WS-5671_20030_CA_O_20220323_SWSampling

Arcadis G&M of North
Carolina, Inc.
Wade I
5420 Wade Park
Boulevard
Suite 350
Raleigh
North Carolina 27607
Phone: [phone]
Fax: [phone]
www.arcadis.com
NC Engineering License # C-1869
NC Surveying License # C-1869
1/3
Gene Mao, Hydrogeologist
Environmental Health Division
Guilford County Dept. of Health and Human Services
400 W. Market Street
Suite 300
Greensboro, NC 27401
Date: March 23, 2022
Our Ref: 30067215
Subject: FISERV (Former ExxonMobil Facility 99GRE)
101 N. Spring Street
Greensboro, Guilford County, North Carolina
Incident No. 20030
Dear Mr. Mao,
On behalf of ExxonMobil Environmental and Property Solutions Company (E&PS), this letter provides responses
to comments received from Guilford County (June 7, 2021, Attachment 1) with further correspondence on June
10, 2021, pertaining to FISERV (Former ExxonMobil Facility 99GRE; Site) located in Greensboro, Guilford
County, North Carolina (Figure 1 and Figure 2).
Fourth Quarter Groundwater Monitoring and Sampling Report – 2020
Comments are provided in italics typeface followed by the response in standard typeface.
Comment #1: No surface water samples have been collected from the creek located downgradient from the site.
A sample needs to be collected from the creek for lab analysis to test the modeling result.
Response #1: As outlined in the Comprehensive Site Assessment Report (Arcadis, October 2012) (CSA), an
unnamed tributary to North Buffalo Creek was identified approximately 440 feet west (downgradient) of the Site
source and approximately 160 feet west of the Site boundary. On June 23, 2021, Arcadis completed a Site
reconnaissance confirming the presence of an unnamed tributary at the approximate distances listed in the
October 2012 CSA.
However, based on the groundwater modeling report submitted to the NCDENR on March 7, 2012 (Arcadis,
March 2012), the results for the groundwater monitoring modeling indicated that dissolved-phase concentrations
of constituents of concern (COCs) did not extend beyond the downgradient edge of the Site property. In order to
make that determination, hydraulic testing and modeling were conducted to address dissolved-phase
concentrations of COCs, namely benzene, toluene, ethylbenzene, and total xylenes (BTEX), as well as 1,3,5-
trimethylbenzene (135TMB) and ethylene dibromide (EDB), specifically in monitoring wells MW-1R and MW-4.
The approach utilized a set of analytical equations to conservatively estimate groundwater flow velocity and
contaminant migration rates and distances while accounting for the sorption and degradation of each COC along
an assumed plume centerline flow path. The calculations used were consistent with the United States
Environmental Protection Agency (US EPA) approach using models such as BIOSCREEN or BIOCHLOR natural
Mr. Gene Mao
Guilford County, North Carolina
March 23, 2022
www.arcadis.com
EM 99GRE RTC Letter G. County 220321
2/3
attenuation models. However, the modeling Arcadis utilized was more conservative and realistic due to the
equations not assuming an infinite amount of vertical mixing or dispersion inherent in those two-dimensional
models.
During the June 23, 2021, site visit, it was observed that a portion of the unnamed tributary downgradient from the
Site appears to be lined with impervious material on the sides to support overhead structures (i.e. buildings,
parking lot(s), roadway(s)). This impervious material would prevent any potential impacts from the upgradient Site
to enter the unnamed tributary.
Additionally, the most recent concentrations outlined in the Fourth Quarter Groundwater Monitoring and Sampling
Report – 2020 (Arcadis, February 2021), indicate concentrations have significantly decreased in monitoring well
MW-1R and generally remained stable in monitoring well MW-4 further indicating that modeling results are valid, if
not better, with the decreasing concentrations. The most downgradient sentinel monitoring wells, MW-6 and MW-
7, continue to remain with COCs at non-detect. Groundwater analytical concentrations are outlined the attached
Table 1.
Drinking water is supplied by the City of Greensboro utilizing three surface water sources; Lake Higgins, Lake
Brandt, and Lake Townsend (2020 Annual Drinking Water Quality-Consumer Confidence Report, Greensboro
North Carolina). These lakes are in northern Guilford County in the upper Cape Fear River Basin within a
protected watershed, over approximately 30,000 to 40,000 feet (5.7 to 7.6 miles) away from the Site. Based on
observations noted by Arcadis on June 23, 2021, the unnamed tributary flow direction is going north to south and
away from potential drinking water sources.
Comment #2: Benzene has increased in MW-9 since March 2019. MW-9 appears located side-gradient from the
source area. But MW-9 and MW-10 have not been surveyed. GW may also flow southwesterly toward MW-10,
and GW contamination may have migrated offsite from MW-9. Therefore, the elevation of these two wells need to
be surveyed for the construction of iso-potentiometric surface map.
Response #2: On June 23, 2021, Arcadis oversaw Taylor Wiseman and Taylor (TWT) survey the X, Y, and Z
coordinates of monitoring well MW-9 and MW-10. Based on the updated survey information and review of
updated potentiometric surface maps for the four most recent groundwater monitoring events, groundwater flow
direction has more of a westerly direction (Figures 4A through 4D). This would also indicate that monitoring wells
MW-9 and MW-10 are in a side-gradient direction from the source area.
Based on the attached Figure 3, the overall time versus concentration trend for monitoring well MW-9 appears to
be decreasing despite the seasonal fluctuations. It is expected the trend will continue to decrease over time.
It is also noted that the property to the south of the Site (The Former Arbor House; 605 West Market Street
Greensboro, Guilford County, North Carolina) where MW-10 is physically located has a Notice of Residual
Petroleum (NORP) (Attachment 2) attached to the property for petroleum constituents remaining on the property
and is an Underground Storage Tank (UST) incident under North Carolina’s Statutes and Regulations.
)LJXUHV
PROJECT
LOCATION
1 MILE RADIUS
0.5 MILE RADIUS
REFERENCE: BASE MAP USGS 7.5. MIN. TOPO. QUAD., GREENSBORO, NC, 1951, REVISED 1994. CONTOUR INTERVAL = 10 FEET
Approximate Scale: 1 in. = 2,000 ft.
