9204_Sorrell_MSWLF_GWMR_20170412

April 2017
SEMI-ANNUAL MONITORING OF
GROUNDWATER AND SURFACE WATER
SORRELL LANDFILL
APEX, WAKE COUNTY, NORTH CAROLINA
(DWM Permit No. 92-04)
S&ME Project No. 1054-07-251

Prepared for:

Sorrell Grading Company
P.O. Box 100
Apex, North Carolina 27502

Prepared by:
3201 Spring Forest Road
Raleigh, North Carolina 27616

______________________________ _____________________________
Bryan S. Wence Samuel P. Watts, P.G.
Staff Professional Senior Project Manager

June 14, 2017
April 2017 Semi-Annual Monitoring S&ME Project No. 1054-07-251
Sorrell Landfill, Apex, North Carolina June 14, 2017

Table of Contents
Section Page
EXECUTIVE SUMMARY ............................................................................................1
1.1 BACKGROUND ................................................................................................................... 3
2.0 GENERAL PHYSIOGRAPHY ...........................................................................5
2.1 SITE TOPOGRAPHY ........................................................................................................... 5
2.2 REGIONAL GEOLOGY ........................................................................................................ 5
2.3 SITE GEOLOGY AND HYDROGEOLOGY ............................................................................ 6
2.4 GROUNDWATER TABLE .................................................................................................... 6
2.5 HYDRAULIC GRADIENT AND GROUNDWATER FLOW VELOCITY CALCULATIONS ........... 7
2.6 SURFACE WATER ............................................................................................................. 9
3.0 SAMPLING PROGRAM ....................................................................................10
4.0 FIELD PARAMETERS .......................................................................................11
4.1 SPECIFIC CONDUCTIVITY................................................................................................ 11
4.2 PH .................................................................................................................................... 11
4.3 TEMPERATURE ................................................................................................................ 12
4.4 TURBIDITY ....................................................................................................................... 12
5.0 ANALYTICAL RESULTS .................................................................................13
5.1 GROUNDWATER .............................................................................................................. 13
5.2 SURFACE WATER ........................................................................................................... 14
6.0 QUALITY CONTROL SAMPLES...................................................................15
7.0 STATISTICAL ANALYSIS ..............................................................................16
8.0 SUMMARY ............................................................................................................17
8.1 GROUNDWATER RESULTS .............................................................................................. 17
8.2 SURFACE WATER SAMPLES ........................................................................................... 18
9.0 RECOMMENDATIONS .....................................................................................19

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Table of Contents (Cont’d)

TABLES
TABLE 1: STATIC GROUNDWATER ELEVATIONS
TABLE 2: SUMMARY OF HYDRAULIC CONDUCTIVITY VALUES
TABLE 3: GROUNDWATER VELOCITY CALCULATIONS
TABLE 4: SUMMARY OF FIELD PARAMETERS
TABLE 5: DETECTED ANALYTES – APRIL 2017 SAMPLING EVENT

FIGURES
FIGURE 1: VICINITY MAP
FIGURE 2: GROUNDWATER POTENTIOMETRIC MAP

APPENDICES
APPENDIX I: LABORATORY REPORTS
APPENDIX II: HYDRAULIC GRADIENT / GROUNDWATER FLOW VELOCITY CALCULATIONS
APPENDIX III: SUMMARY TABLE OF ELECTRONIC DATA DELIVERABLE (EDD)

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EXECUTIVE SUMMARY

S&ME, Inc. (S&ME) was contracted by the Sorrell Grading Company and The Estate of
Mr. Clyde E. Sorrell, Senior, (Sorrell) to provide semi-annual groundwater and surface
water monitoring services at Sorrell Landfill located off of Smith Road (S.R 1303) near
Apex, North Carolina. This monitoring event was performed on April 12, 2017. These
services were performed in general accordance with the Water Quality Monitoring Plan
(WQMP) prepared in June 1996 by Trigon Engineering Consultants, Inc. as modified by
the request for additional sampling locations made by representatives of NCDEQ-DWM,
and NCDEQ’s Water Quality Monitoring Requirements Letter, dated April 29, 2003.
The landfill is currently in an assessment monitoring program because of the detection of
contaminants in monitor well samples in excess of North Carolina Groundwater
Protection Standards. Services conducted by S&ME for the April 2017 sampling event
were performed in general accordance with proposal no. P4258-07V, dated April 25,
2007 and the S&ME’s memorandum Cost Estimate for 2017 Semi-Annual Groundwater
and Surface Water Sampling Events, dated March 16, 2017.

During the April 2017 monitoring event, one background well (MW-1R), one deep and
four shallow compliance wells (DW-1, MW-5, MW-6, MW-8 and MW-9), one off-site
assessment well (GP-9) and two surface water sampling locations (SW-1 and SW-2) were
sampled. Based on groundwater elevations measured during the April 2017 sampling
event, the overall groundwater flow at the landfill is to the east-northeast at an average
velocity of 35.12 ft/yr. Deep well DW-1 was installed within the bedrock aquifer, near
MW-8 along the facility’s southern boundary, to delineate the vertical extent of landfill
contaminants that may be migrating from the landfill cell. However, a comparison of
groundwater elevations in DW-1 and MW-8 indicates that an upward gradient continues
to exist between the two water-bearing zones in the vicinity of these wells. Due to the
upward gradient in the vicinity of DW-1, contaminants are unlikely to migrate
downward. Current analytical data of groundwater quality at DW-1 supports this
assumption.

Groundwater and surface water samples were analyzed for constituents listed in 40 CFR
258, Appendix I Constituents for Detection Monitoring (Appendix I). In addition, the
groundwater samples from monitor wells MW-8 and GP-9 were also analyzed for the
Appendix II List of Hazardous Inorganic and Organic Constituents (Appendix II) for
assessment monitoring. The laboratory analytical results for the groundwater samples
were compared to the maximum allowable concentrations promulgated in the State of
North Carolina groundwater standards as presented in 15A North Carolina
Administrative Code, Subchapter 2L (15A NCAC 2L), hereafter referred to as the 2L
Standards, NCDEQ Solid Waste Section Limits (SWSLs) or the Solid Waste
Groundwater Protection Standards (GWP ST) established in accordance with the Solid
Waste Rules Section .1634(h). The surface water sample analytical results were
compared to the maximum allowable concentrations promulgated in the North Carolina
Surface Water Class C standards found in 15A NCAC 2B (2B Standards).

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From groundwater samples collected during the April 2017 sampling event, eight
constituents were detected at concentrations greater than their respective 2L Standards or
SWSL Standards: 1,2-dichloropropane, benzene, tetrachloroethene, trichloroethene, vinyl
chloride, cobalt, vanadium, and thallium.

During the April 2017 monitoring event none of the Appendix II organic constituents
were detected above the laboratory method detection limits (MDLs). The inorganic
constituents arsenic, barium, beryllium, chromium, cobalt, copper, lead, nickel,
vanadium, and zinc were detected above their MDLs in the sample from the upstream
(SW-1) surface water monitoring location. Cobalt, copper, lead, vanadium, and zinc
were detected in the downstream (SW-2) surface water sample. All organic constituents
were detected at concentrations below their respective surface water quality standards
(2B Standards).

The frequency and number of metals detected at the site have declined since low-flow
sampling procedures were implemented in 1999. It is recommended that the use of low
flow sampling methods be continued and that monitoring for inorganics be limited to
Appendix I inorganic constituents (no cyanide or sulfide) at the facility’s monitor wells
and surface water monitoring points.

