DERR-2025-000565

Facilities | Environmental | Geotechnical | Materials 1
Cover Page
Quarterly Groundwater Monitoring
Report—December 2024
Brent Redd Property
148 East Center Street, Monticello, Utah
Facility ID #5000003 Release ID GZQ
January 16, 2025 | Terracon Project No. AL067003
Prepared for:
Utah Department of Environmental Quality
Division of Environmental Response and Remediation
Salt Lake City, Utah
6952 South High Tech Drive, Ste. B
Midvale, Utah 84047
P [phone]
Terracon.com
Facilities | Environmental | Geotechnical | Materials i
Cover Letter
January 16, 2025
Utah Department of Environmental Quality
Division of Environmental Response and Remediation
195 North 1950 West
Salt Lake City, Utah 84114
Attn: Mr. Mark Crim
E:[e-mail]
Re: Quarterly Groundwater Monitoring Report—December 2024
Brent Redd Property
148 East Center Street, Monticello, Utah
Facility Identification No. 5000003, Release ID GZQ
Terracon Project No. AL067003
Dear Mr. Crim:
Terracon Consultants, Inc. (Terracon) is pleased to submit this Quarterly Groundwater
Monitoring Report documenting the sixth quarterly groundwater sampling event conducted
under Work Assignment GZQ-57-TER at the Brent Redd property (Facility ID 5000003,
Release ID GZQ), located at 148 East Center Street, Monticello, Utah.
Terracon has performed this work pursuant to Terracon’s Work Plan GZQ-56-TER, dated
August 21, 2023. This work was conducted under Terracon's contract (Contract Number
216383) with the Division of Environmental Response and Remediation.
We appreciate the opportunity to have performed these services for you. Please contact our
office at [phone] if you have questions regarding this information or if we can
provide any other services.
Sincerely,
Terracon Consultants, Inc.
JR Murphy Craig D. Eaton
Field Scientist Authorized Project Reviewer
UST Sampler #1947 UST Consultant #CC167
Facilities | Environmental | Geotechnical | Materials ii
Table Of Contents
1.0 Introduction ................................................................................ 1
1.1 Site Description ..................................................................................... 1
1.2 Scope of Services ................................................................................... 1
1.3 Standard of Care .................................................................................... 1
1.4 Additional Scope Limitations .................................................................... 1
1.5 Reliance ................................................................................................ 2
2.0 Groundwater Sampling Event......................................................... 2
2.1 Groundwater Sample Collection ............................................................... 2
2.2 General Observations ............................................................................. 3
3.0 Laboratory Analytical Methods ....................................................... 3
4.0 Data Evaluation ........................................................................... 4
4.1 Groundwater Sample Results ................................................................... 4
4.2 Quality Control ....................................................................................... 4
4.3 Plume Stability Evaluation ....................................................................... 5
5.0 Findings and Conclusions .............................................................. 6
APPENDICES
Appendix A Exhibits
Exhibit 1:Topographic Site Overview
Exhibit 2:Site Diagram
Exhibit 3:Groundwater Elevation Map, December 2024
Exhibit 4: TPH-GRO Concentrations, December 2024
Exhibit 5: TPH-DRO Concentrations, December 2024
Exhibit 6:Benzene Concentrations, December 2024
Appendix B Data Tables
Table 1:Well Construction and Groundwater Elevation Data
Table 2:Groundwater Analytical Results
Appendix C Chain of Custody Documentation and Laboratory Data Sheets
Appendix D Mann-Kendall Plume Stability Analysis
Quarterly Groundwater Monitoring Report—December 2024 (Sixth Event)
Brent Redd Property | Monticello, Utah
January 16, 2025 | Terracon Project No. AL067003
Facilities | Environmental | Geotechnical | Materials 1
1.0 Introduction
1.1 Site Description
Terracon conducted a groundwater monitoring event at the Brent Redd property (Facility ID
5000003, Release ID GZQ), located at 148 East Center Street, Monticello, Utah. A
topographic map of the area is provided as Exhibit 1 (Appendix A). The site is currently
operated as the S&S Fusion equipment maintenance shop, which services equipment used
to fuse poly pipe. A site diagram with monitoring well locations is provided as Exhibit 2
(Appendix A).
1.2 Scope of Services
The work objective of Work Assignment GZQ-57-TER was to collect groundwater samples
from eleven existing on- and off-site monitoring wells to assess the current groundwater
conditions. This is the sixth and final quarterly groundwater monitoring event approved
under Work Assignment GZQ-57-TER.
1.3 Standard of Care
Terracon’s services were performed consistent with generally accepted practices of the
profession undertaken in similar studies in the same geographical area during the same
time period. Please note that Terracon does not warrant the work of laboratories, regulatory
agencies, or other third parties supplying information used to prepare the report. These
services were performed in accordance with the scope of services agreed with you, our
client, as reflected in our Work Plan, and were not performed in accordance with ASTM
E1903-19.
1.4 Additional Scope Limitations
Findings, conclusions, and recommendations resulting from these services are based upon
information derived from the on-site activities and other services performed under this
scope of services. Such information is subject to change over time. Certain indicators of the
presence of hazardous substances, petroleum products, or other constituents may have
been latent, inaccessible, unobservable, non-detectable, or not present during these
services, and we cannot represent that the site contains no hazardous substances, toxic
materials, petroleum products, or other latent conditions beyond those identified during this
investigation. Subsurface conditions may vary from those encountered at specific borings or
wells or during other surveys, tests, assessments, investigations, or exploratory services;
the data, interpretations, findings, and recommendations are based solely upon data
obtained at the time and within the scope of these services.
Quarterly Groundwater Monitoring Report—December 2024 (Sixth Event)
Brent Redd Property | Monticello, Utah
January 16, 2025 | Terracon Project No. AL067003
Facilities | Environmental | Geotechnical | Materials 2
1.5 Reliance
This report has been prepared for the exclusive use and reliance of the Utah Department of
Environmental Quality (UDEQ). Use or reliance by any other party is prohibited without the
written authorization of the UDEQ and Terracon.
Reliance on the report by the client and all authorized parties will be subject to the terms,
conditions, and limitations stated in the proposal, report, and Terracon’s Terms and
Conditions. The limitation of liability defined in the Terms and Conditions is the aggregate
limit of Terracon’s liability to the client and all relying parties.
2.0 Groundwater Sampling Event
2.1 Groundwater Sample Collection
On December 9, 2024, Mr. Mark Lilly (UST Groundwater and Soil Sampler GS449) gauged
the depth-to-free product, if present, and depth-to-groundwater in 11 monitoring wells
located at the site and at a hydraulically down-gradient property (Monticello Inn). After
gauging groundwater levels, Mr. Lilly collected groundwater samples from monitoring wells
B-3R, MW-5R, MW-7, MW-14, MW-15, MW-16, MW-17, MW-18, MW-19, MW-20, and MW-
21 on December 10 and 11, 2024. Two quality control samples were shipped with the
samples, consisting of a trip blank and a field blank. The field blank was collected by
pouring laboratory-supplied deionized water through a new bailer and filling sample
containers in a similar manner as the samples collected from the monitoring wells.
Prior to collecting the groundwater samples, each well was purged of three well volumes to
remove stagnant water from the well casings prior to sampling. Monitoring well B-3R purged
dry after approximately 2 gallons of water was removed and monitoring wells MW-15 and
MW-16 purged dry after removing approximately 13 gallons of water each. Groundwater in
these three wells was allowed to recover prior to sampling.
Measurable free product was not identified in any of the 11 monitoring wells gauged during
this sampling event; however, a slight sheen was observed on the purge water from
monitoring well B-3R and very slight to slight apparent petroleum odors were observed in all
of the wells except for MW-21. Purge water was thin spread across the surface in the
vicinity of the well that generated the water and allowed to evaporate or infiltrate into
surface soils. Care was taken to not allow purge water to affect nearby receptors
(stormwater catch basins, other monitoring wells, utilities, etc.) or residential property.
Quarterly Groundwater Monitoring Report—December 2024 (Sixth Event)
Brent Redd Property | Monticello, Utah
January 16, 2025 | Terracon Project No. AL067003
Facilities | Environmental | Geotechnical | Materials 3
2.2 General Observations
Depth-to-water measurements and groundwater elevations are presented in Table 1
(Appendix B). Groundwater elevations at the site were measured to range between
7,022.33 (MW-21) and 7,032.62 (MW-14) feet above mean sea level (msl).
The direction of groundwater flow is generally toward the east (Exhibit 3, Appendix A). The
groundwater gradient and associated flow direction were generally consistent with the flow
directions observed during previous 2023 and 2024 groundwater monitoring events. Free
product was not observed in the monitoring wells during this sampling event. Groundwater
elevations were between 0.67 to 0.81 feet lower than the September 2024 monitoring
event; however, measured elevations are within typical seasonal fluctuations based on
historical gauging from May 2000 to June 2024.
Terracon had previously installed passive light non-aqueous phase liquid (LNAPL) recovery
equipment: Durham Geo SoakEase product-selective absorbent socks and stainless-steel
canisters in monitoring wells B-3R and MW-7; however, the absorbent socks were removed
during previous sampling events. No measurable LNAPL was observed in these wells during
this event and the absorbent socks were not replaced.
3.0 Laboratory Analytical Methods
The groundwater samples were collected and placed in laboratory-prepared containers,
labeled, and placed on ice in a cooler and transported to Chemtech-Ford Laboratory in
Sandy, Utah.
The groundwater samples were submitted for analysis of methyl tertiary-butyl ether,
benzene, toluene, ethylbenzene, total xylenes, naphthalene (MBTEXN), total petroleum
hydrocarbons gasoline-range organics (TPH-GRO), and total petroleum hydrocarbons diesel-
range organics (TPH-DRO), using the United States Environmental Protection Agency (EPA)
analytical methods identified in the following table. The field blank and trip blank were
analyzed for MBTEXN and TPH-GRO.
Analysis Sample Type No. Of Samples Analytical Method
MBTEXN Groundwater 13 EPA Method 8260D
TPH-GRO Groundwater 13 EPA Method 8260B/C
TPH-DRO Groundwater 11 EPA Method 8015C
The executed chain-of-custody form and laboratory data sheets are provided in Appendix C.
Quarterly Groundwater Monitoring Report—December 2024 (Sixth Event)
Brent Redd Property | Monticello, Utah
January 16, 2025 | Terracon Project No. AL067003
Facilities | Environmental | Geotechnical | Materials 4
4.0 Data Evaluation
4.1 Groundwater Sample Results
Results of the groundwater sampling event are summarized in Table 2 (Appendix B).
Sample locations are shown on Exhibit 2 (Appendix A).
As presented in Table 2 (Appendix B), petroleum hydrocarbons were reported above the
laboratory method reporting limits in 10 of the 11 wells sampled.
The TPH-GRO concentrations exceeded the TPH-GRO Initial Screening Level (ISL) in
monitoring wells MW-5R, MW-7, MW-14, MW-15, and MW-18. The TPH-GRO
concentrations exceeded the TPH-GRO Tier 1 Screening Criteria in monitoring wells
B-3R, MW-16, and MW-17.
TPH-DRO concentrations exceeded the TPH-DRO ISL in monitoring wells B-3R, MW-
16, and MW-17. The TPH-DRO concentrations did not exceed the TPH-DRO Tier 1
Screening Criteria in any of the wells sampled.
Benzene concentrations exceeded the benzene ISL in monitoring wells MW-7, MW-
14, MW-19, and MW-20. Benzene concentrations exceeded the benzene Tier 1
Screening Criteria in monitoring wells B-3R, MW-5R, MW-15, MW-16, MW-17, and
MW-18.
Ethylbenzene concentrations exceeded the ISL in monitoring wells B-3R and MW-17.
Isoconcentration contour maps for TPH-GRO, TPH-DRO, and benzene are presented as
Exhibits 4, 5, and 6 (Appendix A), respectively.
4.2 Quality Control
Quality control for the sampling program was provided by using standardized sample
collection and handling methods, documenting pertinent field information, and keeping
chain-of-custody records, as well as using a Utah-certified laboratory. The sampling
procedures followed Terracon’s Standard Operating Procedures and industry practices.
A review of the field procedures indicates that standard operating procedures were followed
with regards to sample collection, handling, and documentation. The quality control samples
(field and trip blank) did not have concentrations above the respective laboratory reporting
limits.
Based on the laboratory analytical report, the samples were extracted and analyzed within
appropriate sample holding times. Internal laboratory QA/QC procedures and results are
presented in the laboratory report and were within acceptable limits set by the laboratory,
except where noted.
Quarterly Groundwater Monitoring Report—December 2024 (Sixth Event)
Brent Redd Property | Monticello, Utah
January 16, 2025 | Terracon Project No. AL067003
Facilities | Environmental | Geotechnical | Materials 5
4.3 Plume Stability Evaluation
Groundwater monitoring has been conducted at the former Brent Redd property since the
early 1990s. To better understand whether the impacted groundwater plume is expanding,
contracting, or remaining stable is important to evaluate current and future potential
receptors and associated risks to those receptors. To evaluate plume stability, Terracon
performed statistical analysis of the groundwater concentrations in ten of the monitoring
wells within the dissolved benzene plume, located both onsite (B-3R, MW-5R, MW-14, MW-
15, MW-16, MW-17, MW-18, and MW-19) and offsite on the Monticello Inn property (MW-7
and MW-20). Benzene was selected as the primary driver for risk at the site as it is present
throughout the impacted area, is mobile in groundwater, can volatilize and migrate in the
vapor phase, and it is a known carcinogen.