0 2,000'4,000'
NORTH CAROLINA
SITE LOCATION MAP
FORMER EXXONMOBIL FACILITY #99-GRE
101 N SPRING STREETGREENSBORO, NORTH CAROLINA
1C:\Users\lposenauer\OneDrive - ARCADIS\BIM360 - OneDrive Sync Location\AUS-EXXON MOBIL-99 GRE-GREENSBORO North Carolina\2022\01-In Progress\01-DWG\GEN-F01-USGS SLM.dwg LAYOUT: 1 SAVED: 3/7/2022 1:57 PM ACADVER: 24.0S (LMS TECH) PAGESETUP: C-PA-PDFPLOTSTYLETABLE: PLTFULL.CTB PLOTTED: 3/7/2022 3:35 PM BY: POSENAUER, LISAAREA
LOCATION
FIGURE
MW-6MW-2
MW-7
DW-1MW-4
MW-1R
MW-8
MW-5
MW-3
MW-9
MW-10
F R I E N D L Y A V E N U E
W E S T M A R K E T S T R E
E

T N O R T H S P R I N G S T R E E TN O R T H C E D A RS T R E E TN/F
BACH LLC
PIN # 7864-46-2525
DB 6652 PG 2099
N/F
BFS RETAIL & COMMERCIAL
OPERATIONS LLC
PIN # 7864-46-5504
DB 5529 PG 1060
N/F
YOUNG MEN'S CHRISTIAN
ASSOC. OF GREENSBORO INC
PIN # 7864-46-5137
DB 4994 PG 434
N/F
GREENSBORO ARBOR PROP LLC
PIN # 7864-46-2270
DB 6549 PG 1097
N/F
MICHAEL T. WHALEN &
DEBORAH E. WHALEN
PIN # 7864-46-1271
DB 5999 PG 2167
N/F
GUILFORD COUNTY
BOARD OF EDUCATION
PIN # 7864-46-0282
DB 3841 PG 1518
N/F
GUILFORD COUNTY
BOARD OF EDUCATION
PIN # 7864-35-9919
DB 2804 PG 879
N/F
CONTEMPORARY
LANDSCAPES INC
PIN # 7864-36-9497
DB & PG N/A VIA GIS
N/F
SPRING STREET HOLDINGS LLC
PIN # 7864-36-9584
DB 6708 PG 1593
N/F
CITY OF GREENSBORO
BOARD OF ALCOHOL CONTROL
PIN # 7864-36-9634
DB 3729 PG 1609
N/F
BASIL AGAPION &
SOPHIA S. AGAPION
PIN # 7864-36-9870
DB 7093 PG 996
N/F
RONALD W. FINN &
JEANETTE R. FINN TRUST
PIN # 7864-46-1847
DB 6941 PG 1555
N/F
VM LLC
PIN # 7864-46-2846
DB 4737 PG 1800
N/F
RANDEL W. ROBERTS &
SHIRLEY M. ROBERTS
PIN # 7864-46-3836
DB 2798 PG 252
N/F
PARCEL INFORMATION N/A VIA GIS
PIN # N/A
DB & PG N/A
INLET
INLETS
INLETS INLETS
S
INLETINLET
INLETWWD
D
INLETD
D
INLETD
INLETD
D
D
D
INLET
INLETD
D
D
INLET
S
D
W
SITE MAP
XREFS: X-BASEFORMER EXXONMOBIL FACILITY #99-GRE
101 N SPRING STREETGREENSBORO, NORTH CAROLINA
C:\Users\lposenauer\OneDrive - ARCADIS\BIM360 - OneDrive Sync Location\AUS-EXXON MOBIL-99 GRE-GREENSBORO North Carolina\2022\01-In Progress\01-DWG\GEN-F02-SITE MAP.dwg LAYOUT: 2 SAVED: 3/7/2022 1:58 PM ACADVER: 24.0S (LMS TECH) PAGESETUP: C-PA-PDF PLOTSTYLETABLE:PLTFULL.CTB PLOTTED: 3/7/2022 3:35 PM BY: POSENAUER, LISA2
FIGURE
FIGURE
3
FORMER EXXONMOBIL FACILITY #99-GRE
101 N SPRING STREET
GREENSBORO, NORTH CAROLINA
Monitoring Well MW-9 Historical Analytical Data
- Benzene
LEGEND:
Benzene in µg/L (micrograms per liter)
DTW = groundwater elevation in feet
0
5,000
10,000
15,000
20,000
25,000
30,000
0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
800.00
900.00
Groundwater Elevation
NC 2B SW Std. (51 µg/L)
Benzene
Linear (Benzene)
DTW
Benzene
Date
F R I E N D L Y A V E N U E
W E S T M A R K E T S T R E
E

T N O R T H S P R I N G S T R E E TN O R T H C E D A RS T R E E TN/F
BACH LLC
PIN # 7864-46-2525
DB 6652 PG 2099
N/F
BFS RETAIL & COMMERCIAL
OPERATIONS LLC
PIN # 7864-46-5504
DB 5529 PG 1060
N/F
YOUNG MEN'S CHRISTIAN
ASSOC. OF GREENSBORO INC
PIN # 7864-46-5137
DB 4994 PG 434
N/F
GREENSBORO ARBOR PROP LLC
PIN # 7864-46-2270
DB 6549 PG 1097
N/F
MICHAEL T. WHALEN &
DEBORAH E. WHALEN
PIN # 7864-46-1271
DB 5999 PG 2167
N/F
GUILFORD COUNTY
BOARD OF EDUCATION
PIN # 7864-46-0282
DB 3841 PG 1518
N/F
GUILFORD COUNTY
BOARD OF EDUCATION
PIN # 7864-35-9919
DB 2804 PG 879
N/F
CONTEMPORARY
LANDSCAPES INC
PIN # 7864-36-9497
DB & PG N/A VIA GIS
N/F
SPRING STREET HOLDINGS LLC
PIN # 7864-36-9584
DB 6708 PG 1593
N/F
CITY OF GREENSBORO
BOARD OF ALCOHOL CONTROL
PIN # 7864-36-9634
DB 3729 PG 1609
N/F
BASIL AGAPION &
SOPHIA S. AGAPION
PIN # 7864-36-9870
DB 7093 PG 996
N/F
RONALD W. FINN &
JEANETTE R. FINN TRUST
PIN # 7864-46-1847
DB 6941 PG 1555
N/F
VM LLC
PIN # 7864-46-2846
DB 4737 PG 1800
N/F
RANDEL W. ROBERTS &
SHIRLEY M. ROBERTS
PIN # 7864-46-3836
DB 2798 PG 252
N/F
PARCEL INFORMATION N/A VIA GIS
PIN # N/A
DB & PG N/A
S
S
S
S
WW787.00MW-2
MW-7(784.11)
MW-1R
(787.92)
MW-8(787.40)
MW-5
MW-3
MW-10(786.96)
MW-6
(785.52)
MW-DW1
(787.28)*
MW-4(786.81)
MW-9(787.26)786.00785.00785.00786.00787.00S
D
W
(787.92)
*
POTENTIOMETRIC SURFACE MAP
JUNE 10, 2019
787.00
XREFS: X-BASEFORMER EXXONMOBIL FACILITY #99-GRE
101 N SPRING STREETGREENSBORO, NORTH CAROLINA
FIGURE
4AC:\Users\lposenauer\OneDrive - ARCADIS\BIM360 - OneDrive Sync Location\AUS-EXXON MOBIL-99 GRE-GREENSBORO North Carolina\2022\01-In Progress\01-DWG\GEN-F04A-POT SRF MAP-JUN2019.dwg LAYOUT: 4A SAVED: 3/7/2022 3:33 PM ACADVER: 24.0S (LMS TECH) PAGESETUP: C-PA-PDFPLOTSTYLETABLE: PLTFULL.CTB PLOTTED: 3/7/2022 3:35 PM BY: POSENAUER, LISA
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T N O R T H S P R I N G S T R E E TN O R T H C E D A RS T R E E TN/F
BACH LLC
PIN # 7864-46-2525
DB 6652 PG 2099
N/F
BFS RETAIL & COMMERCIAL
OPERATIONS LLC
PIN # 7864-46-5504
DB 5529 PG 1060
N/F
YOUNG MEN'S CHRISTIAN
ASSOC. OF GREENSBORO INC
PIN # 7864-46-5137
DB 4994 PG 434
N/F
GREENSBORO ARBOR PROP LLC
PIN # 7864-46-2270
DB 6549 PG 1097
N/F
MICHAEL T. WHALEN &
DEBORAH E. WHALEN
PIN # 7864-46-1271
DB 5999 PG 2167
N/F
GUILFORD COUNTY
BOARD OF EDUCATION