VOCs have been detected in samples collected from well MW-8 since the well was
installed in 2001. The consistent detection of VOCs at MW-8 indicates that a source or
sources of VOCs may be present at or near this well. Additional assessment of
surrounding properties was conducted in October 2008 to further evaluate the extent of
the groundwater plume in the area of MW-8. VOCs were detected above the 2L
Standards in the off-site groundwater assessment monitor wells in October 2008 and
subsequent monitoring events. An assessment of corrective measures and corrective
action should be performed to address the groundwater contamination in the area of MW-
8. In the meantime, it is recommended that groundwater monitoring at MW-8 continue to
monitor for Appendix II VOCs. Sampling of the off-site assessment wells in the vicinity
of MW-8 (GP-9 and /or GP-10) should continue to be included as part of the regular
compliance monitoring to monitor the extent, movement and concentration of off-site
groundwater contamination.

S&ME recommends that semi-annual assessment monitoring of groundwater and surface
water be continued at the Sorrell Landfill. Currently, six monitor wells and two surface
water locations are sampled at Sorrell Landfill to fulfill the monitoring requirements as
required by North Carolina Solid Waste Management Rule .1634.

It is our understanding that the Wake County Department of Environmental Services,
Water Quality Division regularly samples the potable wells on the adjacent properties to
the south of the landfill (Dye and Herndon properties) as a precautionary measure to
protect the users of these potable wells. S&ME recommends the results of this sampling
event be provided to Wake County for consideration in deciding protective measures for
the potable wells and their users.
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1.0 INTRODUCTION
1.1 Background

S&ME, Inc. (S&ME) was contracted by the Sorrell Grading Company and The Estate of
Mr. Clyde E. Sorrell, Senior, (Sorrell) to provide groundwater and surface water
monitoring services at Sorrell Landfill located off of Smith Road (S.R 1303) near Apex,
North Carolina (Figure 1). The sampling for this monitoring event was completed on
April 12, 2017. The services were performed in accordance with the facility’s revised
Water Quality Monitoring Plan (WQMP) prepared in February 1996 by Trigon
Engineering Consultants, Inc. Section 4.0 of the WQMP outlined the sampling and
analysis plan (SAP) to be used to monitor groundwater and surface water in the vicinity
of the landfill. The landfill is currently in an assessment monitoring program because of
the detection of contaminants in monitor well samples at concentrations exceeding
groundwater standards.

In accordance with the approved WQMP, four baseline sampling events were performed
in May, June, July, and August 1999. During each of those sampling events,
groundwater samples were collected from two upgradient (background) wells (MW-1R
and MW-4), and three downgradient (compliance) wells (MW-5, MW-6, and MW-7). A
surface water sample was collected at one down-gradient surface water monitoring point
(SW-2). Groundwater and surface water samples collected during the four 1999
sampling events were analyzed for constituents listed in 40 CFR 258, Appendix I
Constituents for Detection Monitoring (Appendix I). The sample results and subsequent
statistical analyses performed for the 1999 sampling rounds constitute the baseline for the
semi-annual sampling events being conducted during the post-closure period. The
baseline sample results submitted to the North Carolina Department of Environmental
Quality, Division of Waste Management (NCDEQ-DWM) on April 9, 2001, indicated
that one or more constituents listed in Appendix I were detected at statistically significant
levels.

Based on the results of the baseline sampling events, assessment monitoring was
conducted at Sorrell Landfill during four subsequent sampling events (April 2001,
December 2001, April/May 2002, November 2002) for the constituents listed in 40 CFR
258, Appendix II List of Hazardous Inorganic and Organic Constituents (Appendix II) as
promulgated in Section .1634.

At the request of the DWM, beginning with the December 2001 sampling event and
continuing with the April/May 2002 and November 2002 events, S&ME also collected
groundwater samples from two new monitor wells- one shallow well (MW-8) and one
deep well (DW-1), installed along the facility’s southern property boundary. Both wells
are located approximately between the southern edge of the landfill cell and the closest
residential well. Based on measured monitor well water elevations obtained during
performance of the 2001 and 2002 sampling events, and potentiometric mapping of the
shallow aquifer, it appears that monitor wells DW-1 and MW-8 may be hydraulically
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upgradient of the landfill. However, for the purposes of this report, wells MW-8 and
DW-1 are reported as compliance wells.

Following the November 2002 sampling event, S&ME recommended revising the
number of sampling locations, the sampling frequency, and the laboratory analysis
performed at each sampling location. In a letter dated April 23, 2003, the Section
approved these revisions. Based on the revised monitoring plan, one background well
(MW-1R), five compliance wells (DW-1, MW-5, MW-6, MW-7, and MW-8), and two
surface water locations (SW-1 and SW-2) were to be monitored. Subsequently, S&ME
determined that monitor well MW-7 was located either in or immediately adjacent to the
landfill wastes. Therefore, S&ME requested, on behalf of the owners, that the sampling
of MW-7 be suspended and that a new compliance well be installed in that area. In a
letter dated May 10, 2004, the Section concurred with that opinion. Monitor well MW-9
was installed on September 18, 2007 and has replaced MW-7 as the compliance well
along the northern portion of the landfill. Well MW-7 remains in place for measuring
water levels.

This report presents the methods used and the results of the sampling event conducted by
S&ME during the April 2017 sampling event at the facility which included the sampling
of one background well (MW-1R), one deep and four shallow compliance wells (DW-1,
MW-5, MW-6, MW-8 and MW-9), one off-site assessment well (GP-9) and two surface
water sampling locations (SW-1 and SW-2).

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2.0 GENERAL PHYSIOGRAPHY

Some of the general background information presented in this section has been compiled
from the Water Quality Monitoring Plan prepared in June 1996 by Trigon Engineering
Consultants, Inc.; from the Preliminary Explanatory Text for the 1985 Geologic Map of
North Carolina (1988) prepared by The North Carolina Geological Survey; and from
Geology of the Carolinas (1991) by Horton and Zullo. The information presented herein
has been modified for brevity and is intended to provide general background information,
particularly in regards to regional topography, geology, and hydrogeology.

2.1 Site Topography

The landfill site is located southeast of Apex, North Carolina in southwestern Wake
County (Figure 1). At its highest point, the landfill extends approximately 30 to 45 feet
in elevation above the surrounding natural ground surface. The natural ground surface
elevations at the site prior to construction of the landfill ranged from 400 to 460 feet
above Mean Sea Level (MSL). The current landfill cap surface slopes gently downward
to the southwest to an approximate elevation of 490 feet above MSL (Figure 2).

2.2 Regional Geology

The site is located in the eastern portion of the Piedmont physiographic province. In
Wake County, the land surface is evenly divided between flat to gently rolling inter-
stream areas and valleys. Soils and weathered rock typically extend downward to depths
up to 60 feet below ground surface (bgs). Outcrops of hard bedrock are rare and most are
confined to streambeds and excavations.

Bedrock at the site area has been characterized as part of the Carolina Slate Belt. The
Carolina Slate Belt in this portion of the county consists primarily of predominately low-
grade felsic metavolcanic and meta-epiclastic rocks, presumed to have originated from a
sub-aqueous, volcanic arc environment. Primary rock types include metamorphosed
argillites, mudstone, volcanic sandstone, and conglomerate. Approximately one-half
mile to the west, an unconformity identified as the Jonesboro Fault separates the Carolina
Slate Belt from Triassic claystone and siltstone sediments.

Cretaceous-age Coastal Plain sediments immediately overlie the basement rocks in the
southern and eastern portion of the site. Middendorf units include deposits of sand,
sandstone, and mudstone. Beds are laterally discontinuous with inter-fingering cross-
bedding common in the upper units.

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2.3 Site Geology and Hydrogeology

The site lies on the western edge of the Neuse River basin. Surface water run-off from
the site flows to the west into Middle Creek. Surface water then flows to the south and
east toward the confluence of Middle Creek and the Neuse River near Smithfield, NC.

The unconfined aquifer in western Wake County is typically present in the
unconsolidated subsurface residual soils to an approximate depth of 30 feet bgs,
depending on the topography. Shallow groundwater flow patterns in the vicinity of the
landfill have been evaluated through a series of shallow downgradient monitor wells
finished at depths ranging between approximately 14 to 27 feet bgs and approximately 45
feet bgs in an upgradient well (MW-1R). The depth to groundwater varies from just
below the ground surface in the downgradient wells located on the western side of the
landfill to approximately 34 feet bgs on the eastern (upgradient) side of the landfill at
MW-1R.

