20200057 Ver 1_Tab K - Risk Assessment_20200109

Carteret County Navigation Project
Atlantic Harbor Maintenance Dredging & Living Shoreline
Summary of Sediment Quality
Carteret County is requesting authorization to conduct maintenance dredging within the navigation channel
and inner harbor of the Atlantic Harbor of Refuge. A previous emergency maintenance project conducted
in summer 2018 provided partial relief to the navigation burden experienced along the entrance to Atlantic
Harbor of Refuge.
Sediment Testing - Approach
To support development of a dredging plan and associated permitting, sediment cores from Atlantic Harbor
were collected and tested in March 2018. Five sites were sampled for chemical analysis beginning inside
the harbor entrance and extending southwest along the existing channel as shown in Figure 1: AH-2, AH-
4, AH-5, AH-6, and AH-7. Chemical analysis on the core composites was conducted in accordance with
the USACE guidance, Sediment Testing Guidelines forDredged Material Proposed for Disposalln Federal
Project Disposal Areas by Applicants. A variety of analytes were tested and can be grouped into the
following categories:
• Volatile Organic Compounds
• Semivolatile Organic Compounds
• Total Petroleum Hydrocarbons
• Extractable Petroleum Hydrocarbons
• Volatile Petroleum Hydrocarbons
• Metals
• Pesticides
The data collected from Atlantic Harbor were screened by comparing values to relevant benchmarks.
Benchmarks included those developed by the U.S. Environmental Protection Agency (USEPA), North
Carolina Department of Environmental Quality (NCDEQ), and National Oceanic and Atmospheric
Administration (NOAA) and were taken from the following sources:
• USEPA (2018), Region 4 Ecological Risk Assessment Supplemental Guidance, Sediment
Screening Values for Hazardous Waste Sites, Marine/Estuarine Sediment, Ecological Screening
Value (ESV)
• NCDEQ (2018), Preliminary Soil Remediation Goals (PSRG), Protection of Groundwater
Screening Value
• NOAA (Buchman, 2008), Screening Quick Reference Tables (SQuiRTs), Marine Sediment,
Threshold Effects Levels and Effects Range -Low
USEPA (2018) provides sediment screening values to provide regional direction for implementation of the
Ecological Risk Assessment Guidance for Superfund. This guidance is appropriate for Superfund sites
under the authority of the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA) and regulated by the Office of Land and Emergency Management (OLEM). The supplemental
guidance clarifies national guidance at both Resource Conservation and Recovery Act (RCRA) and
Superfund sites.
1

NCDEQ (2018a) has developed Preliminary Soil Remediation Goals. These initial screening goals are used
to help determine if site contaminant concentrations meet unrestricted use standards. A subset is used for
the protection of groundwater PSRGs. These were developed using a USEPA soil leaching model with
conservative assumptions and default values appropriate for North Carolina.
Finally, NOAA has developed screening concentrations for inorganic and organic contaminants across
multiple media (Buchman, 2008). They are intended for preliminary screening purposes and do not
represent clean-up levels. Benchmarks in terms of Effects Range -Low (ERLs) and Threshold Effects Levels
(TELs) are provided. The ERLs are based upon a database primarily of synoptic marine sediment chemistry
and sediment toxicity bioassay data. TELs are similar to ERLs with the following differences: database for
TELs is much larger and the calculations make use of the non -toxic samples.
In addition to the screening analysis, data from three sites were incorporated into a chemical risk calculator
developed by the NC Division of Waste Management (NCDWM) and consistent with USEPA risk
assessment guidance. The Risk Calculator (NCDEQ, 2018b) estimates the risks associated with current, or
potential future human exposure to contaminated soil, groundwater, surface water, and vapor and to
estimate contaminant migration through soil and groundwater. It was designed to evaluate multiple
exposure routes associated with all contaminated environmental media at a site.
