table of contents · 2012-01-06 · site monitoring report september 2011 ... performed an initial...
TRANSCRIPT
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................................................................................................... 1
2.0 SAMPLING PROCEDURES AND RESULTS ............................................................................................... 2
2.1 GROUNDWATER CHARACTERISTICS .............................................................................................................. 2
2.2 GROUNDWATER SAMPLING AND ANALYTICAL RESULTS .............................................................................. 2
2.3 QUALITY ASSURANCE/QUALITY CONTROL .................................................................................................. 3
3.0 CONCLUSIONS AND RECOMMENDATIONS .............................................................................................. 4
FIGURES
Figure 1 Site Location Map
Figure 2 Site Plan
Figure 3 Groundwater Flow Direction Map
Figure 4 Contaminant Concentration Map
Figures 5-21 Time-Series Graphs
TABLES
Table 1 Groundwater Elevation Calculations
Table 2 Summary of Analytical Results
Table 3 Summary of Natural Attenuation Parameters
APPENDICES
Appendix A Laboratory Report
Appendix B Low Flow Sampling Field Forms
Fall 2011 Monitoring Report VTA1-0134D
Middlebury Mobil, VT DEC site #2001-2936 December 2011
Middlebury, Vermont Page 1
1.0 INTRODUCTION
This report summarizes the findings of the September 2011 semi-annual monitoring event conducted by
Environmental Compliance Services, Inc. (ECS) at the Middlebury Mobil, located on US Route 7, in
Middlebury, Vermont (Figures 1 and 2). This work was performed in accordance with the approved ECS
work plan dated March 23, 2011.
The site is an active Vermont Department of Environmental Conservation (VT DEC) hazardous site (Site
#2001-2936), and soil and groundwater contamination have been monitored since 2001. Petroleum
contamination was discovered in 2001 during excavation activities to rebuild or replace sumps on
gasoline underground storage tanks (USTs). Marin Environmental (now ECS) performed an initial site
investigation in 2001. Groundwater monitoring wells were installed and have been monitored since that
time, in addition to four pre-existing wells of unknown construction and date, which were designated EX-
1 through EX-4 by Marin and were assumed to be UST pad observation wells. A supplemental site
investigation was performed in 2003, and an additional site investigation was performed in 2004. A
surfactant flushing event was conducted in September 2007 in the UST grave. Filter socks containing
ORC©, an oxygen releasing compound, were installed in tank pad wells EX-1 through EX-4 from June
2009 to June 2010.
In September 2010, the three 8,000 gallon gasoline USTs, which were installed in 1982 were removed
and replaced, with environmental oversight by ECS and evidence of petroleum contamination was
observed in the excavation. Two 10,000 gallon gasoline USTs replaced the removed USTs in the same
tank grave. According to the site owner, underground piping to gasoline dispensers was also replaced
during recent construction. It was ECS’ opinion that the contamination encountered during UST
replacement was due to a historical release. This was based on the relatively low soil headspace
photoionization detector (PID) readings beneath the USTs. Black stained peastone and an odor
characteristic of weathered petroleum were noted by ECS. Groundwater within the excavation was de-
watered into a 21,000 gallon frac tank to accommodate the installation of the replacement gasoline USTs.
The water was subsequently discharged to the sanitary sewer in accordance with general permit #3-9016.
There was no visible sheen on groundwater, though some black residue was noted in the groundwater.
All excavation materials (i.e. primarily peastone) were returned to the UST excavation.
Fall 2011 Monitoring Report VTA1-0134D
Middlebury Mobil, VT DEC site #2001-2936 December 2011
Middlebury, Vermont Page 2
2.0 SAMPLING PROCEDURES AND RESULTS
2.1 GROUNDWATER CHARACTERISTICS
Depth to groundwater was measured on September 27, 2011 in eleven monitoring wells. Depth to
groundwater ranged from 2.58 feet (MW-4) to 4.66 feet (MW-1) below top-of-casing. Static water-table
elevations were computed for each monitoring well by subtracting the measured depth-to-water readings
from the surveyed top-of-casing elevations, which are relative to an arbitrary site datum of 100.00 feet.
Water-level measurements and elevation calculations are presented in Table 1. A groundwater-table
contour map was prepared using these data (Figure 3).
The groundwater table at the site has historically appeared to be relatively flat, although groundwater flow
directions and gradients fluctuate significantly. The soils in the site vicinity and surrounding area consist
of clayey soils of the Vergennes-Covington association (US Department of Agriculture, Soil Survey of
Addison County, Vermont, October 1971). The depth to this clay layer is generally on the order of three to
six feet bgs, based on information collected to date. The depth to groundwater in most of the monitoring
wells at the site is on the order of three to five feet below ground surface (bgs), corresponding with the
clay layer. Given the site hydrogeology, it is likely that groundwater flow in the site vicinity is influenced
by the heterogeneous subsurface conditions associated with the UST systems; sand and gravel fill
materials, and buried utilities.
2.2 GROUNDWATER SAMPLING AND ANALYTICAL RESULTS
On September 27, 2011, groundwater samples were collected for laboratory analysis from seven select
monitoring wells (MW-1, MW-2, MW-4, MW-5, MW-7, MW-8, and MW-11). EX-1, EX-2, EX-3, and
EX-4 were destroyed during UST replacement activities in September 2010. MW-3, MW-9, MW-12, and
MW-13 were removed from the groundwater sampling plan. MW-10 was destroyed. MW-6 was
abandoned in accordance with water supply rules on September 27, 2011.