A nested well pair, one shallow well (MW-8) and one deep well (DW-1) is
approximately located between the edge of the landfill cell and the closest residential
wells installed along the facility’s southern property boundary line (Figure 2). The
shallow monitor well (MW-8) was installed into the overlying sandy silt and is believed
to monitor the same shallow unconfined aquifer monitored by the other wells previously
installed at the site. Monitor well DW-1 is the only well installed into the bedrock
aquifer at the site.

At the location of DW-1, the soil immediately beneath the ground surface was classified
as sandy silt and silt to a depth of approximately 54 feet bgs. Underlying the sandy silt
and silt is partially weathered metavolcanic and metasedimentary rock of various degrees
of weathering, extending to approximately 66 feet bgs, where more competent bedrock
was encountered. The underlying competent rock is bluish schist with quartz, muscovite,
biotite, and hornblende minerals, and was observed to a depth of 101 feet bgs, where the
deep boring was terminated.

During drilling activities, water-bearing fractures were observed in the bedrock at 78 feet
bgs and 99 feet bgs. Based on field estimates by S&ME, the water-bearing zone at 78
feet bgs produced approximately one gallon per minute (gpm) and the water-bearing zone
at 99 feet produced approximately six gpm.

2.4 Groundwater Table

Prior to sampling for this monitoring event, each well was examined for its general
integrity, including protection from surface water inflow, well identification tag, vented
cap, lock, and general well security. Each well was opened and the depth to the water in
the well was measured from a referenced mark on the top of the PVC well casing using
an electronic water level indicator. The water elevation at each well was calculated by
subtracting the depth measurement from the elevation of the referenced top of casing.
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Table 1 shows the depth to groundwater measurements and groundwater elevation
calculations for each of the monitor wells sampled during the April 2017 sampling event
and the groundwater elevation calculations at each of the methane monitor wells.

The shallow groundwater is defined in this report as the water-bearing zone located in the
soil regime beneath and in the vicinity of the landfill. The depth to the shallow
groundwater was measured in the background wells (MW-1R, MW-4) and in the
compliance wells (MW-5, MW-6, MW-7, MW-8 and MW-9) during the sampling event.
Depth to groundwater was also measured in the deep well DW-1. However, this well is
believed to monitor a separate water-bearing zone within the bedrock aquifer and is not
representative of the shallow groundwater. In addition to the depth-to-water
measurements taken at these groundwater monitor wells, depth-to-water measurements
were also taken at thirteen groundwater monitor wells (GP-7, GP-7D,GP-8, GP-9, GP-10,
GP-10D, GP-11, GP-12, GP-12D, GP-13, GP-14, GP-15 and GP-16) installed along the
southern boundary of the landfill that were used to assess groundwater contamination in
the vicinity of MW-8 and methane gas monitor wells to supplement the water elevation
data. A complete list of monitor wells and methane gas monitor wells with the associated
groundwater elevation calculation is presented on Table 1.

2.5 Hydraulic Gradient and Groundwater Flow Velocity Calculations

The well water elevations and our interpretation of the water table surface expressed as a
potentiometric map along with groundwater flow direction are shown on Figure 2.
Based upon the groundwater elevations in the vicinity of the landfill cell, groundwater in
this area is projected to flow north-northwest toward an unnamed tributary of Middle
Creek, which is consistent with previous groundwater data.

Hydraulic Gradient
The average horizontal hydraulic gradient was calculated from three point calculation
solutions using two well sets of groundwater elevation data measured during the April 12,
2017 sampling event and by applying the following equation (Driscoll, 1986):

i = h1 - h2
L
Where:
i = Hydraulic gradient
h1 - h2 = Difference in hydraulic head (feet)
L = Distance along flow path (feet)

The three point calculation is used to estimate the hydraulic gradient perpendicular to a
groundwater potentiometric contour of equal elevation determined from high,
intermediate and low groundwater elevations at three monitor wells. The gradient
calculated perpendicular to the equal elevation contour plotted from the well set is
representative of a true gradient rather than the apparent gradient that is estimated from a
two point gradient calculation. Based on the Driscoll gradient equation and using a third
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groundwater elevation to plot the equal elevation contour, the distance L can be measured
between h1 and h2 perpendicular to the equal elevation contour to estimate the true
hydraulic gradient for the three groundwater elevation data points. The average
horizontal hydraulic gradient from two three point solutions using well sets MW-1R,
MW-9, and MW-4, and MW-8, MW-5 and MW-6 is estimated to be 0.028 ft/ft. This
gradient is similar to the hydraulic gradient previously calculated for the site. The
hydraulic gradient calculations are included in Appendix II.

Groundwater Flow Velocity
An approximate average linear groundwater flow velocity (v) may be calculated by the
equation (Freeze and Cherry, 1979):

v = Ki
n

Where:
v = Average linear groundwater flow velocity [feet per day (ft/day)]
K = Hydraulic conductivity (ft/day)
i = Flow gradient as a ratio (ft/ft),
n = Effective soil porosity (percent)

Aquifer slug tests were previously performed in monitor wells MW-6, MW-7, MW-8,
MW-9 and DW-1 at the site by S&ME using rising and falling head test techniques. The
slug test data were used to estimate the hydraulic conductivity of the sediments in the
surficial aquifer intersected by the screened intervals of the monitor wells tested. The
aquifer test data were analyzed by the Bouwer and Rice Method. As summarized on
Table 2, the average hydraulic conductivity values previously measured at the site ranged
from 4.00x10-4 centimeters per second (cm/sec) to 1.86x10-4 cm/sec.

The groundwater flow velocity was calculated for the site using the average hydraulic
conductivity values measured at the site; the average hydraulic gradient of 0.028 ft/ft,
calculated from the three point calculation described above; and an effective porosity of
20%. Groundwater flow velocities calculated during the April 2017 sampling event
ranged from 28.45 feet per year (ft/yr) between monitor wells MW-8 and MW-5 to 43.36
ft/yr between monitor wells MW-1R and MW-9. Calculations performed using the
equation and input values above estimate the average groundwater flow velocity for the
site was approximately 35.12 ft/yr. This velocity is similar to previous groundwater
velocities calculated for the site. The calculated hydraulic gradients and groundwater
flow velocities are presented in Table 3.

As previously discussed, monitor wells MW-8 and DW-1 were installed in December
2001 along the facility’s southern boundary based on hydrologic data available at the
time and the relative position of the landfill and the nearby potable wells. Monitor well
MW-8 was intended to serve as a point of compliance between the landfill and residential
wells installed adjacent to the site’s southern property boundary. However, as shown on
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Figure 2, static water levels measured during the April 2017 sampling event indicate that
MW-8 may be located hydraulically upgradient of the landfill cell.

DW-1 is the only well installed on site within a separate water-bearing zone contained
within the bedrock aquifer, and was installed to delineate the vertical extent of landfill
contaminants that may be migrating from the landfill cell. As shown on Table 1, the
groundwater elevation in DW-1 was observed to be 2.92 feet higher than the groundwater
elevation in MW-8 during the April 2017 sampling event. This difference in
groundwater elevations, representing hydraulic head, indicates that an upward gradient
exists between the two water-bearing zones in the vicinity of these two wells. This
upward flow component has been observed at these two wells since they were installed in
December 2001.

2.6 Surface Water

The site is located just south of an unnamed tributary that flows southwest into Middle
Creek. Middle Creek flows to the southeast, eventually emptying into the Neuse River
near Smithfield, North Carolina. The unnamed tributary is the only surface body to
receive surface water runoff from the landfill. S&ME selected two surface water
collection points along the unnamed tributary. One sample collection point (SW-1) is
located hydraulically upgradient from the landfill. The other sample collection point
(SW-2) is located hydraulically downgradient from the landfill. During the April 2017
sampling event surface water samples were collected from both sample locations.
Surface water sample collection points SW-1 and SW-2 are shown on Figure 2.
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3.0 SAMPLING PROGRAM

In accordance with 15A NCAC 13 B, § .1632, and the approved groundwater and surface
water SAP for the facility, the following sections describe the procedures used for the
collection of groundwater and surface water samples during the sampling event.