Sediment Testing - Results
A summary of sediment testing for Atlantic Harbor is shown in Table 1 and Table 2. The full report
providing the results is provided in Tab J - Chemical Analysis.
Screening Comparison
Values greater that the associated screening level are highlighted in the summary tables (Table 1 and Table
2). When compared to screening levels elevated concentrations of certain metals, semi -volatile organic
compounds, and pesticides occurred within the harbor (site AH-5) and near the entrance (site AH-4). Some
of the measurements exceeded screening goals for protection of groundwater.
By contrast, additional testing outside of the harbor (e.g., AH-2) showed decreased levels of the same
contaminants. Semi volatile organic data for stations AH-2, AH-6 and AH-7 were primarily non -detect or
below the reporting limit and there were no exceedances of the screening levels. For metals, the only
elevated concentrations at these sites were for total chromium (AH-2 and AH-6) and manganese (AH-2).
Sources of the contaminates found in the Atlantic Harbor sediments are most likely derived from historical
use of the harbor. Pollutants generated from harbor activities, especially legacy practices that were not as
protective of the environment, typically include metals and petroleum hydrocarbons. Hydrocarbons can
enter the water column and sediments via discharges from boats and other sources (e.g., refueling, bilge or
fuel discharge), spills, and stormwater runoff. In addition, metals used in a variety of boat operation and
maintenance activities as well as construction of marinas and boats can also be introduced into the
environment. Petroleum hydrocarbons, particularly polycyclic aromatic hydrocarbons (PAHs), and many
metals, absorb to sediments and can persist in the environment for long periods of time.
3

TABLE 1
SUMMARY OF ANALYTICAL DETECTIONS
VOLATILE ORGANIC COMPOUNDS, SEMIVOLATILE ORGANIC COMPOUNDS, AND PETROLEUM HYDROCARBONS
ATLANTIC HARBOR
Boring ID:
Sample ID:
Sample Depth / Interval (ft bss):
Sample Type:
Analyte CAS No. EPA I'I PSRG NOAA NOAATEL 1s1 ERL 141 Units
G1
0.5
G
AH-02-0318
G2
3.1
G
G3
5.7
G
C1
0 - 6.2
C
G1
0.5
G
AH-04-0318
G2
2.7
G
G3
4.8
G
C1
0 - 5.3
C
G1
0.5
G
G1-DUP
0.5
G/ DUP
AH-05-0318
G2
1.6
G
G3
2.7
G
C1
0 - 3.2
C
C1-DUP
0 - 3.2
C/ DUP
G1
0.5
G
AH-06-0318
G2
3.7
G
G3
6.8
G
C1
0 - 7.3
C
G1
0.5
G
AH-07-0318
G2
2.8
G
G3
5.1
G
C1
0 - 5.6
C
Volatile Organic Compounds
Acetone 67-64-1
25,000
pg/kg
ND ND ND
NA ND 13 ND
NA
27 ND 16 ND
NA
NA
ND ND ND
NA
ND ND
ND
NA
Carbon disulfide
75-15-0
131
4,100
pg/kg
ND
ND
ND
NA
ND
ND
