful currency for comparing habitats (Efroymson et
al. 2003). NPP is often referred to in terms of carbon fixation or carbon storage, as the removal
of carbon from the atmosphere is a primary reaction of photosynthesis.
Of the habitats currently occurring on the site, broadleaf, needleleaf, and mixed forested areas
have the highest NPP; that is, per acre of forest, photosynthesis fixes more carbon/produces
more energy for environmental services (Ricklefs 2008). As such, NPP service levels for all
habitat types were normalized to the NPP service level of forested habitat. Specifically, the
service levels for all habitat types were expressed as a proportion of the maximum wooded area
service level (He et al. 2012).
To compare results between the different closure options, a set of assumptions was used for all
options evaluated.
 Figure 22.12 from Ricklefs (2008) was used as the basis for determining
relative rates of NPP for different ecosystem types. For this evaluation,
temperate forest (woodland) was considered the base habitat with a relative
NPP of 100%. Other habitat types were normalized as a proportion of that
value based on the relative levels of NPP shown in Ricklefs’ Figure 22.12
(2008), using temperate grassland as representative of open fields and
freshwater environments as representative of open water.
 Based on Ricklefs’ Figure 22.12 (2008), NPP values for open field
and open water habitats were assumed to be 40% of the forest value.
However, because aquatic habitats of the ash basin may not be
functionally equivalent to naturally occurring freshwater ecosystems
(e.g., less abundant or diverse vegetation), a habitat quality
1805958.000 - 2920 D-4
adjustment factor of 4 was applied, lowering the relative NPP value
for ash basin open water habitat to 10% of temperate forest NPP.
 Figure 2c from He et al. (2012) was used to estimate NPP of woodland areas
based on stand age.
 The NPP functions for the three forest types (broadleaf, needleleaf,
mixed) from Figure 2c of He et al. (2012) were digitized to allow
calculation of NPP by stand age. For example, for mixed forests this
function shows rapidly increasing NPP up to a maximum at 45 years,
after which the NPP declines slightly to level off at approximately
85% of the maximum.
 All wooded areas currently occurring in the ash basin or on borrow or
landfill areas were assumed to be 50 years old, which, based on He et
al. (2012), provide approximately 97% of maximum NPP function in
the case of broadleaf and mixed forests and 84% for needleleaf
forests. Other habitats were normalized from the higher value using
the relative rates of NPP described above.
 Baseline levels of service (NPP) in the absence of closure activities were
assumed to continue at the current rate for 150 years, accounting for slight
changes in wooded area NPP by age as calculated from the NPP function of
He et al. (2012).
Apply Discounting for Future Services
HEA applies a discounting function when calculating the amount of environmental services
derived from an acre over a year and uses as its metric a discounted service acre-year, or DSAY.
Discounting is necessary because environmental services occurring in the future are assumed to
be less valuable to people than the same services performed now (Dunford et al. 2004;
Desvousges et al. 2018; Penn undated). This allows the environmental services occurring far in
the future to be considered on par with contemporary services. Thus, factors determining when
1805958.000 - 2920 D-5
closure and remediation begin and the duration of these processes are important parameters of
the final DSAY estimate.
I used the closure schedule provided by Duke Energy (2018) to develop timelines for habitat
loss and gain under each closure option. For purposes of the HEA, only site preparation,
construction, and site restoration times were included. Pre-design and design permitting periods
were assumed to have no effect on environmental services. The closure schedule estimated
duration of each activity in months; however, since the HEA model calculates DSAYs on an
annual basis, the activity durations were rounded up the nearest full year. This has a negligible
impact on DSAY estimates.
The following assumptions were then used to standardize timing of activities among the closure
options:
 For all closure options, removal of existing onsite habitats was assumed to
occur in the year that construction begins and was assumed to be completed
the same year such that no environmental service is provided by the end of
the first construction year.
 Environmental services of areas used for borrow or as landfill were assumed
to be lost in the year construction starts, and borrow/landfill site preparation
was assumed to be complete the same year such that no environmental
service is provided by the end of the first construction year.
 Environmental service gains from restoration (ash basin and borrow area)
were assumed to begin in the year following completion of construction
activities.
 Post-closure habitats were presumed eventually to provide the same level of
service as equivalent pre-closure habitats with the following conditions:
 Forests would be age 0 in the year when restoration was completed
and would generate an increasing level of NPP as they grow,
1805958.000 - 2920 D-6
following the rates calculated from the NPP curves of He et al.
(2012).
 Restored open field habitat would take five years (based on
professional judgement) to reach the baseline relative to forest NPP of
40%, with service levels increasing linearly over that time.
 Restored wetland and stream habitat would be functionally equivalent
to natural freshwater ecosystems and would provide an NPP relative
to forests of 40% after five years (based on professional judgement),
increasing linearly over that time.
 Periodic mowing is required to maintain a grass cap, so grass cap was
assumed never to reach a level of service equivalent to an open field.
Grass cap was assumed to have 20% of the NPP service level for open
field, which is 8% of forest NPP. Grass cap was assigned a post-
closure service level of 8%, with full service attained in 2 years.
 Bare ground was assumed to provide no environmental service.
 The base year for discounting is 2019 for all closure options.
 A discount rate of 3% is applied for all closure options.
 The HEA is run for 150 years for all closure options.
Calculate Discounted Environmental Services
Calculation of DSAYs is a summation of the discounted losses and gains in service values
across habitat types. The net DSAYs calculated for each closure option are reported in Table 10-
1 of the main body of this report.
A sensitivity analysis of key parameters (based on professional experience) and assumptions
used in the HEA was conducted to evaluate how sensitive the HEA results are to changes in (1)
the duration over which the services were evaluated (i.e., 150 years), (2) the assumed relative
NPP of ash basin open water and open fields, and (3) habitat created by restoration of borrow
1805958.000 - 2920 D-7
areas. The results are discussed in the context of uncertainty in the net environmental benefit
analysis (NEBA) in Appendix E.