Concentrations of benzene in each of the wells for the past ten sampling events from 2022
through 2024 were entered into the Mann-Kendall statistical evaluation model. Mann-
Kendall evaluates trends in numbers (i.e., increasing, decreasing, or remaining stable) by
comparing individual events to all other events in the same location at the site and
assigning a “+1” value if the current event was higher than the prior event, “-1” value if the
current event was lower than the previous event, or “0” if the two events had the same
value. The results of the event comparisons are summed, and the resulting number (the
Mann-Kendall value or “S”) is evaluated compared to a confidence level chart with the
Mann-Kendall value (“S”) on one axis and the number of sampling events on the other axis.
The result will fall into one of three categories of confidence (i.e., <70% confidence—no
trend, 70-90% confidence—trend may be present, or 90%+ confidence—trend is present).
If the result is within the “no trend” area, the plume is considered stable. If the result is
within the ”trend may be present” area, the plume may be expanding (positive S value) or
contracting (negative S value). If the result is within the “trend is present” area, the plume
has a greater than 90% confidence to be expanding (positive S value) or contracting
(negative S value).
The results for each well are evaluated together as a group to determine whether a pattern
exists relating to plume stability. This statistical analysis is best performed when there are 4
or more events for the model to evaluate. In this case, we have ten separate wells each
with 10 sampling events (except for B-3R that only had six sampling events). This level of
data increases confidence in the resulting statistical results.
The results of the Mann-Kendall statistical analysis showed six wells were “stable,” two wells
were “potentially diminishing” (B-3R and MW-17) and two wells are “expanding” (MW-14
and MW-16). The two “expanding” wells are located near the center of the plume. One of
the “potentially diminishing” wells is in the center of the plume and the other is on the up-
gradient edge of the plume. The results of the statistical analysis show that the plume is
generally stable with some variability in concentration trends in the center of the plume.
The Mann-Kendall statistical evaluation model is included in Appendix D.
Quarterly Groundwater Monitoring Report—December 2024 (Sixth Event)
Brent Redd Property | Monticello, Utah
January 16, 2025 | Terracon Project No. AL067003
Facilities | Environmental | Geotechnical | Materials 6
5.0 Findings and Conclusions
Petroleum hydrocarbon concentrations remain elevated in groundwater at the site and at
the hydraulically down-gradient Monticello Inn property. Benzene exceeds its Tier 1
Screening Criteria in all but two of the onsite monitoring wells and exceeds its ISL in all the
wells sampled except MW-21 in the farthest down-gradient location on the Monticello Inn
property. Benzene impacts extend offsite to both the north under Center Street and the east
under the Monticello Inn property. Concentrations of benzene exceeding its Tier 1 Screening
Criteria exist beneath the onsite building and beneath the northwestern portion of the
Monticello Inn building.
TPH-GRO exceeds its Tier 1 Screening Criteria in three of the onsite monitoring wells and is
present beneath the onsite building. TPH-GRO concentrations exceed its ISL in all the wells
sampled except MW-19 east of the onsite building, MW-20 in the north-central area of the
Monticello Inn property, and MW-21 in the farthest down-gradient location on the Monticello
Inn property. TPH-GRO impacts extend offsite to both the north under Center Street and the
east under the Monticello Inn property. Concentrations of TPH-GRO exceeding its Tier 1
Screening Criteria appear to be limited to the site.
Monitoring wells B-3R, MW-16, and MW-17, located north of the onsite building, continue to
exhibit the highest petroleum constituent concentrations in the sampled monitoring wells.
Although LNAPL was previously observed in monitoring wells B-3R, MW-5, MW-7, and MW-
16 between 2002 and 2013, no measurable LNAPL has been observed since 2013.
A statistical analysis of plume stability showed that the plume is generally stable with some
variability in concentration trends in the center of the plume. Depth-to-groundwater in the
plume area ranges from 13.85 to 16.29 feet below the tops of the well casings, which are
generally within six inches of the ground surface.
A vapor study was conducted by Terracon concurrently with this groundwater monitoring
event that was reported under separate cover. The vapor study included collection of indoor
air samples from both the onsite building and the Monticello Inn building, crawl space air
samples from the Monticello Inn building, an outdoor air sample collected outside the
Monticello Inn office, and two sub-slab soil vapor samples collected from beneath the onsite
building’s slab-on-grade office and from beneath the basement of the Monticello Inn office
space.
The Vapor Study Report—December 2024 (Terracon; January 16, 2025) concluded that
several contaminants of concern typical of fuel releases (i.e., benzene, toluene,
ethylbenzene, xylenes, and 1,2,4-trimethylbenzene) were reported in indoor air samples,
crawl space air samples, and/or in the outdoor air sample. Of the constituents reported,
benzene is the only one that was reported at a concentration exceeding EPA’s Residential Air
Regional Screening Level (RSL) and in one sample the Industrial Air RSL. Although benzene
is one of the primary constituents of concern in the groundwater plume, neither benzene
nor any other volatile organic compounds (VOCs) analyzed were reported in either of the
Quarterly Groundwater Monitoring Report—December 2024 (Sixth Event)
Brent Redd Property | Monticello, Utah
January 16, 2025 | Terracon Project No. AL067003
Facilities | Environmental | Geotechnical | Materials 7
sub-slab vapor samples, which indicates it is unlikely benzene or other VOCs are
accumulating beneath the buildings and intruding into the buildings through cracks or other
penetrations. The more likely source of the benzene and other VOCs reported at the site is
from external sources such as vehicle exhaust (i.e., incomplete combustion of gasoline)
from vehicles travelling on Center Street or idling in the Monticello Inn parking lot.
Concentrations of dissolved petroleum hydrocarbons exceeding UDEQ screening levels
remain on- and off-site. Based on the elevated concentrations of dissolved phase benzene
and TPH observed at monitoring wells B-3R, MW-16, and MW-17, a petroleum hydrocarbon
source may remain in the subsurface. The impacted groundwater plume appears to be
stable with some fluctuations in concentrations in the center of the plume; however,
petroleum vapors from the groundwater plume do not appear to be intruding into the
overlying buildings.
Appendix A
Exhibits
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Exhibit
terracon.comPH. 801-545-8500
6952 S High Tech Dr, Ste B
Midvale, UT
Reviewed By:
Drawn By:
Jan 2025
Date:
AL067003
Project No.:
Brent Redd Property
148 East Center Street
Monticello, Utah
Groundwater Elevation Map, December 2024
3
ABA
AST
DATA SOURCES:
ESRI - Basemaps
&
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8

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9

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t
MW-14
7032.62
B-3R
7031.70
MW-19
7029.62
MW-17
7030.28
MW-18
7029.73
MW-16
7030.72
MW-15
7030.85
MW-5R
7030.22
MW-20
7027.06
MW-7
7026.25
MW-21
7022.33
0 40 8020
Feet
³
³@A Monitoring Well with Groundwater Elevation (ft), December 2024
Groundwater Contour (ft), December 2024
&Approximate Groundwater Flow Direction
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Exhibit
terracon.comPH. 801-545-8500
6952 S High Tech Dr, Ste B
Midvale, UT
Reviewed By:
Drawn By:
Jan 2025
Date:
AL067003
Project No.:
Brent Redd Property
148 East Center Street
Monticello, Utah
TPH-GRO Concentrations, December 2024
4
ABA
AST
DATA SOURCES:
ESRI - Basemaps
@A
@A
@A
@A
@A@A
@A
@A
@A
@A
@A
MW-14
1,590
B-3R
29,200
MW-19
ND
MW-17
20,500
MW-18
1,830
MW-16
15,500
MW-15
6,010
MW-5R
2,780
MW-20
ND
MW-7
4,500
MW-21
ND
0 40 8020
Feet
³
³@A Monitoring Well with TPH-GRO Concentration (µg/l), December 2024
TPH-GRO Concentrations (ug/l), December 2024
>10,000 (Exceeds UDEQ Tier 1)
1,000 - 10,000 (Exceeds UDEQ ISL)
ND - Not detected at or above laboratory reporting limit
µg/l - micrograms per liter
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Exhibit
terracon.comPH. 801-545-8500
6952 S High Tech Dr, Ste B
Midvale, UT
Reviewed By:
Drawn By:
Jan 2025
Date:
AL067003
Project No.:
Brent Redd Property
148 East Center Street
Monticello, Utah
TPH-DRO Concentrations, December 2024
5
ABA
AST
DATA SOURCES:
ESRI - Basemaps
@A
@A
@A
@A
@A@A
@A
@A
@A
@A
@A
MW-14
ND
B-3R
7,400
MW-19
ND
MW-17
3,300
MW-18
ND
MW-16
1,800
MW-15
ND
MW-5R
ND
MW-20
ND
MW-7
ND
MW-21
ND
0 40 8020
Feet
³
³@A Monitoring Well with TPH-DRO Concentration (µg/l), December 2024
TPH-DRO Concentration (µg/l), December 2024
1,000 - 10,000 (Exceeds UDEQ ISL)
ND - Not detected at or above laboratory reporting limit
µg/l - micrograms per liter
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Exhibit
terracon.comPH. 801-545-8500
6952 S High Tech Dr, Ste B
Midvale, UT
Reviewed By:
Drawn By:
Jan 2025
Date:
AL067003
Project No.:
Brent Redd Property
148 East Center Street
Monticello, Utah
Benzene Concentrations, December 2024
6
ABA
AST
DATA SOURCES:
ESRI - Basemaps
@A
@A
@A
@A
@A@A
@A
@A
@A
@A
@A
MW-14
16
B-3R
4,900
MW-19
11
MW-17
10,700
MW-18
1,580
MW-16
11,400
MW-15
3,520
MW-5R
768
MW-20
15
MW-7
39
MW-21
ND
0 40 8020
Feet
³
³@A Monitoring Well with Benzene Concentration (µg/l), December 2024
Benzene Concentration (ug/l), December 2024
> 300 µg/l (Exceeds UDEQ Tier 1)
5 - 300 µg/l (Exceeds UDEQ ISL)
ND - Not detected at or above laboratory reporting limit
µg/l - micrograms per liter
Appendix B
Data Tables
Table 1
Brett Redd Facility
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Well Construction and Groundwater Elevation Data
Well
ID
Well
Diameter
(inches)
Screened
Interval
(ft-bgs)
Well
Depth
(feet)
Top of
Casing
Elevation
(feet)
Date
Depth to
Water
(ft-btoc)
Ground Water
Elevation
(feet)
99.42 11/08/91 15.76 83.66
10/10/95 10.41 7,036.73
02/01/96 14.49 7,032.65
09/10/96 15.71 7,031.43
12/10/96 14.54 7,032.60
03/12/97 9.70 7,037.44
06/12/97 9.28 7,037.86
10/01/97 10.36 7,036.78
12/10/97 12.51 7,034.63
03/26/98 11.39 7,035.75
07/14/98 10.82 7,036.32
01/11/99 13.30 7,033.84
04/28/99 12.35 7,034.79
07/20/99 12.44 7,034.70
10/13/99 12.38 7,034.76
05/24/00 13.15 7,033.99
08/09/00 12.76 7,034.38
11/07/00 12.42 7,034.72
02/08/01 13.49 7,033.65
05/08/01 13.00 7,034.14
08/14/01 12.33 7,034.81
08/05/02 17.43 7,029.71
11/13/02 18.41 7,028.74
12/05/02 18.94 7,028.20
01/19/03 19.42 7,027.72
02/19/03 19.58 7,027.56
03/20/03 17.00 7,030.14
05/27/03 19.34 7,027.80
03/23/04 18.93 7,028.21
10/10/06 10.79 7,036.35
05/08/07 14.42 7,032.72
11/12/09 14.28 7,032.86
06/29/10 9.82 7,037.32
02/14/13 16.81 7,030.33
09/10/13 17.82 7,029.32
11/19/13 17.85 7,029.29
07/23/14 19.15 7,027.99
05/14/15 15.13 7,032.01
05/03/16 13.42 7,033.72
11/18/16 15.68 7,031.46
06/06/18 18.88 7,028.26
04/16/19 10.32 7,036.82
10/09/19 NM --
01/27/22 NM --
B-2 7047.1438.7322-374
Well Abandoned
Page 1 of 8 Terracon Consultants, Inc.