ND
NA
11
ND
ND
ND
NA
NA
ND
ND
ND
NA
ND
ND
ND
NA
Methylene Chloride
75-09-2
667
25
pg/kg
ND
ND
ND
NA
7.5
7.1
5.6
NA
13
10
8.3
15
NA
NA
ND
ND
ND
NA
ND
ND
ND
NA
Toluene
108-88-3
568
8,300
pg/kg
ND
ND
3.6
NA
ND
ND
ND
NA
ND
ND
ND
ND
NA
NA
ND
ND
ND
NA
ND
ND
ND
NA
Semivolatile Organic Compounds
Acenaphthene
83-32-9
6.7
16,000
6.71
16
pg/kg
NA
NA
NA
ND
NA
NA
NA
14 J
NA
NA
NA
NA
ND
ND
NA
NA
NA
ND
NA
NA
NA
ND
Acenaphthylene
208-96-81
5.9
41,000
5.87
44
1 pg/kg
NA
NA
NA
ND
NA
NA
NA
32J
NA
NA
NA
NA
52J
45J
NA
NA
NA
ND
NA
NA
NA
ND
Anthracene
120-12-7
47
1,300,000
46.9
85.3
pg/kg
NA
NA
NA
26
NA
NA
NA
50
NA
NA
NA
NA
53 J
40 J
NA
NA
NA
ND
NA
NA
NA
ND
Benzo[a]anthracene
56-55-3
75
350
74.8
261
pg/kg
NA
NA
NA
16 J
NA
NA
NA
150
NA
NA
NA
NA
130
100
NA
NA
NA
1.7
NA
NA
NA
ND
Benzo[a]pyrene JNN
50-32-8
89
120
88.8
430
pg/kg
NA
NA
NA
16 J
NA
NA
NA
130
NA
NA
NA
NA
150
110
NA
NA
NA
ND
NA
NA
NA
ND
Benzo[b]fluoranthene
205-99-2
1,200
pg/kg
NA
NA
NA
32
NA
NA
NA
200
NA
NA
NA
NA
290
220
NA
NA
NA
2.5
NA
NA
NA
ND
Benzo[g,h,i]perylene
191-24-2
310
15,600,000
1
pg/kg
NA
NA
NA
12J
NA
NA
NA
79
NA
NA
NA
NA
90
67
NA
NA
NA
ND
NA
NA
NA
ND
Benzo[k]fluoranthene
207-08-9
12,000
pg/kg
NA
NA
NA
13J
NA
NA
NA
68
NA
NA
NA
NA
120
98
NA
NA
NA
ND
NA
NA
NA
ND
Chrysene
218-01-9
108
36,000
108
384
pg/kg
NA
NA
NA
28
NA
NA
NA
150
NA
NA
NA
NA
120
110
NA
NA
NA
1.8
NA
NA
NA
ND
Dibenz(a,h)anthracene
53-70-3
1 6.2
380
6.22
63.4
pg/kg
NA
NA
NA
ND
NA
NA
NA
25 J
NA
NA
NA
NA
23 J
16 J
NA
NA
NA
ND
NA
NA
NA
ND
Fluoranthene
206-44-0
113
670,000
113
600
pg/kg
NA
NA
NA
31
NA
NA
NA
400
NA
NA
NA
NA
160
130
NA
NA
NA
ND
NA
NA
NA
ND
Fluorene
86-73-7
21
110,000
21.2
19
pg/kg
NA
NA
NA
ND
NA
NA
NA
15J
NA
NA
NA
NA
ND
ND
NA
NA
NA
ND
NA
NA
NA
ND
Indeno[1,2,3-cd]pyrene
193-39-5
340
3,900
pg/kg
NA
NA
NA
8.9 J
NA
NA
NA
74
NA
NA
NA
NA
85
61
NA
NA
NA
ND
NA
NA
NA
ND
Phenanthrene
85-01-8
87
134,000
86.7
240
pg/kg
NA
NA
NA
8.4 J
NA
NA
NA
60
NA
NA
NA
NA
ND
ND
NA
NA
NA
ND
NA
NA
NA
ND
Pyrene
129-00-0
153
440,000
153
665
pg/kg
NA
NA
NA
25
NA
NA
NA
310
NA
NA
NA
NA
260
220
NA
NA
NA
1.9
NA
NA
NA
ND
Total Petroleum Hydrocarbons (TPH)
TPH - Residual 68476-53-9
-- mg/kg NA NA NA ND NA NA NA 310 J NA NA NA NA 500 J 610 J NA NA NA ND NA NA NA ND
Extractable Petroleum Hydrocarbons (EPH)
C11-C22 Aromatics
mg/kg
NA
NA
NA ND NA
NA
NA
12
NA
NA
NA
NA
28
16
NA
NA
NA
ND
NA
NA
NA
ND
C19-C36 Aliphatics
mg/kg
NA
NA
NA ND NA
NA
NA
12
NA
NA
NA
NA
ND
ND
NA
NA
NA
ND
NA
NA
NA
ND
C9-C18 Aliphatics
mg/kg
NA
NA
NA ND NA
NA
NA
ND
NA
NA
NA
NA
15
ND
NA
NA
NA
ND
NA
NA
NA
ND
Volatile Petroleum Hydrearbons (VPH)
Not detected above laboratory method detection limit.