PIN # 7864-46-0282
DB 3841 PG 1518
N/F
GUILFORD COUNTY
BOARD OF EDUCATION
PIN # 7864-35-9919
DB 2804 PG 879
N/F
CONTEMPORARY
LANDSCAPES INC
PIN # 7864-36-9497
DB & PG N/A VIA GIS
N/F
SPRING STREET HOLDINGS LLC
PIN # 7864-36-9584
DB 6708 PG 1593
N/F
CITY OF GREENSBORO
BOARD OF ALCOHOL CONTROL
PIN # 7864-36-9634
DB 3729 PG 1609
N/F
BASIL AGAPION &
SOPHIA S. AGAPION
PIN # 7864-36-9870
DB 7093 PG 996
N/F
RONALD W. FINN &
JEANETTE R. FINN TRUST
PIN # 7864-46-1847
DB 6941 PG 1555
N/F
VM LLC
PIN # 7864-46-2846
DB 4737 PG 1800
N/F
RANDEL W. ROBERTS &
SHIRLEY M. ROBERTS
PIN # 7864-46-3836
DB 2798 PG 252
N/F
PARCEL INFORMATION N/A VIA GIS
PIN # N/A
DB & PG N/A
S
S
S
S
WW787.00MW-2
MW-7(783.81)
MW-1R(787.78)
MW-8
(787.09)
MW-5
MW-3
MW-10(786.15)
MW-6
(785.38)
MW-DW1
(786.65)*
MW-4(786.64)
MW-9
(786.98)786.00785.00785.00786.00787.00784.00784.00S
D
W
(787.78)
*
POTENTIOMETRIC SURFACE MAP
SEPTEMBER 18, 2019
787.00
XREFS: X-BASEFORMER EXXONMOBIL FACILITY #99-GRE
101 N SPRING STREETGREENSBORO, NORTH CAROLINA
FIGURE
4BC:\Users\lposenauer\OneDrive - ARCADIS\BIM360 - OneDrive Sync Location\AUS-EXXON MOBIL-99 GRE-GREENSBORO North Carolina\2022\01-In Progress\01-DWG\GEN-F04B-POT SRF MAP-SEPT2019.dwg LAYOUT: 4B SAVED: 3/7/2022 3:34 PM ACADVER: 24.0S (LMS TECH) PAGESETUP: C-PA-PDFPLOTSTYLETABLE: PLTFULL.CTB PLOTTED: 3/7/2022 3:35 PM BY: POSENAUER, LISA
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T N O R T H S P R I N G S T R E E TN O R T H C E D A RS T R E E TN/F
BACH LLC
PIN # 7864-46-2525
DB 6652 PG 2099
N/F
BFS RETAIL & COMMERCIAL
OPERATIONS LLC
PIN # 7864-46-5504
DB 5529 PG 1060
N/F
YOUNG MEN'S CHRISTIAN
ASSOC. OF GREENSBORO INC
PIN # 7864-46-5137
DB 4994 PG 434
N/F
GREENSBORO ARBOR PROP LLC
PIN # 7864-46-2270
DB 6549 PG 1097
N/F
MICHAEL T. WHALEN &
DEBORAH E. WHALEN
PIN # 7864-46-1271
DB 5999 PG 2167
N/F
GUILFORD COUNTY
BOARD OF EDUCATION
PIN # 7864-46-0282
DB 3841 PG 1518
N/F
GUILFORD COUNTY
BOARD OF EDUCATION
PIN # 7864-35-9919
DB 2804 PG 879
N/F
CONTEMPORARY
LANDSCAPES INC
PIN # 7864-36-9497
DB & PG N/A VIA GIS
N/F
SPRING STREET HOLDINGS LLC
PIN # 7864-36-9584
DB 6708 PG 1593
N/F
CITY OF GREENSBORO
BOARD OF ALCOHOL CONTROL
PIN # 7864-36-9634
DB 3729 PG 1609
N/F
BASIL AGAPION &
SOPHIA S. AGAPION
PIN # 7864-36-9870
DB 7093 PG 996
N/F
RONALD W. FINN &
JEANETTE R. FINN TRUST
PIN # 7864-46-1847
DB 6941 PG 1555
N/F
VM LLC
PIN # 7864-46-2846
DB 4737 PG 1800
N/F
RANDEL W. ROBERTS &
SHIRLEY M. ROBERTS
PIN # 7864-46-3836
DB 2798 PG 252
N/F
PARCEL INFORMATION N/A VIA GIS
PIN # N/A
DB & PG N/A
S
S
S
S
WWMW-2
MW-7
(783.95)
MW-1R
(787.73)
MW-8(787.21)
MW-5
MW-3
MW-10(786.83)
MW-6(785.16)
DW-1
(786.74)*
MW-4(786.76)
MW-9
(786.95)785.00784.00785.00784.00787.00786.00786.00787.00S
D
W
(787.73)
*
POTENTIOMETRIC SURFACE MAP
MARCH 24, 2020
787.00
XREFS: X-BASEFORMER EXXONMOBIL FACILITY #99-GRE
101 N SPRING STREETGREENSBORO, NORTH CAROLINA
FIGURE
4CC:\Users\lposenauer\OneDrive - ARCADIS\BIM360 - OneDrive Sync Location\AUS-EXXON MOBIL-99 GRE-GREENSBORO North Carolina\2022\01-In Progress\01-DWG\GEN-F04C-POT SRF MAP-MAR2020.dwg LAYOUT: 4C SAVED: 3/7/2022 2:10 PM ACADVER: 24.0S (LMS TECH) PAGESETUP: C-PA-PDFPLOTSTYLETABLE: PLTFULL.CTB PLOTTED: 3/7/2022 3:35 PM BY: POSENAUER, LISA
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T N O R T H S P R I N G S T R E E TN O R T H C E D A RS T R E E TN/F
BACH LLC
PIN # 7864-46-2525
DB 6652 PG 2099
N/F
BFS RETAIL & COMMERCIAL
OPERATIONS LLC
PIN # 7864-46-5504
DB 5529 PG 1060
N/F
YOUNG MEN'S CHRISTIAN
ASSOC. OF GREENSBORO INC
PIN # 7864-46-5137
DB 4994 PG 434
N/F
GREENSBORO ARBOR PROP LLC
PIN # 7864-46-2270
DB 6549 PG 1097
N/F
MICHAEL T. WHALEN &
DEBORAH E. WHALEN
PIN # 7864-46-1271
DB 5999 PG 2167
N/F
GUILFORD COUNTY
BOARD OF EDUCATION
PIN # 7864-46-0282
DB 3841 PG 1518
N/F
GUILFORD COUNTY
BOARD OF EDUCATION
PIN # 7864-35-9919
DB 2804 PG 879
N/F
CONTEMPORARY
LANDSCAPES INC
PIN # 7864-36-9497
DB & PG N/A VIA GIS
N/F
SPRING STREET HOLDINGS LLC
PIN # 7864-36-9584
DB 6708 PG 1593
N/F
CITY OF GREENSBORO
BOARD OF ALCOHOL CONTROL
PIN # 7864-36-9634
DB 3729 PG 1609
N/F
BASIL AGAPION &
SOPHIA S. AGAPION
PIN # 7864-36-9870
DB 7093 PG 996
N/F
RONALD W. FINN &
JEANETTE R. FINN TRUST
PIN # 7864-46-1847
DB 6941 PG 1555
N/F
VM LLC
PIN # 7864-46-2846
DB 4737 PG 1800
N/F
RANDEL W. ROBERTS &
SHIRLEY M. ROBERTS
PIN # 7864-46-3836
DB 2798 PG 252
N/F
PARCEL INFORMATION N/A VIA GIS
PIN # N/A
DB & PG N/A
S
S
S
S
WWMW-2
MW-7(783.82)
MW-1R
(792.50)
MW-8(786.90)MW-5
MW-3
MW-10(786.80)
MW-6(785.33)
DW-1
(786.51)*
MW-4(786.54)
MW-9
(786.81)786.00784.00788.00
786.00784.00792.00790.00792.00788.00790.00S
D
W
POTENTIOMETRIC SURFACE MAP
NOVEMBER 11, 2020
792.00
XREFS: X-BASEFORMER EXXONMOBIL FACILITY #99-GRE
101 N SPRING STREETGREENSBORO, NORTH CAROLINA
(792.50)
FIGURE
4DC:\Users\lposenauer\OneDrive - ARCADIS\BIM360 - OneDrive Sync Location\AUS-EXXON MOBIL-99 GRE-GREENSBORO North Carolina\2022\01-In Progress\01-DWG\GEN-F04D-POT SRF MAP-NOV2020.dwg LAYOUT: 4D SAVED: 3/7/2022 2:15 PM ACADVER: 24.0S (LMS TECH) PAGESETUP: C-PA-PDFPLOTSTYLETABLE: PLTFULL.CTB PLOTTED: 3/7/2022 3:35 PM BY: POSENAUER, LISA*