Table 1
Brett Redd Facility
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Well Construction and Groundwater Elevation Data
Well
ID
Well
Diameter
(inches)
Screened
Interval
(ft-bgs)
Well
Depth
(feet)
Top of
Casing
Elevation
(feet)
Date
Depth to
Water
(ft-btoc)
Ground Water
Elevation
(feet)
7047.62 05/24/00 13.87 7,033.75
08/09/00 13.90 7,033.62
11/07/00 13.19 7,034.33
02/08/01 15.28 7,032.24
05/08/01 13.50 7,034.02
08/14/01 12.85 7,034.67
08/05/02 17.93 7,029.59
11/13/02 18.96 7,028.56
12/05/02 19.15 7,028.37
01/19/03 NM NM
02/19/03 NM LNAPL
03/20/03 17.82 7,029.70
05/27/03 NM LNAPL
03/23/04 19.53 7,027.99
10/09/06 11.90 7,035.62
05/08/07 14.99 LNAPL (0.03')
11/12/09 14.69 7,032.83
06/29/10 10.33 7,037.19
02/14/13 17.32 LNAPL (0.07')
09/10/13 18.29 LNAPL (0.10')
11/18/13 18.31 LNAPL (0.07')
07/23/14 19.84 7,027.68
05/14/15 15.81 7,031.71
05/03/16 14.20 7,033.32
11/18/16 16.08 7,031.44
06/06/18 19.31 7,028.21
04/16/19 10.93 7,036.59
10/09/19 15.64 7,031.88
06/25/20 16.32 7,031.20
01/27/22 19.52 7,028.00
04/21/22 19.48 7,028.04
07/28/22 19.70 7,027.82
10/20/22 19.50 7,028.02
09/26/23 14.45 7,033.07
12/12/23 15.62 7,031.90
03/20/24 12.38 7,035.14
06/25/24 13.54 7,033.98
09/23/24 15.06 7,032.46
12/09/24 15.82 7,031.70
B-3R 2 10-20 20.00 7047.52
Page 2 of 8 Terracon Consultants, Inc.
Table 1
Brett Redd Facility
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Well Construction and Groundwater Elevation Data
Well
ID
Well
Diameter
(inches)
Screened
Interval
(ft-bgs)
Well
Depth
(feet)
Top of
Casing
Elevation
(feet)
Date
Depth to
Water
(ft-btoc)
Ground Water
Elevation
(feet)
10/11/95 10.43 7,034.67
02/01/96 14.46 7,030.64
06/21/96 15.61 7,029.49
09/10/96 15.50 7,029.60
12/10/96 14.50 7,030.60
03/12/97 10.28 7,034.82
06/12/97 9.26 7,035.84
10/01/97 10.27 7,034.83
12/10/97 12.43 7,032.67
03/26/98 11.50 7,033.60
07/14/98 9.85 7,035.25
01/11/99 13.38 7,031.72
04/28/99 12.87 7,032.23
07/20/99 12.62 7,032.48
10/13/99 12.52 7,032.58
05/24/00 13.25 7,031.85
08/09/00 12.84 7,032.26
11/07/00 12.86 7,032.24
02/08/01 14.93 7,030.17
05/08/01 13.20 7,031.90
08/14/01 11.50 7,033.60
08/05/02 17.18 7,027.92
11/13/02 18.50 7,026.60
12/05/02 18.57 7,026.53
01/19/03 19.01 7,026.09
02/19/03 19.24 7,025.86
03/20/03 16.81 7,028.29
05/27/03 18.85 7,026.25
03/23/04 18.28 7,026.82
10/09/06 11.43 LNAPL (0.11')
05/08/07 14.50 LNAPL (0.15')
11/12/09 14.06 LNAPL (0.01')
06/29/10 9.84 7,035.26
02/14/13 16.58 7,028.52
09/10/13 16.03 7,029.07
11/18/13 17.49 7,027.61
07/22/14 18.66 7,026.44
05/14/15 15.12 7,029.98
05/03/16 13.70 7,031.40
11/18/16 15.60 7,029.50
06/06/18 NM --
04/16/19 NM --
10/09/19 NM --
01/27/22 18.30 7,026.42
04/21/22 18.11 7,026.61
07/28/22 19.22 7,025.50
10/20/22 18.34 7,026.38
09/26/23 13.17 7,031.55
12/12/23 14.15 7,030.57
03/20/24 10.67 7,034.05
06/25/24 11.97 7,032.75
09/23/24 13.80 7,030.92
12/09/24 14.50 7,030.22
7044.72
7045.10
Well Abandoned
MW-5
MW-5R
4 8-23
2 10-30 29.64
22.97
Well Casing
Damaged
Page 3 of 8 Terracon Consultants, Inc.
Table 1
Brett Redd Facility
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Well Construction and Groundwater Elevation Data
Well
ID
Well
Diameter
(inches)
Screened
Interval
(ft-bgs)
Well
Depth
(feet)
Top of
Casing
Elevation
(feet)
Date
Depth to
Water
(ft-btoc)
Ground Water
Elevation
(feet)
10/11/95 10.25 7,030.79
02/01/96 14.31 7,026.73
06/21/96 14.92 7,026.12
09/10/96 15.05 7,025.99
12/10/96 14.51 7,026.53
03/12/97 9.83 7,031.21
06/12/97 8.72 7,032.32
10/01/97 9.97 7,031.07
12/10/97 12.24 7,028.80
03/26/98 11.35 7,029.69
07/14/98 9.99 7,031.05
01/11/99 13.03 7,028.01
04/28/99 12.46 7,028.58
07/20/99 11.84 7,029.20
10/13/99 11.91 7,029.13
05/24/00 12.49 7,028.55
08/09/00 12.36 7,028.68
11/07/00 12.82 7,028.22
02/08/01 14.67 7,026.37
05/08/01 12.80 7,028.24
08/14/01 12.10 7,028.94
08/05/02 16.75 7,024.29
11/13/02 16.70 7,024.34
12/05/02 18.03 7,023.01
01/19/03 NM NM
02/19/03 18.45 7,022.59
03/20/03 NM NM
05/27/03 NM NM
03/23/04 NM NM
11/12/09 14.36 LNAPL (0.05')
06/29/10 9.61 7,031.43
02/14/13 NM NM
09/10/13 16.09 LNAPL (0.01')
11/18/13 16.53 LNAPL (0.03')
07/22/14 17.82 7,023.22
05/13/15 14.68 7,026.36
05/03/16 13.42 7,027.62
11/18/16 15.52 7,025.52
6/6/2018 17.81 7,023.23
4/16/2019 9.95 7,031.09
10/09/19 14.05 7,026.99
06/25/20 14.57 7,026.47
01/27/22 17.99 7,023.05
04/21/22 17.68 7,023.36
07/28/22 18.45 7,022.59
10/20/22 18.00 7,023.04
09/26/23 12.96 7,028.08
12/12/23 13.19 7,027.85
03/20/24 8.70 7,032.34
06/25/24 9.67 7,031.37
09/23/24 14.10 7,026.94
12/09/24 14.79 7,026.25
MW-7 4 8-23 22.61 7041.04
Page 4 of 8 Terracon Consultants, Inc.
Table 1
Brett Redd Facility
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Well Construction and Groundwater Elevation Data
Well
ID
Well
Diameter
(inches)
Screened
Interval
(ft-bgs)
Well
Depth
(feet)
Top of
Casing
Elevation
(feet)
Date
Depth to
Water
(ft-btoc)
Ground Water
Elevation
(feet)
05/24/00 12.99 7,034.73
08/09/00 12.64 7,035.08
11/07/00 12.30 7,035.42
02/08/01 14.20 7,033.52
05/08/01 12.70 7,035.02
08/14/01 11.98 7,035.74
08/05/02 17.04 7,030.68
11/13/02 18.10 7,029.63
12/05/02 18.66 7,029.07
01/19/03 19.19 7,028.53
02/19/03 19.42 7,028.31
03/20/03 17.06 7,030.66
05/27/03 19.21 7,028.51
03/23/04 18.93 7,028.79
10/10/06 10.95 7,036.77
05/09/07 13.92 7,033.80
11/12/09 13.96 7,033.76
06/29/10 9.43 7,038.29
02/14/13 16.58 7,031.14
09/10/13 17.57 7,030.15
11/19/13 17.67 7,030.05
07/23/14 18.95 7,028.77
05/14/15 15.01 7,032.71
05/03/16 13.29 7,034.43
11/18/16 15.26 7,032.46
06/06/18 18.62 7,029.10
04/16/19 10.33 7,037.39
10/09/19 14.66 7,033.06
06/25/20 15.38 7,032.34
01/27/22 19.21 7,028.51
04/21/22 19.16 7,028.56
07/28/22 20.44 7,027.28
10/20/22 19.38 7,028.34
09/26/23 13.75 7,033.97
12/12/23 14.95 7,032.77
03/20/24 11.65 7,036.07
06/25/24 12.95 7,034.77
09/23/24 14.34 7,033.38
12/09/24 15.10 7,032.62
MW-14 2 13-23 7047.7222.75
Page 5 of 8 Terracon Consultants, Inc.
Table 1
Brett Redd Facility
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Well Construction and Groundwater Elevation Data
Well
ID
Well
Diameter
(inches)
Screened
Interval
(ft-bgs)
Well
Depth
(feet)
Top of
Casing
Elevation
(feet)
Date
Depth to
Water
(ft-btoc)
Ground Water
Elevation
(feet)
05/27/03 19.61 7,026.96
03/23/04 19.22 7,027.35
10/09/06 12.41 7,034.16
05/08/07 15.10 LNAPL (0.01')
05/05/16 14.34 7032.23
11/18/16 15.98 7,030.59
06/06/18 19.39 7,027.18
04/16/19 10.63 7,035.94
10/09/19 15.33 7,031.24
06/25/20 16.12 7,030.45
01/27/22 19.66 7,026.91
04/21/22 19.51 7,027.06
07/28/22 20.76 7,025.81
10/20/22 19.77 7,026.80
09/26/23 14.40 7,032.17
12/12/23 15.59 7,030.98
03/20/24 12.89 7,033.68
06/25/24 13.57 7,033.00
09/23/24 15.01 7,031.56
12/09/24 15.72 7,030.85
05/27/03 20.06 7,026.81
03/23/04 19.66 7,027.21
10/09/06 12.38 7,034.49
05/08/07 14.52 LNAPL (0.02')
11/12/09 15.06 LNAPL (0.01')
06/29/10 10.62 LNAPL (0.01')
02/14/13 17.59 7,029.28
09/10/13 15.16 7,031.71
11/19/13 18.56 7,028.31
07/22/14 19.76 7,027.11
05/14/15 16.10 7,030.77
05/03/16 14.55 7,032.32
11/18/16 16.42 7,030.45
06/06/18 19.64 7,027.23
04/16/19 11.05 7,035.82
10/09/19 15.73 7,031.14
06/25/20 16.43 7,030.44
01/27/22 20.01 7,026.86
04/21/22 19.85 7,027.02
07/28/22 21.07 7,025.80
10/20/22 20.12 7,026.75
09/26/23 14.80 7,032.07
12/12/23 15.88 7,030.99
03/20/24 12.71 7,034.16
06/25/24 13.75 7,033.12
09/23/24 15.48 7,031.39
12/09/24 16.15 7,030.72
7046.57
MW-16 4 12.5-22.5 22.82 7046.87
MW-15 4 12-22 22.7
Page 6 of 8 Terracon Consultants, Inc.
Table 1
Brett Redd Facility
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Well Construction and Groundwater Elevation Data
Well
ID
Well
Diameter
(inches)
Screened
Interval
(ft-bgs)
Well
Depth
(feet)
Top of
Casing
Elevation
(feet)
Date
Depth to
Water
(ft-btoc)
Ground Water
Elevation
(feet)
05/27/03 20.28 7,026.29
03/23/04 19.77 7,026.80
10/09/06 12.31 7,034.26
05/08/07 15.42 7,031.15
11/12/09 15.63 7,030.94
06/29/10 11.12 7,035.45
02/14/13 17.79 7,028.78
09/10/13 18.60 7,027.97
11/19/13 18.72 7,027.85
07/22/14 19.93 7,026.64
05/13/15 15.30 7,031.27
05/04/16 14.71 7,031.86
11/18/16 16.87 7,029.70
06/06/18 19.84 7,026.73
04/16/19 11.34 7,035.23
10/09/19 16.08 7,030.49
06/25/20 18.73 7,027.84
01/27/22 19.90 7,026.67
04/21/22 19.75 7,026.82
07/28/22 20.92 7,025.65
10/20/22 20.04 7,026.53
09/26/23 14.84 7,031.73
12/12/23 15.82 7,030.75
03/20/24 12.13 7,034.44
06/25/24 13.52 7,033.05
09/23/24 15.60 7,030.97
12/09/24 16.29 7,030.28
05/27/03 18.49 7,025.89
03/23/04 17.96 7,026.42
10/09/06 10.56 7,033.82
05/08/07 14.09 7,030.29
11/12/09 14.04 7,030.34
06/29/10 9.36 7,035.02
02/14/13 15.97 7,028.41
09/10/13 16.75 7,027.63
11/19/13 16.89 LNAPL (0.01')
07/22/14 18.06 7,026.32
05/14/15 14.49 7,029.89
05/04/16 12.95 7,031.43
11/18/16 15.17 7,029.21
06/06/18 18.01 7,026.37
04/16/19 9.19 7,035.19
10/09/19 14.24 7,030.14
06/25/20 14.89 7,029.49
01/27/22 18.29 7,026.09
04/21/22 18.09 7,026.29
07/28/22 19.21 7,025.17
10/20/22 18.35 7,026.03
09/26/23 13.19 7,031.19
12/12/23 14.14 7,030.24
03/20/24 9.41 7,034.97
06/25/24 11.74 7,032.64
09/23/24 13.97 7,030.41
12/09/24 14.65 7,029.73
MW-18 2 5-25 24.78 7044.38
25.975 7046.57MW-17 2 6.5-26.5
Page 7 of 8 Terracon Consultants, Inc.