The monitoring wells were purged and sampled using low-flow sampling techniques through a peristaltic
pump. Field indicator parameters including ORP, DO, temperature, specific conductance, and pH were
obtained during well purging for all wells via a portable multi-parameter water quality meter and flow
cell. In accordance with EPA recommended practices, samples for turbidity evaluation were collected
from the discharge end of the flow cell and measured with a turbidity meter. After stabilization of field
indicator parameters, samples were collected from all wells for laboratory analysis of petroleum-related
VOCs on the Vermont 8021B list via EPA Method 8260. Samples were transported under chain of
custody in an ice-filled cooler to Endyne Laboratories, Inc. of Williston, Vermont. All field procedures
were conducted in accordance with ECS standard protocols. A summary of analytical results is presented
in Table 2. Table 3 summarizes stabilized field parameters. A contaminant distribution map is presented
as Figure 4. Time series graphs are included as Figures 5 though 21. The laboratory report is included as
Appendix A. Low flow field sheets are included as Appendix B. Literature indicates that aerobic
biodegradation occurs at a reasonable rate at dissolved oxygen concentrations above 2.0 mg/l.
The Vermont Groundwater Enforcement Standards (VGES) for one or more petroleum-related volatile
organic compounds (VOCs) were exceeded in groundwater samples collected from two of the seven
sampled monitoring wells. Methyl tert-butyl ether (MTBE) exceeded the VGES in the samples collected
from MW-2 and MW-5. Benzene also exceeded the VGES in samples collected from MW-2. The highest
total benzene, toluene, ethylbenzene, and xylenes (BTEX) concentration was 88.2 micrograms per liter
Winter 2010 Monitoring Report VTA1-0134D
Middlebury Mobil, VT DEC site #2001-2936 December 2011
Middlebury, Vermont Page 3
(µg/L) in MW-2. No free phase product was detected at the site. Historically, the highest contaminant
concentrations have been detected in the EX-series wells in the vicinity of the current and former gasoline
USTs. These wells were destroyed in September 2010 during UST replacement activities.
2.3 QUALITY ASSURANCE/QUALITY CONTROL
Quality assurance/quality control (QA/QC) samples included a trip blank and a blind duplicate sample
collected from MW-2. An equipment blank was also collected by running deionized water through pump
tubing and collecting it into 40 mL vials preserved with hydrochloric acid. The relative percent
difference (RPD) for the duplicate sample was within 30% with the exception of MTBE detected at 35%.
Fall 2011 Monitoring Report VTA1-0134D
Middlebury Mobil, VT DEC site #2001-2936 December 2011
Middlebury, Vermont Page 4
3.0 CONCLUSIONS AND RECOMMENDATIONS
The majority of the dissolved-phase groundwater VOC plume appears to be located in the vicinity of the
current gasoline USTs at the site. The former gasoline additive MTBE was detected in five of the wells
sampled at the site. Contaminant concentrations have decreased significantly site-wide since sampling
began in 2001, with the exception of the MTBE concentration in MW-5, which has remained relatively
stable in the range of 400 to 700 µg/L. MW-5 has decreased to 350 µg/L during this sampling period. The
general site-wide decrease is likely partially attributable to remediation, which included surfactant
flushing and oxygen release compound. During September 2010 UST replacement activities,
contaminated groundwater was removed from the excavation, and clean backfill material was used in
addition to excavated materials in the installation of the new USTs, which also removed contaminant
mass in the source area.
Although significant improvements have been realized at the site, recent DO concentrations in wells
adjacent to the source area indicate the presence of an anaerobic groundwater signature. This is also
corroborated by negative ORP and elevated specific conductance in some instances. These conditions
indicate that biodegradation is active, but degradation rates in plume “cores” are much slower due to
depleted oxygen. However, the presence of “fresh” groundwater outside the source area tends to stabilize
the plume due to increased biodegradation rates (available oxygen) along the perimeter.
EX-series wells EX-1, EX-2, EX-3, and EX-4 were destroyed during September 2010 UST replacement.
Three 8,000 gallon gasoline USTs were replaced with two 10,000 gallon gasoline USTs in the same UST
grave. Underground piping to gasoline dispensers were also replaced during recent construction.
Based on exceedances of VGES, ECS recommends the following:
1. Groundwater sampling should continue on an annual basis, with the next event scheduled for fall
2012. All seven monitoring wells on the current sampling program should be sampled for
petroleum hydrocarbons utilizing the low flow purging methodology on the Vermont 8021B list
of target VOCs.
FIGURES
.QUADRANGLE LOCATION
DRAWN BY: DH 2/28/2005 SCALE: 1in = 2000ftAPPROVED BY: LW FILE: A!0134sloc.mxd
Middlebury, VermontMiddlebury MobilSITE:
FIGURE 1. SITE LOCATION MAPTITLE:
MIDDLEBURY Quadrangle (Last Revised: 1983)Source: USGS Topographic Map
Site Lat/Long NAD83: 44.0029, -73.1561
2,000 0 2,000 4,000Feet
Middlebury Mobil
FIGURE 5. EX-1
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
12/10/01 NS NS NS NS NS NS NS NS NS 95.21
05/20/02 42,830 78,500 9,840 19,500 1,690 11,800 1,405 177 122,912 95.65
01/03/03 24,560 17,000 1,870 9,380 1,510 11,800 2,207 225 43,992 95.78
03/18/04 7,909 12,900 1,140 262 1,140 5,367 1,420 245 22,474 95.74
09/30/04 1,910 4,740 445 60.3 592 813 841 135 7,626 95.15
07/11/05 3,113 4,760 640 64.4 829 1,580 1,120 229 9,222 95.79
11/08/05 2,806 4,320 580 78.6 887 1,260 1,450 327 8,903 95.89
01/24/07 2,105 200 178 56.5 670 1,200 1,834.3 243 4,381.8 95.61
10/30/07 932 100 90.4 ND<50 325 517 1,330 183 2,545.4 95.48
06/24/08 2,148 273 613 796 280 459 1,060 111 3,592 95.91
11/03/08 774 216 214 ND<50.0 230 330 1,180 ND<100 2,170 95.72
06/09/09 575 101 173 ND<50.0 133 269 766 ND<100 1,442 95.79
12/28/09 654 233 191 72.5 141 249 682 40.2 1,609 95.62
06/17/10 830 113 309 218 100 203 535 31.7 1,510 95.54
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
NS - Not Sampled.
