9202_Wake_EastWake_MSWLF_ASDMetals_FID1442831_20200817 (2)

CDM
Smith
5400 Glenwood Avenue, Suite 400
Raleigh, North Carolina 27612
tel: [phone]
fax: [phone]
August 17, 2020
Ms. Jaclynne Drummond
North Carolina Department of Environmental Quality
Division of Waste Management
Solid Waste Section
1646 Mail Service Center
Raleigh, North Carolina 27699-1646
Subject: Alternate Source Demonstration - Redevelopment and Sampling Report
East Wake Landfill Facility
Facility Permit No. 9202-MSWLF-1981
Dear Ms. Drummond:
CDM Smith Inc. (CDM Smith), on behalf of Wake County, is pleased to provide this Alternate Source
Demonstration (ASD) for the East Wake Landfill (Site). This ASD has been prepared in accordance with
Solid Waste rule .1633(c)(3), the Solid Waste Section (SWS) Guidelines for Alternate Source
Demonstration Submittals for Solid Waste Management Facilities (ASD Guidelines) document (July
2017), and the Work Plan approved by the SWS on February 23, 2018. The purpose of the ASD is to
demonstrate that select metals exceeding the 15A NCAC 02L .0202 (NC 2L) Groundwater Standards or
Interim Maximum Allowable Concentrations (IMACs) detected in monitoring wells at the Site are
naturally occurring and not related to a release from the landfill. Results from the ASD are provided
below.
Background
The Site is located on two parcels off Three Sisters Road in Knightdale, Wake County, North Carolina, as
shown on Figure 1. One of the parcels is owned by Carolyn Properties, LLC and contains approximately
27 acres of waste. The second parcel, owned by Mr. Rigsbee, contains approximately 46 acres of waste
located in two separate areas as shown on Figure 1. All monitoring wells for the landfill, with the
exception of the background well, are located on this parcel. This portion of the landfill operated under
Permit Number 92-02 until the two waste disposal areas ceased operations in 1983 (Area C) and 1985
(Area D). Areas C and D are shown on Figure 1. The background monitoring well for the portion of the
landfill located on the James Ervin Rigsbee property, MW-01, is located on this parcel along with a
private airport and several businesses.
WATER+ENVIRONMENT+TRANSPORTATION+ENERGY+FACILITIES ,

csmith
Ms. Jaclynne Drummond
August 17, 2020
Page 2
Groundwater assessment for Area C is being conducted under the supervision of the Inactive Hazardous
Sites — Pre -Regulatory Landfill Unit after this area of waste was determined to be eligible for the
program in the fall of 2012. Since 2012, the County had voluntarily collected groundwater samples semi-
annually from the Area C monitoring wells. On September 13, 2018, the SWS approved the
discontinuation of the groundwater monitoring of Area C, beginning with the fall 2018 sampling event.
The approved groundwater monitoring network consists of one background well (i.e. MW-01), and five
downgradient monitoring wells (i.e. MW-02, -03, -045, -04D, and -07). All groundwater monitoring wells
at the Site are sampled semi-annually and analyzed for North Carolina Appendix I volatile organic
compounds, including 1,4-dioxane for select wells, and Appendix I metals.
Landfill Geology and Hydrogeology
The Site is in the Piedmont Physiographic Province of North Carolina, which is characterized by gentle to
steep, hilly terrain with small quantities of alluvium. Saprolite, a clay -rich residual material that is the
product of in -place chemical weathering and leaching of bedrock, is commonly found in the Piedmont.
Beneath the saprolite is a transition zone consisting of weathered rock. The transition zone below the
saprolite is generally the zone in which most of the lateral groundwater flow takes place. The porosity
within the transition zone decreases with depth, as the degree of weathering decreases.
According to the North Carolina Geologic Map (Brown and Parker, 1985), the Site is located within the
Raleigh Belt, which is characterized by large areas of plutonic rocks, metavolcanics, metamorphic rocks,
and very few sediment deposits. The age of the Raleigh Belt is estimated to range from 500 to 196
million years old, with sediment deposits ranging from 63 to 2 million years old. According to the
geologic map, the foliated to massive granitic rock of the Rolesville suite underlies the Site.
The soils at the Site predominately consist of fine-grained sands, sandy silty clays, and clayey silts,
according to the Hydrogeological Field Investigation Report for the East Wake Landfill (HDR Engineering
Inc., 2011). Overburden soil thickness is variable across the Site but is generally found to be 8.5 to 24
feet below ground surface.
The transition zone beneath the saprolite is generally the zone in which most lateral groundwater flow
takes place (Daniel, 1987). This zone has the permeability of the crystalline material enhanced by shrink
and swell cracking caused by the hydration of mineral grains. Weathering of grains in the transition zone
is much less than in the saprolite, where formation of clay minerals by weathering often inhibits
groundwater flow. Groundwater flow and the depth of the water table in the transition zone generally
mirrors, and is largely controlled by, surface topography. The depth of the water table in the Piedmont
tends to vary seasonally in response to precipitation and the growing season. From mid -April through
October, vegetation intercepts much of the infiltrating precipitation before it reaches the water table,
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csmith
Ms. Jaclynne Drummond
August 17, 2020
Page 3
and evapotranspiration rates are increased. Generally, the water table will rise and fall with the seasons
(i.e. highest in the spring and lowest in the fall).
Based on groundwater elevations collected from the monitoring wells, groundwater flows southwest
towards Marks Creek. A potentiometric surface map from the most recent sampling event is presented
on Figure 1.
Exceedance Description
Barium, cobalt, thallium, and vanadium have routinely exceeded the NC 2L or IMAC Groundwater
Standards in samples collected from the downgradient monitoring wells and the background monitoring
well at the Site. These analytes were identified as the constituents of concern (COC) for this ASD.
Monitoring wells with COC exceedances are presented below:
• Barium MW-01, -03, -045, -04D
• Cobalt: MW-01, -02, -03, -045, -04D, -07
• Thallium: MW-01, -02, -03, -045, -04D, -07
• Vanadium: MW-01, -02, -03, -045, -04D, -07
A summary of detected concentrations for all monitoring wells from the fall 2014 to spring 2020
sampling events is provided in Table 1.
Work Plan Description — Monitoring Well Redevelopment and
Sampling
As part of the ASD, CDM Smith redeveloped and collected additional quarterly samples for metals
analysis from the background monitoring well MW-01 at the Site in order to generate non -turbid (i.e.
less than 10 Nephelometric Turbidity Units (NTUs)) samples. Since the first quarterly sampling event in
January 2018, a total of 10 quarterly background monitoring events have been completed.
During the quarterly events, the background well was redeveloped and purged by pumping with a
submersible pump. All monitoring wells were also redeveloped during the semi-annual sampling events.
As the wells were purged, accumulated suspended solids were removed from the wells. If the turbidity
reading was less than 10 NTUs after redevelopment, samples were immediately collected and analyzed
for total metals. If turbidity was greater than 10 NTUs, the well was allowed to settle overnight and
samples were collected within 24-hours. If turbidity remained greater than 10 NTUs within the settling
period, samples were collected for both total and dissolved metals. CDM Smith has collected dissolved
metals samples that have been filtered and preserved by the receiving laboratory since the fall 2016
sampling event. The filtered samples were held for analysis pending the total metals results. Metals that
exceeded the NC 2L or IMAC Standards were then analyzed for dissolved metals. Dissolved metal sample
results are provided in Table 1.
CO

