4101_Guilford_CityHighPoint_Riverdale_MSWLF_Seaboard_PFASMonitoringWorkPlan_FID1817457_20230912

SEABOARD GROUP II AND CITY OF HIGH POINT, NC
TO: North Carolina Department of Environmental Quality
ATTN: Eric Aufderhaar, Hazardous Waste Section
Jackie Drummond, Solid Waste Section
FROM: Seaboard Group II and City of High Point
SUBJECT: Technical Memorandum No. E-12 — PFAS Monitoring Workplan
DATE: September 11, 2023
In response to the NCDEQ's August 10, 2023 request to conduct water quality monitoring for PFAS
compounds at the Site, the Seaboard Group II and the City of High Point (Parties) have prepared this
Workplan in accordance with the Remedial Action Settlement Agreement (RASA), Exhibit A - Statement
of Work, Section B. This Workplan represents Technical Memorandum No. E-12 (TM-12) developed under
the amendment provisions of the RASA.
The NC Solid Waste Section has issued two Memoranda, dated March 13 and July 17, 2023, regarding
selection of sample locations, sample collection and analytical methodology, monitoring frequency, and
data reporting. These two documents, in conjunction with the virtual meeting between the Parties and
NCDEQ on August 2, 2023, provide the basis for development of this Workplan.
The objective of this Workplan is to analyze groundwater and surface water at the former Seaboard
Chemical/Riverdale Drive Landfill Site (Site) for the presence of the 40 PFAS compounds identified by EPA
Draft Method 1633. The groundwater monitoring wells and surface water sample locations included in
this Workplan were selected to determine if PFAS compounds are present in groundwater and/or surface
water at the Site.
The focus of this Workplan is to analyze groundwater quality at select monitoring locations indicative of
Site conditions for the presence of PFAS compounds. The following criteria were used to select the
proposed water quality monitoring locations:
• An upgradient groundwater monitoring location which has not been impacted by activities at the
Site.
• Groundwater monitoring locations which are representative of the water quality hydraulically
downgradient of the Site.
• Monitoring well locations which have shown the presence of Site contaminants during water
quality monitoring events conducted over the past 25 years.
• Surface water monitoring locations near the downgradient property boundary.
Page - 1 of 4

SEABOARD GROUP II AND CITY OF HIGH POINT, NC
In line with these selection criteria, the following water quality monitoring locations are proposed for
evaluation of PFAS compounds by EPA Draft Method 1633:
Upgradient Groundwater Monitoring
The existing upgradient groundwater monitoring well MW-1, screened from 47'-57', will provide an
upgradient water quality location which has not been affected by activities at the Site. The historical
water quality data for this well is provided on Table 1.
Northern Intermittent Stream (NIS) Area
The NIS area consists of the older portion of the former Landfill and any discharges from the former Burn
Pit area. This area of the closed Landfill is currently used for Zones 1 — 11 of the phytoremediation
treatment system. One groundwater monitoring well and one surface water location are proposed to
analyze for the presence/absence of PFAS compounds:
• Monitoring well MW-12A, screened from 5' — 20', is proposed to analyze shallow groundwater
immediately downgradient of the closed Landfill area and phytoremediation zones 1- 11. This is
the shallow well in a three well nest and has historically shown the highest contaminant
concentrations at this location (Table 1).
• Surface water monitoring station SW-2 is proposed to analyze overland flow from
Phytoremediation Zones 1 - 11 and topographically upgradient properties.
Southern Intermittent Stream (SIS) Area
The SIS drainage area has been identified as the primary contaminant migration pathway. The presence
of the landfill, Soil Residue Mound, and the operational areas of the former Seaboard Chemical facility
serve as source areas for the contaminants observed in the SIS drainage valley. Portions of
phytoremediation zones 2, 3, 4, 15, and 16 also drain to the SIS valley. The majority of the groundwater
extraction activities occur in the SIS drainage valley as noted on Figure 1. Two groundwater monitoring
wells and one surface water location are proposed to analyze for the presence/absence of PFAS
compounds:
• Monitoring well MW-3C (screened from 47' — 57') is proposed to analyze the shallow bedrock
zone at the downgradient extent of the SIS drainage valley. The historical contaminant
concentrations in MW-3C well pair has decreased over the past five years due to the operation of
the extraction system at PW-DR1.