VGES - Vermont Groundwater Enforcement Standards
All samples collected by ECS and analyzed by Endyne, Inc.
Shaded areas denote VGES exceedance.
Top of casing elevation for EX-1 is 98.34 feet.
Well Destroyed
92.00
93.00
94.00
95.00
96.00
97.00
0
20,000
40,000
60,000
80,000
100,000
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 6. EX-2
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
12/10/01 NS NS NS NS NS NS NS NS NS 95.30
05/20/02 29,320 15,000 2,470 11,000 1,650 14,200 2,792 337 47,449 95.80
01/03/03 20,670 12,200 1,490 5,930 1,450 11,800 2,821 270 35,961 95.79
03/18/04 4,253 7,350 641 296 694 2,622 1,499 227 13,329 95.85
09/30/04 3,507 6,880 605 75.4 677 2,150 1,083 189 11,659 95.25
07/11/05 681 1,550 198 ND<50.0 277 206 542 73.6 2,847 95.92
11/08/05 1,528 1,340 200 ND<50.0 559 769 1,090 159.0 4,117 95.90
01/24/07 1,074.3 550 132 23.3 407 512 850 114 2,588 95.55
10/30/07 ND 41.6 ND<20 ND<20 ND<20 ND<40 68.8 ND<40 110 95.45
06/24/08 787 197 258 179 119 231 456.2 ND<40.0 1,440.2 95.88
11/03/08 736 208 166 172 133 265 499.0 ND<40.0 1,443.0 95.68
06/09/09 493 221 131 83.7 91.9 186 318 ND<40.0 1,031.6 95.77
12/28/09 302 248 98.6 62.2 42.6 98.6 197 ND<40.0 747 95.63
06/17/10 263 125 81.5 81.9 31.5 67.8 89 ND<10.0 477 95.52
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
NS - Not Sampled.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Shaded areas denote VGES exceedance.
Top of casing elevation for EX-2 is 98.45 feet.
Well Destroyed
92.00
93.00
94.00
95.00
96.00
97.00
0
5,000
10,000
15,000
20,000
25,000
30,000
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 7. EX-3
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
12/10/01 343.2 192 42.3 193 16.7 91.2 16.3 2.5 554 95.38
05/20/02 16,980 18,900 3,280 4,480 1,450 7,770 2,294 289 38,463 95.84
01/03/03 13,320 11,100 1,400 3,520 1,130 7,270 2,101 210 26,731 95.82
03/18/04 3,613 4,880 499 429 598 2,087 1,197.4 191 9,881 95.90
09/30/04 5,096 8,100 708 44.0 884 3,460 1,336 237 14,769 96.28
07/11/05 772 1,910 262 21.6 350 138 733.2 108 3,523 96.01
11/08/05 2,548 1,130 193 59.5 815 1,480 1,484.3 240 5,402 95.90
01/24/07 804 626 146 ND<20 374 284 576 86.9 2,093 95.58
10/30/07 282 64.7 32 ND<20 86.6 163 432.8 ND<40 779 95.53
06/24/08 875 199 215 119 177 364 490.7 41.6 1,606 95.95
11/03/08 781 181 169 168 148 296 556.2 ND<40.0 1,518 95.73
06/09/09 488 130 117 44.7 104 222 329 ND<40.0 947 95.75
12/28/09 443 163 122 82.6 88.8 150 353 ND<40.0 959 95.65
06/17/10 361 101 82.7 78.9 52.6 147 126 ND<10.0 588 95.58
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Shaded areas denote VGES exceedance.
Top of casing elevation for EX-3 is 98.93 feet.
Well Destroyed
92.00
93.00
94.00
95.00
96.00
97.00
0
4,000
8,000
12,000
16,000
20,000
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 8. EX-4
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
12/10/01 NS NS NS NS NS NS NS NS NS 95.42
05/20/02 18,930 8,630 1,090 5,170 1,570 11,100 2,533 314 30,407 95.90
01/03/03 15,900 13,600 1,340 3,190 1,480 9,890 2,650 360 32,510 95.80
03/18/04 8,456 12,500 1,290 213 1,280 5,673 1,758 323 23,037 95.90
09/30/04 1,608 5,590 544 ND<50.0 550 514 1,023 113 8,334 96.21
07/11/05 2,981 4,470 582 76.7 812 1,510 1,230 241 8,922 95.97
11/08/05 5,695 1,130 238 190 967 4,300 2,683 328 9,836 95.90
01/24/07 2,642 809 233 57.4 932 1,420 1,690 271 5,412 95.61
10/30/07 1,602 144 140 75.8 503 883 1,447 218 3,411 95.51
06/24/08 1,362 233 216 183 384 579 1,210 149 2,954 95.90
11/03/08 835 226 172 ND<50.0 280 383 1,190 107 2,358 95.73
06/09/09 767 134 160 ND<50.0 230 377 966 ND<100 1,867 95.63
12/28/09 647 199 159 60.0 187 241 994 ND<100 1,840 95.62
06/17/10 501 135 133 88.6 126 153 568 28.4 1,232 95.52
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
NS - Not Sampled.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Shaded areas denote VGES exceedance.
Top of casing elevation for EX-4 is 98.95 feet.
Well Destroyed
94.00
94.50
95.00
95.50
96.00
96.50
0
4,000
8,000
12,000
16,000
20,000
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 9. MW-1
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
12/10/01 1.1 4.6 ND<1.0 ND<1.0 ND<1.0 1.1 ND<2.0 3.0 9 95.60
05/20/02 1.0 5.7 1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 7 96.03
01/03/03 ND 5 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 5 95.58
03/18/04 ND ND<1.0 ND<1.0 ND<2.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 ND 96.14
09/29/04 ND ND<1.0 ND<1.0 ND<2.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 ND 95.13
07/11/05 ND ND<1.0 ND<1.0 ND<2.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 ND 95.11
11/08/05 ND ND<1.0 ND<1.0 ND<2.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 ND 95.59
01/24/07 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND 95.12
10/30/07 ND 3.5 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 3.5 95.48
06/24/08 ND ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 95.82
11/03/08 ND ND<2.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 94.85
12/08/10 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<1.0 ND<2.0 ND 95.80
09/27/11 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<1.0 ND<2.0 ND 95.34
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Top of casing elevation for MW-1 is 100 feet.