csmith
Ms. Jaclynne Drummond
August 17, 2020
Page 4
Data Evaluation
The background monitoring well was redeveloped and sampled quarterly for metals in order to generate
new background levels for the COCs using site -specific Upper Tolerance Levels (UTLs), which are a
confidence limit of a percentile of the population. The U.S. Environmental Protection Agency's (EPA)
statistical software ProUCL 5.1 was used for statistical analyses, along with the EPA's Statistical Analysis
of Groundwater Monitoring Data and Resource Conservation and Recovery Act Facilities Unified
Guidance (Unified Guidance) document (March 2009).
The UTL is the upper limit of a tolerance interval (i.e. the concentration range designed to contain a
proportion of the underlying population of the background data from which a statistical sample is
drawn). Constituents in each compliance monitoring well will be compared to the site -specific UTL, or
new background level. According to the ASD Guidelines document, the UTL should use a coverage
proportion and confidence level of 95 percent and is also determined based on the normality of the data
set.
In order to calculate a site -specific UTL, analytical data from background monitoring wells with
turbidities less than 10 NTU were taken from the 10 most recent samples and were used for analysis per
the ASD Guidelines document. If there were not enough samples collected with turbidities under 10
NTU to complete the dataset, the samples with the next lowest turbidity were used until there were 10
samples to use for statistical analysis. To avoid analyzing the samples twice, no duplicate samples or
metals samples from the same collection date as a dissolved metals sample were used in the analysis.
Goodness -of -fit tests were used to identify data distributions and to check for the normality of the
background monitoring well sample data sets. Statistical outliers were also identified using Dixon's
outlier test. Outliers were removed from the data sets containing more than 10 samples. Based on the
Unified Guidance document, the Kaplan -Meier UTL method or a non -parametric prediction limit method
were used to statistically evaluate the data. The Kaplan -Meier UTL method was used for normally
distributed data sets with 50 percent or less non -detects. UTLs with non -normal data and/or greater
than 50 percent non -detects were calculated using a non -parametric prediction limit method.
Goodness -of -fit graphs and results from the statistical software are provided in Appendix A.
Concentration trend graphs for select monitoring wells and COCs are also provided in Appendix A. A
summary of the results is provided in Table 2.
UTLs were calculated for all COCs, except for thallium. Based on calculated UTLs and the NC 2L and IMAC
Groundwater Standards, site -specific UTLs are proposed for cobalt (2.82 parts per billion (ppb)) and
vanadium (2 ppb). A site -specific UTL was calculated for barium (158.8 ppb) but it is lower than its NC 2L
Groundwater Standards. There were not enough detections of thallium in MW-01 to calculate a UTL.
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csmith
Ms. Jaclynne Drummond
August 17, 2020
Page 5
Conclusions
Based on qualitative and quantitative evaluation of current and historic groundwater sampling data,
most NC 2L and IMAC Groundwater Standard metal exceedances may be attributed to naturally
occurring background concentrations and turbidity. Each COC is described in more detail below.
Barium
Barium has historically been detected above its NC 2L Groundwater Standard (700 ppb) in background
monitoring well MW-01 and downgradient monitoring wells MW-03, -045, and -04D, but has also
recently been detected above the standard in MW-04S and -04D. Dissolved barium was analyzed in
MW-04S and -04D due to elevated turbidity, and was also detected above the standard. The
concentration of barium will continue to be monitored. Due to minimal barium detections in the
background monitoring well, the calculated site -specific UTL for barium was less than its NC 2L
Groundwater Standard. In this case, the NC 2L Groundwater Standard will continue to be used.
Cobalt
Cobalt has been detected above its IMAC Groundwater Standard (1 ppb) in all monitoring wells at the
Site, but only historically in samples collected from MW-03. Dissolved cobalt that was analyzed for
MW-02 and -03 have been non -detect or lower than the total cobalt concentration, as shown in the
trend graphs. The trend graphs also show a decreasing trend in cobalt concentration over time in these
wells, as well as in MW-04D. Exceedances of cobalt in these wells can be attributed to elevated
turbidity, as the wells continue to be developed. In monitoring well MW-045, dissolved cobalt
concentrations have not been below the standard or the proposed site -specific UTL. Cobalt
concentrations in MW-04S have historically fluctuated and will continue to be monitored.
Thallium
Thallium has historically been detected above its IMAC Groundwater Standard (0.2 ppb) in all
monitoring wells at the Site but only recently in the background monitoring well and in MW-02.
Dissolved thallium that was analyzed for MW-01 and -02 were non -detect, as shown in the trend graphs.
Exceedances of thallium can be attributed to elevated turbidity. Due to elevated turbidity and minimal
detections in the background monitoring well, there was no site -specific UTL calculated for thallium. In
this case, the IMAC Groundwater Standard will continue to be used.
Vanadium
Vanadium exceedances are likely occurring due to natural background conditions as well as elevated
turbidity. Filtered samples of vanadium in all monitoring wells have been non -detect. Additionally, the
proposed site -specific UTL for vanadium is greater than some exceedances detected in the
downgradient wells.
CO