Notes
ft bss = feet below sediment surface
G = Grab sample
C = Composite sample
DUP = Field duplicate sample
CAS No. = Chemical Abstracts Service Number
EPA ['] = U.S. Environmental Protection Agency (USEPA), Region 4 Ecological Risk Assessment Supplemental Guidance, Sediment Screening Values for Hazardous Waste Sites, Marine/Estuarine Sediment, Ecological Screening Value (ESV) (USEPA 2018).
PSRG '2l = North Carolina Department of Environmental Quality (NCDEQ), Preliminary Soil Remediation Goals (PSRG), Protection of Groundwater Screening Value (NCDEQ 2018).
NOAA TEL Isl = National Oceanic and Atmospheric Administration (NOAA), Screening Quick Reference Tables (SQuiRTs), Marine Sediment, Threshold Effects Levels (Buchman, M.F., 2008).
NOAA ERL"= National Oceanic and Atmospheric Administration (NOAA), Screening Quick Reference Tables (SQuiRTs), Marine Sediment, Effects Range -Low (Buchman, M.F., 2008).
- = Screening criteria not established
pg/kg = micrograms per kilogram
NO = Analyte not detected above laboratory Method Detection Limit.
NA = Not Analyzed
Bold = Analyte detected above laboratory Method Detection Limit.
1293 Graham Farm Road, PO Box 68
4011. McClellanville, South Carolina 29458
NE�yA, [phone]
TECnWQILOiEs. iNc. www.athenatechnologies.com

2
TABLE 2
SUMMARY OF ANALYTICAL DETECTIONS
METALS AND PESTICIDES
ATLANTIC HARBOR
Boring ID:
Sample ID:
Sample Depth / Interval (ft bss):
Sample Type:
Analyte CAS No. EPA I'I PSRG NOAA NOAA Units
TEL [3] ERL 141
AH-02-0318
C1
0 - 6.2
C
AH-04-0318
C1
0 - 5.3
C
AH-05-0318
C1
0 - 3.2
C
C1-DUP
0 - 3.2
C/ DUP
AH-06-0318
C1
0 - 7.3
C
AH-07-0318
C1
0 - 5.6
C
Metals
Antimony
7440-36-0
2
0.9
mg/kg
ND
0.075 J
ND
0.13 J
ND
ND
Arsenic
7440-38-2
7.24
7.24
8.2
mg/kg
4.5
7.8
10
8.3
1.4
0.75
Beryllium
7440-41-7
63
mg/kg
0.37
0.58
0.69
0.62
0.092
0.054 J
Cadmium
7440-43-9
0.68
3
0.68
1.2
mg/kg
0.045 J
0.13
0.33
0.29
ND
0.0111
Chromium, Total M
7440-47-3
52.3
3.8
52.3
81
mg/kg
19
30
32
4.8
3.1
Copper
7440-50-8
18.7
1 700
18.7
34
mg/kg
6.9
34
120
99
1.8
0.73
Lead
7439-92-1
30.2
270
30.24
46.7
mg/kg
12
23
34
27
1.8
1.5
Manganese
7439-96-5
65
--
mg/kg
110
150
160
140
14
9.5
Nickel
7440-02-0
15.9
130
15.9
20.9
mg/kg
8
12
15
12
2.3
1.2
Selenium
7782-49-2
2.1
mg/kg
0.44 J
0.74
1.1
11
0.13 J
0.037 J
Silver
7440-22-4
0.73
3.4
0.73
1
mg/kg
0.024 J
0.055 J
0.069 J
0.051 J
ND
ND
Thallium
7440-28-0
0.28
mg/kg
0.11
0.2
0.3
0.25
0.019 J
0.023 J
Zinc
7440-66-6
124
1,200
124
150
mg/kg
31
80
170
150
6.3
2.9
Mercury
7439-97-6
0.13
1
0.13
0.15
mg/kg
0.03
0.059
0.11
0.099
ND
ND
Chromium, Trivalent
16065-83-1
360,000
mg/kg
19
30
38
32
4.7
2.9
Chromium, Hexavalent