Table 1
Brett Redd Facility
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Well Construction and Groundwater Elevation Data
Well
ID
Well
Diameter
(inches)
Screened
Interval
(ft-bgs)
Well
Depth
(feet)
Top of
Casing
Elevation
(feet)
Date
Depth to
Water
(ft-btoc)
Ground Water
Elevation
(feet)
01/27/22 19.09 7,026.18
04/21/22 18.89 7,026.38
07/28/22 20.08 7,025.19
10/20/22 19.25 7,026.02
09/26/23 14.12 7,031.15
12/12/23 15.05 7,030.22
03/20/24 10.97 7,034.30
06/25/24 12.71 7,032.56
09/23/24 14.97 7,030.30
12/09/24 15.65 7,029.62
01/27/22 17.27 7,023.64
04/21/22 16.94 7,023.97
07/28/22 17.65 7,023.26
10/20/22 17.28 7,023.63
09/26/23 12.22 7,028.69
12/12/23 12.69 7,028.22
03/20/24 8.61 7,032.30
06/25/24 9.60 7,031.31
09/23/24 13.17 7,027.74
12/09/24 13.85 7,027.06
01/27/22 18.72 7,018.95
04/21/22 18.20 7,019.47
07/28/22 18.50 7,019.17
10/20/22 18.49 7,019.18
09/26/23 12.87 7,024.80
12/12/23 12.46 7,025.21
03/20/24 7.15 7,030.52
06/25/24 7.15 7,030.52
09/23/24 14.53 7,023.14
12/09/24 15.34 7,022.33
NOTES:
ft-bgs = Feet below ground surface.
ft-btoc = Feet below top of casing.
NM = Not measured.
LNAPL = Light non-aqueous phase liquid
29.70MW-19 2 10-30
10-30MW-20 2
7037.67MW-21 2 8-28 27.75
7045.27
7040.9130.00
Page 8 of 8 Terracon Consultants, Inc.
Table 2
Brent Redd Property
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Groundwater Analytical Results
Sample
Location
Sample
Date
Depth to
Water
(ft-btoc)
TPH-GRO
(µg/L)
TPH-DRO
(µg/L)
MTBE
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethyl-
benzene
(µg/L)
Total
Xylene
(µg/L)
Naph-
thalene
(µg/L)
1,000 1,000 200 5 1,000 700 10,000 700
10,000 10,000 200 300 3,000 4,000 10,000 700
11/08/91 15.76 <200 NA NA 40.8 39.7 23 61.2 <5
10/10/95 10.41 <500 NA NA 18.7 2.4 <2 9.3 <2
02/01/96 14.49 <500 NA NA 12.8 <2 <2 <6 <2
09/10/96 15.71 <500 NA NA <2 13.5 5.2 39.4 4
12/10/96 14.54 <500 NA NA 23.6 <2 <2 <6 <2
03/12/97 9.70 1,500 NA 456 302 <10 <10 <30 <10
06/12/97 9.28 <500 NA 218 235 5.6 7.8 9.7 <2
10/01/97 10.36 <500 NA 115 137 3.5 6.4 <6 <2
12/10/97 12.51 <500 NA 95.2 53.9 <2 2.4 <6 <2
03/26/98 11.39 <500 NA 72.2 32.1 <2 <2 <6 <2
07/14/98 10.82 <500 NA 89.5 146 <2 <2 <6 <2
01/11/99 13.30 <500 NA 334 80.9 <2 <2 <6 <2
04/28/99 12.35 <500 NA 242 54.5 <2 <2 <6 <2
07/20/99 12.44 <500 NA 166 122 <2 <2 <6 <2
10/13/99 12.38 <500 NA 109 82.5 <2 <2 <6 <2
05/24/00 13.15 3,800 NA 199 1,100 27.3 13.5 69.9 <10
08/09/00 12.76 1,800 NA 209 684 19.3 19.0 22.4 <2
11/07/00 12.42 6,300 NA 123 1,280 62.6 29.2 57.6 <5
02/08/01 13.49 <500 NA 60.3 74.1 4.6 2.9 <6 <2
05/08/01 13.00 3,000 NA 236 885 46.5 51.8 58.9 6.0
08/14/01 12.33 <500 NA 125 32.3 <2 2.1 <6 3.2
08/08/02 17.43 <500 <500 147 <2 5.0 <10 <30 <10
11/14/02 18.41 <500 <500 86.7 <2 <2 <2 <6 <2
02/19/03 19.58 <500 <500 83.8 12.6 <2 <2 <6 <2
05/28/03 19.34 <500 <500 <2 4.6 <2 <2 <6 <2
03/24/04 18.93 <500 <500 94 22 3 <2 <6 <2
10/10/06 10.79 54 <2,000 194 10 <1 <1 <3 <1
05/08/07 14.42 <50 <2,000 376 2 <1 <1 <3 <1
11/12/09 14.28 <20 <500 710 16 <2 <2 <2 <2
06/29/10 9.82 1,300 636 523 1,260 <2 5.99 4.81 3.37
02/14/13 16.81 <50 <1,000 109 <1 <1 <1 <3 <2
09/10/13 17.82 <50 <1,000 22 <1 <1 <1 <3 <2
11/16/13 17.85 <50 <1,000 5 <1 <1 <1 <3 <2
07/22/14 19.15 <50 <1,000 1 <1 <1 <1 <3 <2
05/14/15 15.13 <50 <1,000 2 1 <1 1 6 2
05/03/16 13.42 <222 <1,000 9 <2 <5 <5 <5 <5
11/18/16 15.68 <50 <1,000 <2 <2 <5 <5 <5 <5
06/06/18 18.88 <125 <1,000 7 <5 <12 <12 <12 <12
04/16/19 10.32 <125 <1,000 59 15 <12 <12 <12 <12
10/09/19 NM
06/25/20 NM
Initial Screening Levels (µg/L)
TIER 1 Screening Criteria (µg/L)
Well abandoned
Not sampled as per Work Assignment GZQ-49-TER
Not sampled as per Work Assignment GZQ-49-TER
B-2
Page 1 of 9 Terracon Consultants, Inc.
Table 2
Brent Redd Property
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Groundwater Analytical Results
Sample
Location
Sample
Date
Depth to
Water
(ft-btoc)
TPH-GRO
(µg/L)
TPH-DRO
(µg/L)
MTBE
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethyl-
benzene
(µg/L)
Total
Xylene
(µg/L)
Naph-
thalene
(µg/L)
1,000 1,000 200 5 1,000 700 10,000 700
10,000 10,000 200 300 3,000 4,000 10,000 700
Initial Screening Levels (µg/L)
TIER 1 Screening Criteria (µg/L)
05/24/00 13.87 114,000 NA <200 17,300 9,500 727 8,160
08/09/00 13.90 149,100 NA <100 18,200 7,830 989 8,660 240
11/07/00 13.19 115,500 NA <100 18,200 5,790 826 6,910 181
02/08/01 15.28 118,600 NA <500 19,500 10,200 1,010 8,440 <500
05/08/01 13.50 92,700 NA <100 15,100 11,400 672 6,890 213
08/14/01 12.85 120,800 NA <200 20,700 18,200 647 9,110 350
08/08/02 17.93 139,000 7,700 <1,000 25,100 18,500 968 9,510 <1,000
11/13/02 18.96
02/19/03 NM
05/27/03 NM
03/23/04 19.53
10/09/06 11.90 74,600 <2,000 <5 19,200 8,970 1,130 9,720 338
05/08/07 14.99
11/12/09 14.69 50,000 12,000 <40 18,000 2,500 1,400 10,000 380
06/29/10 10.33 47,900 29,200 <20 23,600 1,390 1,360 11,000 418
02/14/13 17.32
09/10/13 18.29
11/18/13 18.31
07/22/14 19.84
05/14/15 15.81 43,500 3,600 <1 17,100 277 1,050 9,580 443
05/03/16 14.20 30,100 4,700 <5 11,800 176 810 6,380 390
11/18/16 16.08 36,000 8,900 <200 12,700 <500 1,210 8,600 <500
06/06/18 19.31 36,200 10,300 <5 10,100 194 1,050 6,840 406
04/17/19 10.93 32,300 16,400 <5 5,620 125 1,150 6,060 375
10/09/19 15.64 39,000 15,400 <5 6,850 154 1,520 9,440 406
06/25/20 16.32 29,700 9,000 <100 8,040 <250 1,070 6,760 318
01/27/22 19.52
04/21/22 19.48
07/28/22 19.70
10/20/22 19.50
09/27/23 14.45 26,300 7,000 <5 5,930 80 1,200 5,080 313
12/12/23 15.62 25,300 8,900 <5 5,440 103 1,070 4,980 319
03/20/24 12.38 27,700 8,300 <50 4,090 <125 1,170 4,950 398
06/25/24 13.54 29,400 8,200 <8 3,440 73 1,150 5,240 365
09/24/24 15.06 26,500 5,900 <8 3,490 81 1,180 5,190 310
12/10/24 15.82 29,200 7,400 <8 4,900 126 1,200 5,340 373
LNAPL
LNAPL
LNAPL
Insufficient water column
LNAPL
Insufficient water column
Insufficient water column
LNAPL
Insufficient water column
LNAPL
LNAPL
LNAPL
Not Sampled - purged dry with no recovery after 24 hoursB-3R
Page 2 of 9 Terracon Consultants, Inc.
Table 2
Brent Redd Property
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Groundwater Analytical Results
Sample
Location
Sample
Date
Depth to
Water
(ft-btoc)
TPH-GRO
(µg/L)
TPH-DRO
(µg/L)
MTBE
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethyl-
benzene
(µg/L)
Total
Xylene
(µg/L)
Naph-
thalene
(µg/L)
1,000 1,000 200 5 1,000 700 10,000 700
10,000 10,000 200 300 3,000 4,000 10,000 700
Initial Screening Levels (µg/L)
TIER 1 Screening Criteria (µg/L)
10/11/95 10.43 94,800 NA NA 17,200 12,300 2,110 8,880 <400
02/01/96 14.46 55,700 NA NA 14,300 5,520 1,080 5,670 620
06/21/96 15.61 49,800 NA NA 17,000 5,100 1,180 5,120 249
09/10/96 15.50 35,300 NA NA 14,800 4,160 1,050 4,610 214
12/10/96 14.50 49,500 NA NA 17,400 5,460 1,160 5,930 315
03/12/97 10.28 49,200 NA <100 21,500 7,340 1,290 6,700 316
06/12/97 9.26 43,400 NA <175 18,000 3,170 1,060 4,830 422
10/01/97 10.27 50,200 NA <25 17,360 6,250 1,240 6,680 415
12/10/97 12.43 54,300 NA <143 25,300 8,400 1,510 8,400 405
03/26/98 11.50 48,800 NA <100 22,200 6,870 1,380 7,150 323
07/14/98 9.85 48,400 NA <200 24,100 9,370 1,340 7,280 275
01/11/99 13.38 38,700 NA <100 22,800 7,450 1,510 7,180 441
04/28/99 12.87 136,000 NA <100 14,100 5,310 1,120 5,770 384
07/20/99 12.62 41,100 NA <100 22,900 6,650 1,460 6,910 361
10/13/99 12.52 32,400 NA <200 20,300 4,840 1,250 6,150 429
05/24/00 13.25 92,800 NA <200 19,100 4,330 987 4,840 271
08/09/00 12.84 17,100 NA <20 2,710 720 112 937 44.3
11/07/00 12.86 39,800 NA <100 17,400 3,900 1,050 4,710 183
02/08/01 14.93 90,400 NA <500 19,000 4,060 1,070 4,980 1,040
05/08/01 13.20 79,300 NA <100 17,300 4,560 1,110 5,160 246
08/16/01 11.50 82,300 NA <100 19,000 5,910 1,280 6,060 266
08/08/02 17.18 104,000 2,900 <400 20,100 5,960 1,600 8,630 <400
11/13/02 18.50
02/19/03 19.24
05/27/03 18.85
03/23/04 18.28
10/09/06 11.43
05/08/07 14.50
11/12/09 14.04
06/29/10 9.84 25,400 39,600 <20 442 477 1,330 8,930 581
02/14/13 16.58 17,700 178,000 <20 2100 103 898 6,050 1,330
09/10/13 16.03 11,200 2,000 <20 749 105 631 4,440 263
11/18/13 17.49 13,600 2,400 <5 1,110 118 743 5,620 296
07/22/14 18.66 12,800 4,300 <5 1,040 109 665 3,340 326
05/14/15 15.12 7,560 1,800 <1 614 32 317 1,950 194
05/03/16 13.70 10,600 3,100 <5 614 24 470 2,620 247
11/18/16 15.60 17,200 4,300 <100 2,770 <250 935 4,820 <250
06/06/18 NM
04/17/19 NM
10/09/19 NM
06/25/20 NM
01/27/22 18.30 3,980 1,100 <5 754 <12 332 772 62
04/21/22 18.11 4,490 1,400 <5 679 <12 388 856 74
07/28/22 19.22 1,920 <1,000 <5 482 <12 157 281 31
10/20/22 18.34 2,190 <1,000 <5 466 <12 184 329 21
09/27/23 13.17 1,920 <1,000 <5 601 <12 117 162 <12
12/12/23 14.15 1,130 <1,000 <5 495 <12 99 91 12
03/20/24 10.67 969 <1,000 <5 340 <12 79 96 12
06/26/24 11.97 1,710 <1,000 <8 485 <12 153 191 14
09/25/24 13.80 2,150 <1,000 <8 651 <12 176 229 24
12/11/24 14.50 2,780 <1,000 <8 768 <12 192 260 31
LNAPL
Well abandoned
LNAPL
LNAPL
LNAPL
LNAPL
Not Sampled - well casing damaged and debris in well
MW-5R
MW-5
Not Sampled - well casing damaged and debris in well
Not Sampled - well casing damaged and debris in well
LNAPL
LNAPL
Not Sampled - well casing damaged and debris in well
Page 3 of 9 Terracon Consultants, Inc.