r
Ms. Jaclynne Drummond
August 17, 2020
Page 6
Future Actions
Groundwater monitoring wells at the Site will continue to be sampled semi-annually. CDM Smith will
continue to develop the background and downgradient monitoring wells in order to generate more non -
turbid sample data. Additionally, filtered samples will continue to be collected from monitoring wells
with elevated turbidity. Site -specific IJTLs for barium, thallium, and other metals will be re-evaluated as
additional data are collected or as needed. Additionally, if calculated site -specific UTLs are lower than
the NC 2L or IMAC Standard, the NC 2L or [MAC Standard will continue to be used as the standard for
that analyte.
If you have any questions regarding this ASD, please do not hesitate to contact me by email to
colon emf @ cdmsmith.com or by phone at [phone].
Sincerely,
6� r-
5
Mathew F. Colone, P.G., PMP
CDM Smith Inc.
cc: Elliott Cornell, Wake County
John Roberson, Wake County
References
Brown, P.M. and Parker, J.M., 1985. North Carolina Geologic Map, North Carolina Geologic Survey
Resources and Community Development, 1:500,000.
Daniel III, C.C., 1987. Statistical Analysis Relating Well Yield to Construction Practices and Siting of Wells
in the Piedmont and Blue Ridge Provinces of North Carolina. IJSGS Water Resources Report 86-4132.
HDR Engineering, Inc., 2011. Hydrogeological Field Investigation Plan — East Wake Landfill — Rigsbee
Property. FID 734444.
North Carolina Department of Environmental Quality, 2017. NC Solid Waste Section Guidelines for
Alternate Source Demonstration Submittals for Solid Waste Management Facilities. Division of Waste
Management —Solid Waste Section.
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csmith
Ms. Jaclynne Drummond
August 17, 2020
Page 7
U.S. EPA — Office of Resource Conservation and Recovery, 2009. Statistical Analysis of Groundwater
Monitoring Data and RCRA Facilities — Unified Guidance. EPA 230/R-09-007.
0