Appendix E

Net Environmental Benefit
Analysis

1805958.000 - 2920 E-1
Net Environmental Benefit Analysis
Net environmental benefit analysis (NEBA) is a structured framework for comparing impacts
and benefits to environmental services to support decision-making (Efroymson et al. 2003,
2004). In the NEBA application for the Cliffside Steam Station (CSS) ash basin closure, a risk-
ranking approach, based on that described by Robberson (2006), was applied. The risk-ranking
approach develops alphanumerical estimates of relative risk by closure option and by attribute
(e.g., risk to a receptor, change in environmental services), which allows comparison of the
relative differences in impact between closure options to a variety of attributes. In this way,
tradeoffs can be visualized to inform decision-making.
Risk-Ranking Matrix
The risk-ranking matrix includes two axes that characterize risk. The y-axis shows the level of
impact, or risk, to an attribute, and the x-axis shows the duration of the impact (which is directly
related to the time to recovery). Both are important to evaluate the relative differences in risk
posed by closure options. A moderate level of impact over a long duration can potentially have
an overall greater negative impact on the environment than a higher impact over a very short
period (Robberson 2006). The pattern of shading of the risk matrix conveys this general
principle, though the exact shading of the cells is based on best professional judgement.
Robberson (2006) describes darker shading as indicating a higher level of concern over the level
of impact to a resource or environmental service. The NEBA matrix developed by the
Operational Science Advisory Team-2 (OSAT 2011) used a similar color coding approach to
compare risk from further cleanup of oil on beaches of the Gulf of Mexico following the
Deepwater Horizon oil spill. The risk-ranking matrix used in the NEBA of closure options for
the CSS ash basins is shown in Table E-1.

1805958.000 - 2920 E-2
Table E-1. Risk-ranking matrix for impacts and risk from closure activities. Darker
shading and higher codes indicate greater impact.