Table 2
Brent Redd Property
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Groundwater Analytical Results
Sample
Location
Sample
Date
Depth to
Water
(ft-btoc)
TPH-GRO
(µg/L)
TPH-DRO
(µg/L)
MTBE
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethyl-
benzene
(µg/L)
Total
Xylene
(µg/L)
Naph-
thalene
(µg/L)
1,000 1,000 200 5 1,000 700 10,000 700
10,000 10,000 200 300 3,000 4,000 10,000 700
Initial Screening Levels (µg/L)
TIER 1 Screening Criteria (µg/L)
10/11/95 10.25 <500 NA NA <2 <2 <2 <6 <2
02/01/96 14.31 <500 NA NA <2 <2 <2 <6 <2
06/21/96 14.92 <500 NA NA <2 <2 <2 <6 <2
09/10/96 15.05 <500 NA NA <2 <2 <2 <6 <2
12/10/96 14.51 <500 NA NA <2 <2 <2 <6 <2
03/12/97 9.83 <500 NA 403 12.9 <2 <2 <6 <2
06/12/97 8.72 <500 NA 750 3.4 <2 <2 <6 <2
10/01/97 9.97 <500 NA 306 <2 <2 <2 <6 <2
12/10/97 12.24 <500 NA 276 <2 <2 <2 <6 <2
03/26/98 11.35 <500 NA 261 <2 <2 <2 <6 <2
07/14/98 9.99 <500 NA 167 <2 <2 <2 <6 <2
01/11/99 13.03 <500 NA 102 <2 <2 <2 <6 <2
04/28/99 12.46 <500 NA 76.5 <2 <2 <2 <6 <2
07/20/99 11.84 <500 NA 104 <2 <2 <2 <6 <2
10/13/99 11.91 <500 NA 149 <2 <2 <2 <6 <2
05/24/00 12.49 <500 NA 85.3 3.3 <2 <2 <6 <2
08/09/00 12.36 <500 NA 128 <2 <2 <2 <6 <2
11/07/00 12.82 <500 NA 134 <2 <2 <2 <6 <2
02/08/01 14.67 <500 NA 110 <2 <2 <2 <6 <2
05/08/01 12.80 <500 NA 124 <2 <2 <2 <6 <2
08/14/01 12.10 <500 NA 131 <2 <2 <2 <6 <2
08/09/02 16.75 <500 <500 13.6 <2 <2 <2 <6 <2
11/14/02 16.70 <500 <500 8.6 <2 <2 <2 <6 <2
02/19/03 18.45 <500 <500 5.7 <2 <2 <2 <6 <2
11/12/09 14.36
06/29/10 9.61 4,770 1,930 30.2 619 28.9 137 788 97.4
02/14/13 NM NA NA NA NA NA NA NA NA
09/10/13 16.09 4,660 <1,000 <5 <5 <5 43 215 50
11/18/13 16.53 1,000 <1,000 <5 <5 <5 17 68 13
07/22/14 17.82 1,500 <1,000 <1 2 <1 34 126 16
05/13/15 14.68 1,870 <1,000 <1 24 <1 15 66 15
05/03/16 13.42 16,800 24,300 <5 60 <5 72 333 103
11/18/16 15.52 7,310 5,600 <3 68 <8 31 98 16
06/06/18 17.81 2,940 1,600 <5 28 <12 14 50 <12
04/17/19 9.95 6,560 2,200 <5 193 <12 31 87 20
10/09/19 14.05 13,800 13,900 <5 62 <12 32 86 21
06/25/20 14.57 2,180 1,500 <5 53 <12 14 28 <12
01/27/22 17.99 3,420 1,300 <5 33 <12 <12 14 <12
04/21/22 17.68 1,740 <1,000 <5 50 <12 <12 13 <12
07/28/22 18.45 3,220 1,600 <5 40 <12 14 24 <12
10/20/22 18.00 2,010 1,000 <5 23 <12 <12 <12 <12
09/27/23 12.96 4,780 1,300 <5 133 <12 23 49 <12
12/12/23 13.19 2,230 <1,000 <5 39 <12 <12 17 <12
03/20/24 8.70 2,450 1,200 <5 41 <12 30 65 19
06/26/24 9.67 2,180 <1,000 <8 38 <12 26 49 <12
09/25/24 14.10 1,900 <1,000 <8 26 <12 14 <38 <12
12/11/24 14.79 4,550 <1,000 <8 39 <12 20 39 13
MW-7
LNAPL
Page 4 of 9 Terracon Consultants, Inc.
Table 2
Brent Redd Property
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Groundwater Analytical Results
Sample
Location
Sample
Date
Depth to
Water
(ft-btoc)
TPH-GRO
(µg/L)
TPH-DRO
(µg/L)
MTBE
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethyl-
benzene
(µg/L)
Total
Xylene
(µg/L)
Naph-
thalene
(µg/L)
1,000 1,000 200 5 1,000 700 10,000 700
10,000 10,000 200 300 3,000 4,000 10,000 700
Initial Screening Levels (µg/L)
TIER 1 Screening Criteria (µg/L)
05/24/00 12.99 600 NA <5 135 <5 <5 <15 <5
08/09/00 12.64 1,700 NA <5 21.9 <5 <5 <15 <5
11/07/00 12.30 1,900 NA <5 7.2 <5 <5 <15 <5
02/08/01 14.20 2,700 NA <2 95.9 <2 <2 <6 <2
05/08/01 12.70 3,100 NA <2 74.0 <2 <2 15.9 4.7
08/14/01 11.98 3,200 NA <2 45.2 <2 <2 <6 <2
08/08/02 17.04 1,000 640 <5 12.0 <5 <5 <15 <5
11/13/02 18.10 600 <500 <2 112 <2 <2 <6 <2
02/19/03 19.42 6,400 4,300 <2 104 9.5 <2 10.3 3.3
05/28/03 19.21 980 <500 <2 60 3.3 <2 <6 <2
03/24/04 18.93 16,900 E 2,170 <10 106 14 19 27 44
10/10/06 10.95 1,210 <2,000 <1 9 <1 <1 <3 16
05/09/07 13.92 <50 <2,000 <1 14 <1 <1 <3 <1
11/12/09 13.96 14,000 3,900 <2 76 <2 2.6 3.5 <2
06/29/10 9.43 5,450 8,150 <2 75.2 <2 6.81 12.5 7.19
02/14/13 16.58 6,330 <1000 <1 3 <1 <1 <3 <2
09/10/13 17.57 2,260 <1,000 <1 2 <1 <1 <3 <2
11/19/13 17.67 2,830 <1,000 <1 4 <1 <1 <3 <2
07/22/14 18.95 1,700 <1,000 <1 5 <1 <1 <3 7
05/14/15 15.01 2,170 1,100 <1 24 <1 2 10 4
05/04/16 13.29 1,450 <1,000 <5 21 <5 <5 10 <5
11/18/16 15.26 2,020 <1000 <2 10 <5 <5 <5 <5
06/06/18 18.62 11,300 1,800 <5 <5 <12 <12 <12 <12
04/17/19 10.33 6,580 1,500 <5 71 <12 18 54 15
10/09/19 14.66 3,820 2,300 <5 22 <12 <12 <12 <12
06/25/20 15.38 2,810 2,400 <5 34 <12 <12 <12 <12
01/27/22 19.21 3,080 <1,000 <5 <5 <12 <12 <12 <12
04/21/22 19.16 1,900 <1,000 <5 <5 <12 <12 <12 <12
07/28/22 20.44 798 <1,000 <5 6 <12 <12 <12 <12
10/20/22 19.38 2,170 <1,000 <5 26 <12 <12 <12 <12
09/27/23 13.75 2,000 1,100 <5 29 <12 <12 <12 <12
12/12/23 14.95 1,420 1,400 <5 33 <12 <12 <12 <12
03/20/24 11.65 437 <1,000 <5 <5 <12 <12 <12 <12
06/25/24 12.95 848 <1,000 <8 16 <12 <12 <38 <12
09/24/24 14.34 1,960 <1,000 <8 34 <12 <12 <38 <12
12/10/24 15.10 1,590 <1,000 <8 16 <12 <12 <38 <12
MW-14
Page 5 of 9 Terracon Consultants, Inc.
Table 2
Brent Redd Property
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Groundwater Analytical Results
Sample
Location
Sample
Date
Depth to
Water
(ft-btoc)
TPH-GRO
(µg/L)
TPH-DRO
(µg/L)
MTBE
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethyl-
benzene
(µg/L)
Total
Xylene
(µg/L)
Naph-
thalene
(µg/L)
1,000 1,000 200 5 1,000 700 10,000 700
10,000 10,000 200 300 3,000 4,000 10,000 700
Initial Screening Levels (µg/L)
TIER 1 Screening Criteria (µg/L)
05/30/03 19.61 63,000 5,400 <100 11,000 E 5,500 E 1,700 9,100 340
03/25/04 19.22 46,000 7,910 <100 10,700 E 1,670 1,110 5,440 201
10/09/06 12.41 16,700 <2,000 <1 7,700 966 1,630 5,000 303
05/04/16 14.34 6,960 1,300 <5 878 58 269 590 58
11/18/16 15.98 7,090 1,600 <20 2,150 103 474 1,170 66
06/06/18 19.39 2,530 1,400 <5 446 23 126 361 16
04/17/19 10.63 396 <1,000 <5 94 <12 23 17 <12
10/09/19 15.33 1,730 <1,000 <5 474 14 103 121 16
06/25/20 16.12 1,300 <1,000 <5 323 13 66 162 <12
01/27/22 19.66 5,510 1,100 <5 1,740 19 374 663 37
04/21/22 19.51 5,070 <1,000 <5 2,490 21 368 422 32
07/28/22 20.76 8,740 1,400 <5 4,340 27 354 446 41
10/20/22 19.77 8,520 1,200 <5 4,700 38 364 404 37
09/27/23 14.40 4,820 1,100 <5 3,400 <12 99 123 25
12/12/23 15.59 2,870 <1,000 <5 2,110 21 116 92 23
03/20/24 12.89 4,150 <1,000 <5 2,970 22 121 139 27
06/25/24 13.57 3,100 <1,000 <8 1,890 19 116 167 23
09/24/24 15.01 4,100 <1,000 <8 2,060 32 202 334 24
12/10/24 15.72 6,010 <1,000 <8 3,520 42 354 435 49
05/30/03 20.06 82,000 E 5,700 <100 21,000 E 7,400 E 730 8,200 280
10/09/06 12.38 65,100 <2,000 <5 11,200 1,570 1,520 8,780 485
05/08/07 14.52
11/12/09 15.06 41,000 10,000 <40 4,700 1,100 1,100 5,000 360
06/29/10 10.62
02/14/13 17.59 32,000 3,800 <50 8,290 271 668 3,550 227
09/10/13 15.16 20,200 2,400 <25 4,880 170 580 3,120 208
11/19/13 18.56 23,300 2,600 <10 8,140 211 814 4,000 227
07/22/14 19.76 14,100 1,800 <10 4,100 99 576 2,660 178
05/14/15 16.10 12,300 2,300 <1 2,680 51 364 2,260 137
05/03/16 14.55 19,700 4,900 <5 1,760 26 280 1,370 156
11/18/16 16.42 7,500 2,300 <100 3,580 <250 <250 900 <250
06/06/18 19.64 8,830 4,400 <5 1,700 <12 125 504 54
04/17/19 11.05 901 <1,000 <5 41 <12 <12 34 <12
10/09/19 15.73 3,110 1,700 <5 578 <12 54 143 20
06/25/20 16.43 <2,500 3,800 <100 1,910 <250 <250 350 <250
01/27/22 20.01 13,100 2,200 <5 6,690 15 178 580 57
04/21/22 19.85 14,600 2,800 <5 8,320 20 202 644 63
07/28/22 21.07 17,000 4,000 <5 10,300 17 166 577 72
10/20/22 20.12 19,900 4,100 <5 10,500 28 225 759 92
09/27/23 14.80 15,200 2,700 <5 9,330 17 167 309 34
12/12/23 15.88 11,600 2,900 <5 8,990 24 199 421 59
03/20/24 12.71 18,400 2,400 <5 14,300 28 291 617 81
06/25/24 13.75 14,800 2,300 <8 10,700 26 212 527 57
09/24/24 15.48 10,400 1,500 <8 7,550 18 203 311 37
12/10/24 16.15 15,500 1,800 <8 11,400 32 284 508 69
LNAPL
LNAPL
MW-15
MW-16
Page 6 of 9 Terracon Consultants, Inc.