Table 1
Detected Groundwater Constituents - Metals
East Wake Landfill - Area D
Facility Permit No. 9202-MSWLF-1981
MW-01
22-Oct-14
120
0.6J
0.06BJ
0.91
2J
10B
MW-01
13-May-15
0.5J
230
45
0.2J
11
37
14
4J
0.7J
8J
37
MW-01
17-Nov-15
260
1.9
8J
25
8J
3J
0.4J
23J
68
MW-01
4-Oct-16
0.18J
120
0.63J
0.059J
1.7J
0.61J
2.4J
0.76J
0.97J
2.9J
14
MW-01
27-Apr-17
230
1.4
8.1J
4.4J
18
6.1J
6.4J
0.55J
24J
54
MW-01
3-Oct-17
130
0.61J
0.31.1
1.7J
3.6J
1. 11
5.3J
15
MW-01 (dissolved)
3-Oct-17
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-01
15-Jan-18
120
0.67BJ
2.1
0.37J
6.5J
MW-01
19-Apr-18
120
0.63J
1.8.1
1.4J
0.62.1
7.4J
MW-01
31-Aug-18
120
0.44J
1.91
3.3J
1.O1
12
MW-01
4-Oct-18
140
0.48J
3.1J
5.5J
1.5J
1.1
0.15J
6.OJ
39
MW-01 (dissolved)
4-Oct-18
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
2.6J
NA
MW-01
26-Feb-19
150
0.66J
2.2J
3.9J
1.3J
3.5J
12
MW-01 (dissolved)
26-Feb-19
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-01
17-Apr-19
230
1.3
0.23J
6.613J
19
6.7J
9.7J
181
74
MW-01 (dissolved)
17-Apr-19
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-01
2-Jul-19
1,000
8.5
0.18J
32
36
100
50
15
0.37J
110
380B
MW-01 (dissolved)
2-Jul-19
NA
NA
NA
NA
NA
NA
NA
NA
MW-01
5-Sep-19
180
1.1
3.4.1
1.91
9.3
2.8
1.4.1
0.17J
8.8
28B
MW-01 (dup)
5-Sep-19
200
1.2
4.OJ
2.9J
11
3.7
1.5J
12
34B
MW-01 (dissolved)
5-Sep-19
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-01 (dup, dissolved)
5-Sep-19
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-01
22-Apr-20
120
0.56
5.4J
MW-01 (dup)
22-Apr-20
130
0.53
4.6J
MW-02
22-Oct-14
30J
0.2J
0.5BJ
0.2BJ
0.7J
0.4J
38
MW-02
13-May-15
11
100
W12
V6J
30
13
4J
0.6J
8J
50
MW-02
17-Nov-15
0.8J
120
1.7
11
51
29
13
4J
0.4J
25
123
MW-02 (dup)
17-Nov-15
0.91
210
3.0
0.11
20
8J
45
23
6J
0.91
48
216
MW-02
4-Oct-16
0.36J
0.811
100
1.6
0.13J
16
4.9J
22
20
7.5.1
0.35J
181
150
MW-02
27-Apr-17
0.63J
120
1.5
8.1J
4.7J
23
14
3.4J
0.56J
25
140
MW-02
3-Oct-17
87J
0.86J
0.15J
7.5J
3.2J
15
18
4.OJ
0.25J
18J
160
MW-02 (dissolved)
3-Oct-17
NA
NA
NA
NA
NA
NA
0.75J
NA
NA
NA
NA
2.3J
NA
MW-02
19-Apr-18
100
1.2
8.5J
3.3J
20
12
3.8J
0.26J
151
120
MW-02 (dissolved)
19-Apr-18
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-02
4-Oct-18
32J
0.20J
2.2J
4.1J
3.8J
3.5J
42
MW-02 (dissolved)
4-Oct-18
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-02
17-Apr-19
41J
0.50J
2.OBJ
2.4J
2.9J
1.4.1
47
MW-02 (dup)
17-Apr-19
39J
0.50J
1.4BJ
1.7J
2.OJ
27
MW-02
17-Sep-19
1.6J
120
2.2
0.16J
4.2J
19
6.9J
0.31J
17
120B
MW-02 (dissolved)
17-Sep-19
NA
NA
NA
NA
NA
2.4J
NA
1.8
NA
NA
NA
NA
MW-02
22-Apr-20
29
0.31J
1.4J
1.3
10
CDM_
Smith
IDIMPage 1 of 3 Alternate Source Demonstration