Duration of Impact (years)
10–15
(4)
5–9
(3)
1–4
(2)
<1
(1) % Impact No meaningful risk -- -- -- --
<5% (A) 4A 3A 2A 1A
5–19% (B) 4B 3B 2B 1B
20–39% (C) 4C 3C 2C 1C
40–59% (D) 4D 3D 2D 1D
60–79% (E) 4E 3E 2E 1E
>80% (F) 4F 3F 2F 1F
The percent impact levels (e.g., <5%, 5–19%) were defined based on best professional
judgement and regulatory precedent. A <5% impact characterizes a very minor potential or
expected impact that may be functionally indistinct from baseline conditions due to uncertainty
in metrics or the estimated effects. As such, this level of impact was given no shading,
regardless of the duration of impact. Impacts between 5–19% are considered low in the NEBA
framework (Efroymson et al. 2003). This impact level was shaded to reflect this low risk. Levels
of impact >20% were separated at intervals of 20% based on best professional judgement and
consistent with the risk-ranking approach used by Robberson (2006).
Similarly, the categories used to define duration of impact were based on best professional
judgment and regulatory precedent. Robberson (2006) defines recovery in <1 year as “rapid,”
with shading that indicates a generally low level of concern across the levels of impact. The
remaining categories of time in the risk-ranking matrix were divided at roughly 5-year intervals.
As Robberson (2006) notes, the exact size of the risk matrix is a function of decisions made
about scaling the matrix, which is a function of the closure and remediation being considered
and the attributes included in the NEBA. The risk-ranking matrix applied here could have been
defined differently. For example, the duration of impact categories could have been expanded to
six (e.g., <1 year, 1–3 years, 3–6 years, 6–10 years, 10–15 years, >15 years), which would have
changed the alphanumeric risk ratings and perhaps some of the shading of attributes evaluated
in the NEBA. The purpose of the risk matrix, and the risk ratings that result from it, is to
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consolidate the results from a variety of different analyses for a variety of different data types
and attributes into a single framework for comparative analysis. It is imperative, however, to
consider the underlying information used to develop the risk ratings to interpret the differences
between closure options, particularly when percent impacts or durations of closure options are
similar but receive different risk ratings. It is inappropriate to assume a risk rating for one
attribute is scientifically equivalent to the risk rating of another attribute because the
comparative metrics that form the foundation of the risk ratings can be fundamentally different
(e.g., a hazard quotient for risk to a bird species is different from discounted service acre-years
[DSAYs] for environmental services from a habitat). Thus, the risk ratings in the NEBA matrix
permit a relative comparison of impacts between closure options within attributes. Decision-
makers can use the NEBA framework to identify the relative impacts of closure options across
many different attributes, but the NEBA matrix does not, by design, elevate, or increase the
value of, any specific risk or benefit in the framework.
Risk Rating Sensitivity
Uncertainty in a NEBA can be evaluated by examining the uncertainty in the assumptions and
analyses used as inputs to the risk-ranking matrix. The following sections examine how
differences in assumptions could affect relative risk ratings in the NEBA framework for
attributes found to have levels of impact. Attributes for which no meaningful risk was found
(e.g., human health risk assessments, ecological health risk assessments) are not included in the
following discussion.
Noise and congestion from trucking traffic
I used the number of trucks per day passing1 a receptor along a near-site transportation corridor
as a metric to examine the differences in noise and traffic congestion under the closure options. I
compared the increase in truck passes due to hauling earthen fill, geosynthetic material, and