• Monitoring well PW-61 (screened from 90' — 100') is proposed to analyze groundwater from the
SIS drainage valley. This well represents the approximate eastern extent of the SIS drainage valley
contaminant plume. The historical contaminant concentration in this well has remained stable
over the past five years.
• Surface water monitoring station SW-4 is proposed to analyze the shallow groundwater discharge
in the SIS drainage valley which outlets into the SIS Basin.
Page - 2 of 4

SEABOARD GROUP II AND CITY OF HIGH POINT, NC
Eastern Boundary of Former Landfill Area
The eastern extent of the former Landfill adjacent to Interstate 85 is downgradient of Zones 12 — 16 of
the phytoremediation treatment system. The monitoring wells on the eastern border of the former
Landfill are located along a drainage depression that likely represents a preferential groundwater flow
path. To analyze for the presence/absence of PFAS compounds in this area, the sampling of one
groundwater monitoring well is proposed:
Groundwater Monitoring well MW-10, screened from 8' — 28', will analyze water quality in the
shallow groundwater aquifer near the outlet of a wet -weather drainage feature. The contaminant
concentrations in this well have been minor in this well over the past five years.
Groundwater and Surface Water Collection and
The groundwater and surface water evaluation for PFAS compounds will occur as a standalone monitoring
event to reduce the potential for cross -contamination during sample collection. The samples will be
collected using low -flow techniques to reduce turbidity in the samples. PFAS-specific sample collection
precautions will be followed and the sample team will adhere to guidance provided by the Interstate
Technology and Regulatory Council (https://pfas-1.itrcweb.org). The following general modifications to
the low -flow sampling procedure are planned to limit the potential for cross -contamination during
collection of the PFAS samples:
• The tubing used for sample collection will consist of silicone tubing for the peristaltic pump head
and HDPE for the downhole tubing. New tubing will be used for each sample location.
• Powder -free nitrile gloves will be worn by all sampling personnel which will be changed out
between each sample location.
• The sample collection team will consist of two technicians; one person will operate the pump and
tubing while the second person will only handle the sample containers.
• No Teflon TM products, insect repellant, or sunscreen will be used by the sample collection team
during the monitoring event.
A trip blank, two equipment blanks (one following initial sample collection and the second following final
sample collection) and one duplicate sample will be collected as part of this effort.
The surface water samples for PFAS analysis (SW-2 and SW-4) will be collected as grab samples directly in
the laboratory -supplied containers. Sampling personnel will wear new disposable powder -free nitrile
gloves for each sample location.
All collected samples will be sent to a laboratory accredited to perform draft Method 1633 on aqueous
solutions.
Page - 3 of 4

SEABOARD GROUP II AND CITY OF HIGH POINT, NC
The results of the sampling contained in this Work Plan will be tabulated and provided to NCDEQ as
discussed during the August 2, 2023 virtual meeting regarding this effort.
Please contact Craig Coslett (610/435-1151, Extension 8001) or Gary Babb (919/605-4719) if there are any
questions or comments regarding this Technical Memorandum.
Respectfully,
Seaboard Group II and City of High Point
A
Mr. Craig Coslett, Project Coordinator
de maximis, inc.
1550 Pond Road, Suite 120
Allentown, PA 18104
[e-mail]
Gary D. Babb, P.G.
Babb & Associates, P.A.
[e-mail]
Attachments
Figure 1— Proposed PFAS Sample Locations
Table 1— Historical VOC Analytical Summary
2' SEAL 1' _
488
Page - 4 of 4

Landfill Property Line
N %
-1 ad
West Lobe
Phyto Zones
1 thru 11
SW-6
Located Upstream
�At Kivett Dr. Bridge
■NIS Sump
MW-12A
%' MW-12B
MW-1 CPW-14D
D
SW-DRP2
Soil
Residue _ low
PW-131 MW-3C ",OW-DR2
LS-1
VIV
PW-51D ° •PW-D
ORW-SIS8
Mechanical Treatment 1 SIS7
System and LS-2 LCHT5� SW-4
�i P pe L •
MW-15A gas
S -3
W-4 :.