Table 1
Detected Groundwater Constituents - Metals
East Wake Landfill - Area D
Facility Permit No. 9202-MSWLF-1981
MW-03
22-Oct-14
0.6J
430
0.4BJ
0.8J
0.8J
4J
3BJ
MW-03
13-May-15
11
800
2
0.2J
172
83
42J
0.2J
73
183
MW-03
17-Nov-15
11
640
2.9
0.5J
308
140
54
0.3J
103
271
MW-03
4-Oct-16
0.24J
0.35.1
360
0.10J
0.55J
1.4J
0.62.1
4.OJ
5.4.1
MW-03
27-Apr-17
370
1.01
0.26.1
2.OJ
1.6.11
MW-03
3-Oct-17
370
2.OJ
0.49.1
3.3.1
10
MW-03 (dissolved)
3-Oct-17
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-03
19-Apr-18
360
0.40J
3.5J
MW-03 (dup)
19-Apr-18
390
0.44J
3.5J
MW-03
4-Oct-18
390
1.4J
0.28.1
3.9.1
4.2J
MW-03
17-Apr-19
330
1.4J
0.38.1
3.5.1
29
MW-03
5-Sep-19
420
2.1J
0.78.1
3.9.1
6.413J
M W-03
22-Apr-20
340
3.OJ
MW-04S
22-Oct-14
0.91
730
18
4J
12J
0.11
5BJ
MW-04S
13-May-15
0.8J
900
0.5J
0.2J
2J
23
22
4.1
14J
0.2.11
31
MW-04S
17-Nov-15
11
1,150
7.4
0.6J
24
36
140
56
15J
1.3.11
127
396
MW-04S
4-Oct-16
0.30J
1,OOO113
1.8
0.69JD
8.OJD
35D
69D
14
19JD
0.42.11
30D
91D
MW-04S
27-Apr-17
150
2.1J
1.6J
0.37.1
2.6.11
4.1J
MW-04S
3-Oct-17
900
0.18J
24
14
0.47J
16
1.7.11
9.5.1
MW-04S (dissolved)
3-Oct-17
NA
NA
960
NA
NA
NA
29
NA
NA
NA
NA
NA
NA
NA
MW-04S
19-Apr-18
0.60J
590
0.15J
11
15
0.43J
7.9.1
5.2J
MW-04S (dissolved)
19-Apr-18
NA
NA
NA
NA
NA
NA
10
NA
NA
NA
NA
NA
NA
NA
NA
MW-04S
4-Oct-18
410
9.2J
23
6.2.1
4.2.1
MW-04S (dup)
4-Oct-18
400
8.8J
23
5.9.1
4.6.1
MW-04S (dissolved)
4-Oct-18
NA
NA
NA
NA
NA
NA
8.4.11
NA
NA
NA
NA
NA
NA
NA
NA
MW-04S (dup dissolved)
4-Oct-18
NA
NA
NA
NA
NA
NA
7.9J
NA
NA
NA
NA
NA
NA
NA
NA
MW-04S
17-Apr-19
680
0.16J
1.613J
16
13
1.4J
10J
1.5.1
13
MW-04S (dissolved)
17-Apr-19
NA
NA
NA
NA
NA
NA
16
NA
NA
NA
NA
NA
NA
NA
MW-04S
5-Sep-19
890
0.22J
30
9.4
0.32J
19
9.913J
MW-04S (dissolved)
5-Sep-19
NA
NA
960
NA
NA
NA
32
NA
NA
NA
NA
NA
NA
NA
NA
MW-4S
22-Apr-20
850
0.34J
1.7J
32
29
18
1.5J
5.91
MW-4S (dissolved)
22-Apr-20
NA
NA
890
NA
NA
NA
33
NA
NA
NA
NA
NA
NA
NA
NA
CDM_
Smith
IDIMPage 2 of 3 Alternate Source Demonstration