Tables
Table 1
Dissolved-Phase VOC Concentrations in Groundwater
Former Exxon Mobil Facility #99-GRE
Incident Number 20003
Well or SW
ID
Date
Collected
(mm/dd/yr) Sample ID
Incident
Phase
1,400 NE NE 51 11 97 670 1,500 320 13,000 NE 140 170 2.2 NE 15 37 15 NE NE NE 330 3 3,200 NE 390 630 0.31
NE NE NE 5,000 260,000 84,500 85,500 20,000 25,000 70,000 NE 50,000 70,000 170 NE 6,000 400 600 6,900 15,000 8,500 6,000 NE 30,000 70,000 28,500 25,000 50
MW-1 5/15/2002 MW-1 Monitoring 28,000 8,500 ND 9,700 12,000 1,500 7,500 ND --930 ----ND ND --78 --------92 ND --------35
10/16/2003 Monitoring 109,000 17,900 4,790 29,800 20,600 1,980 10,100 680 --1,060 ----<250 43.0 --<250 --------91.0 <10 --------168
1/2/2006 Monitoring 90,800 16.1 5.19 22,400 17,200 1,810 11,430 1,900 --1,600 --ND ND ND 0.95 ND ND --------------------
10/3/2006 Monitoring 27,100 ND 3610 21,700 20,800 1,920 15,000 ND --518 --ND ND ND ND --ND ND ------188 ------------
10/25/2007 Monitoring 77,000 12300 4430 18,600 10,500 1,340 4,970 ND --331 --ND ND ND ND --ND 21.9 ------106 ------------
10/13/2008 Monitoring 58,400 12900 4420 7,260 10,600 938 6,750 ND --331 --ND ND ND ND --ND 21.9 ------39.2 ------------
8/12/2009 Monitoring 6,690 830 299 310 805 67.8 667 < 0.500 --4.95 --< 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 ------5.05 ------------
8/9/2010 Monitoring ------3,180 6,920 625 4,000 < 0.500 24.1 51.5 4.96 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 14.1 1.11 2.6 50.2 --43.4 --526 230 --
11/22/2010 Monitoring ------5,520 10,500 1,230 8,620 < 0.500 92.5 106 25.5 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 93 < 0.500 < 0.500 252 --206 < 0.500 2,210 884 48
2/26/2011 NUC0168-01 Monitoring ------14,900 18,900 1,980 9,670 < 0.500 75.8 198 12.7 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 32.5 1.98 7.6 158 --130 80.1 1,440 517 70.1
4/22/2011 NUD3901-01 Monitoring ------10,600 11,900 1,570 8,340 0.67 86.3 167 14.6 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 43.0 2.32 9.44 160 --165 81.0 1,620 644 59.4
10/25/2011 NUJ3226-02 Monitoring ------17,500 21,200 1,600 7,740 < 0.500 57.5 264 5.87 < 0.500 < 0.500 --< 0.500 < 0.500 < 0.500 < 0.500 11.2 1.07 3.35 114 --83.4 127 847 302 42.4
3/15/2012 Monitoring ------15,000 11,100 1,370 6,340 < 10.0 53.4 217 < 10.0 < 10.0 < 10.0 --< 10.0 < 10.0 < 10.0 < 10.0 13.8 < 10.0 < 10.0 106 --87.6 < 10.0 763 283 26.8
8/14/2012 Monitoring 108,000 21,200 2,740 11+E7+H21 15,400 1,370 7,480 < 0.500 59.7 186 8.43 < 0.500 < 0.500 --< 0.500 < 0.500 < 0.500 19.8 20.6 1.32 4.43 119 --99.3 < 0.500 874 325 29.6
3/14/2013 Monitoring ------4,950 8,940 1,120 6,200 < 0.500 50.2 40.1 8.95 < 0.500 < 0.500 --< 0.500 < 0.500 < 0.500 < 0.500 22.4 1.44 6.49 99.1 --98.3 < 0.500 843 352 < 0.500
9/20/2013 Monitoring ------11,600 10,200 1,530 8,050 <10.0 50.7 148 <10.0 <10.0 <10.0 --<10.0 <10.0 <10.0 <10.0 17.3 <10.0 <10.0 <100 --101 <10.0 920 352 15.4
3/25/2014 490-49450-1 Monitoring ------11,000 7,840 1,590 8,620 <10.0 56.6 151 <10.0 <10.0 <10.0 23.1 <10.0 <10.0 120 107 1,060 434 <10.0
9/24/2014 490-62265-1 Monitoring ------13,200 15,900 1,630 9,000 <10.0 51.6 203 <10.0 <10.0 13.9 16.6 <10.0 <10.0 104 96.5 994 389 <10.0
3/18/2015 490-74765-1 Monitoring ------10,700 11,700 1,700 9,180 <10.0 53.1 141 <10.0 <10.0 <10.0 118 91.8 1,020 433 17.3
9/10/2015 490-87114-1 Monitoring ------13,500 16,200 1,670 9,130 <10.0 45.6 189 <10.0 12.6 21.3 <100 86.6 1,060 424 13.8
8/11/2016 490-109742-1 Monitoring ------13,300 9,010 1,830 11,000 <10.0 59.1 162 <10.0 <10.0 23.6 125 109.0 1,110 463 <10.0
9/15/2017 9213047 Monitoring ------14,000 5,100 1,800 9,100 <100 <100 190 <100 <100 <100 --<100 <100 <100 <100 <100 <100 <100 110 --<100 <100 990 360 <100
12/14/2018 9943002 Monitoring ------8,400 9,600 1,500 8,300 <50 61 120 <100 <100 <100 --<100 <100 <50 <50 <50 <100 <100 120 --100 <100 930 590 <50
3/29/2019 Monitoring ------2,800 4,400 640 4,700 <50 <50 100 <100 <100 <100 --<100 <100 <50 <50 <50 <100 <100 51 --51 <100 520 320 <50
6/10/2019 1078827 Monitoring ------1,700 4,200 690 4,500 <50 <50 <50 < 50 < 50 < 50 --< 50 < 50 <50 <50 <50 --< 50 53 --58 < 50 560 300 <50
9/18/2019 1155383 Monitoring ------68 330 53 1,200 <5.0 <5.0 18 <5.0 <5.0 <5.0 --<5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 5 --<5.0 <5.0 190 130 <5.0
3/24/2020 1288375 Monitoring ------110 630 150 1,600 <5.0 9.5 <5.0 <5.0 <5.0 <5.0 --<5.0 <5.0 <5.0 <5.0 <5.0 <5.0 <5.0 16 --14 <5.0 250 140 <5.0
11/11/2020 410-20956-1 Monitoring ------1.8 2.0 <0.50 10 <0.50 <0.50 --<0.50 <0.50 <0.50 --<0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 --<0.50 <0.50 0.5 0.84 <0.50
MW-2 5/15/2002 MW-2 Monitoring 570 ND ND ND ND ND ND ND --1,400 ----ND ND ----93 --------ND ND --------ND
MW-3 5/15/2002 MW-3 Monitoring ND ND ND ND ND ND ND ND --ND ----ND ND ----ND --------ND ND --------ND
10/16/2003 Monitoring 10,000 1,620 1,000 1,140 135 299 479 32.0 --1,360 ----<0.5 <10 ----<0.5 --------40.0 <10 --------<0.02