Facility♦ �� ORW IS2
SW-5
• RW-SIS4* •-SIS3 ®r ;k
PW-SF10 W-3D PW-41
R-1
,h PW-16D
..
PW-15D
:ll
.
.ItPW-6D
PW-61
LCHT2
■
RW-LFS2
Ah
OW-LFS2"
'AG East Lobe
Pond 3 Phyto Zones
ry� z Former 12 thru 16
kq Site
F
Seaboard Property Line
R
N
Landfill Property Li
:D
MW-6
PW-101„rI,MW-10
RW-LFS1 �' PW-101
LCHT1 -
Groundwater Monitoring Well
Surface Water Monitoring Locatio
Leachate Collection Tank/Sump
Shallow Groundwater Recovery Well
Deep Groundwater Recovery Well
Proposed PFAS Sample Location
vvell ID Screen Interval
I
MW-1 47' — 57'
MW-12A 5' — 20'
MW-3C 47' — 57'
PW-61 90' — 100
MW-10 8' — 28'
SW-DRP11
Located Downstream
At The Confluence O
Richland Creek
01

TABLE 1
GROUND WATER ANALYTICAL RESULTS - VOCs and 1,4-Dioxane
SEABOARD CHEMICAL/RIVERDALE DRIVE LANDFILL SITE
Page I of 3
VOLATILE ORGANIC COMPOUNDS (ug/L)
1
C
�
y
y
Sample
O
n
N
N
0
p
N
O
M
N
Sample I.D.
b
q
b
F
0
0
b
Date
0
0
0
0
c,
Q-
S
3
S
3
3
M
O
3
O
S
S
S
S
3
3
O
?
O
O
O
O
O
A
y
0
O
S
0
O
`G
fD
O
O
O
7
S
O
O
O
O
O
0
D
W
0
a
O
O
O
a
n
O
-4
O
O
n
O
N
O
_O
N
..
fD
..
M
W
..
O
0
O
O
n
M
O
3
O
7
(D
O
.O.
M
W
7
3
M
.•
O
M
M
S
:
<
O
x
3
S
S
3
=r
3
-a
�(
.r
N
N
O
N
3
�+
O
S
S
N
O
3
C
S
3
O
O
O
0)
3
0)
7
N
7
fD
7
0)
7
0)
3
a)
7
O
7
fD
7
M
N
7
0)
7
0)
7
fD
7
fD
7
M
lD
7
fD
7
N
7
lD
7
CL
>v
0
(D
fD
I M
M
N
M
M
M
M
M
M
M
M
M
M
CD
M
M
N
M
M
U)
NC 2L Standard
NE
200
0.6
6
350
0.4
0.6
3
6000
1
0.3
50
3,000
70
3
70
600
5
0.7
600
100
3
0.03
500
MW-1
1/28/1997
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
3/5/2009
17
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
15.3
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
2.1
<1.0
<1.0
<1.0
<1.0
<1.0
<2.0
ND
3/31/2010
0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<2.0
<5.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
ND
ND
11/2/2011
0
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<3.0
<5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
ND
11/20/2012
54
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
54.4
<5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
ND
1/21/2013
ND
<2.0
12/9/2013
ND
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<2.0
<5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<1
ND
12/8/2014
ND
<1
<1
<1
<1
<1
<1
<2
<5
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
ND
10/26/2015
ND
<1
<1
<1
<1
<1
<1
<2
<5
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
ND
11/14/2016
ND
<1
<1
<1
<1
<1
<1
<2
<20
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
ND
10/11/2017
ND
<1
<1
<1
<1
<1
<1
<2
<20
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
ND
11/1/2018
ND
<1
<1
<1
<1
<1
<1
<2
<20
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
<5
9/10/2019
ND
<1
<1
<1
<1
<1
<1
<2
<20
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