Table 1
Detected Groundwater Constituents - Metals
East Wake Landfill - Area D
Facility Permit No. 9202-MSWLF-1981
MW-04D
22-Oct-14
0.6J
660
25
6.1
21J
3.1
413J
MW-04D
13-May-15
0.8J
960
2
0.3J
19
40
103
23
25J
0.51
61
173
MW-04D
4-Oct-16
0.28J
0.76J
880D
0.28J
0.33.1
1.8J
21
19
2.0.1
18J
7.7J
29
MW-04D
27-Apr-17
3.5.1
940
17
17
1.4J
9.7.1
3.9.1
6.9J
28
MW-04D
3-Oct-17
0.78J
730
10
8.7.1
0.66.1
13J
2.5J
MW-04D (dissolved)
3-Oct-17
NA
NA
730
NA
NA
NA
11
NA
NA
NA
NA
NA
NA
NA
MW-04D
19-Apr-18
840
0.15J
15
20
14J
4.8.1
MW-04D (dissolved)
19-Apr-18
NA
NA
770
NA
NA
NA
15
NA
NA
NA
NA
NA
NA
NA
NA
MW-04D
4-Oct-18
880
8.4J
13
13J
1.3.1
4.2.1
MW-04D (dissolved)
4-Oct-18
NA
NA
940
NA
NA
NA
8.0.1
NA
NA
NA
NA
NA
NA
NA
NA
MW-04D
17-Apr-19
4.2J
1,500
0.25J
0.20J
1.913J
23
18
1. 1.1
191
7.5J
15
MW-04D (dissolved)
17-Apr-19
NA
NA
790
NA
NA
NA
28
NA
NA
NA
NA
NA
NA
NA
MW-04D
5-Sep-19
860
18
7.8
0.61J
17
12B
MW-04D (dissolved)
5-Sep-19
NA
NA
790
NA
NA
NA
17
NA
NA
NA
NA
NA
NA
NA
NA
MW-4D
22-Apr-20
770
26
20
21
1.7J
4.OJ
MW-4D (dissolved)
22-Apr-20
NA
NA
770
NA
NA
NA
26
NA
NA
NA
NA
NA
NA
NA
NA
MW-07
22-Oct-14
5013J
0.4.1
0.2J
0.91
0.3J
15B
MW-07
13-May-15
150
3
0.7J
10
6J
14
12
3.1
0.3J
13J
29
MW-07
4-Oct-16
150
3.5
0.071J
7.OJ
3.4J
7.3.1
7.5.1
1.4.1
0.24J
18J
21
MW-07
27-Apr-17
93J
1.1
2.2J
2.3.1
1.3.1
5.4J
11
MW-07
3-Oct-17
140
2.2
0.67J
6.5J
3.6J
7.9.1
6.3.1
1.6J
0.17J
18J
28
MW-07 (dissolved)
3-Oct-17
NA
NA
NA
NA
NA
NA
1.7J
NA
NA
NA
NA
NA
NA
1.6J
NA
MW-07
19-Apr-18
96J
1.5
3.0
3.5.1
2.5J
2.8.1
2. 1.1
5.OJ
16
MW-07 (dissolved)
19-Apr-18
NA
NA
NA
NA
2.6
NA
1.6J
NA
NA
NA
NA
NA
NA
NA
MW-07
4-Oct-18
84J
0.78.1
1.91
1.8J
8.4.1
MW-07 (dissolved)
4-Oct-18
NA
NA
NA
NA
NA
NA
1.7J
NA
NA
NA
NA
NA
NA
NA
NA
MW-07
17-Apr-19
86J
1.0
1.4
4.113J
1.7J
4.2.1
3. 1.1
33
MW-07 (dissolved)
17-Apr-19
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-07
17-Sep-19
68
0.84
1.4
2.OJ
1.51
2.8.1
1.1
2.6J
44B
MW-07 (dissolved)
17-Sep-19
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
MW-07
22-Apr-20
68
0.83
0.53
1.4.11
1.7
0.81J
23
MW-07 (dissolved)
22-Apr-20
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Notes:
1. All units are in micrograms per liter (parts per billion).
2. * - Interim Maximum Allowable Concentration (IMAC)
3. dup - Duplicate Sample
4. J - Indicates the analytical result is an estimated concentration between the method detection limit and the limit of quantitation.
5. B - The analyte concentration detected in the method blank was greater than the method detection limit.
6. D - Indicates the sample was analyzed at a dilution greater than 1.
7. Dissolved metals samples were collected to evaluate the influence of turbidity on total metal concentrations as part of an ongoing Alternate Source Demonstration.
8. NA - Not Analyzed
- Concentration exceeds the North Carolina 2L or IMAC Standard
- Indicates the result is below the detection limit
_ CDM
Smith
DM. Page 3 of 3 Alternate Source Demonstration

Table 2
Proposed Site -Specific Upper Tolerance Limits
East Wake Landfill
Facility Permit No. 9202-MSWLF-1981
Notes:
1. All units are in micrograms per liter (parts per billion).
2. UTL - Upper Tolerance Limit
3. NC 2L - 15A NCAC 02L .0202
4. * - Interim Maximum Allowable Concentration (IMAC)
5. KM - Kaplan -Meier Upper Tolerance Limit Method
6. NP - Non -Parametric Prediction Limit Method
7. NA - Not Applicable
Proposed Site -Specific UTL
CDM Page 1 of 1 Alternate Source Demonstration
Smith

♦
�0
MW-02
242.22 r
N
r
•._
MW-03 ro
231.69 c
a
Area D
MW-04S
229.20
MW-04D
229.47
t-:
r i
w
t MW-07
248 903
I_ MA
T
,II
\aa� I
Carolyn Properties, LLC
(J.T. Knorr PropertyO
I l:
LEGEND
II Groundwater Monitoring,
/fY^I e4ise Groundwater Elevatiorn ' I
Potentiometric Contour
240 — COlto rtnrenal IL to I"[
(aasaan.nea inferred)
----Property Line

Appendix A
Statistical Analyses

Appendix B
Statistical Analyses - ProUCL Notes
Notes:
1. Data analyses were completed using the U.S. Environmental Protection Agency's ProUCL 5.1 (ProUCL) software.
2. Select analytes from the background monitoring well (i.e. MW-01) was evaluated statistically to create new upper tolerance levels (UTLs).
3. The data table shows the format used in the ProUCL software. All detections are in parts per billion.
4. Data for non -detects are provided in two colums. The first column has the value of the detected observation as reported, or half of the reporting limit for non -detects. The
second column represents the detection status, '0' for non -detect and '1' for detect. The header representing the detection status column is shown as 'D_Analyte'
(e.g. D_Chromium, D_Vanadium). This is how the program takes non -detects into account when running analyses.
5. Goodness -of -fit tests were completed for each analyte. Graphs showing the goodness -of -fit are shown under the data table. Normality and percent non -detects
determined which analyses to use. No graphs are shown for wells with less than 3 detections.