Table 2
Brent Redd Property
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Groundwater Analytical Results
Sample
Location
Sample
Date
Depth to
Water
(ft-btoc)
TPH-GRO
(µg/L)
TPH-DRO
(µg/L)
MTBE
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethyl-
benzene
(µg/L)
Total
Xylene
(µg/L)
Naph-
thalene
(µg/L)
1,000 1,000 200 5 1,000 700 10,000 700
10,000 10,000 200 300 3,000 4,000 10,000 700
Initial Screening Levels (µg/L)
TIER 1 Screening Criteria (µg/L)
05/28/03 20.28 19,000 E 1,900 <20 4,300 E 2,200 E 210 1,500 41
03/24/04 19.77 29,700 E 7,310 <10 4,810 E 2,360 E 238 3,960 E 242
10/09/06 12.31 17,900 <2,000 <1 4,520 196 430 2,000 139
05/08/07 15.42 8,670 <2,000 3 4,670 116 307 1,330 133
11/12/09 15.63 18,000 1,900 6.3 9,100 140 690 2,000 210
06/29/10 11.12 15,700 5,820 3.75 6,120 126 1,430 4,700 272
02/14/13 17.79 19,100 <1000 <20 8,880 32 423 872 121
09/10/13 18.60 12,300 <1,000 <25 6,710 28 318 571 97
11/19/13 18.72 32,800 1,900 <5 16,600 47 737 1,560 186
07/22/14 19.93 18,000 1,200 <10 9,960 27 480 944 95
05/13/15 15.30 19,700 <1,000 2 10,800 24 511 938 158
05/04/16 14.71 20,300 2,600 <5 10,000 20 415 1,200 206
11/18/16 16.87 21,000 3,100 <50 12,700 <50 730 1,220 182
06/06/18 19.84 14,400 3,900 <5 5,620 24 505 676 123
04/17/19 11.34 20,600 8,300 <40 1,930 <100 1,600 4,400 423
10/09/19 16.08 21,200 5,400 <5 10,000 18 915 1,680 266
06/25/20 18.73 21,900 5,100 <50 11,900 <125 924 1,660 194
01/27/22 19.90 20,000 2,100 <5 13,800 25 544 804 135
04/21/22 19.75 19,700 2,500 <5 13,000 28 592 872 144
07/28/22 20.92 30,000 3,000 <5 20,600 33 640 848 165
10/20/22 20.04 21,300 3,100 <5 14,500 33 542 744 134
09/27/23 14.84 24,200 5,800 <5 8,850 27 1,040 2,390 170
12/12/23 15.82 25,300 5,400 <5 15,100 34 1,080 1,590 284
03/20/24 12.13 18,800 3,800 <5 10,500 20 764 1,160 223
06/25/24 13.52 23,400 5,200 <8 11,800 30 1,320 1,890 288
09/24/24 15.59 17,600 3,300 <8 9,100 28 1,010 1,060 198
12/10/24 16.29 20,500 3,300 <8 10,700 37 868 1,070 244
05/28/03 18.49 23,000 E 2,100 <20 8,400 E 1,100 E 27 1,000 47
03/24/04 17.96 16,600 E 6,090 <10 5,410 E 545 E 94 671 120
10/09/06 10.56 5,780 <2,000 <1 243 52.7 127 893 182
05/08/07 14.09 5,270 <2,000 <1 3,270 351 323 379 107
11/12/09 14.04 2,500 720 <2 970 17.0 94 230 55
06/29/10 9.36 477 670 <2 410 <2 7.08 4.89 3.16
02/14/13 15.97 3,640 1,200 <10 834 102 393 744 164
09/10/13 16.75 4,180 1,400 <5 525 116 272 443 34
11/19/13 16.89 3,080 <1,000 <5 378 56 247 510 25
07/22/14 18.06 1,760 <1,000 <10 240 50 183 680 36
05/14/15 14.49 2,170 1,000 <1 175 33 88 276 17
05/04/16 12.95 404 <1,000 <5 12 <5 13 18 6
11/18/16 15.17 2,930 <1,000 <10 258 <25 206 168 <25
06/06/18 18.01 3,310 1,200 <5 306 35 230 381 33
04/17/19 9.19 <125 <1,000 <5 5 <12 <12 <12 <12
10/09/19 14.24 1,270 <1,000 <5 812 <12 <12 <12 16
06/25/20 14.89 <1,125 <1,000 <50 1,100 <125 <125 <125 <125
01/27/22 18.29 965 <1,100 <5 460 <12 74 42 <12
04/21/22 18.09 959 <1,000 <5 412 13 113 162 24
07/28/22 19.21 588 <1,000 <5 349 <12 44 17 <12
10/20/22 18.35 <125 <1,000 <5 115 <12 <12 <12 <12
09/27/23 13.19 <125 2,100 <5 46 <12 <12 <12 <12
12/12/23 14.14 982 2,300 <5 982 <12 <12 <12 <12
03/20/24 9.41 <125 2,000 <5 <5 <12 <12 <12 15
06/26/24 11.74 <125 1,700 <8 11 <12 <12 <38 <12
MW-18
MW-17
Page 7 of 9 Terracon Consultants, Inc.
Table 2
Brent Redd Property
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Groundwater Analytical Results
Sample
Location
Sample
Date
Depth to
Water
(ft-btoc)
TPH-GRO
(µg/L)
TPH-DRO
(µg/L)
MTBE
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethyl-
benzene
(µg/L)
Total
Xylene
(µg/L)
Naph-
thalene
(µg/L)
1,000 1,000 200 5 1,000 700 10,000 700
10,000 10,000 200 300 3,000 4,000 10,000 700
Initial Screening Levels (µg/L)
TIER 1 Screening Criteria (µg/L)
09/24/24 13.97 686 1,200 <8 686 <12 <12 <38 <12
12/11/24 14.65 1,830 <1,000 <8 1,580 <12 <12 <38 <12
Page 8 of 9 Terracon Consultants, Inc.
Table 2
Brent Redd Property
148 East Center Street, Monticello, UT
(Facility ID 5000003, Release Site GZQ)
Groundwater Analytical Results
Sample
Location
Sample
Date
Depth to
Water
(ft-btoc)
TPH-GRO
(µg/L)
TPH-DRO
(µg/L)
MTBE
(µg/L)
Benzene
(µg/L)
Toluene
(µg/L)
Ethyl-
benzene
(µg/L)
Total
Xylene
(µg/L)
Naph-
thalene
(µg/L)
1,000 1,000 200 5 1,000 700 10,000 700
10,000 10,000 200 300 3,000 4,000 10,000 700
Initial Screening Levels (µg/L)
TIER 1 Screening Criteria (µg/L)
01/27/22 19.09 687 <1,000 <5 25 <12 21 43 14
04/21/22 18.89 <125 <1,000 <5 10 <12 <12 15 <12
07/28/22 20.08 <125 <1,000 <5 8 <12 <12 <12 <12
10/20/22 19.25 <125 <1,000 <5 8 <12 <12 <12 <12
09/27/23 14.12 <125 <1,000 <5 5 <12 <12 <12 <12
12/12/23 15.05 <10 <1,000 <4 0.5 <1 <1 <1 <1
03/20/24 10.97 <125 <1,000 <5 <5 <12 <12 <12 <12
06/26/24 12.71 <125 <1,000 <8 9 <12 <12 <38 <12
09/25/24 14.97 <125 <1,000 <8 12 <12 12 <38 <12
12/10/24 15.65 <125 <1,000 <8 11 <12 <12 <38 <12
01/27/22 17.27 <125 <1,000 <5 9 <12 <12 <12 <12
04/21/22 16.94 <125 <1,000 <5 9 <12 <12 <12 <12
07/28/22 17.65 <125 <1,000 <5 7 <12 <12 <12 <12
10/20/22 17.28 <125 <1,000 <5 <5 <12 <12 <12 <12
09/27/23 12.22 <125 <1,000 <5 18 <12 <12 <12 <12
12/12/23 12.69 <12 <1,000 <5 11 <12 <12 <12 <12
03/20/24 8.61 <125 <1,000 <5 <5 <12 <12 <12 <12
06/26/24 9.60 <125 <1,000 <8 <5 <12 <12 <38 <12
09/25/24 13.17 <125 <1,000 <8 57 <12 <12 <38 <12
12/11/24 13.85 <125 <1,000 <8 15 <12 <12 <38 <12
01/27/22 18.72 <125 <1,000 <5 <5 <12 <12 <12 <12
04/21/22 18.20 <125 <1,000 <5 <5 <12 <12 <12 <12
07/28/22 18.50 <125 <1,000 <5 <5 <12 <12 <12 <12
10/20/22 18.49 <125 <1,000 <5 <5 <12 <12 <12 <12
09/27/23 12.87 <125 <1,000 <5 <5 <12 <12 <12 <12
12/12/23 12.46 <125 <1,000 <5 <5 <12 <12 <12 <12
03/20/24 7.15 <125 <1,000 <5 <5 <12 <12 <12 <12
06/26/24 7.15 <125 <1,000 <8 <5 <12 <12 <38 <12
09/25/24 14.53 <125 <1,000 <8 <5 <12 <12 <38 <12
12/11/24 15.34 <125 <1,000 <8 <5 <12 <12 <38 <12
NOTES:
ft-btoc = feet below top of casing.
LNAPL = Light Nonaqueous Phase Liquid
MTBE = methyl tertiary butyl ether
NA = not analyzed
NM = not measured
TPH-DRO = total petroleum hydrocarbons diesel-range organics
TPH-GRO = total petroleum hydrocarbons gasoline-range organics
µg/L = micrograms per liter
Bold type indicates concentration exceeds laboratory reporting limit.
<= Not detected at or above the indicated laboratory reporting limit.
Concentration exceeds the Initial Screening Level (ISL)
Concentration exceeds the Tier 1 Screening Criteria
MW-19
MW-20
MW-21
Page 9 of 9 Terracon Consultants, Inc.
Appendix C
Chain of Custody Documentation and Laboratory Data
The analyses presented on this report were performed in accordance with the
National Environmental Laboratory Accreditation Program (NELAP) unless
noted in the comments, flags, or case narrative. If the report is to be used for
regulatory compliance, it should be presented in its entirety, and not be
altered.