ND
10/13/2020
ND
<1
<1
<1
<1
<1
<1
<2
<20
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<2
ND
10/26/2021
ND
<1
<1
<1
<1
<1
<1
<2
<20
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<2
ND
10/12/2022
ND
<1
<1
<1
<1
<1
<1
<2
<20
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<0.3
ND
MW-3C
8/6/1996
273
11
ND
150
31
5.0
ND
ND
6
37
ND
ND
ND
ND
2 J
4J
ND
ND
14
13
ND
ND
1/28/1997
197
6
ND
92
21
3.0
ND
ND
ND
ND
41
14
ND
NA
ND
1 J
ND
ND
ND
9
10.0
ND
ND
9/26/2000
138
<5
<5
41
7.2
<5
<5
<100
NA
<5
32
<10
<5
21
<5
<5
<5
37
<5
<5
<10
<10
ND
9/5/2001
178
<5
<5
22.6
<5
<5
<5
117
<10
<5
24.2
<10
<5
14.6
<5
<5
<5
<5
<5
<5
<10
<5
ND
9/18/2002
152
<5
<5
18.4
<5
<5
<5
94.6
<10
<5
27.3
<10
<5
12
<5
<5
<5
<5
<5
<5
<10
<5
ND
9/19/2003
103
<5
<5
<5
<5
<5
<5
90
<10
<5
13.4
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<5
ND
8/17/2004
132
<5
<5
19.4
<5
<5
<5
71
<10
<5
30.0
<10
<5
12.4
<5
<5
<5
<5
<5
<5
<10
<5
ND
2/27/2009
589
<1.0
<1.0
104
20.3
4.4
<1.0
160
<5.0
3.0
<1.0
151
32.7
<1.0
<1.0
70.1
<1.0
<1.0
1.9
<1.0
<1.0
2.5
39.4
<2.0
ND
3/30/2010
863
<1.0
<1.0
161
32.4
6.31
<1.0
186
<5.0
3.92
<1.0
249
45.7
<1.0
<1.0
108
<1.0
4.87
1.71
<1.0
<1.0
2.71
61
ND
ND
11/1/2011
1,861
29.1
<0.5
396
144
14
<0.5
80
<0.5
9.94
<0.5
459
192
<0.5
<0.5
364
<0.5
<0.5
3.09
<0.5
1.15
8.74
157
<0.5
3.26
11 /20/2012
1,798
28.5
<0.5
361
106
<0.5
<0.5
268
<0.5
8.73
<0.5
386
150
<0.5
<0.5
314
<0.5
4.30
3.83
1.26
1.40
8.36
146
0.7
10.31
12/11/2013
2,268
18.6
<5
383
107
15
<5
549
<50
9
<5
559
137
<5
<5
318
<5
<5
<5
<5
<5
<5
173
<5
ND
12/11/2014
2,051
100
<1
290
170
<1
<1
311
<5.0
12
17.0
330
60
<1
<1
620
<1
<1
<1
<1
<1
11
130
<3
ND
10/27/2015
1,262
66
<1
210
100
<1
<1
308
>50
10
<1
350
40
<1
<1
410
<1
<1
<1
<1
<1
9.4 J
67
<30
ND
11/14/2016
872
67
<10
94
56
<10
<10
190
<10
5.4 J
12.0
150
<10
<10
<10
270
<10
<10
<10
<10
<10
6.0
27
<30
ND
10/10/2017
402
15
<1
57
22
1.8
<1
120
<20
2.2
<1
49
6.2 J
<1
<1
100
<1
<1
0.81 J
<1
0.73 J
2.0
31
<3
1.70
11/2/2018
414
6
<1
54
30
1.9
<1
110
<20
3.2
<1
66
6.3
<1
<1
110
<1
<1
0.62 J
<1
0.61 J
2.3
22
<3
2.60
9/11/2019
288
<10
<10
41
17
<10
<10
94
<200
<10
<10
50
<10
<10
<10
72
<10
<10
<10
<10
<10
<10
14
<30
ND
10/13/2020
246
1.7
<1
38
13
1.5
<1
64
<20
1.6
<1
50
5.4
<1
<1
46
<1
<1
<1
0.57 J
0.55 J
1.4
23
<2
ND
10/26/2021
156
<1
<1
37
2
1.4
<1
67
<20
0.93 J
<1
36
2.8
<1
<1
9.8
<1
<1
<1
<1
0.53 J
<1
21
<2
ND
10/17/2022
173
<1
<1
28
5
1.3
<1
39
<20
0.97 J
<1
64
<1
<1
<1
18.0
<1
<1
<1
<1
0.56 J
<1
15
<3
1.51

TABLE 1
GROUND WATER ANALYTICAL RESULTS - VOCs and 1,4-Dioxane
SEABOARD CHEMICAL/RIVERDALE DRIVE LANDFILL SITE
Page 2 of 3
a,
1
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v;
Sample
p
^'
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c