East Wake
MW-01 Statistical Analyses
Date
Turbidity
1
2
3
Well ID
Barium
D Barium
26-Apr-11
25
MW-01
134
1
29-Sep-11
0
M W-01
114
1
26-Mar-12
3
MW-01
139
1
26-Mar-13
2
MW-01
149
1
9-Oct-13
0
MW-01
130
1
25-Mar-14
1
MW-01
120
1
22-Oct-14
0
MW-01
120
1
15-Jan-18
10
MW-01
120
1
19-Apr-18
31
MW-01
120
1
22-Apr-20
19
MW-01
120
1
Percent Non -Detects
Normal Q-Q Plot (Statistics using Detected Data) for Barium
Theoretical Quandles (5tandard Normal)
0%
Item=126.6
T-
hwa.-TwrtSYc-o.&a
Barium
Kaplan -Meier Upper Tolerance Limit
Group
Observed
Mean
UTL
MW-01
10
126.6
158.8

East Wake
MW-01 Statistical Analyses
Date
Turbidity
1
2
3
Well ID
Cobalt
D Cobalt
26-Apr-11
25
MW-01
2.96
1
29-Sep-11
0
MW-01
0.65
0
26-Mar-12
3
MW-01
0.65
0
26-Mar-13
2
MW-01
0.2
1
9-Oct-13
0
MW-01
0.1
1
25-Mar-14
1
MW-01
0.05
1
22-Oct-14
0
MW-01
0.06
1
4-Oct-16
87
MW-01
0.61
1
3-Oct-17
35
MW-01
0.65
0
15-Jan-18
10
MW-01
0.65
0
26-Feb-19
94
MW-01
0.65
0
5-Sep-19
85
MW-01
1.9
1
22-Apr-20
19
MW-01
0.65
0
Percent Non -Detects
50%
Normal Q-Q Plot for Cobalt
�' I
Statistics using ROS Normal Imputed Estimates
_s
25
�a
gr --
�re
Theuretcal Quantles (Standard Narmall
Imputed Nye Displayed with Inverted Triangle
Cobalt
Kaplan -Meier Upper Tolerance Limit
Group
jObservedl
Mean
1
I UTL
MW-01
1 10
0.84
1 2.82

East Wake
MW-01 Statistical Analyses
Date
Turbidity
1
2
3
Well ID
Vanadium
D Vanadium
29-Sep-11
0
MW-01
1.25
0
26-Mar-12
3
MW-01
1.25
0
29-Sep-11
1 0
MW-01
1.25
0
26-Mar-12
3
MW-01
1.25
0
26-Mar-13
2
MW-01
1.25
0
9-Oct-13
0
MW-01
1.25
0
25-Mar-14
1
MW-01
2
1
22-Oct-14
0
MW-01
2
1
15-Jan-18
10
MW-01
1.25
0
22-Apr-20
19
MW-01
1.25
0
Percent Non -Detects 80%
Vanadium
Non -Parametric Prediction Limit
Group
Observed
Mean
UTL
MW-01
19
2
2

1200
0 1000
v
800
a
600
m
0.
= 400
0
= 0
O
U � Ln Ln Ln lD lD l0 r� r` r` 00 00 DD Ol Q1 01 O
U -0C *' -CC *' -OC +' -OC +' -OC +' -0
O LL - O LL - O LL - O LL - O LL - O LL
Date
MW-01 Barium
Dissolved Barium
MW-01 Vanadium
120
0 100
80
CL
L
60
i%
c 40
0
c�
20
a
u
= 0
O
U � Ln Ln Ln LD lD LD r` r` r` 00 W ao 61 01 Ol O
c-I r-I r-I c-I r-I r-I ci rl ri rl i--I �--I c-I ci rl ci N
O u_ � O LL 7O LL 7 O LL O LL O LL
Date
MW-02 Cobalt
Dissolved Cobalt
6
5
—a--cobalt
4
3
2
1
0
,j-
c-I
Ln
r-I
Ln Ln
r-I c-I
LD
r-I
.D lD
r-I ci
r,
rl
r- r,
ri rl
oo oo oo Ql of
i--I i--I c-I r-I r-I
Ql O
c-I N
O
LL
O
LL
O
-O
LL
C +'.'
O
-OC +.' -OC
a)
LL O LL
++ -0
U
O LL
Date
F-
Concentration Trend Graphs
MW-01 Cobalt
40
35
Dissolved Cobalt
30
+Cobalt
v 25
a
i 20
c�
15
_
0
10
L
c 5
a
U
= 0
O
U
IZT Ln
Ln Ln lD LD lO
r-
r- r-
00
w 00
M
M M O
O LL
-OC +'
- O LL O
-O
L L
C a'
� O
-O
L L
C a'
� O
s
LL
C }' -0
-
O LL
Date
MW-02 Thallium
0.7
Dissolved Thallium
c
0.6
+Thallium
0.5
L
L
LA
0.4
L
a
0.3
c
c
0.2
—
41
0.1
v
U
O
0
U
-�t Ln
r-I r-I
Ln Ln
r-I r-I
to to
r-I r-I
lD
r-I
r� r, r, 00 00 00 01 M 0) O
r-I r-I r-I r-I r-I r-I r-I rl ri N
a-+ -0
O LL
C
O
Mc:
LL
O
_or_ -CC Mc: -0
LL) O LL� O LL O LL
Date
►��M11UrN
3
0 2.5
a
2
o.
L 1.5
�a
a
= 1
0
0.5
_
a
U
= 0
O
c.i 'j- Ln Ln Ln LD lD lD r, r` r, 00 00 00 M M M O
r 1 —1 r-I - l ci r-I r-I r1 r-I r-I r1 ri r-I -1 r-I r-I N
30
0 25
20
a
15
m
a
= 10
0
Ln
5
_
a,
u
= 0
O
O LL 7 O LL_ 7 O LL 7 O u_ 7 O LL O LL
Date
MW-02 Vanadium
--M Dissolved Vanadium
U T Ln M Ln �D LD lD r- r- r- 00 00 00 M M M O
r 1 r-I r-I - l r-I r-I r-I r-I r-I r-I r-I r-I r-I i--I r1 i--I N
O LL O LL O LL O LL O LL O Li
Date
CDM
Smith Page 1 of 2 Alternate Source Demonstration