1/2/2006 Monitoring 1.16 0.25 0.165 1,310 47.3 403 297.7 84.4 --17.8 --9.7 ND ND ND --ND 2.09 --------------------
10/3/2006 Monitoring 6,890 ND 518 1,080 136 337 288 ND --1,910 --ND ND ND ND --ND ND ------60.2 ------------
10/25/2007 Monitoring 4,900 847 ND 627 10.2 96.5 42.8 ND --1,200 --ND ND ND ND --ND ND ------31.1 ------------
10/13/2008 Monitoring 7,600 1,110 771 1,210 19.8 357 253 2.76 --981 --ND ND ND ND --ND ND ------85.4 ------------
8/12/2009 Monitoring 25,900 2,940 <2,000 2,250 40.7 457 298 < 0.500 --981 --< 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 ------98.9 ------------
8/9/2010 Monitoring ------8,590 97.1 4,580 1,800 < 0.500 105 730 9.27 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 36.2 2.21 10.5 499 --263 --1,040 147 --
11/22/2010 Monitoring ------3,070 155 192 305 < 0.500 10.8 504 2.62 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 5.38 1.49 1.72 55.1 --14.2 7.49 54 41.9 < 0.500
2/26/2011 NUC0168-02 Monitoring ------5,200 80.3 1,220 763 < 0.500 60.8 541 5.69 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 13.4 2.1 6.58 275 --99.8 2.46 189 43.2 < 0.500
4/22/2011 NUD3901-02 Monitoring ------4,870 87.6 527 193 < 0.500 43.1 1,040 6.55 2.40 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 10.3 2.64 6.30 120 --54 < 0.500 73.7 23.1 < 0.500
10/25/2011 NUJ3226-01 Monitoring ------4,560 63.6 477 205 1.14 35.2 1,320 3.04 < 0.500 < 0.500 --< 0.500 0.550 <0.500 < 0.500 6.71 1.84 4.50 138 --45.1 < 0.500 78.4 14.6 < 0.500
3/15/2012 Monitoring ------4,390 75.8 399 172 < 2.50 36.6 1,280 4.35 < 2.50 < 2.50 --< 2.50 < 2.50 < 2.50 < 2.50 6.45 < 2.50 5.40 112 --44.0 < 2.50 63.1 12.7 < 2.50
8/14/2012 Monitoring 29,200 2,540 < 1,000 4,130 75.2 560 238 < 0.500 51.0 1,470 4.76 < 0.500 < 0.500 --< 0.500 < 0.500 < 0.500 < 0.500 10.8 2.60 7.08 182 --66.7 1.47 73.9 14.6 < 0.500
3/14/2013 Monitoring ------3,260 73.5 336 114 <0.500 32.5 1,220 5.28 <0.500 <0.500 --<0.500 <0.500 <0.500 <0.500 8.13 2.5 5.97 93.9 --41.7 <0.500 28.6 10.6 <0.500
9/20/2013 Monitoring 4,680 76.0 361 101 <2.5 34.1 1,540 5.61 <2.5 <2.5 --<2.5 <2.5 <2.5 <2.5 7.25 <2.5 5.41 82.4 --39.4 <2.5 8.62 10.0 <2.50
3/25/2014 490-49450-2 Monitoring ------1,970 42.5 265 73.7 <2.50 22.9 767 3.29 <2.50 <2.50 6.79 <2.50 3.86 64.4 35.2 13.8 5.01 <2.50
9/24/2014 490-62265-2 Monitoring ------5,110 81.8 374 106 <2.50 36.8 1,740 4.71 <2.50 <2.50 7.46 <2.50 5.42 103 44.7 7.54 7.26 <2.50
3/18/2015 490-74765-2 Monitoring ------2,310 41.6 239 68.5 <2.50 22.3 1,230 <2.50 <2.50 <2.50 66.8 28.9 6.71 4.33 <2.50
9/10/2015 490-87114-2 Monitoring ------4,070 59.5 378 119 <2.50 33.3 1,660 <2.50 <2.50 6.47 81.4 43.9 10.5 5.98 <2.50
8/11/2016 490-109742-2 Monitoring ------4,140 57.2 532 144 <2.50 38.8 1,460 <2.50 <2.50 11.8 141 72.3 13.1 5.87 <2.50
9/15/2017 9213048 Monitoring ------1,400 26.0 130 48 <25 <25 1,100 <25 <25 <25 --<25 <25 <25 <25 <25 <25 <25 36 --<25 <25 <25 <25 <25
12/14/2018 9943003 Monitoring ------440 9.7 220 43 <5.0 15 310 <25 <25 <25 --<25 <25 <5.0 <5.0 <5.0 <25 <25 31 --35 <25 22 5.70 <5.0
3/29/2019 Monitoring ------660 19.0 210 48 <5.0 13 570 <25 <25 <25 --<25 <25 <5.0 <5.0 <5.0 <25 <25 43 --23 <25 9.5 <5.0 <5.0
6/10/2019 1078828 Monitoring ------3,100 57 380 130 <50 <50 1,200 < 50 < 50 < 50 --< 50 < 50 <50 <50 <50 --< 50 93 --<50 < 50 <50 <50 <50
9/18/2019 1155384 Monitoring ------4,000 62 470 140 <25 33 1,400 <25 <25 <25 --<25 <25 <25 <25 <25 <25 <25 99 --50 <25 <25 <25 <25
3/24/2020 1288378 Monitoring ------2,200 43.0 740 130 <25 37 720 <25 <25 <25 --<25 <25 <25 <25 <25 <25 <25 120 --89 <25 28 <25 <25
11/13/2020 410-20956-2 Monitoring ------3,200 48 490 82 <25 <25 --<25 <25 <25 --<25 <25 <25 <25 <25 <25 <25 75 --46 <25 <25 <25 <25
10/16/2003 Monitoring 169 <100 <100 24.6 31.5 3.4 17.3 <1 --7.7 ----<0.5 <10 ----<0.5 --------<10 <10 --------0.18
1/2/2006 Monitoring ND ND ND ND ND ND ND ND --9.3 --ND ND ND ND --5.78 ND --------------------
10/3/2006 Monitoring ND ND ND ND ND ND ND ND --5.5 --0.98 ND ND ND --3.2 ND ------ND ------------
10/25/2007 Monitoring
MW-1R
MW-4 BromomethaneMW-4
MW-1R
MW-1R
MW-4 BenzeneEthylbenzeneMTBEXylenesp-IsopropyltolueneChloroformn-NitrosodimethylamineBis(2-ethylhexyl)phthalateStyrene1,2-DichloroethaneWell Abandoned
MW-5 Diisopropyl EtherContaminant of Concern →
NC 2B Surface Water Standards tert- ButylbenzeneEDB1,2,4-Trimethylbenzenen-ButylbenzeneAnalytical Methods →C9-C10 AliphaticsIsopropylbenzeneChlorobenzene1,3,5-Trimethylbenzenen-PropylbenzeneNaphthalenesec-ButylbenzeneToluene1,2-DichloropropaneC9-C12 Aliphatics(Uandjusted)Gross Contaminant Levels (GCL)
MW-5 1,1-DichloroethaneMADEP VPH
(historical data used VPH/EPH)C5-C8 Aliphatics(Unadjusted)1/2
Table 1
Dissolved-Phase VOC Concentrations in Groundwater
Former Exxon Mobil Facility #99-GRE
Incident Number 20003
Well or SW
ID
Date
Collected
(mm/dd/yr) Sample ID
Incident
Phase
1,400 NE NE 51 11 97 670 1,500 320 13,000 NE 140 170 2.2 NE 15 37 15 NE NE NE 330 3 3,200 NE 390 630 0.31BromomethaneBenzeneEthylbenzeneMTBEXylenesp-IsopropyltolueneChloroformn-NitrosodimethylamineBis(2-ethylhexyl)phthalateStyrene1,2-DichloroethaneDiisopropyl EtherContaminant of Concern →