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Date
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b
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fD
3
N
3
CD
3
Q
2)
n
fD
M
fD
CD
fD
fD
CD
M
fD
M
fD
fD
fD
fD
fD
fD
CD
M
fD
CD
fD
to
NC 2L Standard
NE
200
0.6
6
350
0.4
0.6
3
6000
1
0.3
50
3,000
70
3
70
600
5
0.7
600
100
3
0.03
500
MW-10
1/27/1997
126
ND
ND
6
ND
ND
ND
120
ND
2 J
ND
ND
ND
ND
ND
ND
ND
ND
1 J
ND
ND
ND
7/14/1998
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
9/26/2000
258
<5
<5
7.6
<5
<5
<5
250
NA
<5
<5
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<10
ND
9/6/2001
335
<5
<5
<5
<5
<5
<5
335
<10
<5
<5
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<5
ND
9/19/2002
234
<5
<5
<5
<5
<5
<5
234
<10
<5
<5
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<5
ND
9/16/2003
221
<5
<5
<5
<5
<5
<5
221
<10
<5
<5
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<5
ND
8/19/2004
198
<5
<5
<5
<5
<5
<5
198
<10
<5
<5
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<5
ND
3/6/2009
176
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
162
6.4
1.1
<1.0
4.1
<1.0
<1.0
<1.0
<1.0
<1.0
2.2
<1.0
<1.0
<1.0
<1.0
<1.0
<2.0
ND
3/29/2010
184
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
166
10.6
<1.0
<1.0
3.82
1.26
<1.0
<1.0
<1.0
<1.0
2.31
<1.0
<1.0
<1.0
<1.0
<1.0
ND
ND
11 /1 /2011
56
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
47
<0.5
<0.5
<0.5
3.99
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
6.45
11/19/2012
148
<5
74
<5
<5
<5
<5
74.4
<50
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
ND
12/10/2013
33
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
28.1
<5
<0.5
<0.5
2.27
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<1
2.7
12/10/2014
137
<1
<1
<1
<1
<1
<1
133
<5
<1
<1
2.6
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
1.2
10/26/2015
104
<1
<1
<1
<1
<1
<1
103
<5
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
1.1
11/14/2016
130
<1
<1
<1
<1
<1
<1
130
<20
0.78 J
<1
2.8 J
<1
<1
<1
0.41 J
<1
<1
<1
<1
<1
<1
<1
<3
ND
10/10/2017
150
<1
<1
<1
<1
<1
<1
150
<20
<1
<1
<1
1.8 J
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
ND
10/31/2018
160
<1
<1
<1
<1
<1
<1
160
<20
<1
<1
0.93 J
1.1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
ND
9/10/2019
74
<1
<1
<1
<1
<1
<1
72
<20
<1
<1
1.5
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
ND
10/12/2020
14
<1
<1
<1
<1
<1
<1
14
<20
<1
<1
0.46 J
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<2
ND
10/26/2021
10
<1
<1
<1
<1
<1
<1
10
<20
<1
<1
0.46 J
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<2
ND
10/14/2022
12
<1
<1
<1
<1
<1
<1
12
<20
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
ND
MW-12A
1/23/1997
11
2 J
ND
ND
3 J
ND
ND
ND
ND
2 J
ND
ND
ND
ND
ND
ND
2 J
ND
2 J