18540-29-9
3.8
mg/kg
ND
ND
ND
ND
0.19 J
0.19 J
Pesticides
4,4'-DDD
72-54-8
1.2
470
1.22
2
Ng/kg
0.111
1.7
1.8
1.8
ND 1`1
ND
4,4'-DDE
72-55-9
2.1
470
2.07
2.2
Ng/kg
0.23 J
1.5
4.8
4.3
0.016 J F1
ND
4,4'-DDT
50-29-3
0.7
670
1.19
1
Ng/kg
ND
6.6
ND
ND
ND
ND
Endrinaldehyde
7421-93-4
Ng/kg
ND
ND
ND
ND
0.018JF1
ND
oxy-Chlordane
27304-13-8
Ng/kg
ND
ND
ND
ND
0.011 JP
0.012 J p
trans -Chlordane
5103-74-2
Ng/kg
ND
0.36 J
0.58 J
0.58 J
ND 1`1
ND
Notes
ft bss
= feet below sediment surface
C
= Composite sample
DUP
= Field duplicate sample
CAS No.
= Chemical Abstracts Service Number
EPA I'I
= U.S. Environmental Protection Agency (USEPA), Region 4 Ecological Risk Assessment Supplemental Guidance, Sediment Screening Values for Hazardous Waste Sites, Marine/Estuarine Sediment, Ecological Screening Value (ESV) (USEPA 2018).
PSRG Iz]
= North Carolina Department of Environmental Quality (NCDEQ), Preliminary Soil Remediation Goals (PSRG), Protection of Groundwater Screening Value (NCDEQ 2018).
NOAA TEL El
= National Oceanic and Atmospheric Administration (NOAA), Screening Quick Reference Tables (SQuiRTs), Marine Sediment, Threshold Effects Levels (Buchman, M.F., 2008).
NOAA ERL I4I
= National Oceanic and Atmospheric Administration (NOAA), Screening Quick Reference Tables (SQuiRTs), Marine Sediment, Effects Range -Low (Buchman, M.F., 2008).
= Screening criteria not established
mg/kg
= milligrams per kilogram
ND
= Analyte not detected above laboratory Method Detection Limit.
Bold
= Analyte detected above laboratory Method Detection Limit.
J
= Result is less that the Reporting Limit but greater than or equal to the Method Detection Limit and the concentration is an approximate value.
pg/kg
= micrograms per kilogram
F1
= Matrix spike and/or matrix spike duplicate recovery is outside acceptance limits.
p
= The Relative Percent Difference between the primary and confirmation column/detector is greater than 40 % . The lower value has been reported.
1293 Graham Farm Road, PO Box 68
4*411111. McClellanville, South Carolina 29458
J4 W"E P{Ak' [phone]
TECHNOLOGIES, INC. www.athenatechnologies.com

Risk Assessment
In addition to the screening comparisons described previously, an analysis of the cumulative effects of
multiple contaminants was conducted using a risk calculator developed by NCDEQ. Designed to evaluate
multiple exposure routes associated with contaminated environmental media, the calculator estimates the
risks associated with current, or potential future human exposure to contaminated soil, groundwater, surface
water, and vapor and to estimate contaminant migration through soil and groundwater.