1400
c 1200
0
1000
L
Q- 800
0
V
a. 600
0 400
ca
200
c
v
c 0
O
U
1600
1400
0 1200
1000
a
800
a 600
c 400
L 200
0
u
C
O
U
7
c 6
O
5
L
°1
a 4
Y 3
c`a
a
c 2
_o
41
U
0
C
O
U
MW-04S Barium
rl ri ri rl ri rl ri c1 r-I r-I r-I r-I r-I rl ri rl N
U _Q C U w C U w C U s C U w C U w
O LL — O LL — O ii — O LL — O LL — O LL
- -1 -1 -'
Date
MW-04D Barium
Dissolved Barium
Barium
� u1 LI1 u1 lD lD l0 I� n n 00 00 W 01 Q1 Ol O
r-I r-I r-I rl ri ri rl ri rl ri ri ri ri rl ri ri N
O U- O LL O LL O LL O LL O ii
r-I �q
Date
MW-07 Cobalt
Dissolved Cobalt
—*—Cobalt
i
� Lfl In L.f1 lD lD lD I� N � 00 00 00 Ol Ol Ol 0
i i' - i i'3 iO iO LO UO LO LO i
Date
40
c 35
O
30
v 25
a
in
20
Q 15
° 10
m
L 5
c
a,
c 0
O
U
45
40
C
0 35
30
a 25
L 20
15
c
10
f0 5
c
a, 0
U
C
O
U
20
c
18
0 16
14
a, 12
a
Y 10
0 8
a
6
4
2
U
0
i
O
U
Concentration Trend Graphs
MW-04S Cobalt
v un Ln Ln lD LO (.D r, r- r, w w w M m M o
U -0C a-' -OC }' -OC }' -OC a-' -CC �-' -0
O LL O LL O LL O LL O LL O LL
Date
MW-04D Cobalt
Dissolved Cobalt
--n�-- Cobalt
� in i11 u") lD lD lD I� n � W W o0 a1 Ol dl O
r-I rl ri ri ri ri rl ri ri ri rl ri rl ri rl ri N
O LL O LL O LL O LL O LL O ii
Date
MW-07 Vanadium
� in u'1 u1 rD lD rD I� n n 00 00 00 Q1 01 Q1 O
r-I r-I r-I r-I r-I r-I r-I r-I r-I r-I r-I r-I r-I r-I r-I r-I N
O LL O LL O LL O LL O Li O
Date
140
c 120
O
100
L
Q- 80
M 60
0 40
ca
20
c
a,
c 0
O
U
70
c 60
O
50
a 40
30
c 20
0
L 10
c
�+ 0
U
C
O
U
MW-04S Vanadium
v Ln Ln un I'D lD �.O r- r- r, w w w M M M O
r-I r-I r-I rl ri ri rl ri ri rl ri ri rl ri rl ri N
*' ) C +' � C �' -0 C +' -0C +' C *' -0
O LL � O LL O LL � O ii - O LL O LL
Date
MW-04D Vanadium
.zT u1 M M (.D lD lD I- n r� W W w M M 0) O
r-I r-I r-I rl ri ri rl ri r-I r-I r-I r-I r-I r-I r-I r-I N
i
O LL O LL O LL O LL O LL O i
Date
CDM
Smith Page 2 of 2 Alternate Source Demonstration