ND
ND
ND
7/10/1998
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
10/30/2000
ND
<5
<5
<5
<5
<5
<5
<100
<5
<5
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<10
ND
9/6/2001
12
<5
<5
<5
<5
<5
<5
<10
12.3
<5
<5
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<5
ND
9/20/2002
27
<5
<5
<5
<5
<5
<5
11.7
14.9
<5
<5
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<5
ND
9/16/2003
28
<5
<5
<5
<5
<5
<5
11.9
15.6
<5
<5
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<5
ND
8/18/2004
44
<5
<5
<5
<5
<5
<5
<10
43.7
<5
<5
<10
<5
<5
<5
<5
<5
<5
<5
<5
<10
<5
ND
3/6/2009
40
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<2.0
38.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
1.9
<1.0
<1.0
<1.0
<1.0
<1.0
<2.0
ND
4/1/2010
6
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
2.50
<5.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
3.09
<1.0
<1.0
<1.0
<1.0
<1.0
ND
ND
11 /2/2011
38
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
29.0
<5
<0.5
<0.5
8.04
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
<0.5
0.61
11/19/2012
203
<5
<5
<5
<5
<5
<5
203
<50
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
ND
12/10/2013
210
<5
<5
<5
<5
<5
<5
210
<50
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<5
<10
ND
12/11/2014
226
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
210
8.3
<1.0
<1.0
5.6
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<3
1.7
10/27/2015
213
<1
<1
<1
<1
<1
<1
200
<5
<1
<1
11
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
2.2
11/14/2016
207
<1
<1
<1
<1
<1
<1
200
19 J
<1
<1
5.9
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
1.5
10/10/2017
273
<1
<1
<1
<1
<1
<1
260
<20
<1
<1
11
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
1.7
11/1/2018
93
<1
<1
<1
<1
<1
<1
79
<20
<1
<1
11
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
2.9
9/10/2019
189
<1
<1
<1
<1
<1
<1
180
16 J
<1
<1
6.2
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<3
2.9
10/13/2020
34
<1
<1
<1
<1
<1
<1
31
<20
<1
<1
1.0
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<2
2.0
10/26/2021
188
<1
<1
<1
<1
<1
<1
180
<20
<1
<1
5.8
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<1
<2
1.7
10/17/2022
1 157
<1
I <1
<1
<1
<1
I <1
1 150
1 <20
I <1
<1
6.9
1 <1
<1
<1
<1
<1
<1
<1
<1
<1
<1
I <1
<3
ND

TABLE 1
GROUND WATER ANALYTICAL RESULTS - VOCs and 1,4-Dioxane
SEABOARD CHEMICAL/RIVERDALE DRIVE LANDFILL SITE
Page 3 of 3
Sample I.D.
Sample
p
Date
�,
a
?
O
O
y
3
O
O
N
..
3'
D)
3
fD
^'
M
s
O
O
fD
..
3'
01
3
CD
b
s
O
O
(D
3'
N
7
M
1
q
s
O
O
3'
CD
3
CD
N
b
0
O
O
O
,.
3'
a)
3
fD
b
a
3
O
aA
'a
0
O
'O
0)
3
I M
_G
O
X
a)O
3
CD
D
0
CD
.r
3
I M
W
O
3
N
CD
3
M
0
o
3
m
,�
y
n
3'
O
CL
M
n
O
p
rr
fD
3
N
N
3
fD
n
3
O
O
M
..
=r
a)
3
I M
n
3'
O
O
�+
n
E
O
p
S
.O.