S&ME sampled surface water from the up-gradient and down-gradient collection points
along an unnamed tributary of Middle Creek (SW-1 and SW-2), one background well
(MW-1R), four shallow and one deep compliance wells (MW-5, MW-6, MW-8, MW-9
and DW-1) on April 12, 2017. One shallow off-site groundwater assessment well (GP-9)
was also sampled during the April 2017 sampling event. The monitor wells at the landfill
were sampled using a low-flow peristaltic pump equipped with polyethylene tubing.
Prior to sampling each of the wells, the groundwater was purged at a rate of
approximately 150 milliliters per minute until the turbidity was reduced to less than 10
Nephelometric Turbidity Units (NTUs) where it was achievable. Stabilization of the
selected field parameters was defined as a variance of less than 10 percent in three
successive readings recorded two minutes apart. Monitor well MW-1R was sampled
with a polyethylene bailer due to an increased depth-to-water.

The surface water samples from the creek were collected using laboratory-supplied 1-liter
bottles dipped directly into the stream as collection devices. The water was then poured
into laboratory-prepared vials and bottles.

At the completion of sampling, S&ME delivered the samples to Environmental
Conservation (ENCO) Laboratories in Cary, North Carolina for analysis according to the
following:

 MW-1R, MW-5, MW-6, MW-8, MW-9, DW-1, SW-1, and SW-2 were analyzed
for constituents listed in Appendix I (40 CFR 258); and
 MW-8 and GP-9 were analyzed for constituents listed in Appendix II (40 CFR
258).

Laboratory analytical methods for Appendix I constituents included EPA Method
6010C/6020A (metals) and Method 8260B volatile organic compounds (VOCs).

Laboratory analytical methods for Appendix II constituents included the Appendix I
constituent list, plus Method 8270D (SVOCs), Method 7470A (mercury), Method 9014
(cyanide) and SM18 4500-S D (sulfide). The analytical results reported from this
sampling event are discussed in subsequent sections of this report.
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4.0 FIELD PARAMETERS

Specific conductivity, pH, temperature, dissolved oxygen, oxygen reduction potential and
turbidity were measured in the field during well purging prior to sample collection. The
normal sampling protocol includes purging the shallow monitor wells with a peristaltic
pump at a rate of approximately 150 milliliters per minute until the turbidity is reduced to
less than 10 NTUs and the selected field parameters stabilize. Field parameters recorded
just prior to collecting the groundwater samples are summarized in Table 4 and discussed
in the following sections.

4.1 Specific Conductivity

Specific conductivity (conductance) is a measurement of the ability of a solution to pass
an electrical current. Dissolved inorganic anions and cations such as chloride, nitrate,
sulfate, phosphate, sodium, calcium, aluminum, and iron increase the ability of water to
carry a current. Conductivity is therefore related to the amount of total dissolved solids
in the water. Waters percolating through a landfill cell typically become enriched with
dissolved solids, which are reflected by increased conductivity values. Typically,
specific conductivity measures the presence of common ions such as chloride and sulfate
that are not necessarily indicative of hazardous constituents.

During the April 2017 sampling event, the specific conductance measured in the
background well (MW-1R) was 0.024 milliSiemens per centimeter (mS/cm).
Measurements in the four shallow compliance wells (MW-5, MW-6, MW-8, and MW-9)
ranged from 0.034 mS/cm (MW-9) to 0.085 mS/cm (MW-5). The specific conductance
measured in the off-site monitoring well (GP-9) was recorded as 0.029 mS/cm. The
specific conductance measured in the deep compliance well (DW-1) was recorded as
0.057 mS/cm. The highest groundwater conductivity value (0.0.085 mS/cm) was
measured in well MW-5. In general, conductivity readings are within the typical range of
values that would be expected to occur in shallow groundwater flow under natural
conditions in the Eastern Piedmont region.

4.2 pH

The pH is a measurement of the hydrogen ion concentration. Values lower than pH=7
indicate increasingly acidic conditions and values higher than pH=7 indicate increasingly
alkaline conditions. The pH may strongly influence the activity of certain chemical
reactions and the solubility and mobility of metals.

The pH of the groundwater in the landfill wells was measured just prior to sample
collection. The pH reading in the background well (MW-1R) was measured as 3.76. The
pH measured in the four shallow compliance wells ranged from 4.04 (MW-8) to 5.82
(MW-6). The pH values are within the range that would be expected for shallow
groundwater conditions in the Eastern Piedmont region. The pH measured in the off-site
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12
monitoring well (GP-9) was recorded as 3.86. The pH measured in the deep compliance
well (DW-1) was recorded as 4.10.

4.3 Temperature

Groundwater temperature collected from the background well was 16.75ºC (MW-1R).
Groundwater temperatures recorded from samples collected from four shallow
compliance wells ranged from 15.64ºC (MW-6) to 19.46ºC (MW-8). Temperature
measured from the deep compliance well (DW-1) was 18.37 ºC. Temperature measured
from the off-site assessment well (GP-9) was 18.77 ºC. Where the aquifer is in close
proximity to the ground surface, groundwater temperatures may be closely related to
seasonal temperature variations and the presence or absence of vegetative ground cover.

Groundwater temperature directly affects the solubility of oxygen and other geochemical
constituents. The solubility of dissolved oxygen is temperature-dependent, with oxygen
being more soluble in cold water than in warm water.

Groundwater temperature also affects the metabolic rate of bacteria. Rates of
biodegradation almost double for every 10 ºC increase in temperature between 5 ºC and
25 ºC. Elevated temperatures may also be an indication of significant microbiological
activity.

4.4 Turbidity

Nephelometric turbidity was added to the list of field parameters for selected wells after
the May 1999 sampling event detected higher than expected concentrations of metals.
Because the samples collected from monitor wells MW-1R and MW-6 during the initial
baseline sampling event were turbid, it was suggested that suspended soil particles
present in the groundwater could have contributed to elevated concentrations of metals
reported by the laboratory. Therefore a turbidity value of 10 NTUs was established as a
goal to achieve while purging and prior to collection of samples. During the April 2017
sampling event, the target value of 10 NTUs was not achieved in monitor well MW-1R
and in monitor well MW-6. Groundwater turbidity recorded just prior to sample
collection in the four shallow compliance wells ranged from 1.1 NTUs (MW-8) to 13.2
NTUs (MW-6). The turbidity level measured in the deep compliance well (DW-1) was
recorded as 0.4 NTUs. The turbidity level measured in the off-site assessment well (GP-
9) was recorded as 1.7 NTUs.

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5.0 ANALYTICAL RESULTS

S&ME sampled one upgradient (background) well; four shallow and one deep
downgradient (compliance) wells; two surface water locations; and one off-site
groundwater assessment well on April 12, 2017. The samples were analyzed by ENCO
Laboratories for constituents listed in Appendix I of 40 CFR 258. The groundwater
sample from compliance well MW-8 and the off-site assessment well GP-9 were
additionally analyzed for Appendix II SVOCs, mercury, cyanide and sulfide. Laboratory
analytical methods included EPA Method 6010C/6020A (metals), Method 8260B
(VOCs), Method 8270D (SVOCs), Method 7074A (mercury), Method 9014 (cyanide),
and SM18 4500-S D (sulfide). The analytical results for the groundwater and surface
water samples collected and analyzed in April 2017 are detailed below. A copy of the
analytical laboratory report is provided in Appendix I.