The risk calculator was populated with sediment core data from three sites representing the areas to be
dredged: AH-2, AH-4 and AH-5. NCDWM was consulted to confirm certain features of the calculator and
to discuss assumptions for the application to Atlantic Harbor (S. Robbins, personal communication, May
29, 2018).
Based on consultation with NCDWM, the analysis focused on the User Defined receptors for Soil
Combined Pathways. The Soil Combined Pathways analysis is appropriate for evaluating sediment
exposure. Default exposure values are provided for both a recreator and a trespasser in the User
Defined receptor. These are the exposure profiles associated with placing the dredge spoil on White Point
(see discussion of sediment disposal). Sediment concentrations in mg/kg from the Atlantic Harbor core
sampling were entered into the spreadsheet under the Surface Soil Exposure sheet.
Additional assumptions used for the application to Atlantic Harbor include the following:
1. For both sites, composite values were used except for VOCs. For VOCs, there were no values under
C1 (all were NA). Therefore, max values from GI-G3, representing layers of sediment by depth,
were used in the spreadsheet. At AH-5, a duplicate composite was sampled. In this case the max
value of the two was used.
2. Where values were flagged with J, the numerical value provided was used. The J flag indicates that
the result is less that the Reporting Limit but greater than or equal to the Method Detection Limit
and the concentration is an approximate value.
Results from the calculator for the selected sites are provided in Figures 2 through 7. Application of the
tool shows potential risk associated with arsenic and chromium for all three sites with the addition of
thallium for AH-5. However, the cumulative risks under the User Defined receptor covering periodic use
for a recreator and a trespasser do not exceed the benchmark assumptions in the tool. Further, chemicals
like arsenic, chromium, and thallium have natural and common anthropogenic sources that are likely
influencing the results at these stations. The Resident receptor is not applicable in these cases because White
Point does not currently have residential development and a deed stipulation will be filed disallowing any
future residential development on the property.
C1

North Carolina DEQ Risk Calculator
Figure 2 - Risk Calculator Results for Site AH-2 - Chemical List

Summary of Risk Assessment Output
Version Date: February 2018
Basis: November 2017 EPA RSL Table
Site ID: AH-2
Exposure Unit ID:
PRIMARY CALCULATORS
Receptor
Pathway
Carcinogenic
Hazard Index
Risk exceeded?
Resident
Soil Combined Pathways
6.9E-05
4.4E-01
NO
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Non -Residential Worker
Soil Combined Pathways
4.4E-06
3.0E-02
NO
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Construction Worker
Soil Combined Pathways
0.0E+00
0.0E+00
NO
User Defined
Soil Combined Pathways
3.8E-05
2.4E-01
NO
Surface Water Combined Pathways*
0.0E+00
0.0E+00
NO
IL
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target POE Concentrations Exceeded?
Protection of Groundwater Use
Source Soil
Exceedence of 2L at POE?
NM
Source Groundwater
Exceedence of 2L at POE?
NM
Protection of Surface Water
Source Soil
Exceedence of 213 at POE?
NM
Source Groundwater
I Exceedence of 213 at POE?
NM
Notes:
1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for
lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations.
2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed
the NC 213 Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a
risk -based closure.
Figure 3. Risk Calculator Results for Site AH-2 - Summary
North Carolina DEQ Risk Calculator

North Carolina DEQ Risk Calculator
Figure 4. Risk Calculator Results for Site AH-4 - Chemical List

Summary of Risk Assessment Output
Version Date: February 2018
Basis: November 2017 EPA RSL Table
Site ID: AH-4 C1
Exposure Unit ID:
PRIMARY CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazard Index
Risk exceeded?
Resident
Soil Combined Pathways
1.1E-04
8.6E-01
YES
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Non -Residential Worker
Soil Combined Pathways
7.3E-06
7.1E-02
NO
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Construction Worker
Soil Combined Pathways
0.0E+00
0.0E+00
NO
User Defined
Soil Combined Pathways
6.2E-05
4.4E-01
NO
Surface Water Combined Pathways*
0.0E+00
0.0E+00
NO
VAPOR INTRUSION CALCULATORS qr
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target POE Concentrations Exceeded?