MW-1 was removed from the sampling plan in 2009 and re-instated in 2010.
94.00
94.50
95.00
95.50
96.00
96.50
0
2
4
6
8
10
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 10. MW-2
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
12/10/01 39,370 8,300 1,550 18,300 1,220 18,300 3,078 314 51,062 95.33
05/20/02 25,097 5,420 1,100 8,370 927 14,700 4,220 549 35,286 95.83
01/03/03 9,625 3,800 512 1,930 453 6,730 1,350 89 14,864 94.72
03/18/04 2,896 5,060 86.8 159 130 2,520 715 51.8 8,723 95.90
09/30/04 115 65.1 4.6 2.9 14.7 92.6 51.3 5.5 237 95.71
07/11/05 2,098 670 115 64.8 318 1,600 918 131 3,817 95.97
11/08/05 2,842 1,210 132 77.7 432 2,200 1,517 165 5,734 95.90
01/24/07 1,327 222 64.5 ND<50 332 930 1,313 128 2,990 95.61
10/30/07 174 241 ND<50.0 ND<50.0 69 105 209 ND<100 624 95.52
06/24/08 233 390 52.7 ND<1.0 79 102 206 24.1 854 95.91
11/03/08 102 178 17.9 ND<10.0 36.6 47.4 139 ND<20.0 419 95.67
06/09/09 379 470 143 24.0 122 89.7 420 ND<20.0 1,269 95.72
12/28/09 62 122 15.7 ND<5.0 28.1 18.4 154 ND<10.0 338 95.61
06/17/10 279.6 105 52.5 20.7 79.4 127 540 25.1 949 95.52
12/08/10 28.8 77.8 12.4 ND<1.0 14.5 1.9 41.9 ND<2.0 149 95.88
09/27/11 88.2 146.0 31.6 ND<1.0 47.7 8.9 30.1 5.3 270 95.73
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Shaded areas denote VGES exceedance.
Top of casing elevation for MW-2 is 99.52 feet.
92.00
93.00
94.00
95.00
96.00
97.00
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 11. MW-3
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
12/10/01 ND 2.1 ND<1.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<1.0 2 95.58
05/20/02 ND 30.9 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 31 95.95
01/03/03 ND 34.2 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 34 95.91
03/18/04 ND 9.2 ND<1.0 1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 10 96.08
09/30/04 ND 25.9 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 26 95.78
07/11/05 ND 6.9 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 7 96.01
11/08/05 ND 16.8 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 17 95.95
01/24/07 ND 42.5 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 43 95.65
10/30/07 ND 2.9 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 2.9 95.84
06/24/08 ND ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 96.02
11/03/08 ND 2.5 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 2.5 96.06
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Shaded areas denote VGES exceedance.
Top of casing elevation for MW-3 is 100.04 feet.
MW-3 was removed from the sampling plan in 2009.
85.00
87.00
89.00
91.00
93.00
95.00
97.00
0
10
20
30
40
50
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 12. MW-4
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
12/10/01 ND 25.0 ND<1.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 1.3 26 91.32
05/20/02 1.4 3.5 1.4 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 5 96.43
01/03/03 ND 10.3 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 10 96.70
03/18/04 1.5 3.0 ND<1.0 1.5 ND<1.0 ND<2.0 ND<2.0 ND<1.0 5 96.98
09/30/04 1.1 3.2 1.1 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 5 96.00
07/11/05 1 3.1 1 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 5 96.84
11/08/05 1 2.3 1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 5 96.49
01/24/07 ND 6.1 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 6.1 96.11
10/30/07 ND 6.3 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 6.3 96.57
06/24/08 ND 4.7 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 4.7 96.85
11/03/08 ND 5.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 5.0 96.35
12/08/10 ND 4.9 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 4.9 96.47
09/27/11 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND 96.29
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Top of casing elevation for MW-4 is 98.87 feet.
MW-4 was removed from the sampling plan in 2009 and re-instated in 2010.
78.00
82.00
86.00
90.00
94.00
98.00
0
10
20
30
40
50
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 13. MW-5
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
01/21/02 ND 420 ND<5.0 ND<5.0 ND<5.0 ND<5.0 ND<10.0 ND<5.0 420 92.61
05/20/02 50.1 450 50.1 ND<2.0 ND<2.0 ND<4.0 ND<2.0 ND<1.0 500 96.27
01/03/03 ND 280 ND<2.0 ND<2.0 ND<2.0 ND<4.0 ND<4.0 ND<2.0 280 95.37
03/18/04 2.0 609 ND<1.0 2.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 611 94.83
09/30/04 ND 712 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 712 95.69
07/11/05 55.6 612 55.6 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 668 95.71
11/08/05 ND 503 ND<5.0 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<5.0 503 95.66
01/24/07 46.2 505 46.2 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<10.0 551 95.40
10/30/07 65.6 544 65.6 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<10.0 610 95.13
06/24/08 54.9 551 54.9 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<10.0 606 94.71
11/03/08 ND 550 ND<5.0 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<10.0 550 94.22
06/09/09 ND 664 ND<5.0 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<10.0 664 95.97
12/28/09 ND 660 ND<5.0 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<10.0 660 95.64
06/17/10 ND 766 ND<5.0 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<10.0 766 95.82
12/08/10 ND 532 ND<5.0 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<10.0 532 95.72
09/27/11 ND 387 ND<5.0 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<10.0 387 95.87
VGES --- 40 5 1,000 700 10,000 350 20 ---
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Shaded areas denote VGES exceedance.