S
c)
3
fD
v;
c,
3
O
O
O
-
3'
fD
3
I N
m
S
`<
a
W
3
N
fD
3
M
3
fD
n
3'
O
M
fD
n
3
O
O
fD
�+
S
lD
3
CD
-4
O_
C
M
3
M
a,
c,
S_
O
O
fD
a
3'
N
3
N
n
3
O
O
fD
-
3'
lD
3
CD
3
n
S_
O
Q
M
3
O
N
:
O
2)
O
3'
CD
C
O
n
to
NC 2L Standard
NE
200
0.6
6
350
0.4
0.6
3
6000
1
0.3
50
3,000
70
3
70
600
5
0.7
600
100
3
0.03
500
PW-61
1/28/1997
33
ND
ND
11
ND
1 J
ND
ND
ND
ND
14
4 J
ND
ND
1 J
ND
ND
ND
2 J
ND
ND
ND
7/14/1998
46
ND
ND
10
ND
ND
ND
ND
ND
ND
14
4 J
ND
5
ND
ND
5
ND
ND
3 J
ND
ND
5
9/26/2000
29
<5
<5
12
<5
<5
<5
<100
<5
8.4
<10
<5
8.3
<5
<5
<5
<5
<5
<5
<10
<10
ND
9/12/2001
28
<5
<5
10.7
<5
<5
<5
<10
<10
<5
7.2
<10
<5
9.9
<5
<5
<5
<5
<5
<5
<10
<5
ND
9/19/2002
31
<5
<5
12.2
<5
<5
<5
<10
<10
<5
9.0
<10
<5
9.8
<5
<5
<5
<5
<5
<5
<10
<5
ND
10/20/2003
47
<5
<5
12.1
<5
<5
<5
11.6
<10
<5
9.9
<10
<5
13
<5
<5
<5
<5
<5
<5
<10
<5
ND
8/25/2004
42
<5
<5
10.6
<5
<5
<5
11.7
<10
<5
6.2
<10
<5
13.0
<5
<5
<5
<5
<5
<5
<10
<5
ND
3/4/2009
8.2
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
<2.0
<5.0
<1.0
<1.0
<1.0
<1.0
<1.0
<1.0
2.0
<1.0
2.4
<1.0
3.8
<1.0
<1.0
<1.0
<2.0
ND
3/31/2010
143.1
<1.0
<1.0
32
1.63
3.47
<1.0
22.5
<5.0
<1.0
<1.0
35.7
10.3
<1.0
<1.0
25.2
<1.0
<1.0
1.56
<1.0
<1.0
2.81
7.88
ND
ND
11/3/2011
damaged
11/21/2012
damaged
12/10/2013
damaged
new well
12/10/2014
115
0.41 J
<1
26
2.2
<1
<1
47.9
<5
<1
<1
2.2
<1
<1
<1
24
<1
1.1
0.7 J
0.7 J
<1
1.1
3.3
4.8
1.9
10/27/2015
98
<1
<1
20
1.1 J
3
<1
46.7
<5
<1
<1
7.6
<1
<1
<1
18
<1
<1
0.74 J
<1
<1
1.4
<1
<3
1.1
11/17/2016
132
<1
<1
19
1.1 J
11
<1
56
<20
0.47 J
<1
21
<1
<1
<1
18
<1
0.53 J
1.0
<1
<1
2.5
3.6
<3
3.89 J
10/10/2017
148
<1
<1
25
0.92 J
3.6
<1
71
<20
0.52 J
<1
19
<1
<1
<1
25
<1
<1
0.42 J
<1
<1
1.1
3.0
<3
1.4
11/1/2018
128
<1
<1
17
1.1
3.2
0.4 J
60
<20
0.58 J
<1
14
<1
<1
<1
24
<1
<1
0.8 J
<1
<1
1.7
4.7
<3
1.8
9/12/2019
148
<1
<1
19
1.0
2.9
<1
79
<20
0.74 J
<1
13
<1
<1
<1
26
<1
<1
0.42 J
<1
<1
<1
5.3
<3
1.8
10/13/2020
137
<1
<1
20
1.4
3.3
<1
63
<20
0.74 J
<1
15
<1
<1
<1
26
<1
<1
0.52 J
<1
0.43 J
1.6
4.5
<2
1.8
10/28/2021
115
<1
<1
11
0.74 J
2.1
<1
69
<20
0.62 J
<1
9.6
<1
<1
<1
18
<1
<1
0.50 J
<1
<1
<1
3.2
<2
2.0
10/14/2022
116
<1
<1
8.3
<1
2.0
<1
86
<20
<1
<1
5.2
<1
<1
<1
12
<1
<1
<1
<1
<1
<1
1.6
<3
1.2
ug/1= micrograms per liter J = Estimated Value ND = Not Detected NA - Not Analyzed Bold type indicates value exceeds NC 2L ground water standard