5.1 Groundwater

Groundwater sample analytical results were compared to North Carolina groundwater
standards as presented in 15A North Carolina Administrative Code, Subchapter 2L (15A
NCAC 2L), hereafter referred to as the 2L Standards and the Solid Waste Groundwater
Protection Standards (GWPST) established in accordance with the Solid Waste Rules
Section .1634(h). The analytical results for the April 2017 sampling event are
summarized on Table 5. Appendix III includes a summary table of the electronic data
deliverable (EDD) of the analytical and field data for the April 2017 sampling event.

From groundwater samples collected during the April 2017 sampling event, nine
constituents were detected at or above the reporting limits established by the Solid Waste
Section (SWSLs). The SWSL has little regulatory significance, except that it is a
minimum reporting limit. For several constituents, the SWSL is greater than the
corresponding North Carolina Groundwater Protection Standard.

For the April 2017 sampling event, eight constituents were detected at concentrations
greater than their respective 2L Standards, or GWPSTs: 1,2-dichloropropane (1.5 µg/L at
MW-8), benzene (10 µg/L at MW-8), tetrachloroethene (50 µg/L at MW-8),
trichloroethene (19 µg/L at MW-8), vinyl chloride (9.3 µg/L in MW-8), cobalt (4.34 µg/L
at MW-8, 11.8 µg/L at MW-9), vanadium (5.79 µg/L in MW-6), and thallium (0.498
µg/L at MW-8, 0.342 µg/L at GP-9, and 0.327 µg/L at DW-1). The laboratory analytical
results indicated that the concentrations of cobalt reported from MW-8; vanadium
reported from MW-6; and thallium reported from MW-8, MW-9, and DW-1; were below
their respective laboratory reporting limits. Constituents reported at concentrations
below the reporting limit are flagged with a “J” and are considered to be an estimate. It is
important to note that the laboratory method detection limit (MDL) for vinyl chloride is
0.32 µg/L which is greater than the 2L Standard of 0.03 µg/L. Therefore, vinyl chloride
may have been present at concentrations above the 2L Standard but reported below the
MDL.
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Appendix III includes a summary table of the electronic data deliverable (EDD) of the
analytical and field data for the April 2017 sampling event.
5.2 Surface Water

The surface water samples were compared to the North Carolina Class C surface water
standards as promulgated in 15A NCAC 2B (2B Standards). The surface water sample
results for the April 2017 sampling event are summarized in Table 5.

Of the organic constituents analyzed, none were detected at concentrations above their
respective MDLs from the surface water samples collected during the April 2017
sampling event.

The inorganic constituents arsenic, barium, beryllium, chromium, cobalt, copper, lead,
nickel, vanadium, and zinc were detected above their MDLs in the sample from the
upstream (SW-1) surface water monitoring location during the April 2017 monitoring
event. Barium, cobalt, copper, and thallium were detected in the downstream (SW-2)
surface water sample location in April 2017. The inorganic constituents cobalt, copper,
lead, vanadium, and zinc were detected above their respective 2B Standards in the sample
collected from the upstream SW-1 location. The inorganic constituents copper and
thallium were detected above their respective 2B Standards in the sample collected from
the downstream SW-2 location. However, the copper and thallium concentrations in the
sample collected from the downstream SW-2 location were reported with a “J” laboratory
qualifier indicating that the values are estimated concentrations below the lowest
calibration point.

Detected inorganic constituent concentrations from the upstream sample SW-1 were at
historic high levels. At the time of sample collection, the water level in the stream was
very low causing high levels of sediment to be disturbed and collected into the sample
containers. It is S&ME’s opinion that the high turbidity (47.3 NTUs) of the sample
collected from the SW-1 location attributed to the historic high concentrations of
inorganic constituents.
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6.0 QUALITY CONTROL SAMPLES

Quality control samples are required by the WQMP to demonstrate consistency of the
laboratory analytical processes and field sampling methods.

During the April 2017 sampling event, in addition to the groundwater sample collected
from monitor well DW-1 and identified as DW-1 on the chain-of-custody (record
sample), a blind duplicate sample was also collected from monitor well DW-1 (duplicate
sample). As shown on Table 5, similar analytes were detected in the record sample and
the duplicate sample.

Additionally, to assess the efficacy of the field equipment decontamination procedures,
an equipment rinse sample was taken by dipping the probe of the decontaminated water
level meter into a laboratory supplied bottle of deionized water. The equipment blank
sample was analyzed for the full Appendix I analyte list. The inorganic constituent
copper was reported with a “J” laboratory qualifier indicating that the value is an
estimated concentrations below the lowest calibration point. No other constituents were
detected above the laboratory’s method detection limit (MDL). The results of the quality
control sampling are presented with the analytical results in Appendix I of this report.

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7.0 STATISTICAL ANALYSIS

Previous monitoring reports submitted to the Section for this facility have included a
statistical evaluation of groundwater monitoring data. Statistical analysis was performed
to determine whether or not a statistically significant increase (SSI) above statistically
computed Upper Limits calculated from the upgradient background data set had occurred.
For this sampling event, no statistical analysis was performed on the data.
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8.0 SUMMARY

S&ME was contracted by Sorrell to provide groundwater and surface water monitoring
services at Sorrell Landfill located just off Smith Road (S.R. 1303) near Apex, North
Carolina. Groundwater samples were collected from one upgradient (background) well
(MW-1R), four shallow and one deep downgradient (compliance) wells (MW-5, MW-6,
MW-8, MW-9 and DW-1), and one off-site assessment well (GP-9). Surface water
samples were collected from the up-gradient and down-gradient surface water monitoring
points (SW-1 and SW-2).

The depth to the groundwater was measured in each monitor well and landfill methane
well located at the site. As shown on the potentiometric map (Figure 2), groundwater in
the vicinity of the landfill is projected to flow north-northwest toward an unnamed
tributary of Middle Creek. It should be noted that static water levels measured during the
April 2017 sampling event indicate that MW-8 may be located hydraulically upgradient
of the landfill cell. In addition, the groundwater elevation in DW-1 was observed to be
higher than the groundwater elevation in MW-8 during the April 2017 sampling event.
This difference in groundwater elevations indicates that an upward gradient exists
between the two water-bearing zones in the vicinity of these two wells. These findings
are consistent with historical data.

Groundwater and surface water samples were analyzed by ENCO Laboratories for
constituents listed in Appendix I. The sample from monitor well MW-8 and off-site
assessment monitor well GP-9 were also analyzed for constituents listed in Appendix II.
Laboratory analytical methods included EPA Method 6010C/6020A (metals), Method
8260B (VOCs), Method 8270D (SVOCs), Method 7470A (Mercury), and Method 9014
(cyanide).

8.1 Groundwater Results

From groundwater samples collected during the April 2017 sampling event, eight
constituents were detected at concentrations greater than their respective 2L Standards or
GWPSTs: 1,2-dichloropropane (1.5 µg/L at MW-8), benzene (10 µg/L at MW-8),
tetrachloroethene (50 µg/L at MW-8), trichloroethene (19 µg/L at MW-8), vinyl chloride
(9.3 µg/L in MW-8), cobalt (4.34 µg/L at MW-8, 11.8 µg/L at MW-9), vanadium (5.79
µg/L at MW-6), and thallium (0.498 µg/L at MW-8, 0.342 µg/L at GP-9, and 0.327 µg/L
at DW-1).

The detected analytes from the April 2017 sampling event are summarized on Table 5.

It is important to note that the laboratory method detection limit (MDL) for vinyl chloride
is 0.32 µg/L which is greater than the 2L Standard of 0.03 µg/L. Therefore, vinyl
chloride may have been present at concentrations above the 2L Standard but reported
below the MDL.
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8.2 Surface Water Samples

The inorganic constituents arsenic, barium, beryllium, chromium, cobalt, copper, lead,
nickel, vanadium and zinc, were detected above their MDLs in the sample from the
upstream (SW-1) surface water monitoring location during the April 2017 monitoring
event. Cobalt, copper, lead, vanadium, and zinc were detected in the downstream (SW-2)
surface water sample location in April 2017. All inorganic constituents detected in
samples from SW-1 and SW-2 were reported with a “J” laboratory qualifier indicating
that the values are estimated concentrations below the lowest calibration point. Organic
constituents in surface water samples collected during the April 2017 sampling event
were detected at concentrations below their respective 2B Standards. Detected
constituent concentrations in the downstream sample were similar to, or less than,
concentrations in the upstream sample.