Top of casing elevation for MW-5 is 99.62 feet.
87.00
89.00
91.00
93.00
95.00
97.00
0
200
400
600
800
1,000
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 14. MW-6
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
01/03/03 ND ND<1.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 ND 95.22
03/18/04 ND ND<1.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 ND 95.29
09/29/04 ND ND<1.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 ND 95.00
07/11/05 ND ND<1.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 ND 95.32
11/08/05 ND ND<1.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 ND 95.14
01/24/07 2.1 ND<2.0 ND<1.0 ND<1.0 ND<1.0 2.1 2.2 6.2 10.5 94.31
10/30/07 10.2 ND<10.0 ND<5.0 ND<5.0 ND<5.0 10.2 5.4 ND<10.0 15.6 94.10
06/24/08 ND ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 95.25
11/03/08 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND 94.59
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Top of casing elevation for MW-6 is 98.45 feet.
NM-Not Measured
MW-6 was removed from the sampling plan in 2009.
90.00
91.00
92.00
93.00
94.00
95.00
96.00
0
4
8
12
16
20
09/01/02 01/14/04 05/28/05 10/10/06 02/22/08 07/06/09
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 15. MW-7
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
01/03/03 ND 21.8 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 22 95.70
03/18/04 14 157 7.5 1.5 ND<1.0 5.3 ND<2.0 ND<1.0 171 95.71
09/30/04 ND 94 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 94 95.41
07/11/05 ND 65.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 65 95.94
11/08/05 ND 18.9 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 19 95.62
01/24/07 1.1 52.2 1.1 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 53.3 95.48
10/30/07 ND 19.2 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 19.2 95.11
06/24/08 ND ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 95.62
11/03/08 ND 2.2 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 2.2 95.61
06/09/09 ND ND<2.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 95.50
12/28/09 ND 9.7 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 9.7 95.46
06/17/10 ND 7.6 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 7.6 95.06
12/08/10 7.5 ND<2.0 ND<1.0 1.7 ND<1.0 5.8 1.8 2.5 11.8 95.62
09/27/11 ND 7.7 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 7.7 95.45
VGES --- 40 5 1,000 700 10,000 350 20 ---
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Shaded areas denote VGES exceedance.
Top of casing elevation for MW-7 is 98.51 feet.
92.00
93.00
94.00
95.00
96.00
97.00
98.00
0
100
200
300
400
500
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 16. MW-8
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
01/03/03 3,920 2,190 107 734 58.8 3,020 539 30 6,679 95.70
03/18/04 3,606 1,700 35.4 799 21.8 2,750 233.4 14.2 5,554 95.85
09/30/04 3,077 493 46.8 335 94.8 2,600 618 74.2 4,262 95.67
07/11/05 1,194 79.8 ND<20.0 50.2 23.4 1,120 244.4 48.7 1,567 95.93
11/08/05 2,051 118 71.0 282 208 1,490 473 165 2,807 95.86
01/24/07 370 103 24.8 ND<20 47.1 298 276.9 43.9 794 95.58
10/30/07 105 518 83.6 ND<20.0 20.9 ND<40.0 47.2 ND<40.0 670 95.46
06/24/08 11.9 6.8 2.7 ND<1.0 ND<2.0 9.2 1.2 ND<2.0 19.9 95.87
11/03/08 8.4 8.6 1.3 ND<1.0 ND<2.0 7.1 ND<2.0 ND<2.0 17.0 95.66
06/09/09 148 35.5 10.5 ND<2.0 ND<2.0 137 84.7 6.1 274 95.70
12/28/09 19 49.3 10.3 ND<1.0 1.4 7.3 4.1 ND<2.0 72.4 95.46
06/17/10 149.2 41.7 64.8 37.1 13.6 33.7 50.8 2.5 244.2 95.50
12/08/10 12.9 3.3 ND<1.0 ND<1.0 ND<1.0 12.9 5.4 ND<2.0 21.6 95.90
09/27/11 10.2 7.6 ND<1.0 ND<1.0 ND<1.0 10.2 5.8 ND<2.0 23.6 95.68
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Shaded areas denote VGES exceedance.
Top of casing elevation for MW-8 is 99.50 feet.
94.00
94.40
94.80
95.20
95.60
96.00
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
Gro
un
d W
ate
r E
lev
ati
on
(ft
)
VO
C C
on
ce
ntr
ati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 17. MW-9
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
01/03/03 ND 1.4 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 1.4 95.68
03/18/04 1.0 5.6 ND<1.0 1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 6.6 95.79
09/30/04 ND 3.3 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 3.3 95.60
07/11/05 ND 12.8 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 12.8 95.85
11/08/05 ND 2.9 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 2.9 95.87
01/24/07 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND 95.48
10/31/07 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND 92.08
06/24/08 ND ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 95.81
11/03/08 ND ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 95.58
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Top of casing elevation for MW-9 is 99.98 feet.
MW-9 was removed from the sampling plan in 2009.
87.00
89.00
91.00
93.00
95.00
97.00
0
10
20
30
40
50
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 18. MW-10
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
03/18/04 ND ND<20 ND<10 ND<10 ND<10 ND<20 ND<20 ND<10 ND 95.60
10/07/04 ND ND<1.0 ND<1.0 ND<10 ND<10 ND<2.0 ND<20 ND<10 ND 90.17
07/11/05 ND ND<1.0 ND<1.0 ND<10 ND<10 ND<2.0 ND<20 ND<10 ND 90.62
11/08/05 ND ND<1.0 ND<1.0 ND<10 ND<10 ND<2.0 ND<20 ND<10 ND 90.68
01/24/07 NS NS NS NS NS NS NS NS NS NS
10/30/07 NS NS NS NS NS NS NS NS NS NS
06/24/08
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Top of casing elevation for MW-10 is 99.07 feet.