Client Service Contact: 801.262.7299
Terracon IHI
Attn: Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
Work Order: 24L1087
Project: DERR Brent Redd LUST, Monticello,
Project # AL067003 / GZQ-57-TER, Task 1f
12/18/2024
Approved By:
Mark Broadhead, Project Manager
9632 South 500 West Sandy, Utah 84070
Serving the Intermountain West since 1953
801.262.7299 Main 866.792.0093 Fax www.ChemtechFord.com
Page 1 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: B-3R
Lab ID: 24L1087-01Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/10/24 13:10
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/12/2412/12/240.100 EPA 8260D/5030B4.90Benzene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B1.20Ethylbenzene
mg/L 12/12/2412/12/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.373Naphthalene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.126Toluene
mg/L 12/12/2412/12/240.750 EPA 8260D/5030B5.34Xylenes, total
Gasoline Range
mg/L 12/12/2412/12/240.750 EPA 8260B/C /5030A/[CALC]29.2Gasoline Range Organics
Diesel Range
mg/L 12/12/2412/12/241.0 EPA 8015 C7.4Diesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 2 of 16Page 2 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: MW-14
Lab ID: 24L1087-02Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/10/24 13:47
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/16/2412/16/240.005 EPA 8260D/5030B0.016Benzene
mg/L 12/16/2412/16/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L 12/16/2412/16/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/16/2412/16/240.012 EPA 8260D/5030BNDNaphthalene
mg/L 12/16/2412/16/240.012 EPA 8260D/5030BNDToluene
mg/L 12/16/2412/16/240.038 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/L 12/16/2412/16/240.125 EPA 8260B/C /5030A/[CALC]1.59Gasoline Range Organics
Diesel Range
mg/L 12/12/2412/12/241.0 EPA 8015 CNDDiesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 3 of 16Page 3 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: MW-15
Lab ID: 24L1087-03Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/10/24 15:22
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/12/2412/12/240.100 EPA 8260D/5030B3.52Benzene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.354Ethylbenzene
mg/L 12/12/2412/12/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.049Naphthalene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.042Toluene
mg/L 12/12/2412/12/240.038 EPA 8260D/5030B0.435Xylenes, total
Gasoline Range
mg/L 12/12/2412/12/240.125 EPA 8260B/C /5030A/[CALC]6.01Gasoline Range Organics
Diesel Range
mg/L 12/12/2412/12/241.0 EPA 8015 CNDDiesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 4 of 16Page 4 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: MW-16
Lab ID: 24L1087-04Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/10/24 15:40
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/12/2412/12/240.100 EPA 8260D/5030B11.4Benzene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.284Ethylbenzene
mg/L 12/12/2412/12/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.069Naphthalene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.032Toluene
mg/L 12/12/2412/12/240.038 EPA 8260D/5030B0.508Xylenes, total
Gasoline Range
mg/L 12/12/2412/12/240.125 EPA 8260B/C /5030A/[CALC]15.5Gasoline Range Organics
Diesel Range
mg/L 12/12/2412/12/241.0 EPA 8015 C1.8Diesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 5 of 16Page 5 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: MW-17
Lab ID: 24L1087-05Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/10/24 15:00
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/12/2412/12/240.100 EPA 8260D/5030B10.7Benzene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.868Ethylbenzene
mg/L 12/12/2412/12/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.244Naphthalene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.037Toluene
mg/L 12/12/2412/12/240.038 EPA 8260D/5030B1.07Xylenes, total
Gasoline Range
mg/L 12/12/2412/12/240.125 EPA 8260B/C /5030A/[CALC]20.5Gasoline Range Organics
Diesel Range
mg/L 12/12/2412/12/241.0 EPA 8015 C3.3Diesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 6 of 16Page 6 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: MW-19
Lab ID: 24L1087-06Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/10/24 16:10
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/16/2412/16/240.005 EPA 8260D/5030B0.011Benzene
mg/L 12/16/2412/16/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L 12/16/2412/16/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/16/2412/16/240.012 EPA 8260D/5030BNDNaphthalene
mg/L 12/16/2412/16/240.012 EPA 8260D/5030BNDToluene
mg/L 12/16/2412/16/240.038 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/L 12/16/2412/16/240.125 EPA 8260B/C /5030A/[CALC]NDGasoline Range Organics
Diesel Range
mg/L 12/12/2412/12/241.0 EPA 8015 CNDDiesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 7 of 16Page 7 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: MW-18
Lab ID: 24L1087-07Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/11/24 9:52
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/12/2412/12/240.050 EPA 8260D/5030B1.58Benzene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L 12/12/2412/12/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDNaphthalene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDToluene
mg/L 12/12/2412/12/240.038 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/L 12/12/2412/12/240.125 EPA 8260B/C /5030A/[CALC]1.83Gasoline Range Organics
Diesel Range
mg/L 12/12/2412/12/241.0 EPA 8015 CNDDiesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 8 of 16Page 8 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: MW-5R
Lab ID: 24L1087-08Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/11/24 10:57
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/12/2412/12/240.005 EPA 8260D/5030B0.768Benzene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.192Ethylbenzene
mg/L 12/12/2412/12/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.031Naphthalene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDToluene
mg/L 12/12/2412/12/240.038 EPA 8260D/5030B0.260Xylenes, total
Gasoline Range
mg/L 12/12/2412/12/240.125 EPA 8260B/C /5030A/[CALC]2.78Gasoline Range Organics
Diesel Range
mg/L 12/12/2412/12/241.0 EPA 8015 CNDDiesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 9 of 16Page 9 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: MW-20
Lab ID: 24L1087-09Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/11/24 12:30
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/12/2412/12/240.005 EPA 8260D/5030B0.015Benzene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L 12/12/2412/12/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDNaphthalene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDToluene
mg/L 12/12/2412/12/240.038 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/L 12/12/2412/12/240.125 EPA 8260B/C /5030A/[CALC]NDGasoline Range Organics
Diesel Range
mg/L 12/18/2412/16/241.0 EPA 8015 CNDDiesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 10 of 16Page 10 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: MW-7
Lab ID: 24L1087-10Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/11/24 12:50
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/12/2412/12/240.005 EPA 8260D/5030B0.039Benzene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.020Ethylbenzene
mg/L 12/12/2412/12/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/12/2412/12/240.012 EPA 8260D/5030B0.013Naphthalene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDToluene
mg/L 12/12/2412/12/240.038 EPA 8260D/5030B0.039Xylenes, total
Gasoline Range
mg/L 12/12/2412/12/240.125 EPA 8260B/C /5030A/[CALC]4.55Gasoline Range Organics
Diesel Range
mg/L 12/18/2412/16/241.0 EPA 8015 CNDDiesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 11 of 16Page 11 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: MW-21
Lab ID: 24L1087-11Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/11/24 13:33
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/12/2412/12/240.005 EPA 8260D/5030BNDBenzene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L 12/12/2412/12/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDNaphthalene
mg/L 12/12/2412/12/240.012 EPA 8260D/5030BNDToluene
mg/L 12/12/2412/12/240.038 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/L 12/12/2412/12/240.125 EPA 8260B/C /5030A/[CALC]NDGasoline Range Organics
Diesel Range
mg/L 12/18/2412/16/241.0 EPA 8015 CNDDiesel Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 12 of 16Page 12 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: Field Blank
Lab ID: 24L1087-12Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/11/24 13:51
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/13/2412/13/240.005 EPA 8260D/5030BNDBenzene
mg/L 12/13/2412/13/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L 12/13/2412/13/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L J-LOW-L12/13/2412/13/240.012 EPA 8260D/5030BNDNaphthalene
mg/L 12/13/2412/13/240.012 EPA 8260D/5030BNDToluene
mg/L 12/13/2412/13/240.038 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/L 12/13/2412/13/240.125 EPA 8260B/C /5030A/[CALC]NDGasoline Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 13 of 16Page 13 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Sample ID: Trip Blank
Lab ID: 24L1087-13Matrix: Water
Flag(s)Units
Analysis
Date/Time
Date Sampled: 12/10/24 0:00
Preparation
Date/Time
Sampled By: Mark Lilly
Minimum
Reporting
Limit MethodResult
MBTEXn
mg/L 12/13/2412/13/240.005 EPA 8260D/5030BNDBenzene
mg/L 12/13/2412/13/240.012 EPA 8260D/5030BNDEthylbenzene
mg/L 12/13/2412/13/240.008 EPA 8260D/5030BNDMethyl-tert-butyl ether (MTBE)
mg/L J-LOW-L12/13/2412/13/240.012 EPA 8260D/5030BNDNaphthalene
mg/L 12/13/2412/13/240.012 EPA 8260D/5030BNDToluene
mg/L 12/13/2412/13/240.038 EPA 8260D/5030BNDXylenes, total
Gasoline Range
mg/L 12/13/2412/13/240.125 EPA 8260B/C /5030A/[CALC]NDGasoline Range Organics
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 14 of 16Page 14 of 16
xx
Chemtech-Ford Laboratories
Serving the Intermountain West Since 1953
Certificate of Analysis
9632 South 500 West
Sandy, UT 84070
O:[phone] F: [phone]
www.ChemtechFord.com
Terracon IHI
Amy Austin
6949 South High Tech Drive
Midvale, UT 84047
PO#:
Receipt:
Date Reported:
Project Name:
Project # AL067003 / GZQ-57-TER, Task 1f
12/12/24 12:28 @ -0.5 °C
12/18/2024
DERR Brent Redd LUST, Monticello, Project #
AL067003 / GZQ-57-TER, Task 1f
Report Footnotes
Abbreviations
ND = Not detected at the corresponding Minimum Reporting Limit (MRL).
1 mg/L = one milligram per liter or 1 mg/kg = one milligram per kilogram = 1 part per million.
1 ug/L = one microgram per liter or 1 ug/kg = one microgram per kilogram = 1 part per billion.
1 ng/L = one nanogram per liter or 1 ng/kg = one nanogram per kilogram = 1 part per trillion.
On calculated parameters, there may be a slight difference between summing the rounded values shown on the report
vs the unrounded values used in the calculation.
Flag Descriptions
J-LOW-L = Estimated low due to low recovery of LCS
Project Name: DERR Brent Redd LUST, Monticello, Project # AL0 CtF WO#: 24L1087
www.ChemtechFord.com
Page 15 of 16Page 15 of 16
Page 16 of 16
Appendix D
Mann-Kendall Statistical Evaluation Model
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page 1 of 10]
HISTORICAL GROUNDWATER DATABASE
WELL ID:B-3R MW-5R MW-7 MW-14 MW-15 MW-16 MW-17 MW-18 MW-19 MW-20
Sampling
Event Date
1 1/27/2022 754 33 <5 1740 6690 13800 460 25 9
2 4/21/2022 679 50 <5 2490 8320 13000 412 10 9
3 7/28/2022 482 40 6 4340 10300 20600 349 8 7
4 10/20/2022 466 23 26 4700 10500 14500 115 8 <5
5 9/27/2023 5930 601 133 29 3400 9330 8850 46 5 18
6 12/12/2023 5440 495 39 33 2110 8990 15100 982 0.5 11
7 3/20/2024 4090 340 41 <5 2970 14300 10500 <5 <5 <5
8 6/25/2024 3440 485 38 16 1890 10700 11800 11 9 <5
9 9/24/2024 3490 651 26 34 2060 7550 9100 686 12 57
10 12/10/2024 4900 768 39 16 3520 11400 10700 1580 11 15
NOTES:
ADEQUACY OF DATABASE FOR TREND ANALYSIS
HISTORICAL GROUNDWATER MONITORING DATA
Instructions:In spaces provided below, record historical groundwater monitoring results for wells located inside plume area. Do
not include upgradient wells or background wells in this stability evaluation.
Insufficient Data Available: Fewer than four independent samples are available from each well.
Select action:Conduct additional groundwater monitoring and re-evaluate,OR
NOTES: Yellow highlighted results were less than the laboratory's reporting limit. Half of the reporting limit was used for the calculations.
Benzene Concentration (µg/L)
Instructions: This form can be used to characterize a groundwater plume as either stable, diminishing, or expanding based on
concentration trends. For meaningful results, the historical database should include four or more groundwater sampling events at two
or more monitoring wells located inside the plume area. Evaluate database in space provided and indicate selected action ().Note:
This Worksheet #4f may not be useful for fluctuating concentration trends.
Sufficient Data Available: Four or more independent samples (i.e., different sampling dates) are available
from each well in plume area:
Complete one Statistical Analysis Worksheet (page 2 of 3) for each monitoring well in plume to evaluate trends in sampling
data. Record results for all wells on Summary Worksheet (page 3 of 3).
Assume expanding plume condition and proceed with risk-based site evaluation.