NC 2B Surface Water Standards tert- ButylbenzeneEDB1,2,4-Trimethylbenzenen-ButylbenzeneAnalytical Methods →C9-C10 AliphaticsIsopropylbenzeneChlorobenzene1,3,5-Trimethylbenzenen-PropylbenzeneNaphthalenesec-ButylbenzeneToluene1,2-DichloropropaneC9-C12 Aliphatics(Uandjusted)1,1-DichloroethaneMADEP VPH
(historical data used VPH/EPH)C5-C8 Aliphatics(Unadjusted)8/14/2012 Monitoring 1,700 < 100 < 100 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 1.00 795 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 13.8 < 0.500 < 0.500 < 0.500 < 0.500 < 5.00 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500
8/11/2016 Monitoring ------<0.500 <0.500 <0.500 <1.00 <0.500 <1.00 455 5.08 <0.500 <0.500 <5.00 <0.500 <0.500 <0.500 <0.500
9/15/2017 9213049 Monitoring ------<0.500 <0.500 <0.500 <0.500 <0.500 <0.500 460 <0.500 <0.500 <0.500 --<0.500 <0.500 4.6 <0.500 <0.500 <0.500 <0.500 <0.500 --<0.500 <0.500 <0.500 <0.500 <0.500
12/14/2018 9943004 Monitoring ------<5.0 <5.0 <5.0 <5.0 <5.0 <5.0 400 <0.500 <0.500 <0.500 --<0.500 <0.500 <5.0 <5.0 <5.0 <0.500 <0.500 <5.0 --<5.0 <0.500 <5.0 <5.0 <5.0
3/29/2019 Monitoring ------<5.0 <5.0 <5.0 <5.0 <5.0 <5.0 360 <0.500 <0.500 <0.500 --<0.500 <0.500 <5.0 <5.0 <5.0 <0.500 <0.500 <5.0 --<5.0 <0.500 <5.0 <5.0 <5.0
6/10/2019 1078829 Monitoring ------<2.5 <2.5 <2.5 <2.5 <2.5 <2.5 310 < 2.5 < 2.5 < 2.5 --< 2.5 < 2.5 3.5 <2.5 <2.5 --< 2.5 <2.5 --<2.5 < 2.5 <2.5 <2.5 <2.5
9/18/2019 1155385 Monitoring ------<2.5 <2.5 <2.5 <5.0 <2.5 <2.5 320 <2.5 <2.5 <2.5 --<2.5 <2.5 5 <2.5 <2.5 <2.5 <2.5 <2.5 --<2.5 <2.5 <2.5 <2.5 <2.5
3/24/2020 1288377 Monitoring ------<2.5 <2.5 <2.5 <5.0 <2.5 <2.5 290 <2.5 <2.5 <2.5 --<2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 --<2.5 <2.5 <2.5 <2.5 <2.5
11/13/2020 410-20956-3 Monitoring ------<2.5 <2.5 <2.5 <5.0 <2.5 <2.5 --<2.5 <2.5 <2.5 --<2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 <2.5 --<2.5 <2.5 <2.5 <2.5 <2.5
8/14/2012 MW-7 Monitoring 196 < 100 < 100 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 1.00 105 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 5.00 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500
3/25/2020 1288380 Monitoring ------<1.0 <1.0 <1.0 <2.0 <1.0 <1.0 30 <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 <1.0 <1.0
11/13/2020 410-20956-4 Monitoring ------<1.0 <1.0 <1.0 <2.0 <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 <1.0 <1.0 <1.0 <1.0
MW-8 8/14/2012 MW-8 Monitoring < 100 < 100 < 100 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 1.00 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 5.00 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500
3/25/2014 490-49450-3 Monitoring ------24,200 24,300 1,810 11,700 <5.00 64.6 67.2 8.85 <5.00 19.9 26.5 <5.00 8.37 241 142 1,230 445 68.1
9/24/2014 490-62265-3 Monitoring ------18,400 26,900 1,790 11,400 <10.0 56.1 128 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 16.6 19.5 <10.0 <10.0 212 118 1,100 381 51.4
3/18/2015 490-74765-3 Monitoring ------20,500 23,600 1,860 12,200 <10.0 66.8 118 <10.0 24.1 <10.0 248 141 1,240 474 53.8
9/10/2015 490-87114 Monitoring ------21,200 26,700 1,760 12,100 <10.0 46.9 119 <10.0 <10.0 22.3 153 99.8 1,130 417 49.8
8/11/2016 490-109732-4 Monitoring ------20,900 24,700 1,730 12,900 <10.0 56.4 93.1 <10.0 17.5 24.8 211 115 1,040 395 <10.0
9/15/2017 9213050 Monitoring ------6,100 11,000 1,100 7,100 <50.0 <50.0 <50.0 <50.0 <50.0 <50.0 --<50.0 <50.0 <50.0 <50.0 <50.0 <50.0 <50.0 140 <50.0 75 210 800 300 <50.0
12/14/2018 9943005 Monitoring ------11,000 16,000 1,000 9,300 <50 <50 <50 <50 <50 <50 <50 <50 <50 <50 <50 <50 <50.0 <50.0 190 <50.0 58 210 970 370 <50
3/29/2019 Monitoring ------460 410 33 4,800 <25 <25 49 <50 <50 <50 <50 <50 <50 <25 <25 <25 <50.0 <50.0 52 <50.0 <25 210 500 260 <25
6/10/2019 1078830 Monitoring ------63 420 64 1,800 <5.0 <5.0 <5.0 < 5.0 < 5.0 < 5.0 --< 5.0 < 5.0 <5.0 <5.0 <5.0 --< 5.0 28 --6.5 < 5.0 280 180 <5.0
6/10/2019 1078832*Monitoring ------64 430 65 1,800 <5.0 <5.0 <5.0 < 5.0 < 5.0 < 5.0 --< 5.0 < 5.0 <5.0 <5.0 <5.0 --< 5.0 27 --6.6 < 5.0 250 170 <5.0
9/18/2019 1155386 Monitoring ------830 2,600 200 3,700 <25 <25 25 <25 <25 <25 --<25 <25 <25 <25 <25 <25 <25 54 --<25 <25 320 160 <25
9/18/2019 1155388*Monitoring ------850 2,600 210 3,600 <25 <25 <25 <25 <25 <25 --<25 <25 <25 <25 <25 <25 <25 56 --<25 <25 330 170 <25
3/24/2020 1288376 Monitoring ------3,200 5,700 470 5,500 <25 <25 38 <25 <25 <25 --<25 <25 <25 <25 <25 <25 <25 76 --<25 <25 520 270 <25
11/13/2020 410-20956-5 Monitoring ------3,200 4,300 430 4,000 <25 <25 --<25 <25 <25 --<25 <25 <25 <25 <25 <25 <25 57 --<25 <25 360 190 <25
8/11/2016 490-109742-5 Monitoring ------<0.500 <0.500 <0.500 <1.00 <0.500 <1.00 <0.500 <0.500 <0.500 <0.500 <5.00 <0.500 <0.500 <0.500 <0.500
9/15/2017 9213051 Monitoring ------<0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500 <5.00 <0.500 <0.500 <0.500 <0.500 <0.500 <0.500
12/14/2018 9943006 Monitoring ------<0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.12 <0.13 <0.14 <0.15 <0.16 <0.17 <0.5 <0.5 <0.5 <0.21 <0.22 <0.5 <0.24 <0.5 <0.26 <0.5 <0.5 <0.5