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9.0 RECOMMENDATIONS

As required by North Carolina Solid Waste Management Rule .1634, these results should
be forwarded to the owner/operator of Sorrell Landfill for inclusion in the operating
record and to the NCDEQ Division of Waste Management for their review. In addition
to the conclusions presented in previous chapters of this report, S&ME provides the
following recommendations:

 Analytical data since 1999 have demonstrated that the use of low-flow sampling
techniques has successfully reduced reported inorganics in the samples to more
accurate results. Accordingly, it is recommended that monitoring for inorganics
continue to be limited to Appendix I inorganic compounds at the facility’s
monitor wells (no cyanide or sulfide).

 VOCs have been detected in samples collected from well MW-8 since the well
was installed in 2001. The consistent detection of VOCs at MW-8 indicates that a
source, or sources, of VOCs may be present at, or near, this well. Additional
assessment of surrounding properties was conducted in October 2008 to further
evaluate the extent of the groundwater plume in the area of MW-8. VOCs were
detected above the 2L Standards in the off-site groundwater assessment monitor
wells in October 2008 and subsequent monitoring events. To monitor the off-site
groundwater contamination, off-site assessment monitor well GP-9 was sampled
during the April 2017 sampling event. None of the VOCs detected in nearby
compliance well MW-8 were detected in off-site assessment monitor well GP-9
during the April 2017 sampling event. An assessment of corrective measures and
corrective action should be performed to address the groundwater contamination
in the area of MW-8. In the meantime, it is recommended that groundwater
monitoring at MW-8 continue to be analyzed for Appendix II VOCs and sampling
of the off-site assessment wells in the vicinity of MW-8 (GP-8, GP-9 and /or GP-
10) continue to be included as part of the regular compliance monitoring, to
monitor the extent, movement and concentration of off-site groundwater
contamination.

 Surface water quality is monitored upstream and downstream in the vicinity of the
landfill at sampling locations SW-1 and SW-2, respectively. Laboratory analysis
of surface water quality do not indicate any impact from the landfill to surface
water. Samples from surface water sampling locations SW-1 and SW-2 should
continue to be monitored for the Appendix I organic and inorganic compounds
required for detection monitoring.

 It is our understanding that the Wake County Department of Environmental
Services, Water Quality Division regularly samples the potable wells on the
adjacent properties to the south of the landfill (Dye and Herndon properties) as a
precautionary measure to protect the users of these potable wells. S&ME
recommends the results of this sampling event be provided to Wake County for
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20
consideration in deciding protective measures for the potable wells and their
users.