Protection of Groundwater Use
Source Soil
Exceedence of 2L at POE?
NM
Source Groundwater
Exceedence of 2L at POE?
NM
Protection of Surface Water
Source Soil
Exceedence of 213 at POE?
NM
Source Groundwater
I Exceedence of 213 at POE?
NM
Notes:
1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for
lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations.
2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed
the NC 213 Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a
risk -based closure.
Figure 5. Risk Calculator Results for Site AH-4 - Summary
North Carolina DEQ Risk Calculator

North Carolina DEQ Risk Calculator
Figure 6. Risk Calculator Results for Site AH-5 - Chemical List

Summary of Risk Assessment Output
Version Date: February 2018
Basis: November 2017 EPA RSL Table
Site ID: AH-5
Exposure Unit ID:
PRIMARY CALCULATORS
Receptor
Pathway
CarcinogenicRisk
Hazard Index
Risk exceeded?
Resident
Soil Combined Pathways
1.4E-04
1.3E+00
YES
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Non -Residential Worker
Soil Combined Pathways
9.3E-06
1.2E-01
NO
Groundwater Combined Pathways*
0.0E+00
0.0E+00
NO
Construction Worker
Soil Combined Pathways
0.0E+00
0.0E+00
NO
User Defined
Soil Combined Pathways
7.8E-05
6.3E-01
NO
Surface Water Combined Pathways*
0.0E+00
0.0E+00
NO
VAPOR INTRUSION CALCULATORS
Receptor
Pathway
Carcinogenic
Risk
Hazard Index
Risk exceeded?
Resident
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
Non -Residential Worker
Groundwater to Indoor Air
0.0E+00
0.0E+00
NO
Soil Gas to Indoor Air
0.0E+00
0.0E+00
NO
Indoor Air
0.0E+00
0.0E+00
NO
CONTAMINANT MIGRATION CALCULATORS
Pathway
Source
Target POE Concentrations Exceeded?
Protection of Groundwater Use
Source Soil
Exceedence of 2L at POE?
NM
Source Groundwater
Exceedence of 2L at POE?
NM
Protection of Surface Water
Source Soil
Exceedence of 213 at POE?
NM
Source Groundwater
I Exceedence of 213 at POE?
NM
Notes:
1. If lead concentrations were entered in the exposure point concentration tables, see the individual calculator sheets for
lead concentrations in comparison to screening levels. Note that lead is not included in cumulative risk calculations.
2. * = If concentrations in groundwater exceed the NC 2L Standards or IMAC, or concentrations in surface water exceed
the NC 213 Standards, appropriate remediation and/or institutional control measures will be necessary to be eligible for a
risk -based closure.
Figure 7. Risk Calculator Results for Site AH-5 - Summary
North Carolina DEQ Risk Calculator

References
Buchman, M.F. 2008. NOAA Screening Quick Reference Tables. NOAA OR&R Report 08-1. Seattle,
Washington. Office of Response and Restoration Division. National Oceanic and Atmospheric
Administration. 34 pages.
North Carolina Department of Environmental Quality (NCDEQ). 2018a. Preliminary Soil Remediation
Goals.
https://files.nc.gov/ncdeq/\Vaste%20Management/DWM/risk based remediation/Feb2018_PSRGs.pd£
North Carolina Department of Environmental Quality (NCDEQ). 2018b. Risk Calculator User Guide.
February 2018. Division of Waste Management.
U.S. Environmental Protection Agency (USEPA). 2018. Region 4 Ecological Risk Assessment
Supplemental Guidance, Sediment Screening Values for Hazardous Waste Sites, Marine/Estuarine
Sediment, Ecological Screening Value. March 2018 Update.
13