3/29/2019 Monitoring ------<0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.12 <0.13 <0.14 <0.15 <0.16 <0.17 <0.5 <0.5 <0.5 <0.21 <0.22 <0.5 <0.24 <0.5 <0.26 <0.5 <0.5 <0.5
6/10/2019 1078831 Monitoring ------<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 <0.5 --<0.5 < 0.5 <0.5 <0.5 <0.5
9/18/2019 1155387 Monitoring ------<0.5 <0.5 <0.5 <1.0 <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 <0.5 <0.5 <0.5
3/25/2020 1288379 Monitoring ------<0.5 <0.5 <0.5 <1.0 <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 <0.5 <0.5 <0.5
11/13/2020 410-20956-6 Monitoring ------<0.50 <0.50 <0.50 <1.0 <0.50 <0.50 --<0.50 <0.50 <0.50 --<0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 --<0.50 <0.50 <0.50 <0.50 <0.50
10/16/2003 Monitoring 1,370 157 <100 64.1 115 14.0 66.3 2.5 --118 ----2.40 <10 ----<0.5 --------<10 25.0 --------0.48
1/2/2006 Monitoring 292 ND ND ND ND ND 3.21 ND --46.7 --ND ND ND ND --ND ND --------------------
10/3/2006 Monitoring 307 285 ND 19.5 93.8 16 94.1 ND --33 --ND ND ND ND --2.45 ND ------7.79 ------------
10/25/2007 Monitoring ND ND ND 3.34 ND 5.25 4.42 ND --11.5 --ND ND ND ND --1.59 ND ------ND ------------
8/9/2010 Monitoring ------< 0.500 < 0.500 < 0.500 < 1.00 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500 ND<5.00 --< 0.500 --< 0.500 < 0.500 --
11/22/2010 Monitoring ------< 0.500 < 0.500 < 0.500 < 1.00 < 0.500 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500 ND<5.00 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500
2/26/2011 NUC0168-03 Monitoring ------< 0.500 < 0.500 < 0.500 < 1.00 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 5.00 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500
08/14/12 DW-1 Monitoring 130 < 100 < 100 < 0.500 < 0.500 < 0.500 < 0.500 < 0.500 < 1.00 14.2 < 0.500 < 0.500 < 0.500 --< 0.500 --1.09 < 0.500 < 0.500 < 0.500 < 0.500 < 5.00 --< 0.500 < 0.500 < 0.500 < 0.500 < 0.500
Notes:
Results reported in µg/L (micrograms per liter)
--: Not Analyzed for specific compound
< #: Non-detect above laboratory reporting limit
ND: Non-detect above laboratory reporting limit where laboratory reporting limit not available from historical data
Bold: Exceeds NC 2B Surface Water Standards
Shaded: Exceeds Gross Contaminant Levels (GCL)
MTBE: Methyl tert-Butyl Ether
IPE: Diisopropyl Ether
EDB: 1, 2 Dibromoethane
*: Second sample for MW-9 collected as DUP-01
MW-10
MW-6
MW-6
MW-7
MW-9
DW-1
DW-1
2/2
Table 2
Groundwater Elevation Data
Former ExxonMobile Facility #99-GRE
Incident Number 20003
Monitor Well
I.D.
Date
Installed
Date Water
Level
Measured
Well Casing
Diameter
(inches)
Well Casing
Depth
(feet bgs)
Screened
Interval
(feet bgs)
Bottom of
Well
(feet bgs)
Relative
Top of
Casing
Elevation
(feet)
Depth to
Water from
Top of
Casing
(feet)
Free
Product
Thickness
(feet)
Relative
Groundwater
Elevation
(feet)
5/15/2002 1 0-15 15-30 30 100.14 15.42 0.00 84.72
1/12/2004
1/13/2004 12.80 0.00 87.20
10/3/2006 13.65 0.00 86.35
10/25/2007 17.00 0.00 83.00
10/13/2008 11.63 0.00 88.37
8/12/2009 12.63 0.00 87.37
2/4/2010 12.54 0.00 87.46
8/9/2010 13.19 0.00 86.81
8/10/2010 13.23 0.00 86.77
11/22/2010 13.35 0.00 86.65
2/26/2011 15.00 0.00 85.00
4/22/2011 14.45 0.00 85.55
5/23/2011 14.27 0.00 85.73
10/25/2011 14.32 0.00 85.68
3/15/2012 14.46 0.00 85.54
8/14/2012 14.91 0.00 784.89
3/14/2013 14.51 0.00 785.29
9/20/2013 13.32 0.00 786.48
3/25/2014 13.22 0.00 786.58
9/24/2014 14.18 0.00 785.62
3/18/2015 14.38 0.00 785.42
9/10/2015 14.35 0.00 785.45
8/11/2016 12.97 0.00 786.83
9/15/2017 14.16 0.00 785.64
12/14/2018 11.92 0.00 787.88
3/29/2019 11.21 0.00 788.59
6/10/2019 11.88 0.00 787.92
9/18/2019 12.02 0.00 787.78
3/24/2020 12.07 0.00 787.73
11/11/2020 7.30 0.00 792.50
5/15/2002 9.75 0.00 83.45
1/13/2004 8.40 0.00 84.80
5/15/2002 14.11 0.00 81.25
1/13/2004 12.20 0.00 83.16
10/16/2003 9.55 0.00 87.42
1/13/2004 10.55 0.00 86.42
1/2/2006 12.10 0.00 84.87
10/3/2006 11.58 0.00 85.39
10/25/2007 15.37 0.00 81.60
10/13/2008 11.78 0.00 85.19
8/12/2009 11.00 0.00 85.97
2/4/2010 14.63 0.00 82.34
8/9/2010 12.38 0.00 84.59
8/10/2010 13.23 0.00 83.74
11/22/2010 13.44 0.00 83.53
2/26/2011 13.90 0.00 83.07
4/22/2011 13.60 0.00 83.37
5/23/2011 13.40 0.00 83.57
10/25/2011 13.56 0.00 83.41
3/15/2012 13.59 0.00 83.38
8/14/2012 13.15 0.00 785.34
3/14/2013 13.72 0.00 784.77
9/20/2013 12.57 0.00 785.92
3/25/2014 12.42 0.00 786.07
9/24/2014 13.38 0.00 785.11
3/18/2015 13.57 0.00 784.92
9/10/2015 13.36 0.00 785.13
8/11/2016 12.35 0.00 786.14
9/15/2017 13.46 0.00 785.03
12/14/2018 11.91 0.00 786.58
3/29/2019 10.90 0.00 787.59
6/10/2019 11.68 0.00 786.81
9/18/2019 11.85 0.00 786.64
3/24/2020 11.73 0.00 786.76
11/11/2020 11.95 0.00 786.54
799.80
MW-4 10/15/03 4 0-7 7-22 22
798.49
Destroyed
5-20
95.36
200-5
0-4
MW-2 5/13/02
96.97
1
MW-3 5/13/02 14
Destroyed
1 4-14
MW-1 5/13/02 Abandoned
100.00
MW-1R
93.20
10/15/03 4 0-7 7-22 22
1/3
Table 2
Groundwater Elevation Data
Former ExxonMobile Facility #99-GRE
Incident Number 20003
Monitor Well
I.D.