NS - Not Sampled (could not be located)
Well Destroyed
86.00
88.00
90.00
92.00
94.00
96.00
0
2
4
6
8
10
01/03/03 07/02/03 12/29/03 06/26/04 12/24/04 06/22/05 12/19/05 06/17/06
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 19. MW-11
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
11/08/05 12 37.1 1.8 ND<1.0 3.4 6.6 5.0 1.4 55 95.82
01/24/07 36.2 43.3 8.9 ND<1.0 15.3 12.0 20.4 ND<2.0 100 95.50
10/30/07 ND 8.4 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 8 95.40
06/24/08 12.8 32.9 8.8 ND<1.0 1.5 2.5 2.6 ND<2.0 48 95.74
11/03/08 ND 17.5 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 18 95.57
06/09/09 ND 5.8 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 6 95.63
12/28/09 9.1 29.8 3.8 ND<1.0 5.3 ND<2.0 1.0 ND<2.0 40 95.44
06/17/10 89.2 109 65.7 6.3 8.2 9.0 5.8 ND/<2.0 204 95.37
12/08/10 98.0 6.4 22.9 35.1 1.7 38.3 12.7 4.9 122 95.78
09/27/11 5.0 12.2 2.6 ND<1.0 2.4 ND<2.0 ND<2.0 ND<2.0 17 95.61
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Shaded areas denote VGES exceedance.
Top of casing elevation for MW-10 is 99.07 feet.
86
88
90
92
94
96
0
50
100
150
200
250
300
Gro
un
d W
ate
r E
lev
ati
on
(ft
)
VO
C C
on
cen
trati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 20. MW-12
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
11/08/05 ND 2.5 ND<1.0 ND<2.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 3 95.84
01/24/07 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND 95.59
10/30/07 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND 95.57
06/24/08 ND ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 95.86
11/03/08 ND ND<2.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 95.66
12/08/10 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<1.0 ND<2.0 ND 95.89
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Top of casing elevation for MW-10 is 99.07 feet.
MW-12 was removed from the sampling plan in 2009 and re-instated for 2010.
86.00
88.00
90.00
92.00
94.00
96.00
98.00
0
2
4
6
8
10
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
ce
ntr
ati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
FIGURE 21 MW-13
VOC Concentrations
Middlebury Mobil
Middlebury, Vermont
DateTotal
BTEXMTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
Benzenes
Naph-
thalene
Total
VOCs
Ground-
Water
Elevation
11/08/05 ND ND<1.0 ND<1.0 ND<2.0 ND<1.0 ND<2.0 ND<2.0 ND<1.0 ND 95.89
01/24/07 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND 95.40
10/30/07 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND 95.74
06/24/08 ND ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND<2.0 ND 95.94
11/03/08 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND 95.76
VGES --- 40 5 1,000 700 10,000 350 20 --- ----
Notes: Results given in micrograms per liter (µg/L)
ND- None detected at indicated detection limit.
All samples collected by ECS and analyzed by Endyne, Inc.
VGES - Vermont Groundwater Enforcement Standards
Top of casing elevation for MW-10 is 99.07 feet.
MW-13 was removed from the sampling plan in 2009.
86.00
88.00
90.00
92.00
94.00
96.00
0
2
4
6
8
10
Gro
un
d W
ate
r E
levati
on
(ft
)
VO
C C
on
ce
ntr
ati
on
s (
µg
/L)
Date
Benzene Total BTEX MTBE Ground-Water Elevation
ECS Time.Series-VTA10134btx.xlsx
TABLES
TABLE 1
GROUNDWATER ELEVATION DATA
Middlebury Mobil
Middlebury, Vermont
Monitoring Date: September 27, 2011
Well I.D.
Depth to
Water
Ground
Water
Elevation
(ft, TOC) (feet)
MW-1 100.00 4.66 95.34
MW-2 99.52 3.79 95.73
MW-3 100.04 4.28 95.76
MW-4 98.87 2.58 96.29
MW-5 99.62 3.75 95.87
MW-7 98.51 3.06 95.45
MW-8 99.50 3.82 95.68
MW-9 99.98 4.33 95.65
MW-11 99.37 3.76 95.61
MW-12 99.79 4.14 95.65
MW-13 100.07 4.27 95.80
EX-1 98.34 NM NM
EX-2 98.45 NM NM
EX-3 98.93 NM NM
EX-4 98.95 NM NM
Notes:
All values reported in feet relative to an arbitrary 100' datum.
ft = Feet
TOC = Top of Casing
NM = Not Measured
Shaded wells were destroyed during new concrete pad installation.
Top of
Casing
Elevation
ECS VTA1-0134D
TABLE 2
SUMMARY OF GROUNDWATER ANALYTICAL RESULTS
Middlebury Mobil
Middlebury, Vermont
Monitoring Date:
September 27, 2011
Sample
LocationTotal BTEX MTBE Benzene Toluene
Ethyl
benzeneXylenes
Trimethyl
benzenes
Naph-
thalene
Total
VOCs
MW-1 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<1.0 ND<2.0 ND
MW-2 88.2 146 31.6 ND<1.0 47.7 8.9 30.1 5.3 270
MW-4 ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND
MW-5 ND 387 ND<5.0 ND<5.0 ND<5.0 ND<10.0 ND<10.0 ND<10.0 387
MW-7 ND 7.7 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 7.7
MW-8 10.2 7.6 ND<1.0 ND<1.0 ND<1.0 10.2 5.8 ND<2.0 23.6
MW-11 5.0 12.2 2.6 ND<1.0 2.4 ND<2.0 ND<2.0 ND<2.0 17
VGES -- 40 5.0 1,000 700 10,000 350 20 --
MW-2 88.2 146.0 31.6 ND<1.0 47.7 8.9 30.1 5.3 270
Duplicate MW-2 111.5 209 40.7 ND<5.0 59.3 11.5 35.1 ND<10.0 356
% Difference -- 35 25 -- 22 25 15 -- --
Equipment Blank ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND
Trip blank ND ND<2.0 ND<1.0 ND<1.0 ND<1.0 ND<2.0 ND<2.0 ND<2.0 ND
Notes:
Monitoring wells analyzed for VOCs using EPA Method 8021B
Results given in micrograms per liter (µg/L).