1 Truck passes per day resulting from trucking activities is calculated as the total number of loads required to
transport earthen fill, geosynthetic materials, and other materials multiplied by two to account for return trips.
The resulting total number of passes is then divided evenly among the total number of months of trucking time
multiplied by 26 working days per month.
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other materials under the closure options2 to the current number of truck passes for the same
receptor.
The current (or baseline) number of truck passes was estimated from North Carolina
Department of Transportation (NCDOT) annual average daily traffic (AADT) data collected at
thousands of locations across the state and the proportion of road miles driven by large trucks in
North Carolina. AADT is an estimated daily traffic volume at a specific location, which
captures traffic in all lanes traveling in both directions and is assumed to represent typical traffic
volume for a year.3 Not all AADT data, however, differentiate between large trucks such as
those to be used in ash basin closure and other traffic such as cars, which is a relevant
distinction when considering impacts to communities from increased noise. NCDOT performs
vehicle classification4 on trucking routes to estimate annualized truck percentage to apply to
AADT to determine truck AADT (NCDOT 2015). The average annualized truck percentage for
Rutherford and Cleveland County is 6.9%.
The precise transportation corridor for trucks travelling to and from CSS during ash basin
closure is unknown; however, likely corridors in the communities local to CSS can be identified
by examining road maps and AADT statistics. CSS is located on Duke Power Rd/McCraw Rd
(SR 1002) immediately adjacent to US Route 221-A, which is presumed to be the primary
transportation route for construction material hauling (Figure E-1). Immediately adjacent to CSS
is NCDOT Station ID 2201550, which reported 1,400 AADT in 2017, and Station ID 8001571,
which reported 1,600 AADT in 2016. Travelling south from CSS, McCraw Rd serves a rural
farming area with traffic volume ranging from 360 AADT to 980 AADT (Station ID 2201552 in
2017 and Station ID 2201553 in 2016, respectively); however, it is less likely that trucks
travelling to and from CSS would use this portion of SR 1002 and local roads since these appear

2 Truck trips to haul ash were not included in the estimate for CSS ash basin closures because trucks hauling ash
would not leave the CSS property and would not affect community receptors along the transportation corridors.
3 AADT is calculated from two days of traffic counts at each station during weekdays, excluding holidays. Raw
monitoring data consists of counts of axle pairs made by pneumatic tube counters that are converted to traffic
volume by applying axle correction factors, and expanded to annual estimates by seasonal correction factors.
Derived AADT values are checked for quality against nearby stations and historical station -specific values
(NCDOT 2015).
4 Vehicle classification is assigned based on number of axles, space between axles, weight of the first axle, and
total weight of the vehicle.
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to be small side roads that are not the shortest route to a major transportation corridor. US Route
221-A appears to be the major transportation route serving CSS, and NCDOT Station ID
8000016 on US 221-A, just south of the Duke Power Rd intersection, reported 2,900 AADT in
2017. To best capture trucking related impacts to sensitive communities along the transportation
corridor, I assumed a baseline truck passes per day of 97, which was computed by multiplying
1,400 AADT (2017 estimate from Duke Power Rd/McCraw Rd Station ID 2201550) by the
average percent of truck AADT for Rutherford and Cleveland counties (6.9%; NCDOT 2015).5

Figure E-1. NCDOT annual average daily traffic (AADT) measurement stations near CSS.
Traffic stations and AADT values considered when determining the baseline
number of truck passes are indicated as squares.

5 AADT data are not available for every road or every location along a road. It is possible during closure of the
CSS ash basins that trucks will utilize less traveled roads (i.e., with lower AADT), which would have a lower
baseline truck passes per day estimate and result in a higher percent impact from ash basin closure for these
sensitive communities; however, by choosing the lowest available AADT estimate from roads within 10 miles
of CSS along the most likely transportation corridors to and from CSS to a major road (e.g., highway), my
analyses have considered sensitive communities that would be more affected by traffic noise and congestion
from ash basin closure trucking.
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The sensitivity of the NEBA relative risk ratings to the baseline assumption of 97 trucks per day
was evaluated by calculating relative risk ratings for a range of baseline truck traffic levels,
based on the minimum and maximum AADT values for any NCDOT station within a 50-mile
radius of the CSS ash basins, using AADT from the most recent year that data are available for a
particular station, and assuming 6.9% truck traffic as previously described. Figure E-2 plots the
resulting percent impact for closure options along with the resulting relative risk rating across
the range of 2 to 11,563 truck passes per day.