TABLES

TOC Elevation
(Feet MSL)
Screened Interval
(feet below TOC)
Depth to Groundwater
(Feet below TOC)
Groundwater Elevation
(Feet MSL)
MW-1R 482.92 25-45 30.11 452.81
MW-4 445.30 12-22 3.73 441.57
MW-5 393.63 7-17 4.09 389.54
MW-6 407.15 7-17 2.84 404.31
MW-7 423.42 13-28 13.40 410.02
MW-8 463.33 21.9-31.9 22.71 440.62
MW-9 425.82 14-34 16.55 409.27
DW-1 463.18 96-101 19.64 443.54
GP-7 471.32 25-35 19.64 451.68
GP-7D 471.33 55-65 19.78 451.55
GP-8 460.39 23-33 21.09 439.30
GP-9 462.19 20.1-30.1 21.03 441.16
GP-10 456.15 15-25 16.35 439.80
GP-10D 456.20 78-88 16.52 439.68
GP-11 461.77 23-33 19.60 442.17
GP-12 466.71 23-33 24.03 442.68
GP-12D 466.72 58-68 24.30 442.42
GP-13 453.70 20-30 13.81 439.89
GP-13D 453.56 59-69 14.43 439.13
GP-14 463.45 25-35 23.52 439.93
GP-15 454.32 18-28 14.92 439.40
GP-16 449.99 18-28 10.15 439.84
MMW-2 471.71 5-20 DRY DRY
MMW-3 452.50 3-18 14.48 438.02
MMW-4 445.60 3-13 9.11 436.49
MMW-5 437.81 3.5-13.5 DRY DRY
MMW-6 419.04 5-15 DRY DRY
Notes:
1. TOC = Top of Casing
2. MSL = Mean Sea Level
NM = Not Measured
TOC Elevations measured by Bateman Civil Survey, June, 2007.
GP-7 - GP-16 installed by S&ME between September 5 & 11, 2008, casing elevations by Bateman Civil Survey, September 11, 2008.
Monitoring wells MW-4, MW-5, andMW-6 installed by Law Engineering in October 1991. All other wells were installed by S&ME.
MW-9 installed by S&ME on September 18, 2007, casing elevation by Bateman Civil Survey, October 5, 2007.
Off-site Groundwater
Monitoring Wells
Well Number
Background Wells
Compliance Wells
Methane Monitoring
Wells
Permanent Methane Monitoring Wells
Permanent Groundwater Monitoring Wells
Temporary Groundwater Monitoring Piezometers
Table 1
Static Groundwater Elevations
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Sorrell Landfill, Apex, North Carolina
S&ME Project No. 1054-07-251
T:\Projects\2007\ENV\07-251 Sorrell Landfill\Reports\2017 April GW Sampling\Deliverables\Sorrell Landfill April 2017 Tables.xlsx
cm/sec ft/sec ft/day ft/year
MW-1R 25 - 45'--------
MW-4 12 - 22'--------
MW-5 7.0 - 17'--------
MW-6 7.0 - 17'1.86E-04 6.07E-06 0.525 191.47
MW-7 13 - 28'3.25E-04 1.06E-05 0.917 334.59
MW-8 22 - 32'4.00E-04 1.31E-05 1.130 412.49
MW-9 14 - 34'3.86E-04 1.26E-05 1.090 397.85
DW-1 96 - 101'3.28E-04 1.07E-05 0.924 337.44
Notes:
1. ft-bgs = feet below ground surface
3. ft/sec = feet per second
4. ft/yr = feet per year
5. -- = no site specific hydraulic conductivity values available
6. Hydraulic conductivity for MW-6 and MW-7 obtained from slug tests by S&ME, April 1999.
7. Hydraulic conductivity for MW-8, MW-9 and DW-1 obtained from slug tests by S&ME, January/March 2008.
Screened Interval
(ft-bgs)
8. Hydraulic conductivity for DW-1 was calculated from transmissivity value using the Cooper-Bredehoeft-Papadopulos solution where K=T/b.
Well Number
Background
Wells
Compliance
Wells
Hydraulic Conductivity (K)
Table 2
Summary of Hydraulic Conductivity Values
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Sorrell Landfill, Apex, North Carolina
S&ME Project No. 1054-07-251
T:\Projects\2007\ENV\07-251 Sorrell Landfill\Reports\2017 April GW Sampling\Deliverables\Sorrell Landfill April 2017 Tables.xlsx
Gradient Calculation
Segment
Monitoring
Wells
Flow
Direction
Gradient Segment
Length (feet)
Gradient
Segment
Elevations
(feet)
Horizontal
Gradient
(i, feet)
Effective
Porosity
(ne)
Hydraulic
Conductivity
(K, cm/sec)
MW-1R to 452.81
MW-9 409.27
Intermediate
Well MW-4 441.57
MW-8 to 440.62
MW-5 389.54
Intermediate
Well MW-6 404.31
0.028 Avg. Velocity =35.12 feet/year
Notes:
Horizontal velocities based on the modified Darcy equation Vgw = Ki/ne.
1. Porosity (ne) estimated for residual soils in Carolina Slate Belt
2. Average K value used for background wells and compliance wells
3. Hydraulic Gradient (i) calculated by measuring linear feet between selected contour intervals
4. Ave. Linear Velocity (v) = (1.035E06)K*i/n for units shown
5. To convert cm/sec to ft/yr, multiply n by 1.035E06
Average Hydraulic Gradient=
1.86E-04
Table 3
Groundwater Velocity Calculations
Semi-Annual Assessment Monitoring - April 12, 2017
Sorrell Landfill, Apex, NC
0.2
i 1
i 2
0.2
S&ME project Number 1054-07-251
3.25E-04
WNW 0.0297
0.02591690
1695
NNW 43.36
28.45
Velocity
(Vgw, feet/year)
T:\Projects\2007\ENV\07-251 Sorrell Landfill\Reports\2017 April GW Sampling\Deliverables\Sorrell Landfill April 2017 Tables.xlsx
pH1 Conductivity (mS/cm)2 Temperature (oC)3 Turbidity (NTUs)6
BackgroundWellsMW-1R 3.76 0.024 16.75 31.1
MW-5 5.63 0.085 16.87 2.3
MW-6 5.82 0.054 15.64 13.2
MW-8 4.04 0.065 19.46 1.1
MW-9 4.21 0.034 18.29 1.5
DW-1 4.10 0.057 18.37 0.4
Off-SiteAssessmentWellsGP-9 3.86 0.029 18.77 1.7
SW-1 4.03 0.040 17.70 47.3
SW-2 5.85 0.140 17.81 10.4
Notes:
1. pH reported in standard units
2. mS/cm = miliSiemens per centimeter
3. °C = degrees Celsius
4. mg/L = milligrams per liter
5. mV = millivolts
6. NTUs = nephelometric turbidity unitsSurfaceWaterComplianceWells Table 4
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Sorrell Landfill, Apex, North Carolina
S&ME Project No. 1054-07-251
Summary of Field Parameters
Field Parameter
Well Number
T:\Projects\2007\ENV\07-251 Sorrell Landfill\Reports\2017 April GW Sampling\Deliverables\Sorrell Landfill April 2017 Tables.xlsx
MW-1R MW-5 MW-6 MW-8 MW-9 DW-1 GP-9 Equip. Blank Duplicate SW-1 SW-2
4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017
1,1-dichloroethane 5 6 <0.13 0.53 J <0.13 3.9 <0.13 <0.13 <0.13 <0.13 <0.13 6 <0.13 <0.13
1,1-dichloroethene 5 350 <0.21 <0.21 <0.21 0.63 J <0.21 <0.21 <0.21 <0.21 <0.21 330 <0.21 <0.21
1,2-dichloropropane 1 0.6 <0.10 <0.10 <0.10 1.5 <0.10 <0.10 <0.10 <0.10 <0.10 0.5 <0.10 <0.10
1,4-dichlorobenzene 1 6 <0.19 <0.19 <0.19 1.5 <0.19 <0.19 <0.19 <0.19 <0.19 63 <0.19 <0.19
Benzene 1 1 <0.15 <0.15 <0.15 10 <0.15 <0.15 <0.15 <0.15 <0.15 1.19 <0.15 <0.15
Cis-1,2-dichloroethene 5 70.0 <0.15 <0.15 <0.15 44 <0.15 <0.15 <0.15 <0.15 <0.15 60 <0.15 <0.15
Trans-1,2-dichloroethene 5 100 <0.21 <0.21 <0.21 0.73 J <0.21 <0.21 <0.21 <0.21 <0.21 140 <0.21 <0.21
Tetrachloroethene 1 0.7 <0.17 <0.17 <0.17 50 <0.17 <0.17 <0.17 <0.17 <0.17 0.7 <0.17 <0.17
Trichloroethene 1 3 <0.15 <0.15 <0.15 19 <0.15 <0.15 <0.15 <0.15 <0.15 2.5 <0.15 <0.15
Vinyl chloride 1 0.03 <0.32 <0.32 <0.32 9.3 <0.32 <0.32 <0.32 <0.32 <0.32 0.025 <0.32 <0.32
Xylenes (total)5 500 <0.45 <0.45 <0.45 2.2 J <0.45 <0.45 <0.45 <0.45 <0.45 670 AL <0.45 <0.45
Methylene chloride 1 5 <0.23 <0.23 <0.23 5 <0.23 <0.23 <0.23 <0.23 <0.23 4.6 <0.23 <0.23
MW-1R MW-5 MW-6 MW-8 MW-9 DW-1 GP-9 Equip. Blank Duplicate SW-1 SW-2
4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017
Dichlorodifluoromethane 5 1000 NA NA NA 11 NA NA <0.20 NA NA NE NA NA
MW-1R MW-5 MW-6 MW-8 MW-9 DW-1 GP-9 Equip. Blank Duplicate SW-1 SW-2
4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017 4/12/2017
Arsenic 10 10 <6.80 <6.80 <6.80 <6.80 <6.80 <6.80 <6.80 <6.80 <6.80 150 9.92 J <6.80
Barium 100 700 13.4 34.3 30.5 84.8 32.2 11.6 12.3 <1.00 11.6 1,000 401 72.9
Beryllium 1 4*<0.130 <0.130 <0.130 <0.130 <0.130 <0.130 <0.130 <0.130 <0.130 6.5 2.01 <0.130
Chromium 10 10 <1.40 <1.40 <1.40 <1.40 <1.40 <1.40 <1.40 <1.40 <1.40 50 23.2 <1.40
Cobalt 10 1*<1.10 <1.10 <1.10 4.34 J 11.8 <1.10 <1.10 <1.10 <1.10 3 9.7 J 1.7 J
Copper 10 1000 4.88 J 2.82 J 3.37 J 2.9 J 2.99 J 2.4 J 2.59 J 7.01 J 2.85 J 2.7 AL 22.6 3.57 J
Lead 10 15 <3.10 <3.10 <3.10 <3.10 <3.10 <3.10 <3.10 <3.10 <3.10 0.54 N 59.8 <3.10
Nickel 50 100 <2.20 <2.20 <2.20 <2.20 <2.20 <2.20 <2.20 <2.20 <2.20 25 8.58 J <2.20
Vanadium 25 3.5*3.04 J 2.73 J 5.79 J <1.40 <1.40 <1.40 <1.40 <1.40 <1.40 24 119 <1.40
Zinc 10 1000 <4.40 <4.40 <4.40 11.1 12.9 <4.40 15 <4.40 <4.40 36 AL 107 <4.40
Thallium 5.5 0.28*0.231 J 0.268 J 0.198 J 0.498 J 0.342 J 0.327 J 0.202 J <0.110 0.327 J 0.24 AL <1.10 0.494 J
Notes:
1. ug/L = micrograms per liter (parts per billion).
2. SWSL = North Carolina Department of Environmental Quality Solid Waste Section Limit established in 2007.
3. 15A NCAC 2L = North Carolina Groundwater Quality Standards (Updated January 2010).9. Bold and shaded indicates above 15A NCAC 2L or GWPST.
4. GWPST = Solid Waste Section Groundwater Protection Standard.10. Duplicate = Duplicate sample taken at DW-1 for the April 2017 sampling event.
5. 15A NCAC 2B = North Carolina Surface Water Quality Standards.11. Target analytes not shown were not detected above the laboratory method detection limits.
6. NA = Not Analyzed.12. MW-9 replaced MW-7 as a shallow groundwater monitoring compliance well. MW-9 was installed by S&ME personnel on 9-18-2007.
7. J = Detected, but below the Reporting Limit, therefore, result is an estimated concentration.13. * Indicates there is currently no 2L Standard. The target analyte was compared to the Solid Waste Section Groundwater Protection Standard (GWPST).
8. B= The analyte was detected in the associated method blank.14. AL = Aquatic Life Standard; N = Narrative Standard
upstream
Surface Water SampleSample Type Quality Control SamplesBackground
Well
Table 5
Detected Analytes
S&ME Project No. 1054-07-251
15 NCAC
2B
NCDEQ
SWSL
15A NCAC
2L
Sampling Date
Sampling Location
Compliance Wells
Off-site
Assessment
Well
Sorrell Landfill, Apex, North Carolina
Semi-Annual Assessment Monitoring - April 12, 2017
downstream
EPA Appendix I Inorganic
Compounds Method 6010B/6020
(µg/L)
NCDEQ
SWSL
15A NCAC
2L
EPA Appendix II Volatile Organic
Compounds (µg/L)
NCDEQ
SWSL
15A NCAC
2L
EPA Appendix I Volatile Organic
Compounds (µg/L)
T:\Projects\2007\ENV\07-251 Sorrell Landfill\Reports\2017 April GW Sampling\Tables\Sorrell Landfill April 2017 Tables.xlsx