Date
Installed
Date Water
Level
Measured
Well Casing
Diameter
(inches)
Well Casing
Depth
(feet bgs)
Screened
Interval
(feet bgs)
Bottom of
Well
(feet bgs)
Relative
Top of
Casing
Elevation
(feet)
Depth to
Water from
Top of
Casing
(feet)
Free
Product
Thickness
(feet)
Relative
Groundwater
Elevation
(feet)
10/16/2003 9.11 0.00 89.92
1/13/2004 12.30 0.00 86.73
10/25/2007
8/14/2012 12.45 0.00 784.38
3/14/2013 12.88 0.00 783.95
9/20/2013 12.13 0.00 784.70
3/25/2014 12.21 0.00 784.62
9/24/2014 12.70 0.00 784.13
3/18/2015 12.97 0.00 783.86
9/10/2015 13.09 0.00 783.74
8/11/2016 11.96 0.00 784.87
9/15/2017 12.78 0.00 784.05
12/14/2018 11.39 0.00 785.44
3/29/2019 11.02 0.00 785.81
6/10/2019 11.31 0.00 785.52
9/18/2019 11.45 0.00 785.38
3/24/2020 11.67 0.00 785.16
11/11/2020 11.50 0.00 785.33
8/14/2012 16.99 0.00 783.08
3/14/2013 17.66 0.00 782.41
9/20/2013 17.15 0.00 782.92
3/25/2014 16.62 0.00 783.45
9/24/2014 17.15 0.00 782.92
3/18/2015 17.54 0.00 782.53
9/10/2015 17.81 0.00 782.26
8/11/2016 16.73 0.00 783.34
9/15/2017 17.67 0.00 782.40
12/14/2018 NG ----
3/29/2019 15.55 0.00 784.52
6/10/2019 15.96 0.00 784.11
9/18/2019 16.26 0.00 783.81
3/24/2020 16.12 0.00 783.95
11/11/2020 16.25 0.00 783.82
8/14/2012 16.35 0.00 785.60
3/14/2013 16.79 0.00 785.16
9/20/2013 15.56 0.00 786.39
3/25/2014 15.57 0.00 786.38
9/24/2014 16.41 0.00 785.54
3/18/2015 16.60 0.00 785.35
9/10/2015 16.76 0.00 785.19
8/11/2016 15.41 0.00 786.54
9/15/2017 16.60 0.00 785.35
12/14/2018 15.00 0.00 786.95
3/29/2019 14.19 0.00 787.76
6/10/2019 14.55 0.00 787.40
9/18/2019 14.86 0.00 787.09
3/24/2020 14.74 0.00 787.21
11/11/2020 15.05 0.00 786.90
3/25/2014 12.04 0.00 786.39
9/24/2014 12.98 0.00 785.45
3/18/2015 13.17 0.00 785.26
9/10/2015 13.14 0.00 785.29
8/11/2016 11.75 0.00 786.68
9/15/2017 12.95 0.00 785.48
12/14/2018 11.42 0.00 787.01
3/29/2019 10.62 0.00 787.81
6/10/2019 11.17 0.00 787.26
9/18/2019 11.45 0.00 786.98
3/24/2020 11.48 0.00 786.95
11/11/2020 11.62 0.00 786.81
8/11/2016 5.80 0.00 787.45
9/15/2017 6.75 0.00 786.50
12/14/2018 5.95 0.00 787.30
3/29/2019 9.20 0.00 784.05
6/10/2019 6.29 0.00 786.96
9/18/2019 7.10 0.00 786.15
3/24/2020 6.42 0.00 786.83
11/11/2020 6.45 0.00 786.80
0-10 10-20 20 798.43
800.07
MW-8 8/5/12 2 0-10 10-20 801.95
MW-5 10/15/03
MW-10 7/15/16 2 0-2
Abandoned
0-10 10-20
20
20
99.030-7 7-22 22
MW-6 8/5/12 2 0-10 10-20
2-12
MW-9 3/9/14 2
2
MW-7 8/5/12 2
20 796.83
12 793.25
2/3
Table 2
Groundwater Elevation Data
Former ExxonMobile Facility #99-GRE
Incident Number 20003
Monitor Well
I.D.
Date
Installed
Date Water
Level
Measured
Well Casing
Diameter
(inches)
Well Casing
Depth
(feet bgs)
Screened
Interval
(feet bgs)
Bottom of
Well
(feet bgs)
Relative
Top of
Casing
Elevation
(feet)
Depth to
Water from
Top of
Casing
(feet)
Free
Product
Thickness
(feet)
Relative
Groundwater
Elevation
(feet)
10/16/2003 11.05 0.00 85.98
1/13/2004 9.90 0.00 87.13
1/2/2006 12.15 0.00 84.88
10/3/2006 14.40 0.00 82.63
10/25/2007 15.67 0.00 81.36
10/13/2008 11.57 0.00 85.46
8/12/2009 10.91 0.00 86.12
8/9/2010 12.35 0.00 84.68
11/22/2010 14.15 0.00 82.88
2/26/2011 14.02 0.00 83.01
4/22/2011 13.50 0.00 83.53
5/23/2011 13.26 0.00 83.77
10/25/2011 13.22 0.00 83.81
3/15/2012 13.14 0.00 83.89
8/14/2012 13.75 0.00 784.74
3/14/2013 13.58 0.00 784.91
9/20/2013 12.46 0.00 786.03
3/25//14 12.35 0.00 786.14
9/24/2014 13.32 0.00 785.17
3/18/2015 13.35 0.00 785.14
9/10/2015 13.18 0.00 785.31
8/11/2016 12.62 0.00 785.87
9/15/2017 13.44 0.00 785.05
12/14/2018 11.77 0.00 786.72
3/29/2019 11.30 0.00 787.19
6/10/2019 11.21 0.00 787.28
9/18/2019 11.84 0.00 786.65
3/24/2020 11.75 0.00 786.74
11/11/2020 11.98 0.00 786.51
Notes:
bgs = below ground surface
*Monitoring well casing elevations surveyed by Arcadis G&M of North Carolina, Inc. on August 8, 2013 and by TWT June 2021
-- = Not Available
97.03
NG = Not Gauged
NS = Not Surveyed
2 0-38 38-43 43
798.49
DW-1 10/16/03
3/3
Attachment 1

June 7, 2021
ExxonMobil Corporation Attn: Ms. Jewel Cox 875 Popular Avenue, Suite 23, #353 Collierville, TN 38017
Re: Acknowledgement of Report Receipt
FISERV 101 N. Spring Street Greensboro, Guilford County
Incident Number: 20030 Risk Classification: Intermediate Ranking: I135D
Dear Ms. Cox:
This office acknowledges the receipt of your Fourth Quarter Groundwater Monitoring and Sampling Report
(2020) dated February 17, 2021 for the reference site. Your cooperation is appreciated. The report has been reviewed and maintained in the Guilford County Health Department and Human Services in Greensboro.
The review of the report indicates that no surface water samples have been collected from the creek located downgradient from the site. A sample needs to be collected from the creek for lab analysis to test the modeling result.
Benzene has increased in MW-9 since March 2019. MW-9 appears located side-gradient from the source area. But MW-9 and MW-10 have not been surveyed. Groundwater may also flow southwesterly toward
MW-10, and groundwater contamination may have migrated offsite from MW-9. Therefore, the elevation of these two wells need to be surveyed for constructing iso-potentiometric surface map. If you have any questions regarding this notice, please contact Gene Mao at the Guilford County Department of Health and Human Services, 400 W. Market Street, Suite 300, North Carolina 27401 and/or [phone]. Sincerely,
Carin Lee Kromm, L.G. Regional Supervisor Winston-Salem Regional Office
UST Section, Division of Waste Management, NCDEQ cc: Guilford County Department Health and Human Services
Attachment 2