Figure E-2. Sensitivity of NEBA relative risk rating for noise and congestion impacts from
trucking operations. The vertical line indicates the assumed baseline 97 truck
passes per day. The y-axis is plotted on a log10 scale and the X axis is
truncated at 500 to improve visualization.
Using a baseline truck passes per day of 97, all closure options fall into the second lowest
relative risk rating (B, 5–19%) for traffic-induced noise and congestion during closure of the
CSS ash basins (Figure E-2). The assigned relative risk ratings may be reduced to the lowest
rating (A) if the baseline traffic assumption is increased to at least 161 (CIP/Excavation).
Increasing baseline traffic above 301 truck passes per day, as in the Excavation/CIP option,
provides for a minimum risk rating in all options. Higher risk ratings would result from a lower
baseline truck traffic assumption; decreasing the baseline truck traffic assumption to 75 raises
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the risk rating to C for the Excavation/CIP closure option, while a baseline of 40 truck passes
per day would increase the risk rating for all closure options from B to C.
Traffic accidents
I evaluated risk of traffic accidents by comparing the average number of annual offsite road
miles driven between closure options relative to a baseline estimate of the current annual road
miles driven.6 I chose a baseline of 60.4 million annual truck road miles based on the reported
total vehicle miles traveled in Rutherford and Cleveland Counties, North Carolina (NCDOT
2017), multiplied by the county average 6.9% contribution of trucks to total AADT (NCDOT
2015).
The sensitivity of the NEBA relative risk ratings to the baseline assumption of 60.4 million
truck miles per year was evaluated by calculating relative risk ratings for alternative baseline
truck mile assumptions derived from the counties in NC with the minimum (Hyde County) and
maximum (Mecklenburg County) reported vehicle miles driven, resulting in a sensitivity range
estimated from 6.2million to 641 million truck miles per year. Figure E-3 plots the resulting
percent impact for the closure options, along with the resulting relative risk ratings across this
range of truck miles per year.

6 The difference between the baseline miles assumption and the closure assumption was divided by the baseline
miles assumption and multiplied by 100 to get a percent impact.
1805958.000 - 2920 E-8