0
5000
10000
15000
20000
25000
1/
2
7
/
2
0
2
2
4/
2
7
/
2
0
2
2
7/
2
6
/
2
0
2
2
10
/
2
4
/
2
0
2
2
1/
2
2
/
2
0
2
3
4/
2
2
/
2
0
2
3
7/
2
1
/
2
0
2
3
10
/
1
9
/
2
0
2
3
1/
1
7
/
2
0
2
4
4/
1
6
/
2
0
2
4
7/
1
5
/
2
0
2
4
10
/
1
3
/
2
0
2
4
Be
n
z
e
n
e

C
o
n
c
e
n
t
r
a
t
i
o
n

(
µ
g
/
L
)
Sampling Dates
INSTRUCTIONS: Using input data sheet, plot benzene concentration versus time for each well
B-3R
MW-5R
MW-7
MW-14
MW-15
MW-16
MW-17
MW-18
MW-19
MW-20
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page 2 of 10]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)5930 5440 4090 3440 3490 4900
Row 1: Compare to Event 1:-1 -1 -1 -1 -1 -5
Row 2: Compare to Event 2:-1 -1 -1 -1 -4
Row 3: Compare to Event 3:-1 -1 1 -1
Row 4: Compare to Event 4:1 1 2
Row 5: Compare to Event 5:1 1
Row 6: Compare to Event 6:0
Row 7: Compare to Event 7:0
Row 8: Compare to Event 8:0
Row 9: Compare to Event 9:0
Mann-Kendall Statistic (S) = TOTAL -7
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4
± 5 Trend Is Present (90% Confidence)
± 6  S<0 Diminishing Plume
± 7 X  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend (i.e., expanding plume or diminishing plume):
Total No. of Sampling Events
Confidence Level Chart Stability Evaluation Results
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
MANN-KENDALL ANALYSIS OF PLUME
B-3R
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page 3 of 10]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)754 679 482 466 601 495 340 485 651 768
Row 1: Compare to Event 1:-1 -1 -1 -1 -1 -1 -1 -1 1 -7
Row 2: Compare to Event 2:-1 -1 -1 -1 -1 -1 -1 1 -6
Row 3: Compare to Event 3:-1 1 1 -1 1 1 1 3
Row 4: Compare to Event 4:1 1 -1 1 1 1 4
Row 5: Compare to Event 5:-1 -1 -1 1 1 -1
Row 6: Compare to Event 6:-1 -1 1 1 0
Row 7: Compare to Event 7:1 1 1 3
Row 8: Compare to Event 8:1 1 2
Row 9: Compare to Event 9:1 1
Mann-Kendall Statistic (S) = TOTAL -1
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 X Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4
± 5 Trend Is Present (90% Confidence)
± 6  S<0 Diminishing Plume
± 7  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
MANN-KENDALL ANALYSIS OF PLUME
MW-5R
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
Total No. of Sampling Events
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend (i.e., expanding plume or diminishing plume):
Confidence Level Chart Stability Evaluation Results
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page 4 of 10]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)33 50 40 23 133 39 41 38 26 39
Row 1: Compare to Event 1:1 1 -1 1 1 1 1 -1 1 5
Row 2: Compare to Event 2:-1 -1 1 -1 -1 -1 -1 -1 -6
Row 3: Compare to Event 3:-1 1 -1 1 -1 -1 -1 -3
Row 4: Compare to Event 4:1 1 1 1 1 1 6
Row 5: Compare to Event 5:-1 -1 -1 -1 -1 -5
Row 6: Compare to Event 6:1 -1 -1 0 -1
Row 7: Compare to Event 7:-1 -1 -1 -3
Row 8: Compare to Event 8:-1 1 0
Row 9: Compare to Event 9:1 1
Mann-Kendall Statistic (S) = TOTAL -6
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4
± 5 Trend Is Present (90% Confidence)
± 6 X  S<0 Diminishing Plume
± 7  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
MW-7
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend (i.e., expanding plume or diminishing plume):
Confidence Level Chart Stability Evaluation Results
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
MANN-KENDALL ANALYSIS OF PLUME
Total No. of Sampling Events
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page 5 of 10]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)2.5 2.5 6 26 29 33 2.5 16 34 16
Row 1: Compare to Event 1:0 1 1 1 1 0 1 1 1 7
Row 2: Compare to Event 2:1 1 1 1 0 1 1 1 7
Row 3: Compare to Event 3:1 1 1 -1 1 1 1 5
Row 4: Compare to Event 4:1 1 -1 -1 1 -1 0
Row 5: Compare to Event 5:1 -1 -1 1 -1 -1
Row 6: Compare to Event 6:-1 -1 1 -1 -2
Row 7: Compare to Event 7:1 1 1 3
Row 8: Compare to Event 8:1 0 1
Row 9: Compare to Event 9:-1 -1
Mann-Kendall Statistic (S) = TOTAL 19
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4
± 5 Trend Is Present (90% Confidence)
± 6  S<0 Diminishing Plume
± 7  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15
± 16
± 17
± 18
± 19 X
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
MANN-KENDALL ANALYSIS OF PLUME
MW-14
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
Confidence Level Chart Stability Evaluation Results
Total No. of Sampling Events
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend** (i.e., expanding plume or diminishing plume): **Extended S values with
data from Gilbert RO (1987). Statistical Methods for Environmental Pollution Monitoring. New York: Van Nostrand Reinhold. Accessed on 1/13/25 via
https://help.healthycities.org/hc/en-us/articles/233420187-Mann-Kendall-test-for-trend-overview
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page 6 of 10]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)1740 2490 4340 4700 3400 2110 2970 1890 2060 3520
Row 1: Compare to Event 1:1 1 1 1 1 1 1 1 1 9
Row 2: Compare to Event 2:1 1 1 -1 1 -1 -1 1 2
Row 3: Compare to Event 3:1 -1 -1 -1 -1 -1 -1 -5
Row 4: Compare to Event 4:-1 -1 -1 -1 -1 -1 -6
Row 5: Compare to Event 5:-1 -1 -1 -1 1 -3
Row 6: Compare to Event 6:1 -1 -1 1 0
Row 7: Compare to Event 7:-1 -1 1 -1
Row 8: Compare to Event 8:1 1 2
Row 9: Compare to Event 9:1 1
Mann-Kendall Statistic (S) = TOTAL -1
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 X Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4
± 5 Trend Is Present (90% Confidence)
± 6  S<0 Diminishing Plume
± 7  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend (i.e., expanding plume or diminishing plume):
Confidence Level Chart Stability Evaluation Results
Total No. of Sampling Events
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
MANN-KENDALL ANALYSIS OF PLUME
MW-15
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page 7 of 10]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)6690 8320 10300 10500 9330 8990 14300 10700 7550 11400
Row 1: Compare to Event 1:1 1 1 1 1 1 1 1 1 9
Row 2: Compare to Event 2:1 1 1 1 1 1 -1 1 6
Row 3: Compare to Event 3:1 -1 -1 1 1 -1 1 1
Row 4: Compare to Event 4:-1 -1 1 1 -1 1 0
Row 5: Compare to Event 5:-1 1 1 -1 1 1
Row 6: Compare to Event 6:1 1 -1 1 2
Row 7: Compare to Event 7:-1 -1 -1 -3
Row 8: Compare to Event 8:-1 1 0
Row 9: Compare to Event 9:1 1
Mann-Kendall Statistic (S) = TOTAL 17
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4
± 5 Trend Is Present (90% Confidence)
± 6  S<0 Diminishing Plume
± 7  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15
± 16
± 17 X
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
MANN-KENDALL ANALYSIS OF PLUME
MW-16
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend** (i.e., expanding plume or diminishing plume): **Extended S values with
data from Gilbert RO (1987). Statistical Methods for Environmental Pollution Monitoring. New York: Van Nostrand Reinhold. Accessed on 1/13/25 via
https://help.healthycities.org/hc/en-us/articles/233420187-Mann-Kendall-test-for-trend-overview
Confidence Level Chart Stability Evaluation Results
Total No. of Sampling Events
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page 8 of 10]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)13800 13000 20600 14500 8850 15100 10500 11800 9100 10700
Row 1: Compare to Event 1:-1 1 1 -1 1 -1 -1 -1 -1 -3
Row 2: Compare to Event 2:1 1 -1 1 -1 -1 -1 -1 -2
Row 3: Compare to Event 3:-1 -1 -1 -1 -1 -1 -1 -7
Row 4: Compare to Event 4:-1 1 -1 -1 -1 -1 -4
Row 5: Compare to Event 5:1 1 1 1 1 5
Row 6: Compare to Event 6:-1 -1 -1 -1 -4
Row 7: Compare to Event 7:1 -1 1 1
Row 8: Compare to Event 8:-1 -1 -2
Row 9: Compare to Event 9:1 1
Mann-Kendall Statistic (S) = TOTAL -15
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4
± 5 Trend Is Present (90% Confidence)
± 6  S<0 Diminishing Plume
± 7  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15 X
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
Total No. of Sampling Events
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
Confidence Level Chart Stability Evaluation Results
MANN-KENDALL ANALYSIS OF PLUME
MW-17
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend (i.e., expanding plume or diminishing plume):
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page 9 of 10]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)460 412 349 115 46 982 2.5 11 686 1580
Row 1: Compare to Event 1:-1 -1 -1 -1 1 -1 -1 1 1 -3
Row 2: Compare to Event 2:-1 -1 -1 1 -1 -1 1 1 -2
Row 3: Compare to Event 3:-1 -1 1 -1 -1 1 1 -1
Row 4: Compare to Event 4:-1 1 -1 -1 1 1 0
Row 5: Compare to Event 5:1 -1 -1 1 1 1
Row 6: Compare to Event 6:-1 -1 -1 1 -2
Row 7: Compare to Event 7:1 1 1 3
Row 8: Compare to Event 8:1 1 2
Row 9: Compare to Event 9:1 1
Mann-Kendall Statistic (S) = TOTAL -1
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 X Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4
± 5 Trend Is Present (90% Confidence)
± 6  S<0 Diminishing Plume
± 7  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
MANN-KENDALL ANALYSIS OF PLUME
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
Total No. of Sampling Events
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
MW-18
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend (i.e., expanding plume or diminishing plume):
Confidence Level Chart Stability Evaluation Results
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page NOT USED]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)25 10 8 8 5 0.5 2.5 9 12 11
Row 1: Compare to Event 1:-1 -1 -1 -1 -1 -1 -1 -1 -1 -9
Row 2: Compare to Event 2:-1 -1 -1 -1 -1 -1 1 1 -4
Row 3: Compare to Event 3:0 -1 -1 -1 1 1 1 0
Row 4: Compare to Event 4:-1 -1 -1 1 1 1 0
Row 5: Compare to Event 5:-1 -1 1 1 1 1
Row 6: Compare to Event 6:1 1 1 1 4
Row 7: Compare to Event 7:1 1 1 3
Row 8: Compare to Event 8:1 1 2
Row 9: Compare to Event 9:-1 -1
Mann-Kendall Statistic (S) = TOTAL -4
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4 X
± 5 Trend Is Present (90% Confidence)
± 6  S<0 Diminishing Plume
± 7  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
MW-19
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend (i.e., expanding plume or diminishing plume):
Confidence Level Chart Stability Evaluation Results
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
MANN-KENDALL ANALYSIS OF PLUME
Total No. of Sampling Events
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page NOT USED]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)9 9 7 2.5 18 11 2.5 2.5 57 15
Row 1: Compare to Event 1:0 -1 -1 1 1 -1 -1 1 1 0
Row 2: Compare to Event 2:-1 -1 1 1 -1 -1 1 1 0
Row 3: Compare to Event 3:-1 1 1 -1 -1 1 1 1
Row 4: Compare to Event 4:1 1 0 0 1 1 4
Row 5: Compare to Event 5:-1 -1 -1 1 -1 -3
Row 6: Compare to Event 6:-1 -1 1 1 0
Row 7: Compare to Event 7:0 1 1 2
Row 8: Compare to Event 8:1 1 2
Row 9: Compare to Event 9:-1 -1
Mann-Kendall Statistic (S) = TOTAL 5
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4
± 5 X Trend Is Present (90% Confidence)
± 6  S<0 Diminishing Plume
± 7  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
MANN-KENDALL ANALYSIS OF PLUME
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
Total No. of Sampling Events
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
MW-20
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend (i.e., expanding plume or diminishing plume):
Confidence Level Chart Stability Evaluation Results
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page NOT USED]
STATISTICAL ANALYSIS OF GROUNDWATER PLUME STABILITY
Step 2: Data Comparison: Complete Row 1, comparing the results of Events 2, 3 etc. to Event 1, as follows:
If Concentration of Event x > Event 1: Enter 1
If Concentration of Event x = Event 1: Enter 0
If Concentration of Event x < Event 1: Enter -1
Complete all Rows in same manner until all sampling events are complete.
Well ID:
Event 1 Event 2 Event 3 Event 4 Event 5 Event 6 Event 7 Event 8 Event 9 Event 10 Sum Rows
benzene (mg/L)0.0.0.0.0.0.
Row 1: Compare to Event 1:0 0 0 0 0 0
Row 2: Compare to Event 2:0 0 0 0 0
Row 3: Compare to Event 3:0 0 0 0
Row 4: Compare to Event 4:0 0 0
Row 5: Compare to Event 5:0 0
Row 6: Compare to Event 6:0
Row 7: Compare to Event 7:0
Row 8: Compare to Event 8:0
Row 9: Compare to Event 9:0
Mann-Kendall Statistic (S) = TOTAL 0
S No Trend Indicated Stable Plume
Value 4 5 6 7 8 9 10
± 1 Trend May Be Present* (70%Confidence<90%)
± 2  S<0 Potentially Diminishing Plume
± 3  S>0 Potentially Expanding Plume
± 4
± 5 Trend Is Present (90% Confidence)
± 6  S<0 Diminishing Plume
± 7  S>0 Expanding Plume
± 8
± 9
± 10
± 11
± 12
± 13
± 14
± 15
INSTRUCTIONS FOR USE
The Mann-Kendall statistic can be used to define the stability condition of a groundwater plume (i.e., stable, diminishing or
expanding) based on concentration trends at individual wells. For each monitoring well located in plume area for which 4 or more
independent sampling events are available, follow the steps described below. Complete a separate form for each well.
0
CHARACTERIZATION OF GROUNDWATER PLUME BASED ON DATA FROM THIS WELL
Use the confidence Level Chart with the Mann-Kendall Statistic computed above (S) and the number of sampling events to estimate
confidence level in the presence of a plume trend (i.e., expanding plume or diminishing plume):
Confidence Level Chart Stability Evaluation Results
Step 1: Well Data: Enter Well ID No. and benzene concentrations for each sampling event (i.e. data from page 1). Include only
events for which numeric or ND values are available. Do not include Not Sampled (NS) or PSH events.
Step 3: Mann-Kendall Statistic: Sum across each row (e.g., 0+0+-1+-1+0=-2) and record in far right hand column. Sum right hand
column down to get TOTAL sum. This TOTAL value represents Mann-Kendall Statistic "S" for the data from this well.
Step 4: Results:Use Confidence Level Chart to determine % confidence in plume trend based on S value & number of sampling
events.
MANN-KENDALL ANALYSIS OF PLUME
Total No. of Sampling Events
*Trend May Be Present: For this case, additional monitoring
data is required to confirm presence of trend. To proceed with
RBCA evaluation, assume stable plume for S<0 and assume
expanding plume for S>0.
No Trend
Indicated
Trend May Be Present
(70%Conf.<90%)
Trend is Present
(>90% Confidence)
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.
WORKSHEET #4f
Statistical Evaluation of Plume Stability [Page 10 of 10]
SUMMARY OF RESULTS: GROUNDWATER PLUME STABILITY CONDITION
NOTES:
Discuss consistency of findings among wells, conclusion regarding total plume stability condition, need for further evaluation, etc.
MW-14
Well ID
No. of Sampling
Events
Mann-Kendall
Statistic, S Plume Trend
INSTRUCTIONS: Record results of statistical trend analysis for each monitoring well located inside plume area. Provide brief
discussion regarding significance of findings.
RESULTS OF MANN-KENDALL ANALYSIS
Potentially diminishing plume
Stable
Stable
Expanding plume
-7
-1
-6
6
10
10
10
10
10
MW-15
MW-16
MW-17
MW-18
B-3R
MW-5R
MW-7 10
10
Stable
Expanding plume
Potentially diminishing plume
Stable
19
-1
17
-15
MW-19
MW-20
-1
-4
5
Stable
Stable10
10
Plume Trend: Stable, Potentially Diminishing, Diminishing, Potentially Expanding, or
Expanding as determined from Confidence Level Chart.
DISCUSSION
modified from  Groundwater Services, Inc. (GSI), published in the "Guidelines for Utah's Corrective Action Process for Leaking Underground Storage Tank Sites", UDEQ, 1998.