ND - None detected at indicated detection limit.
VGES - Vermont Groundwater Enforcement Standards.
Shaded concentrations exceed VGES.
MW-10 has been destroyed
EX-1, EX-2, EX-3, and EX-4 were destroyed during new concrete pad installation.
MTBE - methyl tert-butyl ether
BTEX - total benzene, toluene, ethylbenzene, and xylenes
VOCs - volatile organic compounds
Quality Assurance/Quality Control Samples by EPA Method 8021B
ECS Table.2-VTA10134VOC.xlsx
TABLE 3
SUMMARY OF NATURAL ATTENUATION PARAMETERS
Middlebury Mobil
Middlebury, Vermont
Monitoring Date: September 27, 2011
Well I.D. Temp. Specific
Conductance pH ORP / Eh DO Turbidity Comments
(oC) (uS/cm) (mV) (mg/L) (NTU)
MW-1 20.44 922 7.16 86.8 10.92 0.43 Intake reached
MW-2 22.61 4,050 7.02 -156.0 0.41 0.34 Parameters stabilized
MW-4 22.27 5,473 7.10 7.3 1.64 0.00 Parameters stabilized
MW-5 19.19 8,337 6.52 107.2 5.10 0.00 Parameters stabilized
MW-7 25.20 4,039 7.07 -41.3 0.35 1.53 Parameters stabilized
MW-8 20.39 1,268 7.07 -99.8 0.40 2.34 Parameters stabilized
MW-11 21.49 2,196 7.20 -102.4 0.47 0.48 Parameters stabilized
Notes:
mg/L - milligrams per liter
uS/cm - microSiemens per centimeter
mV- milivolts
NTU - nephelometric turbidity units
MW-10 has been destroyed.
EX-1, EX-2, EX-3, and EX-4 were destroyed during new concrete pad installation.
ECS VTA1-0134D
APPENDIX A LABORATORY ANALYTICAL REPORTS
Laboratory Report
Middlebury MobilPROJECT:
DATE RECEIVED:WORK ORDER:
DATE REPORTED:
100488ECS-Waterbury1 Elm StreetSuite 3Waterbury, VT 05676
SAMPLER:October 03, 2011
1109-14189
JG/SH
September 27, 2011
Reviewed by:
Harry B. Locker, Ph.D.Laboratory Director
Enclosed please find the results of the analyses performed for the samples referenced on the attached chain of custody. All required method quality control elements including instrument calibration were performed in accordance with method requirements and determined to be acceptable unless otherwise noted.
The column labeled Lab/Tech in the accompanying report denotes the laboratory facility where the testing was performed and the technician who conducted the assay. A "W" designates the Williston, VT lab under NELAC certification ELAP 11263; "R" designates the Lebanon, NH facility under certification NH 2037 and “N” the Plattsburgh, NY lab under certification ELAP 11892. “Sub” indicates the testing was performed by a subcontracted laboratory. The accreditation status of the subcontracted lab is referenced in the corresponding NELAC and Qual fields.
The NELAC column also denotes the accreditation status of each laboratory for each reported parameter. “A” indicates the referenced laboratory is NELAC accredited for the parameter reported. “N” indicates the laboratory is not accredited. “U” indicates that NELAC does not offer accreditation for that parameter in that specific matrix. Test results denoted with an “A” meet all National Environmental Laboratory Accreditation Program requirements except where denoted by pertinent data qualifiers. Test results are representative of the samples as they were received at the laboratory
Endyne, Inc. warrants, to the best of its knowledge and belief, the accuracy of the analytical
test results contained in this report, but makes no other warranty, expressed or implied, especially no warranties of merchantability or fitness for a particular purpose.
160 James Brown Dr., Williston, VT 05495Ph 802-879-4333 Fax 802-879-7103 ELAP 11263
www.endynelabs.com
NH203756 Etna Road, Lebanon, NH 03766 Ph 603-678-4891 Fax 603-678-4893
Laboratory Report
ECS-Waterbury
Page 2 of 3CLIENT:PROJECT: Middlebury Mobil
WORK ORDER:DATE RECEIVED:
1109-1418909/27/2011
10/3/2011REPORT DATE:
001 Date Sampled: 9/27/11Site: Trip Blank 9/28/11 RBFWAnalysis Date:QualNelacUnitResultParameterQualNelacUnitResultParameter
TEST METHOD: EPA 8021B
< 2.0 NMethyl-t-butyl ether (MTBE) ug/L < 1.0 NBenzene ug/L< 1.0 NToluene ug/L < 1.0 NEthylbenzene ug/L< 2.0 NXylenes, Total ug/L < 1.0 N1,3,5-Trimethylbenzene ug/L< 1.0 N1,2,4-Trimethylbenzene ug/L < 2.0 NNaphthalene ug/L104 NSurr. 1 (Bromobenzene) % 0 NUnidentified Peaks