Figure E-3. Sensitivity of NEBA relative risk rating for traffic accidents due to trucking
activities. The vertical line indicates the assumed baseline 60.4 million truck
miles per year. The y-axis is plotted on a log10 scale to improve visualization.
Using the 60.4-million-truck-miles baseline assumption, all closure options have an impact of
0.1% or less. All closure options have a relative risk rating of A (<5%). These relative risk
ratings do not appear to be sensitive to lower assumed baseline annual truck miles. The vertical
lines in Figure E-3 indicate the location of the baseline assumption. Reducing the baseline
assumption to the 4.1 million truck miles minimum increases percent impact up to a maximum
across all closure options of 1.6% for the Excavation/CIP option and the risk ratings are
unchanged.
Habitat Equivalency Analysis
Uncertainty in the habitat equivalency analysis (HEA) that examined disruption of
environmental services from ash basin closure was explored through sensitivity analyses of key
assumptions in the HEA. To test sensitivity, I re-ran HEA models with the following changes:
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1. Running the HEA for 100 years instead of 150 years.
2. Assuming the open water habitats of the ash ponds provide environmental
services at 40% of wooded areas instead of 10%.
3. Assuming open field habitats provide environmental services at 20% of
wooded areas instead of 40%.
4. Assuming borrow area under the CIP option for the inactive basin is restored
to open field, not reforested.
For each sensitivity analysis, all parameters in the base model were held constant except the one
parameter varied to understand the sensitivity of the model to each assumption (Table E-2).
Table E-2. Change in DSAYs from base modela for key HEA assumptions
Closure Option 100-year
modelb
Ash basin
water 40%c
Borrow
becomes fieldd
Open Field
20%e
CIP/CIP 8 −342 −13 167
CIP/Excavation −18 −342 −13 167
CIP/Hybrid −9 −342 −13 167
Excavation/CIP −16 −339 0 142
Excavation/Excavation −43 −339 0 142
Excavation/Hybrid −34 −339 0 142
a Base models were run for 150 years, with ash basin open water NPP services at 10%, borrow fields
were assumed to become forest (CIP inactive basin) or grass cap (CIP for active basin and
excavation for both basins), open field NPP services at 40%.
b Base models except the HEA was run for 100 years.
c Base models except ash basin open water NPP service at 40%.
d Base models except borrow pits were assumed to become open field for CIP and hybrid options.
e Base models except open field NPP services decreased to 20%.
Running HEAs for 100 years increased net DSAYs slightly for the CIP/CIP option and
decreased net DSAYs slightly for the other closure options. Increasing the ash basin open water
service level to 40% resulted in similar net negative DSAYs for all options. Assuming borrow
areas would be returned to open field resulted in a decrease in net DSAYs for all closure options
that include CIP for the Unit 5 inactive ash basin. There are no borrow areas that will be
reforested in the Unit 5 basin excavation closure option or any of the active ash basin closure
options, so there is no net change in DSAYs for those options.
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Looking at the change in net DSAYs between the sensitivity models and their base models, the
changes in assumptions have relatively consistent effects on net DSAYs. For example, changing
ash basin open water services from 10 percent to 40 percent affects all closure options equally,
since the same level of service change is applied over the same areal extent for all closure
options. Assuming open field services at 20% results in a small net benefit since the level of
service lost from open fields currently present on both basins is halved. Changing the service
level of borrow acreage habitat after borrow is complete only affects closure options that
assume the borrow area will be restored to forested habitat (CIP for the Unit 5 basin). However,
since the directionality of net NPP services provided by the closure options does not change
under this sensitivity analysis (i.e., CIP/CIP still results in a net loss of NPP services while all
other options result in a net gain), this demonstrates that the model can differentiate between
relative differences in NPP service level changes with consistency.
Changes in net DSAYs with changing assumptions may change the relative risk rating applied
to a closure option in the NEBA. However, the relative similarity in the way DSAYs change
with assumptions between the various closure options and the results that all options except CIP
closure of both basins (CIP/CIP) produce net gains in NPP services and that CIP/CIP closure
results in net NPP services losses under any sensitivity analysis supports the relative risk ratings
for decision support in the NEBA.
Closure Option Assumptions
The following assumptions were used to calculate NEBA input values related to trucking
activities and habitat acreages.
 The density of ash was assumed to be 1.2 ash tons/CY.
 Borrow pit acreage required to supply earthen fill and cover material was
assumed to be dug to a depth of 15 ft to meet volume requirements. Borrow
pits not specifically identified were assumed to contain a mixed forest habitat
that would be restored upon closure completion.
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 Excavation was assumed to proceed at a rate of 1,000,000 CY/year for all
types of excavation material combined including ash, underlying over-
excavated or residual soil, and dam and embankment material.
 CIP cover systems were assumed to require two layers of geosynthetic
material. New landfill areas were assumed to require five layers of
geosynthetic material. Geosynthetic material was assumed to be transported
from Georgetown, South Carolina, at a rate of six loads per day and 3 acres
per load.
 Covers/caps for both CIP and landfills were assumed to receive 18 in. of
cover soil plus 6 in. of topsoil. New landfills also were assumed to receive 2
ft of liner soil. Topsoil was assumed to come from an offsite commercial
facility requiring no additional borrow area.
 Unless otherwise specified, offsite borrow material and topsoil were assumed
to be from sources 11 miles away (one way).
 Offsite truck capacity was assumed to be 20 CY of ash or earthen material.
 Working hours were assumed to be 10 hr/day, 6 days/week, and 26
days/month.
 Earthen fill material was assumed to be hauled in at a rate based on 1,000,000
CY/year.
 In excavated areas, 1 ft of over-excavation of residual soil was assumed.
When restoring these areas, 6 in. of top soil addition was assumed necessary
to establish vegetative stabilization over the total area.