FIGURES

SITE
TOWN OF APEX
SCALE:
PROJECT NO:
FIGURE NO.
WWW.SMEINC.COM
DATE:
DRAWN BY:
3201 SPRING FOREST RD, RALEIGH, NC 27616
NC ENGINEER LICENSE #F-0176
SORRELL LANDFILL
APEX, NORTH CAROLINA
1" = 2000'
BTR/RDM
MAY 2017
1054-07-251
1VICINITY MAP
TOPO SOURCE: APEX, NC QUADRANGLE,
7.5-MINUTE SERIES US TOPO (2016).
MMW-6
MMW-5
MW-7
MW-1R
MW-4
OLD MW
MMW-3
SW-2
MW-6
MW-5
MW-9
EASEMENTSEDIMENT
POND
APPROXIMATE
LIMITS OF CAP
APPROXIMATE
LIMITS OF FILL
MMW-4
MW-8
DW-1
MMW-2
SW-1
GP-7
GP-7D
GP-8
GP-9
GP-11
GP-12
GP-12D
GP-14
480
460
440
420
420
440
480
460
400
500
450
450460460
47
0 490480470460450
440
3
9
0
400
410
420
430
440
450460 470480490
430
420
410
400
410
GP-10D GP-10
GP-15
GP-13D
GP-13
GP-16
P
P
5100 HERNDON LANE
5101 HERNDON LANE
PP
DITCH
DITCH
DITCH
ROCK CHECK DAM
& VELOCITY DISSIPATOR
PIPE
(452.81)
(441.57)
(410.02)
(409.27)
(404.31)
(389.54)
(441.16)
(442.17)
(443.54)
(440.62)
(438.02)
(451.68)
(451.55)
(439.30)
(439.80)(439.68)
(442.68)
(442.42)
(439.89)
(439.13)
(439.93)
(DRY)
(DRY)
(436.49)(DRY)(439.40)
(439.84)
A
P
P
R
O
X
I
M
A
T
E
G
R
O
U
N
DW
A
T
E
R
FL
OW

D
I
R
E
C
T
I
O
N
CHECKED BY:DRAWN BY:
APPROVED BY:DESIGNED BY:
PROJECT NUMBER:
SCALE:DATE:
OF:DRAWING:BYDESCRIPTIONDATENO.WWW.SMEINC.COMDRAWING NUMBER:3201 SPRING FOREST ROAD, RALEIGH, NC 27616 NC ENG. LICENSE #F-0176 PHONE: [phone]SPWBTR/RDM
MAY 20171" = 100'
1054-07-251
2 SORRELL LANDFILLAPEX, NORTH CAROLINAGROUNDWATER POTENTIOMETRIC MAPAPRIL 2017LEGEND
MONITORING WELL
DEEP MONITORING WELL
METHANE MONITORING WELL
SURFACE WATER SAMPLE LOCATION
SITE PROPERTY BOUNDARY
APPROXIMATE LIMITS OF CAP
APPROXIMATE LIMITS OF FILL
TOPOGRAPHIC CONTOUR LINES
HYDROLOGIC FEATURE
FENCE LINE
POTABLE WELLP
APPROXIMATE LOCATION OF DITCH
GROUNDWATER CONTOUR LINES
GROUNDWATER ELEVATION
NOT MEASURED
(446.09)
(NM)
445
APPROXIMATE GROUNDWATER FLOW DIRECTION
NOTE:
1.TOPOGRAPHIC CONTOURS FROM NCDOT, DATED 2007
2.STREAM / RIVER FEATURES FROM WAKE COUNTY GIS
LAYER "HYDROLINE"
3.SITE COMPRISED OF THREE CONTIGUOUS PARCEL, WAKE
COUNTY PIN NUMBERS: 0751505892, 0751407981, 0751400697
4.BOUNDARY SURVEY WAS COMPILED BY BATEMAN CIVIL
SURVEY ON MAY 2007 AND MAY 2008
5.WELLS DW-1, GP-3, GP-7D, GP-10D, GP-12D, GP-13D, AND
METHANE MONITORING WELLS (MMW) NOT USED FOR
GROUNDWATER CONTOURING395400405
410
415
420
425
430
435
440
445
450390

APPENDIX I
LABORATORY REPORTS

APPENDIX II
HYDRAULIC GRADIENT / GROUNDWATER
FLOW VELOCITY CALCULATIONS

JOB NAME Sorrell Landfill JOB NO.
SUBJECT Hydraulic Gradient SHEET NO.
DATE
PURPOSE: COMPUTED BY
To determine the average true hydraulic gradient
CALCULATION FOR HYDRAULIC GRADIENT [ i = (h1-h2)/L ]
Given:Well GW Elevation
kA ZONE: hydraulic conductivity 0.25 to 1.13 FT/DAY MW-1R 452.81
Ŋ: porosity 0.2 dimensionless MW-9 409.27
iAVG.: AVERAGE HYDRAULIC GRADIENT 0.0270 FT/FT MW-4 441.57
MW-8 440.62
CALCULATED FROM THE AVERAGE OF THREE POINT SOLUTIONS MW-5 389.54
USING MONITOR WELLS MW-MW-1, MW-9, and MW-4 or MW-8, MW-5 and MW-6 MW-6 404.31
GRADIENT:
distance
DETERMINED FROM 3 POINT PROBLEM BY PROJECTION
i4 = MW-1R – MW-9 =452.81 -409.27 =0.0258
distance
Use Elevation of Groundwater at MW-4 to establish elevation between MW-1R and MW-9
MW-1R - MW-4 =452.81 -441.57 =436.28
gradient (MW-1R and
MW-9)
Draw line from MW-4 to point located 385.10 feet from MW-1R to MW-9.
Measure new distance between MW-1R and MW-9 perpendicular to line plotted for the contour. Recalculate Gradient
i4 = MW-1R – MW-9 =452.81 -409.27 =0.0259
New Distance
True Hydraulic Gradient =0.02592
i4 = MW-8 – MW-5 =440.62 -389.54 =0.0295
distance
Use Elevation of Groundwater at MW-6 to establish elevation between MW-8 and MW-5
MW-8 - MW-6 =440.62 -404.31 =1252.07
gradient (MW-8 and MW-5)
Draw line from MW-6 to point located 1244.83 feet from MW-8 to MW-5.
Measure new distance between MW-8 and MW-5 perpendicular to line plotted for the contour. Recalculate Gradient
i4 = MW-8 – MW-5 =440.62 -389.54 =0.029715
New Distance
True Hydraulic Gradient =0.029715
Average True Hydraulic Gradient =0.0278
0.0290
1719
1054-07-251
1 of 1
5/8/2017
BW
1690
0.0258
1680
1734
T:\Projects\2007\ENV\07-251 Sorrell Landfill\Reports\2017 April GW Sampling\Deliverables\Sorrell Landfill April 2017 Tables.xlsx

APPENDIX III
SUMMARY TABLE of
ELECTRONIC DATA DELIVERABLE (EDD)