002 Date Sampled: 9/27/11Site: Duplicate 9/29/11 RBFWAnalysis Date:QualNelacUnitResultParameterQualNelacUnitResultParameter
TEST METHOD: EPA 8021B
209 NMethyl-t-butyl ether (MTBE) ug/L 40.7 NBenzene ug/L< 5.0 NToluene ug/L 59.3 NEthylbenzene ug/L11.5 NXylenes, Total ug/L < 5.0 N1,3,5-Trimethylbenzene ug/L35.1 N1,2,4-Trimethylbenzene ug/L < 10.0 NNaphthalene ug/L91 NSurr. 1 (Bromobenzene) % > 10 NUnidentified Peaks
003 Date Sampled: 9/27/11Site: Equipment Blank 9/28/11 RBFWAnalysis Date:10:00QualNelacUnitResultParameterQualNelacUnitResultParameter
TEST METHOD: EPA 8021B
< 2.0 NMethyl-t-butyl ether (MTBE) ug/L < 1.0 NBenzene ug/L< 1.0 NToluene ug/L < 1.0 NEthylbenzene ug/L< 2.0 NXylenes, Total ug/L < 1.0 N1,3,5-Trimethylbenzene ug/L< 1.0 N1,2,4-Trimethylbenzene ug/L < 2.0 NNaphthalene ug/L
99 NSurr. 1 (Bromobenzene) % 0 NUnidentified Peaks
004 Date Sampled: 9/27/11Site: MW-7 9/29/11 RBFWAnalysis Date:11:24QualNelacUnitResultParameterQualNelacUnitResultParameter
TEST METHOD: EPA 8021B
7.7 NMethyl-t-butyl ether (MTBE) ug/L < 1.0 NBenzene ug/L< 1.0 NToluene ug/L < 1.0 NEthylbenzene ug/L< 2.0 NXylenes, Total ug/L < 1.0 N1,3,5-Trimethylbenzene ug/L< 1.0 N1,2,4-Trimethylbenzene ug/L < 2.0 NNaphthalene ug/L
97 NSurr. 1 (Bromobenzene) % 0 NUnidentified Peaks
005 Date Sampled: 9/27/11Site: MW-2 9/29/11 RBFWAnalysis Date:10:29QualNelacUnitResultParameterQualNelacUnitResultParameter
TEST METHOD: EPA 8021B
146 NMethyl-t-butyl ether (MTBE) ug/L 31.6 NBenzene ug/L< 1.0 NToluene ug/L 47.7 NEthylbenzene ug/L8.9 NXylenes, Total ug/L < 1.0 N1,3,5-Trimethylbenzene ug/L
30.1 N1,2,4-Trimethylbenzene ug/L 5.3 NNaphthalene ug/L90 NSurr. 1 (Bromobenzene) % > 10 NUnidentified Peaks
Laboratory Report
ECS-Waterbury
Page 3 of 3CLIENT:PROJECT: Middlebury Mobil
WORK ORDER:DATE RECEIVED:
1109-1418909/27/2011
10/3/2011REPORT DATE:
006 Date Sampled: 9/27/11Site: MW-4 9/29/11 RBFWAnalysis Date:12:12QualNelacUnitResultParameterQualNelacUnitResultParameter
TEST METHOD: EPA 8021B
< 2.0 NMethyl-t-butyl ether (MTBE) ug/L < 1.0 NBenzene ug/L< 1.0 NToluene ug/L < 1.0 NEthylbenzene ug/L< 2.0 NXylenes, Total ug/L < 1.0 N1,3,5-Trimethylbenzene ug/L< 1.0 N1,2,4-Trimethylbenzene ug/L < 2.0 NNaphthalene ug/L101 NSurr. 1 (Bromobenzene) % 0 NUnidentified Peaks
007 Date Sampled: 9/27/11Site: MW-5 9/29/11 RBFWAnalysis Date:10:57QualNelacUnitResultParameterQualNelacUnitResultParameter
TEST METHOD: EPA 8021B
387 NMethyl-t-butyl ether (MTBE) ug/L < 5.0 NBenzene ug/L< 5.0 NToluene ug/L < 5.0 NEthylbenzene ug/L
< 10.0 NXylenes, Total ug/L < 5.0 N1,3,5-Trimethylbenzene ug/L< 5.0 N1,2,4-Trimethylbenzene ug/L < 10.0 NNaphthalene ug/L
93 NSurr. 1 (Bromobenzene) % 1 NUnidentified Peaks
008 Date Sampled: 9/27/11Site: MW-1 9/29/11 RBFWAnalysis Date:10:30QualNelacUnitResultParameterQualNelacUnitResultParameter
TEST METHOD: EPA 8021B
< 2.0 NMethyl-t-butyl ether (MTBE) ug/L < 1.0 NBenzene ug/L< 1.0 NToluene ug/L < 1.0 NEthylbenzene ug/L< 2.0 NXylenes, Total ug/L < 1.0 N1,3,5-Trimethylbenzene ug/L< 1.0 N1,2,4-Trimethylbenzene ug/L < 2.0 NNaphthalene ug/L105 NSurr. 1 (Bromobenzene) % 0 NUnidentified Peaks
009 Date Sampled: 9/27/11Site: MW-8 9/29/11 RBFWAnalysis Date:12:20QualNelacUnitResultParameterQualNelacUnitResultParameter
TEST METHOD: EPA 8021B
7.6 NMethyl-t-butyl ether (MTBE) ug/L < 1.0 NBenzene ug/L< 1.0 NToluene ug/L < 1.0 NEthylbenzene ug/L10.2 NXylenes, Total ug/L 1.2 N1,3,5-Trimethylbenzene ug/L4.6 N1,2,4-Trimethylbenzene ug/L < 2.0 NNaphthalene ug/L100 NSurr. 1 (Bromobenzene) % > 10 NUnidentified Peaks
010 Date Sampled: 9/27/11Site: MW-11 9/29/11 RBFWAnalysis Date:11:45QualNelacUnitResultParameterQualNelacUnitResultParameter
TEST METHOD: EPA 8021B
12.2 NMethyl-t-butyl ether (MTBE) ug/L 2.6 NBenzene ug/L< 1.0 NToluene ug/L 2.4 NEthylbenzene ug/L< 2.0 NXylenes, Total ug/L < 1.0 N1,3,5-Trimethylbenzene ug/L< 1.0 N1,2,4-Trimethylbenzene ug/L < 2.0 NNaphthalene ug/L102 NSurr. 1 (Bromobenzene) % > 10 NUnidentified Peaks
APPENDIX B LOW FLOW SAMPLING FIELD FORMS